U.S. patent application number 12/314533 was filed with the patent office on 2010-06-17 for brightness enhancement film and backlight module.
Invention is credited to Yi-Fan Chen, Chi-Feng Lin.
Application Number | 20100150509 12/314533 |
Document ID | / |
Family ID | 42240632 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100150509 |
Kind Code |
A1 |
Lin; Chi-Feng ; et
al. |
June 17, 2010 |
BRIGHTNESS ENHANCEMENT FILM AND BACKLIGHT MODULE
Abstract
The present invention relates to a brightness enhancement film
and a backlight module having the brightness enhancement film. The
brightness enhancement film includes first micro-reflectors and
second micro-reflectors. The cross-section of each of the first and
second micro-reflectors is a triangle having two same or different
base angles and a wavy crest line. The widths of the first and
second micro-reflectors vary along with the valleys and peaks to
broaden or to narrow with respect to two sides thereof such that
the neighboring lines between the first and second micro-reflectors
are wavy. The backlight module is coupled with the brightness
enhancement film. This enhances brightness, illuminates evenly, and
avoids a moire effect.
Inventors: |
Lin; Chi-Feng; (US) ;
Chen; Yi-Fan; (US) |
Correspondence
Address: |
ROSENBERG, KLEIN & LEE
3458 ELLICOTT CENTER DRIVE-SUITE 101
ELLICOTT CITY
MD
21043
US
|
Family ID: |
42240632 |
Appl. No.: |
12/314533 |
Filed: |
December 12, 2008 |
Current U.S.
Class: |
385/129 |
Current CPC
Class: |
G02B 6/0055 20130101;
G02B 6/0053 20130101; Y10S 385/901 20130101 |
Class at
Publication: |
385/129 |
International
Class: |
G02B 6/10 20060101
G02B006/10 |
Claims
1. A brightness enhancement film, comprising: a pair of first sides
corresponding to each other, a pair of second sides corresponding
to each other, and a plurality of first micro-reflectors and second
micro-reflectors disposed side by side; said first micro-reflectors
having a first average height and a first average width, said
second micro-reflectors having a second average height and a second
average width, said first average height and said first average
width being different from said second average height and said
second average width, each of said first micro-reflectors and said
second micro-reflectors having a triangular cross-section viewed
from the first side, said triangular cross-section having an apex
and a base, said apex of said triangular cross-section defining a
crest line extending longitudinally from the first side,
neighboring lines being disposed between crest lines to delineate
adjacent ones of said first micro-reflectors and said second
micro-reflectors, said crest lines of said first and second
micro-reflectors each defining a straight horizontal profile and a
wavy vertical profile having continuous valleys and peaks, said
first micro-reflectors being longitudinally offset in vertical
profile from said second micro-reflectors, the widths of said first
micro-reflectors and said second micro-reflectors varying along
with said valleys and said peaks, said neighboring lines between
said first micro-reflectors and said second micro-reflectors being
wavy.
2. The brightness enhancement film, as claimed in claim 1, wherein
the valley of each said first micro-reflector has an equal height
with respect to the peak of each said second micro-reflector.
3. The brightness enhancement film, as claimed in claim 1, wherein
the valley of each said first micro-reflector has a different
height with respect to the peak of each said second
micro-reflector.
4. The brightness enhancement film, as claimed in claim 1, wherein
each of said first micro-reflectors and said second
micro-reflectors has a triangular cross-section having two same
base angles.
5. The brightness enhancement film, as claimed in claim 1, wherein
each of said fist micro-reflectors and said second micro-reflectors
has a triangular cross-section having two different base
angles.
6. The brightness enhancement film, as claimed in claim 1, wherein
said first and second average heights of said first
micro-reflectors and said second micro-reflectors are average
values of the perpendicular heights of said first micro-reflectors
and said second micro-reflectors.
7. The brightness enhancement film, as claimed in claim 1, wherein
said first and second average widths of said first micro-reflectors
and said second micro-reflectors are average values of the width
taken from a bottom of the cross-section of each of said first
micro-reflectors and said second micro-reflectors.
8. A backlight module, comprising: at least one light source; a
light guide plate having at least a ray entering side and a ray
displaying side, said ray entering side being adapted to receive
ray from said light source and said ray displaying side being
adapted to guide the ray outward; and a brightness enhancement film
disposed on said ray displaying side of said light guide plate,
said brightness enhancement film comprising: a pair of first sides
corresponding to each other, a pair of second sides corresponding
to each other, and a plurality of first micro-reflectors and second
micro-reflectors disposed side by side, said first micro-reflectors
having a first average height and a first average width, said
second micro-reflectors having a second average height and a second
average width, said first average height and said first average
width being different from said second average height and said
second average width, each of said first micro-reflectors and said
second micro-reflectors having a triangular cross-section viewed
from the first side, said triangular cross-section having an apex
and a base, said apex of said triangular cross-section defining a
crest line extending longitudinally from the first side,
neighboring lines being disposed between crest lines to delineate
adjacent ones of said first micro-reflectors and said second
micro-reflectors, said crest lines of said first and second
micro-reflectors each defining a straight horizontal profile and a
wavy vertical profile having continuous valleys and peaks, said
first micro-reflectors being longitudinally offset in vertical
profile from said second micro-reflectors, the widths of said first
micro-reflectors and said second micro-reflectors varying along
with said valleys and said peaks, said neighboring lines between
said first micro-reflectors and said second micro-reflectors being
wavy.
9. The backlight module, as claimed in claim 8, wherein the valley
of each said first micro-reflector has an equal height with respect
to the peak of each said second micro-reflector
10. The backlight module, as claimed in claim 8, wherein the valley
of each said first micro-reflector has a different height with
respect to the peak of each said second micro-reflector.
11. The backlight module, as claimed in claim 8, wherein each of
said first micro-reflectors and said second micro-reflectors has a
triangular cross-section having two same base angles.
12. The backlight module, as claimed in claim 8, wherein each of
said fist micro-reflectors and said second micro-reflectors has a
triangular cross-section having two different base angles.
13. The backlight module, as claimed in claim 8, wherein said first
and second average heights of said first micro-reflectors and said
second micro-reflectors are average values of the perpendicular
heights of said first micro-reflectors and said second
micro-reflectors.
14. The backlight module, as claimed in claim 8, wherein said first
and second average widths of said first micro-reflectors and said
second micro-reflectors are average values of the width taken from
a bottom of the cross-section of each of said first
micro-reflectors and said second micro-reflectors.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a brightness enhancement
film and a backlight module having the brightness enhancement film,
and more particularly to a brightness enhancement film having first
and second micro-reflectors in different average heights and widths
and wavy crest lines. The widths of the first and second
micro-reflectors vary along with valleys and peaks thereof. The
neighboring lines between the first and second micro-reflectors are
wavy. This enhances brightness, illuminates evenly, and avoids a
moire effect.
[0003] 2. Description of the Prior Art
[0004] A backlight module A of a conventional LCD display, as shown
in FIG. 9, comprises a light guide plate A1, a light source A2, a
reflector A3, a diffusion film A4, and a brightness enhancement
film A5. The light source A2 is disposed at one side of the light
guide plate A1 to provide light from a ray entering side A6 to the
light guide plate A1 to reflect therein and emit from a ray
displaying side A7. The light will then emits through the diffusion
film A4 and the brightness enhancement film A5 and reaches to a LCD
panel B. The brightness enhancement film A5 can accumulate the
light to increase the light as well as to illuminate evenly.
[0005] In order to accumulate illumination for a brightness
enhancement film to increase the brightness and to illuminate
evenly, the surface of the film comprises a number of prisms. As
taught in U.S. Pat. No. 5,917,664, a brightness enhancement film
has a plurality of linear prisms. The prisms are disposed in pairs,
each pair having first and second prisms and each prism has a prism
angle and a valley angle. Either the prism angles or the valley
angles, but not both, are equal. However, it does not have the
function of accumulating light.
[0006] Taiwanese Patent No. I274896 disclosed "an enhancing
structure for a light accumulating device", which comprises a light
accumulating device on a baseboard. The light accumulating device
has at least a wavy extension surface to enhance light accumulating
efficiency. However, this design can not diffuse the light evenly
on the display.
[0007] Taiwanese Patent No. I278662 disclosed "an optical film
structure", which comprises micro-prisms formed on an optical film.
Each micro-prism has at least two peaks in different heights,
preventing the ray from producing interference strips. However, it
downgrades the accumulation of light.
SUMMARY OF THE INVENTION
[0008] According to a first aspect of the present invention, there
is provided a brightness enhancement film comprising a pair of
first sides corresponding to each other, a pair of second sides
corresponding to each other, and a number of first micro-reflectors
and second micro-reflectors disposed side by side, said first
micro-reflectors having a first average height and a first average
width, said second micro-reflectors having a second average height
and a second average width, said first average height and said
first average width being different from said second average height
and said second average width, each of said first micro-reflectors
and said second micro-reflectors having a cross-section which is a
triangle viewed from the first side, said triangle having an apex
and a base, said apex of said triangle forming a crest line viewed
from the second side, two sides of said crest line being connecting
points of said triangle, said connecting points forming neighboring
lines of said first micro-reflector and said second
micro-reflector, said crest line being wavy having continuous
valleys and peaks, the widths of said first micro-reflectors and
said second micro-reflectors varying along with said valleys and
said peaks, said neighboring lines between said first
micro-reflectors and said second micro-reflectors being wavy.
[0009] Preferably, the valley of each said first micro-reflector
has an equal height with respect to the peak of each said second
micro-reflector.
[0010] Preferably, the valley of each said first micro-reflector
has a different height with respect to the peak of each said second
micro-reflector.
[0011] Preferably, each of said first micro-reflectors and said
second micro-reflectors has a triangular cross-section having two
same base angles.
[0012] Preferably, each of said first micro-reflectors and said
second micro-reflectors has a triangular cross-section having two
different base angles.
[0013] Preferably, said first and second average heights of said
first micro-reflectors and said second micro-reflectors are average
values of the perpendicular heights of said first micro-reflectors
and said second micro-reflectors.
[0014] Preferably, said first and second average widths of said
first micro-reflectors and said second micro-reflectors are average
values of the width taken from a bottom of the cross-section of
each of said first micro-reflectors and said second
micro-reflectors.
[0015] According to a second aspect of the present invention, there
is provided a backlight module, comprising at least a light source;
a light guide plate having at least one ray entering side and a ray
displaying side, said ray entering side being adapted to receive
ray from said light source and said ray displaying side being
adapted to guide the ray outward; and a brightness enhancement film
disposed on said ray displaying side of said light guide plate,
said brightness enhancement film comprising a pair of first sides
corresponding to each other, a pair of second sides corresponding
to each other, and a number of first micro-reflectors and second
micro-reflectors disposed side by side, said first micro-reflectors
having a first average height and a first average width, said
second micro-reflectors having a second average height and a second
average width, said first average height and said first average
width being different from said second average height and said
second average width, each of said first micro-reflectors and said
second micro-reflectors having a cross-section which is a triangle
viewed from the first side, said triangle having an apex and a
base, said apex of said triangle forming a crest line viewed from
the second side, two sides of said crest line forming connecting
points of said triangle, said connecting points being neighboring
lines of said first micro-reflectors and said second
micro-reflectors, said crest line being wavy having continuous
valleys and peaks, the widths of said first micro-reflectors and
said second micro-reflectors varying along with said valleys and
said peaks, said neighboring lines between said first
micro-reflectors and said second micro-reflectors being wavy.
[0016] Preferably, the valley of each said first micro-reflector
has an equal height with respect to the peak of each said second
micro-reflector
[0017] Preferably, the valley of each said first micro-reflector
has a different height with respect to the peak of each said second
micro-reflector.
[0018] Preferably, each of said first micro-reflectors and said
second micro-reflectors has a triangular cross-section having two
same base angles.
[0019] Preferably, each of said first micro-reflectors and said
second micro-reflectors has a triangular cross-section having two
different base angles.
[0020] Preferably, said first and second average heights of said
first micro-reflectors and said second micro-reflectors are average
values of the perpendicular heights of said first micro-reflectors
and said second micro-reflectors.
[0021] Preferably, said first and second average widths of said
first micro-reflectors and said second micro-reflectors are average
values of the width taken from a bottom of the cross-section of
each of said first micro-reflectors and said second
micro-reflectors.
[0022] The present invention has the following advantages: [0023]
1. The first and second micro-reflectors having different heights
and widths are disposed side by side on the brightness enhancement
film in a wavy shape, providing better brightness and illuminating
evenly. [0024] 2. The first and second micro-reflectors have peaks
and valleys to hold against the diffusion film, preventing the
brightness enhancement film from distortion or damage. [0025] 3.
The valleys of the first and second micro-reflectors enable to
collect light ray for better brightness, avoiding a moire
effect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a perspective view of a brightness enhancement
film of the present invention;
[0027] FIG. 2 is an enlarged sectional view of FIG. 1;
[0028] FIG. 3 is a cross-sectional view of FIG. 1 showing first
micro-reflectors and second micro-reflectors;
[0029] FIG. 4 is a schematic view showing the variation of the
heights of the first micro-reflectors and the second
micro-reflectors;
[0030] FIG. 5 is a schematic view showing the variation of the
widths of the first micro-reflectors and the second
micro-reflectors;
[0031] FIG. 6 is an exploded view of a backlight module
incorporated with the brightness enhancement film of the present
invention;
[0032] FIG. 7 is a cross-sectional view of the present invention
showing the first micro-reflectors and the second micro-reflectors
with two different base angles;
[0033] FIG. 8 is a luminosity plot of a backlight module with or
without the brightness enhancement film; and
[0034] FIG. 9 is an exploded view of the prior art.
DETAILED DESCRIPTION OF THE REFERRED EMBODIMENTS
[0035] As shown in FIGS. 1 and 2, a brightness enhancement film 1
of the present invention comprises a pair of first sides 11
corresponding to each other, a pair of second sides corresponding
to each other, and a number of first micro-reflectors 13 and second
micro-reflectors 14 disposed side by side. Each of the first
micro-reflectors 13 has a crest line 131, and each of the second
micro-reflectors 14 has a crest line 141. The first
micro-reflectors 13 have first average height and width which are
different from second average height and width of the second
micro-reflectors 14. The first average height of the first
micro-reflectors 13 means the average value of the perpendicular
heights of the micro-reflectors 13. The second average height of
the second micro-reflectors 14 means the average value of the
perpendicular heights of the second micro-reflectors 14. The first
average width of the first micro-reflectors 13 means the average
value of the width taken from the cross-section at the bottom of
each of the first micro-reflectors 13. The second average width of
the second micro-reflectors 14 means the average value of the width
taken from the cross-section at the bottom of each of the second
micro-reflectors 14. If the view is taken from the first side 11 of
the brightness enhancement film 1, the cross-sections of the first
micro-reflectors 13 and the second micro-reflectors 14 are in
triangular shapes, as shown in FIG. 3. Each of the first
micro-reflectors 13 and the second micro-reflectors 14 has two base
angles a and p which are same. If the view is taken from the second
side 12, the crest lines 131 and 141 of the first micro-reflector
13 and the second micro-reflector 14 are wavy, as shown in FIG. 4.
The first micro-reflector 13 has a peak 133 and a valley 132, and
the second micro-reflector 14 has a peak 143 and a valley 142. The
valley 132 of the first micro-reflector 13 has an equal height with
respect to the peak 143 of the second micro-reflector 14. The
widths of the first micro-reflector 13 and the second
micro-reflector 14 vary along with the valleys 132 and 142, and
along with the peaks 133 and 143 to broaden or to narrow with
respect to two sides thereof, as shown in FIG. 5. This forms a
neighboring line D between the first micro-reflector 13 and the
second micro-reflector 14 in a wave shape.
[0036] As shown in FIG. 6, the brightness enhancement film 1 of the
present invention is coupled with a light guide plate A1, a light
source A2, a reflector A3, and a diffusion film A4 to form a
backlight module of a LCD display. The light resource A2 is
disposed at one side of the light guide plate A1 to provide light
ray emitting into the light guide plate A1 from a ray entering side
A6. The fully reflection of the ray in the light guide plate A1
will be transferred therein, thus the reflecting ray emits from a
ray displaying side A7 through the diffusion film A4, the peaks 133
and 143 of the first micro-reflectors 13 and the second of the
micro-reflectors 14 of the brightness enhancing film 1, and out
from a LCD panel B.
[0037] Another example is that the valley 132 of the first
micro-reflector 13 may have a different height with respect to the
peak 143 of the second micro-reflector 14, which also provides the
same effect.
[0038] Another embodiment of the present invention, as shown in
FIG. 7, is substantially similar to the aforesaid embodiment with
the exceptions described hereinafter. The cross-section of each of
the first micro-reflectors 13 and the second micro-reflectors 14 of
the brightness enhancing film 1 is triangle having two different
base angles .alpha. and .beta., which also provides the same
effect.
[0039] FIG. 8 is luminosity plot of a backlight module, luminance
3240 nits without the brightness enhancement film 1 and luminance
5694 nits with the brightness enhancement film 1. The gain has an
average of 1.76 times.
* * * * *