Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/001—Optical devices or arrangements for the control of light using movable or deformable optical elements based on interference in an adjustable optical cavity
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/004—Optical devices or arrangements for the control of light using movable or deformable optical elements based on a displacement or a deformation of a fluid
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
  • G06F3/016—Input arrangements with force or tactile feedback as computer generated output to the user
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
  • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
  • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
  • G06F3/0412—Digitisers structurally integrated in a display
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
  • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
  • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
  • G06F3/0414—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
  • H03K17/96—Touch switches
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
  • H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
  • H03K2217/96—Touch switches
  • H03K2217/96042—Touch switches with illumination
  • H03K2217/96046—Key-pad combined with display, back-lit

Definitions

• the present invention relates to display elements for visual and/or tactile displays, and particularly but not exclusively for touch-sensitive displays.
• LCD liquid crystal
• CRT CRT
• OLED/LED OLED/LED
• projection OLED
• Emissive technology such as plasma, CRT and OLED/LED that emits light at predefined positions on the screen to render the required image.
• a touch-sensitive layer may be added to the display panel to enable user input using fingers or styli.
• a tactile layer may be added that gives a textured or 3D representation.
• the additional layer and associated components add to the cost of the display.
• touch-sensitive technologies based on row and column sensing in a matrix are only able to detect a single touch at any one time.
• Other touch-sensitive technologies have poor spatial resolution.
• an electrically actuable display element according to claim 1 .
• a display element according to claim 14.
• Figure 1 is a schematic cross section of two adjacent pixels in respective non- actuated and actuated configurations, in a display panel according to the first embodiment of the invention.
• Figure 2 is a schematic perspective view of the layers of the display panel of the first embodiment.
• Figure 3 is a schematic cross section of two adjacent pixels in respective non-touch- sensitive and touch-sensitive configurations, in the display panel of the first embodiment.
• Figure 4 is a schematic cross section of two adjacent pixels in respective non-tactile and tactile configurations, in the display panel of the first embodiment.
• Figure 5 is a schematic cross section of two adjacent pixels in respective non- actuated and actuated configurations, in a display panel according to a second embodiment of the invention.
• a first embodiment of the present invention comprises a visual display screen with touch-sensitive input and tactile output.
• the visual, touch-sensitive and tactile functions are all provided by the same electrically active material, such as piezoelectric material.
• piezoelectric materials generate an electric field in response to mechanical stress and also exhibit the reverse piezoelectric effect, in which the application of an electric field produces stress in the material, resulting in expansion or contraction of the material if not constricted.
• the stress in the material may be proportional to the electric field.
• Piezoelectric materials may be ceramics or polymers such as PVDF.
• the mechanical and electrical properties of the piezoelectric material may be enhanced by providing several layers of the material.
• piezoelectric materials As an alternative to piezoelectric materials, other materials may be used which exhibit a shape or size change in response to an electric field, such as carbon nanotube materials currently proposed for use as artificial muscles (see for example 'Giant- Stroke, Superelastic Carbon Nanotube Aerogel Muscles', Aliev A et. al. Science 20 March 2009, VI. 323. no. 5921 , pp. 1575 - 1578).
• FIG. 1 to 4 illustrate the constructional details of a display panel according to a first embodiment of the present invention.
• the visual display screen of the first embodiment comprises an insulating substrate 1 carrying a matrix of cells 2a, 2b corresponding to the pixel configuration of the display.
• the cells 2a, 2b may be formed integrally as holes in the surface of the substrate 6, or applied as a separate perforated layer as shown in Figure 2. In either case, the cells 2a, 2b have walls 3 formed between them.
• a piezoelectric actuating element 4a, 4b is fitted in each of these cells 2a, 2b, leaving a small void at the top of the cell 2a, 2b.
• the insulating substrate 1 carries electrical connections 8a, 8b, for example as a layer formed on one or both sides thereof, which make an independently addressable electrical connection to each piezoelectric actuating element 4a, 4b.
• a display controller 10 is connected to the electrical connections, to drive the display as described in more detail below.
• the upper surface 5a, 5b of each piezoelectric actuating element 4a, 4b is arranged to reflect and/or emit light when illuminated, according to the desired appearance of the corresponding pixel when switched on.
• the upper surface 5a, 5b comprises a coloured layer having the desired colour of that pixel.
• the coloured layer may be fluorescent.
• each cell 2a, 2b is filled with a substantially opaque fluid 6, and the cells 2a, 2b are sealed by a substantially transparent front screen 7, fixed to the top ends of the walls 3.
• the fluid 6 fills the void above piezoelectric actuating element 4a and obscures the upper surface 5a of the piezoelectric actuating element 4a, so that only the fluid 6 is visible through the front screen 7.
• the piezoelectric actuating element 4b expands in height and contracts in width when a voltage Vi is applied across it, so that the liquid 6 is expelled from between the upper surface of the piezoelectric actuating element 4b and the front screen 7, and is retained between the walls 3 and the sides of the piezoelectric actuating element 4b.
• the upper surface is now visible through the front screen and the pixel appears in its On' state.
• the piezoelectric actuating element returns to its rest position as shown in cell 2a.
• the intensity of the displayed pixel may be controlled by varying the voltage V
• the upper surface 5a, 5b is fluorescent, it may be illuminated by ultraviolet (UV) light from a light source forming part of the display screen.
• UV light may be introduced into one or more sides of the front screen 7, which acts as a light guide for the UV light.
• One pole 8a of the electrical connection to the piezoelectric actuating element 4a, 4b may be made via the fluid 6, which is electrically conductive, for example by including a dissolved salt.
• a touch-sensitive function of the display of the first embodiment is illustrated in Figure 3.
• the front screen 7 is flexible, so that pressure applied to the front screen 7 is transmitted to the piezoelectric actuating element 4b.
• a voltage V 2 is produced across the electrical connections 8a and 8b and is sensed by the display controller 10, which detects in which individual cells 2a, 2b pressure is applied. Since the detected voltage varies with pressure, the display controller 10 may determine the level of pressure applied to each pixel, thereby enabling a proportional touch-sensitive display.
• Each pixel effectively acts as a display element and individually addressable pressure transducer. This technology enables many new touch-sensitive display applications.
• the piezoelectric actuating element 4b is energised by applying the voltage Vi
• the voltage V 2 will oppose the applied voltage V(.
• the spacing between the upper surface 5a in the Off state and the front screen 7 may be such that pressure cannot be sensed by the piezoelectric actuating element 4a in its 'off state.
• FIG. 4 A tactile aspect of the first embodiment is illustrated in Figure 4. If a voltage V 3 higher than voltage V
• the first embodiment provides visual, touch-sensitive and/or tactile functions by means of the same piezoelectric element, and the need for additional layers for touch- sensitive and/or tactile functions is avoided. It is not essential that all three of these functions be provided; for example, if the front screen 7 is rigid, only the visual display will be provided.
• the piezoelectric elements 4a, 4b may comprise stacked multiple layers of piezoelectric material.
• the piezoelectric elements 4a, 4b may be arranged in a cantilever bending or beam configuration.
• the piezoelectric elements 4a, 4b may be arranged in an X- poled or Y-poled configuration.
• the display panel may be used as an interactive indicator, point of sale display or other display.
• the applications of the first embodiment are not limited to flat display screens, but may include for example a 'skin' or surface layer for toys and other products, enhancing the user experience with two way visual and tactile communication between the product and the user.
• the visual and/or tactile display function is provided by electrically heated thermal expansion rather than piezoelectricity.
• piezoelectric elements may be included for touch-sensitivity. Similar parts to those of the first embodiment are shown with the same reference numerals and their description is not repeated, for brevity.
• each cell 2a, 2b is provided a thermally expanding sac 1 1a, l ib containing a fluid that is selectively heated by supply of current to an electric heater 9a, 9b under the control of the display controller 10.
• the upper surface 5a, 5b is thereby forced upwards into proximity or contact with the front screen 7 and becomes visible, and the pixel is switched On'.
• the sac 1 1 a, l ib contracts and the pixel is switched Off .
• the display controller 10 may independently switch each pixel on and off.
• the upper surface 5a, 5b may be flexible, so that the proportion of the upper surface 5a, 5b in contact with the front screen 7 increases as the sac 1 1 a, l ib expands. In this way, the intensity of the displayed colour of the pixel may be controlled.
• the front screen 7 may be flexible, and may be distorted outwardly by the expansion of the sac 1 1a, l ib, thereby providing a tactile representation of the pixel when switched On'.
• a piezoelectric sensing element 4a, 4b may be provided within the each sac 1 1 a, 1 lb, and the front screen 7 may be flexible.
• the front screen 7 may be flexible.
• pressure applied to the front screen 7 is hydraulically transferred to the piezoelectric sensing element 4a, 4b, which generates a voltage that is sensed by the display controller 10 and therefore provides independent touch sensitivity for each cell 2a, 2b.
• Alternative electrically actuated means may be provided within each cell 2a, 2b to provide a similar effect to the piezoelectric elements 4a, 4b and/or the thermally expanding sacs H a, l ib.
• micromechanical actuators may be used.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Human Computer Interaction (AREA)
• Optics & Photonics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Position Input By Displaying (AREA)
• Devices For Indicating Variable Information By Combining Individual Elements (AREA)
• Mechanical Light Control Or Optical Switches (AREA)
• Push-Button Switches (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (1)

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Citations (3)

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• 2010
  • 2010-02-22 EP EP10275021.3A patent/EP2360507B1/en active Active
• 2011
  • 2011-02-22 CN CN2011800199787A patent/CN102959453A/zh active Pending
  • 2011-02-22 KR KR1020127024588A patent/KR101651913B1/ko not_active Expired - Fee Related
  • 2011-02-22 WO PCT/GB2011/000243 patent/WO2011101649A1/en not_active Ceased
  • 2011-02-22 US US13/583,200 patent/US9710091B2/en not_active Expired - Fee Related
  • 2011-02-22 JP JP2012553400A patent/JP5763685B2/ja not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (1)

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