Metal light shielding plate base material, metal light shielding plate, camera module, electronic apparatus, and metal light shielding plate manufacturing method

Abstract

To provide a metal light shielding plate base material capable of ensuring light shielding performance of a metal light shielding plate of a camera module.SOLUTION: The three-dimensional surface roughness Sa of a surface 10MR of a metal light shielding plate base material 10M used for a metal light shielding plate is 0.142 μm or more in a 50-time visual field. The three-dimensional surface roughness Sz of the surface 10MR is 2.666 μm or more in the 50-time visual field.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metal light shading plate substrate, a metal light shading plate, a camera module, an electronic device, and a method for manufacturing a metal light shading plate. [Background technology]

[0002] Camera modules installed in electronic devices such as smartphones use a component called a light shield that functions as a diaphragm for blocking external light. The light shield has through holes that penetrate the thickness direction of the plate to allow only necessary external light to pass through. The light shield suppresses image defects such as ghosts and flares that occur in images when unnecessary external light (e.g. scattered light) enters the lens or imaging element (image sensor such as CCD or CMOS).

[0003] Patent Document 1 discloses a metallic light shielding plate (metal light shielding plate) that can obtain the desired light shielding performance even when formed thin. When manufacturing the metal light shielding plate, through holes are formed in the metal light shielding plate substrate (metal foil). When forming the through holes in the metal light shielding plate substrate, resist layers are provided on both sides of the metal light shielding plate substrate, patterns corresponding to the through holes are formed in each resist layer, and the metal light shielding plate substrate is etched from both sides using the resist layers with the patterns formed thereon as a mask. This allows the through holes to be formed in the metal light shielding plate substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-113920 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a through hole is simply formed in a metal light shielding plate substrate by using a resist layer without any special measures, there is a problem that the edge of the through hole becomes uneven and the size (e.g., diameter) of the through hole varies greatly. In this case, there is a problem that unnecessary external light is incident on the lens or imaging element in the camera module, making it impossible to ensure the light shielding performance of the light shielding plate.

[0006] The present invention aims to provide a metal light-shielding plate substrate, a metal light-shielding plate, a camera module, an electronic device, and a method for manufacturing a metal light-shielding plate that can ensure the light-shielding performance of the metal light-shielding plate. [Means for solving the problem]

[0007] A first aspect of the present invention is a substrate used for a metal light shading plate, the substrate having a three-dimensional surface roughness Sa of 0.142 μm or more at a 50x magnification and a three-dimensional surface roughness Sz of 2.666 μm or more at a 50x magnification.

[0008] A second aspect of the present invention is a metal light-shielding plate using the metal light-shielding plate substrate described in the first aspect.

[0009] A third aspect of the present invention is a camera module using the metal light shielding plate according to the second aspect.

[0010] A fourth aspect of the present invention is an electronic device using the camera module according to the third aspect.

[0011] A fifth aspect of the present invention is a method for manufacturing a metal light shading plate, comprising: preparing a metal light shading plate substrate configured to have a dry film resist attached thereto and having a surface on which an opening is formed by etching using the patterned dry film resist, the three-dimensional surface roughness Sa of the surface being 0.142 μm or more in a 50x field of view and the three-dimensional surface roughness Sz of the surface being 2.666 μm or more in a 50x field of view; arranging the dry film resist on the surface; forming a through hole in the dry film resist for forming a recess in the metal light shading plate substrate, the recess being recessed along the thickness direction of the metal light shading plate substrate and having the opening on the surface; forming the recess in the metal light shading plate substrate via the dry film resist; and removing the dry film resist from the metal light shading plate substrate in which the recess has been formed. Effect of the Invention

[0012] According to the present invention, the light-shielding performance of the metal light-shielding plate can be ensured. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view showing a metal light shielding plate substrate according to one embodiment of the present invention; [Diagram 2] 1 is a plan view showing a metal light shielding plate according to an embodiment of the present invention; [Diagram 3] 3 is a cross-sectional view showing a schematic view of a main part of the metal light-shielding plate of FIG. 2. [Figure 4] 11A to 11C are diagrams for explaining a manufacturing method of a metal light shielding plate. [Diagram 5] 11A to 11C are diagrams for explaining a manufacturing method of a metal light shielding plate. [Figure 6] 11A to 11C are diagrams for explaining a manufacturing method of a metal light shielding plate. [Figure 7] 11A to 11C are diagrams for explaining a manufacturing method of a metal light shielding plate. [Figure 8] 11A to 11C are diagrams for explaining a manufacturing method of a metal light shielding plate. [Figure 9] 4 is a diagram showing an example of a camera module including the metal light shielding plate of FIGS. [Figure 10] This is an image showing an example in which the edges of the holes in the metal light-shielding plate are free of wobble. [Figure 11] 13 is an image showing an example in which the edges of holes in a metal light-shielding plate are uneven. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1 to 11, an embodiment of a metal light-shielding plate substrate, a metal light-shielding plate, a camera module, an electronic device, and a method for manufacturing a metal light-shielding plate will be described. Below, the metal light-shielding plate substrate, the metal light-shielding plate, the method for manufacturing a metal light-shielding plate, the camera module, and examples will be described in order.

[0015] [Metal light shielding plate base material] The metal light shading plate substrate 10M shown in FIG. 1 is used in the metal light shading plate 10 (see FIG. 2 and FIG. 3) described below. The metal light shading plate substrate 10M is a metal layer that spreads along one surface. The metal light shading plate substrate 10M is made of a rolled material having a thickness of 10 μm or more and 50 μm or less. The metal light shading plate substrate 10M has a first surface 10MR (front surface) and a second surface 10MF. The first surface 10MR and the second surface 10MF are surfaces that face opposite each other in the thickness direction of the metal light shading plate substrate 10M.

[0016] The first surface 10MR is an example of a surface configured to have a resist disposed thereon, specifically, an example of a surface configured to have a first dry film resist RR (dry film resist) attached thereto. The three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more at a 50x magnification, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more at a 50x magnification. The three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more at a 150x magnification, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more at a 150x magnification.

[0017] The second surface 10MF is an example of a surface configured to have a resist disposed thereon, specifically, an example of a surface configured to have a second dry film resist RF (dry film resist) attached thereto. The three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more at a 50x magnification, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more at a 50x magnification. The three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more at a 150x magnification, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more at a 150x magnification.

[0018] The above-mentioned three-dimensional surface roughness Sa and three-dimensional surface roughness Sz are values ​​measured by a method conforming to ISO 25178. The three-dimensional surface roughness Sa is the arithmetic mean height Sa in a defined region having a predetermined area, and the three-dimensional surface roughness Sz is the maximum height Sz in a defined region having a predetermined area.

[0019] The material of the metal light shielding plate base material 10M may be, for example, stainless steel (SUS), that is, an alloy mainly composed of iron and chromium. The material of the metal light shielding plate base material 10M may be other metal materials or alloy materials.

[0020] According to the above-mentioned metal light shielding plate substrate 10M, the three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more in a 50-fold visual field, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more in a 50-fold visual field. Therefore, a gap is unlikely to be formed between the first surface 10MR and the first dry film resist RR attached to the first surface 10MR, and the adhesion at the interface between the first surface 10MR of the metal light shielding plate substrate 10M and the first dry film resist RR can be improved. In addition, in the above-mentioned metal light shielding plate substrate 10M, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more in a 150-fold visual field, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more in a 150-fold visual field. Therefore, it is possible to reliably increase the adhesion at the interface between the first surface 10MR of the metal light shielding plate substrate 10M and the first dry film resist RR.

[0021] Furthermore, according to the above-mentioned metal light shielding plate substrate 10M, the three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more in a 50-fold visual field, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more in a 50-fold visual field. Therefore, in addition to the first surface 10MR, the adhesion between the metal light shielding plate substrate 10M and the second dry film resist RF can be increased on the second surface 10MF as well. In addition, in the above-mentioned metal light shielding plate substrate 10M, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more at a magnification of 150, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more at a magnification of 150. Therefore, the adhesion between the metal light shielding plate substrate 10M and the second dry film resist RF on the second surface 10MF can be reliably improved.

[0022] Furthermore, when the above-mentioned metal light-shielding plate substrate 10M is made of stainless steel, the adhesion between the metal light-shielding plate substrate 10M and the first dry film resist RR and the second dry film resist RF can be effectively improved by setting the three-dimensional surface roughness Sa, Sz of the first surface 10MR and the second surface 10MF of the metal light-shielding plate substrate 10M as described above.

[0023] [Metal light shielding plate] The metal light shading plate 10 shown in FIG. 2 and FIG. 3 is manufactured using the above-mentioned metal light shading plate substrate 10M. The metal light shading plate 10 has a first surface 10R (surface), a second surface 10F, and a hole 10H. The first surface 10R of the metal light shading plate 10 corresponds to the first surface 10MR of the metal light shading plate substrate 10M. The second surface 10F of the metal light shading plate 10 corresponds to the second surface 10MF of the metal light shading plate substrate 10M. The hole 10H penetrates between the second surface 10F and the first surface 10R. The thickness T of the metal light shading plate 10 is 10 μm or more and 50 μm or less, similar to the metal light shading plate substrate 10M. In the metal light shading plate 10, the second surface 10F is the surface located on the light incident side.

[0024] The first surface 10R, the second surface 10F, and the side surfaces of the holes 10H of the metal light shading plate 10 may be covered with an anti-reflection film (not shown). The anti-reflection film has a lower reflectance than the metal forming the metal light shading plate 10, and has the function of absorbing a portion of the light irradiated onto the anti-reflection film. Note that the anti-reflection film covering the metal light shading plate 10 does not need to completely eliminate the reflection of light on the metal light shading plate 10.

[0025] 2, the metal light shielding plate 10 is formed in a circular shape in a plan view. The hole 10H is also formed in a circular shape in a plan view.

[0026] As shown in FIG. 3, the hole 10H includes a first recess 10H1 and a second recess 10H2. The first recess 10H1 has a first opening H1R in the first surface 10R and is a recess having a shape tapering from the first surface 10R to the second surface 10F. The second recess 10H2 has a second opening H2F in the second surface 10F that is larger than the first opening H1R. The second recess 10H2 has a shape tapering from the second surface 10F to the first surface 10R and is connected to the first recess 10H1. Of the openings of the first recess 10H1, the opening on the opposite side to the first opening H1R is a central opening HC having a circular shape.

[0027] In the thickness direction of the metal light shielding plate 10, the depth dimension of the second recess 10H2 is greater than the depth dimension of the first recess 10H1. The central opening HC is located near the first opening H1R. The hole 10H is formed in a tapered shape that becomes smaller from the first surface 10R toward the second surface 10F and from the second surface 10F toward the first surface 10R.

[0028] In this embodiment, in a cross section along a plane perpendicular to the second surface 10F, the side surface (inner surface) of the second recess 10H2 is arc-shaped, and the center of curvature of the side surface of the second recess 10H2 is located outside the metal light shading plate 10. In addition, the side surface (inner surface) of the first recess 10H1 is arc-shaped, and the center of curvature of the side surface of the first recess 10H1 is located outside the metal light shading plate 10.

[0029] In the metal light-shielding plate 10, the diameter of the first recess 10H1 at the first opening H1R is a first diameter DH1, and the diameter of the second recess 10H2 at the second opening H2F is a second diameter DH2. In this embodiment, since the central opening HC is located near the first opening H1R, the diameter of the central opening HC is approximately equal to the first diameter DH1 of the first recess 10H1.

[0030] The first diameter DH1 is a value set according to the camera module in which the metal light shading plate 10 is mounted. When the metal light shading plate 10 is mounted, for example, in a camera module of a smartphone, the first diameter DH1 may be 0.4 mm or more and 1.0 mm or less. When the metal light shading plate 10 is mounted, for example, in an in-vehicle camera, the first diameter DH1 may be 2.0 mm or more and 7.0 mm or less. The percentage (DH1 / DH2×100) of the first diameter DH1 to the second diameter DH2 may be, for example, 80% or more and 99% or less.

[0031] [Method of manufacturing metal light shielding plate] Next, an example of a method for manufacturing a metal light shading plate 10 using the metal light shading plate substrate 10M will be described with reference to FIGS. In manufacturing the metal light shading plate 10, a metal light shading plate substrate 10M (FIG. 1) is prepared. In preparing the metal light shading plate substrate 10M, first, as shown in FIG. 4, a base material 15a made of stainless steel (SUS) and extending along one direction, that is, an extension direction D1, is prepared. Next, the base material 15a is transported toward a rolling device 50 equipped with a pair of rolling rollers 51, 52 so that the extension direction D1 of the base material 15a and the transport direction D2 in which the base material 15a is transported are parallel to each other.

[0032] When the base material 15a reaches between the pair of rolling rollers 51, 52, the base material 15a is rolled by the pair of rolling rollers 51, 52. This reduces the thickness of the base material 15a, and the base material 15a is stretched along the conveying direction D2, thereby obtaining a rolled material 15 as the metal light shading plate substrate 10M. In FIG. 4, the rolled material 15 is wound around the core C, but the rolled material 15 may be handled in a state where it is stretched into a strip shape without being wound around the core C, for example. The thickness of the rolled material 15 is, for example, 10 μm or more and 50 μm or less.

[0033] Although not shown, the rolled material 15 may be annealed to remove residual stress accumulated inside the rolled material 15 formed by rolling the base material 15a. In this case, it is possible to obtain the rolled material 15 with reduced residual stress.

[0034] In the metal light shielding plate substrate 10M made of the rolled material 15 obtained as described above, the three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more in a 50-fold visual field, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more in a 50-fold visual field. Also, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more in a 150-fold visual field, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more in a 150-fold visual field. Furthermore, the three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more in a 50-fold visual field, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more in a 50-fold visual field. In addition, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more at a 150-fold magnification, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more at a 150-fold magnification. The above-mentioned three-dimensional surface roughness Sa and three-dimensional surface roughness Sz of the metal light-shielding plate substrate 10M can be obtained, for example, by transferring the surfaces of the rolling rollers 51, 52 to the base material 15a when rolling the base material 15a.

[0035] After preparing the metal light shading plate substrate 10M, a first dry film resist RR is placed on a first surface 10MR of the metal light shading plate substrate 10M as shown in Fig. 5. A second dry film resist RF is placed on a second surface 10MF of the metal light shading plate substrate 10M. The dry film resists RR and RF may be negative resists or positive resists.

[0036] As shown in FIG. 6, through holes RRh, RFh are formed in the dry film resists RR, RF by exposing and developing the dry film resists RR, RF, thereby obtaining patterned dry film resists RR, RF. More specifically, a first through hole RRh is formed in the first dry film resist RR by exposing and developing the first dry film resist RR. The first through hole RRh is a hole in the first dry film resist RR for forming a first recess 10H1 (see FIGS. 2 and 7) having a first opening H1R in the first surface 10MR. Furthermore, by exposing and developing the second dry film resist RF, second through holes RFh are formed in the second dry film resist RF. The second through holes RFh are holes in the second dry film resist RF for forming the second recesses 10H2 (see FIGS. 2 and 8) having the second openings H2F in the second surface 10MF.

[0037] As shown in Fig. 7, a first recess 10H1 is formed in the metal light shading plate substrate 10M via a first dry film resist RR arranged on the first surface 10MR, the first recess 10H1 being recessed along the thickness direction of the metal light shading plate substrate 10M and having a first opening H1R on the first surface 10MR. The first recess 10H1 has a shape that tapers from the first surface 10MR toward the second surface 10MF. The first recess 10H1 is the first recess 10H1 that the metal light shading plate 10 has.

[0038] When forming the first recess 10H1, the metal light shielding plate substrate 10M is etched using an etching solution capable of etching the metal light shielding plate substrate 10M. Before etching the metal light shielding plate substrate 10M, the second dry film resist RF is covered with a second surface protective film PMF having resistance to the etching solution. The second surface protective film PMF may fill the second through hole RFh of the second dry film resist RF, or may only cover the second through hole RFh. By covering the second dry film resist RF with the second surface protective film PMF, the second surface 10MF of the metal light shielding plate substrate 10M is prevented from being etched simultaneously with the first surface 10MR of the metal light shielding plate substrate 10M.

[0039] When the first recess 10H1 is formed by etching the first surface 10MR, the first recess 10H1 has a depth greater than the distance from the first surface 10R to the central opening HC (see FIG. 3) in the metal light shading plate 10.

[0040] As shown in FIG. 8, after the first recess 10H1 is formed, a second recess 10H2 is formed in the metal light shielding plate substrate 10M, recessed along the thickness direction of the metal light shielding plate substrate 10M through the second dry film resist RF arranged on the second surface 10MF, and having a second opening H2F on the second surface 10MF. The second recess 10H2 has a shape that tapers from the second surface 10MF toward the first surface 10MR. As a result, the second recess 10H2 is connected to the first recess 10H1, and a central opening HC is formed. The second recess 10H2 is the second recess 10H2 that the metal light shielding plate 10 has. Also, the central opening HC is the central opening HC that the metal light shielding plate 10 has.

[0041] When forming the second recess 10H2, the metal light shielding plate substrate 10M is etched using an etching solution capable of etching the metal light shielding plate substrate 10M, in the same manner as when forming the first recess 10H1. Before etching the metal light shielding plate substrate 10M, the first dry film resist RR is removed from the first surface 10MR of the metal light shielding plate substrate 10M. Then, before etching the metal light shielding plate substrate 10M, the first surface 10MR of the metal light shielding plate substrate 10M is covered with a first surface protective film PMR having resistance to the etching solution, and the first recess 10H1 is filled. By covering the first surface 10MR of the metal light shielding plate substrate 10M with the first surface protective film PMR, the first surface 10MR side of the metal light shielding plate substrate 10M is prevented from being etched simultaneously with the second surface 10MF of the metal light shielding plate substrate 10M.

[0042] In the etching of the second recess 10H2, the second surface 10MF of the metal light shielding plate substrate 10M is etched in a state in which the first recess 10H1 is filled with the first surface protective film PMR. Therefore, after the etching of the second surface 10MF reaches the first surface protective film PMR, the supply of the etching liquid to the metal light shielding plate substrate 10M is controlled by the first surface protective film PMR. This makes it possible to improve the accuracy of the cross-sectional shape of the second recess 10H2 even when the thickness of the metal light shielding plate substrate 10M is in a wide range of 10 μm or more and 50 μm or less. On the other hand, if the first recess 10H1 is not filled with the first surface protective film PMR, when the metal light shielding plate substrate 10M is penetrated by the connection between the first recess 10H1 and the second recess 10H2, the etching liquid leaks toward the first surface 10MR of the metal light shielding plate substrate 10M through the connection between the first recess 10H1 and the second recess 10H2. As a result, the accuracy of the shape of the first recess 10H1 and the shape of the second recess 10H2 decreases.

[0043] After the first recess 10H1 and the second recess 10H2 are formed in the metal light shielding plate substrate 10M, the second dry film resist RF is removed from the second surface 10MF, and the first surface protective film PMR is removed from the first surface 10MR. In this manner, the metal light shielding plate 10 shown in Figs. 2 and 3 can be obtained.

[0044] In the manufacturing method of the metal light shading plate 10 described above, for example, after the second dry film resist RF and the first surface protective film PMR are removed from the metal light shading plate substrate 10M, an anti-reflection film may be formed to cover the second surface 10MF, the first surface 10MR, and the side surfaces of the first recess 10H1 and the second recess 10H2. As described above, the anti-reflection film has a lower reflectance than the metal light shading plate substrate 10M, and has the function of absorbing a portion of the light incident on the anti-reflection film. The anti-reflection film is, for example, a black coating. The anti-reflection film may be formed on the metal light-shielding plate substrate 10M using a film-forming method such as a sputtering method or a vapor deposition method. Alternatively, the anti-reflection film may be formed on the metal light-shielding plate substrate 10M by bringing the metal light-shielding plate substrate 10M into contact with a liquid for forming the anti-reflection film.

[0045] In the manufacturing method of the metal light shielding plate 10 described above, the first dry film resist RR does not have to be removed before forming the first surface protective film PMR. In this case, it is sufficient to form the first surface protective film PMR that covers the first dry film resist RR and fills the first recess 10H1. In addition, the first surface protective film PMR may be removed from the first surface 10MR together with the first dry film resist RR after the second recess 10H2 is formed by etching the second surface 10MF.

[0046] [Camera module] Next, the camera module will be described with reference to Fig. 9. Fig. 9 shows a schematic configuration of the camera module.

[0047] As shown in FIG. 9, the camera module 20 includes the above-mentioned metal light shading plate 10, lens 21, and imaging element 22. The lens 21 transmits light that has passed through the hole in the metal light shading plate 10. The light that has passed through the lens 21 is incident on the imaging element 22. The metal light shading plate 10 is positioned on the light incident side of the lens 21 with the first surface 10R facing the lens 21. Compared to the case where the second surface 10F of the metal light shading plate 10 faces the lens 21, it is possible to limit the light that enters the lens 21 by being reflected by the side surface of the hole 10H after passing through the central opening HC.

[0048] The diameter of the central opening HC of the metal light shielding plate 10 may be equal to or smaller than the effective diameter of the lens 21. This prevents light that has passed through the central opening HC from entering outside the effective diameter of the lens 21. This prevents unintended light from entering the imaging element 22.

[0049] The imaging element 22 may be a CCD image sensor or a CMOS image sensor. In the camera module 20, one metal light shielding plate 10 and one lens 21 adjacent to the metal light shielding plate 10 on the optical axis of light that has passed through the metal light shielding plate 10 form one lens unit. The camera module 20 may also include a plurality of lens units. The camera module is not limited to including the lens 21, the imaging element 22, and the like described above, but may include at least one metal light-shielding plate 10.

[0050] The camera module 20 is mounted on various electronic devices. The electronic devices include the above-mentioned camera module 20 and a housing that supports the camera module 20. The electronic devices may be, for example, a smartphone, a tablet personal computer, or a notebook personal computer.

[0051] In the metal light shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the first surface 10MR (surface) is 0.142 μm or more in a 50-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more in a 50-fold field of view. Therefore, the adhesion at the interface between the first surface 10MR of the metal light shielding plate substrate 10M and the first dry film resist RR can be improved. This makes it possible to suppress the occurrence of wobbling on the edge of the first opening H1R of the first recess 10H1 or on the side surface (inner surface) of the first recess 10H1 when the first dry film resist RR is used to form the first recess 10H1 in the metal light shielding plate substrate 10M. Therefore, in the manufactured metal light shielding plate 10, it is possible to suppress the occurrence of wobbling on the edge of the hole 10H or the occurrence of variation in the dimensions of the hole 10H. As a result, the light shielding performance of the metal light shielding plate 10 can be secured.

[0052] In addition, in the metal light shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more in a 150-fold visual field, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more in a 150-fold visual field. Therefore, it is possible to reliably improve the adhesion at the interface between the first surface 10MR of the metal light shielding plate substrate 10M and the first dry film resist RR. This makes it possible to more reliably suppress the occurrence of wobbling on the edge of the first opening H1R of the first recess 10H1 or the side surface (inner surface) of the first recess 10H1 when forming the first recess 10H1 in the metal light shielding plate substrate 10M.

[0053] In addition, in the metal light shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the second surface 10MF, which is the surface opposite to the first surface 10MR, is 0.142 μm or more in a 50-fold visual field, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more in a 50-fold visual field. Therefore, in addition to the first surface 10MR, the adhesion between the metal light shielding plate substrate 10M and the second dry film resist RF can also be increased on the second surface 10MF. This makes it possible to suppress the occurrence of wobbling on the edge of the second opening H2F of the second recess 10H2 or on the side surface (inner surface) of the second recess 10H2 when forming the second recess 10H2 in the metal light shielding plate substrate 10M using the second dry film resist RF. Therefore, in the manufactured metal light shielding plate 10, it is possible to more effectively suppress the occurrence of wobbling on the edge of the hole 10H and the occurrence of variation in the dimensions of the hole 10H. As a result, the light shielding performance of the metal light shielding plate 10 can be secured.

[0054] In addition, in the metal light shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more in a 150-fold visual field, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more in a 150-fold visual field. Therefore, the adhesion between the metal light shielding plate substrate 10M and the second dry film resist RF on the second surface 10MF can be reliably improved. This makes it possible to more reliably suppress the occurrence of wobbling on the edge of the second opening H2F of the second recess 10H2 or on the side surface (inner surface) of the second recess 10H2 when forming the second recess 10H2 in the metal light shielding plate substrate 10M.

[0055] In addition, the metal light shielding plate base material 10M of this embodiment is made of an alloy mainly composed of iron and chromium. Therefore, the adhesion between the metal light shielding plate base material 10M and the first dry film resist RR and the second dry film resist RF can be effectively improved, and as a result, the occurrence of wobbling on the edges of the first and second openings H1R and H2F of the first and second recesses 10H1 and 10H2 formed in the metal light shielding plate 10 and on the side surfaces (inner surfaces) of the first and second recesses 10H1 and 10H2 can be effectively suppressed.

[0056] The metal light shading plate substrate according to the present invention will be further described using experimental examples (Examples 1 to 6 and Comparative Examples 1 to 3). The technical scope of the present invention is not limited in any way by the specific contents of the experimental examples.

[0057] [Measurement of surface roughness] The metal light shading plate substrates of Examples 1 to 6 and Comparative Examples 1 to 3 were all stainless steel foils having a thickness of 25 μm. The three-dimensional surface roughness Sa and three-dimensional surface roughness Sz of the first and second surfaces of the metal light shading plate substrates of Examples 1 to 6 and Comparative Examples 1 to 3 were measured by the following method.

[0058] The three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz were measured using a shape analysis laser microscope (VK-X210, manufactured by Keyence Corporation) equipped with 50x and 150x objective lenses. In the case of the 50x lens, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz were measured on a surface having a width of about 280 μm in one direction and a width of about 220 μm in a direction perpendicular to the one direction. In the case of the 150x lens, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz were measured on a surface having a width of about 90 μm in one direction and a width of about 70 μm in a direction perpendicular to the one direction. The three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz were measured in a direction conforming to ISO 25178.

[0059] For each of the metal light-shielding plate substrates of Examples 1 to 6 and Comparative Examples 1 to 3, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz in the case of a 50x lens, and the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz in the case of a 150x lens were measured, and the results are shown in Table 1. Table 1 shows only the measurement results of the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of the first surface, but the measurement results of the second surface are the same as those of the first surface.

[0060] [Table 1]

[0061] As shown in Table 1, the metal light shading plate substrate of Example 1 has a three-dimensional surface roughness Sa of 0.151 μm at a 50x magnification (×50) and a three-dimensional surface roughness Sz of 2.910 μm at a 50x magnification. Also, the metal light shading plate substrate of Example 1 has a three-dimensional surface roughness Sa of 0.116 μm at a 150x magnification (×150) and a three-dimensional surface roughness Sz of 1.338 μm at a 150x magnification.

[0062] In the metal light shading plate substrate of Example 2, the three-dimensional surface roughness Sa is 0.165 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 2.982 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Example 2, the three-dimensional surface roughness Sa is 0.111 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 1.494 μm at a magnification of 150.

[0063] In the metal light shading plate substrate of Example 3, the three-dimensional surface roughness Sa is 0.159 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 2.896 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Example 3, the three-dimensional surface roughness Sa is 0.110 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 1.429 μm at a magnification of 150.

[0064] In the metal light shading plate substrate of Example 4, the three-dimensional surface roughness Sa is 0.153 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 2.823 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Example 4, the three-dimensional surface roughness Sa is 0.109 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 1.304 μm at a magnification of 150.

[0065] In the metal light shading plate substrate of Example 5, the three-dimensional surface roughness Sa is 0.145 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 2.750 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Example 5, the three-dimensional surface roughness Sa is 0.113 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 1.320 μm at a magnification of 150.

[0066] In the metal light shielding plate substrate of Example 6, the three-dimensional surface roughness Sa is 0.142 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 2.666 μm at a magnification of 50. In addition, in the metal light shielding plate substrate of Example 6, the three-dimensional surface roughness Sa is 0.111 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 1.289 μm at a magnification of 150.

[0067] In the metal light shading plate substrate of Comparative Example 1, the three-dimensional surface roughness Sa is 0.099 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 1.808 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Comparative Example 1, the three-dimensional surface roughness Sa is 0.078 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 0.886 μm at a magnification of 150.

[0068] In the metal light shading plate substrate of Comparative Example 2, the three-dimensional surface roughness Sa is 0.096 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 1.691 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Comparative Example 2, the three-dimensional surface roughness Sa is 0.071 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 0.803 μm at a magnification of 150.

[0069] In the metal light shading plate substrate of Comparative Example 3, the three-dimensional surface roughness Sa is 0.093 μm at a magnification of 50, and the three-dimensional surface roughness Sz is 1.631 μm at a magnification of 50. In addition, in the metal light shading plate substrate of Comparative Example 3, the three-dimensional surface roughness Sa is 0.061 μm at a magnification of 150, and the three-dimensional surface roughness Sz is 0.727 μm at a magnification of 150.

[0070] Using the metal light shading plate substrates of Examples 1 to 6 and Comparative Examples 1 to 3 described above, the metal light shading plates of Examples 1 to 6 and Comparative Examples 1 to 3 were manufactured in the same procedure as the manufacturing method shown in Figures 5 to 8. That is, a first recess was formed by etching the metal light shading plate substrate from the first surface of the metal light shading plate substrate, and then a second recess was formed by etching the metal light shading plate substrate from the second surface of the metal light shading plate substrate. This resulted in a metal light shading plate having a hole formed by the first recess and the second recess. The target value of the first diameter of the first recess was 491 μm, and the target value of the second diameter of the second recess was 571 μm. A large number of holes were formed in each of the metal light shading plates of Examples 1 to 6 and Comparative Examples 1 to 3.

[0071] For each of the metal light shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 manufactured as described above, the edge of the hole 10H was visually observed in the field of view of a laser microscope illustrated in Fig. 10 and Fig. 11, and the wobble of the edge of the hole 10H was evaluated. Those having no wobble on the edge of the hole 10H as illustrated in Fig. 10 were rated as "○" (good), and those having wobble on the edge of the hole 10H as illustrated in Fig. 11 were rated as "×" (unacceptable). The evaluation results of the wobble on the edge of the hole 10H are shown in Table 2.

[0072] [Table 2]

[0073] As shown in Table 2, the metal light shading plates of Comparative Examples 1 to 3 all had a rattle at the edge of the hole 10H. This is believed to be due to the fact that the three-dimensional surface roughness Sa of the metal light shading plate base material used in the manufacture of the metal light shading plates of Comparative Examples 1 to 3 is smaller than 0.142 μm at a 50x magnification and the three-dimensional surface roughness Sz is smaller than 2.666 μm at a 50x magnification. Also, the metal light shading plates of Comparative Examples 1 to 3 all had a three-dimensional surface roughness Sa of smaller than 0.109 μm at a 150x magnification and the three-dimensional surface roughness Sz is smaller than 1.289 μm at a 150x magnification. On the other hand, in the metal light shielding plates of Examples 1 to 6, there was no wobbling at the edge of the hole 10H. This is believed to be due to the fact that in the metal light shielding plates of Examples 1 to 6, the three-dimensional surface roughness Sa was 0.142 μm or more at a 50x magnification and the three-dimensional surface roughness Sz was 2.666 μm or more at a 50x magnification. Also, in the metal light shielding plates of Examples 1 to 6, the three-dimensional surface roughness Sa was 0.109 μm or more at a 150x magnification and the three-dimensional surface roughness Sz was 1.289 μm or more at a 150x magnification.

[0074] In addition, the first diameter DH1 (see FIG. 3) of the first recess of the many holes formed in each of the manufactured metal light shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 was measured. The number of holes (n [pieces]) whose first diameter was measured was 3200 for each of the metal light shielding plates of Examples 1 to 6, and 648 for Comparative Examples 1 to 3. For each of the metal light shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3, the average value of the first diameter (ave [μm]), the maximum value of the first diameter (max [μm]), the minimum value of the first diameter (min [μm]), the difference between the maximum value and the minimum value of the first diameter (max-min [μm]), and the standard deviation (σ [μm]) were obtained. The results are shown in Table 3.

[0075] [Table 3]

[0076] As shown in Table 3, the first diameter difference (max-min [μm]) is relatively large, at 10 μm or more, in the metal light shading plates of Comparative Examples 1 to 3. This is thought to be due to the fact that the edges of the holes in the metal light shading plates of Comparative Examples 1 to 3 are uneven. On the other hand, in the metal light shading plates of Examples 1 to 6, the difference in the first diameter (max-min [μm]) is relatively small, being 7 μm or less. This is thought to be due to the fact that the metal light shading plates of Examples 1 to 6 have no wobble at the edge of the hole.

[0077] In addition, the dimensional variation of the first diameter was evaluated based on the standard deviation σ (see Table 3) of the first diameter in each of the metal light shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3. Standard deviation σ of 1.0 μm or less was evaluated as "◎" (excellent; very small dimensional variation), standard deviation σ of 2.0 μm or less was evaluated as "○" (good; small dimensional variation), and standard deviation σ of more than 2.0 μm was evaluated as "×" (poor; large dimensional variation). The evaluation results of the dimensional variation of the first diameter are shown in Table 4.

[0078] [Table 4]

[0079] As shown in Table 4, the dimensional variation of the first diameter of the holes in the metal light shading plates of Comparative Examples 1 to 3 was evaluated as "x". This is considered to be due to the fact that the edges of the holes in the metal light shading plates of Comparative Examples 1 to 3 are uneven. On the other hand, in the metal light shading plates of Examples 1 to 4, the dimensional variation of the first diameter of the holes was evaluated as "◎". Also, in the metal light shading plates of Examples 5 to 6, the dimensional variation of the first diameter of the holes was evaluated as "○". This is thought to be due to the fact that there is no wobble on the edges of the holes in the metal light shading plates of Examples 1 to 6. [Explanation of symbols]

[0080] 10 Metal shade plate 10F 2nd side 10R First side (front) 10H hole 10H1 First recess (recess) 10M metal light shielding plate base material 10MF second side 10MR first side (front) 20 Camera Module 21 Lens 22 Image sensor H1R First opening (opening) RF 2nd Dry Film Resist RR First Dry Film Resist RRh First through hole (through hole)

Claims

1. A substrate used in a metal light shielding plate, The three-dimensional surface roughness Sa of the surface is 0.142 μm or more in a 50x field of view, A metal light-shielding plate substrate, the three-dimensional surface roughness Sz of the surface being 2.666 μm or more at a 50x magnification.

2. The three-dimensional surface roughness Sa of the surface is 0.109 μm or more in a 150-times magnification field; The metal light-shielding plate substrate according to claim 1 , wherein the three-dimensional surface roughness Sz of the surface is 1.289 μm or more when viewed at 150 times magnification.

3. the surface is a first surface, Further comprising a second surface opposite to the first surface, The three-dimensional surface roughness Sa of the second surface is 0.142 μm or more in a 50x field of view; The metal light-shielding plate substrate according to claim 1 or claim 2, wherein the three-dimensional surface roughness Sz of the second surface is 2.666 μm or more in a 50x field of view.

4. The three-dimensional surface roughness Sa of the second surface is 0.109 μm or more in a 150-times magnification field; The metal light-shielding plate substrate according to claim 3, wherein the three-dimensional surface roughness Sz of the second surface is 1.289 μm or more when viewed at 150 times magnification.

5. The metal light-shielding plate substrate according to claim 1 or 2, wherein the metal light-shielding plate substrate is made of an alloy containing iron and chromium as main components.

6. A metal light-shielding plate using the metal light-shielding plate substrate according to claim 1 or 2.

7. A camera module using the metal light shielding plate according to claim 6.

8. An electronic device using the camera module according to claim 7.

9. A method for manufacturing a metal light shielding plate, comprising the steps of: A metal light-shielding plate substrate is prepared, the metal light-shielding plate substrate being configured to have a dry film resist attached thereto, the metal light-shielding plate substrate having a surface on which an opening is formed by etching the surface using the patterned dry film resist, the three-dimensional surface roughness Sa of the surface being 0.142 μm or more at a 50x magnification, and the three-dimensional surface roughness Sz of the surface being 2.666 μm or more at a 50x magnification; disposing the dry film resist on the surface; forming a through hole in the dry film resist for forming a recess in the metal light shielding plate base material, the recess being recessed along a thickness direction of the metal light shielding plate base material and having the opening on the surface; forming the recess in the metal light shielding plate substrate via the dry film resist; and removing the dry film resist from the metal light-shielding plate substrate in which the recess is formed.

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