KR100946231B1 - Active matrix electroluminescent display devices, and their manufacture - Google Patents

Abstract

Physical barriers (210) are presented between neighbouring pixels (200) on a circuit substrate (100) of an active-matrix electroluminescent display device, particularly with LEDs (25) of organic semiconductor materials. The invention forms these barriers (210) with metal or other electrically-conductive material (240), that is insulated (40) from the LEDs but connected to the circuitry within the substrate (100). This conductive barrier material (240) backs-up or replaces at least a part of the drive supply line (140, 240) to which the LEDs are connected by a drive element T1. This transfers the problem of line resistance and associated voltage drop from within the circuit substrate (100), where it is severely constrained, to the much freer environment of the pixel barriers (210) on the substrate (100) where the conductive barrier material (240) can provide much lower resistance. Very large displays can be made with low voltage drops along this composite drive supply line (140, 240). Furthermore, the structure can be optimised to form a smoothing capacitor (Cs) between this drive supply line (140, 240) with its conductive barrier material (240) and the further supply line (230) of the LED upper electrodes (23) extending on an insulating coating (40) over the top of the conductive barrier material (240).

Description

ACTIVE MATRIX ELECTROLUMINESCENT DISPLAY DEVICES, AND THEIR MANUFACTURE}

FIELD OF THE INVENTION The present invention relates to active-matrix electroluminescent display devices, in particular using, but not limited to, light emitting diodes made of semiconductor conjugated polymers or other organic semiconductor materials. The invention also relates to a method of manufacturing such a device.

Such active-matrix electroluminescent display devices are known, which include an array of pixels residing on a circuit board, where each pixel generally comprises a current-driven electroluminescent element of organic semiconductor material.

In many such arrays, a physical barrier of insulating material exists between neighboring pixels in at least one direction of the array. Examples of such barriers are published British patent application GB-A-2 347 017, published PCT patent application WO-A1-99 / 43031, published European patent application EP-A-0 895 219, EP-A-1 096 568, and EP-A-1 102 317, the entire contents of these patents are incorporated herein by reference.

Such barriers are often referred to as "walls", "partitions", "banks", "ribs", "separators", or "dams", for example. It is referred to. As can be seen from the cited references, the barrier can provide several functions. The barrier can be used to define an electroluminescent layer and / or an electrode layer of individual pixels and / or rows of pixels during manufacture. Thus, for example, the barrier prevents pixel overflow of conjugate polymer material that can be inkjet printed on red, green, and blue pixels of a color display or spin-coated for monochrome displays. Barriers in the manufactured device can provide well-defined optical separation of pixels. The barrier can also carry or include a conductive material (such as the top electrode material of the electroluminescent element) as an auxiliary line for reducing the resistance of the common top electrode of the electroluminescent element (and thus the voltage drop across it).

Each electroluminescent element of an active-matrix display device is connected in series with a drive element (generally referred to as a thin film transistor, hereinafter "TFT") between two voltage supply lines of the array. These two supply lines are generally a power supply line and a ground line (also referred to as a "return line"). In general, light emission from an electroluminescent element such as an LED is controlled by the current flow through the electroluminescent element as changed by each driving element TFT. The supply line, to which the electroluminescent elements are connected by a series of drive elements, may be called the "drive supply line" or "drive line" or "current drive line" of the pixel. Voltage drops along these two supply lines can cause incorrect drive currents for individual pixels. This may result in a decrease in radiation intensity (ie fading of the image) from the pixel at the center of the display. Moreover, for large displays, the effect is so bad that no emission occurs at the center, limiting the acceptable display size.

Several methods have been proposed to reduce such voltage drops and / or effects on rows of pixels. Thus, it is known from published US patent application US-A1-2001 / 0007413 (Philips Control Number: PHGB000001) for reducing the voltage drop along a line by tapering the width of the line. The published PCT patent applications WO-A1-01 / 01383 and WO-A1-01 / 01384 (Philips Control Numbers: PHB34350 and PHB34351) employ other methods in which error values are generated to correct the drive signal for each pixel. . The entire contents of US-A1-2001 / 0007413, WO-A1-01 / 01383 and WO-A1-01 / 01384 are also incorporated herein by reference.

It is an object of the present invention to monitor such voltage drops along a drive supply line and to reduce the device structure, layout and electronics in a manner that does not significantly complicate.

According to one aspect of the invention, an active-matrix electroluminescent display device having the features of claim 1 is provided.

According to the invention, the physical barrier between the pixels consists of a partially and / or mainly electrically-conductive material (usually a metal), which is insulated from the electroluminescent element and provides at least a part of the drive supply line. . Such conductive barrier material may form the conductive core of the barrier. It is connected to the circuit board, the electrode connection for each drive element, via a contact window (hereinafter referred to as "via") between the pixel barrier in the substrate and the drive element. Thus, the problem of line resistance and associated voltage drop is transferred from within the circuit board (severely constrained) to a much more free environment of the pixel barrier on the substrate (where the conductive barrier material can provide lower resistance).

By this means, the electrical resistance along the drive supply line (as a result of the voltage drop) can be greatly reduced compared to the conductor layer in the circuit board, which is for example a thin film electrode line of the drive element. Thus, along this drive line, the conductive barrier material generally has a cross-sectional area that is generally wider (eg, at least 2 times, or even at least 10 times larger) than the cross-sectional area of the thin conductor layer in the circuit board. As such, the resistance (even for long lines) can be low, and very large electroluminescent displays can be constructed in accordance with the present invention. Even in smaller displays, image quality can be improved by the use of conductive barrier materials in accordance with the present invention.

By providing one via per pixel, a continuous barrier line of conductive material on the circuit board can be used to replace a drive line previously incorporated in the circuit board. This allows for an increase in pixel aperture. The conductive barrier line itself may simply overlap with the column or row conductor lines of the array. Alternatively, a line (or individual length) of conductive barrier material can be used to back up that length of the drive line of the circuit board. This alternative provides a greater choice in the number and location of vias.

The design of such a device structure according to the invention can also be optimized to include a smoothing capacitor between the two voltage supply lines of the electroluminescent element. Insulation of the conductive barrier material from the electroluminescent element can form the capacitor dielectric of such a smoothing capacitor. This insulation can be in the form of a coating on the sides and top of the conductive barrier material. In general, the other supply line (for the top electrode of the electroluminescent element) may extend on this insulating coating on top of the conductive barrier material. Thus, a smoothing capacitor for the power source can be easily realized between the drive line comprising the conductive barrier material and the additional supply line including the top electrode of the electroluminescent element.

It is advantageous for the physical barrier to extend as a network of conductive barrier material between pixels in both the row and column directions of the array. Such a network of conductive barrier materials can serve to monitor the resistance between the drive line regions across the array. It can also provide a design option when determining the capacitance value of the smoothing capacitor for the power source of the electroluminescent element.

However, the physical barrier may extend between pixels in only one direction of the array, for example in the column or row direction. In this case, an additional insulated barrier of conductive barrier material may be provided laterally for different purposes, for example to back up the row or column lines. This additional insulated barrier can also be configured to form additional components, for example sustain capacitors in each pixel.

According to another aspect of the invention, there is also provided an advantageous method of manufacturing such an active-matrix electroluminescent display device according to the first aspect. The method,                 

(a) opening a contact window in the intermediate insulating layer on the circuit board to expose the electrode connection to at least some respective drive element of the pixel;

(b) forming a physical barrier on the circuit board with insulation at least on the side of the physical barrier adjacent the pixel region;

(c) providing an electroluminescent element in the pixel region between the physical barriers

Include,

The conductive barrier material is provided by depositing an electrically-conductive material for at least connection in the contact window of the intermediate insulating layer.

Various methods may be advantageously used to deposit and form the barrier material (s) and to insulate the conductive barrier material.

Various advantageous features and feature-combinations according to the invention are described in the appended claims. These and other features are shown in the embodiments of the invention now described by way of example with reference to the accompanying drawings.

1 is a partial cross-sectional view of a pixel array and circuit board of an active-matrix electroluminescent display device (with a conductive barrier forming at least a portion of a drive line) as one particular embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1 taken along line I-I of FIG. 2, showing a plan view of four pixel regions (showing a specific example of layout features for a conductive barrier of such a device in accordance with the present invention).                 

3 is a circuit diagram illustrating such four pixel regions of such a device in accordance with the present invention.

4 is a cross-sectional view of a portion of a pixel array and a circuit board through a holding capacitor in the same and / or other embodiment of an active-matrix display device in accordance with the present invention.

5 is a top view similar to FIG. 2 but showing an example of network layout features for the conductive barrier of the drive line of a further device embodiment in accordance with the present invention;

6 and 7 are top views similar to FIG. 2 but showing two examples of different layout features for the conductive barrier of another device according to the present invention as a backup for the row conductors and the drive lines.

8 and 9 are circuit diagrams for two modified pixel-driven configurations of pixel regions of two further devices according to the present invention.

10-12 are cross-sectional views of device portions, such as the cross section of FIG. 1, in a stage during manufacture in one particular embodiment according to the present invention.

FIG. 13 is a cross sectional view of the device portion at the FIG. 12 stage, showing a variant in the insulation of the conductive barrier of the drive line according to the invention.

14 is a cross-sectional view of another embodiment of a conductive barrier structure using a metal coating to form at least a portion of a drive line according to the present invention.

Figure 15 is a cross-sectional view illustrating side by side barriers with conductive barrier materials that may each be used in different embodiments of the present invention.                 

FIG. 16 is a plan view illustrating lateral multi-barrier layout features that may be used in different embodiments of the present invention. FIG.

17 is a cross-sectional view illustrating a barrier embodiment with multiple conductive components that can be used in different embodiments of the present invention.

It should be noted that all drawings are schematic. The relative dimensions and ratios for the parts of these figures are shown to be enlarged or reduced in size for clarity and convenience in the figures. In general, the same reference numerals are used to refer to corresponding or analogous features in different embodiments.

1 through 4

The active-matrix electroluminescent display device of FIG. 1 includes an array of pixels 200 on a circuit board 100. Each pixel 200 is connected to supply lines 140 and 240 by a current-controlled series drive element T1 (1 to 5) on a circuit board 100 (25) (21). 22, 23). This series element T1, which is typically a TFT, controls the current through the electroluminescent elements 25 (21, 22, 23). As will be explained later, the display can be very large due to the structure of these current drive lines 140, 240 using the conductive barrier material 240 in accordance with the present invention. Apart from this configuration of the drive supply lines 140, 240 according to the invention, the display can be constructed using known device and circuit techniques, for example as in the background reference above.                 

Thus, electroluminescent element 25 generally comprises a light emitting diode (LED) of organic semiconductor material 22 between lower electrode 21 and upper electrode 23. In certain preferred embodiments, semiconductor conjugate polymers may be used in the electroluminescent material 22. For an LED that emits light 250 through the substrate 100, the lower electrode 21 may be an anode of indium tin oxide (ITO), and the upper electrode 23 may comprise, for example, calcium and aluminum. It may be a cathode. 1 shows an LED structure in which the lower electrode 21 is formed as a thin film on the circuit board 100. Subsequently-deposited organic semiconductor material 22 is formed with the thin film electrode layer 21 at the window 12a in the planar insulating layer 12 (for example, made of silicon nitride) extending over the thin film structure of the substrate 100. Contact.

As shown in FIGS. 1 and 3, the LED 25 and the drive element T1 are connected in series between a pair of voltage supply lines 140, 240 and 230. Lines 140 and 240, from which drive element T1 controls the LED connection and hence current flow, are referred to as drive lines. Another line 230 is professionally connected to the LED 25. Thus, in the particular embodiment of FIG. 1, line 230 is formed as a common extension of upper electrode 23 of pixel 200. In the circuit configuration of FIG. 3, line 230 is grounded and forms a return line, while voltage Vdd is applied to lines 140 and 240 as a power supply line.

The series drive element T1 generally includes a TFT formed in the substrate 100 as part of a thin film circuit. Substrate 100 may have an insulating glass base 10 on which an insulating surface-buffer layer 11 of, for example, silicon dioxide is deposited. The thin film circuit is built on the layer 11 in a known manner. Thus, in addition to the TFT T1, the circuit board 100 generally includes other drive and matrix addressing circuits having the thin film elements T2, Ch, 140, 150 and 160, for example, as shown in FIG. . It is to be understood that FIG. 3 illustrates one particular pixel circuit configuration as an example. Other pixel circuit configurations are known for active matrix electroluminescent display devices. It should be readily understood that the present invention can be applied to the pixel barrier of such a device regardless of the particular pixel circuit configuration of the device.

As shown in FIG. 3, the pixel circuit includes an addressing TFT T2 between the lateral set of row (addressing) conductors 150 and column (data) conductors 160, all of which are substrate 100. It is formed on the top. Each row of pixels is addressed again in the frame period by a selection signal applied to the associated row conductor 150 (therefore the gate of the addressing TFT T2 of the pixels of that row). This signal turns on the addressing TFT T2, loading the pixels of the row with each data signal from the column conductor 160. These data signals are applied to the gates of the individual driving TFTs T1 of each pixel. In order to maintain the resultant conduction state of the driving TFT T1, this data signal is held on the gate 5 by a holding capacitor Ch coupled between the gate 5 and the driving lines 140 and 240. . Therefore, the driving current through the LED 25 of each pixel 200 is controlled by the driving TFT T1 based on the driving signal applied during the previous address period and stored as a voltage on the associated capacitor Ch. In the specific example of Fig. 3, T1 is shown as a P-channel TFT, while T2 is shown as an N-channel TFT.

Such circuits can be constructed with known thin film techniques. 1 shows a P-channel TFT (T1), in which the active semiconductor layer 1 (usually made of polysilicon) and the gate dielectric layer 2 (generally made of silicon dioxide) And the P-type of the semiconductor layer 1 through the gate electrode 5 (generally made of aluminum or polysilicon) and through the window (via) in the overlying insulating layer (s) 2 and 8. Metal electrodes 3 and 4 (generally made of aluminum) in contact with the doped source and drain regions. The expansion of these metal electrodes 3 and 4 at the upper level forms an interconnection between the TFT electrode 3 and the lower electrode 21 of the LED, and at least the connection region 140 of the drive lines 140, 240. Form. In certain layout embodiments (such as FIG. 2), this extension of the metal electrodes 4 in a row may form a continuous line 140 for that row. 1 also shows a cross section for address line 150, which may be aluminum or polysilicon, for example, and may be formed from the same layer as TFT gate 5.

The holding capacitor Ch may be formed as a thin film structure in the circuit board 100 in a similarly known manner. 4 shows such a capacitor Ch comprising a thin film conductor plate 155 on a thin film dielectric 2 on a thin film conductive plate 105.

As with known devices, the device (s) of FIGS. 1-4 in accordance with the present invention include a physical barrier 210 between at least some of the neighboring pixels in at least one direction of the array. Such barrier 210 may also be referred to, for example, as “wall”, “partition”, “bank”, “rib”, separator, or “dam.” Depending on the particular device embodiment and its manufacture, Way, for example,

While providing the semiconducting polymer layer 22, preventing separation and overflow of the polymer solution between individual pixels 200 and / or each region of the row of pixels 200,

Provide self-patterning capability on the substrate surface in the confines of the semiconducting polymer or other electroluminescent layer 22 to individual pixels 200 and / or rows of pixels 200 (and perhaps for example top electrode 23). Self-separation of the individual electrodes for the pixels, which are the individual bottom layers);

Serves as a spacer for a mask over the substrate surface during deposition of at least the organic semiconductor material 22 and / or the electrode material,

Can be used to form an opaque barrier 210 for well-defined light separation of pixels 200 in an array when light 250 is emitted through the top (instead of, or in conjunction with, the bottom substrate 100). .

Whatever the specific use in this known manner, in an embodiment of the invention the physical barrier 210 is constructed and used in a special manner. Thus, the pixel barrier 210 provided in accordance with the present invention consists mainly of an electrically-conductive material 240, which is insulated from the LED 25 and is provided with the driving lines 140, 240. Provide at least a portion. Barrier 210 preferably comprises a bulk or core of conductive material 240 that is a metal (for very low resistance, for example aluminum or copper or nickel or silver). The contact window 12b is present in the intermediate insulating layer 12 between the barrier 210 and the substrate circuit. Conductive barrier material 240 is connected to electrode connections 4, 140 for at least some respective drive element T1 of pixel 200 in the vias provided by these windows 12b. As shown in FIG. 1, the source and drain electrodes connect the main current path of the current-controlled driving TFT T1 between the conductive barrier material 240 of the drive line and the lower electrode 21 of the LED 25. .

These drive line connections with conductive barrier material 240 (and / or composite properties of drive lines 140 and 240) serve to reduce the voltage drop along lines 140 and 240 when extending across the array. do. As a result, the display can be made very large, for example, at least 1 meter wide (ie 30 inches) wide. Before the present invention appears, it is difficult (probably even impossible) to make an active-matrix electroluminescent display very large due to the voltage error along the drive line when conducting current in the conduction luminous state. However, the present invention can also be used as an advantage in smaller displays to improve image quality.

Thus, along lines 140 and 240, the conductive barrier material 240 is at least twice as large (possibly even in size) in cross-sectional area than the conductor layer providing the electrode connections 4, 140 to the drive element T1. Has In general, conductive barrier material 240 may have a thickness Z in the circuit board 100 that is a factor of two or more (eg, at least five times) than the thickness z of such conductor layer 140. In certain instances, Z may be between 2 μm and 5 μm compared to 0.5 μm or less for z. In general, conductive barrier material 240 may have a line width Y that is the same width (or even at least twice) the line width y of conductor layer 140. In a particular example, Y may be 20 μm compared to 10 μm for y.                 

It is important to note the other features present in this device structure in order to reduce the effects of voltage fluctuations on the supply lines 230, 140, 240. Thus, smoothing capacitor Cs is formed between drive lines 140 and 240 (including conductive barrier material 240) and additional supply line 230 (associated with upper electrode 23 of LED 25). do. As shown in FIG. 1, the sides and top of the conductive barrier material 240 are coated with an insulating layer 40. The thickness and dielectric properties of this insulating coating 40 may be selected to form the capacitor dielectric of the smoothing capacitor Cs. Another plate of capacitor Cs is formed by supply line 230 (including and / or connecting LED top electrode 23), which is above the top of conductive barrier material 240. Extends over the insulating coating 40. In general, this insulating coating 40 may be made of silicon dioxide or silicon nitride or aluminum oxide and has a thickness of 10 nm (nanometer) to 0.5 μm (micrometer).

Layout Embodiment of FIG. 2

In the particular layout example of FIG. 2, the extension of the TFT electrode 4 of the pixel row forms a continuous line 140 for that row. This line 140 extends parallel to the barriers 210 (240, 40). This barrier 210 (shown in phantom in FIG. 2) extends parallel to the address (row) conductor 150 of the substrate 100.

As shown in FIG. 2, when the barriers 210, 240, 40 extend parallel to one or more lines (such as lines 140 and 150 in FIG. 2), these lines are defined by the barrier 120. Can overlap completely. Moreover, the width Y of the barriers 210 (240, 40) of FIG. 2 is so large that both lines 140 and 150 overlap. Nevertheless, the thin film pixel circuit of FIG. 3 will slightly interfere with the pixel region as shown by hatched circuit region 120.

The conductive barrier material 240 is connected to the node of the drive element T1 and one plate of the holding capacitor Ch in the via 12b. 2 illustrates an embodiment where each pixel 200 has a respective via 12b between the electrode connection 140, 4 for each drive element T1 of the pixel and the conductive barrier material 240.

1 and 2, at least a majority of the drive element T1 is located below the conductive barrier material 240. The width Y and the length of the conductive barrier material 240 allow for at least a majority of the sustain capacitor Ch to be located below the conductive barrier material 240, for example in FIGS. 2 and 4. The drive element T1 of each pixel may have each electrode 4 located in the via 12b and / or each capacitor plate 155 may be located in the via 12b.

Each barrier 210, 240, 40 in the FIG. 2 layout may extend across the entire array. Thus, it is possible to form a continuous supply line of conductive barrier material 240 that is connected to the electrode connections 4, 140 for each drive element T1 of each pixel 200. In this case, it may be parallel to line 140. However, if the line resistance of the conductive barrier material 240 is sufficiently low, the substrate conductor line 140 may simply be replaced. Thus, the extension 140 of the TFT electrode 4 does not need to form a continuous line, and an increase in the pixel aperture can be achieved by omitting the length of the line 140 in most pixel regions.

Layout Embodiment of FIG. 5

The special layout example of FIG. 5 is a variation of FIG. 2. In this variation, the barriers 210, 240, 40 extend in the row and column direction of the array. Thus, in this particular embodiment, the barriers 210, 240, 40 are interconnected between the pixels to form a network of conductive barrier material 240 in the row and column directions.

Compared to separate parallel lines, there are several potential advantages when employing a network of conductive barrier materials 240. Thus, the network of conductive barrier material 240 is effectively an aperture forming sheet conductor, where the resistance between any two points is lower than in the FIG. 2 layout. This may also provide a design option to the LED 25 when determining the capacitance value of the smoothing capacitor Cs for the power supply.

Layout Embodiment of FIGS. 6 and 7

Reduction of the voltage drop along the addressing (row) line 150 is also desirable in large arrays. 6 and 7 illustrate how an additional barrier 210c of the same configuration as the barrier 210 (ie, consisting predominantly of conductor barrier material 240) can be used for this. The specific layout example of FIGS. 6 and 7 is provided as a variant of FIG. 2. In each case, the pixel barrier 210, which provides at least the low resistance 240 of the drive lines 140, 240, is also retained in the device.

An additional barrier 210c of conductive material 240 extends parallel to the row conductor 150 as shown in FIGS. 6 and 7. The barrier is connected to the row conductor 150 in the circuit board 100 at an additional via 12c in the intermediate insulation layer 12 to reduce the voltage drop along the row conductor 150. As such, this additional barrier 210c backs up a portion of the row line 150 to reduce its resistance. The additional barrier is insulated from the barrier 210 forming at least a portion of the drive lines 140, 240.

In the variant of FIG. 6, an additional barrier 210c backing up the row line 150 extends parallel to the barrier 210 providing at least the low resistance 240 of the drive lines 140, 240. Thus, these barriers 210 and 210c extend in the same direction between the pixels 200 of the array.

In the variant of FIG. 7, the barrier 210 extends parallel to the thermal conductor 160. The barrier provides a continuous low resistance drive line 240 that replaces line 140 as in FIG. 8. Such a modification can be made to the display device of FIGS. 1-4 without including an additional barrier 210c to the row line 150. However, FIG. 7 shows a layout that includes an additional barrier 210c to back up the row line 150. In this embodiment, the additional barrier 210c extends across the barrier 210 of the drive lines 140, 240. Thus, the barrier 210 extends in one direction of the array and the barrier 210c extends in the transverse direction. Barriers 120 and 120c thus form a network between the pixels of the array. However, unlike FIG. 5, the conductive barrier material 240 in the transverse direction of the network (barrier 210c) is insulated from the conductive barrier (barrier 210) in the other direction.

Circuit embodiment of FIG. 8

As described above in connection with FIG. 2, the extension 140 of the TFT electrode 4 is a continuous line when the barriers 210, 240, 40 themselves provide a continuous line of conductive barrier material 240. There is no need to form. Thus, continuous lines of conductive barrier material 240 may replace lines 140 of circuit board 100. Such a scenario is shown in the circuit diagram of FIG. 8. A continuous line of conductive barrier material 240 is connected to the electrode connection 140 to each drive element T1 and sustain capacitor Ch of every pixel 200 in the row. Each pixel 200 is provided with a respective via 12b between the electrode connection 140 and the conductive barrier material 240.

Circuit Embodiment of FIG. 9

In the embodiment described so far with reference to FIGS. 1-8, line 230 is grounded to form a return line, while voltage Vdd is applied to lines 140 and 240 as a power supply line. 9 illustrates an alternative configuration where lines 140 and 240 (including conductive barrier material 240) are grounded to form a return line. In this case, the drive voltage Vdd is applied to the line 230 (including or connected to the upper electrode 23 of the LED 25). Thus, line 230 is now a power supply line.

Moreover, the upper electrode 23 of the LED 25 is now made of anode material, while the lower electrode 23 is formed of cathode material. Such a display, for example, emits light 250 through the top surface rather than through the substrate 100. The light emitting layer 22 may be made of a molecular (small molecule) organic semiconductor material, for example, or may be made of a semiconductor polymer.

However, as in the previous embodiment, the conductive barrier material 240 forms part of the drive line, that is, part of the line through which the LEDs 25 are connected through the drive element T1.

10 to 12 process embodiment

Apart from the configuration of the drive lines 140, 240, the active-matrix electroluminescent display device according to the invention can be constructed using known device and circuit techniques, for example as in the cited background references.

10-12 illustrate new process steps in certain manufacturing embodiments. The thin film circuit board 100 having the upper planar insulating layer 12 (for example made of silicon nitride) is manufactured in a known manner. Contact windows (such as vias 12a, 12b, 12c, etc.) are opened in layer 12 in a known manner, for example by photolithographic masking and etching. However, for manufacturing the device according to the invention, the pattern of these vias comprises vias 12b exposing the electrode connections 140, 4 of each drive element T1 for at least a portion of the pixel 200. . The resulting structure is shown in FIG.

Thereafter, an electrically-conductive material for barrier 210 is deposited on insulating layer 12 at least in vias 12a, 12b, 12c, and the like. The desired layout for the barrier 210 (such as in FIG. 2, 5, 6, or 7) is obtained using known masking techniques. FIG. 11 illustrates an embodiment in which at least bulk 240b of a conductive barrier material (eg copper or nickel or silver) is deposited by plating. In this case, a thin seed layer 240a, for example made of copper or nickel or silver, is first deposited over the insulating layer 12 and vias 12a, 12b, 12c, etc., and the barrier layout pattern is a photolithographic mask. The bulk 240b of conductive barrier material is then plated to the desired thickness Z. The resulting structure is shown in FIG.

Then, using CVD (chemical vapor deposition), an insulating material (eg silicon dioxide or silicon nitride) is deposited on the insulating coating 40. The deposited material remains on the sides and top of the conductive barrier material by patterning using known photolithographic masking and etching techniques. The resulting structure is shown in FIG.

After this, manufacturing continues in a known manner. Thus, for example, the conjugate polymer material may be inkjet printed or spin-coated with respect to the pixel 200. Barriers 240 and 40 with an insulating coating 40 can be used in a known manner, thereby preventing polymer overflow from the pixel region in the physical barriers 240 and 40. After this, the upper electrode materials 23, 230 may be deposited.

Modified process embodiment of FIG. 13

This embodiment uses an anodization (instead of deposition) process to provide an insulating coating 40 on at least the side of the barrier 210 adjacent the pixel region. In general, conductive barrier material 240 may comprise aluminum. The desired layout pattern of the deposited aluminum (eg, as in FIG. 2, 5, 6, or 7) can be defined using known photolithographic masking and etching techniques. 13 shows a photolithographically defined etchant-mask 44 held on top of aluminum barrier pattern 240.

Anodic insulating coatings of aluminum oxide are then formed on at least the sides of the aluminum barrier material 240 using known anodic oxidation techniques. Thus, no extra mask is needed to define the layout for this coating 40.

If the mask 44 is removed prior to this anodization, an anode coating is formed on both the side and top of the aluminum barrier pattern 240. However, FIG. 13 shows an example in which the mask 44 is maintained during this anodic oxidation so that the anode coating is formed only on the side of the aluminum barrier pattern 240. In a device having a supply line 230 extending above the tops of the barriers 210, 240, 40, an insulating polymer, or a mask 44 of, for example, silicon dioxide or silicon nitride, may be retained in the manufactured device. have.

Alternative conductive barrier embodiment of FIG. 14

In the embodiments described so far, the barrier 210 is shown primarily consisting of a conductive material 240. 14 shows a modified embodiment in which the barrier 210 consists primarily of an insulating material 244. In this case, the via 244b is etched or milled through the insulating material 244 to the electrode regions 140 and 4 of the TFT T1 in the circuit board 100. Metal coating 240 provides a conductive barrier material that extends over top of insulating barrier 210 and via 244b therethrough. This metal coating 240 backs up or replaces the thin film drive supply line 140.

Circuit board 100 may be formed with planar layer 12 and vias 12a and 12b as described above with reference to FIG. 10. Insulating bulk material 244 of FIG. 14 is formed thereon with vias 244b. The metal coating 240 of this barrier 210 may then be formed simultaneously with the main portion of the upper electrode 23 of the LED 25 in a self-aligned manner. Thus, a metal layer may be deposited simultaneously on the metal coating 240 and the electrode 23 separated by the shadow-masking effect of the protruding shape on the side of the barrier 210 as shown in FIG. 14.

Multiple Conductor Barrier Embodiment of FIG. 15

FIG. 15 shows a composite of two side-by-side barriers 210 and 210x, each comprising a metal core 240, 240x insulated with each coating 40, 40x. These side by side multiple conductor barrier structures 210, 210x can be designed and used in a variety of ways.

In one form, for example, the metal cores 240 and 240x form parallel drive and addressing lines 140 and 150, for example, as cross-sections of the parallel barrier lines 140 and 150 of FIG. 6, respectively. Backup).

In another form, for example, one of the barriers 210x may be separated into insulated portions that provide additional components, for example the capacitor described below with reference to FIG. 17.

Multiple Conductor Barrier Embodiments of FIGS. 16 and 17

The embodiment of FIG. 16 is similar to FIG. 7 in that it has an insulated barrier length 210c extending laterally to the drive line barriers 210 and 140. This transverse barrier 210c may back up line 150 as previously described with reference to FIG. 7. However, the transverse barrier can be constructed and used for other purposes.

Thus, for example, the transverse barrier 210c may itself have a multiple conductor structure as shown in FIG. 17. This barrier embodiment includes a metal core 240c as the primary conductive barrier material that is connected to a circuit element such as 4 or 5, etc. on the substrate 100 and has an insulating coating 40c thereon. However, the embodiment of FIG. 17 additionally includes a metal coating 240d that is present on insulating coating 40c over the top and sides of core 240c. This metal coating 240d is connected to other circuit elements of the substrate 100, such as, for example, elements 6, 5, 4, and the like.

This barrier structure of FIG. 17 is more flexible than described above. The barrier structure allows the metal core 240c and the metal coating 240d to be used for other purposes to reduce its line resistance for other purposes, for example by backing up or even replacing different lines 140, 150 or 160. do. The metal coating 240d may serve as a coaxial shield for the signal on the core line 240c. Alternatively, metal coating 240d may be placed at a specific location along barrier 210c where a particular connection or component is required, for example, in an individual pixel or sub-pixel.

Instead of shielding, these multiple conductor structures 240c and 240d for barrier 210c may have two lines, for example backup or replacement barrier line 140 (including core 240c) and backup or replacement barrier line 150. ) (Including coating 240d). In this case, however, the thickness and dielectric properties of insulating coating 40c need to be selected to reduce the parasitic capacitance and coupling between these lines 140 and 150.

Of particular interest is an embodiment in which the multiple conductor structures 240c and 240d of FIG. 17 are designed to form a capacitor having a capacitor dielectric 40c. Thus, the separated and / or insulated lengths of the metal core 240c, the insulating coating 40c, and the metal coating 240d will together form a capacitor connected between the substrate circuit elements 4, 5, and the like.

Such a capacitor is, for example, between the supply line 140 (the main electrode line 4 of the TFT (T1)} and the gate line 5 of the TFT T2 (the main electrode line 3 of the TFT (T1)}. It will be designed to provide a separate holding capacitor Ch for each of the connected pixels 200. 16 shows a suitable pixel layout with such sustain capacitor barriers 210c and Ch.

The capacitor structures 240c, 40c, 240d of FIG. 17 even have lines 230 and 240 to form smoothing capacitors instead of or in addition to those provided by, for example, the structures 240, 40, 230 in FIG. 1. Can be connected between.

In the embodiments described so far, the conductive barrier material 240 is a thick opaque metal, such as aluminum, copper, nickel or silver. However, other conductive materials 240 may be used, for example metal silicides or (less advantageously) degenerately-doped polysilicon, all of which are surface-oxidized to provide an insulating coating. 40 is formed. If transparent barrier 210 is required, ITO can be used for conductive barrier material 240.

By reading this disclosure, other variations and modifications will be apparent to those skilled in the art. Such modifications and variations will include equivalents and other features that are already known in the art (e.g., the referenced background references) and that can be used in place of or in addition to the features already described herein.

Although the claims are formulated in the specific combination of features in this application, whether the scope of the disclosure is to the same invention as is currently claimed in any claim, and the same technical problems as the present invention solved It is to be understood that it also includes any new feature or any new combination of features, whether expressly or implicitly disclosed herein, or a generalization thereof, whether or not mitigating some or all.

Applicant hereby recognizes that new claims may be formed in such features and / or combinations of such features while executing the present application or any further application derived therefrom.

As mentioned above, the present invention relates to an active-matrix electroluminescent display device, in particular using, but not limited to, light emitting diodes made of semiconductor conjugated polymers or other organic semiconductor materials. The present invention is also used for manufacturing such devices and the like.

Claims (25)

An active-matrix electroluminescent display device comprising a circuit board, wherein an array of pixels is provided on the substrate, and there is a physical barrier between neighboring pixels in at least one direction of the array, each pixel being in series on the circuit board. A current-driven electroluminescent element connected to a supply line by a drive element, the physical barrier being partially made of an electrically-conductive material insulated from the electroluminescent element and providing at least a portion of the supply line, And the conductive barrier material is connected to each drive element of the pixel through a contact window in an intermediate insulating layer between the barrier and the drive element. The insulating coating of claim 1, wherein the insulating coating extends on the side and top of the conductive barrier material, and a further supply line includes the top electrode of the electroluminescent element, and extends over the layer of the insulating coating on the conductive barrier material. Active-matrix electroluminescent display device. 3. The insulating coating of claim 2 wherein the insulating coating forms a capacitor dielectric of a smoothing capacitor between the drive supply line comprising the conductive barrier material and a further supply line including an upper electrode of the electroluminescent element. Active-matrix electroluminescent display device. 4. An active-matrix electroluminescent display device according to any one of the preceding claims, wherein each pixel has a respective contact window between the conductive barrier material and an electrode connection to each drive element of the pixel. 4. An active-matrix electroluminescent display device according to any one of the preceding claims, wherein the drive element of each pixel has a respective electrode located in the contact window connected to the conductive barrier material. 5. The active-matrix electroluminescent display device of claim 4, wherein a majority of the drive elements are located below the conductive barrier material. 4. The method of any one of claims 1 to 3, wherein each pixel comprises a retaining capacitor to hold the drive element in a given conducting state, wherein the conductive barrier material is a node of the drive element and the hold in the contact window. An active-matrix electroluminescent display device connected to one plate of a capacitor. 8. The active-matrix electroluminescent display device of claim 7, wherein a majority of the sustain capacitor is located below the conductive barrier material. 8. The active-matrix electroluminescent display of claim 7, wherein the holding capacitor is formed by each insulated length of the additional barrier extending across the supply line barrier and including a metal coating on the dielectric coating on the metal core. device. 5. The active-matrix electroluminescent display device of claim 4, wherein along the drive supply line, the conductive barrier material has a cross-sectional area that is two times larger and less than 20 times greater than the conductor layer providing the electrode connection to the drive element. 5. The active-matrix electroluminescent display device of claim 4, wherein along the drive supply line, the conductive barrier material has a thickness that is two times larger and less than ten times greater than the conductor layer providing the electrode connection to the drive element. . 4. An active-matrix electroluminescent display device according to any one of the preceding claims, wherein the physical barrier is made of the conductive barrier material (including metal). The active barrier of claim 1, wherein the physical barrier extends across the entire array as a continuous supply line of the conductive barrier material connected to an electrode connection to each drive element of each pixel. Matrix electroluminescent display device. 4. An active-matrix electroluminescent display device according to any one of the preceding claims, wherein the physical barrier between pixels extends as a network of conductive barrier materials in the row and column direction of the array. 4. The active-matrix electroluminescent display device according to claim 1, wherein the electroluminescent element is in an additional window in the intermediate insulating layer and has a bottom electrode connection with the drive element. 4. The transistor of claim 1, wherein the driving element is a thin film transistor having a source and a drain electrode connecting a main current path of the thin film transistor between the conductive barrier material and a lower electrode of the electroluminescent element. Active-matrix electroluminescent display device. 4. A drive according to any one of the preceding claims, wherein the driving element of the pixel is connected to a row and column conductor of the circuit board extending across the array for addressing each pixel and comprising the barrier. And a supply line extending parallel to said row or column conductor. 4. The drive element according to any one of claims 1 to 3, wherein the driving element of the pixel is connected to the row and column conductors of the circuit board extending across the array for addressing each pixel and adding conductive material. A barrier extends parallel to the row conductor and is insulated from the barrier forming at least a portion of the drive supply line and a contact window in the intermediate insulation layer on the circuit board to reduce voltage drop along the row conductor. An active-matrix electroluminescent display device coupled to the row conductor. 4. An active-matrix electroluminescent display device according to any one of the preceding claims, wherein each electroluminescent element comprises a light emitting diode of an organic semiconductor material between an upper electrode and a lower electrode. A method of manufacturing an active-matrix electroluminescent display device according to any one of claims 1 to 3, wherein (a) opening a contact window in an intermediate insulating layer on the circuit board to expose electrode connections for each drive element of the pixel; (b) forming a physical barrier on the circuit board having insulation at the side of the physical barrier adjacent the pixel region; (c) providing the electroluminescent element in the pixel region between the physical barriers, And the conductive barrier material is provided by depositing an electrically-conductive material for connection in the contact window of the intermediate insulating layer. 21. The active-matrix of claim 20, wherein step (b) comprises forming the physical barrier as a core of the electrically-conductive material and depositing an insulating coating on the side of the conductive barrier material. Method of manufacturing an electroluminescent display device. 22. The method of claim 21, wherein the bulk of the core of the conductive barrier material is deposited by plating. 23. The method of claim 21, wherein the conductive barrier material comprises aluminum and the insulating coating is formed on the side of the aluminum barrier material by anodization. 21. The method of claim 20, wherein step (b) includes forming a physical barrier made of an insulating material, wherein vias extend through the physical barrier for connection with circuit elements in a contact window of the intermediate insulating layer. Wherein the electrically-conductive material is deposited as a conductive coating on top of the physical barrier and vias passing through the physical barrier. 25. An active-matrix electroluminescent display device according to claim 24, wherein the conductive coating on the physical barrier and the top electrode of the electroluminescent element are deposited simultaneously and separated by the shadow-masking effect of the protrusion on the side of the physical barrier. Manufacturing method.

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