GB2143987A - Time display for LCD analog timepiece - Google Patents
Time display for LCD analog timepiece Download PDFInfo
- Publication number
- GB2143987A GB2143987A GB08412242A GB8412242A GB2143987A GB 2143987 A GB2143987 A GB 2143987A GB 08412242 A GB08412242 A GB 08412242A GB 8412242 A GB8412242 A GB 8412242A GB 2143987 A GB2143987 A GB 2143987A
- Authority
- GB
- United Kingdom
- Prior art keywords
- reflector
- dial
- liquid crystal
- indicia
- perceived
- 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.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133553—Reflecting elements
-
- G—PHYSICS
- G04—HOROLOGY
- G04G—ELECTRONIC TIME-PIECES
- G04G9/00—Visual time or date indication means
- G04G9/0023—Visual time or date indication means by light valves in general
- G04G9/0029—Details
- G04G9/0035—Details constructional
-
- G—PHYSICS
- G04—HOROLOGY
- G04G—ELECTRONIC TIME-PIECES
- G04G9/00—Visual time or date indication means
- G04G9/02—Visual time or date indication means by selecting desired characters out of a number of characters or by selecting indicating elements the position of which represent the time, e.g. by using multiplexing techniques
- G04G9/06—Visual time or date indication means by selecting desired characters out of a number of characters or by selecting indicating elements the position of which represent the time, e.g. by using multiplexing techniques using light valves, e.g. liquid crystals
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/133374—Constructional arrangements; Manufacturing methods for displaying permanent signs or marks
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nonlinear Science (AREA)
- Mathematical Physics (AREA)
- Optics & Photonics (AREA)
- Electric Clocks (AREA)
Abstract
An LCD Analog watch includes a liquid crystal display with radial segments representing "hands" 3, 4, 5 to show hours, minutes and seconds and having a reflector with time indicating indicia thereon disposed beneath the "hands". The indicia appear in the plane of the reflector and the "hands" provide images spaced above the reflector, giving an illusion of hands of a conventional mechanical watch spaced from a watch dial. <IMAGE>
Description
SPECIFICATION
Time display for LCD analog timepiece
This invention relates to a time display for a timepiece with a liquid crystal display, such as wristwatch of the type known variously as an
LCD analog watch or a liquid crystal analog (LCA) watch, which represents the time simulating conventional mechanical hour and minute hands. More particularly, the invention relates to an improved means to create an illusion of depth or intentional parallax to simulate mechanical hands above a dial.
LCA watches have been proposed and known for some time, an early example being shown in US-3,5409,209 which discloses an electronic watch with radial hour, minute and second hands simulated on a liquid crystal display of the dynamic scattering type with no polarizers, i.e. a display in which the liquid crystal between opposed conductive plates is ordinarily clear when the plates are not activated, but becomes turbid to scatter the light and obscure the plates beneath when the plates are activated. The patent employs conductive radial segments evenly spaced on the back of the crystal or on the face of the dial.
The crystal is spaced from the dial a short distance and the space filled with suitable dynamic scattering liquid crystal material.
Dynamic scattering displays have been found generally unsatisfactory, since the activated segments are silvery and reflective in appearance and are difficult to read. Twisted nematic displays with polarizers have been developed which consume very little power and are particularly suitable for wrist watches.
For the most part, these displays are used to display the time using digits rather than radial "hands". Digits do not need any spatial frame of reference, and the primary emphasis in liquid crystal digital watches has been to provide improved readability and contrast.
Various types of reflectors have been provided, generally with diffusers to provide a uniform background for the digits and to increase the brightness of the display. For example, reflectors of metallic foil have commonly been placed behind the rear polarizer layer of the display. In cases where the display includes a light source for nighttime viewing, a "transflector" has been used. The transflector will reflect incident ambient light during daytime operation, and will also be translucent to light from a light source behind the display. A transflector typically comprises a translucent frosted glass or plastic sheet and/or a thin metallic layer or deposit.
US.-4,196,973 shows a transflector, while US--4, 106,859, US-4,249,801 and Us-3,881 ,809 show LCD reflectors, these only being exemplary of many patents. The foregoing reflectors are generally intended to reflect and diffuse light and have no indicia inscribd on them.
US-3,973,338 shows a digital liquid crystal display in which the glass substrate on the reflector side of the display is reduced in thickness in order to reduce a shadow effect caused by reflection from the upper side of the lower glass substrate. An irregular or lightscattering reflector is used and the stated purpose of the invention is to reduce or eliminate a shadow effect. US-3,910,033 shows a construction for a watch dial, not in a liquid crystal display, which creates an interference pattern by adding a thick layer on a watch dial so that inteferring reflection patterns are created frkom the dial and from the surface of the layer.
LCA watches have heretofore been designed along the same lines as LCD digital watches, which results in a flat or single dimensional apearance of the hands. On the other hand, persons accustomed to conventional watches with hands are also accustomed to the three dimensional effect or parallax due to the spacing between the hands and the top of the watch dial, creating shadows and perception of distance between the hands and the dial.
The illusion of conventional mechanical hands would be enhanced by a construction which caused liquid crystal display hands to appear to be spaced from the dial.
Accordingly, one object of the present invention is to provide an LCA timepiece such as a watch in which the hands appear to be spaced from the conventional watch dial.
Another object of the invention is to provide an LCA timepiece such as a watch giving an illusion of a conventional watch with analog hands.
Briefly stated, the present invention provides a time display for a liquid crystal analog timepiece of the type having a liquid crystal display with radially extending segments adapting to simulate the hands of a timepiece comprising a reflector dial disposed beneath the liquid crystal display, said reflector dial having a reflective surface adapted to reflect incident light to form a perceived visual image of a timepiece hand at a location spaced from the reflector dial, said reflector dial also having light absorbing indicia thereon disposed beneath the segments and adapted to provide perceived images in the reflector dial plane, whereby the hands appear to be spaced above said indicia.
An embodiment of the present invention will now be described by way of example, reference being made to the accompanying drawings, in which:
Figure 1 is a plan view of an LCA watch embodying a time display according to the invention.
Figure 2 is an enlarged cross sectional elevation taken along line 2-2 in Fig. 1,
Figure 3 is a diagrammatic cross-sectional drawing, not to scale, illustrating the theory of operation, and
Figure 4 is a further diagrammatic drawing illustrating operation of the invention.
Referring now to Fig. 1 of the drawings, a timepiece comprises a wrist watch 1 with an exterior case 2 containing an electronic module and power source (not shown). The module includes an integrated circuit adapted to provide multiplexed output drive signals to actuate a twisted nematic, field effect, liquid crystal display of a type also well known in the art. The display provides visible radial segments, which advance clockwise from one position to the next, in the manner of conventional hour, minute and second hands. In the embodiment shown, a short inner radial segment 3 simulates an hour hand, a short outer radial segment 4 simulates a second hand, and two such segments are combined as a long segment to simulate a long minute hand 5. Visible beneath hands 3, 4 and 5 are timekeeping indicia, such as numerals 6, radial minute or "seconds" markers 7.In the embodiment shown, the numerals are imprinted on a partially reflective annular track 8.
Setting of the timepiece is accomplished by means of a side-mounted command bar 9 which actuates internal switches inside the case. Any type of switch actuating mechanism may be employed, but in the preferred embodiment, the actuator is of the type shown in
GB 2 100 518A. The hands 3, 4, 5 are obtained in a twisted nematic field effect liquid crystal display by imposing electrical potentials in a preselected sequence on transparent conductive areas on closely spaced upper and lower glass substrates. The space between the substrates contains an aligned, twisted nematic liquid crystal material which, when subjected to an electric field between opposed segments and viewed through crossed polarizers disposed above and below the glass substrates will render the hands visible.The field is created by selectively and periodically applying multiplexed electric potentials to the desired conductive areas or electrodes. A suitable display and driving circuit for a liquid crystal analog timepiece is disclosed in US 4,209,974 there also being other suitable circuits and arrangments known in the art.
Referring to Fig. 2 of the drawings, the electronic module in a plastics pod 10 is enclosed by a case back 11. A transparent front lens 1 2 is sealed within an annular recess 14 in watch case 2 by a gasket 15. An integrated annular ledge 1 6 with a decorativa bevel 1 7 is visible through the lens 1 2 and forms a frame for the display.
A display with reflector dial, indicated generally at 18, is held in place between pod 10 and ledge 16. The display includes a top polarizer 19, a top glass substrate 20, a bottom glass substrate 21, and bottom polarizer 22, and a reflector dial 23. The liquid crystal material is sealed between the upper and lower glass substrates 20, 21 and aligned so that it will rotate incident polarized light in a manner known to those skilled in the art.
In accordance with the present invention, the reflector dial has a light-reflecting surface.
Preferably the reflector dial is a metal sheet, suitably a sheet of brass material which is nickel plated and then silver plated to give a highly reflective surface. This is then mechanically brushed or burnished to give the desired reflective characteristics. The reflector dial has indicia thereon of light-absorbing material, preferably imprinted thereon by transfer printing using ordinary light-absorbing paint in the form of numerals, symbols, radial markers, etc. The annular track 8 may be either imprinted or etched to provide a partially lightabsorbing background which serves to provide a perceived image in the reflector dial plane.
The indicia are also arranged in an annular pattern around the centre of the display so that they are located beneath one or more of the hands 3, 4 and 5. They may be in a circular, elliptical, or racetrack pattern as well.
Referring now to Fig. 3 of the drawings, a diagrammatic representation of a portion of the display shows the polarizer sheets 19, 22, the glass substrates 20, 21, and the reflector dial 23. The liquid crystal material is indicated at 24. Two opposed transparent conductive segments 25, 26 on the upper and lower glass substrates respectively may be activated to provided one of the timepiece hands. A light absorbing indicia 27 on the reflector dial 23 represents a portion of a numeral, hour marker or other indicia providing spatial relationship for indicating time. An incident ray of ambient light 28 is polarized by top polarizer 19, rotated 90 degrees by liquid crystal 24, passes through crossed bottom polarizer 22 and is reflected by the reflective portion of dial 23. The reflected ray is polarized by bottom polarizer 22, and passes through the activated conductive areas 25, 26. Since the rotative power of the liquid crystal is cancelled by the field between conductive areas, the light passes through without rotation and is then extinguished by the crossed polarizer 1 9.
The eye perceives an image in the plane of the top polarizer at 29. On the other hand, the light absorbing indicia 27 is perceived by the eye in the plane of the reflector dial 23.
Under some viewing conditions, depending upon the angle of viewing, an incident ray 30 will create a fainter perceived image at 31, which appears to be a shadow of the darker image 29.
Referring to Fig. 4 of the drawings, where the perceived image 29 of the hand in the plane of the top polarizer is seen together with the indicia 27 on the reflector dial in the plane of the refleCtor, an illusion is created of space between hand image 29 and indicia 27, similar to conventional timepiece hands above a dial. Depending upon whether the images are viewed from a position 32 or from a position 33, image 29 will either be on one side or on the other side of image 27. Therefore, a thee-dimensional effect is obtained due to the eyes of the viewer seeing the images from slightly different angles.
Various other types of reflective surfaces on reflector dial 23 having light absorbing contrasting areas thereon may be used to create the illusion of spacing between the liquid crystal analog hands and the surface of the reflector dial. For example, such surfaces may consist of special radial brushing, i.e. outwardly from the centre of the dial. This serves to reflect the ambient light at different angles and give an effect equivalent to light absorption over preshaped sectors of the dial.
Various other types of liquid crystal displays may be used. A guest/host liquid crystal display, without polarizers, operates to create a perceived image of the hand in the space between the two glass substrates. The effect of parallax is not as great, because the spacing is due only to one thickness of glass rather than two thicknesses. However, the principle of operation is the same.
Claims (8)
1. A time display for a liquid crystal analog timepiece of the type having a liquid crystal display with radially extending segments adapting to simulate the hands of a timepiece comprising a reflector dial disposed beneath the liquid crystal display, said reflector dial having a reflective surface adapted to reflect incident light to form a perceived visual image of a timepiece hand at a location spaced from the reflector dial, said reflector dial also having light absorbing indicia thereon disposed beneath the segments and adapted to provide perceived images in the reflector dial plane, whereby the hands appear to be spaced above said indicia.
2. A time display according to Claim 1, where said liquid crystal display is the guest/ host type providing a perceived hand image between said substrates.
3. A time display according to Claim 1, wherein the liquid crystal display is the twisted nematic field effect type with top and bottom polarizers. wherein the perceived image is formed in the plane of the top polarizer.
4. A time display for a liquid crystal analog timepiece comprising a twisted nematic field effect liquid crystal material between top and bottom transparent substrates, said substrates having transparent conductive areas thereon arranged to provide radially extending segments for simulating the hands of a timepiece, and top and bottom polarizers disposed on either side of said substrates, and a reflector dial disposed beneath the bottom polarizer, said reflector dial having a reflective surface thereon adapted to reflect incident light to form perceived hand images in the plane of the top polarizer, and having light absorbing indicia thereon disposed beneath the segments and adapted to provide perceived images of said indicia in the reflector dial plane, whereby the hands appear to be spaced above said indicia.
5. A time display according to Claim 4, wherein said indicia comprise printed numerals on the reflector dial disposed beneath said perceived hand images.
6. A time display according to Claim 4, wherein said indicia comprises an annular track of partially light-absorbing areas disposed beneath said-perceived hand images.
7. A time display according to Claim 4, wherein said indicia comprise a plurality of radial hour markers arranged around the reflector dial in a closed annular path beneath said perceived hand images.
8. A time display for a liquid crystal analog timepiece, substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US51570783A | 1983-07-20 | 1983-07-20 |
Publications (2)
Publication Number | Publication Date |
---|---|
GB8412242D0 GB8412242D0 (en) | 1984-06-20 |
GB2143987A true GB2143987A (en) | 1985-02-20 |
Family
ID=24052410
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08412242A Withdrawn GB2143987A (en) | 1983-07-20 | 1984-05-14 | Time display for LCD analog timepiece |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2143987A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5130827A (en) * | 1990-09-10 | 1992-07-14 | Litton Systems, Inc. | Display cell having active and passive areas |
EP0625721A1 (en) * | 1993-05-18 | 1994-11-23 | Negretti Aviation Limited | Liquid crystal display |
WO1998010326A1 (en) * | 1996-09-05 | 1998-03-12 | Northern Telecom Limited | Shadow mask for backlit lcd |
EP0890866A2 (en) * | 1997-06-09 | 1999-01-13 | Seiko Epson Corporation | Display device and electronic watch |
US5929952A (en) * | 1997-06-24 | 1999-07-27 | Ericsson Inc. | Static three-dimensional graphical background for liquid crystal displays |
FR2936619A1 (en) * | 2008-09-30 | 2010-04-02 | Nemoptic | LCD device for use in e.g. identification tag in fish shop, has ink patterns printed between liquid crystal layer and reflective layer such that one of patterns is hidden by superimposed pixels when pixels are in blocking state |
-
1984
- 1984-05-14 GB GB08412242A patent/GB2143987A/en not_active Withdrawn
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5130827A (en) * | 1990-09-10 | 1992-07-14 | Litton Systems, Inc. | Display cell having active and passive areas |
EP0625721A1 (en) * | 1993-05-18 | 1994-11-23 | Negretti Aviation Limited | Liquid crystal display |
WO1998010326A1 (en) * | 1996-09-05 | 1998-03-12 | Northern Telecom Limited | Shadow mask for backlit lcd |
EP0890866A2 (en) * | 1997-06-09 | 1999-01-13 | Seiko Epson Corporation | Display device and electronic watch |
EP0890866A3 (en) * | 1997-06-09 | 2000-01-19 | Seiko Epson Corporation | Display device and electronic watch |
US5929952A (en) * | 1997-06-24 | 1999-07-27 | Ericsson Inc. | Static three-dimensional graphical background for liquid crystal displays |
FR2936619A1 (en) * | 2008-09-30 | 2010-04-02 | Nemoptic | LCD device for use in e.g. identification tag in fish shop, has ink patterns printed between liquid crystal layer and reflective layer such that one of patterns is hidden by superimposed pixels when pixels are in blocking state |
Also Published As
Publication number | Publication date |
---|---|
GB8412242D0 (en) | 1984-06-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6271901B1 (en) | Liquid crystal display device with two reflective polarizers providing metallic appearance effects | |
US4488818A (en) | Watch with an analog display device the dial of which is formed by a liquid crystal display cell | |
US6292439B1 (en) | Watch | |
US3722206A (en) | Self-illuminated liquid crystal timepiece | |
US4043638A (en) | Liquid crystal display mounted behind a front glass | |
WO2000031596A1 (en) | Timepiece | |
US7581873B2 (en) | Watch crystal having an optical effect and watch fitted with such a crystal | |
WO1999004322A1 (en) | Watch | |
US6577360B1 (en) | Liquid crystal display | |
GB1579467A (en) | Electrooptic display device | |
CA1085072A (en) | Electrically controlled liquid crystal display device for successive display of one information in the absence of control voltage, and others in the presence thereof | |
EP0929838B1 (en) | Shadow mask for backlit lcd | |
GB2052809A (en) | Timepiece | |
US4043116A (en) | Timepiece comprising a flat display device exposed through an opening in a case | |
JP2004271259A (en) | Clock module | |
US4281406A (en) | Water-proof case for digital electronic timepieces | |
CN1208701C (en) | Sequence control method for display unit composed of two overlapped indicator | |
US4540242A (en) | Liquid crystal display element | |
US5881024A (en) | Combination display timepiece equipped with el illumination | |
GB2143987A (en) | Time display for LCD analog timepiece | |
US3908355A (en) | Electrooptical timepiece display with conventional hour and minute hands | |
US4217035A (en) | Liquid crystal display | |
JP2007256062A (en) | Electronic component, electronic equipment, and dial | |
JPH07128458A (en) | Structure of timepiece dial | |
US5412625A (en) | Structural graphic display |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |