System and method for filtering electromagnetic and visual transmissions and for minimizing acoustic transmissions

• US 20030224182A1
• Filed: 05/28/2003
• Published: 12/04/2003
• Est. Priority Date: 05/28/2002
• Status: Active Grant

• Current Assignee: Astic Signals Defenses, LLC, Eastman Performance Films, LLC (Eastman Chemical Company)
• Original Assignee: Astic Signals Defenses, LLC
• Inventors: Simpson, Deron, Winckler, Lisa Y., Spraker, Ronald L.
• Granted Patent: US 6,859,310 B2
• Time in Patent Office: Days
• US Class Current: 428/437
• CPC Class Codes: B32B 17/10005 laminated safety glass or glazing
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B32B 2367/00 Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: Y10T 428/3163 Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.]

Abstract

The invention describes a system and methods for filtering electromagnetic and visual transmissions and for minimizing acoustic transmissions. Various combinations of UV, IR, and yellow-tinted filters are applied in various physical configurations to a transparent substrate such as a plastic film or glazing of a window for modifying selected wavelengths of electromagnetic radiation. For instance a light filter may have a multi-layered metallic sputtered stack having a relatively low sheet resistance. The combination of filters prevents or attenuates the passage of selected wavelengths through the substrate as needed to address security risks. The combination of filters is useful to prevent unauthorized data collection and information exchange from or within buildings or otherwise prevent such unauthorized data collection and information exchange from, for example, computer monitors or screens, personal digital assistants, and local area networks.

Claims

1. A transmission filtering system comprising:

a yellow film first filter;

said first filter having a light transmission at wavelengths below 450 nm of less than 50%; and

a second filter connected to said first filter, wherein said second filter is either;

a light filter (a) comprising a heat reflecting film and a metallic layer, or

a light filter (b) comprising a film having an IR transmission at wavelengths between 780 nm and 2500 nm of no more than 50%, or

a light filter (c) comprising a multi-layered sputtered stack having a sheet resistance of less than 4 ohms per square

whereby said filters are configured to attach to a substantially transparent subsurface, and whereby a combination of the filtering system and the subsurface causes a desired attenuation and filtering selected electromagnetic wavelengths, and whereby said dielectric of each dielectric layer has an index of refraction in the range of about 1.35 to 2.6.

2. The system of claim 1, wherein said combination of filter further comprises an IR absorbing filter.

3. The system of claim 1, wherein said electrically conductive metal layer of light filter (a) has at least the electrical conductivity of aluminum.

4. The system of claim 3, wherein said electrically conductive metal layer of light filter (a) is copper.

5. The system of claim 1, wherein said heat reflecting layer comprises a plurality of heat reflecting metal layers and a plurality of dielectric layers.

6. The system of claim 1, wherein said light filter (a) said two corrosion protection metal or metal alloy layers that sandwich the said electrically conductive metal layer to protect said electrically conductive metal layer from corrosion.

7. The system of claim 1, wherein said light filter (b) has a sheet resistance less than 4 ohms/square and comprises a film which exhibits a visible light transmittance of about 60-70% a visible reflectance of about 9%, a total solar transmittance of about 46% and a solar reflectance of about 22%

8. The system of claim 1 wherein said electrically conductive metal layer of the light filter (c) is a metal oxide having an index of refraction in the range of about 1.7-2.6;

and said IR reflecting metal of the light filter (c) is silver.

9. The system of claim 8 wherein the light filter (c) comprises an Ag/Ti or an Ag/Au sputtered stack on a transparent sheet, the sputtered stack having a sheet resistance less than 4 ohms/square.

10. The system of claim 9 wherein said Ag/Ti sputtered stack is made by sputter coating the following sequence of layers:

1) a layer of metal oxide,

2) a silver IR reflecting layer,

3) a protective sacrificial layer of titanium,

4) a layer of metal oxide,

5) a silver IR reflecting layer,

6) a protective sacrificial layer of titanium,

7) a metal oxide layer,

8) a silver IR reflecting layer,

9) a protective sacrificial layer of titanium,

10) a layer of metal oxide;

and wherein said Ag/Au sputtered stack is made by sputter coating the following sequence of layers onto said substrate or onto a transparent plastic sheet;

1) a layer of metal oxide,

2) a silver IR reflecting layer,

3) a layer of gold,

4) a layer of metal oxide,

5) a silver IR reflecting layer,

6) a layer of gold,

7) a layer of metal oxide,

8) a silver IR reflecting layer,

9) a gold layer, and

10) a layer of metal oxide.

11. The apparatus of claim 10, wherein said sequence of layers of said sputtered Ag/Ti stack is made by coating the following sequence of layers onto said transparent plastic sheet:

1) a layer of indium tin oxide about 30 nm thick,

2) a silver IR reflecting layer about 9 nm thick,

3) a protective sacrificial layer of titanium about 1 nm thick,

4) a layer of indium tin oxide about 70 nm thick,

5) a silver IR reflecting layer about 9 nm thick,

6) a protective sacrificial layer of titanium about 1 nm thick,

7) an indium tin oxide layer about 70 nm thick,

8) a silver IR reflecting layer about 9 nm thick,

9) a protective sacrificial layer of titanium about 1 nm thick, and

10) a layer of indium tin oxide about 30 nm thick;

and wherein said sequence of layers of said sputtered Ag/Au comprises the following sequence of layers coated onto said transparent plastic sheet;

1) a layer of indium tin oxide about 30 nm thick,

2) a silver IR reflecting layer about 9 nm thick,

3) a layer of gold about 1 nm thick,

4) an ITO layer about 70 nm thick,

5) a silver IR reflecting layer about 9 nm thick,

6) a layer of gold about 1 nm thick,

7) an ITO layer about 70 nm thick,

8) a silver IR reflecting layer about 9 nm thick,

9) a gold layer about 1 nm thick, and

10) an ITO layer about 30 nm thick.

12. The system of claim 1, wherein the combination further comprising a third light filter including one or more PET films with UV absorbers dyed therein in an amount to produce at least 2.4 optical density absorbance in each PET film;

13. The system of claim 1 wherein the combination furthers comprises a fourth filter having an IR transmission at wavelengths below 400 nm of less than 10%.

14. The system of claim 13, wherein the third filter has the wavelength transmission properties of FIG. 2

15. The system of claim 13, wherein the fourth filter exhibits a percent light transmission at 320 nm and 380 nm that is less than 1% of the transmission at 550 nm, and a percent light transmission at 400 nm that is less than 50% of the transmission at 550 nm

16. The system according to claim 1 further comprising a flexible transparent plastic sheet configured for attachment to a glazing of a window.

17. The system of claim 16, further comprising a glazing of a window.

18. The system of claim 17, wherein the system includes a single sheet configured to cover the glazing;

and the system further includes an opaque electrically conductive sealant applied so as to cover any exposed portions of the glazing not covered by the sheet.

19. The system of claim 16, wherein the system is configured for attachment to at least one of a screen, monitor, and other stand-alone devices.

20. The system of claim 1, the system being configured to form a containment system.

21. The system of claim 20 wherein an adhesive layer connects the plastic sheet to a glazing.

22. The system of claim 21 wherein visible air bubbles are substantially excluded between the plastic sheet and the glazing.

23. The system of claim 1, wherein the combination of filters minimizes flying glass fragments.

24. The system of claim 1 wherein the combination of filters are in the form of layers connected to a plastic sheet.

25. The system of claim 24 wherein an adhesive layer connects the plastic sheet to a glazing.

26. The system of claim 1 further comprising a color correcting layer.

27. An anti-surveillance security system comprising a flexible transparent sheet comprising:

an outer pressure sensitive adhesive for adhering the sheet to substantially planner surface, the system comprising;

a plastic film with UV absorbers therein;

a heat reflecting film having a metal/oxide stack coated thereon, the heat reflecting film having UV absorbers contained therein;

a plastic film having yellow dye impregnated therein; and

a pressure sensitive adhesive.

28. The system of claim 27 further comprising a safety film.

29. The system of claim 27 further comprising a hardcoat for protecting an exterior surface of said sheet.

30. The system of claim 27 further comprising a laminating adhesive connecting the films.

31. The system of claim 27 further including a release liner releasably secured to the pressure sensitive adhesive, whereby the sheet can be adhesively secured to the glazing of the window upon removal of the release liner.

32. A method for filtering electromagnetic, visual, and minimizing acoustic transmissions, comprising the steps of:

selecting a transparent substrate; and

configuring a combination of filters connected to the substrate for filtering passage of the transmissions as measured by a desired shielding effectiveness, the combination comprising a first filter having the electromagnetic filtering properties of a dyed thin polyester film and a second filter having the electromagnetic filtering properties of a polyester film with sputtered heat reflecting, conductive metal stack coating.

33. The method of claim 32, wherein said first filter is yellow-dyed.

34. The method of claim 32, wherein the combination further comprises a color correcting filter.

35. A transparent anti-surveillance security system comprising a transparent substrate and a combination of filters connected to the substrate;

the combination of filters being selected and configured to filter passage of selected electromagnetic wavelengths through the system, the combination of filters comprising;

a first filter having the electromagnetic filtering properties of a yellow-dyed thin polyester film; and

a second filter having the electromagnetic filtering properties of a polyester film with sputtered heat reflecting, conductive metal stack coating.

36. The system of claim 35 further comprising a third filter having the electromagnetic filtering properties of a thin, clear weatherable film and a heat reflecting film.

37. The system of claim 35 comprising a PET film with UV absorbers dyed therein in an amount to produce at least 2.4 optical density absorbance.

38. The system of claim 35, wherein the second filter comprises a conductive layer interposed between layers of corrosion resistant material.

39. The system of claim 35, wherein the second filter comprises Ag/Ti sputtered stack having as a sheet resistance less than 4 ohms/square, wherein said Ag/Ti sputtered stack comprises a plurality of layers on a transparent plastic sheet, said plurality of layers including:

1) a layer of indium tin oxide,

2) an IR reflecting layer, and

3) a layer of titanium.

40. The system of claim 35, wherein the second filter comprises an Ag/Au sputtered stack, wherein said Ag/Au sputtered stack has a sheet resistance less than 4 ohms/square and wherein said Ag/Au sputtered stack comprises a plurality of layers on a transparent plastic sheet, said plurality of layers including:

1) a layer of indium tin oxide,

2) an IR reflecting layer, and

3) a layer of gold.

41. The system of claim 35 further comprising an IR absorbing filter.

42. The system of claim 41, wherein the IR absorbing filter includes LaB₆.or antimony tin oxide.

43. The system of claim 35 further comprising said heat reflecting film including plurality of heat reflecting metal layers and a plurality of dielectric layers.

44. The apparatus of claim 43, wherein said heat reflecting film comprising one or more layers onto a transparent plastic film with UV absorbers dyed therein at 2.4 optical density absorbance, said layers including a layer of Ag/Cu alloy, a layer of indium metal, a layer of titanium metal and a layer of indium tin oxide.

45. The apparatus of claim 35 further comprising a flexible transparent sheet configured for attachment to a glazing of a window.

46. The apparatus of claim 45 further comprising a safety film adhered to said glazing.

47. The apparatus of claim 35 further comprising two of said combination of filters, said two combinations of filters being spaced apart from each other.

48. The apparatus of claim 47, wherein each of said spaced apart combination of filters is embedded in spaced apart layers of polyvinylbutyral wherein each polyvinylbutyral layer is sandwiched between layers of glass or plastic window glazing.

49. The apparatus of claim 47 further comprising:

an upper layer comprising a first outer glass sheet joined to a first of said spaced apart combination of filters by a layer of PVB; and

a lower layer comprising a second outer glass sheet joined to a second of said spaced apart combination of filters by a second layer of PVB,

wherein said first and second of said spaced apart combination of filters being adhesively secured to each other by a third layer of PVB or by an adhesive layer and wherein said third layer of PVB and said adhesive having a thickness which determines a distance between said spaced apart combination of filters.

50. The apparatus of claim 49 wherein said third layer of PVB or said adhesive is electrically conductive.

51. The apparatus of claim 49 further comprising a layer of PVB or adhesive between the two combinations, wherein the layer of PVB or adhesive is electrically conductive.

52. The apparatus of claim 35, wherein said substrate is configured as a tent.

53. The apparatus of claim 35, wherein said substrate is configured as a bag.

54. The apparatus of claim 35 further comprising a color correcting filter.

55. The apparatus of claim 54, wherein color correcting has a refracting index between about 0.6 and about 4 and an extinction coefficient for light in the visible range between about 1.5 and about 7.

56. The apparatus of claim 54, wherein the color correcting layer consist of indium.

57. The apparatus of claim 54, wherein the color correcting layer is gray.

58. The apparatus of claim 35, wherein said second filter is substantially intransitive between 400 and 450 nm.

59. A method for adapting a transparent substrate to prevent or attenuate the passage therethrough of selected electromagnetic wavelengths as needed for security, said method comprising the step of applying a visually transparent electromagnetic filter apparatus onto said substrate, said transparent electromagnetic filter apparatus comprising

a first yellow film inhibiting selected light transmissions;

and

a second film connected to said first film, wherein said second film is either;

a light filter (a) comprising a heat reflecting layer and an electrically conductive metal layer, or

a light filter (b) having an IR transmission at wavelengths between 780 nm and 2500 nm of no more than 50%, or

a light filter (c) which has a sheet resistance of less than 4 ohms per square and comprises a sequence of layers;

a dielectric layer/IR reflecting metal layer/dielectric layer or

IR reflecting metal layer/dielectric layer/IR reflecting metal layer.

60. A method for preventing the unauthorized collection of data encoded in electromagnetic transmissions which comprises filtering said transmissions through the combination of filters apparatus comprising

a first filter having the electromagnetic filtering properties of a yellow-dyed thin polyester film, and

a second filter having the electromagnetic filtering properties of a polyester film with heat reflecting, conductive coating.