Title:
ELECTROMAGNETIC-WAVE MODULATING, MOVABLE ELECTRODE, CAPACITOR ELEMENTS
Document Type and Number:
WIPO Patent Application WO/1993/024922
Kind Code:
A1
Abstract:
Electromagnetic-wave-modulating capacitors (10) having transparent movable electrodes (20, 22, 24, 26) and conductive fixed electrodes (14) are low-cost, low-energy, reliable and fast-acting elements for employment in highly transparent applications, such as in reflective display pixels for large and small-scale video displays, including full-color displays where multiple such capacitors are aligned in a single pixel. Further embodiments, not necessarily with a transparent electrode, are assemblable into arrays antennas deployable in outer space; provide digitally controllable or responsive such variable capacitors; and in mechanically active applications can be constituted as accelerometers, or in microrobotics. Constructions with ultra-thin electrodes have special advantage.
Inventors:
KALT CHARLES G (US)
SLATER MARK S (US)
SLATER MARK S (US)
Application Number:
PCT/US1993/005234
Publication Date:
December 09, 1993
Filing Date:
May 24, 1993
Export Citation:
Assignee:
KALT CHARLES G (US)
SLATER MARK S (US)
SLATER MARK S (US)
International Classes:
G02B26/08; G09F9/37; H01G5/04; G09F13/04; (IPC1-7): G09G3/34; G09G3/16; H01G7/00; H01G7/06
Foreign References:
| US3989357A | 1976-11-02 | |||
| US4266339A | 1981-05-12 | |||
| US4786149A | 1988-11-22 | |||
| US5233459A | 1993-08-03 | |||
| US4094590A | 1978-06-13 | |||
| US4736202A | 1988-04-05 | |||
| US4704707A | 1987-11-03 |
Other References:
See also references of EP 0646269A4
Download PDF:
Claims:
Claims
| 1. | A reflective display pixel for a reflective display constituted by a matrix of said reflective display pixels, said reflective display pixel having: i) a reflectancecontrolled pixel area extending across a light path to a viewer; ii) a lightmodulating capacitor comprising: a) a transparent dielectric member having opposed faces and extending across and throughout said pixel area; c) an active, lightmodulating electrode movable to and from a position extending into said pixel area on the other face of said dielectric member; said active, lightmodulating electrode being movable in response to changes in an electric potential difference applied between said active movable electrode and said transparent electrode to extend across said light path and modulate light traveling therealong; said reflective display pixel being characterized by said lightmodulating capacitor further comprising: b) a transparent electrode extending across one face of said dielectric member throughout said display area, said transparent electrode having a light transmissivity of at least 80 percent and a conductivity expressed as a resistivity of not more than 100 ohms per square; and said reflective display pixel comprises: iii) reflectance means extending across said light path in said pixel area on an opposite side of said light modulating capacitor remote from said viewer said reflectance means being visually related to said lightmodulating active movable electrode for reflectance control of said pixel area; wherein the appearance of said pixel area to said viewer can be selectively comprised by said lightmodulating electrode in combination with said reflectance means, and wherein light reflected from said reflectance means traverses said transparent electrode two times, traveling therethrough on both an incident and a reflected path. |
| 2. | A reflective display pixel as claimed in Claim 1 characterized in that said reflectance means comprises a reflective background and a second said lightmodulating capacitor having a second active, lightmodulating electrode movable to extend across said light path, said second active movable electrode and said background being cooperative to provide a variable reflectance, wherein said first and second active, lightmodulating movable electrodes and said background have different visual characteristics one from another whereby said appearance of said pixel area can be selectively composed from said first and second active, lightmodulating movable electrodes and said background. |
| 3. | A reflective display pixel as claimed in Claim 2 characterized by further comprising a sheetlike, transparent substrate having one and another opposed substrate surfaces extending across said light path and supporting said first lightmodulating capacitor to extend across one substrate surface and said second light modulating capacitor to extend across said other substrate surface. |
| 4. | A reflective display pixel as claimed in Claim 2 characterized in that each said light modulating capacitor has a plurality of active, movable, lightmodulating electrodes selectively movable to traverse said pixel area in response to applied electric potential differences. |
| 5. | A reflective display pixel as claimed in Claim 4 characterized in that each said active movable electrode comprises a flexible plastic leaf having an anchored portion and a movable portion extensible across said pixel area, said plastic leaf having a metallized surface engageable with said dielectric member. |
| 6. | A reflective display pixel as claimed in Claim 1 characterized in that said active movable electrode is tapered in its direction of movement to be displaceable, in a voltage controlled manner, by a distance related to the applied voltage. |
| 7. | A reflective display pixel as claimed in Claim 1 characterized in that said transparent electrode comprises indium tin oxide. |
| 8. | A reflective display pixel as claimed in Claim 3 characterized by further comprising third and fourth said movable active electrode lightmodulating capacitors disposed on said opposed surfaces of said transparent substrate to share said pixel area respectively with said first and said second active, movable electrodes. |
| 9. | A reflective display pixel as claimed in Claim 8 characterized by further comprising active electrodes which are activatable selectively to display selected intensities of the achromatic colors black and white and three primary, chromatic, mixing colors. |
| 10. | A reflective display pixel as claimed in Claim 1 characterized in that said fixed electrode light transmissivity is at least 90% and said conductivity is expressed as a resistivity of no more than 70 ohms per square. |
| 11. | A generally flat, electronically driven, fullcolor moving video screen characterized by comprising a matrix of reflective display pixels, each said pixel being as claimed in claim 9. |
| 12. | A generally flat, electronically driven, monochrome moving video screen characterized by comprising a matrix of reflective display pixels, each said pixel being as claimed in claim 1. |
| 13. | A lightmodulating capacitor capable of displaying at least three visually distinct color states each said color state being selected from chromatic and achromatic colors, said capacitor comprising a plurality of capacitor elements each capacitor element comprising: a) a laminar translucent dielectric member having opposed first and second surfaces; b) a fixed electrode engaged with one of said surfaces; and c) a movable lightmodulating electrode; said capacitor being constructed, arranged and adapted to operate for each said movable lightmodulating element to be selectively movable into engagement with the other of said surfaces of said dielectric member in response to a potential difference between said movable electrode and a respective fixed electrode and to be retracted in the absence of said potential difference, characterized by each said element being adapted to modulate light striking said dielectric member; and d) a further lightmodulating element cooperative with said movable lightmodulating elements and capable of modulating light transmitted through said dielectric member; each said light modulating element displaying one of said visually distinct states. |
| 14. | A lightmodulating capacitor as claimed in Claim 13 characterized by further comprising a sheetlike, transparent substrate having one and another opposed substrate surfaces extending across said light path and supporting said first lightmodulating capacitor to extend across one substrate surface and said second light modulating capacitor to extend across said other substrate surface. |
| 15. | A reflective display pixel as claimed in Claim 14 characterized in that each said active movable electrode comprises a flexible plastic leaf having an anchored portion and a movable portion extensible across said pixel area, said plastic leaf having a metallized surface engageable with said dielectric member. |
| 16. | A reflective display pixel as claimed in Claim 14 characterized in that said active movable electrode is tapered in its direction of movement to be displaceable, in a voltage controlled manner, by a distance related to the applied voltage. |
| 17. | A reflective display pixel as claimed in Claim 13 characterized in that said transparent electrode comprises indium tin oxide. |
| 18. | A reflective display pixel as claimed in Claim 14 characterized by further comprising third and fourth said movable active electrode lightmodulating capacitors disposed on said opposed surfaces of said transparent substrate to share said pixel area respectively with said first and said second active, movable electrodes. |
| 19. | A reflective display pixel as claimed in Claim 18 characterized by further comprising active electrodes which are activatable selectively to display selected intensities of the achromatic colors black and white and three primary, chromatic, mixing colors. |
| 20. | A digitally responsive, electromagneticwave modulating capacitor comprising a movable active electrode, a dielectric member and a control electrode, said capacitor having an active condition in which said electrodes and said dielectric member are held in capacitative, laminar engagement by electrostatic attraction generated by a potential difference applied between said electrodes in a manner enabling said capacitor to extend across an electromagnetic wave path and modulate said electromagnetic wave and having a relaxed condition in which said potential difference is not applied, said movable electrode is retracted away from said electromagnetic wave path and said electromagnetic wave is not so modulated, characterized in that at least one of said electrodes has at least one lateral edge which is stepped to taper in a direction away from said retracted position to be digitally responsive to changes in said applied potential difference. |
| 21. | A digitally responsive, electromagneticwave modulating capacitor according to claim 20 characterized in that said control electrode is fixed and has a pair of symmetrically disposed stepped lateral edges tapering in said direction away from said retracted position. |
| 22. | A lowcost, sensitive, reliable accelerometer for sensing acceleration and providing an electrical output, said accelerometer being characterized by comprising a variable capacitative element having: a) a laminar dielectric member having opposed first and second surfaces; b) a control electrode capacitatively engaged with said first dielectric member surface in activated condition of said capacitative element; and c) an active, movable, electrode, having a conductor surface capacitatively engageable with said second dielectric member surface in response to an activation potential difference applied between said electrodes; said accelerometer being disposed in a movable or moving system to sense acceleration of said system, and being coupled in electric circuit to provide a control output responsive to a desired acceleration. |
| 23. | An accelerometer according to claim 22, for activating an automobile airbag, comprising at least two pairs of said variable capacitative elements mounted for movement in opposed directions along an axis, said pairs of variable capacitative elements being mounted approximately orthogonally in a plane including an intended direction of travel of said automobile, said accelerometer including an oscillator circuit coupled with said variable capacitance elements to sense capacitances changes produced by acceleration and provide a control output. |
| 24. | A variable capacitative element comprising: a) a laminar dielectric member having opposed first and second surfaces; b) a control electrode capacitatively engaged with said first dielectric member surface in activated condition of said capacitative element; and c) an active, movable, electrode, having a conductor surface capacitatively engageable with said second dielectric member surface in response to an activation potential difference applied between said electrodes; said active, movable electrode being selectively movable between an extended position for electromagnetic wave modulation and a retracted position and being formed of a flexible plastic material having a thin, metallized conductor surface, being said surface capacitatively engageable with said dielectric member, said active movable electrode being prestressed to adopt said retracted position in a relaxed state, characterized by having a thickness not exceeding about 2 microns. |
| 25. | A variable capacitative element according to claim 24 characterized in that said movable electrode is a metallized plastic film heattreated to form a coil, said metallized conductor surface being outwardly, convexly exposed from said coil for engagement with said dielectric member. |
| 26. | A method of manufacturing a video display matrixed from a plurality of lightmodulating, capacitative pixels each having a lightmodulating, movable active electrode, said method comprising: a) assembling a plurality of sheetlike layered materials into a laminated structure, said sheetlike layered materials including: i) a fixed electrode layer; ii) a dielectric layer capacitatively engaging said dielectric layer; and iii) an active, lightmodulating, movable electrode layer having a plurality of adjacent, active electrodes each said active, movable electrode being prestressed to adopt a retracted, inactive configuration, said active movable electrodes being advanceable from said retracted position by application of a potential difference between said fixed electrode and said metallization; and: b) forming said active, lightmodulating, movable electrode layer from a sheet of metallized plastic material supported on said laminated structure with said metallization toward said structure and said plastic material exposed outwardly, said method being characterized by said forming step b) comprising: iv) cutting partial outlines of said movable electrodes in said metallized plastic sheet in a pattern providing a movable portion and a fixed portion of each said active, movable electrode, said cutting being only a partial incision along the cut outline, whereby the movable electrode portions of said sheet remains in place during said cutting step, and said cut outlines including a common outline between adjacent movable electrode portions, ; and v) curing said laminated structure with said metallized plastic sheet bearing said cut electrode outlines exposed outwardly to be heated, in an oven to cause said plastic material in said movable electrode portions to shrink and break away along said outlines; whereby, on cooling, said movable electrodes adopt said retracted configuration. |
| 27. | A method of manufacturing a video display according to claim 26 further characterized by comprising: c) applying an electrically conductive adhesive to said dielectric layer in predetermined areas for secural of said fixed portions of said active movable electrodes; and d) securing said sheet of metallized plastic material to said dielectric by means of said adhesive areas, said adhesive areas being registered with said fixed active movable electrode portions. |
Description:
International Bureau
INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
(51) International Patent Classification 5 : (11) International Publication Number: WO 93/2492
G09G 3/34, 3/16, H01G 7/00 Al H01G 7/06 (43) International Publication Date : 9 December 1993 (09.12.9
(21) International Application Number: PCT/US93/05234 (81) Designated States: CA, JP, European patent (AT, B CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, N
(22) International Filing Date: 24 May 1993 (24.05.93) PT, SE).
Published
(30) Priority data: With international search report.
07/887,714 22 May 1992 (22.05.92) US With amended claims.
Date of publication of the amended claims:
(71)(72) Applicants and Inventors: KALT, Charles, G. [US/US]; 17 February 1994 (17.02.9 P.O. Box 72, North Adams, MA 01247 (US). SLATER, Mark, S. [US/US]; 510 North Houghton Street, Clarks¬ burg, MA 01247 (US).
(74) Agent: HANDAL, Anthony, H. ; Handal & Morofsky, 80 Washington Street, Norwalk, CT 06854 (US).
(54) Title: ELECTROMAGNETIC- WAVE MODULATING, MOVABLE ELECTRODE, CAPACITOR ELEMENTS
(57) Abstract
Electromagnetic- wave-modulating capacitors (10) having transparent movable electrodes (20, 22, 24, 26) and conductiv fixed electrodes (14) are low-cost, low-energy, reliable and fast-acting elements for employment in highly transparent applica tions, such as in reflective display pixels for large and small-scale video displays, including full-color displays where multipl such capacitors are aligned in a single pixel. Further embodiments, not necessarily with a transparent electrode, are assemblabl into arrays antennas deployable in outer space; provide digitally controllable or responsive such variable capacitors; and in me chanically active applications can be constituted as accelerometers, or in microrobotics. Constructions with ultra-thin electrode have special advantage.
: (Referred to in PCT Gazette No. 09/1994, Section II