JP4909677B2 - Display device - Google Patents

Description

  The present invention relates to a display device, and more particularly to a passive matrix display device in which pixels are formed at each intersection of a plurality of scanning electrodes extending in a row direction and a plurality of signal electrodes extending in a column direction.

  An organic LED (Light-Emitting Diode) element is also referred to as an organic EL (Electro Luminescence) element, and is an element utilizing a phenomenon in which light is emitted by excitons generated by recombination of electrons and holes injected into an organic substance. It is.

  In recent years, display devices using this organic LED element have been actively developed. This is because the organic LED display device has a wider viewing angle, faster response speed, higher contrast, and the like than the liquid crystal display device.

  One of the driving methods of the organic LED display device is a passive driving method that is duty driving (see, for example, Patent Document 1). In this method, a switching element such as a TFT is not provided in a pixel portion, and a target image is displayed by passive driving using an electrode layer.

  FIG. 5 shows a conventional organic LED display device by passive driving.

  In FIG. 5, the organic LED display device 21 has a structure in which an anode 23, an organic layer 24, and a cathode 25 are sequentially laminated on a glass substrate 22. Here, the anode 23 and the cathode 25 are arranged such that the intersecting portions thereof are arranged in a matrix. When a voltage is applied to the anode 23 and the cathode 25, holes are injected from the anode 23 and electrons are injected from the cathode 25 as carriers. When these carriers recombine inside the organic layer 24, excitons are generated to emit light.

  In the organic LED display device 21, for example, when the cathode 25 is a scanning electrode and the anode 23 is a signal electrode, the cathode 25 is driven by a common wiring, and the anode 23 is driven by a segment wiring. When the drive current corresponding to the image data is supplied to the segment wiring while the common wiring is sequentially set to the scanning potential, the organic layer 24 at each intersection of the anode 23 and the cathode 25 has a light emission amount corresponding to the image data. Emits light.

Japanese Patent Laid-Open No. 05-053509

  By the way, in the liquid crystal display device, an image is displayed by progressive driving that scans the common wiring in order from the end of the display area. In this case, the frame frequency is about 60 Hz. However, when this is performed on a passive matrix organic LED display device, there is a problem that a flicker phenomenon occurs. This is because the organic LED display device has a faster response speed than the liquid crystal display device.

  In an organic LED display device, it is effective to increase the frame frequency to 80 Hz to 100 Hz in order to suppress the flicker phenomenon. However, although this method can reduce the flicker phenomenon, it causes a problem that power consumption increases.

  On the other hand, in a display device using a cathode ray tube, an image is displayed by an interlace method in order to reduce the flicker phenomenon. In the interlace method, for example, the odd-numbered common lines are sequentially driven from the top of the display area, and then the even-numbered common lines are sequentially driven from the top.

  Therefore, in an organic LED display device, it is conceivable to perform interlaced driving instead of progressive driving. FIG. 6A shows an odd-numbered frame created by driving odd-numbered common lines in a conventional organic LED display device. FIG. 6B shows an even frame created by driving even-numbered common lines. One screen is composed of odd frames and even frames. In these figures, the shaded area represents a pixel to be lit.

  However, even with interlaced driving, when the frame frequency is 60 Hz, a flicker phenomenon occurs, and the problem cannot be solved.

  The present invention has been made in view of such problems. That is, an object of the present invention is to provide an organic LED display device capable of suppressing the flicker phenomenon without increasing power consumption.

  Other objects and advantages of the present invention will become apparent from the following description.

The present invention relates to a passive matrix display device in which pixels are formed at each intersection of a plurality of scanning electrodes extending in a row direction and a plurality of signal electrodes extending in a column direction.
The scanning electrode has an electrode portion protruding in a column direction at a portion intersecting with the signal electrode, and a protruding direction of the electrode portion provided in a portion intersecting with the signal electrode in an odd number column and an even number column And the protruding direction of the electrode portion provided at the portion intersecting with the signal electrode is opposite to each other,
The scanning electrodes are interlaced scanned.

  In the present invention, a signal for driving the signal electrodes in the even-numbered columns corresponding to the pixel data of the odd-numbered rows among the pixel data of the progressive method constituted by the frames composed of the odd-numbered rows of pixels and the even-numbered rows of pixels; A signal for driving the signal electrodes in the odd columns corresponding to the pixel data in the even rows is combined with a signal for driving the scan electrodes in the odd rows, thereby creating a first sub-frame, and pixels in the odd rows A signal for driving the signal electrodes of the odd columns corresponding to the data and a signal for driving the signal electrodes of the even columns corresponding to the pixel data of the even rows, and then storing the stored signals in the even rows A second subframe can be created by combining with a signal for driving the scan electrode.

  In the present invention, it is preferable that an auxiliary electrode is provided in a portion extending in the row direction of the scanning electrode. In this case, the auxiliary electrode can be made of a material having a resistance lower than that of the material constituting the scanning electrode. The auxiliary electrode may be made of the same material as the scanning electrode.

  In the present invention, the display device may be an organic LED display device.

  The display device of the present invention has an electrode portion protruding in the column direction at the portion where the scan electrode intersects with the signal electrode, and the protruding direction of the electrode portion provided at the portion intersecting with the odd-numbered signal electrode, The scanning electrodes are interlaced-scanned in directions opposite to the protruding directions of the electrode portions provided at the portions intersecting with the even-numbered signal electrodes. Thereby, it is possible to suppress the flicker phenomenon without increasing the power consumption.

  FIG. 1 is a schematic plan view of an organic LED display device according to the present embodiment. In this organic LED display device, organic LED elements (not shown) are provided at intersections of a plurality of cathodes 1 extending in the row direction and a plurality of anodes 2 extending in the column direction to form pixels.

  When the cathode 1 is a scanning electrode and the anode 2 is a signal electrode, the cathode 1 is driven by common wiring and the anode 2 is driven by segment wiring. An image can be displayed by appropriately supplying a drive current to the segment wiring while sequentially setting the common wiring to the scanning potential.

  In the organic LED display device according to the present embodiment, the anode 2 extends linearly in the column direction. On the other hand, the cathode 1 extends linearly in the row direction across the anode 2, but an electrode portion 3 protruding in the column direction is provided at a portion where the cathode 1 intersects the anode 2. Here, the protruding direction of the electrode portion 3 provided in the portion intersecting with the odd-numbered rows of anodes 2 and the protruding direction of the electrode portion 3 provided in the portion intersecting with the even-numbered rows of anodes 2 are opposite to each other. . That is, the electrode portions 3 are arranged in a staggered manner in plan view. In such an organic LED display device, when the cathode 1 is interlaced scanned, the frame rate can be artificially doubled, so that the flicker phenomenon can be suppressed.

  FIG. 2A schematically shows a first subframe created by driving odd-numbered common lines in the organic LED display device according to the present embodiment. FIG. 2B schematically shows a second subframe created by driving even-numbered common lines. In these figures, the shaded area represents a pixel to be lit.

  As described in FIGS. 6A and 6B, when interlace scanning is performed with a conventional organic LED display device, each frame constituting one image is composed of pixels arranged in stripes. . On the other hand, in the present embodiment, as shown in FIGS. 2A and 2B, pixels constituting each frame are arranged in a staggered manner.

  FIG. 3 shows a part of the data processing in the case of performing the display of FIG. 2 (a) or (b). In this example, progressive pixel data composed of a frame made up of pixels of odd rows and pixels of even rows is processed, first, the common wiring corresponding to the cathode 1 of odd rows is driven, and then The common wiring corresponding to the cathode 1 is driven. That is, the cathode 1 is interlaced scanned based on progressive pixel data. Note that processing based on interlaced pixel data may be used instead of progressive pixel data.

  The image data processing shown in FIG. 3 will be described in detail below.

  In the example of FIG. 3, the signal for driving the anodes of the even columns corresponding to the pixel data of the odd rows among the pixel data of the progressive method configured by the frame including the pixels of the odd rows and the pixels of the even rows, A signal for driving the anodes in the odd columns corresponding to the pixel data in the rows is combined with a signal for driving the cathodes in the odd rows, thereby creating a first subframe and an odd number corresponding to the pixel data in the odd rows By storing a signal driving the anode of the column and a signal driving the anode of the even column corresponding to the pixel data of the even row, and then combining this stored signal with a signal driving the cathode of the even row, A second subframe is created. Here, the signal for driving the anode corresponds to the data of the segment wiring. The signal for driving the cathode corresponds to the data of the common wiring. Thus, after driving the odd-numbered common wirings, the even-numbered common wirings are driven to interlace scan the cathode 1.

  In FIG. 1, the pixel data in the first row from the top is divided into odd-numbered segment wiring data and even-numbered segment wiring data. Here, in order to perform the display of FIG. 2A, the data of the even-numbered segment wiring is used. On the other hand, the segment wiring data of the odd columns is stored in the RAM. Then, the image data of the first row is created by combining the data of the even-numbered segment wiring and the data of the first common wiring from the top.

  The pixel data in the second row from the top in FIG. 1 is also divided into odd-numbered segment wiring data and even-numbered segment wiring data. In order to perform the display shown in FIG. 2A, the segment wiring data in the odd-numbered column is used. On the other hand, the segment wiring data of the even columns is stored in the RAM. Then, the image data of the second row is created by combining the data of the odd-numbered segment wirings with the data of the third common wiring from the top.

  The pixel data in the third row from the top in FIG. 1 are also divided into odd-numbered segment wiring data and even-numbered segment wiring data. In order to perform the display shown in FIG. 2A, the segment wiring data in the even-numbered columns is used. On the other hand, the segment wiring data of the odd columns is stored in the RAM. Then, the third row of image data is created by combining the data of the even-numbered segment wirings with the data of the third common wiring from the top.

  The pixel data in the fourth and subsequent rows from the top in FIG. 1 can be created by continuing the same processing. In this way, the odd-numbered common wirings are sequentially driven to create the first subframe shown in FIG. 2A, and image data is output to the organic LED display device.

  Next, the common lines in the even rows from the top are sequentially driven. The image data for each row is created as follows.

  In FIG. 1, the image data in the first row from the top is created by combining the odd-numbered segment wiring data stored in the RAM and the second common wiring data from the top.

  The image data in the second row from the top in FIG. 1 is created by combining even-numbered segment wiring data stored in the RAM and second common wiring data from the top.

  The pixel data in the third row from the top of FIG. 1 is created by combining the odd-numbered segment wiring data stored in the RAM and the fourth common wiring data from the top.

  The image data on and after the fourth line from the top of FIG. 1 can be created by continuing the same processing. In this way, the common lines in the even rows are sequentially driven to create the second subframe shown in FIG. 2B, and image data is output to the organic LED display device.

  In the organic LED display device of the present embodiment, a timing controller is required to perform the data processing shown in FIG. That is, when the timing controller displays an interlace video signal that constitutes one frame by the first subframe and the second subframe, the timing controller transmits data of a predetermined segment wiring in the first subframe. In the held state, image display based on the data of the odd-numbered common wiring is performed. On the other hand, in the second subframe, image display based on the data of the common wiring in the even-numbered rows is performed using the data of the segment wiring held previously.

  As described above, in the example of FIG. 3, when driving odd-numbered common wirings, data of some segment wirings is stored, and is extracted and used when driving even-numbered common wirings. Therefore, this organic LED display device requires a storage device for holding segment wiring data. For example, in the case of a monochrome organic LED display device having 64 common wires and 128 segment wires, the capacity of the storage device is considered to be sufficient. And if it is a memory | storage device of this capacity | capacitance, it can be provided in the inside of the drive driver of an organic LED display device. Note that a RAM is preferably used as the storage device in terms of circuit scale, cost, versatility, and the like.

  FIG. 4 is a partial plan view of the organic LED display device according to the present embodiment. Although not shown in detail, the organic LED display device is formed around a support substrate, a plurality of organic LED elements formed on the support substrate, and a display unit in which the plurality of organic LED elements are arranged. And a counter substrate overlapped with the support substrate through the seal material. A color filter and a protective film may be provided on the support substrate, and an organic LED element may be formed on the protective film.

  As shown in FIG. 4, the organic LED display device 11 includes an anode 12, an organic layer 13, and a cathode 14 that are sequentially provided on a support substrate (not shown). Here, the cathode 14 is driven by the common wiring, and the anode 12 is driven by the segment wiring.

  As the support substrate, a material having a high transmittance for visible light is used. Specifically, in addition to inorganic glass such as alkali glass, alkali-free glass and quartz glass, polyester, polycarbonate, polyether, polysulfone, polyethersulfone, polyvinyl alcohol, and fluorine-containing polymers such as polyvinylidene fluoride and polyvinyl fluoride. Transparent materials such as

The anode 12 is made of a transparent metal having a high work function, an alloy thereof, or another conductive compound. For example, ITO (Indium Tin Oxide), SnO ₂ or ZnO can be used as the anode material. The anode 12 can be formed by, for example, a sputtering method or a vapor deposition method.

  The organic layer 13 may have a single-layer structure including only a light-emitting layer, or a laminated structure having a layer such as a hole injection layer, a hole transport layer, an electron injection layer, or an electron transport layer in addition to the light-emitting layer. It may be. For example, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode configuration, anode / light emitting layer / electron transport layer / cathode configuration, or anode / hole transport layer / light emission Examples include a layer / electron transport layer / cathode structure.

  For the cathode 14, a metal having a small work function or an alloy thereof is used. Specific examples include alkali metals, alkaline earth metals, and metals of Group 3 of the periodic table. Of these, aluminum (Al), magnesium (Mg), or alloys thereof are preferably used because they are inexpensive and have good chemical stability. The cathode 14 can be formed by, for example, a vapor deposition method.

  The anode 12 is linearly separated by the insulating film 15. For example, a polyimide film or the like is used as the insulating film 15.

  The cathode 14 has an electrode portion 16 protruding in the column direction at a portion intersecting with the anode 12. The protruding direction of the electrode portion 16 provided at the portion intersecting with the odd-numbered rows of anodes 12 and the protruding direction of the electrode portion 16 provided at the portion intersecting with the even-numbered rows of anodes 12 are opposite to each other. By forming the cathode 14 in such a shape, a subframe as shown in FIG. 2A or 2B can be created when the common wiring is interlaced.

  A partition wall 17 is provided around the cathode 14. The partition wall 17 is made of an insulating resin such as polyimide and has a function of separating the organic layer 13 and the cathode 14.

  When the shape of the cathode 14 is set as described above, the line width of the portion extending in the row direction becomes narrow, which causes an increase in the resistance value in this portion. Therefore, in the present embodiment, it is preferable to provide the auxiliary electrode 18 in a portion extending in the row direction of the cathode 14. The auxiliary electrode 18 is preferably made of a material having a lower resistance than the material forming the cathode 14, but may be formed using the same material as the cathode 14. In either case, the resistance value in the portion of the cathode 14 extending in the row direction can be reduced. In the former case, it is preferable to provide the cathode 14 after the auxiliary electrode 18 is formed. On the other hand, in the latter case, the cathode 14 may be formed either before or after the auxiliary electrode 18 is formed.

  As described above, in the present embodiment, the cathode has an electrode portion protruding in the column direction at the intersection with the anode, and the electrode portion provided at the portion intersecting with the anode in the odd-numbered column The protruding direction and the protruding direction of the electrode portions provided at the portions intersecting with the even-numbered rows of anodes are opposite to each other. In such an organic LED display device, when the cathode is interlaced, the frame rate can be artificially doubled. Therefore, it is possible to suppress the flicker phenomenon without increasing the frame frequency. That is, according to the present invention, it is possible to suppress the flicker phenomenon without increasing the power consumption, and further, it is expected to reduce the power consumption by lowering the frequency as compared with the prior art.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  In the said embodiment, although the organic LED display apparatus was mentioned as an example, this invention is not limited to this, It is also possible to apply to another display apparatus. For example, the present invention can be preferably applied to a liquid crystal display device having a high response speed.

It is a plane schematic diagram of the organic LED display device in this Embodiment. In the organic LED display device of the present embodiment, (a) is a schematic diagram of a first subframe, and (b) is a schematic diagram of a second subframe. It is a figure which shows a part of data processing in the organic LED display device of this Embodiment. It is a fragmentary top view of the organic LED display device in this Embodiment. It is the conventional organic LED display device by passive drive. In a conventional organic LED display device, (a) is a schematic diagram of odd frames, and (b) is a schematic diagram of even frames.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,14,25 Cathode 2,12,23 Anode 3 Electrode part 11,21 Organic LED display 13,24 Organic layer 15 Insulating film 16 Electrode part 17 Partition 18 Auxiliary electrode 22 Glass substrate

Claims (5)

In a passive matrix display device in which pixels are formed at each intersection of a plurality of scanning electrodes extending in the row direction and a plurality of signal electrodes extending in the column direction,
The scanning electrode has an electrode portion protruding in a column direction at a portion intersecting with the signal electrode, and a protruding direction of the electrode portion provided in a portion intersecting with the signal electrode in an odd number column and an even number column And the protruding direction of the electrode portion provided at the portion intersecting with the signal electrode is opposite to each other,
The scan electrodes are interlaced scanned ;
A signal for driving the signal electrodes in the even columns corresponding to the pixel data in the odd rows and the pixel data in the even rows in the progressive method pixel data constituted by the frames composed of the pixels in the odd rows and the pixels in the even rows. Is combined with a signal for driving the odd-numbered column of the signal electrode and a signal for driving the odd-numbered row of the scan electrodes, thereby creating a first subframe and an odd-numbered pixel data corresponding to the pixel data of the odd-numbered row A signal for driving the signal electrodes in the columns and a signal for driving the signal electrodes in the even columns corresponding to the pixel data in the even rows are stored, and then the stored signals are driven in the scan electrodes in the even rows. by combining the signals, a display device which is characterized that you create a second subframe. The display device according to claim 1, wherein an auxiliary electrode is provided in a portion extending in the row direction of the scan electrode . The display device according to claim 2 , wherein the auxiliary electrode is made of a material having a resistance lower than that of the material constituting the scanning electrode . The display device according to claim 2 , wherein the auxiliary electrode is made of the same material as the scanning electrode. The display device according to claim 1, wherein the display device is an organic LED display device.

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