背光源原理及设计

d
34
---
~120 m
~10 m
Refraction-reflection
diffusion
Total reflection
35
(p ri s (d m if le fu n se( s) r)L G P () r e f l e
36
"
ε
",
37
'
38
Diffuser ------ prism lens
θc = sin1
1 n
n1 < n2 → θ c1 > θ c 2 → L1 < L2
15
Refraction Index v.s. LGP
x1
θ c1
d 1
,
ε(x,∝f(x)g(d ) )
<
θ
<
n1
x 2
θ c2
d 2
< x
< ε
n2
16
,
1 '
θ c1
1
<
θ
2'
n1
θ c2
10
Roughness
The diffusion effect depends on the roughness of the interface of the media.
R1
R1 < R2 < R3 < R4
R2
R3
R4
11
fundamental principles--total reflection and diffusion the optical properties of the printed units the optical properties for different types of reflection units the properties of the print-less LGPs
THE THEORY AND DEVELOPMENT OF THE BACKLIGHT SYSTEM FOR LIQUID CRYSTAL DISPLAYS
Hsiuwen Chen
Senior R&D Engineer Radiant Opto-electronic Co.
1
Colo r filter L C D P C B
Bac klig ht mod
2
Section 1
I, Introduction to Fundamental Optics II,Apply Optics to LGP
Section 2
III,Applied Optics in the Construction of the Back-light Modules IV,The future of the Back-light Modules
12
Critical angles LGP
total reflection
n >1
Critical angle θ c
θc
θ'=
π
2
π
2
1
n
1
1 θ c = sin n
13
Refraction Index v.s. LGP
Refraction index↑→proper energy↑
θ1 θ2
6
The Refraction Rule of Light
In
N
n
θ
In 1, ,insert line( ),normal(
N
Rfr
)
n'
and reflect line( ) are on
θ'
Rfr
the same plane. 2,insert angle and refraction angle act= n' sinθ ' n sinθ according to the Snell's law
7
The meanings of the Snell's Law 1,if n < n'
sin θ > sin θ ' θ > θ '
0 ≤θ ≤
π
2
0 ≤ θ'<
π
2
2,if n > n'
sin θ < sin θ ' θ < θ '
0 ≤θ <
π
2
0 ≤ θ'≤
π
2
What's happened when θ ' = π ?
39
α > 90 o
α
n
n
α < 90 o
α
40
The future and challenge of Backlight modules 1,future: LCD↑BL↑ 2,challenge: (1),Brightness↑, Uniformity↑ (2), Notebookthinner and thinner Monitor larger and larger (3),EL, OLED,…..
2
8
The Critical Angle and Total Reflection = n' π When n > n' and θ ' = π sin θ = sin
2
n
2
<1
θc
n
n'
π
2
n' θ c = sin 1 Cr n iti ca θ > θ c Total l reflectio an θ < θ c Normal n gl refractio e n
23
dimension(~250m)
24
" 1, 2, 3, 4,
: "
"
"
"
"
patterns
25
26
27
V-groove type
U-groove type
28
α
π
2
α
2
α
π
2
α
2
29
θ
w
d
α
π
2
p
φ
α
2
η' ∝
w f (θ ) g (φ ) ε w+ p
θ'
n =1
n1 ; n2
sin θ 1 = n1 sin θ ' sin θ 2 = n2 sin θ '
n1 < n2 θ 1 < θ 2
14
Refraction index v.s. LGP
refraction index↑effective area of luminary↑
L2 L1
θ c2 θ c1
1,Reflection and refraction phenomena will happen on the interface when light transports through it. 2, the reflection of light acts according to the
5
2
n2
17
,
18
n ≥ n' > 1
p
p1 p4 p2 p3
n
n'
1
19
η
η ∝ c ε A
η
ε
c
20
c1 c2
c3
21
,
x ↑ ε ↓;η ( x1 ) = η ( x 2 ) x ↑ A ↑
η ( x1 ) x1 η ( x2 ) x2
ε ( x1 ) > ε ( x 2 )
41
�
The Reflection Rule of Light
In
N
Out
N In 1,insert line( ),normal( O )
θቤተ መጻሕፍቲ ባይዱ
θ'
and reflect line( ) are on the same plane. 2,insert angle θ ' θ = is equal to the reflection angle.
9
Diffusion
When parallel light waves through rough surfaces or particles, diffusion will be formed by the reason that non-parallel factor of the normal for those surfaces and particles.
θ ≥ θc φ ≤ θc
w = 2d tan
α
2
30
(pitch)
p↓
α
p↑
α
31
f (R)
η ' ∝ c ε Am
η ' ∝ f ( R ) ε Am
32
:
" ,
~ 100 m
"
,
~ 10 m
intensity
intensity 33
Parallel light Photo mask Photo resist substrate Form the metal plate by electroforming
A( x1 ) < A( x 2 )
ε ( x1 ); A( x1 )