Method for forming two-color coating

Abstract

A method for forming a two-color coating sequentially comprises the steps that (a) a coating with a first color is formed on the step surface of a workpiece, and the step surface is provided with a lower section, an upper section and a middle section connecting the lower section and the upper section; (b) forming an ink layer with a second color on the coating at the step surface; (c) softly baking the ink layer; (d) exposing a first region of the ink layer corresponding to the lower section and the intermediate section to cause a cross-linking reaction thereof; (e) developing the ink layer to remove a second region of the ink layer and expose the coating corresponding to the upper section, wherein the second region is not cross-linked and corresponds to the upper section; and (f) hard baking the ink layer so as to exhibit the second color at the lower and middle sections of the workpiece and the first color at the upper section thereof. The ink layer with the second color can completely cover the coatings at the lower interval and the middle interval of the step surface so as to solve the offset problem caused by the step surface, and the method can be implemented only by low-step lithography equipment, so that the equipment cost is also saved.

Description

Technical Field

[0001] The present invention relates to a method for forming a coating, in particular to a method for forming a two-color coating. Background Art

[0002] With the advancement of the technology industry, demand for 3C products, such as computers and computer peripherals, communications, and consumer electronics, is increasing. As consumers' expectations for the appearance of 3C products gradually increase, the design of 3C products is gaining increasing attention in the industry. Therefore, within the 3C product-related technology industry, the aesthetics of the casings / housings and keyboards of 3C products, such as mobile phones, laptops, and tablet computers, are receiving particular attention.

[0003] Taking the appearance of a laptop computer's keyboard housing (not shown) as an example, the keyboard housing is generally divided into a keyboard area and a non-keyboard area. The keyboard area of ​​the keyboard housing refers to the area configured with multiple through-holes for each corresponding keyboard key, while the non-keyboard area of ​​the keyboard housing generally refers to the area around the keyboard area that extends away from the through-holes and is used to accommodate a touchpad or for contact with a user's wrist. It is well known that when the laptop computer's screen is not unfolded, it is positioned facing the keyboard housing to present the laptop in a folded state. To prevent the keyboard keys protruding from the through-holes toward the screen from interfering with the folding of the screen when the laptop computer is in the folded state, the industry typically creates a height difference between the keyboard area and the non-keyboard area when designing the keyboard housing. In other words, the keyboard housing has a stepped surface with a lower section, an upper section, and an intermediate section connecting the lower and upper sections.

[0004] To meet the consumer demand for laptop computer appearance, laptop computer manufacturers often color the keyboard housing, making the keyboard area and non-keyboard area of ​​the keyboard housing appear in different colors, thereby highlighting the beauty of the keyboard housing. There are two existing coloring methods.

[0005] The first coloring method involves covering the keyboard or non-keyboard area of ​​the keyboard housing with a masking spray jig, then spraying the uncovered areas with paint. While this method creates a two-color keyboard housing for a beautiful effect, it also creates a discontinuity due to the stepped surface (i.e., the center section remains unpainted), which detracts from its aesthetic appeal.

[0006] The second coloring method combines a charge coupled device (CCD), software, and inkjet printing equipment to align the keyboard housing, switch paint colors, and print, creating a seamless, aesthetically pleasing stepped surface. While this second coloring method addresses the issues left by the first, its equipment costs are relatively higher than the first.

[0007] As can be seen from the above description, improving the method for forming a two-color coating to solve the problem of step difference caused by the stepped surface while saving equipment costs is a problem to be solved by relevant industries in the relevant technical field. Summary of the Invention

[0008] The object of the present invention is to provide a method for forming a two-color coating which can solve the problem of step difference caused by a stepped surface and save equipment costs.

[0009] The method for forming a two-color coating of the present invention comprises the following steps: step (a), step (b), step (c), step (d), step (e), and step (f).

[0010] The step (a) is to apply a first coating process to a workpiece having a stepped surface, so that a coating having a first color is formed on the stepped surface of the workpiece, wherein the stepped surface has a lower section, an upper section located higher than the lower section, and an intermediate section connecting the lower section and the upper section.

[0011] The step (b) is to form an ink layer having a second color on the coating layer corresponding to the step surface after the step (a).

[0012] The step (c) is to soft bake the ink layer after the step (b).

[0013] The step (d) is to expose the first region of the ink layer after the step (c) to generate a crosslinking reaction, wherein the first region of the ink layer corresponds to the lower section and the middle section of the step surface.

[0014] The step (e) is to develop the ink layer after the step (d) to remove the second region of the ink layer, thereby exposing the coating layer at the upper section corresponding to the step surface, wherein the second region of the ink layer has not undergone a cross-linking reaction and corresponds to the upper section of the step surface.

[0015] The step (f) is to hard bake the ink layer after the step (e), so that the second color appears in the lower and middle sections of the stepped surface of the workpiece, and the first color appears in the upper section of the stepped surface of the workpiece.

[0016] In the method for forming a two-color coating of the present invention, in step (a), the workpiece is made of aluminum alloy, magnesium alloy, stainless steel, titanium or plastic.

[0017] In the method for forming a two-color coating of the present invention, in step (a), the first coating process is anodizing, electroplating, electrophoretic coating, physical vapor deposition (PVD), or spray painting.

[0018] In the method for forming a two-color coating of the present invention, in step (b), the ink layer has a thickness between 5 μm and 8 μm.

[0019] In the method for forming a two-color coating of the present invention, in step (c), the soft baking temperature is between 90° C. and 120° C., and the soft baking time is between 5 minutes and 15 minutes.

[0020] In the method for forming a two-color coating of the present invention, in step (e), a weak alkaline developer is used to develop the second area of ​​the ink layer.

[0021] In the method for forming the two-color coating of the present invention, in step (f), the hard baking temperature is between 140° C. and 160° C., and the hard baking time is not less than 1 hour.

[0022] The beneficial effect of the present invention is that the ink layer having the second color is formed on the coating corresponding to the stepped surface, which can completely cover the coating in the lower section and the middle section of the stepped surface to solve the step difference problem caused by the stepped surface, and only low-level lithography equipment is required to implement it, which also saves equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0024] Figure 1 is a schematic diagram illustrating step (a) of an embodiment of a method for forming a two-color coating according to the present invention;

[0025] Figure 2is a schematic diagram illustrating step (b) of the forming method of the embodiment of the present invention;

[0026] Figure 3 is a schematic diagram illustrating step (c) of the forming method of the embodiment of the present invention;

[0027] Figure 4 is a schematic diagram illustrating step (d) of the forming method according to the embodiment of the present invention;

[0028] Figure 5 is a schematic diagram illustrating step (e) of the forming method according to an embodiment of the present invention; and

[0029] Figure 6 FIG. 1 is a schematic diagram illustrating step (f) of the forming method according to the embodiment of the present invention. DETAILED DESCRIPTION

[0030] Before the present invention is described in detail, it should be noted that similar components are denoted by the same reference numerals in the following description.

[0031] An embodiment of the method for forming a two-color coating of the present invention is applicable to a keyboard housing of a laptop computer (i.e., a workpiece 2), which includes the following steps: a step (a), a step (b), a step (c), a step (d), a step (e), and a step (f).

[0032] See Figure 1 The step (a) is to apply a first coating process to the workpiece 2 having a stepped surface 21, so that a coating 3 having a first color is formed on the stepped surface 21 of the workpiece 2. Figure 1 As shown, the stepped surface 21 has a lower section 211, an upper section 212 positioned higher than the lower section 211, and an intermediate section 213 connecting the lower section 211 and the upper section 212. Preferably, in step (a), the workpiece 2 is made of aluminum alloy, magnesium alloy, stainless steel, titanium or plastic, and the first coating process is anodized, electroplated, electrophoretically coated, physical vapor deposition (PVD) or spray painted. In the embodiment of the present invention, the workpiece 2 of step (a) is made of aluminum alloy, and the first coating process is anodized, so that the coating 3 formed after step (a) is an aluminum oxide layer having the first color and a thickness between 8μm and 15μm. The embodiment of the present invention is only described by taking the example of the workpiece 2 being made of aluminum alloy and anodized, but is not limited thereto.

[0033] See Figure 2 The step (b) is to form an ink layer 4 having a second color on the coating layer 3 corresponding to the step surface 21 after the step (a).

[0034] See Figure 3 Step (c) involves soft baking the ink layer 4 after step (b). Specifically, in step (c), the workpiece 2, having the coating layer 3 and ink layer 4 formed thereon, is placed in an oven 5 for soft baking. Preferably, in step (c), the soft baking temperature is between 90°C and 120°C, and the soft baking time is between 5 and 15 minutes.

[0035] See Figure 4 Step (d) involves exposing a first region 41 of the ink layer 4 after step (c) to cause a crosslinking reaction. The first region 41 of the ink layer 4 corresponds to the lower region 211 and the middle region 213 of the stepped surface 21. Specifically, step (d) involves placing a photomask 6 above the workpiece 2 on which the coating layer 3 and the ink layer 4 are formed, exposing the first region 41 of the ink layer 4. A UV light source 7 above the photomask 6 is then used to expose the first region 41 exposed outside the photomask 6, causing the first region 41 of the ink layer 4 to undergo a crosslinking reaction, thereby preventing the ink layer 4 in the first region 41 from being removed during step (e).

[0036] See Figure 5 The step (e) is to develop the ink layer 4 after the step (d) to remove the ink layer 4. Figure 4 The second region 42 shown in FIG. 4 is exposed, thereby revealing the coating layer 3 at the upper section 212 corresponding to the step surface 21. The second region 42 of the ink layer 4 is not cross-linked and corresponds to the upper section 212 of the step surface 21. It should be noted that, in order to prevent the first color of the coating layer 3 at the upper section 212 corresponding to the step surface 21 from being damaged by development, it is preferred that, in step (e), a weak alkaline developer 8 is used to develop the second region 42 of the ink layer 4. Specifically, step (e) is as follows: Figure 5 As shown, the ink layer 4 after the step (d) is immersed in the weak alkaline developer 8, so that the ink layer 4 corresponding to the upper interval 212 of the step surface 21 and not subjected to the cross-linking reaction is dissolved in the weak alkaline developer 8, thereby removing the ink layer 4 corresponding to the upper interval 212 of the step surface 21 and not subjected to the cross-linking reaction.

[0037] See Figure 6 Step (f) involves hard baking the ink layer 4 after step (e), thereby presenting the second color of the ink layer 4 in the lower region 211 and the middle region 213 of the stepped surface 21 of the workpiece 2, and presenting the first color of the coating 3 in the upper region 212 of the stepped surface 21 of the workpiece 2. Specifically, in step (f), the workpiece 2, after removing the uncrosslinked ink layer 4 corresponding to the upper region 212 of the stepped surface 21, is placed in the oven 5 for hard baking. Preferably, in step (f), the hard baking temperature is between 140°C and 160°C, and the hard baking time is no less than 1 hour.

[0038] It should be noted that, given that the method for forming the two-color coating according to the embodiment of the present invention requires removing the second region 42 of the ink layer 4 (i.e., corresponding to the upper region 212 of the stepped surface 21), the first color of the coating layer 3 and the second color of the ink layer 4 are revealed. To avoid a significant height difference between the first color of the coating layer 3 and the second color of the ink layer 4, which would impair the visual effect after implementing the embodiment of the present invention, it is preferred that, in step (b) of the embodiment of the present invention, the ink layer 4 has a thickness between 5 μm and 8 μm, which is difficult to discern with the naked eye.

[0039] As can be seen from the detailed description of the method for forming a two-color coating according to the embodiment of the present invention, the ink layer 4 having the second color is formed on the coating layer 3 at locations corresponding to the stepped surface 21 (i.e., the lower section 211, the upper section 212, and the middle section 213). Therefore, after implementing the embodiment of the present invention, the ink layer 4 can completely cover the coating layer 3 at the lower section 211 and the middle section 213 of the stepped surface 21, thereby resolving the problem of the step difference caused by the stepped surface 21. Furthermore, the thickness of the ink layer 4 having the second color is very small, and consumers cannot visually discern the height difference between the first color of the coating layer 3 and the second color of the ink layer 4. Furthermore, the embodiment of the present invention only requires low-end lithography equipment to implement, and its equipment cost is relatively lower than the equipment used for the second coloring method described in the prior art.

[0040] In summary, in the method for forming a two-color coating of the present invention, the ink layer 4 having the second color is formed on the coating layer 3 corresponding to the stepped surface 21. It can completely cover the coating layer 3 in the lower section 211 and the middle section 213 of the stepped surface 21 to solve the step difference problem caused by the stepped surface 21. It can be implemented with only low-level lithography equipment, which also saves equipment costs, and thus can indeed achieve the purpose of the present invention.

[0041] However, the above description is only an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A method for forming a two-color coating, characterized in that: The following steps are involved: Step (a), applying a first coating process to a workpiece having a stepped surface, so that a coating having a first color is formed on the stepped surface of the workpiece, wherein the stepped surface has a lower section, an upper section located higher than the lower section, and an intermediate section connecting the lower section and the upper section; Step (b), after step (a), forming an ink layer having a second color on the coating layer corresponding to the stepped surface; Step (c), soft baking the ink layer after step (b); Step (d), exposing the first area of ​​the ink layer after step (c) to cause a cross-linking reaction, wherein the first area of ​​the ink layer corresponds to the lower interval and the middle interval of the step surface; Step (e), developing the ink layer after step (d) to remove the second region of the ink layer, thereby exposing the coating layer at the upper interval corresponding to the step surface, wherein the second region of the ink layer is not cross-linked and corresponds to the upper interval of the step surface; and Step (f), hard baking the ink layer after step (e), so that the second color appears in the lower and middle sections of the stepped surface of the workpiece, and the first color appears in the upper section of the stepped surface of the workpiece.

2. The method for forming a two-color coating according to claim 1, characterized in that: In the step (a), the workpiece is made of aluminum alloy, magnesium alloy, stainless steel, titanium or plastic.

3. The method for forming a two-color coating according to claim 1, characterized in that: In the step (a), the first coating process is anodizing, electroplating, electrophoretic coating, physical vapor deposition or spray painting.

4. The method for forming a two-color coating according to claim 1, characterized in that: In the step (b), the ink layer has a thickness ranging from 5 μm to 8 μm.

5. The method for forming a two-color coating according to claim 1, characterized in that: In the step (c), the soft baking is performed at a temperature between 90° C. and 120° C., and the soft baking time is performed between 5 minutes and 15 minutes.

6. The method for forming a two-color coating according to claim 1, characterized in that: In the step (e), a weak alkaline developer is used to develop the second area of ​​the ink layer.

7. The method for forming a two-color coating according to claim 1, characterized in that: In the step (f), the hard baking is performed at a temperature between 140° C. and 160° C., and the hard baking time is not less than 1 hour.

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