WO2005071644A1 - Ecran a feuille - Google Patents

Ecran a feuille Download PDF

Info

Publication number
WO2005071644A1
WO2005071644A1 PCT/IB2005/050206 IB2005050206W WO2005071644A1 WO 2005071644 A1 WO2005071644 A1 WO 2005071644A1 IB 2005050206 W IB2005050206 W IB 2005050206W WO 2005071644 A1 WO2005071644 A1 WO 2005071644A1
Authority
WO
WIPO (PCT)
Prior art keywords
flexible element
light
display device
front plate
foil display
Prior art date
Application number
PCT/IB2005/050206
Other languages
English (en)
Inventor
Johannes Marra
Original Assignee
Koninklijke Philips Electronics N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2005071644A1 publication Critical patent/WO2005071644A1/fr

Links

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/37—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being movable elements
    • G09F9/372—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being movable elements the positions of the elements being controlled by the application of an electric field

Definitions

  • the present invention relates to a dynamic foil display according to the preamble of claim 1.
  • a conventional emissive foil display comprises a light guide in the form of an edge-lit glass plate, also known as a light guide plate, an active plate, or a back plate. It also comprises a non-lit front plate, also known as a passive plate.
  • a light-scattering foil also known as a flexible element, is clamped in between spacer elements disposed on these plates. The distribution of the spacer elements across the plates defines the size and location of the individual picture elements (pixels) of the foil display.
  • a foil electrode layer is disposed on at least one side of the light-scattering foil for the purpose of enabling the application of a substantially uniform voltage to the foil, thereby making the foil electrode to serve as a common display electrode.
  • both plates there are respective sets of parallel electrodes which are arranged perpendicularly with respect to each other such as to constitute a set of row electrodes on the front plate and a set of column electrodes on the light guide plate.
  • suitable voltages to the foil electrode and to appropriate electrodes on the light guide plate and the front plate it is possible to generate two opposing electrostatic forces onto the foil with the force vectors directed towards the light guide plate and towards the front plate, respectively.
  • the balancing of these two opposing electrostatic forces in combination with the elastic force existing in the foil is used to attract a portion of the foil associated with a single picture element towards either the light guide plate or towards the front plate.
  • the foil can be locally attracted towards the light guide plate by applying a larger voltage difference between the foil electrode and the local column electrode on the light guide than between the foil electrode and the local row electrode on the front plate.
  • the foil can be locally attracted towards the front plate by applying a larger voltage difference between the foil electrode and the local row electrode on the front plate than between the foil electrode and the local column electrode on the light guide plate.
  • a dynamic foil display of this general emissive type is known from WO00/38163.
  • a dynamic foil display with reflective properties instead of emissive.
  • This provides a reflective dynamic foil display comprising a plurality of localised picture elements that either reflect or absorb the ambient light that is incident upon the respective localised picture elements of the display.
  • a reflective foil display does not rely on the presence of a light guide plate or on light sources that couple light into the light guide. Instead, only a thin back plate and the presence of ambient light suffice.
  • a reflective foil display can therefore be made thinner and reduced in weight, and consumes significantly less electrical power than an emissive foil display. The latter characteristics enhance the portability of the display, allow more design freedom for creating a flexible display, and increase the applicability of the display under a variety of circumstances.
  • the flexible element comprises a light- reflecting layer. This has the effect that when a portion of the flexible element associated with a single picture element is in local contact with the front plate, the incoming light through the front plate is locally reflected back towards a viewer by virtue of this light- reflecting layer, and the portion appears illuminated to the viewer, thereby creating a bright picture element.
  • the illuminated portion appears bright-white in case no light-absorbing materials and/or colour filters are present in the path of the incoming and reflected light.
  • the illuminated portion appears coloured in case a colour filter is present in the path of the incoming light.
  • the colour filter may be disposed on either the side of front plate facing the flexible element or on the side of the flexible element facing the front plate.
  • an absorptive non-scattering colour filter comprising a two-dimensional geometrical pattern of red, green and blue patches, the size of the patches corresponding with the size of the picture elements of the reflective foil display.
  • the flexible element By omitting the incorporation of light-scattering means in the flexible element and by substantially avoiding the presence of light-scattering means in the path of the incoming and reflected light, and by using a flexible element that comprises a specular- reflective light-reflecting layer, the locally reflected light from the flexible element becomes mirror-reflective.
  • the inventive foil display can then be locally or entirely turned into a mirror by allowing mirror reflection of incident light to occur from all locally-present picture elements or from all display picture elements, respectively.
  • the flexible element is preferably surrounded by an essentially electrically-insulating light-absorbing fluid. This allows electric fields to be applied across the fluid and creates good optical contrast properties.
  • the light-absorbing fluid can comprise a dark-coloured dye that either constitutes the fluid or that is dissolved in the fluid. This is a simple and efficient way of providing a dark-coloured light-absorbing fluid.
  • this solution can either be combined with or exchanged for a solution where the light-absorbing fluid comprises substantially non-scattering dark-coloured pigment particles. This also has the above advantages of simply and efficiently providing a dark-coloured light-absorbing fluid.
  • the light-absorbing fluid comprises dark-coloured pigment particles
  • these particles preferably have a diameter of approximately 5 - 50 nm, which gives a substantially non-scattering fluid with good light-absorbing properties.
  • Preferred dark-coloured pigment particles comprise carbon-black particles.
  • the flexible element is preferably fluid pervious, which makes it possible for the fluid to travel through the flexible element when portions thereof are moved into and out of contact with the front plate and the back plate, respectively. This gives the advantage that the fluid can quickly move from one side of the flexible element to the other and, thus, that local portions of the flexible element can be switched quickly into and out of contact with the front plate.
  • the pervious property of the flexible element is preferably obtained by way of providing pores in the flexible element. This is a simple and efficient manner of providing a fluid pervious flexible element.
  • the pores preferably have a diameter of at least 0.5 ⁇ m and are preferably present at a volume density that constitutes at least 0.5% of the volume of the flexible element so that the above mentioned particles do not clog the pores and that the fluid can easily flow through the flexible element.
  • the pores are preferably straight which further enhances the above advantages of an efficient and fast fluid flow through the flexible element so that a fast switching of the individual picture elements can be accomplished.
  • the light-reflecting layer is preferably arranged on the side of the flexible element facing away from the front plate. This provides efficient back-reflection and scattering of the reflected light towards a display viewer by the light-scattering means provided to the flexible element.
  • the light-reflecting layer preferably comprises a coating of aluminium which is an inexpensive and simple way of providing good reflective properties.
  • a specular- reflective coating of aluminium disposed on the flexible element allows the inventive foil display to be used as a mirror display.
  • the light-reflecting coating of aluminium on the flexible element also comprises the flexible element electrode with which an electric potential can be applied to the flexible element.
  • Fig. 1 is a schematic cross-sectional view of a prior art display device
  • Fig. 2 is a schematic plan view of a display device according to the invention
  • Fig. 3a is a schematic cross-sectional view of a portion of the display in a first state
  • Fig. 3b is a schematic cross-sectional view of the portion in Fig. 1 in a second state
  • Fig 4 is a cross-sectional, perspective, enlarged view of a flexible element.
  • the display device 1 comprises a front plate 2, a flexible element or light-scattering foil 3 and a back plate 4.
  • Electrode systems 5 and 6 are arranged, respectively, on the surfaces of the front plate 2 and the back plate 4 facing the flexible element 3.
  • the electrodes 5 and 6 form two perpendicularly-oriented sets of electrodes which cross each other at an angle of preferably 90°, c.f. Fig. 2.
  • Picture elements are present at each crossing of the electrodes 5 and 6 and are laterally bounded by adjacent spacer elements 11 disposed on each of the plates 2 and 4.
  • the electrodes 5 and 6 form a passive matrix structure.
  • selection signals electrical voltages
  • This set of selection signals determines the set of potentials on the electrodes 5 and 6. Furthermore, a separate voltage is applied to the flexible element 3.
  • the flexible element 3 can be actuated, in operation, to move towards and away from the electrodes 5 and
  • Electrodes 5 form column electrodes, i.e. electrodes extending in the "short" direction of a rectangular display, while electrodes 6 form the row or line electrodes, i.e. electrodes extending in the "long" direction of such a display.
  • the flexible element 3 is provided with a light-reflecting coating 7, preferably of aluminium, which also serves as a flexible element electrode, on the side of the flexible element facing away from the front plate 2. Further, referring to Fig.
  • the flexible element 3 is surrounded by a dark-coloured, light-absorbing, electrically insulating fluid 8.
  • the fluid 8 can be obtained by composing it from at least one electrically insulating dark-coloured dye, by dissolving at least one dark-coloured dye in the fluid 8 and/or by dispersing e.g. 5 - 50 nm-sized, non-scattering dark-coloured pigment particles, for instance carbon-black particles of high jetness, in the liquid 8.
  • the fluid 8 must be electrically insulating in nature in order to allow electric fields to be imposed across the fluid with which the flexible element 3 can be moved either to or from contact with the plates 2 and/or 4, respectively.
  • the flexible element 3 is pervious to the dark-coloured fluid 8.
  • the flexible element 3 is provided with pores 9, c.f. Fig. 4.
  • the pores 9 enable the fluid 8 to flow through the flexible element 3 and quickly be moved from one side of the flexible element 3 to the other side as the flexible element 3 moves from the front plate 2 to the back plate 4 and vice versa under influence of the voltages imposed on the electrodes 5 and 6 and on the flexible element electrode (the reflective layer) 7.
  • the pores 9 in the flexible element 3 should have a diameter of at least 0.5 ⁇ m so that the above described carbon-black particles or any aggregates of these do not clog the pores 9.
  • the pores 9 are preferably straight and are preferably present at a volume density that constitutes at least 0.5% of the volume of the flexible element 3 so that the fluid 8 can easily flow through them from one side of the flexible element 3 to the other side of the flexible element 3.
  • straight is in this case meant that the pores 9 extend through the flexible element substantially perpendicularly to the surface of the foil, as is shown in Fig. 4, which is a cross-sectional, perspective view of the pores 9 in the flexible element 3.
  • Fig. 3 a the shown portion of the flexible element 3 is associated with a single picture element of the inventive dynamic foil display and is in a first state in contact with the back plate 4.
  • a maximum amount of dark-coloured fluid 8 is present between the flexible element 3 and the front plate 2.
  • a light ray 10 incident on the front plate 2 traverses the front plate 2 and is absorbed in the light-absorbing fluid 8.
  • a display viewer observing the front plate 2 sees the picture element associated with the portion of the flexible element 3 depicted in Fig. 3a as dark, as substantially no light is able to escape from this picture element of the dynamic foil display and can therefore not reach the eye of the display viewer.
  • the shown portion of the flexible element 3 is associated with a single picture element of the inventive dynamic foil display and is now in a second state in which it is in contact with the front plate 2.
  • a minimum amount, if any, of fluid 8 is in this case present between the flexible element 3 and the front plate 2.
  • a dynamic foil display device comprises a back plate (4), a front plate (2), a flexible element (3).
  • Row and column electrode means (5, 6) are arranged to bring one or more portions of the flexible element (3) either in contact with the front plate (2) or out of contact with the front plate (2).
  • the flexible element (3) comprises a light-reflecting layer (7).

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

L'invention concerne un écran à feuille dynamique comportant une plaque arrière (4), une plaque avant (2) et un élément flexible (3). Des éléments d'électrodes en rangées et colonnes (5, 6) sont conçus pour amener une ou plusieurs parties de l'élément flexible (3) en contact avec la plaque avant (2) ou hors contact avec la plaque avant (2). L'élément flexible (3) comporte une couche réfléchissant la lumière (7). Ainsi, de la lumière entrante est réfléchie par des parties de l'écran dans lesquelles l'élément flexible est en contact avec la plaque avant.
PCT/IB2005/050206 2004-01-21 2005-01-18 Ecran a feuille WO2005071644A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP04100171 2004-01-21
EP04100171.0 2004-01-21

Publications (1)

Publication Number Publication Date
WO2005071644A1 true WO2005071644A1 (fr) 2005-08-04

Family

ID=34802661

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2005/050206 WO2005071644A1 (fr) 2004-01-21 2005-01-18 Ecran a feuille

Country Status (2)

Country Link
TW (1) TW200539074A (fr)
WO (1) WO2005071644A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0007885A1 (fr) * 1978-05-18 1980-02-06 Battelle Memorial Institute Dispositif d'affichage sélectif d'une pluralité d'informations et son procédé de fabrication
US4729636A (en) * 1984-07-12 1988-03-08 U.S. Philips Corporation Passive display device having movable electrodes and method of manufacturing
US20020000959A1 (en) * 1998-10-08 2002-01-03 International Business Machines Corporation Micromechanical displays and fabrication method
EP1220190A2 (fr) * 2000-12-27 2002-07-03 Ngk Insulators, Ltd. Dispositif d'affichage réfléchissant

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0007885A1 (fr) * 1978-05-18 1980-02-06 Battelle Memorial Institute Dispositif d'affichage sélectif d'une pluralité d'informations et son procédé de fabrication
US4729636A (en) * 1984-07-12 1988-03-08 U.S. Philips Corporation Passive display device having movable electrodes and method of manufacturing
US20020000959A1 (en) * 1998-10-08 2002-01-03 International Business Machines Corporation Micromechanical displays and fabrication method
EP1220190A2 (fr) * 2000-12-27 2002-07-03 Ngk Insulators, Ltd. Dispositif d'affichage réfléchissant

Also Published As

Publication number Publication date
TW200539074A (en) 2005-12-01

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