Mask frame assembly for depositing thin film
A mask frame assembly includes: a mask frame; at least one mask sheet arranged on the mask frame; a plurality of first support sticks extending in a first direction; and a plurality of second support sticks extending in a second direction, wherein a mask frame transformation index is within a range from about −1000 to about +1000 based on mask frame transformation index=Σ (tensile force of first support sticks/tensile rate of first support sticks)−Σ (tensile force of second support sticks/tensile rate of second support sticks), where tensile force of respective first or second support stick is given by thickness (T)×width (W)×elastic coefficient (E)×tensile rate (δ/L 0 ), δ is a transformed amount (L f −L 0 ) corresponding to tension, L 0 is an initial length of respective first or second support stick, and L f is a final length of respective first or second support stick.
1. A mask frame assembly comprising:
a mask frame including an opening and a plurality of frames surrounding the opening;
at least one mask sheet in which a plurality of deposition holes are patterned, the at least one mask sheet being arranged on the mask frame;
a plurality of first support sticks extending in a first direction; and
a plurality of second support sticks extending in a second direction,
wherein a mask frame transformation index of the plurality of first support sticks and the plurality of second support sticks is within a range from about −1000 to about +1000 based on Equation 1 below:
Equation 1
mask frame transformation index=Σ (tensile force of a first support stick among the plurality of first support sticks/tensile rate of the first support stick) Σ (tensile force of a second support stick among the plurality of second support sticks/tensile rate of the second support stick).
2. The mask frame assembly of claim 1 , wherein each of the first support sticks includes a first stick main body and at least two protrusions protruding from two opposite edges of the first stick main body in the second direction and spaced apart from each other in the first direction, and
wherein the at least two protrusions overlap at least one of the plurality of second support sticks and a boundary area of two adjacent mask sheets.
3. The mask frame assembly of claim 1 , wherein the first direction of the mask frame corresponds to a direction in which each of the plurality of first support sticks extends, and a change in length of the mask frame in the first direction is 5 μm or less.
4. The mask frame assembly of claim 1 , wherein the second direction of the mask frame corresponds to a direction in which each of the plurality of second support sticks extends, and a change in length of the mask frame in the second direction is 5 μm or less.