Method for making carbon nanotube film

A method for making a carbon nanotube film, comprising:

• providing a carbon nanotube array;
• drawing an original carbon nanotube film comprising a plurality of carbon nanotubes substantially joined end-to-end by van der Waals force and oriented along a first direction from the carbon nanotube array;
• suspending the original carbon nanotube film between the carbon nanotube array and a fixing element;
• irradiating the original carbon nanotube film suspended between the carbon nanotube array and a fixing element along the first direction to form a patterned carbon nanotube film, wherein a portion of the original carbon nanotube film which is irradiated is completely removed, a plurality of through holes are formed and arranged in a plurality of rows in the first direction, each row comprises at least two spaced though holes, a shape of each of the plurality of through holes is rectangular, and each of the plurality of through holes extends along the first direction;
• a length of each through hole along the first direction is defined as parameter A, a width of each through hole in is defined as parameter B, a first space between adjacent through holes along the first direction is defined as parameter C, a second space between adjacent through holes at adjacent two rows is defined as parameter D, A ranges from 1 millimeter to 3 millimeters, B ranges from 0.1 millimeters to 1 millimeter, C ranges from 1 millimeter to 2.5 millimeters, and D range from 0.6 millimeters to 1 millimeter;
• a first ratio of the parameter B to the parameter D is less than or equal to 2, and a second ratio of the parameter A to the parameter C is greater than or equal to 0.5;
• and
• applying a solvent on the patterned carbon nanotube film suspended between the carbon nanotube array and a fixing element to shrink the suspended patterned carbon nanotube film into the carbon nanotube film comprising a plurality of spaced and parallel carbon nanotube linear units and a plurality of carbon nanotube groups, and the plurality of carbon nanotube groups are joined with the plurality of carbon nanotube linear units by van der Waals force, and a ratio of a first area of the plurality of carbon nanotubes to a second area of the plurality of through holes is less than or equal to 1:19.