TW200428334A - Current driving device and method of active-type OLED - Google Patents

Abstract

The invention discloses a current driving device and method of active-type OLED. The device comprises two adjacent sub-pixels odd-numbered sub-pixels and even-numbered sub-pixels). Each sub-pixel comprise a writing device, a switching device, a driving device, a control device, a storage device, a light-emitting device. The driving circuit comprises odd-numbered enable lines for odd-numbered sub-pixels; even-numbered enable lines for even-numbered sub-pixels; a data line commonly used by odd-numbered sub-pixels and even-numbered sub-pixels; a scanning line; a power source supplying line; and a common cathode line, so as to improve the non-uniform phenomenon of the OLED panel image, and save the number of data lines.

Description

200428334 V. Description of the invention (1) ~ [Technical field to which the invention belongs] The present invention relates to a current driving device and method for an active organic light emitting diode display, and particularly to an image for improving an active organic light emitting diode panel. Driving device and method for non-uniform data current writing (Current Programmed) of the present invention. [Prior art] Organic Light Emitting Display (0LED) can be divided into passive (Passive Matrix; PM0LED) and active according to the driving method. (Active Matrix; AM0LED). The so-called active driving OLED (AMOLED) uses a thin film transistor (TFT) and a capacitor storage signal to control the grayscale performance of the 0LED. Although the production cost and technical threshold of passive 0LEDs are low, the resolution cannot be improved due to the driving method. Therefore, the size of the application product is limited to about 5 inches, and the product will be limited to the low-resolution small-size market. In order to obtain high-definition and large images, active driving is the main method. The so-called active driving uses capacitors to store signals, so the pixels can still maintain the original brightness after the scanning line is scanned. As for passive driving, only The day element selected by the scan line will be lit. Therefore, in the active driving mode, 〇LED does not have to be driven to a very local bone level, so it can achieve better life performance, and it can also achieve high-resolution requirements. The technology of 0LED combined with TFT can actively drive 0LED, which can meet the requirements for the smoothness of the screen playback and the increasingly higher resolution in the current display market, fully displaying the above-mentioned superior characteristics of 0LED.

Page 5 200428334 V. Description of the invention (2) The technology for growing TFTs on glass substrates can be amorphous silicon (a-Si) process and low temperature polycrystalline silicon (L0w).

Temperature poly-silicon; LTPS) process. The biggest difference between LTPS TFT and a-Si TFT lies in the difference between its electrical properties and simplified process. LTPS TFT has a higher carrier mobility. Higher carrier mobility means TFT can provide more sufficient current, but its process is more complicated; a — Si TFT is the opposite. Although the carrier mobility of a-Si is not as good as LTPS, but because its process car is single and mature, it is It has a good competitive advantage in terms of cost. For example, due to the limitation of the low-temperature polycrystalline silicon (LTPS) process capability, the threshold voltage and electron mobility of the thin film transistor (TFT) device manufactured will be reduced. Variations' so the characteristics of each TFT element will be different. When the drive system uses an analog voltage modulation method to represent gray levels, because the characteristics of TFTs are different for different elements, so even if the same data voltage signal is input, the organic light emitting diode (0LED) will be different. The output current causes the brightness of the organic light-emitting diode (OLED) elements of different pixels on the display panel to be different. This phenomenon will cause the organic light-emitting diode panel to display an image with poor gray scales. The classification destroys the uniformity of the panel image (I in age Uniformity). Therefore, in order to solve the disadvantage of the uniformity of the panel image, the US patent US 6 , 229,506 "Active Matrix Light Emitting Diode Pixel Structure And Concomitant Method", this patent proposes a machine that uses data current programming (Current Programmed)

Page 6 200428334

System, to compensate for the TFT element ’s Mobility, Threshed V0Uage, and “shown in Figure 3”, to spread the variation of the strike to improve the uniformity of the image. Sound map. The schematic diagram of the diurnal circuit of US Patent 118 6,229,506. The operation principle of the mysterious circuit is described as follows: At the time of the description, the thunder # L solar body P1 and the transistor P3 are ON, and the transistor N1 is worn only. (OFF), μμ Pi ^ Μ., Gu Youlei said 栌 P1 at this time the data current on the data line 31 (the ^ ^ will flow through the transistor P1, and even μ times 4, 丨, this shell current ( Idata) is not equal to flowing through the transistor P2 / ;, L P2 will have a current (Ic) to charge the storage element Cs or i μ τ ′, and its current is equal to the data current (丨 ^) and the current flowing through the transistor P2 ( IP2) difference. The stored element. The charge or discharge action will increase or decrease the electric current, L (Ipz) flowing through the transistor P 2 and the storage element c $ charge or discharge action = continues until when When the magnitude of current flowing through transistor P2 is equal to the data current (Idata). When the magnitude of current flowing through transistor P2 (Ip2) is equal to When the material current (Idata) is reached, the voltage difference between the two ends of the storage element 03 is now providing transistor 1 " 2. The current (IP2) equals the data current (Idata) and the required Vsg (source and gate voltage difference) ). Then turn transistor P1 and transistor P3 off (OFF) to end the scan and enter the display phase. After entering the display phase, 'make transistor N1 conductive (0N) and switch the S terminal (source) of transistor P2 Extreme) connected to the power supply line (Supply Line) 33, because the voltage difference across the storage element C s can provide the transistor p 2 current (ιρ2) equal to the data current (Idata) V sg, so it flows through The current of the organic light-emitting diode (0LED) 34 will be equal to the current (ιρ2) or data current (Idata) flowing through the transistor P2, so that the organic light-emitting diodes 3 and 4 emit corresponding funds.

200428334 V. Description of the invention (4) Brightness of Idata. The driving structure of the above-mentioned active organic light emitting diode display of the daylight circuit technology is shown in FIG. 4. A frame (Frame) 40 (lFrame = 1/6 0 sec) starts from the first scanning line to perform the current writing operation (WHte) 40l of the current day frame 40 data, so that The voltage difference between the two ends of the storage element Cs can provide the current flowing in P2 (u equals the VS g required when the data / /, L (〖data). The first scan line 3 2 will complete the writing operation 401 and will rotate. The second scanning line 32 performs the current data writing operation 401 of the daylight frame 40, and at this time, the organic light emitting element 34 on the first scanning line 32 passes the same amount of current as the writing data. The current causes the organic light-emitting diode element 34 on the first scanning line 32 to display the current daytime brightness of the display 402. After the second scanning line 32 completes the writing operation 4 01, it will be rotated by the third Fortunately, the trace line 32 performs the writing operation of the data current of the current frame 40. At this time, the organic light-emitting diode element 34 on the second scanning line will pass the current equal to the data current to make the second The organic per-light diode element 34 on the scanning lines 32 displays 402 the current brightness of the screen.执行 Execute until the last scan line 32 completes the daytime frame 40 square meters ^ ^ ± A, and then repeat the first scan line 32. Once the surface frame 40 data current is written, the process is 401. However, the above-mentioned patent must Using P-Typ, the complexity of the process will relatively increase the content of the invention. E and N-Type C-TFT LTPS 'increasing the cost of manufacturing. The main purpose of the invention is to solve the above-mentioned traditional shortcomings.

200428334 V. Description of the invention (5) ----, to avoid the lack of existence, the present invention can realize the drive mode of data current writing A (Current Programmed) to compensate the threshold voltage (Threshold Voltage) and Electron mobility (,

Mobility) to improve the unevenness of the image of the active organic light emitting diode panel. At the same time, the number of data lines can be saved. You only need to know half the number of data lines in the design. If so, you can save manufacturing costs. In order to achieve the above purpose, the driving device proposed by the present invention is one or two adjacent sub-pixels (odd sub pixels and even sub pixels). Each sub pixel driving device includes 4 thin film transistors. (Thin Fiim

Transistor (TFT) and a capacitor (Capacitor); Also, each sub-book element includes a writing element, a switching element, a driving element, a control element, a storage element, a light emitting element, and the driving circuit includes Odd Line Enable for odd-numbered sub-pixels, Even Line Enable for even-numbered sub-pixels, a data line shared by odd-numbered sub-pixels and even-numbered sub-pixels, one The scanning line (scail Line), a power supply line (Supply Line), a total cathode line (common Une). [Embodiment] The detailed content and technical description of the present invention are described below in conjunction with the drawings: ○ Please refer to "shown in Figure 1", which is a schematic diagram of the device of the present invention. As shown in the figure: the driving device proposed by the present invention is one or two adjacent sub pixels (odd sub pixels 10 and even sub pixels 20), and each sub pixel driving device includes 4 thin-film electric elements. Crystal (Thin Film Transist ^ r; TFT) and a capacitor (Capacitor);

Page 9 200428334 V. Description of the invention (6) Each of the elements 20 includes a writing element τι and τι, a switching element T2 and T2, a driving element T3 and T3, a control element T4 and T4, and a storage Elements c and C, a light-emitting element 11 and 2 1; and the driving circuit includes an odd number of enable lines (Odd Line Enable) 101 and a power supply line (Supply line) 52 of an odd number of sub pixels 2 Even line enable 201 and a power supply line 52, a data line 50 shared by an odd sub-pixel 10 and an even sub-day 20, a scanning line

Line 51 'A common cathode line (common line 53). The source of the '4 writing element T1 / TΓ is connected to the data line 50; the gate of the switching element T2 / T2, (8 to 0 and the gate of the writing element T1 / T1' ( gate), its source is connected to the data line 50; the gate of the driving element T3 / T3 is connected to the above-mentioned writing element with a drain, and its source is connected to the above-mentioned power supply line 5 2/52, connected; the gate of the control element T4 / T4 'is connected to the above-mentioned scan line 51, and its source is connected to the odd-numbered enable line 101 (even-numbered enable line 201), and its drain The gate of the electrode changing element T2 / T2 'is connected to the gate; ”However, the storage element C / C has two ends, one end is connected to the source of the driving element T3 / T3, and the other end is connected to the driving element T3. / T3, the gate is connected to the drain connection of the writing element T2 / T2 '; the i / 21-end of the light-emitting element is positive, and is connected to the gate of the driving element T3 / T3, and One end is a negative electrode 'and is connected to the common cathode wire 53 above. The driving structure of the present invention is as shown in "Figure 2", which consists of a frame of 60 cycles (1Frame = 1/6 sec). During the period into two during a write once (Write peri〇d) 601, a display (Dispiay # 10200428334 p V. invention is described in (7) '~' ~ ^ -----

Per i od) 602. During the writing period 601, the common cathode line 53 is raised to a high potential (all the light-emitting elements 11 and 21 on the vdd panel will stop the previous screen A, two ^ Ϊ Ϊ Ϊ Ϊ 51 51 51 51 51 51 51 开始 开始 51 51 51 to start the current day frame 60 Current: Write operation, so that the voltage difference across the storage elements (C and C,) in the day element can be used to drive 7L T3 and T3, the current flowing is equal to the data current (丨 plus a) * = Vsg ( The source and gate voltage difference) are sequentially executed until the next g, and the scanning line 5 1 70 becomes the data current writing operation. After completing the writing period 601 of each scanning line 51, the common cathode line 53 is lowered. When it reaches the zero potential (GND) and enters the display period 602, the light-emitting elements in each pixel on the panel and the light-emitting elements 21 and 21 will pass the same current as the data current to write, so that the light-emitting elements 11 and 21 of the display emit the current The operating principle of the present invention is explained as follows: During the writing period 601, since the common cathode line 53 rises to a high potential (Vdd), the light emitting elements 11 and 21 cannot be illuminated due to the reverse bias, and flow through the light emitting element.丨 and 2 丨 the current becomes zero. So, When the scanning drive signal is sent from the scanning line 51, the control element T4 of 10 in the odd sub-pixels and the control element T4 of even-numbered sub-pixels 20 are turned on. “So, the signal on the odd-numbered enable line 1 0 1 will pass through The control element T4 is turned on to turn on the writing element T1 and the switching element T2 in the odd-numbered sub-pixel 10, and the signal on the even-numbered enable line 201 passes through the control element T4 to turn on to write in the even-numbered sub-pixel 20. The input element T1 'and the switching element T2 are turned off. At the same time, the data current (Idata_ ^ d) of the odd number of sub-days 10 will be sent on the data line 50. At this time, if the data current (Idata_Qdd) on the data line 50 Not equal to flow

Page 11 200428334

V. Description of the invention (8) After driving the current (In) of 70 pieces of 13, there will be a current (U to charge or discharge the storage element c, whose current is equal to the data current (!) And flowing through the driving element T3 The difference in current (IT3). Storage element c charges d $ — $ The action of electricity will increase or decrease the current (IT3) flowing through drive element T3, and the action of charging or discharging of storage element C will continue until When the magnitude of the current (IT3) flowing through the driving element T3 is equal to the data current (Idata_Qdd), and when the magnitude of the current (Iτ3) flowing through the driving element T3 is equal to the data current (Qdd) ', then both ends of the storage element c The voltage difference can provide the Vsg required for the driving element τ 3 flowing current (Iτ3) equal to the data current (Idafdd). Next, the signal on the odd-numbered enable line 101 will pass the control element T4 to make the odd number of days. The writing element T1 and the switching element in the prime 10 are turned off, and the signal on the even-numbered enable line 2 01 passes through the control element, thereby turning on the writing element τ 1 ′ and the switching in the even-numbered sub-pixel 20. Element τ 2 is turned on. At the same time A data current (τ ") of an even-numbered sub-day prime 2 0 will be sent on the shell material line 5 〇, 1 data_odd y # /-2, and / f material current (U is not equal to the current flow through the drive c ί W ( Ιτ3,), there will be a current (ic.) To charge or discharge the storage element c, the current is equal to the data current (

Idata_even) is different from the current (1) flowing through the driving element T3. The action of charging or discharging the storage element C 'will cause the current T T3; & Left + ^ ^ ^ n 丨 3 The current (IT3,) increases or decreases, and the storage element Cs is charged or discharged by the driving element T3. , The magnitude of the current ('), etc. 2). And when the current flowing through the drive element T3 is large:; etc .; when the T material current (Idata —even), at this time, C T3 is stored, and 70 pieces are stored. The voltage difference between the two ends can be hammered.

200428334

Vsg 'required for the driving element T3'. When the circulating current (IT3,) is equal to the data current d,), the element 51 should be a μ f after each scan-after writing, the common cathode line 53 is lowered to the zero potential Q (j MD) and enters significantly lower than pq r 〇 Γ) & "τ IT, s, between 6 0 2", so that the light-emitting elements 11 and 21 are in a forward bias and are turned on and off. Since the 饨 六 一 " ^ ^ 7α head is used to store the elements Cs and Cs, two The voltage difference at the terminals can be used to drive the components T3 and T3. The current flowing is equal to the data current, sg sg 'so the light-emitting elements in each pixel on the panel " and "will pass the same lightning as the writer's data # 一 'Beizhu ^ ^ Machine-sized current, so that the light-emitting elements 11 and 21 of the display emit the brightness required by the current picture.

To sum up, the current driving device of the active organic light emitting diode has the following advantages: (1) The technology of the present invention can realize the current programming driving method to compensate the thin film transistor (TFT) The device's threshold voltage (Threshold Voltage) and electron mobility (',

Mobility) to improve the unevenness of the image of the active organic light emitting diode panel.

(2) The technology of the present invention can save the number of data lines 50, only one half of the number of data lines 50 need to be familiar with the design. If so, it can save circuit costs, reduce the manufacturing cost of module system bonding (bonding), and increase the number of modules One of the robustness of the system connection (Robustness).

(3) The technology of the present invention does not need to use C-TFT LTPS process of P-Type and N-Type, and the manufacturing cost can be reduced. (4) The technology of the present invention will cause the organic light emitting diode element to be under reverse bias for a period of time during the operation day. In this operation mode, it can be increased.

200428334 V. Description of the Invention (ίο) Lifetime of Organic Light Emitting Diode Element. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. That is, all equal changes and modifications made in accordance with the scope of patent application for the present invention are covered by the scope of patent for the present invention.

Page 14 200428334 Brief description of the drawings [Simplified description of the drawings] Figure 1 is a schematic diagram of the device of the present invention. Figure 2 is the driving architecture of Figure 1. FIG. 3 is a schematic diagram of a pixel circuit of US Pat. No. 6,229,506. Figure 4 is the drive architecture of Figure 3. [Symbol description of the figure] Switching element T2, T2 'Control element T4, T4' Odd number of sub-days 1 0 Even number of sub-days 2 0 Even-numbered enable line 2 0 1 Data line 31, 50 Power supply line 33, 52 Frame 40, display 4 0 2 writing period 6 0 1 ^ 52 60 writing element T1, T Γ driving element T3, T3 'storage element Cs, C, C' light emitting element 11, 2 1 odd number enable Line 1 0 1 Transistor PI, P2, P3, N1 Scanning line 3 2, 5 1 Organic light emitting diode 34 Write operation 4 0 1 Common cathode line 5 3 Display period 6 0 2

Page 15

Claims (1)

200428334 VI. Scope of patent application: The current drive of the field-type organic light-emitting diodes made by the Department of Electrical and Mechanical Engineering is used.-Two adjacent children day element (odd number of sub-pixels and ~ 22: sub-drivers) Including: a series of odd-numbered enable lines; Yu j Zi-day: an even-numbered enable line; a scan line and a write element; a gate of a switching element; a drive element power supply line; a cathode line; the The source of the writing element (termed as the data line connected to the data line): the data line shared by the pixels and the even-numbered subdivision; 'The gate of the switching element is connected to the upper phase, and its source is connected to the data line The connection write 7 " is connected, and the source electrode thereof is: the pole is connected to the above-mentioned writing element-the control element = the supply line; the source electrode is connected to the above-mentioned odd number two: "gate and the scan Line-to-line connection, Bu Chong ^ you-to this line (even number of enabling lines) phase i ^ ^ above 70 switches are connected to the gate, 4 connections, its drain and a storage element, the source of the storage element Connected, another ::::: knows the above driving element The drain connection is connected; the gate of the driving element and the writing element are a light-emitting element, and the light-emitting element is widely connected, and the other end is the negative terminal and the above-mentioned driving element 2. For example, the scope of the patent application, the common cathode line phase The current driving device is connected to the active organic light emitting diode described above, and the input device is a thin film transistor. Page 16 200428334 3. The current-driven device as described in item 1 of the scope of the patent application, wherein the switching "a few light-emitting diodes are wrong. 4. The thin-film transistor as described in the item i of the scope of the patent application. "Let the diode 5. Thin film transistor as described in item i of the patent application. A current-driven device, wherein the control element is an organic light emitting diode 6. The active device is as described in item 1 of the scope of patent application: :: transistor. The current driving device, wherein the storage element = Storage Capacitor. * The method of storage and storage 7 includes a current driving method of an active organic light emitting diode, and the driving is a writing period. When driving, a diurnal frame cycle is divided into two periods, one is the display period; During the writing period, the common cathode line is raised to a high potential (Vdd), all the light on the panel, the component will stop the previous screen from lighting, and the current scanning of the current frame data is started from the first scanning line. Action, so that the voltage difference across the storage element in the day element can provide the driving element and the current Vsg (source and gate voltage difference) required when the current equals the data current (I data); complete the writing of each scan line After entering the period, the common cathode line is lowered to zero potential (GND) to enter the display period. The light-emitting elements in each pixel on the panel will pass the same current as the data current written to the display, so that the light-emitting elements of the display need to emit the picture. The brightness. Page 17