WO2006074544A1

WO2006074544A1 - Fireplace assemblies with antireflective screens

Info

Publication number: WO2006074544A1
Application number: PCT/CA2006/000034
Authority: WO
Inventors: Donald R. Jamieson
Original assignee: Cfm Corporation
Priority date: 2005-01-12
Filing date: 2006-01-12
Publication date: 2006-07-20
Also published as: CA2532616A1; US20060150966A1

Abstract

Fireplaces including antireflective screens are provided. The antireflective screens can include a glass sheet with an antireflective agent attached to or forming a surface of at least a portion of the glass sheet. A low-emissivity agent can also be attached to or form a surface of at least a portion of the glass. In addition, light diffusing screens for displaying simulated flames in simulated fireplaces are provided. The light diffusing screens can include an antireflective agent attached to or forming a surface of at least a portion of the light diffusing screens.

Description

FIREPLACE ASSEMBLIES WITH ANTIREFLECTIVE SCREENS

This application claims the benefit of U.S. Provisional Application No. 60/643,272, filed January 12, 2005.

FIELD OF THE INVENTION

The subject invention relates to fireplaces that include an anti reflective screen through which to view the interior of the fireplace. The subject invention also relates to simulated fireplaces that include an antiref lective light-diffusing screen for displaying simulated flames.

BACKGROUND OF THE INVENTION

Fireplaces, including wood-burning, gas-burning, and electric simulated fireplaces are installed in most homes in at least the United States and Canada, and, indeed, many other areas of the world. In addition, portable fuel-burning and electric fireplaces are widely used to provide portable heat sources that can be used both outdoors and indoors, provided that the portable fuel-burning fireplace uses a clean-burning fuel such as propane or kerosene.

Historically, the fireplace functioned primarily to heat the room or home in which it was installed, and thus the appearance of the fireplace interior was unimportant, if not generally considered unsightly due to the accumulation of ash and soot therein. With respect to simulated fireplaces, relatively unimpeded viewing of the fireplace's interior was considered undesirable due to the poor quality of the simulated logs and ember bed installed within the simulated fireplace. As such, with the advent of glass screens on the front of fireplaces, efforts were undertaken by fireplace manufacturers to obscure relatively unobstructed viewing of the fireplace's interior to minimize the undesirable aesthetics of ash and soot, or conspicuously artificial logs and embers. Such obscuring was often times accomplished by tinting the glass so that the real or simulated fire and embers within the fireplace were only vaguely discemable from the outside. Lately, with advances in producing realistic simulated logs and embers, and with the growing popularity of clean-burning wood and gas fireplaces, it has become desirable to provide a clear view of the interior of the fireplace. One problem encountered, however, is that the cost-effective glass used to construct the front screen has an unacceptably high amount of glare and reflection from the ambient light in the environment in which the fireplace is installed. Examples of such environments include interior locations — including rooms of a dwelling — and exterior locations — including patio or garden locations. Some fireplace manufacturers have attempted to solve the reflection and glare problem by using ceramic glass, which inherently inhibits reflection and glare. Compared with other types of glass suitable for use in connection with fireplaces, however, ceramic glass is expensive, thereby increasing the overall price of the fireplace unit and, by extension, decreasing the ability of the fireplace manufacturer to compete in the market for affordable fireplaces. In addition, use of ceramic glass alone still results in a certain amount of undesirable reflection and glare, and thus it is not itself a satisfactory solution to the reflection and glare problem. Moreover, ceramic glass does not have a smooth and even surface, and thus images viewed through ceramic glass tend to be distorted.

It is known that at least one manufacturer has reduced some of the glare on a fireplace glass screen by directly attaching a mesh or woven wire screen to the glass screen. These glass screens with mesh or woven wire are intended to simulate the appearance of woven fireplace screens commonly found in many home fireplaces, while reducing reflection and glare off of the glass screen by providing an opaque matrix on the exterior surface of the glass. This approach is disadvantageous in that the opaque layer attached onto the front surface of the glass screen blocks the visibility of the interior of the fireplace. Also, the addition of an additional opaque layer to the surface of the glass screen introduces another costly and cumbersome step to the process of manufacturing the fireplace, and, therefore, raises the price of the fireplace.

Certain simulated fireplaces have light-diffusing screens installed in the rear of the firebox through which images of simulated flames are projected. At the same time, typical simulated fireplaces are intended to illuminate simulated ember beds and logs within the firebox. Such illumination of the simulated embers and logs creates glare and reflection on the diffusing screen that interferes with the image of the projected simulated flames. In the past, the problem was addressed by painting areas of the diffusing screen that were not critical to displaying the simulated flames with, for example, matte black paint. However, this treatment was not aesthetically pleasing, and it required yet another step in the process of manufacturing the simulated fireplace.

There is a demand, therefore, for a cost-effective, substantially- transparent screen that permits the largely unhindered view of the interior of a fireplace by reducing the amount of reflection and glare caused by ambient light outside the fireplace. There also exists a demand for a light diffusing screen for use in simulated fireplaces that reduces the amount of reflection and glare caused by the light reflected from the simulated embers. The present invention satisfies the demand.

SUMMARY OF THE INVENTION

The present invention is directed to a fireplace having a substantially transparent antireflective screen. For purposes of this application, the term "fireplace" means any interior or exterior or portable unit by which heat may be generated for environmental control purposes, including fuel-burning and electric fireplaces. For the purposes of this application, the term "antireflective screen" means a substantially transparent antireflective element or combination of elements through or by which the view that a viewer external to the fireplace has of the interior elements of the fireplace is generally not hindered by glare or reflection. For the purposes of this application, the term "light-transmitting member" means any transparent or translucent material capable of transmitting light therethrough, and to portions of which an anti reflective agent can be attached.

In preferred aspects, the present invention includes a fireplace assembly that includes a firebox. The firebox includes a top wall, bottom wall, back wall, and two side walls. The walls of the firebox define a firebox interior and an opening to the firebox interior. A substantially transparent screen that includes a first side and an opposed second side is disposed in the opening. In addition, an anti-reflective agent is attached to at least a portion of the first side of the screen.

In other preferred aspects, a light-diffusing screen for displaying a simulated flame in a simulated fireplace that has a flame-simulating assembly is disclosed. The light-diffusing screen includes a light-transmitting member that includes a first side and an opposed second side. In addition, an ^! antireflective agent is attached to or forms a surface of at least a portion of the first side.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a perspective view of a fireplace;

FIG. 2 illustrates a side view of a fireplace; FIG. 3 illustrates a perspective view of a simulated fireplace; FIG. 4 illustrates a side view of a simulated fireplace; FIG. 5 illustrates a cross section of an embodiment of an antireflective screen;

FIG. 6 illustrates a cross section of another embodiment of an antireflective screen;

FIG. 7 illustrates a cross section of another embodiment of an antireflective screen; FIG. 8 illustrates a cross section of another embodiment of an antireflective screen; and FIG. 9 illustrates a cross section of another embodiment of an anti reflective screen.

DETAILED DESCRIPTION OF A PRESENTLY PREFERRED EMBODIMENT

5 The present invention relates generally to a wide range of fireplaces including therewith substantially transparent front screens. The present invention will find application in all types of fireplaces without regard to the substances intended to be burned therein, and without regard to whether the fireplace is fuel-burning or electric. Without limiting the application of the io scope of the invention, the following will describe certain preferred embodiments used in conjunction with wood-burning and simulated fireplaces.

As best shown in Fig. 1 , one embodiment of the present invention includes a fireplace assembly 10 (or fireplace) that includes an antireflective screen 22 through which logs 36 and flames 38 in the interior of the fireplace

15 10. may be viewed. As best shown in Fig. 5, one embodiment of an antireflective screen 522 is preferably constructed of a sheet of tempered glass 523 with a substantially transparent antireflective agent 525 attached to or forming one side, in this example a first side 97, on a surface of the glass 523 facing away from the interior of the fireplace. In this embodiment, as in

20 other embodiments of the antireflective screens disclosed herein, the glass is constructed of a suitably heat-resistant and transparent glass, such as, without limitation, soda-lime tempered glass, borosilicate glass, or ceramiG glass. In a preferred embodiment for use in conjunction with fuel-burning fireplaces, soda-lime tempered glass or borosilicate glass is preferable

25 because it generally includes relatively low cost and even surfaces as compared to ceramic glass. However, one skilled in the art will readily recognize that other types of glass may be used so long as the glass exhibits suitably heat-resistant and transparent qualities necessary for incorporation within a fireplace unit. With respect to embodiments having screens used for

30 viewing the interior of simulated fireplace units, on the other hand, the glass need not be able to withstand relatively high temperatures because such glass is subjected to relatively low temperatures when used in a simulated fireplace.

There exist numerous anti reflective agents suitable for inclusion in embodiments of a fireplace assembly having an anti reflective screen. For example, antireflective agent 525 can be magnesium fluoride or silicone dioxide. However, one skilled in the art will readily recognize that other types of antireflective agents can be attached to or form a surface of the glass 523 so long as the antireflective agent 525 is substantially transparent and reduces the reflection of ambient light off of the glass 523 onto which it is attached or forms a surface. The antireflective agent 525 may be attached to or form a surface of the glass 523 by sputter coating the antireflective agent 525 onto the glass 523; dipping the glass 523 into a pool of antireflective agent 525; or spraying the antireflective agent 525 onto the glass 523.

The antireflective agent 525 can further be attached to or form an outer surface of some or all of a surface of the glass 523 depending on how much and which areas of embodiments of the screen 522 are determined to require an antireflective property. In addition, a protective layer of silicon dioxide (not shown) can be attached over the antireflective agent 525 to the screen 522 to increase the durability and longevity of the antireflective agent. The antireflective screen 522, as well as the other embodiments of antireflective screens discussed herein, may be obtained directly from the glass manufacturer, and thus do not require additional manufacturing steps beyond what was previously required by fireplace manufacturers to install a glass screen within a fireplace assembly. As shown in Fig. 6, another embodiment of the antireflective screen

622 may include a plurality of antireflective agents 625, 627 in conjunction with the glass 623. In this embodiment, antireflective agent 625 is attached to or forms a surface of the glass 623, and antireflective agent 627 is attached to or forms a surface of antireflective agent 625. In this example, moreover, the antireflective agents 625, 627 can be magnesium fluoride and silicone dioxide respectively, or vice versa. And, as previously explained, one skilled in the art will readily recognize that other antireflective agents may also be used.

As shown in Fig. 7, another embodiment of the antireflective screen 722 can include a plurality of antireflective agents 725, 727 attached to or

5 forms a surface of a first or outward facing side 97 of the glass 723, and a low-emissivity agent 729 attached to or forms a surface of an opposed inward facing side or second side 99 of the glass 723. The low-emissivity agent 729 functions to reduce the amount of heat transferred to the glass 723 by the burning fuel within the fireplace, and thus the low-emissivity coating 729 io preferably faces the interior of the fireplace when the screen 722 is installed within, for example, the fireplace 10 shown in Fig. 1. The low-emissivity agent 729 is typically a layer of tin oxide, though one skilled in the art will readily recognize that other substances can also be used. And although the low- emissivity agent 729 is shown in conjunction with a plurality of antireflective

15 agents 725, 727 attached to or forming a surface of the first side 97 of the glass 723, embodiments of the antireflective screen may include the low- emissivity agent 729 used with as few as one type of antireflective agent 725 attached to the second side 99 of the glass 723.

Figure 8 shows another embodiment of the antireflective screen. In

20 this embodiment, a plurality of layers of antireflective agents 825, 827 are attached to or form a surface of a first side 97 of the glass 823. In a preferred embodiment, another layer of antireflective agent 831 is attached to an opposed second side 99 of the glass 823, and a layer of low-emissivity agent 829 is further attached to or forms a surface of the layer of antireflective agent

25 831. As with other embodiments, the opposed second side 99 of the glass 823 having the low-emissivity coating 829 is preferably installed in the fireplace assembly such that the low-emissivity coating 829 faces the interior of the fireplace. Also, the positioning of the low-emissivity agent 829 and the antireflective agent 831 may be reversed in certain embodiments; however,

30 the gasses generated by burning fuel within the firebox may tend to degrade the antireflective agent 831 over time. Accordingly, in certain applications, the preferred embodiment includes the low-emissivity agent 829, as attached over or forming a surface of the antireflective agent 831.

As best shown in Figs. 1 -2, embodiments of the fireplace assembly 10 further includes a housing having a top panel 12, side panels 14, a rear panel 13, a bottom panel 17, and a front panel 19. Typically, the fireplace housing is constructed of sheet metal and the like. Formed through the front panel is an opening 20, into which are mounted two frames 24 that each hold an antireflective screen 22. The frames 24 are typically mounted in the opening 20 by way of hinges (not shown) that allow them to swing open, thereby providing access to the interior region 34 of the fireplace, also called the firebox.

In this embodiment, the firebox 34 is the chamber in which wood 36 or other combustible fuel is burned during operation of the fireplace 10. The firebox generally includes a top wall 28, bottom wall 32, a rear wall 30 and two side walls (not shown), all of which are disposed within the housing of the fireplace assembly 10. The firebox 34 is further attached to an air intake vent 27 for providing oxygen to the burning fuel 36, and an exhaust vent 40 foe exhausting the smoke and gasses from the firebox 34. The exhaust travels through exhaust vent 40, into plenum 42, and out exhaust 26 into a chimney (not shown) for release outside the building.

As previously described, the antireflective screen 22 can be constructed of glass with an antireflective agent attached to or forming a surface of the exterior surface 97 of the glass, as is shown in, for example, Fig. 5. During normal operation of the fireplace 10, ambient light 44, such as that generated by incandescent light bulbs or sunlight - such as through a window and to which generic reference is made, in the attached drawings with the number "44" -, may and often will be present in the room or context in which the fireplace 10 is installed. The ambient light 44 may shine light towards the antireflective screen 22 in a direction generally indicated by line B and strike the antireflective screen 22. The antireflective agent or agents of the antireflective screen 22 function to reduce the amount of light reflected back off of the screen 22 as generally indicated by dashed line C. By reducing the amount of reflected ambient light, the antireflective'screen 22 allows light from the fire 38 within the firebox 34 (generally traveling in the direction of line A) to be more easily seen by viewers.

5 As best shown in Figs. 3 and 4, in another embodiment of the invention an anti reflective screen 122 can be installed in a simulated or electric fireplace assembly 110. As with the anti reflective screen 22 used in conjunction with fuel-burning fireplaces as shown in, for example, Figs. 1 and 2, the antireflective screen 122 of this embodiment permits viewing of the contents io of the firebox 134, which, in this embodiment, is a simulated firebox. As best seen in Fig. 4, the firebox 134 is positioned within the housing of the electric fireplace 110 and comprises a top wall 128, a bottom wall 132, and two side walls 136. A light diff user screen 130 defines the back wall of the firebox 134. In the embodiment shown, the firebox 134 extends from approximately the top

15 edge of a lower louver panel 119 to above the bottom edge of an upper louver panel 118.

An artificial log and ember set 126 is positioned in the bottom of the simulated firebox 134. As best seen in Fig. 4, the log and ember set 126 comprises one or more artificial logs 140 that are supported by an ember bed

20 142, and which are formed of, for example, molded ceramic fiber. The logs 140 are shaped and colored to simulate the appearance of actual logs of any type.. The ember bed 142 is shaped and colored to simulate the appearance of burnt and/or burning coals or embers. The artificial logs 140 sit on top of the ember bed 142, which is positioned on top of a metal grate and ember

25 support 146, which is in turn supported by the bottom panel 132 of the firebox 134.

As best seen in Fig. 4, a light source 148 for illumination of the artificial log and ember set 126 can be provided by one or more incandescent light bulbs 148 located beneath the bottom panel 132 of the firebox 134. Openings

30 (not shown) allow light provided by light source 148 to pass up through the ember bed 142 so as to illuminate the underside of certain portions of the artificial logs 140. Some of the light that illuminates the underside of the artificial logs 140 is redirected downwardly and back onto upper side of the ember bed 142. The illumination of the artificial logs 140 and the ember bed 142 creates the appearance that the logs 140 and the ember bed 142 are glowing, thereby simulating an actual wood-burning fire above a bed of burning coals or embers.

An additional source of light 150 can be provided to illuminate the upper side of the artificial log and ember set 126. As best seen in Hg. 4, an incandescent light bulb 150 may be mounted to the underside of the top panel 128 of the firebox 134 so as to illuminate the front and upper portions of the artificial logs 140 and the ember bed 142, and to provide illumination of the firebox side walls 136.

As previously discussed, embodiments of the simulated fireplace 110 can include a light diffuser screen 130 positioned at the back of the simulated firebox 134. The function of the light diffuser screen 130 is to create the appearance of realistic looking flames 138 arising or emanating from the artificial log and ember set 126. The light diffuser screen 130 can be translucent, or partially or wholly transparent, so that the simulated flames projected onto the back of the light diffuser 130 are visible from the front of the fireplace 110. The light diffuser screen 130 is positioned against the back of the log and ember set 126 so that the simulated flames 138 appear to be emanating from the artificial logs 140. The light diffuser screen 130 of the preferred embodiment is comprised of a bronze-tinted, transparent, acrylic panel that has been treated or combined with a light-diffusing material, such as a light-diffusing ink that can be silk-screened onto the acrylic panel. The diffusing material provides the surface on which the projected flames 138 become visible. In addition to the light diffuser screen 130, the flame simulation assembly comprises a light source 148, a light randomizer 152, a reflective panel 154, and a light filter screen 156. In operation, the light from the light source 148 is directed upwardly through the light randomizer 152 in a direction generally indicated by line D in Fig. 4. The light randomizer 152 may comprise a hollow cylinder or tube 158, which has numerous openings (not shown) to permit light from the light source 148 to pass through. Such embodiment of the cylinder 158 is rotated about its central axis by a motor (not shown), and, as the cylinder 158 rotates, the position, shape, and intensity of the light passing through and emanating from the cylinder 158 will change.

Light can emanate from the light randomizer 152 in a direction generally indicated by line E. Such light thereafter passes through a light filter screen 156, which extends across the width of the fireplace 110. Such light emanating from the light randomizer 152 and passing through the light filter screen 156 will generally move upwardly along the back of the light diffuser screen 130, simulating the movement of flames.

Similarly, light may emanate from the light randomizer in a direction generally indicated by line F and strike reflective panel 154, which deflects the light through the light filter screen 156 and onto the light diffuser screen 130, thereby multiplying the amount of light reflected and flame patterns 138 present on the light diffuser screen 130. The light filter screen 156 is preferably constructed of polycarbonate that includes opaque paint or the like applied in areas to affect the amount and pattern of randomized light passing through the light filter screen 156 to the light diffuser screen 130; however, one skilled in the art will readily recognize that other suitably light-transmitting materials positioned adjacent masking agents, such as fabric or paper, can also be used to form the light filter screen 156.

As previously explained, during operation of an embodiment of the fireplace 110, light is shined into the firebox 134 to illuminate the artificial log and ember set 126 and to illuminate the sidewalls 136 of the firebox 134. This light in the firebox 134 can be reflected onto the light diffuser screen 130, thereby reducing the realism of the simulated flames 138 projected thereon. As such, as best shown in Fig. 9, embodiments of the light diffuser screen 130 may be constructed of a light-transmitting transparent or translucent member 923 with an antireflective agent 925 attached to or forming a surface of all or a portion of a surface of a first side of the light-transmitting member 923. A diffusing agent 929, such as, for example, a light-diffusing ink, may be attached to or form a surface of all or a portion of an opposed second side of the light-transmitting member 923 by, for example, silk-screening the ink onto the light-transmitting member 923. Embodiments of the light-transmitting member 923 may be constructed of a transparent or translucent polycarbonate sheet, etched glass, or any other transparent or translucent substance suitable for displaying an image of simulated flames. The antireflective agent 925 may be magnesium fluoride or silicone dioxide. However, one skilled in the art will readily recognize that other types of antireflective agents can be attached to or form a surface of the light- transmitting member 923 so long as the antireflective agent 925 is substantially transparent and reduces the reflection of ambient light off of the light-transmitting member 923 onto which it is attached. In operation, embodiments of the diffuser screen 130 that include the antireflective agent 925 reduce the amount of light reflected from the illuminated artificial log and ember set 126 and illuminated sidewalls 136 to enhance the realism of the simulated flames 138.

While endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicants claim protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon. While the apparatus and method herein disclosed forms a-preferred embodiment of this invention, this invention is not limited to that specific apparatus and method, and changes can be made therein without departing from the scope of this invention, which is defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A fireplace assembly, comprising: a firebox, wherein said firebox defines a firebox interior and an opening to the firebox interior; a substantially transparent screen disposed in said opening, wherein said screen includes a first side and a second side opposite said first side; and an anti-reflective agent attached to or forming a surface of at least a side portion of one or both of said first side and said second side of said transparent screen.

2. The fireplace assembly of Claim 1 , wherein said anti-reflective agent includes magnesium fluoride.

3. The fireplace assembly of Claim 1 , wherein said anti-reflective agent includes silicone dioxide.

4. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is sputter coated onto said transparent screen.

5. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is dip coated onto said transparent screen.

! 6. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is sprayed onto said transparent screen.

7. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is attached to or forms a surface of all of said first side.

8. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is attached to or forms a surface of a portion, of said first side.

9. The fireplace assembly of Claim 1 , wherein said anti-reflective agent is attached to or forms a surface of at least a portion of said first side and is attached to or forms a surface of at least a portion of said second side.

10. The fireplace assembly of Claim 1 , further including a layer of silicon dioxide attached to or forming a surface of said transparent screen over said anti-reflective agent.

11. The fireplace assembly of Claim 1 , wherein said anti-reflective agent includes a plurality of anti-reflective agents.

12. The fireplace assembly of Claim 11 , wherein said plurality of anti-reflective agents includes a layer of magnesium fluoride and a layer of silicone dioxide.

13. The fireplace assembly of Claim 1 , further including a low- emissivity agent attached to or forming a surface of said second side of said transparent screen.

14. The fireplace assembly of Claim 13, wherein said low-emissivity agent is a layer of tin oxide.

15. The fireplace assembly of Claim 11 , further comprising an inside layer of anti- reflective agent attached to or forming a surface of said second side of said transparent screen and a low-emissivity agent attached to or forming a surface of said inside layer of anti-reflective agent.

16. The fireplace assembly of Claim 11 , further comprising a low- emissivity agent attached to or forming a surface of said second side of said transparent screen and an inside layer of anti-reflective agent attached to or forming a surface of said inside layer of low-emissivity agent.

17. The fireplace assembly of Claim 1 , wherein said firebox includes a top wall, a bottom wall, a back wall, and two side walls

18. A light-diffusing screen for displaying a simulated flame in a simulated fireplace having a flame-simulating assembly, comprising: a light-transmitting member having a first side and an opposed second side; and an anti reflective agent attached to or forming a surface of at least a portion of said first side of said light-transmitting member.

19. The light-diffusing screen of Claim 18, further including a light- diffusing agent attached to or forming a surface of said second side of said light-transmitting member.

20. The light-diffusing screen of Claim 18, wherein said light- transmitting member is transparent.

21. The light-diffusing screen of Claim 18, wherein said light- transmitting member is translucent.

22. The light-diffusing screen of Claim 19, wherein the light-diffusing agent includes a light-diffusing ink.

23. The light-diffusing screen of Claim 19, wherein the light-diffusing agent is attached to or forms a surface of all or a portion of said second side of said light-transmitting member.

24. The light-diffusing screen of Claim 18, wherein said anti- reflective agent is magnesium fluoride.

25. The light-diffusing screen of Claim 18, wherein said anti- reflective agent is silicone dioxide.