Radiant energy – Luminophor irradiation – Self-luminous article
Reexamination Certificate
1999-12-22
2001-10-23
Hannaher, Constantine (Department: 2878)
Radiant energy
Luminophor irradiation
Self-luminous article
C340S332000, C442S076000
Reexamination Certificate
active
06307207
ABSTRACT:
FIELD OF INVENTION
The present invention generally relates to an unpowered photoluminescent emergency egress marking system having utility for demarcation of egress route(s) from a structure such as a building, vehicle, aircraft, train, ships, etc. More particularly, the present invention relates to a carpet containing photoluminescent fibers woven therein, providing essentially uniform luminescence across the surface area of the emergency egress path and/or across informational icons formed therein.
BRIEF DESCRIPTION OF THE RELATED ART
All aircraft, as well as many other common carriers and buildings, are required to have backup lighting systems which demarcate emergency egress paths. Such systems assist passengers in locating and moving to exits during an emergency. Emergency egress pathway marking systems are broadly classified as “active” or “passive,” the former requiring a source of electrical or other power to provide illumination, and the latter providing illumination with no electrical or other power source.
Active emergency egress pathway marking systems and componentry are well known in the art. Cassidy, et al. U.S. Pat. No. 5,661,374 discloses serial/parallel configuration and constant current power supply circuitry for modular lighting strips using LED's, electroluminescent elements, or incandescent bulbs as active illuminating elements. Iwans U.S. Pat. No. 4,029,994 describes the use of flashing strobe type lights to demarcate emergency egress pathways, and to lead passengers in a proper direction along a pathway by creating the effect of light beams moving along the markers toward the emergency exits.
Active emergency egress pathway marking systems suffer a variety of drawbacks, particularly as applied to aircraft. Since the primary purpose of the systems is to provide active illumination during emergency, such as following a crash or after single or multiple aircraft system failures, these systems require a separate, independent, redundant power source—typically emergency batteries.
Thus, the active marking system, and its accompanying power source and distribution wiring, comprise an independent aircraft system with its own inspection, testing, and maintenance requirements. Further, in a severe crash involving significant structural damage, the marking lighting elements, their power supply wiring, and/or the batteries could be severed from the relevant portion of the craft or otherwise sustain damage impairing the function or operability of the system or its components. This may result in failure of the system to fully illuminate under the very circumstances in which its proper operation is most critical.
Active system designs may include various redundancies to increase their reliability, but this also increases costs, complexity, and maintenance requirements.
Active emergency egress pathway marking systems may be enhanced or even replaced by passive systems. Since passive systems require no electrical power source or power distribution wiring, they are less complex; more easily installed, replaced, and modified; as a result, and in contrast to active systems, such passive systems may be substantially or even totally maintenance-free. Since passive systems are never switched “on” or “off,” they function whenever ambient lighting is removed or severely decreased.
Passive systems can provide emergency egress marking functionality following even severe crash damage, and “fail” in their essential function only if physically displaced by the crash or other structural damage from their fixed spatial relationship to the emergency exits.
Generally, passive emergency egress pathway marking systems utilize photoluminescent material that stores energy when exposed to certain wavelength bands present in most ambient light sources and slowly releases visible energy long after the ambient source is removed.
Photoluminescent materials are well known in the art, and include for example zinc sulfide, calcium sulfide, and alkaline earth metal type aluminate as described in Murayama et al., U.S. Pat. No. 5,424,006. The intensity of illumination provided by photoluminescent material s begins to decay immediately upon the removal of ambient light. However, human visual perception increases shortly after the removal of ambient light, as physiological adjustments occur to the eye, and individuals progress to “night vision.” Thus, photoluminescent materials may provide sufficient luminous energy to an emergency egress path w ay for several hours following the removal of ambient light.
Passive emergency egress pathway marking systems utilizing photoluminescent material are well known in the art.
Pitman, et al. U.S. Pat. No. 5,724,909 discloses a strip type pathway marker using photoluminescent material, comprising a base element mounted to e.g. a floor, wall, or stair riser, and a separate photoluminescent source releasably attached thereto. Pitman discloses the use of these photoluminescent s trips to demarcate the outlines and intersections of building structures, such as walls, stairs, etc.
It is known in the art to use photoluminescent strip lighting to demarcate exit paths in aircraft. The photoluminescent strips are typically mounted at or near the floor of the aisle in parallel spaced relationship, and extend longitudinally along the aisle toward the exit, defining a path between the two strips, for passenger egress.
While the use of photoluminescent strips to demarcate structures and define pathways overcomes many of the disadvantages associated with active emergency egress pathway marking systems, the photoluminescent strip systems themselves have several inherent disadvantages.
Photoluminescent strips rely on ambient lighting to be activated. In certain environments the locations of the ambient light sources are not conducive to optimum exposure of the photoluminescent strips. As the strips form the outline of the pathway, their location is essentially fixed. The ambient light sources therefore need to be positioned to adequately illuminate the strips within a desired minimum exposure duration. Also, moveable items such as suitcases, briefcases, etc. may block the activation of the strips in localized areas and eliminate the continuous marking required of strips.
The luminance intensity, or brightness, of photoluminescent strips is considerably lower than that of active lighting technologies, i.e., LEDs, electroluminescent lamps, or incandescent lighting elements.
Additionally, as discussed above, the luminous intensity of photoluminescent material decreases rapidly following the removal of ambient light. Accordingly, particularly in a smoke-filled environment, parallel photoluminescent strips may be less visible and hence less effective in guiding passengers to the exit than would a more conspicuous passive egress pathway marking configuration.
Furthermore, any directional or other informational indicators formed in photoluminescent strips, such as arrows, pictograms, or text, would necessarily be of a small size and therefore of marginal effectiveness for communicating information to passengers during an emergency.
Accordingly, it is an object of the present invention to provide an improved passive emergency egress pathway marking system.
It is another object of the invention to provide a larger area for charging than in conventional strip systems. The increased area afforded by a fully carpeted pathway would be more forgiving to the specific location(s) of ambient lighting and less susceptible to the detrimental effects of occasional obstructions.
It is another object of the invention to provide a passive emergency egress system utilizing photoluminescent material, which provides an increased luminous flux in relation to the thin parallel photoluminescent strips conventionally known and used in the art.
It is another object of the present invention to provide a means for communicating directional, locational, or other information to occupants during an emergency, activation of which is automatic, being an integral part of the passive marking system.
Other objects a
Astronics Corporation
Hannaher Constantine
Hultquist Steven J.
Israel Andrew
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