Patent Application
20180240405
This application claims priority to a Chinese patent application No. 201710096052.7, filed on Feb. 22, 2017, and entitled “Organic Light-Emitting Display Panel, Organic Light-Emitting Display Apparatus, and Driving Method of Organic Light-Emitting Display Panel”, the disclosure of which is incorporated herein by reference in entirety.
The present disclosure relates to the field of display, in particular to an organic light-emitting display panel, an organic light-emitting display apparatus, and a driving method of the organic light-emitting display panel.
In recent years, people have developed various light weight and small size flat panel display devices for replacing cathode ray tube. Examples of such flat panel display devices include a liquid crystal display panel, a plasma display panel and an electroluminescent display panel. The electroluminescent display panel realizes the normal display of the display panel through an electroluminescent device within the display panel. According to different materials of a light-emitting layer, electroluminescent devices are divided into two categories: inorganic light-emitting and organic light-emitting. The organic light-emitting device is referred to as a new generation of display technology, since the organic light-emitting device has a high response speed, a high luminous efficiency, a strong luminance, and a wide viewing angle.
A light-emitting device within the organic light-emitting display panel is a current driving light-emitting device whose light emission luminance is determined by a driving current of a driving transistor. There are large differences among various drive transistors due to factors such as working conditions, production process and the like, therefore, there exists a phenomenon of uneven screen among different pixels on the display panel due to a threshold voltage drift of the driving transistor. At present, in the existing art, the threshold voltage of the driving transistor is compensated generally by means of external compensation and internal compensation so as to eliminate the problem of uneven display caused by the threshold voltage drift. According to the external compensation, the threshold voltage of the driving transistor is acquired by an integrated process unit (other than the pixel driving circuit itself) of the organic light-emitting display panel, and then a data voltage is compensated based on the acquired threshold voltage. According to the internal compensation, the acquisition and compensation of the threshold voltage of the driving transistor is completed by the pixel driving circuit itself.
In practical applications, organic light-emitting display devices are often in an environment whose brightness is continually varying, it is urgent to adjust a display mode according to the brightness of the environment where the organic light-emitting display devices are located so as to compensate the luminance. Although both of the external compensation and the internal compensation can effectively overcome the problem of uneven screen generated due to the threshold voltage shit of the driving transistor, the luminance cannot be effectively compensated according to the environment brightness so as to improve an over bright or over dark visual experience appearing when being observed by human eyes.
In view of this, one of the objectives of the present disclosure is to provide an organic light-emitting display panel, a driving method of the organic light-emitting display panel. The organic light-emitting display panel can sense environment brightness quickly and adjust a light emission luminance of a display screen according to the environment brightness, thereby avoiding a problem of an over bright or over dark when being observed by human eyes.
According to an aspect of the present disclosure, there provides an organic light-emitting display panel including a data line and a gate line intersecting the data line; a switching signal line; a pixel driving circuit including a first voltage terminal for supplying a high-level direct current voltage, a driving transistor, a light-emitting diode and a photosensitive switch electrically connected between the first voltage terminal and the light-emitting diode, a control terminal of the photosensitive switch is electrically connected with the switching signal line; a photosensitive element disposed at a non-display region of the organic light-emitting display panel; and a control circuit including a storage module and a control module. The photosensitive element is configured to sense environment brightness and is electrically connected with the control circuit. The storage module of the control circuit is configured to store the environment brightness sensed by the photosensitive element. The control module controls a time duration of an enable signal on the switching signal line in a light-emitting phase based on the sensed environment brightness, and the enable signal is an electrical signal which turns on the photosensitive switch.
According to an aspect of the present disclosure, there provides a method for driving the above organic light-emitting display panel. The driving method includes a light-sensing phase and a light-emitting phase. In the light-sensing phase, the photosensitive element senses the environment brightness and transmits it to the control circuit, and the control circuit stores the sensed environment brightness in the storage module. In the light-emitting phases, the control module of the control circuit controls the time duration of the enable signal on the switching signal line based on the sensed environment brightness.
According to an aspect of the present disclosure, there provides an organic light-emitting display apparatus including the above organic light-emitting display panel.
Compared with the related art, according to the organic light-emitting display panel, the organic light-emitting display apparatus and the driving method of the organic light-emitting display panel, the photosensitive element is disposed in the non-display region and senses the brightness of the environment where the display panel is located in time, and transmits the sensed environment brightness information to the control circuit in time. The control circuit controls the length of conduction time of the photosensitive switch in the pixel driving circuit according to the sensed environment brightness, thus controls the light-emitting time of the light-emitting diode in the pixel circuit under different environment brightness so as to produce different accumulation of luminance in human eyes, thereby avoiding the problem of over bright or over dark when being observed by human eyes and realizing the luminance compensation simply and effectively.
In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the accompanying drawings, which are used in the description of the related art or the embodiments, are briefly described. Apparently, the accompanying drawings are some embodiments of the present disclosure, and other accompanying drawings may be obtained based on these accompanying drawings by those skilled in the art without paying inventive work.
In order to make the foregoing objects, features and advantages of the present disclosure more apparent and understandable, the disclosure will be further described below in conjunction with the accompanying drawings and embodiments.
It should be noted that specific details are set forth in the following description so as to fully understand the disclosure. However, the present disclosure may be embodied in various other manners which are different from that described herein, and those skilled in the art may make similar generalizations without departing from the spirit of the present disclosure. Therefore, the present disclosure is not limited to the specific embodiments disclosed below.
As shown in
In various embodiments, given that the driving transistor DT is kept being turned on in a light-emitting phase, the longer a time duration of an enable signal (an electrical signal for turning on the photosensitive switch GSW) conveyed on the switching signal line GL is, the longer a time duration of a conductive channel formed between the first voltage terminal PVDD and the light-emitting diode EL is, and the longer a luminescence time of the light-emitting diode EL is, the higher an accumulated light emission luminance is. Therefore, different light emission luminance of the organic light-emitting display panel is realized by means of controlling the time duration of the enable signal on the switching signal line GL.
Continuing to refer to
As shown in
Therefore, in the organic light-emitting display panel provided by these embodiments, the photosensitive element disposed at the non-display region senses in time the brightness of the environment where the display panel is located, and transmits the sensed environment brightness information to the control circuit in time, and the control circuit controls, according to the sensed environment brightness, the conducting duration of the photosensitive switch in the pixel driving circuit in the light-emitting phase so as to control the light-emitting time of the light-emitting diode in the pixel circuit under different environment brightness to produce different accumulated luminance, thereby avoiding a problem of over bright or over dark which occurs during the observation of human eyes and simply and effectively realizing the luminance compensation.
In a high-brightness environment, the organic light-emitting display panel needs to increase the corresponding light emission luminous so as to meet the needs of human eye observation, while in a low-brightness environment, the organic light-emitting display panel needs to reduce the corresponding light emission luminous so as to meet the needs of human eye observation. Therefore, the time duration of the enable signal on the switching signal line in the high-brightness environment is longer than the time duration of the enable signal on the switching signal line in the low-brightness environment under the control of the control circuit. Specifically, when the environment brightness is L1, the photosensitive element sense the environment brightness and transmits the sensed environment brightness information to the control circuit, and the control module of the control circuit processes the corresponding signal and controls the time duration of the enable signal to be T1; when the environment brightness is L2, the photosensitive element sense the environment brightness and transmits the sensed environment brightness information to the control circuit, and the control module of the control circuit processes the corresponding signal and controls the time duration of the enable signal to be T2. As shown in
Further, in the case where the overall light-emitting time is constant, the light-emitting time may be divided to reduce a flicker of the screen. As shown in
It should be noted that, in various embodiments, the photosensitive element 12 transmits the sensed environment brightness information to the control circuit 13. The environment brightness information refers to electrical signal information in one to one correspondence with the environment brightness information. For example, when the resistance value of the photosensitive element 12 varies with the variation of the environment brightness, the photosensitive element 12 is of different resistance values under different environment brightness, therefore, the sensing of different environment brightness can be realized by transmitting different resistance values to the control circuit.
Further, in order to realize the sensing of environment brightness more adequately, uniformly and efficiently, multiple locations of the non-display region of the organic light-emitting display panel are provided with the photosensitive element 12.
It should be noted that, the orientation terms such as “left”, “right” and the like, used in embodiments of the present disclosure are described according to the perspective of the accompanying drawings, and it should not be interpreted as a limitation to embodiments of the disclosure.
Optionally, as shown in
Optionally, the photosensitive element 12 may be arranged to a plurality of photosensitive sub elements which are electrically connected in series to one another, and disposed at the non-display region of the organic light-emitting display panel.
In the embodiment shown in
Optionally, the organic light-emitting display panel further includes a gate driving circuit, through which the control circuit is connected with the switching signal line.
Further, as shown in
Specifically, in the stage P1, the scan line SL and the second light-emitting control line EM2 are supplied with high-level signals, and the first light-emitting control line EM1 is supplied with a low-level signal. At this moment, under the control of high-level signals on the scan line SL, the second light-emitting control line EM2 and the switching signal line GL, the first transistor M1, the second transistor M2, the third transistor M3 and the photosensitive switch GSW are turned on. Meanwhile, the threshold voltage detection module 133 conveys an initial voltage signal Vinitial, the Vinitial is transmitted to the anode of the organic light-emitting diode EL through the first transistor M1 and the second transistor M2 which are turned on, and the anode of the organic light-emitting diode EL is initialized. Meanwhile, the reference voltage line Vref is transmitted to the second node N2 through the conductive third transistor M3. Therefore, in the stage P1, the voltage of the first node N1 is Vinitial, and the voltage of the second node N2 is Vref.
In the stage P2, the scan line SL, the first light-emitting control line EM1 are supplied with high-level signals, and the second light-emitting control line EM2 is supplied with the low-level signal. Meanwhile, under the control of the high-level signals of the scan line SL, the first light-emitting control line EM1, the first transistor M1, the fourth transistor M4 and the photosensitive switch GSW are turned on. Meanwhile, the driving transistor DT is turned on at this moment after the initialization of the previous stage. Therefore, the high-level direct current voltage PVDD supplied by the first voltage terminal PVDD is transmitted to the first node N1 through the fourth transistor M4, the photosensitive switch GSW, and the driving transistor DT which are turned on, so that the potential of the first node N1 keeps rising. The driving transistor DT is turned off when the potential of the first node N1 rises to Vref−Vth. The potential of the first node N1 is transmitted to the threshold voltage detection module 133 through the conducting driving transistor DT.
In the stage P3, a high-level signal is supplied to the scan line SL, low-level signals are supplied to the first light-emitting control line EM1 and the second light-emitting control line EM2. At this moment, under the control of the high-level signal of the scan line SL, the first transistor M and the third transistor M3 are turned on, the threshold voltage detection module 133 carries out a calculation process on the threshold voltage Vth obtained in the stage P2 and outputs a voltage of Vdata−Vth to the first node N1 (that is, the source electrode of the driving transistor DT) through the data line DL so as to accomplish the threshold voltage compensation of the driving transistor DT.
In the stage P4, high-level signals are supplied to the first light-emitting control line EM1 and the second light-emitting control line EM2, and a low-level signal is supplied to the scan line SL. At this moment, under the control of the high-level signals of the first light-emitting control line EM1 and the second light-emitting control line EM2, the fourth transistor M4 and the second transistor M2 are turned on. After the threshold voltage compensation in the previous stage, the driving transistor DT is turned on at this moment. The driving current I of the organic light-emitting diode EL is I=k*(Vgs−Vh)2=k*(Vref−Vdata)2, that is, the driving current of the organic light-emitting diode EL is not affected by the threshold voltage drift.
In the stage P4, the environment brightness differs, and the outputting time period TX of the enable signal (the high-level signal in
Therefore, the embodiment shown in
As shown in
Therefore, in order to ensure that the switching signal line GL is maintained at the high-level throughout the threshold voltage detection phase unlike the light-emitting phases in which the high-level signal varies with the variation of specific environment brightness, the control circuit of the embodiment of the present disclosure further includes a judgment module 134 for judging whether the threshold voltage detection module is carrying out the detection of the threshold voltage of the driving transistor. As shown in
It should be noted that,
It should be noted that the control circuit 13 of the embodiment of the present disclosure may be integrated with a function of transmitting data signal voltage to the data line. However, this is not limited by the present disclosure, and the data signal voltage on the data line DL may be controlled by other integrated circuits.
Moreover, the present disclosure further discloses a driving method of the organic light-emitting display panel for driving the organic light-emitting display panel described in each above embodiment.
As shown in
In step 901, in the light-sensing phase, the photosensitive element senses the environment brightness and transmits it to the control circuit, and the control circuit stores the sensed environment brightness in the storage module.
In step 902, in the light-emitting phase, the control module of the control circuit controls the time duration of the enable signal on the switching signal line based on the sensed environment brightness.
Specifically, in the step 901, the photosensitive element converts the sensed environment brightness information to electrical information and transmits the electrical information to the control circuit, and the corresponding electrical information is stored in the storage module. In the step 902, the control module of the control circuit calls the electrical information stored in the storage module, and obtains the time duration of the enable signal by processing. The time duration of the enable signal is T1 when the environment brightness sensed by the photosensitive element is L1; and the time duration of the enable signal is T2 when the environment brightness sensed by the photosensitive element is L2. T1 is greater than T2 when L1 is greater than L2. T1 is less than T2 when L1 is less than L2.
It should be noted that the control module may be configured with a table of “environment brightness—time duration of enable signal” in advance. Different environment brightness values correspond to different time durations of enable signal, and a high environment brightness value corresponds to a longer time duration of enable signal. As shown in Table 1, when the photosensitive element senses environment brightness LX, the brightness information LX is firstly converted into the corresponding electrical information RX which is transmitted to the storage module of the control circuit, and then the control module of the control circuit calls the Table 1 and find the time duration TX of the enable signal corresponding to the electrical information RX. Thus, when the organic light-emitting display panel is under different environment brightness, the time duration of the enable signal differs, and the light-emitting time of the light-emitting diode differs, and the final accumulated amount of the luminance in human eyes differs, thereby avoiding the over bright or over dark problem when being observed by human eyes.
Further, for a certain environment brightness, the time duration, corresponding to the certain environment brightness, of the enable signal on the switching signal line may be equally divided multiple times so as to reduce the flashing on the screen. For example, the time duration T1 may be equally divided into n sub time durations, the time duration T2 may be equally divided into m sub time durations, where n and m are integers greater than 2. In an embodiment, n is equal to m. In another embodiment, n and m are not equal.
Further, the driving method of the present embodiment further includes a threshold voltage detection phase.
As shown in
In step 1001, a light-sensing phase, the photosensitive element senses the environment brightness and transmits it to the control circuit, and the control circuit stores the sensed environment brightness into the storage module.
In step 1002, a threshold voltage detection phase, the control circuit outputs a stable enable signal to the switching signal line.
In step 1003, a light-emitting phase, the control module of the control circuit adjusts the time duration of the enable signal on the switching signal line based on the sensed environment brightness.
That is, the driving method provided by the embodiment is applicable to the organic light-emitting display panel with threshold voltage compensation. In order to ensure the successful proceeding of the threshold voltage compensation process, in the threshold voltage compensation process, the control circuit outputs a stable enable signal to the switch signal line regardless of the environment brightness. The specific pixel driving circuit is not limited by the present disclosure, and the specific process of the threshold voltage detection varies with the specific pixel driving circuit. Therefore, the specific process of the threshold voltage detection is not described in the description of the driving method of the present disclosure. Regardless of the design of the pixel circuit, in order to ensure the successful proceeding of the threshold voltage compensation process, in the threshold voltage compensation process, the control circuit outputs the stable enable signal to the switch signal line regardless of the environment brightness.
In addition, the present disclosure further provides an organic light-emitting display apparatus including the organic light-emitting display panel described in any above embodiment. The display apparatus includes a smart phone, a smart watch, a laptop and the like, which is not limited by the present disclosure.
According to the organic light-emitting display panel and the driving method of the organic light-emitting display panel provided by the embodiment, the photosensitive element disposed at the non-display region senses in time the brightness of the environment where the display panel is located, and transmits the sensed environment brightness information to the control circuit in time, and the control circuit controls, according to the sensed environment brightness, the conducting duration of the photosensitive switch in the pixel driving circuit in the light-emitting phase so as to control the light-emitting time of the light-emitting diode in the pixel circuit under different environment brightness to produce different accumulated luminance, thereby avoiding a problem of over bright or over dark which occurs during the observation of human eyes and simply and effectively realizing the luminance compensation.
The foregoing is a further detailed description of the present disclosure in connection with specific preferred embodiments, and it is not to determine that the specific implementation of the disclosure is limited to these descriptions. It will be apparent that several simple deductions or substitutions may be made by those skilled in the art without departing from the spirit of the present disclosure, and should be considered as falling within the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201710096052.7 | Feb 2017 | CN | national |
