JP5458272B2 - Antifouling faceplate for display device transparent in visible light region, method for producing the same, display device and article using them - Google Patents

Description

The present invention relates to an antifouling faceplate for a display device that is transparent in the visible light range, a method for manufacturing the same, a display device using the same, and an article. More specifically, the antifouling faceplate for a display device that is highly durable and inexpensive to manufacture, is safe in the human body and the environment, and is highly visible in the visible light region, its manufacturing method, and the method thereof. The present invention relates to a display device and an article used.

In recent years, with the improvement of living standards and the enhancement of hygiene awareness, countermeasures against contamination of articles around us have been demanded. Display devices used in various information devices and operation terminals are also required to have improved antifouling properties for reasons such as improved visibility and reduced maintenance costs, particularly public health requirements for touch panels.

There are two methods for preventing contamination on the surface of the member: a method of forming a film having a small surface energy on the surface of the member and a surface treatment method of reducing the surface energy of the surface of the member itself. There are demands for a small number of technologies and manufacturing technologies that cause less environmental damage when disposing of products.

For example, in Patent Document 1, a film having a fluoroalkyl group and a siloxane bond is formed on the top surface of a float glass as a technique for forming a monomolecular film having low surface energy and resource saving on the surface of a member. There is disclosed a cooking device characterized in that glass is used as a window glass and the film surface is on the cooking side.

Patent Document 2 discloses a technique for antifouling treatment of the member surface itself using fluorine gas.

JP 10-137132 A JP-A-2005-290118

However, in the method described in Patent Document 1, when the base material that forms a film on the surface is a resin or the like that does not have an active hydrogen group on the surface, it is necessary to oxidize the surface in advance to introduce active hydrogen. Moreover, since a solvent is required at the time of film formation, it has the problem that environmental impact is large.
On the other hand, the method described in Patent Document 2 does not require a solvent at the time of film formation, but has a problem that the reaction requires a long time (several hours) and is therefore inefficient.

The present invention has been made in view of such circumstances, and has an antifouling face plate for a display device that is transparent in the visible light range and has a low environmental impact during processing and disposal and can be manufactured at low cost, and a method for manufacturing the same It is an object of the present invention to provide a display device and an article using the.

The first aspect of the present invention has a hydrocarbon group in which a part or all of hydrogen atoms are substituted with one or both of a fluorine atom and a fluorocarbon group on the outer surface of the base material, and the surface roughness. The object is achieved by providing an antifouling faceplate for a display device that is transparent in the visible light range, characterized in that the thickness is 10 nm or more and 300 nm or less .
In the present invention, the “display device” includes a touch panel for device operation having both a display function and an operation function. Furthermore, the “article” includes a mobile phone, an electronic computer, a PDA (personal digital assistant), a GPS terminal, a television receiver, a cash dispenser (CD) device, an automatic teller machine (ATM), and the like.

The “face plate” refers to a transparent plate-like member that covers the outermost surface on the display surface of the display device. A touch panel that has not only the protection of the display surface but also an input function is the “face plate” in the present invention. include. In addition, the “outer surface of the base material” refers to a surface that becomes the outer side when incorporated as a face plate in a display device.

Since the outer surface of the substrate has a hydrocarbon group in which some or all of the hydrogen atoms are substituted with either or both of fluorine atoms and fluorocarbon groups, the surface energy is reduced, and the water and oil repellency is improved. In addition to being able to improve, since it becomes difficult for organic substances or the like that cause dirt to adhere, the antifouling property can also be improved.

In the antifouling faceplate for a display device that is transparent in the visible light region according to the first aspect of the present invention, the substrate may be a resin that is transparent in the visible light region .

In the first display faceplate in accordance with aspects of the present invention, the surface roughness of the outer surface Ru der than 3 nm or less 10 nm.
When the surface roughness of the face plate is less than 400 nm , which is the shortest wavelength of visible light, high water / oil / oil repellency can be imparted without impairing the transparency of the face plate.

In the second aspect of the present invention, a resin substrate that is transparent in the visible light region is preliminarily processed by low-pressure plasma treatment in an oxygen gas atmosphere so that the surface roughness is 10 nm or more and 300 μm or less. An antifouling faceplate for a display device transparent in the visible light region, characterized in that the surface is replaced with one or both of fluorine atoms and fluorocarbon groups by low-pressure plasma treatment in a gas atmosphere of the compound containing The problem is solved by providing a manufacturing method.
Compounds containing a fluorocarbon group is a plasma processing conditions, to generate fluorine radicals (· F) or · CF ₃ and the like fluorocarbon radicals. By replacing this with a hydrogen atom of a hydrocarbon group present on the surface of the substrate, a fluorocarbon group can be introduced into the surface of the substrate without using a solvent, and the surface energy on the outer surface of the substrate can be reduced. .

In the method for manufacturing a face plate for a display device according to the second aspect of the present invention, a resin substrate transparent in the visible light region is previously subjected to low-pressure plasma treatment in an oxygen gas atmosphere so that the surface roughness is 10 nm or more and 300 μm or less. After processing, the outer surface of the substrate is further subjected to low-pressure plasma treatment in a gas atmosphere of a compound containing a fluorocarbon group.
When the outer surface of the substrate is subjected to low-pressure plasma treatment in advance in an oxygen gas atmosphere and then in a gas atmosphere containing a fluorocarbon group, a display device with high antifouling properties and high durability can be efficiently provided.

In the method for manufacturing a display device according to the second aspect of the present invention, as the compound containing the fluorocarbon group, tetrafluoromethane (CF ₄ ), hexafluoroethane (C ₂ F ₆ ), tetrafluoroethylene (C _2). One or more of F ₄ ) and trifluoromethane (CHF ₃ ) are preferably used.
Since these compounds containing a fluorocarbon group are available at a relatively low cost, the manufacturing cost of the display device can be reduced.

A third aspect of the present invention solves the above problem by providing a display device using the face plate for a display device according to the first aspect of the present invention.

A fourth aspect of the present invention solves the above problem by providing an article using the display device according to the third aspect of the present invention.

The article according to the fourth aspect of the present invention is any of a mobile phone, an electronic computer or a display device for an electronic computer, a portable information terminal, a GPS terminal, a television receiver, a cash dispenser device, and an automatic teller machine. May be.
All of these articles are used for articles that often come into contact with the human body, and antifouling properties are strongly required from the viewpoint of hygiene, and the present invention can be suitably applied.

According to the present invention, there are provided a face plate for a display device having a face plate that can be manufactured at a low cost at the time of processing and disposal, and a manufacturing method thereof, and a display device and an article using them. In addition, according to the method of the present invention, it is possible to impart a water / oil repellent / antifouling function only on the outermost surface of the face plate having a hydrocarbon group on the surface, with resource saving, energy saving and low cost.

The display device according to the present invention and an article using the display device have high antifouling properties, durability, safety for human bodies and the environment, and can exhibit antifouling properties semipermanently.

It is explanatory drawing of the cross-sectional structure of the face plate for display apparatuses which concerns on one embodiment of this invention. FIGS. 4A and 4B are explanatory views of a method for manufacturing a face plate for a display device, in which FIGS. 4A and 4B are views of the outside of the face plate before and after low-pressure plasma treatment in a gas atmosphere of a compound having a fluorocarbon group, respectively. It is explanatory drawing which expanded the surface vicinity to the molecular level, and represented typically.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

A face plate for a display device (hereinafter, may be abbreviated as “face plate”) 10 according to an embodiment of the present invention is a hydrogen atom in which some or all of hydrogen atoms are either fluorine atoms or fluorocarbon groups. An acrylic base material (hereinafter referred to as “acrylic”) in which one or both substituted hydrocarbon groups 11 (schematically shaded in FIG. 1) are hard-coated with a UV curable resin as an example of the base material. Abbreviated as “base material”). As shown in FIG. 2A, the acrylic substrate 12 is covered with hydrocarbon groups 13 on the surface. On the surface of the face plate 10 after the low-pressure plasma treatment, as shown in FIG. 2B, some of the hydrogen atoms of the hydrocarbon groups 13 covering the surface of the acrylic base material 12 before the low-pressure plasma treatment are fluorinated. The trifluoromethyl group 14 which is an example of the carbon group is substituted.

The face plate 10 is manufactured by subjecting the substrate outer surface of the acrylic substrate 12 to low-pressure plasma treatment in a gas atmosphere of a compound containing a fluorocarbon group.
When plasma is generated by high frequency discharge in a gas atmosphere of a compound containing a fluorocarbon group, a fluorocarbon radical such as a fluorine radical (· F) or a trifluoromethyl radical (· CF ₃ ) is generated. These radicals substitute the hydrogen atom of the hydrocarbon group on the surface of the acrylic substrate 12 with the trifluoromethyl group 14 (FIG. 2B). Alternatively, when a gas containing a compound having an unsaturated bond such as tetrafluoroethylene is used, a perfluoroalkyl group having a large carbon number can also be generated by plasma polymerization.

For the low-pressure plasma treatment, any plasma treatment apparatus that can be used for plasma surface treatment or low-temperature ashing can be used. Specific examples of the form of the chamber include a flow tube type, a bell jar type, etc., and as a form of the electrode for discharge, a parallel plate type, a coaxial cylindrical type, a curved counter plate type such as a cylinder, a sphere, etc. Examples include a hyperboloid opposed flat plate type and a plurality of fine wire opposed flat plate types. The high frequency current can be applied by either a capacitive coupling method or an induction method using an external electrode. The output of the high-frequency power source is appropriately adjusted depending on the material and size of the base material, the type of compound containing a fluorocarbon group used, the type and volume fraction of the added gas, the volume and pressure of the chamber, etc. For example, 10 to 250 W.

Examples of the compound containing a fluorocarbon group that has been confirmed to be usable include CF ₄ , C ₂ F ₆ , C ₂ F ₄ , and CHF ₃ . In principle, even a compound that contains a CF ₃ group and is liquid at normal temperature and pressure can be used as long as it can be gasified under low-pressure plasma processing conditions. At this time, if a trace amount (0.1 to 5% by volume) of Ar, He or the like is mixed, there is an effect of stabilizing the discharge.

Further, if a small amount of oxygen (0.1 to 15% by volume) is contained, the resin surface is replaced with a CF ₃ group while oxidizing the resin surface, which has an effect of increasing the processing efficiency. Alternatively, low-pressure plasma treatment may be performed in a gas atmosphere of a compound containing a fluorocarbon group after performing low-pressure plasma treatment in an oxygen gas atmosphere in advance and performing surface oxidation etching.

In this embodiment, the acrylic substrate 12 hard-coated with a UV curable resin has been described as an example of the substrate. However, the substrate has a resin containing a hydrocarbon group on the surface. Anything can be used. The resin present on the surface of the substrate may have a function as a surface protective film, a polarizing filter, or the like. Moreover, when using as a touch panel, thickness may be made small so that it may have flexibility, and you may have transparent conductor layers, such as ITO, on the back side. Or what adhered these resin on the outer surface of transparent base materials, such as glass, may be used as a base material.

Specific examples of the resin include polyurethane, polyester, polyethylene, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, polyvinylidene chloride, polyvinyl chloride, polyolefin, polycarbonate, polyvinyl acetate, polystyrene, polysulfone, polytrimethylene terephthalate, poly Lactic acid, polyvinyl alcohol, polyvinyl pyrrolidone, polybutylene terephthalate, polybutylene naphthalate, polyvinylidene fluoride, polypropylene, polymer alloy, polymethylpentene, ionomer resin, acrylic resin, acetyl cellulose, alkyd resin, AS resin, liquid crystal polymer, ethylene propylene Examples include rubber, ABS resin, epoxy resin, urea resin, and other engineering plastics. It is.

The surface roughness of the outer surface of the face plate 10 is not less than 10 nm and not more than 900 μm. The shape of the irregularities on the surface of the face plate 10 is not particularly limited as long as it does not impair the optical characteristics of the acrylic substrate 12 due to diffraction of incident light, irregular reflection, etc. Even if it is a regular shape, it is an irregular shape. May be. In general, when the surface roughness is within the above range, the hydrophobicity of the surface after the low-pressure plasma treatment can be further improved without deteriorating the surface characteristics of the acrylic substrate 12. The surface roughness of the acrylic substrate 12 is preferably 400 nm or less, which is the shortest wavelength of visible light, more preferably 360 nm or less, and even more preferably 300 nm or less. If the surface roughness is within the above range, the optical properties of visible light such as transparency of the acrylic substrate 12 are not impaired. The surface roughness can be measured using any known method such as a surface roughness meter or a three-dimensional measuring instrument. Further, the size of the unevenness can be measured by image analysis using a stereoscopic microscope or an electron micrograph.

As a method for roughening the outer surface of the acrylic substrate 12 so as to have a surface roughness and an unevenness size within the above ranges, sand blasting, mechanical polishing, chromic acid mixture, phosphoric acid, alkali, etc. The surface may be roughened in advance using any known method such as treatment, but when performing low-pressure plasma treatment in an atmosphere containing oxygen gas, the surface has a desired surface roughness and unevenness. The plasma treatment conditions may be adjusted as appropriate to obtain the above.

Examples of the display device using the face plate 10 include a CRT (cathode ray tube, cathode ray tube), a liquid crystal display device, a plasma display, an organic and inorganic EL display device, and the like.
Articles using a display device incorporating the face plate 10 include a mobile phone, an electronic desk calculator, an electronic computer or a display for an electronic computer, a PDA (personal digital assistant), a portable game machine, a portable GPS terminal, a car navigation system, Examples include a television receiver, a portable DVD player, a digital camera, a video recording device, a cash dispenser (CD) device, an automatic teller machine (ATM), and an automatic ticket machine.

Examples carried out for confirming the features and effects of the present invention will be described below.
Example 1: Manufacture of a face plate for a display device using a transparent acrylic resin substrate as a base material First, a transparent acrylic resin substrate having an ultraviolet curable hard coat film formed on the outermost surface was washed with ethanol, and then the conditions shown in Table 1 Under (Condition 1), low-pressure plasma treatment (O ₂ plasma treatment) in an oxygen gas atmosphere was performed. Next, plasma treatment was performed in a tetrafluoromethane (CF ₄ ) atmosphere containing oxygen under the conditions shown in Table 2 (Condition 2). In Tables 1 and 2, sccm used as a unit of flow rate is a non-SI unit, and 1 sccm = 1.69 × 10 ⁻⁴ Pa · m ³ / sec.

The water droplet contact angle of the face plate thus obtained was measured. The measurement was performed at five different points (I to V) on the same sample. The measurement results are as shown in Table 3 below. In Table 3, “CA” means a contact angle, and “Avg.” And “SD” mean an average value and a standard deviation, respectively. The water droplet contact angle of the acrylic resin substrate before treatment was 75.0 degrees.

A significant increase in water droplet contact angle was observed for all samples. This is because, as shown in FIG. 2B, the hydrocarbon group on the surface of the acrylic resin substrate reacts with the .CF ₃ radical generated in the plasma, and the hydrogen atom is replaced with the —CF ₃ group. It is thought that the surface water repellency was improved by bonding a large number of CF ₃ groups.

Here, the O ₂ plasma treatment has an action of cleaning the surface of the acrylic resin substrate and an action of roughening the surface of the member, and the surface roughness can be controlled by arbitrarily controlling the power of the high frequency power source and the treatment time. Can be controlled within a range of several nanometers to several hundred microns, and the final water droplet contact angle can be controlled to about 165 to 100 degrees. In particular, if the water droplet contact angle was controlled to be 150 degrees or more, a high-performance oil-repellent and antifouling member with extremely low surface energy could be produced. Further, when the surface roughness was set to be equal to or less than the wavelength of visible light (for example, 400 nm), the transparency of the acrylic resin substrate used as the base material was not impaired.

In addition to CF ₄ , compounds containing CF ₂ groups or CF ₃ groups such as C ₂ F ₆ , C ₂ F ₄ , and CHF ₃ could be used similarly.

Example 2: Production of face plate for display device based on transparent polyethylene terephthalate resin substrate As in Example 1, first, a transparent PET (polyethylene terephthalate) resin substrate was washed with ethanol, and then the conditions shown in Table 1 Under (Condition 1), O ₂ plasma treatment was performed. Next, conditions similar to those shown in Table 2 were used except that hexafluoroethane (C ₂ F ₆ ) was used as the compound containing a fluorocarbon group, the power of the high-frequency power source was 250 W, and the treatment time was 5 minutes. Then, low-pressure plasma treatment was performed. Then, when the contact angle was measured, the water droplet contact angle of the sample was 147 degrees.
In addition, even when other compounds containing a fluorocarbon group were used, it was confirmed that the same effect was obtained if a CF ₂ group or a CF ₃ group was included.

The article to which the present invention can be applied may be in any form as long as it is a display device. Specifically, it can be used for a mobile phone, an electronic computer, a PDA, a GPS, a television receiver, a cash dispenser (CD) device, a display device installed in an ATM device, or a member used for them. .

10: Face plate 11 for display device 11: Hydrocarbon group in which part or all of hydrogen atoms are substituted with one or both of fluorine atom and fluorocarbon group 12: Acrylic hard-coated with UV curable resin Base material 13: Hydrocarbon group 14: Trifluoromethyl group

Claims (7)

It has a hydrocarbon group in which some or all of the hydrogen atoms are substituted with one or both of a fluorine atom and a fluorocarbon group on the outer surface of the substrate, and the surface roughness is 10 nm or more and 300 nm or less. An antifouling faceplate for display devices that is transparent in the visible light range . Transparent display device antifouling faceplate in the visible light region according to claim 1, wherein said substrate is a transparent resin in the visible light region.
A resin substrate that is transparent in the visible light region is preliminarily processed with low pressure plasma in an oxygen gas atmosphere to have a surface roughness of 10 nm to 300 μm , and then low pressure plasma in a gas atmosphere of a compound containing a fluorocarbon group. A method for producing an antifouling faceplate for a display device that is transparent in the visible light region, wherein the surface is replaced with one or both of fluorine atoms and fluorocarbon groups after treatment. As the compound containing the fluorocarbon _{group, CF 4, C 2 F 6} , C 2 F 4, and a transparent display in the visible light region according to claim 3, which comprises using one or more of CHF ₃ A method for producing an antifouling faceplate for an apparatus. A display device using the antifouling faceplate for a display device according to claim 1 or 2 . An article using the display device according to claim 5 . Wherein the article, a cellular phone, a display device an electronic calculator or computer, portable information terminal, GPS terminal, a television receiver, according to claim, characterized in that either a cash dispenser device, and automated teller machines 6 The article described.

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