Abstract

We fabricated an emergency illumination panel by stacking two translucent pictures, one of which was painted with ink and the other with phosphors. When the panel was illuminated by backlight or room light, only the ink-printed picture was visible to the human eye and only the phosphorescent picture was visible in darkness. A two-way mirror was inserted between the two pictures both to prevent superimposition of the two images and to enhance phosphorescence. This phosphorescent emergency sign acted as an illuminator independently of electric power sources and provided sufficient brightness for reading newspaper headlines.

© 2004 Optical Society of America

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References

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  1. T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
    [CrossRef]
  2. M. Saito, K. Yamamoto, “Bright afterglow illuminator made of phosphorescent material and fluorescent fibers,” Appl. Opt. 39, 4366–4371 (2000).
    [CrossRef]
  3. J. M. Rice, “New design includes everyone in synagogue worship,” Opt. Photon. News 9(7), 9 (1998).
  4. Data from Nemoto Co., Ltd. product catalog (Nemoto, Tokyo, 2001).
  5. This picture was downloaded from http://www03.u-page.so-net.ne.jp/zb3/utiyama/ .
  6. J. Hecht, Optics (Scribner’s, New York, 1987), p. 39.

2000

1998

J. M. Rice, “New design includes everyone in synagogue worship,” Opt. Photon. News 9(7), 9 (1998).

1996

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Aoki, Y.

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Hecht, J.

J. Hecht, Optics (Scribner’s, New York, 1987), p. 39.

Matsuzawa, T.

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Murayama, Y.

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Rice, J. M.

J. M. Rice, “New design includes everyone in synagogue worship,” Opt. Photon. News 9(7), 9 (1998).

Saito, M.

Takeuchi, N.

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Yamamoto, K.

Appl. Opt.

J. Electrochem. Soc.

T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+, Dy3+,” J. Electrochem. Soc. 143, 2670–2673 (1996).
[CrossRef]

Opt. Photon. News

J. M. Rice, “New design includes everyone in synagogue worship,” Opt. Photon. News 9(7), 9 (1998).

Other

Data from Nemoto Co., Ltd. product catalog (Nemoto, Tokyo, 2001).

This picture was downloaded from http://www03.u-page.so-net.ne.jp/zb3/utiyama/ .

J. Hecht, Optics (Scribner’s, New York, 1987), p. 39.

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Figures (7)

Fig. 1
Fig. 1

Structures of emergency illumination panels. (a), (b) A translucent picture is stacked on a phosphorescent sign. (c), (d) A phosphorescent sign is stacked on a painted picture. (e), (f) A two-way mirror is sandwiched between an upper phosphorescent sign and a lower picture. In (a), (c), and (e), room light I R illuminates the panel from above. Backlight I B also illuminates the panel in (e). (b), (d), (f) A dark situation without illumination. I P and I S denote light from the picture and from the phosphorescent sign, respectively.

Fig. 2
Fig. 2

(a) Absorption and emission spectra of blue and green phosphors. These data were taken from a phosphor catalog.4 (b) Temporary change in phosphorescence intensity. The sample was a polysiloxane disk of ∼10-mm thickness and ∼90-mm diameter in which green phosphor particles were dispersed at ∼10 vol. %. Phosphorescence intensity was measured with a photodiode that was placed 35 mm from the sample surface. A mercury lamp was used for phosphor excitation. The horizontal axis shows time from start (○) or stop (●) of excitation. Blue phosphor exhibited virtually the same characteristics.

Fig. 3
Fig. 3

Emergency sign painted with phosphor-dispersed epoxy resin. (a) This photograph was taken in darkness after the phosphor had been excited by a fluorescent lamp for 5 min. The lighter portions of the photograph emitted blue phosphorescence, and the other portions emitted green phosphorescence, corresponding to phosphor types. (b) This photograph was taken in a bright room. The illuminance of the room light was 300 lx at the panel surface. The entire sign appeared uniform regardless of phosphor type; i.e., the emergency sign was not visible.

Fig. 4
Fig. 4

Transmission (T) spectra of 27 colors that were printed upon a polyester sheet by an ink-jet printer.

Fig. 5
Fig. 5

(a) Fluorescence spectrum of a backlight lamp. (b) Transmission (T) and reflection (R) spectra of a two-way mirror.

Fig. 6
Fig. 6

(a) Test pattern that was printed with the 27 colors analyzed in Fig. 4. (b) Superimposed images of the test pattern and the phosphorescent emergency sign. This photograph was taken in darkness after the panel had been illuminated by backlight for 5 min.

Fig. 7
Fig. 7

Photographs of the panel taken with and without illumination. (a), (b) Image of a toy fish5 changed to an emergency sign when backlight and room light were turned off. The photograph in (a) was taken after the panel had been illuminated for 5 min. The photograph in (b) was taken 10 s after the illumination had been turned off. (c), (d) An image of a university building changed to an emergency sign when backlight and room light were turned off. The photograph in (c) was taken after the panel had been illuminated for 5 min. The photograph in (d) was taken 60 s after illumination had been turned off.

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