Touch panel and display device

#The present invention relates to a touch panel that detects a position of a pointing object, and a display device including the touch panel.

#In recent years, display devices including a touch panel have been used. A touch panel is a device that detects a position touched with a pointing object such as a finger. Touch panels have been attracting attention as a means of an excellent user interface (UI). Various types of touch panels, such as a resistive film method and an electrostatic capacitive method, are made into products.

#As one touch panel of an electrostatic capacitive method, there is a touch panel of a projected electrostatic capacitive touch panel (see, for example, Japanese Patent Application Laid-Open No. 2012-103761). According to the projected electrostatic capacitive method, even when the front surface side of a sensor embedded in a touch panel is covered with a protection plate such as a glass plate having a thickness of approximately several millimeters, touch can be detected. This method allows disposition of the protection plate on the front surface, and thus has advantages in having excellent robustness, capability of detection of touch with gloves, and a long life owing to absence of movable parts, for example. For example, according to the technology of WO 2000/044018, a key matrix made of an array of a plurality of driving/receiving electrode pairs is provided. An electric field between electrodes varies depending on an object, such as a finger, that touches a substrate. Variation of coupling electrostatic capacitance (mutual electrode electrostatic capacitance) caused due to the variation of an electric field is detected as an electric charge amount.

#FIG. 1 is a partial cross-sectional diagram schematically illustrating a configuration of a display device according to a first embodiment.

#FIG. 2 is an exploded perspective view schematically illustrating a configuration of the display device according to the first embodiment.

#FIG. 3 is a plan view schematically illustrating a configuration of a touch panel according to the first embodiment.

#FIG. 1 is a partial cross-sectional diagram schematically illustrating a configuration of a display device 101 in which a touch panel 1 is provided on a display surface side according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view schematically illustrating a layer configuration on a front surface of the display device 101 of FIG. 1. FIG. 3 is a plan view schematically illustrating a configuration of the touch panel 1 of FIG. 1. Note that, in FIG. 2, illustration of members such as a position detection layer LD is simplified.

#FIG. 4 and FIG. 5 are diagrams illustrating configurations of FIG. 1 and FIG. 3 in more detail. Specifically, in FIG. 4 and FIG. 5, a reference electrode 41R and a detection electrode 41S, which are included in the concept of a second electrode 41 of FIG. 1 and FIG. 3, are illustrated. In the first embodiment, the second electrode 41 and the reference electrode 41R, or the second electrode 41 and the detection electrode 41S are not distinguished in description, unless otherwise specifically noted.

#The display device 101 of FIG. 1 (FIG. 4) includes a touch panel 1, a liquid crystal panel (display panel) 2, and a backlight unit 60. Note that illustration of the backlight unit 60 is simplified. Further, illustration of a metal-frame case that covers the liquid crystal panel 2 and the backlight unit 60 is omitted in FIG. 1 (FIG. 4).