Electric lamp and discharge devices – With luminescent solid or liquid material – Solid-state type
Reexamination Certificate
2002-03-19
2004-06-01
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Solid-state type
C313S505000, C313S590000, C345S058000, C257S083000, C445S024000, C438S020000
Reexamination Certificate
active
06744198
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods for manufacturing display devices that include light-emitting elements, such as electroluminescent (hereinafter referred to as EL) elements and LED (light emitting diode) elements, and to display devices manufactured in accordance with these methods.
2. Description of Related Art
In active matrix displays using current-controlled light-emitting elements, such as organic EL elements and LED elements, such light-emitting elements emit light by themselves. Therefore, unlike liquid crystal displays, these active matrix displays do not need any backlight, and provide advantages including visibility that is less dependent upon angle.
In these display devices, generally, a plurality of light-emitting elements are arrayed in a matrix. Adjacent light-emitting elements are separated by an insulative, light-shielding protrusion referred to as a bank layer.
In order to form the display devices, a liquid material for forming a hole injection layer, and a liquid material for forming an organic EL layer or an organic semiconductive layer, are discharged, by, for example, an ink-jet method, into compartments separated by bank layers, that is, into pixels, to deposit a hole injection layer and an organic EL layer or an organic semiconductive layer in the compartments. This protruding bank layer prevents the precursors for these layers from extending into adjacent compartments when the precursors are discharged.
In addition, this light-shielding bank layer prevents light from passing through gaps between pixels, and colors from being mixed with each other between the adjacent pixels, and thus increases the contrast ratio when a completed display device is operated.
On the other hand, boundary areas between the light-emitting elements have driving elements, such as thin-film transistors (hereinafter referred to as TFT), for driving the light-emitting elements and various wires connected to the driving elements. The wires are formed of, for example, aluminum or the like. In addition, these boundary areas are provided with a light-shielding layer for preventing the TFTs from generating an optical leakage current.
SUMMARY OF THE INVENTION
The present invention is directed to a method for manufacturing a display device that includes a light-transmitting substrate and, above the light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements connected to the light-emitting elements, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and wires connected to the driving elements. The method includes the steps of: forming the wires on the light-transmitting substrate by patterning a light-shielding, conductive layer so as to have a shape in plan view corresponding to the shape of the bank layer in plan view; forming the bank layer by self-aligning above the wires on the substrate by exposing the wires, acting as a mask, from the rear surface of the substrate; and forming the light-emitting elements in the areas surrounded by the bank layer.
The present invention is also directed to a method for manufacturing a display device that includes a light-transmitting substrate and, above the light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements connected to the light-emitting elements, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and a light-shielding layer to shield at least part of the driving elements from light. The method includes the steps of: forming the light-shielding layer on the light-transmitting substrate by patterning a shape in plan view corresponding to the shape of the bank layer in plan view; forming the bank layer by self-aligning above the light-shielding layer on the substrate by exposing the light-shielding layer, acting as a mask, from the rear surface of the substrate; and forming the light-emitting elements in the areas surrounded by the bank layer.
A display device according to the present invention includes, above a light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements, each being connected to the corresponding light-emitting element, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and wires formed of a light-shielding, conductive film connected to the driving elements. The wires above the substrate act as a mask while being subjected to light exposure from the rear surface of the substrate to form the bank layer above the wires by self-aligning.
A display device according to the present invention includes, above a light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements, each being connected to the corresponding light-emitting element, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and wires formed of a light-shielding, conductive film connected to the driving elements. At least part of the wires has a shape in plan view corresponding to the shape of the bank layer in plan view.
A display device according to the present invention includes, above a light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements, each being connected to the corresponding light-emitting element, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and a light-shielding layer to shield at least part of the driving elements from light. The light-shielding layer above the substrate acts as a mask while being subjected to light exposure from the rear surface of the substrate to form the bank layer above the light-shielding layer by self-aligning.
A display device according to the present invention includes, above a light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements, each being connected to the corresponding light-emitting element, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and a light-shielding layer to shield at least part of the driving elements from light. The light-shielding layer has a shape in plan view corresponding to the shape of the bank layer in plan view.
An electronic apparatus according to the present invention includes a display device described above.
Cost reduction in manufacturing and enhancement of image quality, which are typical requirements for display devices, are strongly desired in the display devices discussed above, as well as in other display devices.
In the related art manufacturing method discussed above, unfortunately, a dedicated photomask must be used to form a bank layer. The manufacturing cost, therefore, increases due to the formation of the bank layer.
In addition, using the dedicated photomask to form the bank layer of the display devices in the related art method reduces and varies the aperture ratio in pixels according to the alignment accuracy between the various light-shielding wires or the driving elements and the bank layer, which consequently makes it difficult to display bright and high-quality images.
Considering the above-described problems, the present invention provides a method for manufacturing a display device in which the manufacturing cost is reduced, and which ensures a high aperture ratio and a reduced variation of aperture ratios in pixels. The invention also provides a display device that is capable of displaying bright and high-quality images.
A first method for manufacturing a display device according to an embodiment of the present invention is a method for manufacturing a display device that includes a light-transmitting substrate and, above the light-transmitting substrate, a plurality of light-emitting elements arrayed in a plane, driving elements connected to the light-emitting elements, a bank layer disposed in the boundary areas between the plurality of light-emitting elements, and wires c
Oliff & Berridg,e PLC
Patel Ashok
Seiko Epson Corporation
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