Input device and display device with input device

1. An input device comprising:

a plurality of input-position detecting electrodes arranged at a first interval along a first direction of a display plane;

at least one driving electrode which is arranged so as to be opposed to the plurality of input-position detecting electrodes and forms an electrostatic capacitance with the plurality of input-position detecting electrodes; and

an intermediate member disposed between the plurality of input-position detecting electrodes and the at least one driving electrode,

wherein when an ideal value of a width of each of the plurality of input-position detecting electrodes in the first direction is defined as Wsmax [μm], the first interval which is a center-to-center distance of adjacent input-position detecting electrodes among the plurality of input-position detecting electrodes is defined as P [μm], and an effective inter-electrode distance represented by an inverse number of a value obtained by dividing a relative permittivity of the intermediate member by a thickness of the intermediate member is defined as D [μm], Wsmax is represented by a following formula:

Ws max=0.488 ×P -4.33 ×D -160, and

the width of each of the plurality of input-position detecting electrodes in the first direction falls within a range of not more than ±150 μm of a value of the Wsmax.

2. The input device according to claim 1 ,

wherein a plurality of the intermediate members each having different relative permittivities are provided between the plurality of input-position detecting electrodes and the at least one driving electrode, and

D [μm] which is the effective inter-electrode distance is represented as an inverse number of a sum of values obtained by dividing relative permittivities of the plurality of intermediate members each having different relative permittivities by thicknesses thereof.

3. A display device with an input device comprising:

a display device which includes: a first substrate having a first surface; a second substrate which has a second surface opposed to the first substrate and is disposed on an opposite side to the first surface of the first substrate so as to be separated from the first substrate; a plurality of pixel electrodes arranged between the first substrate and the second substrate; at least one common electrode arranged between the first substrate and the second substrate; and a display function layer which is disposed between the first substrate and the second substrate and on which a display image is formed by applying a display voltage between the plurality of pixel electrodes and the at least one common electrode; and

an input device which is fixed to a first surface side of the first substrate,

wherein the input device includes a third substrate having a third surface and a fourth substrate which is opposed to the third substrate and disposed on a display device side compared with the third substrate,

the input device further includes:

a plurality of input-position detecting electrodes arranged at a first interval along a first direction of the third surface;

at least one driving electrode which is arranged so as to be opposed to the plurality of input-position detecting electrodes with interposing the third substrate therebetween and forms an electrostatic capacitance with the plurality of input-position detecting electrodes; and

an intermediate member disposed between the plurality of input-position detecting electrodes and the at least one driving electrode,

when an ideal value of a width of each of the plurality of input-position detecting electrodes in the first direction is defined as Wsmax [μm], the first interval which is a center-to-center distance of adjacent input-position detecting electrodes among the plurality of input-position detecting electrodes is defined as P [μm], and an effective inter-electrode distance represented by an inverse number of a value obtained by dividing a relative permittivity of the intermediate member by a thickness of the intermediate member is defined as D [μm], Wsmax is represented by a following formula:

Ws max=0.488 ×P -4.33 ×D -160, and

the width of each of the plurality of input-position detecting electrodes in the first direction falls within a range of not more than ±150 μm of a value of the Wsmax.

4. A display device with an input device comprising:

a display device which includes: a first substrate having a first surface; a second substrate which has a second surface opposed to the first substrate and is disposed on an opposite side to the first surface of the first substrate so as to be separated from the first substrate; a plurality of pixel electrodes arranged between the first substrate and the second substrate; at least one common electrode arranged between the first substrate and the second substrate; and a display function layer which is disposed between the first substrate and the second substrate and on which a display image is formed by applying a display voltage between the plurality of pixel electrodes and the at least one common electrode; and

a plurality of input-position detecting electrodes which are formed on an opposite side of the second substrate with interposing the first substrate therebetween and form an electrostatic capacitance with the at least one common electrode of the display device, thereby detecting an input position,

wherein the plurality of input-position detecting electrodes are arranged at a first interval along a first direction of the first surface,

when an ideal value of a width of each of the plurality of input-position detecting electrodes in the first direction is defined as Wsmax [μm], the first interval which is a center-to-center distance of adjacent input-position detecting electrodes among the plurality of input-position detecting electrodes is defined as P [μm], and an effective inter-electrode distance represented by an inverse number of a value obtained by dividing a relative permittivity of an intermediate member disposed between the plurality of input-position detecting electrodes and the at least one common electrode by a thickness of the intermediate member is defined as D [μm], Wsmax is represented by a following formula:

Ws max=0.488 ×P -4.33 ×D -160, and

the width of each of the plurality of input-position detecting electrodes in the first direction falls within a range of not more than ±150 μm of a value of the Wsmax.

5. A display device with an input device comprising:

a display device which includes: a first substrate having a first surface; a second substrate which has a second surface opposed to the first substrate and is disposed on an opposite side to the first surface of the first substrate so as to be separated from the first substrate; a plurality of pixel electrodes arranged between the first substrate and the second substrate; at least one common electrode arranged between the first substrate and the second substrate; and a display function layer which is disposed between the first substrate and the second substrate and on which a display image is formed by applying a display voltage between the plurality of pixel electrodes and the at least one common electrode;

a plurality of input-position detecting electrodes which are formed on an opposite side of the second substrate with interposing the first substrate therebetween and form an electrostatic capacitance with the at least one common electrode of the display device, thereby detecting an input position; and

a third substrate disposed so as to be opposed to the first surface,

wherein the plurality of input-position detecting electrodes are arranged on at least one surface of the third substrate at a first interval along a first direction,

when an ideal value of a width of each of the plurality of input-position detecting electrodes in the first direction is defined as Wsmax [μm], the first interval which is a center-to-center distance of adjacent input-position detecting electrodes among the plurality of input-position detecting electrodes is defined as P [μm], and an effective inter-electrode distance represented by an inverse number of a value obtained by dividing a relative permittivity of an intermediate member disposed between the plurality of input-position detecting electrodes and the at least one common electrode by a thickness of the intermediate member is defined as D [μm], Wsmax is represented by a following formula:

Ws max=0.488 ×P -4.33 ×D -160, and

the width of each of the plurality of input-position detecting electrodes in the first direction falls within a range of not more than ±150 μm of a value of the Wsmax.