Method for selecting writing sheet for stylus, touchscreen system, writing sheet for stylus, touchscreen, and display device

A touch panel system comprising:

• a touch panel comprising a writing sheet for a touch panel pen on a surface;
• and a touch panel pen, wherein the touch panel system satisfies the following conditions 1-1 and 1-2:
• <Condition 1-1>
• a sound that arises when the touch panel pen is brought into contact with a surface of the writing sheet for a touch panel pen at an acute angle of 25 to 35 degrees and, while maintaining the angle, a vertical load of 45 to 55 gf is applied to the touch panel pen and the touch panel pen is reciprocatingly moved 45 to 55 mm in one-way length at a rate of 180 to 220 mm/sec is recorded;
• when recording, the sound is converted from an analog signal to a digital signal at a sampling frequency of 44.1 kHz and recorded;
• a soundless portion is added to before and after the sound converted into a digital signal so that an overall time period of the digital signal becomes 0.7 seconds;
• the digital signal to which the soundless portion has been added is subjected to fast Fourier transform in which a range of variables is 1 Hz to 22,000 Hz and the Hanning window is adopted as a window function, and a sound pressure (dB/Hz) is calculated for each 1 Hz;
• values of the dB/Hz at frequencies from 1 Hz to 20,000 Hz are normalized to have a maximum value of 100 and a minimum value of 0;
• the normalized values of dB/Hz are adopted as rated sound pressures P;
• the frequencies from 1 Hz to 20,000 Hz are divided into ten segments of 2,000 Hz each, and integrated values of the rated sound pressures P of each segment are calculated;
• when an integrated value of the rated sound pressures P for frequencies of 1 Hz or more to less than 2,000 Hz that is a first segment is represented by P1, and an integrated value of the rated sound pressures P for frequencies of 18,000 Hz or more to 20,000 Hz or less that is a tenth segment is represented by P10, P1/P10 exhibits a value of 1.25 or more;
• and
• <Condition 1-2>
• when a standard deviation σ of the integrated values of the rated sound pressures P of the ten segments is calculated, σ exhibits a value of 13,500 or less.

A writing sheet for a touch panel pen having a surface that satisfies the following conditions 1-1 and 1-2:

• <Condition 1-1>
• a sound that arises when a touch panel pen is brought into contact with a surface of a writing sheet for a touch panel pen at an acute angle of 25 to 35 degrees and, while maintaining the angle, a vertical load of 45 to 55 gf is applied to the touch panel pen and the touch panel pen is reciprocatingly moved 45 to 55 mm in one-way length at a rate of 180 to 220 mm/sec is recorded;
• when recording, the sound is converted from an analog signal to a digital signal at a sampling frequency of 44.1 kHz and recorded;
• a soundless portion is added to before and after the sound converted into a digital signal so that an overall time period of the digital signal becomes 0.7 seconds;
• the digital signal to which the soundless portion has been added is subjected to fast Fourier transform in which a range of variables is 1 Hz to 22,000 Hz and the Hanning window is adopted as a window function, and a sound pressure (dB/Hz) is calculated for each 1 Hz;
• values of the dB/Hz at frequencies from 1 Hz to 20,000 Hz are normalized to have a maximum value of 100 and a minimum value of 0;
• the normalized values of dB/Hz are adopted as rated sound pressures P;
• the frequencies from 1 Hz to 20,000 Hz are divided into ten segments of 2,000 Hz each, and integrated values of the rated sound pressures P of each segment are calculated;
• when an integrated value of the rated sound pressures P for frequencies of 1 Hz or more to less than 2,000 Hz that is a first segment is represented by P1, and an integrated value of the rated sound pressures P for frequencies of 18,000 Hz or more to 20,000 Hz or less that is a tenth segment is represented by P10, P1/P10 exhibits a value of 1.25 or more;
• and
• <Condition 1-2>
• when a standard deviation σ of the integrated values of the rated sound pressures P of the ten segments is calculated, σ exhibits a value of 13,500 or less.