Optical: systems and elements – Optical modulator – Light wave temporal modulation
Reexamination Certificate
1999-07-02
2001-11-13
Ben, Loha (Department: 2873)
Optical: systems and elements
Optical modulator
Light wave temporal modulation
C359S271000, C359S273000, C359S275000, C348S148000, C340S438000
Reexamination Certificate
active
06317248
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to busbars utilized in electrically powered cells. In particular, this invention relates to edge and internal busbars utilized in electrochromic devices. This invention also relates to edge and internal busbars that can be utilized in other electrically powered cells such as electroluminescent and photochromic devices, thin-film batteries, and other cells that use geometries similar to the electrochromic devices described herein. Further, this invention relates to control circuits and methods to control the coloration of such electrochromic devices through an intermittent application of power.
Electrochromic (EC) devices are devices in which a change in an electrical signal applied to the EC device results in a change in an optical property of the EC device. Typically, the optical property is optical transmittance, although other properties can be affected such as, for example, optical spectral distribution or polarization. Electrochromic devices can be used for many applications, such as rear view automotive mirrors, windows, sunroofs, shades or visors for automotive and mass transportation applications, architectural windows, skylights, displays, light filters and screens for light pipes, displays, and other electro-optical devices.
A variety of technologies exist for producing chromogenic members. “Chromogenic devices”, as used herein, is employed as commonly known in the art. Examples of these chromogenic devices include electrochromic devices, photochromic devices, liquid crystal devices, user-controllable-photochromic devices, polymer-dispersed-liquid-crystal devices, and suspended particle devices.
For example, electrochromic devices are discussed by N. R. Lynam and A. Agrawal in “Automotive Applications of Chromogenic Materials”,
Large Area Chromogenics: Materials
&
Devices for Transmittance Control
, Optical Engineering Press, Bellingham, Wash. (1989), incorporated herein by reference. Other pertinent references include N. R. Lynam, “Electrochromic Automotive Day/Night Mirrors”,
SAE Technical Paper Series
, 87036 (1987); N. R. Lynam, “Smart Windows for Automobiles”,
SAE Technical Paper Series
, 900419 (1990); C. M. Lampert, “Electrochromic Devices and Devices for Energy Efficient Windows”,
Solar Energy Materials
, 11, 1-27 (1984); JP 58-20729; and U.S. Pat. Nos. 3,521,941, 3,807,832, 4,174,152, 4,338,000, 4,652,090, 4,671,619, 4,702,566, 4,712,879, 4,793,690, 4,799,768, Re. 30,835, 5,066,112, 5,073,012, 5,076,674, 5,122,647, 5,142,407, 5,148,014, 5,239,406, and 5,657,149 each incorporated herein by reference.
Electrochromic panels are also discussed by Sapers, S. P., et al. in “Monolithic Solid-State Electrochromic Coatings for Window Applications”, Proceedings of the Society of Vacuum Coaters Conference (1996), incorporated herein by reference, with regard to devices of the type shown in FIG.
1
E. Devices comparable to that shown in
FIG. 1E
, and having photovoltaic layers for self-biasing operation are also described in U.S. Pat. No. 5,377,037.
Other related references of interest include U.S. Pat. No. 5,241,411, U.K. Patent No. 2,268,595, Japanese Laid-Open Patent No. Appln. No. 63-106730, Japanese Laid-Open Patent No. Appln. No. 63-106731, and U.S. Pat. No. 5,472,643, each incorporated herein by reference. Also pertinent is International Application No. PCT/US 97/05791, incorporated herein by reference, which pertains to electrochromic devices that can vary the transmission or reflection of electromagnetic radiation by applying an electrical stimulus to an EC device. International Application No. PCT/US 97/05791 uses a selective ion transport layer in combination with an electrolyte having at least one redox active material to provide a high-performance device.
Also suitable for use in this invention are liquid crystal devices such as those described by N. Basturk and J. Grupp in “Liquid Crystal Guest-Host Devices and Their Use as Light Shutters”,
Large Area Chromogenics: Materials & Devices for Transmittance Control
, Optical Engineering Press, Bellingham, Wash. (1989), incorporated herein by reference.
User-controllable-photochromic devices (UCPC) are discussed in U.S. Pat. No. 5,604,626, entitled “Novel Photochromic Devices”, incorporated herein by reference.
Polymer-dispersed-liquid-crystal (PDLC) devices are described by N. R. Lynam and A. Agrawal, “Automotive Applications of Chromogenic Materials”,
Large Area Chromogenics: Materials
&
Devices for Transmittance Control
, Optical Engineering Press, Bellingham, Wash. (1989), incorporated herein by reference.
Suspended particle devices are discussed in U.S. Pat. No. 4,164,365, incorporated herein by reference.
Examples of chromogenic devices that emit light are described in Applied Physics Letters, Vol. 71, page 1293 (1997).
Examples of chromogenic devices that can store image patterns due to a change in an optical property of a material are described in U.S. Pat. No. 5,744,267, incorporated herein by reference.
The general control of chromogenic devices is discussed in U.S. Pat. Nos. 4,793,690, 4,799,768, 5,007,718, and 5,424,898, incorporated herein by reference.
The phenomenon of prolonged coloration of chromogenic devices is discussed in U.S. Pat. Nos. 5,076,673 and 5,220,317, each incorporated herein by reference.
FIGS. 1A through 1E
depict typical examples of known electrochromic devices, while
FIG. 1F
shows another known type of chromogenic device.
For example,
FIG. 1A
depicts a layered EC device which includes a substrate
101
, transparent conductor
103
, electrochromic (redox) medium
105
, transparent conductor
103
′ and substrate
101
′.
FIG. 1B
illustrates a layered EC device which includes a substrate
101
, transparent conductor
103
, EC layer
107
, electrolyte (redox medium)
109
, transparent conductor
103
′ and substrate
101
′.
FIG. 1C
shows another layered EC device having a substrate
101
, transparent conductor
103
, EC layer
107
, ion-selective transport layer
111
, electrolyte (redox medium)
109
, transparent conductor
103
′ and substrate
101
′.
Still another such EC device is shown in FIG.
1
D. This device includes a substrate
101
, transparent conductor
103
, EC layer
107
, electrolyte
113
, counterelectrode
115
, transparent conductor
103
′ and substrate
101
′.
FIG. 1E
shows an EC device having a substrate
101
, transparent conductor
103
, EC layer
107
, electrolyte (ion-conductive layer)
117
, counterelectrode
115
and transparent conductor
103
′.
A typical liquid crystal or PDLC device is shown in FIG.
1
F. This device includes a substrate
201
, transparent conductor
203
, liquid crystal or PDLC medium
205
, transparent conductor
203
′ and substrate
201
′.
Since the above chromogenic devices are known to those skilled in the art, a detailed explanation of the manner of construction and operation of such devices is not necessary.
In general, it is important to distribute the voltage to an electrochromic (EC) device uniformly in order to (i) maintain the uniformity of the coloration and bleaching of the EC device during changes between such states of coloration and bleaching, (ii) to improve uniformity in such colored and bleached states, and finally (iii) to enhance the kinetics of coloration and bleaching. As the size of an EC device increases, it becomes increasingly more difficult to maintain the desirable voltage distribution uniformity because increased size typically leads to increased resistance of various components. Such increased resistance results in voltage drops and current losses that adversely affects the uniformity of voltage distribution.
In other electrical devices, a particular spatial voltage distribution profile often is desired. As the size of such devices increases, similar to the example of EC devices, it also becomes increasingly more difficult to maintain the desired spatial voltage distribution profile because of the increasing electrical resistance of various compon
Agrawal Anoop
Cronin John
Denesuk Matthew
Kennedy Steve
LeCompte Robert
Ben Loha
Donnelly Corporation
Fitzpatrick ,Cella, Harper & Scinto
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