Cover member for input device, and input device

Abstract

To provide an input device cover member and an input device capable of realizing excellent writing comfort in an input operation to the input device.SOLUTION: A glass substrate 20 as an input device cover member arranged on a front face of a display element 30 in an input device 10 has an uneven shape on at least one main surface 20a of the glass substrate 20. A maximum valley depth Rv of a roughness curve element on the main surface 20a having the uneven shape is larger than a maximum peak height Rp of the roughness curve element.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 Art

[0002] Conventionally, a pen input device has been known in which a user can perform input operations such as writing characters and figures on a screen by hand using an input pen.

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

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

[0005] Therefore, in order to prevent the input pen from slipping easily, using a pen tip made of an elastomer material having a high coefficient of friction is disclosed in Patent Document 1. In addition, Patent Document 2 discloses a cover glass (cover member) in which minute irregularities are formed on the glass surface by an etching process to increase the frictional force and improve the writing feel.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] However, when using a pen tip made of elastomer material as described in Patent Document 1, the flexibility of the pen tip improves the writing feel, but because the elastomer material has a strong adhesive force to the cover member, the pen tip becomes too slippery, and when the input pen is brought into contact with the surface of the cover member and moved, the writing feel can actually worsen. Furthermore, even when using a pen tip made of an elastomer material with high adhesion force to the cover glass described in Patent Document 2, the frictional force between the pen tip and the cover glass became too high when the input pen was repeatedly brought into contact with the surface of the cover glass and moved, resulting in an unsatisfactory writing experience.

[0008] This invention has been made in view of the problems of the current situation described above, and provides an input device cover member and an input device that can achieve excellent writing comfort when inputting to an input device, even when a material with a high coefficient of friction, such as an elastomer, is used for the pen tip. [Means for solving the problem]

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

[0010] In other words, the input device cover member according to the present invention is an input device cover member disposed on the front side of a display device in an input device, wherein at least one main surface of the input device cover member 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. With this configuration, the cover member for the 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, suppressing an excessive increase in frictional force between the main surface and the pen tip, and enabling a superior writing experience during input operations to 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, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa on the main surface having an uneven shape, is 6 or more. With this configuration, the cover member for the input device according to the present invention suppresses an excessive increase in frictional force between the main surface and the pen tip, thereby achieving a superior writing feel during input operations on the input device.

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

[0013] Furthermore, in the input device cover member according to the present invention, it is preferable that the ratio Rv / RSm, which is the ratio of the maximum valley depth Rv of the roughness curve elements to the average length RSm of the roughness curve elements on the main surface having the uneven shape, is 0.001 or more and 0.1 or less. With this configuration, the cover member for the input device according to the present invention allows the pen tip to slide appropriately against the main surface, thereby achieving an excellent writing feel during input operations on the input device.

[0014] Furthermore, in the cover member for the input device according to the present invention, it is preferable that the arithmetic mean height Sa of the main surface having the uneven shape is 1 nm or more and 50 nm or less. With this configuration, the cover member for the input device according to the present invention moderately suppresses the slippage of the pen tip on the main surface and moderately reduces the slipperiness of the pen tip on the main surface, thereby providing an excellent writing feel with the input pen during input operations to the input device.

[0015] The input device according to the present invention is characterized by including any one of the above-described cover members for the input device, a display device, and a detection circuit that detects pen input. The input device according to the present invention is characterized by including an input pen that performs a pen input to the input device by moving while contacting the main surface of the cover member for the input device. With such a configuration, according to the input device of the present invention, excellent writing feel can be realized in the input operation to the input device by the input pen.

Effect of the Invention

[0016] According to the present invention, excellent writing feel can be realized in the input operation to the input device.

Brief Description of the Drawings

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

[0021] The input device 10 is configured to allow pen input (input operation) of characters and figures by moving the input pen 50 while it is in contact with the 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 term "tablet device" broadly refers to a pen input display device equipped with 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 made of a transparent glass plate on which an uneven shape is formed on at least one main surface (in this embodiment, the main surface 20a). Furthermore, the glass substrate 20 is positioned such that the main surface 20a, which has an uneven surface, is the surface that the input pen 50 contacts.

[0024] Here, the glass substrate 20 can be, for example, a glass plate made of aluminosilicate glass or borosilicate glass. Furthermore, if 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 its surface. Further details about the glass substrate 20 will be described later.

[0025] The digitizer circuit 40 is equipped with a detection sensor that detects input operations performed by the input pen 50. Furthermore, the input pen 50 is an input device shaped like a writing instrument 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. 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 grip even fine irregular shapes. Therefore, when the pen tip 51 of the input pen 50 is brought into contact with the main surface 20a of the glass substrate 20, which has an uneven surface, and moved, a particularly excellent writing experience can be achieved.

[0027] In this embodiment, a glass substrate 20 is used as the cover member for the input device, but the invention is not limited to this. For example, a resin substrate made of synthetic resin, with an uneven surface 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 applying a blasting process such as wet blasting to the main surface of the resin substrate, or by applying an embossing process to the main surface of the resin substrate.

[0028] Furthermore, a resin layer with an uneven surface is laminated onto at least one main surface of a glass substrate, and this can also be used as a cover component for an input device. In this case, the cover member can be constructed by attaching a resin sheet with an uneven surface to the main surface of a glass substrate.

[0029] The uneven surface of the resin sheet can be formed, for example, by embossing the surface of the resin sheet or by forming a sheet of synthetic resin mixed with powder or granules. 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, etc., the hardness of the surface (especially the main surface that contacts 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, the ratio Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is preferably 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 elements in this application conform to JIS B0601 2013, while the arithmetic mean height Sa and maximum valley depth Sv conform to ISO 25178.

[0035] In the small irregularities of the main surface 20a, the arithmetic mean height Sa is the average of the absolute values ​​of the peak height Za and valley depth Zb 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 minute irregularities on a given surface.

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

[0037] The above-mentioned values ​​for 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 are values ​​obtained from the roughness curve obtained when the cutoff value λc1 of the high-pass filter λc for blocking 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 blocking 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 (refer to 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 respectively, it is possible to improve the writing feel of the input pen 50 while maintaining the visibility of the display element 30 (also refer to 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 sparkling 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 scratch resistance is high and it is difficult to get 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. Also, the contribution of the frictional force varies 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 modulus of elasticity, the flatter the main surface 20a of the glass substrate 20, the greater the frictional force due to adhesion, and the less likely the pen tip 51 is to slip against the main surface 20a of the glass substrate 20. In this case, by creating 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 against the main surface 20a of the glass substrate 20.

[0043] On the other hand, in the case of a 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 against the main surface 20a of the glass substrate 20. To address this, by creating minute irregularities on the main surface 20a of the glass substrate 20, the pen tip 51 of the input pen 50 can be made to grip the main surface 20a more easily. This increases the frictional force between the main surface 20a and the pen tip 51, making it moderately difficult for the pen tip 51 to slip against the main surface 20a of the glass substrate 20.

[0044] Furthermore, in the case of a pen tip 51 made of a felt-like material, it exhibits similar behavior to the POM pen tip 51 described above. By creating 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 moderately difficult for the pen tip 51 to slip against the main surface 20a of the glass substrate 20.

[0045] In this way, by creating minute irregularities on the main surface 20a of the glass substrate 20, it is possible to moderately suppress the slippage of the pen tip 51 of the input pen 50, which is made of various materials (elastomer, POM, and felt), on the main surface 20a, or moderately reduce the slipperiness of the pen tip 51 on the main surface 20a. This makes it possible to improve the writing feel of the input pen 50 when inputting to 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 is moderately suppressed, and the slipperiness of the pen tip 51 on the main surface 20a is moderately reduced, enabling the writing feel when inputting to the input device 10 with the input pen 50 to be excellent.

[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 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 frictional force can be suppressed. In particular, the pen tip 51 made of an elastomer with strong adhesion contributes to a reduction in 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, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is set to 6 or more. However, it is preferable that Sv / Sa be set to 8 or more, more preferably to 10 or more, even more preferably to 12 or more, and particularly preferably to 15 or more.

[0051] When the ratio Sv / Sa, which is the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, is 6 or greater, it indicates that the surface of the minute irregularities has deep valleys. Therefore, when the ratio Sv / Sa is 6 or greater, an excessive increase in frictional force between the main surface 20a and the pen tip 51 is suppressed, making it possible to achieve a superior writing feel when inputting to the input device 10. In particular, when the ratio Sv / Sa is 15 or greater, an excessive increase in frictional force between the main surface 20a and the pen tip 51 is suppressed even further, making it possible to achieve an even superior writing feel when inputting to the input device 10.

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

[0053] Specifically, a larger value of Rv / RSm, which is the ratio of the average length RSm of the roughness curve elements to the maximum valley depth Rv of the roughness curve elements, results in deeper valleys. When the valleys of the micro-irregularities become deeper, in the case of a pen tip 51 made of elastomer, a material with 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 decreases, and the pen tip 51 can slide appropriately against the main surface 20a. This makes it possible to achieve a superior writing feel when inputting to the input device 10.

[0054] Furthermore, when the valleys of the minute irregularities become deeper, in the case of a pen tip 51 made of a hard material such as POM, it is possible to suppress the increase in frictional force due to excessive catching of the pen tip 51 against the minute irregularities of the main surface 20a, and to make the pen tip 51 slide appropriately against the main surface 20a. This makes it possible to achieve a superior writing feel when inputting to the input device 10.

[0055] As described above, in this embodiment, the lower limit of Rv / RSm, which is the ratio of the average length RSm of the roughness curve elements to the maximum valley depth Rv of the roughness curve elements, is set to 0.001. However, it is preferable that this lower limit be set to 0.002, and even more preferable that it be set 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 elements to the maximum valley depth Rv of the roughness curve elements, is too large, the valley shape of the minute irregularities becomes locally too sharp, making it easier for the pen tip 51, which is a friction element, to bite into it. This generates excessive friction between the main surface 20a and the pen tip 51, resulting in a decrease in writing comfort. Therefore, in this embodiment, the upper limit 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. However, it is preferable that this upper limit be 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 is made of a material that allows for adjustment of frictional force against uneven surfaces, such as the aforementioned elastomer and POM synthetic resin materials, felt, and composite materials of felt and synthetic resin materials, resulting in a particularly superior writing feel for the pen tip 51.

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

[0059] Furthermore, an anti-reflective coating can be formed on the main surface 20a of the glass substrate 20 to reduce the reflectivity on the side that the input pen 50 contacts, or an anti-fouling coating can be formed to prevent fingerprint adhesion and provide water-repellent and oil-repellent properties.

[0060] When the glass substrate 20 is used as a cover member for the input device 10, the anti-reflective coating described above is formed on at least the main surface 20a on the front side (the side that the input pen 50 contacts) of the glass substrate 20. Furthermore, if there is a gap between the glass substrate 20 and the display element 30, it is preferable to also have an anti-reflective coating on the main surface 20b on the back side (the side facing the display element 30) of the glass substrate 20.

[0061] As an anti-reflective coating, for example, a low refractive index coating with a refractive index lower than that of the glass substrate 20, or a dielectric multilayer film in which a low refractive index coating with a relatively low refractive index and a high refractive index coating with a relatively high refractive index are alternately laminated can be used. The anti-reflective coating can be formed by sputtering or CVD.

[0062] When the main surface 20a of the glass substrate 20 has an anti-reflective coating, the uneven shape of the main surface 20a of the glass substrate 20 is formed such that the surface irregularities of the anti-reflective coating fall within the range of the above-mentioned surface roughness (values ​​of the arithmetic mean height Sa of 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). Furthermore, if the main surface 20a of the glass substrate 20 has an anti-reflective coating, the uneven shape of the main surface 20a of the glass substrate 20 is formed such that the haze of the glass substrate 20 having the anti-reflective coating falls within the range described above.

[0063] Furthermore, when measuring 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 after the anti-reflective coating has been formed, a 10 nm thick 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 antifouling film described above is formed on the main surface 20a of the front side (the side that the input pen 50 contacts) of the glass substrate 20. Furthermore, it is preferable that the antifouling film contains a fluorine-containing polymer that includes silicon in its main chain.

[0065] As fluorine-containing polymers, for example, polymers having -Si-O-Si- units in the main chain and water-repellent functional groups containing fluorine in the side chains can be used. Fluorine-containing polymers can be synthesized, for example, by dehydration condensation of silanol.

[0066] Furthermore, when forming an anti-reflective coating and an anti-fouling coating on the main surface 20a of the glass substrate 20, the anti-reflective coating is formed on the main surface 20a of the glass substrate 20, and the anti-fouling coating is formed on the anti-reflective coating.

[0067] 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 both an anti-reflective film and an antifouling film, the uneven shape of the main surface 20a of the glass substrate 20 is formed such that the surface irregularities of the antifouling film are within the range of the above-mentioned surface roughness (arithmetic mean height Sa of minute irregularities, 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, and maximum valley depth Rv of roughness curve elements). Furthermore, if the main surface 20a of the glass substrate 20 has an antifouling film, or if the main surface 20a of the glass substrate 20 has both an anti-reflective film and an antifouling film, the uneven shape of the main surface 20a of the glass substrate 20 is formed such that the haze of the glass substrate 20 after the formation of the antifouling film, or the haze of the glass substrate 20 after the formation of both the anti-reflective film and the antifouling film, falls within the range described above.

[0068] When forming a chemically strengthened layer 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 techniques that involve immersing a glass substrate in a molten salt containing alkali metals, thereby replacing the smaller alkali metal (ions) present on the outermost surface of the glass substrate 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 sizes than the original atoms before treatment are arranged. For example, if the glass substrate contains sodium (Na), this sodium is replaced with potassium (K) in the molten salt (e.g., nitrate) during the chemical strengthening process. This allows for the formation of a compressive stress layer on the surface of the glass substrate, thereby improving its strength.

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

[0070] [Method for manufacturing the glass substrate 20] Next, the manufacturing method for the glass substrate 20 will be explained using Figure 1. The irregularities formed on at least one main surface 20a of the glass substrate 20 are formed by combining at least one type of processing method, such as sandblasting and wet blasting, on the main surface 20a.

[0071] Sandblasting is a process that creates fine irregularities on a workpiece by using compressed air to spray solid particles such as alumina onto a glass workpiece at high speed from a nozzle. In contrast, wet blasting is a process that creates fine irregularities on a glass workpiece by uniformly mixing abrasive particles, which are composed of solid particles such as alumina, with a liquid such as water to form a slurry, and then using compressed air to spray this slurry onto a glass workpiece at high speed from a nozzle.

[0072] In both sandblasting and wet blasting processes, when abrasive particles are ejected at high speed and collide with the workpiece, the abrasive particles in the slurry scrape, strike, or rub the surface of the workpiece, thereby forming fine irregularities on the workpiece surface. 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, and #8000, it is possible to create minute irregularities.

[0073] The surface roughness of the minute irregularities formed on the main surface of a workpiece by sandblasting and wet blasting (arithmetic mean height Sa, 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) can be adjusted mainly by the particle size distribution of the abrasive particles sprayed and the spraying pressure when spraying the slurry onto the workpiece.

[0074] Sandblasting and wet blasting processes involve spraying abrasive particles onto the workpiece at high speed, causing the edges of the abrasive particles to penetrate the workpiece, resulting in the formation of deep grooves in the workpiece. [Examples]

[0075] Next, an example of a glass substrate 20 in which an uneven shape is formed on one of its main surfaces 20a by sandblasting or wet blasting will be described. The configuration of the glass substrate 20 is not limited to those shown below.

[0076] [Sample preparation] In this embodiment, as shown in Table 1, samples 1 to 13 were prepared as examples of the glass substrate 20, and samples 14 to 18 were prepared as comparative examples to these examples. For samples 1 to 18, alkali-containing aluminosilicate glass with a thickness of 0.55 mm was used as the glass substrate 20.

[0077] [Table 1]

[0078] For the glass substrates 20 of samples 1 to 9, which serve as examples, a sandblasting treatment was performed to create an uneven surface on one of the main surfaces 20a. Specifically, alumina abrasive grains with particle sizes #3000, #4000, #6000, and #8000 were sandblasted onto the glass substrates 20 of samples 1 to 9 under conditions of air pressure of 0.2 to 0.4 MPa and processing time of approximately 3 to 6 minutes, thereby forming a textured surface consisting of minute irregularities on one of the main surfaces 20a.

[0079] For the glass substrates 20 of the examples 10 to 13, a wet blasting treatment was performed to create an uneven surface on one of the main surfaces 20a. Specifically, the glass substrates 20 of samples 10 to 13 were subjected to wet blasting with alumina abrasive grains of #8000 under conditions of air pressure of 0.2 MPa and nozzle scanning speed of 0.5 to 10 mm / s, thereby forming a textured surface consisting of minute irregularities on one of the main surfaces 20a.

[0080] For the wet blasting treatment, each of the glass substrates 20 of samples 10 to 13 was placed in a nearly vertical position, and a slurry was prepared by uniformly stirring 3 wt% of abrasive particles made of alumina with a particle size of #8000, water, and a dispersant. The prepared slurry was then sprayed from a round nozzle using air at a processing pressure of 0.2 MPa, and wet blasting was performed by scanning the entire surface of one main surface 20a of each glass substrate 20 while moving the round nozzle at a speed of 0.5 to 10 mm / s. The reason each glass substrate 20 is positioned in a nearly vertical orientation is to prevent the slurry sprayed onto the entire main surface 20a from remaining in localized areas.

[0081] In the case of the comparative example sample 14, the glass substrate 20 was not treated on one of its main surfaces 20a. In other words, the glass substrate 20 of sample 14 was untreated.

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

[0083] For comparative examples, the glass substrates 20 of samples 16-18 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 16-18 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 samples 1 to 18 was measured. Surface roughness was measured on the main surface 20a that had been sandblasted for samples 1-9, on the main surface 20a that had been wet blasted for samples 10-13, on the main surface 20a that had been coated with SiO2 for sample 15, and on one of the main surfaces 20a for samples 14, 16-18.

[0085] The parameters for surface roughness measured were the arithmetic mean height Sa, maximum valley depth Sv, average length RSm of the roughness curve elements, maximum peak height Rp of the roughness curve elements, and maximum valley depth Rv of the roughness curve elements. Surface roughness was measured using a white light interference microscope. The white light interference microscope used was a Zygo New View 7300.

[0086] The measurement conditions were set to use a 50x objective lens and a 2x zoom lens, with a camera resolution of 640x480 pixels and 10 integrations for a measurement area of ​​74x55μm. Furthermore, when measuring the arithmetic mean height Sa, maximum valley depth Sv, 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, 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 surface roughness measurements performed on samples 1 to 18 are described below. Table 2 shows the measurement results.

[0088] [Table 2]

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

[0090] Furthermore, for the examples of samples 1 to 13, the maximum valley depth Rv of the roughness curve elements was within the range of 9.4 to 57.5 nm, and the maximum peak height Rp of the curve elements was within the range of 5.6 to 34.2 nm, with the relationship Rv > Rp being 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. Also, 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 nm, and Rv and Rp are of comparable values.

[0091] Moreover, 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 examples 14-18, the ratio Rv / RSm of the untreated sample 14, which is the ratio of the maximum valley depth Rv to the average length RSm of the roughness curve elements, was small at 0.0004. The ratio Rv / RSm of the SiO2-coated sample 15, which is the ratio of the maximum valley depth Rv to the average length RSm of the roughness curve elements, was 0.0172. Furthermore, the ratio Rv / RSm of the hydrofluoric acid-etched samples 16-18, which is the ratio of the maximum valley depth Rv to the average length RSm of the roughness curve elements, was small at 0.0005.

[0093] [Evaluation of writing comfort] The writing feel when inputting characters and shapes onto a glass substrate 20 using an input pen 50 was evaluated through a sensory test. The evaluation method involved using a Wacom replacement nib (product name: Elastomer nib (ACK-20004), pen tip diameter: 1.4mm) attached to the casing of a Mitsubishi Pencil ballpoint pen (product name: JETSTREAM) as the input pen 50. When writing the character "あ" on the glass substrate 20, a score of ◎ was given if the pen tip was intuitively smooth and the writing feel was excellent, a score of ○ if it felt good, and a score of × if it felt slippery or otherwise unpleasant.

[0094] [Evaluation results of writing comfort] As shown in Table 2, for samples 1 to 13, which are examples, the elastomer pen tip was perceived as being smooth to operate, resulting in a writing comfort rating of ◎. On the other hand, for the comparative examples, untreated sample 14, sample 15 with SiO2 coating, and samples 16 to 18 with hydrofluoric acid etching, the elastomer pen tip was perceived as not being slippery, resulting in a writing comfort rating of ×.

[0095] [Overall evaluation of each sample] From the results above, as shown in Table 2, for the examples of samples 1 to 13, the appropriate micro-irregular shape formed on the main surface 20a to which the pen tip 51 of the input pen 50 contacts suppresses the slippage of the pen tip 51 on the main surface 20a of the glass substrate 20, and the result is that a good writing feel is obtained by combining this with an appropriate reduction in the frictional force between the pen tip 51 and the main surface 20a.

[0096] On the other hand, in the case of the untreated sample 14, which was a comparative example, the surface irregularities of the main surface 20a that the input pen 50 contacts were small, and in the case of the elastomer pen tip 51, it became very difficult to slip, resulting in a poor writing experience. Furthermore, in the comparative examples, sample 15, which was coated with SiO2, and samples 16-18, which were etched with hydrofluoric acid, the pen tip 51 was too stiff, causing snagging and resulting in a poor writing experience. [Explanation of symbols]

[0097] 10 Input devices 20. Glass substrate (cover component for input device) 20a Main surface 30 Display elements (display devices) 40. Digitizer circuit (detection circuit) 50 Input Pen 50 51 Pen tip (friction element) Rp Roughness Curve Element Maximum Peak Height Rv Roughness Curve Element Maximum Valley Depth RSm Roughness Curve Average Length Sa arithmetic mean height Sv Maximum valley depth λc high-pass filter λc1 High-pass filter cutoff value λs low-pass filter λs1 is the cutoff value of the low-pass filter.

Claims

1. An input device cover member that is positioned on the front side of the display device in the input device, The main surface of at least one of the input device cover members has an uneven shape, In the main surface having the aforementioned uneven shape, the maximum valley depth Rv of the roughness curve element is greater than the maximum peak height Rp of the roughness curve element. In the main surface having the aforementioned uneven shape, the ratio of the maximum valley depth Sv to the arithmetic mean height Sa, Sv / Sa, is 6 or more. In the main surface having the aforementioned uneven shape, the average length RSm of the roughness curve elements is 2.1 μm or more, and the ratio Rv / RSm, which is the ratio of the maximum valley depth Rv of the roughness curve elements to the average length RSm of the roughness curve elements, is 0.001 or more and 0.1 or less. The values ​​of the maximum valley depth Rv, the maximum peak height Rp, and the average length RSm of the roughness curve element are: This value is obtained when the cutoff value of the high-pass filter λc is set to 14 μm and the cutoff value of the low-pass filter λs is set to 0.35 μm, in accordance with JIS B0601 2013. The values ​​of the maximum valley depth Sv and the arithmetic mean height Sa are, This value is obtained when the cutoff value of the high-pass filter λc is set to 14 μm and the cutoff value of the low-pass filter λs is set to 0.35 μm, in accordance with ISO 25178. A cover member for an input device characterized by the following features.

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

3. The arithmetic mean height Sa of the main surface having the aforementioned uneven shape is 1 nm or more and 50 nm or less. A cover member for an input device according to claim 1 or 2.

4. The maximum valley depth Rv of the roughness curve element in the main surface having the uneven shape is 57.5 nm or less. A cover member for an input device according to any one of claims 1 to 3, characterized by the features described herein.

5. The maximum peak height Rp of the roughness curve element on the main surface having the uneven shape is 34.2 nm or less. The cover member for an input device according to any one of claims 1 to 4.

6. The device comprises an input device cover member according to any one of claims 1 to 5, a display device, and a detection circuit for detecting pen input. An input device characterized by the following features.

7. The system includes an input pen that performs pen input to the input device by moving while in contact with the main surface of the cover member for the input device. The input device according to feature 6.

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