1. Technical Field
The present invention relates to a display device, a method of driving a display device, and an electronic apparatus, and more particularly, to a display device, a method of driving a display device, and an electronic apparatus that have an idle period in which display is stopped between display operation periods.
2. Description of the Related Art
In recent years, attention has been paid to touch detection devices referred to as so-called touch panels capable of detecting external proximity objects which approach from the outside. The touch panels are mounted on or integrated with a display device such as a liquid crystal display device and are used for display devices with a touch detection function. The display devices with a touch detection function display various button images on the display device, thereby enabling input of information with the touch panel as a substitute for ordinary mechanical buttons. The display devices with a touch detection function, which include such touch panels, do not require input devices such as a keyboard, a mouse, and a keypad, and the use of the display devices tends to increase in portable information devices such as cellular phones as well as in computers.
Types of a touch detection method include several types such as an optical type, a resistive type, and a capacitance type. When touch detection devices of the capacitance type are used in mobile devices and the like, devices having relatively simple structures and low power consumption can be provided. For example, in Japanese Patent Application Laid-open Publication No. 2012-048295 (JP-A-2012-048295), a capacitive touch detection device is disclosed.
In the capacitive touch detection devices, capacitance is formed between a drive electrode and a touch detection electrode and varies in accordance with an external proximity object which approaches from the outside. These display devices use the variation in capacitance and analyze a touch detection signal which appears in the touch detection electrode when a touch detection driving signal is applied to the drive electrode to detect the external proximity object.
In the display devices with a touch detection function in which a display function and a touch detection function are integrated with each other, for example, a touch detection operation may affect display. In contrast, the display device with a touch detection function disclosed in JP-A-2012-048295 detects a touch in a touch detection operation period different from a display operation period, that is, an idle period in which display is stopped between display operations. Therefore, it is possible to reduce the influence of the touch detection operation on the display operation.
However, when the touch detection driving signal is applied to the drive electrode, the potential of the common electrode for display may be varied. For example, in the display device, when the common electrode for display is also used as one of a pair of electrodes for touch sensing and the other electrode (touch detection electrode) is arranged so as to form capacitance together with the common electrode, a variation in the potential of the common electrode for display may increase. Accordingly, in the idle period in which display is stopped between the display operations, a variation in the potential of the common electrode for display becomes the noise of a scanning line due to the capacitance between the common electrode for display and the scanning line, and the noise may cause a leakage current.
In addition, some display devices without a touch detection function perform, in the idle period in which display is stopped between the display operations, a driving operation other than a display driving operation, such as a drive operation in which the potential of the common electrode for display varies. In this case, similarly, in the idle period, the variation in the potential of the common electrode for display becomes the noise of a scanning line due to the capacitance between the common electrode for display and the scanning line, and the noise may cause a leakage current.
In order to suppress the influence of the noise of the scanning line due to the variation in the potential of the common electrode for display, it is effective that a first gate driver and a second gate driver which are arranged such that the scanning lines are interposed therebetween in the extension direction of the scanning lines may select each row of pixels in a display region from both ends of the scanning lines. However, transistor elements of the first and second gate drivers need to be provided in a frame which does not contribute to the display region. In this case, the size of the frame may increase. When the size of the frame increases, the space of the display region of the display device is limited. Therefore, it is necessary to reduce the number of transistor elements of the first and second gate drivers in the display device.
For the foregoing reasons, there is a need for a display device, a method of driving the display device, and an electronic apparatus that suppress the noise of a scanning line while suppressing the increase in size of a frame.