Metal foil for spring members, method for manufacturing metal foil for spring members, and method for manufacturing spring members for electronic devices

Abstract

To provide a spring member metal foil which offers suppressed variation in width in a thickness direction of a spring member formed therefrom, and to provide a method of manufacturing the same and an electronic device spring member.SOLUTION: A spring member metal foil 10 provided herein has a first area 10R1 having a square shape with a side of 300 mm for forming a spring member. In the first area 10R1, a difference value obtained by subtracting a variance of thickness T thereof in a width direction DW perpendicular to a rolling direction DR from a variance of the thickness T in the rolling direction DR is 0.15 μm2 or less in absolute terms.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a metal foil for a spring member, a manufacturing method for the metal foil for a spring member, and a spring member for electronic devices. [Background technology]

[0002] Camera modules installed in electronic devices with cameras, such as tablet terminals and smartphones, are equipped with a drive mechanism that enables autofocus and zoom. Known drive mechanisms include a lens drive system and a sensor drive system. The drive mechanism of the lens drive system is equipped with a leaf spring that enables the position of the lens to be changed in the direction of the optical axis of the lens. In contrast, the drive mechanism of the sensor drive system is equipped with a leaf spring that enables the position of the image sensor to be changed in the direction of the optical axis of the lens (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-059345 A [Patent Document 2] JP 2020-170170 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, leaf springs are required to satisfy a specific spring load or deflection within a limited volume, and in order to satisfy the requirements for spring load and deflection, the leaf springs must be made of a metal with high hardness.

[0005] The width and thickness of the leaf spring greatly affect the spring load and deflection. The metal foil, which is the raw material of the leaf spring, is thinned to a predetermined thickness by rolling. Since the metal foil is made of a metal with high hardness, it is more difficult to make the thickness of the metal foil uniform by rolling than when it is made of a metal with low hardness.

[0006] On the other hand, leaf springs are formed by wet etching of metal foil. Variations in the thickness of the metal foil cause variations in the amount of etching, which in turn causes variations in the width of the leaf spring in the thickness direction. Variations in the width of the leaf spring in the thickness direction cause variations in the spring load and deflection of the leaf spring, so it is necessary to suppress the variation in the spring width in the thickness direction. [Means for solving the problem]

[0007] The metal foil for a spring member for solving the above problems has a square shape with a side length of 300 mm, and includes a first region for forming the spring member. In the first region, the absolute value of the difference obtained by subtracting the thickness variance in the width direction perpendicular to the rolling direction from the thickness variance in the rolling direction is 0.15 μm. 2 The following is the result.

[0008] A method for manufacturing metal foil for spring members for solving the above problems includes rolling a base material, preparing a plurality of rolled materials obtained by rolling the base material, and then selecting the metal foil for spring members from the plurality of rolled materials. The rolled material has a square shape with a side length of 300 mm, and a region in which the spring member is to be formed is a first region. By selecting the metal foil for spring members, a difference value obtained by subtracting the thickness variance in the width direction perpendicular to the rolling direction from the thickness variance in the rolling direction in the first region is selected from the plurality of rolled materials, and the absolute value of the difference value is 0.15 μm. 2 The rolled material having the following properties is selected as the metal foil for a spring member.

[0009] The spring member for electronic equipment to solve the above problem is a spring member for electronic equipment using a metal foil for spring members, wherein the absolute value of a difference value obtained by subtracting the thickness variance in the width direction perpendicular to the rolling direction from the thickness variance in the rolling direction of the metal foil for spring members is 0.15 μm 2 The following is the result.

[0010] According to each of the above configurations, the absolute value of the difference between the first dispersion and the second dispersion is 0.15 μm 2 Since the thickness of the metal foil for the spring member is less than or equal to the thickness of the metal foil for the spring member, the spring member formed by wet etching the metal foil for the spring member has less variation in width in the thickness direction.

[0011] In the metal foil for a spring member, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction may be 0.15 μm or less.

[0012] In the metal foil for a spring member, in the first region, a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm 2 It may be the following.

[0013] In the above-mentioned metal foil for spring members, in the first region, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction is a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction is a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0014] In the metal foil for a spring member, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 It may be the following.

[0015] In the above-mentioned metal foil for spring members, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction may be 0.15 μm or less, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction may be a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction may be a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0016] In the metal foil for a spring member, in the first region, a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm 2 or less, and in the first region, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction is a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction is a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0017] In the metal foil for a spring member, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is a first difference value, a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0018] In the above-mentioned manufacturing method of metal foil for spring members, the condition for selecting the metal foil for spring members may include that, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less.

[0019] In the above-mentioned method for producing a metal foil for a spring member, the selection of the metal foil for a spring member includes a condition for selecting the metal foil for a spring member, in the first region, where a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 It may include the following:

[0020] In the above-mentioned manufacturing method of metal foil for spring members, in the first region, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction is a first difference value, and a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction is a second difference value, and sorting the metal foil for spring members may include, as a condition for sorting the metal foil for spring members, that an absolute value of the difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0021] In the above-mentioned method for producing a metal foil for a spring member, the selection of the metal foil for a spring member includes the selection of the metal foil for a spring member being such that, in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 It may include the following:

[0022] In the above-mentioned manufacturing method of metal foil for spring members, in the first region, a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is a first difference value, and a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is a second difference value, and the manufacturing method of metal foil for spring members may include, as conditions for selecting the metal foil for spring members, that in the first region, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0023] In the above-mentioned method for producing a metal foil for a spring member, in the first region, a difference value obtained by subtracting a minimum value from a maximum value of the thickness in the rolling direction is a first difference value, and a difference value obtained by subtracting a minimum value from a maximum value of the thickness in the width direction is a second difference value, and the selection of the metal foil for a spring member includes a condition for selecting the metal foil for a spring member, in the first region, where a difference value obtained by subtracting a variance of the thickness in the width direction from a variance of the thickness in the rolling direction is 0.15 μm or less. 2 and an absolute value of a difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0024] In the above-mentioned method for producing a metal foil for a spring member, in the first region, a difference value obtained by subtracting a minimum value from a maximum value of the thickness in the rolling direction is a first difference value, and a difference value obtained by subtracting a minimum value from a maximum value of the thickness in the width direction is a second difference value, and the selection of the metal foil for a spring member includes: selecting a thickness of the metal foil for a spring member that is equal to or smaller than 0.15 μm in the first region; selecting a thickness of the metal foil for a spring member that is equal to or smaller than 0.15 μm in the first region; 2 and an absolute value of a difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0025] In the spring component for electronic equipment, in the metal foil for a spring component, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction may be 0.15 μm or less.

[0026] In the above spring member for electronic equipment, in the metal foil for a spring member, a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm. 2 It may be the following.

[0027] In the above-mentioned spring component for electronic devices, in the metal foil for the spring component, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction is a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction is a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0028] In the above spring member for electronic equipment, in the metal foil for a spring member, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 It may be the following.

[0029] In the above-mentioned spring component for electronic devices, in the metal foil for the spring component, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction may be 0.15 μm or less, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction may be a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction may be a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0030] In the above-mentioned spring component for electronic devices, in the metal foil for the spring component, a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction may be 0.15 μm or less, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the rolling direction may be a first difference value, a difference value obtained by subtracting the maximum value from the minimum value of the thickness in the width direction may be a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0031] In the above spring member for electronic equipment, in the metal foil for a spring member, a difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is 0.15 μm or less, and a difference value obtained by subtracting the variance of the thickness in the width direction from the variance of the thickness in the rolling direction is 0.15 μm or less. 2 a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is a first difference value, a difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is a second difference value, and an absolute value of the difference value obtained by subtracting the second difference value from the first difference value may be 0.8 μm or less.

[0032] According to each of the above configurations, the metal foil for a spring member satisfies at least one of the following conditions. The difference between the first standard deviation and the second standard deviation is 0.15 μm or less. The difference between the first dispersion and the second dispersion is 0.15 μm or less. The absolute value of the difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0033] This reduces the variation in thickness of the metal foil for the spring member, and therefore reduces the variation in width in the thickness direction of the spring member formed by wet etching the metal foil for the spring member.

[0034] In the above metal foil for a spring member, the metal foil for a spring member may include any one selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper.

[0035] In the above-mentioned method for manufacturing a metal foil for a spring member, the metal foil for a spring member may include any one selected from the group consisting of a stainless steel alloy, a beryllium copper, a nickel-tin copper, a phosphor bronze, a Corson alloy, and a titanium copper.

[0036] In the spring member for electronic devices, the metal foil for the spring member may include any one selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper.

[0037] According to each of the above configurations, the metal foil for a spring member can have high hardness, so that the durability of the spring member formed from the metal foil for a spring member can be increased. Effect of the Invention

[0038] According to the present invention, it is possible to suppress variation in the spring width in the thickness direction of a spring member formed from metal foil. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a perspective view showing a structure of a metal foil for a spring member in one embodiment. [Diagram 2] FIG. 2 is a plan view showing the structure of the spring member for an electronic device in the embodiment. [Diagram 3] FIG. 3 is a process diagram illustrating the method for producing the metal foil for a spring member in the embodiment. [Figure 4] FIG. 4 is a process diagram illustrating the method for producing the metal foil for a spring member in the embodiment. [Diagram 5] FIG. 5 is a process diagram illustrating the method for producing the metal foil for a spring member in the embodiment. [Figure 6] FIG. 6 is a process chart for explaining the method for manufacturing the spring component for electronic equipment shown in FIG. [Figure 7] FIG. 7 is a process diagram for explaining the method for manufacturing the spring member for electronic equipment shown in FIG. [Figure 8] FIG. 8 is a process chart for explaining the method for manufacturing the spring component for electronic equipment shown in FIG. [Figure 9] FIG. 9 is a process chart for explaining the method for manufacturing the spring component for electronic equipment shown in FIG. [Figure 10] FIG. 10 is a process chart for explaining the method for manufacturing the spring component for electronic equipment shown in FIG. [Figure 11] FIG. 11 is a plan view for explaining the measurement points of the thickness of the metal foil for a spring member. [Figure 12] FIG. 12 is a table showing the measurement results for the metal foils of the examples and the comparative examples. [Figure 13] FIG. 13 is a graph showing the relationship between the first absolute value and the difference value of the spring width. [Figure 14] FIG. 14 is a graph showing the relationship between the second absolute value and the difference value of the spring width. [Figure 15] FIG. 15 is a graph showing the relationship between the third absolute value and the difference value of the spring width. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] An embodiment of a metal foil for a spring member, a method for manufacturing the metal foil for a spring member, and a spring member for electronic devices will be described with reference to Figs. [Metal foil for spring components] The metal foil for a spring member will be described with reference to FIG.

[0041] In the metal foil for spring members (hereinafter also referred to as metal foil) 10 shown in FIG. 1, the region for forming the spring member is the first region 10R1. The first region 10R1 has a square shape with a side length of 300 mm. The metal foil 10 is a rolled material formed from a metal having a high degree of hardness capable of realizing the spring load or deflection required for the spring member. The metal foil 10 has a belt shape extending along the rolling direction DR. The direction perpendicular to the rolling direction DR is the width direction DW. The thickness T of the metal foil 10 is, for example, 150 μm or less, and preferably 50 μm or more and 120 μm or less. The thickness of the metal foil 10 has a uniformity such that the ratio of the difference between the maximum value and the minimum value of the thickness T of the metal foil 10 to the average value of the thickness of the base material is 3% or less.

[0042] The metal foil 10 satisfies the following condition 1. (Condition 1) The absolute value of the difference between the first dispersion and the second dispersion is 0.15 μm 2 The following is the result.

[0043] The thickness variance in the rolling direction DR is the first variance, and the thickness variance in the width direction DW is the second variance. The absolute value of the difference obtained by subtracting the second variance from the first variance is the second absolute value. The first variance is the variance in thickness at each point on a line extending along the rolling direction DR. The second variance is the variance in thickness at each point on a line extending along the width direction DW.

[0044] The second absolute value is 0.15 μm 2 8. Since the thickness of the metal foil 10 is less than or equal to the thickness of the metal foil 10, the variation in the spring width in the thickness direction of the spring member formed by wet etching the metal foil 10 is therefore reduced.

[0045] The metal foil 10 has a front surface 10F and a back surface 10B opposite to the front surface 10F. The thickness T of the metal foil 10 is the distance between the front surface 10F and the back surface 10B. The maximum and minimum values ​​of the thickness in the rolling direction DR are specified as follows. That is, a first measurement area R1R having a band shape extending along the rolling direction DR is set for the first region 10R1. The length of the first measurement area R1R in the width direction DW is, for example, 20 mm. Among the thicknesses of the metal foil 10 measured at each of a plurality of points on a straight line included in the first measurement area R1R, the largest value is the maximum value, and the smallest value is the minimum value.

[0046] The maximum and minimum values ​​of the thickness in the width direction DW are specified as follows. That is, a second measurement area R1W having a strip shape extending along the width direction DW is set for the first area 10R1. The length of the second measurement area R1W in the rolling direction DR is, for example, 20 mm. Among the thicknesses of the metal foil 10 measured at each of a plurality of points on a straight line included in the second measurement area R1W, the largest value is the maximum value, and the smallest value is the minimum value.

[0047] In the metal foil 10, the thickness variation in the rolling direction DR becomes smaller as the material for manufacturing the metal foil 10 is repeatedly rolled. Therefore, from the viewpoint of suppressing the variation in the rolling direction DR, it is preferable to increase the number of times of rolling performed during the manufacture of the metal foil 10. However, the metal foil 10 for the spring member needs to have a thickness equal to or greater than a predetermined value in terms of realizing the spring load or deflection required for the spring member. Therefore, in the metal foil 10 for the spring member, it is difficult to perform the number of times of rolling that can eliminate the thickness variation in the rolling direction DR during the manufacture of the metal foil 10. In contrast, in the metal foil 10, the thickness variation in the width direction DW is governed by the surface condition of the rolling roller used for rolling, so the variation tends to be suppressed regardless of the number of times of rolling. Therefore, the second dispersion of the metal foil 10 tends to be equal to or less than the first dispersion.

[0048] On the other hand, when wet etching is performed on the metal foil 10 to form through-holes penetrating the metal foil 10 along the thickness direction of the metal foil 10, the thinner the part of the metal foil 10, the shorter the time required for the through-holes to be formed. The through-holes formed in the metal foil 10 form a flow of the etching solution between the front surface 10F and the back surface 10B of the metal foil 10, but hardly contribute to the progress of isotropic etching of the metal foil 10 in a direction perpendicular to the penetrating direction. In contrast, the thicker the part of the metal foil 10, the longer the time required for the through-holes to be formed. Therefore, the thicker part of the metal foil 10 contributes greatly to the progress of isotropic etching of the metal foil 10.

[0049] Therefore, the first variance can be used as an index of the likelihood of isotropic etching occurring in the rolling direction DR in the thickness of the metal foil 10. Also, the second variance can be used as an index of the likelihood of isotropic etching occurring in the width direction DW in the thickness of the metal foil 10. Furthermore, the first absolute value can be used as an index of the likelihood of isotropic etching occurring in the rolling direction DR relative to the width direction DW in which isotropic etching is less likely to occur.

[0050] In this regard, when the metal foil 10 satisfies the above-mentioned condition 1, the tendency of isotropic etching in the rolling direction DR to occur is suppressed from becoming excessively large when the tendency of isotropic etching in the width direction DW is taken as a standard. Therefore, the spring member formed by etching the metal foil 10 can easily have a desired shape.

[0051] In the first region 10R1, the standard deviation of the thickness T in the rolling direction DR is the first standard deviation. That is, the first standard deviation is the standard deviation of the thickness T at each point on a line along the rolling direction DR. In the first region 10R1, the standard deviation of the thickness T in the width direction DW is the second standard deviation. That is, the second standard deviation is the standard deviation of the thickness T at each point on a line along the width direction DW.

[0052] In the first region 10R1, the difference between the maximum and minimum values ​​of the thickness T in the rolling direction DR is the first difference value. That is, the thickness T at each point on a line along the rolling direction DR is the first thickness, and the difference between the maximum and minimum values ​​of the first thickness is the first difference value. In the first region 10R1, the difference between the maximum and minimum values ​​of the thickness T in the width direction DW is the second difference value. That is, the thickness at each point on a line along the width direction DW is the second thickness, and the difference between the maximum and minimum values ​​of the second thickness is the second difference value.

[0053] The metal foil 10 preferably satisfies at least one of the following conditions 2 to 4. That is, the metal foil 10 may satisfy only one of conditions 2 to 4, or may satisfy two or more selected from conditions 2 to 4.

[0054] (Condition 2) The difference value obtained by subtracting the second standard deviation from the first standard deviation is 0.15 μm or less. The difference value obtained by subtracting the second standard deviation from the first standard deviation is the third difference value.

[0055] (Condition 3) The difference between the first dispersion and the second dispersion is 0.15 μm 2 The following is the result. The difference value obtained by subtracting the second variance from the first variance is the fourth difference value. (Condition 4) The absolute value of the difference value obtained by subtracting the second difference value from the first difference value is 0.8 μm or less.

[0056] The absolute value of the difference value obtained by subtracting the second difference value from the first difference value is a third absolute value. When the metal foil 10 satisfies conditions 2 to 4, the tendency of isotropic etching in the rolling direction DR to occur is prevented from becoming excessively large when the tendency of isotropic etching in the width direction DW is taken as a standard, as in the case where condition 1 is satisfied. Therefore, the spring member formed by etching the metal foil 10 is likely to have a desired shape.

[0057] As described above, the metal foil 10 is formed from a metal having a high hardness to the extent that the spring load or deflection required for the spring member manufactured using the metal foil 10 can be realized. The metal foil 10 may be formed from, for example, a stainless steel alloy or a copper alloy. The stainless steel alloy may be, for example, a stainless steel alloy specified in JIS G 4313:2011 "Stainless steel strip for springs". The copper alloy may be, for example, a copper alloy specified in JIS H 3130:2018 "Beryllium copper, titanium copper, phosphor bronze, nickel-tin copper and nickel silver plate and strip for springs".

[0058] The metal foil 10 preferably contains any one selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper, which allows the metal foil 10 to have high hardness, thereby making it possible to increase the durability of the spring member formed from the metal foil 10.

[0059] [Spring material] The spring member will be described with reference to Fig. 2. Fig. 2 shows a schematic planar structure of the spring member as viewed from a viewpoint opposite to the plane in which the spring member extends.

[0060] As shown in FIG. 2, the spring member 20 includes an outer frame portion 21, an inner frame portion 22, and a spring portion 23. The spring member 20 is a leaf spring. In the example shown in FIG. 2, the outer shape of the outer frame portion 21 is octagonal, and the outer shape of the inner frame portion 22 is circular. The spring portion 23 has a folded line shape. The outer shapes of the outer frame portion 21 and the inner frame portion 22 may be changed according to the shapes of other members included in the drive mechanism of the camera module in which the spring member 20 is mounted, that is, members other than the spring member 20. The inner frame portion 22 is located within an area defined by the outer frame portion 21. The spring portion 23 connects the inner frame portion 22 to the outer frame portion 21.

[0061] In the lens drive type drive mechanism, a pair of spring members 20 are arranged to sandwich the lens in the optical axis direction of the lens. In the optical axis direction, the position of the inner frame portion 22 connected to each outer frame portion 21 changes relative to that outer frame portion 21, thereby changing the position of the lens in the optical axis direction. This makes it possible to correct camera shake using the lens drive type drive mechanism.

[0062] In contrast, in a sensor-driven drive mechanism, a pair of spring members 20 are disposed to sandwich the image sensor in the optical axis direction of the lens. In the optical axis direction, the position of the inner frame portion 22 connected to each outer frame portion 21 changes relative to that outer frame portion 21, thereby changing the position of the image sensor in the optical axis direction of the lens. This makes it possible to correct camera shake using the sensor-driven drive mechanism.

[0063] In the spring member 20, in a plan view facing the plane in which the spring member 20 extends, the length in a direction perpendicular to the direction in which each side of the outer frame portion 21 extends is the width of the spring member 20 at the outer frame portion 21. In addition, in a plan view facing the plane in which the spring member 20 extends, the length of the inner frame portion 22 along the radial direction of the inner frame portion 22 is the width of the spring member 20 at the inner frame portion 22. In addition, in a plan view facing the plane in which the spring member 20 extends, the line width of the fold line in the spring portion 23 in the plan view is the width of the spring portion 23, i.e., the spring width SW.

[0064] The electronic device in which the camera module having the spring member 20 is mounted may be, for example, a mobile phone terminal, a smartphone, a tablet terminal, or a notebook personal computer.

[0065] [Method of manufacturing metal foil for spring components] A method for producing the metal foil 10 will be described with reference to FIGS. The method for producing the metal foil 10 includes rolling a base material, preparing a plurality of rolled materials obtained by rolling the base material, and then selecting the metal foil 10 from the plurality of rolled materials. In selecting the metal foil 10, a rolled material that satisfies the above-mentioned condition 1 is selected as the metal foil 10 from the plurality of rolled materials. The method for producing the metal foil 10 may further include at least one of the above-mentioned conditions 2 to 4 as the conditions for selecting the metal foil 10 from the plurality of rolled materials. That is, only one of conditions 2 to 4 may be included, or two or more selected from conditions 2 to 4 may be included.

[0066] The method for producing the metal foil 10 will be described in more detail below with reference to the drawings. 3 and 4 show schematic diagrams of the process of rolling the base material to form the metal foil 10. FIG.

[0067] 3, when the metal foil 10 is manufactured, a strip-shaped base material BM1 extending along a rolling direction DR is first prepared. Next, the base material BM1 is transported along the transport direction toward a rolling device RE including a pair of rolling rollers RL1 and RL2 so that the rolling direction DR of the base material BM1 and the transport direction in which the base material BM1 is transported are parallel to each other.

[0068] When the base material BM1 reaches between the pair of rolling rollers RL1, RL2, the base material BM1 is rolled by the pair of rolling rollers RL1, RL2. This reduces the thickness of the base material BM1, and the base material BM1 is stretched along the conveying direction to obtain a rolled material BM2. The rolled material BM2 is wound around a core C. The rolled material BM2 may be handled in a state in which it is stretched into a strip shape without being wound around the core C. The thickness of the rolled material BM2 is, for example, 150 μm or less, and preferably 50 μm or more and 120 μm or less.

[0069] As shown in Fig. 4, in order to remove residual stress accumulated inside the rolled material BM2 formed by rolling the base material BM1, the rolled material BM2 is annealed using an annealing device AE. This results in an annealed rolled material BM3. The annealing of the rolled material BM2 is performed while pulling the rolled material BM2 along the transport direction, so it is possible to obtain a rolled material BM3 with reduced residual stress compared to the rolled material BM2 before annealing.

[0070] As described above, the material forming the base material BM1 may include any one selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. Since these metals have high hardness, in other words, are less likely to stretch than metals having lower hardness, i.e., softer metals, variations in the degree of rolling tend to occur within the base material BM1. Furthermore, variations in the degree of rolling tend to occur among a plurality of base materials BM1. Therefore, the selection conditions for the metal foil 10 formed by rolling the base material BM1 are highly effective when they include the above-mentioned condition 1.

[0071] FIG. 5 shows a schematic diagram of a process for measuring the thickness of the metal foil 10 formed through a rolling process. As shown in Fig. 5, after preparing a plurality of rolled materials BM3 obtained through rolling, the thickness of the first region for forming the spring member 20 in each rolled material BM3 is measured using a measuring device ME. As a result, at least the above-mentioned first absolute value is calculated for the first region of each rolled material BM3. Then, from among the plurality of rolled materials BM3, the rolled material BM3 that satisfies the above-mentioned first condition is selected as the metal foil 10, and the selected metal foil 10 is used to manufacture the spring member 20.

[0072] The above-mentioned first standard deviation, second standard deviation, first absolute value, and third absolute value may be calculated for the first region of each rolled material BM3. At least one of the above-mentioned conditions 2 to 4 may be added to the conditions for selecting the metal foil 10 from the rolled material BM3. That is, only one of the conditions 2 to 4 may be added to the conditions for selecting the metal foil 10 from the rolled material BM3, or two or more selected from the conditions 2 to 4 may be added. Furthermore, the measuring device ME may be a contact measuring device or a non-contact measuring device.

[0073] A length gauge, for example, can be used as the contact type measuring device. A measuring device including an irradiation unit that irradiates X-rays and a detection unit that detects fluorescent X-rays can be used as the non-contact type measuring device. When using this measuring device, first, the metal foil 10 is irradiated with X-rays using the irradiation unit, and the fluorescent X-rays emitted from the metal foil 10 are detected using the detection unit. Since the intensity of the fluorescent X-rays detected by the detection unit depends on the thickness of the metal foil 10, it is possible to determine the thickness of the metal foil 10 from the intensity of the fluorescent X-rays.

[0074] The first standard deviation, the second standard deviation, the first variance, the second variance, the first difference value, and the second difference value can be changed by changing at least one of the following: the rotation speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2. That is, only one of the rotation speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2 may be changed. Alternatively, any two or more of the rotation speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2 may be changed.

[0075] [Manufacturing method for spring components] A method for manufacturing the spring member 20 will be described with reference to FIGS. 6, when manufacturing the spring member 20, first, a first resist layer PR1 is formed on the front surface 10F of the metal foil 10, and a second resist layer PR2 is formed on the back surface 10B. Note that, although the resist layers PR1 and PR2 are formed of a positive photoresist in the example described with reference to Fig. 6 to Fig. 10, each of the resist layers PR1 and PR2 may be formed of a negative photoresist.

[0076] 7, a first photomask PM1 is placed on the first resist layer PR1, and a second photomask PM2 is placed on the second resist layer PR2. Then, the first resist layer PR1 is exposed using the first photomask PM1, and the second resist layer PR2 is exposed using the second photomask PM2.

[0077] As shown in FIG. 8, the exposed resist layers PR1, PR2 are developed, whereby a first resist mask RM1 is formed from the first resist layer PR1, and a second resist mask RM2 is formed from the second resist layer PR2.

[0078] 9, the metal foil 10 is wet-etched using resist masks RM1 and RM2. At this time, the metal foil 10 is etched from both the front surface 10F and the back surface 10B. As a result, through holes penetrating the metal foil 10 in the thickness direction are formed in the metal foil 10, and as a result, an outer frame portion 21, an inner frame portion 22 separated from the outer frame portion 21, and a spring portion 23 connecting the inner frame portion 22 to the outer frame portion 21 are formed.

[0079] At this time, since the metal foil 10 satisfies condition 1, it is easy to obtain the spring member 20 having a desired shape in the thickness direction of the metal foil 10. In addition, since the metal foil 10 satisfies condition 1, it is possible to obtain the spring member 20 in which the variation in spring width in the thickness direction of the spring member 20 is suppressed within a predetermined range without changing the wet etching conditions according to the variation in thickness of the metal foil 10. Therefore, in manufacturing the spring member 20, it is not necessary to change the wet etching conditions according to the variation in thickness, so it is also possible to eliminate errors in the combination of the variation in thickness and the wet etching conditions.

[0080] As shown in FIG. 10, the resist masks RM1 and RM2 are removed from the etched metal foil 10, and then the spring member 20 is cut out from the etched metal foil 10, thereby obtaining the spring member 20.

[0081] [Example] An example and a comparative example will be described with reference to FIGS. [Example 1] First, a base material made of titanium copper was rolled to form a rolled material. Then, the rolled material was annealed. As a result, the metal foil of Example 1 having a design thickness of 120 μm was obtained.

[0082] [Examples 2 to 8 and Comparative Examples 1 to 4] In Example 1, when rolling the base material, at least one of the rotation speed of the rolling rollers, the pressing force between the rolling rollers, the temperature of the rolling rollers, and the number of rolling rollers was changed, while the rest was kept the same as in Example 1, thereby obtaining the metal foils of Examples 2 to 8 and Comparative Examples 1 to 4.

[0083] [Evaluation method] [Thickness measurement] A method for measuring the thickness of the metal foil 10 will be described with reference to FIG.

[0084] As shown in FIG. 11, a square-shaped test metal foil 30 with a side length of 300 mm was cut out from the metal foil of each example and each comparative example. The test metal foil 30 was cut out from each metal foil so that the direction in which the first side of each test metal foil 30 extends was parallel to the rolling direction DR of the metal foil, and the direction in which the second side of each test metal foil 30 extends was perpendicular to the width direction DW of the metal foil. In each test metal foil 30, a square-shaped test area 30A including the center of the test metal foil 30 and a rectangular frame-shaped peripheral area 30B surrounding the test area 30A were set. At this time, the width W3 of the peripheral area 30B was set to 10 mm.

[0085] In addition, a first measurement area R1R having a strip shape extending along the rolling direction DR and a second measurement area R1W having a strip shape extending along the width direction DW were set in the measurement area 30A. At this time, the width W1, which is the length in the width direction DW of the first measurement area R1R, was set to 20 mm, and the width W2, which is the length in the rolling direction DR of the second measurement area R1W, was set to 20 mm.

[0086] The thickness of the metal foil was measured in all of the regions obtained by dividing the first measurement region R1R into 14 equal parts in the rolling direction DR. The thickness of the metal foil 30 for measurement was also measured in all of the regions obtained by dividing the second measurement region R1W into 14 equal parts in the width direction DW.

[0087] In each region, the thickness was measured at the point where the diagonal lines connecting the two opposing corners intersected. That is, the thickness was measured at each point located on the same straight line. For each measurement metal foil, the thickness was measured at 14 points in the rolling direction DR and 14 points in the width direction DW. However, in the region where the first measurement region R1R and the second measurement region R1W intersect, the measurement point in the rolling direction DR and the measurement point in the width direction DW are the same point, so the thickness was measured at a total of 27 points for each measurement metal foil. The measured values ​​were then rounded off to one decimal place, and the measured thickness values ​​in each region were obtained.

[0088] From these measured values, the first standard deviation, the second standard deviation, the first variance, and the second variance were calculated. In addition, a third difference value, which is a difference value obtained by subtracting the second standard deviation from the first standard deviation, and a first absolute value, which is an absolute value of the third difference value, were calculated. In addition, a fourth difference value, which is a difference value obtained by subtracting the second variance from the first variance, and a second absolute value, which is an absolute value of the fourth difference value, were calculated. In addition, a third absolute value, which is an absolute value of a difference value obtained by subtracting the second difference value from the first difference value, and a fourth absolute value, which is an absolute value of a difference value obtained by subtracting the maximum value of the thickness in the width direction DW from the maximum value of the thickness in the rolling direction DR, were calculated.

[0089] A contact-type thickness gauge (Nikon Corporation, MH-15M) was used to measure the thickness of the metal foil 30. When measuring the thickness, the plate thickness measuring device counter attached to the gauge was turned on with the gauge head in contact with the base plate, and zero-point adjustment was performed. The metal foil was then placed between the gauge head and the base plate, and the gauge head was then lowered to measure the thickness of each portion of the metal foil.

[0090] [Evaluation of etching patterns] A resist mask having a plurality of openings corresponding to the shape of the spring member 20 was formed on the front and back surfaces of each of the measurement metal foils 30, and the measurement metal foils 30 were wet-etched from both the front and back surfaces using the two resist masks. In the measurement area 30A, unit areas corresponding to one spring member 20 and having a square shape of 20 mm on each side were arranged in a lattice pattern so as to be spread out in both the rolling direction DR and the width direction DW. Therefore, in each resist mask, unit patterns corresponding to the shape of one spring member 20 were also arranged in a lattice pattern so as to be spread out in both the rolling direction DR and the width direction DW.

[0091] In the unit pattern, in the portion of the spring member 20 that forms the spring portion 23 having a folded line shape, the opening width of the resist pattern corresponding to the gap between adjacent line segments that are parallel to each other in the spring portion 23 was set to 100 μm, and the pitch of the adjacent line segments was set to 200 μm. Here, the pitch of adjacent line segments refers to the distance between center lines set for adjacent line segments that are parallel to each other in the design of the etching pattern.

[0092] In addition, multiple unit patterns were formed in each resist mask so that, when viewed in a plane facing the surface of the measurement metal foil 30, the entirety of one unit pattern in the resist mask located on the surface of the measurement metal foil 30 overlaps the entirety of one unit pattern in the resist mask located on the back surface of the measurement metal foil 30.

[0093] Using such a resist mask, a plurality of etching patterns corresponding to the shape of the spring member 20 were formed in the measurement metal foil 30. In the etching patterns, the design value of the spring width of the spring portion 23 in a plan view was set to 30 μm.

[0094] The spring portion 23 of the spring member 20 present in each of the etched metal foils for measurement 30 was embedded in a synthetic resin. Then, the embedded spring portion 23 was cut using a microtome to expose a cross section of the spring portion 23 in a plane perpendicular to the direction in which the line segments included in the spring portion extend.

[0095] The spring width was measured at the following positions in the cross section of the spring portion 23. That is, in the spring portion 23, the spring width on the front surface of the metal foil 30 for measurement, the spring width on the back surface of the metal foil 30 for measurement, and the spring width on three planes sandwiched between the front surface and the back surface of the metal foil 30 for measurement among the planes dividing the spring portion 23 into four equal parts in the thickness direction were measured. That is, when the depth on the front surface of the metal foil 30 for measurement was set to 0 μm, the spring width at a depth of 0 μm, the spring width at a depth of about 30 μm, the spring width at a depth of about 60 μm, the spring width at a depth of about 90 μm, and the spring width at a depth of about 120 μm were measured in the etching pattern. When measuring the spring width of the spring portion 23, a digital microscope (Keyence Corporation, VHX-7000) was used, and the magnification of the objective lens in the digital microscope was set to 200 times.

[0096] In addition, for the etching patterns obtained from the measurement metal foils 30 of each example and each comparative example, the first standard value, the standard deviation of the spring width, the second standard value, the percentage of 3σ relative to the average spring width, and the variance of the spring width were calculated.

[0097] For each unit pattern included in the measurement metal foil 30, the spring width was measured at the above-mentioned five locations in the thickness direction for all springs included in the spring portion 23. Then, the maximum value and the minimum value were identified for each spring, a difference value was calculated by subtracting the minimum value from the maximum value, and the average value of the spring width was calculated. Next, the average value of the maximum values ​​was calculated from the identified maximum values ​​for all springs, and the average value was set as the maximum value of the spring width for the measurement metal foil 30. Also, the average value of the minimum values ​​was calculated from the identified minimum values ​​for all springs, and the minimum value was set as the minimum value of the spring width for the measurement metal foil 30. Also, the average value of the difference values ​​calculated for all springs was calculated, and the average value was set as the difference value for the measurement metal foil 30. Also, the average value of the average values ​​calculated for all springs was calculated, and the average value was set as the average value for the measurement metal foil 30.

[0098] In addition, the first standard value, the standard deviation of the spring width, the second standard value, and the percentage of 3σ relative to the average value of the spring width were calculated for the etching patterns obtained from the measurement metal foils 30 of each Example and Comparative Example. When calculating the percentage of 3σ relative to the average value of the spring width, the average value set for each measurement metal foil 30 was used. The first standard value is the percentage of the difference value of the spring width relative to the design value of the spring width. The difference value set for each measurement metal foil 30 was used to calculate the first standard value. The second standard value is the percentage of the standard deviation of the spring width relative to the design value of the spring width.

[0099] When calculating the standard deviation of the spring width, first, the standard deviation of the spring width was calculated from the thickness measured at five points for each spring. Next, the average value of the standard deviations calculated for all the springs was calculated, and the average value was set as the standard deviation of the spring width for the measurement metal foil 30. In addition, the standard deviation set for each measurement metal foil 30 was used to calculate the second standard value.

[0100] When calculating the variance of the spring width, first, the variance of the spring width was calculated from the thickness measured at five points for each spring. Next, the average value of the variances calculated for all the springs was calculated, and the average value was set as the variance of the spring width for the measurement metal foil 30.

[0101] [Evaluation Results] The evaluation results for the thickness of the metal foil 30 to be measured and the spring width of the etching pattern will be described with reference to FIGS.

[0102] 12 shows the results of measuring the thickness of each of the test metal foils 30 and the results of measuring the spring width of an etching pattern formed by wet etching each of the test metal foils 30. In FIG. 12, the first absolute value is the absolute value of the difference value obtained by subtracting the second standard deviation from the first standard deviation. Also, the fourth absolute value is the absolute value of the difference value obtained by subtracting the maximum thickness value in the width direction DW from the maximum thickness value in the rolling direction DR.

[0103] 12, the first standard deviation was found to be 0.313 μm in Example 1, 0.291 μm in Example 2, 0.389 μm in Example 3, and 0.261 μm in Example 4. The first standard deviation was also found to be 0.516 μm in Example 5, 0.421 μm in Example 6, 0.532 μm in Example 7, and 0.524 μm in Example 8. The first standard deviation was also found to be 0.766 μm in Comparative Example 1, 0.571 μm in Comparative Example 2, 0.566 μm in Comparative Example 3, and 0.498 μm in Comparative Example 4.

[0104] The second standard deviation was found to be 0.243 μm in Example 1, 0.303 μm in Example 2, 0.332 μm in Example 3, and 0.184 μm in Example 4. The second standard deviation was found to be 0.447 μm in Example 5, 0.311 μm in Example 6, 0.420 μm in Example 7, and 0.412 μm in Example 8. The second standard deviation was found to be 0.260 μm in Comparative Example 1, 0.218 μm in Comparative Example 2, 0.221 μm in Comparative Example 3, and 0.307 μm in Comparative Example 4.

[0105] Thereby, it was confirmed that the third difference value was 0.069 μm in Example 1, −0.012 μm in Example 2, 0.057 μm in Example 3, and 0.077 μm in Example 4. It was also confirmed that the third difference value was 0.068 μm in Example 5, 0.110 μm in Example 6, 0.112 μm in Example 7, and 0.111 μm in Example 8. It was also confirmed that the third difference value was 0.507 μm in Comparative Example 1, 0.353 μm in Comparative Example 2, 0.346 μm in Comparative Example 3, and 0.191 μm in Comparative Example 4.

[0106] It was also found that the first absolute value was 0.069 μm in Example 1, 0.012 μm in Example 2, 0.057 μm in Example 3, and 0.077 μm in Example 4. It was also found that the first absolute value was 0.068 μm in Example 5, 0.110 μm in Example 6, 0.112 μm in Example 7, and 0.111 μm in Example 8. It was also found that the first absolute value was 0.507 μm in Comparative Example 1, 0.353 μm in Comparative Example 2, 0.346 μm in Comparative Example 3, and 0.191 μm in Comparative Example 4.

[0107] Thus, in the measurement metal foils 30 of Examples 1 to 8, the first absolute value was 0.15 μm or less, while in the measurement metal foils 30 of Comparative Examples 1 to 4, the first absolute value was found to be greater than 0.15 μm. In particular, in the measurement metal foils 30 of Examples 1 to 8, the first absolute value was found to be 0.012 μm or more and 0.112 μm or less, while in the measurement metal foils 30 of Comparative Examples 1 to 4, the first absolute value was found to be 0.191 μm or more and 0.507 μm or less. In addition, in the measurement metal foils 30 of Examples 1, 3 to 8, and Comparative Examples 1 to 4, the first standard deviation was found to be greater than the second standard deviation, while in Example 2, the first standard deviation was found to be smaller than the second standard deviation.

[0108] The first dispersion is 0.098 μm in Example 1. 2 In Example 2, it is 0.085 μm 2 In Example 3, it is 0.151 μm 2 In Example 4, it is 0.068 μm 2 It was found that the first dispersion was 0.266 μm in Example 5. 2 In Example 6, it is 0.177 μm 2 In Example 7, it is 0.283 μm 2 In Example 8, it is 0.274 μm 2 It was found that the first dispersion was 0.587 μm in Comparative Example 1.2 In Comparative Example 2, it is 0.326 μm 2 In Comparative Example 3, it is 0.321 μm 2 In Comparative Example 4, it is 0.248 μm 2 It was recognized that.

[0109] The second dispersion is 0.059 μm in Example 1. 2 In Example 2, it is 0.092 μm 2 In Example 3, it is 0.110 μm 2 In Example 4, it is 0.034 μm 2 The second dispersion was found to be 0.200 μm in Example 5. 2 In Example 6, it is 0.096 μm 2 In Example 7, it is 0.176 μm 2 In Example 8, it is 0.170 μm 2 It was found that the second dispersion was 0.067 μm in Comparative Example 1. 2 In Comparative Example 2, it is 0.048 μm 2 In Comparative Example 3, it is 0.049 μm 2 In Comparative Example 4, it is 0.095 μm 2 It was recognized that.

[0110] As a result, the fourth difference value is 0.039 μm in Example 1. 2 In Example 2, it is −0.007 μm 2 In Example 3, it is 0.041 μm 2 In Example 4, it is 0.034 μm 2 It was found that the fourth difference value was 0.066 μm in Example 5. 2 In Example 6, it is 0.081 μm 2 In Example 7, it is 0.107 μm 2 In Example 8, it is 0.104 μm 2 It was also found that the fourth difference value was 0.520 μm in Comparative Example 1. 2 In Comparative Example 2, it is 0.278 μm 2In Comparative Example 3, it is 0.272 μm 2 In Comparative Example 4, it is 0.154 μm 2 It was recognized that.

[0111] The second absolute value is 0.039 μm in Example 1. 2 In Example 2, it is 0.007 μm 2 In Example 3, it is 0.041 μm 2 In Example 4, it is 0.034 μm 2 It was found that the second absolute value was 0.066 μm in Example 5. 2 In Example 6, it is 0.081 μm 2 In Example 7, it is 0.107 μm 2 In Example 8, it is 0.104 μm 2 It was also found that the second absolute value was 0.520 μm in Comparative Example 1. 2 In Comparative Example 2, it is 0.278 μm 2 In Comparative Example 3, it is 0.272 μm 2 In Comparative Example 4, it is 0.154 μm 2 Thus, in the measurement metal foils 30 of Examples 1 to 8, the second absolute value was 0.15 μm 2 or less, while in the measurement metal foils 30 of Comparative Examples 1 to 4, the second absolute value is 0.15 μm 2 In particular, in the measurement metal foils 30 of Examples 1 to 8, the second absolute value was found to be greater than 0.007 μm 2 More than 0.107μm 2 or less, while the second absolute value in the measurement metal foils 30 of Comparative Examples 1 to 4 is 0.154 μm 2 More than 0.520μm 2 It was found that:

[0112] It was also found that the third absolute value was 0.2 μm in Example 1, 0 μm in Example 2, 0.3 μm in Example 3, and 0.3 μm in Example 4. It was also found that the third absolute value was 0.5 μm in Example 5, 0.4 μm in Example 6, 0.2 μm in Example 7, and 0.4 μm in Example 8. It was also found that the third absolute value was 1.6 μm in Comparative Example 1, 1.2 μm in Comparative Example 2, 1.2 μm in Comparative Example 3, and 0.9 μm in Comparative Example 4.

[0113] In addition, the fourth absolute value was found to be 0 μm in Example 1, 0 μm in Example 2, 0.4 μm in Example 3, and 0 μm in Example 4. The fourth absolute value was found to be 0.8 μm in Example 5, 0.5 μm in Example 6, 0.4 μm in Example 7, and 0.6 μm in Example 8. The fourth absolute value was found to be 1.5 μm in Comparative Example 1, 1.1 μm in Comparative Example 2, 0.2 μm in Comparative Example 3, and 0.9 μm in Comparative Example 4.

[0114] On the other hand, it was confirmed that the difference in spring width was 8.4 μm in Example 1, 8.4 μm in Example 2, 8.2 μm in Example 3, and 7.0 μm in Example 4. It was also confirmed that the difference in spring width was 7.5 μm in Example 5, 9.1 μm in Example 6, 8.4 μm in Example 7, and 9.7 μm in Example 8. It was also confirmed that the difference in spring width was 12.5 μm in Comparative Example 1, 13.7 μm in Comparative Example 2, 11.3 μm in Comparative Example 3, and 14.3 μm in Comparative Example 4.

[0115] In addition, it was confirmed that the first standard value was 27.9% in Example 1, 28.0% in Example 2, 27.4% in Example 3, and 23.1% in Example 4. In addition, it was confirmed that the first standard value was 24.9% in Example 5, 30.3% in Example 6, 28.1% in Example 7, and 32.3% in Example 8. It was confirmed that the first standard value was 41.6% in Comparative Example 1, 45.6% in Comparative Example 2, 37.6% in Comparative Example 3, and 47.5% in Comparative Example 4.

[0116] The standard deviation of the spring width was found to be 2.0 μm in Example 1, 1.7 μm in Example 2, 1.9 μm in Example 3, and 1.4 μm in Example 4. The standard deviation of the spring width was found to be 1.4 μm in Example 5, 1.9 μm in Example 6, 2.0 μm in Example 7, and 2.1 μm in Example 8. The standard deviation of the spring width was found to be 2.5 μm in Comparative Example 1, 2.6 μm in Comparative Example 2, 2.2 μm in Comparative Example 3, and 2.6 μm in Comparative Example 4.

[0117] The second standard value was found to be 6.6% in Example 1, 5.7% in Example 2, 6.3% in Example 3, and 4.7% in Example 4. The second standard value was found to be 4.7% in Example 5, 6.3% in Example 6, 6.6% in Example 7, and 7.1% in Example 8. The second standard value was found to be 8.2% in Comparative Example 1, 8.5% in Comparative Example 2, 7.4% in Comparative Example 3, and 8.5% in Comparative Example 4.

[0118] The percentage of 3σ relative to the average value of the spring width was found to be 17.8% in Example 1, 16.0% in Example 2, 18.3% in Example 3, and 13.0% in Example 4. The percentage of 3σ relative to the average value of the spring width was found to be 13.0% in Example 5, 18.1% in Example 6, 18.3% in Example 7, and 18.8% in Example 8. The percentage of 3σ relative to the average value of the spring width was found to be 24.8% in Comparative Example 1, 26.4% in Comparative Example 2, 23.5% in Comparative Example 3, and 22.0% in Comparative Example 4.

[0119] The spring width variance is 3.9 μm in Example 1. 2 In Example 2, it is 2.9 μm 2 In Example 3, it is 3.6 μm 2 In Example 4, it is 2.0 μm 2 The spring width dispersion was found to be 2.0 μm in Example 5. 2 In Example 6, it is 3.6 μm 2 In Example 7, it is 4.0 μm 2 In Example 8, it is 4.5 μm 2 It was found that the spring width dispersion was 6.0 μm in Comparative Example 1. 2 In Comparative Example 2, it is 6.5 μm 2 In Comparative Example 3, it is 4.9 μm 2 In Comparative Example 4, it is 6.6 μm 2 It was recognized that.

[0120] Thus, it was found that the first standard value, standard deviation, second standard value, percentage of 3σ to the average value, and variance were all smaller in the metal foils for spring members of Examples 1 to 8 than in the metal foils for spring members of Comparative Examples 1 to 4. Therefore, it can be said that the metal foils for spring members of Examples 1 to 8 have less variation in the spring width in the thickness direction than the metal foils for spring members of Comparative Examples 1 to 4.

[0121] FIG. 13 is a graph showing the relationship between the first absolute value and the difference value of the spring width. As shown in Fig. 13, when the first absolute value is 0.15 µm or less, the difference in the spring width of the etching pattern is found to be within the range of 6.0 µm to 10.0 µm. On the other hand, when the first absolute value is greater than 0.15 µm, the difference in the spring width of the etching pattern is found to exceed 11 µm. Thus, it is found that, with the first absolute value, the variation in the spring width of the etching pattern varies greatly with the boundary at 0.15 µm.

[0122] FIG. 14 is a graph showing the relationship between the second absolute value and the difference value of the spring width. As shown in FIG. 14, the second absolute value is 0.15 μm 2 When the second absolute value is 0.15 μm or less, the difference in the spring width of the etching pattern is found to be within the range of 6.0 μm to 10.0 μm. 2 It was found that the difference in the spring width of the etched pattern exceeded 11 μm when the second absolute value was greater than 0.15 μm. 2 It was found that the variation in the spring width of the etching pattern differed greatly with respect to the boundary.

[0123] FIG. 15 is a graph showing the relationship between the third absolute value and the difference value of the spring width. As shown in Fig. 13, when the third absolute value is 0.8 µm or less, the difference in the spring width of the etching pattern is found to be within the range of 6.0 µm to 10.0 µm. In contrast, when the third absolute value is greater than 0.8 µm, the difference in the spring width of the etching pattern is found to exceed 11 µm. Thus, with the third absolute value, it is found that the variation in the spring width of the etching pattern varies greatly with the boundary at 0.8 µm.

[0124] As described above, according to one embodiment of the metal foil for a spring member, the manufacturing method for the metal foil for a spring member, and the spring member for electronic devices, the following effects can be obtained. (1) Because the metal foil 10 satisfies the condition 1, the variation in thickness of the metal foil 10 is suppressed. Therefore, in the spring member 20 formed by wet etching the metal foil 10, the variation in the spring width in the thickness direction is suppressed.

[0125] (2) Since the metal foil 10 satisfies at least one of the conditions 2 to 4, the variation in thickness of the metal foil 10 is suppressed. Therefore, the variation in width of the spring member 20 in the thickness direction is suppressed.

[0126] (3) Since the metal foil 10 can have high hardness, the durability of the spring member 20 formed from the metal foil 10 can be increased. [Explanation of symbols]

[0127] 10...Metal foil for spring components 10R1…1st area 20...Spring member

Claims

1. A metal foil for manufacturing spring components, The metal foil for the spring member is a rolled material, It has a square shape with a side length of 280 mm and includes a first region for forming the spring member, In the first region, the absolute value of the difference obtained by subtracting the thickness dispersion in the width direction perpendicular to the rolling direction from the thickness dispersion in the rolling direction is 0.15 μm. ２ The following: The ratio of the difference between the maximum and minimum thicknesses of the metal foil for the spring member to the average thickness of the metal foil for the spring member is 3% or less. Metal foil for spring components.

2. In the first region, the difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The metal foil for spring members according to claim 1.

3. In the first region, the difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following is The metal foil for spring members according to claim 1.

4. In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The metal foil for spring members according to claim 1.

5. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following is The metal foil for spring members according to claim 1.

6. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The metal foil for spring members according to claim 1.

7. In the first region, The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following: In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The metal foil for spring members according to claim 1.

8. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following: The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The metal foil for spring members according to claim 1.

9. The metal foil for the spring member includes any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. Metal foil for spring members according to any one of claims 1 to 8.

10. A method for manufacturing metal foil for spring members, for manufacturing spring members, Rolling the base material, This includes preparing a plurality of rolled materials obtained by rolling the base material, and then selecting the metal foil for the spring member from the plurality of rolled materials, In the rolled material, the region having a square shape with a side length of 280 mm is the first region where the spring member is formed. In selecting the metal foil for the spring member, from the plurality of rolled materials, the absolute value of the difference obtained by subtracting the thickness dispersion in the width direction perpendicular to the rolling direction from the thickness dispersion in the rolling direction in the first region is 0.15 μm. ２ The rolled material described below is selected as metal foil for the spring member, The ratio of the difference between the maximum and minimum thicknesses of the metal foil for the spring member to the average thickness of the metal foil for the spring member is 3% or less. A method for manufacturing metal foil for spring components.

11. The selection of the metal foil for the spring member is The selection criteria for the metal foil for the spring member include the condition that, in the first region, the difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is between -0.012 μm and 0.15 μm. The method for manufacturing a metal foil for a spring member according to claim 10.

12. The selection of the metal foil for the spring member is The conditions for selecting the metal foil for the spring member are that, in the first region, the difference value obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ This includes the following: The method for manufacturing a metal foil for a spring member according to claim 10.

13. In the first region, The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The selection of the metal foil for the spring member is The conditions for selecting the metal foil for the spring member are: The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The method for manufacturing a metal foil for a spring member according to claim 10.

14. The selection of the metal foil for the spring member is The conditions for selecting the metal foil for the spring member are that, in the first region, the difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less, In the first region, the difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ This includes the following: The method for manufacturing a metal foil for a spring member according to claim 10.

15. In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The method for manufacturing the metal foil for the spring member is as follows: The conditions for selecting the metal foil for the spring member are that, in the first region, the difference value obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less, The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The method for manufacturing a metal foil for a spring member according to claim 10.

16. In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The selection of the metal foil for the spring member is Among the conditions for selecting the metal foil for the spring member, in the first region, the difference value obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm ２ or less, and The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The method for manufacturing a metal foil for a spring member according to claim 10.

17. In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The selection of the metal foil for the spring member is In the first region, the difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. In the first region, the difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following conditions apply, and The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. The method for manufacturing a metal foil for a spring member according to claim 10.

18. The metal foil for the spring member includes any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. A method for manufacturing a metal foil for a spring member according to any one of claims 10 to 17.

19. A method for manufacturing a spring member for electronic equipment using metal foil for spring members, The metal foil for the spring member is a rolled material, It has a square shape with a side length of 280 mm and includes a first region for forming the spring member, In the first region, the absolute value of the difference obtained by subtracting the thickness distribution in the width direction perpendicular to the rolling direction from the thickness distribution in the rolling direction of the metal foil for the spring member is 0.15 μm. ２ The following: The ratio of the difference between the maximum and minimum thicknesses of the metal foil for the spring member to the average thickness of the metal foil for the spring member is 3% or less. A method for manufacturing spring components for electronic devices.

20. In the first region, the difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. A method for manufacturing a spring member for electronic equipment according to claim 19.

21. In the first region, the difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following is A method for manufacturing a spring member for electronic equipment according to claim 19.

22. In the first region, the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction is the first difference value, and the difference value obtained by subtracting the minimum value from the maximum value of the thickness in the width direction is the second difference value. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. A method for manufacturing a spring member for electronic equipment according to claim 19.

23. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following is A method for manufacturing a spring member for electronic equipment according to claim 19.

24. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. A method for manufacturing a spring member for electronic equipment according to claim 19.

25. In the first region, The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following: The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. A method for manufacturing a spring member for electronic equipment according to claim 19.

26. In the first region, The difference obtained by subtracting the standard deviation of the thickness in the width direction from the standard deviation of the thickness in the rolling direction is -0.012 μm or more and 0.15 μm or less. The difference obtained by subtracting the dispersion of the thickness in the width direction from the dispersion of the thickness in the rolling direction is 0.15 μm. ２ The following: The first difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the rolling direction, and the second difference value is the difference obtained by subtracting the minimum value from the maximum value of the thickness in the width direction. The absolute value of the difference obtained by subtracting the second difference value from the first difference value is 0.8 μm or less. A method for manufacturing a spring member for electronic equipment according to claim 19.

27. The metal foil for the spring member includes any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. A method for manufacturing a spring member for electronic equipment according to any one of claims 19 to 26.

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