CN116381825A

CN116381825A - Composite structural member, processing method thereof and electronic equipment

Info

Publication number: CN116381825A
Application number: CN202310206709.6A
Authority: CN
Inventors: 缪灯奎; 许文彬; 乔艳党; 张洪
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-07-04
Anticipated expiration: 2043-02-24
Also published as: CN116381825B

Abstract

The application discloses a composite structural member, a processing method thereof and electronic equipment, relates to the technical field of composite structural members, and can ensure the wear resistance of the composite structural member and reduce the cost of the composite structural member while the appearance of the composite structural member has true gold texture. Wherein the composite structural member comprises: a substrate and an optical modifying film layer, the substrate comprising a first surface; the optical adjusting film layer is arranged on one side of the first surface facing to the first surface, and the Vickers hardness of the optical adjusting film layer is more than or equal to 800; the composite structural member comprises a first appearance surface, wherein the optical adjusting film layer is used for adjusting the color of the first appearance surface so that the first appearance surface is in a preset color, L values, a values and b values corresponding to the preset color in a Lab color space are respectively L0, a0 and b0, L0 is more than or equal to 85 and less than or equal to 92, a0 is more than or equal to 2 and less than or equal to 5, and b0 is more than or equal to 22 and less than or equal to 30.

Description

Composite structural member, processing method thereof and electronic equipment

Technical Field

The application relates to the technical field of composite structural members, in particular to a composite structural member, a processing method thereof and electronic equipment.

Background

Gold is commonly referred to as elemental (free form) gold. Gold is a noble metal and has been used for many centuries as money, a value-keeping article, and ornaments such as rings, necklaces, earrings, bracelets, etc., so that gold-colored articles are generally regarded as advanced articles. However, since gold is produced in nature in a small amount, and is expensive, if structural members such as a case and a decoration of electronic devices such as a wristwatch, a cellular phone, a tablet computer, a notebook computer, etc. are directly made of gold, the cost is too high and the wear resistance of the structural members cannot be ensured.

Disclosure of Invention

The embodiment of the application provides a composite structural member, a processing method thereof and electronic equipment, which can ensure the wear resistance of the composite structural member and reduce the cost of the composite structural member while the appearance of the composite structural member has true gold texture.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

in a first aspect, embodiments of the present application provide a composite structural member comprising: a substrate and an optical modifying film layer, the substrate comprising a first surface; the optical adjustment film layer is arranged on one side, facing the first surface, of the optical adjustment film layer, and comprises at least one high-refractive-index film layer and at least one low-refractive-index film layer which are sequentially laminated and alternately arranged, wherein the refractive index of the high-refractive-index film layer is larger than that of the low-refractive-index film layer, and the Vickers hardness of the optical adjustment film layer is larger than or equal to 800; the composite structural member comprises a first appearance surface, the orientation of the first appearance surface is the same as that of the first surface, the optical adjusting film layer is used for adjusting the color of the first appearance surface so that the first appearance surface is in a preset color, the corresponding L value, a value and b value of the preset color in a Lab color space are respectively L0, a0 and b0, L0 is more than or equal to 85 and less than or equal to 92, a0 is more than or equal to 2 and less than or equal to 5, and b0 is more than or equal to 22 and less than or equal to 30.

According to the composite structural material piece, the appearance color of the composite structural material piece is adjusted through the optical adjustment film layer, so that the appearance of the composite structural material piece reaches the appearance color effect of true gold, and the cost of the composite structural material piece can be reduced while the true gold texture of the composite structural material piece is ensured. Meanwhile, in the composite structural member in the embodiment of the application, the Vickers hardness of the optical adjustment film layer is set to be more than or equal to 800, so that the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member can be improved, and the service life of the composite structural member can be prolonged.

In one possible implementation manner of the first aspect, the vickers hardness of the optical adjustment film layer is 800, 850, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200, 2500, or 3000.

In one possible implementation manner of the first aspect, the refractive index of the high refractive index film layer is greater than or equal to 1.75, and the refractive index of the low refractive index film layer is less than 1.75. Therefore, the color of the first appearance surface is conveniently adjusted to a preset color through the optical adjusting film layer, materials of the high-refractive-index film layer and the low-refractive-index film layer are easy to obtain, and the processing difficulty of the composite structural member can be reduced.

In one possible implementation manner of the first aspect, the refractive index of the high refractive index film layer is greater than or equal to 1.85 and less than or equal to 2.4; the low refractive index film layer has a refractive index of 1.4 or more and 1.65 or less. In this way, the refractive index difference between the high refractive index film layer and the low refractive index film layer is larger, the more obvious the refractive effect of the interface between the adjacent low refractive index film layer and the low refractive index film layer is, the reflection capability of the optical adjusting film layer on specific wavelength can be enhanced, the first appearance surface of the composite material structural member can be conveniently adjusted to a preset color, and the appearance of the composite material structural member presents true gold texture.

In one possible implementation manner of the first aspect, the material of the high refractive index film layer includes at least one of silicon nitride, aluminum nitride, titanium oxide, tantalum oxide, and niobium oxide; and/or the material of the low refractive index film layer comprises at least one of silicon oxide and aluminum oxide. The materials have better optical performance, can meet the refractive index requirement, have larger Vickers hardness and can meet the hardness requirement of the optical adjustment film layer. In addition, precursors for these materials are readily available and can be processed by atomic layer deposition processes.

In one possible implementation of the first aspect, the thickness of the optical adjustment film layer is greater than or equal to 1 micron and less than or equal to 3 microns. Specifically, the thickness of the optical modifying film layer 32 may be 1 micron, 1.5 microns, 2 microns, 2.5 microns, 3 microns, etc. The thickness of the optical adjustment film layer is smaller, which is beneficial to reducing the overall thickness of the composite structural member.

In one possible implementation manner of the first aspect, the number of layers of the optical adjustment film is greater than or equal to 3 and less than or equal to 5. Specifically, the number of the optical adjustment film layers is 3, 4 or 5. Therefore, the structure of the optical adjustment film layer can be simplified, and the design difficulty of the optical adjustment film layer is reduced.

In one possible implementation manner of the first aspect, the composite structural member further includes a color layer, the color layer is disposed between the first surface and the optical adjustment film layer, the color of the color layer is a first color, the corresponding L value, a value, b value of the first color in the Lab color space are L1, a1, and b1, respectively, Δl is less than or equal to 20, Δa is less than or equal to 5, and Δb is less than or equal to 15; wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|. Therefore, the color difference between the first color and the preset color can be reduced, and the design difficulty of the optical adjustment film layer can be reduced, so that the thickness of the optical adjustment film layer can be reduced while the first appearance surface is adjusted to the preset color, and the overall thickness of the composite structural member can be reduced.

In one possible implementation of the first aspect, Δl is less than or equal to 15, Δa is less than or equal to 5, and Δb is less than or equal to 10. In this way, the color difference between the first color and the preset color can be further reduced.

In a possible implementation manner of the first aspect, the material of the color layer includes at least one of zirconium nitride, titanium nitride, tantalum carbide, aluminum titanium nitride, and hafnium nitride. The color layer processed by the materials is approximately golden, namely the first color is approximately golden, can meet the conditions that DeltaL is less than or equal to 20, deltaa is less than or equal to 5 and Deltab is less than or equal to 15, can reduce the thickness of the optical adjustment film layer while adjusting the first appearance surface to a preset color,

in one possible implementation manner of the first aspect, the vickers hardness of the color layer is greater than or equal to 800. Therefore, the hardness of the color layer is high, and the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member can be further improved.

In one possible implementation of the first aspect, the thickness of the color layer is greater than or equal to 80 nanometers and less than or equal to 3000 nanometers. Therefore, the color difference between the first color and the preset color can be reduced while the wear resistance, corrosion resistance, drop resistance and scratch resistance of the composite structural member are ensured, and meanwhile, the material consumption of the color layer can be reduced, and the molding difficulty and the material consumption cost of the color layer are reduced.

In a possible implementation manner of the first aspect, the material of the color layer is titanium nitride, the low refractive index film layer includes a first low refractive index film layer and a second low refractive index film layer, the high refractive index film layer includes a first high refractive index film layer, a second high refractive index film layer and a third high refractive index film layer, and in a direction from the substrate to the optical adjustment film layer, the first high refractive index film layer, the first low refractive index film layer, the second high refractive index film layer, the second low refractive index film layer and the third high refractive index film layer are sequentially stacked; the first low-refractive-index film layer and the second low-refractive-index film layer are made of aluminum oxide, the thickness of the first low-refractive-index film layer is larger than or equal to 70 nanometers and smaller than or equal to 75 nanometers, and the thickness of the second low-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers; the first high-refractive-index film layer, the second high-refractive-index film layer and the third high-refractive-index film layer are all made of titanium oxide, the thickness of the first high-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers, the thickness of the second high-refractive-index film layer is larger than or equal to 75 nanometers and smaller than or equal to 80 nanometers, and the thickness of the third high-refractive-index film layer is larger than or equal to 65 nanometers and smaller than or equal to 70 nanometers. A specific structure of an optical tuning film is provided.

Therefore, the structure of the optical adjustment film layer can be simplified while the first appearance surface of the composite material presents the true gold texture, the thickness of the optical adjustment film layer is reduced, the processing difficulty of the optical adjustment film layer is reduced, and the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite material structure can be improved.

In a possible implementation manner of the first aspect, the material of the color layer is titanium nitride, the low refractive index film layer includes a first low refractive index film layer and a second low refractive index film layer, the high refractive index film layer includes a first high refractive index film layer, a second high refractive index film layer and a third high refractive index film layer, and in a direction from the substrate to the optical adjustment film layer, the first high refractive index film layer, the first low refractive index film layer, the second high refractive index film layer, the second low refractive index film layer and the third high refractive index film layer are sequentially stacked; the first low-refractive-index film layer and the second low-refractive-index film layer are made of aluminum oxide, and the first high-refractive-index film layer, the second high-refractive-index film layer and the third high-refractive-index film layer are made of titanium oxide. A specific structure of an optical tuning film is provided.

In a possible implementation manner of the first aspect, the material of the color layer is zirconium nitride, the low refractive index film layer includes a first low refractive index film layer, the high refractive index film layer includes a first high refractive index film layer and a second high refractive index film layer, and the first high refractive index film layer, the first low refractive index film layer, and the second high refractive index film layer are sequentially stacked in a direction from the substrate to the optical adjustment film layer; the first low refractive index film layer is made of alumina, and the thickness of the first low refractive index film layer is more than or equal to 100 nanometers and less than or equal to 120 nanometers; the first high-refractive-index film layer and the second high-refractive-index film layer are both made of chromium oxide, the thickness of the first high-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers, and the thickness of the second high-refractive-index film layer is larger than or equal to 75 nanometers and smaller than or equal to 80 nanometers. Another specific structure of the optical modifying film is provided.

In a possible implementation manner of the first aspect, the material of the color layer is zirconium nitride, the low refractive index film layer includes a first low refractive index film layer, the high refractive index film layer includes a first high refractive index film layer and a second high refractive index film layer, and the first high refractive index film layer, the first low refractive index film layer, and the second high refractive index film layer are sequentially stacked in a direction from the substrate to the optical adjustment film layer; the first low-refractive-index film layer is made of aluminum oxide, and the first high-refractive-index film layer and the second high-refractive-index film layer are made of chromium oxide. Another specific structure of the optical modifying film is provided.

In one possible implementation manner of the first aspect, the composite structural member further includes: a priming layer disposed between the color layer and the first surface of the substrate; the material of the priming layer comprises at least one of aluminum, chromium, titanium, silicon and silicon oxide. The priming layer is used for increasing the adhesive force between the base material and the color layer, and can effectively prevent the color layer from falling off from the first surface of the base material, thereby further improving the wear resistance of the composite structural member. Meanwhile, the priming layer can provide a cut-off interface for stripping of defective film layers, and the stripping liquid is prevented from damaging the base material.

In one possible implementation of the first aspect, the thickness of the primer layer is greater than or equal to 50 nanometers and less than or equal to 500 nanometers. Therefore, the thickness of the priming layer is moderate, the adhesive force between the color layer and the base material can be increased, and the whole thickness of the composite structural member is reduced.

In one possible implementation manner of the first aspect, the composite structural member further includes: the fingerprint-preventing layer is arranged on the surface of one side of the optical adjustment film layer, which is away from the base material. Therefore, the appearance surface of the composite structural member has the fingerprint prevention performance, and the aim of reducing fingerprint residues can be fulfilled.

In one possible implementation manner of the first aspect, the thickness of the anti-fingerprint layer is greater than or equal to 10nm and less than or equal to 30 nm. Illustratively, the anti-fingerprint layer may have a thickness of 10nm, 12nm, 15nm, 16nm, 18nm, 20nm, 22nm, 25nm, 28nm, 29nm, 30nm, etc. Therefore, the protection effect of the fingerprint-preventing layer can be ensured, and the overall thickness of the composite structural material piece is considered.

In a possible implementation manner of the first aspect, a transition layer is provided between the optical adjustment film layer and the anti-fingerprint layer. In this way, the adhesion between the anti-fingerprint layer and the optical adjustment film layer can be improved.

In one possible implementation manner of the first aspect, the thickness of the transition layer is greater than or equal to 8nm and less than or equal to 15 nm. Therefore, the adhesive force between the anti-fingerprint layer and the optical adjustment film layer can be improved, and the overall thickness of the composite structural material piece can be considered.

In one possible implementation of the first aspect, the material of the substrate is a metal. Thus, the material of the base material is easy to obtain and the molding is simple, and the cost and the molding difficulty of the base material can be reduced. In addition, the structural strength of the metal is higher, the wall thickness and the material consumption of the base material can be reduced on the premise of ensuring that the structural strength of the base material is unchanged, the internal space of the electronic equipment is increased, the layout of the electronic equipment is optimized, and the light and thin and miniaturized design of the electronic equipment is realized.

In a possible implementation manner of the first aspect, the material is glass, ceramic or plastic. In this way, the material of the substrate is easily available and at low cost.

In a possible implementation manner of the first aspect, the color layer is formed on a side of the first surface of the substrate facing by using a magnetron sputtering process. Thus, the prepared color layer has higher hardness and better corrosion resistance, drop resistance and scratch resistance.

In one possible implementation manner of the first aspect, the visible light absorption rate of the optical adjustment film layer is less than or equal to 3%. Specifically, the visible light absorptivity of the optical adjustment film layer may be 3%, 2%, 1%, 0.8%, 0.6%, 0.4%, 0.2%, or 0.1%. Therefore, the optical adjusting film layer absorbs less light, and the brightness of the first appearance surface of the composite material structural member is improved.

In a possible implementation manner of the first aspect, the film layer of the optical adjustment film layer far from the substrate and the film layer of the optical adjustment film layer close to the substrate are both high refractive index film layers. Therefore, the thickness of the optical adjustment film layer can be further reduced, the reflectivity of visible light is larger, and the light-increasing effect can be further improved.

In a second aspect, the present application provides a method of processing a composite structural member, comprising: providing a substrate comprising a first surface; and forming an optical adjustment film layer on one side of the first surface of the substrate facing the first surface, and enabling the first appearance surface of the composite material structural member to be in a preset color, wherein L values, a values and b values corresponding to the preset color in a Lab color space are respectively L0, a0 and b0, L0 is more than or equal to 85 and less than or equal to 90, a0 is more than or equal to 2 and less than or equal to 5, b0 is more than or equal to 22 and less than or equal to 30, and the Vickers hardness of the optical adjustment layer is more than or equal to 800, wherein the orientation of the first appearance surface is the same as that of the first surface.

Therefore, the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member can be improved while the true gold texture of the composite structural member is ensured, and the service life of the composite structural member can be prolonged. Meanwhile, the processing method is simple in process and low in processing cost.

In a possible implementation manner of the second aspect, before forming the optical adjustment film layer on the side facing the first surface of the substrate, the method further includes: forming a color layer on one side of the first surface of the substrate, wherein the color of the color layer is a first color, and the corresponding L value, a value and b value of the first color in the Lab color space are respectively L1, a1 and b1, deltaL is less than or equal to 20, deltaa is less than or equal to 5 and Deltab is less than or equal to 15; wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|.

In one possible implementation manner of the second aspect, forming an optical adjustment film layer on a side of the substrate toward which the first surface faces includes: an optical adjustment film layer is formed on the first surface of the substrate by adopting an atomic layer deposition process. Therefore, the thickness of the optical adjustment film layer is uniform, the optical adjustment film layer is suitable for coating films with complex surfaces, the existence of blank areas which are not deposited on the composite material structural member can be effectively avoided, the appearance consistency of the composite material structural member is good, and the appearance texture of the composite material structural member can be further improved. In addition, the atomic layer deposition process has good environmental protection and is friendly to the environment.

In one possible implementation manner of the second aspect, after forming the optical adjustment film layer on the side facing the first surface of the substrate, the processing method further includes: and forming an anti-fingerprint layer on the surface of the optical adjustment film layer far away from the substrate.

In some embodiments, forming the anti-fingerprint layer on the surface of the optical adjustment film remote from the substrate comprises: and forming an anti-fingerprint layer on the surface of the optical adjustment film layer, which is far away from the substrate, through a vacuum evaporation process. The anti-fingerprint layer formed by adopting the vacuum evaporation process has higher hardness and better scratch resistance.

In a possible implementation manner of the second aspect, before the forming the anti-fingerprint layer on the surface of the optical adjustment film layer away from the substrate, the processing method may further include: and forming a transition layer on the surface of the optical adjustment film layer far away from the substrate. Therefore, the adhesive force between the fingerprint-preventing layer and the optical adjustment film layer can be improved, and the fingerprint-preventing layer can be effectively prevented from falling off from the optical adjustment film layer.

In a third aspect, the present application provides an electronic device comprising a composite structural member according to any one of the above claims, and/or the electronic device comprises a composite structural member produced by a processing method of any one of the above composite structural members, the first appearance surface of the composite structural member forming at least part of the external surface of the electronic device.

In a possible implementation manner of the third aspect, the electronic device includes a display module and a housing, where the display module is disposed in the housing, and the housing includes a composite structural member.

In a possible implementation manner of the third aspect, the electronic device is a wristwatch, and the electronic device further includes a wristband, where the wristband includes a first wristband portion and a second wristband portion, and one end of the first wristband portion and one end of the second wristband portion are respectively connected to opposite ends of the wristwatch body.

In a possible implementation manner of the third aspect, the electronic device is a mobile phone or a tablet computer.

In a fourth aspect, the present application provides a decorative member comprising a composite structural member according to any one of the above claims, and/or a decorative member comprising a composite structural member produced by a method of processing any one of the above composite structural members, a first appearance surface of the composite structural member forming at least part of an outer surface of the decorative member.

In a possible implementation manner of the fourth aspect, the decoration member is at least one of an earring, a ring, a necklace, a bracelet, and a brooch.

The technical effects of any one of the design manners of the second aspect to the fourth aspect may be referred to the technical effects of the different design manners of the first aspect, and will not be described herein.

Drawings

FIG. 1 is a cross-sectional view of a partial structure of a composite structural member according to the related art;

FIG. 2 is a cross-sectional view of a partial structure of another composite structural member provided by the related art;

FIG. 3 is a schematic illustration of a spectral curve of titanium nitride and a spectral curve of gold;

fig. 4 is a schematic structural diagram of an electronic device according to some embodiments of the present application;

FIG. 5 is an exploded view of the watch body of the electronic device of FIG. 4;

FIG. 6 is a cross-sectional view of a composite structural member provided in some embodiments of the present application;

FIG. 7 is a cross-sectional view of a partial structure of the composite structural member of FIG. 6;

FIG. 8 is a schematic diagram of the operation of an optical modifying film layer in the composite structure of FIG. 7;

FIG. 9 is a cross-sectional view of a partial structure of a composite structural member provided in accordance with further embodiments of the present application;

FIG. 10 is a cross-sectional view of a partial structure of a color layer and an optical modifying film layer in a composite structural member provided in some embodiments of the present application;

FIG. 11 is a cross-sectional view of a partial structure of a color layer and an optical modifying film layer in a composite structural member provided in some embodiments herein;

FIG. 12 is a cross-sectional view of a partial structure of a composite structural member provided in accordance with further embodiments of the present application;

FIG. 13 is a cross-sectional view of a partial structure of a composite structural member provided in accordance with further embodiments of the present application;

FIG. 14 is a flow chart of a method of processing a composite structural member provided in some embodiments of the present application;

FIG. 15 is a flow chart of a method of processing a composite structural member according to further embodiments of the present application;

FIG. 16 is a flow chart of a method of processing a composite structural member provided in accordance with further embodiments of the present application;

FIG. 17 is a cross-sectional view of a partial structure of a composite structural member provided in some embodiments of the present application;

FIG. 18 is a flow chart of a method of processing the composite structural member of FIG. 17;

FIG. 19 is a cross-sectional view of a partial structure of a composite structural member provided in accordance with further embodiments of the present application;

fig. 20 is a flow chart of a method of processing the composite structural member shown in fig. 19.

Reference numerals:

100. an electronic device;

1. watchband; 11. a first wristband portion; 111. a first locking part; 12. a second wristband portion; 121. a second locking part;

2. a watch body; 21. a housing; 211. a watch frame; 212. a decorative ring; 213. a back cover; 22. a display module; 221. a light-transmitting cover plate; 222. a display screen; 23. a circuit board assembly;

3. a composite structural member; 3a, a first appearance surface; 301. a gold layer; 302. a metal nitride layer;

31. a substrate; 31a, a first surface;

32. an optical adjustment film layer; 321. a high refractive index film layer; 321a, a first high refractive index film layer; 321b, a second high refractive index film layer; 321c, a third high refractive index film layer; 322. a low refractive index film layer; 322a, a first low refractive index film layer; 322b, a second low refractive index film layer;

33. A color layer; 34. a bottom layer is formed; 341. a first primer layer; 342. a second primer layer; 35. an anti-fingerprint layer; 36. and a transition layer.

Detailed Description

In the embodiments of the present application, the terms "exemplary" or "such as" and the like are used to denote examples, illustrations, or descriptions. Any embodiment or design described herein as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

In the present embodiments, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

In the description of embodiments of the present application, the term "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.

In the description of the embodiment of the present application, "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" in the present application generally indicates that the front-rear association object is an or relationship.

In the description of the embodiments of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and for example, "connected" may be either detachably connected or non-detachably connected; may be directly connected or indirectly connected through an intermediate medium. Wherein, "fixedly connected" means that the relative positional relationship is unchanged after being connected with each other. "rotationally coupled" means coupled to each other and capable of relative rotation after coupling. "slidingly coupled" means coupled to each other and capable of sliding relative to each other after being coupled.

References to directional terms in the embodiments of the present application, such as "inner", "outer", "upper", "lower", "front", "rear", "left", "right", etc., are merely with reference to the directions of the drawings, and thus, the directional terms are used for better, more clear description and understanding of the embodiments of the present application, rather than indicating or implying that the apparatus or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of embodiments of the present application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the description of the embodiments of the present application, the terms "parallel", "perpendicular", "equal" include the stated case and the case that is similar to the stated case, the range of which is within an acceptable deviation range, as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, "parallel" includes absolute parallel and approximately parallel, where the acceptable deviation range for approximately parallel may be, for example, a deviation within 5 °; "vertical" includes absolute vertical and near vertical, where the acceptable deviation range for near vertical may also be deviations within 5 °, for example. "equal" includes absolute equal and approximately equal, where the difference between the two, which may be equal, for example, is less than or equal to 5% of either of them within an acceptable deviation of approximately equal.

For convenience in describing the technical solution of the present application, before describing the composite structural member, the processing method thereof and the electronic device in detail in the embodiments of the present application, some concepts related to the present application will be described first.

Electroplating: a process of plating a thin layer of other metals or alloys on the surface of some metals using the principle of electrolysis. Specifically, in the electroplating process, the plating metal is used as an anode and oxidized into cations to enter the electroplating solution; the metal product to be plated is used as a cathode, and cations of the plating metal are reduced on the surface of the metal to be plated to form a plating layer.

Lab color space (also known as CIELab color space): lab color space is one of the representation methods of color. Lab color space is a color pattern determined by the CIE organization that theoretically includes all the colors that can be seen by the human eye. The Lab color space includes three elements, L value, a value, and b value. L represents brightness, and the range of the L value is 0, 100, and represents from pure black to pure white; the value a represents the range from red to green, and the value range is [127, -128]; the value b represents the range from yellow to blue, and the value range is [127, -128]. All colors are composed of these three values that change interactively. For example, when the Lab color space of a block color is l=100, a=30, and b=0, the block color is pink. The color of gold has L value of 85.00-92.00, a value of 2-5 and b value of 22-30 in Lab color space.

The L value, the a value and the b value of the Lab color space can be measured by a color difference meter. For example, it may be measured by a CM3600 color difference meter.

Color difference: refers to the difference in the two colors.

Physical vapor deposition (physical vapor deposition, PVD): physical vapor deposition refers to a technique of gasifying a material source (solid or liquid) surface into gaseous atoms or molecules or partially ionizing the material source into ions by a physical method under vacuum conditions, and depositing a thin film having a specific function on a substrate surface through a low-pressure gas (or plasma) process. Physical vapor deposition techniques include vacuum evaporation techniques and magnetron sputtering techniques.

Atomic layer deposition (atomic layer deposition, ALD): atomic layer deposition is a method of forming a deposited film by alternately introducing pulses of a vapor precursor into a reactor and chemisorbing and reacting on a deposition substrate.

Gold is commonly referred to as elemental (free form) gold. Gold is a noble metal and has been used for centuries as a money, a value-keeping article, and a decorative member of a ring, a necklace, an earring, a bracelet, etc., so that gold-colored articles are generally regarded as high-grade articles. However, since gold is produced in a small amount in nature, it is expensive, and if structural members such as a case, a decorative member, etc. of electronic devices such as a wristwatch, a cellular phone, a tablet computer, a notebook computer, etc. are directly made of gold, the cost is too high.

In order to achieve the appearance of gold (also referred to as 24K gold) and reduce the cost of the structural member, composite materials are generally used in the related art to manufacture the structural member.

Referring to fig. 1, fig. 1 is a sectional view showing a partial structure of a composite structural member 3 according to the related art. The composite structural member 3 comprises a substrate 31 and a layer of gold 301. The substrate 31 includes a first surface 31a, and the gold layer 301 is disposed on a side facing the first surface 31 a. The first surface 31a may include a part of the surface of the substrate 31, or may include all surfaces of the substrate 31.

The base material 31 is a metal member. Illustratively, the substrate 31 is a stainless steel piece, an aluminum alloy piece, a silver piece, a copper alloy piece, or the like. The gold layer 301 may be formed on the surface of the substrate 31 by an electroplating process.

Thus, by electroplating with gold as the plating metal, a thin gold layer 301 can be plated on the surface of the substrate 31. The gold layer 301 can enable the appearance of the composite structural member 3 to achieve a true gold feel, and has the advantages of strong corrosion resistance, good conductivity, easy welding, high temperature resistance, strong anti-discoloration capability and the like. However, the composite structural part 3 has the following disadvantages: (1) The gold layer 301 is a soft gold film, the annual wear amount is 1-3 micrometers (mu m), when the gold layer 301 wears and falls off to expose the base material 31, the gold layer 301 not only loses the decorative effect, but also forms a local primary cell between the base material 31 and the gold layer 301, so that the corrosion of the base material 31 is accelerated; (2) The thickness of the gold layer 301 is usually required to reach a certain thickness (about 10 micrometers), and the gold consumption is large and the cost is still high; (3) Gold ions in the electroplating solution cannot be fully recovered, and after the electroplating solution is discharged into the environment, the environment is polluted, so that the electroplating solution is not friendly to the environment.

In order to improve the wear resistance of the composite structural member 3 and further reduce the cost, refer to fig. 2, where fig. 2 is a cross-sectional view of a partial structure of another composite structural member 3 according to the related art. The composite structural member 3 comprises a substrate 31 and a metal nitride layer 302. Wherein, the metal nitride refers to a compound formed by a metal element and nitrogen. The metal nitride layer 302 is disposed on the first surface 31a of the substrate 31. The metal nitride layer 302 has the characteristics of higher hardness, good corrosion resistance, wear resistance, oxidation resistance and the like, and can improve the hardness, corrosion resistance, wear resistance and oxidation resistance of the composite structural member. In addition, the metal nitride layer 302 may be formed on the first surface 31a of the substrate 31 by using a magnetron sputtering technology, which has low processing cost, high deposition rate and environmental protection, and can reduce the cost of the composite structural member and avoid environmental pollution.

However, the color of the metal nitride has certain chromatic aberration with that of gold, so that the gold texture of the composite structural member is insufficient.

For example, in some embodiments, the metal nitride layer 302 is a titanium nitride (TiN) layer. Referring to fig. 3, fig. 3 is a schematic diagram of a spectrum curve of titanium nitride and a spectrum curve of gold. In fig. 3, the abscissa indicates wavelength and the ordinate indicates reflectance. It can be seen that the shape of the spectral curve of titanium nitride is very similar to that of gold.

Specifically, the titanium nitride layer has a value of a of 2 to 5 and a value of b of 22 to 26 in the Lab color model, and the ranges of the value of a and the value of b are the same as those of the gold color in the Lab color model. However, the L value of the titanium nitride layer in the Lab color model is 80.00, the L value of the industrially produced titanium nitride layer is only 75.00, and the L value of the gold color in the Lab color model is 85.00-92.00, and the color difference between the two is as high as 10-15 or more, so that the gold texture of the composite structural member 3 is insufficient.

As another example, in other embodiments, the metal nitride layer 302 is a zirconium nitride (ZrN) layer. The corresponding L value of the zirconium nitride layer in the Lab color model is 83.00-87.00 and the corresponding L value of gold in the Lab color model are similar, but the corresponding a value of the zirconium nitride layer in the Lab color model is 1-2, the corresponding b value is 18-20, and the difference between the corresponding a value and the corresponding b value of the color of gold in the Lab color model is larger, so that the gold texture of the composite structural member 3 is insufficient.

In order to ensure the wear resistance of the composite structural member and reduce the cost of the composite structural member while the appearance of the composite structural member has a true gold texture, the composite structural member in the embodiment of the present application is provided with an optical adjustment film layer on the side of the first surface of the substrate, and the appearance color (that is, the color of the first appearance surface mentioned below) of the composite structural member at the first surface is adjusted by the optical adjustment film layer, so that the appearance of the composite structural member achieves the effect of the appearance color of true gold (that is, 24K gold), thereby reducing the cost of the composite structural member while ensuring the true gold texture of the composite structural member. Meanwhile, in the composite structural member in the embodiment of the application, the vickers hardness (code number is HV) of the optical adjustment film layer is set to be more than or equal to 800, so that the corrosion resistance, the wear resistance, the scratch resistance, the drop resistance and the like of the composite structural member can be improved.

Embodiments of the present application will be described in detail below with reference to the accompanying drawings, and prior to describing the embodiments of the present application, application scenarios of the present application will be described first.

The application provides an electronic device, which can be a 3C product, wherein the 3C product is a product combining a computer (computer), a communication (communication) and a consumer electronic product (consumer electronics), and is also called an information household appliance product. In particular, the electronic devices include, but are not limited to, cell phones, tablet computers (tablet personal computer), laptops (lap computers), personal digital assistants (personal digital assistant, PDAs), watches, monitors, cameras, personal computers, notebook computers, in-vehicle devices, augmented reality (augmented reality) glasses, AR helmets, virtual Reality (VR) glasses, VR helmets, or the like.

Referring to fig. 4, fig. 4 is a schematic structural diagram of an electronic device 100 according to some embodiments of the present application. In this embodiment and the following embodiments, the electronic device 100 is exemplified as a wristwatch, which should not be construed as a particular limitation on the structural form of the electronic device 100. Optionally, the watch is a smart watch.

Referring to fig. 4, the electronic device 100 includes a wristband 1 and a wristwatch body 2. The watchband 1 is used for wearing the watch body 2 on the wrist of a human body, and the watch body 2 is used for realizing the main functions of the watch.

In some embodiments, with continued reference to fig. 4, wristband 1 may include a first wristband portion 11 and a second wristband portion 12, with one end of the first wristband portion 11 and one end of the second wristband portion 12 being connected to opposite ends of the watch body 2, respectively. The other end of the first band portion 11 is provided with a first locking portion 111, and the other end of the second band portion 12 is provided with a second locking portion 121. The first locking portion 111 and the second locking portion 121 are detachably locked to each other to wear the wristwatch body 2 on the wrist of a human body. The mating structure formed by the first locking portion 111 and the second locking portion 121 may be a clasp, a hidden clasp, a butterfly clasp, a belt button, a folding safety clasp, a folding clasp, or a needle clasp, which is not limited in this application. It will be appreciated that in other embodiments, the first band portion 11 and the second band portion 12 may be a single piece.

The watch body 2 has a substantially disk shape. In other embodiments, the watch body 2 may also be substantially elliptical, rectangular, square, etc. Referring to fig. 5, fig. 5 is an exploded view of the watch body 2 in the electronic device 100 shown in fig. 4. The watch body 2 includes a display module 22, a case 21, a circuit board assembly 23, and a battery (not shown in fig. 5). It will be appreciated that fig. 5 only schematically shows some of the components comprised by the watch body 2, the actual shape, the actual size, the actual position and the actual configuration of which are not limited by fig. 4.

The display module 22 is used for displaying images, video, data, etc. For example, the display module 22 may be used to display hour, minute, second, dial, digital time, weather, air temperature, ECG, body temperature, heart rate, body fat, voltage, etc. values or graphics. The display module 22 is electrically connected to the circuit board assembly 23, and the circuit board assembly 23 is used for controlling the display module 22 to display the numerical value, the graph or other images.

Referring to fig. 5, the display module 22 includes a transparent cover 221 and a display screen 222 that are stacked. It will be appreciated that fig. 5 only schematically illustrates some of the components included in the display module 22, and the actual shape, actual size, actual position, and actual configuration of these components are not limited by fig. 5.

The light-transmitting cover plate 221 is mainly used for protecting the display screen 222 from water, dust and scratches. The material of the light-transmitting cover plate 221 includes, but is not limited to, glass and sapphire. The display 222 is the core device that displays numerical values and graphics. The display 222 may be a flexible display or a rigid display. Optionally, the display screen 222 is a touch screen.

The housing 21 is used to house and protect the internal electronics of the electronic device 100. Referring to fig. 5, the case 21 may include a bezel 211, a bezel 212, and a back cover 213. The decorative ring 212 and the back cover 213 are respectively disposed at two opposite ends of the bezel 211. The display module 22 is fixed to the bezel 212. The bezel 212 may surround the outer periphery of the display module 22. The interior of the housing 21 forms an accommodation space in which the circuit board assembly 23 and the battery are accommodated.

In the above embodiment, at least part of the housing 21 may be constituted by the composite structural member 3. That is, the housing 21 comprises the composite structural member 3. For example, the bezel 211 in the housing 21 may be one form of structure of the composite structural member 3 provided herein. Of course, the composite structural member 3 is not limited to the bezel 211 in the case 21, and may be at least one of the back cover 213 and the bezel 212.

It will be appreciated that the composite structural member 3 may be of other construction when the electronic device 100 is a product other than a wristwatch. For example, when the electronic device 100 is a mobile phone or tablet computer, the composite structural member 3 may be a middle frame or back cover of the mobile phone or tablet computer. As another example, when the electronic device 100 is a notebook computer, the composite structural member 3 may be a C-shell or a D-shell of the notebook computer. In addition, the composite structural member 3 may be used for a decorative member such as jewelry, apparel, and upholstery, in addition to the electronic device 100, and for example, the composite structural member 3 may be used for a ring, necklace, earring, bracelet, brooch, button, door handle, and the like.

The following description is mainly given by way of example of the application of the composite structural member 3 to the bezel 211 of a wristwatch, which is not to be considered as a particular limitation of the construction of the present application. Referring to fig. 6-7, fig. 6 is a cross-sectional view of a composite structural member 3 according to some embodiments of the present application, and fig. 7 is a cross-sectional view of a partial structure of the composite structural member 3 shown in fig. 6. The composite structure 3 comprises a substrate 31 and an optical modifying film layer 32.

Specifically, the substrate 31 includes a first surface 31a. The composite structural member 3 includes a first exterior surface 3a, and the first surface 31a is oriented in the same direction as the first exterior surface 3a. The optical adjustment film 32 is disposed on a side of the substrate 31 facing the first surface 31a.

It will be appreciated that the first surface 31a may form the first facing 3a of the composite structural member 3 after providing the film layer. After the first surface 31a is provided with a film layer, the first surface 31a of the substrate 31 is not visible to the user. The first appearance surface 3a of the composite structural member 3 is visible to a user. The surface of the composite structural part 3 facing away from the substrate 31 is formed as a first appearance surface 3a. For example, in the example of fig. 7, the surface of the optical adjustment film layer 32 facing away from the base material 31 is formed as the first appearance surface 3a. The first surface 31a may include a part of the surface of the substrate 31, or may include all the surfaces of the substrate 31.

For example, when the composite structural member 3 is applied to the electronic device 100, the first exterior surface 3a of the composite structural member 3 may constitute at least part of the exterior surface of the electronic device 100. In addition, the film layer disposed on the first surface 31a includes, but is not limited to, an optical adjustment film layer 32.

Referring to fig. 7, the optical adjustment film 32 includes at least one high refractive index film 321 and at least one low refractive index film 322 stacked in sequence and alternately arranged, wherein the refractive index of the high refractive index film 321 is greater than that of the low refractive index film 322. Alternatively, both the high refractive index film 321 and the low refractive index film 322 are colorless transparent films. The material of the optical adjustment film 32 is a dielectric material. Specifically, the number of the high refractive index layers 321 may be one or more, and when the number of the high refractive index layers 321 is plural, the refractive indices of the plurality of high refractive index layers 321 may be the same or different. Likewise, the low refractive index film layer 322 may be one or more. When the plurality of low refractive index film layers 322 is provided, the refractive indices of the plurality of low refractive index film layers 322 may be the same or different. The film layer of the optical adjustment film layer 32 near the substrate 31 may be a high refractive index film layer 321 or a low refractive index film layer 322.

In this way, after the incident light irradiates the optical adjustment film 32, the light reflected and refracted by each film of the optical adjustment film 32 interferes with each other when exiting from the surface of the optical adjustment film 32 facing away from the substrate 31, so that the reflectivity of the light with a specific wavelength in the exiting light is enhanced, and the color of the first appearance surface 3a can be adjusted by the optical adjustment film 32, so that the first appearance surface 3a presents a preset color.

In practical applications, the thickness and refractive index of each film layer in the optical adjustment film layer 32 can be designed to make different emergent light interfere with each other, so as to achieve the purpose of adjusting the color of the first appearance surface 3 a. The specific structural design of the optical alignment film 32 may be performed on optical software (e.g., TFCale software, macleod software, etc.).

Referring to fig. 8, fig. 8 is a schematic diagram illustrating the operation of the optical adjustment film 32 in the composite structural member 3 shown in fig. 7. For ease of explanation, the optical adjustment film 32 will be described as including the first low refractive index film 322a, the first high refractive index film 321a, and the second high refractive index film 321 b. Specifically, the first high refractive index film 321a, the first low refractive index film 322a, and the second high refractive index film 321b are laminated in this order in the direction from the base material 31 to the optical adjustment film 32.

The incident light ray a1 is reflected by the surface of the side, away from the substrate 31, of the second high refractive index film 321b to obtain a first emergent light ray b1; the incident light ray a1 is refracted by the second high refractive index film 321b, reflected by the surface of the side, away from the substrate 31, of the first low refractive index film 322a, and refracted by the second high refractive index film 321b to obtain a second emergent light ray b2; the incident light ray a1 is refracted through the second high refractive index film layer 321b and the first low refractive index film layer 322a in sequence, reflected through the surface of one side, away from the substrate 31, of the first high refractive index film layer 321a, and then refracted through the first low refractive index film layer 322a and the second high refractive index film layer 321b in sequence to obtain a third emergent light ray b3; the incident light ray a1 is refracted by the second high refractive index film 321b, the first low refractive index film 322a and the first high refractive index film 321a in sequence, reflected by the first surface 31a of the substrate 31, and then refracted by the first high refractive index film 321a, the first low refractive index film 322a and the second high refractive index film 321b in sequence to obtain a fourth emergent light ray b4. The first outgoing light b1, the second outgoing light b2, the third outgoing light b3 and the fourth outgoing light b4 are mutually strengthened or weakened by the interference phenomenon of light, so that the purpose of adjusting the color of the first appearance surface 3a is achieved.

Specifically, in some embodiments, the L value, the a value, and the b value corresponding to the preset color in the Lab color space are L0, a0, and b0, respectively. Wherein L0 is greater than or equal to 85 and less than or equal to 92, a0 is greater than or equal to 2 and less than or equal to 5, b0 is greater than or equal to 22 and less than or equal to 30. That is, L0 is more than or equal to 85 and less than or equal to 92,2, a0 is more than or equal to 5, and b0 is more than or equal to 22 and less than or equal to 30. Illustratively, L0 may be 85, 86, 87, 88, 89, 90, 91, 92, etc. a0 may be 2, 3, 4, 5, etc. b0 may be 22, 23, 24, 25, 26, 27, 28, 29, 30, etc. In this way, the color of the first appearance surface 3a of the composite structural member 3 can be the same as that of gold, and the cost of the composite structural member 3 can be reduced while the first appearance surface 3a of the composite structural member 3 is in the true gold (i.e., 24K gold) texture.

On this basis, in order to improve the abrasion resistance, corrosion resistance, drop resistance, scratch resistance, and the like of the composite structural member 3, the vickers hardness (code HV) of the optical adjustment film layer 32 is 800 or more. Specifically, when the hardness of the composite structural member 3 is tested by the vickers indenter, the vickers hardness is greater than or equal to 800 when the surface indentation depth of the composite structural member 3 is about 200 nanometers. Illustratively, the vickers hardness of the optical tuning film layer 32 may be 800, 850, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200, 2500, 3000, etc.

In this way, in the composite structural member 3 in the embodiment of the present application, the appearance color of the composite structural member 3 is adjusted by the optical adjustment film layer 32, so that the appearance of the composite structural member 3 achieves the effect of true gold appearance color, thereby reducing the cost of the composite structural member 3 while ensuring the true gold texture of the composite structural member 3. Meanwhile, in the composite structural member 3 in the embodiment of the present application, the vickers hardness of the optical adjustment film layer 32 is set to be greater than or equal to 800, so that the wear resistance, corrosion resistance, anti-drop performance, scratch resistance and the like of the composite structural member 3 can be improved, and the service life of the composite structural member 3 can be prolonged.

In some embodiments, the optical tuning film layer 32 may be formed on the side of the substrate 31 toward which the first surface 31a faces by an atomic layer deposition (atomic layer deposition, ALD) process. The optical adjustment film layer 32 formed by the atomic layer deposition process has uniform thickness and is suitable for coating films with complex surfaces, and the blank areas which are not deposited on the composite structural member 3 can be effectively avoided, so that the appearance consistency of the composite structural member 3 is better, and the appearance texture of the composite structural member 3 can be further improved. In addition, the atomic layer deposition process has good environmental protection and is friendly to the environment.

In some embodiments, the material of the substrate 31 may be a metal. By way of example, the material of the substrate 31 may be stainless steel (e.g., 316L stainless steel, 304 stainless steel, etc.), aluminum alloy, titanium alloy, etc. Thus, the material of the base material 31 is easy to obtain and the molding is simple, and the cost and molding difficulty of the base material 31 can be reduced. In addition, the structural strength of the metal is higher, so that the wall thickness and the material consumption of the base material 31 can be reduced on the premise of ensuring that the structural strength of the base material 31 is unchanged, the internal space of the electronic equipment 100 can be increased, the layout of the electronic equipment 100 can be optimized, and the light and thin design and the miniaturized design of the electronic equipment 100 can be realized.

In other embodiments, the material of the substrate 31 may also be glass, ceramic or plastic. Thus, the weight of the base material 31 can be advantageously reduced, and the cost of the base material 31 can be further increased. In practical application, a suitable material for the base material 31 can be selected according to different application scenes and practical requirements of the composite structural material.

Referring to fig. 7 and 8, in some embodiments, the thickness t1 of the optical adjustment film 32 is greater than or equal to 1 micrometer (μm) and less than or equal to 3 micrometers. Specifically, the thickness of the optical modifying film layer 32 may be 1 micron, 1.5 microns, 2 microns, 2.5 microns, 3 microns, etc. The thickness of the optical adjustment film 32 is smaller, which is beneficial to reducing the overall thickness of the composite structural member 3.

In some embodiments, the high refractive index film 321 has a refractive index greater than or equal to 1.75. The low refractive index film 322 has a refractive index less than 1.75. In this way, the color of the first appearance surface 3a is conveniently adjusted to a preset color through the optical adjustment film layer 32, and the materials of the high refractive index film layer 321 and the low refractive index film layer 322 are easy to obtain, so that the processing difficulty of the composite structural member 3 can be reduced.

Further, the refractive index of the high refractive index film 321 is greater than or equal to 1.85 and less than or equal to 2.4. The low refractive index film layer 322 has a refractive index of 1.4 or more and 1.65 or less. In this way, the refractive index difference between the high refractive index film 321 and the low refractive index film 322 is larger, the more obvious the refractive effect of the interface between the adjacent high refractive index film 321 and low refractive index film 322 is, the reflection capability of the optical adjustment film 32 to a specific wavelength can be enhanced, so that the first appearance surface 3a of the composite structural member 3 can be adjusted to a preset color, and the appearance of the composite structural member 3 presents a real gold texture.

In some embodiments, the material of the high refractive index film 321 includes, but is not limited to, one or more of silicon nitride (Si 3N 4), aluminum nitride (AlN), titanium oxide (TiO 2), tantalum oxide (Ta 2O 5), niobium oxide (Nb 2O 5). The material of the low refractive index film layer 322 includes, but is not limited to, one or both of silicon oxide (SiO 2), aluminum oxide (Al 2O 3). The materials have excellent optical properties, can meet the refractive index requirement, have high vickers hardness, and can meet the hardness requirement of the optical adjustment film layer 32. In addition, precursors for these materials are readily available and can be processed by atomic layer deposition processes.

In some embodiments, the number of layers of the optical modifying film layer 32 is greater than or equal to 3 and less than or equal to 5. Specifically, the number of layers of the optical adjustment film layer 32 may be 3, 4, or 5. Thus, the structure of the optical adjustment film 32 can be simplified, and the difficulty in designing the optical adjustment film 32 can be reduced.

On the basis of any of the above embodiments, in order to reduce the thickness of the optical adjustment film 32 and simplify the processing process of the optical adjustment film 32, please refer to fig. 9, fig. 9 is a cross-sectional view of a partial structure of the composite structural member 3 according to other embodiments of the present application. The composite structure 3 comprises, in addition to the substrate 31 and the optical adjustment film layer 32, a color layer 33.

Specifically, referring to fig. 8, the color layer 33 is disposed between the first surface 31a and the optical adjustment film 32. The color layer 33 is used for providing basic reflection intensity or color for the preset color of the first appearance surface 3 a. Specifically, the color of the color layer 33 is a first color, and the corresponding L value, a value, and b value of the first color in the Lab color space are L1, a1, and b1, respectively, Δl is less than or equal to 20, Δa is less than or equal to 5, and Δb is less than or equal to 15; wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|.

That is, the absolute value of the difference of the L value corresponding to the first color and the preset color in the Lab color space is less than or equal to 20, the absolute value of the difference of the a value corresponding to the first color and the preset color in the Lab color space is less than or equal to 5, and the absolute value of the difference of the b value corresponding to the first color and the preset color in the Lab color space is less than or equal to 15.

Specifically, L0-20 is less than or equal to L1 and less than or equal to L0+20, a0-5 is less than or equal to a1 and less than or equal to a0+5, and b0-15 is less than or equal to b1 and less than or equal to b0+15. For example, when L0 is 85, L1 may be greater than or equal to 65 and less than or equal to 105. When a0 is 2, a1 may be greater than or equal to-3 and less than or equal to 7. When b0 is 25, b1 may be greater than or equal to 10 and less than or equal to 40.

In this way, the chromatic aberration between the first color and the preset color can be reduced, and the design difficulty of the optical adjustment film layer 32 can be reduced, so that the thickness of the optical adjustment film layer 32 can be reduced while the first appearance surface 3a is adjusted to the preset color, which is beneficial to reducing the overall thickness of the composite structural member 3.

On this basis, Δl may be less than or equal to 15, Δa may be less than or equal to 5, and Δb may be less than or equal to 10 in order to further reduce the color difference between the first color and the preset color.

In some embodiments, the material of the color layer 33 includes at least one of zirconium nitride (ZrN), titanium nitride (TiN), tantalum carbide (TaN), aluminum titanium nitride (AlTiN), hafnium nitride (HfN). The color layer 33 may be processed by a physical vapor deposition process. Specifically, the color layer 33 may be processed by a magnetron sputtering process. The color layer 33 processed by the above materials is substantially gold, that is, the first color is substantially gold, and may satisfy Δl less than or equal to 20, Δa less than or equal to 5, Δb less than or equal to 15, so that the thickness of the optical adjustment film layer 32 can be reduced while adjusting the first appearance surface 3a to a predetermined color, which is beneficial to reducing the overall thickness of the composite structural member 3. And the hardness of the materials is higher, so that the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member 3 can be improved.

For example, in some embodiments, referring to fig. 10, fig. 10 is a cross-sectional view of a partial structure of a color layer 33 and an optical adjustment film layer 32 in a composite structural member 3 according to some embodiments of the present application.

In this embodiment, the material of the color layer 33 is titanium nitride, the low refractive index film layer 322 includes a first low refractive index film layer 322a and a second low refractive index film layer 322b, the high refractive index film layer 321 includes a first high refractive index film layer 321a, a second high refractive index film layer 321b, and a third high refractive index film layer 321c, and the first high refractive index film layer 321a, the first low refractive index film layer 322a, the second high refractive index film layer 321b, the second low refractive index film layer 322b, and the third high refractive index film layer 321c are sequentially stacked in the direction from the base material 31 toward the optical adjustment film layer 32.

The first low refractive index film layer 322a and the second low refractive index film layer 322b are made of alumina (Al 2O 3), the thickness of the first low refractive index film layer 322a is more than or equal to 70 nanometers and less than or equal to 75 nanometers, and the thickness of the second low refractive index film layer 322b is more than or equal to 55 nanometers and less than or equal to 60 nanometers; the materials of the first high refractive index film layer 321a, the second high refractive index film layer 321b and the third high refractive index film layer 321c are titanium oxide (TiO 2), the thickness of the first high refractive index film layer 321a is greater than or equal to 55nm and less than or equal to 60nm, the thickness of the second high refractive index film layer 321b is greater than or equal to 75nm and less than or equal to 80nm, and the thickness of the third high refractive index film layer 321c is greater than or equal to 65nm and less than or equal to 70 nm.

Illustratively, the first low refractive index film layer 322a may have a thickness of 70nm, 71nm, 71.08nm, 72nm, 73nm, 74nm, 75nm, etc. The thickness of the second low refractive index film layer 322b may be 55nm, 56nm, 57nm, 58nm, 59nm, 59.11nm, 60nm, or the like. The thickness of the first high refractive index film layer 321a may be 55nm, 55.92nm, 56nm, 57nm, 58nm, 59nm, 60nm, or the like. The second high refractive index film layer 321b may have a thickness of 75nm, 75.92nm, 76nm, 77nm, 78nm, 79nm, 80nm, or the like. The thickness of the third high refractive index film layer 321c may be 65nm, 66nm, 67nm, 68nm, 69nm, 69.74nm, 70nm, or the like.

In this way, the structure of the optical adjustment film 32 can be simplified while the first appearance surface 3a of the composite structural member 3 presents a true gold texture, which is favorable for reducing the thickness of the optical adjustment film 32 and the processing difficulty of the optical adjustment film 32, and the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member 3 can be improved.

For another example, in other embodiments, referring to fig. 11, fig. 11 is a cross-sectional view of a partial structure of a color layer 33 and an optical adjustment film layer 32 in a composite structural member 3 according to some embodiments of the present application.

In this embodiment, the material of the color layer 33 is zirconium nitride, the low refractive index film layer 322 includes a first low refractive index film layer 322a, the high refractive index film layer 321 includes a first high refractive index film layer 321a and a second high refractive index film layer 321b, and the first high refractive index film layer 321a, the first low refractive index film layer 322a, and the second high refractive index film layer 321b are sequentially stacked in the direction from the substrate 31 toward the optical adjustment film layer 32. The material of the first low refractive index film layer 322a is alumina, and the thickness of the first low refractive index film layer 322a is greater than or equal to 100 nm and less than or equal to 120 nm; the first high refractive index film 321a and the second high refractive index film 321b are both made of chromium oxide, the thickness of the first high refractive index film 321a is greater than or equal to 55 nm and less than or equal to 60 nm, and the thickness of the second high refractive index film 321b is greater than or equal to 75 nm and less than or equal to 80 nm.

Illustratively, the first high refractive index film layer 321a may have a thickness of 100nm, 101nm, 105nm, 108nm, 110nm, 112nm, 115nm, 118nm, 120nm, etc. The thickness of the first low refractive index film layer 322a may be 55nm, 56nm, 57nm, 58nm, 59nm, 60nm, or the like. The second high refractive index film layer 321b may have a thickness of 75nm, 76nm, 77nm, 78nm, 79nm, 80nm, or the like.

Therefore, the structure of the optical adjustment film layer 32 can be simplified while the first appearance surface 3a of the composite structural member 3 presents a true gold texture, the thickness of the optical adjustment film layer 32 can be reduced, the processing difficulty of the optical adjustment film layer 32 can be reduced, and the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structure can be improved.

In some embodiments, the vickers hardness of the color layer 33 is greater than or equal to 800. Specifically, the vickers hardness of the color layer 33 may be 800, 850, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200, 2500, 3000, or the like. In this way, the hardness of the color layer 33 is relatively high, and the wear resistance, corrosion resistance, drop resistance, scratch resistance, and the like of the composite structural member 3 can be further improved.

In some embodiments, referring to fig. 9-11, the thickness t2 of the color layer 33 is greater than or equal to 80 nanometers (nm) and less than or equal to 3000nm. Specifically, the thickness t2 of the color layer 33 may be 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm, 550nm, 600nm, 650nm, 680nm, 700nm, 750nm, 1000nm, 1500nm, 2000nm, 2600nm, 2800nm, 3000nm, or the like. When the thickness of the color layer 33 is too small, the improvement of the abrasion resistance, corrosion resistance, drop resistance, scratch resistance of the composite structural member 3 is small, and the requirements cannot be satisfied. When the thickness of the color layer 33 is too large, the molding difficulty and the material cost of the color layer 33 are high. Moreover, the excessive or insufficient thickness of the color layer 33 can make the color difference between the first color and the predetermined color larger, which is not beneficial to reducing the thickness of the optical adjustment film 32.

Therefore, by setting the thickness of the color layer 33 to 80 nm-3000 nm, the wear resistance, corrosion resistance, drop resistance and scratch resistance of the composite structural member 3 can be ensured, the color difference between the first color and the preset color can be reduced, and meanwhile, the material consumption of the color layer 33 can be reduced, and the molding difficulty and the material consumption cost of the color layer 33 can be reduced.

Referring to fig. 12, fig. 12 is a cross-sectional view of a partial structure of a composite structural member 3 according to still other embodiments of the present application. In this embodiment, the composite structural member 3 includes a primer layer 34 in addition to the base material 31, the color layer 33, and the optical adjustment film layer 32. The primer layer 34 is disposed between the first surface 31a of the substrate 31 and the color layer 33. The material of the primer layer 34 includes at least one of aluminum, chromium, titanium, silicon, and silicon oxide. The primer layer 34 is used for increasing the adhesive force between the substrate 31 and the color layer 33, and can effectively prevent the color layer 33 from falling off from the first surface 31a of the substrate 31, so that the wear resistance of the composite structural member 3 can be further improved. Meanwhile, the bottom layer 34 can also provide a cut-off interface for stripping of defective film layers, so that the substrate 31 is prevented from being damaged by stripping liquid.

Wherein the number of layers of the primer layer 34 may be one or more. In practical applications, the specific materials and number of layers of the primer layer 34 may be selected according to the materials of the substrate 31. For example, when the material of the base material 31 is stainless steel, the primer layer 34 may be provided as a layer, and the material of the primer layer 34 includes chrome silicon. When the material of the base material 31 is an aluminum alloy, the primer layer 34 is provided in two layers. In this case, the primer layer 34 includes a first primer layer and a second primer layer. The first primer layer is disposed on the first surface 31a of the substrate 31, and the second primer layer is disposed on a surface of the first primer layer facing away from the substrate 31. The material of the first primer layer comprises metallic aluminum and the material of the second primer layer comprises metallic chromium (Gr). When the material of the base material 31 is a titanium alloy, the underlayer 34 may be provided as a layer, and the material of the underlayer 34 includes metallic titanium. When the material of the substrate 31 is glass or ceramic, the primer layer 34 may be provided as a layer, and the material of the primer layer 34 includes silicon oxide (SiO 2). When the material of the base material 31 is plastic, the primer layer 34 may be provided as a layer, and the primer layer 34 includes elemental silicon (Si).

In some embodiments, referring to fig. 12, the thickness t3 of the primer layer 34 is greater than or equal to 50 nanometers and less than or equal to 500 nanometers. Specifically, the thickness t3 of the primer layer 34 may be 50nm, 60nm, 70nm, 100nm, 120nm, 150nm, 180nm, 200nm, 300nm, 350nm, 400nm, 450nm, 500nm, etc. In this way, the thickness of the primer layer 34 is moderate, which can increase the adhesion between the color layer 33 and the substrate 31, and at the same time is beneficial to reduce the overall thickness of the composite structural member 3.

In order to provide the appearance surface of the composite structural member 3 with the anti-fingerprint performance on the basis of any of the above embodiments, in some embodiments, please refer to fig. 13, fig. 13 is a cross-sectional view of a partial structure of the composite structural member 3 according to still other embodiments of the present application. In this embodiment, the composite structural member 3 further comprises an anti-fingerprint (AF) layer. The anti-fingerprint layer 35 of this embodiment may be combined with any of the embodiments described above.

Referring to fig. 13, the anti-fingerprint layer 35 is disposed on a surface of the optical adjustment film 32 facing away from the substrate 31. The anti-fingerprint layer 35 comprises an organic or inorganic material with low surface energy and has hydrophobic and oleophobic properties, so that the surface of the composite structural member 3 is easy to clean, and the anti-fingerprint performance is better. Specifically, the material of the anti-fingerprint layer 35 includes, but is not limited to, fluorine-containing compounds. For example, the material of the fingerprint prevention layer 35 may be Polytetrafluoroethylene (PTFE), chlorofluoro phenylurea (cloflucarban), or the like. The fluorine-containing compound has lower surface energy, and can achieve the aims of hydrophobicity, oleophobicity and fingerprint residue resistance.

The thickness of the finger-proof layer 35 is greater than or equal to 10nm and less than or equal to 30 nm. Illustratively, the anti-fingerprint layer 35 may have a thickness of 10nm, 12nm, 15nm, 16nm, 18nm, 20nm, 22nm, 25nm, 28nm, 29nm, 30nm, etc. In this way, the protective effect of the fingerprint-preventing layer 35 is ensured, and the overall thickness of the composite structural member 3 is also considered.

On this basis, in order to improve the adhesion between the anti-fingerprint layer 35 and the optical adjustment film layer 32, please continue to refer to fig. 13, a transition layer 36 is disposed between the optical adjustment film layer 32 and the anti-fingerprint layer 35. The material of the transition layer 36 may be silicon oxide (SiO 2).

The thickness of the transition layer 36 is greater than or equal to 8 nanometers and less than or equal to 15 nanometers. By way of example, the thickness of the transition layer 36 may be 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, etc. Thus, the adhesion between the anti-fingerprint layer 35 and the optical adjustment film layer 32 can be improved, and the overall thickness of the composite structural material member can be considered.

Of course, it will be appreciated that in other embodiments, the composite structural member 3 may not include the transition layer 36 described above.

The embodiment of the application also provides a processing method of the composite structural member 3, refer to fig. 14, and fig. 14 is a flowchart of a processing method of the composite structural member 3 provided in some embodiments of the application. The composite structural member 3 may be the composite structural member 3 in any of the above embodiments. The processing method of the composite structural member 3 comprises the following steps:

Step S100: providing a substrate 31, the substrate 31 comprising a first surface 31a;

the material of the substrate 31 may be metal, glass, ceramic or plastic.

Step S200: forming an optical adjustment film layer 32 on a side of the first surface 31a of the substrate 31 facing the first surface, and enabling the first appearance surface 3a of the composite structural member 3 to be in a preset color, wherein the preset color corresponds to L value, a value and b value in a Lab color space, L0 is greater than or equal to 85 and less than or equal to 90, a0 is greater than or equal to 2 and less than or equal to 5, and b0 is greater than or equal to 22 and less than or equal to 30; the optical adjustment film layer 32 includes at least one high refractive index film layer 321 and at least one low refractive index film layer 322 which are sequentially laminated and alternately arranged, the refractive index of the high refractive index film layer 321 is greater than that of the low refractive index film layer 322, and the vickers hardness of the optical adjustment film layer 32 is greater than or equal to 800; the first appearance surface 3a is oriented in the same direction as the first surface 31 a.

The optical adjustment film 32 may be directly formed on the first surface 31a of the substrate 31, or may be formed on the surface of another film located on the first surface 31a of the substrate 31.

In this way, the wear resistance, corrosion resistance, drop resistance, scratch resistance and the like of the composite structural member 3 can be improved while the true gold texture of the composite structural member 3 is ensured, and the service life of the composite structural member 3 can be prolonged. Meanwhile, the processing method is simple in process and low in processing cost.

In some embodiments, the optical modifier film 32 may be fabricated using an atomic layer deposition process. In this way, the thickness of the optical adjustment film layer 32 can be uniform, the optical adjustment film layer is suitable for coating films with complex surfaces, the existence of blank areas which are not deposited on the composite structural member 3 can be effectively avoided, the appearance consistency of the composite structural member 3 is better, and the appearance texture of the composite structural member 3 can be further improved. In addition, the atomic layer deposition process has good environmental protection and is friendly to the environment.

It should be noted that, in the optical adjustment film 32 of the present embodiment, the refractive index, thickness, material, overall thickness, number of layers, specific structure, etc. of each film may be designed with reference to the optical adjustment film 32 of any embodiment of the present application, and will not be described herein.

In other embodiments, referring to fig. 15, fig. 15 is a flowchart illustrating a method for processing a composite structural member 3 according to other embodiments of the present disclosure. The processing method of the composite structural member 3 in this embodiment is different from the processing method in the embodiment shown in fig. 14 in that, in the processing method of this embodiment, before forming the optical adjustment film layer 32 on the side facing the first surface 31a of the base material 31, it further includes:

Step S101: forming a color layer 33 on a side of the substrate 31 facing the first surface 31a, wherein the color of the color layer 33 is a first color, and the corresponding values of L, a and b of the first color in the Lab color space are L1, a1 and b1 respectively, deltaL is less than or equal to 20, deltaa is less than or equal to 5 and Deltab is less than or equal to 15; wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|.

Specifically, the color layer 33 may be formed on the side of the substrate 31 toward which the first surface 31a faces by a PVD process (specifically, a magnetron sputtering process). Thus, the color layer 33 has high hardness and excellent corrosion resistance, drop resistance and scratch resistance.

The material, thickness, vickers hardness, etc. of the color layer 33 in this embodiment may be designed with reference to the color layer 33 in any embodiment of the present application, and will not be described herein.

In still other embodiments, referring to fig. 16, fig. 16 is a flowchart illustrating a method for processing a composite structural member 3 according to still other embodiments of the present application. The processing method of the composite structural member 3 in this embodiment is different from the processing method in the embodiment shown in fig. 15 in that, in the processing method of this embodiment, before forming the color layer 33 on the side toward which the first surface 31a of the base material 31 faces, it further includes:

Step S102: a primer layer 34 is formed on the first surface 31a of the substrate 31.

Specifically, the underlayer 34 may be formed on the first surface 31a of the substrate 31 by a PVD process (specifically, a magnetron sputtering process). In this way, the adhesion between the substrate 31 and the color layer 33 can be improved, and the color layer 33 can be effectively prevented from falling off from the first surface 31a of the substrate 31, so that the wear resistance of the composite structural member 3 can be further improved. Meanwhile, the bottom layer 34 can also provide a cut-off interface for stripping of defective film layers, so that the substrate 31 is prevented from being damaged by stripping liquid.

The specific material of the primer layer 34 may be selected according to the material of the substrate 31.

In some embodiments, referring to fig. 16, after step S200, the processing method further includes the following step S300.

Step S300: an anti-fingerprint layer 35 is formed on the surface of the optical adjustment film 32 remote from the substrate 31.

Wherein the material of the anti-fingerprint layer 35 includes, but is not limited to, fluorine-containing compounds. For example, polytetrafluoroethylene (PTFE) and chlorofluorophenylurea (cloflucarban) may be used. The fluorine-containing compound has lower surface energy, and can achieve the aims of hydrophobicity, oleophobicity and fingerprint residue resistance.

In some embodiments, step S300 includes: the surface of the optical adjustment film 32 facing away from the substrate 31 is provided with an anti-fingerprint layer 35 by a PVD process (which may specifically be a vacuum evaporation process). The anti-fingerprint layer 35 formed by the vacuum evaporation process has higher hardness and better scratch resistance.

Specifically, in order to obtain the anti-fingerprint layer 35, the plating parameters in step S300 may be: the coating current was 260A, the flow rate of argon (Ar) was 220sccm (volume flow unit), the flow rate of oxygen (O2) was 220sccm, and the coating time was 3 minutes, thereby obtaining the fingerprint-preventing layer 35 having a thickness of 10nm to 30 nm.

In some embodiments, referring to fig. 16, after step S200 and before step S300, the processing method may further include: step S201: a transition layer 36 is formed on the surface of the optical adjustment film 32 remote from the substrate 31. The material of the transition layer 36 may be silicon oxide (SiO 2). Specifically, the transition layer 36 may be formed on a surface of the optical tuning film layer 32 facing away from the substrate 31 by a PVD process (specifically, a magnetron sputtering process). In this way, the adhesion between the anti-fingerprint layer 35 and the optical adjustment film 32 can be improved, and the anti-fingerprint layer 35 can be effectively prevented from falling off the optical adjustment film 32.

It is understood that step S300 and step S201 in the embodiments of the present application may be applied to the processing method in any of the embodiments of the present application. In addition, the processing method in the embodiment of the present application may not include step S201, or may not include step S300 and step S201.

Two specific embodiments of the composite structural member 3 and its method of processing in the present application are described below.

Example 1

Referring to fig. 17, fig. 17 is a cross-sectional view of a partial structure of a composite structural member 3 according to some embodiments of the present application. The composite structural member 3 includes a base material 31, a primer layer 34, a color layer 33, an optical adjustment film layer 32, a transition layer 36, and an anti-fingerprint layer 35, which are laminated in this order.

In this embodiment, the material of the substrate 31 may be stainless steel, the material of the primer layer 34 may be chrome silicon, the material of the color layer 33 may be titanium nitride, the material of the transition layer 36 may be silicon oxide, and the material of the anti-fingerprint layer 35 may be polytetrafluoroethylene.

The high refractive index film 321 in the optical adjustment film 32 may be a titanium oxide (TiO 2) layer, and the low refractive index film 322 may be an aluminum oxide (Al 2O 3) layer. The high refractive index film 321 includes a first high refractive index film 321a, a second high refractive index film 321b, and a third high refractive index film 321c, and the low refractive index film 322 includes a first low refractive index film 322a and a second low refractive index film 322b. The first high refractive index film 321a, the first low refractive index film 322a, the second high refractive index film 321b, the second low refractive index film 322b, and the third high refractive index film 321c are laminated in this order in the direction from the base material 31 to the optical adjustment film 32.

Referring to fig. 18, fig. 18 is a flowchart illustrating a processing method of the composite structural member 3 shown in fig. 17. Specifically, the processing method of the composite structural member 3 includes:

step S100a: providing a substrate 31, the substrate 31 comprising a first surface 31a; the material of the base material 31 is stainless steel (e.g., 316L stainless steel);

step S103a, cleaning the substrate 31 to remove pollutants and adsorbed gas on the surface of the substrate 31;

specifically, step S103a includes: the polished substrate 31 is subjected to pretreatment such as alkaline wax removal and oil removal at a high temperature (80 ℃) and then is subjected to drying treatment (for example, suspension drying is performed), the drying temperature is 60 ℃, the drying time is 40-60 minutes, and then the dried substrate 31 is placed into a PVD furnace for argon ion cleaning. The specific cleaning process can be as follows: the background vacuum in the PVD furnace was about 1 x 10 ^-3 About Pa, introducing Ar gas to 0.4 Pa-0.6 Pa (e.g. 0.5 Pa), and generating Ar with hot wire plasma source ⁺ Ar under the bias of 450-550V (500V for example) of plasma ⁺ The surface of the sample is ion-cleaned for 8 to 15 minutes (e.g., 10 minutes) to remove contaminants and adsorbed gas from the surface of the substrate 31.

Step S102a: a magnetron sputtering process is used to form a primer layer 34 on the first surface 31a, and the primer layer 34 is a chrome silicon primer layer.

Specifically, step S102a includes: opening a target in the PVD furnace, and introducing argon gas to deposit a chromium silicon primer layer 34 on the first surface 31a of the base material 31 in the PVD furnace, wherein the mass fraction of chromium in the chromium silicon is more than or equal to 60% and less than or equal to 90%; the technological parameters are as follows: vacuum degree is adjusted to 5 x 10 ^-3 Pa, sample bias voltage is-40V to-180V, argon is introduced, air pressure is 2Pa to 6Pa, sample temperature is controlled at 200 ℃ to 300 ℃, target material is a chromium silicon target, target material current is 70A to 110A, deposition time is 120min, and the chromium silicon priming layer is prepared.

Step S101a: a color layer 33 is formed on the surface of the primer layer 34 facing away from the substrate 31, the color layer 33 being a titanium nitride (TiN) layer.

Specifically, step S101a includes: opening a target material, introducing argon and nitrogen, and depositing a titanium nitride layer, wherein the technological parameters are as follows: vacuum degree is adjusted to 5 x 10 ^-3 Pa, sample bias voltage is-40V to-180V, argon is introduced, air pressure is 0.2Pa to 0.6Pa, sample temperature is controlled at 80 ℃ to 120 ℃, target material is titanium target, target material current is 70A to 110A, deposition time is 60min, and the titanium nitride layer is prepared. The titanium nitride layer is gold, the color of the titanium nitride layer (i.e., the first color) corresponds to an L value of 72.41 (i.e., l1= 72.41), an a value of 2.5 (i.e., a1=2.5), and a b value of 28.41 (i.e., b1= 28.41) in the Lab color space. Δl is less than or equal to 19.59, Δa is less than or equal to 2.5, Δb is less than or equal to 6.41, satisfying the following conditions: deltaL is less than or equal to 20, deltaa is less than or equal to 5, deltab is less than or equal to 15.

Step S200a: forming an optical adjustment film layer 32 on a surface of the color layer 33 facing away from the substrate 31;

specifically, the specific structure of the optical alignment film 32 may be first designed, which may be performed on optical film software (e.g., TFCale software, macleod software, etc.). The material of the low refractive index film layer (L) 322 is alumina (Al 2O 3), the material of the high refractive index film layer (H) 321 is titanium oxide (TiO 2), an initial film system HL is formed in the optical film software, a film system formed by stacking L and H is formed, and then the band optimization condition is input in a continuous target, so that the transmittance is ensured to meet the requirement; then, inputting L0, a0 and b0 values corresponding to preset colors in a Lab color space into a color target, ensuring that the colors of the optical adjustment film 32 are colorless, and obtaining a specific structure of the optical adjustment film 32 after a series of optimal designs as shown in Table 1:

TABLE 1

Film material	TiO2	Al2O3	TiO2	Al2O3	TiO2
						Film thickness (nm)	55.92	71.08	75.92	59.11	69.74

Specifically, the thickness of the first high refractive index film 321a is 55.92nm, the thickness of the first low refractive index film 322a is 71.08nm, the thickness of the second high refractive index film 321b is 75.92nm, the thickness of the second low refractive index film 322b is 59.11nm, and the thickness of the third high refractive index film 321c is 69.74nm.

The high refractive index film 321 and the low refractive index film 322 may be fabricated by Atomic Layer Deposition (ALD).

Illustratively, the titanium oxide layer may be prepared by: titanium tetrachloride and water vapor are used as reaction sources, the temperature of the sources is 50 to 100 ℃ (e.g., 60 ℃), the growth temperature is 180 to 240 ℃ (e.g., 210 ℃), and the reaction base pressure is 100 to 150Pa (e.g., 150Pa, 120Pa, etc.). One standard ALD cycle for growing a titanium oxide layer (also referred to as a titanium oxide film) is as follows: titanium tetrachloride is introduced into the reaction cavity, and the pulse time is 0.3s; argon purging for 3s to remove reaction residues and gaseous byproducts; H2O is introduced, and the pulse time is 0.3 s-0.6 s (for example, 0.6 s); argon is purged for 2s to 4s (e.g., 3 s). And circulating until the thickness of the film reaches the design thickness.

The preparation process of the alumina layer can be as follows: an alumina layer (also referred to as an alumina film) is reactive deposited using Trimethylaluminum (TMA) as a precursor. The carrier gas of oxygen and TMA is high-purity nitrogen, and the volume flow is respectively controlled to be 100cm ³ /min～200cm ³ /min (e.g. 150 cm) ³ /min) and 35cm ³ /min～65cm ³ /min (e.g. 50 cm) ³ /min). The cavity deposition temperature of ALD is 60 ℃, and the reaction cavity base pressure is kept between 500Pa and 1000Pa (e.g., 700 Pa). At a specific power, the TMA pulse time was 0.1s, the argon purge time was 3.0s, the oxygen plasma pulse time was 1 s-3 s (e.g., 3 s), and the argon purge time was 2 s-7 s (e.g., 5 s). And circulating until the film layer reaches the design thickness.

Step S201a: a transition layer 36 is formed on the surface of the optical adjustment film layer 32 facing away from the substrate 31, the transition layer 36 being a silicon oxide (SiO 2) layer.

Specifically, the transition layer 36 may be formed on a surface of the optical tuning film layer 32 facing away from the substrate 31 by a PVD process (specifically, a magnetron sputtering process). In order to obtain the silicon oxide transition layer, the set coating parameters are as follows: sputtering power of silicon target: 8KW, the flow rate of argon (Ar) is 250sccm, the flow rate of oxygen (O2) is 120sccm (volume flow unit), and the coating time is 2min, so that the silicon oxide transition layer with the thickness of 8 nm-13 nm is obtained.

Step S300a: an anti-fingerprint layer 35 is formed on the surface of the transition layer 36 facing away from the optical modifier film 32.

Specifically, the anti-fingerprint layer 35 may be disposed on the surface of the optical adjustment film 32 facing away from the substrate 31 by a PVD process (specifically, a vacuum evaporation process).

In order to obtain the anti-pollution fingerprint-preventing layer 35, the poly (perfluoroether) siloxane is used as a raw material, and the set coating parameters are as follows: the coating current was 260A, the flow rate of argon (Ar) was 220sccm (volume flow unit), the flow rate of oxygen (O2) was 220sccm, and the coating time was 3 minutes, thereby obtaining the fingerprint-preventing layer 35 having a thickness of 10nm to 30 nm.

In the composite structural member 3 prepared by the processing method in this embodiment, the color of the first appearance surface 3a corresponds to an L value of 90.63 (i.e., l0=90.63) in the Lab color space, an a value of 3.45 (i.e., a0=3.45), and a b value of 28.79 (i.e., b0=28.79), which satisfies the following conditions: l0 is more than or equal to 85 and less than or equal to 92,2, a0 is more than or equal to 5, b0 is more than or equal to 22 and less than or equal to 30, so that the appearance of the composite structural member 3 can show true gold texture. In addition, the hardness of the composite structural member 3 was measured by using a vickers indenter, and the vickers hardness was 1250 when the surface indentation depth of the composite structural member 3 was about 200 nm. In addition, the composite structural member 3 has a high hardness and is excellent in corrosion resistance, wear resistance and scratch resistance.

Specifically, when the salt spray corrosion test is performed on the composite structural member 3, after the composite structural member 3 is corroded in salt spray for 96 hours, the surface of the composite structural member 3 is visually observed to have no pitting marks, and therefore the corrosion resistance of the composite structural member 3 is high. When the abrasion resistance test is performed on the composite structural member 3, the surface of the composite structural member 3 is free from obvious scratches, film peeling, speckles, fading and other adverse phenomena after 48h vibration grinding (equivalent to two years of actual wear), and the color of the first appearance surface 3a of the composite structural member 3 is less than 1.5NBS and has no visual difference after 48h vibration grinding. It can be seen that the composite structural member 3 has a relatively high resistance to wear.

It should be noted that, in the embodiment of the present application, the calculation formula of Δe is: ΔE= [ (L0-L2) ² +(a0-a2) ² +(b0-b2) ² ] ^1/2 Wherein L0, a0, b0 are the L value, a value, and b value corresponding to the measured first appearance surface 3a in the Lab color space before the abrasion test, and L2, a2, b2 are the L value, a value, and b value corresponding to the measured first appearance surface 3a in the Lab color space after the abrasion test.

The salt fog test comprises the following steps: in a closed environment with the temperature of 35+/-2 ℃ and the humidity of more than 85%, continuously spraying the saline on the sample by using NaCl solution (with the pH value in the range of 6.5-7.2) with the mass ratio of 5+/-1%.

The wear resistance test may be performed in a vibratory friction apparatus. By way of example, the model of the vibratory friction apparatus may be: r180/530TE-30.

It will be appreciated that in other embodiments, the composite structural member 3 may be manufactured using other processing methods.

Example 2

Referring to fig. 19, fig. 19 is a cross-sectional view of a partial structure of a composite structural member 3 according to other embodiments of the present application. The composite structural member 3 includes a base material 31, a first primer layer 341, a second primer layer 342, a color layer 33, an optical adjustment film layer 32, a transition layer 36, and an anti-fingerprint layer 35, which are sequentially laminated.

In this embodiment, the material of the substrate 31 is aluminum alloy, the material of the first primer layer 341 is aluminum silicon, and the material of the second primer layer 342 is chrome silicon. The material of the color layer 33 is zirconium nitride, the material of the transition layer 36 is silicon oxide, and the material of the fingerprint prevention layer 35 is polytetrafluoroethylene.

The high refractive index film 321 in the optical adjustment film 32 is a zirconia (ZrO 2) layer, and the low refractive index film 322 is an alumina (Al 2O 3) layer. The high refractive index film 321 includes a first high refractive index film 321a and a second high refractive index film 321b, and the low refractive index film 322 includes a first low refractive index film 322a. The first high refractive index film 321a, the first low refractive index film 322a, and the second high refractive index film 321b are laminated in this order in the direction from the base material 31 to the optical adjustment film 32.

Referring to fig. 20, fig. 20 is a flowchart illustrating a processing method of the composite structural member 3 shown in fig. 19. Specifically, the processing method of the composite structural member 3 includes:

step S100b: providing a substrate 31, the substrate 31 comprising a first surface 31a; the material of the base material 31 is an aluminum alloy;

step S103b, cleaning the substrate 31 to remove pollutants and adsorbed gas on the surface of the substrate 31;

the specific processing method of step S103b may be the same as that of step S103a, and will not be described in detail here.

Step S102b: forming a primer layer 34 on the first surface 31a by using a magnetron sputtering process; the primer layer 34 includes a first primer layer 341 and a second primer layer 342, wherein the first primer layer 341 is an aluminum-silicon primer layer, and the second primer layer 342 is a chrome-silicon primer layer.

Specifically, step S102b includes:

step S102b1: a first primer layer 341 is formed on the first surface 31 a: opening a target in the PVD furnace, and introducing argon gas to deposit a first primer layer 341 on the first surface 31a of the substrate 31 in the PVD furnace, wherein the ratio of the mass fraction of aluminum in the aluminum silicon to the mass fraction of silicon is 3:7; the technological parameters are as follows: vacuum level was adjusted to 3 x 10 ^-3 Pa, sample bias voltage is-40V to-80V, argon is introduced, air pressure is 0.2Pa to 1.0Pa, sample temperature is controlled at 200 ℃ to 300 ℃, target material is aluminum silicon target, target material current is 70A to 110A, deposition time is 20min, and a first priming layer 341 (namely aluminum silicon priming layer) is prepared.

Step S102b2: a second primer layer 342 is formed on the surface of the first primer layer 341 facing away from the substrate 31: opening a target in the PVD furnace, and introducing argon gas to form a second primer layer 342 on the surface of the first primer layer 341, which is far away from the base material 31, wherein the ratio of the mass fraction of chromium in the chromium silicon to the mass fraction of silicon is 9:1, a step of; the technological parameters are as follows: vacuum level was adjusted to 3 x 10 ^-3 Pa, sample bias voltage is-40V to-180V, argon is introduced, air pressure is 2 Pa-6 Pa, sample temperature is controlled at 200 ℃ to 300 ℃, target material is chromium silicon target, target material current is 70A to 110A,the deposition time was 120 minutes to produce a second primer layer 342 (i.e., a chrome silicon primer layer).

Step S101b: a color layer 33 is formed on the surface of the primer layer 34 facing away from the substrate 31, the color layer 33 being a zirconium nitride (ZrN) layer. That is, the material of the color layer 33 is zirconium nitride.

Specifically, step S101b includes: opening a target, introducing argon and nitrogen, and depositing a zirconium nitride layer, wherein the technological parameters are as follows: vacuum degree is adjusted to 5 x 10 ^-3 Pa, sample bias voltage is-40V to-180V, argon is introduced, air pressure is 0.2Pa to 0.6Pa, sample temperature is controlled at 80 ℃ to 120 ℃, target material is zirconium target, target material current is 70A to 110A, deposition time is 60min, and the zirconium nitride layer is prepared. The zirconium nitride layer was gold colored, the color of the zirconium nitride (i.e., the first color) corresponding to an L value of 85.62 (i.e., l1= 85.62), an a value of 3.4 (i.e., a1=3.4), and a b value of 18.12 (i.e., b1=18.12) in the Lab color space. Δl is less than or equal to 6.38, Δa is less than or equal to 1.6, Δb is less than or equal to 11.88, satisfying the following conditions: deltaL is less than or equal to 20, deltaa is less than or equal to 5, deltab is less than or equal to 15.

Step S200b: forming an optical adjustment film layer 32 on a surface of the color layer 33 facing away from the substrate 31;

specifically, the specific structure of the optical alignment film 32 may be first designed, which may be performed on optical film software (e.g., TFCale software, macleod software, etc.). The material of the low refractive index film layer (L) 322 is alumina (Al 2O 3), the material of the high refractive index film layer (H) 321 is zirconia (ZrO 2), an initial film system HL is formed in the optical film software, a film system formed by stacking L and H is formed, and then band optimization conditions are input in a continuous target to ensure that the transmittance meets the requirement; then, inputting L0, a0 and b0 values corresponding to preset colors in a Lab color space into a color target, ensuring that the colors of the optical adjustment film 32 are colorless, and obtaining a specific structure of the optical adjustment film 32 after a series of optimal designs as shown in Table 2:

TABLE 2

Film material	ZrO2	Al2O3	ZrO2
				Film thickness (nm)	55.92	110	75.92

Specifically, in the present embodiment, the thickness of the first high refractive index film 321a is 55.92nm, the thickness of the first low refractive index film 322a is 110nm, and the thickness of the second high refractive index film 321b is 75.92nm.

Illustratively, the zirconia layer may be prepared by: as reaction sources, tetra (dimethylamino) zirconium (TDMAZ) and steam are used, the temperature of the sources is 40-80 ℃ (e.g. 60 ℃), the growth temperature is 85 ℃, and the reaction base pressure is 100 Pa-150 Pa (e.g. 130Pa, 133Pa, etc.). One standard ALD grown zirconia layer cycle is as follows: introducing the TDMAZ into the reaction cavity, wherein the pulse time is 0.2s; argon purging for 2s to remove reaction residues and gaseous byproducts; H2O is introduced, and the pulse time is 0.5 s-0.8 s (for example, 0.6 s); argon is purged for 7s to 11s (e.g., 9 s). And circulating until the film layer reaches the design thickness.

The preparation process of the alumina layer can be as follows: an alumina layer (also referred to as an alumina film) is reactive deposited using Trimethylaluminum (TMA) as a precursor. The carrier gas of oxygen and TMA is high-purity nitrogen, and the volume flow is respectively controlled to be 120cm ³ /min～180cm ³ /min (e.g. 150 cm) ³ /min) and 40cm ³ /min～80cm ³ /min (e.g. 50 cm) ³ /min). The chamber deposition temperature of ALD is 50 ℃ -90 ℃ (e.g., 60 ℃), and the reaction chamber base pressure is maintained at 500 Pa-1000 Pa (e.g., 700 Pa). At a specific power, the TMA pulse time is 0.1s, the argon gas cleaning time is 2 s-5 s (e.g. 3 s), the oxygen plasma pulse time is 2 s-5 s (e.g. 3 s), and the argon gas cleaning time is 4 s-10 s (e.g. 5 s). And circulating until the film layer reaches the design thickness.

Step S201b: forming a transition layer 36 on a surface of the optical adjustment film layer 32 facing away from the substrate 31, the transition layer 36 being a silicon dioxide (SiO 2) layer; that is, the material of the transition layer 36 is silicon dioxide.

The specific procedure of step S201b may be the same as step S201a, and will not be described in detail here.

Step S300b: an anti-fingerprint layer 35 is formed on the surface of the transition layer 36 facing away from the optical modifier film 32. The specific process of step S300b may be the same as step S300a and will not be described in detail herein.

In the composite structural member 3 prepared by the processing method in this embodiment, the color of the first appearance surface 3a corresponds to an L value of 85.47 (i.e., l0=85.47), an a value of 2.86 (i.e., a0=2.86), and a b value of 26.79 (i.e., b0= 26.79) in the Lab color space, so that the following conditions are satisfied: l0 is more than or equal to 85 and less than or equal to 92,2, a0 is more than or equal to 5, b0 is more than or equal to 22 and less than or equal to 30, so that the appearance of the composite structural member 3 can show true gold texture. In addition, the hardness of the composite structural member 3 was measured by using a vickers indenter, and the vickers hardness was 1250 when the surface indentation depth of the composite structural member 3 was about 200 nm. In addition, the composite structural member 3 has a high hardness and is excellent in corrosion resistance, wear resistance and scratch resistance.

Specifically, when the salt spray corrosion test is performed on the composite structural member 3, after the composite structural member 3 is corroded in salt spray for 96 hours, the surface of the composite structural member 3 is visually observed to have no pitting marks, and therefore the corrosion resistance of the composite structural member 3 is high. When the abrasion resistance test is performed on the composite structural member 3, the surface of the composite structural member 3 is free from obvious scratches, film peeling, speckles, fading and other adverse phenomena after 48h vibration grinding (equivalent to two years of actual wear), and the color of the first appearance surface 3a of the composite structural member 3 is less than 0.5NBS with no visual difference after 48h vibration grinding. It can be seen that the composite structural member 3 has a relatively high resistance to wear.

When the composite structural member 3 provided by the application is applied to electronic equipment 100 such as a mobile phone, a tablet personal computer and a watch and a decorative member, the color of the appearance surface (namely the surface forming the outer surface of the electronic equipment 100) is the same as that of gold, so that the electronic equipment 100, the decorative member and the like have real gold texture, and meanwhile, the cost of the electronic equipment 100 and the decorative member is reduced. Moreover, the composite structural member 3 has high vickers hardness, can improve the corrosion resistance, wear resistance, drop resistance and scratch resistance of the electronic equipment 100 and the decorative member, and has better application effect and prospect.

In the description of the present specification, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. A composite structural member comprising:

a substrate comprising a first surface;

the optical adjustment film layer is arranged on one side, facing the first surface, of the optical adjustment film layer, the optical adjustment film layer comprises at least one high-refractive-index film layer and at least one low-refractive-index film layer which are sequentially and alternately arranged, the refractive index of the high-refractive-index film layer is larger than that of the low-refractive-index film layer, and the Vickers hardness of the optical adjustment film layer is larger than or equal to 800;

The composite structural member comprises a first appearance surface, the orientation of the first appearance surface is the same as that of the first surface, the optical adjusting film layer is used for adjusting the color of the first appearance surface so that the first appearance surface is in a preset color, the corresponding L value, a value and b value of the preset color in a Lab color space are respectively L0, a0 and b0, L0 is greater than or equal to 85 and less than or equal to 92, a0 is greater than or equal to 2 and less than or equal to 5, and b0 is greater than or equal to 22 and less than or equal to 30.

2. The composite structural member of claim 1 wherein the high refractive index film layer has a refractive index greater than or equal to 1.75; the low refractive index film layer has a refractive index of less than 1.75.

3. The composite structural member of claim 1 or 2 wherein the material of the high refractive index film layer comprises at least one of silicon nitride, aluminum nitride, titanium oxide, tantalum oxide, niobium oxide; and/or

The material of the low refractive index film layer comprises at least one of silicon oxide and aluminum oxide.

4. A composite structural member according to any one of claims 1 to 3 wherein the thickness of the optical modifying film layer is greater than or equal to 1 micron and less than or equal to 3 microns.

5. The composite structural member of any one of claims 1 to 4 wherein the number of optical modifying film layers is greater than or equal to 3 and less than or equal to 5.

6. The composite structural member of any one of claims 1 to 5, further comprising a color layer disposed between the first surface and the optical adjustment film layer, the color of the color layer being a first color having corresponding L, a, b values in Lab color space of L1, a1, and b1, respectively, Δl being less than or equal to 20, Δa being less than or equal to 5, Δb being less than or equal to 15;

wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|.

7. The composite structural member of claim 6 wherein the material of the color layer comprises at least one of zirconium nitride, titanium nitride, tantalum carbide, titanium aluminum nitride, hafnium nitride.

8. The composite structural member of claim 6 or 7 wherein the vickers hardness of the color layer is greater than or equal to 800.

9. The composite structural member of any one of claims 6 to 8 wherein the thickness of the color layer is greater than or equal to 80 nanometers and less than or equal to 3000 nanometers.

10. The composite structural member according to any one of claims 6 to 9, wherein the material of the color layer is titanium nitride, the low refractive index film layer includes a first low refractive index film layer and a second low refractive index film layer, the high refractive index film layer includes a first high refractive index film layer, a second high refractive index film layer, and a third high refractive index film layer, and the first high refractive index film layer, the first low refractive index film layer, the second high refractive index film layer, the second low refractive index film layer, and the third high refractive index film layer are sequentially laminated in a direction from the base material to the optical adjustment film layer;

the first low-refractive-index film layer and the second low-refractive-index film layer are made of aluminum oxide, the thickness of the first low-refractive-index film layer is larger than or equal to 70 nanometers and smaller than or equal to 75 nanometers, and the thickness of the second low-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers;

the first high-refractive-index film layer, the second high-refractive-index film layer and the third high-refractive-index film layer are made of titanium oxide, the thickness of the first high-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers, the thickness of the second high-refractive-index film layer is larger than or equal to 75 nanometers and smaller than or equal to 80 nanometers, and the thickness of the third high-refractive-index film layer is larger than or equal to 65 nanometers and smaller than or equal to 70 nanometers.

11. The composite structural member of any one of claims 6 to 9, wherein the material of the color layer is zirconium nitride, the low refractive index film layer comprises a first low refractive index film layer, the high refractive index film layer comprises a first high refractive index film layer and a second high refractive index film layer, and the first high refractive index film layer, the first low refractive index film layer, and the second high refractive index film layer are sequentially laminated in a direction from the substrate to the optical adjustment film layer;

the material of the first low refractive index film layer is alumina, and the thickness of the first low refractive index film layer is more than or equal to 100 nanometers and less than or equal to 120 nanometers;

the first high-refractive-index film layer and the second high-refractive-index film layer are both made of chromium oxide, the thickness of the first high-refractive-index film layer is larger than or equal to 55 nanometers and smaller than or equal to 60 nanometers, and the thickness of the second high-refractive-index film layer is larger than or equal to 75 nanometers and smaller than or equal to 80 nanometers.

12. The composite structural member of any one of claims 6 to 11, further comprising:

a primer layer disposed between the color layer and the first surface of the substrate;

The material of the priming layer comprises at least one of aluminum, chromium, titanium, silicon and silicon oxide.

13. The composite structural member of claim 12 wherein the primer layer has a thickness greater than or equal to 50 nanometers and less than or equal to 500 nanometers.

14. The composite structural member of any one of claims 1 to 13, further comprising:

the fingerprint prevention layer is arranged on one side surface of the optical adjustment film layer, which is away from the base material.

15. A composite structural member according to any one of claims 1 to 14 wherein the material of the substrate is metal, glass, ceramic or plastic.

16. A method of processing a composite structural member, comprising:

providing a substrate comprising a first surface;

an optical adjustment film layer is formed on one side, facing the first surface, of the base material, and the first appearance surface of the composite structural member is made to be in a preset color, the corresponding L value, a value and b value of the preset color in a Lab color space are respectively L0, a0 and b0, L0 is greater than or equal to 85 and less than or equal to 90, a0 is greater than or equal to 2 and less than or equal to 5, b0 is greater than or equal to 22 and less than or equal to 30, and the Vickers hardness of the optical adjustment layer is greater than or equal to 800, wherein the orientation of the first appearance surface is the same as the orientation of the first surface.

17. The method of claim 16, further comprising, prior to forming the optical modifying film layer on the side of the substrate facing the first surface:

forming a color layer on one side of the first surface of the substrate, wherein the color of the color layer is a first color, and the corresponding L value, a value and b value of the first color in a Lab color space are respectively L1, a1 and b1, deltaL is less than or equal to 20, deltaa is less than or equal to 5 and Deltab is less than or equal to 15;

wherein Δl= |l1-l0|, Δa= |a1-a0|, Δb= |b1-b0|.

18. The method of claim 16 or 17, wherein forming the optical adjustment film layer on the side of the substrate toward which the first surface faces comprises:

and forming the optical adjustment film layer on the side, facing the first surface, of the substrate by adopting an atomic layer deposition process.

19. An electronic device comprising the composite structure of any one of claims 1-15, and/or comprising a composite structure made by the method of processing a composite structure of any one of claims 16-18, the first exterior surface of the composite structure forming at least part of an exterior surface of the electronic device.

20. The electronic device of claim 19, comprising a display module and a housing, the display module disposed in the housing, the housing comprising the composite structural member.