U.S. patent application number 10/933627 was filed with the patent office on 2005-02-17 for surface light source apparatus, and method and apparatus for manufacturing the same.
This patent application is currently assigned to LS TECH CO., LTD.. Invention is credited to Cho, Soon Cheon, Jo, Chi Un, Kim, Min Ho, Kim, Sang Mook, Park, Deuk Il, Rhew, Choong Yop, Sur, Ok Bin, Zoo, Sung Su.
Application Number | 20050036320 10/933627 |
Document ID | / |
Family ID | 29407541 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050036320 |
Kind Code |
A1 |
Park, Deuk Il ; et
al. |
February 17, 2005 |
Surface light source apparatus, and method and apparatus for
manufacturing the same
Abstract
An apparatus for manufacturing a surface light source apparatus
in which a light guide pattern portion is formed on a light guide
panel includes a pattern design system to which data about a
pattern to be formed on the light guide pattern is input. A control
system is connected to the pattern design system and transmits a
position signal matching a coordinate value of each pattern to be
formed on the light guide panel. A header moving portion
mechanically moves vertically and horizontally according to the
position signal received from the control system. A laser system
outputs a laser beam according to a pulse signal synchronized with
a movement of the header moving portion. A lens portion allows a
laser beam output from the laser system to pass the header moving
portion and to be focused on a scanning surface of the light guide
panel. A warp prevention unit prevents the light guide panel from
warping due to a local heating by the laser beam. An absorption and
scattering prevention unit prevents smoke generated when the light
guide pattern portion is formed on the light guide panel.
Inventors: |
Park, Deuk Il; (Suwon-city,
KR) ; Cho, Soon Cheon; (Bucheon-city, KR) ;
Kim, Sang Mook; (Suwon-city, KR) ; Sur, Ok Bin;
(Ohsan-city, KR) ; Rhew, Choong Yop; (Suwon-city,
KR) ; Kim, Min Ho; (Suwon-city, KR) ; Jo, Chi
Un; (Anyang-city, KR) ; Zoo, Sung Su;
(Pyungtaek-city, KR) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
LS TECH CO., LTD.
Hwasung-city
KR
|
Family ID: |
29407541 |
Appl. No.: |
10/933627 |
Filed: |
September 3, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10933627 |
Sep 3, 2004 |
|
|
|
10419527 |
Apr 21, 2003 |
|
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Current U.S.
Class: |
362/331 |
Current CPC
Class: |
G02B 6/0061 20130101;
G02B 6/0036 20130101; G02B 6/0065 20130101 |
Class at
Publication: |
362/331 |
International
Class: |
F21V 007/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2002 |
KR |
2002-26023 |
May 24, 2002 |
KR |
2002-28919 |
Jan 18, 2003 |
KR |
2003-3466 |
Claims
1-8. (Cancelled).
9. A surface light source apparatus comprising: a light guide panel
to scatter and diffuse light at a uniform brightness in an entire
area and a light guide pattern portion having a plurality of
grooves having an intermittent shape; at least one light source
installed at one side wall of the light guide panel and emitting
light to the light guide panel; and a reflection panel installed at
a lower portion of the light guide panel, wherein the grooves
having an intermittent shape of the light guide pattern portion is
formed by scanning a laser beam output from a laser system via a
mirror header portion onto a scanning surface of the light guide
panel by time control while the mirror header portion horizontally
moves on an X-axis guide rail and the X-axis guide rail vertically
moves with respect to a Y-axis guide rail.
10. The apparatus as claimed in claim 9, wherein the light guide
pattern portion has an discontinuous dotted-line shape parallel to
a direction in which the light source is installed.
11. The apparatus as claimed in claim 9, wherein, in the light
guide pattern portion, the length of the groove gradually increases
as the groove is disposed far from the light source.
12. The apparatus as claimed in claim 9, wherein, in the light
guide pattern portion, a pitch between the grooves gradually
decreases as the groove is disposed 15 far from the light
source.
13. The apparatus as claimed in claim 9, wherein, in the light
guide pattern portion, the length of the groove gradually increases
and a pitch between the grooves gradually decreases, as the groove
is disposed far from the light source.
14. The apparatus as claimed in claim 9, wherein, in the light
guide pattern portion, a width between the grooves gradually
decreases as the groove is disposed far from the light source.
15. The apparatus as claimed in claim 9, wherein, in the light
guide pattern portion, the length of the groove gradually
increases, a pitch between the grooves gradually decreases, and a
width between the grooves gradually decreases, as the groove is
disposed far from the light source.
16-26. (Cancelled).
27. The apparatus as claimed in claim 9, wherein at least one
groove has a cross section defining a saw tooth shape.
28. The apparatus as claimed in claim 27, wherein the saw tooth
shape is generally symmetrical around a centerline generally
perpendicular to a major surface of the light guide panel.
29. The apparatus as claimed in claim 28, wherein the saw tooth
shape forms a plurality of vertices on each side of the
centerline.
30. A surface light source apparatus comprising: a linear light
source defining a linear path, the linear light source adapted to
generate a light generally along the entire linear path; a light
guide panel configured to receive the light and scatter and diffuse
the light at a uniform brightness in an entire area and a light
guide pattern portion having a plurality of grooves having an
intermittent shape; and a reflection panel installed at a lower
portion of the light guide panel, wherein the grooves in the light
guide panel have an intermittent shape causing incident light to be
generally redirected in a direction generally perpendicular to a
major surface of the light guide panel.
31. The apparatus as claimed in claim 30, wherein at least one
groove has a cross section defining a saw tooth shape.
32. The apparatus as claimed in claim 31, wherein the saw tooth
shape is generally symmetrical around a centerline generally
perpendicular to a major surface of the light guide panel.
33. The apparatus as claimed in claim 32, wherein the saw tooth
shape forms a plurality of vertices on each side of the
centerline.
34. A surface light source apparatus comprising: a light guide
panel configured to scatter and diffuse light at a uniform
brightness in an entire area and a light guide pattern portion
having a plurality of grooves having an intermittent shape; at
least one light source installed at one side wall of the light
guide panel and emitting light to the light guide panel; and a
reflection panel installed at a lower portion of the light guide
panel, wherein the grooves having an intermittent shape and a
length, as measured generally parallel to the at least one light
source, the length of the grooves in the light guide panel
gradually increases as a distance from the at least one light
source increases.
35. The apparatus as claimed in claim 34, wherein the at least one
light source is a linear light source defining a linear path, the
linear light source adapted to generate a light generally along the
entire linear path.
Description
BACKGROUND OF THE INVENTION
[0001] This application claims the priorities of Korean Patent
Application No. 2002-26023, Korean Patent Application No.
2002-28919, and Korean Patent Application No. 2003-3466,
respectively filed on 11 May 2002, 24 May 2002, and 18 Jan. 2003,
in the Korean Intellectual Property Office, the disclosures of
which are incorporated herein in their entireties by reference.
[0002] 1. Field of the Invention
[0003] The present invention relates to a surface light source
apparatus, and more particularly, to a surface light source
apparatus for forming a light guide pattern portion by scanning a
laser beam using a head moving portion capable of moving above a
light guide panel in vertical and horizontal directions, a method
of manufacturing the surface light source apparatus, and an
apparatus for manufacturing the surface light source apparatus.
[0004] 2. Description of the Related Art
[0005] In general, a light guide panel is a plate providing a path
through which light scanned from a light source is uniformly
scattered and diffused. The light guide panel is applied to a light
receiving flat display panel such as an LCD device, or a surface
light source apparatus used for an illuminating signboard.
[0006] As a surface light source apparatus, a method of arranging a
cold cathode fluorescent lamp (CCFL) or an LED, and a flat panel
fluorescent lamp method in which a circuit board coated with a
fluorescent material is assembled, are widely used. The CCFL can be
classified into an edge light type using a light guide panel and a
direct light type in which the light sources are arranged on a flat
surface to overlap one another, according to the arrangement of a
light source with respect to a display surface. These surface light
source apparatuses are disclosed in Korean Patent Application Nos.
93-11174, 94-26117, 94-33115, 94-26116, and 2000-44725.
[0007] Referring to FIG. 1, a conventional surface light source
apparatus 10 includes a light guide panel 11, a reflection panel 12
installed under the light guide panel 11, a light source 13
installed on a side wall of the light guide panel 11, and a cover
member 14 covering the light source 13. A CCFL or an LED can be
used as the light source 13.
[0008] A plurality of light guide pattern portions 15 printed using
titanium oxide TiO.sub.2 having a bead shape and ink including
glass or acryl to scatter and diffuse light incident on one surface
of a transparent acryl resin is formed on the light guide panel
11.
[0009] In the surface light source apparatus 10 having the above
structure, light emitted from the light source 13 is incident on
the light guide panel 11. The incident light is guided through the
light guide panel 11 as indicated by an arrow and reflected by the
reflection panel 12 and the light guide pattern portions 15 to have
a relatively uniform intensity of illumination at each portion
thereof.
[0010] However, the light guide pattern portions 15 formed in a
print method has the following problems.
[0011] The processes of manufacturing and printing of ink to form
the light guide pattern portions 15 are very complicated, and part
of printed portions can be removed or smeared is high so that a
defective ratio is very high. Yield of the light guide pattern
portions 15 is about 80 through 90%, which is relatively low. Also,
since the light guide panel 11 on which the light guide pattern
portions 15 are not printed well cannot be reused after the light
guide pattern portions 15 are removed, a manufacturing cost is
increased.
[0012] In particular, since the light guide pattern portions 15
utilize optical reflection of a printed ink object itself, the ink
object unavoidably absorbs light. The light absorption phenomenon
lowers an efficiency of light of the surface light source
apparatus.
[0013] Also, as shown in FIG. 2, a surface S of the light guide
panel 11 is typically regularized to have a very small thickness
deviation t.sub.1 of about .+-.100 .mu.m. Accordingly, a cost of a
raw material of a product is relatively high. If the thickness
deviation is regularized relatively greater, the cost of a raw
material of a product can be lowered. However, when a screen 21
having a predetermined pattern containing ink objects is arranged
on the surface S of the light guide panel 11 and the ink objects
are printed by using a squeegee 22, the amount of coated ink in
each area of the light guide panel 11 differs from one another by
more than 50% due to the thickness deviation t.sub.1 and the size
of each of the light guide pattern portions 15 changes to 50
through 100 .mu.m.
[0014] To solve the above problem, conventionally, a non-print
method is adopted as shown in FIG. 3. As the non-print method,
there is a stamping method using a mold and an injection mold
method.
[0015] Referring to FIG. 3, a surface light source apparatus 30
includes a light guide panel 31, a reflection panel 32 installed
under the light guide panel 31, and a light source 33 installed at
a side wall of the light guide panel 31. A plurality of light guide
pattern portions 34 having a plurality of grooves having conic
shapes are formed on the light guide panel 31 by heating and
pressing the light guide panel 31 using a mold having a protruding
portion on one surface thereof. The shape of the section of the
light guide pattern portion 34 forms a V shape, as shown in FIG.
4.
[0016] In the surface light source apparatus 30 having the above
structure, light emitted from the light source 33 is incident on
the light guide panel 31. When the incident light proceeds in the
light guide panel 31, part of the light is reflected by an inclined
surface of the light guide pattern portion 34.
[0017] However, the light guide pattern portion 34 has the
following problem.
[0018] Since the light guide pattern portion 34 is formed in a heat
and press method using a mold, the management of the process is
very difficult. In particular, since acryl resin which is a
material of the light guide panel 31 is very weak at heat, the
light guide pattern portion 34 having a desired pattern cannot be
accurately made.
[0019] Also, the above method realizes a surface light source
simply by optical reflection by a mirror, which lowers the
diffusiveness of light. As a result, a phenomenon that the shape of
the light guide pattern portion 34 appears strongly, occurs. To
prevent the phenomenon, a diffusion sheet is additionally arranged,
however, the phenomenon is not completely removed.
[0020] Further, as shown in FIG. 5, the light guide panel 31
typically has a thickness deviation t.sub.2 about .+-.100 .mu.n.
When the light guide pattern portion 34 is processed on the light
guide panel 31 using a mold 51 having a processing depth of about
100 .mu.m, a protruding portion 52 formed on the mold 51 can form
the conic grooves at the thickest portion of the light guide panel
31 by heating and pressing the portion to the depth of 100 .mu.m.
However, at the thinnest portion of the light guide panel 31, the
light guide pattern portion 34 is not processed at all.
[0021] Thus, to obtain an optimal light guide efficiency, a
material having a very precise thickness deviation is needed and
more than tens of correction works of the mold 51 should be
repeated. Consequently, the cost for development rises. In
addition, since the manufacturing duration of the mold 51 is
extended, development of a variety of products is made
difficult.
SUMMARY OF THE INVENTION
[0022] To solve the above and other problems, the present invention
provides a surface light source apparatus which forms a light guide
pattern portion on a light guide panel using a laser system capable
of freely moving in vertical and horizontal directions by a
mechanical driving and prevents in advance interfering factors
occurring during scanning of a laser beam, a method of
manufacturing the surface light source apparatus, and an apparatus
for manufacturing the surface light source apparatus.
[0023] Also, the present invention provides a surface light source
apparatus which forms a light guide pattern portion on one surface
of the light guide panel by a laser beam process, and has a
micro-lens portion in each of grooves formed in the light guide
pattern portion so as to improve features of reflection and
scattering of light, a method of manufacturing the surface light
source apparatus, and an apparatus for manufacturing the surface
light source apparatus.
[0024] Also, the present invention provides a surface light source
apparatus which processes a light guide pattern portion having an
intermittent shape on a lower surface of the light guide panel
using a laser beam so as to have light guided in the entire surface
of the light guide panel at a uniform brightness, a method of
manufacturing the surface light source apparatus, and an apparatus
for manufacturing the surface light source apparatus.
[0025] According to an aspect of the present invention, an
apparatus for manufacturing a surface light source apparatus in
which a light guide pattern portion is formed on a light guide
panel, which comprises a pattern design system to which data about
a pattern to be formed on the light guide pattern is input, a
control system connected to the pattern design system and
transmitting a position signal matching a coordinate value of each
pattern to be formed on the light guide panel, a header moving
portion mechanically moving vertically and horizontally according
to the position signal received from the control system, a laser
system outputting a laser beam according to a pulse signal
synchronized with a movement of the header moving portion, a lens
portion allowing a laser beam output from the laser system to pass
the header moving portion and to be focused on a scanning surface
of the light guide panel, a warp prevention unit preventing the
light guide panel from warping due to a local heating by the laser
beam, and an absorption and scattering prevention unit preventing
smoke generated when the light guide pattern portion is formed on
the light guide panel.
[0026] According to another aspect of the present invention, a
surface light source apparatus comprises a light guide panel
processed by a laser beam to scatfer and diffuse light at a uniform
brightness in an entire area and a light guide pattern portion
having a plurality of grooves having an intermittent shape, at
least one light source installed at one side wall of the light
guide panel and emitting light to the light guide panel, and a
reflection panel installed at a lower portion of the light guide
panel, wherein the grooves having an intermittent shape of the
light guide pattern portion is formed by scanning a laser beam
output from a laser system via a mirror header portion onto a
scanning surface of the light guide panel by time control while the
mirror header portion horizontally moves on an X-axis guide rail
and the X-axis guide rail vertically moves with respect to a Y-axis
guide rail.
[0027] According to yet another aspect of the present invention, a
surface light source apparatus comprises a light guide panel
processed by a laser beam to scatter and diffuse light at a uniform
brightness in an entire area and a light guide pattern portion
having a plurality of grooves satisfying an equation that 1 d ( m )
.times. w ( m ) p ( m ) = 25 65 , wherein the range of t ( mm ) S (
mm 2 ) is 6 .times. 10 - 5 1.2 .times. 10 - 4 ,
[0028] wherein t is a thickness of the light guide panel, S is an
area of a process surface of the light guide panel, d is a process
depth of the light guide pattern portion, w is a line width of each
groove of the light guide pattern, and p is a pitch between the
grooves of the light guide pattern portion, and at least one light
source installed at one side wall of the light guide panel and
emitting light to the light guide panel.
[0029] According to still yet another aspect of the present
invention, a method of manufacturing a surface light source
apparatus comprising the steps of forming a light guide pattern
portion having a plurality of grooves on one surface of a light
guide panel by emitting a laser beam within a range satisfying an
equation that 2 d ( m ) .times. w ( m ) p ( m ) = 25 65 , wherein
the range of t ( mm ) S ( mm 2 ) is 6 .times. 10 - 5 1.2 .times. 10
- 4 ,
[0030] wherein t is a thickness of the light guide panel, S is an
area of a process surface of the light guide panel, d is a process
depth of the light guide pattern portion, w is a line width of each
groove of the light guide pattern, and p is a pitch between the
grooves of the light guide pattern portion, forming at least one
light source installed at one side wall of the light guide panel
and emitting light to the light guide panel, and installing a
reflection panel reflecting the light emitted from the light source
and guided in the light guide panel at a portion corresponding to a
light guide surface where the light guide pattern portion is
formed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The above features of the present invention will become more
apparent by describing in detail preferred embodiments thereof with
reference to the attached drawings in which:
[0032] FIG. 1 is a sectional view illustrating a conventional
surface light source apparatus;
[0033] FIG. 2 is a view illustrating a state in which a light guide
pattern portion is formed on the light guide panel of FIG. 1;
[0034] FIG. 3 is a sectional view illustrating another example of
the conventional surface light source apparatus;
[0035] FIG. 4 is an enlarged sectional view of a portion of FIG.
3;
[0036] FIG. 5 is a view illustrating a state in which the light
guide pattern portion is formed on the light guide panel of FIG.
4;
[0037] FIG. 6 is an exploded perspective view illustrating a
surface light source apparatus according to a preferred embodiment
of the present invention;
[0038] FIG. 7 is an enlarged sectional view taken along line 1-1 of
FIG. 6;
[0039] FIG. 8 is a graph showing an efficiency of light guide
according to a line width of the light guide pattern portion of
FIG. 6;
[0040] FIG. 9 is a view illustrating an apparatus for forming a
light guide pattern portion on a light guide panel according to a
first preferred embodiment of the present invention;
[0041] FIG. 10 is a view illustrating an apparatus for forming a
light guide pattern portion on a light guide panel according to a
second preferred embodiment of the present invention;
[0042] FIG. 11 is a view illustrating an apparatus for forming a
light guide pattern-portion on a light guide panel according to a
third preferred embodiment of the present invention;
[0043] FIG. 12 is a view illustrating a system for forming a light
guide pattern portion on a light guide panel according to a
preferred embodiment of the present invention;
[0044] FIG. 13 is a view illustrating a header moving portion
according to a preferred embodiment of the present invention;
[0045] FIG. 14 is a perspective view illustrating part of the light
guide panel according to the first preferred embodiment of the
present invention;
[0046] FIG. 15 is a perspective view illustrating part of the light
guide panel according to the second preferred embodiment of the
present invention;
[0047] FIG. 16 is a perspective view illustrating part of the light
guide panel according to the third preferred embodiment of the
present invention;
[0048] FIG. 17 is a perspective view illustrating part of the light
guide panel according to the fourth preferred embodiment of the
present invention; and
[0049] FIG. 18 is a view showing a state of forming the light guide
pattern portion on the light guide panel according to a preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0050] Referring to FIGS. 6 and 7, a surface light source apparatus
60 according to a preferred embodiment of the present invention
includes a light guide panel 61. A light guide pattern portion 65
is formed on a lower surface of the light guide panel 61. A
reflection panel 62 reflecting incident light upward is installed
under the light guide panel 61. At least one light source 63
scanning light toward the light guide panel 61 is installed at a
side wall of the light guide panel 62. A CCFL or LED may be used
for the light source 63. Also, a cover member having a reflection
film reflecting light emitted in a direction opposite to the light
guide panel 61 toward the light guide panel 61 can be installed
outside the light source 63.
[0051] A diffusion panel 66 scattering and diffusing light is
further provided above the light guide panel 61. In addition, an
optical diffusion portion formed of fine scratches to have the
light scanned by the light source 63 uniformly diffused to the
front side can be further provided on an upper surface of the light
guide panel 61.
[0052] In the surface light source apparatus 60 having the above
structure, each pattern of the light guide pattern portion 65 can
be formed by scanning a laser beam using a laser system. Processing
hindrance factors such as heat or smoke generated during scanning
of a laser beam can be removed by an additional hindrance
prevention unit. Also; the light guide pattern portion 65 is
processed in the above-described non-contact method to function as
a microlens portion to effectively scatter and diffuse light.
[0053] In detail, the light guide pattern portion 65 formed on of
the light guide panel 61 includes a plurality of grooves having a
predetermined pattern. The light guide pattern portion 65 is
processed in the non-contact method, for example, using a laser
beam output from a laser apparatus which will be described
later.
[0054] The light guide pattern portion 65 is formed throughout the
entire area of the light guide panel 61 to effectively scatter and
diffuse the light emitted from the light source 63 and passing
through the light guide panel 61.
[0055] That is, the light guide pattern portion 65 may be a dot,
rectangular, or grid type formed of grooves, each having a
predetermined depth, or a combination type thereof, a dotted line
type formed of intermittent grooves, each having a predetermined
depth, or a linear type formed of repeated grooves. Also, the size
of the light guide pattern portion 65 gradually increases from the
light source 63 to increase a rate of light scattering and
diffusion, or the pitch in the light guide pattern portion 65 can
be gradually decreased.
[0056] The light guide pattern portion 65 has a profile which is an
irregular saw-toothed shape generated due to vaporization of acryl
resin during process using a laser beam. This fine saw-toothed
shape functions as a micro-lens to improve scattering of light at a
variety of angles.
[0057] When the saw-toothed light guide pattern portion 65 is
processed to a predetermined depth using a laser beam output from a
laser apparatus (not shown), the line width w, the pitch p between
the grooves, and the depth d of the groove are defined by
particular figures or equations.
[0058] That is, the line width w of each groove of the light guide
pattern portion 65 processed by the laser apparatus is preferably
100 through 600 micrometers and the depth d of each groove is 20
through 200 micrometers.
[0059] When the line width w of the light guide pattern portion 65
is over 600 micrometers, a feature of diffusing light in the groove
is deteriorated so that an efficiency of light guide is sharply
lowered. As the diameter of a laser beam output from the laser
apparatus increases, energy density is decreased. Accordingly, the
depth d of the groove generating scattering of light in the light
guide panel 61 is decreased and the line width w is increased.
[0060] When the light guide pattern portion 65 cannot be formed to
have a desired process depth d because the line width w of the
light guide pattern portion 65 is too large, a light diffusion
effect cannot be obtained so that a sufficient brightness is not
obtained. Also, when a high power laser apparatus is used to obtain
a deep process depth with a large line width, light scattering due
to the pattern is generated too strongly.
[0061] Accordingly, when the pitch p of the light guide pattern
portion 65 is decreased, most light is consumed at the light guide
pattern portion 65 close to the light source 63. As a result, the
light uniformity of the light guide panel 61 cannot be obtained.
Also, when the pitch p of the light guide pattern portion 65 is
overly increased, since the pattern is shown, not covered by the
diffusion panel 66, the outer appearance of the surface light
source apparatus 60 is aesthetically deteriorated. Thus, a pitch p
of the grooves of the light guide pattern portion 65 of 0.2 mm
through 2 mm is appropriate.
[0062] On the contrary, when the line width w of the light guide
pattern portion 65 is not more than 100 micrometers, since the
width w of the groove is very narrow, optical energy of the laser
beam output from the laser apparatus does not reach the bottom of
the groove. Accordingly, the process of the light guide pattern
portion 65 having a desired depth is not made properly so that an
efficiency light diffusion effect cannot be obtained.
[0063] As described above, figures concerning the line width w of
each groove of the light guide pattern 65, the process depth d of
each groove, and the pitch p of the groove due to the process using
a laser beam are very important to obtain a uniform brightness of
the light guide panel 61.
[0064] In the meantime, since an optimal brightness and uniformity
change according to the size S and thickness t of the light guide
panel 61, they are important factors in design of the light guide
pattern portion 65.
[0065] The above relationship can be expressed in the following
equation. 3 d ( m ) .times. w ( m ) p ( m ) = 25 65 , wherein the
range of t ( mm ) S ( mm 2 ) is 6 .times. 10 - 5 1.2 .times. 10 - 4
. [ Equation 1 ]
[0066] Here, t is a thickness of the light guide panel 61, S is an
area of a process surface of the light guide panel 61, and d is a
pitch between the grooves of the light guide pattern portion
65.
[0067] When the above values are satisfied, the light guide panel
61 can obtain optimal brightness and uniformity.
[0068] According to the present applicant's experiments, in which
an efficiency of light guide according to the line width w of the
light guide pattern portion 65 of the light guide panel 61 is
measured by the output of the laser apparatus, the optimal line
width w of the light guide pattern portion 65 to be applied to a
large flat panel display device having a thickness of over 8 mm is
about 100 through 600 .mu.m and accordingly the output power of the
laser apparatus should be about 30 through 200 W.
[0069] FIG. 8 shows an efficiency of light guide according to a
change in the line width w of the light guide pattern portion 65 by
the output power of the laser apparatus.
[0070] Referring to the graph of FIG. 8, X axis indicates the line
width w of the light guide pattern portion 65 by 100 .mu.m and Y
axis indicates an efficiency of light guide. The efficiency of
light guide is expressed by a relative brightness I which is the
highest brightness according to a change in the line width of the
light guide pattern portion 65 by the output power of the laser
apparatus, when the light guide panel 61 applied to a 17 inches
flat panel display device having a thickness of 8 mm is divided
into 9 sections, the brightness of a central point of each of the 9
sections is measured, and the average brightness when the
uniformity of brightness is over 70% is set as a reference
I.sub.0.
[0071] Curves A, B, and C form the light guide pattern portion 65
using laser apparatuses having different output powers in a range
of 10-200 W. When the line width of the light guide pattern portion
65 is within a range of 100 through 600 .mu.m, a superior light
guide efficiency close to 1.0 is shown.
[0072] In contrast, when the line width of the light guide pattern
portion 65 is over 600 .mu.m, the feature of diffusing light in the
pattern is deteriorated so that the light guide efficiency is
lowered.
[0073] FIG. 9 shows an apparatus for forming the light guide
pattern portion 65 on the light guide panel 61 according to a first
preferred embodiment of the present invention.
[0074] Referring to FIG. 9, the light guide panel 61 is
accommodated on a plate 91. A surface 61a of the light guide panel
61 where the light guide pattern portion 65 is formed is disposed
to face a header moving portion 900 scanning a laser beam.
[0075] The header moving portion 900 scans a laser beam onto the
light guide panel 61 while moving in vertical and horizontal
directions with respect to the light guide panel 61 by a mechanical
driving by an X Y stage. The structure of a laser system including
the header moving portion 900 will be described later.
[0076] When the head moving portion scans a laser beam having a
wavelength of over 1 .mu.m onto the surface 61a of the light guide
panel 61, the temperature of a focal point of the laser beam and a
portion therearound increase so that a groove having a
predetermined shape can be formed on the surface 61a. As the groove
is formed in the entire area of the light guide panel 61, the light
guide pattern portion 65 is formed.
[0077] When the laser beam is scanned onto a partial area of the
surface 61a of the light guide panel 61, a heating reaction
gradually spreads on the surface 61a due to a change in the width
of the laser beam. When the heating reaction is severe, deformation
of the light guide panel 61 such as a warp phenomenon is
generated.
[0078] The warp phenomenon is generated severely at a peripheral
portion of the light guide panel 61. As a result, an incident angle
of a laser beam changes so that an accurate pattern is difficult to
form. To prevent this, a warp prevention unit is installed at the
light guide panel 61.
[0079] That is, a vacuum portion 910 which can completely suck one
surface of the light guide panel 61 opposite to a surface where the
light guide pattern portion 65 is formed is connected to the plate
91 where the light guide panel 61 is accommodated.
[0080] The vacuum portion 910 includes a plurality of vacuum path
portions 911 which enable vacuum sucking of the light guide panel
61 through the plate 91. The vacuum portion 910, which is a pump
system such as a mechanical vacuum pump, a movement amount transfer
type vacuum pump, or an injection type vacuum pump, can suck a
lower surface of the light guide panel 61 using vacuum through the
vacuum path portions 911 by a pumping force of a pump.
[0081] A vacuum pad 912 can be further provided at a portion where
the light guide panel 61 is sucked, to prevent scratches generated
due to an external force during sucking. Instead of using the
vacuum system, the light guide panel 61 can be fixed by adopting a
coupling method such as joint fixing or clamp fixing using a
physical mechanism.
[0082] In the state of fixing the light guide panel 61 using the
warp prevention unit, a laser beam is scanned to form the light
guide pattern portion 65. Accordingly, the warp phenomenon due to
partial heating of the laser beam can be prevented in advance.
[0083] FIG. 10 shows an apparatus for forming the light guide
pattern portion 65 on the light guide panel 61 according to a
second preferred embodiment of the present invention. Here, the
same reference numerals indicate the same elements having the same
functions.
[0084] Referring to FIG. 10, the light guide panel 61 is
accommodated on the plate 91. The scanning surface 61a of the light
guide panel 61 is disposed to face the laser header moving portion
900 which scans a laser beam. A vacuum path portion 911 for sucking
the light guide panel 61 using vacuum is formed in the plate 91.
The vacuum path portion 911 is connected to the vacuum portion 910
which is a vacuum pump system providing a vacuum force. The vacuum
pad 912 to prevent scratches on a surface of the light guide panel
61 sucked during vacuum sucking is installed on a path of the
vacuum path portion 911.
[0085] A warp prevention unit can be additionally installed in
preparation for a case when a close contact force of the plate 91
to the light guide panel 61 is not sufficient during scanning of a
laser beam output from the laser system, while maintaining
levelness of the light guide panel 61 by a vacuum system.
[0086] That is, a heating portion 1000 is installed at the plate
91. The heating portion 1000 includes a heat wire 1010 installed in
the plate 91 and electrically generating heat. Alternatively, the
plate 91 can be heated by heat generated by an ultrasonic wave and
the heat may be transferred to the light guide panel 61.
[0087] When a predetermined heat is applied to the plate 91, the
heat of the plate 91 is transferred to the opposite side of the
light guide pattern portion 65 of the light guide panel 61 as much
as the temperature increased by the laser beam scanning onto the
scanning surface 61a of the light guide panel 61. Accordingly, the
deviation of temperature between upper and lower portions of the
light guide panel 61 can be removed so that a warp phenomenon can
be prevented in advance.
[0088] In the meantime, since the etching method by scanning of a
laser beam onto the light guide panel 61 is to heat the surface of
the light guide panel 61 made of acryl resin with strong energy,
smoke is generated due to vaporized an acryl resin material. The
smoke causes absorption or scattering of a laser beam during the
scanning process to form the light guide pattern portion 65 on the
light guide panel 61. Accordingly, energy of the laser beam scanned
onto the light guide panel 61 is reduced and the process of the
light guide pattern portion 65 of a desired pattern is
prevented.
[0089] FIG. 11 shows an apparatus for forming the light guide
pattern portion 65 on the light guide panel 61 according to a third
preferred embodiment of the present invention to remove the above
phenomenon.
[0090] Referring to FIG. 11, the light guide panel 61 is
accommodated on the plate 91. The vacuum portion 910 which is a
vacuum pump system for supplying vacuum to the light guide panel 61
is installed and connected to the plate 91 via the vacuum path
portion 911. The vacuum pad 912 is installed on a surface of the
light guide panel 61 which is sucked.
[0091] When part of the light guide panel 61 is removed by heat
energy during scanning of a laser beam using the laser header
moving portion 900, smoke s is generated from the scanning surface
61a of the light guide panel 61. The smokes can be removed by an
absorption and scattering prevention unit.
[0092] That is, an air blow portion 1100 for removing the smoke s
is installed at one side of the light guide panel 61. The air blow
portion 1100 blows air to the scanning surface 61a of the light
guide panel 61 through an air blow pipe 1101 by injecting gas over
the atmospheric pressure. The air blow portion 1100 removes the
smoke s from the light guide panel 61 and simultaneously cools the
scanning surface 61a of the light guide panel 61.
[0093] An air exhaust portion 1110 for removing the smoke s blown
by the air blow portion 1100 is installed at the opposite side of
the light guide panel 61. The air exhaust portion 1110 sucks and
discharges the smoke s vaporized from the scanning surface 61a of
the light guide panel 61 which is made of acryl resin, so that
absorption or scattering of a laser beam due to the smoke s can be
prevented.
[0094] FIG. 12 shows a system for forming the light guide pattern
portion on the light guide panel according to a preferred
embodiment of the present invention.
[0095] Referring to FIG. 12, a pattern forming system 120 includes
a pattern design system 121, a control system 122, a laser system
123, a header moving portion 124, a lens portion 125, a warp
prevention unit for preventing warp of the light guide panel 61,
and an absorption and scattering prevention unit for preventing
absorption and scattering of a laser beam.
[0096] The header moving portion 124 includes an X-Y moving portion
126 which can be mechanically moved in X-Y direction, and a
plurality of mirror header portions 127 coupled to the X-Y moving
portion 126 to reflect a laser beam scanned by the laser system 123
toward the light guide panel 121.
[0097] In the operation of the pattern forming system 120 having
the above structure according to the present invention, data of
design rules of each pattern of the light guide pattern portion 65
to be formed on the light guide panel is input to the pattern
design system 121. A position signal corresponding to an area of
the scanning surface 61a of the light guide panel 61 to be scanned
which matches coordinate values of each pattern is transferred to
the header moving portion 124 via the control system 122.
[0098] A pulse signal synchronized with a mechanical movement of
the header moving portion 124 in vertical and horizontal directions
is transferred to the laser system 123 via the control system 122.
The laser system 123 emits a laser beam.
[0099] The laser beam is reflected by the mirror header portions
127 and scanned onto the scanning surface 61a of the light guide
panel 61 via the lens portion 125, so that the surface of the light
guide panel 61 is processed. Accordingly, the light guide pattern
portion 65 such as a dot pattern is formed on the scanning surface
61a of the light guide panel 61.
[0100] In this state, to prevent a warp phenomenon generated due to
local heating of a laser beam output from the laser system 123, a
vacuum force is supplied to the light guide panel 61 via the vacuum
path portion 911 by operating a pump of the vacuum portion 910
connected to the plate 91 on which the light guide panel 61 is
accommodated. Thus, the light guide panel 61 is vacuum-sucked
against the plate 91 so that the entire area maintains
levelness.
[0101] Also, when the close contact force of the light guide panel
61 by the vacuum unit is not sufficient with respect to the plate
91, a predetermined electric power is applied from the heating
portion 1000 connected to the plate 91 to the light guide panel 61
to remove a difference in the temperature between the upper and
lower surfaces of the light guide panel 61, so that the warp
phenomenon can further be prevented.
[0102] In the meantime, to prevent the smoke generated from the
light guide panel 61 which preventing the pattern process, air
under a predetermined pressure is blown from the air blow portion
1100 installed at one side of the light guide panel 61 toward the
scanning surface 61a.
[0103] The smoke removed by the air blow portion 1100 is exhausted
by being sucked by the air exhaust portion 1110 installed at the
other side of the light guide panel 61. As a result, the laser beam
absorption and scattering phenomenon can be prevented.
[0104] FIG. 13 shows a header moving portion according to a
preferred embodiment of the present invention.
[0105] Referring to FIG. 13, a header moving portion 130 includes
an XY moving portion 131 which is mechanically movable in X and Y
directions, and a plurality of mirror header portions 133 coupled
to the XY moving portion 131 to reflect a laser beam output from
the laser system 132 installed at one side of the header moving
portion 130, toward the light guide panel.
[0106] A horizontal guide rail 134 arranged in the direction X is
installed at the XY moving portion 131. Each of the mirror head
portions 133 includes first and second mirror header portions 133a
and 133b.
[0107] The first mirror header portion 133a is installed on the
horizontal guide rail 134. The second mirror header portion 133b is
coupled to the horizontal guide rail 134 capable of moving along
the horizontal guide rail 134.
[0108] A horizontal linear motor 135 is installed on the horizontal
guide rail 134 so that the second mirror header portion 133b can
horizontally move along the horizontal guide rail 134. The
horizontal linear motor 135 is a horizontal movement supply source
connected to the second mirror header portion 133b.
[0109] A focus lens portion 136 is coupled to the second mirror
header portion 133b and the focus lens portion 136 can move
horizontally together with the second mirror header portion
133b.
[0110] A plurality of vertical guide rails 137 are installed at
both ends of the horizontal guide rail 134. At least one vertical
linear motor 138 is installed on the vertical guide rail 137. The
horizontal guide rail 134 can be moved vertically along the
vertical guide rail 137 by the vertical linear motor 138.
[0111] As described above, at least one mirror header portion 133
can be moved horizontally along the horizontal guide rail 134 by
the horizontal linear motor 135 while the horizontal guide rail 134
can be moved vertically along the vertical guide rail 137 by the
vertical linear motor 138.
[0112] In this state, an optical output signal transferred to the
laser system 132, a horizontal transfer signal transferred to the
horizontal linear motor 135, and a vertical transfer signal
transferred to the vertical linear motor 138 are transmitted from a
control system 139.
[0113] In the operation of the header moving portion 130 having the
above structure, a pulse signal synchronized with the speed of
movement of the second mirror header portion 133b mechanically
transferred by a transfer signal of the control system 139 is
transferred to the laser system 132 through the control system 139,
so that the laser system 132 emits a laser beam.
[0114] The laser beam emitted from the laser system 132 proceeds
toward the first mirror header portion 133a fixed at one side of
the horizontal guide rail 134 and reflected by a mirror of the
first mirror header portion 133a to proceed toward the second
mirror header portion 133b. Then, the laser beam is perpendicularly
reflected by a mirror of the second mirror header portion 13b and
passes through the focus lens portion 136 so as to be incident on
the scanning surface 61a of the light guide panel 61 to form the
light guide pattern portion 65. When the second mirror header
portion 133b is moved in the horizontal direction in a process area
A by the horizontal linear motor 135, the laser beam is output in
the horizontal direction to form the light guide pattern portion
65.
[0115] Since the vertical guide rail 137 is coupled to both end
portions of the horizontal guide rail 134, the horizontal guide
rail 134 can be moved vertically along the vertical guide rail 137
by the vertical linear motor 138 receiving the vertical transfer
signal output from the control system 139. Thus, the laser beam is
output in the vertical direction of the light guide panel 61 so
that the light guide pattern portion 65 can be formed.
[0116] The shape of the light guide pattern portion manufactured by
using the above-described system for forming the light guide
pattern portion will now be described.
[0117] According to the characteristic feature of the present
invention, in order to effectively scatter and diffuse the light
incident on the lower surface of the light guide panel, a light
guide pattern portion having an intermittent shape is formed by a
laser process throughout the entire area of the light guide panel.
The light guide pattern portion, which is a group of a
discontinuous shape separated by a predetermined pitch, is formed
by a predetermined design rule.
[0118] FIG. 14 shows a light guide panel where a light guide
pattern portion according to a first preferred embodiment is
formed. Here, a pitch P of a groove in a vertical direction is a
pitch between neighboring grooves in a direction perpendicular to a
direction along which the light source is arranged, a length L of
the groove is the length of each groove in a direction parallel to
the direction along which the light source is arranged, and a pitch
W of the groove in a horizontal direction is a pitch between
neighboring grooves in the direction parallel to the direction
along which the light source is arranged.
[0119] Referring to FIG. 14, a light guide pattern portion 145 is
formed on one surface of a light guide panel 140. The light guide
pattern portion 145 has a shape of discontinuous dotted lines and
includes a plurality of grooves. The respective grooves are
separated by a predetermined pitch.
[0120] The light guide pattern portion 145 is formed on the
scanning surface 141 of the light guide panel 140 according to a
predetermined design rule by the relationship of a relative
position with respect to the light source 143.
[0121] That is, the light source 143 is installed at one wall 142
of the light guide panel 140. In the light guide pattern portion
145, a plurality of grooves are intermittently formed along a
lengthwise direction of the light source 143 such that the length
L1 of the groove in an area of the light guide panel 140 close to
the light source 143 is shorter than that of the groove in the
remaining area of the light guide panel 140.
[0122] In contrast, as the grooves are separated farther from the
light source 143, the length L2 of the groove on the light guide
panel 140 is formed greater than the length L1 of the groove in the
area close to the light source 143.
[0123] The pitch P1 between the grooves in the peripheral portion
of the light guide portion 141 close to the light source 143 is
substantially the same as the pitch P2 between the grooves of the
light guide panel 141 separated the farthest distance from the
light source 143.
[0124] When the light source 143 is installed at both side walls of
the light guide panel 140, the central portion of the light guide
panel 140 is the farthest portion from the light source 143.
Accordingly, the groove of the light guide pattern portion 145 at
the central portion of the light guide panel 140 has the longest
length throughout the entire area of the light guide panel 140. In
contrast, the groove in the peripheral area of the light guide
panel 140 has the shortest length.
[0125] As separated away from the light source 143, the grooves are
formed on the light guide panel 140 such that the lengths of the
grooves of the light guide pattern portion 145 gradually increase.
The grooves are formed in a shape of discontinuous dotted lines
along a direction parallel to the light source 143.
[0126] Accordingly, as separated away from the light source 143
installed at the side wall 142 of the light guide panel 140, the
length of each groove in the light guide pattern portion 140 having
an intermittent straight line shape gradually increases so that the
amount of light guide is increased. Thus, lowering of brightness
due to being separated away from the light source 143 can be
prevented. Also, a uniform brightness can be obtained from the
entire area of the light guide panel 140.
[0127] The light guide pattern portion 140 formed of a plurality of
grooves having a straight line shape can be easily formed by the
mechanical driving by the system shown in FIG. 12 to form the light
guide pattern portion.
[0128] That is, the mirror header portion 127 capable of moving
along a lengthwise direction in which the light source 143 is
installed which is the X-axis direction of the light guide panel
140 moves at a constant speed and forms each groove of the light
guide pattern portion 145 at a desired position by reflecting the
laser beam output from the laser system 123 by the light guide
panel 140.
[0129] The lengths of the grooves formed on the light guide panel
140 are different from one another. The different lengths of the
grooves can be easily processed by controlling an electric signal
to a position signal corresponding to a coordinate value of each
pattern input to the control system 122, not by the mechanical
control of the mirror header portion 127.
[0130] In relation to the mirror header portion 127 moving in the
horizontal direction of the light guide panel 140, since each
groove of the light guide pattern portion 145 formed on the light
guide panel 140 has a straight line shape, the light guide pattern
portion 145 can be formed without a dark line or a bright line.
[0131] FIG. 15 shows a light guide panel where a light guide
pattern portion according to a second preferred embodiment of the
present invention is formed.
[0132] Referring to FIG. 15, a light guide pattern portion 155
including a plurality of grooves having an intermittent straight
line shape is formed on a light guide panel 150. The respective
grooves of the light guide pattern portion 155 are formed on a
scanning surface 151 of the light guide panel 150 by a
predetermined design rule according to a relative relationship with
a light source 153 installed at one side wall 152 of the light
guide panel 150.
[0133] The grooves of the light guide pattern portion 155 are
formed throughout the process area of the light guide panel 150 to
have a different interval therebetween. That is, pitch P3 between
the grooves at the peripheral portion of the light guide panel 150
close to the light source 153 is greater than pitch P4 between the
grooves at the central portion relatively far from the light source
153.
[0134] Also, the pitch between the grooves gradually decreases from
the area close to the light source 153 to the central portion of
the light guide panel 150. In the meantime, the length L3 of the
groove at the peripheral portion of the light guide panel 150 is
substantially the same as the length L4 of the groove at the
central portion.
[0135] Thus, the pitch between the grooves of the light guide
pattern portion 155 varies to be gradually decreased on the light
guide panel 150 as the grooves are positioned far from the light
source 153. Each of the grooves is formed to have an intermittent
straight line shape in a direction in which the light source 153 is
installed.
[0136] Accordingly, although the grooves are positioned far from
the light source 153, since the interval between the grooves of the
light guide pattern portion 155 decreases, the amount of light
guide increases so that the lowering of brightness can be
prevented. The grooves of the light guide pattern portion 155 can
be processed by the above-described system to form the light guide
pattern portion.
[0137] FIG. 16 shows a light guide panel where a light guide
pattern portion according to a third preferred embodiment of the
present invention is formed.
[0138] Referring to FIG. 16, a light guide pattern portion 165
including a plurality of grooves having an intermittent straight
line shape is formed by using a laser beam on a light guide panel
160. The respective grooves of the light guide pattern portion 165
are different in their lengths and pitches according to the
distance from the light source 163.
[0139] That is, the length L5 of the groove at the peripheral
portion of the light guide panel 160 close to the light source 163
installed at one side wall 162 of the light guide panel 160 is
shorter than the length L6 of the groove at the central portion of
the light guide panel 160 relatively far from the light source 163.
In the meantime, pitch P5 between the grooves at the peripheral
portion of the light guide panel 160 is greater than pitch P6
between the grooves at the central portion of the light guide panel
160.
[0140] Also, from the peripheral portion of the light guide panel
160 close to the light source 163 to the central portion of the
light guide panel 160, the length of each groove gradually
increases while the pitch between the grooves gradually
decreases.
[0141] Thus, the length of each groove and the pitch between the
grooves of the light guide pattern portion 165 are varied as the
grooves are positioned on the light guide panel 160 far from the
light source 163. Each of the grooves is formed in an intermittent
straight line shape along a direction in which the light source 163
is installed.
[0142] The light guide pattern portion 165 having the above shape
is process such that a desired pattern is formed by time control as
the mirror header portion 127 of the above-described system to form
the light guide pattern portion is horizontally moved at a constant
speed above the scanning surface 146 of the light guide panel 160
while receiving an electric signal about the length of each groove
and the pitch between the grooves.
[0143] FIG. 17 shows a light guide panel where a light guide
pattern portion according to a fourth preferred embodiment of the
present invention is formed.
[0144] Referring to FIG. 17, a light guide pattern portion 175
including a plurality of grooves having an intermittent straight
line shape is formed on a light guide panel 170. The respective
grooves of the light guide pattern portion 175 are formed on a
scanning surface 171 of the light guide panel 170 by a
predetermined design rule according to a relative relationship with
a light source 173 installed at one side wall 172 of the light
guide panel 170.
[0145] The respective grooves of the light guide pattern portion
175 are formed to have different pitches W1 and W2 in a horizontal
direction throughout a processing area of the light guide panel
173. That is, the pitch W1 between the grooves at the peripheral
portion of the light guide panel 170 close to the light source 173
is greater than the pitch W2 between the grooves at the central
portion which is relatively far from the light source 173. Also,
the interval between the grooves gradually decreases from the
peripheral portion of the light guide panel 170 close to the light
source 173 and the central portion of the light guide panel
170.
[0146] In the meantime, the length L7 of each groove and the pitch
P7 between the grooves at the peripheral portion of the light guide
panel 170 are substantially the same as the length L8 of each
groove and the pitch P8 between the grooves at the central portion.
The respective grooves of the light guide pattern portion 175 are
processed by the above-described system to form the light guide
pattern portion.
[0147] In the above light guide panel 170, the interval between the
grooves of the light guide pattern portion 175 gradually decreases
as the groove is positioned far from the light source 173. Each of
the grooves is formed to have an intermittent straight line shape
along a direction in which the light source 173 is installed.
[0148] Accordingly, although the grooves are positioned far from
the light source 173, since the interval between the grooves of the
light guide pattern portion 175 decreases, the amount of light
guide increases so that the lowering of brightness can be
prevented. The grooves of the light guide pattern portion 175 can
be processed by the above-described laser system to form the light
guide pattern portion.
[0149] The shape of the light guide pattern portion is not limited
to the above-described preferred embodiments and any structure
enabling the reflection, scattering, and diffusion of light output
from the light source can be adopted. Also, in the above preferred
embodiments, a uniform brightness can be obtained by adjusting a
scattering feature of the amount of light guide by mixing the
structures to vary the length of each groove, the width between the
grooves, and the pitch between the grooves as the groove is
positioned far from the light source.
[0150] FIG. 18 shows a state of forming a light guide pattern
portion by emitting a laser beam onto a light guide panel having a
thickness deviation t.sub.3 according to a preferred embodiment of
the present invention.
[0151] Referring to FIG. 18, a perfect flat surface without a
deviation is not available in a light guide panel 181 and a
deviation in the thickness of the light guide panel 181 is
typically about .+-.100 .mu.m. When a laser beam is emitted on the
light guide panel 181, a light guide pattern portion 185 having an
inclined surface having a saw-toothed shape is formed. Here, a
deviation with respect to the process depth of the light guide
pattern portion 185 is about .+-.20 .mu.m.
[0152] Even when the thickness of the light guide panel 181 has a
deviation of .+-.100 .mu.m, since a method of processing using a
laser beam has a great light condensation property, the size of a
diameter of a laser beam according to a change in the distance is
not great. Thus, processing is possible over the entire area on the
light guide panel 181 except for the deviation to the process depth
in a state of excluding an effect on the deviation in the thickness
of the light guide panel 181.
[0153] As described above, the surface light source apparatus, the
method of manufacturing the same, and the apparatus for
manufacturing the same according to the present invention can
obtain the following effects.
[0154] First, as at least one of the mirror header portion can be
mechanically moved vertically and horizontally on the X-Y moving
portion, a light guide pattern portion can be processed on a raw
material of a large sized light guide panel.
[0155] Second, since the output of the laser system can be
increased, the movement speed of the header moving portion is
increased so that the processing time can be reduced.
[0156] Third, since an expensive laser scanner is not used, the
cost of an equipment for forming a light guide forming portion of
the light guide panel can be reduced.
[0157] Fourth, since the incident angle of the laser beam does not
change according to the position, a phenomenon that the light guide
pattern portion is deformed can be prevented.
[0158] Fifth, a phenomenon that the light guide panel is partially
bent due to the heat generated during the scanning performed on the
light guide panel using a laser beam is prevented.
[0159] Sixth, a phenomenon that the energy of a laser beam is
reduced since a light absorption and scattering phenomenon is
generated due to smoke generated when the light guide pattern
portion is formed is prevented in advance.
[0160] Seventh, since a light guide pattern portion having an
intermittent and linear shape is formed on the light guide panel,
an error due to the mechanical movement of the header moving
portion of the laser processing apparatus in the vertical and
horizontal directions can be reduced. Accordingly, a light guide
pattern portion of a fine pattern can be processed without an
error.
[0161] Eighth, since the light guide pattern portion having an
intermittent shape is formed by outputting a laser beam from the
laser processing apparatus according to the time control by
transferring an electric signal not by a mechanical control, the
defectiveness of a desired pattern can be prevented in advance.
[0162] Ninth, since the inner surface of each groove of the light
guide pattern portion is saw-toothed, the groove can function as a
microlens so that the scattering of light is improved. Accordingly,
the amount of the light scattering portion additionally installed
on the light guide panel can be reduced.
[0163] Tenth, since processing is performed in a non-contact method
using a laser beam exhibiting a superior light condensation
property, even when a distribution of the thickness of the light
guide panel exists, a process error is hardly generated. Thus,
since processing is possible by using a raw material of a light
guide panel having a relatively greater thickness deviation, the
raw cost of the material can be remarkably reduced.
[0164] Eleventh, since a method of scanning a laser beam onto the
light guide panel is used, a mask or mold used for a printing or
stamping method is not necessary so that a development and
manufacturing period can be remarkably reduced.
[0165] Twelfth, since a method of engraving-processing the light
guide panel itself using a laser beam is adopted, a light
absorption loss is not generated on the light guide panel due to
the use of additional material such as a print material so that the
efficiency of light is greatly improved.
[0166] Thirteenth, when the light guide panels having different
sizes are processed, since an additional apparatus according to the
different sizes is not additionally needed, mass production is
improved.
[0167] Fourteenth and the last, when the wasted surface light
source apparatus is collected and recycled, since there is no
attachment material such as a print material, the cost of recycling
of a product is lowered.
[0168] While this invention has been particularly shown and
described with reference to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
spirit and scope of the invention as defined by the appended
claims.
* * * * *