CN110484862B

CN110484862B - Composite coating Logo, preparation method thereof, ceramic cover plate comprising composite coating Logo and electronic equipment comprising composite coating Logo

Info

Publication number: CN110484862B
Application number: CN201810465057.7A
Authority: CN
Inventors: 周群飞; 饶桥兵; 湛玉龙
Original assignee: Lens Technology Changsha Co Ltd
Current assignee: Lens Technology Changsha Co Ltd
Priority date: 2018-05-15
Filing date: 2018-05-15
Publication date: 2022-04-12
Anticipated expiration: 2038-05-15
Also published as: CN110484862A

Abstract

The invention provides a Logo of a composite coating, a preparation method of the Logo, a ceramic cover plate comprising the Logo and electronic equipment, and relates to the technical field of ceramic panels. The composite coating Logo comprises a chromium metal layer used for being in contact with a ceramic substrate and an optical layer arranged on the surface of the chromium metal layer, wherein the optical layer is a combination of a silicon oxide layer and a silicon nitride layer.

Description

Composite coating Logo, preparation method thereof, ceramic cover plate comprising composite coating Logo and electronic equipment comprising composite coating Logo

Technical Field

The invention relates to the technical field of ceramic panels, in particular to a Logo of a composite coating, a preparation method of the Logo, a ceramic cover plate comprising the Logo and electronic equipment comprising the Logo.

Background

With the popularization of intelligent electronic products such as mobile phones, computers, televisions and the like, the appearance requirements of consumers on the electronic products are higher and higher. Taking a mobile phone as an example, the back cover of a mobile phone made of a non-metal material has become one of the design directions pursued by the high-end models of most electronic product manufacturers, and in the coming years, the back cover of a smart phone will gradually change from a metal material to a non-metal material represented mainly by ceramics, glass and jewels.

Because the ceramic is made of opaque materials, unlike glass, the Logo with different colors can be silk-screened on the back of a product, and then the personalized requirements of customers on the Logo can be met by displaying different colors on the front, so that most of the Logo on the existing ceramic cover plate is single metal patterns such as black or white, and the Logo without personalized colorful patterns.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

A first object of the present invention is to provide a composite coating Logo to alleviate the technical problem of the prior art of lacking a color Logo that can be combined with a ceramic matrix.

The second purpose of the invention is to provide a preparation method of a Logo of a composite coating, by which the Logo which is silvery when observed from the front and is blue-green when observed from the side can be prepared on the surface of a ceramic substrate.

The third purpose of the present invention is to provide a ceramic cover plate, and the fourth purpose of the present invention is to provide an electronic device to meet the requirements of different customers on Logo color personalization.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

a composite coating Logo comprises a chromium metal layer used for being in contact with a ceramic substrate and an optical layer arranged on the surface of the chromium metal layer, wherein the optical layer is a combination of a silicon oxide layer and a silicon nitride layer.

Furthermore, a transition layer for increasing the bonding force between the chromium metal layer and the optical layer is arranged between the chromium metal layer and the optical layer;

preferably, the transition layer is a chromium metal compound;

preferably, the chromium metal compound is chromium nitride;

preferably, the thickness of the transition layer is 0.1-200nm, preferably 10-200 nm.

Further, the optical layers comprise a first optical layer and a second optical layer, the first optical layer comprises silicon oxide layers and silicon nitride layers which are alternately arranged, the second optical layer is a silicon oxide layer, and the silicon oxide layer in the first optical layer is in contact with the chromium metal layer or the transition layer;

preferably, the number of layers of the silicon oxide layer and the silicon nitride layer in the first optical layer is 1-4 respectively, and the number of layers of the silicon oxide layer and the silicon nitride layer is the same;

preferably, the thickness of the single silicon oxide layer in the first optical layer is 70-90 nm, preferably 75-85 nm, and the thickness of the single silicon nitride layer is 50-100 nm, preferably 60-90 nm;

preferably, the thickness of the silicon oxide layer in the second optical layer is 60-85 nm, and preferably 65-80 nm.

Furthermore, the thickness of the chromium metal layer is 30-70 nm, preferably 40-60 nm.

A preparation method of the composite coating Logo comprises the steps of providing a ceramic substrate, and sequentially forming (a) a chromium metal layer, (b) an optional transition layer and (c) an optical layer on the surface of the ceramic substrate to obtain the composite coating Logo.

Further, preparing a chromium metal layer and an optional transition layer on the surface of the ceramic substrate by adopting a magnetron sputtering method, and preparing an optical layer on the surface of the chromium metal layer or the transition layer by adopting the magnetron sputtering method to obtain the composite coating Logo.

Further, a chromium target is selected and a magnetron sputtering method is utilized to deposit a chromium metal layer on the surface of the ceramic substrate, and the magnetron sputtering technological parameters of the chromium metal layer comprise: the power of the chromium target is 6000-7000W, the flow of argon is 80-120 sccm, and the deposition rate is 0.03-0.3 nm/s;

preferably, a chromium target is selected and a chromium nitride transition layer is deposited on the surface of the chromium metal layer by using a magnetron sputtering method, and the magnetron sputtering technological parameters of the chromium nitride transition layer comprise: the power of the chromium target is 6000-7000W, the RF power is 1500-3000W, the flow of argon is 0-150 sccm, the flow of nitrogen is 40-80 sccm, and the deposition rate is 0.1-0.4 nm/s;

preferably, a silicon target is selected and a magnetron sputtering method is utilized to alternately deposit a silicon oxide layer and a silicon nitride layer on the surface of the chromium metal layer or the transition layer;

the magnetron sputtering technological parameters of the silicon oxide layer comprise: the silicon target power is 6000-8000W, the RF power is 1000-3000W, the argon flow is 0-150 sccm, the oxygen flow is 120-150 sccm, and the deposition rate is 0.2-0.4 nm/s;

the magnetron sputtering technological parameters of the silicon nitride layer comprise: the silicon target power is 6000-8000W, the RF power is 1000-3000W, the argon flow is 0-150 sccm, the nitrogen flow is 30-80 sccm, and the deposition rate is 0.2-0.4 nm/s.

Further, forming a Logo hollow pattern on the surface of the ceramic substrate by using a protective film or printing ink, and preparing the Logo of the composite coating by using the magnetron sputtering method;

preferably, after the ceramic substrate with the hollowed-out pattern formed on the surface is subjected to plasma surface treatment, the composite coating Logo is prepared by the magnetron sputtering method;

preferably, the process parameters of the plasma surface treatment include: background vacuum degree of 3.0-4.0 x 10^-4Pa, RF power of 2000-3000W, argon gas flow of 80-300 sccm, oxygen flow of 80-300 sccm, and processing time of 180-1200 s.

The ceramic cover plate comprises a ceramic substrate and the composite coating Logo arranged on the surface of the ceramic substrate or the composite coating Logo obtained by the preparation method.

An electronic device comprises the ceramic cover plate.

Compared with the prior art, the invention has the following beneficial effects:

the composite coating Logo provided by the invention comprises a chromium metal layer and an optical layer, wherein the chromium metal layer is used for being in contact with a ceramic substrate, and the metallic chromium shows silver color, so that the composite coating Logo shows silver color when seen from the front; meanwhile, the optical layer composed of the silicon oxide layer and the silicon nitride layer covers the surface of the chromium metal layer, and when the Logo of the composite coating is observed on different sides, different colors can be displayed due to the projection, refraction and reflection of light. By changing the combination sequence and thickness of the silicon oxide layer and the silicon nitride layer in the optical layer, various colors from blue-green to green can be obtained.

In addition, the binding force between the chromium metal and the ceramic matrix is higher, so the Logo provided by the invention has higher adhesion force with the ceramic matrix; meanwhile, the combination of the silicon oxide layer and the silicon nitride layer is selected as the optical layer, so that the scratch resistance of the Logo can be improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a composite coating Logo provided in example 1 of the present invention;

FIG. 2 is a schematic top view of a ceramic cover plate according to example 2 of the present invention;

FIG. 3 is a schematic cross-sectional view of a ceramic cover plate according to example 2 of the present invention;

FIG. 4 is a schematic structural diagram of a composite coating Logo provided in example 3 of the present invention;

fig. 5 is a schematic cross-sectional view of a ceramic cover plate in example 4 of the present invention.

Icon: 10-a ceramic substrate; 20-Logo; 21-a chromium metal layer; 22-a silicon oxide layer; 23-a silicon nitride layer; a 24-chromium nitride transition layer.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

One aspect of the invention provides a composite coating Logo, which comprises a chromium metal layer used for contacting with a ceramic substrate and an optical layer arranged on the surface of the chromium metal layer, wherein the optical layer is a combination of a silicon oxide layer and a silicon nitride layer.

It should be noted that the chromium metal layer in the present invention is used to display a metallic color, and the optical layer composed of the silicon oxide layer and the silicon nitride layer is used to transmit, reflect and refract a light source. When the thickness of the optical layer is nano-scale, the color of the chromium metal layer can be perceived as silver color through the optical layer when viewed from the front; and when viewed from the side, light is transmitted, refracted, and reflected in the optical layer due to the presence of the optical layer so that it can be displayed as different colors from cyan to green.

In the invention, the optical layer only needs to comprise the silicon oxide layer and the silicon nitride layer, the invention does not make specific combination limitation on the silicon oxide layer and the silicon nitride layer in the optical layer, and the obtained Logo can display different colors between blue-green and green by adjusting the combination sequence of the silicon oxide layer and the silicon nitride layer or adjusting the thicknesses of the silicon oxide layer and the silicon nitride layer or simultaneously adjusting the combination sequence and the thicknesses.

For example, the structure of the optical layer includes, but is not limited to: 1) a silicon oxide layer and a silicon nitride layer which are arranged on the surface of the chromium metal layer or the transition layer in sequence; 2) the silicon oxide layer, the silicon nitride layer, the silicon oxide layer and the silicon nitride layer are arranged on the surface of the chromium metal layer or the transition layer in sequence; 3) the silicon oxide layer, the silicon nitride layer, the silicon oxide layer, the silicon nitride layer and the silicon oxide layer are arranged on the surface of the chromium metal layer or the transition layer in sequence; 4) the silicon nitride layer and the silicon oxide layer are sequentially arranged on the surface of the chromium metal layer or the transition layer; 5) the silicon nitride layer, the silicon oxide layer, the silicon nitride layer and the silicon oxide layer are arranged on the surface of the chromium metal layer or the transition layer in sequence; 6) a silicon nitride layer, a silicon oxide layer, a silicon nitride layer and the like which are arranged on the surface of the chromium metal layer or the transition layer in sequence.

In some embodiments of the present invention, a transition layer for increasing the bonding force between the chromium metal layer and the optical layer is disposed between the chromium metal layer and the optical layer. The transition layer can be selectively arranged between the chromium metal layer and the optical layer, so that the adhesive force between the chromium metal layer and the optical layer can be improved.

The composite coating Logo in the invention can be a combination of a chromium metal layer and an optical layer, and can also be a combination of a chromium metal layer, a transition layer and an optical layer which are arranged in sequence.

In some embodiments of the invention, the transition layer is a chromium metal compound. Optionally, the chromium metal compound is chromium nitride. Chromium nitride is selected as the transition layer, so that the bonding force between the chromium metal layer and the optical layer is improved, and the effect of reducing the brightness of the chromium metal layer can be achieved, so that the color of the chromium metal layer is softer.

In some embodiments of the invention, the transition layer has a thickness of 0.1 to 200nm, preferably 10 to 200 nm.

In the above embodiment, the thickness of the transition layer may be, for example: 0.1nm, 10nm, 50nm, 100nm, 150nm or 200 nm.

In some embodiments of the present invention, the optical layer comprises a first optical layer and a second optical layer, the first optical layer comprises silicon oxide layers and silicon nitride layers which are alternately arranged, the second optical layer is a silicon oxide layer, and the silicon oxide layer in the first optical layer is in contact with the chromium metal layer or the transition layer; optionally, the number of the silicon oxide layers and the number of the silicon nitride layers in the first optical layer are respectively 1-4, and the number of the silicon oxide layers is the same as that of the silicon nitride layers. The Logo showing a blue-green color when viewed from the side can be obtained by the optical layer having the above structure.

In the above embodiment, the thickness of the single silicon oxide layer in the first optical layer is 70 to 90nm, preferably 75 to 85nm, and the thickness of the silicon nitride layer is 50 to 100nm, preferably 60 to 90 nm; optionally, the thickness of the silicon oxide layer in the second optical layer is 60-85 nm, preferably 65-80 nm; optionally, the thickness of the chromium metal layer is 30-70 nm, preferably 40-60 nm.

In a second aspect of the present invention, a method for preparing a composite coating Logo is provided, wherein a ceramic substrate is provided, and (a) a chromium metal layer, (b) an optional transition layer, and (c) an optical layer are sequentially formed on the surface of the ceramic substrate to obtain the composite coating Logo.

The Logo obtained by the preparation method provided by the invention has all the advantages of the Logo of the composite coating, and is not described again.

In some embodiments of the present invention, a magnetron sputtering method is used to prepare a chromium metal layer and optionally a transition layer on a surface of a ceramic substrate, and then a magnetron sputtering method is used to prepare an optical layer on the surface of the chromium metal layer or the transition layer, so as to obtain the Logo of the composite coating. The chromium metal layer, the optical layer and the optional transition layer are prepared by a magnetron sputtering method, so that the bonding strength among the layers can be improved, and the scratch resistance of the Logo is further improved.

In some embodiments of the present invention, a chromium target is selected and used to deposit a chromium metal layer on the surface of the ceramic substrate by using a magnetron sputtering method, and the magnetron sputtering process parameters of the chromium metal layer include: the power of the chromium target is 6000-7000W, the flow of argon is 80-120 sccm, and the deposition rate is 0.03-0.3 nm/s;

optionally, a chromium target is selected and a magnetron sputtering method is used for depositing a chromium nitride transition layer on the surface of the chromium metal layer, and the magnetron sputtering technological parameters of the chromium nitride transition layer include: the power of the chromium target is 6000-7000W, the RF power is 1500-3000W, the flow of argon is 0-150 sccm, the flow of nitrogen is 40-80 sccm, and the deposition rate is 0.1-0.4 nm/s.

In some embodiments of the invention, a silicon target is selected and used for alternately depositing a silicon oxide layer and a silicon nitride layer on the surface of the chromium metal layer or the transition layer by using a magnetron sputtering method;

In some embodiments of the present invention, a Logo hollowed-out pattern is formed on the surface of the ceramic substrate by using a protective film or ink, and then the composite coating Logo is prepared by using the magnetron sputtering method.

The method comprises the steps of firstly carrying out ultrasonic cleaning on a ceramic substrate before a protective film or screen printing ink is pasted to remove dirt on the surface of the ceramic substrate, then obtaining a Logo pattern on the surface of the ceramic substrate by using the protective film or the printing ink, and then carrying out preheating and drying treatment and then preparing the Logo by using a magnetron sputtering method. For example, a magnetron sputtering coater can be used for preheating and drying treatment, and the preheating and drying treatment conditions are as follows: vacuum degree of 8X 10^-3Pa, the baking temperature of the tungsten lamp is 90-100 ℃, and the drying time is 12-18 min.

In some embodiments of the invention, the ceramic substrate with the hollow pattern formed on the surface is subjected to plasma surface treatment, and then the magnetron sputtering method is utilized to prepare the composite coating Logo are provided. Optionally, the process parameters of the plasma surface treatment include: background vacuum degree of 3.0-4.0 x 10^-4Pa, RF power of 2000-3000W, argon gas flow of 80-300 sccm, oxygen flow of 80-300 sccm, and processing time of 180-1200 s.

The ceramic matrix with the Logo pattern is treated by adopting a plasma surface treatment process, so that defects and impurities on the surface of the ceramic matrix can be removed, and the binding force between the ceramic matrix and the chromium metal layer is further improved.

The third aspect of the invention provides a ceramic cover plate, which comprises a ceramic substrate and a composite coating Logo arranged on the surface of the ceramic substrate or the composite coating Logo obtained by the preparation method.

A fourth aspect of the present invention provides an electronic device comprising the above ceramic cover plate.

The present invention will be described in further detail with reference to examples.

Example 1

As shown in fig. 1, the embodiment is a composite coating Logo, which includes a chromium metal layer 21 for bonding with a ceramic substrate and an optical layer attached to the chromium metal layer 21, wherein the optical layer includes a silicon oxide layer 22, a silicon nitride layer 23, and a silicon oxide layer 22. The thickness values for the specific layers are listed in table 1.

Table 1 Logo film thickness table for composite coating in example 1

In the embodiment, the composite coating Logo having the above structure shows a silver color when viewed from the front and a cyan color when viewed from the side.

Example 2

As shown in fig. 2 and 3, the present embodiment is a ceramic cover plate, including a ceramic substrate 10 and a Logo 20 provided in embodiment 1 and disposed on the ceramic substrate 10, and the method for manufacturing the ceramic cover plate in the present embodiment includes the following steps:

step a): preparing a high-gloss polished ceramic product, and cleaning by adopting a full-automatic twelve-groove ultrasonic cleaning machine;

step b): making a hollowed Logo pattern according to the requirement of dimensional tolerance by screen printing ink, and then detecting whether the requirement of a signal tolerance test is met;

step c): placing the ceramic substrate with the manufactured hollowed Logo pattern into a transition chamber of a magnetron sputtering coating machine for preheating and drying, wherein the process parameters of the process are as follows: vacuum-pumping to 8.0 × 10^-3Pa, simultaneously baking and heating for 15min by using a tungsten lamp in the cavity, wherein the baking temperature is 90 ℃;

step d): after preheating and drying, the ceramic substrate is conveyed into a coating cavity of a magnetron sputtering coating machine, the ceramic substrate is subjected to plasma cleaning and then coated, and the background vacuum degree in the coating cavity in the plasma cleaning and coating processes is 4.0 multiplied by 10^-4Pa; the plasma cleaning process parameters are listed in table 2, and the coating process parameters of each layer of film are listed in table 3;

TABLE 2 plasma cleaning Process parameters

RF power (w)	Ar/sccm	O₂/sccm	Time/s
				3000	120	100	300

TABLE 3 coating process parameters for each layer of film

Step e): and (4) carrying out deplating ink treatment on the ceramic substrate subjected to film coating, and cleaning by using a full-automatic twelve-groove ultrasonic cleaner to obtain the ceramic cover plate.

Example 3

As shown in fig. 4, the composite coating Logo includes a chromium metal layer 21 for bonding with a ceramic substrate, a chromium nitride transition layer 24 and an optical layer are sequentially disposed on the surface of the chromium metal layer 21, and the optical layer includes a silicon oxide layer 22, a silicon nitride layer 23, a silicon oxide layer 22, a silicon nitride layer 23 and a silicon oxide layer 22. The thickness values for the specific layers are given in Table 4.

Table 4 Logo film thickness table of composite coating in example 3

In the embodiment, the composite coating Logo having the above structure shows a silver color when viewed from the front and a cyan color when viewed from the side. The lightness when silver is displayed is lower than Logo in example 1.

Example 4

As shown in fig. 5, the present embodiment is a ceramic cover plate, including a ceramic substrate 10 and a Logo 20 provided in embodiment 3, where the method for manufacturing the ceramic cover plate in the present embodiment includes the following steps:

step c): placing the ceramic substrate with the manufactured hollowed Logo pattern into a transition chamber of a magnetron sputtering coating machine for preheating and drying, wherein the process parameters of the process are as follows: is vacuumized to8.0×10^-3Pa, simultaneously baking and heating for 15min by using a tungsten lamp in the cavity, wherein the baking temperature is 90 ℃;

step d): after preheating and drying, the ceramic substrate is conveyed into a coating cavity of a magnetron sputtering coating machine, the ceramic substrate is subjected to plasma cleaning and then coated, and the background vacuum degree in the coating cavity in the plasma cleaning and coating processes is 4.0 multiplied by 10^-4Pa; the plasma cleaning process parameters are listed in table 5, and the coating process parameters of each layer of film are listed in table 6;

TABLE 5 plasma cleaning Process parameters

RF power (w)	Ar/sccm	O₂/sccm	Time/s
				3000	120	100	300

TABLE 6 coating parameters for each layer of film

The Logo in the ceramic cover plates provided in examples 2 and 4 was subjected to a performance test, the chroma of the Logo was measured with a colorimeter, and then the pencil hardness, the water boiling performance, the thermal cyclicity, and the thermal shock of the Logo were measured, and the test structures are listed in table 7.

TABLE 7 test results

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite coating Logo is characterized by comprising a chromium metal layer used for being in contact with a ceramic substrate and an optical layer arranged on the surface of the chromium metal layer, wherein the optical layer is a combination of a silicon oxide layer and a silicon nitride layer;

a transition layer used for increasing the bonding force between the chromium metal layer and the optical layer is arranged between the chromium metal layer and the optical layer;

the transition layer is a chromium metal compound;

the chromium metal compound is chromium nitride;

the optical layer comprises a first optical layer and a second optical layer, the first optical layer comprises silicon oxide layers and silicon nitride layers which are alternately arranged, the second optical layer is a silicon oxide layer, and the silicon oxide layer in the first optical layer is in contact with the chromium metal layer or the transition layer.

2. The composite coating Logo according to claim 1, wherein the thickness of the transition layer is 0.1-200 nm.

3. The composite coating Logo according to claim 1, wherein the thickness of the transition layer is 10-200 nm.

4. The Logo with the composite coating according to claim 1, wherein the number of the silicon oxide layers and the silicon nitride layers in the first optical layer is 1-4, and the number of the silicon oxide layers and the silicon nitride layers is the same.

5. The Logo according to claim 4, wherein the thickness of the single silicon oxide layer in the first optical layer is 70-90 nm and the thickness of the single silicon nitride layer is 50-100 nm.

6. The Logo according to claim 5, wherein the thickness of the single silicon oxide layer in the first optical layer is 75-85 nm, and the thickness of the single silicon nitride layer is 60-90 nm.

7. The composite coating Logo according to claim 1, wherein the thickness of the silicon oxide layer in the second optical layer is 60-85 nm.

8. The composite coating Logo according to claim 7, wherein the thickness of the silicon oxide layer in the second optical layer is 65-80 nm.

9. The composite coating Logo according to any one of claims 1 to 3, wherein the thickness of the chromium metal layer is 30 to 70 nm.

10. The composite coating Logo according to claim 9, wherein the thickness of the chromium metal layer is 40-60 nm.

11. A method for producing a composite coating Logo according to any one of claims 1 to 10, wherein a ceramic substrate is provided, on the surface of which (a) a chromium metal layer, (b) optionally a transition layer, and (c) an optical layer are formed in this order, to obtain said composite coating Logo.

12. The preparation method according to claim 11, characterized in that a magnetron sputtering method is adopted to prepare the chromium metal layer and optionally the transition layer on the surface of the ceramic substrate, and then a magnetron sputtering method is adopted to prepare the optical layer on the surface of the chromium metal layer or the transition layer, so as to obtain the Logo of the composite coating.

13. The preparation method of claim 12, wherein a chromium target is selected and used for depositing the chromium metal layer on the surface of the ceramic substrate by a magnetron sputtering method, and the magnetron sputtering process parameters of the chromium metal layer comprise: the power of the chromium target is 6000-7000W, the flow of argon gas is 80-120 sccm, and the deposition rate is 0.03-0.3 nm/s.

14. The preparation method of claim 13, wherein a chromium target is selected and a chromium nitride transition layer is deposited on the surface of the chromium metal layer by a magnetron sputtering method, and the magnetron sputtering process parameters of the chromium nitride transition layer comprise: the power of the chromium target is 6000-7000W, the RF power is 1500-3000W, the flow of argon is 0-150 sccm, the flow of nitrogen is 40-80 sccm, and the deposition rate is 0.1-0.4 nm/s.

15. The preparation method according to claim 12, wherein a silicon target is selected and used for alternately depositing a silicon oxide layer and a silicon nitride layer on the surface of the chromium metal layer or the transition layer by a magnetron sputtering method;

16. The preparation method according to any one of claims 11 to 15, characterized in that a Logo hollowed-out pattern is formed on the surface of the ceramic substrate by using a protective film or ink, and then the composite coating Logo is prepared by using the magnetron sputtering method.

17. The preparation method of claim 16, wherein the ceramic substrate with the hollow pattern formed on the surface is subjected to plasma surface treatment, and then the magnetron sputtering method is used for preparing the composite coating Logo.

18. The method of claim 17, wherein the process parameters of the plasma surface treatment include: background vacuum degree of 3.0-4.0 x 10^-4Pa, RF power of 2000-3000W, argon gas flow of 80-300 sccm, oxygen flow of 80-300 sccm, and processing time of 180-1200 s.

19. A ceramic cover plate comprising a ceramic substrate and the composite coating Logo according to any one of claims 1 to 10 or obtained by the production method according to any one of claims 11 to 18 provided on the surface of the ceramic substrate.

20. An electronic device comprising the ceramic cover of claim 19.