JP3690643B2 - Passive matrix organic thin-film light-emitting display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a passive matrix organic thin film light emitting display using organic light emitting elements, and more particularly to a passive matrix organic thin film light emitting display that can be driven with low voltage, low power consumption, and high luminance.
[0002]
[Prior art]
Since organic light-emitting elements are self-luminous elements and have high visibility and can be driven at a low voltage, practical research has been actively conducted. The organic light-emitting device includes a transparent conductive film of an anode on a transparent substrate, a hole transport layer made of an organic material and a light-emitting layer, and a structure in which an organic layer having a metal film of a cathode is formed of two layers. A structure including three layers of a hole transport layer, a light emitting layer, and an electron transport layer is known.
[0003]
The light emission mechanism of the organic light emitting device is considered as follows. The electrons injected from the cathode and the holes injected from the anode recombine in the vicinity of the interface between the hole transport layer and the light-emitting layer to generate excitons. Unleash. This light is emitted to the outside through the transparent conductive film as the anode and the transparent substrate.
[0004]
One application of the organic light emitting device is a passive matrix type (simple matrix type) display as shown in FIG. 7 as an example. The passive matrix display shown in FIG. 7 includes anodes 1 arranged in a plurality of columns on a transparent substrate, cathodes 2 arranged in a plurality of rows so as to intersect the anodes 1, and sandwiched between them (a light emitting layer is formed). Including) organic layer. A display unit 3 is formed by forming one pixel with the light emitting portion in the intersecting region of the anode 1 and the cathode 2 as a unit and arranging a plurality of pixels two-dimensionally. The light emitting layers of R (red), G (green), and B (blue) are arranged in order as shown in FIG. By connecting the external drive circuit (the data side drive circuit 4 and the scan side drive circuit 5) and the display unit 3 via a connection unit formed by extending the anode 1 and the cathode 2 from the display unit 3 to the periphery of the substrate, a display is provided. The device is configured. As shown in FIG. 8, the image signal (RGB data) is temporarily stored in a frame memory 7 which is controlled to be written and read by the memory controller 6, and is read out in response to, for example, line sequential scanning. The gradation is controlled by 8 and supplied to the data side drive circuit 4. The memory controller 6, the gradation control circuit 8, the data side drive circuit 4, and the scan side drive circuit 5 have their operation timing controlled based on the clock from the clock generator 9, and display, for example, line-sequentially scanned images. Part 3 is displayed.
[0005]
[Problems to be solved by the invention]
In recent years, there has been a demand for larger displays and higher definition of displays. For this reason, in performing line sequential scanning, the time for selecting one scanning line is shortened. This means that in a passive matrix display, the time for emitting one scanning line is shortened, resulting in a decrease in luminance. In order to compensate for this, it is necessary to increase the voltage applied to the display unit, resulting in an increase in power consumption.
[0006]
In order to eliminate the limitation of the light emission time of the scanning line in the line sequential scanning, the active matrix driving is considered. This is characterized in that each pixel has a switching element and a capacitance for holding information. As a result, the driving duty can be made as close to 1 as possible, and high luminance can be obtained. However, on the other hand, a great deal of technology and cost are required to make the switching element, and the yield of the product is lowered.
[0007]
As described above, the passive matrix display has the problems that the luminance is reduced and the power consumption is increased when the definition is increased, and the active matrix display brings about a decrease in yield and an increase in cost.
[0008]
An object of the present invention is to realize low voltage driving, low power consumption, and high luminance by increasing the driving duty and increasing the light emission time in a passive matrix organic thin film light emitting display.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 has a first electrode portion arranged in a plurality of columns and a second electrode portion arranged in a plurality of rows on a transparent substrate, and In a passive matrix organic thin film light emitting display in which at least an organic light emitting layer is sandwiched between the first and second electrode portions , each column of the first electrode portions feeds a plurality of pixel electrodes and the plurality of pixel electrodes. A plurality of pixel electrodes arranged on the power supply electrode, the width of the power supply electrode is made smaller than the width of the pixel electrode, and a non-light emitting region between adjacent pixel electrodes on the same row Adjacent rows of feeding electrodes are arranged above, and the first and second electrode portions are divided into a plurality of sets of electrically independent matrices, respectively, and each matrix is driven simultaneously.
[0010]
According to a second aspect of the present invention, in the first aspect, the width of the non-light-emitting region is smaller than the width of the pixel electrode.
[0011]
According to a third aspect of the present invention, in the first or second aspect, the pixel electrode is a transparent conductive film, and the power supply electrode is a metal electrode.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of an electrode structure of a passive matrix organic thin-film light-emitting element according to the first embodiment of the present invention. In the present embodiment and each of the embodiments described below, the first electrode portion is an anode and the second electrode portion is a cathode. However, the present invention is not limited to this, and vice versa. .
[0014]
In the passive matrix organic thin-film light emitting device according to the first embodiment, an anode made of a transparent conductive film patterned in a stripe shape as a first electrode portion arranged in a plurality of rows on a substrate, A cathode made of a metal film as a second electrode portion that is arranged in a plurality of rows intersecting therewith is formed, and a display portion is formed by sequentially stacking an anode, an insulating film, an organic layer, and a cathode. The display unit 12 is formed by forming one pixel with the light emitting portion in the intersection region of the anode and the cathode as one unit, and arranging a plurality of the pixels two-dimensionally. The light emitting layers of R (red), G (green), and B (blue) are arranged in order as shown in FIG. Note that, of the portion where the anode and the cathode intersect, the insulating film is not formed in the portion that becomes the pixel, and the insulating film is formed in the portion that does not become the pixel. Thereby, it is possible to prevent a short circuit at the intersection of the anode and the cathode that do not become a pixel.
[0015]
The electrode 21 in the odd-numbered column of the first electrode part is connected to the odd-numbered column data side drive circuit 11, the electrode 22 in the even-numbered column of the first electrode part is connected to the even-numbered column data side drive circuit 10, The electrode part of the first electrode part is connected to the scanning side drive circuit 5 so that the odd-numbered column electrode 21 of the first electrode part and the odd-numbered electrode 23 of the second electrode part are electrically independent. By forming the matrix and the electrodes 22 in the even-numbered columns of the first electrode portion and the electrodes 24 in the even-numbered rows of the second electrode portion are separate electrically independent matrices, Line sequential scanning. That is, as shown in FIG. 9, the image signal (RGB data) is temporarily stored in the frame memory 7 which is controlled to be written and read by the memory controller 6, and read out in response to, for example, line sequential scanning. The gradation is controlled by the control circuit 8 and supplied to the odd-numbered column data side driving circuit 11 and the even-numbered column data side driving circuit 10. The operation timing of the memory controller 6, the gradation control circuit 8, the odd column data side drive circuit 11, the even column data side drive circuit 10 and the scanning side drive circuit 5 is controlled based on the clock from the clock generator 9. The For example, any one of the odd-numbered electrodes in the second electrode portion and any one of the even-numbered electrodes can be simultaneously selected to perform line sequential scanning. As a result, the driving duty can be doubled. That is, the time for configuring one screen can be shortened, and the selection time for each row can be lengthened. As a result, high definition can be achieved without lowering the frame frequency, and brightness can be improved in an organic thin film light emitting display having no memory effect. Therefore, low voltage driving and low power consumption are possible.
[0016]
FIG. 2 shows an example of an electrode structure of a passive matrix organic thin film light emitting device according to the second embodiment of the present invention.
[0017]
In this embodiment, the electrodes in each column of the first electrode portion are composed of (transparent) pixel electrodes (illustrated by 25) and power feeding electrodes (illustrated by 26) for feeding power to the pixel electrodes. The pixel electrodes on the same column are connected. The matrix configuration method, the drive circuit, the signal processing means in FIG. 9 and the like of the first embodiment are applied to this embodiment as they are.
[0018]
By narrowing the power supply electrode, the non-light-emitting portion is reduced, and each matrix is scanned line-sequentially simultaneously. By making the width of the power supply electrode 26 smaller (thinner) than the width of the pixel electrode 25, adjacent pixel electrodes can be brought close to each other on the same row. As a result, the non-light emitting portion is reduced and the pixel pitch is narrowed, thereby enabling high definition. In addition, wiring resistance can be reduced by using a metal electrode for the feed electrode which connects between pixels.
[0019]
FIG. 3 shows an example of an electrode structure of a passive matrix organic thin-film light emitting device according to the third embodiment of the present invention.
[0020]
In the present embodiment, the odd-numbered column data-side drive circuit 11 and the even-numbered column data-side drive circuit 10 are respectively arranged on the upper and lower sides of the display unit, and the two scanning-side drive circuits are configured to provide two scanning-side drives. Each of the circuits 5A and 5B is arranged on both sides of the display unit, and other than that is the same as the second embodiment, and the signal processing means having the same configuration as the signal processing means of FIG. 9 is applied. . When the pitch between the electrodes becomes narrow due to high definition, the circuit connection of the data side driving circuit is taken out by alternately taking out the feeding electrodes of each column of the first electrode portion in the opposite direction as in this embodiment. The convenience can be obtained. Furthermore, in this embodiment, power can be supplied from the two scanning-side drive circuits 5A and 5B on both sides to each electrode of the second electrode portion, so that the wiring resistance of each electrode of the second electrode portion is lowered and the voltage drop is reduced. Can be suppressed. As a result, the luminance difference in each electrode of the second electrode portion is reduced, which corresponds to an increase in area.
[0021]
FIG. 4 shows an example of an electrode structure of a passive matrix organic thin-film light emitting device according to the fourth embodiment of the present invention.
[0022]
The present embodiment is an example of an electrode structure when the arrangement of the power supply electrodes that connect the pixel electrodes is changed, and the electrodes in each row of the second electrode section are alternately connected to the two scanning side drive circuits 5A and 5B. The embodiment is the same as the embodiment of FIG. 3 except that the feeding electrode 26 is positioned at the end of the pixel electrode 25. The arrangement of the feeding electrodes that connect the pixel electrodes is not limited to these examples.
[0023]
FIG. 5 shows an example of an electrode structure of a passive matrix organic thin-film light emitting device according to the fifth embodiment of the present invention.
[0024]
In the present embodiment, the display unit 18 is divided into two parts, an upper part and a lower part, and each part has the same configuration as that of the second embodiment. Accordingly, four independent matrices are formed, and a driving duty four times that of a normal simple matrix can be obtained. In an organic thin film light emitting display, four times the luminance can be obtained.
[0025]
As shown in FIGS. 5 and 10, in the upper part, the odd-numbered column electrodes of the first electrode part are connected to the upper odd-numbered column data side drive circuit 17 and the even-numbered columns of the first electrode part are connected. The electrodes are connected to the upper even column data side drive circuit 16, the electrodes of the second electrode unit are connected to the upper scanning side drive circuit 13A, and the odd number column electrodes and the second electrode unit of the first electrode unit The odd-numbered electrode of the first electrode part is an electrically independent matrix, and the even-numbered electrode of the first electrode part and the even-numbered electrode of the second electrode part are electrically independent separately. The matrix is Similarly, in the lower part, the odd-numbered columns of the first electrode section are connected to the lower odd-numbered column data side drive circuit 14, and the even-numbered columns of the first electrode section are connected to the lower even number. The column data side drive circuit 15 is connected, the electrodes of the second electrode section are connected to the lower scanning side drive circuit 13B, and the odd-numbered columns of the first electrode section and the odd-numbered rows of the second electrode section The first electrode part is an electrically independent matrix, and the even-numbered column electrodes of the first electrode part and the even-numbered electrode lines of the second electrode part are electrically independent matrixes; To do. As a result, it is possible to perform line-sequential scanning simultaneously in the four matrices.
[0026]
FIG. 6 shows an example of an electrode structure of a passive matrix organic thin film light emitting device according to the sixth embodiment of the present invention.
[0027]
This embodiment has three data side drive circuits 27, 28, 29, and the power supply electrodes (illustrated by 26) of each column of the first electrode portion are sequentially connected to each data side drive circuit. Three electrically independent matrices can be constructed. The signal processing means of the three drive circuits can be configured in accordance with the circuit of FIG. 9 (the number of data side drive circuits is increased from two to three).
[0028]
In each of the above embodiments, in order to prevent the first electrode portion and the second electrode portion from contacting each other and causing a short circuit in the non-light-emitting region, the first electrode portion and the second electrode An insulating film is formed on the part. If the insulating film is a material having a mobility lower than that of the metal film, the carrier injecting property can be lowered and light emission loss can be reduced. For example, after forming a metal film, an oxide such as silicon oxide or alumina is formed by a sputtering method, a sol-gel method, or the like, and then formed into a desired shape by a method such as lift-off, or a photoresist, etc. It is applied to form an organic polymer film.
[0029]
In the present invention, the substrate can be applied to a film substrate such as a polymer film in addition to a glass substrate, and an organic film such as a color filter on the glass substrate.
[0030]
As the transparent conductive film material, in addition to ITO and indium zinc oxide, tin oxide, zinc oxide, aluminum tin oxide, and the like can be used.
[0031]
【The invention's effect】
As described above, according to the present invention, at least two rows can be simultaneously selected and line sequential scanning can be performed. As a result, a passive matrix organic thin film light emitting display capable of high definition, low drive voltage, low power consumption, and high brightness can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an electrode structure of a passive matrix organic light emitting device display according to the present invention.
FIG. 2 is a view showing another example of the electrode structure of the passive matrix organic light emitting device display according to the present invention.
FIG. 3 is a view showing still another example of the electrode structure of the passive matrix organic light emitting device display according to the present invention.
FIG. 4 is a view showing still another example of the electrode structure of the passive matrix organic light emitting device display according to the present invention.
FIG. 5 is a diagram showing an example of an electrode structure for four-screen division driving using the present invention.
FIG. 6 is a view showing still another example of the electrode structure of the passive matrix organic light emitting device display according to the present invention.
FIG. 7 is a diagram illustrating an example of an electrode structure of a conventional passive matrix organic light emitting device display.
8 is a block diagram of signal processing means applied to the drive circuit of FIG.
FIG. 9 is a block diagram of signal processing means applied to the drive circuit of FIG. 1 and the like.
10 is a block diagram of signal processing means applied to the drive circuit of FIG.
[Explanation of symbols]
5 Scanning side drive circuit 10 Even number column data side drive circuit 11 Odd number column data side drive circuit 12 Display unit 21 Odd column electrode 22 of first electrode unit Second column electrode 23 of first electrode unit Second Electrode 24 in odd-numbered row of electrode portion Electrode in even-numbered row in second electrode portion

Claims (3)

On the transparent substrate, it has first electrode portions arranged in a plurality of columns and second electrode portions arranged in a plurality of rows, and at least an organic light emitting layer is provided between the first and second electrode portions. In a passive matrix organic thin-film light-emitting display that is sandwiched,
Each column of the first electrode portion is composed of a feeding electrode for feeding power to the plurality of pixel electrodes and the plurality of pixel electrodes, arranging the plurality of pixel electrodes on the feeding electrode,
The width of the power supply electrode is made smaller than the width of the pixel electrode, and the power supply electrode in an adjacent row is disposed on a non-light emitting region between adjacent pixel electrodes on the same row,
The passive matrix organic thin-film light-emitting display, wherein the first and second electrode portions are divided into a plurality of sets of electrically independent matrices, and the matrices are driven simultaneously. The passive matrix organic thin film light emitting display according to claim 1,
A passive matrix organic thin film light emitting display, wherein a width of the non-light emitting region is smaller than a width of the pixel electrode.   3. The passive matrix organic thin film light emitting display according to claim 1, wherein the pixel electrode is a transparent conductive film, and the feeding electrode is a metal electrode.

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