Input device cover member and input device

Abstract

To provide a cover member for an input device capable of achieving an excellent writing feeling in an input operation to the input device, and the input device.SOLUTION: The glass board 20 as the cover member for the input apparatus arranged on the front side of a display device 30 in the input apparatus 10 has an uneven shape on at least one main surface 20a of the glass board 20, and the maximum valley depth Rv of roughness curve elements on the main surface 20a having the uneven shape is larger than the maximum peak height Rp of the roughness curve elements.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cover member for an input device and an input device. [Background technology]

[0002] 2. Description of the Related Art Pen input devices have been known in the past that allow a user to input characters, figures, and the like by handwriting on a screen using an input pen.

[0003] In such a pen input device, a transparent cover member made of a glass substrate or the like is placed on the front side of a display device such as an LCD display, and various input operations can be performed by touching and moving the input pen on the surface of the cover member.

[0004] Here, when a glass substrate is used as the cover member of a pen input device, the surface of the glass substrate is generally formed smoothly with small irregularities, so when an input pen is brought into contact with the surface of the cover member (glass substrate) and moved, the tip of the input pen slips, resulting in an uncomfortable writing experience.

[0005] Therefore, in order to prevent the input pen from slipping easily, Patent Document 1 discloses using a pen tip made of an elastomer material having a high coefficient of friction. Furthermore, Patent Document 2 discloses a cover glass (cover member) in which the writing comfort is improved by increasing frictional force through the application of minute irregularities to the glass surface by etching. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-173955 [Patent Document 2] International Publication No. 2015 / 072297 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when a pen tip made of an elastomer material as described in Patent Document 1 is used, the flexibility of the pen tip improves the writing feel, but the elastomer material has a strong adhesive force to the cover member, making the pen tip too difficult to slide, and when the input pen is brought into contact with the surface of the cover member and moved, the writing feel can actually become worse. Furthermore, even when a pen tip made of an elastomer material with a high adhesive force is used for the cover glass described in Patent Document 2, when the input pen is repeatedly brought into contact with the surface of the cover glass and moved, the friction force between the pen tip and the cover glass becomes too high, making it difficult to achieve a good writing feel.

[0008] The present invention has been made in consideration of the current problems described above, and provides a cover member for an input device, and an input device, which can achieve an excellent writing feel when operating an input device, even when a material with a high friction coefficient, such as an elastomer material, is used for the pen tip. [Means for solving the problem]

[0009] The cover member for an input device and the input device that solve the above problems have the following features.

[0010] That is, the cover member for an input device according to the present invention is a cover member for an input device that is placed on the front side of a display device in an input device, and is characterized in that at least one of the main surfaces of the cover member for an input device has an uneven shape, and the maximum valley depth Rv of the roughness curve element on the main surface having the uneven shape is greater than the maximum peak height Rp of the roughness curve element. By having such a configuration, the cover member for an input device according to the present invention has deep valleys in the uneven shape of the main surface, which reduces the contact area with the pen tip, thereby suppressing an excessive increase in frictional force between the main surface and the pen tip, and achieving an excellent writing feel when performing input operations on the input device.

[0011] In the cover member for an input device according to the present invention, it is preferable that the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa on the main surface having the uneven shape is 6 or more. By having such a configuration, the cover member for an input device according to the present invention suppresses an excessive increase in frictional force between the main surface and the pen tip, thereby realizing an excellent writing feel when performing input operations on the input device.

[0012] In the cover member for an input device according to the present invention, it is preferable that the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa on the main surface having the uneven shape is 15 or more. By having such a configuration, the cover member for an input device according to the present invention can further suppress an excessive increase in frictional force between the main surface and the pen tip, thereby achieving an even better writing feel when performing input operations on the input device.

[0013] Furthermore, in the cover member for an input device according to the present invention, it is preferable that the ratio Rv / RSm of the maximum valley depth Rv of the roughness curve element to the average length RSm of the roughness curve element on the main surface having the uneven shape is 0.001 or more and 0.1 or less. By having such a configuration, the cover member for an input device according to the present invention can make the pen tip slide appropriately easily on the main surface, thereby realizing an excellent writing feel when performing input operations on the input device.

[0014] In the cover member for an input device according to the present invention, it is preferable that the arithmetic mean height Sa of the main surface having the irregular shape is 1 nm or more and 50 nm or less. By having such a configuration, the cover member for an input device according to the present invention can appropriately prevent the pen tip from slipping on the main surface and appropriately reduce the difficulty of the pen tip slipping on the main surface, thereby providing an excellent writing feel with the input pen when performing input operations on the input device.

[0015] An input device according to the present invention comprises any of the above-described cover members for an input device, a display device, and a detection circuit for detecting pen input. The input device according to the present invention is characterized by including an input pen that performs pen input to the input device by moving while in contact with the main surface of the input device cover member. With this configuration, the input device according to the present invention can provide an excellent writing feel when performing an input operation on the input device using an input pen. [Effects of the Invention]

[0016] According to the present invention, an excellent writing feel can be achieved when performing an input operation on an input device. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic side cross-sectional view showing the input device. [Figure 2] FIG. 10 is a diagram showing a measured cross-sectional curve on a main surface of a cover member. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, an embodiment of an input device cover member and an input device according to the present invention will be described with reference to the accompanying drawings.

[0019] [Overall Configuration of Pen Input Device 10] First, the overall configuration of the input device 10 will be described with reference to FIG. The input device 10 is one embodiment of an input device equipped with a cover member for an input device according to the present invention. The input device 10 includes a display element 30, which is an example of a display device that displays images, a glass substrate 20 as a cover member arranged on the front side of the display element 30, a digitizer circuit 40 arranged on the back side of the display element 30, and an input pen 50. The glass substrate 20 is an example of a cover member for an input device according to the present invention, and the digitizer circuit 40 is an example of a detection circuit for detecting an input according to the present invention.

[0020] In the above description, the "front side" of the display element 30 means the side on which an image is displayed, and the "rear side" of the display element 30 means the side opposite to the side on which an image is displayed. In this embodiment, for example, the "front side" of the display element 30 is the upper side of the paper in FIG. 1, and the "rear side" of the display element 30 is the lower side of the paper in FIG.

[0021] The input device 10 is configured to enable pen input (input operation) of characters, figures, etc. by moving an input pen 50 in contact with a main surface 20a of the glass substrate 20 (the surface of the glass substrate 20 opposite to the display element 30 side). An example of the input device 10 is a tablet terminal.

[0022] Here, the tablet terminal broadly refers to a display device for pen input that has both a display function and a pen input function, and includes devices such as tablet PCs, mobile PCs, smartphones, and game consoles.

[0023] The glass substrate 20 is formed of a transparent glass plate having an uneven shape formed on at least one of its main surfaces (the main surface 20a in this embodiment). The glass substrate 20 is arranged so that the main surface 20a on which the concave and convex shapes are formed is the surface that comes into contact with the input pen 50.

[0024] Here, the glass substrate 20 may be a glass plate made of, for example, aluminosilicate glass or borosilicate glass. Furthermore, when the glass substrate 20 is made of a glass plate made of alkali-containing aluminosilicate glass, the glass substrate 20 may have a chemically strengthened layer on the surface thereof. The glass substrate 20 will be described in detail later.

[0025] The digitizer circuit 40 includes a detection sensor that detects an input operation by the input pen 50 . The input pen 50 is an input device shaped like a writing implement such as a pencil or ballpoint pen, and has a pen tip 51, which is an example of a friction element that comes into contact with the glass substrate 20, and the pen tip 51 is made of a synthetic resin material such as elastomer or polyacetal resin, or felt.

[0026] In the input pen 50, if the pen tip 51 is made of the above-mentioned material, it can easily catch on even minute uneven shapes. Therefore, when the pen tip 51 of the input pen 50 is moved in contact with the main surface 20a of the glass substrate 20 on which the concave-convex shape is formed, a particularly excellent writing feel can be realized.

[0027] In this embodiment, a glass substrate 20 is used as the cover member for the input device, but this is not limited to this. For example, a resin substrate made of synthetic resin and having an uneven shape formed on at least one of its main surfaces can also be used as the cover member for the input device. In this case, the uneven shape of the resin substrate can be formed, for example, by subjecting the main surface of the resin substrate to blasting such as wet blasting, or by subjecting the main surface of the resin substrate to embossing.

[0028] It is also possible to use a resin layer having an uneven surface formed on at least one main surface of a glass substrate as a cover member for an input device. In this case, the cover member can be constructed by attaching a resin sheet having an uneven surface to the main surface of the glass substrate.

[0029] The uneven shape of the resin sheet can be formed, for example, by embossing the surface of the resin sheet or by forming a synthetic resin mixed with powder into a sheet shape. In addition, the resin layer can also be formed by spraying a synthetic resin onto the main surface of the glass substrate.

[0030] However, when the glass substrate 20 is used as the cover member for the input device, compared with the case of using the above-mentioned resin substrate or the one with a resin layer formed on the main surface of the glass substrate, the hardness of the surface (especially the main surface that comes into contact with the pen tip 51 of the input pen 50) is higher, so it is advantageous in that the surface is less likely to be scratched.

[0031] [Configuration of Glass Substrate 20] Next, the configuration of the glass substrate 20 will be described in detail with reference to FIGS. 1 and 2. As described above, the glass substrate 20 is an embodiment of the cover member for the input device according to the present invention. In FIG. 1, an uneven shape is formed on the main surface 20a of the glass substrate 20.

[0032] As shown in FIG. 2, the uneven shape formed on the main surface 20a of the glass substrate 20 is composed of minute unevenness having irregularly deep valleys. In the minute unevenness of the main surface 20a, the maximum valley depth Rv of the roughness curve element is larger than the maximum peak height Rp of the roughness curve element (Rp < Rv). Also, in the minute unevenness of the main surface 20a, the arithmetic mean height Sa is 1 nm or more and 50 nm or less.

[0033] Furthermore, in the minute unevenness of the main surface 20a, the ratio Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 6 or more (Sv / Sa ≥ 6). In this case, it is preferable that the ratio Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 15 or more (Sv / Sa ≥ 15). Also, in the minute unevenness of the main surface 20a, the ratio Rv / RSm, which is the ratio of the maximum valley depth Rv of the roughness curve element to the average length RSm of the roughness curve element, is 0.001 or more and 0.1 or less (0.001 ≤ Rv / RSm ≤ 0.1).

[0034] Here, the maximum valley depth Rv, maximum peak height Rp, and average length RSm of the roughness curve element in this application conform to JIS B0601 2013, and the arithmetic mean height Sa and maximum valley depth Sv conform to ISO 25178.

[0035] The arithmetic mean height Sa of the minute irregularities on the main surface 20a is the average of the absolute values ​​of the height Za of the peaks and the depth Zb of the valleys of the irregularities on a given surface (Sa = (|Za1| + |Za2| + + |Za n |)+(|Zb1|+|Zb2|+···+|Zb n |)) / 2n). The maximum valley depth Sv is the deepest valley Sv of the micro-irregularities on a given surface.

[0036] Furthermore, the maximum peak height Rp of the minute irregularities is the height Rp of the highest peak of the minute irregularities in a predetermined reference length, and the maximum valley depth Rv of the minute irregularities is the depth Rv of the deepest valley of the minute irregularities in a predetermined reference length. The sum of the maximum peak height Rp and the maximum valley depth Rv in a predetermined specified length is the maximum height Rz (Rz = Rp + Rv). Furthermore, the average length RSm of the roughness curve elements of the minute irregularities is the average of the respective period lengths X of the minute irregularities in a predetermined reference length (RSm = (X1 + X2 + ... + X n ) / n).

[0037] The values ​​of the arithmetic mean height Sa, maximum valley depth Sv, maximum height Rz of the roughness curve element, average length RSm of the roughness curve element, maximum peak height Rp of the roughness curve element, and maximum valley depth Rv of the roughness curve element in the above-mentioned minute irregularities are values ​​evaluated from a roughness curve obtained when the cutoff value λc1 of the high-pass filter λc for cutting off long wavelength components from the measured cross-sectional curve of the main surface 20a is set to 14 μm, and the cutoff value λs1 of the low-pass filter λs for cutting off short wavelength components from the measured cross-sectional curve of the main surface 20a is set to 0.35 μm.

[0038] That is, when the cut-off value λc1 of the high-pass filter λc is 14 μm and the cut-off value λs1 of the low-pass filter λs is 0.35 μm, the concavo-convex shape formed on the main surface 20a of the glass substrate 20 appears as minute concavo-convex with a relationship of Rp < Rv between the maximum valley depth Rv and the maximum peak height Rp, appears as minute concavo-convex with an arithmetic mean height Sa of 1 nm or more and 50 nm or less, appears as minute concavo-convex with a ratio of Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, of 6 or more, and appears as minute concavo-convex with a ratio of Rv / RSm, which is the ratio of the maximum valley depth Rv of the roughness curve element to the average length RSm of the roughness curve element, of 0.001 or more and 0.1 or less.

[0039] Thus, the concavo-convex shape formed on the main surface 20a of the glass substrate 20 is composed of minute concavo-convex having irregularly deep valleys.

[0040] In the input device 10 (see FIG. 1) in the present embodiment, since the shape of the minute concavo-convex on the main surface 20a of the glass substrate 20 is formed within the range of the above-described conditions, it is possible to improve the writing feeling of the input pen 50 while maintaining the visibility of the display element 30 (also see FIG. 1). Further, by forming such minute concavo-convex into a concavo-convex shape configured within the range of the above-described conditions, it is possible to suppress the occurrence of glittering called sparking due to the interference of scattered light by the concavo-convex shape. Furthermore, in the present embodiment, since no resin layer is formed on the main surface 20a of the glass substrate 20 and the concavo-convex shape is directly formed on the main surface 20a, the damage resistance is high and it is difficult to be scratched, so the visibility of the display element 30 is not deteriorated.

[0041] The minute concavo-convex contributes to the frictional force between the main surface 20a of the glass substrate 20 and the pen tip 51 of the input pen 50. Further, the contribution of the frictional force changes depending on the material of the pen tip 51.

[0042] Specifically, in the case of a pen tip 51 made of elastomer, which is a material with a low elastic modulus, the flatter the main surface 20a of the glass substrate 20, the greater the frictional force generated by adhesion, making it more difficult for the pen tip 51 to slide against the main surface 20a of the glass substrate 20. In this case, by providing minute irregularities on the main surface 20a of the glass substrate 20, the contact area between the main surface 20a and the pen tip 51 of the input pen 50 can be reduced, making it possible to make the pen tip 51 slide appropriately easily over the main surface 20a of the glass substrate 20.

[0043] On the other hand, in the case of the pen tip 51 made of a hard material such as POM, the flatter the main surface 20a of the glass substrate 20, the lower the frictional force becomes, and the easier it is for the pen tip 51 to slide on the main surface 20a of the glass substrate 20. To address this issue, by providing minute irregularities on the main surface 20a of the glass substrate 20, it is possible to make it easier for the pen tip 51 of the input pen 50 to catch on the main surface 20a. This increases the frictional force between the main surface 20a and the pen tip 51, making it appropriately difficult for the pen tip 51 to slip on the main surface 20a of the glass substrate 20.

[0044] Note that the pen tip 51 made of a material such as felt behaves similarly to the above-mentioned POM pen tip 51, and by providing minute irregularities on the main surface 20a of the glass substrate 20, the pen tip 51 of the input pen 50 becomes more likely to catch on the main surface 20a. This increases the frictional force between the main surface 20a and the pen tip 51, making it possible to make the pen tip 51 suitably less likely to slip on the main surface 20a of the glass substrate 20.

[0045] In this way, by providing minute irregularities on the main surface 20a of the glass substrate 20, it is possible to appropriately prevent the pen tip 51 of the input pen 50 made of various materials (elastomer, POM, and felt) from slipping on the main surface 20a, or to appropriately reduce the difficulty of the pen tip 51 to slip on the main surface 20a. This makes it possible to improve the writing comfort with the input pen 50 when performing input operations on the input device 10.

[0046] In particular, by imparting minute irregularities with an arithmetic mean height Sa of 1 nm or more and 50 nm or less to the main surface 20a of the glass substrate 20, sliding of the pen tip 51 on the main surface 20a can be moderately suppressed, and the slipperiness of the pen tip 51 on the main surface 20a can be moderately reduced, thereby making the writing feel by the input pen 50 excellent in the input operation to the input device 10.

[0047] Here, as described above, in the present embodiment, the upper limit value of the arithmetic mean height Sa of the minute irregularities is set to 50 nm, but the upper limit value is preferably set to 40 nm, more preferably set to 30 nm, particularly preferably set to 20 nm, and most preferably set to 15 nm.

[0048] Also, as described above, in the present embodiment, the minute irregularities on the main surface 20a have deep valleys, and the maximum valley depth Rv and the maximum peak height Rp have a relationship of Rp < Rv. The peaks of the minute irregularities on the main surface 20a catch on the pen tip 51, contributing to an increase in the frictional force. On the other hand, the valleys of the minute irregularities on the main surface 20a do not contact the pen tip 51, that is, contributing to a reduction in the contact area. Minute irregularities having irregularly deep valleys have a surface shape as shown in FIG. 2, and due to the presence of deep valleys, the contact area with the pen tip 51 is reduced, and as a result, an excessive increase in the frictional force can be suppressed. In particular, the pen tip 51 made of an elastomer with strong adhesion contributes to a reduction in the frictional force, and the sliding of the pen tip 51 becomes smooth. Thereby, an excellent writing feel can be realized in the input operation to the input device 10.

[0049] Here, as described above, in the present embodiment, the maximum valley depth Rv and the maximum peak height Rp have a relationship of Rp < Rv, but preferably have a relationship of Rv - Ra ≧ 0.5, more preferably have a relationship of Rv - Ra ≧ 1, particularly preferably have a relationship of Rv - Ra ≧ 2, and most preferably have a relationship of Rv - Ra ≧ 3.

[0050] Furthermore, as described above, in this embodiment, the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa is set to be 6 or more, but it is preferable to set Sv / Sa to be 8 or more, more preferably to be set to be 10 or more, even more preferably to be set to be 12 or more, and particularly preferably to be set to be 15 or more.

[0051] When Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 6 or more, this is an indicator that the micro-irregular surface has deep valleys. Therefore, when Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 6 or more, an excessive increase in frictional force between the main surface 20a and the pen tip 51 is suppressed, making it possible to achieve an excellent writing feel when performing input operations on the input device 10. In particular, when Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 15 or more, an excessive increase in frictional force between the main surface 20a and the pen tip 51 is further suppressed, making it possible to achieve an even more excellent writing feel when performing input operations on the input device 10.

[0052] Rv / RSm, which is the ratio of the average length RSm of the roughness curve elements of the minute irregularities to the maximum valley depth Rv of the roughness curve elements, is a value corresponding to the virtual aspect ratio of the valleys of the minute irregularities formed on the main surface 20a of the glass substrate 20.

[0053] Specifically, the larger the value of Rv / RSm, which is the ratio of the average length RSm of the roughness curve element to the maximum valley depth Rv of the roughness curve element, the deeper the valleys. When the valleys of the minute irregularities are deeper, in the case of a pen tip 51 made of an elastomer, which has a high adhesive force, the contact area with the main surface 20a of the glass substrate 20 can be reduced, the frictional force between the main surface 20a and the pen tip 51 can be reduced, and the pen tip 51 can be made to slide appropriately easily against the main surface 20a. This allows for an excellent writing feel when inputting data to the input device 10.

[0054] Furthermore, when the valleys of the minute irregularities are deep, in the case of a pen tip 51 made of a hard material such as POM, an increase in frictional force due to excessive catching of the pen tip 51 on the minute irregularities of the main surface 20a can be suppressed, and the pen tip 51 can be made to slide appropriately easily on the main surface 20a. This makes it possible to achieve an excellent writing feel when performing input operations on the input device 10.

[0055] As described above, in this embodiment, the lower limit value of Rv / RSm, which is the ratio of the average length RSm of the roughness curve element to the maximum valley depth Rv of the roughness curve element, is set to 0.001, but the lower limit value is preferably set to 0.002, and more preferably to 0.003.

[0056] On the other hand, if the value of Rv / RSm, which is the ratio of the average length RSm of the roughness curve element to the maximum valley depth Rv of the roughness curve element, is too large, the valley shape of the minute irregularities will become too sharp locally, making it easier for the pen tip 51, which acts as a friction element, to dig into them, and excessive frictional force will be generated between the main surface 20a and the pen tip 51, resulting in a deterioration in the writing comfort. Therefore, in this embodiment, the upper limit value of Rv / RSm, which is the ratio of the average length RSm of the roughness curve elements of the minute irregularities to the maximum valley depth Rv of the roughness curve elements, is set to 0.1, but the upper limit value is preferably set to 0.09, more preferably to 0.08, even more preferably to 0.06, and particularly preferably to 0.04.

[0057] Furthermore, the main surface 20a of the glass substrate 20 provides a particularly excellent writing feel for the pen tip 51, which is made of a material capable of adjusting the frictional force against unevenness, such as the above-mentioned elastomer and synthetic resin material such as POM, felt, and a composite material of felt and synthetic resin material.

[0058] In FIG. 1, from the viewpoint of image visibility when viewing an image on a display element 30 through the glass substrate 20, it is preferable that the haze, which is an index relating to transparency and represents the degree of cloudiness, is less than 10% in the wavelength range of visible light (380 nm to 780 nm). By setting the haze of the glass substrate 20 to less than 10%, the transparency of the glass substrate 20 can be maintained, and the visibility of the display element 30 can be maintained.

[0059] In addition, an anti-reflection film can be formed on the main surface 20a of the glass substrate 20 to reduce the reflectivity on the side that comes into contact with the input pen 50, or an anti-fouling film can be formed to prevent fingerprints from adhering and to impart water and oil repellency.

[0060] When the glass substrate 20 is used as a cover member of the input device 10, the above-mentioned anti-reflection film is formed at least on the main surface 20a on the front side (the side that comes into contact with the input pen 50) of the glass substrate 20. Furthermore, when there is a gap between the glass substrate 20 and the display element 30, it is preferable that the glass substrate 20 also has an anti-reflection film on the main surface 20b on the back side (the display element 30 side).

[0061] The anti-reflection film may be, for example, a low-refractive index film having a refractive index lower than that of the glass substrate 20, or a dielectric multilayer film in which low-refractive index films having a relatively low refractive index and high-refractive index films having a relatively high refractive index are alternately stacked. The anti-reflection film may be formed by a sputtering method, a CVD method, or the like.

[0062] When the main surface 20a of the glass substrate 20 has an anti-reflection film, the uneven shape of the main surface 20a of the glass substrate 20 is formed so that the unevenness of the surface of the anti-reflection film falls within the above-mentioned surface roughness range (values ​​of the arithmetic mean height Sa of the minute unevenness, the maximum valley depth Sv, the maximum height Rz of the roughness curve element, the average length RSm of the roughness curve element, the maximum peak height Rp of the roughness curve element, and the maximum valley depth Rv of the roughness curve element). Furthermore, when the main surface 20a of the glass substrate 20 has an anti-reflection film, the concave and convex shape of the main surface 20a of the glass substrate 20 is formed so that the haze of the glass substrate 20 having the anti-reflection film falls within the above-mentioned range.

[0063] If the arithmetic mean height Sa of the minute irregularities, the maximum valley depth Sv, the maximum height Rz of the roughness curve elements, the average length RSm of the roughness curve elements, the maximum peak height Rp of the roughness curve elements, and the maximum valley depth Rv of the roughness curve elements are measured after forming the anti-reflection coating, a 10 nm Au film is formed first, and then these values ​​are measured.

[0064] When the glass substrate 20 is used as a cover member for the input device 10, the anti-fouling film is formed on the main surface 20a on the front side (the side that comes into contact with the input pen 50) of the glass substrate 20. In addition, the anti-fouling film preferably contains a fluorine-containing polymer that contains silicon in the main chain.

[0065] The fluorine-containing polymer may be, for example, a polymer having an -Si-O-Si- unit in the main chain and a water-repellent functional group containing fluorine in the side chain. The fluorine-containing polymer can be synthesized, for example, by dehydration condensation of silanol.

[0066] When an antireflection film and an antifouling film are formed on the front main surface 20a of the glass substrate 20, the antireflection film is formed on the main surface 20a of the glass substrate 20, and the antifouling film is formed on the antireflection film.

[0067] When the main surface 20a of the glass substrate 20 has an anti-fouling film, or when the main surface 20a of the glass substrate 20 has an anti-reflection film and an anti-fouling film, the uneven shape of the main surface 20a of the glass substrate 20 is formed so that the unevenness of the surface of the anti-fouling film falls within the above-mentioned surface roughness range (arithmetic mean height Sa of minute unevenness, maximum valley depth Sv, maximum height Rz of roughness curve elements, average length RSm of roughness curve elements, maximum peak height Rp of roughness curve elements, maximum valley depth Rv of roughness curve elements). Furthermore, when the main surface 20a of the glass substrate 20 has an antifouling film, or when the main surface 20a of the glass substrate 20 has an antireflection film and an antifouling film, the uneven shape of the main surface 20a of the glass substrate 20 is formed so that the haze of the glass substrate 20 after the antifouling film is formed, or the haze of the glass substrate 20 after the antireflection film and the antifouling film are formed, falls within the above-mentioned range.

[0068] When a chemically strengthened layer is formed on the surface of the glass substrate 20, the glass substrate 20 is subjected to a chemical strengthening treatment. Chemical strengthening is a general term for a technique in which a glass substrate is immersed in a molten salt containing an alkali metal and the small alkali metal ions present on the outermost surface of the glass substrate are replaced with larger alkali metal ions present in the molten salt. On the surface of a chemically strengthened glass substrate, atoms of alkali metal ions with larger atomic diameters than the original atoms are arranged. For example, if a glass substrate contains sodium (Na), the sodium is replaced with potassium (K) in the molten salt (e.g., nitrate) during the chemical strengthening process. This allows a compressive stress layer to form on the surface of the glass substrate, thereby improving the strength of the glass substrate.

[0069] Therefore, by subjecting the glass substrate 20 to chemical strengthening treatment, the durability of the pen input device 10 itself can be improved, and the scratch resistance of the glass substrate 20 as a cover member can be improved.

[0070] [Method of manufacturing glass substrate 20] Next, a method for manufacturing the glass substrate 20 will be described with reference to FIG. The irregularities formed on at least one of the main surfaces 20a of the glass substrate 20 are formed by subjecting the main surface 20a to at least one of a sandblasting process, a wet blasting process, and the like, in combination.

[0071] Sandblasting is a process in which solid particles such as alumina are sprayed at high speed from a spray nozzle using compressed air onto a workpiece made of glass, thereby forming fine irregularities on the workpiece.In contrast, wet blasting is a process in which abrasive grains made of solid particles such as alumina and a liquid such as water are uniformly stirred to form a slurry, which is then sprayed at high speed from a spray nozzle using compressed air onto the workpiece made of glass, thereby forming fine irregularities on the workpiece.

[0072] In both sandblasting and wet blasting, when abrasive particles are sprayed at high speed and collide with the workpiece, the abrasive particles in the slurry scrape, hit, and rub the surface of the workpiece, forming fine irregularities on the surface of the workpiece. In this case, the size of the abrasive particles sprayed onto the workpiece is important; for example, by using fine abrasive particles such as #4000, #6000, or #8000, minute irregularities can be formed.

[0073] The surface roughness of the minute irregularities formed on the main surface of the workpiece by sandblasting and wet blasting (arithmetic mean height Sa, maximum valley depth Sv, maximum height Rz of the roughness curve element, average length RSm of the roughness curve element, maximum peak height Rp of the roughness curve element, maximum valley depth Rv of the roughness curve element) can be adjusted mainly by the particle size distribution of the abrasive grains sprayed and the spray pressure when spraying the slurry onto the workpiece.

[0074] In sandblasting and wet blasting, abrasive grains are sprayed onto the workpiece at high speed, causing the corners of the abrasive grains to pierce the workpiece, resulting in the formation of deep valleys in the workpiece. [Example]

[0075] Next, an example of a glass substrate 20 having a concave-convex shape formed on one main surface 20a by sandblasting or wet blasting will be described. The configuration of the glass substrate 20 is not limited to the one shown below.

[0076] [Sample preparation] In this example, Samples 1 to 13 were prepared as examples of the glass substrate 20, and Samples 14 to 18 were prepared as comparative examples for these examples, as shown in Table 1. The glass substrate 20 used for Samples 1 to 18 was made of alkali-containing aluminosilicate glass having a thickness of 0.55 mm.

[0077] [Table 1]

[0078] The glass substrate 20 of each of Samples 1 to 9 serving as examples was subjected to sandblasting to form an uneven shape on one main surface 20a. Specifically, the glass substrates 20 of samples 1 to 9 were sandblasted with alumina abrasive grains having grain sizes of #3000, #4000, #6000, and #8000 under conditions of air pressure of 0.2 to 0.4 MPa and a processing time of approximately 3 to 6 minutes, thereby forming an uneven shape consisting of minute irregularities on one of the main surfaces 20a.

[0079] The glass substrates 20 of the samples 10 to 13 serving as examples were subjected to wet blasting to form an uneven shape on one of the main surfaces 20a. Specifically, the glass substrates 20 of samples 10 to 13 were subjected to wet blasting treatment using alumina abrasive grains with a grain size of #8000 under conditions of an air pressure of 0.2 MPa and a nozzle scanning speed of 0.5 to 10 mm / s, thereby forming an uneven shape consisting of minute irregularities on one of the main surfaces 20a.

[0080] For the wet blasting treatment, the glass substrate 20 of each of Samples 10 to 13 was placed in an approximately vertical position, and 3 wt % abrasive grains made of alumina with a grain size of #8000, water, and a dispersant were uniformly stirred to prepare a slurry.The prepared slurry was sprayed from a round nozzle using air with a processing pressure of 0.2 MPa, and wet blasting was performed by scanning the round nozzle over the entire one main surface 20a of each glass substrate 20 while moving it at a speed of 0.5 to 10 mm / s. The reason why each glass substrate 20 is arranged in a substantially vertical position is to prevent the slurry sprayed onto the entire main surface 20a from remaining locally.

[0081] The glass substrate 20 of the sample 14 serving as a comparative example is not subjected to any treatment on one of the main surfaces 20a, that is, the glass substrate 20 of the sample 14 is untreated.

[0082] For the glass substrate 20 of Sample 15, which is a comparative example, a liquid containing an SiO2 component was sprayed onto one of the principal surfaces 20a, and the applied liquid containing an SiO2 component was dried to form an SiO2 coating film on the principal surface 20a. In other words, the glass substrate 20 of Sample 15 was coated with an SiO2 coating.

[0083] The glass substrates 20 of Samples 16 to 18, which are comparative examples, were prepared by immersing each glass substrate 20 in a hydrofluoric acid solution (25°C) adjusted to a concentration of 5 wt % for a predetermined time (Sample 16: approximately 17 minutes, Sample 17: approximately 33 minutes, Sample 18: 50 minutes). In other words, the glass substrates 20 of Samples 16 to 18 were subjected to hydrofluoric acid etching.

[0084] [Surface roughness measurement] First, the surface roughness of the main surface 20a of the glass substrate 20 of each of Samples 1 to 18 was measured. The surface roughness measurements were performed on the sandblasted main surface 20a for samples 1 to 9, on the wet blasted main surface 20a for samples 10 to 13, on the SiO2 coated main surface 20a for sample 15, and on one of the main surfaces 20a for samples 14 and 16 to 18.

[0085] The measured surface roughness parameters were the arithmetic mean height Sa, the maximum valley depth Sv, the average length RSm of the roughness curve element, the maximum peak height Rp of the roughness curve element, and the maximum valley depth Rv of the roughness curve element, and the surface roughness measurements were carried out using a white light interference microscope manufactured by Zygo (product name: New View 7300).

[0086] The measurement conditions were as follows: a 50x objective lens, a 2x zoom lens, a measurement area of ​​74 x 55 μm, a camera pixel count of 640 x 480, and 10 integrations. In addition, when measuring the arithmetic mean height Sa, the maximum valley depth Sv, the average length RSm of the roughness curve elements, the maximum peak height Rp of the roughness curve elements, and the maximum valley depth Rv of the roughness curve elements, the cutoff value λc1 of the high-pass filter λc was set to 14 μm, and the cutoff value λs1 of the low-pass filter λs was set to 0.35 μm.

[0087] [Surface roughness measurement results] The results of the surface roughness measurements performed on Samples 1 to 18 will be described. Table 2 shows the measurement results.

[0088] [Table 2]

[0089] As shown in Table 2, the arithmetic mean height Sa of the minute irregularities was in the range of 1.4 to 10.0 nm for Samples 1 to 13, which are examples. In contrast, in the comparative samples 14 to 18, the arithmetic mean height Sa of the untreated sample 14 was small at 0.1 nm, the arithmetic mean height Sa of the SiO2-coated sample 15 was large at 50.1 nm, and the arithmetic mean height Sa of the hydrofluoric acid-etched samples 16 to 18 was small, falling within the range of 0.2 to 0.3 nm.

[0090] Furthermore, for the examples 1 to 13, the maximum valley depth Rv of the roughness curve element was a value within the range of 9.4 to 57.5 nm, and the maximum peak height Rp of the curve element was a value within the range of 5.6 to 34.2 nm, and the relationship Rv>Rp was true for all samples. In contrast, in Samples 14 to 18 which are comparative examples, for the untreated Sample 14, the maximum valley depth Rv of the roughness curve element is 0.4 nm, the maximum peak height Rp of the curve element is 0.4 nm, and they are in the relationship of Rv = Rp. For the Sample 15 coated with SiO2, the maximum valley depth Rv of the curve element is 141.9 nm, the maximum peak height Rp of the curve element is 185.4 nm, and they are in the relationship of Rv < Rp. For Samples 16 to 18 subjected to hydrofluoric acid etching, the maximum valley depth Rv of the curve element is a value within the range of 0.8 to 1.0 nm, the maximum peak height Rp of the curve element is a value within the range of 0.8 to 0.9, and Rv and Rp are of comparable values.

[0091] In addition, the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa in the microasperities is a value within the range of 8.0 to 39.0 for Samples 1 to 13 which are examples, and Sv / Sa shows a value of 6 or more. In particular, for Samples 1 to 9 subjected to sandblasting treatment, the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa in the microasperities shows a value of 15 or more. In contrast, in Samples 14 to 18 which are comparative examples, the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa of the untreated Sample 14 was 12.6. Also, the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa of the Sample 15 coated with SiO2 was 5.5, and the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa of Samples 16 to 18 subjected to hydrofluoric acid etching was a value within the range of 5.6 to 5.8 nm, which was small.

[0092] Furthermore, the ratio Rv / RSm of the maximum valley depth Rv of the roughness curve element to the average length RSm of the roughness curve element was a value within the range of 0.0040 to 0.0229 for Samples 1 to 13 which are examples. In contrast, in comparative samples 14 to 18, the ratio Rv / RSm of the maximum valley depth Rv of the roughness curve elements to the average length RSm of the roughness curve elements of untreated sample 14 was a small 0.0004. The ratio Rv / RSm of the maximum valley depth Rv of the roughness curve elements to the average length RSm of the roughness curve elements of sample 15, which was coated with SiO2, was 0.0172. Furthermore, the ratio Rv / RSm of the maximum valley depth Rv of the roughness curve elements to the average length RSm of the roughness curve elements of samples 16 to 18, which were etched with hydrofluoric acid, was also small at 0.0005.

[0093] [Writing comfort rating] The writing feel when inputting characters, figures, etc. onto the glass substrate 20 with the input pen 50 was evaluated by a sensory test. The evaluation method involved using a Wacom refill (product name: elastomer refill (ACK-20004), pen tip diameter: 1.4 mm) attached to the housing of a Mitsubishi Pencil ballpoint pen (product name: JETSTREAM) as the input pen 50, and writing the character "a" on the glass substrate 20. When the pen tip was intuitively felt to be smooth and the writing feel was very good, a rating of ◎ was given; when the feeling was good, a rating of ○ was given; and when the feeling was felt to be poor due to non-slipness or the like, a rating of × was given.

[0094] [Writing comfort evaluation results] As shown in Table 2, for the examples, Samples 1 to 13, the elastomer pen tip felt smooth to operate, and the writing comfort rating was ⊚. On the other hand, for the comparative examples, untreated Sample 14, SiO2-coated Sample 15, and hydrofluoric acid-etched Samples 16 to 18, the elastomer pen tip felt hard to slide, and the writing comfort rating was x.

[0095] [Overall evaluation of each sample] From the above results, as shown in Table 2, it was found that for samples 1 to 13, which are examples, the appropriate micro-convex and concave shape formed on the main surface 20a with which the pen tip 51 of the input pen 50 comes into contact prevents the pen tip 51 from sliding on the main surface 20a of the glass substrate 20, and by combining this with a moderate reduction in the frictional force between the pen tip 51 and the main surface 20a, a good writing feel was obtained.

[0096] On the other hand, in the case of the untreated sample 14 as a comparative example, the main surface 20a that comes into contact with the input pen 50 has small irregularities, and the elastomer pen tip 51 is very difficult to slide, resulting in a poor writing feel. In addition, in the comparative example, Sample 15 with SiO2 coating, and Samples 16 to 18 with hydrofluoric acid etching, the pen tip 51 was too difficult to slide and caused sticking, resulting in a poor writing feel. [Explanation of symbols]

[0097] 10 Input Devices 20 Glass substrate (cover member for input device) 20a Main surface 30 Display elements (display devices) 40 Digitizer circuit (detection circuit) 50 Input Pen 51 Pen tip (friction element) Rp Maximum peak height of roughness curve element Rv: Maximum valley depth of roughness curve element RSm: average length of roughness curve element Sa arithmetic mean height Sv Maximum valley depth λc high-pass filter λc1 High-pass filter cutoff value λs low-pass filter λs1 Low-pass filter cutoff value

Claims

1. A cover member for an input device that is arranged on the front side of a display device in an input device, At least one main surface of the input device cover member has an uneven shape, A cover member for an input device, wherein a maximum valley depth Rv of the roughness curve elements on the main surface having the uneven shape is greater than a maximum peak height Rp of the roughness curve elements.

2. 2. The cover member for an input device according to claim 1, wherein the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa on the main surface having the irregular shape is 6 or more.

3. 2. The cover member for an input device according to claim 1, wherein the ratio Sv / Sa of the maximum valley depth Sv to the arithmetic mean height Sa on the main surface having the irregular shape is 15 or more.

4. 4. The cover member for an input device according to claim 1, wherein Rv / RSm, which is the ratio of the maximum valley depth Rv of the roughness curve element to the average length RSm of the roughness curve element on the main surface having the uneven shape, is 0.001 or more and 0.1 or less.

5. 5. The cover member for an input device according to claim 1, wherein an arithmetic mean height Sa of the main surface having the irregular shape is 1 nm or more and 50 nm or less.

6. 6. An input device comprising: the cover member for an input device according to claim 1; a display device; and a detection circuit for detecting pen input.

7. 7. The input device according to claim 6, further comprising an input pen that performs a pen input to the input device by moving while in contact with a main surface of the input device cover member.

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