Shadow frame manufacturing method and shadow frame implemented thereby

Abstract

A shadow frame manufacturing method is provided. Accordingly, material costs and process costs can be significantly reduced by adopting a method of assembling each plate cut in a predetermined size in the shape of a shadow frame and then bonding same, and shadow frames of various sizes can be freely implemented. In addition, the implemented shadow frame has physical properties such as excellent hardness and corrosion resistance, and can greatly reduce a difference in different colors between the color of a bonded portion and the original color of the non-bonded rectangular plate, thereby being advantageous in preventing deterioration in marketability due to different colors.

Description

Shadow frame manufacturing method and shadow frame implemented thereby

[0001] The present invention relates to a method for manufacturing a shadow frame and a shadow frame implemented thereby.

[0002] Modern semiconductor devices are manufactured using a process that deposits and removes multiple layers of conductive, semiconducting, and dielectric materials from a glass substrate to produce components such as OLEDs, transistors, and low-k dielectric films.

[0003] Here, the techniques performed on the glass substrate include plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), and etching. Generally, the process using plasma includes the step of placing the substrate on a support member (or referred to as a susceptor or heater) arranged in a vacuum chamber, and forming plasma adjacent to the upper exposed surface of the substrate to deposit the desired material. Meanwhile, in this step, not only the internal chamber components but also the undesired areas such as the edge and backside of the glass substrate must be protected from the deposition, and for this purpose, a deposition masking device, or shadow frame, is arranged around the periphery of the substrate to prevent the process gas or plasma from reaching the edge and backside of the substrate during the plasma process, and to maintain the substrate on the support member.

[0004] Shadow frames that perform these functions, as shown in Fig. 1, have been conventionally implemented by forming an opening in the center of a single plate body cut to a size acceptable for a chamber and machined on the inside to a size corresponding to the area where deposition takes place. However, this conventional shadow frame manufacturing method has the problem that it is uneconomical and inefficient because a lot of material is wasted and a lot of energy is consumed in processing, considering the rising material costs, the trend toward larger deposition areas, and the resulting larger shadow frames.

[0005] Therefore, there is an urgent need for research on a method to manufacture shadow frames with good quality while using lower material costs and energy, i.e. reducing greenhouse gases.

[0006] The present invention has been devised in consideration of the above points, and its purpose is to provide a manufacturing method capable of freely implementing a desired size with lower material cost and manufacturing cost compared to conventional manufacturing methods, and a shadow frame manufactured through the manufacturing method.

[0007] In addition, another purpose of the present invention is to provide a method for manufacturing a shadow frame, in which the implemented shadow frame has excellent hardness, corrosion resistance, and other characteristics, and no appearance abnormalities such as color change occur in each area, and a shadow frame manufactured through the method.

[0008] In order to solve the above-described problem, the present invention provides a method for manufacturing a shadow frame, comprising the steps of (1) arranging four aluminum plates in a square frame shape forming an opening therein, and arranging blocks for protecting the parent material on both sides of the boundary portion between the four arranged plates, (2) performing friction stir welding for joining on each of the upper and lower surfaces of the boundary portion between the plates, (3) heat-treating the welded square frame, and (4) anodizing the square frame.

[0009] According to one embodiment of the present invention, the plate may be an aluminum alloy of the 2000 series, 5000 series, 6000 series or 7000 series.

[0010] In addition, a step of performing rough machining on an area where welding is performed in step (2) between steps (1) and (2) and a step of performing cutting machining on a surface to be anodized between steps (3) and (4) may be further included.

[0011] In addition, in order to minimize surface discoloration between the welded and non-welded portions between steps (2) and (3), a step of performing cosmetic friction stir welding with an insertion depth of less than half the tool insertion depth of the friction stir welding for joining performed in step (2) may be further included for the welded portions formed on the upper and lower surfaces, respectively.

[0012] Additionally, the heat treatment can be performed at a temperature of 200 to 600°C for 2 to 6 hours.

[0013] In addition, step (4) may perform mixed acid anodization using sulfuric acid and hydroxide to minimize surface discoloration between the welded and non-welded areas.

[0014] Additionally, mixed acid anodic oxidation can be performed at a voltage of 70 to 90 V for 2200 to 5000 seconds in an electrolyte containing 3 to 7 wt% of oxalic acid and 0.1 to 0.5 wt% of sulfuric acid.

[0015] In addition, the above-mentioned friction stir welding for cosmetics can be performed at an insertion depth of 1 / 3 to 1 / 2 or less of the tool insertion depth of friction stir welding for joining.

[0016] In addition, after step (4), one or more processes of sealing treatment and heat treatment may be further performed.

[0017] In addition, the present invention provides a shadow frame manufactured by a manufacturing method according to the present invention.

[0018] The shadow frame manufacturing method of the present invention adopts a method of assembling and bonding plates cut to a predetermined size into the shape of a shadow frame, unlike conventional manufacturing methods, thereby drastically reducing material and process costs, and freely implementing shadow frames of various sizes. In addition, the implemented shadow frame has excellent physical properties such as hardness and corrosion resistance, and can significantly reduce the discoloration difference between the color of the bonded portion and the original color of the non-bonded plates, thereby advantageously preventing a decline in marketability due to discoloration.

[0019] Figure 1 is a schematic diagram of the manufacturing process of a conventional shadow frame.

[0020] FIG. 2 and FIG. 3 are schematic diagrams of step (1) of a shadow frame manufacturing process according to one embodiment of the present invention. FIG. 2 is a schematic diagram of each plate arranged in a square frame shape, and FIG. 3 is a schematic diagram of each plate arranged with a block for protecting the parent material.

[0021] FIG. 4 is a photograph of four boundary portions after friction stir welding on the upper surface in step (2) of a shadow frame manufacturing process according to one embodiment of the present invention.

[0022] FIG. 5 is a photograph of four boundary portions after friction stir welding on the lower surface in step (2) of a shadow frame manufacturing process according to one embodiment of the present invention.

[0023] Fig. 6 is a photograph of a manufacturing process of a shadow frame according to one embodiment of the present invention, and is a photograph of one boundary of the shadow frame after friction stir welding for joining is completed.

[0024] Fig. 7 is a photograph of a manufacturing process of a shadow frame according to one embodiment of the present invention, and is a photograph of a shadow frame that has completed friction stir welding for cosmetics and heat treatment after friction stir welding for bonding.

[0025] FIG. 8 is a photograph of a shadow frame after completion of a manufacturing process of a shadow frame according to one embodiment of the present invention, and is a photograph of a boundary portion of a shadow frame after performing heat treatment after friction stir welding for joining and friction stir welding for cosmetics and completing anodization using a mixed-acid method.

[0026] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0027] A shadow frame according to one embodiment of the present invention can be manufactured by including the steps of (1) arranging four aluminum plates in a square frame shape having an opening on the inside, (2) performing friction stir welding for joining the upper and lower surfaces of the boundary portions where the plates come into contact, (3) heat-treating the welded square frame, and (4) anodizing the square frame.

[0028]

[0029] Referring to FIG. 1, step (1) according to the present invention includes a step of arranging four aluminum plates (10) in a square frame shape having an opening on the inside.

[0030] The above plate (10) is a part that constitutes the body of the shadow frame, and may be a material of a shadow frame that is commonly used, for example, an aluminum alloy material, and specifically, the aluminum alloy may be a 2000 series, a 5000 series such as Al5052, a 6000 series such as Al6061, or a 7000 series.

[0031] In addition, the thickness of the above plate (10) may be within the thickness range of a commonly used shadow frame, for example, 10 to 50 mm, but is not limited thereto.

[0032] In addition, the width and length of the above plate (10) can be appropriately adjusted in consideration of the area of ​​the accommodation space and the area of ​​the deposition area in the plasma deposition equipment, and therefore the present invention is not particularly limited thereto.

[0033] Meanwhile, the above plate (10) may further undergo a known pretreatment process for the portion where friction stir welding for joining will be performed in step (2) described below prior to performing step (1). The above pretreatment process may be, for example, washing, grinding, etc., and the present invention is not particularly limited thereto.

[0034]

[0035] The four prepared plates are arranged in a square frame shape, and the present invention is not particularly limited with respect to the specific arrangement form. For example, as illustrated in Fig. 2a, one longitudinal end surface of a plate arranged horizontally or vertically may be arranged to form the outer surface of the square frame. Alternatively, a pair of plates may be arranged vertically or horizontally between a pair of plates arranged horizontally or vertically, so that the outer surface of the square frame is formed by the longitudinal side surfaces of the four plates.

[0036] In addition, in order to prevent damage to the base material due to friction stir welding to be performed in step (2) described later, a base material protection block (11) may be placed on each side of the boundary between the four plates (10) arranged as shown in Fig. 2b, so that a total of eight base material protection blocks may be placed.

[0037]

[0038] Next, as step (2) of the present invention, a step of performing friction stir welding for joining is performed on each of the upper and lower surfaces of the boundary portion between the plates.

[0039] Friction stir welding (FSW) is a joining method that utilizes heating and plastic flow caused by friction. Compared to melting welding such as arc welding and laser welding, it is a non-consumable joining method that does not generate pores or cracks and does not use filler metal or shielding gas. In addition, it is environmentally friendly and consumes less energy, so it can produce high-quality joints without welding defects, noise, or harmful light. The principle of friction stir welding is that a rotating tool is pressed into the joining surface of the materials and the shoulder is compressed, generating frictional heat and pressure between the tool and the material. When a mechanical force is applied to move the tool, the heated part is extruded from the front (advancing side) of the pin to the back (retreating side), and the rear flowing part of the tool is rapidly cooled by heat conduction to form a solid-state weld.

[0040]

[0041] Regarding the area where friction stir welding is performed, as shown in FIGS. 2 to 5, the area where joining is required is to perform friction stir welding for joining for a total of eight boundary portions, four on each of the upper and lower surfaces, and friction stir welding can be performed in one direction from one end to the other centered on the boundary portion. At this time, preferably, in order to protect the base material and improve the welding quality, as described above, a pair of base material protection blocks (11) are placed so as to be in contact with one side of the boundary where welding starts and the opposite side where welding ends, and the tool used for friction stir welding is positioned on the base material protection blocks (11), and then friction stir welding is started from one base material protection block (11) and completed on the other base material protection block (11) on the opposite side, thereby welding so that the boundary portion is placed in the middle of the welding path, thereby improving the welding quality.

[0042]

[0043] In addition, in step (2), friction stir welding for joining can be performed using a commercially available friction stir welding device. At this time, friction stir welding for joining can be performed so that the tool's stirring speed (spin rate) is 400 to 800 rpm, the moving speed (feed rate) is 80 to 200 mm / min, and the tool's insertion depth is 0.4 to 0.6 times the thickness of each plate, which is advantageous in obtaining a good joint with high joining strength and minimized joining deformation.

[0044]

[0045] According to one embodiment of the present invention, a step of performing rough machining on the area where welding is performed in step (2) may be further included between steps (1) and (2). The rough machining may be performed on the surface of each plate (10) on which friction stir welding is performed, and thereby may be advantageous in improving the bondability and welding quality of friction stir welding.

[0046]

[0047] Next, the present invention performs a step of heat treating the welded square frame as step (3).

[0048] Heat treatment can help to improve the appearance quality deterioration caused by the difference in color between the welded and non-welded surfaces after step (2), thereby minimizing the discoloration between the welded and non-welded surfaces and making the hardness uniform between the welded and non-welded surfaces. In addition, it can prevent problems such as deposition unevenness and other problems deteriorating deposition quality caused by surface discoloration between the welded and non-welded surfaces in the deposition process where a shadow frame is applied.

[0049] The above heat treatment can be performed, for example, in an air atmosphere. In addition, the heat treatment can be performed at a temperature of 200 to 600°C for 2 to 6 hours, which can be advantageous in minimizing discoloration. If the heat treatment temperature is lower than 200°C and / or for less than 2 hours, it may be difficult to minimize discoloration, and if the heat treatment temperature exceeds 600°C and / or for more than 6 hours, there is a concern that the hardness may be significantly reduced.

[0050]

[0051] According to one embodiment of the present invention, in order to further minimize discoloration between the welded portion and the non-welded portion between the steps (2) and (3) described above, cosmetic friction stir welding may be further performed on the welded portions formed on the upper and lower surfaces, respectively.

[0052] Friction stir welding for cosmetics can significantly reduce the discoloration that remains even after the heat treatment in step (3), thereby further improving the appearance quality. Preferably, friction stir welding for cosmetics can be performed with an insertion depth of less than half the insertion depth of the friction stir welding for joining performed in step (2), and more preferably, it can be performed with an insertion depth of less than 1 / 3 to 1 / 2. If friction stir welding for cosmetics is performed with an insertion depth exceeding 1 / 2 of the insertion depth of the friction stir welding for joining, the discoloration of the weld may not be improved, and rather, the discoloration may be aggravated. In addition, if friction stir welding for cosmetics is performed with an insertion depth less than 1 / 3 of the insertion depth of the friction stir welding for joining, the improvement in discoloration may be minimal.

[0053]

[0054] After the heat treatment process of step (3) described above, a step of cutting and processing the surface of the square frame can be performed.

[0055] The above cutting process can be performed without limitation as long as it is a known cutting process for processing the surface of an aluminum-based material. For example, the above cutting process can perform at least one of roughing, finishing, and surface finishing, and the specific methods, equipment, etc. for each of these processes can be performed using known methods and equipment for each of these processes, and the present invention is not particularly limited thereto.

[0056]

[0057] Next, as step (4) of the present invention, a step of anodizing a square frame is performed.

[0058] By performing anodic oxidation on a square frame, an oxide film can be formed on the surface of the square frame, which can improve the chemical resistance and wear resistance of the shadow frame required when performing a deposition process such as PECVD.

[0059] Meanwhile, the above anodic oxidation may be performed by performing a pretreatment process before performing anodic oxidation, and the pretreatment process may be a pretreatment process typically performed before anodic oxidation of an aluminum alloy material, so the present invention is not particularly limited thereto.

[0060] For example, the above pretreatment process may perform at least one of a degreasing, etching, and desmutting process, and each of these pretreatment processes may be performed through a method known as a pretreatment process for aluminum alloy materials, so the present invention is not particularly limited thereto.

[0061] For example, the degreasing process is a process for removing foreign substances and oil components present on the surface of a square frame, and this can be carried out in the same manner as a conventional process. The degreasing process can be carried out, for example, by immersing the square frame in a degreasing solution or by an electrolytic degreasing method in which a voltage is applied after immersion. At this time, the degreasing solution used for immersion degreasing or electrolytic degreasing is preferably to contain at least one selected from sodium carbonate, sodium hydroxide (NaOH), and a surfactant. In addition, the degreasing solution is preferably a solution containing an anionic surfactant such as ethoxylated nonylphenol. Anionic surfactants are effective in removing oil components. For example, the degreasing solution can be composed of an aqueous solution containing 80 to 150 g / L of sodium carbonate (Na2CO3), 80 to 150 g / L of sulfuric acid (H2SO4), and 2 to 7 ml / L of an anionic surfactant based on 1 liter (L) of the total degreasing solution.

[0062] In addition, during electrolytic degreasing, the square frame may be immersed in a 10 to 15 wt% degreasing solution at 40 to 60°C for 1 to 10 minutes and then electrolytic degreasing may be performed for 1 to 5 minutes under a current density of 1 to 2 A / d㎡, more preferably, immersed in a 12 to 15 wt% degreasing solution at 50 to 55°C for 3 to 5 minutes and then electrolytic degreasing may be performed for 1 to 3 minutes under a current density of 1 to 2 A / d㎡, and additionally, washing may be performed after electrolytic degreasing.

[0063]

[0064] Next, the etching process is a process for removing an oxide film or oxidizable metal formed on the surface of a chromium-containing alloy component, and this can be performed using a conventional alkaline etching method. For example, the etching can be alkaline etching, and can be performed using a general alkaline etching solution and conditions used in the art. For example, alkaline etching can be performed by immersing a degreased pretreatment target in a 3 to 12 wt% sodium hydroxide aqueous solution at 20 to 80°C for 1 to 7 minutes, and then washing.

[0065] Meanwhile, acid etching may be further performed as an etching process. Acid etching may remove components such as silicon that may interfere with the formation of an oxide film, and may perform an additional cleaning function to prevent the shadow frame from affecting the process in which it is used. The acid etching may be performed after alkaline etching, but may also be performed after the desmut process described below, and the present invention is not particularly limited thereto. The acid etching may be performed by a general acid etching method used in the art. For example, acid etching may be performed by immersing the film in an aqueous solution of nitric acid having a concentration of 1 to 50 wt% and hydrofluoric acid having a concentration of 0.5 to 7 wt% at 20 to 30°C for 15 seconds to 2 minutes, and then washing.

[0066]

[0067] Next, the desmut process is a step for removing smut remaining on the etched square frame surface, and can be performed using a common method used in the art. For example, the first smut removal process can be performed by immersing the alkali-etched pretreatment target in a nitric acid aqueous solution with a concentration of 10 to 60 wt% at 15 to 30°C for 1 to 2 minutes, and then washing it.

[0068]

[0069] After the above-described pretreatment process, anodization can be performed on the square frame. The anodization can be performed using a known anodization method, such as an oxalic acid method, a sulfuric acid method, or a mixed acid method using a mixed electrolyte of oxalic acid and sulfuric acid. Each of these anodization methods can appropriately adopt known electrolyte compositions, voltage / temperature / time, and other anodization conditions, and thus the present invention is not particularly limited thereto.

[0070] However, according to one embodiment of the present invention, in order to improve the surface discoloration between the welded and non-welded portions described above, the anodizing may be anodizing by a mixed acid method. To this end, the anodizing by the mixed acid method may be performed at a voltage of 70 to 90 V for 2200 to 5000 seconds in an electrolyte containing 3 to 7 wt% of oxalic acid and 0.1 to 0.5 wt% of sulfuric acid at a temperature of 15 to 25°C, thereby improving chemical resistance through anodizing while also significantly improving the surface discoloration between the welded and non-welded portions. If the anodizing by the mixed acid method deviates from the exemplified conditions, the effect of improving the surface discoloration may be minimal.

[0071]

[0072] According to one embodiment of the present invention, after step (4), at least one of a sealing process and a heat treatment process may be further performed, and more preferably, both a sealing process and a heat treatment process may be included, and the sealing process may be performed before the heat treatment.

[0073] The above sealing process is intended to seal micropores within an anodized film formed on an aluminum alloy surface, and any known sealing process that can be performed on an anodized film formed on an aluminum alloy surface can be used without limitation. Preferably, the sealing process can be performed by immersing the square frame in a bath containing a boiling water sealing solution or by treating the square frame with a boiling water sealing solution.

[0074] The above boiling water sealing treatment solution may contain an additive in ultrapure water, or may contain an additive and a surfactant in ultrapure water.

[0075] The above additive has the function of adjusting the pH of the boiling water sealing solution and preventing stains, and may include at least one selected from acetic acid, formic acid, and citric acid. In addition, the additive may be contained at a concentration of 1 to 10 ml / L, preferably 2 to 8 ml / L, and more preferably 2 to 5 ml / L per 1 L of the boiling water sealing solution. At this time, if the concentration of the additive is less than 1 ml / L, there is a concern that stains may frequently occur on the surface of the anodized film, which may aggravate the discoloration. In addition, if the concentration of the additive exceeds 10 ml / L, the sealing degree may be reduced due to a change in the pH of the sealing solution.

[0076] Additionally, the boiling water sealing solution may further include a surfactant to improve acid resistance. The surfactant may preferably include a compound represented by the following chemical formula 1.

[0077] [Chemical Formula 1]

[0078]

[0079] In chemical formula 1, R 1 is a straight-chain alkyl group of C8 to C18 or a branched alkyl group of C10 to C20, preferably R 1 is a straight-chain alkyl group of C9 to C16 or a branched alkyl group of C10 to C16, more preferably R 1 is a straight-chain alkyl group of C10 to C14.

[0080] Also, M of chemical formula 1 + is a monovalent cation, preferably Na + or K + and more preferably Na + am.

[0081] When a surfactant is contained in the boiling water sealing solution, it may be contained at a concentration of 1 to 12 g / L, preferably 2 to 10 g / L, and more preferably 4 to 10 g / L per 1 L of the boiling water sealing solution. If the concentration of the surfactant is less than 1 g / L, the effect of improving acid resistance may be minimal, and if the concentration exceeds 10 g / L, there is a concern that the effect of the boiling water sealing may be halved.

[0082] In addition, the boiling water sealing process can be performed at a temperature of 85 to 100℃ for 30 to 200 minutes, preferably at a temperature of 90 to 100℃ for 30 to 120 minutes. At this time, if the sealing process temperature is lower than 85℃, the sealing process efficiency is reduced, and in the case of the boiling water sealing process liquid containing a surfactant, it may be difficult to exhibit a sufficient acid resistance improvement effect. In addition, in order for the temperature of the sealing process to exceed 100℃, an additional pressure device is required, which not only increases the cost of production facilities, but also there is a concern that cracks may occur in the anodized film due to the sealing process at a high temperature.

[0083]

[0084] In addition, the heat treatment process may be performed after the sealing process to improve the hardness of the anodized film that has been sealed on the square frame. Specifically, the heat treatment process may be performed on the square frame that has been sealed at a temperature of 300 to 400°C for 30 to 150 minutes, which may be advantageous in exhibiting high hardness characteristics.

[0085]

[0086] The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

[0087]

[0088] <Example 1>

[0089] Two Al6161 plates each measuring 2.9 m in length, 0.2 m in width, and 25.4 mm in thickness, and two Al6161 plates each measuring 2.4 m in length, 0.2 m in width, and 25.4 mm in thickness, were prepared. After washing and drying the prepared plates, a roughing process was performed on the joint surface at the boundary where the plates were to be joined when arranging them as shown in Fig. 2 using a conventional method.

[0090] After that, the plates were arranged as shown in Fig. 2, and a pair of parent material protection blocks were placed on each side of one of the boundaries between the plates as shown in Fig. 3, and friction stir welding for joining was performed on a total of eight boundaries on the upper and lower surfaces between the plates arranged in a square frame shape. At this time, welding was performed from the parent material protection block placed on one side of the boundary where joining was to begin, and welding was completed at the parent material protection block placed on the other side, thereby performing joining of the boundary. At this time, the conditions for friction stir welding for joining were a stirring speed of 600 rpm, a feed rate of 120 mm / min, and an insertion depth of 14 mm.

[0091] Friction stir welding for cosmetics was then performed. Specifically, friction stir welding for cosmetics was performed with the tool probe passing through the weld area at a stirring speed of 600 rpm, a feed rate of 240 mm / min, and an insertion depth of 6 mm.

[0092] Afterwards, the square frame was heat-treated at 400℃ for 4 hours and then naturally cooled. Then, the surface of the square frame was subjected to rough grinding, finishing, and surface finishing using conventional methods, and then cleaned.

[0093] Afterwards, a pretreatment process before anodization was performed, and specifically, alkaline degreasing, cleaning, alkaline etching, cleaning, desmut, and cleaning processes were performed using conventional methods.

[0094] Afterwards, in order to perform anodization on the pretreated square frame, the frame was subjected to anodization in a 20°C electrolyte containing 4.7 wt% oxalic acid and 0.2 wt% sulfuric acid at a final applied voltage of 75 to 88 V for a total of 4,000 seconds, then washed and naturally dried to manufacture a shadow mask.

[0095]

[0096] <Examples 2 to 4>

[0097] A shadow mask was manufactured in the same manner as Example 1, but the cosmetic friction stir welding was not performed as shown in Table 1 below, or the type of anodic oxidation was changed to the sulfuric acid method or the oxalic acid method as shown in Table 1 below.

[0098] At this time, in the case of the sulfuric acid method, it was put into an electrolytic cell containing a sulfuric acid solution with a concentration of 15% by volume, and then -2℃ and a current density of 2.5 A / dm 2 The anodic oxidation method was performed under the conditions of

[0099] In the case of the water method, after putting it in an electrolytic cell containing a 3 wt% water solution, DC voltage was applied at 15℃, and a current density of 1.5 A / dm was applied in a constant current manner. 2 After increasing to , the current density is 1.5 A / dm 2 Anodization was performed for 2500 seconds.

[0100]

[0101] <Comparative Example 1>

[0102] A shadow mask was manufactured in the same manner as in Example 1, but heat treatment and anodic oxidation were not performed.

[0103]

[0104] <Experimental Example>

[0105] The degree of surface discoloration between the welded and unwelded portions of the shadow masks according to the examples and comparative examples was evaluated using the following physical properties, and the results are shown in Table 1 below.

[0106] Specifically, the degree of surface discoloration was measured five times for redness (a: redness) and yellowness (b: yellowness) for each welded and unwelded area using a Minolta CR-300 colorimeter (Minolta, Japan), and then the average value of saturation calculated according to Equation 1 below was calculated using the redness and yellowness, and the absolute value of saturation between the welded and unwelded areas was shown in Table 1 below.

[0107] [Formula 1]

[0108]

[0109] The larger the absolute value of the saturation between the welded and non-welded areas, the greater the degree of discoloration between the welded and non-welded areas, and the closer it is to 0, the less surface discoloration there is.

[0110]

[0111] Absolute value of the difference in saturation between the welded / non-welded area of ​​friction stir welding heat treatment for cosmetics. Example 1: Performed at 400°C / 6 hours. Sulfuric acid-oxalic acid mixed acid method. 0.72. Example 2: Performed at 400°C / 6 hours. Sulfuric acid method. 4.24. Example 3: Performed at 400°C / 6 hours. Sulfuric acid-oxalic acid mixed acid method. 3.95. Example 4: Not performed at 400°C / 6 hours. Sulfuric acid-oxalic acid mixed acid method. 3.53. Comparative example 1: Not performed. Not performed. Sulfuric acid-oxalic acid mixed acid method. 6.50.

[0112] As can be seen in Table 1,

[0113] It can be seen that the examples have significantly superior appearance quality according to the color difference between the welded and non-welded parts compared to Comparative Example 1, and among the examples, the appearance quality of Example 1, which performed friction stir welding for cosmetics and performed heat treatment and anodization using a sulfuric acid-oxalic acid mixed acid method, is particularly superior, and it can be expected that it will not affect the deposition quality when applied to a deposition process such as PECVD.

[0114]

[0115] Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the spirit of the present invention will be able to easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same spirit, but this will also be considered to fall within the spirit of the present invention.

Claims

1. (1) A step of arranging four aluminum plates in a square frame shape forming an opening inside, and arranging blocks for protecting the parent material on both sides of the boundary between the four arranged plates; (2) A step of performing friction stir welding for joining on each of the upper and lower surfaces of the boundary between the plates; (3) a step of heat treating the welded square frame; and (4) A method for manufacturing a shadow frame, comprising: a step of anodizing a square frame.

2. In paragraph 1, The above-mentioned plate is a shadow frame manufacturing method of an aluminum alloy of the 2000 series, 5000 series, 6000 series or 7000 series.

3. In paragraph 1, (1) a step of performing rough machining on the area where welding is performed in step (2) between steps (1) and (2); and (3) A method for manufacturing a shadow frame further comprising a step of cutting and processing a surface to be anodized between steps (4).

4. In paragraph 1, (2) A shadow frame manufacturing method further comprising a step of performing cosmetic friction stir welding with a tool insertion depth of less than half of the tool insertion depth of the friction stir welding for joining performed in step (2) on the welded portions formed on the upper and lower surfaces, respectively, in order to minimize surface discoloration between the welded portion and the non-welded portion between steps (3).

5. In paragraph 1, A method for manufacturing a shadow frame, wherein the above heat treatment is performed at a temperature of 200 to 600°C for 2 to 6 hours.

6. In paragraph 1, (4) A shadow frame manufacturing method that performs mixed acid anodization using sulfuric acid and hydroxide to minimize surface discoloration between welded and non-welded areas.

7. In paragraph 6, A shadow frame manufacturing method in which mixed acid anodic oxidation is performed at a voltage of 70 to 90 V for 2200 to 5000 seconds in an electrolyte containing 3 to 7 wt% of oxalic acid and 0.1 to 0.5 wt% of sulfuric acid.

8. In paragraph 1, (4) A shadow frame manufacturing method further performing one or more of the sealing and heat treatment processes after step (4).

9. According to any one of the clauses 1 to 8 The above-mentioned friction stir welding for cosmetics is a shadow frame manufacturing method performed at an insertion depth of 1 / 3 to 1 / 2 or less of the tool insertion depth of friction stir welding for joining.

10. A shadow frame manufactured by a manufacturing method according to any one of claims 1 to 9.

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