CN117975885A - Micro display and driving method thereof - Google Patents

Abstract

The application discloses a micro display and a driving method thereof. The micro display includes: the sub-pixel is connected with a first power end and a second power end, the first power end is used for providing a first voltage, and the second power end is used for providing a second voltage; the working process of the micro display comprises a first stage and a second stage; in the first stage, the difference between the first voltage and the second voltage is a first difference; in the second stage, the difference between the first voltage and the second voltage is a second difference, and the sub-pixel is in a non-light-emitting state; the first difference is greater than 0, and the first difference is greater than the lighting voltage threshold of the sub-pixel, and the second difference is less than 0. According to the embodiment of the application, the aging problem of the light-emitting device can be improved, and the service life of the micro display can be prolonged.

Description

Micro display and driving method thereof

Technical Field

The application relates to the technical field of display, in particular to a micro display and a driving method thereof.

Background

The microdisplay is relatively small in size and is an important component of a Virtual Reality (VR) device or an augmented Reality (Augmented Reality, AR) device. For example, a microdisplay refers to a display with a display screen diagonal size of less than 30 mm. Compared with other micro-displays, the Organic LIGHT EMITTING Diode (OLED) micro-display based on silicon substrate has the advantages of high resolution, high integration level, low power consumption, small volume, light weight and the like, and the OLED micro-display based on silicon substrate uses monocrystalline silicon as an active driving backboard, has higher carrier mobility and is expected to become a main scheme of next-generation intelligent wearable display.

However, continuous lighting of the OLED device may cause localized charge accumulation, degradation of the luminescent material may reduce brightness, accelerate decay of the light emitting device lifetime, and reduce the lifetime of the silicon-based OLED display.

Disclosure of Invention

The embodiment of the application provides a micro display and a driving method thereof, which can improve the aging problem of a light-emitting device and prolong the service life of the micro display.

In a first aspect, an embodiment of the present application provides a microdisplay, including: the sub-pixel is connected with a first power end and a second power end, the first power end is used for providing a first voltage, and the second power end is used for providing a second voltage; the working process of the micro display comprises a first stage and a second stage; in the first stage, the difference between the first voltage and the second voltage is a first difference; in the second stage, the difference between the first voltage and the second voltage is a second difference, and the sub-pixel is in a non-light-emitting state; the first difference is greater than 0, and the first difference is greater than the lighting voltage threshold of the sub-pixel, and the second difference is less than 0.

In one possible embodiment of the first aspect, the operation of the micro display includes a plurality of bit planes, in which data of each row of sub-pixels is written, emitted and cleared row by row, and a time interval between writing and clearing data of the sub-pixels is a data writing time of i rows, where i is a weight of the bit plane;

The first phase includes any one bit plane and the second phase is located between adjacent bit planes.

In a possible embodiment of the first aspect, the operation of the micro display includes a plurality of bit planes in a frame time, the bit planes including a first period in which data of each row of sub-pixels is written row by row and a second period in which the rows of sub-pixels are displayed according to the written data;

The first phase includes a second period of time and the second phase includes a first period of time.

In a possible embodiment of the first aspect, in the first stage, the voltage value of the first voltage is V11, and the voltage value of the second voltage is V12;

In the second stage, the voltage value of the first voltage is V21, and the voltage value of the second voltage is V22;

V11+.v21, and/or v12+.v22.

In a possible embodiment of the first aspect, |v11-v21| noteq|v12-v22|.

In a possible embodiment of the first aspect, |v11-v21| < |v12-v22|.

In a possible embodiment of the first aspect, the sub-pixels comprise a first sub-pixel and a second sub-pixel with different emission colors;

The second difference value corresponding to the first sub-pixel is DeltaV2_p1, and the second difference value corresponding to the second sub-pixel is DeltaV2_p2;

ΔV2_p1≠ΔV2_p2。

In a possible embodiment of the first aspect, the decay rate of the luminescent material of the first sub-pixel is smaller than the decay rate of the luminescent material of the second sub-pixel, |Δv2_p1| < |Δv2_p2|.

In a possible embodiment of the first aspect, the first sub-pixel comprises a green sub-pixel and the second sub-pixel comprises a red sub-pixel or a blue sub-pixel;

or the first sub-pixel comprises a red sub-pixel and the second sub-pixel comprises a blue sub-pixel.

In a second aspect, an embodiment of the present application provides a method for driving a micro display, where the micro display includes a sub-pixel, the sub-pixel is connected to a first power terminal and a second power terminal, the first power terminal is configured to provide a first voltage, and the second power terminal is configured to provide a second voltage;

The working process of the micro display comprises a first stage and a second stage;

The driving method comprises the following steps:

in the first stage, controlling the difference value of the first voltage and the second voltage to be a first difference value;

In the second stage, controlling the difference value of the first voltage and the second voltage to be a second difference value, and controlling the sub-pixels to be in a non-luminous state; the first difference is greater than 0, and the first difference is greater than the threshold of the lighting voltage of the sub-pixel, and the second difference is less than 0.

According to the micro display and the driving method thereof provided by the embodiment of the application, as the first difference value between the first voltage and the second voltage is larger than 0 in the first stage and the second difference value between the first voltage and the second voltage is smaller than 0 in the second stage, the differential pressure between two ends of the sub-pixel can be switched between positive pressure and negative pressure, the light emitting device of the sub-pixel can be controlled to be switched between positive bias voltage and negative bias voltage, the charge distribution in the light emitting device is changed, the aging speed of the light emitting device is slowed down, and the service life of the micro display is prolonged. In addition, since the first difference is larger than the lighting voltage threshold of the sub-pixel, the sub-pixel has the lighting condition in the first stage, so that the aging problem of the light emitting device in the sub-pixel can be improved on the premise of not influencing the lighting of the sub-pixel.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar features, and in which the figures are not to scale.

FIG. 1a is a schematic diagram of an equivalent circuit of a subpixel in a micro-display according to an embodiment of the present application;

FIG. 1b is a schematic diagram of an equivalent circuit of a subpixel in a micro-display according to an embodiment of the present application;

FIG. 2 is a schematic diagram showing a driving process of a micro display according to an embodiment of the present application;

FIG. 3 is a schematic diagram showing another driving process of a micro display according to an embodiment of the present application;

FIG. 4 is a schematic diagram showing a driving process of a micro display according to an embodiment of the present application;

FIG. 5 is a schematic diagram showing a driving process of a micro display according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a life test of a micro display according to an embodiment of the present application;

fig. 7 is a schematic flow chart of a driving method of a micro display according to an embodiment of the application.

Detailed Description

Features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail below with reference to the accompanying drawings and the detailed embodiments. It should be understood that the specific embodiments described herein are merely configured to illustrate the application and are not configured to limit the application. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the application by showing examples of the application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In embodiments of the present application, the term "connected" may refer to two components being directly connected, or may refer to two components being electrically connected via one or more other components. The term "drive" may refer to "control" or "operation".

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Accordingly, it is intended that the present application covers the modifications and variations of this application provided they come within the scope of the appended claims (the claims) and their equivalents. The embodiments provided by the embodiments of the present application may be combined with each other without contradiction.

Embodiments of the present application provide a micro display and a driving method thereof, and various embodiments of the present application will be described with reference to the accompanying drawings.

First, the micro display provided by the embodiment of the application is described.

The micro-display provided by the embodiment of the application comprises a silicon-based micro-display, and particularly comprises a digital driving silicon-based micro-display. The digital driving silicon-based micro-display uses digital signals to control display.

The microdisplay may include a plurality of subpixels, one of which may be referred to as a pixel point. For a digital driving type micro display, as shown in fig. 1a or 1b, an equivalent circuit of a single sub-pixel may be shown, where the sub-pixel 10 is connected to a first power supply terminal VOLED and a second power supply terminal VCOM, the first power supply terminal VOLED is used for providing a first voltage, the second power supply terminal VCOM is used for providing a second voltage, and a voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM controls brightness intensity of the sub-pixel.

For example, the sub-pixel 10 may include a pixel circuit 11 and a light emitting device 12, as shown in fig. 1a, the pixel circuit 11 is connected between a first power supply terminal VOLED and an anode of the light emitting device 12, and a cathode of the light emitting device 12 is connected to a second power supply terminal VCOM. Alternatively, as shown in fig. 1b, the pixel circuit 11 is connected between the second power supply terminal VCOM and the cathode of the light emitting device 12, and the anode of the light emitting device 12 is connected to the first power supply terminal VOLED. The light emitting device 12 may be an OLED device. The pixel circuit 11 may comprise at least one control switch, the gate of which may be connected to a data signal, for example a Pulse-Width Modulation (PWM) signal. It should be noted that the pixel circuit 11 shown in fig. 1a and 1b includes a control switch, which is only an example, and is not intended to limit the specific structure of the pixel circuit 11.

The operation of the micro-display may include a first stage and a second stage; in the first stage, the difference between the first voltage and the second voltage is a first difference; in the second stage, the difference between the first voltage and the second voltage is a second difference, and the sub-pixel is in a non-light-emitting state; the first difference is greater than 0, and the first difference is greater than the lighting voltage threshold of the sub-pixel, and the second difference is less than 0. That is, in the first stage, the first difference between the first power supply terminal VOLED and the second power supply terminal VCOM is greater than 0 and greater than the lighting voltage threshold, and in the second stage, the second difference between the first power supply terminal VOLED and the second power supply terminal VCOM is less than 0.

According to the micro display provided by the embodiment of the application, as the first difference value between the first voltage and the second voltage is larger than 0 in the first stage and the second difference value between the first voltage and the second voltage is smaller than 0 in the second stage, the voltage difference between two ends of the sub-pixel can be switched between positive voltage and negative voltage, the light emitting device of the sub-pixel can be controlled to be switched between forward bias voltage and reverse bias voltage, the charge distribution in the light emitting device is changed, the aging speed of the light emitting device is slowed down, and the service life of the micro display is prolonged. In addition, since the first difference is larger than the lighting voltage threshold of the sub-pixel, the sub-pixel has the lighting condition in the first stage, so that the aging problem of the light emitting device in the sub-pixel can be improved on the premise of not influencing the lighting of the sub-pixel.

As an example, during operation of the microdisplay, the number of first and second phases may be equal, one second phase may follow each first phase, or one first phase may follow each second phase.

As another example, the number of first stages may be greater than the number of second stages, and the plurality of second stages may be uniformly interspersed between the plurality of first stages.

It can be understood that, when the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is positive, the light emitting device may be at a positive bias voltage, and when the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative, the light emitting device may be at a negative bias voltage, and the light emitting device generates a weak reverse saturation current under the negative bias voltage to drive the internal carriers to be redistributed. The negative pressure of the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM can be understood as a correction process of the charge distribution of the light emitting device.

In some embodiments, the microdisplay may employ a scrolling (Rolling Illumination) mode for scanning display. The scrolling mode uses a mode of writing data signals line by line and clearing the data signals line by line to perform scanning display, namely, after writing a row of data signals, a control switch is turned on immediately to perform display, and the line data can be cleared immediately after the display is completed. And operating one row of sub-pixels at the same time, wherein the clear row interval time is an integral multiple of the time for writing one row of data.

Specifically, the micro-display may include a plurality of bit planes in a frame time, in which data of each row of sub-pixels is written, emitted and cleared row by row, and a time interval between writing and clearing of data of the sub-pixels is a data writing time of i rows, where i is a weight of the bit plane. Wherein the first phase comprises any one bit plane and the second phase is located between adjacent bit planes.

One bit plane period is a subfield, and each bit plane period has a respective weight. Taking 256 gray scales as an example, one frame time can be divided into 8 subfields, and the weight sequence of the 8 subfields is 128:64:32:16:8:4:2:1.

To better illustrate the scrolling mode, as shown in fig. 2, taking the display process of the 10 rows of sub-pixels in the micro display as an example, for example, the weight of the first bit plane is 1, in the first bit plane, data corresponding to the 1 st row to the 10 th row of sub-pixels are sequentially written, when the data writing of the 2 nd row of sub-pixels is completed, the data of the first row of sub-pixels is controlled to be cleared, and the display and clearing time interval is 1 row of data writing time; the weight value of the second bit plane is 2, in the second bit plane, data corresponding to the 1 st row to 10 th row of sub pixels are sequentially written, when the data writing of the 3 rd row of sub pixels is completed, the data of the first row of sub pixels are controlled to be cleared, and the time interval between the display and the clearing is 2 rows of data writing time; and so on.

In the embodiment of the present application, in the process of scrolling scanning, additional bit plane data is further inserted between any two bit planes, the number of additional bit planes inserted in each frame of picture is greater than or equal to 1, and the bit plane display data is '1', so as to turn on the control switch, and this stage is the second stage. However, in the second stage, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is adjusted to be negative, the duration is Tn, and during this period, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is lower than the lighting voltage threshold, and the light emitting device is equivalent to being applied with a reverse bias voltage, so that the internal carriers of the light emitting device can be driven to be redistributed, and weak reverse saturation current is generated. In the normal bit plane data display process, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is switched to positive voltage, and the micro display can be lightened for display. The duration time Tn of the second stage, the weight of the inserted bit plane data, and the voltage difference amplitude of the first power supply terminal VOLED and the second power supply terminal VCOM can be adjusted according to requirements.

For example, as shown in fig. 3, by taking the display process of 10 rows of sub-pixels in the micro-display as an example, the scroll display scanning process is described, the first bit plane and the second bit plane may be respectively two first phases, and additional bit plane data is inserted between the first bit plane and the second bit plane, and the inserted bit plane is the second phase. In the first bit plane and the second bit plane, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is positive voltage and is larger than the lighting voltage threshold value, and in the inserted bit plane, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is negative voltage.

In other embodiments, the micro-display may employ an unclear line scanning display mode, which is based on the principle that, in a black screen state, data of a certain bit plane of the whole screen is written into the sub-pixels, and then the sub-pixels of the whole screen are turned on or off according to the written data.

Specifically, in a frame time of the micro display, the working process of the micro display comprises a plurality of bit planes, at least one bit plane comprises a first period and a second period, data of each row of sub-pixels is written row by row in the first period, and a plurality of rows of sub-pixels are displayed according to the written data in the second period. Wherein the first phase comprises a second period of time and the second phase comprises a first period of time.

In the process of writing data, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is at least lower than the threshold value of the lighting voltage, the sub-pixels do not emit light, and the micro-display is turned off. After the data writing process is completed, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is higher than the threshold value of the lighting voltage difference, the sub-pixels are driven to be lighted, and after the display time reaches the set pulse width, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is reduced to be lower than the threshold value of the voltage, and then the next bit plane data is sent. The pulse width driving the lit sub-pixel is referred to as the bit-plane weight.

To better illustrate the unclear line scan display mode, as shown in fig. 4, taking the display process of 10 lines of subpixels in the micro-display as an example, in the first bit plane, the time occupied by 10 black filled boxes represents a first period, the display time of weight=1clk represents a second period, in the first period, data corresponding to the 1 st line to the 10 th line of subpixels are sequentially written, in the process of writing data, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is 0V, which is lower than the threshold of the lighting voltage, the subpixels do not emit light, and the micro-display is turned off. After the writing of the 10 th row of data is completed, in a second period, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is increased to be higher than the threshold value of the lighting voltage, the sub-pixels are lighted, the micro-display displays, and the display time weight of the first bit plane is 1 clock pulse (CLK). In the second bit plane, the time occupied by 10 black filled frames represents a first period, the display time of the weight=2clk represents a second period, data corresponding to the sub-pixels in the 1 st row to the 10 th row are sequentially written in the first period, during the data writing process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is 0V, the voltage difference is lower than the lighting voltage threshold, the sub-pixels do not emit light, and the micro display is turned off. After the writing of the 10 th row of data is completed, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is increased to be higher than the threshold value of the lighting voltage, the sub-pixels are lighted, the micro-display displays, and the display time weight of the second bit plane is 2 clock pulses (CLK); and so on.

In the embodiment of the application, in the process of scanning and displaying the unclear lines, the pressure difference between the first power supply end VOLED and the second power supply end VCOM is made to be negative in a first period of the bit plane, and the pressure difference between the first power supply end VOLED and the second power supply end VCOM is made to be positive in a second period of the bit plane. That is, when the scan display is performed, the differential voltage between the first power supply terminal VOLED and the second power supply terminal VCOM is set to be negative in the data writing process of the bit plane, and after the data writing is completed, the differential voltage between the first power supply terminal VOLED and the second power supply terminal VCOM is set to be positive, so that the internal carriers of the light emitting device are rearranged in the data writing process, the generated saturated current drives the carriers to shift, thereby changing the charge distribution inside the light emitting device, slowing down the aging speed of the light emitting device, and improving the service life of the micro display.

By way of example, as shown in fig. 5, a display process of 10 rows of subpixels in a microdisplay is taken as an example, and a digitally driven unclear row display process is described to improve the life of the microdisplay. In the first bit plane, the time occupied by 10 black filled frames represents a first period, the display time of the weight=1clk represents a second period, data corresponding to the sub-pixels in the 1 st row to the 10 th row are sequentially written in the first period, in the process of writing data, the differential pressure between the first power supply end VOLED and the second power supply end VCOM is negative pressure, the differential pressure amplitude of the first power supply end VOLED and the second power supply end VCOM is lower than the lighting voltage threshold, the sub-pixels do not emit light, and the micro display is turned off. After the writing of the 10 th row of data is completed, in a second period, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is increased to be higher than the threshold value of the lighting voltage, the sub-pixels are lighted, and the micro-display displays. In the second bit plane, the time occupied by the 10 black filled frames represents a first period, the display time of the weight=2clk represents a second period, data corresponding to the sub-pixels in the 1 st row to the 10 th row are sequentially written in the first period, in the process of writing data, the differential pressure between the first power supply terminal VOLED and the second power supply terminal VCOM is negative pressure, the differential pressure amplitude of the first power supply terminal VOLED and the second power supply terminal VCOM is lower than the lighting voltage threshold, the sub-pixels do not emit light, and the micro display is turned off. After the writing of the 10 th row of data is completed, the voltage difference between the first power supply end VOLED and the second power supply end VCOM is increased to be higher than the threshold value of the lighting voltage, the sub-pixels are lighted, the micro-display displays, and the display time weight of the second bit plane is 2 clock pulses (CLK); and so on.

In order to verify the influence of the voltage difference between the first power supply end VOLED and the second power supply end VCOM on the service life of the micro-display, the inventor also performs a test, and verifies that the initial brightness values of the light-emitting devices are the same in the time-varying relation of the brightness of the display screen under a white picture, the test result is shown in fig. 6, the horizontal axis represents time in fig. 6, and the vertical axis represents brightness. As time increases, if the degree of brightness reduction is small, the lifetime thereof is relatively longer.

The curve T311-4 is a test result of continuous lighting of the silicon-based micro-display, that is, the sub-pixels in the silicon-based micro-display are always in a light-emitting state.

The curve T311-7 is the test result of the simulated scrolling mode lighting display, and the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is kept at +6v during the display process.

The curve T311-6 is a test result of adding a negative pressure lighting display screen of additional plane data in the simulated rolling display mode, when the data is displayed, the pressure difference between the first power supply end VOLED and the second power supply end VCOM is +6V, after the data display is completed, the additional bit plane data is inserted, and the pressure difference amplitude between the first power supply end VOLED and the second power supply end VCOM is-1.8V.

Test results show that compared with a driving method for continuously lighting the silicon-based micro-display, the service life of the silicon-based micro-display can be prolonged through a rolling display mode. And on the basis, extra bit plane data are inserted, and the pressure difference between the first power supply end VOLED and the second power supply end VCOM is negative pressure, so that the overcharge phenomenon can be counteracted, partial charges are released, and the service life of the silicon-based micro-display is further prolonged.

As one example, the absolute value of the first difference is greater than the absolute value of the second difference. That is, the magnitude of the positive voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is greater than the magnitude of the negative voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM.

Of course, in other examples, the absolute value of the first difference may be set to be less than or equal to the absolute value of the second difference as desired. That is, the magnitude of the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is positive, or may be smaller than or equal to the magnitude of the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative.

In some embodiments, the voltage of at least one of the first power supply terminal VOLED and the second power supply terminal VCOM may be adjusted such that the difference between the first power supply terminal VOLED and the second power supply terminal VCOM switches between positive and negative voltages.

Specifically, in the first stage, the voltage value of the first voltage of the first power supply terminal VOLED is V11, and the voltage value of the second voltage of the second power supply terminal VCOM is V12; in the second stage, the voltage value of the first voltage of the first power supply end VOLED is V21, and the voltage value of the second voltage of the second power supply end VCOM is V22; v11+.v21, and/or v12+.v22.

Wherein v11+.v21, and/or v12+.v22 may include the following three cases:

In the first case, v11+.v21, v12+.v22, i.e. the voltages of the first power supply terminal VOLED and the second power supply terminal VCOM are regulated.

In case two, v11+.v21, and v12=v22, i.e. the voltage of the first power supply terminal VOLED is adjusted, and the voltage of the second power supply terminal VCOM is not adjusted.

In case three, v11=v21, and v12+.v22, i.e. the voltage of the first power supply terminal VOLED is not regulated and the voltage of the second power supply terminal VCOM is regulated.

In some embodiments, |v11-v21|noteq|v12-v22|. That is, the voltage variation range of the first power supply terminal VOLED is different from the voltage variation range of the second power supply terminal VCOM. As shown in fig. 1a, the first power terminal VOLED is connected to the anode of the light emitting device 22 through a control switch, and the difference between the gate voltage of the control switch and the voltage of the first power terminal VOLED affects the state of the control switch. No switch may be provided between the second power supply terminal VCOM and the cathode of the light-emitting device.

In the embodiment of the application, under the condition that the I V11-V21I is not equal to the I V12-V22I, the requirements of the light emitting device and the control switch can be met.

Of course, in other examples, it may also be set to |v11-v21|= |v12-v22|. That is, the voltage variation range of the first power supply terminal VOLED is the same as the voltage variation range of the second power supply terminal VCOM.

In some embodiments, |v11-v21| < |v12-v22|. That is, the voltage variation range of the first power supply terminal VOLED is smaller than the voltage variation range of the second power supply terminal VCOM.

As shown in fig. 1a, the gate of the control switch is connected to a data signal, the data signal may include a PWM pulse signal, the PWM pulse signal may include data "1" and data "0", the data "1" may turn on the control switch, the data "0" may turn off the control switch, and voltage amplitudes corresponding to the data "1" and the data "0" are generally fixed, and if the voltage variation range of the first power supply terminal VOLED is large, it may be necessary to further adjust the voltage amplitude of the PWM pulse signal to enable the control switch to be in a desired state. In the embodiment of the application, the voltage variation range of the first power supply terminal VOLED is smaller, that is, the control switch can be in a required state under the condition of not adjusting the voltage amplitude of the PWM pulse signal.

The microdisplay may include a plurality of subpixels. As an example, in the case that the equivalent circuit structure of the sub-pixels is shown in fig. 1a, the cathodes of the plurality of sub-pixels of the micro-display may form the plane electrode, that is, the plurality of sub-pixels may be connected to the same second power supply terminal VCOM. The anodes of the different sub-pixels are usually independent of each other, so that the different sub-pixels can be connected to different first power supply terminals VOLED, and the voltages of the different first power supply terminals VOLED connected to the different sub-pixels can be adjusted differently.

As another example, in the case that the equivalent circuit structure of the sub-pixels is shown in fig. 1b, the anodes of the plurality of sub-pixels of the micro-display may constitute the plane electrode, that is, the plurality of sub-pixels may be connected to the same first power source terminal VOLED. The cathodes of the different sub-pixels may be independent of each other, so that the different sub-pixels may be connected to different second power supply terminals VCOM, and the voltages of the different second power supply terminals VCOM connected to the different sub-pixels may be adjusted differently.

Of course, in other examples, it may also be set to |V11-V21| > |V12-V22|. That is, the voltage variation range of the first power supply terminal VOLED is larger than the voltage variation range of the second power supply terminal VCOM.

In some embodiments, the subpixels of the microdisplay include first and second subpixels having different colors of emission. The second difference value corresponding to the first sub-pixel is DeltaV2_p1, and the second difference value corresponding to the second sub-pixel is DeltaV2_p2; Δv2_p1+.Δv2_p2.

The first sub-pixel and the second sub-pixel with different light-emitting colors have different working states, and the charge distribution of the first sub-pixel and the second sub-pixel also have different charge distribution, and the charge distribution of the first sub-pixel and the second sub-pixel is adjusted by using the same negative voltage difference, so that the negative voltage can be too large or too small for one of the first sub-pixel and the second sub-pixel.

In the embodiment of the application, the delta V2-p 1 is not equal to the delta V2-p 2, so that the charge distribution states of the first sub-pixel and the second sub-pixel can be respectively adjusted by using different negative voltage differences, thereby flexibly matching different requirements of the first sub-pixel and the second sub-pixel, being beneficial to reducing the difference between the first sub-pixel and the second sub-pixel, being capable of avoiding the overlarge or undersize negative voltage of one of the first sub-pixel and the second sub-pixel, being capable of better adjusting the service lives of the first sub-pixel and the second sub-pixel and improving the design rationality. For example, the first difference corresponding to the first sub-pixel is Δv1_p1, and the first difference corresponding to the second sub-pixel is Δv1_p2; Δv1_p1+.Δv1_p2.

Of course, in other examples, Δv2_p1=Δv2_p2, and/or Δv1_p1=Δv1_p2 may also be set.

In some embodiments, the decay rate of the luminescent material of the first subpixel is less than the decay rate of the luminescent material of the second subpixel, |Δv2_p1| < |Δv2_p2|. The smaller the decay rate of the luminescent material of a subpixel, the lifetime of the subpixel can be adjusted with a negative voltage difference of smaller magnitude.

In other examples, it may also be set to |Δv2_p1| > |Δv2_p2|, if considered from other characteristics of the luminescent material of the sub-pixel.

In some embodiments, the microdisplay may include red, green, and blue subpixels. The first sub-pixel comprises a green sub-pixel, and the second sub-pixel comprises a red sub-pixel or a blue sub-pixel; or the first sub-pixel comprises a red sub-pixel and the second sub-pixel comprises a blue sub-pixel.

Typically, the light emitting material of the green sub-pixel decays slowly, the magnitude of the negative voltage difference may be minimal, the light emitting material of the blue sub-pixel decays the most, the magnitude of the negative voltage difference may be maximal, and the magnitude of the negative voltage difference of the red sub-pixel may be intermediate.

In other examples, the first subpixel may comprise a blue subpixel and the second subpixel may comprise a red subpixel or a green subpixel, if considered from other characteristics of the luminescent material of the subpixels.

Based on the same inventive concept, the embodiment of the present application further provides a driving method of a micro display, where the micro display includes a sub-pixel, as shown in fig. 1, the sub-pixel 10 is connected to a first power supply terminal VOLED for providing a first voltage and a second power supply terminal VCOM for providing a second voltage. The working process of the micro display comprises a first stage and a second stage;

as shown in fig. 7, the driving method of the micro display includes S10 and S20.

S10, in a first stage, controlling the difference value of the first voltage and the second voltage to be a first difference value;

S20, in the second stage, controlling the difference value of the first voltage and the second voltage to be a second difference value, and controlling the sub-pixel to be in a non-luminous state. The first difference is greater than 0, and the first difference is greater than the threshold of the lighting voltage of the sub-pixel, and the second difference is less than 0.

According to the driving method of the micro display provided by the embodiment of the application, as the first difference value between the first voltage and the second voltage is larger than 0 in the first stage and the second difference value between the first voltage and the second voltage is smaller than 0 in the second stage, the differential pressure between two ends of the sub-pixel can be switched between positive pressure and negative pressure, the light-emitting device of the sub-pixel can be controlled to be switched between positive bias voltage and negative bias voltage, the charge distribution in the light-emitting device is changed, the ageing speed of the light-emitting device is reduced, and the service life of the micro display is prolonged. In addition, since the first difference is larger than the lighting voltage threshold of the sub-pixel, the sub-pixel has the lighting condition in the first stage, so that the aging problem of the light emitting device in the sub-pixel can be improved on the premise of not influencing the lighting of the sub-pixel.

In some embodiments, a driving method of a micro display includes:

Dividing the working process of the micro display into a plurality of bit planes in one frame time, controlling the data of each row of sub-pixels to be written, emitted and cleared row by row in the bit planes, wherein the time interval for controlling the data writing and clearing of the sub-pixels is the data writing time of i rows, and i is the weight of the bit planes;

wherein the first phase comprises any one bit plane and the second phase is located between adjacent bit planes.

In some embodiments, a driving method of a micro display includes:

Dividing the working process of the micro display into a plurality of bit planes in one frame time, wherein the bit planes comprise a first time period and a second time period, the first time period controls the data of each row of sub-pixels to be written line by line, and the second time period controls the plurality of rows of sub-pixels to be displayed according to the written data;

The first phase includes a second period of time and the second phase includes a first period of time.

In some embodiments, a driving method of a micro display includes:

the absolute value of the first difference is controlled to be larger than the absolute value of the second difference.

In some embodiments, a driving method of a micro display includes:

In the first stage, controlling the voltage value of the first voltage to be V11 and controlling the voltage value of the second voltage to be V12;

In the second stage, controlling the voltage value of the first voltage to be V21 and controlling the voltage value of the second voltage to be V22;

V11+.v21, and/or v12+.v22.

In some embodiments, a driving method of a micro display includes:

Control |v11-v21| is not equal to |v12-v22|.

In some embodiments, a driving method of a micro display includes:

Control |v11-v21| < |v12-v22|.

In some embodiments, the subpixels include a first subpixel and a second subpixel having different emission colors;

The driving method of the micro display includes:

controlling the second difference value corresponding to the first sub-pixel to be delta V2-p 1, and controlling the second difference value corresponding to the second sub-pixel to be delta V2-p 2;

ΔV2_p1≠ΔV2_p2。

in some embodiments, the decay rate of the luminescent material of the first subpixel is less than the decay rate of the luminescent material of the second subpixel, the method of driving the microdisplay comprises:

control |Δv2_p1| < |Δv2_p2|.

In some embodiments, a driving method of a micro display includes:

the blue sub-pixel is used as a first sub-pixel, and the red sub-pixel or the green sub-pixel is used as a second sub-pixel;

or the red sub-pixel is used as a first sub-pixel, and the green sub-pixel is used as a second sub-pixel.

It should be noted that, the micro display provided by the embodiment of the application can be a wearable product or other display products with display functions such as a mobile phone.

These embodiments are not exhaustive of all details, nor are they intended to limit the application to the precise embodiments disclosed, in accordance with the application. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the application and the practical application, to thereby enable others skilled in the art to best utilize the application and various modifications as are suited to the particular use contemplated. The application is limited only by the claims and the full scope and equivalents thereof.

Claims (10)

1. A microdisplay, comprising:

the display device comprises a sub-pixel, a first power supply terminal and a second power supply terminal, wherein the sub-pixel is connected with the first power supply terminal and the second power supply terminal, the first power supply terminal is used for providing a first voltage, and the second power supply terminal is used for providing a second voltage;

The working process of the micro display comprises a first stage and a second stage;

In the first stage, the difference between the first voltage and the second voltage is a first difference;

In the second stage, the difference between the first voltage and the second voltage is a second difference, and the sub-pixel is in a non-light-emitting state;

the first difference is greater than 0, the first difference is greater than the threshold of the lighting voltage of the sub-pixel, and the second difference is less than 0.

2. The microdisplay of claim 1, wherein the display is configured to display the image of the object,

The micro display comprises a plurality of bit planes in the working process of the micro display in one frame time, wherein in the bit planes, data of each row of sub pixels are written, emitted and cleared row by row, the time interval of data writing and clearing of the sub pixels is the data writing time of i rows, and i is the weight of the bit planes;

The first stage includes any one of the bit planes, and the second stage is located between adjacent ones of the bit planes.

3. The microdisplay of claim 1, wherein the display is configured to display the image of the object,

The micro-display comprises a plurality of bit planes in the working process of the micro-display in one frame time, wherein the bit planes comprise a first time period and a second time period, data of all rows of sub-pixels in the first time period are written line by line, and a plurality of rows of sub-pixels in the second time period are displayed according to the written data;

the first phase includes the second period of time, and the second phase includes the first period of time.

4. The microdisplay of claim 1, wherein the display is configured to display the image of the object,

In the first stage, the voltage value of the first voltage is V11, and the voltage value of the second voltage is V12;

In the second stage, the voltage value of the first voltage is V21, and the voltage value of the second voltage is V22;

V11+.v21, and/or v12+.v22.

5. The microdisplay of claim 4, wherein the display is configured to display the image of the object,

|V11-V21|≠|V12-V22|。

6. The microdisplay of claim 5, wherein the display is configured to display the image of the object,

|V11-V21|＜|V12-V22|。

7. The microdisplay of claim 1, wherein said subpixels comprise first and second subpixels having different colors of emission;

The second difference value corresponding to the first sub-pixel is Δv2_p1, and the second difference value corresponding to the second sub-pixel is Δv2_p2;

ΔV2_p1≠ΔV2_p2。

8. The microdisplay of claim 7, wherein the display is configured to display the image of the object,

The decay rate of the luminescent material of the first sub-pixel is smaller than the decay rate of the luminescent material of the second sub-pixel, |Δv2_p1| < |Δv2_p2|.

9. The microdisplay of claim 8, wherein the first subpixel comprises a green subpixel and the second subpixel comprises a red subpixel or a blue subpixel;

Or the first sub-pixel comprises a red sub-pixel and the second sub-pixel comprises a blue sub-pixel.

10. The driving method of the micro display is characterized in that the micro display comprises a sub-pixel, wherein the sub-pixel is connected with a first power end and a second power end, the first power end is used for providing a first voltage, and the second power end is used for providing a second voltage;

The working process of the micro display comprises a first stage and a second stage;

The driving method includes:

In the first stage, controlling the difference value of the first voltage and the second voltage to be a first difference value;

in the second stage, controlling the difference between the first voltage and the second voltage to be a second difference, and controlling the sub-pixels to be in a non-light-emitting state; the first difference value is greater than 0, the first difference value is greater than the lighting voltage threshold of the sub-pixel, and the second difference value is less than 0.