A method for determining a wiring pattern of a conductive film, with the conductive film being adapted to be installed on a display unit of a display device and to have a wiring pattern obtained by giving irregularity to a rhomboidal wiring pattern, said wiring pattern being formed by the plurality of thin metal wires in a meshed manner and arraying a plurality of openings, comprising the steps of:
- acquiring transmittance image data of a predetermined wiring pattern and transmittance image data of a pixel array pattern of the display unit, on which pattern the predetermined wiring pattern is superimposed;
- calculating peak frequencies and peak intensities of plural spectrum peaks in a two-dimensional Fourier spectrum of the transmittance image data of the predetermined wiring pattern and peak frequencies and peak intensities of plural spectrum peaks in a two-dimensional Fourier spectrum of the transmittance image data of the pixel array pattern by performing a two-dimensional Fourier transform on the transmittance image data of the predetermined wiring pattern and the transmittance image data of the pixel array pattern;
- calculating frequency information of moire and intensity information of moire from the peak frequencies and the peak intensities of the predetermined wiring pattern and the pixel array pattern thus calculated, respectively;
- calculating frequencies of moire and intensities of moire by applying a visual response characteristic of human beings to the frequency information of moire and the intensity information of moire thus obtained;
- making comparison with respect to the frequencies of moire and the intensities of moire thus obtained such that a sum of intensities of moire each corresponding to each of frequencies of moire falling within a predetermined frequency range determined depending on the visual response characteristic is compared with a predetermined value;
- changing the transmittance image data of the predetermined wiring pattern to transmittance image data of a new wiring pattern in a case in which the sum of the intensities of moire is greater than the predetermined value, and repeating the steps of calculating the peak frequencies and the peak intensities, calculating the frequency information of moire and the intensity information of moire, calculating the frequencies of moire and the intensities of moire, and making comparison between the sum of the intensities of moire and the predetermined value until the sum of the intensities of moire is less than or equal to the predetermined value;
- setting a rhomboidal wiring pattern which causes the sum of the intensities of moire to be less than or equal to the predetermined value as the wiring pattern of the conductive film;
- and
- giving the irregularity in a predetermined range determined depending on a width of the thin metal wires to rhomboid shapes of the set rhomboidal wiring pattern, and determining a randomized wiring pattern having randomized rhomboid shapes that the irregularity is given to be the wiring pattern of the conductive film,
- wherein the frequency of moire and the intensity of moire are obtained by performing convolution with a visual transfer function as the visual response characteristic on the frequency information of moire and the intensity information of moire,
- wherein the predetermined frequency range of the frequency of moire is up to 3 cycles/mm, and
- wherein the predetermined wiring pattern undergoes ranking for optimization in a case in which it involves a frequency of moire less than or equal to 3 cycles/mm, and the predetermined wiring pattern undergoing the ranking for optimization causes the sum of intensities of moire to be less than or equal to 0 in terms of common logarithm on condition that the predetermined wiring pattern does not undergo the ranking for optimization in a case in which it involves an intensity of moire greater than or equal to −5 in terms of common logarithm at a frequency of moire less than or equal to 1.8 cycles/mm and in a case in which it involves an intensity of moire greater than or equal to −3.7 in terms of common logarithm at a frequency of moire greater than 1.8 cycles/mm but not greater than 3 cycles/mm.