Conductive mesh design method and electromagnetic shielding substrate manufacturing method

Abstract

To select a specification for satisfying a target value by considering variations due to a printing process without repeating a trial manufacture.SOLUTION: A target value is set, and a temporary mesh condition being a formation condition of a conductive mesh to be formed by a conductive wire to be printed on a transparent substrate is set. If it is determined that a mesh condition to satisfy the target value exists in a prescribed analysis simulation with the temporary mesh condition as an analysis object, a provisional specification mesh condition is selected on the basis of the temporary mesh condition of a determination object. A trail product manufactured by printing the conductive wire on the transparent substrate according to the provisional specification mesh condition, and a mesh condition of the trail production is calculated to be an actual measurement mesh condition on the basis of an actually measured result. If it is determined that a mesh condition to satisfy the target value exists in the prescribed analysis simulation with the actual measurement mesh condition as an analysis result, a final specification mesh condition is selected on the basis of the actual measurement mesh condition of a determination object and the provisional specification mesh condition.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a method for designing a conductive mesh and a method for manufacturing an electromagnetic shielding substrate. [Background technology]

[0002] There are problems such as electronic devices malfunctioning due to electromagnetic waves coming from outside, and electromagnetic waves generated from electronic devices leaking out and causing other electronic devices to malfunction. To solve these problems, techniques for shielding electromagnetic waves have been proposed (see, for example, Patent Document 1).

[0003] One technique for shielding against such electromagnetic waves is to produce an electromagnetic shielding substrate by spraying conductive ink in a mesh shape onto a transparent substrate such as glass using an inkjet method to print conductive lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-196756 Public Relations Summary of the Invention [Problem to be solved by the invention]

[0005] Shield Effectiveness (hereinafter referred to as SE) is known as an index of electromagnetic shielding performance. In the case of an electromagnetic shielding substrate containing the mesh-shaped conductive wires described above, SE varies depending on the opening size of the mesh, the thickness of the conductive wires, and the conductivity of the material used for the conductive wires.

[0006] For example, if the mesh opening size is equal to or greater than half the wavelength of the electromagnetic wave, the electromagnetic wave will be completely transmitted without being shielded. Therefore, if the mesh opening size is made shorter than half the wavelength of the electromagnetic wave to be shielded, the amount of electromagnetic wave transmitted can be reduced, resulting in an increase in SE. On the other hand, when an electromagnetic shielding substrate is used as, for example, window glass, it is necessary to transmit sufficient light to function as a window, so the mesh opening size cannot be made excessively small. Therefore, when an electromagnetic shielding substrate is used for applications such as window glass, it is necessary to set the mesh opening size so as to achieve the desired SE for electromagnetic waves of the frequency to be shielded while also achieving the desired light transmittance.

[0007] Due to the skin effect, the skin depth of a conductive wire varies depending on the frequency of the electromagnetic wave, and if the thickness of the conductive wire is smaller than the skin depth, the SE decreases. When the frequency of the electromagnetic wave to be shielded is fixed, it is ideal to set the thickness of the conductive wire to approximately the skin depth corresponding to that frequency, but the skin depth also varies depending on the conductivity of the conductive wire. Therefore, to achieve the desired SE against the electromagnetic wave of the frequency to be shielded while also achieving the ideal thickness for the conductive wire, it is necessary to find an appropriate combination of the conductive wire material and the conductive wire thickness.

[0008] For the reasons described above, when mass-producing electromagnetic shielding substrates that satisfy target values ​​such as the frequency of the electromagnetic waves to be shielded, the desired SE, and the desired light transmittance, it is necessary to select in advance as design specifications the manufacturing conditions that will satisfy these target values.

[0009] However, the cross-sectional shape of the conductive lines printed on the transparent substrate is not rectangular, but rather arched with flared bottoms. Furthermore, the state of the conductive ink sprayed onto the transparent substrate is uneven, resulting in unevenness depending on the location on the substrate. Due to these variations caused by the printing process, the actual spacing, width, thickness, and conductivity of the conductive lines do not match the specifications. Therefore, analytically calculating specifications based on target values ​​is difficult, and the general practice is to repeatedly fabricate prototypes of the electromagnetic shielding substrate, irradiate the fabricated electromagnetic shielding substrate with actual electromagnetic waves, and select specifications that satisfy the target values.

[0010] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a method for designing a conductive mesh and a method for manufacturing an electromagnetic shielding substrate that make it possible to select specifications that satisfy target values, taking into account variations caused by the printing process, without having to make repeated prototypes. [Means for solving the problem]

[0011] In order to solve the above-described problems, the conductive mesh design method according to the present disclosure includes a target value setting step of setting target values ​​including an upper limit frequency indicating an upper limit of the frequency of electromagnetic waves to be shielded, a target shielding effectiveness value indicating a target for the shielding effectiveness, and a target transmittance indicating a target for the transmittance of light; a tentative mesh condition setting step of setting tentative mesh conditions, which are mesh conditions indicating conditions for forming a conductive mesh formed by conductive lines printed on a transparent substrate and which are mesh conditions that satisfy the target values ​​within a predetermined manufacturable range; a first analysis determination step of determining whether or not there are mesh conditions that satisfy the target values ​​in a predetermined analysis simulation that uses the tentative mesh conditions as an analysis target; and a step of determining whether or not there are mesh conditions that satisfy the target values ​​in the first analysis determination step. a provisional specification mesh condition selection step of selecting provisional specification mesh conditions based on the provisional mesh conditions to be determined if it is determined that the provisional specification mesh conditions are not satisfied; a measured mesh condition calculation step of measuring a prototype produced by printing the conductive lines on the transparent substrate in accordance with the provisional specification mesh conditions and calculating the mesh conditions of the prototype based on the measurement results to set them as measured mesh conditions; a second analysis determination step of determining whether or not mesh conditions that satisfy the target value exist in the predetermined analysis simulation in which the measured mesh conditions are the analysis target; and a final specification mesh condition selection step of selecting final specification mesh conditions according to the provisional specification mesh conditions if it is determined in the second analysis determination step that mesh conditions that satisfy the target value exist.

[0012] The method for manufacturing an electromagnetic shielding substrate according to the present disclosure involves manufacturing an electromagnetic shielding substrate by printing the conductive lines on the transparent substrate in accordance with the final specification mesh conditions selected by the conductive mesh design method described above. [Effects of the Invention]

[0013] According to the disclosed conductive mesh design method and electromagnetic shielding substrate manufacturing method, it is possible to select specifications that satisfy target values, taking into account variations caused by the printing process, without having to repeatedly perform prototyping. [Brief explanation of the drawings]

[0014] [Figure 1] 1A to 1C are diagrams illustrating an example of the configuration of an electromagnetic shield substrate according to a first embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram showing a vertical cross-sectional view of an electromagnetic shield substrate according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a diagram showing a flow of a design procedure for a conductive mesh according to the first embodiment of the present disclosure. [Figure 4] FIG. 10 is a diagram (part 1) showing an example of the relationship between the characteristics of changes in the SE value, the characteristics of changes in the aperture ratio, the target SE value, and the target transmittance according to the first embodiment of the present disclosure. [Figure 5] FIG. 4 is a diagram showing a model of the cross-sectional shape of a conductive wire employed in the first analysis determination process according to the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a diagram (part 2) showing an example of the relationship between the characteristics of changes in the SE value, the characteristics of changes in the aperture ratio, the target SE value, and the target transmittance according to the first embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram showing a model of the cross-sectional shape of a conductive wire employed in the second analysis determination process according to the first embodiment of the present disclosure. [Figure 8] FIG. 10 is a diagram showing a flow of a design procedure for a conductive mesh according to a second embodiment of the present disclosure. [Figure 9] FIG. 10 is a diagram showing a vertical cross-sectional view of an electromagnetic shield substrate according to a third embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram showing a vertical cross-sectional view of an electromagnetic shield substrate according to a modified example of the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a method for designing a conductive mesh and a method for manufacturing an electromagnetic shield substrate according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 10 . FIG. 1 is a diagram illustrating an example of the configuration of an electromagnetic shield substrate 1 according to a first embodiment of the present disclosure. FIG. 2 is a diagram illustrating a vertical cross-sectional view of the electromagnetic shield substrate 1 according to the first embodiment of the present disclosure. FIG. 3 is a diagram illustrating a flow of a procedure for designing a conductive mesh according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of the relationship between a characteristic 61 of changes in SE value, a characteristic 51 of changes in aperture ratio, a target SE value, and a target transmittance according to the first embodiment of the present disclosure. FIG. 5 is a diagram illustrating a model of the cross-sectional shape of a conductive wire 20 employed in a first analysis and determination process according to the first embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of the relationship between a characteristic 62 of changes in SE value, a characteristic 51 of changes in aperture ratio, a target SE value, and a target transmittance according to the first embodiment of the present disclosure. FIG. 7 is a diagram illustrating a model of the cross-sectional shape of a conductive wire 20 employed in a second analysis and determination process according to the first embodiment of the present disclosure. FIG. 8 is a diagram illustrating a flow of a procedure for designing a conductive mesh according to a second embodiment of the present disclosure. Fig. 9 is a diagram showing a vertical cross-sectional view of an electromagnetic shield substrate 1a according to a third embodiment of the present disclosure. Fig. 10 is a diagram showing a vertical cross-sectional view of an electromagnetic shield substrate 1b according to a modified example of the third embodiment of the present disclosure. Note that the same or corresponding components in each drawing are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0016] First Embodiment (Example of electromagnetic shielding substrate configuration) FIG. 1 is a diagram showing an example of the configuration of an electromagnetic shield substrate 1 according to a first embodiment. The electromagnetic shield substrate 1 is used, for example, as window glass for vehicles, ships, aircraft, buildings, and the like. The electromagnetic shield substrate 1 includes a transparent substrate 10 and conductive wires 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3. Hereinafter, any one of the conductive wires 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 will be referred to as a conductive wire 20. The transparent substrate 10 is a transparent substrate that transmits light, such as glass or polycarbonate. The transparent substrate 10 may be a hard substrate or a flexible soft substrate such as a film or sheet.

[0017] Each of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 is printed on the transparent substrate 10 by spraying conductive ink onto the transparent substrate 10 using a printing method such as an inkjet method. The conductive ink is a conductor containing a metal material such as silver (Ag), copper (Cu), gold (Au), or aluminum (Al) and a material with binding properties such as epoxy resin. The conductive ink may contain one or more types of metal material. However, the components of the conductive ink used to print each of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 are the same. Therefore, the electrical conductivities of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 are the same and depend on the type of metal material contained in the conductive ink used for printing.

[0018] The vertical conductive lines 20v-1, 20v-2, and 20v-3 and the horizontal conductive lines 20h-1, 20h-2, and 20h-3 are printed so that they intersect perpendicularly. The printing is performed so that the distance between adjacent conductive lines 20 in the vertical conductive lines 20v-1, 20v-2, and 20v-3 and the distance between adjacent conductive lines 20 in the horizontal conductive lines 20h-1, 20h-2, and 20h-3 are all the same. The printing is also performed so that the widths of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 are all the same. As a result, a conductive mesh (hereinafter referred to as a conductive mesh) is formed on the transparent substrate 10 by the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3. In the conductive mesh, mesh regions 11-1, 11-2, 11-3, and 11-4 of the transparent substrate 10, which are surrounded in all four directions (top, bottom, left, and right) by any of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3, have square shapes of the same area.

[0019] The dashed lines shown inside conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 indicate the centers of conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3. The length between the center lines of conductive lines 20v-1 and 20v-2, indicated by reference numeral 31, is the mesh size, hereinafter referred to as mesh size 31. As described above, because mesh regions 11-1, 11-2, 11-3, and 11-4 have the same shape, mesh size 31 is a value that represents the mesh size of any one section of the conductive mesh.

[0020] The length indicated by the reference numeral 32 is the width of the conductive line 20v-1, hereinafter referred to as line width 32. As described above, the widths of the conductive lines 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 are the same, so line width 32 is a value representing the width of any conductive line 20 forming the conductive mesh. Note that the length of an opening in one section of the conductive mesh indicated by the reference numeral 41, obtained by subtracting line width 32 from mesh size 31, is defined as the maximum opening size of the conductive mesh, hereinafter referred to as maximum opening size 41.

[0021] Figure 2 is a vertical cross-sectional view of the electromagnetic shield substrate 1 shown in Figure 1 taken along the dashed line indicated by reference numeral 43. The length indicated by reference numeral 33 is the height, i.e., thickness, of the conductive wires 20v-1, 20v-2, and 20v-3, hereinafter referred to as wire thickness 33. The conductive wires 20v-1, 20v-2, 20v-3, 20h-1, 20h-2, and 20h-3 are printed so that they all have the same height. Therefore, wire thickness 33 represents the thickness of any conductive wire 20 that forms the conductive mesh.

[0022] Therefore, the formation conditions for the conductive mesh formed on the electromagnetic shielding substrate 1 can be expressed by four parameters: mesh size 31, line width 32, line thickness 33, and conductivity. The formation conditions for the conductive mesh expressed by these four parameters will be referred to as mesh conditions hereinafter. Note that while Fig. 1 shows an example in which three conductive wires 20 are printed in each of the vertical and horizontal directions, the number of conductive wires 20 may be any number as long as two or more conductive wires 20 are printed in each of the vertical and horizontal directions.

[0023] (Design procedure of the conductive mesh of the first embodiment) The ideal state for each of the mesh conditions of the conductive mesh formed on the electromagnetic shielding substrate 1, namely, mesh size 31, line width 32, line thickness 33, and conductivity, is to have uniform values ​​throughout the conductive mesh. However, when the conductive lines 20 are actually printed on the transparent substrate 10, variations occur due to the printing process. These variations result in variations in the position, width, thickness, and conductivity of the conductive lines 20.

[0024] The cross-sectional shape of the conductive wire 20 is ideally rectangular, but because the conductive wire 20 is formed by spraying conductive ink, it actually has a wide, arched shape as shown in Figure 2. Furthermore, because there is variation in the width and thickness of the conductive wire 20, not all conductive wires 20 have the same arched shape. Furthermore, because the state of the conductive ink sprayed onto the transparent substrate 10 is not uniform, the actual conductivity of the conductive wire 20 may not match the standard conductivity of the metal material contained in the conductive ink depending on the location on the transparent substrate 10.

[0025] The design procedure for the conductive mesh shown in FIG. 3 is a procedure for selecting design specifications to be used when manufacturing the electromagnetic shield substrate 1, taking into consideration the variations caused by the printing process as described above.

[0026] When manufacturing the electromagnetic shielding substrate 1, it is necessary to determine in advance, as target values, the upper limit of the frequency of the electromagnetic waves shielded by the electromagnetic shielding substrate 1 (hereinafter referred to as the upper limit frequency), the SE value of the electromagnetic shielding substrate 1, and the transmittance of light passing through the electromagnetic shielding substrate 1. Here, the unit of the upper limit frequency is "Hz," the unit of the SE value is "dB," and the unit of the transmittance is "%." Furthermore, the target SE value is hereinafter referred to as the target SE value, and the target transmittance is hereinafter referred to as the target transmittance.

[0027] For example, the designer sets three target values, namely, upper limit frequency, target SE value, and target transmittance, as follows (S1: target value setting step). If the objective is to shield electromagnetic waves coming from outside, the designer sets the target SE value in accordance with standards related to shielding effectiveness. On the other hand, if the objective is to prevent electromagnetic waves generated by a certain device from leaking to the outside, the designer sets the target SE value taking into consideration the signal strength of the device and the signal strength when it exits to the outside through the electromagnetic shield substrate 1.

[0028] The smaller the mesh size 31, the larger the SE value, but there is a manufacturable range of mesh size 31 depending on the performance of the printing device. Therefore, the designer sets an upper limit frequency that satisfies the set target SE value while taking into account the manufacturable range of mesh size 31. Note that if there are circumstances in which it is desired to shield a specific frequency of electromagnetic waves arriving from outside or a specific frequency of electromagnetic waves generated by a certain device, the designer may set the frequency to be shielded as the upper limit frequency without considering the set target SE value.

[0029] Regarding the target transmittance, for example, if the electromagnetic shielding substrate 1 is intended to be used as window glass, the designer sets a target transmittance that will allow the electromagnetic shielding substrate 1 to function as a window.

[0030] The designer provisionally sets four parameters of the mesh conditions that satisfy the three target values ​​set in step S1 within a manufacturable range according to the performance of the printing device used to print the conductive wire 20 (S2: provisional mesh condition setting step) as follows. Here, satisfying the target values ​​means achieving values ​​at least equal to or greater than the target values. The characteristics of the change in the aperture ratio of the conductive mesh when one of the mesh size 31, line width 32, and line thickness 33 is a variable and the remaining three are fixed can be calculated analytically. For example, when the characteristics of the change in aperture ratio when the mesh size 31 is changed while the line width 32 and line thickness 33 are fixed are calculated analytically, the result is shown by the dashed line graph 51 in FIG. 4 (hereinafter referred to as graph 51). In FIG. 4, the horizontal axis represents the mesh size 31, and the vertical axis represents the aperture ratio in graph 51.

[0031] It is possible to calculate the characteristics of the change in the SE value when one of the mesh size 31, line width 32, line thickness 33, and conductivity is a variable and the remaining three are fixed values ​​by analytical calculation using an empirical formula. For example, when the frequency of the electromagnetic wave is set to the upper frequency limit and the line width 32, line thickness 33, and conductivity are fixed values, if the characteristics of the change in the SE value when the mesh size 31 is changed are calculated by analytical calculation, the result will be like the solid line graph indicated by reference numeral 61 in Figure 4 (hereinafter referred to as graph 61). In the case of graph 61, the vertical axis of Figure 4 represents the SE value.

[0032] The mesh size 31, line width 32, and line thickness 33 each have a manufacturable range that depends on the performance of the printing device. Therefore, the designer temporarily sets a median value that is the middle of the maximum and minimum values ​​of the manufacturable range for each of the line width 32 and line thickness 33, so that fine adjustments can be made after the provisional setting. The designer temporarily sets the conductivity, for example, the conductivity of a metal material with medium conductivity, whose conductivity can be changed after the provisional setting.

[0033] The designer calculates graphs 51 and 61 with the mesh size 31 as a variable, while fixing the provisionally set line width 32, line thickness 33, and conductivity. The frequency of the electromagnetic waves used to calculate graph 61 is the upper limit frequency. Here, since the transmittance of the conductive mesh corresponds to the aperture ratio of the conductive mesh, the designer specifies a range of mesh sizes 31 in graph 51 that are equal to or greater than the target transmittance. In the case of FIG. 4 , the range of mesh sizes 31 that are equal to or greater than the target transmittance is the range in which the mesh size 31 at the intersection 56 of graph 51 and dashed line 55 representing the target transmittance is the minimum value. The designer specifies a range of mesh sizes 31 in graph 61 that are equal to or greater than the target SE value. In the case of FIG. 4 , the range of mesh sizes 31 that are equal to or greater than the target SE value is the range in which the mesh size 31 at the intersection 66 of graph 61 and dashed line 65 representing the target SE value is the maximum value.

[0034] Therefore, the range of mesh size 31 that satisfies both the target transmittance and the target SE value is the range between perpendicular line 71 passing through intersection point 56 and perpendicular line 72 passing through intersection point 66, i.e., the range indicated by reference numeral 80. The designer may provisionally set, for example, any one value within the range indicated by reference numeral 80 that is included in the manufacturable range of mesh size 31 as mesh size 31. If the entire range indicated by reference numeral 80 is included in the manufacturable range of mesh size 31, the designer may provisionally set, for example, the median value of the range indicated by reference numeral 80 as mesh size 31.

[0035] In the above procedure, the line width 32, the line thickness 33, and the conductivity are temporarily set, and then the characteristics of the change in the aperture ratio and the change in the SE value corresponding to the mesh size 31 are calculated to temporarily set the mesh size 31. Alternatively, for example, when the designer sets an upper limit frequency that satisfies the target SE value in step S1, as described above, the designer may temporarily set the mesh size 31 taking this into consideration. In this case, the designer may fix the mesh size 31, the line thickness 33, and the conductivity to their provisionally set values, calculate the characteristics of the change in the aperture ratio and the change in the SE value corresponding to the line width 32, and temporarily set the line width 32. Alternatively, the designer may first provisionally set the mesh size 31, the line width 32, and the conductivity, and then calculate the characteristics of the change in the aperture ratio and the change in the SE value corresponding to the line thickness 33 to temporarily set the line thickness 33. Hereinafter, the mesh conditions provisionally set in step S2 are referred to as provisional mesh conditions.

[0036] The characteristics of the change in the SE value calculated in step S2 are calculated by analytical calculation using an empirical formula. The accuracy of the characteristics of the change in the SE value obtained by this empirical formula is equivalent to the conductivity per unit area, and does not take into account the cross-sectional shape of the conductive mesh, resulting in an error of about 10 dB. Therefore, the designer performs a first analytical judgment process (S3: first analytical judgment step) to obtain mesh conditions that are more accurate than the provisional mesh conditions, taking into account the cross-sectional shape of the conductive mesh.

[0037] In step S3, the designer performs an electromagnetic field analysis simulation by providing, for example, the target values ​​set in step S1 and the provisional mesh conditions set in step S2 as input information to a computer capable of performing the electromagnetic field analysis simulation (S3-1). Here, the electromagnetic field analysis simulation is a simulation that evaluates the shielding effect based on the amount of electromagnetic wave transmission with and without a conductive mesh.

[0038] As shown in FIG. 2, the cross-sectional shape of the conductive wire 20 is actually an arched shape with a flared base. However, in the electromagnetic field analysis simulation, as shown in FIG. 5, the cross-sectional shape of the conductive wire 20 is modeled as a rectangle having a width of 32 and a height of 33. In the electromagnetic field analysis simulation, for example, the following simulation is performed: One parameter is selected from four parameters of the provisional mesh conditions. The other three parameters are fixed to the values ​​of the provisional mesh conditions, and the frequency of the electromagnetic waves is set to the upper limit frequency. A simulation is performed in which the value of the selected parameter is increased or decreased within a predetermined range. This simulation is performed for each of the four parameters.

[0039] As a result, the characteristics of the change in the SE value corresponding to each of the mesh size 31, wire width 32, wire thickness 33, and conductivity are obtained, and the characteristics of the change in the SE value when the frequency of the electromagnetic wave is set as the upper limit frequency. The accuracy of the characteristics of the change in the SE value obtained by the electromagnetic field analysis simulation is higher than the accuracy of the characteristics of the change in the SE value calculated by analytical calculation using an empirical formula in step S2, because the cross-sectional shape of the conductive wire 20 is taken into consideration.

[0040] As explained in the procedure of S2, it is possible to calculate in advance by analytical calculation the characteristics of the change in the aperture ratio when one of the mesh size 31, line width 32, and line thickness 33 is set as a variable and the remaining three are fixed to the values ​​of the temporary mesh conditions. Therefore, the designer calculates the characteristics of the change in the aperture ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 by analytical calculation.

[0041] The designer determines whether or not there are mesh conditions that satisfy the target values ​​based on the characteristics of the change in aperture ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 calculated by analytical calculation, the characteristics of the change in SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity obtained in the procedure of S3-1, the target transmittance, and the target SE value (S3-2).

[0042] Assume that the characteristics of the change in the SE value corresponding to the mesh size 31, the characteristics of the change in the aperture ratio, the target SE value, and the target transmittance have the relationship shown in FIG. 4, for example. In this case, there exists a range of the mesh size 31 that satisfies both the target SE value and the target transmittance, corresponding to the range indicated by reference numeral 80 in FIG. 4. Therefore, if this range overlaps with the manufacturable range of the mesh size 31, the designer determines that the mesh size 31 satisfies the target value. On the other hand, if this range does not overlap with the manufacturable range of the mesh size 31, the designer determines that the mesh size 31 does not satisfy the target value.

[0043] In contrast, suppose the characteristic of the change in the SE value corresponding to mesh size 31 is, for example, a characteristic like graph 62 shown in FIG. 6 , and the characteristic of the change in the aperture ratio corresponding to mesh size 31 is a characteristic like graph 51. In this case, the range of mesh sizes 31 that are equal to or greater than the target SE value is the range in which the mesh size 31 has a maximum value at the intersection 67 between graph 62 and the dashed-dotted line 65 indicating the target SE value. In other words, the range to the left of perpendicular line 73 passing through intersection 67 is the range of mesh sizes 31 that are equal to or greater than the target SE value. The range of mesh sizes 31 that are equal to or greater than the target transmittance is the range to the right of perpendicular line 71 passing through intersection 56, as in the case of FIG. 4 . Therefore, unlike the case of FIG. 4 , in the case of FIG. 6 , there is no range of mesh sizes 31 that satisfies both the target transmittance and the target SE value. Therefore, in the case of FIG. 6 , the designer determines that the mesh size 31 does not satisfy the target values.

[0044] As in the case of mesh size 31, the designer determines whether or not each of line width 32 and line thickness 33 satisfies the target value based on the characteristics of the change in the corresponding SE value, the characteristics of the change in the aperture ratio, the target SE value, and the target transmittance.

[0045] For conductivity, there is no characteristic for the change in aperture ratio. Therefore, the designer specifies a range in which the SE value corresponding to conductivity is equal to or greater than the target SE value based on the characteristic for the change in SE value corresponding to conductivity and the target SE value. If there is an overlap between the specified range and the manufacturable range of conductivity, the designer determines that the target value is met. If there is no overlapping range, the designer determines that the target value is not met. Here, the manufacturable range of conductivity is a range determined by the conductivity of the metal material contained in the available conductive ink.

[0046] If the target values ​​are satisfied for all of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​exist (S3-2, Yes). On the other hand, if the target values ​​are not satisfied for any of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​do not exist (S3-2, No). If the determination in step S3-2 is "No," the designer resets the tentative mesh conditions (S4: first mesh condition resetting step) and repeats step S3-1.

[0047] If the determination in step S3-2 is "Yes," the designer selects provisional specification mesh conditions that will serve as provisional specifications from the range of mesh conditions that satisfy the target values ​​(S5). For example, the designer selects the median value of the range of mesh sizes 31 that satisfy both the target SE value and the target transmittance, and the manufacturable range of mesh sizes 31, as the provisional specification mesh size 31. The designer selects each of the provisional specification line width 32 and line thickness 33 using the same procedure as for mesh size 31. The designer selects the conductivity of an available conductive ink that is near the center of the range of conductivity that satisfies the target SE value and the manufacturable range of conductivity that overlaps, as the provisional specification conductivity.

[0048] The designer sets the mesh size 31, line width 32, and line thickness 33 of the selected provisional specification mesh conditions in the printing device. The designer then sprays conductive ink having a conductivity that matches the conductivity of the provisional specification mesh conditions onto the transparent substrate 10 using the printing device, thereby printing conductive lines 20 on the transparent substrate 10 to create a prototype (S6).

[0049] The designer measures the prototype and calculates the actual mesh conditions for the prototype. The designer measures the opening size of several of the multiple compartments of the conductive mesh of the prototype. Note that, taking into account that the shape of the compartment may not be square due to variations caused by the printing process, the designer measures the opening size in the vertical and horizontal directions at several points in one compartment. The designer determines the maximum opening size of that compartment to be the largest of the opening sizes measured at several points in the compartment. The designer calculates the average value of the maximum opening sizes of several of the multiple compartments of the conductive mesh of the prototype, and determines the calculated average value as the maximum opening size 41 that represents the prototype.

[0050] As described above, the cross-sectional shape of the conductive wire 20 is an arched shape with a flared base, as shown in Fig. 7. For this reason, the designer determines multiple measurement locations in advance and calculates a mesh size 31, line width 32, and line thickness 33 that represent the prototype as follows. Note that in the case of the inkjet method, the cross-sectional shapes of the vertical conductive wires 20 differ from those of the horizontal conductive wires 20, so the multiple predetermined measurement locations should include the locations of the vertical conductive wires 20, the locations of the horizontal conductive wires 20, and the locations where the vertical and horizontal conductive wires 20 intersect.

[0051] The designer obtains data showing the cross-sectional shape of the conductive wire 20 at a plurality of measured locations of the prototype conductive wire 20. For example, the designer obtains data showing the cross-sectional shape of the conductive wire 20 by irradiating the conductive wire 20 at a plurality of measured locations with a laser using a cross-section scanner or the like. At the location where the vertical and horizontal conductive wires 20 intersect, indicated by reference numeral 42 in FIG. 1, the designer obtains data showing the cross-sectional shape of the conductive wire 20 by scanning from diagonal to diagonal as indicated by the dashed line of reference numeral 42, for example.

[0052] From the data showing the cross-sectional shape of the conductive wire 20 obtained at each of the multiple measurement points, the designer calculates the width of the conductive wire 20 at the position where the height 36 of the conductive wire 20 is half, i.e., the half-width 38, as shown in FIG. 7. Note that for the location where the conductive wires 20 intersect, indicated by reference numeral 42 in FIG. 1, the length of the half-width calculated from the data showing the cross-sectional shape of the conductive wire 20 is the length on the diagonal of the area where the vertical and horizontal conductive wires 20 intersect. Therefore, the calculated half-width is doubled. 1 / 2 The value obtained by dividing by this is the half-width 38.

[0053] The designer calculates the average value of the half-widths 38 calculated at each of the multiple measured locations, and sets the calculated average value as the line width 32. The designer sets the mesh size 31 to the sum of the line width 32 and the maximum opening size 41. The designer calculates half the height 36 of the conductive wire 20, i.e., half-height 37, from data indicating the cross-sectional shape of the conductive wire 20 obtained at each of the multiple measured locations. The designer calculates the average value of the multiple calculated half-heights 37, and sets the calculated average value as the wire thickness 33.

[0054] The designer measures the sheet resistance at multiple measurement locations on the prototype. The designer calculates the sheet resistance of the prototype through analytical calculations based on the provisional specification mesh conditions selected in step S5. Because conductivity and sheet resistance are proportional to each other, the designer calculates the ratio between the average value of the sheet resistances measured at multiple measurement locations and the calculated sheet resistance. The designer calculates a conductivity representative of the prototype based on the calculated ratio and the conductivity of the provisional specification mesh conditions. This results in the actual mesh conditions of the prototype (hereinafter referred to as measured mesh conditions) being obtained (S7: measured mesh condition calculation step).

[0055] The designer performs a second analysis judgment process to determine whether the measured mesh conditions satisfy the target values ​​(S8: second analysis judgment step). The second analysis judgment process is the same as the first analysis judgment process in step S3, but for the measured mesh conditions. Therefore, steps S8-1 and S8-2 are performed in which the tentative mesh conditions are replaced with the measured mesh conditions in steps S3-1 and S3-2, respectively.

[0056] In the procedure of S8-2, if any of the mesh size 31, line width 32, line thickness 33, and conductivity included in the measured mesh conditions does not satisfy the target value, the designer determines that there are no mesh conditions that satisfy the target value (S8-2, No). In this case, the designer resets the measured mesh conditions (S9: second mesh condition resetting step) and performs the procedure of S8-1 again.

[0057] In step S8-2, if the target values ​​are satisfied for all of the mesh size 31, wire width 32, wire thickness 33, and conductivity included in the measured mesh conditions, the designer determines that mesh conditions that satisfy the target values ​​exist (S8-2, Yes). Here, it is assumed that the step of resetting the measured mesh conditions in step S9 has never been performed, in other words, the measured mesh conditions calculated in step S7 and the measured mesh conditions to be determined in step S8-2 are the same. In this case, the designer selects the provisional specification mesh conditions selected in step S5 as the mesh conditions for the final specifications (hereinafter referred to as final specification mesh conditions).

[0058] On the other hand, if the procedure S9 is being performed, in other words, if the measured mesh conditions calculated in the procedure S7 differ from the measured mesh conditions to be determined in the procedure S8-2, the designer selects the final specification mesh conditions as follows. The designer calculates the ratio of difference between the last reset measured mesh conditions and the measured mesh conditions calculated in the procedure S7. More specifically, the designer calculates the ratio of difference between the mesh size 31, the wire width 32, the wire thickness 33, and the conductivity included in the two measured mesh conditions. The measured mesh conditions calculated in the procedure S7 are the mesh conditions of a prototype produced in accordance with the provisional specification mesh conditions selected in the procedure S5. Therefore, the designer applies the corresponding ratio of difference to each of the four parameters of the provisional specification mesh conditions selected in the procedure S5, thereby correcting the values ​​of the four parameters of the provisional specification mesh conditions so that they correspond to the values ​​of the four parameters of the last reset measured mesh conditions. The designer selects the corrected provisional specification mesh conditions as the final specification mesh conditions (S10: final specification mesh condition selection step).

[0059] (Advantages of the first embodiment) In the design procedure for the conductive mesh of the first embodiment, target values ​​for the electromagnetic shielding substrate 1 are set, and then provisional mesh conditions are set based on the manufacturable range and the results of analytical calculations. By performing an electromagnetic field analysis simulation using the provisional mesh conditions as the analysis target, it is possible to obtain characteristics of changes in the SE value with higher accuracy than analytical calculations, making it possible to select provisional specification mesh conditions with higher accuracy than the provisional mesh conditions. A prototype is fabricated according to the selected provisional specification mesh conditions, and the mesh conditions of the fabricated prototype are calculated based on the actual measurement results of the prototype, thereby obtaining the measured mesh conditions, which are the actual mesh conditions corresponding to the provisional specification mesh conditions. Differences between the provisional specification mesh conditions and the measured mesh conditions indicate variations due to the printing process. An electromagnetic field analysis simulation is performed using the measured mesh conditions as the analysis target, and the measured mesh conditions are corrected based on the results of the electromagnetic field analysis simulation to satisfy the target values. Furthermore, the corresponding corrections are applied to the provisional specification mesh conditions. This makes it possible to select final specification mesh conditions that take into account variations due to the printing process. By manufacturing according to the final specification mesh conditions, it is possible to obtain an electromagnetic shielding substrate 1 that has shielding performance that satisfies the target SE value for electromagnetic waves at the upper limit frequency, as well as optical performance that satisfies the target transmittance.

[0060] As described above, the design procedure for the conductive mesh according to the first embodiment allows for the selection of mesh condition specifications that satisfy the target values ​​while taking into account variations due to the printing process, without the need for repeated prototyping, and without irradiating the prototype with actual electromagnetic waves. Therefore, even if variations due to the printing process are at their worst, it is possible to manufacture an electromagnetic shielding substrate 1 that at least satisfies the target values.

[0061] The actual shape of the conductive wire 20 formed by printing the conductive ink is a curved shape with a flared base. In contrast, in the first embodiment described above, when calculating the actual mesh conditions based on the measured values ​​of a prototype in step S7, the average value of the half-width 38 of the conductive wire 20 is set to the wire width 32, and the average value of the half-height 37 of the conductive wire 20 is set to the wire thickness 33. Furthermore, in the electromagnetic field analysis simulation in step S8-1 of FIG. 3, the cross-sectional shape of the conductive wire 20 is modeled as a rectangle with a height equal to the wire thickness 33 and a width equal to the wire width 32, rather than the original complex shape. By performing such modeling, in the first embodiment, the number of parameters representing the cross-sectional shape of the conductive wire 20 is reduced, thereby reducing the load of the electromagnetic field analysis simulation process, and it is possible to obtain characteristics of changes in the SE value with sufficient accuracy that is acceptable for selecting the final specification mesh conditions.

[0062] In the first embodiment described above, in step S7, the sheet resistance is measured at multiple measurement locations on the prototype, and the conductivity of the prototype conductive wire 20 is calculated from the average of the measured sheet resistances. The calculated conductivity is then used in step S8 as the conductivity representative of the prototype. Therefore, the characteristics of the SE value change obtained in step S8-1 reflect the conductivity based on the measured sheet resistance. As a result, in step S10, a final specification mesh condition is obtained in which the combination of wire thickness 33 and conductivity is an appropriate combination that takes skin depth into consideration.

[0063] <Second embodiment> For example, if the upper limit frequency set as the target value is 1 GHz, the wavelength is approximately 30 cm. As described above, if the maximum opening size 41 of the conductive mesh is equal to or greater than half the wavelength of the electromagnetic wave, the electromagnetic wave will be completely transmitted. Therefore, to shield 1 GHz electromagnetic waves, the maximum opening size 41 of one section must be smaller than 15 cm. In contrast, since the wavelength of visible light is on the order of nanometers, an electromagnetic shielding substrate manufactured for shielding electromagnetic waves of approximately 1 GHz theoretically allows all visible light to pass through. However, in reality, depending on the printing condition, bleeding or distortion of the conductive wire 20 may occur, causing diffuse reflection and scattering when visible light passes through, or it may bend rather than pass straight through. Therefore, when the electromagnetic shielding substrate 1 manufactured according to the final specification mesh conditions obtained by the first embodiment is visually inspected or the electromagnetic shielding substrate 1 is placed in front of a camera's imaging element to check visibility, the desired visibility performance may not be satisfied.

[0064] (Design procedure of conductive mesh in the second embodiment) In the first embodiment, the elements to be considered from an optical perspective were the characteristics of the change in aperture ratio corresponding to each of mesh size 31, line width 32, and line thickness 33 calculated by analytical calculation, and the target transmittance. In contrast, in the second embodiment, in addition to the transmittance, the haze ratio is set as a target value, and optical analysis simulation is further employed to select final specification mesh conditions for manufacturing an electromagnetic shielding substrate 1 that achieves the desired visibility performance.

[0065] 8 shows the procedure for selecting design specifications to be used when manufacturing the electromagnetic shielding substrate 1 according to the second embodiment. The configuration of the electromagnetic shielding substrate 1 according to the second embodiment is the same as that of the electromagnetic shielding substrate 1 according to the first embodiment shown in FIG.

[0066] As in the first embodiment, the designer sets an upper limit frequency, a target transmittance, and a target SE value as target values. In the second embodiment, the designer also sets a desired haze ratio as a target value. Hereinafter, the target haze ratio will be referred to as the target haze ratio (Sa1: target value setting step). Hereinafter, the haze ratio is an index representing the degree of light scattering, and is expressed in units of "%." A high haze ratio means, for example, that there is a lot of light scattering inside the transparent substrate 10, resulting in reduced transparency and a cloudy transparent substrate 10. In other words, in the second embodiment, whether the visibility of the electromagnetic shielding substrate 1, in which conductive lines 20 are printed on the transparent substrate 10, is the desired visibility is determined based on the target transmittance and the target haze ratio.

[0067] The designer sets tentative mesh conditions using the same procedure as S2 in the first embodiment (Sa2: tentative mesh condition setting step). The designer performs the first analysis determination process in the second embodiment (Sa3: first analysis determination step). In step Sa3-1 of the first analysis determination process in the second embodiment, an electromagnetic field analysis simulation process is performed using the same tentative mesh conditions as the first analysis determination process in the first embodiment as the analysis target. In step Sa3-1, an optical analysis simulation process is also performed using the tentative mesh conditions as the analysis target.

[0068] For example, a designer performs an optical analysis simulation by providing the target values ​​set in step Sa1 and the provisional mesh conditions set in step Sa2 as input information to a computer capable of performing the optical analysis simulation (Sa3-1). Here, the optical analysis simulation is a simulation that uses a technique such as ray tracing.

[0069] As shown in FIG. 2, the cross-sectional shape of the conductive wire 20 is actually a curved arch with a flared base. However, in the optical analysis simulation in step Sa3-1, as shown in FIG. 5, the cross-sectional shape of the conductive wire 20 is modeled as a rectangle having a width of 32 and a height of 33. In the optical analysis simulation, for example, the following simulation is performed: One parameter, excluding conductivity, is selected from the four parameters of the provisional mesh conditions. A simulation is performed in which the value of the selected parameter is increased or decreased within a predetermined range while the other three parameters are fixed to the values ​​of the provisional mesh conditions. As a result of the optical analysis simulation, the characteristics of the change in aperture ratio and the change in haze ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 are obtained.

[0070] The designer determines whether or not there are mesh conditions that satisfy the target values ​​based on the characteristics of the change in opening ratio and the characteristics of the change in haze ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 obtained by the procedure Sa3-1, the characteristics of the change in SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity obtained by the procedure Sa3-1, the target transmittance, the target haze ratio, and the target SE value, using a procedure similar to S3-2 in the first embodiment (Sa3-2).

[0071] For example, in the case of mesh size 31, the characteristics of the change in the opening ratio, the characteristics of the change in the haze ratio, and the characteristics of the change in the SE value corresponding to mesh size 31 are each shown in graphs such as those shown in Figures 4 and 6. In the graphs showing the three characteristics, the characteristics of the change in the opening ratio and the range of mesh sizes 31 that satisfy the target transmittance specified by the target transmittance are specified, the characteristics of the change in the haze ratio and the range of mesh sizes 31 that satisfy the target haze ratio specified by the target haze ratio, and the characteristics of the change in the SE value and the range of mesh sizes 31 that satisfy the target SE value specified by the target SE value are specified.

[0072] If there is an overlapping range among the four ranges, which is the three ranges plus the manufacturable range of mesh size 31, the designer determines that mesh size 31 satisfies the target value. On the other hand, if there is no overlapping range among the four ranges, the designer determines that mesh size 31 satisfies the target value. As with mesh size 31, the designer also determines whether each of line width 32 and line thickness 33 satisfies the target value. Note that with regard to conductivity, because there is no characteristic for the change in aperture ratio or the change in haze ratio, whether or not the target value is satisfied is determined using the same procedure as S3-2 in the first embodiment.

[0073] If the target values ​​are satisfied for all of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​exist (Sa3-2, Yes). On the other hand, if the target values ​​are not satisfied for any of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​do not exist (Sa3-2, No). If the determination in step Sa3-2 is "No," the designer resets the tentative mesh conditions (Sa4: first mesh condition resetting step) and performs step Sa3-1 again.

[0074] If the determination in step Sa3-2 is "Yes," the designer selects provisional specification mesh conditions that will serve as provisional specifications from the range of mesh conditions that satisfy the target values ​​(Sa5). For example, the designer selects the median value of the range of mesh sizes 31 that satisfy all of the target SE value, target transmittance, and target haze ratio, and the manufacturable range of mesh sizes 31, as the provisional specification mesh size 31. The designer selects each of the provisional specification line width 32 and line thickness 33 using the same procedure as for the mesh size 31. The designer selects the conductivity of an available conductive ink that is near the center of the range of conductivity that satisfies the target SE value and the manufacturable range of conductivity that overlaps, as the provisional specification conductivity.

[0075] Using the same procedure as S6 in the first embodiment, the designer creates a prototype in accordance with the provisional specification mesh conditions (Sa6). Using the same procedure as S7 in the first embodiment, the designer calculates the maximum opening size 41 and conductivity of the prototype. As with the procedure of S7 in the first embodiment, the designer measures the height 36 of the conductive wires 20 at each of multiple measurement locations on the prototype, calculates the half-height 37 and half-width 38, and further measures the width 39 of the conductive wires 20. Note that, at the locations where the conductive wires 20 intersect, indicated by reference numeral 42 in FIG. 1, the measured width is the length on the diagonal of the region where the vertical and horizontal conductive wires 20 intersect. Therefore, the measured width is doubled. 1 / 2 The value divided by this is set to width 39.

[0076] The designer calculates first measured mesh conditions, which are measured mesh conditions for the electromagnetic field analysis simulation, and second measured mesh conditions, which are measured mesh conditions for the optical analysis simulation, as follows: For the first measured mesh conditions, the designer sets wire thickness 33 to the average value of half-height 37 of conductive wire 20, wire width 32 to the average value of half-width 38 of conductive wire 20, mesh size 31 to the value obtained by adding maximum opening size 41 to wire width 32, and conductivity to the calculated conductivity. That is, the first measured mesh conditions are calculated using the same procedure as the measured mesh conditions calculated in step S7 of the first embodiment.

[0077] As the second measured mesh condition, the designer sets the wire thickness 33 to the average value of the height 36 of the conductive wire 20, the wire width 32 to the average value of the width 39 of the conductive wire 20, the mesh size 31 to the maximum opening size 41 plus the wire width 32, and the conductivity to the calculated conductivity (Sa7-1: measured mesh condition calculation step).

[0078] The designer irradiates the prototype with visible light, receives the visible light that passes through the prototype using a sensor or the like, and measures the transmittance and haze ratio of the prototype (Sa7-2: transmittance measurement step, haze ratio measurement step).

[0079] The designer performs a second analysis judgment process to determine whether the measured mesh conditions satisfy the target values ​​(Sa8: second analysis judgment step). As a procedure Sa8-1 of the second analysis judgment process of the second embodiment, an electromagnetic field analysis simulation is performed in which the provisional mesh conditions are replaced with the first measured mesh conditions in the procedure Sa3-1, and an optical analysis simulation is performed in which the provisional mesh conditions are replaced with the second measured mesh conditions.

[0080] In other words, in step Sa8-1, the electromagnetic field analysis simulation is performed in the same manner as step S8-1 in the first embodiment. That is, the electromagnetic field analysis simulation is performed in which the cross-sectional shape of conductive wire 20 is modeled as a rectangular shape specified by the average value of half-height 37 of conductive wire 20 and the average value of half-width 38 of conductive wire 20. In contrast, the optical analysis simulation in step Sa8-1 is performed in which the cross-sectional shape of conductive wire 20 is modeled as a rectangular shape specified by the average value of width 39 of conductive wire 20 and the average value of height 36 of conductive wire 20.

[0081] The reason why the electromagnetic field analysis simulation and the optical analysis simulation use different models for the cross-sectional shape of the conductive wire 20 is as follows: The electromagnetic field analysis simulation targets electromagnetic waves of about 1 GHz, while the optical analysis simulation targets visible light, and the wavelengths of the electromagnetic waves targeted are significantly different. Because the wavelength of visible light is on the order of nanometers, even a small change in the cross-sectional shape of the conductive wire 20 significantly changes the degree of phenomena such as transmission and scattering. Therefore, in order to obtain highly accurate results in the optical analysis simulation, it is necessary to analyze the actual height and width of the conductive wire 20.

[0082] The electromagnetic field analysis simulation in the procedure Sa8-1 obtains the characteristics of the change in the SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity. In addition, the optical analysis simulation in the procedure Sa8-1 obtains the characteristics of the change in the aperture ratio and the characteristics of the change in the haze ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 (Sa8-1).

[0083] The designer corrects the characteristics of the change in the aperture ratio corresponding to mesh size 31 obtained in step Sa8-1 so that the characteristics become the transmittance of the prototype measured in step Sa7-2 at the position of mesh size 31 under the second measured mesh condition. This correction is performed, for example, by multiplying a coefficient by a function that approximates the characteristics of the change in the aperture ratio corresponding to mesh size 31 obtained in step Sa8-1. Similarly, the designer corrects the characteristics of the change in the aperture ratio corresponding to each of line width 32 and line thickness 33 based on the second measured mesh condition and the transmittance of the prototype measured.

[0084] The designer corrects the characteristics of the change in haze ratio corresponding to mesh size 31 obtained in step Sa8-1 so that the haze ratio becomes the same as the haze ratio of the prototype measured in step Sa7-2 at the position of mesh size 31 under the second measurement mesh conditions. This correction is performed, for example, by multiplying a coefficient by a function that approximates the characteristics of the change in haze ratio corresponding to mesh size 31 obtained in step Sa8-1. Similarly, the designer corrects the characteristics of the change in haze ratio corresponding to each of line width 32 and line thickness 33 based on the second measurement mesh conditions and the haze ratio of the prototype measured (Sa8-2).

[0085] The designer determines (Sa8-3) using a procedure similar to Sa3-2 whether or not mesh conditions exist that satisfy the target values, based on the characteristics of the change in opening ratio and the characteristics of the change in haze ratio corresponding to each of the mesh size 31, line width 32, and line thickness 33 corrected using the procedure Sa8-2, the characteristics of the change in SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity obtained using the procedure Sa3-1, the target transmittance, the target haze ratio, and the target SE value.

[0086] If the target values ​​are satisfied for all of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​exist (Sa8-3, Yes). On the other hand, if the target values ​​are not satisfied for any of the mesh size 31, line width 32, line thickness 33, and conductivity, the designer determines that mesh conditions that satisfy the target values ​​do not exist (Sa8-3, No). If the determination in step Sa8-3 is "No," the designer resets the first measured mesh conditions and the second measured mesh conditions (Sa9: second mesh condition resetting step). After step Sa9, the designer performs step Sa8-1 again.

[0087] In the procedure Sa9, the resetting of the first measurement mesh conditions and the resetting of the second measurement mesh conditions are not performed independently, but the mesh size 31, line width 32, and line thickness 33 are reset to the same ratio. For example, when resetting the mesh size 31, the ratio before and after resetting the mesh size 31 of the first measurement mesh conditions is reset to match the ratio before and after resetting the mesh size 31 of the second measurement mesh conditions. Note that the conductivity is reset so that the conductivity of the first measurement mesh conditions and the conductivity of the second measurement mesh conditions are the same value.

[0088] If the determination in step Sa8-3 is "Yes," the designer selects final specification mesh conditions in a procedure similar to step S10 in the first embodiment (Sa10: final specification mesh condition selection step). Note that in step S10 in the first embodiment, if step S9 has been performed, the provisional specification mesh conditions selected in step S5 are corrected based on the measured mesh conditions last reset in step S9 and the measured mesh conditions calculated in step S7 to select final specification mesh conditions. In the second embodiment, similar to the first embodiment, if step Sa9 has been performed, the provisional specification mesh conditions selected in step Sa5 are corrected. However, there are two measured mesh conditions that serve as indicators for the correction: the first measured mesh conditions and the second measured mesh conditions. Therefore, in step Sa10 in the second embodiment, the provisional specification mesh conditions selected in step Sa5 are corrected using either the first measured mesh conditions or the second measured mesh conditions to select final specification mesh conditions.

[0089] (Advantages of the second embodiment) The design procedure for the conductive mesh of the second embodiment has the following advantages in addition to those of the design procedure for the conductive mesh of the first embodiment. Specifically, the design procedure for the conductive mesh of the second embodiment includes an optical analysis simulation in addition to an electromagnetic field analysis simulation. Therefore, the aperture ratio change characteristics calculated by analytical calculation in the first embodiment can be obtained by optical analysis simulation, resulting in more accurate aperture ratio change characteristics. In the second embodiment, the haze ratio is further set as a target value, and the haze ratio change characteristics are obtained by optical analysis simulation. Therefore, it is possible to obtain final specification mesh conditions that satisfy the upper limit frequency, the target SE value, the target transmittance, and the target haze ratio. By manufacturing according to these final specification mesh conditions, it is possible to manufacture an electromagnetic shielding substrate 1 that has desired shielding performance and desired visibility.

[0090] <Third embodiment> Increasing the line thickness 33 in the electromagnetic shielding substrate 1 of the first embodiment can increase the SE value. In the method of printing the conductive lines 20 by spraying conductive ink, increasing the line thickness 33 requires applying multiple coats of the conductive ink. However, applying multiple coats of conductive ink can cause the bottom of the conductive lines 20 to widen, increasing the line width 32, or causing bleeding of the conductive lines 20 in areas where the multiple coats are not uniform. Therefore, increasing the line thickness 33 using the multiple coat method makes it difficult to achieve the width of the conductive lines 20 as specified. Therefore, even if an electromagnetic shielding substrate 1 that satisfies the target SE value can be produced using the multiple coat method, it may not result in an electromagnetic shielding substrate 1 that satisfies the target transmittance.

[0091] Therefore, in the third embodiment, as shown in FIG. 9 , the transparent substrate 10 is formed by stacking multiple sub-transparent substrates 10-1, 10-2, 10-3, .... Conductive lines 20 are printed on each of the multiple sub-transparent substrates 10-1, 10-2, 10-3, ... under the same mesh conditions and at the same positions. As a result, as shown in FIG. 9 , conductive lines 20v-1-1, 20v-1-2, 20v-1-3 are printed on the sub-transparent substrate 10-1 in the vertical direction. Similarly, conductive lines 20 are printed on the sub-transparent substrates 10-2, 10-3, ... in the vertical direction. Although not shown in FIG. 9 , conductive lines 20 are printed on each of the sub-transparent substrates 10-1, 10-2, 10-3, ... in the horizontal direction as well, in the same manner as in the vertical direction. As a result, conductive meshes having the same mesh size 31, the same line width 32, the same line thickness 33, and the same conductivity are formed at the same positions on each of the sub-transparent substrates 10-1, 10-2, 10-3, . . .

[0092] The sub-transparent substrates 10-1, 10-2, 10-3, etc., each having a conductive mesh formed thereon, are stacked at equal intervals. That is, as shown in FIG. 9, the sub-transparent substrates 10-1, 10-2, 10-3, etc. are stacked so that the distance between adjacent sub-transparent substrates 10-1, 10-2, 10-3, etc., indicated by reference numeral 90-1, is equal to the distance indicated by reference numeral 90-2. The stacking increases the apparent thickness of the conductive mesh, resulting in an electromagnetic shield substrate 1a with an SE value corresponding to the thickness. In this case, the line thickness 33 of each of the sub-transparent substrates 10-1, 10-2, 10-3, etc. can be made smaller than the line thickness 33 required to achieve the same SE value with a single transparent substrate 1. Reducing the line thickness 33 reduces the number of times conductive ink is applied to each of the sub-transparent substrates 10-1, 10-2, 10-3, etc. Therefore, it becomes easy to make the line width 32 of each of the sub-transparent base materials 10-1, 10-2, 10-3, . . . meet the specifications.

[0093] 9 shows an example in which three or more sub-transparent substrates 10-1, 10-2, 10-3, ... are stacked as a specific example, but any number of layers may be stacked as long as it is two or more. Also, as in the first embodiment, the number of conductive lines 20 may be any number as long as two or more conductive lines 20 are printed in each of the vertical and horizontal directions.

[0094] The design procedure for the conductive mesh in the third embodiment is the same as that of the conductive mesh in the first embodiment, except for the following steps. In step S2 of FIG. 3, when setting the provisional mesh conditions, in addition to the mesh size 31, line width 32, line thickness 33, and conductivity, the number of layers and the layer spacing are set as provisional mesh conditions. In step S3-1, an electromagnetic field analysis simulation is performed taking into account the number of layers and the layer spacing specified in the provisional mesh conditions, and the characteristics of the change in the SE value corresponding to each of the number of layers and the layer spacing are also obtained. Therefore, in step S3-2, a determination is made based on the characteristics of the change in the SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, number of layers, and layer spacing, the target SE value, and the target transmittance.

[0095] In step S6, a prototype for one layer is fabricated. In step S7, the actual mesh conditions are calculated based on the fabricated prototype for one layer. The number of layers and the layer spacing included in the actual mesh conditions are the number of layers and the layer spacing of the provisional specification mesh conditions. In step S8-1, an electromagnetic field analysis simulation is performed taking into account the number of layers and the layer spacing specified in the actual mesh conditions, and the characteristics of the change in the SE value corresponding to each of the number of layers and the layer spacing are also obtained. Therefore, in step S8-2, a judgment is made based on the characteristics of the change in the SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, number of layers, and layer spacing, the target SE value, and the target transmittance. In the resetting steps S4 and S9, resetting may be performed to change either the number of layers or the layer spacing, or both.

[0096] (Advantages of the third embodiment) The design procedure for the conductive mesh of the third embodiment has the following advantages in addition to the advantages of the design procedure for the conductive mesh of the first embodiment: For example, if the target SE value is set to the same value in the design procedure for the conductive mesh of the first embodiment and the design procedure for the conductive mesh of the third embodiment, the electromagnetic shielding substrates 1, 1a obtained by both design procedures can both satisfy the upper limit frequency, the target SE value, and the target transmittance as long as the target SE value is small.

[0097] Suppose the target SE value increases, and the mesh size 31 and line width 32 cannot be increased due to the constraints of the target transmittance. Therefore, the line thickness 33 must be increased to satisfy the target SE value. In this case, in the electromagnetic shield substrate 1 of the first embodiment, increasing the line thickness 33 requires more recoating of conductive ink, resulting in the actual width of the conductive line 20 being thicker than the line width 32 required for the final mesh specification. Therefore, in the first embodiment, as the target SE value increases, it becomes increasingly difficult to manufacture an electromagnetic shield substrate 1 that satisfies the target transmittance. In contrast, in the electromagnetic shield substrate 1a of the third embodiment, even if the target SE value increases, the line thickness 33 of each of the sub-transparent substrates 10-1, 10-2, 10-3, ... becomes smaller than in the first embodiment. Therefore, compared to the first embodiment, the third embodiment allows the actual width of the conductive line 20 to be maintained at the line width 32 required for the final mesh specification. Therefore, in the third embodiment, it is possible to more easily manufacture an electromagnetic shield substrate 1a that can satisfy the target transmittance even when the target SE value is large, compared to the first embodiment.

[0098] (Manufacturing procedure for electromagnetic shielding substrate) In the first and second embodiments, the mesh size 31, line width 32, and line thickness 33 of the final specification mesh conditions obtained through the conductive mesh design procedure are set in a printing device. Using this printing device, conductive ink having a conductivity that matches the conductivity of the final specification mesh conditions is sprayed onto the transparent substrate 10 to print the conductive lines 20. This makes it possible to manufacture an electromagnetic shielding substrate 1 that satisfies all target values.

[0099] When manufacturing the electromagnetic shield substrate 1a of the third embodiment, the mesh size 31, line width 32, and line thickness 33 of the final mesh conditions obtained through the conductive mesh design procedure are set in a printing device. Sub-transparent substrates 10-1, 10-2, 10-3, ... are prepared in a number that matches the number of layers of the final mesh conditions. Using the printing device, conductive ink with a conductivity that matches the conductivity of the final mesh conditions is sprayed onto each of the sub-transparent substrates 10-1, 10-2, 10-3, ... to print conductive lines 20. The sub-transparent substrates 10-1, 10-2, 10-3, ... with printed conductive lines 20 are stacked so that the positions of the conductive lines 20 are aligned and the stacking spacing is the final mesh conditions. This allows the manufacturing of an electromagnetic shield substrate 1a that satisfies all target values.

[0100] (Other configuration examples) As a modified example of the conductive wire mesh design procedure of the second embodiment, the procedure related to the haze ratio may be omitted. Specifically, a target haze ratio may not be set in step Sa1, the characteristics of the change in haze ratio may not be obtained in the optical analysis simulations Sa3-1 and Sa8-1, and the actual measurement of the haze ratio may not be performed in step Sa7-2. In other words, in this modified example, the procedure of applying the characteristics of the change in aperture ratio obtained in the optical analysis simulation instead of the characteristics of the change in aperture ratio calculated by analytical calculation in the first embodiment is performed.

[0101] The design procedure for the conductive mesh of the second embodiment and a modified example of the design procedure for the conductive mesh of the second embodiment may be applied as the design procedure for the conductive mesh of the third embodiment.

[0102] In the third embodiment, when the number of layers is two, instead of using two sub-transparent substrates 10-1 and 10-2, conductive lines 20v-1-1, 20v-1-2, and 20v-1-3 and conductive lines 20v-2-1, 20v-2-2, and 20v-2-3 may be printed on the upper and lower surfaces of a single transparent substrate 10 under the same mesh conditions, as shown in FIG. 10 . Note that while FIG. 10 illustrates an example of the vertical direction, conductive lines 20 are printed in the horizontal direction as well. In this case, the lamination interval is the thickness of the transparent substrate 10. As a result, when two layers are laminated, an electromagnetic shield substrate 1b that achieves the same effect as the method shown in FIG. 9 can be fabricated using fewer transparent substrates 10 than the method shown in FIG. 9 .

[0103] The design procedure for the conductive mesh in the case of FIG. 10 is the same as the design procedure for the conductive mesh of the third embodiment, except for the steps described below. Throughout the design procedure for the conductive mesh, the number of layers in the mesh conditions is fixed to "2," and the layer spacing is fixed to the thickness of the transparent substrate 10. These are not changed in the reset procedures of S4 and S9. In steps S3-1 and S8-1, an electromagnetic field analysis simulation is performed under the assumption that conductive wires 20 are present on the top and bottom surfaces of the transparent substrate 10, spaced apart by the thickness of the transparent substrate 10. In step S6, a prototype is fabricated in which conductive wires 20 are printed only on the top surface. Note that the design procedure for the conductive mesh in the case of FIG. 10 may be the design procedure for the conductive mesh of the second embodiment or a modified version of the design procedure for the conductive mesh of the second embodiment.

[0104] When manufacturing the electromagnetic shielding substrate 1b of the third embodiment shown in FIG. 10, the mesh size 31, line width 32, and line thickness 33 of the final specification mesh conditions obtained through the conductive mesh design procedure are set in a printing device. Using this printing device, conductive ink with a conductivity matching the conductivity of the final specification mesh conditions is sprayed onto the top and bottom surfaces of the transparent substrate 10 to print conductive lines 20. This makes it possible to manufacture an electromagnetic shielding substrate 1b that satisfies all target values.

[0105] In the first to third embodiments, the shape of each section of the conductive mesh is a square, but it may be a regular polygon such as a regular hexagonal honeycomb shape or a circle.

[0106] The following corrections may be made to the characteristics of the changes in the SE value corresponding to each of the mesh size 31, the wire width 32, the wire thickness 33, and the conductivity obtained by the electromagnetic field analysis simulation using the measured mesh conditions in S8-1 of the first embodiment as the analysis target. For example, before performing the step S8-1, an electromagnetic wave corresponding to the upper limit frequency of the target value is actually irradiated onto a prototype to measure the SE value of the prototype. The designer corrects the characteristics of the changes in the SE value corresponding to the mesh size 31 obtained in the step S8-1 so that the SE value matches the actually measured SE value at the position of the mesh size 31 under the measured mesh conditions. This correction is performed, for example, by multiplying a coefficient by a function that approximates the characteristics of the changes in the SE value corresponding to the mesh size 31 obtained in the step S8-1. The designer similarly corrects the characteristics of the changes in the SE value corresponding to each of the wire width 32, the wire thickness 33, and the conductivity based on the measured mesh conditions and the measured SE value of the prototype. By performing such a correction, it is possible to improve the accuracy of the characteristics of the change in the SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity obtained in the procedure S8-1. A similar correction may be performed on the characteristics of the change in the SE value corresponding to each of the mesh size 31, line width 32, line thickness 33, and conductivity obtained by the electromagnetic field analysis simulation using the first measured mesh condition of Sa8-1 of the second embodiment as the analysis target.

[0107] The embodiments of the present disclosure have been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0108] <Additional Notes> The design method of the conductive mesh described in each embodiment can be understood, for example, as follows.

[0109] (1) A method for designing a conductive mesh according to a first aspect includes a target value setting step of setting target values ​​for an upper limit frequency indicating an upper limit value of the frequency of an electromagnetic wave to be shielded, a target shielding effectiveness value indicating a target for the shielding effectiveness, and a target transmittance indicating a target for the transmittance of light; a tentative mesh condition setting step of setting tentative mesh conditions, which are mesh conditions indicating conditions for forming a conductive mesh formed by conductive lines printed on a transparent substrate and which are mesh conditions that satisfy the target values ​​within a predetermined manufacturable range; a first analysis and determination step of determining whether or not there are mesh conditions that satisfy the target values ​​in a predetermined analysis simulation that uses the tentative mesh conditions as an analysis target; and a second analysis and determination step of determining whether or not there are mesh conditions that satisfy the target values ​​in the first analysis and determination step. a measured mesh condition calculation step of measuring a prototype produced by printing the conductive wires on the transparent substrate in accordance with the provisional specification mesh conditions and calculating the mesh conditions of the prototype based on the measurement results to set them as measured mesh conditions; a second analysis determination step of determining whether or not mesh conditions that satisfy the target value exist in the predetermined analysis simulation in which the measured mesh conditions are the analysis target; and a final specification mesh condition selection step of selecting final specification mesh conditions according to the provisional specification mesh conditions if it is determined in the second analysis determination step that mesh conditions that satisfy the target value exist.

[0110] (2) A second aspect of the conductive mesh design method is the conductive mesh design method of (1), in which the mesh conditions are expressed by four parameters: a mesh size indicating the size of one section of the conductive mesh, the line width of the conductive wire, the line thickness of the conductive wire, and the conductivity of the conductive wire.

[0111] (3) A method for designing a conductive mesh according to a third aspect is the method for designing a conductive mesh according to (2), wherein the step of calculating the measured mesh conditions sets the wire thickness as half the measured thickness of the conductive wire of the prototype, sets the wire width as the width of the conductive wire when the thickness of the conductive wire of the prototype is half, calculates the mesh size based on the measured length of the opening of the conductive mesh and the wire width, and calculates the conductivity based on the measured sheet resistance of the prototype.

[0112] (4) A fourth aspect of the conductive mesh design method is the conductive mesh design method of (3), wherein the predetermined analytical simulation is an electromagnetic field analytical simulation, and each of the first analytical determination step and the second analytical determination step performs the electromagnetic field analytical simulation in which the cross-sectional shape of the conductive wire is modeled as a rectangular shape specified by the line width and the line thickness of the mesh condition to be analyzed, calculates a characteristic of change in shielding effectiveness for each parameter of the mesh condition, the characteristic corresponding to the upper limit frequency, and determines whether or not a mesh condition exists that satisfies the target value based on the calculated characteristic of change in shielding effectiveness, a characteristic of change in aperture ratio for each of the mesh size, the line width, and the line thickness that is calculated in advance, the target shielding effectiveness value, and the target transmittance.

[0113] (5) A fifth aspect of the conductive mesh design method is the conductive mesh design method of (3), wherein the measured mesh condition calculation step calculates a first measured mesh condition, which is the measured mesh condition described in (3), and a second measured mesh condition as the measured mesh conditions, and as the second measured mesh condition, the measured thickness of the conductive wire of the prototype is defined as the wire thickness, the measured width of the conductive wire of the prototype is defined as the line width, the mesh size is calculated based on the line width and the measured length of the opening of the conductive mesh, and the conductivity of the first measured mesh condition is defined as the conductivity.

[0114] (6) A sixth aspect of the conductive mesh design method is the conductive mesh design method of (5), wherein the predetermined analysis simulation is an electromagnetic field analysis simulation and an optical analysis simulation, and the first analysis determination step performs the electromagnetic field analysis simulation in which a cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the provisional mesh condition, to calculate a characteristic of change in shielding effectiveness for each parameter of the mesh condition, the characteristic corresponding to the upper limit frequency, and performs the optical analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the provisional mesh condition, to calculate a characteristic of change in aperture ratio corresponding to each of the mesh size, the line width, and the line thickness, and combines the calculated characteristic of change in shielding effectiveness and the characteristic of change in aperture ratio with the target shielding effectiveness value. and the second analysis determination step performs the electromagnetic field analysis simulation in which the cross-sectional shape of the conductive wire is modeled as a rectangular shape specified by the line width and the line thickness of the first measured mesh condition, to calculate characteristics of change in shielding effectiveness for each parameter of the mesh condition, the characteristics corresponding to the upper limit frequency, and performs the optical analysis simulation in which the cross-sectional shape of the conductive wire is modeled as a rectangular shape specified by the line width and the line thickness of the second measured mesh condition, to calculate characteristics of change in aperture ratio corresponding to each of the mesh size, the line width, and the line thickness, and determines whether or not mesh conditions that satisfy the target value exist based on the calculated characteristics of change in shielding effectiveness and the characteristics of change in aperture ratio, the target shielding effectiveness value, and the target transmittance.

[0115] (7) A seventh aspect of the conductive mesh design method is the conductive mesh design method of (6), which includes a transmittance measurement step of measuring the transmittance of the prototype, and the second analysis and determination step corrects the calculated characteristics of the change in opening ratio corresponding to each of the mesh size, the line width, and the line thickness according to the measured transmittance of the prototype, and uses the corrected characteristics of the change in opening ratio to determine whether or not there are mesh conditions that satisfy the target value.

[0116] (8) A conductive mesh design method according to an eighth aspect is the conductive mesh design method according to (6) or (7), wherein the target value setting step further sets a target haze ratio indicating a target haze ratio as the target value, and each of the first analysis determination step and the second analysis determination step performs the optical analysis simulation in which the cross-sectional shape of the conductive wire is modeled as a rectangular shape specified by the line width and the line thickness of the mesh condition to be analyzed, calculates characteristics of change in haze ratio corresponding to each of the mesh size, the line width, and the line thickness, and determines whether or not a mesh condition that satisfies the target value exists based on the calculated characteristics of change in shielding effectiveness, the characteristics of change in aperture ratio, and the characteristics of change in haze ratio, the target shielding effectiveness value, the target transmittance, and the target haze ratio.

[0117] (9) A ninth aspect of the conductive mesh design method is the conductive mesh design method of (8), which includes a haze ratio measurement step of measuring the haze ratio of the prototype, and the second analysis and determination step corrects the calculated characteristics of the change in haze ratio corresponding to each of the mesh size, the line width, and the line thickness according to the measured haze ratio of the prototype, and uses the corrected characteristics of the change in haze ratio to determine whether or not there are mesh conditions that satisfy the target value.

[0118] (10) A tenth aspect of the conductive mesh design method is a conductive mesh design method according to any one of (1) to (9), which includes a first mesh condition resetting step of resetting the provisional mesh conditions when it is determined in the first analysis determination step that no mesh conditions exist that satisfy the target value, and the first analysis determination step performs the specified analysis simulation, with the provisional mesh conditions reset in the first mesh condition resetting step as the analysis target.

[0119] (11) A conductive mesh design method according to an eleventh aspect is a conductive mesh design method according to any one of (1) to (10), further comprising a second mesh condition resetting step of resetting the measured mesh conditions when it is determined in the second analysis determination step that no mesh conditions that satisfy the target value exist, wherein the second analysis determination step performs the predetermined analysis simulation using the measured mesh conditions reset in the second mesh condition resetting step as the analysis object, and the final specification mesh condition selection step, when it is determined in the second analysis determination step that mesh conditions that satisfy the target value exist, selects the provisional specification mesh conditions as the final specification mesh conditions when the measured mesh conditions of the analysis object of the second analysis determination step have not been reset, and selects the final specification mesh conditions based on the reset measured mesh conditions and the provisional specification mesh conditions when the measured mesh conditions of the analysis object of the second analysis determination step have been reset.

[0120] (12) A method for designing a conductive mesh according to a twelfth aspect is a method for designing a conductive mesh according to any one of (1) to (11), wherein the transparent substrate is formed by stacking a plurality of sub-transparent substrates on which the conductive lines are printed at opposing positions, the mesh conditions are represented by six parameters: a mesh size indicating the size of one section of the conductive mesh, the line width of the conductive lines, the line thickness of the conductive lines, the conductivity of the conductive lines, the number of layers, and the layer spacing, and the predetermined analytical simulation is performed taking into account the number of layers and the layer spacing.

[0121] (13) A method for designing a conductive mesh according to a thirteenth aspect is a method for designing a conductive mesh according to any one of (1) to (12), wherein the conductive lines are printed on the upper surface of the transparent substrate and at a position on the lower surface opposite to the printing position on the upper surface, and the predetermined analytical simulation is performed taking into account that the conductive lines are printed on the upper surface of the transparent substrate and at a position on the lower surface opposite to the printing position on the upper surface. [Explanation of symbols]

[0122] 1. Electromagnetic shielding substrate 10 Transparent base material 11-1, 11-2, 11-3, 11-4 mesh areas 20v-1,20v-2,20v-3,20h-1,20h-2,20h-3 Conductive wire 31 mesh size 32 Line Width 33 Line thickness 41 Maximum opening size

Claims

1. a target value setting step of setting, as target values, an upper limit frequency indicating an upper limit value of the frequency of an electromagnetic wave to be shielded, a target shielding effectiveness value indicating a target of the shielding effectiveness, and a target transmittance indicating a target of the transmittance of light; a provisional mesh condition setting step of setting provisional mesh conditions that indicate conditions for forming a conductive mesh formed by conductive lines printed on a transparent substrate, the provisional mesh conditions being mesh conditions that satisfy the target value within a predetermined manufacturable range; a first analysis determination step of determining whether or not there is a mesh condition that satisfies the target value in a predetermined analysis simulation that uses the provisional mesh condition as an analysis object; a provisional specification mesh condition selection step of selecting provisional specification mesh conditions based on the provisional mesh conditions to be determined when it is determined in the first analysis determination step that mesh conditions that satisfy the target value exist; a step of actually measuring a prototype produced by printing the conductive wire on the transparent substrate in accordance with the provisional specification mesh conditions, and calculating mesh conditions for the prototype based on the measurement results to set the mesh conditions as actual measurement mesh conditions; a second analysis determination step of determining whether or not there is a mesh condition that satisfies the target value in the predetermined analysis simulation that uses the measured mesh condition as an analysis target; a final specification mesh condition selection step of selecting final specification mesh conditions according to the provisional specification mesh conditions when it is determined in the second analysis determination step that mesh conditions that satisfy the target value exist; A method for designing a conductive mesh having the following features:

2. The mesh conditions are represented by four parameters: a mesh size indicating the size of one section of the conductive mesh, a line width of the conductive line, a line thickness of the conductive line, and a conductivity of the conductive line. The method for designing a conductive mesh according to claim 1 .

3. The measured mesh condition calculation step sets, as the measured mesh conditions, a length that is half the thickness of the conductive wire of the prototype as the wire thickness, a width of the conductive wire when the thickness of the conductive wire of the prototype is half as the line width, calculates the mesh size based on the measured length of the opening of the conductive mesh and the line width, and calculates the conductivity based on the measured sheet resistance of the prototype. The method for designing a conductive mesh according to claim 2 .

4. the predetermined analytical simulation is an electromagnetic field analytical simulation, Each of the first analysis and determination step and the second analysis and determination step comprises: performing the electromagnetic field analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of each mesh condition to be analyzed, calculating a characteristic of change in shielding effect for each parameter of the mesh condition, the characteristic corresponding to the upper limit frequency, and determining whether or not a mesh condition exists that satisfies the target value based on the calculated characteristic of change in shielding effect, a characteristic of change in aperture ratio for each of the mesh size, the line width, and the line thickness that is calculated in advance, the target shielding effectiveness value, and the target transmittance; The method for designing a conductive mesh according to claim 3 .

5. The measured mesh condition calculation step calculates a first measured mesh condition and a second measured mesh condition as the measured mesh conditions, and for the second measured mesh condition, the measured thickness of the conductive wire of the prototype is set as the wire thickness, the measured width of the conductive wire of the prototype is set as the line width, the mesh size is calculated based on the line width and the measured length of an opening of the conductive mesh, and the conductivity of the first measured mesh condition is set as the conductivity. The method for designing a conductive mesh according to claim 3 .

6. the predetermined analysis simulation is an electromagnetic field analysis simulation and an optical analysis simulation, The first analysis and determination step includes: performing the electromagnetic field analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the provisional mesh condition, and calculating a characteristic of change in shielding effect for each parameter of the mesh condition, the characteristic corresponding to the upper limit frequency; performing the optical analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the provisional mesh condition, and calculating a characteristic of change in aperture ratio corresponding to each of the mesh size, the line width, and the line thickness; and determining whether or not a mesh condition exists that satisfies the target value, based on the calculated characteristic of change in shielding effect and the characteristic of change in aperture ratio, the target shielding effectiveness value, and the target transmittance; The second analysis and determination step includes: performing the electromagnetic field analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the first measured mesh condition, and calculating a characteristic of change in shielding effect for each parameter of the mesh condition, the characteristic corresponding to the upper limit frequency; performing the optical analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of the second measured mesh condition, and calculating a characteristic of change in aperture ratio corresponding to each of the mesh size, the line width, and the line thickness; and determining whether or not a mesh condition exists that satisfies the target value, based on the calculated characteristic of change in shielding effect and the characteristic of change in aperture ratio, the target shielding effectiveness value, and the target transmittance. The method for designing a conductive mesh according to claim 5 .

7. A transmittance measurement step of measuring the transmittance of the prototype, The second analysis and determination step includes: the calculated characteristics of the change in the aperture ratio corresponding to each of the mesh size, the line width, and the line thickness are corrected in accordance with the actually measured transmittance of the prototype, and the corrected characteristics of the change in the aperture ratio are used to determine whether or not a mesh condition that satisfies the target value exists; The method for designing a conductive mesh according to claim 6 .

8. The target value setting step further includes setting a target haze ratio indicating a target haze ratio as the target value, Each of the first analysis and determination step and the second analysis and determination step comprises: performing the optical analysis simulation in which the cross-sectional shape of the conductive line is modeled as a rectangular shape specified by the line width and the line thickness of each mesh condition to be analyzed, and calculating characteristics of changes in haze ratio corresponding to each of the mesh size, the line width, and the line thickness; and determining whether or not there are mesh conditions that satisfy the target values ​​based on the calculated characteristics of changes in shielding effectiveness, the characteristics of changes in aperture ratio, and the characteristics of changes in haze ratio, the target shielding effectiveness value, the target transmittance, and the target haze ratio; The method for designing a conductive mesh according to claim 6 .

9. A haze ratio measurement step of measuring the haze ratio of the prototype, The second analysis and determination step includes: The calculated characteristics of the change in haze ratio corresponding to each of the mesh size, the line width, and the line thickness are corrected according to the haze ratio of the prototype that is actually measured, and the corrected characteristics of the change in haze ratio are used to determine whether or not there are mesh conditions that satisfy the target value. The method for designing a conductive mesh according to claim 8.

10. a first mesh condition resetting step of resetting the provisional mesh condition when it is determined in the first analysis determination step that no mesh condition exists that satisfies the target value; the first analysis determination step performs the predetermined analysis simulation using the provisional mesh conditions reset in the first mesh condition resetting step as an analysis target; The method for designing a conductive mesh according to claim 1 .

11. a second mesh condition resetting step of resetting the actual measurement mesh condition when it is determined in the second analysis determination step that there is no mesh condition that satisfies the target value; the second analysis determination step performs the predetermined analysis simulation using the actual measurement mesh conditions reset in the second mesh condition resetting step as an analysis target; In the final specification mesh condition selection step, when it is determined in the second analysis determination step that mesh conditions that satisfy the target value exist, if the measured mesh conditions of the analysis target in the second analysis determination step have not been reset, the provisional specification mesh conditions are selected as the final specification mesh conditions, and if the measured mesh conditions of the analysis target in the second analysis determination step have been reset, the final specification mesh conditions are selected based on the reset measured mesh conditions and the provisional specification mesh conditions. The method for designing a conductive mesh according to claim 1 .

12. the transparent substrate is formed by stacking a plurality of sub-transparent substrates, each having the conductive line printed thereon, at positions facing each other; The mesh conditions are represented by six parameters: a mesh size indicating the size of one section of the conductive mesh, a line width of the conductive wire, a line thickness of the conductive wire, a conductivity of the conductive wire, the number of layers, and a layer spacing; the predetermined analytical simulation is performed taking into consideration the number of layers and the layer spacing; A method for designing a conductive mesh according to any one of claims 1 to 11.

13. the conductive lines are printed on the upper surface of the transparent substrate and at positions on the lower surface opposite to the printing positions on the upper surface; the predetermined analytical simulation is performed taking into consideration that the conductive lines are printed on the upper surface of the transparent base material and that the conductive lines are printed on a position on the lower surface opposite to the printing position on the upper surface. A method for designing a conductive mesh according to any one of claims 1 to 11.

14. A method for manufacturing an electromagnetic shielding substrate, comprising the steps of: printing the conductive lines on the transparent substrate in accordance with the final specification mesh conditions selected by the conductive mesh design method according to claim 1;

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