BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display apparatus, a manufacturing method of a display apparatus, and an electronic device, and more particularly, to a display apparatus, a manufacturing method of a display apparatus, and an electronic device each of which is configured not to give adverse influences of processing in the fabrication sequence to the electrode surfaces of pixels.

2. Description of the Related Art

An organic EL (Electro Luminescence) panel displays a video by supplying a current to respective pixels each having a vapor deposited organic electroluminescence layer or the like from the side or top or bottom of the panel by way of metal wires as is described, for example, in JP-A-2008-257086. When an organic EL panel becomes larger, necessary luminance of pixels increases and so does a current to be supplied. Also, because one wire becomes longer, wiring resistance becomes higher, which makes a voltage drop from the current supply end larger.

This voltage drop raises problems, such as the occurrence of non-uniform luminance and an increase of power consumption. Accordingly, a low resistance material is used for the current supply metal layer with the aim at suppressing a voltage drop. Examples of a low resistance metal include but not limited to aluminum (Al), copper (Cu), gold (Au), and silver (Ag). Of these candidates, Cu has a problem that it is quite difficult to form a wire from Cu whereas Au and Ag have a problem that they are expensive. In view of the foregoing, Al is often used as metal for low resistance wires.

Al can be processed by either wet etching or dry etching and is inexpensive. In a case where a single-layer Al wire is used, however, there is a concern about the generation of defects, such as hillock and spike.

The term, “hillock”, referred to herein means a semispherical protrusion generated on the wire surface due to heat history in the fabrication process. The term, “spike”, referred to herein means a phenomenon that Al enters into silicon (Si) when Al is subjected to heat treatment while in contact with Si.

As a countermeasure against these defects, there is a laminated structure to sandwich an Al wire between heat-resistant high melting point metal. As a consequence, a metal layer aimed at anti-hillock and anti-spike appears on the surface of the top metal layer when Al is used as a current supply metal layer.

A current flown through the current supply metal layer is injected into an organic electroluminescence layer by way of electrodes of pixels. It is therefore necessary for the electrodes of pixels to have a characteristic that they are capable of injecting a current into the organic electroluminescence layer. Normally, ITO (Indium Tin Oxide) having a high work function is used as a hole injecting electrode. As a consequence, metal with a high capability of injecting holes into the organic electroluminescence layer appears on the surface of a metal layer used as the electrodes of pixels.

SUMMARY OF THE INVENTION

An insulating film (opening defining insulating film) defining openings of pixels is formed by the steps of applying photosensitive resin followed by exposure and peeling (development). When the opening defining insulating film is peeled, pad portions for connecting anode electrodes and external wires (for example, flexible cables) are soaked in a peeling liquid at the same time. A battery corrosion reaction thus takes place and the surface nature of the anode electrodes is deteriorated. Deterioration of the surface nature of the anode electrodes lowers the reflectance, which in turn lowers the luminance of pixels.

Thus, it is desirable to provide a technique of preventing adverse influences of processing in the fabrication sequence from being given to electrodes of pixels.

According to an embodiment of the present invention, there is provided a display apparatus including a display region provided with a plurality of pixel portions, wires installed to the respective pixel portions within the display region from an outside of the display region and transmitting a signal to drive the respective pixel portions, connection pads provided on the outside of the display region and serving as input portions that provide the wires with a signal while electrically conducting with the wires, switch elements provided on the outside of the display region in a middle of the wires, and a light shielding covering portion shielding the switch elements from light and formed to cover the connection pads while electrically conducting with the connection pads.

According to another embodiment of the present invention, there is provided an electronic device having a main body casing provided with the display apparatus configured as above.

According to the embodiments of the present invention, the light shielding covering portion that shields the switch elements from light is provided to cover the connection pads while electrically conducting with the connection pads that electrically conduct with the wires. It is therefore possible to protect the surfaces of the connection pads with the light shielding covering portion.

In a case where the pixel portion includes an organic electroluminescence layer interposed between the anode electrode and the cathode electrode, by making the light shielding covering portion out of the same material as the anode electrode, it becomes possible to prevent the battery effect from being generated in the developing step carried out while the anode electrode is in an exposed state.

According to still another embodiment of the present invention, there is provided a manufacturing method of a display apparatus including the steps of forming transistors for each pixel on a substrate, covering the transistors with a first insulating film and planarizing a surface of the first insulating film, forming a second insulating film defining openings of respective pixels between every two adjacent pixels on the first insulating film, forming anode electrodes in the openings of the respective pixels defined by the second insulating film, forming an organic electroluminescence layer on the anode electrodes, and forming a cathode electrode on the electroluminescence layer.

According to this embodiment of the present invention, the second insulating film that defines openings of the respective pixels is formed first and thence the anode electrodes are formed in the openings. It thus becomes possible to prevent the influences in the step of forming the second insulating film from being given to the anode electrodes.

According to the embodiments of the present invention, it becomes possible to prevent the adverse influences of the processing in the fabrication sequence from being given to the electrodes of pixels, which can in turn prevent deterioration of the display performance of the pixels.

