Laser processing device having an optical arrangement which comprises a beam splitter

A method of interference patterning a surface, the method comprising:

• generating a first interference pattern on the surface;
• generating a second interference pattern on the surface;
• wherein the generating of the first interference pattern and the second interference pattern is performed by a single optical arrangement comprising an input including a beam splitter that splits the laser beam into at least two partial beams;
• wherein a first position P1 of a center of a laser spot, that recombines the two partial beams, and the first interference pattern are generated by the laser beam being in a first state and a second position P2 of the center of the laser spot, that recombines the two partial beams, and the second interference pattern are generated by the laser beam being in a second state, wherein a change from the first state to the second state is performed by changing a position of the laser beam at the input and/or changing an angle of incidence of the laser beam with respect to the input, and thereby causing at least one of a distance change DP and a position change DS, wherein
• (i) the distance change DP is a difference between a first distance and a second distance, wherein the first distance is between the first position P1 and the interference maximum closest to the first position P1 of the first interference pattern in a first direction that intersects an interference line of the first interference pattern and wherein the second distance is between the second position P2 and the interference maximum closest to the second position P2 of the second interference pattern in the first direction, and
• (ii) the position change DS is a difference between the first position P1 and the second position P2;
• wherein the position change DS is changed continuously by the optical arrangement during a change from the first state to the second state such that a condition
• |DS|+|DP|=n*L
• is valid, and
• wherein n is a natural number;
• wherein L is a distance in the first direction between two adjacent interference maxima of the first interference pattern or the second interference pattern, including a tolerance error range of ±5%.

A manufacturing method of objects containing interference patterned surfaces generated by emitting a laser beam on the surface of the objects, the manufacturing method including changing a position of the laser beam at an input of an optical arrangement including a beam splitter that splits the laser beam into at least two partial beams and/or changing an angle of incidence of the laser beam with respect to the input to generate a first state defining a first position P1 of a center of a laser spot, that recombines the two partial beams, and a first interference pattern, and a second state defining a second position P2 of the center of the laser spot, that recombines the two partial beams, and a second interference pattern;

• wherein
• (i) a distance change DP is a difference between a first distance and a second distance, wherein the first distance is between the first position P1 and an interference maximum closest to the first position P1 of the first interference pattern in a first direction that intersects an interference line of the first interference pattern and wherein the second distance is between the second position P2 and an interference maximum closest to the second position P2 of the second interference pattern in the first direction, and
• (ii) a position change DS is a difference between the first position P1 and the second position P2;
• wherein the position change DS is changed continuously by the optical arrangement during a change from the first state to the second state such that a condition
• |DS|+|DP|=n*L
• is valid, and
• wherein n is a natural number;
• wherein L is a distance in the first direction between two adjacent interference maxima of the first interference pattern or the second interference pattern, including a tolerance error range of ±5%.