Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2000-06-16
2003-03-04
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S205000
Reexamination Certificate
active
06528782
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to skylights employing chromogenic filters, and more particularly, to improvements in the light harvesting, light control, electrical operation, electrical control and serviceability of such skylights.
BACKGROUND OF THE INVENTION
Skylights are frequently employed in various types of structures for practical, as well as aesthetic reasons. They bring in natural light, reducing the need for artificial light. This saves electricity and reduces cost.
Various characteristics of the conventional tubular skylight can affect the wave length of the light transmitted. For example, as shown in
FIG. 1
, a tubular skylight A, as known in the art, may reduce UV transmission without significant reduction of visible light if light entering the tubular skylight reflects from a highly reflective, but UV absorbtive, tubular inside surface B. UV transmission may further be diminished by light passing through a collection dome C and a light diffuser D.
Finally, skylights have recently seen the suggested addition of chromogenic filters. Such filters hold the promise of controlling the intensity of light transmitted through a skylight. Various technologies for producing user-controllable chromogenic filters have been proposed. Examples include electrochromic filters, liquid-crystal filters, user-controlled-photochromic filters, polymer-dispersed-liquid-crystal filters, and suspended-particle filters. These are described in U.S. provisional patent application Ser. No. 60/091,678, filed Jul. 2, 1998 and U.S. patent application Ser. No. 09/347,807, Busbars for Electrically Powered Cells, now U.S. Pat. No. 6,317,248, and filed Jul. 2, 1999, and U.S. patent application Ser. No. 08/914,876, Chromogenic Window Assembly Construction and Other Chromogenic Devices, now U.S. Pat. No. 6,039,390, filed Aug. 20, 1997, each incorporated herein by reference.
The term user controllable is used herein in the same sense as in the above-mentioned U.S. Pat. No. 6,039,390, entitled Chromogenic Window Assembly Construction and Other Chromogenic Devices. There it is said:
The term “user-controllable” is used in the sense that the appearance of a chromogenic device can be regulated. Photochromic devices, because their coloration is a function of light intensity, are not directly “user-controllable”. However, systems incorporating photochromic devices can be designed in which users can regulate such devices. For the purposes of this application, those systems would also be considered “user-controllable”.
Chromogenic light filters are very useful in regulating the light through skylights at the discretion of the user. A description of various user controllable chromogenic technologies is given in the U.S. application Ser. No. 09/347,807 filed Jul. 2, 1999, incorporated herein by reference. Typically, such chromogenic devices are based on electrochromic technology, user controllable photochromic technology, liquid crystal technology and suspended particles which orient in an electric field. User controlled thermochromic devices (U.S. Pat. No. 5,525,430, incorporated by reference herein) have also been suggested where the user can vary the temperature of the chromogenic member to alter its transmission. Chromogenic filters are useful for both tubular skylights and conventional skylights. One example of technology useful for chromogenic filters is the electrochromic device discussed by N. R. Lynam and A. Agrawal in “Automotive Applications of Chromogenic Materials,”
Large Area Chromogenics: Materials
&
Devices for Transmittance Control
, C. M. Lampert and C. G. Granqvist, editors, Optical Engineering Press, Bellingham, Washington (1989), which is hereby incorporated by reference.
The present invention relates to improving:
(1) Effectiveness of light harvesting by a skylight and reduction of sharp images or light patterns in the building interior such as might adversely affect a work area.
(2) Placement of sensors in the skylight system to effectively control the transmittance of the light through the chromogenic filters.
(3) Skylights with mechanical shades.
(4) Skylights in which the power to the chromogenic filters is provided by solar cells and that preferably are remotely activated by the user so that they can be easily retrofitted.
(5) Serviceable chromogenic light filters that can be easily repaired and/or replaced.
SUMMARY OF THE INVENTION
In accordance with the present invention, user-controllable chromogenic skylights are provided with improved light control. In a preferred embodiment, the invention provides for user control of the intensity of light from a skylight through the control of a chromogenic filter in combination with one or more of a remotely controllable mechanical shutter that provides darkness during the day and an internally mounted lamp to provide nighttime illumination. Short of complete blockage of light by the mechanical shutter, intermediate light intensity control is achieved by control of the user-controllable chromogenic filter.
All type of skylights will benefit from this invention, but some aspects of this invention are more suitable for the tubular skylights.
Like skylights described in the above-mentioned patent applications, skylights embodying features of the current invention may have an outward end with a light capturing dome, a tubular light path and an interior diffuser capping the skylight's inward end. In this configuration, the chromogenic filter resides within or at the end of the tubular light path below the exterior dome. As the light travels through the skylight, its intensity is modified by the chromogenic filter that intercepts the light path. The skylight optionally includes a secondary diffuser (or diffusers), the mechanical shutter and the lamp. Control circuitry is provided for the chromogenic filter, the lamp and the mechanical shutter. Preferably, the control circuitry for the chromogenic filter, the shutter and the lamp share a single user-accessible interface by which the user sets the chromogenic filter transmittance, opens or closes the mechanical shutter, turns the lamp on or off, and perhaps sets the lamp intensity.
A user interface can be hard-wired into the control circuitry. Preferably, it is linked by radio frequency or infrared transmission. A sensor to receive an infrared transmission is located to be in a direct line of sight of the user interface. In a preferred embodiment, it is located out of sight behind the interior light diffuser. Also, in a preferred embodiment, multiple sensors increase the area within the building interior from which line of sight communication by a user's remote control interface is available. Preferably, a visible or audible indicator communicates that the sensor has received the user's commands. The indicator can be a simple lighted or flashing LED, an audible tone generator, a bank of LEDs connected to act as a bar graph, an alphanumeric display, etc. The indicator is particularly useful to signal the receipt of a command and the start of a change of transmittance by the chromogenic light filter since this is a gradual change not immediately apparent.
The chromogenic filter allows for user control of the intensity of light and possibly color that is transmitted through the skylight. Any of a number of chromogenic materials can function in this invention as mentioned above. Chromogenic materials change transmittance in response to an external signal. For example, electrochromic materials change transmittance based on an applied electrical potential. A filter control circuit supplies the electrical potential (the filter signal), which causes a transmittance that corresponds to a light intensity set-point. The light intensity set-point of the filter control circuit is substantially under the user's control.
In one embodiment, the chromogenic filter closes the interior end of the skylight rather than the diffuser. A diffuser is located intermediate the light harvesting dome and the filter. This filter can be frosted or patterned such as with hemisp
Agrawal Anoop
Hansen Stephan
Lecompte Bob
Tonazzi Juan Carlos Lopez
Zhang Raymond
Fitzpatrick ,Cella, Harper & Scinto
Le Que T.
Schott Donnelly LLC
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