Abstract

A LCD backlighting device that uses a diffractive light extractor has been developed for applications in which pointlike light sources are employed. The novel system eliminates the images of light sources, which appear as bright lines emanating from each source in the conventional diffractive approach. In addition, the system illuminates the LCD uniformly: Modulation of the diffractive structure as a function of position is used to control the output field of this extended planar light source.

© 2001 Optical Society of America

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References

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  1. Semiconductor Industry Association, The National Technology Roadmap for Semiconductors, 1997 ed. (Semiconductor Industry Association, San Jose, California). For recent information, see http://public.itrs.net .
  2. See product information on batteries, for example at http://www.nokia.com .
  3. D. J. Schertler, N. George, “Uniform scattering patterns from grating-diffuser cascades for display applications,” Appl. Opt. 38, 291–303 (1999).
    [CrossRef]
  4. B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
    [CrossRef]
  5. J. Turunen, F. Wyrowski, eds., Diffractive Optics for Industrial and Commercial Applications (Wiley, Berlin, 1997).
  6. J. M. Teijido, H. P. Herzig, R. Dändliger, “Design of a non-conventional illumination system using a scattering light pipe,” in Design and Engineering of Optical Systems, J. J. Braat, ed., Proc. SPIE2774, 747–756 (1996).
    [CrossRef]
  7. A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
    [CrossRef]
  8. J. M. Teijido, H. P. Herzig, R. Dändliger, “Illumination light pipe using micro-optics as diffuser,” in Holographic and Diffractive Techniques, G. J. Dansmann, ed., Proc. SPIE2951, 146–155 (1996).
    [CrossRef]
  9. C.-Y. Tai, “A small-area backlight employing divergent-angle beam rotator and unique double-layer micro-prisms,” SID Symp. 29, 556–559 (1998).
    [CrossRef]
  10. S.-I. Ochiai, “Light guide plates and light guide plate assembly utilizing diffraction grating,” U.S. patent5,703,667 (30December1997).
  11. J. Turunen, “Diffraction theory of microrelief gratings,” in Micro-Optics: Elements, Systems and Applications, H. P. Herzig, ed. (Taylor & Francis, London, 1997), chap. 2.
  12. T. Tamir, ed., Integrated Optics, 2nd ed. (Springer-Verlag, Berlin, 1979).
  13. S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
    [CrossRef]
  14. T. Tamir, S. T. Peng, “Analysis and design of grating couplers,” Appl. Opt. 14, 235–254 (1977).

1999

B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
[CrossRef]

D. J. Schertler, N. George, “Uniform scattering patterns from grating-diffuser cascades for display applications,” Appl. Opt. 38, 291–303 (1999).
[CrossRef]

1998

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

C.-Y. Tai, “A small-area backlight employing divergent-angle beam rotator and unique double-layer micro-prisms,” SID Symp. 29, 556–559 (1998).
[CrossRef]

1977

T. Tamir, S. T. Peng, “Analysis and design of grating couplers,” Appl. Opt. 14, 235–254 (1977).

1975

S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
[CrossRef]

Baba, M.

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

Bertoni, H. L.

S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
[CrossRef]

Cormack, I. G.

B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
[CrossRef]

Dändliger, R.

J. M. Teijido, H. P. Herzig, R. Dändliger, “Illumination light pipe using micro-optics as diffuser,” in Holographic and Diffractive Techniques, G. J. Dansmann, ed., Proc. SPIE2951, 146–155 (1996).
[CrossRef]

J. M. Teijido, H. P. Herzig, R. Dändliger, “Design of a non-conventional illumination system using a scattering light pipe,” in Design and Engineering of Optical Systems, J. J. Braat, ed., Proc. SPIE2774, 747–756 (1996).
[CrossRef]

George, N.

Herzig, H. P.

J. M. Teijido, H. P. Herzig, R. Dändliger, “Design of a non-conventional illumination system using a scattering light pipe,” in Design and Engineering of Optical Systems, J. J. Braat, ed., Proc. SPIE2774, 747–756 (1996).
[CrossRef]

J. M. Teijido, H. P. Herzig, R. Dändliger, “Illumination light pipe using micro-optics as diffuser,” in Holographic and Diffractive Techniques, G. J. Dansmann, ed., Proc. SPIE2951, 146–155 (1996).
[CrossRef]

Horibe, A.

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

Koike, Y.

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

Layet, B.

B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
[CrossRef]

Nihei, E.

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

Ochiai, S.-I.

S.-I. Ochiai, “Light guide plates and light guide plate assembly utilizing diffraction grating,” U.S. patent5,703,667 (30December1997).

Peng, S. T.

T. Tamir, S. T. Peng, “Analysis and design of grating couplers,” Appl. Opt. 14, 235–254 (1977).

S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
[CrossRef]

Schertler, D. J.

Taghizadeh, M. R.

B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
[CrossRef]

Tai, C.-Y.

C.-Y. Tai, “A small-area backlight employing divergent-angle beam rotator and unique double-layer micro-prisms,” SID Symp. 29, 556–559 (1998).
[CrossRef]

Tamir, T.

T. Tamir, S. T. Peng, “Analysis and design of grating couplers,” Appl. Opt. 14, 235–254 (1977).

S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
[CrossRef]

Teijido, J. M.

J. M. Teijido, H. P. Herzig, R. Dändliger, “Illumination light pipe using micro-optics as diffuser,” in Holographic and Diffractive Techniques, G. J. Dansmann, ed., Proc. SPIE2951, 146–155 (1996).
[CrossRef]

J. M. Teijido, H. P. Herzig, R. Dändliger, “Design of a non-conventional illumination system using a scattering light pipe,” in Design and Engineering of Optical Systems, J. J. Braat, ed., Proc. SPIE2774, 747–756 (1996).
[CrossRef]

Turunen, J.

J. Turunen, “Diffraction theory of microrelief gratings,” in Micro-Optics: Elements, Systems and Applications, H. P. Herzig, ed. (Taylor & Francis, London, 1997), chap. 2.

App. Opt.

B. Layet, I. G. Cormack, M. R. Taghizadeh, “Stripe color separation with diffractive optics,” App. Opt. 38, 7193–7201 (1999).
[CrossRef]

Appl. Opt.

IEEE Trans. Microwave Theory Tech.

S. T. Peng, T. Tamir, H. L. Bertoni, “Theory of periodic dielectric waveguides,” IEEE Trans. Microwave Theory Tech. MTT-23, 123–133 (1975).
[CrossRef]

SID Symp.

A. Horibe, M. Baba, E. Nihei, Y. Koike, “High-efficiency and high-visual-quality LCD backlighting system,” SID Symp. 29, 153–156 (1998).
[CrossRef]

C.-Y. Tai, “A small-area backlight employing divergent-angle beam rotator and unique double-layer micro-prisms,” SID Symp. 29, 556–559 (1998).
[CrossRef]

Other

S.-I. Ochiai, “Light guide plates and light guide plate assembly utilizing diffraction grating,” U.S. patent5,703,667 (30December1997).

J. Turunen, “Diffraction theory of microrelief gratings,” in Micro-Optics: Elements, Systems and Applications, H. P. Herzig, ed. (Taylor & Francis, London, 1997), chap. 2.

T. Tamir, ed., Integrated Optics, 2nd ed. (Springer-Verlag, Berlin, 1979).

J. M. Teijido, H. P. Herzig, R. Dändliger, “Illumination light pipe using micro-optics as diffuser,” in Holographic and Diffractive Techniques, G. J. Dansmann, ed., Proc. SPIE2951, 146–155 (1996).
[CrossRef]

J. Turunen, F. Wyrowski, eds., Diffractive Optics for Industrial and Commercial Applications (Wiley, Berlin, 1997).

J. M. Teijido, H. P. Herzig, R. Dändliger, “Design of a non-conventional illumination system using a scattering light pipe,” in Design and Engineering of Optical Systems, J. J. Braat, ed., Proc. SPIE2774, 747–756 (1996).
[CrossRef]

Semiconductor Industry Association, The National Technology Roadmap for Semiconductors, 1997 ed. (Semiconductor Industry Association, San Jose, California). For recent information, see http://public.itrs.net .

See product information on batteries, for example at http://www.nokia.com .

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Figures (13)

Fig. 1
Fig. 1

Backlighting geometry with discrete, essentially pointlike sources.

Fig. 2
Fig. 2

Backlighting setup with a diffractive light extractor.

Fig. 3
Fig. 3

Side view of the grating outcoupler and the propagation directions of various diffraction orders.

Fig. 4
Fig. 4

Total outcoupling efficiencies as functions of fill factor f: (a) reflected and (b) transmitted orders. Solid curves, θin = 60°; dashed curves, θin = 70°; dotted curves, θin = 80°.

Fig. 5
Fig. 5

Formation of the LED image pattern. The images are seen by the eye at a distance proportional to the path length traveled by the ray. The phenomenon is the same whether the diffractive structure is on the bottom or on the top surface of the light guide. However, which geometry produces stronger lines depends on the structure’s transmission and reflection properties.

Fig. 6
Fig. 6

CCD picture of the light output from the light guide operated with three LEDs with the conventional diffractive structure.

Fig. 7
Fig. 7

Top view of the directions of diffraction orders for conical incidence.

Fig. 8
Fig. 8

Placement of outcoupling, nonconical (orientation A) and of deflecting, conical (orientation B) gratings.

Fig. 9
Fig. 9

Structure of a pixellated grating. Dimension w is the width of one working field of the Leica LION LV-1 e-beam machine.

Fig. 10
Fig. 10

Designed proportion of type A gratings (nonconical) for an element consisting of 180 × 410 working fields. The LEDs are in positions (50, 0) and (130, 0).

Fig. 11
Fig. 11

Atomic-force microscopy picture of the hot embossed structure.

Fig. 12
Fig. 12

CCD picture of the light output from a 1-mm-thick pixellated light guide replicated in plastic. The dimensions of the element are 18 mm × 41 mm.

Fig. 13
Fig. 13

CCD picture of the light output from a 1-mm-thick pixellated light guide replicated in plastic. The dimensions of the element are 10 mm × 100 mm.

Tables (2)

Tables Icon

Table 1 Diffraction Efficiencies of Reflected (ηr) and Transmitted (ηt) Orders m with Their Propagation Directions θr,m and θ t,m a

Tables Icon

Table 2 Diffraction Efficiencies of Orders ±m and Deflection Angles φ m for Several Incidence Angles θ in a

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

n3 sin θm=n1 sin θin+mλ/d,
Emz=Em0exp-2αmz,
sj=-log2-exp2αmsj-1,

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