COVER GLASS FOR PEN INPUT DEVICE AND METHOD FOR MANUFACTURING SAME
A cover glass for a pen input device has a haze value of less than 1%, and a Martens hardness within a range from 2000 N/mm 2 to 4000 N/mm 2 . When a moving member receiving a load of 150 gf (1.47 N) is moved in one direction, at 10 mm/sec, at room temperature, on the surface of the cover glass, a coefficient of kinetic friction μ k of a kinetic frictional force F k (N) exerted by the cover glass surface within a region where an approximately linear relationship is established between the kinetic frictional force F k (N) and the time is 0.14˜0.50, and a standard deviation σ (N) of the kinetic frictional force F k (N) is no more than 0.03. The moving member is a pen that includes a pen tip made of polyacetal resin with a Rockwell hardness of M90 and having a radius of curvature of 700 μm.
1 . A cover glass for a pen input device, the cover glass comprising a glass member having
a haze value of less than 1%; and
a Martens hardness within a range from 2000 N/mm 2 to 4000 N/mm 2 ;
wherein when a moving member receiving a load of 150 gf (1.47 N) is moved in one direction, at a velocity of 10 mm/sec, at room temperature, on a surface of the cover glass, a coefficient of kinetic friction μ k of a kinetic frictional force F k (N) between the moving member and the surface of the cover glass within a region where a relationship between the kinetic frictional force F k (N) and time is approximated by a straight line is greater than or equal to 0.14 and less than or equal to 0.50, and a standard deviation σ (N) of the kinetic frictional force F k (N) is less than or equal to 0.03; and
wherein the moving member is a pen that includes a pen tip made of polyacetal resin having a Rockwell hardness of M90, and the pen tip has a radius of curvature of 700 μm.
2 . The cover glass according to claim 1 , wherein
the surface of the cover glass includes a plurality of regions; and
the coefficients of kinetic friction μ k and the standard deviations σ (N) of the kinetic frictional force F k (N) exerted by the plurality of regions differ from one another
3 . A cover glass for a pen input device, the cover glass comprising a glass member having
a haze value of less than 1%; and
a Martens hardness within a range from 2000 N/mm 2 to 4000 N/mm 2 ;
wherein when a moving member is moved in one direction on a surface of the cover glass, assuming F k (N) represents a kinetic frictional force between the moving member and the surface of the cover glass, σ (N) represents a standard deviation of the kinetic frictional force F k (N), and Y represents σ/F k , Y is less than or equal to 0.05.
4 . The cover glass according to claim 3 , wherein
the surface of the cover glass includes a plurality of regions; and
the coefficients of kinetic friction μ k and the standard deviations σ (N) of the kinetic frictional force F k (N) exerted by the plurality of regions differ from one another.
5 . The cover glass according to claim 3 , wherein the Martens hardness of the cover glass is within a range from 2000 N/mm 2 to 3500 N/mm 2 .
6 . The cover glass according to claim 3 , wherein
the moving member is a synthetic leather; and
when the moving member receiving a load of 50 gf (0.49 N) is moved in one direction, at a velocity of 1 mm/sec, at room temperature, on the surface of the cover glass, a coefficient of kinetic friction μ k within a region where a relationship between the kinetic frictional force F k (N) and time is approximated by a straight line is greater than or equal to 0.9.
7 . The cover glass according to claim 3 , wherein the surface of the cover glass has
a surface roughness Ra (arithmetic average roughness) within a range from 0.2 nm to 20 nm; and
a surface roughness Rz (maximum height roughness) within a range from 3.5 nm to 200 nm.
8 . The cover glass according to claim 3 , wherein an anti-fingerprint material is coated on the surface of the cover glass.
9 . The cover glass according to claim 8 , wherein the anti-fingerprint material is coated on at least a portion of the surface of the cover glass.
10 . The cover glass according to claim 3 , wherein a glass composition of the cover glass includes:
SiO 2 at 61-77 mol %;
Al 2 O 3 at 1-18 mol %;
Na 2 O at 8-18 mol %;
K 2 O at 0-6 mol %;
MgO at 0-15 mol %;
B 2 O 3 at 0-8 mol %;
CaO at 0-9 mol %;
SrO at 0-1 mol %;
BaO at 0-1 mol %; and
ZrO 2 at 0-4 mol %.
11 . The cover glass according to claim 3 , wherein a chemical strengthening process is performed on the cover glass.
12 . The cover glass according to claim 3 , wherein a contact angle of the surface of the cover glass with respect to a water droplet is greater than or equal to 100 degrees.
13 . A cover glass for an input device used by a user to input information, the cover glass comprising a glass member having
a haze value of less than 1%; and
a Martens hardness within a range from 2000 N/mm 2 to 4000 N/mm 2 ;
wherein when a synthetic leather receiving a load of 50 gf (0.49 N) is moved in one direction, at a velocity of 1 mm/sec, at room temperature, on a surface of the cover glass, assuming F k (N) represents a kinetic frictional force between the synthetic leather and the surface of the cover glass, σ (N) represents a standard deviation of the kinetic frictional force F k (N), and Y represents σ/F k , a coefficient of kinetic friction μ k within a region where a relationship between the kinetic frictional force F k (N) and time is approximated by a straight line is greater than or equal to 0.9, and Y is less than or equal to 0.05.
14 . The cover glass according to claim 13 , wherein an input operation on the input device is performed by the user touching the cover glass with a finger.
15 . The cover glass according to claim 13 , wherein an input operation on the input device is performed by placing a pen in contact with the cover glass.