Abstract:
Architecturally aesthetic signage having a sufficient hardness that upon interaction with an etchent results in a plurality of smooth tiers or terraces resulting in both visual and tactile indicia for communication with an observer is disclosed. In the preferred embodiment, the tactile and visual indicia comply with the requirements of the Americans for Disabilities Act. The signage is preferably formed by an etcher system including: an etchent delivery; an etchent; a substrate holder; a substrate having sufficient hardness that upon interaction with the etchent produces the visual indicia for communication with an observer; and a controller for controlling the delivery of the etchent onto the substrate to form the signage.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    (1) Field of the Invention  
           [0002]    The present invention relates generally to signage and, more particularly, to a method and apparatus for producing raised signage that meets the requirement of the American for Disabilities Act.  
           [0003]    (2) Description of the Prior Art  
           [0004]    Architectural signage communicates to an observer through its context whether it is visual or written. It is important for signage to contain an aesthetic aspect in that the visual or aesthetic component adds to presenting the message at hand either for the particular point to be made or within the context of an environment. In 1992 the Federal Government passed the Americans for Disabilities Act (ADA), which created additional challenges in the design of architectural signage. In particular, the ADA has specific requirements that challenge the designer. Among these requirements are:  
           [0005]    “ . . . letters and numbers shall have a width to height ratio between 3:5 and 1:1 and a stroke-to-height ratio between 1:5 and 1:10; character height, as sized according to the viewing distance . . . 0.032″raised lettering not less than {fraction (5/8)}″height, no higher than 2″; and symbols in their own 6″ high field and accompanied with Grade II Braille. Braille dot diameter 0.059″, inter-dot spacing 0.090″, horizontal separation between cells 0.241″, vertical separation between cells 0.395″. Characters and background of sign shall be an eggshell or matte (non-glare) finish. Characters shall meet a minimum 70% contrast to background.” 
           [0006]    The ADA specifically requires that with respect to signage, the alpha numerical text and symbols printed on the signs must be formed to comply with certain size and viewing distance requirements. In particular, the text and characters nust be in relief, i.e. projecting from the surface of the signage, in order to comply. This construction and arrangement enables those with limited eyesight to discern or finger trace the signage and the messages conveyed, as well as enable the blind to read Braille characters of the signage. In this sense, the ADA requires that in public places as well as certain private locations, that signage communicate to people having visual imparities such as partial blindness and total blindness. The designer is thus challenged to communicate to the seeing, the partially blind, and the totally blind. Further, the designer is challenged to communicate to the literate and illiterate of these groups. To accomplish this, the designer wants to clearly communicate to all groups in a way that does not create distractions for any one group.  
           [0007]    Businesses have attempted various approaches in making signage to meet ADA requirements. One technique includes enameled metals. Other techniques use photopolymers. These materials have been found to be particularly advantageous in that they allow the creation of tiered surfaces including a sharp contrast between the background and the symbolic indicia. A major drawback of such signage is that the same chemistry or technology that allows the creation of unique and architecturally aesthetic signage is its weakness. That is, photopolymers are susceptible to environmental factors such as environmental chemistry, radiation and thermophysical fluctuations.  
           [0008]    With respect to environmental chemistry, the acid compounds in air pollution are known to adversely effect polymers and even more so, photopolymers. With respect to radiation, the manufacturing advantage and flexibility of using radiation to create objects from photopolymers works to their detriment when exposing the resultant objects to solar radiation, including ultraviolet radiation that can result in the objects&#39; degradation.  
           [0009]    The thermophysical fluctuations of the environment include thermal cycling. This is particularly an issue in the application of signage in areas where there is a large variation in temperature, for example, the extreme northern and southern United States where the temperature varies from substantially below freezing to temperatures above 90° F. and even above 100° F.  
           [0010]    Another aspect of these photopolymers is their susceptibility to humidity, which may be a factor in chemical degradation, that may be an additive factor in that moisture can adversely affect these photopolymers.  
           [0011]    Thus, there remains a need for a new and improved signage that meets the requirement of the American for Disabilities Act which is environmentally stable while, at the same, reducing the labor, materials and maintenance costs of the signage. New and improved environmentally stable signage may withstand environmental factors such as environmental chemistry including acid compounds in air pollution, radiation including solar radiation and thermophysical fluctuations including thermal cycling discussed above. A new and improved method and apparatus for producing such environmentally stable signage has been developed.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention is directed to an environmentally stable, architecturally aesthetic signage. The signage comprising a substrate having sufficient hardness that upon interaction with an etchent results in a plurality of raised, smooth surfaces resulting in both visual and tactile indicia for communication with an observer that will survive longer in an outdoor environment. In the preferred embodiment, the tactile and visual indicia comply with the requirements of the Americans for Disabilities Act. Also, the tactile indicia corresponds to the visual indicia.  
           [0013]    In the preferred embodiment, the smooth surfaces are further tiered or terraced. The smooth surfaces may be a tier or terrace in the sense of a flat or open surface adjoining another surface, usually one of a layered series. The tier or terrace may create an effect in the signage where surfaces rise one above another via vertical or sloping steps. A tier or terrace may be a generally flat, long and narrow surface bordered on at least one side by a steep ascending or descending slope and, optionally, on the other side by a steep descending or ascending slope. In a preferred embodiment, a steep ascending or descending slope is substantially perpendicular to an adjoining surface. There may also be a first color coating on a first terrace and a second color coating on a second terrace. Preferably, the indicia includes lettering wherein the indicia is formed from a second color coating different from the first color coating and may further include a clear coat over at least the lettering portion of the signage.  
           [0014]    Also, in the preferred embodiment, the substrate is formed from a polymer. The polymer may include a filler, such as an oxide of aluminum such as aluminum trihydrate. Preferably, the particle size of the filler is large enough to permit etching and small enough to permit the formation of clear distinguishing smooth surfaces. The polymer may be an acrylic polymer, a polyester polymer or a methyl methacrylate polymer. One particularly suitable filled polymer is CORTAN® plastic sold by Dupont of Wilmington, Del. and, another is Carolite™ plastic sold by Carolina Custom Surfaces of Greensboro, N.C.  
           [0015]    Accordingly, one aspect of the present invention is to provide an architecturally aesthetic signage for complying with the requirements of the Americans for Disabilities Act, the signage comprising a substrate having sufficient hardness that upon interaction with an etchent results in a plurality of smooth surfaces resulting in both visual and tactile indicia for communication with an observer.  
           [0016]    Another aspect of the present invention is to provide an etcher system for forming a substrate for use in an architecturally aesthetic signage complying with the requirements of the Americans for Disabilities Act, the system comprising: an etchent delivery; an etchent; a substrate holder; a substrate having sufficient hardness that upon interaction with the etchent results in a plurality of smooth surfaces resulting in visual indicia for communication with an observer; and a controller for controlling the delivery of the etchent onto the substrate to form the signage.  
           [0017]    Still another aspect of the present invention is to provide a method for forming a substrate for use in an architecturally aesthetic signage complying with the requirements of the Americans for Disabilities Act, the method comprising the steps of: providing an etchent delivery; providing an etchent; providing a substrate holder; providing a substrate having sufficient hardness that upon interaction with the etchent results in a plurality of smooth surfaces resulting in visual indicia for communication with an observer; and controlling the delivery of the etchent onto the substrate to form the signage.  
           [0018]    These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a front view of signage produced according to the present invention;  
         [0020]    [0020]FIG. 2 is a cross sectional view of the signage in FIG. 1, taken along lines  2 - 2 ;  
         [0021]    [0021]FIG. 3 is a cross sectional view of the signage in FIG. 1, taken along lines  3 - 3 ;  
         [0022]    [0022]FIG. 4 is a cross sectional view of the signage in FIG. 1, taken along lines  4 - 4 ;  
         [0023]    [0023]FIG. 5 is a schematic diagram of an etcher system for producing raised signage shown in FIG. 1;  
         [0024]    [0024]FIG. 6 is a flow chart for a method for producing raised signage shown in FIG. 1; and  
         [0025]    [0025]FIG. 7 is a flow chart for a control system for controlling the etcher shown in FIG. 5. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as “forward,” “rearward,” “left,” “right,” “upwardly,” “downwardly,” and the like are words of convenience and are not to be construed as limiting terms.  
         [0027]    Referring now to the drawings in general and FIG. 1 in particular, it will be understood that the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto. As best seen in FIG. 1, signage, generally designated  10 , is shown constructed according to the present invention. The signage  10  includes a substrate  12  having communicative indicia  22  such as symbolic indicia  18 , tactile indicia  24 , and alphanumeric indicia  28 .  
         [0028]    The purpose of this signage  10  is to communicate, as in this specific example, the location of a Men&#39;s room including a handicapped access to any seeing, partially blind, and totally blind observer, whether literate or illiterate, in a way that does not create distractions for any one group. However, Applicants contemplate that any signage within a public or private facility that is regulated by the Americans for Disabilities Act is included in the present invention. For instance, signage for identifying room numbers, specifying locations of concessions, as well as including corporate logos or aesthetic artwork to add to the visual or aesthetic experience of the observer.  
         [0029]    Now referring to FIG. 2, it depicts the cross-sectional section of the signage  10  at location  2 . The cross section shows a substrate  12  coated with a first color layer  26  on a lower tier or terrace, an optional next level tier or terrace and an upper tier or terrace. An optional color layer  30  of a different color may be included on the optional next level tier to create, for example, a rim or shadow effect. The upper tier or terrace, which includes symbolic indicia  18  and alphanumeric indicia  28 , is covered with a second colored layer  32 . The second colored layer  32  used for alphanumeric indicia  28  may be the same as or different from the second colored layer  32  used for the symbolic indicia  18 . Both colors are different from that of the first color layer  26 . The entire surface of the signage  10  is then covered with a clear coat  34 . The selection of the color for the first color layer  26  and the optional color layer  30  may be such to add aesthetic features to the signage  10 . The selection and placement of the color of the second colored layer  32  on the first color layer  26  is such as to meet the requirements of the Americans for Disabilities Act and, more importantly, communicate the information of signage  10  to any seeing, partially blind, and totally blind observer, whether literate or illiterate, in a way that does not create distractions for any one group.  
         [0030]    The function of clear coat  34  is to provide protection to first color layer  26 , optional color layer  30 , and the second colored layer  32  to extend the signage life. Similar features are depicted in FIGS. 3 and 4, which are cross sections at locations  3  and  4  of signage  10  depicted in FIG. 1. Note that the tactile indicia  24  of the figures is not solely the Braille lettering but may also include symbolic indicia  18  and alphanumeric indicia  24 . Coloring the Braille lettering is optional in that the communication is via its touch and feel, and it may be better to not color the Braille lettering so as no to distract the seeing observer.  
         [0031]    The lettering depicted in signage  10  is of a size to be seen by those with visual impairments such as the partially blind. In addition, it is beneficial for the lettering to have a distinct step from the lower tier or terrace to the upper tier or terrace. This provides an additional method for the visually impaired to verify the content of the signage. Such persons, while being Braille illiterate, may be able to touch the lettering to make out what the letters are to gain an understanding or clarification of the signage  10 .  
         [0032]    To create signage  10  according to the present invention it is beneficial to use a substrate  12  that is not adversely affected by the environmental effects discussed above. In particular, it is beneficial to use a substrate  12  that is resistant to the environmental chemical aspects to an environmental thermophysical variation, as well as environmental radiation. In particular, the substrate  12  material would be of the type that is not adversely affected by ultraviolet radiation. In the case that the signage may be used in a facility including other manmade radiation sources, such as medical and chemical diagnostics equipment that includes x-ray radiation, nuclear magnetic radiation, and other forms of photon or electron radiation, the substrate  12  would be selected in way to survive these environments.  
         [0033]    In regard to the substrate  12 , it is selected to have a hardness that allows it to be processed in an etching technique that results in signage having communicative indicia that is relieved from the surface to meet the requirements of the Americans for Disabilities Act. Applicants have found that polymer substrates work well even though photopolymer substrates do not. The polymer of the substrate  12  may be a matrix  14  for holding a filler  16 . Particular types of polymers that Applicants have found to work well include polyester polymers, acrylate polymers and, particularly, methyl methacrylate polymers. Good filler materials within the polymer include oxides, particularly, oxides of aluminum such as aluminum trihydrate. More details concerning polymer systems that may be suitable for use in the present invention are discussed in, for example, U.S. Pat. Nos. 6,004,663; 5,882,560; 5,807,954; 5,747,154, 5,708,066; 5,662,846; 5,286,290; 5,272,230; 5,252,644; 5,250,596, 5,243,003; 5,145,903; 5,134,210; 5,073,587; 4,722,960; 4,678,819; 4,643,921; 4,413,089; 4,246,163; 4,183,991; 4,159,301; 4,107,135 and 3,847,865, the entire disclosure of each being hereby incorporated by reference herein. One particularly suitable filled polymer is CORIAN® plastic sold by Dupont of Wilmington, Del. and, another is Carolite™ plastic sold by Carolina Custom Surfaces of Greensboro, N.C.  
         [0034]    An evaluation conducted and reported by DuPont Corian® Research and Development has examined the effects of chemical exposure to Corian® to help define its limits for use in chemical laboratories. Several samples of Corian®, including light and dark colors, were tested with 20 chemicals for surface damage effects. In addition, samples were also exposed to some of the harshest reagents and tested for changes in mechanical strength (flexural properties), impact resistance and surface hardness.  
         [0035]    Surface Exposure to Chemical Reagents  
         [0036]    A chemical spot test procedure similar to ANSI Z124.6 Section 5.2 was used to evaluate the chemical resistance of Corian®. Several drops of each reagent were placed on the surface covered under a watch glass and left overnight (approximately 16 hours). The Table 1 lists reagents used, their effect on Corian® the surface.  
                         TABLE 1                           Chemical Testing and Performance            Reagents   Effect on Corian ®               Acids:   No effect       10% acetic acid   No visible surface change       0.10 M nitric acid (HNO 3 )       0.10 M hydrochloric acid (HCl)       Bases       0.10% sodium hydroxide       concentrated ammonium       hydroxide       Oxidizers       Concentrated sodium       hypochlorite       15% sodium hypochlorite       Bases   Slight       10% sodium hydroxide   Barely visible       Solvents   deglossing of surface       Carbon tetrachloride (CCl 4 )       Acetone       Toluene       Acids   Moderate       10.M nitric acid   Visible deglossing or slight etching       Bases       *50% sodium hydroxide       Solvent       methyl ethyl ketone       Acids   Pronounced       *glacial acetic acid   Surface change with slightly raised or           moderate etching       Solvent       chloroform (CHCl 3 )       methyl methacrylate       Acids   Very Pronounced       *aqua regia   Significant raised or etched surface       *11 M nitric acid (HNO 3 )       10 M hydrochloric acid (HCl 3 )       Solvents       Methylene chloride (CH 2 Cl 2 )                       # health and safety requirements.           
 
         [0037]    General Conclusions from the Chemical Exposure Test:  
         [0038]    Corian® is resistant to strong bases.  
         [0039]    Corian(® was not affected by the oxidizing agent tested.  
         [0040]    Strong acids can effect the surface of Corian® if left on the surface. There is little or no effect if cleaned up within a reasonable time (15-20 minutes).  
         [0041]    Organic solvents such as methylene chloride (CH 2 Cl 2 ), chloroform (CHCl 3 ) or methyl ethyl ketone (MEK) can produce significant surface marring if left on the surface. With long exposure to very strong acids and some solvents, the surface of Corian® can be significantly etched, softened or raised and will require sanding and buffing to renew the surface. It is most likely that strong acids would be used with extreme care, but organic solvents are used more liberally and could limit the use of Corian® in some labs. The best practice is to install a test piece of material to confirm the suitability of Corian® for the application.  
         [0042]    Mechanical Testing  
         [0043]    To quantify the practical risk of chemical exposure to the mechanical integrity of a Corian® installation, several tests were performed. Pieces of Corian® were subjected to simulated spills of three chemicals: 1.0M nitric acid, methylene chloride, and acetone. Ten milliliters of each reagent was placed on the surface, the spill was covered with a plastic lid, and the lid was weighted. These samples were left overnight and tested the following day.  
         [0044]    Impact Strength  
         [0045]    The impact resistance of the materials was tested using the ball-drop test. The test materials and a control were supported on a metal frame prescribed by the ASTM Z3029 procedure. The test was continued to a maximum impact of 4 lbs.×10 feet. In all cases, we were unable to break the samples. It was found that all the samples performed equal to control, so the chemical spills did not affect the bulk impact resistance.  
         [0046]    Impact strength After the surface was marred by chemical exposure, the samples were milled to provide INSTRON test bars. In this process, the damaged area was milled off so the observed mechanical properties represent any change to the “internal” integrity of the Corian®. All samples were equal to control, again confirming that the bulk properties were not affected by the spills.  
         [0047]    Surface hardness The surface hardness showed clearly the effects of chemical attack. HNO 3  (1.0 molar) did not significantly lower the hardness. The acetone had some effect, but would only require buffing with a Scotch-Brite pad to remove all marring. Methylene chloride had the greatest effect, as expected. However, when the sample was lightly sanded, as it would be to renew the appearance, the hardness of the fresh surface was equal to that of the control.  
         [0048]    The properties of Corian® plastic make it suitable for environmentally stable signage able to withstand chemically and/or physically harsh environments. New and improved environmentally stable signage may withstand environmental factors such as environmental chemistry including acid compounds in air pollution, radiation including solar radiation and thermophysical fluctuations including thermal cycling discussed above. Also, these properties permit the formation of integral tactic indicia. Furthermore, the properties permit the formation of substantially perpendicular ascending and descending side between terraces. Applicants believe that Carolite™ plastic possess similar characteristics.  
         [0049]    The combination of the size and amount of the filler within the polymer matrix  14  is such that it permits the use of the substrate  12  in the etching process to create the indicia that is distinguished from the background. This is particularly important with respect to the tactile indicia  24 . The size, shape and distribution of the filler  16  is such that the tactile indicia  24  communication of the signage is not confused or obfuscated by the presence of roughness due to the filler  16  within the polymer matrix  14 .  
         [0050]    Applicants believe that the signage  10  of the present invention may be made by using numerous techniques or equipment and have found that the technique using an etcher  40  is beneficial. The substrate  12  having the properties that are desirable for the resultant signage is placed in the substrate holder  46 . The etchent delivery  42  may include a nozzle  54  for directing the etchent  44  such as a pressurized fluid onto the surface of the signage  10 . To create the visual indicia  22  on the signage  10 , a mask  20  is placed onto the substrate  12  surface to protect the surface from the etchent  44 . The etchent  44  is then directed to the surface of the substrate  12  and in areas where there is no mask  20  the substrate  12  is etched, and in locations where there is a mask  20 , the substrate  12  is retained.  
         [0051]    An aspect of the present invention is that the impingement of the etchent  44  is substantially perpendicular to the surface of the signage  10  which creates a good step between the resultant background of the signage  10  and the communicative indicia  22  and  24 . The etchent  44  is delivered to the surface and as noted, it may be a pressurized fluid. Examples of pressurized fluids include a gas such as air. Applicants have found that by providing an abrasive grit  56  in air at a pressure of about 30 to about 40 pounds per square inch, good results are obtained. Abrasive grit  56  may also include oxides, which are known in the art. One type of oxide that Applicants have used includes an oxide of aluminum having a particle size of about 100 grit.  
         [0052]    To create the signage  10  according to the present invention there is relative movement of the etchent delivery  42  or nozzle  54  over the surface of the substrate  12  at a predetermined distance and speed such that the etching depth is substantially uniform over the substrate  12 . This creates clarity in the resultant signage  10 , and clarity in the sense that the communicative indicia including visual symbols, alphanumeric symbols and Braille are distinct from the background. To accomplish this, the movement of the etchent delivery  42  and the substrate holder  46  is performed along a major and a minor axis movement in a controlled way to be constant and consistent. The movement occurs as the etchent  44  is delivered and a movement mechanism  60  is used to accomplish this.  
         [0053]    The movement can be done either by the movement of the etchent delivery  42 , the movement of the substrate holder  46 , or the movement of both. Applicants have found that the spacing between the etchent delivery  42  and the substrate holder  46  is important as well as that the speed of the etchent delivery  42  is important. These factors are determined by the composition of the substrate  12 .  
         [0054]    To accomplish the desired results in the signage, a controller  50  can be included in the etcher  40 . The controller  50  can be of the type known in the industry. More details concerning a controller that may be used in etcher  40  are discussed in, for example, U.S. Pat. Nos. 5,980,078; 5,726,912; 5,689,415; 5,579,218; 5,351,200; 4,916,600; 4,344,127; and 4,646,223, the entire disclosure of each being hereby incorporated by reference herein. The etcher  40  in combination with the controller  50  might include mechanisms and provisions for regulating the pressure at which the etchent is delivered. This combination might also regulate and set the predetermined spacing  64  between the etchent delivery  42 , the substrate holder  46 , and, in particular, the substrate surface  12  for regulating and maintaining the speed of the relative movement of the etchent delivery  42  and the substrate holder  46 .  
         [0055]    Further, the etcher  40  may include a movement mechanism or mechanisms  60  to provide for the relative movement of the etchent delivery  42  and the substrate holder  46  along a major axis and a minor axis to regulate the consistent etching of the background to create the indicia in a signage. More details concerning a movement mechanism or mechanisms that may be used in etcher  40  are discussed in, for example, U.S. Pat. Nos. 5,872,892; 4,979,093; 4,835,710; 4,417,845; 4,352,620; and 4,068,156, the entire disclosure of each being hereby incorporated by reference herein. Finally, the etcher  40  and the controller  50  might include provisions for monitoring the depth and consistency of the etching to not only set a stop point but also to permit the consistent etching depth and also to permit the system to correct any problems that might have occurred in the etching process to create a consistently etched signage. More details concerning provisions for monitoring the depth and consistency of the etching that may be used in etcher  40  are discussed in, for example, U.S. Pat. No. 5,042,949, the entire disclosure of which is hereby incorporated by reference herein.  
         [0056]    [0056]FIG. 6 depicts a flow chart showing a method for making signage  10  according to the present invention. FIG. 7 depicts a flow chart showing a control method for making signage  10  according to the present invention. Although FIG. 7 shows serial processing of parameters, parallel processing as well as parallel together with serial processing is also contemplated. In an aspect of the present invention, first a design for signage  10  is obtained. The design may include alphanumeric information, as well as symbolic information. The artwork for these may be developed by using a computer system that might interface with the controller  50 .  
         [0057]    In operation, once the art is generated, the mask work  20  to be applied to the substrate  12  is generated and that mask work  20  is processed and placed on the substrate  12 . A suitable mask material is a yellow stencil mask (part # 802245) available from Accu-Cut Systems of Fremont, Nebr. The substrate  12  is then etched and cleaned. More details concerning equipment that may be used for etching are discussed in, for example, U.S. Pat. Nos. 3,407,539; 3,372,704; 3,307,296; 3,298,137; 3,286,406; 3,103,084; and Des. 246,108, the entire disclosure of each being hereby incorporated by reference herein. The etched and cleaned substrate  12  is then painted with a background color. Different technologies might be used to apply the lettering or indicia coloring to the alphanumeric or symbolic information. Different technologies that have been used include hot stamping and screen-printing. Finally, a clear coat  34  may be applied to the entire signage  10  to add an additional provision for protecting the signage  10  from environmental effects.  
         [0058]    Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.