U.S. patent application number 12/236022 was filed with the patent office on 2009-05-21 for light guide member, lighting apparatus using the light guide member, and method of fabricating the light guide member.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Hong-seok LEE, Joo-hyung LEE, Hoon SONG, Jun-bo YOON.
Application Number | 20090129119 12/236022 |
Document ID | / |
Family ID | 40641771 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090129119 |
Kind Code |
A1 |
LEE; Hong-seok ; et
al. |
May 21, 2009 |
LIGHT GUIDE MEMBER, LIGHTING APPARATUS USING THE LIGHT GUIDE
MEMBER, AND METHOD OF FABRICATING THE LIGHT GUIDE MEMBER
Abstract
Provided are a light guide member, a lighting apparatus
including the light guide member, and a method of fabricating the
light guide member. The light guide member comprises: a body, which
is formed as a transparent plate, including a first surface and a
second surface facing the first surface; and a plurality of dimple
type optical controllers formed beneath at least one of the first
surface and the second surface and having reflective surfaces that
reflect light proceeding between the first and second surfaces of
the body toward at least one of the first and second surfaces.
Inventors: |
LEE; Hong-seok;
(Seongnam-si, KR) ; SONG; Hoon; (Seoul, KR)
; YOON; Jun-bo; (Daejeon, KR) ; LEE;
Joo-hyung; (Daejeon, KR) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
40641771 |
Appl. No.: |
12/236022 |
Filed: |
September 23, 2008 |
Current U.S.
Class: |
362/619 ;
264/1.24 |
Current CPC
Class: |
B29C 35/0894 20130101;
B29D 11/00663 20130101; G02B 6/0065 20130101; B29C 33/424 20130101;
G02B 6/0036 20130101; B29C 33/3842 20130101; B29C 2035/0827
20130101; B29K 2083/00 20130101; B29C 37/0053 20130101; G02B 6/0055
20130101 |
Class at
Publication: |
362/619 ;
264/1.24 |
International
Class: |
F21V 8/00 20060101
F21V008/00; B29D 11/00 20060101 B29D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2007 |
KR |
10-2007-0117357 |
Claims
1. A light guide member comprising: a body, which is formed as a
transparent plate, including a first surface and a second surface
facing the first surface; and a plurality of dimple type optical
controllers formed beneath at least one of the first surface and
the second surface and having reflective surfaces that reflect
light proceeding between the first and second surfaces of the body
toward at least one of the first and the second surfaces.
2. The light guide member of claim 1, wherein one of the plurality
of dimple type optical controllers comprises a cavity formed as a
depression in the first surface, and the cavity includes a
reflective surface and a bottom surface surrounded by the
reflective surface.
3. The light guide member of claim 2, wherein the cavity is formed
as a truncated conical shape or a truncated pyramid shape.
4. The light guide member of claim 1, wherein the body has an side
facing light sources that supply light, and the reflective surface
of the one of the plurality of dimple type optical controllers
becomes larger as the optical controllers are further apart from
the side.
5. The light guide member of claim 1, wherein the body comprises
side facing light sources that supply light, and the cavity of the
one of the plurality of dimple-type optical controllers has an
asymmetrical structure, which extends in a direction perpendicular
to a propagating direction of the light.
6. The light guide member of claim 2, wherein the cavity comprises
a bottom surface that is parallel with at least one of the first
surface and the second surface of the body.
7. The light guide member of claim 4, wherein a length of the
cavity of the one of the plurality of dimple-type of the optical
controllers is proportional to the distance of the one of the
plurality of dimple-type optical controllers from the side.
8. The light guide member of claim 1, wherein the light guide
member is formed of an elastic material.
9. The light guide member of claim 8, wherein the elastic material
comprises polydimethylsiloxane.
10. A lighting apparatus comprising: a body, which is formed as a
transparent plate, having a first surface and a second surface
facing the first surface; a plurality of dimple type optical
controllers formed beneath at least one of the first surface and
the second surface and having reflective surfaces that reflect
light proceeding between the first and second surfaces of the body
toward at least one of the first and the second surfaces; and light
sources disposed on a first side of the body which irradiate the
light between the first surface and the second surface.
11. The lighting apparatus of claim 10, further comprising: a
reflective surface disposed on a second side of the body, facing
the light sources.
12. The lighting apparatus of claim 10, wherein one of the
plurality of dimple type optical controllers is a cavity formed as
a depression in the first surface, and the cavity comprises a
reflective surface and a bottom surface surrounded by the
reflective surface.
13. The lighting apparatus of claim 12, wherein the cavity of the
one of the plurality of dimple type optical controllers is formed
as a truncated conical shape or a truncated pyramid shape.
14. The lighting apparatus of claim 10, wherein the body comprises
an side facing the light sources that supply light, and the
reflective surface of the one of the plurality of dimple type
optical controllers becomes larger as the optical controllers are
further apart from the side.
15. The lighting apparatus of claim 10, wherein the body comprises
an side facing light sources that supply light, and the cavity of
the one of the plurality of dimple type optical controllers
comprises an asymmetrical structure, which extends in a direction
perpendicular to a propagating direction of the light.
16. The lighting apparatus of claim 10, wherein the cavity
comprises a bottom surface that is parallel with at least one of
the first surface and the second surface of the body.
17. The lighting apparatus of claim 14, wherein a length of the
cavity of the one of the plurality of dimple type optical
controllers is increased, as the optical controllers are further
apart from the side.
18. The lighting apparatus of claim 10, wherein the light guide
member is formed of an elastic material.
19. The lighting apparatus of claim 18, wherein the elastic
material comprises polydimethylsiloxane.
20. A method of fabricating a light guide member, the method
comprising: forming a plurality of protrusion molds on a template
having a flat surface, each of the plurality of protrusion molds
including a top surface that is wider than a bottom and a side
surface under the top surface and inclined toward the top surface;
forming a transparent half-processed light guide member having a
cross-section corresponding to the plurality of protrusion molds by
applying a transparent material on the template on which the
plurality of protrusion molds are formed; and separating the
transparent half-processed light guide member from the template and
the plurality of protrusion molds so as to form the light guide
member, which includes a first surface, a second surface facing the
first surface, and a plurality of dimple type optical controllers,
corresponding to the protrusion molds, in the first surface,
wherein each of the plurality of dimple type optical controllers
includes a reflective surface corresponding to the inclined side
surface of each of the plurality of protrusion molds.
21. The method of claim 20, wherein the forming of the plurality of
protrusion molds comprises: forming a light blocking mask, having
openings corresponding to the plurality of protrusion molds, on the
template; forming a photosensitive layer for forming the plurality
of protrusion molds on the template to cover the light blocking
mask; irradiating light to the light blocking mask to form exposure
regions corresponding to the shapes of the plurality of protrusion
molds in the photosensitive layer; and developing the
photosensitive layer to obtain the plurality of protrusion molds
from the exposure regions.
22. The method of claim 21, wherein the photosensitive layer is
exposed to diffused light that is incident to a bottom surface of
the template.
23. The method of claim 21, wherein the photosensitive layer is
exposed to parallel light that is incident to the bottom surface of
the template in a direction inclined with respect to the bottom
surface of the template.
24. The method of claim 20, wherein the light guide member is
formed of polydimethylsiloxane (PDMS).
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims priority to Korean Patent
Application No. 10-2007-0117357, filed on Nov. 16, 2007, and all
the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of which are incorporated herein by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Apparatuses and methods consistent with the present
invention relate to a light guide plate, a lighting apparatus using
the light guide plate, and a method of fabricating the light guide
plate, and more particularly, to a light guide plate used in a
backlight or a front light that is used as a lighting apparatus for
displays.
[0004] 2. Description of the Related Art
[0005] In general, backlight apparatuses illuminate flat panel
display apparatuses such as liquid crystal display (LCD)
apparatuses, and can be classified into direct type backlight
apparatuses and light guide type backlight apparatuses according to
a location of a light source. In addition, the light guide type
backlight apparatuses are classified into flat type backlights and
wedge type backlights.
[0006] In direct type backlight apparatuses, a light source is
located right under a light-exiting surface so as to perform a
surface-emission, and thus, a plurality of light sources can be
arranged to improve a brightness and a light emitting surface can
be increased. However, power consumption is increased, and it is
difficult to diffuse the light sufficiently when the display is
thinned. Then, a shape of a lamp in the light source is projected
through a display screen, and thus, the uniformity of the
brightness is degraded.
[0007] A light guide type backlight apparatus has a structure, in
which light is incident from an edge of the light guide plate and
is discharged through a light-exiting surface of the light guide
plate, which is perpendicular to the edge of the light guide plate.
Since the light source is disposed on the edge or a side surface of
the light guide plate, a lateral length of the light guide plate
limits the number of light sources. In addition, although it is
easy to make the light guide type backlight apparatus thin, a
structure for evenly distributing the brightness throughout the
light emitting surface is more complicated than that of the direct
type backlight apparatus.
[0008] A flat type backlight apparatus is used in monitors or cases
requiring a high brightness. Light sources can be fixed on side
edges or four corners of the light guide plate. In addition, in
order to improve the brightness using a plurality of light sources,
a thickness of the light guide plate must be constant.
[0009] A wedge type backlight apparatus is used when it is
difficult to use a plurality of light sources because the power
consumption is restricted, for example, in laptop computers. The
wedge type backlight apparatus can be formed to have a structure,
in which a surface, to which the light is incident, has a large
area and the other surface has a small area, so as to reduce the
weight of the wedge type backlight apparatus.
[0010] Line sources or point sources can be used as the light
sources used in the light guide plate type backlight apparatus.
Cold cathode fluorescent lamps (CCFL), in which electrodes are
formed on both end portions of a tube, can be used as the line
sources, and light emitting diodes (LEDs) can be used as the point
sources. CCFL can emit high-intensity white light, obtain the light
having high brightness and high uniformity, and can be designed to
each have a large area. However, CCFL are driven by radio frequency
alternating current (AC) signals, and operate within a small
temperature range. LEDs emit light having lower brightness and
lower uniformity than that of CCFL, however, LEDs are driven by a
direct current (DC) signal within a large temperature range and
have a long lifespan. In addition, LEDs may be formed to be
thin.
[0011] On the other hand, a front light apparatus is located on a
front portion of a display, and can be applied to, for example, a
flexible display, which is referred to as e-paper. In the front
light apparatus applied to the flexible display, the light source
is disposed on edges of the light guide plate, and the front light
apparatus is installed on the front portion of the flexible display
to provide the flexible display with illumination light. The light
guide plate used in the front light apparatus must transmit the
display light reflected from the flexible display while
illuminating the light from the edges to the flexible display,
which is located on the rear portion of the front light apparatus.
Therefore, the light guide plate used in the front light apparatus
must transmit the display light reflected from the display, as well
as provide the display with the light from the light source
efficiently.
SUMMARY OF THE INVENTION
[0012] The present invention provides a light guide plate that can
be commonly applied to both a backlight apparatus and a front light
apparatus, a lighting apparatus using the light guide plate, and a
method of fabricating the light guide plate.
[0013] According to an aspect of the present invention, there is
provided a light guide member including: a body, which is formed as
a transparent plate, including a first surface and a second surface
facing the first surface; and a plurality of dimple type optical
controllers formed beneath at least one of the first surface and
the second surface and having reflective surfaces that reflect
light proceeding between the first and second surfaces of the body
toward at least one of the first and second surfaces.
[0014] According to another aspect of the present invention, there
is provided a lighting apparatus including: a body, which is formed
as a transparent plate, having a first surface and a second surface
facing the first surface; a plurality of dimple type optical
controllers formed beneath at least one of the first surface and
the second surface and having reflective surfaces that reflect
light proceeding between the first and second surfaces of the body
toward at least one of the first and second surfaces; and light
sources disposed on an edge of the body for irradiating the light
between the first surface and the second surface.
[0015] The lighting apparatus may further include: a reflective
surface disposed on the other edge of the body to face the light
source.
[0016] The dimple type optical controllers are commonly formed on
the first and second surfaces of the body, and the optical
controllers on each of the surfaces reflect the light toward the
opposite surface.
[0017] The reflective surface of the optical controller is formed
to be commonly inclined with respect to the first and second
surfaces of the body to reflect the light proceeding in the body
toward the surface facing the surface, on which the corresponding
optical controller is formed.
[0018] The optical controller includes at least two reflective
surfaces facing each other, and there is a cavity, having an
opening that is narrower than the bottom surface thereof, between
the reflective surfaces facing each other.
[0019] The reflective surface can be plane or curved, and the
cavity can include the bottom surface that is in parallel with the
first and second surfaces of the body or curved as a spherical or
an aspherical shape.
[0020] The size of the optical controller may increase as the
optical controller is apart from the light source. In addition, the
optical controller may have an asymmetric structure, that is, a
length of the direction where the light is incident is shorter than
the direction perpendicular to the light incident direction, and
the length in the direction perpendicular to the light incident
direction may be increased.
[0021] The optical controllers can be arranged as islands or
stripes on the body, and the density of the optical controllers can
increase linearly or non-linearly as the optical controllers are
apart from the light source.
[0022] Each of the optical controllers formed as stripes is
disposed to extend in a direction facing the light source.
[0023] The optical controllers of stripe shapes and the optical
controllers of the island shapes are mixed on the body.
[0024] According to another aspect of the present invention, there
is provided a method of fabricating a light guide member, the
method including: forming a plurality of protrusion molds on a
template having a flat surface, each of the protrusion molds
including a top surface that is wider than a bottom and a side
surface under the top surface and inclined toward the top surface;
forming a transparent half-processed light guide member having a
cross-section corresponding to the protrusion molds by applying a
transparent material on the template on which the protrusion molds
are formed; and separating the half-processed light guide member
from the template and the protrusion molds so as to form the light
guide member, which includes a first surface, a second surface
facing the first surface, and a plurality of dimple type optical
controllers, corresponding to the protrusion molds, in the first
surface, wherein each of the optical controllers includes a
reflective surface corresponding to the inclined side surface of
each of the protrusion molds.
[0025] The forming of the protrusion molds may include: forming a
light blocking mask, having openings corresponding to the
protrusion molds, on the template; forming a photosensitive layer
for forming the protrusion molds on the template to cover the light
blocking mask; irradiating light to the light blocking mask to form
exposure regions corresponding to the shapes of the protrusion
molds in the photosensitive layer; and developing the
photosensitive layer to obtain the protrusion molds from the
exposure regions.
[0026] The light guide member may be formed of an elastic material,
in particular, the elastic material may be
polydimethylsiloxane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The above and other features of the present invention will
become more apparent by describing in detail exemplary embodiments
thereof with reference to the attached drawings in which:
[0028] FIG. 1 is a schematic perspective view of a lighting
apparatus having a light guide member, according to an embodiment
of the present invention;
[0029] FIG. 2 is a cross-sectional view of an optical controller in
the light guide member, according to the embodiment of the present
invention;
[0030] FIGS. 3A through 3E are perspective views showing structures
of optical controllers according to embodiments of the present
invention;
[0031] FIG. 4 is a schematic cross-sectional view of the lighting
apparatus 100 to illustrate a light proceeding structure of the
optical controllers that each have reflective surfaces;
[0032] FIG. 5 is a plan view showing changes in the sizes of light
controllers and arrangements of the light controllers in the light
guide member according to another embodiment of the present
invention;
[0033] FIG. 6 is a cross-sectional view of a lighting apparatus
according to another embodiment of the present invention; and
[0034] FIGS. 7A through 7J are cross-sectional views illustrating a
method of fabricating the light guide member, according to an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The invention is described more fully hereinafter with
reference to the accompanying drawings, in which exemplary
embodiments of the invention are shown. This should not be
construed as limiting the claims to the exemplary embodiments
shown. Rather, these embodiments are provided to convey the scope
of the invention to those skilled in the art. In the drawings, the
size and relative sizes of elements and regions may be exaggerated
for clarity.
[0036] It will be understood that when an element or layer is
referred to as being "on", "disposed on", "disposed", or "between"
another element or layer, it can be directly on, disposed on,
disposed, or between the other element or layer, or intervening
elements or layers can be present.
[0037] The terms "first," "second," and the like, "primary,"
"secondary," and the like, as used herein do not denote any order,
quantity, or importance, but rather are used to distinguish one
element, region, component, layer, or section from another. The
terms "front", "back", "bottom", and/or "top" are used herein,
unless otherwise noted, merely for convenience of description, and
are not limited to any one position or spatial orientation.
[0038] The terms "a" and "an" do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced item. The suffix "(s)" as used herein is intended to
include both the singular and the plural of the term that it
modifies, thereby comprising one or more of that term (e.g., the
layer(s) includes one or more layers).
[0039] Reference throughout the specification to "one embodiment",
"another embodiment", "an embodiment", and so forth, means that a
particular element (e.g., feature, structure, and/or
characteristic) described in connection with the embodiment is
included in at least one embodiment described herein, and may or
may not be present in other embodiments. In addition, it is to be
understood that the described elements may be combined in any
suitable manner in the various exemplary embodiments.
[0040] Unless defined otherwise, technical and scientific terms
used herein have the same meaning as is commonly understood by one
of skill in the art to which this invention belongs. FIG. 1 is a
partially cut perspective view showing a schematic structure of a
lighting apparatus 100 including an integral type light guide
member, according to an embodiment of the present invention.
[0041] Referring to FIG. 1, the lighting apparatus 100 according to
the present embodiment includes a transparent plate-shaped body 101
having a first surface 101a and a second surface 101b facing the
first surface 101a. Light sources 110 are disposed close to a side
of the body 101, and a reflective layer 120 is selectively disposed
on the opposite side of the body 101. The light sources 110 are
each an apparatus for injecting light into the body 101, and the
reflective layer 120 reflects the light incident to the side of the
body 101 into the body 101 to improve a light-use efficiency.
[0042] On the other hand, dimple type optical controllers 102 are
formed in the first surface 101a of the body 101. The optical
controllers 102 are each a cavity 102c formed as a well extending
downward from the first surface 101a, and are distributed
completely throughout the body 101. The optical controllers 102 may
be evenly distributed, or locally distributed. As shown in FIG. 2,
the dimple type optical controllers 102, that is, the optical
controllers 102 each having a recessed shape, each include the
cavity 102c formed as a depression in the first surface 101a of the
body 101, and reflective surfaces 102a and 102b that respectively
form a side surface and a bottom of the cavity 102c and reflect the
light inside the body 101. The reflective surfaces 102a and 102b
reflect the light that is in the body 101 according to a difference
between the refractive indexes of a medium of the body 101 and a
medium of the cavity 102c, and in particular, reflect the light
proceeding between the first surface 101a and the second surface
101b toward at least one of the first and second surfaces 101a and
101b. The reflective surface 102a, forming the side surface of the
cavity 102c, is inclined with respect to the bottom surface of the
cavity 102c, and accordingly, the cavity 102c has a narrow opening
and the reflective surface 102b is wider than the opening.
[0043] According to the present embodiment of the present
invention, the body 101 is formed of polydimethylsiloxane (PDMS) to
a thickness of 400 to 600 .mu.m. The opening and bottom of the
cavity 102c have diameters of 12 to 13 .mu.m and 25 to 35 .mu.m,
respectively. In addition, a depth of the cavity 102c is 10 to 15
.mu.m, and a pitch between the cavities 102c is about 50 to 70
.mu.m.
[0044] The reflective surface 102b can be disposed in parallel with
the first and second surfaces 101a and 101b. In addition, the
reflective surfaces 102a and 102b can be flat or curved, or mixed.
On the other hand, when the cavity 102c has a curved side surface,
for example, when the cavity 102c has a truncated conical side
surface, the side surface of the cavity 102c is continuously
formed. In addition, the side surface of the cavity 102c can be
formed as a three-dimensional curved surface; for example, the
cavity 102c can be formed as a barrel having a bulged intermediate
portion.
[0045] FIGS. 3A through 3E show various examples of optical
controllers according to embodiments of the present invention. FIG.
3A shows an optical controller 102(a) having a truncated conical
cavity. FIG. 3B shows an optical controller 102(b) having a barrel
type cavity that includes a narrow opening and a wide bottom
surface. FIG. 3C shows an optical controller 102(c) having a cavity
formed as a truncated quadrangular pyramid. Although FIG. 3C shows
the quadrangular pyramid type cavity, the optical controller 102(c)
may have a truncated pyramid type cavity for which an example is
the truncated quadrangular pyramid type cavity. FIG. 3D shows an
optical controller 102(d) having a slot type cavity that is
linearly elongated. FIG. 3E shows an optical controller 102(e)
having a slot type cavity that is curved. As described above,
various types of optical controllers can be obtained. In addition,
the technical scope of the present invention is not limited by the
shape of the optical controller.
[0046] FIG. 4 is a schematic cross-sectional view of the lighting
apparatus 100 to illustrate a light guide structure of the optical
controllers 102 each having the reflective surfaces 102a and
102b.
[0047] Referring to FIG. 4, the light emitted from the light source
110 such as an LED is incident (or introduced) to the body 101,
proceeds in the body 101, and then, is totally reflected by the
reflective surfaces 102a and 102b of the optical controllers 102 to
exit the plate-shaped body 101 in a direction 250. Here, the light
that is not discharged out of the body 101 is reflected by the
reflective layer 120 that is located on an opposite side of the
light source 110 toward the inside of the body 101, and then, the
light reflected by the optical controller 102 is discharged out of
the plate-shaped body 101 through the first surface 101 a. Through
the above internal reflecting structure, some of the light may be
discharged through the second surface 101b. A light emission
direction of the light injected into the body 101 may vary
depending on the requirements of the lighting apparatus 100, for
example, when an additional reflective layer (not shown) is formed
on the second surface 101b of the plate-shaped body 101, in a
backlight apparatus, the light is only emitted through the first
surface 101a. However, in a front light apparatus, display light
from the display must transmit through the front light apparatus,
and the light emitted from the light source 110 is output to the
display, for example, through the first surface 101a, and the light
incident to the first surface 101a from the display must be output
through the second surface 101b. The optical controllers 102 can be
arranged according to the required design of the light
apparatus.
[0048] A plurality of optical controllers 102 can be arranged in
the light guide member 101, and in the present embodiment, the
further the optical controllers 102 are located away from the light
source 110, the concentration of the optical controllers 102
becomes higher. To do this, the distances or pitches between the
optical controllers 102 can be linearly or non-linearly reduced as
the optical controllers 102 are disposed further away from the
light source 110. In addition, when the optical controllers 102 are
distributed to be set apart from each other, the sizes of the
optical controllers 102 can be differentiated so as to change the
sizes of the reflective surfaces 102a and 102b, for example, so as
to increase the area of the reflective surfaces 102a and 102b as
the optical controllers 101 are further away from the light source
110.
[0049] FIG. 5 is a plan view of a lighting apparatus 100 having the
body 101, on which the sizes and concentration of the optical
controllers 102 having various shapes are different according to
the distance of the optical controllers 102 from the light sources
110.
[0050] The various types of optical controllers 102(a), 102(c),
102(d), and 102(e) are arranged in the first surface 101a of the
body 101 in the light apparatus 100. The optical controllers
102(a), 102(c), 102(d), and 102(e) are arranged along lines that
are arranged with constant intervals from the light sources 110,
and the concentration of the optical controllers in each of the
lines increases as the lines are further apart from the light
sources 110. The density of each line can be adjusted by changing
the sizes and lengths of the optical controllers 102(a), 102(c),
102(d), and 102(e).
[0051] The LED as a point source, or the CCFL as a line source can
be used as the light sources 110, and the shapes or arrangement of
the optical controllers 102(a), 102(c), 102(d), and 102(e) may be
adjusted according to the type of the light sources 110. The point
source is appropriate for a front light apparatus, in which the
light emission angle is not an important factor, and CCFL is
appropriate for the line source.
[0052] The optical controllers 102 according to the embodiments of
the present invention can be commonly formed in both the first and
second surfaces 101a and 101b of the body 101 as shown in FIG. 6.
At this time, a reflective plate 130 may be formed on the second
surface 101b so that the light proceeding toward the second surface
101b can be reflected to the first surface 101a, and thereby
increasing the light-use efficiency. Therefore, the structure shown
in FIG. 6 can be used as a backlight apparatus in an LCD. In FIG.
6, optical controllers 102 are symmetrically formed in the first
and second surfaces 101a and 101b, however, the optical controllers
102 may be asymmetrically disposed in the first and second surfaces
101a and 101b, and the distribution concentration and the shapes of
the optical controllers 102 in each of the first and second
surfaces 101a and 101b may be changed according to the optical
characteristics of the lighting apparatus 100.
[0053] The light guide member and the lighting apparatus according
to the present invention may not use an additional optical film as
used in conventional backlight systems for LCD devices. That is,
the light guide member having engraved optical controllers, that
is, the dimple type optical controllers, formed using a simple
lithography process is used, and thus, a lighting apparatus that is
thin and light-weight can be formed with low fabrication costs. The
light guide member and the lighting apparatus according to the
present invention can be used as a backlight system in an LCD
device, and can be used as a backlight of flexible LCD devices or a
front light system in next generation flexible displays such as
e-paper. In particular, when the lighting apparatus including the
light guide member according to the present invention is applied as
a front light apparatus, there is no air layer between the display
and the light guide member, and thus, the reflection of external
light can be reduced so as to improve visibility and a contrast
ratio.
[0054] Hereinafter, a method of fabricating the light guide member
according to an embodiment of the present invention will be
described. In the current embodiment, the light guide member having
the optical controllers 102 shown in FIG. 1 is fabricated, however,
a light guide member having the other types of optical controllers
102(a), 102(c), 102(d), and 102(e) also can be fabricated.
[0055] Referring to FIG. 7A, a light blocking material, for
example, a metal layer 302', is formed on a template 301, which is
formed of a transparent material, and then, a photosensitive layer
303' is coated on the metal layer 302'.
[0056] Referring to FIG. 7B, the photosensitive layer 303' is
patterned to form a mask layer 303. The photosensitive layer 303'
is patterned using a photolithography process, and in the present
embodiment, the photosensitive layer 303' is patterned using a
positive photoresist and developed using a wet developer. Portions
that are not covered by the mask layer 303 correspond to the
openings of the cavities 102c.
[0057] Referring to FIG. 7C, the metal layer 302' is patterned by a
general wet or dry etching process using the mask layer 303 so as
to form a light blocking mask layer 302 that is formed of a
metal.
[0058] Referring to FIG. 7D, a photosensitive layer 307', covering
the light blocking mask layer 302, is formed on the template 301.
In the present embodiment, the photosensitive layer 307' is formed
using a negative photoresist.
[0059] Referring to FIG. 7E, light is irradiated to a bottom
surface of the template 301 to form photosensitive regions 307'',
each of which is formed as an inverse prism shape, at the openings
302a of the mask layer 302. To do this, diffused light is supplied
from the bottom surface of the template 301. The diffused light can
be obtained by forming a diffusion unit 308 between the light
source and the template 301. On the other hand, when parallel light
is used instead of the diffused light, as shown in FIG. 7F, the
parallel light is incident to the template 301 in a first
direction, which is inclined with respect to the template 301, to
form first exposure regions 307a. Then, as shown in FIG. 7G, the
parallel light is incident to the template 301 in a second
direction, which is opposite to the first direction, to form second
exposure regions 307b. Therefore, the photosensitive regions 307''
can be obtained.
[0060] Referring to FIG. 7H, the photosensitive layer 307' having
the photosensitive regions 307'' is wet-etched to form protrusion
molds 307. The protrusion molds 307 are obtained from the
photosensitive regions 307'' and are formed to correspond to the
cavities 102c of the light guide member 100.
[0061] Referring to FIG. 71, a material for forming the light guide
member 101 is deposited on the template 301 to cover the protrusion
molds 307 so as to form a half-processed light guide member 308.
According to an embodiment of the present invention, the material
for forming the light guide member is an elastic material, for
example, PDMS. After the PDMS is completely cured, the
half-processed light guide member 308 is separated from the
protrusion molds 307 and the template 301, and post-processes are
performed, then, the light guide member 101 having the dimple type
optical controllers 102 can be obtained.
[0062] In the above description, the protrusion molds 307 are
formed of a photosensitive material, however, the present
embodiment of the present invention is not limited thereto, and
thus, the protrusion molds 307 can be formed of a metal. That is,
when the light guide member 101 is fabricated using a metal master,
the molds formed of the photosensitive material are duplicated, and
after that, inverse shapes of the molds are fabricated using a
plating process. Otherwise, inverse molds are fabricated using a
positive photosensitive layer, and after that, the metal molds can
be fabricated by plating the molds. As described above, since the
light guide member 101 is formed of the elastic material, the
duplication can be performed even when the metal molds are used.
Therefore, the molds are not transformed in the duplication, and
the template can be re-used.
[0063] A light guide member and a lighting apparatus according to
the present invention can be used as backlight systems of LCDs, and
as front light systems of reflective LCDs or flexible displays such
as e-paper.
[0064] While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by one of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the present invention as defined by
the following claims.
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