Abstract

Ultrabright light emitting diodes (LEDs) are a new light source for visual psychophysics and microscopy. The new LEDs are intended primarily for room and exterior illumination, and the manufacturers’ specifications are adequate for that. However, we use them as light sources in situations where a more complete characterization may be useful. For one set of LEDs we have measured the radiometric intensity and its distribution in space and wavelength, and we have tested for interactions of these variables and their dependence on driver configuration. We describe techniques for making these measurements and give a link to a simple calculator for converting among radiometric and photometric measures, as well as an evaluation of the safety considerations these very bright sources demand.

© 2005 Optical Society of America

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References

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  1. M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
    [CrossRef]
  2. S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
    [CrossRef]
  3. A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
    [CrossRef]
  4. Lumileds Lighting, “Power Light Source, Luxeon V Star,” Technical Data DS30,(2003), www.lumileds.com .
  5. R. H. Webb, http//www.eri.harvard.edu/faculty/webb/LightCalc.exe . and http//www.eri.harvard.edu/faculty/webb/Light-Calculator-instructions.doc .
  6. United Detector Technology, Santa Monica, Calif., Model 40X.
  7. webb@eri.harvard.edu.
  8. http://www.oceanoptics.com .
  9. Fourward Technologies, Buena Vista, Va., http://www.fourward.com .
  10. F. Delori, Schepens Eye Research Institute, 20 Staniford Street, Boston, Massachusetts (personal communication, 2005).

2001 (2)

M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
[CrossRef]

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

1994 (1)

S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
[CrossRef]

Bergh, A.

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

Craford, G

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

Craford, M. G.

M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
[CrossRef]

Delori, F.

F. Delori, Schepens Eye Research Institute, 20 Staniford Street, Boston, Massachusetts (personal communication, 2005).

Duggal, A.

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

Haiz, R.

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

Holonyak, N.

M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
[CrossRef]

Kish, F. A.

M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
[CrossRef]

Mukai, T.

S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
[CrossRef]

Nakamura, S.

S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
[CrossRef]

Senoh, M.

S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
[CrossRef]

Appl. Phys. Lett. (1)

S. Nakamura, T. Mukai, M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64, 1687–1689 (1994).
[CrossRef]

Phys. Today (1)

A. Bergh, G Craford, A. Duggal, R. Haiz, “The promise and challenges of solid-state lightning,” Phys. Today 54(12), 42 (2001), http://www.physicstoday.org .
[CrossRef]

Sci. Am. (1)

M. G. Craford, N. Holonyak, F. A. Kish, “In pursuit of the ultimate lamp,” Sci. Am. 284(2) 63–67 (2001).
[CrossRef]

Other (7)

Lumileds Lighting, “Power Light Source, Luxeon V Star,” Technical Data DS30,(2003), www.lumileds.com .

R. H. Webb, http//www.eri.harvard.edu/faculty/webb/LightCalc.exe . and http//www.eri.harvard.edu/faculty/webb/Light-Calculator-instructions.doc .

United Detector Technology, Santa Monica, Calif., Model 40X.

webb@eri.harvard.edu.

http://www.oceanoptics.com .

Fourward Technologies, Buena Vista, Va., http://www.fourward.com .

F. Delori, Schepens Eye Research Institute, 20 Staniford Street, Boston, Massachusetts (personal communication, 2005).

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Figures (6)

Fig. 1
Fig. 1

Typical radiation patterns from a series of 5 W “Blue” LEDs. The curves labeled *, △, and ♢ describe single LEDs from one batch. These variations probably come from the positioning of the integral lens. The other two curves, labeled ○ and ×, are from different batches.

Fig. 2
Fig. 2

Layout for measuring the LED radiation pattern. The LED is rotated about an axis through its emissive surface, and the emitted power is measured through a 2 mm aperture at 61 mm from that axis.

Fig. 3
Fig. 3

The AlInGaP LEDs are quite narrow and single peaked, while the InGaN group’s wider bandwidths seem to be the result of multiple peaks.

Fig. 4
Fig. 4

A 5 W “Blue” LED shows variation in both peak wavelength and shape as a function of viewing angle.

Fig. 5
Fig. 5

The LED line shape is far from Gaussian, with extra power in the long wavelength tails. This is particularly problematic for excitation of fluorescence, where we have had to include an interference filter for the excitation light.

Fig. 6
Fig. 6

Snapshot of the calculator we use to translate within and between radiometric and photometric units.

Tables (2)

Tables Icon

Table 1 Specification Sheet

Tables Icon

Table 2 Measured Powers

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