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 
  • G02F1/15—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 an electrochromic effect
  • G02F1/1514—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 an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material
  • G02F1/1523—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 an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising inorganic material
  • G02F1/1525—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 an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising inorganic material characterised by a particular ion transporting layer, e.g. electrolyte
• • 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 
  • G02F1/15—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 an electrochromic effect
  • G02F1/1514—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 an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material
  • G02F1/1516—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 an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising organic material
• • 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 
  • G02F1/15—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 an electrochromic effect
  • G02F1/153—Constructional details
  • G02F1/1533—Constructional details structural features not otherwise provided for
• • 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 
  • G02F1/15—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 an electrochromic effect
  • G02F1/153—Constructional details
  • G02F1/155—Electrodes

Definitions

• the invention relates, generally, to the field of electrically control lable displays and, more particularly, to the field of electrochromic displays.
• Electrochromic displays have been developed which display information through a change in the color of portions in the display via electrochemical reaction of an active material to achieve a color change.
• this color change is from white to blue.
• the change is from white to violet.
• Such displays require substantial power and time to write or erase displayed information. The quantities of power required are undesirably large, especially for battery operation, and the time required to change displayed information makes such materials unacceptable for many display applications. None of these known displays provides more than a single color against a background.
• Rare earth diphthalocyanines are known from prior publications to have electrochromic properties in which the color of the diphthalocyanine can change over a period of about eight seconds upon application of a potential difference across an electrochemical cell having a diphthalocyanine film on one of the electrodes. See for example P. N. Moskalev and I. S. Kirin, "Effect of the Electrode Potential on the Absorption Spectrum of a Rare-Earth Diphthalocyanine Layer," Opt. i Spektrosk, 29, 414 (1970), and P. N. Moskalev and I. S. Kirin, "The Electrochromism of Lanthanide Diphthalocyanines” Russian J. P'nys. Chem., 46, 1019 (1972).
• the diphthalocyanine does not require large amounts of power to change color, but the long period required for the color to change makes known diphthalocyanine performance characteristics unacceptable when measured against display requirements.
• the display of the instant invention overcomes many of the problems of prior art displays via utilization of metal diphthalocyanine complexes as the electrochromically active material and a lowfreezing metal chloride as the electrolyte in an electrochromic display cell. Rapid color changes in less than 50 milliseconds are achieved, thus alleviating the slow switching time previously reported for rare earth diphthalocyanine complexes. Power requirements are small because of the low power switching characteristics of the display material, because of its high optical absorption, and because the display exhibits an open circuit memory of from several minutes to several hours, depending on its construction. A multicolor, i.e. more than two colors, display is achieved through use of a range of voltages applied between display and counter electrodes.
• Color reversal of displayed information and the background against which it is displayed is achieved through use of display electrodes in the background portions of the viewing area as well as in the character segments.
• the use of an aqueous solution of a selected metal chloride for the electrolyte expands the operating range to a very low temperature, for example, on the order of -80°C if the electrolyte is a concentrated solution of lithium chloride.
• FIG. 1 illustrates a cross-section through a typical transmissive display cell configuration.
• Display cells in accordance with the invention may be divided into two general types.
• One type comprises reflective display cells which are designed to be viewed by reflected light only.
• the other type comprises transmissive display cells which are designed to be reviewed by light transmitted therethrough.
• Display cell 10 may include a case or similar structure (not shown) which supports transparent face plate 14 which constitutes the viewing surface or area of the display cell.
• Rear plate 12 is also transparent (in the transmissive cell).
• a plurality of transparent electronically conductive display electrodes are preferably deposited on the inner surface of face plate 14.
• the display electrodes include character segments 28, or other pattern areas, the number and the arrangement ofwhich are determined in accordance with the quantity and types of information the cell is intended to be able to display.
• a thin layer 30 of an electrochromic metal diphthalocyanine is disposed on the display electrode character segments 20, for exposure to the electrolyte 1-18.
• the metal diphthalocyanine film 30 comprises the electrochromic material of the display cell.
• a counter electrode 22 is preferably disposed on a portion of the rear plate 12 which constitutes the back surface of cavity 16.
• the cell also contains a separate reference electrode 24 when a potentiostatic drive system is used.
• the construction of a typical display cell 10 is illustrative only. Reference is made to the Nicholson application noted above in the prior art discussion, the content of which is included herein by reference, for details of cell construction.
• This invention is directed to an electrochromic display which utilizes a metal diphthalocyanine material and an improved electrolyte which permits improved operation.
• the electrolyte is a concentrated aqueous solution of a metal chloride which freezes far below the freezing point of water.
• a particularly desirable electrolyte comprises a solution of 30 weight percent calcium chloride in water. This composition is near that of the eutectic mixture which freezes at approximately -55°C. Consequently, low temperature and fast response time cell operation can be achieved.
• This electrolyte has been used with a lutetium diphthalocyanine display cell and has been successfully operated over at least 900 cycles at approximately -50°C. Multicolor electrochromic switching occurred in this display cell with excellent color quality under these conditions. In addition, no visually detectable change in switching time was observed. The color transformation in the electrochromic material continued to occur in less than 50 milliseconds as the solution was cooled from approximately room temperature to -50°C.
• KCl potassium chloride
• aqueous solution of lithium chloride is appropriate too.
• the eutectic mixture in this chemical system contains 25 weight percent LiCl and has a melting temperature of approximately -80°C.
• the ionized material need not be formed from a chloride salt although metal chloride solutions are among the lowest melting systems which are essentially inert, can be used as aqueous electrolytes. It must be understood, of course, that a ternary - or other type of mixture containing two or more salts in v/ater may also be used.
• a nickel counter electrode was utilized with a three-electrode drive circuitry.
• Counter electrode materials more appropriate for display cells with 2 or 3 electrode drives in concentrated chloride media include silver-silver chloride, lead-lead chloride and a solid mixture consisting of the electrochromic dye in an oxidized and a reduced form.
• the counter electrode generally is kept out of the viewing field to improve operation and viewability.
• a diphthalocyanine electrochromic counter electrode may be preferred over the metal-metal chloride because of the demonstrated fast electrode response of the diphthalocyanine material at low temperature.
• the display cell is characterized by a suitable structural configuration which is similar to the existing cellswhich are known in the art. However, this cell includes the improvement of a new and unique class of electrolyte materials which permit the cells to operate at extremely low temperatures without sacrificing the desirable operating characteristics usually encountered in an electrochromic display cell.

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• Physics & Mathematics (AREA)
• Nonlinear Science (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Inorganic Chemistry (AREA)
• Exposure Control For Cameras (AREA)
• Indication In Cameras, And Counting Of Exposures (AREA)
• Devices For Indicating Variable Information By Combining Individual Elements (AREA)
• Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (4)

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Citations (8)

• 1980
  • 1980-03-17 JP JP55501328A patent/JPH038524B2/ja not_active Expired - Lifetime
  • 1980-03-17 WO PCT/US1980/000340 patent/WO1980002462A1/en unknown
  • 1980-05-07 FR FR8010203A patent/FR2456357A1/fr active Granted

Patent Citations (8)

Non-Patent Citations (2)

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