WO2000013163A9

WO2000013163A9 - Outdoor sign with sealed sign module

Info

Publication number: WO2000013163A9
Application number: PCT/US1999/019320
Authority: WO
Inventors: Timothy J Nicholson; John P Nicholson; Gordon M Melby; Steve J Mchenry; Paul C Freeberg
Original assignee: Addco Inc
Priority date: 1998-08-26
Filing date: 1999-08-25
Publication date: 2000-08-31
Also published as: AU5583399A; WO2000013163A1

Abstract

A display module for an outdoor sign (20) has a light weight plastic enclosure (56) with an open interior containing circuitry (62) and light emitting diodes (64) and is hermetically sealed from exterior elements. Means for minimizing deflection of the front panel (60) are incorporated into the enclosure (56). One such element includes a single restrictive vent (80) for pressure equalization to minimize deflection of the face portion (60). The elements also include an internal diaphragm (86) to maintain the integrity of the hermetic seal. A feature and advantage of the display is that moisture and other containments are effectively precluded from entry into the chamber (70) containing the circuitry (62) and LED's (64) of the display sign (20).

Description

OUTDOOR SIGN WITH SEALED SIGN MODULE

This invention relates to changeable signs, more particularly to changeable message signs viewable at a distance of at least 150 feet and that are suitable for outdoor use. The application is related to co-owned applications, Serial No. 08/634,031, Modular Message Board, and Serial No. 08/833,945, Enhanced Modular Message Board, as well as the co-owned applications entitled Outdoor Sign with Sealed Sign Module, and Changeable Message Sign System with Reconfigurable Sign Screen which have the same filing date at the instant application. All of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION Changeable outdoor message signs typically utilize light emitting diodes (LED's) as pixels in a matrix to provide changeable messages. Such diodes can generated substantial amounts of heat. Additionally these changeable message signs are used outdoors and are thus exposed to the elements including direct sunlight, rain, and snow. It is critical that these outdoor signs which often warn of hazardous conditions must remain operational in varying conditions with minimal maintenance. The outdoor highway signs typically have message screens which are in the range of six by ten feet or even greater. Signs of such size utilize numerous LED's and also thus have much surface area exposed to the sun which can cause rapid heating of the interior of the message sign. Moreover, moisture such as from rain, snow, sleet and the like is inimical to the electronics and other internal components of these highway message signs. Therefore, ideally these message signs would be sealed from the elements. However, such sealing can trap heat within the screen enclosure and can create significant pressure differentials between the interior and exterior which can cause failures or distortion of the screen enclosure. Handling the heat from the L.E.D.'s and the sun within such sign enclosures has been dealt with the past by way of fans and other types of air conditioning equipment. Effective hermetic sealing of such sign enclosures has not been effectively accomplished. Sealing of any sign enclosures which are subjected to wide variations in temperatures can cause significant pressure differential and extreme deflection of the sign face.

Typically large sign enclosures will simply have water drains in the bottom of said to eliminate the inevitable accumulation of water in the interior of said containers. LED's have been embedded in epoxies with circuitry also sealed in control panel type application where the characters are viewable from a few feet. These types of designs are not workable for large exterior signage due to the added cost and difficulty of manufacture as well as the added weight and difficulty in repair or replacement of individual LED's.

SUMMARY OF THE INVENTION In a preferred embodiment of the invention, a display module for an outdoor sign has a light weight plastic enclosure with an open interior containing circuitry and light emitting diodes and is hermetically sealed from exterior elements. Means for minimizing deflection of the front panel are incorporated into the enclosure. One such means includes a single restrictive vent for pressure equalization to minimize deflection of the face portion. The means also includes an internal diaphragm to maintain the integrity of the hermetic seal. A feature and advantage of the invention is that moisture and other containments are effectively precluded from entry into the chamber containing the circuitry and LED's of the display sign.

An additional advantage of the invention is that the diaphragm operates to equalize pressure differential created by the internal heating of the sign enclosure by the LED's while maintaining the hermetic seal. An additional advantage and feature of the invention is that the second chamber which is vented to the exterior of the sign module is defined by a protruding structure on the module. Said protruding structure which provides structural strength to the module enclosure and also provides structure for engagement with the mounting track portion of the support structures .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an outdoor changeable message sign incorporating the invention.

FIG. 2 is a exploded view of a display module incorporating the invention.

FIG. 3 is a rear elevational view of a display module incorporating the invention.

FIG. 4 is a cross-sectional view taken at line 4-4 of FIG. 3.

FIG. 5 is the same view of FIG. 4 showing an alternative embodiment of the invention.

FIG. 6 is a sectional view through a display module showing a reinforced front display panel .

FIG. 7 is a sectional view through line 8-8 of FIG. 7.

DETAILED SPECIFICATION

Referring to FIG. 1 a changeable outdoor modular message sign is shown and is generally designated with the numeral 20 The outdoor sign principally comprises a support structure 22 and a message screen 24. The support structure consists of a trailer 28 with ground engaging wheels 30, a standard 34 and support tracks 36. The standard 34 is typically articulated such that the screen 24 may be raised and lowered for transportation or adjusted for optimal visibility to viewers. The sign screen is comprised of a plurality of display modules 40 which are interchangeable and are configured to be positioned adjacent to one another such as in the rectangular matrix pattern as shown. The display sign also includes a power supply 44 and a control unit 46 for powering and controlling the modular display signs. The power supply may be an electric generator or batteries or rechargeable batteries with solar power assist, all of which are known in the art. The control unit 46 is programmable to provide any desired variable message. The control units work in conjunction with the individual display modules to initiate addressing of each of the individual display modules and transferring an appropriate bit map to each of the display modules whereby a message is displayed on the display side 50 of the screen 24.

Referring to FIGS. 2, 3, 4, and 5, details are shown of an individual display module. Such a changeable message sign is fully disclosed in the related applications 08/634,031 and 08/833,945. Each display module is principally comprised of a enclosure 56 formed of a base portion 58 configured as a tray. A transparent front face portion 60, a circuit board 62 with pixel elements 64 which in the preferred embodiment are light emitting elements such as L.E.D. 's, and a flexible membrane 66. The flexible membrane may be made of latex which is suitable for the configuration as shown in FIGS. 2 and 4. The membrane in such a case is elastomeric providing flexibility and resiliency. Additionally, the membrane may be configured as a inflatable bellows 66 which can either be relatively non- expandable, formed of such materials as PVC, or can again be formed of expandable materials, such as latex, to allow expansion.

The flexible membrane 66 defined within the open interior 68 of the enclosure, a first chamber 70, and a second chamber 72. In the embodiment of FIG. 4 the second chamber is also defined by the structural protruding portion 76 which has an inside surface 78 which forms a part of the periphery of the second chamber. The second chamber has a restrictive vent 80 which extends to the exterior 82 of the display module enclosure 56. The vent may be supplementally shielded by way of additional filters or screens indicated by the dashed structure 86 of FIG. 4. Known filters or screens such as fiber material, or carbon granules or sintered beads, plastic or metal, would be suitable. Such supplemental filter member can provide primary or secondary isolation of the circuitry and LED ' s .

Referring specifically to FIG. 5, an alternative embodiment of the flexible membrane is shown whereby the second chamber is defined exclusively by the interior surface 86 of the flexible membrane configured as a bellows.

The structural protruding portion 76 of the display module 40 serves to provide additional structural rigidity to the enclosure 56 as well as providing the recess 90 in the interior of the enclosure for defining the second chamber as in FIG. 4 or for providing a suitable location for a bellows as in FIG. 5. The support track 36 is sized to engage within two or more of the structural protruding portions 76 as shown in FIG. 3. Electrical connections can be made by way of mechanical electrical connectors 94 on the display module that connect to conductors 96 in the support such as disclosed in the companion applications discussed above or may otherwise by connected through other electrical connector means such as cabling or male connectors 102 and female connectors 104 for connecting adjacently placed modules as shown in FIG. 3.

The diaphragm may be suitably attached to the inside surface of the enclosure by way of adhesives such as a cyanoacrylate adhesive 106 or can be held in place by way of a suitable mechanical clamp 108. Similarly, the filter element 86 can be attached by way of an cyanoacrylate adhesive or other suitable means.

Typically the transparent front face portion 60 will be a plastic material such as a polycarbonate or other materials known in the art. Paint 112 may be suitably provided to the transparent piece 114 such as by silk screening to form the front face portion. Suitably portions would be left unpainted from the windows 116 as shown in FIGS. 2, 4, and 5.

As shown in FIG. 2, an additional sheet 120 of latex material may be added intermediate the circuit board 62 and the back panel 122 to provide further moisture protection and some cushioning protection for the circuitry and light emitters .

The transparent front face portion is suitably attached with adhesive and may be supplementally sealed such as by a silicon sealant. Ideally the seal will provide a hermetically sealed enclosure with the flexible membrane providing pressure equalization between the first chamber and the second chamber. Such pressure equalization is particularly important where the transparent front face portion is made of a thin flexible plastic material which can bow significantly if the pressure equalization means are not provided.

Referring to FIGS. 6 and 7, alternate means for minimizing deflection of the front face portion are shown. The front face portion has additional reinforcing structure 120 to provide rigidity. Additionally, the module is configured such that it attaches to a mounting structure 36 at the enclosure ' s periphery 142 and the back panel 144 is flexible enough such that it can flex as indicated by the dashed lines 147 thereby relieving the potential buildup of an interior-exterior pressure differential. The back panel is configured to substantially less rigid than the front face portion whereby the back panel flexes rather than having any significant deformation of the front panel. The enclosure is configured such that bowing or flexing of the rear panel does not affect the engagement of the module with the mounting structure nor with the electrical connections.

Opaque material may be added within the individual recesses 158 to minimize light crossover between adjacent pixels .

Thus the means of minimizing the deflection of the front face portion include providing greater rigidity to the front face portion, building in flexibility in portions of the enclosure other than the front face portion and utilizing a diaphragm or billows to divide the open interior into two chambers .

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Claims

WE CLAIM :

1. An outdoor sign comprising a support structure and a plurality of sign modules connected to the support structure, the sign modules arranged next to one another defining a sign screen, each module comprising:

a weather resistant sealed enclosure comprising a transparent front face portion and a base_. ortion defining an open interior;

a plurality of heat generating light emitting elements contained within the enclosure adjacent to said transparent front face;

a membrane comprised of a flexible sheet material separating the open interior into a first chamber and a second chamber, the second chamber vented to the exterior of the module, the first chamber defined in part by the transparent front face portion and being hermetically sealed with respect to the exterior of the module, the membrane moveable in response to varying pressure differentials between the first and second chamber whereby the pressure in the first chamber is equalized with the pressure at the exterior of the module.

2. The outdoor sign of claim 1 wherein the second chamber is defined by a protruding portion defining a recess in the interior of the enclosure, said protruding portion extending outwardly from the base portion.

3. The outdoor sign of claim 2 wherein the membrane comprises a diaphragm extending across said recess.

4. The outdoor sign of claim 1 wherein the membrane is configured as a volumetrically expandable sac.

5. The outdoor sign of claim 1 further comprising a filter in the vent .

6. A display module for a changeable message sign, the module comprising:

a sealed enclosure having an open interior and a planar front panel with an inside surface;

a plurality of pixel elements positioned in the open interior adjacent the front panel and viewable therethrough, the pixel elements changeable; and

a flexible membrane having a first surface and a second surface and positioned in the open interior, the inside surface of the front panel and the first surface of the membrane defining a first chamber, the second surface of the membrane defining a second chamber, the second chamber vented to the exterior of the sign module, the flexible membrane moveable whereby the pressure in the first chamber is equalized with the pressure in the second chamber thereby preventing bowing of the front panel due to pressure differentials between the interior and exterior of the sealed enclosure.

7. The display module of claim 6 wherein the enclosure has an outwardly protruding portion defining a recess in the interior of the enclosure, the flexible membrane extending across and covering said recess.

8. The display module of claim 7 wherein the membrane is comprised of a flexible resilient material.

9. The display module of claim 6 further comprising a filter at the vent .

10. The display module of claim 9, wherein the enclosure is formed from thermoplastic.

11. A display module for a changeable message sign, the module comprising:

a hermetically sealed enclosure having an open interior and a planar transparent front panel with an inside surface;

a plurality of light emitting sources positioned in the open interior adjacent the transparent front panel, the light emitting sources controllable by a sign controller; and

a means for minimizing deflection of the transparent front panel due to pressure differentials between the interior and exterior of the sealed enclosure.

2. An outdoor sign comprising:

a support structure;

a weather resistant sealed enclosure comprising a transparent front face portion and a base portion defining an open interior; said enclosure at least six inches in height and six inches in width;

a plurality of pixel elements contained within the enclosure adjacent to said transparent front face portion; and

means for minimizing deflection of the transparent face portion.

13. The outdoor sign of claim 12, wherein the sealed enclosure is comprised principally of thermoplastic.