U.S. patent application number 11/052055 was filed with the patent office on 2006-04-13 for system for and method of optically enhancing video and light elements.
Invention is credited to Steven De Keukeleire, Karim Meersman, Katrien Noyelle, Robbie Thielemans, Herbert Van Hille.
Application Number | 20060077307 11/052055 |
Document ID | / |
Family ID | 35432005 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060077307 |
Kind Code |
A1 |
Thielemans; Robbie ; et
al. |
April 13, 2006 |
System for and method of optically enhancing video and light
elements
Abstract
A video and/or lighting system including a lighting module and
at least one optical element situated in front of the lighting
module that includes an array of lighting elements, wherein the
video and/or lighting system is provided with releasable attaching
means for attaching the optical element to the lighting module, for
a modular setup of said video and/or lighting system.
Inventors: |
Thielemans; Robbie;
(Nazareth, BE) ; Van Hille; Herbert; (Ismaning,
DE) ; Meersman; Karim; (Kortemark, BE) ; De
Keukeleire; Steven; (Deinze, BE) ; Noyelle;
Katrien; (Gullegem, BE) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Family ID: |
35432005 |
Appl. No.: |
11/052055 |
Filed: |
February 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60616200 |
Oct 7, 2004 |
|
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|
Current U.S.
Class: |
348/800 ;
348/E5.135; 348/E9.012; 348/E9.024 |
Current CPC
Class: |
G09G 2370/045 20130101;
G09G 3/32 20130101; H05B 47/10 20200101; G09F 19/22 20130101; G09F
9/30 20130101; H04N 13/305 20180501; G06F 3/1431 20130101; G09G
3/2014 20130101; G09G 2370/04 20130101; G09F 9/33 20130101; H04N
9/12 20130101; G06F 3/1446 20130101; Y02B 20/40 20130101; G09F
15/00 20130101; G09G 5/003 20130101; G09G 2300/026 20130101; G09G
2370/042 20130101; G09G 2360/04 20130101; H05B 47/18 20200101; G09G
3/3611 20130101; H04N 2213/001 20130101; G06F 3/14 20130101; G09F
9/3026 20130101; H04N 5/70 20130101; G09F 27/008 20130101; H04N
9/30 20130101 |
Class at
Publication: |
348/800 |
International
Class: |
H04N 5/70 20060101
H04N005/70 |
Claims
1. A video and/or lighting system comprising a lighting module and
at least one optical element situated in front of said lighting
module that comprises an array of lighting elements, wherein said
video and/or lighting system is provided with releasable attaching
device arranged to attach means for attach said at least one
optical element to said lighting module, for a modular setup of
said video and/or lighting system.
2. The video and/or lighting system according to claim 1, wherein
said releasable attaching means comprises a clicking system.
3. The video and/or lighting system according to claim 2, wherein
said clicking system comprises of one or more latches projecting
from the back of said optical element and of complementary latch
lips provided in the front of said lighting module.
4. The video and/or lighting system according to claim 1, wherein
said optical element comprises an array of lenses that are
separated from each other with light blocking elements, and wherein
said latches project from contrast enhancing elements.
5. The video and/or lighting system according to claim 1, wherein
the optical element is provided in a carrying structure comprising
said releasable attaching device.
6. The video and/or lighting system according to claim 1, wherein
said releasable attaching device comprises bolts.
7. The video and/or lighting system according to claim 1, wherein
said releasable attaching device comprises a releasable
adhesive.
8. The video and/or lighting system according to claim 1, including
a plurality of different corresponding optical elements arranged to
be used with said lighting module.
9. The video and/or lighting system according to claim 1, wherein
said optical element is chosen from the group consisting of: a
conventional cylindrical or spherical lens; Fresnel structures;
grating structures; filters; total internal reflection (TIR)
structures; nonlinear optical elements; prismatic structures;
polarizers; pillow optic formations; fiber optic cables; light
pipes; and other types of optical wave guides.
10. The video and/or lighting system according to claim 1, wherein
said optical element is an array of optical elements.
11. A method for optically enhancing a video and/or lighting system
wherein use is made of a lighting module and a set of different
corresponding optical elements, wherein one or more of said optical
elements are attachable in front of said lighting module in a
releasable manner, said method comprising the steps of determining
the environmental use; determining the desired video and/or
lighting effect; choosing an appropriate optical element out of
said set; and attaching said appropriate optical element to the
lighting module in a releasable manner.
12. The method according to claim 10, wherein, after attaching said
appropriate optical element to said lighting module, another
additional desired video and/or lighting effect is determined, in
function of which another appropriate optical element is chosen out
of said set, which appropriate optical element is subsequently
attached in front of said lighting module.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a system for and method of
optically enhancing video and light elements and, more
particularly, to optical elements placed in front of video and
light elements to change or enhance their characteristics.
[0003] 2. Discussion of the Related Art
[0004] Cathode-ray-tubes (CRTs) and primitive projection systems
have long been used to display video and motion pictures.
Conventional incandescent lamps, fluorescent lamps, and neon tubes
were the traditional lighting elements used to illuminate many
large-scale commercial and public signs.
[0005] However, the market is now demanding cheaper and larger
displays that have the flexibility to customize display sizes and
colors, with image and video capability, and that are easy to
install, maintain, and disassemble, especially for use in temporary
venues; these are market specifications that are not possible with
the older technologies.
[0006] Relatively recent advances in the manufacture of light
emitting diodes (LEDs) have made them an attractive light source
for many purposes that previously employed incandescent, halogen,
or strobe light sources. LED light sources have longer life and
higher efficiency, and they are more durable than previously
employed light sources.
[0007] Certain types of LEDs can emit radiation in a Lambertian
pattern. The Lambertian distribution of illumination, which does
not favor any one direction or orientation over another, is the
ideal arrangement for some display uses. One example of use for
which Lambertian illumination is desired is a scoreboard at a
professional sporting event, where fans within the stadium are at
all positions relative to the scoreboard--higher, lower, to the
left, right, in front of, etc.
[0008] When viewing is predicable, such as billboard signs along a
highway, Lambertian light distribution is wasteful, as only persons
in front of and slightly below the sign read the information on the
sign.
[0009] In certain key applications, optical efficiency can be
greatly enhanced by the introduction of a light-directing layer in
front of the LED or other pixel-based displays, in order to
preferentially increase the brightness in a certain direction over
other directions, enhance the contrast to accommodate indoor versus
outdoor applications, or modify the color to create a desired
visual effect.
[0010] In many applications, for example in entertainment venues,
both video and lighting effects are desired. However, different
lighting elements are generally needed for video versus lighting in
order to create the desired effects. What is needed is a means to
generate both video and lighting effects by using the same lighting
system.
[0011] Three-dimensional images and video are becoming more widely
used. To create the more realistic effects and environments
demanded by the virtual reality, simulation, and gaming markets,
life-like images need to be created and displayed. Until recently,
three-dimensional effects were only created by using stereo
viewers, red and blue colored glasses, polarizing glasses, or other
types of devices. Now, through the use of LEDs and holographic,
diffractive or lens array screens, three-dimensional images and
video can be viewed by the naked eye.
[0012] There are many types of optical elements that can be used
for an endless number of current and new applications. These
optical elements are placed in a beam or path of light in order to
change the characteristics of the light passing through the optical
elements. Such optical elements may be as simple as a conventional
cylindrical or spherical lens.
[0013] Other types of optical elements may include Fresnel
structures, grating structures, filters, total internal reflection
(TIR) structures, nonlinear optical elements, such as
Gradient-index (GRIN) lenses, prismatic structures, polarizers,
pillow optic formations, fiber optic cables, and other types of
optical wave guides, as are well known to those skilled in the
art.
[0014] All of these structures receive a light input from a light
source and transmit or reflect the light through the structure or
element, then permit the light to exit from the structure or
element in a somewhat altered state. All of these types of optical
elements either transmit, reflect, diffract, refract, (partially)
absorb or filter out certain wavelengths or polarizations of the
light as it exits the structure or element. By altering the
properties of the light that propagate through the optical element,
desired enhancements or effects can be created. What is needed is a
flexible video and lighting system that can be easily modified to
create a desired visual effect or adapted to a specific environment
of use, such as indoors or outdoors.
[0015] An example of an optically enhanced display system is found
in reference to U.S. Patent Application No. 20020084952, entitled,
"Flat panel color display with enhanced brightness and preferential
viewing angles."
[0016] Said '952 patent application describes a light directing
apparatus formed of an LED array that has RGB light emitting diode
structures arrayed longitudinally along a substrate to form a
plurality of RGB triplet groups and a lenslet array that has a
plurality of lenslet structures positioned adjacent to a respective
one of the RGB triplet groups.
[0017] The lenslet structures include, for each respective RGB
triplet group, a plurality of cylindrical lenses that is indexed to
its respective RGB triplet group. The cylindrical lenses are
longitudinally arrayed in parallel to the respective RGB light
emitting diode structures. This arrangement results in greater
optical efficiency, because light from the LEDs is preferentially
directed in a desired direction where an observer is most likely to
be.
[0018] The '952 patent uses cylindrical lenses to direct light from
light emitting elements. However, in many applications and
environments, other optical elements may be better suited to
changing the viewing angle. For example, altering the viewing cone
of the emission profile produced by the light emitting elements may
also be a desired effect in combination to changing the viewing
angle.
[0019] Additional effects may be desired in combination with
altering the viewing angle, for example, light diffusion, adding
color, or increasing contrast. What is needed is a modular display
system that can easily adapt to specific applications and
environments, yet remain flexible enough to produce desired video
and lighting effects.
SUMMARY OF THE INVENTION
[0020] It is therefore an object of the invention to provide a
modular display system that can act as both a video and a lighting
system.
[0021] It is another object of this invention to provide a flexible
lighting system.
[0022] It is yet another object of this invention to provide a
video and lighting system that can easily be adapted for indoor or
outdoor use.
[0023] It is yet another object of this invention to provide a
modular system that can be used for multiple applications.
[0024] It is yet another object of this invention to provide a
modular system in front of which a variety of optical elements can
be mounted, either independently or in combination, to produce
desired video or lighting effects.
[0025] Thereto the present invention relates to a video and/or
lighting system comprising a lighting module and at least one
optical element situated in front of said lighting module that
comprises an array of lighting elements, wherein said video and/or
lighting system is provided with releasable attaching means for
attaching said at least one optical element to said lighting
module, for a modular setup of said video and/or lighting
system.
[0026] In particular the present invention is a video and/or
lighting system that uses solid state, emissive elements, such as
LEDs, that, when used in conjunction with optical elements, alters
the properties of light that propagate through the optical element
and creates desired enhancements or effects.
[0027] A modular emissive lighting source can be used for several
different applications and in a variety of viewing environments by
the user's changing the type or position of the optical element
that is placed in front of the emissive lighting source.
[0028] For example, a single system of modular emissive lighting
sources can be used to display full-motion video, create magnified,
two-dimensional images, create three-dimensional images, or act as
a light source by the user's changing the optical elements.
Different optical elements can also be used to change the viewing
angle or emission profile, enhance the brightness, contrast, and
color, or enable the system to be used indoors or outdoors.
[0029] The present invention also relates to a method for optically
enhancing a video and/or lighting system wherein use is made of a
lighting module and a set of different corresponding optical
elements, wherein one or more of said optical elements can be
attached in front of said lighting module in a releasable manner,
said method comprising the steps of determining the environmental
use; determining the desired video and/or lighting effect; choosing
an appropriate optical element out of said set; attaching said
appropriate optical element to the lighting module in a releasable
manner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to better explain the characteristics of the
invention the following preferred embodiments and method are
described as an example only, without being limitative in any way,
with reference to the accompanying drawings, in which:
[0031] FIG. 1A illustrates a front view of a lighting module in
accordance with the invention;
[0032] FIG. 1B illustrates a back view of a lighting module in
accordance with the invention;
[0033] FIG. 2 illustrates a lens array of the present
invention;
[0034] FIG. 3A illustrates a front view of a clicking system, with
components separated, that is used for attaching an optical element
array to a lighting module in accordance with the invention;
[0035] FIG. 3B illustrates a second front view of a clicking
system, with components attached, for attaching an optical element
array to a lighting module in accordance with the invention;
[0036] FIG. 3C illustrates a side view of a clicking system for
attaching an optical element array to a lighting module in
accordance with the invention;
[0037] FIG. 3D illustrates a detailed view of a clicking system for
attaching an optical element array to a lighting module in
accordance with the invention;
[0038] FIG. 4A illustrates a one-to-one lighting system with front
optics in accordance with the invention;
[0039] FIG. 4B illustrates a front view of a one-to-one lighting
system with front optics in accordance with the invention;
[0040] FIG. 5A illustrates a lighting system with
contrast-enhancing and viewing angle modifying front optics in
accordance with the invention;
[0041] FIG. 5B illustrates a second embodiment of a lighting system
with contrast-enhancing and viewing angle modifying front optics in
accordance with the invention;
[0042] FIG. 6A illustrates a one-to-many lighting system with front
optics in accordance with the invention;
[0043] FIG. 6B illustrates a detailed view of the lens of a
one-to-many lighting system with front optics array in accordance
with the invention;
[0044] FIG. 7 illustrates a lighting system with thin film front
optics in accordance with the invention;
[0045] FIG. 8 illustrates a lighting system with front optics;
[0046] FIG. 9 illustrates examples of Fresnel lenses in accordance
with the invention;
[0047] FIG. 10 illustrates an example gradient-index lens in
accordance with the invention;
[0048] FIG. 11A illustrates a light pipe of the present
invention;
[0049] FIG. 11B illustrates a light pipe array of the present
invention;
[0050] FIG. 12A illustrates a binary surface relief diffractive
optical element;
[0051] FIG. 12B illustrates a multi-layer surface relief
diffractive optical element;
[0052] FIG. 13 is a flow diagram of a method of optically enhancing
a video and/or lighting system in accordance with the present
invention.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0053] FIG. 1A illustrates a front view of an exemplary lighting
module 100. Lighting module 100 contains a 8.times.11 array of
emissive lighting elements 110. However, lighting module 100 is not
limited in size to 8.times.11 and may be an array of any size.
Lighting module 100 is designed to be combined with other, similar
lighting modules to create a large-scale display.
[0054] FIG. 1B illustrates a back view of an exemplary lighting
module 100.
[0055] FIG. 2 illustrates a lens array 200 that is formed of an
array of rectangular or circular lenses 210, each of which has
curved front and/or back faces. The faces may be, but are not
limited to, planar, spherical, conic aspherical, or polynomial
aspherical shapes. The lenses are manufactured with a material
(e.g., polycarbonate) that exhibits a particular refractive index,
which is used to calculate the focal length of each lens. Lens
array 200 is placed in front of or attached to lighting module 100,
an array of lighting modules 100, or the entire video and/or
lighting display system.
[0056] FIG. 3A illustrates a video and/or lighting system that,
according to the invention, is provided with releasable attaching
means.
[0057] In FIG. 3A to 3D said releasable attaching means consist of
a clicking system 300, in which the two elements are separated.
Clicking System 300 is used for attaching optical element arrays,
such as lens array 200 with shade array 330, to lighting module
100. Shade array 330 blocks sunlight, increases image quality,
improves contrast, and is particularly useful in outdoor
applications where there might be bright sunlight. Clicking system
300 is one embodiment of a means to attach optical element arrays
to lighting module 100. Other embodiments may include the use of a
releasable adhesive, such a releasable glue, to attach an optical
element array to lighting element 100. Yet a further embodiment may
include a clicking mechanism, whereby a latch attaches around
lighting module 100. Yet another embodiment may be an optical
element array attached to lighting module 100 by the use of
bolts.
[0058] It is clear that the optical element or an array thereof can
be placed in a carrying structure that is provided with releasable
attaching means such as said clicking system 300, or that can be
attached to said lighting module 100 in a releasable manner by
means of bolts or the like for the modular setup of said video
and/or lighting system.
[0059] Preferably said video and/or lighting system is also
provided with means for altering the distance between the lighting
elements 110 and said optical element, as this distance is an
important parameter for obtaining a desired visual effect.
[0060] FIG. 3B illustrates a second front view of clicking system
300, in which the two elements are connected via clicking system
300.
[0061] FIG. 3C illustrates a side view of clicking system 300.
[0062] FIG. 3D illustrates Detail B of clicking system 300.
Clicking system 300 includes lens array 200, which is made up of an
array of lenses 340, and, in one embodiment, shade array 330, which
includes a latch 310. Latch 310 clicks into and attaches to a
complementary latch lip 320, which hold lens array 200 onto
lighting module 100.
[0063] The distance between lenses 340 and emissive lighting
element 110 can be set to a specific distance by use of latch 310
of an appropriate length. Clicking system 300 may also be used to
accurately position lenses 340 directly in front of or offset from
emissive lighting element 110.
[0064] FIG. 4A illustrates a one-to-one lighting system with front
optics 400. There is a single lens 340 for each emissive lighting
element 110. The area between emissive lighting elements 110 and
lenses 340 can be filled with air or, more preferably, a material,
such as an optical adhesive, which has a refractive index that has
been chosen to better optically couple the light from emissive
lighting elements 110 into lenses 340. This refractive index match
will decrease the light loss. Examples of optical adhesives include
OP-40 High Performance Optical Adhesive, by DYMAX Corporation, and
Dow Corning's SYLGARD.RTM. 184 Silicone Elastomer. In addition,
non-adhesive optical gels, such as Dow Corning's SYLGARD.RTM. 527
Silicone dielectric gel, can also be used. Although one-to-one
lighting system with front optics 400 is shown with a 5.times.5
array of emissive lighting elements 110, it is representative of
any lighting module 100 of any sized array of emissive lighting
elements 110. Lens array 200 can be of the same, or similar, size
as lighting module 100 and attached to lighting module 100 in a
number of ways, such as by clicking system 300, as is shown in FIG.
3A. Alternatively, lens array 200 may be integrated into a large
sheet. This large sheet can have the size of several lighting
modules 100 or of the entire display system.
[0065] FIG. 4B illustrates a front view of a one-to-one lighting
system with front optics 400.
[0066] FIG. 5A illustrates a lighting system with
contrast-enhancing front optics 500. Lighting system with
contrast-enhancing front optics 500 includes emissive lighting
elements 110 and lens array 200, made up of an array of lenses 340.
In one embodiment, on top of lens array 200, black matrices 510 are
placed. The black area between emissive lighting elements 110 will
increase viewing contrast for the viewer.
[0067] FIG. 5B illustrates a second embodiment of a lighting system
with contrast-enhancing front optics 500 in which shade array 330
is placed on top of lens array 200.
[0068] FIG. 6A illustrates a one-to-many lighting system with front
optics 600. Lens array 200 is placed on top of an array of emissive
lighting elements 110, in one embodiment, by clicking system 300.
There is a plurality of lenses 340 for each emissive lighting
element 110. Therefore, the pitch of lens array 200 is much less
than the pitch of the array of emissive lighting elements 110. In
many instances, it may be more convenient to use a larger lens
array 200 that covers several lighting modules 100.
[0069] FIG. 6B illustrates Detail B of lens array 200 of
one-to-many lighting system with front optics 600.
[0070] FIG. 7 illustrates a lighting system with thin film front
optics 700. In one embodiment, a supporting transparent structure
710 is placed between emissive lighting elements 110 and a thin
film 720. Supporting transparent structure 710 provides the
necessary space between emissive lighting element 110 and thin film
720 so that the optical properties of thin film 720 create the
desired effect. Thin film 720 can be, for example, LSD.RTM. Light
Shaping Diffuser Sheets, by Physical Optics Corporation.
[0071] In another embodiment, supporting transparent structure 710
is placed on top of thin film 720. This protects thin film 720 from
damage or from the elements in an outdoor application. Depending on
the type of thin film 720 used, thin film 720 can be, for example,
glued upon supporting transparent structure 710, which is than
placed in front of emissive lighting elements 110.
[0072] Thin film 720 can also be used in combination with lens
array 200 to produce a combination of desired optical effects.
[0073] This is possible with both one-to-one lighting system with
front optics 400 and one-to-many lighting system with front optics
600.
[0074] In one embodiment, thin film 720 is a surface relief
diffusion film, which is a thin (e.g., less than 1 mm thick) film
whose surface structure is generated in such a way that it will
change the emission profile of emissive lighting elements 110 to
create circles, squares, snowflakes, ellipses, and other effects.
Unlike diffractive optics, thin film 720 has no wavelength
dependency. Thin film 720 is designed according to the
specifications of emissive lighting elements 110 and the desired
optical effect. Additionally, thin film 720 can be a large sheet
the size of several lighting modules 100 or the size of the entire
display and can be either homogenous or exhibit different optical
properties across the film.
[0075] In another embodiment, thin film 720 of uniform color is
used and placed in front of lighting module 100 in order to change
the color of emissive lighting elements 110.
[0076] In yet another embodiment, thin film 720 of a certain
density is used and placed in front of lighting modules 100 in
order to change the contrast. Thin film 720 of this type may also
be used in outdoor applications in order to decrease the brightness
and enhance the contrast, which improves viewing in bright sunlit
environments.
[0077] In yet another embodiment, thin film 720 is a thin plastic
or glass sheet with a specific coating, such as a dichroic coating,
which is a thin film coating that can act as a short wave pass,
long wave pass, bandpass, or notch filter by reflecting unwanted
wavelengths back towards the light source. Another example of a
specific coating is a long-pass coating, which is a thin film
coating that passes all wavelengths longer than the cut off
wavelength and blocks all shorter wavelengths. Yet another example
of a specific coating is a short-pass coating, which is a thin film
coating that passes all wavelengths shorter than the cut off
wavelength and blocks all longer wavelengths. For example, to
increase the thermal stability of lighting module 100, an infrared
(IR) filter could be placed in front of emissive lighting element
110. This IR filter reflects the IR radiation present in the
ambient illumination and thus prevents the IR radiation from
reaching lighting module 100. The use of the IR filter, a
short-pass filter, will increase the thermal stability of the
device, since the IR radiation will not be able to heat lighting
module 100. The image quality is not influenced by the use of such
an IR filter. Other dichroic coatings, however, can improve
visibility and contrast.
[0078] In yet another embodiment, an active element, for example a
photo-chemical element, can be placed in front of lighting module
100. The properties of a photo-chemical element are such that the
density changes as a function of the amount of incident sunlight.
This can be useful to optimize the contrast for each illumination
level when the display is used in an outdoor environment under a
variety of sunlight conditions.
[0079] In yet another embodiment, an active element, for example a
liquid-crystal display (LCD) element, can be placed in front of
lighting module 100. Lighting element 100 can function as a back
light for the LCD panel. By appropriately driving the LCD elements,
a desired optical effect can be created, for example polarizing the
light from emissive lighting element 110.
[0080] FIG. 8 illustrates a lighting system with front optics 800
that is formed of an array of emissive lighting elements 110 and a
lens array 200, which is made up of an array of individual lenses
340. The optical axis 810 of lens 340 is shown, which is the
straight line that is coincident with the axis of symmetry of the
surface of lens 340. D is the distance between the array of
emissive lighting elements 110 and lens array 200. The pitch of an
optical element is the distance between the centers of two adjacent
elements. For example, the pitch, PLED, of the array of emissive
lighting elements 110 is the distance between the centers of two
adjacent emissive lighting elements 110. The pitch, P.sub.lens, of
lens array 200 is the distance between the centers of two adjacent
lenses 340.
[0081] In order to create a virtual image, the pitch of lens array
200 must be much less than the pitch of the array of emissive
lighting elements 110, or P.sub.lens<<P.sub.LED. In this
embodiment, there are several lenses 340 per emissive lighting
element 110, as is further illustrated in FIG. 5A. The pitch,
P.sub.LED, of the array of emissive lighting elements 110 is fixed.
P.sub.lens is designed to avoid or minimize Moire effects, which
those skilled in the art are familiar with. P.sub.lens is chosen to
be as small as possible, in order to minimize Moire effects.
However, it is easier and less expensive to fabricate lens array
200 so that it has a large pitch.
[0082] If lens array 200 and the array of emissive lighting
elements 110 are considered to be a series of apertures, then they
can be considered to be a series of square waves. The Fourier
expansion for a square wave of period P=2L, frequency f=1/2L,
.omega.=2.pi./2L, and the duty factor d=2c/2L is given as: f
.function. ( x ) = c L + 2 .pi. .times. m = 1 .infin. .times.
.times. ( - 1 ) m m .times. sin .times. { m .times. .times. .pi.
.times. c L } .times. cos .times. { m .times. .times. .pi. .times.
.times. x L } = d + 2 .pi. .times. m = 1 .infin. .times. .times. (
- 1 ) m m .times. sin .times. { m .times. .times. .pi. .times.
.times. d } .times. cos .times. { m .times. .times. .omega. .times.
.times. x } ##EQU1## where: [0083] 2c: signal width [0084] 2L:
period of the square wave=sum of the length of the work interval
(=2c) and the pause interval
[0085] Retaining only the difference terms in a product of two
series (i.e., the Fourier expansion of the array of emissive
lighting elements 110 and the Fourier expansion of lens array 200)
results in: [ 2 .pi. 2 .times. m = 1 .infin. .times. .times. q = 1
.infin. .times. .times. ( - 1 ) m + q mq .times. sin .times. { q
.times. .times. .pi. .times. .times. d 0 } .times. sin .times. { m
.times. .times. .pi. .times. .times. d } .times. cos .times.
.times. .phi.cos .times. x .times. .times. .pi. PP .times. { q - m
.function. ( LLP ) } ] + [ 2 .pi. 2 .times. m = 1 .infin. .times.
.times. q = 1 .infin. .times. .times. ( - 1 ) m + q mq .times. sin
.times. { q .times. .times. .pi. .times. .times. d 0 } .times. sin
.times. { m .times. .times. .pi. .times. .times. d } .times. sin
.times. .times. .phi. .times. .times. sin .times. .times. x .times.
.times. .pi. PP .times. { q - m .function. ( LLP ) } ] ##EQU2##
where: [0086] LLP: number of lenses 340 per pixel interval, PLED=PP
(mm per pixel interval=pixel pitch)*LLM number of lenses 340 per
unit length)
[0087] Integer differences will lead to low beat frequency, whereas
half-integer factors will lead to the highest beat frequency.
Therefore, the relationship between the pitch of the array of
emissive lighting elements 110 and lens array 200 is chosen to be:
P.sub.LED=(m+0.5)*P.sub.lens [0088] where m is an integer, and
m.gtoreq.1
[0089] There is not a unique solution, as m can take on several
values while balancing between minimizing the size of lenses 340,
in order to reduce Moire effects, and maximizing the size of lenses
340, in order to improve the ease of fabrication.
[0090] A two-dimensional image will result when the focal lengths
of lenses 340 in lens array 200 are the same in both the X axis and
the Y axis directions, whereas a three-dimensional image will
result when the focal lengths are different in the X axis and the Y
axis directions.
[0091] The desired magnification of a virtual image is known and
can be described by (when the two-dimensional problem is reduced to
a one-dimensional problem, and it is assumed that lens array 200 is
immersed in air): M = D - f .times. .times. cos .times. .times.
.THETA. f .times. .times. cos .times. .times. .THETA. = D f .times.
.times. cos .times. .times. .THETA. - 1 ##EQU3## where: [0092] D:
distance between the array of emissive lighting elements 110 and
lens array 200 [0093] f: focal length of lenses 340 [0094] .THETA.:
angle of observation off the normal
[0095] The distance, D, between the array of emissive lighting
elements 110 and lens array 200 can also be determined by the
thickness of lens array 200, D.sub.lens array, and the distance
D.sub.LED-lens one wants between lens array 200 and the array of
emissive lighting elements 110 by the following relationship:
D=D.sub.LED-lens-D.sub.lens.sub.--.sub.array where: [0096] D:
distance between the array of emissive lighting elements 110 and
the surface of lens array 200 nearest the array of emissive
lighting elements 110, measured along optical axis 810 of lenses
340 in lens array 200 [0097] D.sub.lens array: thickness of lens
array 200, i.e. distance between the surface of lens 340 nearest
the array of emissive lighting elements 110 and the surface of lens
340 furthest from the array of emissive lighting elements 110,
measured along optical axis 810 of lens 340 [0098] D.sub.LED-lens:
distance between the array of emissive lighting elements 110 and
the surface of lens 340 furthest from the array of emissive
lighting elements 110, measured along optical axis 810 of lenses
340 in lens array 200
[0099] Knowing the focal length of lenses 340, the required radius
of curvature of lenses 340 can be determined from the following
relationship, assuming the thickness of lenses 340 is disregarded:
n 1 f 1 = n 2 f 2 = ( n lens - n 1 ) R 1 - ( n lens - n 2 ) R 2
##EQU4## where: [0100] n.sub.lens: index of refraction of lenses
340 [0101] n.sub.1: refractive index of the object medium, i.e. the
medium between emissive lighting elements 110 and lenses 340. The
object medium can be air, but it can also be some kind of optical
adhesive. [0102] n.sub.2: refractive index of the image medium. The
image medium will usually be air. [0103] R.sub.1: radius of
curvature of the front of lenses 340 [0104] R.sub.2: radius of
curvature of the back of lenses 340 [0105] f.sub.1: object
effective focal length of the lenses 340 [0106] f.sub.2: image
effective focal length of the lenses 340
[0107] Although the above mathematical equations describe a
two-dimensional space, similar relationships exist describing the
three-dimensional space.
[0108] FIG. 9 illustrates examples of Fresnel lenses 900. The
substrate shape is a flat rectangular lens 910 (if cylindrical) or
a flat disk lens 920 (if radial). One face of the substrate is
formed of radial or rectangular facets, which define the profile of
Fresnel lens 900, which yields optical power. The profile is
constructed of radially flat facets (or a series of flat faces if
sub-segments are used) (not shown). Fresnel lenses 900 can be used
instead of spherical lenses and possess the advantage of being
thinner and lighter. However, the complex surface structure can
lead to imperfections in the virtual image. A Fresnel lens array
consists of an array of such Fresnel lenses 900.
[0109] One-to-one lighting system with front optics 400 can be
designed such that each lens 340 of lens array 200 or each Fresnel
lens 900 of an array of Fresnel lenses 900 is matched one-to-one
with emissive lighting elements 110. Therefore, the pitch of lens
array 200 is equal to the pitch of the array of emissive lighting
elements 110, or P.sub.LED=P.sub.lens. By the user's choosing the
focal length of lenses 340 and positioning lens array 200
appropriately, the viewing angle of emissive lighting elements 110
can be altered to a desired angle. The viewing cone is determined
by the object and image distances. The relationship between the
object distance, the image distance and the focal length is given
by: 1 s 2 = 1 f + 1 s 1 ##EQU5## where: [0110] s.sub.2: image
distance [0111] s.sub.1: object distance [0112] f: focal length of
lens 340 (it is assumed that lens array 200 is immersed in air,
i.e. f.sub.1=f.sub.2=f)
[0113] FIG. 10 illustrates an example of a gradient-index lens
(GRIN) 1000. GRIN lens 1000 utilizes a refractive index gradient.
The index of refraction is highest in the center of the lens and
decreases as distance from the axis increases. GRIN lens 1000
focuses light through a precisely controlled radial variation of
the lens material's index of refraction, from the optical axis to
the edge of the lens. GRIN lens 1000 offers an alternative to the
often-painstaking craft of polishing curvatures onto glass lenses.
Because the index of refraction is gradually varied within the lens
material, light rays can be smoothly and continually redirected
towards a point of focus. The internal structure of this index
gradient can dramatically reduce the need for tightly controlled
surface curvatures and results in simple, compact lens geometry. A
GRIN lens array is formed of an array of GRIN lenses 1000.
[0114] In many applications, the ability to change the optimum
viewing angle of emissive lighting elements 110 or alter the
viewing cone of emissive lighting elements 110 is an important
feature. In order to achieve these features, one-to-one lighting
system with front optics 400, is designed such that one lens 340
per emissive lighting element 110 is used. Therefore, the pitch of
lens array 200 is equal to the pitch of the array of emissive
lighting elements 110, or P.sub.LED=P.sub.lens. The distance, D,
between lens array 200 and the array of emissive lighting elements
110 is made as small as possible. This ensures that light rays from
emissive lighting elements 110 pass only through the lens 340 for
which they have been designed rather than through another lens in
lens array 200 that may be adjacent. The focal length of lens 340
is chosen in such a way as to create the desired viewing cone.
[0115] If emissive lighting element 110 is an organic LED (OLED),
an array of GRIN lenses 1000 may be preferred. Because of the
changing refractive index, the desired optical effects can be
created inside GRIN lens 1000. GRIN lens 1000 does not require an
air gap between it and emissive lighting elements 110, nor between
GRIN lens 1000 and the viewer side of the display, which is
generally required with other types of lenses, such as Fresnel lens
800. The air gap provides the necessary refractive index change
that other types of lenses require to produce the desired optical
effect.
[0116] FIG. 11A illustrates a single light pipe 1100.
[0117] FIG. 11B illustrates a light pipe array 1120, which is made
up of an array of light pipes 1100. Light pipe array 1120 can be
used to change the fill factor or the viewing angle of lighting
module 100. In combination with a black matrix 410, light pipe
array 1120 can also be used to increase the contrast of a
display.
[0118] In one embodiment, one-to-one lighting system with front
optics 400 is designed such that there is one light pipe 1100 for
each emissive lighting element 110. Therefore, the pitch of light
pipe array 1120 is equal to the pitch of the array of emissive
lighting elements 110. By the user's choosing an appropriate
entrance and exit aperture and length of light pipe 1100, the
viewing angle of emissive lighting element 110 can be altered to a
desired angle.
[0119] FIG. 12A illustrates an example of a surface relief
diffractive optical element 1200. One example of the surface of
such an optical element is a binary surface relief diffractive
optical element 1210.
[0120] FIG. 12B illustrates a second example of surface relief
diffractive optical element 1200. Another example of the surface of
such an optical element is a multi-layer surface relief diffractive
optical element 1220.
[0121] Diffractive optical elements (DOE) are generalized
diffraction gratings. In contrast to conventional optical systems,
which rely on reflection and refraction, diffractive optical
elements work by diffracting light. The unique property of a
diffractive optical element is that the properties of complex
optical systems can be encoded in a single element. Diffractive
optical elements can perform more than one optical function. For
example, they can perform the combination of one or more of
filtering, beam division, focusing, etc. Broadly speaking the
diffraction process is not affected by the shape of the device.
Although thickness is a design parameter, it is measured in microns
and has minimal effect on form factor. As a result, diffractive
elements are extremely thin and avoid the aperture/weight tradeoffs
that exist in classical optical systems. Their intrinsic thinness
and fundamental diffractive properties also allow for unique and
extreme form factors not achievable with conventional optics.
Diffractive optics can be based on surface relief structures or
alternately thin phase gratings recorded in the bulk medium using
holography. The surface relief diffractive optical element is
created by encoding a relief pattern directly on the surface of the
optical component. This pattern is constructed using miniature
features. These features may be constructed using techniques such
as diamond turning or photolithography. The phase of incoming light
is manipulated according to the thickness of the features and the
index of refraction of the material. The DOEs are characterized by
high efficiency, design flexibility, light weight and small size.
Furthermore, they can be replicated at low cost for mass
production.
[0122] FIG. 13 illustrates an example method 1300 of optically
enhancing a video and/or lighting system by using optical elements
that are placed in front of the lighting source. The method allows
a combination of effects to be created by the combination of
optical elements. The video and/or lighting system can be tailored
to different operating environments, for example, indoors or
outdoors. Method 1300 includes the steps of:
Step 1305: Determining Environment of Use
[0123] In this step, the environment in which the video and/or
lighting system is used is determined. How the system is viewed is
also determined. For example, a specific video or lighting system
may be used indoors or outdoors, may be viewed from below or from
several angles, or may be used in bright sunlight or at night.
Method 1300 proceeds to step 1310.
Step 1310: Determining Desired Video and/or Lighting Effect
[0124] In this step, use of a specific video or lighting effect is
determined. The desired effect is a function of the application of
the video or lighting display, for example, message notification or
entertainment. The desired effect is also a function of the
environment in which lighting module 100 will be used, for example,
indoors or outdoors. Video and/or lighting effects may include, but
are not limited to, two-dimensional magnification,
three-dimensional image, enhanced contrast, adjusted brightness,
diffusion, color change, altered viewing angle, altered viewing
cone, and modified emission profile. Method 1300 proceeds to step
1315.
Step 1315: Choosing Appropriate Optical Element to Create
Effect
[0125] In this step, an optical element is chosen that will best
produce the desired video or lighting effect. Factored into the
decision is the use of the application, environment, and size, as
well as cost and design considerations. Optical element arrays may
include, but are not limited to, spherical or rectangular lenses,
Fresnel lenses 900, GRIN lenses 1000, light pipes 1100, thin films
720, and diffractive optical elements 1200. Method 1300 proceeds to
step 1320.
Step 1320: Determining Characteristics of Optical Element Array
[0126] In this step, characteristics of the optical element array
are determined that will best produce the desired video and/or
lighting effect appropriate to the application, environment, and
intended use of the lighting system. Parameters include, but are
not limited to, index of refraction for lenses 340, focal length
for lenses 340, pitch of lens array 200, distance between lens
array 200 and the array of emissive lighting elements 110, color of
thin film 720, contrast-enhancing elements, such as black matrices
510 or shade array 330, emission profile of emissive lighting
elements 110, preferred viewing angle, size, and cost. For example,
if compact size is an important characteristic of a video and/or
lighting system, an optical element array that is thin and small
may be used. Alternatively, if cost is a more important
consideration than size, larger, cheaper optical element arrays may
be used to create the desired effects. Method 1300 proceeds to step
1325.
Step 1325: Determining Mechanism for Attaching Optical Element
Array to Lighting Module
[0127] In this step, how the optical element array is attached to,
or placed in front of, lighting module 100 is determined. For
example, the video and/or lighting system and the optical element
array may be the same size as the display and attached by clicking
system 300, a fixing mechanism with bolts, or even by placing the
optical element array in front of the video and/or lighting system
at a fixed distance, without its making contact with the video
and/or lighting system. In another embodiment, if the video and/or
lighting system is to be used in various applications, an optical
element array of the same size as each lighting module 100 may be
used and attached to each lighting module 100 by clicking system
300 or by affixing the optical element array to lighting module 100
by means of an optical adhesive. An optical adhesive has the
advantage of improving optical performance by limiting light loss,
but its use does make it more difficult to easily construct and
teardown temporary video and/or lighting display systems. Method
1300 proceeds to step 1330.
Step 1330: Another Video and/or Lighting Effect?
[0128] In this decision step, the user determines whether a
combination of multiple video or lighting effects is desired. For
some applications and environments, a combination of effects is
useful, for example, for adding color while increasing contrast or
for diffusing light while changing the viewing cone. A combination
of effects can be created by use of a combination of optical
elements; for example, thin film 720 can be placed in front of
lenses 340. If an additional video and/or lighting effect is
desired, method 1300 returns to step 1310. If no additional video
and/or lighting effects are desired, method 1300 ends.
[0129] The invention is by no means limited to the above described
embodiments and method given as an example and represented in the
accompanying drawings; on the contrary, such a system and method
for optically enhancing a video and/or light elements.
* * * * *