Abstract

In order to increase the anticounterfeiting performance of interference security image structures, we propose to implement an active component using an electrochromic material. This novel device, based on metamerism, offers the possibility of creating various surprising optical effects, it is more challenging to duplicate due to its complexity, and it adds a second level of authentication. By designing optical filters that match the bleached and colored states of the electrochromic device, one can obtain two hidden images—one appearing when the device is tilted, and the other one disappearing when the device is colored under an applied potential. Specifically, we present an example of a filter that is metameric with the colored state of the electrochromic device, demonstrate how the dynamic nature of the device offers more fabrication flexibility, and discuss its performance. We also describe a design methodology for metameric filters based on the luminous efficiency curve of the human eye: this approach results in filters with a lower number of layers and hence lower fabrication costs, and with a lower color difference sensitivity under various illuminants and for nonstandard observers.

© 2011 Optical Society of America

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References

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    [CrossRef]
  7. P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
    [CrossRef]
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    [CrossRef]
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  12. S. K. Deb, “A novel electrophotographic system,” Appl. Opt. 8, 192–195 (1969).
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    [CrossRef]
  16. E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
    [CrossRef]
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    [CrossRef]
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2009 (1)

2008 (3)

2007 (2)

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “Dependence of the estimated diffusion coefficient of LixWO3 films on the scan rate of cyclic voltammetry experiments,” Solid State Ionics 178, 259–263 (2007).
[CrossRef]

A. Subrahmanyam and A. Karuppasamy, “Optical and electrochromic properties of oxygen sputtered tungsten oxide (WO3) thin films,” Sol. Energy Mater. Sol. Cells 91, 266–274 (2007).
[CrossRef]

2005 (1)

K.-W. Park, “Electrochromic properties of Au-WO3 nanocomposite thin-film electrode,” Electrochim. Acta 50, 4690–4693(2005).
[CrossRef]

2004 (3)

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

I. M. Lancaster and A. Mitchell, “The growth of optically variable features on banknotes,” Proc. SPIE 5310, 34–45(2004).
[CrossRef]

2003 (1)

C. G. Granqvist, E. Avendaño, and A. Azens, “Electrochromic coatings and devices: Survey of some recent advances,” Thin Solid Films 442, 201–211 (2003).
[CrossRef]

2002 (1)

P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
[CrossRef]

2001 (1)

D. R. Rosseinsky and R. J. Mortimer, “Electrochromic systems and the prospects for devices,” Adv. Mater. 13, 783–793 (2001).
[CrossRef]

2000 (2)

C. G. Granqvist, “Electrochromic tungsten oxide films: Review of progress 1993–1998,” Sol. Energy Mater. Sol. Cells 60, 201–262 (2000).
[CrossRef]

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

1999 (2)

P. M. S. Monk, C. Turner, and S. P. Akhtar, “Electrochemical behaviour of methyl viologen in a matrix of paper,” Electrochim. Acta 44, 4817–4826 (1999).
[CrossRef]

C. G. Granqvist, “Progress in electrochromics: Tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

1997 (1)

B. Hill, T. Roger, and F. W. Vorhagen, “Comparative analysis of quantization of color spaces on the basis of the CIELAB color-difference formula,” ACM (Assoc. Comput. Mach.) Trans. Graphics 16, 109–154 (1997).

1995 (1)

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

1989 (2)

1986 (1)

1977 (1)

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

1969 (1)

Akhtar, S. P.

P. M. S. Monk, C. Turner, and S. P. Akhtar, “Electrochemical behaviour of methyl viologen in a matrix of paper,” Electrochim. Acta 44, 4817–4826 (1999).
[CrossRef]

Argoitia, A.

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

Ashrit, P. V.

G. Beydaghyan, G. Bader, and P. V. Ashrit, “Electrochromic and morphological investigation of dry-lithiated nanostructured tungsten trioxide thin films,” Thin Solid Films 516, 1646–1650 (2008).
[CrossRef]

Avendaño, E.

C. G. Granqvist, E. Avendaño, and A. Azens, “Electrochromic coatings and devices: Survey of some recent advances,” Thin Solid Films 442, 201–211 (2003).
[CrossRef]

Azens, A.

C. G. Granqvist, E. Avendaño, and A. Azens, “Electrochromic coatings and devices: Survey of some recent advances,” Thin Solid Films 442, 201–211 (2003).
[CrossRef]

Bader, G.

G. Beydaghyan, G. Bader, and P. V. Ashrit, “Electrochromic and morphological investigation of dry-lithiated nanostructured tungsten trioxide thin films,” Thin Solid Films 516, 1646–1650 (2008).
[CrossRef]

Baloukas, B.

Baur, G.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Beydaghyan, G.

G. Beydaghyan, G. Bader, and P. V. Ashrit, “Electrochromic and morphological investigation of dry-lithiated nanostructured tungsten trioxide thin films,” Thin Solid Films 516, 1646–1650 (2008).
[CrossRef]

Brandt, G.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Çetinörgü, E.

Coombs, P. G.

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
[CrossRef]

Deb, S. K.

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

S. K. Deb, “A novel electrophotographic system,” Appl. Opt. 8, 192–195 (1969).

S. K. Deb, and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of the Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

DiNunzio, L. A.

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

Dobrowolski, J. A.

Franke, E. B.

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Granqvist, C. G.

C. G. Granqvist, E. Avendaño, and A. Azens, “Electrochromic coatings and devices: Survey of some recent advances,” Thin Solid Films 442, 201–211 (2003).
[CrossRef]

C. G. Granqvist, “Electrochromic tungsten oxide films: Review of progress 1993–1998,” Sol. Energy Mater. Sol. Cells 60, 201–262 (2000).
[CrossRef]

C. G. Granqvist, “Progress in electrochromics: Tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

C. G. Granqvist, Handbook of Inorganic Electrochromic Materials (Elsevier, 1995).

Hale, J. S.

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Hill, B.

B. Hill, T. Roger, and F. W. Vorhagen, “Comparative analysis of quantization of color spaces on the basis of the CIELAB color-difference formula,” ACM (Assoc. Comput. Mach.) Trans. Graphics 16, 109–154 (1997).

Ho, F. C.

Karuppasamy, A.

A. Subrahmanyam and A. Karuppasamy, “Optical and electrochromic properties of oxygen sputtered tungsten oxide (WO3) thin films,” Sol. Energy Mater. Sol. Cells 91, 266–274 (2007).
[CrossRef]

Klemberg-Sapieha, J. E.

Lancaster, I. M.

I. M. Lancaster and A. Mitchell, “The growth of optically variable features on banknotes,” Proc. SPIE 5310, 34–45(2004).
[CrossRef]

Larouche, S.

Leftheriotis, G.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “Dependence of the estimated diffusion coefficient of LixWO3 films on the scan rate of cyclic voltammetry experiments,” Solid State Ionics 178, 259–263 (2007).
[CrossRef]

Maloney, L. T.

Markantes, T.

P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
[CrossRef]

Martinu, L.

Mattox, D. M.

D. M. Mattox, “Particle bombardment effects on thin-film deposition: a review,” J. Vac. Sci. Technol. A 7, 1105–1114(1989).
[CrossRef]

Mitchell, A.

I. M. Lancaster and A. Mitchell, “The growth of optically variable features on banknotes,” Proc. SPIE 5310, 34–45(2004).
[CrossRef]

Monk, P. M. S.

P. M. S. Monk, C. Turner, and S. P. Akhtar, “Electrochemical behaviour of methyl viologen in a matrix of paper,” Electrochim. Acta 44, 4817–4826 (1999).
[CrossRef]

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University Press, 2007).

Mortimer, R. J.

D. R. Rosseinsky and R. J. Mortimer, “Electrochromic systems and the prospects for devices,” Adv. Mater. 13, 783–793 (2001).
[CrossRef]

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University Press, 2007).

Papaefthimiou, S.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “Dependence of the estimated diffusion coefficient of LixWO3 films on the scan rate of cyclic voltammetry experiments,” Solid State Ionics 178, 259–263 (2007).
[CrossRef]

Park, K.-W.

K.-W. Park, “Electrochromic properties of Au-WO3 nanocomposite thin-film electrode,” Electrochim. Acta 50, 4690–4693(2005).
[CrossRef]

Phillips, R. W.

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

Raksha, V. P.

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
[CrossRef]

Roger, T.

B. Hill, T. Roger, and F. W. Vorhagen, “Comparative analysis of quantization of color spaces on the basis of the CIELAB color-difference formula,” ACM (Assoc. Comput. Mach.) Trans. Graphics 16, 109–154 (1997).

Rosseinsky, D. R.

D. R. Rosseinsky and R. J. Mortimer, “Electrochromic systems and the prospects for devices,” Adv. Mater. 13, 783–793 (2001).
[CrossRef]

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University Press, 2007).

Schirmer, O. F.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Schubert, M.

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Setlakwe, L.

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

Subrahmanyam, A.

A. Subrahmanyam and A. Karuppasamy, “Optical and electrochromic properties of oxygen sputtered tungsten oxide (WO3) thin films,” Sol. Energy Mater. Sol. Cells 91, 266–274 (2007).
[CrossRef]

Trimble, C. L.

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Turner, C.

P. M. S. Monk, C. Turner, and S. P. Akhtar, “Electrochemical behaviour of methyl viologen in a matrix of paper,” Electrochim. Acta 44, 4817–4826 (1999).
[CrossRef]

van Renesse, R.

R. van Renesse, Optical Document Security, 2nd ed. (Artech House, 1998).

Vorhagen, F. W.

B. Hill, T. Roger, and F. W. Vorhagen, “Comparative analysis of quantization of color spaces on the basis of the CIELAB color-difference formula,” ACM (Assoc. Comput. Mach.) Trans. Graphics 16, 109–154 (1997).

Waldorf, A.

Wandell, B. A.

Wittwer, V.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Witzke, H.

S. K. Deb, and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of the Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

Woollam, J. A.

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Yianoulis, P.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “Dependence of the estimated diffusion coefficient of LixWO3 films on the scan rate of cyclic voltammetry experiments,” Solid State Ionics 178, 259–263 (2007).
[CrossRef]

Zabeida, O.

ACM (Assoc. Comput. Mach.) Trans. Graphics (1)

B. Hill, T. Roger, and F. W. Vorhagen, “Comparative analysis of quantization of color spaces on the basis of the CIELAB color-difference formula,” ACM (Assoc. Comput. Mach.) Trans. Graphics 16, 109–154 (1997).

Adv. Mater. (1)

D. R. Rosseinsky and R. J. Mortimer, “Electrochromic systems and the prospects for devices,” Adv. Mater. 13, 783–793 (2001).
[CrossRef]

Appl. Opt. (5)

Appl. Phys. Lett. (1)

E. B. Franke, C. L. Trimble, M. Schubert, J. A. Woollam, and J. S. Hale, “All-solid-state electrochromic reflectance device for emittance modulation in the far-infrared spectral region,” Appl. Phys. Lett. 77, 930–932 (2000).
[CrossRef]

Electrochim. Acta (3)

P. M. S. Monk, C. Turner, and S. P. Akhtar, “Electrochemical behaviour of methyl viologen in a matrix of paper,” Electrochim. Acta 44, 4817–4826 (1999).
[CrossRef]

K.-W. Park, “Electrochromic properties of Au-WO3 nanocomposite thin-film electrode,” Electrochim. Acta 50, 4690–4693(2005).
[CrossRef]

C. G. Granqvist, “Progress in electrochromics: Tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

J. Electrochem. Soc. (1)

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

J. Opt. Soc. Am. A (1)

J. Vac. Sci. Technol. A (1)

D. M. Mattox, “Particle bombardment effects on thin-film deposition: a review,” J. Vac. Sci. Technol. A 7, 1105–1114(1989).
[CrossRef]

Proc. SPIE (4)

I. M. Lancaster and A. Mitchell, “The growth of optically variable features on banknotes,” Proc. SPIE 5310, 34–45(2004).
[CrossRef]

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

P. G. Coombs, A. Argoitia, V. P. Raksha, and R. W. Phillips, “Integration of contrasting technologies into advanced optical security devices,” Proc. SPIE 5310, 299–311 (2004).
[CrossRef]

P. G. Coombs, V. P. Raksha, and T. Markantes, “Overt and covert verification via magnetic optical security devices,” Proc. SPIE 4677, 182–193 (2002).
[CrossRef]

Sol. Energy Mater. Sol. Cells (3)

C. G. Granqvist, “Electrochromic tungsten oxide films: Review of progress 1993–1998,” Sol. Energy Mater. Sol. Cells 60, 201–262 (2000).
[CrossRef]

A. Subrahmanyam and A. Karuppasamy, “Optical and electrochromic properties of oxygen sputtered tungsten oxide (WO3) thin films,” Sol. Energy Mater. Sol. Cells 91, 266–274 (2007).
[CrossRef]

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

Solid State Ionics (1)

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “Dependence of the estimated diffusion coefficient of LixWO3 films on the scan rate of cyclic voltammetry experiments,” Solid State Ionics 178, 259–263 (2007).
[CrossRef]

Thin Solid Films (2)

C. G. Granqvist, E. Avendaño, and A. Azens, “Electrochromic coatings and devices: Survey of some recent advances,” Thin Solid Films 442, 201–211 (2003).
[CrossRef]

G. Beydaghyan, G. Bader, and P. V. Ashrit, “Electrochromic and morphological investigation of dry-lithiated nanostructured tungsten trioxide thin films,” Thin Solid Films 516, 1646–1650 (2008).
[CrossRef]

Other (6)

R. van Renesse, Optical Document Security, 2nd ed. (Artech House, 1998).

Colorimetry, 3rd ed. (International Commission on Illumination (CIE), 2004).

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University Press, 2007).

C. G. Granqvist, Handbook of Inorganic Electrochromic Materials (Elsevier, 1995).

S. K. Deb, and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of the Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

The Impact of Counterfeiting on Governments and Consumers, A REPORT COMMISSIONED BY BASCAP (Business Action to Stop Counterfeiting and Piracy, 2009).

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Figures (10)

Fig. 1
Fig. 1

Conceptual example combining ISISs with an electrochromic device (ECD). ISIS A is metameric with the bleached state of the active device and is therefore invisible at normal incidence (dashed star). ISIS B is metameric with the colored state of the ECD and consequently becomes invisible during coloration. When the whole device is tilted, both ISISs change color while the rest of the device essentially remains the same. The layered structure of our ECD is also shown.

Fig. 2
Fig. 2

Dispersion curves of the as-deposited SiO 2 (solid curve) and WO 3 (dashed curve) coatings.

Fig. 3
Fig. 3

Cyclic voltammograms of the WO 3 coating at different scan rates (5, 10, 25, 50, and 100 mV / s ).

Fig. 4
Fig. 4

Transmission obtained in the darkest colored state for the 50 mV / s cyclic voltammetry measurement and corresponding coloration efficiency (dashed curve).

Fig. 5
Fig. 5

Variation of the transmission spectrum of the EC device for an applied voltage of 3 V for up to 30 s.

Fig. 6
Fig. 6

Luminance variation in transmission for five coloration and bleaching cycles of the EC device. Higher luminance values correspond to a higher transmission.

Fig. 7
Fig. 7

Transmission spectra of the targets (solid curve: WO 3 20 s coloration state), the designed filter (dashed curve), and the deposited filter (dotted curve). Also included are the Δ E ab * values under different illuminants between the target and the design, the design and the deposited filter, and the deposited filter and the target.

Fig. 8
Fig. 8

Color variation of the EC device during coloration (circles) and of the metameric interference filter as a function of the observation angle (triangles). The square represents the reference white. The upper inset shows the luminance (Y) variation with time of the EC device. Calculations are done under illuminant D65 in the x y Y color space.

Fig. 9
Fig. 9

Theoretical color difference under illuminant D65 between the EC device and the designed filter for four angles of observation ( 0 ° to 30 ° ). The gray area indicates the color matching zone ( Δ E ab , D65 * 4 ). The curve with the black dots is the color difference obtained for the deposited filter at normal incidence.

Fig. 10
Fig. 10

Comparison of the transmission spectra of various design strategies of a metameric filter. A specific 13 layer quarter-wave stack was used as a starting point for the refining process. Optimization targets are indicated in the figure: (a) color targets only, (b) color and transmission targets with equal tolerances, (c) color and transmission targets with tolerances that are inversely proportional to the luminous efficiency curve of the human eye [gray area in (a)].

Tables (3)

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Table 1 Deposition Parameters and Thicknesses of the Individual EC Device Layers

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Table 2 Design of the Metameric Filter

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Table 3 Color Difference for Filters Designed Using Different Types of Targets and Methods

Equations (4)

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WO 3 + x M + + x e M x WO 3 ,
Δ E ab,I * = [ ( L 2 * L 1 * ) 2 + ( a 2 * a 1 * ) 2 + ( b 2 * b 1 * ) 2 ] 1 / 2 ,
i p = 0.4463 n F A c n F v D R T ,
CE = ln [ T b / T c ] [ Q / A ] ,

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