Mixed signaling device for rooms with mesopic lighting

Details Mixed signaling device for rooms with mesopic lighting Mixed signaling device for rooms with mesopic lighting

2000-07-26

2001-12-04

O'Shea, Sandra (Department: 2875)

Illumination

Light fiber, rod, or pipe

Light emitting diode

C362S559000, C362S812000, C040S579000

Reexamination Certificate

active

06325530

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
This invention claims priority of French Patent Application No. 9910683 filed Aug. 18, 1999, titled “Mixed Signaling Device For Rooms With Mesopic Lighting” by Marie-Rose Bernazzani, et al.
FIELD OF THE INVENTION
The invention relates to safety signaling and more particularly in rooms that have relatively low main specific lighting.
BACKGROUND OF THE INVENTION
It is well known that the manufacture of photographic products must be carried out in rooms with very low light. It often happens that the manufacturing and finishing operations for light sensitive photographic products take place in dark rooms in which the lighting is mesopic lighting. This is due to the fact that the light sensitive products are fogged with lighting that can be very low.
Safety regulations require employers to indicate the emergency exits to their personnel using permanent panels. In premises with mesopic lighting, it is necessary to illuminate such panels so that they can be seen.
U.S. Pat. No. 5,365,411 titled “Exit Signs With LED Illumination,” Nov. 15, 1994, by Rycroft et al., and U.S. Pat. No. 5,105,568 titled “Illuminated Sign Having Stencil Panel And Reflector Panel,” Apr. 21, 1992, by Branning describe signaling panels comprising a box surrounding a light source and a screen bearing the information to be displayed and having light transparent zones and arranged in front of the source so that the luminous information can be seen by an observer. In U.S. Pat. No. 5,105,568 the sources are arranged to surround the transparent zones. In U.S. Pat. No. 5,365,411 the sources are arranged on the edges of the box and the light is reflected and diffused to illuminate the information panel uniformly.
It is an object of the invention to produce a signaling device that can be used in a room with mesopic lighting to limit to the minimum the interference light caused by the presence of the device in the room.
It is another object of the invention to enable the utilization of the same device when the room is exceptionally illuminated with photopic light.
SUMMARY OF THE INVENTION
This object is achieved by means of a signaling device for rooms with mesopic lighting, comprising a light-tight box having a base, side walls practically perpendicular to the base, an upper part of the box extending between the side walls forming a light-opaque information panel, and a light source inside the box. The device is characterized in that the information panel comprises a symbol, which is in the form of slots whose width is between 0.5 mm and 1.5 mm to allow the light to escape from the box in diffused form, and whose luminance is between 0.02 cd/m
2
and 0.5 cd/m
2
.
In one advantageous embodiment, the light source emits radiation whose spectral width is relatively narrow and centered on 590 nm.
In another particularly advantageous embodiment, the information panel comprises one main side facing outwards and presenting, in photopic light, a background having a first appearance, and zones that surround the slots, which mark out the symbols represented by the slots, and which presents a second appearance, different from the first, so that the symbols formed by the zones can be seen in photopic lighting.


REFERENCES:
patent: 4969068 (1990-11-01), Williams
patent: 5105568 (1992-04-01), Branning
patent: 5365411 (1994-11-01), Rycroft et al.
patent: 5584555 (1996-12-01), Larsson
patent: 5921012 (1999-07-01), Caivano
patent: 41 09 532 A1 (1991-10-01), None
patent: 1 585 392 (1981-03-01), None

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