CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY

This application claims priority to Korean Patent Applications No. 10-2020-0008795 filed on Jan. 22, 2020 in the Korean Intellectual Property Office (KIPO), the entire disclosure of which is incorporated by reference herein.

BACKGROUND

1. Field

The present invention relates to a touch sensor and an image display device including the same. More particularly, the present invention relates to a touch sensor including patterned sensing electrodes and an image display device including the same.

2. Description of the Related Art

As information technologies are being developed, various demands in display devices having thinner dimension, light-weight, high efficiency in power consumption, etc., are increasing. The display device may include a flat panel display device such as a liquid crystal display (LCD) device, a plasma display panel (PDP) device, an electro-luminescent display device, an organic light emitting diode (OLED) display device, etc.

A touch panel or a touch sensor capable of inputting a user's direction by selecting an instruction displayed on a screen with a finger or an inputting tool is also developed. The touch panel or the touch sensor may be combined with the display device so that display and information input functions may be implemented in one electronic device.

In the touch sensor, sensing electrodes formed of a conductive material such as a metal for a touch sensing may be arranged on a substrate. However, when the touch sensor is inserted in the display device, an image quality implemented from the image display device may be degraded by the sensing electrodes. For example, the sensing electrodes may be visually recognized by the user to disturb the image.

Thus, construction of the sensing electrodes having improved optical and visual properties while maintaining desired electrical properties of the touch sensing is required.

For example, as disclosed in Korean Patent Application Publication No. 2014-0092366, various image display devices combined with a touch screen panel including a touch sensor has been developed recently. However, the touch sensor or the touch panel having improved optical and visual properties is continuously demanded.

SUMMARY

According to an aspect of the present invention, there is provided a touch sensor having improved optical and electrical properties.

According to an aspect of the present invention, there is provided an image display device including the touch sensor.

The above aspects of the present inventive concepts will be achieved by the following features or constructions:

(1) A touch sensor, including: a substrate layer; sensing electrodes arranged on a top surface of the substrate layer, the sensing electrodes having boundaries in which a plurality of convex portions are connected; and a dummy electrode disposed between the sensing electrodes, the dummy electrode having a boundary in which a plurality of convex portions are connected, wherein the sensing electrodes include a first sensing electrode arranged in a column direction and a second sensing electrode arranged in a row direction, and a convex portion in a region where the first sensing electrode, the second sensing electrode and the dummy electrode are adjacent to each other has a radius of curvature less than that of a convex portion in a region where only two of the first sensing electrode, the second sensing electrode and the dummy electrode are adjacent to each other.

(2) The touch sensor according to the above (1), further including a first separation region spacing the first sensing electrode and the second sensing electrode from each other, a second separation region spacing the first sensing electrode and the dummy electrode from each other, and a third separation region spacing the second sensing electrode and the dummy electrode from each other.

(3) The touch sensor according to the above (2), wherein the convex portions include: a first convex portion formed in an intersection area of the first separation region, the second separation region and the third separation region; and a second convex portion defined solely by the first separation region, the second separation region or the third separation region.

(4) The touch sensor according to the above (3), wherein the first convex portion has a radius of curvature less than that of the second convex portion.

(5) The touch sensor according to the above (4), wherein the radius of curvature of the first convex portion is less than 0.05.

(6) The touch sensor according to the above (1), wherein the dummy electrode includes: a first dummy electrode disposed between the first sensing electrode and the second sensing electrode neighboring each other; and a second dummy electrode surrounded by four sensing electrodes of the sensing electrodes.

(7) The touch sensor according to the above (6), wherein the second dummy electrode has an X-shape.

(8) The touch sensor according to the above (1), wherein the boundaries of the sensing electrodes and the dummy electrode have an amorphous wavy shape.

(9) The touch sensor according to the above (1), further including a floating electrode formed at an inside of each of the sensing electrodes.

(10) The touch sensor according to the above (9), wherein a boundary of the floating electrode has an amorphous wavy shape.

(11) The touch sensor according to the above (1), wherein the boundaries of the sensing electrodes are defined by setting an assembly of imaginary square unit cells that have sides deformed into a wavy shape, and then round-treating regions at which vertices the unit cells are located in a boundary of the assembly.

(12) The touch sensor according to the above (1), wherein the first sensing electrode comprises a plurality of first sensing electrodes and the second sensing electrode comprises a plurality of second sensing electrodes, wherein the touch sensor further includes a bridge electrode electrically connecting first sensing electrodes neighboring in the column direction of the plurality of first sensing electrodes; and a connecting portion integrally connecting second sensing electrodes neighboring in the row direction of the plurality of second sensing electrodes.

(13) A window stack structure, including: a window substrate; and the touch sensor according to embodiments as described above stacked on the window substrate.

(14) An image display device, including: a display panel; and the touch sensor according to embodiments as described above stacked on the display panel.

In a touch sensor according to embodiments of the present invention, a periphery of a sensing electrode may be formed so that a plurality of convex portions may be connected, and the periphery may include convex portions having different radii of curvature. A dummy electrode having a periphery of a random wavy shape may be included between neighboring sensing electrodes.

The periphery of the sensing electrode may be formed in a substantially random shape, so that electrode visibility and moiré phenomena caused by a regular repetition of an electrode pattern may be prevented

In exemplary embodiments, the convex portion of the sensing electrode adjacent to an end portion of the dummy electrode may have a relatively small radius of curvature. Accordingly, an electrode visual recognition occurring at an intersection between the sensing electrodes and the dummy electrode may be further reduced.

