Patent Application
20060066236
The present invention relates to a double-sided display panel and a method of manufacturing the same, also relates to an electronic apparatus mounting the double-sided display panel.
The present application claims priority from Japanese Application No. 2004-277012, the disclosure of which is incorporated herein by reference.
In recent years, there have been developed various kinds of self-emission type flat panel display devices such as organic EL (Electroluminescent) display device, PDP (Plasma Display Panel) device, and FED (Field Emission Display) device. These display devices are each formed by arranging self-emission elements on a support substrate so as to form a display unit, and have attracted considerable public attention since they need a small power consumption and can be made thinner than a liquid crystal display which requires a back light.
Moreover, each of these self-emission type flat panel display devices is formed by bonding together two support substrates each having a light emission surface facing outside, so that a double-sided display panel is formed which is capable of displaying picture on both the front side and back side thereof. Japanese Unexamined Patent Application Publication No. 2004-14316 discloses a double-sided display panel consisting of an organic EL display panel. However, since an organic EL display panel becomes deteriorated in its display performance once its organic EL devices formed on its support substrate are exposed to an outside air containing moisture, it is necessary to adopt a sealing structure for shielding the organic EL devices from the outside air. On the other hand, as discussed above in relation to prior art, a pair of support substrates consisting of transparent substrates carrying organic EL devices formed thereon are bonded together through their surfaces on which organic EL devices have been formed, thereby sealing the organic EL devices between the pair of support substrates, thus forming display surfaces facing in mutually opposite directions on the outside surfaces of the two support substrates and thus realizing a double-sided display.
In a self-emission type display device such as an organic EL display device mentioned above, since it is required to connect some driving circuit parts or a wiring board for supplying driving signals to self-emission element section, an actual structure in use is formed in a manner such that signal wires are led from the self-emission element section located within the sealing structure so as to form a lead wire section, thus forming a structure for electrically connecting the lead wire section with a connecting section such as the driving circuit parts or the wiring board.
However, as described above, with regard to a double-sided display panel formed by bonding together two support substrates each carrying a self-emission element section through the surfaces mounting the self-emission element sections, the lead wire sections on two support substrates are bonded to face in different directions in a manner such that the lead wire section on one support substrate will not be overlapped with the lead wire section on the other. As a result, since the lead wire sections are projecting indifferent directions, the total area of an entire display panel becomes larger and thus the display panel requires a larger space for setting the same, hence rendering it impossible to satisfy a space-saving requirement when mounting the display panel into a miniaturized electronic apparatus.
Moreover, in a structure where two lead wire sections are projecting in different directions on two support structures, it is necessary to provide more driving circuit parts or a plurality of wiring boards, or to provide an enlarged wiring board corresponding to the above-mentioned different directions. Consequently, an internal space within an electronic apparatus is excessively occupied by the display panel due to the increased driving circuit parts and the enlarged wiring board, hence rendering it impossible to satisfy a space-saving requirement.
On the other hand, if the lead wire sections to be formed on end portions of support substrates are orientated in the same direction, when one lead wire section is being connected to the driving circuit parts or wiring board, the other lead wire section can cause an interference which makes connecting operation difficult. In particular, since two support substrates are bonded to each other in an extremely narrow interval, it is extremely difficult to carry out an operation of connecting the driving circuit parts or wiring board to lead wire sections formed on the substrate surfaces facing each other.
Besides, since two lead wire sections formed on the respective support substrates are formed on different surfaces facing each other, it is necessary to provide two sets of driving circuit parts or two wiring boards to effect electric connections with the respective lead wire sections, or alternatively, it is necessary to provide a wiring board capable of double-sided connections which is usually extremely expensive, hence causing an increase in the cost of electronic parts. Further, since the two lead wire sections are formed on different surfaces facing each other, it is necessary to carry out several connecting operations such as thermo pressure-bonding to form the electric connections with the respective lead wire sections, hence causing an increase in the manufacturing cost.
The present invention has been accomplished to solve the afore-mentioned problem and it is an object of the present invention to provide an improved double-sided display panel formed by bonding together a pair of support substrates each having a self-emission element section formed on one side thereof and a display surface on the other by taking out light through each support substrate, in a manner such that the display surfaces are facing in mutually opposite directions, followed by forming a sealing space for sealing up the self-emission element sections between the pair of support substrates. Specifically, the present invention is to make it possible to easily connect the lead wire sections formed on the end portions of the support substrates with the driving circuit parts or the wiring board, to save a space required in setting the double-sided display panel or a space required in setting an entire module including the driving circuit parts and the wiring board, and to include connection objects such as the driving circuit parts or the wiring board into one module, thereby reducing the cost of parts and the cost of manufacturing process.
In order to achieve the foregoing objects, a double-sided display panel, a method of manufacturing the same, and an electronic apparatus mounting the double-sided display panel according to the present invention are characterized in the following aspects.
In one aspect of the present invention, there is provided a double-sided display panel formed by bonding together a pair of support substrates each having a self-emission element section formed on one side thereof and a display surface formed on the other by taking out light through each support substrate, in a manner such that the display surfaces are facing in mutually opposite directions, followed by forming a sealing space for sealing up the self-emission element sections between the pair of support substrates. Specifically, lead wires for leading signal wires from the sealing space are formed on at least one of the pair of support substrates, a signal connection member for connecting signal wires formed on the pair of support substrates is formed between the pair of support substrates, so that electric signals can be supplied from one support substrate carrying the lead wires formed thereon to the self-emission element section formed on the other support substrate through the signal connection member.
In another aspect of the present invention, there is provided a method of manufacturing a double-sided display panel formed by bonding together a pair of support substrates each having a self-emission element section formed on one side thereof and a display surface formed on the other by taking out light through each support substrate, in a manner such that the display surfaces are facing in mutually opposite directions, followed by forming a sealing space for sealing up the self-emission element sections between the pair of support substrates. In this method, lead wires for leading signal wires from the sealing space are formed on at least one of the pair of support substrates, a signal connection member for connecting signal wires formed on the pair of support substrates is formed between the support substrates. In particular, when bonding together the two support substrates, the signal connection member is pressure-bonded between the pair of support substrates, in a manner such that electric signals can be supplied from one support substrate carrying the lead wires formed thereon to the self-emission element section formed on the other support substrate through the signal connection member.
These and other objects and advantages of the present invention will become clear from the following description with reference to the accompanying drawings, wherein:
In the following, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Lead wires 14 for leading signal wires from the sealing space 12 are formed on at least one of the two support substrates 10A and 10B, while signal connection member 15 for connecting signal wires formed on the pair of support substrates 10A, 10B is formed between the pair of support substrates 10A and 10B, thereby supplying electric signals through the signal connection member 15 from one support substrate 10A carrying the lead wires 14 formed thereon to the self-emission element section 11B. That is, in the illustrated embodiment, a connecting portion of a flexible wiring board 21 is pressure-bonded to signal wires such as the lead wires 14 formed on the support substrate 10A, so that signals from a circuit board 20 can be supplied through the flexible wiring board 21 to the self-emission element section 11B on the support substrate 10B.
The signal connection member 15, as shown in
A method of manufacturing the double-sided display panel 1 according to the present embodiment will be described as follows. Namely, at first, a pretreatment is carried out to form the lead wires 14 and 18 or the signal wires 17 on the respective support substrates 10A and 10B, followed by forming the self-emission element sections 11A and 11B on the respective support substrates 10A and 10B. Afterwards, one or both of the support substrates 10A and 10B are coated with the sealing member 13 in a manner such that the self-emission element sections 11A and 11B are surrounded by the sealing member. Meanwhile, the signal connection member 15 is arranged on the predetermined positions of the support substrates 10A and 10B.
Subsequently, the two support substrates 10A, 10B are bonded to each other to form the sealing space 12 by virtue of the sealing member 13, while the signal connection member 15 is pressure-bonded between the two support substrates 10A, 10B during the bonding, in a manner such that electric signals can be supplied from the support substrate 10A carrying the lead wires 14 formed thereon to the self-emission element section 11B formed on the support substrate 10B through the signal connection member 15.
Using the double-sided display panel 1 formed in the present embodiment, it is possible to perform a double-sided displaying by virtue of the display surfaces DA and DB formed by virtue of the two self-emission element sections 11A and 11B. On the other hand, since the two self-emission element sections 11A and 11B are sealed within the sealing space 12 formed between the support substrates 10A and 10B, it is possible to save space in the thickness direction as compared with an example in which each of the self-emission element sections 11A and 11B is provided with one sealing space.
Further, the lead wires 14 for leading signal wires from the sealing space 12 are formed on at least one of the pair of support substrates 10A and 10B, while the signal connection member 15 connecting the signal wires respectively formed on the pair of support substrates 10A and 10B is formed between the support substrates 10A and 10B, so that electric signals can be supplied from the support substrate 10A carrying the lead wires 14 formed thereon to the self-emission element section 11B formed on the support substrate 10B through the signal connection member 15. Therefore, it is possible to supply signals from one support substrate 10A to the two self-emission element sections 11A and 11B.
In this way, the lead wire sections for supplying signals to the self-emission element sections 11A and 11B are required to be provided in only one support substrate 10A, making it possible to reduce an area occupied by an entire display panel as compared to an example in which two lead wire sections are projecting in different directions. Further, since it is allowed to perform only one operation of pressure-bonding to connect the lead wire sections to the circuit board (as with a display panel having one self-emission element section), it is possible to realize a double-sided display panel which involves only a simplified step of mounting the circuit board and the like. Moreover, since the circuit board and the like to be connected for supplying signals to the two self-emission element sections 11A and 11B can be made into an integral body, it becomes possible to reduce the cost of parts and to reduce an area occupied for setting a display panel containing mounted parts such as circuit board. In addition, since it is allowed to carry out only one step for connecting circuit board to the lead wire sections, it is possible to reduce the cost of manufacturing process and realize an increased productivity.
Specifically, as shown in
Furthermore, as the signal connection member 15 it is allowed to use an anisotropic conductive elastic member formed by aligning a plurality of conductors 15a in a specific direction and burying the same in an elastic body 15b. Then, when the pair of the support substrates 10A and 10B are bonded to each other, it is allowed to use a bonding-together step to form a sealing space 12, thereby making it possible to pressure-bond the signal connection member 15 in position, thus effecting an easy attachment of the signal connection member 15 without increasing other steps.
Preferably, part of the conductor 15a in the signal connection member 15 mentioned above or one of the foregoing signal wires is formed of gold (Au). By using gold, contact resistance can be reduced, and it is possible to ensure the desired connection without being affected by secular change. Further, as to the signal wires, it is also possible to use a material formed by laminating a low-resistant metal or an alloy such as chromium on ITO. Besides, since an adhesion between ITO and gold is not so satisfactory, it is preferable to interpose a nickel film between ITO and gold film when laminating gold on ITO.
Next, description will be given to explain a more detailed embodiment of the present invention.
Then, a connecting portion of a flexible wiring board 121 is connected to the support substrate 100A carrying lead wires (not shown) formed thereon, while a signal connection member 105 for connecting signal wires (not shown) formed on the support substrates 100A and 100B is formed between the support substrates 100A and 100B. In this embodiment, the signal connection member 105 is formed along an edge different from the edge of the support substrate 100A connected with the flexible wiring board 121 (the width of the signal connection member 105 is appropriately set in response to signal wires to be connected). However, the present invention should not be limited by this. In fact, it is also possible for the signal connection member 105 to be formed along the edge of the support substrate 100A connected with the flexible wiring board 121 in a manner as described in the foregoing embodiments. Besides, although there has been shown an example in which the signal connection member 105 is formed on the inner side of the sealing member 103, this should not form any limitation to the present invention. Actually, it is also possible for the signal connection member 105 to be formed on the outside of the sealing member 103.
The present embodiment represents COF structure (Chip On Film) in which driver IC chip (semiconductor circuit chip containing driver) is mounted on the flexible wiring board 121, thus forming an arrangement in which the self-emission element sections 101A and 101B are driven by the driver IC chip 120.
Moreover, with respect to the self-emission element section 101A there are formed signal wires for supplying scan selection driving signal S2 from the driver IC chip 120 to the electrodes arranged in y direction. Actually, the scan selection driving signal S2 is supplied to the self-emission element section 101A through the foregoing signal wires, and also supplied to the electrodes arranged in y direction of the self-emission element section 101B through the signal wires branching from the foregoing signal wires and passing through the signal connection member 105.
By virtue of the signal wires shown in
Further, with respect to the self-emission element section 101A there are formed signal wires for supplying scan selection driving signal S2 from the driver IC chip 120 to the electrodes arranged in y direction. Actually, the scan selection driving signal S2 is supplied to the self-emission element section 101A through the foregoing signal wires, and also supplied to the electrodes arranged in y direction of the self-emission element section 101B through the signal wires branching from the foregoing signal wires and formed through the signal connection member 105.
By virtue of the signal wires shown in
In this way, similar to the example shown in
On the other hand, the signal wires for supplying the scan selection signal S5 are branching on the support substrate 101A, and there are formed signal wires for inputting the scan selection signal S5 to the scanning driver 201b on the support substrate 100B by way of the signal connection member 105. Further, there are formed signal wires for supplying scan selection driving signal S2 from the scan driver 201b to the electrodes arranged in y direction of the self-emission element section 101B.
Moreover, the data driving signal S1 is supplied to the self-emission element section 101A through the above-mentioned signal wires, and also supplied to the electrodes arranged in x direction of the self-emission element section 101B on the support substrate 100B, by way of the signal wires extending from the self-emission element section 101A and passing through the signal connection member 105. Then, the self-emission element sections 101A and 101B are driven by the data driving signal S1 and the scan selection driving signal S2 outputted from the scan drivers 201a and 201b.
An example shown in
As shown in
As shown, each self-emission element section are formed by interposing an organic layer 33 containing an organic luminescent layer between first electrodes 31 on one hand and second electrodes 32 on the other, thereby forming a plurality of organic EL devices on the support substrates 100A (100B). In an example shown in
Then, the end portions 32a of the second electrodes 32 are connected with the lead wires 41 or the signal wires 51 within the sealing space 102. The lead wires 41 or signal wires 51 are such that the first electrode layers 41a and 51a formed by the same material and the same process as the first electrodes 31 are insulated by an insulating layer 34 from the first electrodes 31 and patterned as such, while the second electrode layers 41b and 51b forming low-resistant wiring portions containing gold or silver are formed on the first electrode layers 41a and 51a. Here, although there have been shown self-emission element sections with a prerequisite that they are all driven in a passive driving manner, it is also possible to form self-emission element sections driven in an active driving manner.
The signal connection member 105 connecting the lead wires 41 with the signal wires 51 is pressure-bonded between the support substrates 100A and 100B. In this way, electric signals supplied from a circuit board (not shown) connected with the lead wires 41 on the support substrate 100A can be supplied to the self-emission element section on the support substrate 100B by way of the signal connection member 105.
In such an embodiment, each of the support substrates 100A and 100B is preferred to be a flat plate or a film layer having a transparency and made of glass or plastic.
Although the organic layer 33 is formed by a combination including a hole transporting layer 33a, a luminescent layer 33b, and an electron transporting layer 33c, each of the hole transporting layer 33a, the luminescent layer 33b, and the electron transporting layer 33c may be not only one layer, but also several layers. Moreover, it is also possible to dispense with the hole transporting layer 33a and/or the electron transporting layer 33c. Further, if necessary, it is allowed to insert other organic layers including a hole injection layer, an electron injection layer and a hole blocking layer. Here, the hole transporting layer 33a, the luminescent layer 33b, and the electron transporting layer 33c can be formed by any conventional materials (it is allowed to use either a high molecular material or a low molecular material).
With regard to a luminescent material for forming the luminescent layer 33b, it is allowed to make use of a material presenting a luminescence (fluorescence) when the material returns from a singlet excited state to abase state, or a material presenting a luminescence (phosphorescence) when it returns from a triplet excited state to a base state by way of the singlet excited state.
An adhesive agent forming the sealing member 103 may be a thermal-setting type, a chemical-setting type (2-liquid mixture), or a light (ultraviolet) setting type, which can be formed by an acryl resin, an epoxy resin, a polyester, a polyolefine. Particularly, it is preferable to use an ultraviolet-setting epoxy resin adhesive agent which is quick to solidify without a heating treatment.
Moreover, in the present embodiment, the self-emission element sections consisting of organic EL devices may be a single color display or a multi-color display. In practice, in order to realize a multi-color display, it is allowed to adopt a discriminative painting method or a method in which a single color (white or blue) luminescence functional layer is combined with a color conversion layer formed by a color filter or a fluorescent material (CF manner, CCM manner), a photograph breeching method which realizes a multiple light emission by emitting an electromagnetic wave or the like to the light emission area of a single color luminescent functional layer, or SOLED (transparent Stacked OLED) method in which two or more colors of unit display areas are laminated to form one unit display area.
According to the foregoing embodiments and examples, with regard to a double-sided display panel having a sealing space for sealing up self-emission element sections between a pair of support substrates, it is possible to easily connect lead wire sections formed on the end portions of the support substrates with driving circuit parts or a wiring board, to save a space required in setting the double-sided display panel or a space required in setting an entire module including the driving circuit parts and the wiring board, and to include connection objects such as the driving circuit parts or the wiring board into one module, thereby reducing, the cost of parts and the cost of manufacturing process.
The double-sided display panels according to the above-described embodiments or examples can be installed in portable information terminals such as cellular phone and PDA (Personal Digital Assistant), as well as in electronic apparatus including various display devices, thereby making it possible to reduce the size and weight of electronic apparatuses, thereby realizing a reduced manufacturing cost.
While there has been described what are at present considered to be preferred embodiments of the present invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-277012 | Sep 2004 | JP | national |
