WO2007007322A2

WO2007007322A2 - Three-dimensional display matrices on flexible substrates and methods for fabricating same

Info

Publication number: WO2007007322A2
Application number: PCT/IL2006/000791
Authority: WO
Inventors: Avi Alkabetz; Ofer Gepstein
Original assignee: Avi Alkabetz; Ofer Gepstein
Priority date: 2005-07-08
Filing date: 2006-07-09
Publication date: 2007-01-18
Also published as: WO2007007322A3

Abstract

Flexible three-dimensional (3D) display matrices include each a plurality of displays positioned substantially in a single plane on a flexible substrate and a plurality of flexible conductor harnesses for allowing addressing and control of each display, each harness extending at least partially into an out-of-plane direction relative to the single plane. In some embodiments, the substrate includes perforations in areas free of displays and conductor harnesses for facilitating folding of an original 2D substrate into a 3D structure. The 3D folded structures may be applied to keyboards to form dynamically changeable display keyboards.

Description

THREE-DIMENSIONAL DISPLAY MATRICES ON FLEXIBLE SUBSTRATES AND

METHODS FOR FABRICATING SAME

FIELD OF THE INVENTION The present invention relates generally to display matrices printed on flexible or on a combination of flexible and firm substrates, and more particularly to three-dimensional (3D) integrated display matrices and electrical harnesses (conductor) structures.

BACKGROUND OF THE INVENTION Display matrices, in which each display is addressable through respective electrical conductors are known. The individual display may be fabricated using a host of technologies including, but not limited to, liquid crystal display (LCD), organic light emitting diode (OLED), thin film transistor (TFT), or e-ink technologies. For example, US Patent No 6,498,592 discloses a display tile structure using organic light emitting materials fabricated on a single substrate. A method of fabricating large organic displays and conductors on flexible substrates is exemplarily disclosed in U.S. Patent No. 7,011,983. Control mechanisms for display matrices are exemplarily disclosed in U.S. Patent No. 6,798,359.

The use of displays for illuminating keyboards is known, see e.g. US patent No. 7,053,799 to Yu et al, 6,797,902 to Farage and 6,918,677 to Shipman. Key displays used dynamically, i.e. for exhibiting certain changeable symbols on a physical (mechanical) key are also known. Examples include IBM Technical Disclosure Bulletin (TDB) publications by P.G. Hebalkar, IBM TDB vol. 21, No. 5, Oct. 1978 and L. W. Hoevel et al, IBM TDB vol. 26, No. 9, pp. 4582-4583, Feb. 1984. hi particular, a conceptual drawing of computer keyboard with OLED dynamically changeable keys (named Optimus) has been recently disclosed by the Art Lebedev Studio, 5 Gazetny per. Moscow, Russia, 125993. Each key has its own tiny video screen in the form of a 32 x 32 pixel OLED display. Symbols on the keys can be changed to show different languages or symbols at a stroke. The methods for fabricating the OLED displays intended for use in this keyboard are not in the public domain. The prior art methods for forming display matrices are complicated, time-consuming and expensive. Typically, each display is fabricated and handled separately, then assembled with its respective electrical connectors. Further application to keyboards complicates the processing even more.

It would therefore be advantageous to have flexible integrated 3D display matrices and electrical conductors (the latter also referred to as "harnesses" or electrical "traces") that can be used in a variety of applications, specifically in keyboards. It would further be advantageous to have simple and inexpensive "batch" fabrication methods for making such

SUMMARY OF THE INVENTION

The present invention relates to integrated 3D display matrices-harness topologies (structures) on flexible or semi-flexible substrates and to methods for fabricating such structures. For simplicity, the term "flexible" in this description and claims refers both to truly flexible substrates, as well as to hybrid non-flexible/fiexible (or "partially flexible") substrates. The latter may include for example non-flexible areas that carry the displays. For simplicity, we will henceforth refer to all integrated structures of the present invention that combine display matrices and electrical harnesses on a single flexible substrate as "flexible 3D display matrices". More particularly, the present invention relates to efficient and low-cost processes for making flexible 3D display matrices that can be used in keyboards. As used herein, "keyboard" refers to any input device having keys, including computer keyboards, keypads, etc. The flexible 3D display matrices of the present invention include a plurality of components (displays, harnesses and optionally display drivers and associated electronics) formed on a single flexible substrate. The flexibility of the substrate allows a starting 2D "sheet" structure, which includes both display matrices and harnesses (and optionally display drivers and associated electronics) to be converted into a three-dimensional one. In one embodiment, the sheet is solid (without openings or "perforations"). In other embodiments the sheet is perforated, with sheet material removed from areas not having displays and harnesses.

The flexible 3D display matrices may be directly applied to a keyboard, turning its keys into dynamically changeable display keys. Both solid and perforated flexible 3D display matrices may be used for this purpose.

The invention is applicable to displays that can be fabricated by any display technology in or on flexible substrates. Exemplary substrates include (but are not limited to) polyimides such as Kapton®, polyesters such as Mylar and various laminated structures of these families of materials. While applicable to all types of displays as defined above, the invention is described in detail for OLED displays. "OLED" is meant to cover all type of organic LEDs, including (but not limited to) Active Matrix OLED (AMOLED), Passive Matrix OLED (PMOLED), Transparent Organic Light Emitting Device (TOLED), Flexible Organic Light Emitting Device (FOLED), Polymer LED (PLED) and Phosphorescent OLED (PHOLED™). Harnesses that include electrical conductors deposited on or embedded in a flexible substrate are well known and described for example in US Patent No. 6,939,737 (where they are called "electrical traces"). Another exemplary harness that can be printed with a conductive ink-jet printer is the "101-42 Electrically Conductive Ink" by Creative Materials, Inc. (141 Middlesex Road, Tyngsboro, MA 01879). The 101-42 product features excellent adhesion to Kapton®, Mylar, glass, Indium/Tin Oxide (ITO) sputtered surfaces and a variety of other surfaces. Its specification states that it is very resistant to flexing and creasing. Some applications for 101- 42 include, but are not limited to, EMI/RFI shielding of polyimide flexible circuits, polymer thick film circuitry, membrane switches, electrical attachments for surface mounted devices, bus-bars on ITO sputtered surfaces and anode coatings for tantalum capacitors.

According to the present invention there is provided a method for fabricating a flexible integrated display matrix-electrical harness structure including steps of: providing a 2D flexible substrate, forming a 2D integrated display matrix- harness structure on the flexible substrate and folding the 2D integrated display matrix - harness structure into a 3D matrix of displays - harness structure. Optionally, the integrated matrix of displays — electrical harness structure can be fabricated using roll-to-roll technologies (for example, as presented by VTT in Finland (Metallimiehenkuja 2, Espoo, P.O. Box 1000, FI-02044 VTT).

In some embodiments, the method further includes a step of: perforating the flexible substrate in substrate areas free of displays and harnesses. In alternative embodiments, the flexible substrate is perforated before the formation of the 2D integrated display matrix - harness structure on the flexible substrate.

In some embodiments, the folded 3D display matrix - harness structure is applied to a keyboard, thereby rendering the keyboard to be a dynamically changeable display keyboard.

According to the present invention there is provided a flexible 3D display matrix including a plurality of displays positioned substantially in a single plane on a flexible substrate and a plurality of flexible conductor harnesses for allowing addressing and control of each display, each harness extending at least partially into an out-of-plane direction relative to the single plane.

In some embodiments of the 3D display matrix, the flexible substrate includes perforations in areas free of displays and conductor harnesses. In some embodiments of the 3D display matrix, each display has a respective driver associated therewith, the driver positioned on the flexible substrate. hi some embodiments, the 3D display matrix is formed into a topology that matches a keyboard topology, whereby the display matrix is applied to the keyboard to form a display keyboard. In some embodiments of the 3D display matrix, each display is an OLED display.

According to the present invention there is provided a display keyboard including a plurality of keys arranged in a predetermined pattern on a 2D plane; and a flexible 3D display matrix adapted to match the predetermined key pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 shows a first embodiment of a 2D perforated integrated display - harness structure according to the present invention: a) top view; b) isomeric view; FIG. 2 shows the structure of FIG. 1 after folding into a perforated flexible 3D display matrix: a) top view; b) isomeric view;

FIG. 3 shows the perforated flexible 3D display matrix of FIG. 2 applied to a computer keyboard;

FIG. 4 shows the action of pressing a key of the display keyboard of FIG. 3; FIG. 5 shows a second embodiment of a 2D perforated integrated display - harness structure according to the present invention: a) top view; b) isomeric view;

FIG. 6 shows the structure of FIG. 5 after folding into a perforated flexible 3D display matrix: a) top view; b) isomeric view;

FIG. 7 shows the perforated flexible 3D display matrix of FIG. 6 applied to a computer keyboard;

FIG. 8 shows the action of pressing a key of the display keyboard of FIG. 7; FIG. 9 shows an embodiment of 2D non-perforated integrated display — harness structure according to the present invention;

FIG. 10 shows the structure of FIG. 9 after folding into a non-perforated flexible 3D display matrix: a) top view; b) isomeric view; FIG. 11 shows the non-perforated flexible 3D display matrix of FIG. 10, applied to a computer keyboard.

FIG. 12 shows the action of pressing a key of the display keyboard of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to flexible 3D display matrices and methods for fabricating same. In the following description, identical numerals used in different figures refer to the same elements. FIG. 1 shows in (a) a top view and in (b) isomeric view a 2D integrated display - harness structure 100 that includes a matrix of displays 102 coupled to harnesses 104 (connecting between displays) and 110 (connecting between displays and respective display controllers or other electronic elements, the latter two not shown) . The matrix of displays and harnesses are formed on (or in) a flexible polymer substrate (sheet) 106, using well known polymer electronics and display technologies, for example those developed at the Fraunhofer Institutes in Germany and the VTT roll-to-roll OLED manufacturing techniques mentioned above. In some embodiments, the substrate areas on which the displays are form may not be flexible. Areas 108 of the substrate that do not have displays or harnesses are removed, leaving a perforated substrate. As formed, structure 100 is two dimensional in a X-Y plane, with defined distances A, B between displays and C, D between harnesses 104.

The display, harness and substrate dimensions, both in thickness and in size are not drawn to scale and no limitation should be read into the dimensions shown. As well known, the active layers of displays (in particular OLEDs) are typically quite thin, on the order of a fraction of a micrometer, while harnesses may be one to two orders of magnitude thicker.

Each display includes a plurality of pixels (exemplarily 32x32 pixels). Each pixel is individually addressable electrically. The harness conductors are laid out and configured so as to enable this individual addressing. They may be made of any conducting material that can be deposited (sputtered, evaporated, deposited electrolessly or electrochemically from solution, ink-jet printed, etc.) or formed as a thin or thick film. Exemplary conductors that can be used include metals, conducting polymers or adhesives, conductive inks, carbon fibers, carbon nano- tubes and the like. Evidently, each display is individually addressable through its respective harnesses by a display driver and associated electronics (not shown), as well known in the art. The driver may be positioned adjacently to or remotely from its respective display. The fabrication of 2D structure 100 starts with a first step of depositing or otherwise forming together or separately the displays and harnesses on sheet 100. In a second, perforation step, sheet 100 is perforated by removing areas 108. The perforated display sheet structure (or simply "perforated structure") is still 2D at this stage. The perforations may be made by laser cutting, punching, stamping, abrading or any other material removal technique applicable to the substrate used. Obviously, the perforation step is performed while ensuring that no damage is caused to the displays or conductors. In alternative embodiments relevant to all the perforated structures disclosed herein, the perforated sheet may be prepared first, followed by the deposition of the displays and harnesses.

In a third, folding step, the perforated 2D structure is "folded" to achieve a perforated flexible 3D display matrix 200, as shown in FIG. 2a, b. The folding shrinks the in-plane (X-Y) distances between the displays to A', B' and between harnesses to C₉ D' and leads to the harnesses "hanging" in an out-of-plane direction relative to the X-Y plane. As shown, the out- of-plane direction is substantially the Z direction perpendicular to the X-Y plane. The harnesses are now "slack" and can accommodate significant Z-direction movements of the displays.

In an embodiment shown in FIG. 3, perforated flexible 3D display matrix 200 is applied to a computer keyboard 302. Each display 102 is structurally adapted to fit on a key 304 of the keyboard. Harnesses 104 are positioned between neighboring keys in a way such as to not interfere with the regular action of the key. Each display is secured to a key post 306, and covered with a translucent or transparent cap 308, so that the display is visible to a user. The caps are positioned in a way such as to prevent damage to the displays upon mechanical pressure. An elastic or rubbery layer 310 may be interposed between the display and the top of the key post in order to fixate the display to the key. Note that the folding used to form 3D perforated display sheet fulfills in this application two main purposes: a) to adapt the display pattern to that of the keyboard, and b) to allow the flexible harnesses to adapt to spacing limitations in a way that they allow unimpeded Z-direction movement of each key. FIG. 4 shows the action of pressing a key 304a of the keyboard. The typical Z - movement of a key may be of a few millimeters. The length of the harnesses is predetermined to be such as to allow this movement.

FIG. 5 shows in (a) a top view and in (b) isomeric view another 2D integrated display - harness structure, marked 500. Structure 500 is similar to structure 100, except that the harnesses are in the form of coils or serpentines 504 and 510. The width of a harness 504 is marked as L. An optional display driver 502 may be added to each display. Driver 502 may exemplarily be a display controller functioning as described in U.S. Patent No. 4,897,651. The incorporation of the driver and displays on a flexible substrate may follow the procedures used in the Osram Pictiva OLED display manufactured by Osram (Headquartered in Hellabrunner Strasse 1, 81543, Mϋnchen, Germany,)

The 2D display-harness structure is perforated and converted from a 2D structure into a perforated flexible 3D matrix of displays 600, see FIG. 6a, b, following similar steps to those explained re. structure 100. FIG. 7 shows a row of keys 704 of a display keyboard 700 in which each display of perforated flexible 3D display matrix 600 is structurally adapted to fit on a respective key. Harnesses 504 are now coiled a way that they do not interfere with the regular action of the key. As in FIG. 3, each display is secured to a key post through an elastic or rubbery layer and covered with a translucent or transparent cap so that the display is visible to a user and protected from mechanical damage.

FIG. 8 shows the action of pressing a key 704a of keyboard 700. The typical Z- movement of a key may be of a few millimeters. The length of the harnesses is predetermined to be such as to allow this movement

FIG. 9 shows a top view of yet another 2D integrated display - harness structure, marked 900. In contrast with the previous embodiments, structure 900 is not perforated. The fabrication starts with forming, in a first step, a 2D matrix of displays 102 along with harnesses

904, 910 on (or in) a flexible sheet 906. The sheet material has enough flexibility to be able to stretch and fold without damaging the harness conductors. In a second step, unlike in the first two embodiments, the 2D structure is folded by a mechanical process into a flexible 3D display matrix 1000 shown in FIG. 10a, b. Exemplarily, the process may be stamping or molding, and the resulting 3D structure may resemble that of an egg-carrier tray. FIG. 11 shows an embodiment of a display keyboard 1100, in which flexible 3D display matrix 1000 is applied to a computer keyboard 1102. Each display is structurally adapted to fit on a key 1104 of the keyboard. Harnesses 904 are now also lying between neighboring keys in a way that they do not interfere with the regular action of the key. An optional supporting ramp 1108 may be attached to the keyboard. Ramp 1108 isolates the mechanical action of pressing one key from affecting neighboring keys. As in FIGS. 3 and 7, each display is secured to a key post through an elastic or rubbery layer and covered with a translucent or transparent cap so that the display is visible to a user and protected from mechanical damage. FIG. 12 shows the action of pressing a key 1104a of keyboard 1102. The typical Z- movement of a key may be of a few millimeters. The length of the harnesses is predetermined to be such as to allow this movement

The invention has now been described with reference to specific embodiments. Other embodiments will be apparent to those of ordinary skill in the art. In particular, it is apparent that the displays, harnesses and associated drivers and electronics may be embedded in various layered polymeric substrates instead of being formed "on" such substrates. Various over-layers may be added in order to protect the displays and enhance their visibility.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A method for fabricating a flexible integrated display matrix-electrical harness structure, comprising steps of: a. providing a two dimensional (2D) flexible substrate; and b. forming a 2D integrated display matrix - harness structure on the flexible substrate.

2. The method of claim' 1 , further comprising a step of: c. perforating the flexible substrate in substrate areas free of displays and harnesses.

3. The method of claim I₅ further comprising a step of: c. folding the 2D integrated display matrix - harness structure into a three- dimensional 3D display matrix - harness structure.

4. The method of claim 1, wherein each display is an organic light emitting diode (OLED) display.

5. The method of claim 2, further comprising a step of: d. folding the 2D integrated display matrix - harness structure into a three- dimensional (3D) display matrix - harness structure.

6. The method of claim 2, wherein the step of perforating includes leaving un-perforated harness areas in the shape of coils.

7. The method of claim 5, wherein the step of folding includes i. shortening distances between displays while leaving the displays lying in essentially in an original 2D plane, and ii. having the harnesses extend into a direction perpendicular to the original 2D plane.

8. The method of claim 4, further comprising a step of applying title folded structure to a keyboard, thereby rendering the keyboard to be a dynamically changeable display keyboard.

9. The method of claim 5, further comprising a step of applying the folded structure to a keyboard, thereby rendering the keyboard to be a dynamically changeable display keyboard.

10. A flexible three-dimensional (3D) display matrix comprising: a. a plurality of displays positioned substantially in a single plane on a flexible substrate; and b. a plurality of flexible conductor harnesses for allowing addressing and control of each display, each harness extending at least partially into an out-of-plane direction relative to the single plane.

11. The 3D display matrix of claim 10, wherein the flexible substrate includes perforations in areas free of displays and conductor harnesses.

12. The 3D display matrix of claim 11, wherein each display has a respective driver associated therewith, the driver positioned on the flexible substrate.

13. The 3D display matrix of claim 10, formed into a topology that matches a keyboard topology, whereby the display matrix is applied to the keyboard to form a display keyboard.

14. The 3D display matrix of claim 11, formed into a topology that matches a keyboard topology, whereby the display matrix is applied to the keyboard to form a display keyboard.

15. The 3D display matrix of claim 12, formed into a topology that matches a keyboard topology, whereby the display matrix is applied to the keyboard to form a display keyboard.

16. The 3D matrix of displays of claim 10, wherein each display is an organic light emitting diode (OLED) display.

17. A display keyboard comprising: a. a plurality of keys arranged in a predetermined pattern on a two dimensional (2D) plane; and b. a flexible three-dimensional (3D) display matrix adapted to match the predetermined key pattern.

18. The display keyboard of claim 17, wherein the flexible 3D display matrix includes flexible conductor harnesses for allowing addressing and control of each display.

19. The display keyboard of claim 18, wherein the flexible 3D display matrix includes a plurality of displays positioned substantially in a single plane on a flexible substrate and wherein each harness extends at least partially into an out-of-plane direction relative to the single plane.

20. The display keyboard of claim 18, wherein the flexible substrate includes perforations in areas free of displays and conductor harnesses.