JP2007173585A - Electronic apparatus case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus case having high scratch resistance and high decorativeness. <P>SOLUTION: An electronic apparatus case 1 is formed from ceramics. At least the front surface is a mirror surface on which waves periodically appear. The front surface of electronic apparatus case 1 has high scratch resistance even when coming into contact with an object, because the electronic apparatus case 1 is formed from hard ceramics. A higher scratch-resistance effect can be achieved as a result of an effect of the periodic waves causing the traveling direction of the object coming into contact with the electronic apparatus case 1 to curve at the peak of the wave. Even when a scratch is made, the scratch is only made on the peaks of the waves on the front surface. Therefore, the scratch is difficult to visually recognize and is unnoticeable. Although there are waves, a diffused reflected light can be generated because the front surface is a mirror surface. Therefore, the electronic apparatus case 1 is highly decorative with a soft appearance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a case made of ceramics for electronic devices such as notebook computers, mobile phones, and digital cameras.

  Generally, polycarbonate resin, ABS resin, and the like are used for cases of electronic devices such as notebook computers, mobile phones, and digital cameras. This is widely adopted because of the formability capable of integrally molding complex shapes, the ability to reduce weight, and the possibility of multiple colors.

  In recent years, in particular, highly decorative resin cases with a metallic luster are becoming mainstream. For example, the case of a cellular phone is a molded product of synthetic resin, but the surface thereof is made of aluminum or nickel. By forming a transparent or translucent resin film mixed with particles of glittering metal, it is possible to provide a case that has a texture and high-class feeling like a brightness metal and further improves durability. It is disclosed (see Patent Document 1).

  However, the resin case described above is inferior in strength, hardness, heat resistance, and chemical resistance, and in terms of strength, the liquid crystal display part and internal circuits that are mounted by distorting when pressure is applied to the case of the electronic device. There was a problem of damage.

  As a method for solving these problems, by covering a metal plate with a transparent resin layer, it is possible to make up for the lack of strength of the resin and to provide a metallic shine and gloss. It is disclosed that it is suitable as a case of (Personal Digital Assistant) (see Patent Document 2).

  Similarly, there is a case of an electronic device in which a coating film containing titanium dioxide particles or alumina particles is formed on the surface of a metal member, and it is disclosed that heat absorption, heat dissipation, and antibacterial effect are brought about (Patent Document) 3).

In addition, a case is disclosed in which the engine portion can be replaced and used for several generations by using ceramics for the case of the mobile communication terminal without using such a resin material or metal material (see Patent Document 4). ).
JP 2000-349874 A JP 2004-228238 A JP 11-340639 A JP-T-2005-501434

  However, it is needless to say that the cases proposed in Patent Documents 1, 2, and 3 are inferior in heat resistance and chemical resistance, and the problem in particular is the scratch resistance. Although a metallic luster texture is obtained at this stage, when used as an electronic device, particularly a portable electronic device, there is a problem that it is inevitable to be damaged by dropping or touching, resulting in poor decorativeness.

  In addition, Patent Document 4 proposes using ceramics as a case material for a communication portable terminal such as a mobile phone, and the surface processing is usually performed by lapping, and in this case, pressure is applied to the surface. For this reason, since the abrasive grains move and polish while biting into the crystal grains on the surface, fine scratches are easily attached in various directions. Further, the lapping process is mainly intended to obtain a mirror surface state in order to enhance the decorativeness, but has a problem that the mirror surface has a very smooth finish and can only be a dazzling and glossy surface with reflected light.

  In view of the above problems, an object of the present invention is to provide an electronic device case having a soft gloss, high scratch resistance, and high decorativeness.

  The electronic device case of the present invention is characterized in that the surface is made of ceramics having a mirror surface having periodic waviness.

  The waviness is characterized in that the pitch is 20 μm or more and 500 μm or less, and the difference between the maximum value and the minimum value of the pitch on the same surface is 30 μm or less.

  Further, the waviness is characterized in that the average waviness is 0.07 μm or more and 10 μm or less, and the difference between the maximum value and the minimum value of waviness on the same surface is 0.4 μm or more and 2 μm or less.

  Still further, the ceramic is characterized by containing zirconia as a main component.

  The case for an electronic device of the present invention is made of ceramics, and the undulations on the surface periodically appear at a predetermined pitch and have a mirror surface. Therefore, even if an object contacts the surface of the case, it has high hardness. Since it is made of ceramics, it is possible to obtain a case having a scratch resistance effect even when it comes into contact with a metal material subjected to high hardness treatment. In addition, since the action of turning the traveling direction of the object in contact with the undulation peak works, it can have a further scratch resistance effect. In addition, even if scratches occur, the scratches are generated only on the undulations of the surface, making it difficult to see and conspicuous, and even if there are undulations, it is a mirror surface and can produce diffuse reflected light. Therefore, it is possible to provide a case for an electronic device with a soft mirror surface and a high decorative property.

  Further, since the undulation has a pitch of 20 μm or more and 500 μm or less, and the difference between the maximum value and the minimum value of the pitch on the same surface is 30 μm or less, the swell is bent in the traveling direction of the contact object causing the scratch. It is easy to obtain the effect of the above, and a high scratch resistance effect can be obtained, and color unevenness can be prevented.

  Further, the undulation has an average undulation of 0.07 μm or more and 10 μm or less, and the difference between the maximum value and the minimum value of undulation on the same surface is 0.4 μm or more and 2 μm or less. By making it into a certain range, it is easy to obtain the action of turning the traveling direction of the contact object causing the scratch, and it becomes easier to obtain the scratch resistance effect and can exhibit a mirror surface.

  Furthermore, when the ceramic is mainly composed of zirconia, high hardness can be secured, and multicolorization can be realized by appropriately selecting additives. In addition, even when used as a case of a portable electronic device, it can be used sufficiently without being easily broken.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A is an enlarged perspective view showing a part of an electronic device case (hereinafter simply referred to as case 1) 1 of the present invention, and FIG. 1B is a cross-sectional view taken along the line AA.

  As shown in FIG. 1, the surface of the case 1 has waviness W, and the waviness W has a pitch Wp, a maximum value Wpmax of the waviness W, a minimum value Wpmin, and a difference between Wpmax and Wpmin. Wpr, the average waviness in the height direction of the waviness W is Wa, the height based on this average waviness Wa is the waviness W, the maximum value is Wmax, the minimum value is Wmin, and the difference is Wr, The peak of the swell W is shown as Wy.

  In addition, the measuring method of each value of these waviness W is based on JIS B 0610, and the cut-off value is measured as fl8, fh0.8, measurement length 30 mm, measurement speed 0.5 mm / sec, vertical magnification 10000, and horizontal magnification 2. did.

  Here, it is important that the case 1 of the present invention is a mirror surface made of ceramics and having at least a surface having periodic waviness with a predetermined pitch.

  As the ceramics constituting the case 1, various types such as ceramics mainly composed of zirconia and alumina, ceramics composed of titanium carbide and titanium nitride cermets, and the like can be used.

In particular, it is preferable to use ceramics mainly composed of zirconia, and since it has higher hardness than metal materials, it has high scratch resistance. Furthermore, oxides such as nickel, cobalt, selenium, chromium, titanium, and iron are used as additives. This is because the choices of color tones such as green, blue, yellow, red, and black increase, and in addition, a texture not found in paint can be produced. Specifically, ceramics containing 90% by mass or more of zirconia as a main component and including a stabilizer, more specifically, zirconia (ZrO ₂ ) is 86 to 95% by mass, yttria (Y ₂ O ₃₎ which is comprising 4-6% by mass.

Further, the components of the ceramic raw material for obtaining case 1 of the present invention, the range of the content thereof, and the preferable particle size range of the powder are 86 to 93.5% by mass of zirconia (ZrO ₂ ), respectively, and a stabilizer. It is zirconia ceramics containing 4 to 6% by mass of a certain yttrium oxide (Y ₂ O ₃ ), and the particle size of each powder is 0.2 to 0.4 μm for zirconia and 0.3 to 0.6 μm for yttria. As other stabilizers, ceria is 0.5 to 0.8 μm, displo is 0.8 to 1.3 μm, and titanium carbide is 0.8 to 2.5 μm. Nickel having a particle size of 1.3 to 3 μm, cobalt of 1.5 to 4 μm, nickel oxide of 0.3 to 0.8 μm, cobalt oxide of 0.4 to 1.0 μm, 0.5 to 1.2 μm Cerium oxide, 0 Chromium oxide 3～0.8Myuemu, titanium oxide 0.2 to 0.6 [mu] m, to determine the color by selecting the oxide such as iron oxide 0.4～0.9Myuemu.

  Here, in the case of the present invention, the surface is specified as a mirror surface having periodic waviness W as shown in FIG.

  Waviness does not indicate irregularities due to ceramic crystal particles or irregularities due to surface defects such as pinholes and pores, but indicates surface conditions excluding these irregularities, and the surface has irregularities consisting of a smooth curved surface. Indicates that it appears continuously. Periodic waviness refers to a state in which the uneven pattern when measured by the surface shape measuring device is substantially the same at any location on the same surface of the case 1 and is arranged with regularity. Has the regularity, the difference Wpr between the maximum value Wpmax and the minimum value Wpmin of the pitch Wp of the undulation W measured at any location in the same plane is 45 μm or less, and the maximum of the undulation W in the height direction of the undulation W The difference Wr between the value Wpmax and the minimum value Wpmin is in the range of 0.3 μm to 2.5 μm. Further, the mirror surface here is a surface on which the objective contrast can be visually recognized on the surface of the case 1, and the maximum value of the Ra value measured at each position when the arithmetic average roughness Ra measured by JIS B0601 is 0.5 μm or less. The minimum value difference is 0.1 μm or less.

  Accordingly, since the material has sufficient hardness and has high scratch resistance, the waviness W on the surface of the case 1 appears periodically at a predetermined pitch Wp. Therefore, as shown in FIG. Even if the object 3 touches the surface in the direction of the arrow x and travels, the undulation Wy can be turned in a direction in which the traveling direction deviates from the surface. And has a higher scratch resistance effect. Further, even if the scratch 4 is generated, it is difficult to attach to the valley Wz of the swell W. Therefore, the scratch 4 generated on the mountain Wy becomes a perforated scratch 4 and can be hardly recognized. Furthermore, since there is a periodic swell W with a predetermined pitch Wp, the specularly reflected light beam 6 with respect to the incident light beam 5 can be moderately suppressed as shown in the sectional view of FIG. Since a glossy surface with different softness and high decorativeness is obtained and diffuse reflection light rays are generated, it becomes a soft mirror surface and can be made into a case with high decorativeness.

  The waviness W preferably has a pitch Wp of 20 to 500 μm, and a difference Wpr between the maximum value Wpmax and the minimum value Wpmin of the pitch Wp on the same surface is preferably 30 μm or less.

  Thereby, scratch resistance becomes higher and a beautiful surface without color unevenness can be obtained. When the pitch Wp of the undulations W is less than 20 μm, as shown in FIG. 2, the pitch 3 of the undulations Wp becomes narrower when the object 3 comes into contact with the surface of the case 1, and the object 3 that comes into contact with the ridges Wy of the undulations W Since only the apex of the contact is made, the action of turning the traveling direction in a direction deviating from the surface is reduced, so that the effect of suppressing the length of the scratch 4 is small and the large scratch 4 is likely to be attached. On the other hand, if the pitch Wp of the undulations W exceeds 500 μm, unevenness of reflected light along the pitches Wp of the undulations W will occur, and color irregularities can be discerned by human eyes, which is not aesthetically pleasing. At the same time, when the difference Wpr between the maximum value Wpmax and the minimum value Wpmin on the same surface of the pitch Wp of the undulation W exceeds 30 μm, even if the pitch Wp of the undulation W is within the range of 20 to 500 μm, Since the person recognizes the difference in the reflected light due to the difference in the pitch Wp of the undulations W, it feels as color unevenness. More preferably, the pitch Wp of the undulation W is 30 to 200 μm, the difference Wpr between the maximum value Wpmax and the minimum value Wpmin is 20 μm or less.

  Further, the waviness W has an average waviness Wa of 0.07 μm or more and 10 μm or less, and a difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W on the same surface is 0.4 μm or more and 2 μm or less. Is preferred.

  Here, the average waviness Wa is defined according to JIS B 0610, with the average waviness Wa having the same upper and lower areas in the cross-sectional curve of the waviness W shown in FIG. Since the average waviness Wa is 0.07 μm or more, it has moderate undulations within the range of the pitch Wp of the predetermined waviness W, and even if the object 3 contacts the surface of the case 1, it does not easily contact the valley Wz. Therefore, the scratch resistance can be further improved, and since the average waviness Wa is 10 μm or less, a mirror surface can be obtained with a small surface roughness.

  When the average waviness Wa is less than 0.07 μm, even if the pitch Wp of the waviness W is in the range of 20 to 500 μm, the undulation of the waviness W is small. The action of moving the direction of travel 3 away from the surface and turning is not sufficient. On the other hand, if the average waviness Wa exceeds 10 μm, the glossiness is inferior and the decorativeness is lowered. Furthermore, even if the average waviness Wa is in the range of 0.07 μm or more and 10 μm or less, if the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W on the same surface exceeds 2 μm, it is the same because it is perceived as unevenness on the mirror surface. The difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W on the surface is 2 μm or less. Further, when the difference Wr between the maximum value Wmax and the minimum value Wmin of the undulation W is less than 0.4 μm, the level of the undulation W is too small, and the object 3 is in contact with the surface of the case 1 as shown in FIG. In this case, the scratches 4 are easily attached to the valleys Wz of the swells W, and the action of turning the traveling direction of the object 3 in a direction deviating from the surface is reduced, so that the large scratches 4 are easily attached. Accordingly, since the surface can be easily felt as an uneven mirror surface, the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W is preferably 0.4 μm or more and 2 μm or less. More preferably, the average waviness Wa is 0.1 to 6 μm, and the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W is 0.5 μm or more and 0.7 μm or less.

  Next, a method for manufacturing the case 1 of the present invention will be described.

For example, first, a raw material powder containing yttria (Y ₂ O ₃ ) as a stabilizer in zirconia as a main component is obtained as a case 1 by a known powder dry press, powder rubber press or extrusion molding. .

  Next, the compact is fired at about 1300 to 1450 ° C. in an air atmosphere using a batch furnace or a continuous tunnel furnace to produce a sintered body. The cermet is fired at a temperature of about 1400 to 1550 ° C. using a vacuum furnace.

  Next, the case 1 of this invention is obtained by carrying out rough finishing process of the surface of a sintered compact with a rotation barrel, and then mirror-finishing processing with a centrifugal barrel. Further, blasting or the like may be combined as preprocessing.

  The case 1 made of zirconia ceramics has a mirror surface, and in order to obtain a desired pitch Wp of the waviness W and an average waviness Wa, a method of controlling by the particle diameter of the barrel processing media can be used.

  For rough finishing with a rotating barrel, a known rotating barrel device is used, and the water, media, and product input ratio is about 1: 1: 1, and the media is GC abrasive grains of about 5 to 10φ and the rotational speed is 50 to 100 rpm and 20 Process for ~ 50 hours. Thereafter, with a known centrifugal barrel, the amount of water, product, and media is set to about 1: 0.8: 0.5, and the media uses GC abrasive grains of 0.5 to 3φ at a rotational speed of 50 to 100 rpm and 10 to 30. Perform time finishing. The pitch Wp of the swell W of the case 1 increases as the media diameter increases. The average waviness Wa can be increased by increasing the number of revolutions and shortening the processing time.

  More specifically, in order to set the pitch Wp of the waviness W to about 20 μm, when the rough finishing condition is a rotating barrel apparatus, GC abrasive grains having a media diameter of about 5 μm are used, and the rotational speed is about 20 at about 100 rpm. When the time processing is performed, and then the mirror finish processing is performed by a centrifugal barrel, the processing may be performed for about 10 hours at a rotational speed of about 100 rpm using GC abrasive grains having a media diameter of about 0.5 μm. In addition, in order to set the pitch Wp of the undulation W to about 500 μm, in the case of a rotating barrel device, a GC abrasive grain having a media diameter of about 10φ is used, and the rotational speed is about 50 rpm for about 50 hours. When processing is performed by a centrifugal barrel, GC abrasive grains having a media diameter of about 3 μm are used, and the processing may be performed at a rotation speed of about 50 rpm for about 30 hours.

  In addition, in order to set the average waviness Wa to about 0.07 μm and the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W to 0.4 μm or more, the ratio of water, media and product to the rough-finished rotating barrel should be set. The ratio of water, media, and product in the drawing barrel for mirror finishing may be about 1: 0.5: 0.5. In addition, in order to set the average waviness Wa to about 10 μm and the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness W to 2 μm or less, the ratio of water, media, and product in the rough finishing rotary barrel is 1: 1. The ratio of water, media, and product in the drawing barrel for mirror finishing may be about 1: 1: 0.5.

  The method and conditions for the surface treatment are merely examples, and the present invention is not limited to this. However, the pitch Wp and the swell W described above can be obtained by variously combining the conditions for barrel polishing in this way.

  The case 1 produced in this manner is suitable for portable use that is susceptible to impacts such as falling or hitting because of its excellent scratch resistance and decorativeness. As an example of its use, a cellular phone, a digital camera, portable music playback There are portable electronic devices 2 such as devices, electronic pens, notebook personal computers, and mobile personal computers.

  Further, for example, when used as a case 2 for a portable electronic device, for example, the front surface 2b, the side surface 2c, and the back surface 2d constituting the case may be configured by the case 1 of the present invention, but a part thereof The other parts used only may be a combination of a conventional resin or metal case and may be appropriately selected.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

As a sample of the present invention, 94.8% by mass of zirconia (ZrO ₂ ) as a raw material powder, 5.2% by mass of yttrium oxide (Y ₂ O ₃ ) as a stabilizer, and green as a pigment additive Is added in combination with chromium oxide, black is combined with iron oxide, titanium oxide, nickel oxide, blue is combined with cobalt oxide, and pulverized and mixed with a solvent to prepare a slurry.

  And the compact | molding | casting which becomes the case 1 is produced by powder dry press of these slurries.

  Next, the compact was fired at about 1450 ° C. in an air atmosphere in a batch furnace to produce a sintered body.

  Next, the surface of the sintered body was rough-finished with a rotating barrel, and then mirror-finished with a centrifugal barrel. As described above, the conditions of the rotating barrel and the centrifugal barrel are as follows. Rough finishing with the rotating barrel uses a known rotating barrel device, the ratio of water, media, and product is about 1: 1: 1, and the media is about 5 to 10φ. Processing is performed for 20 to 50 hours at a rotational speed of 50 to 100 rpm using GC abrasive grains. Thereafter, with a known centrifugal barrel, the amount of water, product, and media is set to about 1: 0.8: 0.5, and the media uses GC abrasive grains of 0.5 to 3φ at a rotational speed of 50 to 100 rpm and 10 to 30. In the time finishing process range, the pitch Wp of the swell W of the case increases as the diameter of the media increases. Further, since the average waviness Wa is increased by increasing the number of revolutions and shortening the processing time, the waviness W has a pitch Wp of 7 to 500 μm and the average waviness Wa is 0.04 to 12 μm. Samples were prepared so as to have a combination of

  In addition to mirror finishing by barrel processing, samples for lapping and buffing were also added. The lapping treatment was performed by dissolving 1 g of free diamond abrasive grains (# 3000) in 500 cc of olive oil, instilling it on a copper disk, and treating with a known lapping apparatus at a rotation speed of 20 rpm for 10 hours. In addition, 1 g of free diamond abrasive grains (# 3000) was dissolved in 500 cc of olive oil and dropped on a buffing machine, and buffing was performed at a rotation speed of 1000 rpm for 1 hour.

  Moreover, what was produced with SUS304 as a comparative example was made into sample number 40. FIG.

The surface waviness W is measured for each sample of the example manufactured as described above, the pitch Wp of the waviness W, the maximum value Wpmax of the pitch Wp, the difference Wpr of the minimum value Wpmin, the average waviness Wa, the maximum waviness. A difference Wr between the value Wmax and the minimum value Wmin was obtained. The measurement method was based on JISB0610, and the cutoff values were fl8, fh0.8, measurement length 30 mm, measurement speed 0.5 mm / sec, vertical magnification 10,000, and horizontal magnification 2. (The measuring instrument used was a surface roughness meter ET4000A manufactured by Kosaka Laboratory, which was measured with a non-contact laser stylus.)
The waviness W was measured in an arbitrary direction because the same waviness W cross-section curve was obtained for any mirror-finished barrel process. However, in the case of mirror finishing by lapping and buffing, since the processing flaw is visually recognized in one direction, the waviness W was measured in a direction orthogonal to the processing flaw.

  The Vickers hardness of each sample was also measured. Vickers hardness was measured according to JIS-R1610 using an AVK-A type hardness meter manufactured by Akashi Seisakusho and HvLoad of 10 kg.

  Next, a scratch resistance test was performed on each sample. The test method uses a scratch tester manufactured by HEIDON, and the measurement speed is 5 mm / sec. With a diamond needle having a vertical load of 500 g and a tip curvature radius of 2 μmR. In this method, a scratch-like scratch 4 having a length of 30 mm is applied. And the width | variety used as the maximum of this damage | wound 4 was measured by 10 time magnification with the tool microscope. The advancing direction of the scratch tester needle can be any direction when the mirror finish is barrel-processed, and the direction parallel to the direction perpendicular to the processing flaw is for lapping and buffing. Carried out on the street.

  Then, as shown in FIGS. 4 (a) and 4 (b), the measurement value of the wound 4 is about a position L1 of about 5 mm from the start point of the needle, a position L2 of about 15 mm, with respect to the wound 4 having a measurement length L of 30 mm. The widths D1, D2, and D3 of the position L3 of about 30 mm were measured, and the average value was used as data. When the scratch 4 is perforated, the maximum value of the latest scratch 4 applied to the measurement positions L1, L2, and L3 is used as data, and when the position is outside the perforated scratch 4, the nearest The maximum value of wound 4 was used as data.

  Moreover, about the visibility of the said scratch-like wound 4, visibility evaluation was performed whether three people can visually recognize from a distance of 10 cm. Illumination uses halogen light, ◎ if it is invisible, ○ if it is slightly visible, △ if it is visible, × if it is easily visible, and because it is an ambiguous evaluation, The median value was used as data.

  Next, the glossiness of the surface of each sample was measured. The method was measured according to JISZ8741 at 60 degrees using a UGV5D digital declination glossiness meter manufactured by Suga Test Instruments.

  In addition, the sensory evaluation felt by people on the mirror surface was also performed. The method is based on the visual sense of three people. When a sample is placed under incandescent light and viewed from the same distance, the soft mirror surface is ◎, the non-problematic mirror surface is ○, and the cloud is slightly cloudy. What was obtained was indicated by Δ, and what was not specular or dazzled was indicated by ×. Since this is also an ambiguous evaluation, the median value of three evaluations was used as data.

The above measurement results and human sensory evaluation results are shown in Table 1.

  As apparent from the results in Table 1, sample numbers 1 to 6, 8, 10, 11, 13 to 16, 18 to 23, 25 to 33, 35, 36, and 38 of the examples of the present invention are made of ceramics. In addition to having a Vickers hardness as high as HV12 GPa or more because it is made of a mirror surface having periodic waviness W of a predetermined pitch (pitch Wp of waviness W is 45 μm or less, waviness difference Wr is 0.3 to 2.5 μm), The waviness W produces a scratch resistance effect, and a glossy surface having a softness different from the metallic luster is obtained.

  Among these samples, those in which the pitch Wp of the undulation W is in the range of 20 to 500 μm are excellent in scratch resistance, and further, sample numbers 10, 11, 13, 14, 15, 16 having a pitch Wp in the range of 30 to 200 μm. No. 18 has a high scratch resistance because the width of the scratch 4 by the scratch tester is suppressed to 5 μm or less.

  In addition, when the average waviness Wa is 0.07 to 10 μm and the difference Wr between the maximum value Wmax and the minimum value Wmin of the waviness is 0.4 to 2.0 μm, the mirror surface has no cloudiness, and the average Sample numbers 4-6, 10, 11, 18-21, 25, 26, 29-31, in which the waviness Wa is in the range of 0.1-6 μm, have a glossiness of 80-90% and human sensory evaluation The mirror surface was soft.

  On the other hand, a sample outside the scope of the present invention, sample number 40 made of SUS material, has a low Vickers hardness of HV2.8 and a large swell difference Wr of 6 μm. The sensory evaluation of the mirror surface is not good due to the high degree of glare.

  In sample No. 7, the mirror surface processing is performed by lapping, and the periodic waviness W with a predetermined pitch Wp is only in one direction. Therefore, the waviness difference Wr is as small as 0.1 μm, and lapping processing is performed. It was found that when the scratch tester needle was run in the direction parallel to the scratch, the average value of the width D of the scratch 4 was as large as 55 μm and the scratch resistance was poor. Further, since the difference Wr of the waviness of Sample No. 9 was as small as 0.2 μm, it was found that although the width of the scratch was small, the scratch was conspicuous and inferior in scratch resistance.

  Sample No. 12 is mirror-finished by buffing and, like Sample No. 7, the periodic waviness W with a predetermined pitch Wp is only in one direction. When the needle is run, the average value of the width D of the scratch 4 is as large as 40 μm, and the scratch resistance is poor. Further, both the average waviness Wa was as large as 12 μm and the difference Wpr in the pitch Wp was as large as 36 μm.

  In Sample Nos. 17, 24, and 34, the difference Wr between the maximum value Wmax and the minimum value Wmin of the swell W was as large as 2.8 μm or more, and thus the mirror surface was clouded. In Sample No. 34, the average waviness Wa was as large as 12 μm, so that the mirror surface was clouded. Sample No. 37 had a large difference in pitch Wp Wpr of 50 μm and uneven gloss, resulting in the mirror surface being cloudy.

  Furthermore, it was found that Sample No. 39 made of SUS material has large scratches and poor gloss because the difference Wr between the maximum value Wmax and the minimum value Wmin of the swell W is as large as 6 μm and the Vickers hardness is small.

  As described above, the case of the present invention is made of a ceramic having high hardness, and has a mirror surface having a periodic waviness W having a predetermined pitch. A glossy surface can be obtained, and a highly decorative case can be provided.

It is a schematic diagram of the waviness cross-sectional curve of the surface of the case for electronic equipment of the present invention, (a) is a partially enlarged perspective view of the surface, (b) is a cross-sectional view along the AA line. It is a cross-sectional schematic diagram when an object contacts the surface of the case for electronic devices of this invention. It is a cross-sectional schematic diagram of the incident light and reflected light in the surface of the case for electronic devices of this invention. (A), (b) is an enlarged top view of the damage | wound in the surface of the case for electronic devices.

Explanation of symbols

1: Case 2: Case for portable electronic device 2a: Front surface 2b: Front surface 2c: Side surface 2d: Back surface 2e: Display unit 2f: Operation unit 3: Object 4: Scratch 5: Incident light beam 6: Regular reflection light beam 7: Diffuse reflection Rays

Claims (4)

A case for electronic equipment, characterized in that the surface is made of a ceramic which is a mirror surface having periodic undulations. 2. The electronic device case according to claim 1, wherein the swell has a pitch of 20 μm or more and 500 μm or less, and a difference between a maximum value and a minimum value of the pitch on the same surface is 30 μm or less. 2. The undulation is characterized in that the average undulation is 0.07 μm or more and 10 μm or less, and the difference between the maximum value and the minimum value of undulation on the same surface is 0.4 μm or more and 2.0 μm or less. Or the case for electronic devices of 2. The case for electronic equipment according to claim 1, wherein the ceramic is mainly composed of zirconia.

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