BACKGROUND

1. Technical Field

The present invention relates to an electrowetting device.

2. Description of the Related Art

In recent years, electrowetting devices (also referred to as microfluidic devices or droplet devices) have been under development. Electrowetting is a phenomenon where a droplet that is placed on a hydrophobic dielectric layer, which is provided above an electrode, changes its angle of contact with respect to the dielectric layer in response to an electric field being applied thereto. By way of electrowetting, minute droplets, e.g., those in sub-microliter amounts, can be manipulated. Since electrowetting devices are often referred to as EWODs (Electrowetting on Dielectric Devices) in English, they may hereinafter be designated as EWODs for conciseness.

Japanese Laid-Open Patent Publication No. 2013-78758 discloses an active matrix type EWOD (also referred to as an “AM-EWOD”) in which an EWOD is driven by a thin-film electronic circuit (hereinafter also referred to as a “TFT circuit”) that includes thin film transistors (TFT).

SUMMARY

In an active matrix type EWOD, when any of a plurality of wiring lines for supplying control signals to the TFTs happens to break, voltage application to the electrode cannot occur from any TFT that is connected to the broken wiring line (which will hereinafter be referred to as a “defective line”). As a result, the region associated with that electrode cannot be changed from being hydrophobic to being hydrophilic. This hinders movements of the droplet because the droplet cannot move astride the defective line.

The present invention has been made in view of the above problem, and an objective thereof is to provide an electrowetting device in which a droplet can be moved astride a defective line.

The present specification discloses electrowetting devices as recited in the following Items.

[Item 1]

An electrowetting device comprising:

an active matrix substrate; and

a counter substrate opposed to the active matrix substrate via a predetermined gap,

the active matrix substrate including:

a first substrate;

a plurality of first electrodes disposed on the first substrate, the plurality of first electrodes being arranged in a matrix shape including a plurality of rows and a plurality of columns;

a plurality of TFTs respectively connected to the plurality of first electrodes; and

a first hydrophobic layer disposed on the plurality of first electrodes,

the counter substrate including:

a second substrate;

a second electrode disposed on the second substrate; and

a second hydrophobic layer disposed on the second electrode,

the active matrix substrate further including:

a plurality of first wiring lines extending along a row direction, the plurality of first wiring lines being connected to the plurality of TFTs; and

a plurality of second wiring lines extending along a column direction, the plurality of second wiring lines being connected to the plurality of TFTs, wherein,

the plurality of TFTs are disposed so as to have at least one of a first relative arrangement and a second relative arrangement,

the first relative arrangement being defined as a relative arrangement where two or more TFTs that are connected to any one of the plurality of first wiring lines alternately include, along the row direction: TFTs that are connected to the first electrodes belonging to one of a pair of rows adjoining the one first wiring line; and TFTs that are connected to the first electrodes belonging to the other row;

the second relative arrangement being defined as a relative arrangement where two or more TFTs that are connected to any one of the plurality of second wiring lines alternately include, along the column direction: TFTs that are connected to the first electrodes belonging to one of a pair of columns adjoining the one second wiring line; and TFTs that are connected to the first electrodes belonging to the other column.

[Item 2]

The electrowetting device of Item 1, wherein,

each of the plurality of TFTs includes a gate electrode, a source electrode, and a drain electrode; and

the plurality of first wiring lines are a plurality of row selection lines that are connected to the gate electrodes of the plurality of TFTs, and the plurality of second wiring lines are a plurality of column write lines that are connected to the source electrodes of the plurality of TFTs.

[Item 3]

The electrowetting device of Item 1 or 2, wherein the plurality of TFTs are disposed so as to have only one of the first relative arrangement and the second relative arrangement.

[Item 4]

The electrowetting device of Item 1 or 2, wherein the plurality of TFTs are disposed so as to have both of the first relative arrangement and the second relative arrangement.

[Item 5]

The electrowetting device of any of Items 1 to 4, wherein,

the plurality of first electrodes are disposed in each row with a predetermined first pitch P1, and disposed in each column with a predetermined second pitch P2; and

the plurality of first electrodes are disposed in such a manner that the first electrodes belonging to any odd-numbered row and the first electrodes belonging to any even-numbered row are mutually shifted along the row direction by a distance which is shorter than the first pitch P1, or that the first electrodes belonging to any odd-numbered column and the first electrodes belonging to any even-numbered column are mutually shifted along the column direction by a distance which is shorter than the second pitch P2.

[Item 6]

An electrowetting device comprising:

an active matrix substrate; and

a counter substrate opposed to the active matrix substrate via a predetermined gap,

the active matrix substrate including:

a first substrate;

a plurality of first electrodes disposed on the first substrate;

a plurality of TFTs respectively connected to the plurality of first electrodes; and

a first hydrophobic layer disposed on the plurality of first electrodes,

the counter substrate including:

a second substrate;

a second electrode disposed on the second substrate; and

a second hydrophobic layer disposed on the second electrode,

the active matrix substrate further including:

a plurality of first wiring lines extending along a row direction, the plurality of first wiring lines being connected to the plurality of TFTs; and

a plurality of second wiring lines extending along a column direction, the plurality of second wiring lines being connected to the plurality of TFTs, wherein,

the plurality of first electrodes are disposed in such a manner that any two adjacent first electrodes neighboring along a row direction, a column direction, or an oblique direction that is inclined with respect to the row direction and the column direction partially overlap each other via an insulating layer.

[Item 7]

The electrowetting device of Item 6, wherein the plurality of first electrodes are disposed in such a manner that any two adjacent first electrodes neighboring along the row direction or the column direction partially overlap each other via the insulating layer.

[Item 8]

The electrowetting device of Item 6, wherein the plurality of first electrodes are disposed in such a manner that any two adjacent first electrodes neighboring along the oblique direction partially overlap each other via the insulating layer.

According to an embodiment of the present invention, an electrowetting device in which a droplet can be moved astride a defective line can be provided.

