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Patent 2413700 Summary

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(12) Patent: (11) CA 2413700
(54) English Title: BACKLIGHT WITH STRUCTURED SUFACES
(54) French Title: RETROECLAIRAGE A SURFACES STRUCTUREES
Status: Deemed expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • G02B 6/10 (2006.01)
  • F21V 8/00 (2006.01)
  • G02B 27/00 (2006.01)
  • G02F 1/13357 (2006.01)
(72) Inventors :
  • GARDINER, MARK E. (United States of America)
  • COBB, SANDFORD (United States of America)
  • KRETMAN, WADE D. (United States of America)
(73) Owners :
  • 3M INNOVATIVE PROPERTIES COMPANY (United States of America)
(71) Applicants :
  • 3M INNOVATIVE PROPERTIES COMPANY (United States of America)
(74) Agent: OYEN WIGGS GREEN & MUTALA LLP
(74) Associate agent:
(45) Issued: 2007-01-09
(86) PCT Filing Date: 2001-07-05
(87) Open to Public Inspection: 2002-01-17
Examination requested: 2002-12-18
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/US2001/021294
(87) International Publication Number: WO2002/004858
(85) National Entry: 2002-12-18

(30) Application Priority Data:
Application No. Country/Territory Date
09/613,313 United States of America 2000-07-11

Abstracts

English Abstract




A backlight includes a lightguide (16), a light source (12) disposed with
respect to the lightguide (16) to introduce light into the lightguide (16) and
a turning film. Optical structures (40) are formed in one of an output surface
(18) and a back surface (20) of the lightguide (16). The optical structures
(40) are arranged to extract light from the lightguide (16). A back reflector
(24) is disposed adjacent the back surface (20). The optical structures (40)
are formed to include a varying pattern arranged to mask non-uniformities in
the output of the lightguide (16).


French Abstract

L'invention concerne un rétroéclairage comportant un guide de lumière, une source lumineuse placée par rapport au guide de lumière de façon à y introduire la lumière et un film tournant. Des structures optiques sont formées dans l'une des surfaces de sortie et une surface dorsale du guide de lumière. Les structures optiques sont disposées de façon à extraire la lumière du guide de lumière. Un réflecteur de fond jouxte la surface arrière. Les structures optiques sont formées de façon à comprendre un motif variable conçu pour masquer des non-uniformités dans la sortie du guide de lumière.

Claims

Note: Claims are shown in the official language in which they were submitted.





WHAT IS CLAIMED IS:
1. A backlight comprising:
a lightguide;
a light source disposed with respect to the lightguide to
introduce light into the lightguide;
optical structures formed in one of an output surface and a
back surface of the lightguide, the optical structures arranged to
extract light from the lightguide;
a turning film disposed adjacent to the output surface;
a back reflector disposed adjacent the back surface; and
wherein the optical structures include a varying characteris-
tic arranged to mask non-uniformities in the output of the
lightguide.
2. The backlight of claim 1, wherein the optical structures comprise
grooves.
3. The backlight of claim 2, wherein the grooves are arranged
substantially parallel to the light source.
4. The backlight of claim 2, wherein the grooves are arranged
substantially perpendicular to the light source.
5. The backlight of Claim 2, wherein the grooves are arranged at an
angle between about 0 degrees to about 90 degrees to the light
source.
6. The backlight of claim 2, wherein the grooves have a shape
selected from the group of shapes consisting of "V" grooves, flat
grooves and arcs.



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7. The backlight of claim 1, wherein the back reflector is directly
secured to the back surface.
8. The backlight of claim 1, wherein the back reflector is adhesively
bonded to the back surface.
9. The backlight of claim 1, wherein the back reflector is secured to
the back surface by a dot adhesive pattern.
10. The backlight of claim 1, wherein the back reflector is formed to
include optical structures, the optical structures arranged to
enhance the reflection of light back through the lightguide.
11. The backlight of claim 1, wherein the lightguide is one of a
wedge lightguide, a slab lightguide and a pseudo-wedge
lightguide.
12. The backlight of claim 1, wherein the optical structures are
formed in an optical film, and the optical film is laminated to the
lightguide.
13. The backlight of claim 1, wherein the lightguide is formed with
optical structures in each of the output surface and the back
surface.
14. The backlight of claim 1, wherein the varying characteristic
varies as a function of a position on the one of the output surface
and the back surface.



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15. The backlight of claim 1, wherein the varying characteristic
linearly decreases in magnitude from a first edge of the lightguide
to a second edge of the lightguide.
16. An optical film comprising:
a light transmissive film having a first surface and a second
surface; and
optical structures formed in the first surface, the optical
structures including a varying characteristic arranged to mask
nonuniformities in an output of the optical film, the varying
characteristic varying as a function of a position of the varying
characteristic on the first surface.
17. The optical film of claim 16, wherein the optical structures com-
prise grooves.
18. The optical film of claim 16, wherein the grooves are arranged to
be substantially parallel to an edge of the optical film.
19. The optical film of claim 16, wherein the grooves are arranged at
an angle between about 0 degrees to about 90 degrees to an edge
of the optical film.
20. The optical film of claim 16, wherein the second surface of the
film is adapted to be secured to one of a back surface and an
output surface of a second optical film.
21. The optical film of claim 16, wherein the grooves have a shape
selected from the group of shapes consisting of "V" grooves, flat
grooves and arcs.



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22. The optical film of claim 16, wherein the varying characteristic
linear decreases in magnitude from a first edge of the optical film
to a second edge of the optical film.
23. A lens comprising:
a first surface and a second surface, and
optical structures formed in one of the first surface and the
second surface, the optical structures including a varying charac-
teristic arranged to mask non-uniformities in an output of the lens,
the characteristic varying as function of a position of the optical
structure on said surface.
24. The lens of claim 23, the lens having a Fresnel lens structures,
and the optical structures being formed in the Fresnel lens struc-
tures.
25. The lens of claim 23, wherein the lens comprises one of a linear
lens structure and a circular lens structure.
26. A lightguide comprising:
an input surface, a back surface and an output surface; and
optical structures formed in one of the input surface, the
back surface and the output surface, the optical structures includ-
ing a varying characteristic arranged to mask non-uniformities in
an output of the lightguide, the characteristic varying as a function
of a position of the optical structures on the input, back and
output surfaces respectively.
27. The lightguide of claim 26, wherein the optical structures are
formed in a film and wherein the film is secured to the input,
back and output surfaces respectively.


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28. The lightguide of claim 27, wherein the film is secured to said
surface by bonding.
29. The lightguide of claim 26, wherein the optical structures com-
prise one of "V" grooves, flat grooves and arcs.
30. The lightguide of claim 26, wherein the optical structures com-
prise grooves arranged perpendicular to the input edge.
31. The lightguide of claim 26, wherein the optical structures com-
prise grooves arranged at an angle between 0 degrees to 90 de-
grees to the input surface.
32. The lightguide of claims 26, wherein the optical structures com-
prise discrete optical structures dispersed in a pattern.
33. The lightguide of claim 26, wherein the optical structures are
formed in each of the back surface and the output surface.
34. The lightguide of claim 26, wherein the back surface is formed
with facets and the optical structures are formed in the output
surface.
35. The lightguide of claim 26, wherein the varying characteristic
varies as a function of a position of the varying characteristic on
said surface.

Description

Note: Descriptions are shown in the official language in which they were submitted.




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BACKLIGHT WITH STRUCTURED SURFACES
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates generally to a backlight and more
particularly to backlights including lightguides formed with optical
structures in one or more surfaces of the lightguide.
Description of the Related Technology
Backlit display devices, such as liquid crystal display
(LCD) devices, commonly use a wedge-shaped lightguide. The wedge-shaped
lightguide couples light from a substantially linear source, such as a
cold cathode fluorescent lamp (CCFL), to a substantially planar output.
The planar output is then used to illuminate the LCD.
One measure of the performance of the backlit display is its
uniformity. A user can easily perceive relatively small differences in
brightness of a display from one area of the display to the next. Even
relatively small non-uniformities can be very annoying to a user of the
display.
Surface diffusers or bulk diffuser sheets, which scatter the
2 0 light exiting the lightguide, are sometimes used to mask or soften non-
uniformities. However, this diffusion also results in light being
directed away from a preferred viewing axis. A net result can be a
reduction in overall brightness of the display along the preferred
viewing axis, which is another performance measure of a display device.
2 5 From a subjective standpoint relatively small increases or
decreases in overall brightness are not as easily perceived by the user
of the display device as are discrete nonuniformities. However, the
display device designer is discouraged by even the smallest decreases in



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overall brightness including decreases so small they might only be
perceived by objective measurement. This is because display brightness
and power requirements of the display are closely related. If overall
brightness can be increased without increasing the required power, the
designer can actually allocate less power to the display device, yet
still achieve an acceptable level of brightness. For battery powered
portable devices, this translates to longer running times.
SUN~1ARY OF THE INVENTTON
In accordance with the invention, an optical element, such
as a lightguide, optical film or lens, is formed with a predetermined,
programmed pattern of optical structures. The optical structures may be
arranged to selectively correct fox non-uniformities in the output of
the optical element, or may be arranged to otherwise effect the
performance of the display in a predetermined, and designed manner.
In a first aspect of the invention, an optically
transmissive film having a first surface and a second surface and a
first edge and a second edge is formed with a plurality of optical
structures formed in the first surface. The plurality of optical
structures are arranged on the first surface in a predetermined pattern,
2 0 and each optical structure has at least one characteristic selected from
the group consisting of an amplitude, a period and an aspect ratio.
Each characteristic has a first value for a first predetermined location
on the film between the first edge and the second edge and the
characteristic has a second value, different from the first value, for a
2 5 second predetermined location on the film, different than the first
predetermined location on the film, between the first edge and the
second edge.



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In another aspect of the invention, the structure in
accordance with the invention is part of a thick optical element, such
as for example, a lightguide wedge or slab. The structure is achieved
on the thick element through injection molding, casting, compression
molding, or by bonding a film with the structure to the thick optical
element.
BRIEF DESCRIPTION OF THE DRAWINGS
The many advantages and features of the present invention
1 0 will become apparent to one of ordinary skill in the art from the
following detailed description of several preferred embodiments of the
invention with reference to the attached drawings wherein like reference
numerals refer to like elements throughout and in which:
FIG. 1 is a perspective view of an illumination device
adapted in accordance with an embodiment of the invention;
FIG. 2 is a perspective view of an optical film
incorporating a programmed pattern of optical structures in accordance
with one embodiment of the invention;
FIG. 3 is a perspective view of an optical film
2 0 incorporating a programmed pattern of optical structures in accordance
with another embodiment of the invention;
FIG. 4 is a perspective view of an optical film
incorporating a programmed pattern of optical structures in accordance
with another embodiment of the invention;
2 5 FIG. 5 is a perspective view of a lightguide wedge
incorporating a programmed pattern of optical structures in accordance
with another embodiment of the invention;



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FIG. 6 is a perspective view of a lightguide wedge
incorporating an in-phase programmed pattern of optical structures in
accordance with another embodiment of the invention;
FIG. 7 is a cross-section view taken along line 7-7 of FIG.
6;
FIG. 8 is a perspective view of a lightguide wedge
incorporating an out-of-phase programmed pattern of optical structures
in accordance with another embodiment of the invention;
FIG. 9 is perspective view of a linear lens structure
incorporating a programmed pattern of optical structures in accordance
with another embodiment of the invention;
FIG. 10 is a schematic plan view representation of a
circular lens structure incorporating a programmed pattern of optical
structures in accordance with another embodiment of the invention;
FIG. 11 is a schematic perspective view representation of
the circular lens structure shown in FIG. 10;
FIG. 12 is a perspective view of an optical film
incorporating a programmed pattern of optioal structures in accordance
with an alternate preferred embodiment of the invention;
2 0 FIG. 13 is a perspective view of an optical film
incorporating a programmed pattern of optical structures in accordance
with an alternate preferred embodiment of the invention.;
FIG. 14 is a perspective view of an optical film
incorporating a programmed pattern of optical structures in accordance
2 5 with an alternate preferred embodiment of the invention;
FIG. 15 is a perspective view of a lightguide incorporating
a first programmed pattern of optical structures in a top surface and a



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second programmed pattern of optical structures in a bottom surface in
accordance with a preferred embodiment of the invention;
FIG. 16 is a side view illustration of the lightguide shown
in FIG. 15;
FIG. 17 is an exploded perspective view of a backlight in
accordance with a preferred embodiment of the invention;
FIG. 18 is an exploded perspective view of a backlight in
accordance with a preferred embodiment of the invention;
FIG. 19 is a plot illustrating light output distribution for
the backlight illustrated in FIG. 17;
FIG. 20 is a plot illustrating light output distribution for
the backlight illustrated in FIG. 18;
FIG. 21 is a side view illustration of a backlight in
accordance with the prior art;
FIG. 22 is a side view illustration of a backlight in
accordance with a preferred embodiment of the invention;
FIGS. 23-28 are side view illustrations of various
configurations of backlights in accordance with the preferred
embodiments of the invention.



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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is described in terms of several
preferred embodiments, and particularly, in terms of an optical film or
a lightguide suitable for use in a backlighting system typically used in
flat panel display devices, such as a laptop computer display or a
desktop flat panel display. The invention, however, is not so limited
in application and one of ordinary skill in the art will appreciate that
it has application to virtually any optical system, for example, to
projection screen devices and flat panel televisions. It will be
further appreciated that the invention has application to small LCD
display devices such as those found in cellular telephones, personal
digital assistants (PDAs), pagers, and the like. Therefore, the
embodiments described herein should not be taken as limiting of the
broad scope of the invention.
Referring to Fig. l, an illumination system 10 includes a
light source 12; a light source reflector 14; a lightguide 16 with an
output surface 18, a back surface 20, an input surface 21 and an end
surface 22; a reflector 24 adjacent the back surface 20; a first light
redirecting element 26; a second light redirecting element 28; and a
2 0 reflective polarizer 30. The 1'ightguide 16 may be a wedge, a
modification thereof or a slab. As is well known, the purpose of the
lightguide is to provide for the distribution of light from the light
source 12 over an area much larger than the light source 12, and more
particularly, substantially over the entire area formed by the output
surface 18. The lightguide 16 further preferably accomplishes these
tasks in a compact, thin package.
The light source 12 may be a CCFL that inputs light to the



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edge surface 21 of the lightguide 16, and the lamp reflector 14 may be a
reflective film that wraps around the light source 12 forming a lamp
cavity. The back reflector 24 is located behind the lightguide 16
adjacent to the back surface 20. The back reflector 24 may be an
efficient back reflector, e.g., a diffuse reflective film or a specular
reflective film.
In the embodiment shown, the edge-coupled light propagates
from the input surface 2l toward the end surface 22, confined by total
internal reflection (TIR). The light is extracted from the lightguide
16 by frustration of the TIR. A ray confined within the lightguide 16
increases its angle of incidence relative to the plane of the top and
bottom walls, due to the wedge angle, with each TIR bounce. Thus, the
light eventually refracts out of the output surface 18 and at a glancing
angle thereto, because it is no longer contained by TIR. Some of the
light rays are extracted out of the back surface 20. These light rays
are reflected back into and through the lightguide 16 by the back
reflector 24. First light redirecting element 26 is arranged as a
turning film to redirect these light rays exiting the output surface 18
along a direction substantially parallel to a preferred viewing
direction.
With reference still to FIG. 1 and with brief reference also
to FIG. 2, the first light redirecting element 26 may be a light
transmissive optical film with a first surface 32 and a second surface
34. The first surface 32, in a turning film application, is arranged as
an input surface and is formed with prisms 44, which refract and reflect
the light exiting the lightguide 16 along the preferred viewing
direction. The second surface 34 is therefore an output surface. The

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prisms may have a substantially uniform configuration, or may have a
non-uniform configuration as described in commonly assigned
International Patent Publication WO 01/27663 published
19 April 2001.
Referring back to FIG. 1, the second light redirecting
element 28 may not be required in every configuration of the
illumination system 10. When included in the system 10, the second
light redirecting element may be a diffuser, a lenticular spreader or a
prism film, for example a brightness enhancing film such as the 3M
Brightness Enhancement film product (sold as BEFII or BEFIII) available
from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota.
The reflective polarizes 30 may be an inorganic, polymeric or
choleateric liquid crystal polarizes film. A suitable film is the
Diffuse Reflective Polarizes film product (sold as DRPF) or the Specular
Reflective Polarizes film product (sold as DBEF), both of which are
available from Minnesota Mining and Manufacturing Company. Furthermore,
at least the second light redirecting element 28 and the reflective
polarizes 30, and potentially the first light redirecting element 26,
may be combined into a single optical element. International
Patent Publication WO 01/27528 published 19 April 2001,
describes several such
2 S combined optical structures.
With lightguides used for backlighting, such as the
lightguide 16, it is common for there to be non-uniformities in the



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light output from the lightguide. These non-uniformities can frequently
be concentrated near the input surface 21. To mask non-uniformities,
which are generally considered a defect, a diffuser that covers the
output surface of the lightguide is typically used. However, a diffuser
tends to reduce the overall brightness of the display and may not
adequately mask all of the defects.
As described above, in the illumination system 10, the first
light redirecting element 26 is arranged as a turning film, and may have
a structure as shown in FIG. 2. Referring once again to FIG. 2, the
film contains a pattern 42 of optical structures 40 (prisms) that are
arranged to have an out-of-phase varying amplitude. For a turning film
application, the pattern 42 is formed on a surface that is the light
input surface of the film. However, in other applications several of
which will be described herein, the pattern 42 may be formed on a top
andJor bottom surface of a wedge, slab or film. For the turning film
application illustrated in FIG. 1, in addition to the prisms formed on
the first surface 32 of the first light redirecting element 26, the
second surface 34 may be formed with optical structures.
Continuing with the discussion in connection with FIG. 2,
2 0 the first light redirecting element 26 has a first edge 36 and a second
edge 38. The optical structures 40 extend from the first edge 36 toward
the second edge 38 in the pattern 42. Each optical structure 40 may
have a number of characteristics, such as amplitude, period and aspect
ratio of the peaks 44 and valleys 46. The pattern 42 may also have
2 5 characteristics, such as for example, a pitch, p, between optical
structures 40. The structures 40 in FIG. 2 are shown having amplitude
variation. In application of the first light redirecting structure 26,



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the grooves may be arranged such that variation in their amplitude is
perpendicular to the lightsource l2 (FIG. 1).
With continued reference to FIG. 2, it is observed that
within the pattern 42, the optical structures 40 are formed with a
larger amount of amplitude variation at the first edge 36, and this
amplitude variation decreases in magnitude toward the second edge 38.
The larger amount of amplitude variation in the optical structures 40
produces more optical power along the groove axis because of the higher
surface slopes. The optical power of this pattern then decreases as a
function of the distance from the first edge 36. This arrangement of
the optical structures 40 and the pattern 42 is purposeful. As noted,
non-uniformities in the output of lightguide 16 may be concentrated near
the input surface 21 while there may be less non-uniformity farther from
the input surface 21. Thus, the optical structures 40 and the pattern
42 are arranged to provide more diffusion near the first edge 36. In
application, the first edge 36 will be disposed substantially adjacent
the input surface 21 of the lightguide 16. The pattern 42 has a pitch,
p, which may be uniform or variable, and the amplitude of the optical
structures 40 may decrease to naught toward the second edge 38. This
2 0 pattern, as will be discussed in more detail below, may be produced with
any tool shape.
It should be appreciated that using ray tracing and other
analysis techniques, it is possible to determine particular arrangements
for the optical structures 40 and the pattern 42 that best correct
2 5 particular observed non-uniformities in the output of the lightguide 16.
That is, one or more of the characteristics of the optical Structures 40
and the pattern 42 may be tailored to correct a particular non-



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uniformity. As described above, in connection with first light
redirecting element 26, the optical structures 40 and the pattern 42
provided optical power to the output of the lightguide 16 near the input
surface 21 in order to mask non-uniformities that may occur near the
input surface 21. Less or no optical power is provided away from the
input surface 21 as fewer or less intense non-uniformities are typically
observed from the lightguide 16 farther from the input surface 21. In
this manner, optical power is provided where most needed to mask or
soften non-uniformities, while less optical power is provided where
there may be less non-uniformity to mask. Moreover, optical power may
be added virtually anywhere to the output of the lightguide by adding
optical structures and/or varying the characteristics of the optical
structures. Furthermore, the addition of optical power need not be
uniform. Instead, optical power may be added, as necessary, to discrete
regions of the lightguide output if necessary to help mask a defect or
create a particular optical effect.
Some lightguides include a pattern of diffuse dots on a back
surface of the lightguide. Light incident to one of the dots is
diffusely scattered by the diffuse dot, and a portion of this reflected
light is caused to exit the light guide. In spite of the diffuse nature
of this method of extracting light from the lightguide, the pattern of
dots may itself be visible in the lightguide output. Thus, to hide the
dot pattern, additional diffusion is typically provided.
With reference to FIG. 3, a film 50 has a surface 52 which
2 5 is formed to include a plurality of optical structures 54 disposed in a
pattern 56. The optical structures 54 are arranged essentially to
replace the diffuse dot pattern for providing extraction of light from



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the lightguide. While shown in FIG. 3 as ellipses, the optical
structures 54 are not collectively limited to any particular shape nor
are they limited to any one particular shape within the pattern 56.
Therefore, the optical structures 54 may be prisms, lines, dots,
squares, ellipses, circles, diamonds or generally any shape or
combinations of shapes. Moreover, the optical structures 54 may be made
very small in size and may be spaced very closely together within the
pattern 56, much more so than the dots within a diffuse dot pattern may
be size and spaced. For example, the optical structures may have a size
up to the size typical of that used for diffuse dots, but preferably
will be smaller than the acuity of the human eye, and may be spaced
within about 50-100 m of each other. This very small size and close
spacing of the optical structures 54 eliminates or reduces the need for
diffusion in the output of the lightguide that is ordinarily necessary
to hide the pattern of diffuse dots.
Referring to FIG. 4, an optical film 51 has a surface 53
which is formed with a plurality of optical structures 55 disposed in a
pattern 57. In this embodiment of the invention, the optical structures
55 are formed as circles or dots. FIG. 5 illustrates a lightguide wedge
2 0 59 with a back surface 61 that is formed with optical structures 63
disposed in a pattern 65. The optical structures again are illustrated
as circles or dots, but it will be appreciated that the optical
structures may take on virtually any configuration.
The invention permits and provides for the changing of the
slope of the lightguide at a micro-level. That is, the slope of the
lightguide may be locally increased or decreased by the addition of
optical structures at the micro-level. When a light ray hits a higher



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positive slope, it will be extracted from the lightguide faster than if
it hit the nominal wedge angle.
While so far discussed in terms of optical films, the
invention has application to the lightguide wedge itself. Referring to
FIGS. 6 and 7, a lightguide 60 has an input surface 62, an output
surface 64 and a back surface 66. The input surface 62 is arranged to
be disposed adjacent a light source (not depicted) to provide a source
of light incident to the input surface 62. The light incident to the
input surface 62 is extracted out of the output surface 64 as a result
of frustrated TIR within the lightguide 60. As discussed above, it is
common for there to be non-uniformities in the light output from the
lightguide 60, particularly near the input surface 62.
FIG. 7 illustrates the addition of optical power to the back
surface 66 of the lightguide 60 and the adjustment in intensity
extending away from the input surface 62. As shown in FIG. 6, the back
surface 66 is formed with in-phase optical structures 68 arranged to
enhance extraction near the input surface 62 and to taper to naught away
from the input surface 62. The pattern can also be non-tapering, i.e.,
constant, over the entire surface, increasing from naught, randomly
2 0 varying, or distributed in discrete regions. It is also possible for
the optical structures to be out-of-phase, such as optical structures
68' formed in a back surface 66' of the lightguide 60' shown in FIG. 8.
It will be appreciated that patterns of optical structures may also be
formed in the output surface 64 either separately or in conjunction with
2 5 a pattern formed in the back surface 66 -- such embodiments of the
inventions being described more fully below and particularly in
connection with FIGS. 15 and 16. Returning to the present discussion, a



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purpose of providing the optical structures is to achieve an effect that
minimizes non-uniformities of the lightguide output wherever they may
occur. For example, the lightguide 60 shown in FIGS. 6 and 8 may have
non-uniformities that appear primarily adjacent the input surface 62,
which would suggest adding optical structures that have more optical
power near the input surface 62.
with particular reference to FIG. 7, the optical structures
68 may be formed on a surface 72 of an optical film 70. The optical
film 70 may then be coupled to the wedge structure of the lightguide 60
using ultraviolet (W) curing, pressure sensitive or any other suitable
adhesive. Alternatively, the wedge may be molded in bulk to include the
optical structures 68 in the back surface 66.
As will be more generally appreciated from the foregoing
discussion, virtually any configuration of optical structures may be
formed into an optical film, and the optical film coupled, for example
by bonding, to a lightguide or other bulk optical element. For example,
glare reduction, anti-wetout, Fresnels, and virtually any other
structure that may be formed in a surface of an optical film may be
easily replicated into the film and then the film coupled to another
optical element.
Films incorporating programmed optical structures may be
manufactured using a microreplication process. In such a manufacturing
process, a master is made, for example by cutting the pattern into a
metal roll, and the master is used to produce films by extrusion, cast-
2 5 and-cure, embossing and other suitable processes. Alternatively, the
films may be manufactured by compression or injection molding, casting
or roll forming. A preferred apparatus and method for microreplication

.~..> u~~...~~, .
CA 02413700 2005-08-12
WO 02/0.858 PCT/USO1/2129.1
-15-
is described in International Patent Publication WO 00/48037
published 17 August 2000.
As an example of the above-described feature of the
invention, and with reference to FIG. 9, a linear Fresnel lens or prism
80 has a substantially planar first surface 82 and a second surface 84.
The second surface 84 is formed with lens structures 86 and superimposed
on the lens structures 86 are additional optical structures 88. The
optical structures 88 have characteristics, such as amplitude, period,
and aspect ratio, which vary from a first edge 90 of the lens 80 to a
second edge 92 of the lens 80. The lens 80 may be formed in bulk, or as
shown in FIG. 9, the lens structures 86 including the optical structures
88 may be formed on a film 94 that is then bonded to a bulk optical
substrata 96. Depending on the application, the first surface 82 may be
arranged as an input surface and the second surface 84 as an output
surface, and vice-versa.
FIGS. 10 and 11 illustrate schematically a circular lens 81
that includes a first surface 83 and a second surface 85. The second
surface 85 is formed to include lens structures 87, for example,
circular Freenel lens structures, and superimposed over the lens
structures B7 are additional optical structures 89. The optical
structures 89 have characteristics, such as amplitude, period, and
2 5 aspect ratio, which may vary, for example, from an outer circumference
of the lens B1 to the center of the lens 81.
Referring now to FIG. 12, shown graphically is a film 100



CA 02413700 2002-12-18
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-16-
containing a varying amplitude pattern 102 of optical structures 108
formed using a " v" shaped cutting tool. The pattern 102 may be formed
on a top and/or bottom surface of the film 100. Likewise, the pattern
l02 may be formed in a wedge or slab. The film 100 has a first edge 104
and a second edge 106. The optical structures 108 extend from the first
edge 104 toward the second edge 106 arranged in the pattern 102. Each
optical structure 108 may have a number of characteristics, such as
amplitude, period and aspect ratio. The pattern 102 may also have
characteristics, such as for example, a pitch, p, defining a spacing
between optical structures 108. The optical structures 108 in FIG. 12
are shown having amplitude variation. In application of the film 100,
the grooves may be arranged such that the variation in amplitude is
perpendicular, parallel or at an angle to a lightsource of the
lightguide incorporating the film 100.
with continued reference to FIG. 12, it is observed that
within the pattern 102, the optical structures 108 are formed with
larger amplitude at the first edge 104 and decrease in amplitude toward
the second edge 106. The larger amplitude produces more optical power
along the groove axis because of the higher surface slopes. The optical
2 0 power of this pattern then decreases as a function of the distance from
the first edge 104. This arrangement of the optical structures 108 and
the pattern 102 is purposeful.
with reference to FIGS. 13 and 14, films 110 and 112, are
shown respectively. Each film 110 and 112 has characteristics like film
100, and like reference numerals are used to describe like elements
therebetween. As opposed to the pattern created by using a " V" shaped
tool, the film 110, FIG. 13, has a pattern 114 of optical structure 116



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-17-
that is formed using a tool having a curve or arc configuration. The
film 112, FIG. 14, has a pattern 118 of optical structures 120 that is
formed using a flat nose tool. The patterns 114 and 118 are arranged as
described to provide optical power in the surface or surfaces of the
films 110 and 112. It will be appreciated that virtually any tool
configuration may be used with the particular tool being selected to
achieve a desired amount and form of optical power in the surface~or
surfaces of the film.
In the lightguide 121 illustrated in FIGS. 15 and 16, a
1 0 first pattern 122 of optical structures 124 is formed in a bottom
surface 126 and a second pattern 128 of optical structures 130 is formed
in a top surface 132 of the wedge 134. For purposes of illustration
only, the optical structures 124 axe shown in FIG. 15 to extend only
partially across the bottom surface 126, and the optical structures 130
are shown in FIG. 15 to extend only partially across the top surface
132. It will be appreciated that the optical structures 124 and the
optical structures 130 will in most cases extend across the entirety of
the bottom surface 126 and the top surface 132, respectively. The first
pattern. 122 may be arranged to facilitate the extraction of light from
2 0 the wedge 134, while the second pattern 128 may be arranged to mask non-
uniformities in the light output from the wedge. It will be
appreciated, however, that the patterns implemented in the wedge 134
will depend on the desired light output to be achieved from the wedge
134. Moreover, as described above, the patterns 122 and 128 may be
2 5 formed first in optical films that are later coupled to the wedge, for
example, by bonding. In another construction, surfaces 122 and 128 are
formed in the wedge by injection molding or casting.



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-18-
As is appreciated from the foregoing discussion, and in
accordance with the preferred embodiments of the invention, a lightguide
may be formed with optical structures, e.g., " V" grooves, in either a
first surface, a second surface or both. Whether the first surface or
the second surface is an input surface relates to the orientation of the
surface with respect to a light source. The optical structures may be
uniformly or randomly spaced, and may have various other
characteristics. Thus, the invention has application to lightguides and
backlight systems for a variety of applications. One example of an
application is a backlight system that extracts light by the frustration
of total internal reflection where the lightguide is formed with optical
structures in either a back surface and/or an output surface thereof.
Still another example is a backlight system that has a lightguide that
uses a pattern of dots to extract light ad includes optical structures
formed in either or both of its back and output surfaces. These and
other examples are described in more detail below.
Referring to FIG. l7, a backlight 140 is illustrated and
includes a light source 142 adjacent an input edge 143 of a wedge
lightguide 144. A back reflector 146 is disposed adjacent a back
2 0 surface 154 of the lightguide 144, and a turning film 148 is disposed
adjacent an output surface 150 of the lightguide 144. The back surface
154 is formed with optical structures 152. The optical structures 152
may be grooves formed in the back surface 154, and are shown as such in
FIG. 16. The grooves shown in FIG. 17 are " V" grooves and have a prism
2 5 angle of about 90 degrees, but prism angles ranging from 60 degrees -
120 degrees may be used. Shapes other than " V" grooves may also be
used for optical structures 152. Furthermore, each optical structure

CA 02413700 2005-08-12
WO U2/0-t8i8 PCT/USU1/2129.t
-19-
may be formed to have a height that varies along its length from a
nominal value. This variation may have a wavelength, which may be in
the range of about 1 m - 1000 m, preferably be leas than about 14,0 m.
Such structures are disclosed and described in International Patent
Publication GTO 99/42$61 published 26 August 1999.
The optical structures 7.52 are shown oriented substantially
perpendicular to the light source 142. It will be appreciated that the
optical sti-ucturea 152 may be oriented parallel to the light source 142
ox at an angle between 0 degrees - 90 degrees to the light source 142.
The turning film 148 may be any suitable prismatic turning
film. ~ For example, the turning film 148 may be formed as described in
the aforementioned International Patent Publication WO 01/27663.
The back surface 154 is formed to include the optical
structures 152. This results in some additional light being extracted
from the lightguide 144 through the output surface 150 as compared to
the light that is extracted from the back surface 154. A portion of the
light exiting the back surface 154 will encounter the back reflector 146 '
and will be reflected back through the lightguide 144 and the output
surface 150.
Referring now to FIG. 18, a backlight 140 is illustrated
that is similar in construction to the backlight 140, and like reference
numerals are used to designate like elements. Primed reference numerals
are used to designate elements that are altered from the backlight

CA 02413700 2005-08-12
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-20-
construction shown in FIG. 17. The backlight 140' includes a light
source 142 adjacent an input edge 143 of a wedge lightguide 144'. A
back reflector 146' is disposed adjacent a back surface 154' of the
lightguide 144', and a turning film 148 is disposed adjacent an output
surface 150' of the lightguide 144'. The output surface 150' is formed
with optical structures 152'. The eptical structures 152' may be
grooves formed in the output surface 150', and are shown as such in FIG.
17. The grooves shown in FIG. 18 are ° V" grooves and have a prism
angle of about 90 degrees, but prism angles ranging from 60 degrees
120 degrees may be used. Shapes other than ~~ V" grooves may also be
used for optical structures 152', Furthermore, each optical structure
152' may be formed to have a height that varies along its length from a
nominal value. This variation in height may have a wavelength, which
may be in the range of about 1 m - 1000 m, but for lightguide
~ applications will preferably be less than about 140 m. Such structures
are disclosed and described in the aforementioned International
Patent Publication WO 99/42861.
The optical structures 152' are shown oriented substantially
perpendicular to the light source 142'. It will be appreciated that the
optical structures 152' may be oriented parallel to the light souxce
142' or at an angle between 0 degrees - 90 degrees to the light source
142.
Forming the output surface 150' to include the optical
structures 152' results in additional light being extracted from the
lightguide 144 through the back surface 154' as compared to the output
surface 150'. Some light is also extracted from the output surface
150'. The portion of the light exiting the back surface 154' will

~.~rw_. ~" _.. . . .. ...m_....~.~.Y, ~w,;~..."~~ - ,.~.
CA 02413700 2005-08-12
WO 02/ILi858 PCT/US01/2129-L
-21-
encounter the back reflector 146' and will be reflected back through the
lightguide 144' and the output surface 150. Therefore, with the
backlight 140', it may be desirable to directly secure the back
reflector 146' to the back surface 154'. This may be accomplished by
laminating the back reflector 146' to the back surface 154'. Such an
arrangement for the back reflector 146' is disclosed and described in
International Patent Publication WO 01/27529 published
19 April 2001.
Alternatively, the back reflector may be formed on the back surface
using a vapor deposition process. In embodiments in which the reflector
is directly secured to the back surface of the lightguide, it will be
appreciated that the reflector should be both specular and highly
efficient with very low absorption.
As described above, variation is added to a characteristic
of the optical structures 152 and 152' formed respectively in the back
surface or the output surface of the lightguide, e.g., variation in the
amplitude of the optical structures, to reduce non-uniformities in the
2 0 output of the backlight 140 and 140', respectively. Tt is possible to
provide similar variation in the optical structures by other methods,
such as by bead blasting the optical structures, however forming the
grooves with the described variation in prism height provides a
controllable, predictable and hence preferred method of reducing non-
2 5 uniformities in the output of the backlight.
FIG. 19 illustrates light output in a viewing cone disposed
above an output of the backlight 140, i.e., the light exiting the



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-22-
backlight 140 from an output surface of the turning film 148. What may
be determined from the illustrated light output is the on-axis
luminance, the maximum luminance, the integrated intensity, the
horizontal distribution or horizontal half-angle and the vertical
distribution or vertical half-angle. FIG. 20 provides a similar
distribution for the backlight 140'. Clearly noticeable is that the
output of backlight 140' has a reduced horizontal distribution and a
slightly increased vertical distribution. Overall integrated intensity,
or the total amount output light from the backlight 140 and 140' is
about the same, although on-axis luminance and maximum luminance is
substantially increased for the backlight 140' as compared to the
backlight 140. Appreciated from the FIGS. 19 and 20, is that the
arrangement of optical structures in the lightguides 140 and 140',
respectively, will have an effect on the output of the backlight system.
In the backlight 140', the lightguide 144' with optical structures 152'
formed in its top surface, additional collimation of the light output of
the backlight 140' is achieved as compared to the backlight 140.
Furthermore, because optical structures 152' may be formed with varying
characteristics, as described above, the light output from the backlight
2 0 140' may be made uniform without additional optical films or other
devices, such as diffusers.
There are additional advantages associated with providing
the optical structures 152', including varying characteristics, in the
output surface 150' of the lightguide 140'. One such advantage relates
2 5 to the interface of the output surface 150' with the turning film 148.
With the optical structures 152' being formed in the output surface
150', there will be relatively few points of contact between the prisms



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-23-
of the turning film 148 and the output surface 150'. This may result in
a decrease in the optical defect generally referred to as wet-out. As
mentioned above, providing variation in the formation of the optical
structures 152' helps also to mask defects in the output of the
backlight making the light output more uniform. Therefore another
advantage of providing the optical structures 152' in the output surface
150' may be the elimination of a diffuser film in the overall backlight
system. Because the optical structures 152' provide light collimation,
as may be observed from FIG. 20, it is possible, in accordance with the
1 0 invention, to provide a backlight system that requires fewer sheets of
optical film as compared to typical backlight systems.
Illustrated in FIG. 21, are a lightguide 151, a turning film
153, an LCD display 154 and a back reflector 155. Light is extracted
from the lightguide 151 from both the top surface 161 and the back
surface 157. It is possible that strong Fresnel reflections 156 between
the back reflector 155 and the back surface 157 may trap a substantial
portion of the light extracted from the back surface 157. This light is
ultimately lost leading to inefficiency. To improve this situation,
illustrated in FIG. 22, the reflecting surface 158 of the back reflector
2 0 155' may be formed with optical structures 159. The optical structures
159 may be facets, grooves or other shaped structures. The optical
structures 159 help 1to reduce the specular component of reflection from
back reflector 155' and to direct more light up through the lightguide
151, thus increasing its efficiency. A suitable back reflector
2 5 including optical structures is the enhanced diffuse reflector (EDR)
film product sold by 3M. One of skill in the art will appreciate that
the principle taught in FIG. 22 may be applied to virtually any



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-24-
backlight, including without limitation backlight 140 and backlight
systems in accordance with the additional preferred embodiments herein
described.
Several adaptations, enhancements and modifications of the
backlight systems have been described above. Still others can be
appreciated and are within the scope of the invention. It will be
appreciated that the particular arrangement of the backlight system will
depend on the application for which it is intended. To illustrate the
adaptability of the present invention, several examples are shown and
described in connection with FIGS. 23-28.
Grooves in the Back Surface of the lightguide
In FIG. 23, a backlight 160 includes a light source 162, a
wedge lightguide 164, a back reflector 166, a turning film 168 and an
optional additional optical film 170. The lightguide 164 has an output
surface 165 and a back surface 172 that is formed with optical
structures similar to optical structures 152 shown in connection with
the lightguide 144 in FIG. 16. The optical structures may be formed
directly into the lightguide 164 by injection molding or casting.
2 0 Alternatively, the optical structures may be formed in a light
transmissive film that is laminated to the back surface 172 of the
lightguide 164.
with optical structures formed on the back surface 172 of
the lightguide 164 additional light exits the lightguide 164 through the
output surface 165 as compared to the back surface 172. The light
exiting the back surface 172, however, encounters the back reflector
166, and is reflected back through the lightguide 164. A suitable



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-25-
reflector including optical structures is a grooved diffuse reflector.
In accordance with additional aspects of the backlight 160,
the turning film 168 may be formed to include a diffusive structure in
its output surface 176. The optional optical film 170 may be a
brightness enhancing film, such as aforementioned BEFIII optical film,
the Diffuse Reflective Polarizes film product (sold as DRPF) or the
Specular Reflective Polarizes film product (sold as DBEF), all of which
are available from Minnesota Mining and Manufacturing Company.
Grooves in the Output Surface of the lightguide
In FIG. 24, a backlight 180 includes a light source 182, a
wedge lightguide 184, a back reflector 186, a turning film 188 and an
optional optical film 190. The lightguide l84 has an output surface 192
that is formed with optical structures similar to optical structures
152' shown in connection with the lightguide 144' illustrated in FIG.
17. The lightguide 184 may be formed by injection molding or casting so
as to include the optical structures in the output surface 192.
Alternatively, the optical structures may be formed in a light
transmissive film that is laminated to the output surface 192 of the
lightguide 184. Such an arrangement potentially increases manufacturing
flexibility and reduces manufacturing costs by simplifying mold design
for the lightguide 184. Instead of having a unique mold for each
lightguide, lightguides may be adapted in accordance with the invention
by laminating a surface of the lightguide with the optical film formed
with the optical structures.
With optical structures formed on the output surface 192 of
the lightguide 184 an additional amount of light exits the lightguide



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-26-
184 from the output surface 192 as compared to the amount of light
exiting the lightguide from a back surface 193. The light exiting the
back surface 193, however, encounters the back reflector 186, and is
reflected back through the lightguide 184. To ensure a high percentage
of the light exiting the back surface 193 is reflected back through the
lightguide 184, the back reflector 186 is preferably directly secured to
the back surface 193. This may be accomplished by laminating a mirror
or mirror film to the back surface 193 or by vapor deposition coating
the back surface 193. When directly secured to the back surface 193,
the back reflector should be specular and highly efficient.
In accordance with additional aspects of the backlight 180,
the turning film 188 may be formed to include a diffusive structure in
its output surface 196. The optical film 190 may be a brightness
enhancing film, such as aforementioned BEFIII optical film, the Diffuse
Reflective Polarizer film product (sold as DRPF) or the Specular
Reflective Polarizer film product (sold as DBEF), all of which are
available from Minnesota Mining and Manufacturing Company.
In FIG. 25, a backlight 220 includes a light source 222, a
wedge lightguide 224, a back reflector 226 and a turning film 228. The
lightguide 224 has an output surface 230 that is formed with optical
structures (not depicted). The optical structures may have a varying
pattern, such as described in the aforementioned United States Patent
Application entitled " Optical Film,° formed using a cutting tool
of any
suitable shape. The optical structures may be formed directly in the
lightguide 224 by injection molding or casting, or alternatively, the
optical structures may be formed in a light transmissive film that is
laminated to the output surface 230 of the lightguide 224.



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
_27_
With optical structures formed on the output surface 230 of
the lightguide 224 an additional amount of light exits the lightguide
224 through the back surface 232 as compared to the amount of light that
exits through the output surface 230. This light encounters the back
reflector 226, and is reflected back through the lightguide 224. A
suitable reflector may be a grooved diffuse reflector. The optical
structures may also provide for masking of non-uniformities, and thus'
eliminate the need for a diffuser in the backlight system.
Also, because the optical structures may also provide
collimation of the light exiting the lightguide (see FIG. 20), it is
possible, in accordance with the invention, to provide a backlight
system that requires fewer sheets of optical film as compared to typical
backlight systems. In the embodiment shown in FIG. 25 there is a
single, optional, optical film 238, which may be the Diffuse Reflective
Polarizer film product (sold as DRPF) or the Specular Reflective
Polarizer film product (sold as DBEF) available from Minnesota Mining
and Manufacturing Company.
Recycling Backlight Systems
In FIG. 26, a backlight 200 includes a light source 202, a
wedge lightguide 204, a back reflector 206, and one or more additional,
optional optical films 210 and 212. The lightguide 204 has a back
surface 214 that is formed with optical structures similar to optical
structures 152 shown in connection with the lightguide 144 in FIG. 17.
The optical structures may be formed directly in the lightguide 204 by
injection molding or casting. Alternatively, the optical structures may
be formed in a light transmissive film that is laminated to the back

m",".",~.~,,~..".a,~..~..,.. v ~~ ,.~ ~. _ ri """."~,~..ry,.
CA 02413700 2005-08-12
WO 02/04858 PCTNSO1/2129.t
-28-
surface 214 of the lightguide 204.
The optical structures formed on the back surface 214 of the
lightguide 204 facilitate the extraction of light from the lightguide
2D4. The optical structures may therefore allow for the elimination of
the diffuse dot pattern typically used to extract light from the
lightguide. Some light exits the back surface 214, and this light
encounters the back reflector 206, and is reflected back through the
lightguide 204. A suitable back reflector is the enhanced diffuse
reflector (EDR) film product sold by 3M.
1 0 Elimination of the dot pattern for. extraction of light from
the lightguide 204 may reduce the need to add diffusion to mask the
appearance of the dot pattern in the output of the backlight 200. The
optional optical films 210 and 212 may be brightness enhancing films,
such as the aforementioned BEFIII optical film product arranged in a
crossed arrangement; Diffuse Reflective Polarizer film product (sold as
DRPF) the Specular Reflective Polarizer film product (sold as DBEF)
and/or various combinations thereof and all of which are available from
Minnesota Mining and Manufacturing Company.
In FIa. 27, a backlight 240 includes a light source 242, a
2 4 wedge lightguide 244, a back reflector 246, a diffuser 248 and first and
second optional additional optical films 250 and 252. The back
reflector 246 is preferably secured to a bank surface 254 of the
lightguide 214 using a dot patterned adhesive, such as described in the
aforementioned International Patent Publication L~10 01/27529.
2 5 The adhesive is therefore
arranged in a dot pattern typical of an extraction dot pattern.
The lightguide 244 has an output surface 255 that is formed



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-29-
with optical structures (not depicted). The optical structures may have
a varying pattern as described above. The optical structures may be
formed directly in the lightguide 244 by injection molding or casting,
or alternatively, the optical structures may be formed in a light
transmissive film that is laminated to the output surface 255 of the
lightguide 244.
The optical structures including the varying pattern, as
described, may eliminate the need for a diffuser, such as the diffuser
248, to mask the dot pattern, as well as other non-uniformities in the
output of the backlight 240. As such, the diffuser 248 is optional.
When used, the optional optical films 250 and 252 may be brightness
enhancing films, such as the aforementioned BEFIII optical film product,
arranged in a crossed arrangement, the Diffuse Reflective Polarizes film
product (sold as DRPF) or the Specular Reflective Polarizes film product
1 5 (sold as DBEF), all of which are available from Minnesota Mining and
Manufacturing Company.
Pseudo-Wedge Backlight System
Referring now to FIG. 28, a backlight 260 includes a light
2 0 source 262 and a pseudo-wedge lightguide 264. The pseudo-wedge
lightguide 264 includes a first surface 266 and a second surface 268.
The first surface may be formed with optical structures 270, such as
optical structures 152 described in connection with fIG. 17. The second
surface is formed with faceted groove structures 272 that are arranged
2 5 to be parallel to the light source 262. The faceted groove structures
272 facilitate extraction of light from the lightguide by enhancing the
frustration of total internal reflection. Not shown, the backlight 260



CA 02413700 2002-12-18
WO 02/04858 PCT/USO1/21294
-30-
will also include a back reflector disposed adjacent the second surface
268.
The faceted groove structures 272 may have variable angle
features. Each individual facet has a facet angle. When the faceted
groove structures 272 include a variable angle feature, the individual
facet angles vary from facet to facet. This arrangement of the faceted
groove structures 272 may reduce the appearance of nonuniformities in an
output of the backlight 260.
While the lightguide 264 is shown as a slab structure, the
lightguide 264 may be wedge. Furthermore, the faceted groove structures
272 may be formed directly in the lightguide 264, for example by molding
or casting, or the faceted groove structures may be formed in an optical
film that is laminated to a slab or wedge lightguide. The faceted
groove structures may also vary in density as a function of distance
from the light source 262.
Still other modifications and alternative embodiments of the
invention will be apparent to those skilled in the art in view of the
foregoing description. This description is to be construed as
illustrative only, and is for the purpose of teaching those skilled in
2 0 the art the best mode of carrying out the invention. The details of the
structure and method may be varied substantially without departing from
the spirit of the invention, and the exclusive use of all modifications
which come within the scope of the appended claims is reserved.

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date 2007-01-09
(86) PCT Filing Date 2001-07-05
(87) PCT Publication Date 2002-01-17
(85) National Entry 2002-12-18
Examination Requested 2002-12-18
(45) Issued 2007-01-09
Deemed Expired 2009-07-06

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Request for Examination $400.00 2002-12-18
Registration of a document - section 124 $100.00 2002-12-18
Application Fee $300.00 2002-12-18
Maintenance Fee - Application - New Act 2 2003-07-07 $100.00 2002-12-18
Maintenance Fee - Application - New Act 3 2004-07-05 $100.00 2004-06-23
Maintenance Fee - Application - New Act 4 2005-07-05 $100.00 2005-06-27
Maintenance Fee - Application - New Act 5 2006-07-05 $200.00 2006-06-21
Final Fee $300.00 2006-10-23
Maintenance Fee - Patent - New Act 6 2007-07-05 $200.00 2007-06-18
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
3M INNOVATIVE PROPERTIES COMPANY
Past Owners on Record
COBB, SANDFORD
GARDINER, MARK E.
KRETMAN, WADE D.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Abstract 2002-12-18 2 67
Claims 2002-12-18 6 146
Drawings 2002-12-18 12 438
Description 2002-12-18 30 1,240
Representative Drawing 2002-12-18 1 12
Cover Page 2003-03-26 1 42
Claims 2005-08-12 5 187
Description 2005-08-12 30 1,245
Representative Drawing 2006-12-08 1 15
Cover Page 2006-12-08 1 46
PCT 2002-12-18 6 201
Assignment 2002-12-18 4 226
PCT 2002-12-19 2 65
Prosecution-Amendment 2005-02-16 2 66
Prosecution-Amendment 2005-08-12 14 577
Correspondence 2006-10-23 1 34