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| The Zenithal Bistable Device: From concept to consumer |
J. C.iff Jones, SID 07 Digest of Technical Papers, Volume XXXVIII, Book II, 40.1, pp 1347 - 1350.
The paper is reproduced with kind permission from the Society for Information Display. |
| The first commercial use of the Zenithal Bistable Display (ZBDŽ) is for electronic point of purchase (epopT) signage in the retail sector. As a reflective bistable display, this novel LCD technology only consumes power if the image is updated. It is addressed using a simple passive matrix and consequently allows large amounts of information to be displayed using low cost STN drivers. The operating principles, manufacturing method and performance of ZBD are reviewed. |
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| Novel Geometries of the Zenithal Bistable Device |
J. Cliff Jones , SID 06 DIGEST, 37, 2, pp 1626 - 1629
The paper is reproduced with kind permission from the Society for Information Display. |
| Zenithal bistable LCDs use profiled surfaces to induce bistability in an otherwise standard twisted nematic display. However, the control offered by such surfaces is readily adapted to suit other display modes. For example, pretilt, surface latching field and stable state on cooling are all independently controllable. Three novel modes are proposed: a pi-cell that combines a millisecond optical response and stable bend state; a simple multi-stable device with four greys, and a bistable device with improved viewing angle when operating in transmission. |
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| High Image Content Zenithal Bistable Devices |
J.C. Jones and S. M. Beldon, (2004) SID Digest, 10.4, pp 104 – 107
The paper is reproduced with kind permission from the Society for Information Display. |
| Grating aligned zenithal bistable LCDs offer a low cost route to ultra-low power displays with excellent appearance. The flexibility of the grating design allows each pixel to have several latching thresholds without extra fabrication cost. Combining this approach with a novel addressing method allows each row driver to address several lines of information. For example, this technique allows high numbers of greys to be addressed using digitally weighted spatial dither, but without the extra-cost of additional electronic drivers. Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Transflective and Single Polariser Reflective Zenithal Bistable Displays. |
J. Cliff Jones, Phil Worthing, Guy Bryan-Brown and Emma Wood, Proceedings of SID 2003, 14.1, pp 190-193
The paper is reproduced with kind permission from the Society for Information Display. |
| Transflective displays are ideal for portable applications used in both bright sunlight and darkened rooms. Display bistability is also advantageous for ensuring low power consumption, but the choice for transflective geometries is then severely limited. Grating-aligned Zenithal Bistable Devices (ZBD(tm)) are readily fabricated in either single polariser reflective or transflective modes using a number of different device geometries. Both retardation and polarisation rotationmodes are reported. Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Low Voltage Zenithal Bistable Devices with Wide Operating Windows. |
J. Cliff Jones, Steve Beldon, Peter Brett, Matt Francis and Mark Goulding, Proceedings of SID 2003, 26.3, pp 954-958
The paper is reproduced with kind permission from the Society for Information Display. |
| Key parameters for any bistable device are operating voltage and temperature range. The development of liquid crystal mixtures for use with grating aligned Zenithal Bistable Displays (ZBD™) is described for the first time. Latching at voltages less than 5V, with 20V addressing faster than 80µs per line and operation over a temperature range from -20°C to 80°C are all demonstrated in the same 4µm device. Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Greyscale in Zenithal Bistable LCD: The Route to Ultra-Low Power Colour Displays. |
J.C. Jones, S.M. Beldon and E.L. Wood, Proceedings of the 7th Asian Symposium on Information Display (ASID '02) p205-208
The paper is reproduced with kind permission from the Society for Information Display. |
| Zenithal Bistable Devices exhibit rugged image storage, excellent optical performance, fast latching and infinite multiplexibility. These properties arise from the use of the grating layer used to align a nematic liquid crystal. Such gratings also offer a high degree of design flexibility. In the present work, grating shape is varied within each pixel to introduce error-free analogue greyscales. Passive matrix waveforms, suitable for use with commercial STN drivers are reported, and shown to produce at least 7 error-free greys in a test cell. A method for achieving 64 static greys is described.Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Meeting the display requirements for portable applications using Zenithal Bistable Devices. |
J.C. Jones, P. Brett, Guy Bryan-Brown, A. Graham, E.L. Wood, R.J. Scanlon and H-L. Martin, Proceedings of the 33rd International Symposium on Information Display, SID '02, v1 p90-93
The paper is reproduced with kind permission from the Society for Information Display. |
| Ease of manufacture, optical performance, ultra-low power, high resolution over large areas and rugged image storage are all important display requirements for portable devices. Recent advances in the performance of Zenithal Bistable Nematic LCD are compared to these key requirements for application in hand-held devices, smart cards and electronic readers.Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Large Area High Resolution Portable ZBD Display. |
E.L Wood, P.J. Brett, Guy Bryan-Brown, A. Graham, R.M. Amos, S. Beldon, E. Cubero, J.C. Jones, Proceedings of the 33rd International Symposium on Information Display, SID '02, v1 p22-95
The paper is reproduced with kind permission from the Society for Information Display. |
| A 7" diagonal 200dpi resolution, ultra low power Zenithal Bistable LCD ideal for portable applications is demonstrated for the first time. The lightweight module exhibits the same high contrast, wide viewing angle and rugged bistability shown previously but the design gives high quality text and graphics using conventional STN drivers.Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Zenithal Bistable Displays: Towards the electronic book with a simple LCD |
| J.C. Jones, J.R. Huges, A. Graham, P. Brett, Guy Bryan-Brown and E.L. Wood, The Seventh International Displays Workshop, Kobe, Japan (December 2000) PLC2 2, pp301-304 |
| ZBD is a simple nematic LCD that uses grating alignment to produce zenithal bistable states with differing director pre-tilts. It offers ultra-low power, image retention even after shock and an appearance that surpasses that of STN. Ultimately, the device is ideal for portable books. The route taken to produce high levels of image content using this technology is described. |
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| Zenithal Bistable Displays |
| J.C. Jones, P. Brett, Guy Bryan-Brown, A. Graham and E.L. Wood, Proceedings of Electronic Information Display Conference, Excel Conference Hall, London, UK (November 2000) |
| The advantages of using bistability have long been recognised as a means to display large amounts of information on passively addressed liquid crystal devices. Recently, there has been a resurgence of interest in bistable displays, one of the more promising of which is the zenithal bistable device (ZBD). |
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| Zenithal Bistable Device (ZBD) using Plastic Substrates |
| Guy Bryan-Brown, Proceedings of 20th International Displays Research Conference, Palm Beach, Florida, USA (September 2000) pp 229 - 232 |
| High contrast reflective ZBD cells have been made using PES polymer substrates. A written image is maintained after compression or flexing the cell which is unique for bistable LCDs. Cells have also been made containing PEDOT polymer electrode layers. |
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| The Zenithal Bistable Device: A liquid crystal display with ultra-low power consumption |
| Dr. C. Jones, Proceedings of ASET International Forum on Low Power Displays, Kokuyo Hall, Shinagawa, Tokyo Japan (July 2000) |
| The relationship between power and complexity proves restrictive for products such as the electronic book, where battery life is limited to several hours. In the near future, greater complexity will be required in products that combine the functions of the mobile phone, palm-top computer and electronic book. Display power will be a major issue for such applications. |
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| Zenithal bistable device (ZBD) suitable for portable applications |
E.L. Wood, Guy Bryan-Brown, P. Brett, A. Graham, J.C. Jones and J.R. Hughes, Proceedings of SID 2000, 31 , 11.2, pp124 - 127
The paper is reproduced with kind permission from the Society for Information Display. |
| Zenithal bistable display devices have been made which are compatible with size and functionality with current mobile phone or pager displays. Radical improvements in the viewing characteristics, particularly in reflective mode are shown. Furthermore, this paper describes low voltage operation, fast latching times and broad-matrix addressing. |
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| Zenithal bistable device (ZBD) suitable for portable applications |
E.L. Wood, Guy Bryan-Brown, P. Brett, A. Graham, J.C. Jones and J.R. Hughes, Proceedings of SID 2000, 31 , 11.2, pp124 - 127
The paper is reproduced with kind permission from the Society for Information Display. |
| Zenithal bistable display devices have been made which are compatible with size and functionality with current mobile phone or pager displays. Radical improvements in the viewing characteristics, particularly in reflective mode are shown. Furthermore, this paper describes low voltage operation, fast latching times and broad-matrix addressing. |
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| Novel bistable liquid crystal displays based on grating alignment. |
| J. Cliff Jones, Guy Bryan-Brown, Emma Wood, Alistair Graham, Pete Brett and Jonathan Hughes, Proceedings of SPIE, 3955 , 84 - 93 |
| The ability of surface relief gratings to align liquid crystals has been known for many years. Renewed interest has recently been stimulated through the invention of novel devices in which the grating gives the additional benefit of bistability. This allows complex images to be retained without constant updating, and without the need for Thin Film Transistors at each pixel. Two types of bistable liquid crystal have been demonstrated: azimuthal bistability using bi-gratings, and zenithal bistability using gratings that give surface alignment to the liquid crystal director parallel to the local surface normal. The latter type is called ZBD and gives exceptional performance compared to all other bistable display technologies. This is because the nematic liquid crystal has different tilts in the direction of the applied field, allowing latching times of better than 40 microseconds (at 30V) and switching thresholds below 10V. The orientation of the liquid crystal is not required to change at the surface when switching between the two states and so there are no problems with image sticking. Also, the bistability is surface induced, which makes the states exceptionally tolerant to mechanical stress. An 83 by 90 pixel display is demonstrated, illustrating the potential of this exciting new technology. |
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| Optimisation of the Zenithal Bistable Nematic Liquid Crystal Device (ZBD™) |
| Guy Bryan-Brown, E.L. Wood and J.C. Jones, Proceedings of the 18th International Displays Research Conference, Seoul, Korea (Oct 1998) pp1051 - 1054 |
| Further studies on the ZBD configuration have demonstrated that switching can be obtained across a wide range of cell spacings without loss of bistability. Variation of grating profile across a pixel is presented as a more controllable greyscale method. Optical modelling has shown that wide viewing can be obtained for reflective or transmissive configuration. Calculations show that a 1/8 VGA ZBD panel requires only 6mJ of energy per update. |
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| Novel configuration of zenithal bistable nematic liquid crystal device |
J.C. Jones, E.L. Wood, Guy Bryan-Brown and V.C. Hui, Proceedings of Society for Information Display International Symposium. Digest of Technical Papers Volume XXIX, Anaheim, (May 1998) pp858 - 861
The paper is reproduced with kind permission from the Society for Information Display. |
| Bistable nematic devices offer zero power image retention and wide temperature operating range. An overview is given of several approaches to obtaining bistability. The use of grating surfaces to obtain bistable anchoring is then discussed in more detail. Finally, we present new results in the zenithal bistable device (ZBD) demonstrating both greyscale and excellent shock stability.Copyright, Society for Information Display. Contact the Society for Information Display for additional copies of this paper. |
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| Grating aligned bistable nematic devices |
| Guy Bryan-Brown, E.L. Wood, C.V. Brown, J.C. Jones, I.C. Sage and P. Brett, Proceedings of The Electronic Information Displays Conference, Sandown, Surrey UK, (November 1997) |
| Bistable nematic devices offer zero power image retention and a wide temperature operating range. An overview is given of several approaches to obtaining bistability. The use of grating surfaces to obtain bistable anchoring is then discussed in more detail. Finally, we present new results the zenithal bistable device (ZBD) demonstrating both greyscale capability and excellent shock stability. |
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| Grating aligned bistable nematic device |
| Guy Bryan-Brown, E.L. Wood, C.V. Brown, J.C. Jones, I.C. Sage and P. Brett, Proceedings of International Displays Workshop (IDW), Nagoya, Japan (November 1997) PLC2-1 , pp261 - 264 |
| Bistable nematic devices offer zero power image retention combined with a wide temperature range and good shock stability. An overview is given of several approaches to obtaining bistability. The use of grating surfaces to obtain bistable anchoring will then be discussed in more detail. Finally, new results will be presented from work carried out on the zenithal bistable device (ZBD.) |
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| Grating aligned bistable nematic device |
Guy Bryan-Brown, C.V. Brown, J.C. Jones, E.L. Wood, I.C. Sage, P. Brett and J. Rudin, Proceedings of Society for Information Display International Symposium. Digest of Technical Papers Volume XXVIII, Boston, MA, USA (1997) 5.3 , pp37 - 40
The paper is reproduced with kind permission from the Society for Information Display. |
| A grating surface treated with a homeotropic surfactant is found to support two stable pre-tilt configurations when the groove depth to pitch ratio is optimum. This allows the realisation of a new flexolectrically selected bistable nematic display operating with sub millisecond switching pulses of less than 25V. |
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