Mask for LITI and LITI method using the same
View Patent ↗A mask for LITI and a LITI method using the same wherein the mask includes patterns arranged in a direction perpendicular to a beam scanning direction and are arranged so that increasingly longer patterns are located towards the edge of the mask than in or near the center.
1. A mask for laser induced thermal imaging (LITI), comprising patterns arranged in a direction perpendicular to a beam scanning direction, such that increasingly longer patterns are located towards the edges of the mask than in or near the center of the mask.
2. The mask according to claim 1 , wherein when each pattern has a width b, a laser beam power density h(x, y), a beam scanning direction-y, a direction x perpendicular to the beam scanning direction, and a center of the pattern in a center region (0, 0) and its length d, then the pattern centered at x=a has a length p satisfying the following equation
∫
-
d
/
2
+
d
/
2
∫
-
b
/
2
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
=
∫
-
p
/
2
+
p
/
2
∫
a
-
b
/
2
a
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
.
3. The mask according to claim 1 , wherein the patterns are used to pattern an emission layer of an organic light emitting display device.
4. The mask according to claim 1 , wherein the distance between center axes of adjacent patterns is incrementally reduced, from the center of the mask to the edges of the mask.
5. The mask according to claim 1 , wherein the distance between adjacent edges of the patterns is incrementally reduced, from the center of the mask to the edges of the mask.
6. The mask according to claim 1 , wherein when the mask is used with substrate patterns having center axes corresponding to the center axes of the patterns, misalignment between center axes of substrate patterns and the corresponding center axes of the patterns of the mask is reduced in the substrate patterns and the patterns of the mask that are located towards the edges of a substrate or the mask.
7. A laser induced thermal imaging (LITI) method using a LITI apparatus comprising an optical unit having a laser and a projection lens, and a stage placed under the optical unit, the method comprising:
disposing a mask for the LITI apparatus between the laser and the projection lens, wherein the mask comprises patterns arranged in a direction perpendicular to a beam scanning direction, such that increasingly longer patterns are located towards the edges of the mask than in or near the center of the mask; and
placing a substrate on the stage placed under the optical unit.
8. The LITI method according to claim 7 , further comprising a laser beam scanning the substrate in the beam scanning direction of the mask patterns after placing the substrate on the stage.
9. The LITI method according to claim 8 , further comprising moving the optical unit in the direction perpendicular to the scanning direction after the scanning operation, and the laser beam performing another scanning.
10. The LITI method according to claim 7 , wherein when each pattern has a width b, a laser beam power density h(x, y), a beam scanning direction-y, a direction x perpendicular to the beam scanning direction, and a center of the pattern in a center region (0, 0) and its length d, then the pattern centered at x=a in the mask has a length p satisfying the following equation:
∫
-
d
/
2
+
d
/
2
∫
-
b
/
2
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
=
∫
-
p
/
2
+
p
/
2
∫
a
-
b
/
2
a
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
.
11. The LITI method according to claim 7 , wherein the distance between center axes of adjacent patterns is incrementally reduced, from the center of the mask to the edges of the mask.
12. The LITI method according to claim 7 , further comprising placing a donor substrate having a transfer layer on the substrate.
13. The LITI method according to claim 12 , wherein the transfer layer is used as an emission layer of an organic light emitting display device.
14. A mask for use with laser induced thermal imaging (LITI) apparatus, the mask comprising:
a first pattern not located in a center of the mask; and
a second pattern located in or near the center of the mask so that the amount of light passing through the first and second patterns are equal,
wherein when each pattern has a width b, a laser beam power density h(x, y), a beam scanning direction y, a direction x perpendicular to the beam scanning direction; and a center of the second pattern in a center region (0, 0) and its length d, then the first pattern having centered at x=a in the mask has a length p satisfying the following equation:
∫
-
d
/
2
+
d
/
2
∫
-
b
/
2
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
=
∫
-
p
/
2
+
p
/
2
∫
a
-
b
/
2
a
+
b
/
2
h
(
x
,
y
)
ⅆ
x
ⅆ
y
.
15. The mask according to claim 14 , wherein the length d is shorter than length p.