Patent Application
20110174663
1. Technical Field
The present disclosure generally relates to device casings, and particularly, to a casing colored by physical vapor deposition (PVD).
2. Description of Related Art
Colored device casings are often formed by injection of colored plastic or spraying coating on a surface of a casing. However, neither method can provide an attractive metal texture. Furthermore, metal coating technology is complicated and difficult to control, so only a few colors are available for metal casings.
Therefore, it is desirable to provide a casing and a method for fabricating the casing which can overcome the described limitations.
Many aspects of the disclosure can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present colored device casing and method for fabricating the casing. Moreover, in the drawings, like reference numerals designate corresponding parts throughout various views.
Embodiments of the disclosure will now be described in detail with reference to the accompanying drawings.
Referring to
The base 1 can be metal such as steel, or can be ceramic or glass. The base 1 includes at least one surface to be coated, which includes at least one smooth region.
The smooth region is also referred to as a high-gloss or a mirror-like region. It is noted that the base 1 may include many surfaces to be coated, and each surface includes many different surface conditions. For example, the base 1 may include both a high-gloss region and a matte region.
The bonding layer 2 is formed between the base 1 and the color layer 3 for connection therebetween. Thus, the bonding layer 2 can include any material providing proper adhesion, such as chromium nitride (CrN).
The color layer 3 is configured to provide desired color, and includes one or more metal layers. In one embodiment, the color layer 3 includes a layer of an alloy of titanium (Ti).
The coating layer 4 can include any appropriate material for protection, such material providing pollution resistance, electrical insulation, moisture insulation, or mechanical hardness.
The part of the colored device casing 10 including the base 1, the bonding layer 2 and the color layer 3 (i.e. excluding the coating layer 4) may exhibit a Vickers hardness equaling or exceeding 500 HV.
Referring to
Referring also to
Subsequently, a bonding layer 2 is formed on a predetermined surface or region of the base 1. The bonding layer 2 may be formed by PVD, especially PVD sputtering. In one embodiment, argon plasma is excited at a flow rate from 27 to 33 standard cubic centimeters per minute (sccm) by a radio frequency (RF) generator to bombard a chromium target, and nitrogen gas is supplied at a flow rate from 400 to 600 sccm. As a result, chromium vapor is generated and combines with the nitrogen gas, and chromium nitride is obtained and deposits on the base 1.
Thereafter, a color layer 3 is formed on the bonding layer 2. This may include sputtering PVD with argon plasma excited by power supplies to bombard a titanium target. In one embodiment, the power bombarding the titanium target is in a range from 13.5 to 16.5 kilowatts (kW), the process temperature is in a range from 180° C. to 220° C., the process time is in a range from 9 to 11 minutes, and the process pressure is in a range from 5.31 to 6.49 millitorr (mtorr). The power bombarding the titanium target may be supplied by two power supplies, such as two RF generators or two medium frequency (MF) generators. The base 1 revolves around an axis outside the base 1 at 1.8 to 2.2 revolutions per minute (rpm), and rotates around its own axis at 7.2 to 8.8 rpm. This PVD process provides argon gas in a range from 360 to 440 sccm and nitrogen gas in a range from 18 to 22 sccm.
Accordingly, the colored device casing 10 of the present disclosure provides a desired color and metal texture. The chromaticity coordinate (L*, a*, b*) of the portion of the color layer 3 corresponding to and located over the smooth region of the base 1 is in the range from (about 57.57 to about 59.57, about 1.04 to about 2.04, about 6.64 to about 7.64) according to the CIE LAB system.
Furthermore, a coating layer 4 can be optionally formed on the color layer 3, according to any of various suitable techniques known in the art.
The colored device casing 10 of the present disclosure can be applied to any suitable object or device, such as a notebook or a personal digital assistant (PDA). For example, a mobile phone including the colored device casing 10 shown in
It is to be understood, however, that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail, especially in matters of arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 99101307 | Jan 2010 | TW | national |
This application is related to co-pending U.S. Patent Applications (Attorney Docket Nos. US32560, US32592, US32593, US32594, US32595, US32596, US32597, US32598, US32599, US32600, US32601, US32602, US32603, US32605, US32606 and US30607), all entitled “COLORED DEVICE CASING AND SURFACE-TREATING METHOD FOR FABRICATING SAME”, invented by Chen et al. Such applications have the same inventors and assignee as the present application.
