1. Field of the Invention
This invention relates to a display apparatus, a layout method for a display apparatus and an electronic apparatus, and more particularly to a display apparatus of the flat type wherein a plurality of pixel circuits each including a light emitting portion are arrayed two-dimensionally in rows and columns or in a matrix, a layout method for the display apparatus, and an electronic apparatus including the display apparatus.
2. Description of the Related Art
In recent years, in the field of display apparatus for displaying an image, a display apparatus of the flat type or flat panel type wherein a plurality of pixel circuits, which may be hereinafter referred to sometimes as pixels, are arrayed or disposed in rows and columns has spread rapidly. As one of such flat type display apparatus, a display apparatus is available wherein an electro-optical element of the current driven type whose emitted light luminance varies in response to the value of current flowing to the element is used as a light emitting portion or element of a pixel. As the electro-optical element of the current driven type, an organic EL element is known which is formed from electroluminescence of an organic material and utilizes a phenomenon that an organic thin film emits light when an electric field is applied thereto.
An organic EL display apparatus which uses an organic EL element as a light emitting portion of a pixel has the following characteristics. In particular, the power consumption of the organic EL display apparatus is low because the organic EL element can be driven by an application voltage lower than 10 V. Since the organic EL element is a self-luminous element, the organic EL display apparatus displays an image of observability higher than that of a liquid crystal display apparatus. Besides, since an illumination member such as a backlight is not required, reduction in weight and thickness of the organic EL display apparatus can be implemented readily. Further, since the organic EL element operates at a very high response speed of approximately several microseconds, an after-image upon display of a dynamic picture image does not appear.
A flat type display apparatus such as an organic EL display apparatus or a liquid crystal display apparatus can adopt a passive matrix driving method and an active matrix driving method as a driving method thereof. A display apparatus of the active matrix type from between the two types can be implemented readily as a large-size high-definition display apparatus because the electro-optical element continues light emission over a period of one display frame. In a display apparatus of the active matrix type, current to flow to the electro-optical element is controlled by an active element such as, for example, an insulated gate type field effect transistor provided in a pixel in which the electro-optical element is provided. As the insulated gate type field effect transistor, generally a TFT (Thin Film Transistor) is used.
Incidentally, in a flat type display apparatus such as an organic EL display apparatus or a liquid crystal display apparatus, a pixel array section wherein pixels are arrayed in a matrix sometimes adopts a layout structure wherein two signal lines connected to pixel circuits belonging to two pixel columns neighboring with each other are wired in a neighboring relationship with each other. As one of layout structures of the type just described, for example, a structure is known wherein pixel circuits in an odd-numbered column and pixel circuits in an even-numbered column neighboring with each other across an axis of a column direction of a matrix pixel array are laid out symmetrically with each other with respect to the axis of the column direction.
In the following description, the structure wherein pixel circuits in an odd-numbered column and pixel circuits in an even-numbered column neighboring with each other across an axis of a column direction of a matrix pixel array are laid out symmetrically with each other with respect to the axis of the column direction is referred to as mirror type layout structure. The mirror type layout structure is advantageous in that efficient layout of the pixel array section can be anticipated and the degree of freedom is enhanced.
However, in the case where the mirror type layout structure is adopted, signal lines extending in the direction of a column sometimes neighbor with each other between pixel circuits of an odd-numbered column and an even-numbered column. Therefore, in order to prevent parasitic capacitance from existing between the signal lines neighboring with each other, a shield line is wired between the signal lines neighboring with each other as disclosed, for example, in Japanese Patent Laid-Open No. 2005-338592.
On the other hand, a flat type display apparatus such as an organic EL display apparatus or a liquid crystal display apparatus is known which adopts a selector driving method in order to achieve reduction of the number of outputs of a driving section for supplying display signals to a display panel from the outside of the display panel. A flat type display apparatus of the type described is disclosed, for example, in Japanese Patent Laid-Open No. 2002-032051. The selector driving method is sometimes called time-divisional driving method.
In the selector driving method, a plurality of signal lines from among signal lines on a display panel are allocated as a unit or group to one output of a driving section outside the display panel to carry out driving such that display signals outputted in a time series from the driving section are distributed time-divisionally to the plural signal lines by means of a selector circuit. The selector driving method is advantageous in that, in the case where the number of signals to make a unit is, for example, three, the number of outputs of the driving section outside the display panel can be reduced to ⅓ with respect to the total number of signal lines on the display panel.