GB2285518A - Sheet-like light guide for illuminating keypad - Google Patents

Sheet-like light guide for illuminating keypad Download PDF

Info

Publication number
GB2285518A
GB2285518A GB9500773A GB9500773A GB2285518A GB 2285518 A GB2285518 A GB 2285518A GB 9500773 A GB9500773 A GB 9500773A GB 9500773 A GB9500773 A GB 9500773A GB 2285518 A GB2285518 A GB 2285518A
Authority
GB
United Kingdom
Prior art keywords
light
light guide
keys
display
control panel
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
GB9500773A
Other versions
GB9500773D0 (en
GB2285518B (en
Inventor
Seppo Pienimaa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Oyj
Original Assignee
Nokia Mobile Phones Ltd
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 Nokia Mobile Phones Ltd filed Critical Nokia Mobile Phones Ltd
Publication of GB9500773D0 publication Critical patent/GB9500773D0/en
Publication of GB2285518A publication Critical patent/GB2285518A/en
Application granted granted Critical
Publication of GB2285518B publication Critical patent/GB2285518B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/006—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to produce indicia, symbols, texts or the like
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2219/00—Legends
    • H01H2219/036—Light emitting elements
    • H01H2219/044—Edge lighting of layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2219/00—Legends
    • H01H2219/054—Optical elements
    • H01H2219/056—Diffuser; Uneven surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2219/00—Legends
    • H01H2219/054—Optical elements
    • H01H2219/062—Light conductor

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Push-Button Switches (AREA)
  • Input From Keyboards Or The Like (AREA)

Abstract

A sheet like light guide 5 covering essentially the area of keypad 1 and made of light-conducting material, such as polycarbonate, and provided with an uneven light-transmitting and light-diffusing surface, such as roughened surface 19, against each key 7 to illuminate the key, while the surface of the light guide between the keys is essentially unilluminated. The non-illumination is provided by making the surface of light guide 5 smooth. The roughening can be made on conical surfaces 19 of apertures 13 in light guide 5, through which keys 7 are connected to the electronic parts of circuit board 20 underneath. The illumination of keys 7 and display 2 can be by the same light sources 4 and light guide 5. The keypad 1 may be part of a control panel 3 for electronic devices e.g. a mobile phone. <IMAGE>

Description

LIGHT GUIDE This invention relates to a control panel for use in portable electronic devices, comprising one or more light sources for illuminating the keys and the display typically found on such devices. Suitable applications of the invention include portable telephones and calculators.
Some previously known solutions for illuminating keypads are disclosed in US patent publications; 4,124,879; 4,365,120; 4,636,593; 4,812,831 and 4,916,262. Publication 4,365,120 describes a solution where each key, which is made of light-transmitting material, comprises its own light source, situated in a recess formed in the back of the key. In the solution according to publication 4,124,879, light is distributed around the keypad from a light source on the side of the keypad through light-conducting channels situated between the rows of keys. The channels are provided with matt and reflecting painted surfaces for directing the light. In publication 4,636,593 the keys are part of an element made of translucent elastomeric material, and the light sources are placed between the keys in recesses formed in the element. Publication 4,91 6,262 discloses a structure formed of numerous superimposed, light-transmitting layers in which the keypad is illuminated by light conducting through the lowest layer of the structure and distributing over the whole area of the keypad. In the solution according to publication 4,812,831 the keypad is illuminated by electroluminescence provided by phosphorizing powder or ink contained in a layer under the keypad.
Excluding US patent publication 4,124,879, all the solutions above have light sources placed within the keypad, or arranged to be effective from under the keypad. A drawback with these solutions is that the position of the light source results in the control panel being relatively thick. In publication 4,124,879 the light source is to the side of the keypad, thus overcoming the thickness problem. This solution, however, requires a complex channel structure to direct the light to the keys, usually with numerous surfaces painted with matt or reflecting paint.
According to the present invention there is provided a light guide for a key pad, comprising a sheet-like light-transmitting member having matted or greyed lighttransmitting and light-diffusing surfaces disposed in regions corresponding to keys of a key pad for illuminating the keys of the key pad and having smooth surfaces between the regions corresponding to the keys to inhibit illumination of the surfaces between said regions.
An advantage of the invention is that is provides a simple solution for distributing light to illuminate a control panel for an electronic device and distributing light to the keypad in the iateral direction from one or more light sources situated at the edges of the keypad.
The operation of a sheet-like light guide in accordance with the invention is based on the total internal reflection of light in the sheet material in a similar manner as in light cables containing optic fibres. A beam of light which comes to the surface of the light guide in an inclined manner does not escape the light guide but is reflected back instead, and diffusion of light outside the light guide only occurs in the areas of the light guide which are made uneven for the purpose of diffusing the light. Using the solution, the illumination can be directed to each key of the keypad, while the external areas of the keys remain unilluminated. A single source of light is sufficient to illuminate the keypad, but the control panel is preferably provided with several light sources which can provide different colour light and which can be used to vary the illumination of the keypad. Suitable materials for the light guide include plastic materials, such as polycarbonate, polystyrene or polymethylmethacrylate, which are easy to cast and which transmit light well, though other materials are viable with which the above-mentioned total reflection effect is possible.
In accordance with an advantageous embodiment of the invention each aperture of the light guide corresponding to each key is provided with a roughened surface, while the surface of the light guide between the apertures is smooth. If the light guide is manufactured by casting of plastics such as polycarbonate, both the roughened surfaces on the apertures and the smooth surfaces between them can be provided by the actual casting process. A sufficiently smooth surface keeps a major part of the light beams inside the light guide so that no separate, nontransparent coating is required to keep the surface unilluminated.
The sheet-like light guide preferably comprises an opening under each key through which the key communicates with the circuit board under the light guide, the side surfaces of the openings being roughened to diffuse light. In addition, the openings expand in a concave, conical or pyramid-like manner in the direction of the surface of the control panel, whereby the inclined surfaces of the openings direct light diagonally to the keys on the surface of the control panel.
In accordance with an advantageous embodiment of the invention keys are included in a uniform, sheet-like element located on top of the sheet-like light guide, the element being generally of light-transmitting or translucent material. The said element protects the smooth surfaces of the light guide against scratching which would cause light to diffuse in spots intended to be unilluminated. The element may be a light-transmitting rubber material such as silicone.
The front surface of the element containing said keypad can be even or flat, except for ridges which are of non-transparent silicone, for example, and which form a net or similar figure on the surface of the element, separating the keys from each other.
The ridges make it easier to use the keypad and they form a guard against the accidental pushing of the keys while the device is in a pocket, for instance.
In accordance with an especially advantageous embodiment the sheet-like light guide extends, in addition to the keypad, to the display included in the control panel of the device and comprises one or more roughened surfaces to illuminate the display. This means that the keypad and the display can be illuminated using the same light source(s). In previously known solutions both the keypad and the display required separate light sources. Further, by a single casting a light guide for both the keys and the display can be fabricated.
Embodiments of the invention will now be described, by way of example only and with reference to the accompanying drawings, in which: Figure 1 illustrates a control panel for a mobile phone which is provided with an illuminated keypad and display in accordance with the invention; Figure 2 is an axial cross section of the control panel shown in Figure 1; Figure 3 is an expioded view of Figure 2 showing the components which constitute the control panel; and Figure 4 illustrates the light guide included in the control panel, as viewed in direction IV-IV, of Figure 3, i.e. from above.
Referring to Figures 1 and 2, there is shown a control panel 3 comprising a keypad 1, a display 2, light sources 4 and a substantially planar light guide 5, used to illuminate the display 2 and keys 7.
Referring also to Figure 3, there is shown on the uppermost part of control panel 3 a sheet-like cover 8 made from non-transparent material. The cover 8 includes openings 9, 10 for the display 2 and the keypad 1 respectively.
The keypad 1 comprises a planar element 11 with mutually perpendicular ridges 6 defining the edge of the keys 7. The lower surface of the planar element 11 includes projections 1 2 below each key 7. The planar element 11 is preferably made of translucent silicone, except for the ridges 6 and any numbers and other symbols painted on keys 7, which are non-translucent.
Referring to Figure 3 and Figure 4, there is shown a planar light guide 5 in crosssection and from above respectively. The light guide 5 is preferably made of polycarbonate or a corresponding light-transmitting material to permit illumination of the display 2 and the keypad 1 with light from light sources 4. The light guide 5 is provided with concave apertures 1 3 situated below each key 7 of keypad 1 and from the lower surface with recesses 16-18 for accommodating the light sources 4, a display element 14 and a display control circuit 1 5. The light guide 5 is preferably fabricated by casting and comprises roughened cast surfaces against the concave apertures 1 3 and recesses 16, 17, while the remaining surfaces are cast smooth. Light is guided throughout the light guide 5 using the method of total internal reflection, in which light is reflected back from smooth surfaces of the light guide without the light transmitting outside the light guide. Light transmission is only effective on the roughened surfaces of the light guide where the light is diffused and consequently the light only illuminates the keys 7, and the display element 14. The concave apertures 1 3 in the light guide below the keys 7 have a conical shape such that they increase in radius towards the keys 7 the purpose of which is to direct light diagonally from the roughened conical surfaces 1 9 to the keys 7 on the surface of the control panel 3.
Preferably the light guide 5 extends over the area of the keypad as a plate-like element which except for the openings for the keys is of a unitary configuration.
The keys 7 and the concave apertures 1 3 are arranged in longitudinal and transversal rows corresponding to the usual arrangement of the keys, thus defining a rectangular area for the keypad. The light guide 5 acts as a means for distributing the light through the channels between the rows of the concave apertures 13 to the entire area of the keypad. For effective light distribution the channels should be wide enough in comparison with the size of the concave apertures 13. This applies in particular to channels extending in a direction perpendicular to the direction from which the light is sourced. Preferably the crosssectional area of a channel between a pair of adjacent concave apertures is at least equal to the cross-sectional area of one of the concave apertures. Referring now to the areas of the concave apertures and the keypad as seen in Figures 1 and 2, the sum of all the areas corresponding to the concave apertures is preferably no more than about 25% of the total area of the keypad, thus leaving at least 75% of the keypad's area for the light channels extending between and around the concave apertures. The percentage area of the keypad taken up by the keys, however, is significantly larger which leads to less area on the keypad being unused.
The base of the control panel 3 comprises a printed circuit board 20 provided with electronic components. Referring to Figures 2 and 3, light sources 4 are provided on circuit board 20 on either side of the keypad 1 such that one of the light sources is situated between the keypad 1 and the display 2. Light source 4 may be a light bulb, a fluorescent tube or a light emitting diode. The light may be white or monochromatic, and in accordance with the invention the device can be provided with several light sources of different wavelength, which can be used simultaneously or separately to alter the lighting of keypad 1. If desired, a fluorescent coating may be applied to the roughened surfaces of apertures 13 of the light guide 5 or each key 7 may be dyed with a different colour. Display element 14 situated below the display 2 on circuit board 20 can be in the form of a liquid crystal display which is connected to display control circuit 15 via a lead 21. Metal domes 22 are situated between projections 12 and circuit board 20, the dome being compressed when a key is pushed, either connecting or disconnecting an electrical contact provided on the circuit board.
The components 1, 8, 5 and 20 of the control panel shown in Figure 3 are attached to each other by gluing to form the assembly shown in Figure 2. Keypad 1 is fitted into opening 10 in the cover 8 such that the cover 8 and the keypad 1 together cover the light guide 5 beneath them. The keys 7 communicate with the electrical contacts of the circuit board 20 through the concave apertures 13 of the light guide 5. The light sources 4 are situated within the recesses 1 6 in the light guide 5 and the display element 14 is situated in recess 17 below display 2 in such a manner that the light guide functions as a light-transmitting window protecting the display element 14. The light from light sources 4 is transmitted through the roughened surfaces of recesses 16 and into the light guide 5. The illumination of the keys 7 is then achieved by light transmitting out of the light guide via the roughened conical surfaces 19 of the concave apertures 13. Similarly the display element 14 in display 2 is illuminated via roughened edge surfaces 23 of recess 1 7.
In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention. For example the specific embodiment refers to using rough surfaces, alternatively the illuminating parts of light guide 5 can be provided with relatively coarser roughness, such as different regular-shaped ridges cast on the light guide's surface.
Furthermore, it may be advantageous to mould the light guide 5 so that it can be situated under display element 14.
The scope of the present disclosure includes any novel feature or combination of features disclosed therein either explicitly or implicitly irrespective of whether or not it relates to the claimed invention or mitigates any or all of the problems addressed by the present invention.

Claims (9)

1. A light guide for a key pad, comprising a sheet-like light-transmitting member having matted or greyed light-transmitting and light-diffusing surfaces disposed in regions corresponding to keys of a key pad for illuminating the keys of the key pad and having smooth surfaces between the regions corresponding to the keys to inhibit illumination of the surfaces between said regions.
2. A light guide according to Claim 1, wherein the sheet-like light guide further comprises an aperture in said regions adapted to enable a corresponding key to communicate with a circuit board disposed the light guide, and a side surface of said apertures are matted or roughened to diffuse light incident thereon.
3. A light guide according to Claim 2, wherein the apertures are generally concave and expand conically in a direction towards a major surface of the sheetlike light guide such that the side surface of the apertures direct light diagonally to the keys.
4. A control panel comprising a light guide according to any of the preceding Claims, wherein there are provided keys formed in a uniform, sheet-like element disposed on a top surface of the sheet-like light guide, the element being generally of light-transmitting or translucent material, and the front surface of the element which is otherwise even or flat, comprising non-translucent ridges which form a net or similar figure on the surface of the element, separating the keys.
5. A control panel according to Claim 4, wherein each key comprises a projection disposed in a corresponding aperture of the light guide and projecting from the sheet-like element, a movement of the projection causing an electric contact to be created or disconnected in a circuit board disposed under the light guide.
6. A control panel according to Claim 4 or Claim 5, further comprising at least two light sources disposed at opposing edges of the sheet-like element and from which the light guide distributes light to the keys.
7. A control panel according to any of Claims 4 to 6, wherein the sheetlike light guide extends, in addition to the keys, also to a display disposed in the control panel, and comprises one or more light-transmitting and light-diffusing surfaces to illuminate the display.
8. A control panel according to Claim 7, wherein the light guide extends over the top of the display element in the display such that the light guide forms a light-transmitting window for the display.
9. A control panel according to Claim 8, wherein the display element is situated in a recess formed in a back surface of the light guide, the side surfaces of the recess being matted or roughened to illuminate the display.
GB9500773A 1994-01-10 1995-01-10 Light guide Expired - Fee Related GB2285518B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FI940092A FI95177C (en) 1994-01-10 1994-01-10 Equipped with an illuminated keyboard front panel for an electronic device

Publications (3)

Publication Number Publication Date
GB9500773D0 GB9500773D0 (en) 1995-03-08
GB2285518A true GB2285518A (en) 1995-07-12
GB2285518B GB2285518B (en) 1998-02-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9500773A Expired - Fee Related GB2285518B (en) 1994-01-10 1995-01-10 Light guide

Country Status (2)

Country Link
FI (1) FI95177C (en)
GB (1) GB2285518B (en)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2304233A (en) * 1994-08-03 1997-03-12 Sagem Flat data entry keyboard
WO1997033268A1 (en) * 1996-03-08 1997-09-12 Ericsson, Inc. Light guide for a display or keyboard
EP0801373A1 (en) * 1996-01-16 1997-10-15 Lumitex, Inc. Light emitting panel assemblies for use in automotive applications and the like
WO1998026438A1 (en) * 1996-12-10 1998-06-18 Ericsson Inc. Method and apparatus for providing backlighting for keypads and lcd panels
EP0884525A2 (en) * 1997-06-09 1998-12-16 Lumitex, Inc. Integrated display panel assembly
WO2000074353A1 (en) * 1999-06-02 2000-12-07 Telefonaktiebolaget Lm Ericsson (Publ) Keypad-integrated lcd carrier for mobile telephones
EP1094482A2 (en) * 1999-10-19 2001-04-25 Nokia Mobile Phones Ltd. Light guide for illuminating the display or keyboard of a portable communication device
EP1189130A1 (en) * 2000-09-11 2002-03-20 Günter Witteborg Keyboard for computer
WO2002054427A1 (en) * 2000-12-29 2002-07-11 Vertu Ltd A casing
WO2002054426A1 (en) * 2000-12-29 2002-07-11 Vertu Ltd A casing
GB2371018A (en) * 2000-12-29 2002-07-17 Nokia Mobile Phones Ltd A casing for a portable communication device
GB2371266A (en) * 2000-12-29 2002-07-24 Nokia Mobile Phones Ltd A casing for a portable communication device
GB2371265A (en) * 2000-12-29 2002-07-24 Nokia Mobile Phones Ltd A key arrangement for a portable communication device
GB2373758A (en) * 2001-03-28 2002-10-02 Barbara Sexton Computer keyboard having keys formed on a transparent sheet(s) illuminated by a light distributing sheet thereunder
WO2003083531A1 (en) * 2002-03-27 2003-10-09 3M Innovative Properties Company Interlocking profiled fastening foils used as waveguides for illumination purposes
US6861600B1 (en) 2003-10-01 2005-03-01 Lumitex, Inc. Integrated switch and backlight assembly
EP1523023A1 (en) * 2003-10-10 2005-04-13 Stanley Electric Co., Ltd. Self-lighting type push-button input device
US7006349B2 (en) 2000-12-29 2006-02-28 Vertu Limited Casing
US7511701B2 (en) 2000-12-29 2009-03-31 Vertu Limited Casing having light guide with legends
US7664469B2 (en) 2000-12-29 2010-02-16 Vertu Limited Casing for a portable communication device
DE102008053357A1 (en) * 2008-10-27 2010-06-10 Gigaset Communications Gmbh Electrotechnical device with a lighting arrangement for illuminating a keyboard mat and a display module
US8330725B2 (en) 2010-06-03 2012-12-11 Apple Inc. In-plane keyboard illumination
EP2206529B2 (en) † 2008-12-18 2020-05-27 Sanofi-Aventis Deutschland GmbH Medication delivery device and method of manufacturing a medication delivery device

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US3774021A (en) * 1972-05-25 1973-11-20 Bell Telephone Labor Inc Light emitting device
GB2027551A (en) * 1978-03-15 1980-02-20 Decca Ltd Illuminated panels
GB2065373A (en) * 1979-12-07 1981-06-24 Shinetsu Polymer Co Illuminated key-board switch unit
GB2235295A (en) * 1989-08-24 1991-02-27 Technophone Ltd Light guide for keypads and the like
US5050946A (en) * 1990-09-27 1991-09-24 Compaq Computer Corporation Faceted light pipe
GB2260840A (en) * 1990-05-21 1993-04-28 Eurotherm Recorders Ltd Keyboard having visible and invisible states

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US3774021A (en) * 1972-05-25 1973-11-20 Bell Telephone Labor Inc Light emitting device
GB2027551A (en) * 1978-03-15 1980-02-20 Decca Ltd Illuminated panels
GB2065373A (en) * 1979-12-07 1981-06-24 Shinetsu Polymer Co Illuminated key-board switch unit
GB2235295A (en) * 1989-08-24 1991-02-27 Technophone Ltd Light guide for keypads and the like
GB2260840A (en) * 1990-05-21 1993-04-28 Eurotherm Recorders Ltd Keyboard having visible and invisible states
US5050946A (en) * 1990-09-27 1991-09-24 Compaq Computer Corporation Faceted light pipe

Cited By (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2304233A (en) * 1994-08-03 1997-03-12 Sagem Flat data entry keyboard
GB2304233B (en) * 1994-08-03 1999-05-26 Sagem Flat data entry keyboard
US5975711A (en) * 1995-06-27 1999-11-02 Lumitex, Inc. Integrated display panel assemblies
EP1975958A3 (en) * 1996-01-16 2009-09-02 Solid State Opto Limited Light emitting panel assemblies for use in automotive applications and the like
EP0801373A1 (en) * 1996-01-16 1997-10-15 Lumitex, Inc. Light emitting panel assemblies for use in automotive applications and the like
US6367940B1 (en) * 1996-01-16 2002-04-09 Solid State Opto Limited Light emitting panel assemblies for use in automotive applications and the like
US6886956B2 (en) 1996-01-16 2005-05-03 Solid State Opto Limited Light emitting panel assemblies for use in automotive applications and the like
US6158867A (en) * 1996-01-16 2000-12-12 Lumitex, Inc. Light emitting panel assemblies for use in automotive applications and the like
WO1997033268A1 (en) * 1996-03-08 1997-09-12 Ericsson, Inc. Light guide for a display or keyboard
US5746493A (en) * 1996-03-08 1998-05-05 Ericsson Inc. Light guide for a display or keyboard
WO1998026438A1 (en) * 1996-12-10 1998-06-18 Ericsson Inc. Method and apparatus for providing backlighting for keypads and lcd panels
EP0884525A3 (en) * 1997-06-09 1998-12-23 Lumitex, Inc. Integrated display panel assembly
EP0884525A2 (en) * 1997-06-09 1998-12-16 Lumitex, Inc. Integrated display panel assembly
WO2000074353A1 (en) * 1999-06-02 2000-12-07 Telefonaktiebolaget Lm Ericsson (Publ) Keypad-integrated lcd carrier for mobile telephones
EP1094482A3 (en) * 1999-10-19 2003-08-20 Nokia Corporation Light guide for illuminating the display or keyboard of a portable communication device
US6550927B1 (en) 1999-10-19 2003-04-22 Nokia Mobile Phones Limited Light guide for a communication unit
EP1094482A2 (en) * 1999-10-19 2001-04-25 Nokia Mobile Phones Ltd. Light guide for illuminating the display or keyboard of a portable communication device
GB2355569A (en) * 1999-10-19 2001-04-25 Nokia Mobile Phones Ltd Light Guide
EP1189130A1 (en) * 2000-09-11 2002-03-20 Günter Witteborg Keyboard for computer
GB2371265B (en) * 2000-12-29 2005-08-10 Nokia Mobile Phones Ltd A casing
US7664469B2 (en) 2000-12-29 2010-02-16 Vertu Limited Casing for a portable communication device
GB2371265A (en) * 2000-12-29 2002-07-24 Nokia Mobile Phones Ltd A key arrangement for a portable communication device
GB2371266A (en) * 2000-12-29 2002-07-24 Nokia Mobile Phones Ltd A casing for a portable communication device
WO2002054426A1 (en) * 2000-12-29 2002-07-11 Vertu Ltd A casing
US7522943B2 (en) 2000-12-29 2009-04-21 Vertu Limited Casing
US7511701B2 (en) 2000-12-29 2009-03-31 Vertu Limited Casing having light guide with legends
GB2371018B (en) * 2000-12-29 2005-04-06 Nokia Mobile Phones Ltd A Casing
US7006349B2 (en) 2000-12-29 2006-02-28 Vertu Limited Casing
GB2371018A (en) * 2000-12-29 2002-07-17 Nokia Mobile Phones Ltd A casing for a portable communication device
WO2002054427A1 (en) * 2000-12-29 2002-07-11 Vertu Ltd A casing
GB2371266B (en) * 2000-12-29 2005-08-10 Nokia Mobile Phones Ltd A casing
GB2373758A (en) * 2001-03-28 2002-10-02 Barbara Sexton Computer keyboard having keys formed on a transparent sheet(s) illuminated by a light distributing sheet thereunder
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Also Published As

Publication number Publication date
GB9500773D0 (en) 1995-03-08
FI940092A (en) 1995-07-11
FI95177B (en) 1995-09-15
FI940092A0 (en) 1994-01-10
GB2285518B (en) 1998-02-18
FI95177C (en) 1995-12-27

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