Micro-display and driving method therefor

Abstract

A micro-display and a driving method therefor. The micro-display comprises: sub-pixels (10), wherein the sub-pixels (10) are connected to a first power supply end (VOLED) and a second power supply end (VCOM), the first power supply end (VOLED) is used for supplying a first voltage, and the second power supply end (VCOM) is used for supplying a second voltage. A working process of the micro-display comprises a first stage and a second stage, wherein in the first stage, the difference between the first voltage and the second voltage is a first difference, and in the second stage, the difference between the first voltage and the second voltage is a second difference and the sub-pixels (10) are in a non-light-emitting state; the first difference is greater than 0, the first difference is greater than a lighting voltage threshold of the sub-pixels (10), and the second difference is less than 0. The problem of aging of light-emitting devices can be mitigated, and the service life of the micro-display is prolonged.

Description

Microdisplay and driving method thereof

[0001] Cross-references

[0002] This application claims priority to the Chinese patent application filed on January 31, 2024, with application number "202410138073.0" and invention name "Microdisplay and its driving method", the entire content of which is incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of display technology, and in particular to a micro display and a driving method thereof. Background Art

[0004] Microdisplays are relatively small and are a crucial component of virtual reality (VR) and augmented reality (AR) devices. For example, a microdisplay is one with a screen size less than 30mm diagonally. Silicon-based organic light-emitting diode (OLED) microdisplays offer advantages over other microdisplays, including high resolution, high integration, low power consumption, compact size, and light weight. Using single-crystal silicon as an active drive backplane, they boast higher carrier mobility and are expected to become a key solution for next-generation smart wearable displays.

[0005] However, continuously lighting the OLED device will cause localized charge accumulation, and the aging of the light-emitting material will reduce the brightness, accelerate the life decay of the light-emitting device, and reduce the service life of the silicon-based OLED display.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a micro display and a driving method thereof, which can improve the aging problem of light-emitting devices and increase the service life of the micro display.

[0008] In a first aspect, an embodiment of the present application provides a microdisplay, comprising: a sub-pixel, the sub-pixel being connected to a first power supply terminal and a second power supply terminal, the first power supply terminal being used to provide a first voltage, and the second power supply terminal being used to provide a second voltage; the working process of the microdisplay 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-luminous 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.

[0009] In a possible embodiment of the first aspect, within a frame time of the microdisplay, an operation process of the microdisplay includes multiple bit planes, and within the bit plane, data of each row of sub-pixels is written, illuminated, and cleared row by row, and the time interval between writing and clearing the sub-pixel data is the data writing time of row i, where i is the weight of the bit plane;

[0010] The first stage includes any bit plane, and the second stage is between adjacent bit planes.

[0011] In a possible embodiment of the first aspect, the microdisplay operates within a frame time including multiple bit planes, the bit planes including a first time period and a second time period, wherein data of each row of sub-pixels is written row by row during the first time period, and multiple rows of sub-pixels are displayed according to the written data during the second time period;

[0012] The first phase includes the second period, and the second phase includes the first period.

[0013] In a possible embodiment of the first aspect, in the first stage, a voltage value of the first voltage is V11, and a voltage value of the second voltage is V12;

[0014] In the second stage, the voltage value of the first voltage is V21, and the voltage value of the second voltage is V22;

[0015] V11≠V21, and / or, V12≠V22.

[0016] In a possible embodiment of the first aspect, |V11-V21|≠|V12-V22|.

[0017] In a possible embodiment of the first aspect, |V11-V21|<|V12-V22|.

[0018] In a possible embodiment of the first aspect, the sub-pixel includes a first sub-pixel and a second sub-pixel having different luminous colors;

[0019] The second difference corresponding to the first sub-pixel is ΔV2_p1, and the second difference corresponding to the second sub-pixel is ΔV2_p2;

[0020] ΔV2_p1≠ΔV2_p2.

[0021] In a possible embodiment of the first aspect, the decay rate of the light-emitting material of the first sub-pixel is smaller than the decay rate of the light-emitting material of the second sub-pixel, |ΔV2_p1|<|ΔV2_p2|.

[0022] In a possible embodiment of the first aspect, the first sub-pixel includes a green sub-pixel, and the second sub-pixel includes a red sub-pixel or a blue sub-pixel;

[0023] Alternatively, the first sub-pixel includes a red sub-pixel, and the second sub-pixel includes a blue sub-pixel.

[0024] In a second aspect, an embodiment of the present application provides a driving method for a microdisplay, wherein the microdisplay includes sub-pixels, the sub-pixels are connected to a first power supply terminal and a second power supply terminal, the first power supply terminal is used to provide a first voltage, and the second power supply terminal is used to provide a second voltage;

[0025] The working process of the microdisplay includes the first and second stages;

[0026] Drive methods include:

[0027] In the first stage, the difference between the first voltage and the second voltage is controlled to be a first difference;

[0028] In the second stage, the difference between the first voltage and the second voltage is controlled to be a second difference, and the sub-pixel is controlled to be in a non-luminous state; wherein 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.

[0029] According to the microdisplay and its driving method provided by the embodiments of the present application, since the first difference between the first voltage and the second voltage is greater than 0 in the first stage and the second difference between the first voltage and the second voltage is less than 0 in the second stage, the voltage difference across the sub-pixel can be switched between positive and negative voltages, thereby controlling the sub-pixel's light-emitting device to switch between forward bias voltage and reverse bias voltage, changing the charge distribution within the light-emitting device, slowing the aging of the light-emitting device, and increasing the service life of the microdisplay. In addition, since the first difference is greater than the sub-pixel's lighting voltage threshold, the sub-pixel is ready for luminescence in the first stage, thereby improving the aging problem of the light-emitting device in the sub-pixel without affecting the sub-pixel's luminescence. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects and advantages of the present application will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which the same or similar reference numerals represent the same or similar features and the accompanying drawings are not drawn to scale.

[0031] FIG1a shows a schematic diagram of an equivalent circuit of a sub-pixel in a micro-display provided by an embodiment of the present application;

[0032] FIG1 b shows a schematic diagram of an equivalent circuit of a sub-pixel in a micro-display provided in an embodiment of the present application;

[0033] FIG2 is a schematic diagram showing a driving process of a microdisplay provided in an embodiment of the present application;

[0034] FIG3 is a schematic diagram showing another driving process of a microdisplay provided in an embodiment of the present application;

[0035] FIG4 is a schematic diagram showing another driving process of the microdisplay provided in an embodiment of the present application;

[0036] FIG5 is a schematic diagram showing another driving process of the microdisplay provided in an embodiment of the present application;

[0037] FIG6 is a schematic diagram showing a life test of a microdisplay provided in an embodiment of the present application;

[0038] FIG7 shows a schematic flow chart of a method for driving a microdisplay according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0040] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0041] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0042] In the embodiments of the present application, the term "connect" may refer to a direct connection between two components or an electrical connection between two components via one or more other components. The term "drive" may refer to "control" or "operate."

[0043] It will be apparent to those skilled in the art that various modifications and variations can be made in this application without departing from the spirit or scope of this application. Therefore, this application is intended to cover modifications and variations of this application that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents. It should be noted that the embodiments provided in the examples of this application can be combined with each other without contradiction.

[0044] The embodiments of the present application provide a micro display and a driving method thereof. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0045] First, the microdisplay provided in the embodiments of the present application is introduced.

[0046] The microdisplay provided in the embodiments of the present application includes a silicon-based microdisplay, and specifically, the microdisplay includes a digitally driven silicon-based microdisplay that uses digital signals to control display.

[0047] A microdisplay may include multiple sub-pixels, each of which is referred to as a pixel. For a digitally driven microdisplay, the equivalent circuit of a single sub-pixel may be as shown in FIG1a or FIG1b . 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 to provide a first voltage, and the second power supply terminal VCOM is used to provide a second voltage. The voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM controls the brightness of the sub-pixel.

[0048] Exemplarily, the sub-pixel 10 may include a pixel circuit 11 and a light-emitting device 12. As shown in FIG1a , the pixel circuit 11 is connected between the first power supply terminal VOLED and the anode of the light-emitting device 12, and the cathode of the light-emitting device 12 is connected to the second power supply terminal VCOM. Alternatively, as shown in FIG1b , 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 include at least one control switch, and the gate of the control switch may be connected to a data signal. For example, the gate of the control switch may be connected to a pulse-width modulation (PWM) signal. It should be noted that the pixel circuit 11 shown in FIG1a and FIG1b includes a control switch, which is merely an example and is not intended to limit the specific structure of the pixel circuit 11.

[0049] The operation process of the microdisplay may include a first stage and a second stage; in the first stage, the difference between the first voltage and the second voltage is the first difference; in the second stage, the difference between the first voltage and the second voltage is the second difference, and the sub-pixel is in a non-luminous state; the first difference is greater than 0 and 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.

[0050] According to the microdisplay provided by the embodiments of the present application, since the first difference between the first voltage and the second voltage is greater than 0 in the first stage and less than 0 in the second stage, the voltage difference across the subpixel can be switched between positive and negative voltages, thereby controlling the subpixel's light-emitting device to switch between forward bias voltage and reverse bias voltage, changing the charge distribution within the light-emitting device, slowing the aging of the light-emitting device, and increasing the service life of the microdisplay. In addition, since the first difference is greater than the subpixel's lighting voltage threshold, the subpixel is ready for luminescence in the first stage, thereby improving the aging of the light-emitting device in the subpixel without affecting the subpixel's luminescence.

[0051] As an example, during the operation of the microdisplay, the number of first phases and second phases may be equal, each first phase may be followed by a second phase, or each second phase may be followed by a first phase.

[0052] As another example, the number of first stages may be greater than the number of second stages, and multiple second stages may be evenly interspersed between multiple first stages.

[0053] It is 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 can be in a forward bias voltage. When the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative, the light-emitting device can be in a negative bias voltage. Under negative bias voltage, the light-emitting device generates a weak reverse saturation current, driving internal carrier redistribution. The negative voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM can be understood as a process of correcting the charge distribution of the light-emitting device.

[0054] In some embodiments, the microdisplay can use a rolling illumination mode for scanning and display. This mode uses a row-by-row writing and clearing method. That is, after writing a row of data signals, the control switch is immediately turned on for display. Once the display is complete, the row of data is immediately cleared. Each row of sub-pixels is operated simultaneously, and the row clearing interval is an integer multiple of the row writing time.

[0055] Specifically, within a microdisplay frame, the microdisplay's operating process may include multiple bit planes. Within each bit plane, data for each row of subpixels is written, illuminated, and cleared row by row. The time interval between subpixel data writing and clearing is the data writing time for row i, where i is the weight of the bit plane. The first stage includes any bit plane, and the second stage occurs between adjacent bit planes.

[0056] A bit plane period is a subfield, and each bit plane period has its own corresponding weight. Taking 256 grayscale levels as an example, a 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.

[0057] To better illustrate the scrolling display mode, as shown in FIG2 , the display process of 10 rows of sub-pixels in a micro display is taken as an example. For example, the weight of the first bit plane is 1. In the first bit plane, the data corresponding to the sub-pixels in the 1st to 10th rows are written sequentially. When the data writing of the sub-pixels in the 2nd row is completed, the data of the sub-pixels in the first row are controlled to be cleared. The time interval between displaying and clearing is the time interval between writing one row of data. The weight of the second bit plane is 2. In the second bit plane, the data corresponding to the sub-pixels in the 1st to 10th rows are written sequentially. When the data writing of the sub-pixels in the 3rd row is completed, the data of the sub-pixels in the first row are controlled to be cleared. The time interval between displaying and clearing is the time interval between writing two rows of data. And so on.

[0058] In the embodiment of the present application, during the scrolling display scanning process, additional bit plane data is further inserted between any two bit planes. The number of additional bit planes inserted in each frame is greater than or equal to 1, and the bit plane display data is all '1', turning on the control switch. This phase is referred to as the second phase. However, during the second phase, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is adjusted to a negative voltage for a duration of Tn. 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, effectively applying a reverse bias voltage to the light-emitting device. This drives carrier redistribution within the light-emitting device, generating a weak reverse saturation current. During normal bit plane data display, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is switched to a positive voltage, activating the microdisplay. The duration of the second phase (Tn), the weight of the inserted bit plane data, and the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM can be adjusted as needed.

[0059] For example, as shown in FIG3 , the scrolling display scanning process is described using the display process of 10 rows of sub-pixels in a microdisplay. The first bit plane and the second bit plane can each be represented by two first phases. Additional bit plane data is inserted between the first bit plane and the second bit plane, and this inserted bit plane represents the second phase. In the first and second bit planes, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is positive and greater than the lighting voltage threshold. In this inserted bit plane, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative.

[0060] In other embodiments, the microdisplay may adopt a non-clear line scanning display mode, the principle of which is to write the data of a certain plane of the entire screen into the sub-pixels in a black screen state, and then make the sub-pixels of the entire screen light up or not according to the written data.

[0061] Specifically, within a frame time, the microdisplay operates through multiple bit planes, with at least one bit plane including a first period and a second period. During the first period, data for each row of sub-pixels is written row by row, and during the second period, multiple rows of sub-pixels display data based on the written data. The first period includes the second period, and the second period includes the first period.

[0062] During data writing, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is at least below the lighting voltage threshold, the sub-pixel does not emit light, and the microdisplay turns off. When the data writing process is complete, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is increased to exceed the lighting voltage difference threshold, driving the sub-pixel to illuminate. After the display time reaches the set pulse width, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM drops below the voltage threshold, and the next bit plane data is transmitted. The pulse width that drives the sub-pixel to illuminate is called the bit plane weight.

[0063] To better illustrate the unclear row scanning display mode, as shown in Figure 4, the display process of 10 rows of sub-pixels in a microdisplay is used as an example. In the first bit plane, the time occupied by the 10 black-filled boxes represents the first period, and the display time with a weight of 1 CLK represents the second period. In the first period, the data corresponding to the sub-pixels in rows 1 to 10 are written sequentially. During the data writing process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is 0V, which is lower than the lighting voltage threshold. The sub-pixels do not emit light, and the microdisplay turns off. After the data for the 10th row is written, in the second period, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is increased to exceed the lighting voltage threshold, the sub-pixels light up, and the microdisplay displays. The display time weight of the first bit plane is 1 clock pulse (CLK). In the second bit plane, the time occupied by the ten black-filled boxes represents the first period, and the display time with a weight of 2 CLK represents the second period. During the first period, the data corresponding to the sub-pixels in rows 1 through 10 are sequentially written. During this data writing process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is 0V, below the lighting voltage threshold. The sub-pixels do not emit light, and the microdisplay turns off. After the data for row 10 is written, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is increased to above the lighting voltage threshold, causing the sub-pixels to illuminate and the microdisplay to display. The display time weight of the second bit plane is 2 clock pulses (CLK). And so on.

[0064] In the embodiment of the present application, during the unclear line scanning display process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is further set to a negative voltage during the first period of the bit plane, and the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is set to a positive voltage during the second period of the bit plane. In other words, during the unclear line scanning display process, during the data writing process of the bit plane, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is set to a negative voltage, and after the data writing is completed, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is set to a positive voltage. In this way, during the data writing process, the internal carriers of the light-emitting device are rearranged, and the generated saturation current drives the carriers to shift, thereby changing the charge distribution within the light-emitting device, slowing down the aging of the light-emitting device, and increasing the service life of the microdisplay.

[0065] As shown in Figure 5, the display process of 10 rows of sub-pixels in a microdisplay is used as an example to illustrate the digital drive unclear row display process and improve the life of the microdisplay. In the first bit plane, the time occupied by 10 black-filled boxes represents the first period, and the display time with a weight of 1CLK represents the second period. In the first period, the data corresponding to the sub-pixels in rows 1 to 10 are written sequentially. During the data writing process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative. The voltage difference amplitude between 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 microdisplay is turned off. After the 10th row of data is written, in the second period, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is increased to be higher than the lighting voltage threshold, the sub-pixels are lit, and the microdisplay is displayed. In the second bit plane, the time occupied by the ten black-filled boxes represents the first period, and the display time with a weight of 2 CLK represents the second period. During the first period, the data corresponding to the sub-pixels in rows 1 through 10 are sequentially written. During this data writing process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is negative, and the voltage difference between 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 microdisplay turns off. After the data for row 10 is written, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is increased to exceed the lighting voltage threshold, the sub-pixels turn on, and the microdisplay displays. The display time weight of the second bit plane is 2 clock pulses (CLK). And so on.

[0066] To verify the effect of switching the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM between positive and negative voltages on the lifespan of the microdisplay, the inventors conducted tests to verify the relationship between display brightness over time under a white screen, with the initial brightness of the light-emitting devices remaining the same. The test results are shown in Figure 6, where the horizontal axis represents time and the vertical axis represents brightness. As time increases, the smaller the decrease in brightness, the longer the lifespan.

[0067] Curve T311-4 is a test result of a silicon-based microdisplay being continuously lit, that is, the sub-pixels in the silicon-based microdisplay are always in a light-emitting state.

[0068] Curve T311 - 7 is a test result of lighting the display screen in a simulated scrolling display mode. During the display process, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is maintained at +6V.

[0069] Curve T311-6 shows the test results of a negative voltage display lighting test with an additional plane of data added in a simulated scrolling display mode. When displaying data, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is +6V. After the data display is completed, the additional plane of data is inserted, and the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is -1.8V.

[0070] Test results show that, compared to a continuously lit silicon microdisplay driving method, using a scrolling display mode can extend the lifespan of the silicon microdisplay. Furthermore, inserting additional bit plane data and creating a negative voltage difference between the first power supply terminal, VOLED, and the second power supply terminal, VCOM, can offset overcharging, partially releasing the charge and further extending the lifespan of the silicon microdisplay.

[0071] As an 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.

[0072] Of course, in other examples, the absolute value of the first difference can be set to be less than or equal to the absolute value of the second difference as required. In other words, the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is a positive voltage, or it can be less than or equal to the voltage difference between the first power supply terminal VOLED and the second power supply terminal VCOM is a negative voltage.

[0073] In some embodiments, the voltage of at least one of the first power terminal VOLED and the second power terminal VCOM may be adjusted so that the difference between the first power terminal VOLED and the second power terminal VCOM switches between a positive voltage and a negative voltage.

[0074] 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 terminal VOLED is V21, and the voltage value of the second voltage of the second power supply terminal VCOM is V22; V11≠V21, and / or, V12≠V22.

[0075] Wherein, V11≠V21 and / or V12≠V22 may include the following three situations:

[0076] In case 1, V11≠V21, and V12≠V22, that is, the voltages of the first power terminal VOLED and the second power terminal VCOM are both adjusted.

[0077] Case 2: V11≠V21, and V12=V22, that is, the voltage of the first power terminal VOLED is adjusted, and the voltage of the second power terminal VCOM is not adjusted.

[0078] Case three: V11=V21, and V12≠V22, that is, the voltage of the first power terminal VOLED is not regulated, and the voltage of the second power terminal VCOM is regulated.

[0079] In some embodiments, |V11 - V21| ≠ |V12 - V22|. That is, the voltage range of the first power supply terminal VOLED differs from the voltage range of the second power supply terminal VCOM. As shown in Figure 1a, the first power supply terminal VOLED is connected to the anode of the light-emitting device 22 via a control switch. The difference between the gate voltage of the control switch and the voltage of the first power supply terminal VOLED affects the state of the control switch. A switch may not be provided between the second power supply terminal VCOM and the cathode of the light-emitting device.

[0080] In the embodiment of the present application, when |V11-V21|≠|V12-V22|, the requirements of both the light-emitting device and the control switch can be taken into account.

[0081] Of course, in other examples, |V11-V21|=|V12-V22| can also be set. 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.

[0082] In some embodiments, |V11-V21|<|V12-V22|, that is, the voltage variation range of the first power terminal VOLED is smaller than the voltage variation range of the second power terminal VCOM.

[0083] As shown in FIG1a , 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." Data "1" turns the control switch on, and data "0" turns the control switch off. The voltage amplitudes corresponding to data "1" and data "0" are generally fixed. 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 place the control switch in the desired state. In the embodiment of the present application, the voltage variation range of the first power supply terminal VOLED is small. In other words, this facilitates placing the control switch in the desired state without adjusting the voltage amplitude of the PWM pulse signal.

[0084] A microdisplay may include multiple subpixels. As an example, in the equivalent circuit structure of a subpixel as shown in Figure 1a, the cathodes of the multiple subpixels of the microdisplay may constitute a surface electrode. In other words, the multiple subpixels may be connected to the same second power supply terminal VCOM. The anodes of different subpixels are generally independent of each other, so different subpixels may be connected to different first power supply terminals VOLED, and the voltages of the different first power supply terminals VOLED connected to different subpixels may be adjusted differently.

[0085] As another example, in the equivalent circuit structure of a subpixel as shown in Figure 1b, the anodes of multiple subpixels of a microdisplay can form a surface electrode. That is, multiple subpixels can be connected to the same first power supply terminal, VOLED. The cathodes of different subpixels can be independent, so different subpixels can be connected to different second power supply terminals, VCOM, and the voltages of the different second power supply terminals, VCOM, connected to different subpixels can be adjusted differently.

[0086] Of course, in other examples, it can also be set to |V11-V21|>|V12-V22|, that is, the voltage variation range of the first power terminal VOLED is greater than the voltage variation range of the second power terminal VCOM.

[0087] In some embodiments, the subpixels of the micro display include a first subpixel and a second subpixel with different luminous colors. The second difference corresponding to the first subpixel is ΔV2_p1, and the second difference corresponding to the second subpixel is ΔV2_p2; ΔV2_p1≠ΔV2_p2.

[0088] The first sub-pixel and the second sub-pixel having different luminous colors have different working states and different charge distributions. When the charge distributions of the first sub-pixel and the second sub-pixel are adjusted using the same negative voltage difference, the negative voltage may be too large or too small for one of them.

[0089] In the embodiment of the present application, ΔV2_p1≠ΔV2_p2. Thus, different negative voltage differences can be used to adjust the charge distribution states of the first and second sub-pixels, respectively, thereby flexibly matching the different requirements of the first and second sub-pixels. This helps reduce the difference between the first and second sub-pixels, preventing one from having an excessively large or small negative voltage. Therefore, the lifespans of the first and second sub-pixels can be better adjusted, improving 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.

[0090] Of course, in other examples, it may also be set as ΔV2_p1=ΔV2_p2, and / or ΔV1_p1=ΔV1_p2.

[0091] In some embodiments, the decay rate of the light-emitting material of the first sub-pixel is slower than that of the light-emitting material of the second sub-pixel, where |ΔV2_p1|<|ΔV2_p2|. The slower the decay rate of the light-emitting material of the sub-pixel, the smaller the negative voltage difference can be used to adjust the lifespan of the sub-pixel.

[0092] If other characteristics of the light-emitting material of the sub-pixel are taken into consideration, in other examples, it may also be set to |ΔV2_p1|>|ΔV2_p2|.

[0093] In some embodiments, the microdisplay may include a red subpixel, a green subpixel, and a blue subpixel. The first subpixel may include a green subpixel and the second subpixel may include a red subpixel or a blue subpixel; or the first subpixel may include a red subpixel and the second subpixel may include a blue subpixel.

[0094] Generally, the green sub-pixel's luminescent material decays slowly, and the amplitude of the negative voltage difference can be the smallest; the blue sub-pixel's luminescent material decays fastest, and the amplitude of the negative voltage difference can be the largest; and the amplitude of the negative voltage difference of the red sub-pixel can be between the two.

[0095] If other characteristics of the light-emitting materials of the sub-pixels are taken into consideration, in other examples, for example, the first sub-pixel may include a blue sub-pixel, and the second sub-pixel may include a red sub-pixel or a green sub-pixel.

[0096] Based on the same inventive concept, an embodiment of the present application further provides a driving method for a microdisplay. The microdisplay includes a sub-pixel. As shown in FIG1 , 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 to provide a first voltage, and the second power supply terminal VCOM is used to provide a second voltage. The operation process of the microdisplay includes a first stage and a second stage.

[0097] As shown in FIG. 7 , the driving method of the micro display includes S10 and S20 .

[0098] S10, in the first stage, controlling the difference between the first voltage and the second voltage to be a first difference;

[0099] S20, in the second stage, controlling the difference between the first voltage and the second voltage to be a second difference, and controlling the sub-pixel to be in a non-luminous state, wherein the first difference is greater than 0 and greater than a lighting voltage threshold of the sub-pixel, and the second difference is less than 0.

[0100] According to the driving method of the microdisplay provided in the embodiment of the present application, since the first difference between the first voltage and the second voltage is greater than 0 in the first stage and the second difference between the first voltage and the second voltage is less than 0 in the second stage, the voltage difference across the sub-pixel can be switched between positive and negative voltages, thereby controlling the light-emitting device of the sub-pixel to switch between forward bias voltage and reverse bias voltage, changing the charge distribution within the light-emitting device, slowing the aging of the light-emitting device, and increasing the service life of the microdisplay. In addition, since the first difference is greater than the lighting voltage threshold of the sub-pixel, the sub-pixel is ready for luminescence in the first stage, thereby improving the aging problem of the light-emitting device in the sub-pixel without affecting the luminescence of the sub-pixel.

[0101] In some embodiments, a method for driving a microdisplay includes:

[0102] In one frame, the working process of the microdisplay is divided into multiple bit planes. Within each bit plane, the data of each row of sub-pixels is controlled to be written, illuminated, and cleared row by row. The time interval between the writing and clearing of sub-pixel data is the data writing time of row i, where i is the weight of the bit plane.

[0103] The first stage includes any bit plane, and the second stage is located between adjacent bit planes.

[0104] In some embodiments, a method for driving a microdisplay includes:

[0105] In one frame time, the working process of the micro display is divided into multiple bit planes, and the bit plane includes a first period and a second period. In the first period, the data of each row of sub-pixels is controlled to be written row by row. In the second period, the sub-pixels of multiple rows are controlled to display according to the written data.

[0106] The first phase includes the second period, and the second phase includes the first period.

[0107] In some embodiments, a method for driving a microdisplay includes:

[0108] The absolute value of the first difference is controlled to be greater than the absolute value of the second difference.

[0109] In some embodiments, a method for driving a microdisplay includes:

[0110] In the first stage, the voltage value of the first voltage is controlled to be V11, and the voltage value of the second voltage is controlled to be V12;

[0111] In the second stage, the voltage value of the first voltage is controlled to be V21, and the voltage value of the second voltage is controlled to be V22;

[0112] V11≠V21, and / or, V12≠V22.

[0113] In some embodiments, a method for driving a microdisplay includes:

[0114] Control |V11-V21|≠|V12-V22|.

[0115] In some embodiments, a method for driving a microdisplay includes:

[0116] Control |V11-V21|<|V12-V22|.

[0117] In some embodiments, the sub-pixels include a first sub-pixel and a second sub-pixel having different luminescent colors;

[0118] The driving method of the microdisplay includes:

[0119] Control the second difference corresponding to the first sub-pixel to be ΔV2_p1, and control the second difference corresponding to the second sub-pixel to be ΔV2_p2;

[0120] ΔV2_p1≠ΔV2_p2.

[0121] In some embodiments, the decay rate of the light-emitting material of the first sub-pixel is lower than the decay rate of the light-emitting material of the second sub-pixel, and the driving method of the micro display includes:

[0122] Control |ΔV2_p1|<|ΔV2_p2|.

[0123] In some embodiments, a method for driving a microdisplay includes:

[0124] The blue sub-pixel is used as the first sub-pixel, and the red sub-pixel or the green sub-pixel is used as the second sub-pixel;

[0125] Alternatively, the red sub-pixel is used as the first sub-pixel, and the green sub-pixel is used as the second sub-pixel.

[0126] It should be noted that the microdisplay provided in the embodiments of the present application can be a wearable product or other display products with display functions such as mobile phones.

[0127] While the embodiments described above are not exhaustive, they do not limit the present application to the specific embodiments described. Clearly, numerous modifications and variations are possible based on the above description. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present application, thereby enabling those skilled in the art to better utilize the present application and its modifications. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. A microdisplay, characterized in that: include: a sub-pixel, wherein the sub-pixel is connected to a first power supply terminal and a second power supply terminal, wherein the first power supply terminal is used to provide a first voltage, and the second power supply terminal is used to provide a second voltage; The working process of the micro display includes 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-luminous state; The first difference is greater than 0, and the first difference is greater than a lighting voltage threshold of the sub-pixel, and the second difference is less than 0.

2. The microdisplay according to claim 1, wherein: The microdisplay has a working process within one frame time including a plurality of bit planes, wherein the data of the sub-pixels in each row are written, illuminated, and cleared row by row in the bit plane, and the time interval between writing and clearing the data of the sub-pixels is the data writing time of row i, where i is the weight of the bit plane; The first stage includes any one of the bit planes, and the second stage is located between adjacent bit planes.

3. The microdisplay according to claim 1, wherein: The microdisplay has a working process within one frame time including a plurality of bit planes, wherein the bit planes include a first period and a second period, wherein data of the sub-pixels in each row are written row by row during the first period, and wherein the sub-pixels in the plurality of rows are displayed according to the written data during the second period; The first phase includes the second period, and the second phase includes the first period.

4. The microdisplay according to claim 1, wherein: 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 according to claim 4, wherein: |V11-V21|≠|V12-V22|.

6. The microdisplay according to claim 5, wherein: |V11-V21|<|V12-V22|.

7. The microdisplay according to claim 1, wherein: The sub-pixels include a first sub-pixel and a second sub-pixel having different luminous colors; The second difference corresponding to the first sub-pixel is ΔV2_p1, and the second difference corresponding to the second sub-pixel is ΔV2_p2; ΔV2_p1≠ΔV2_p2.

8. The microdisplay according to claim 7, wherein: The decay rate of the light emitting material of the first sub-pixel is smaller than the decay rate of the light emitting material of the second sub-pixel, |ΔV2_p1|<|ΔV2_p2|.

9. The microdisplay according to claim 8, wherein: The first sub-pixel includes a green sub-pixel, and the second sub-pixel includes a red sub-pixel or a blue sub-pixel; Alternatively, the first sub-pixel includes a red sub-pixel, and the second sub-pixel includes a blue sub-pixel.

10. A method for driving a microdisplay, characterized in that: The micro display includes a sub-pixel, and the sub-pixel is connected to a first power supply terminal and a second power supply terminal, the first power supply terminal is used to provide a first voltage, and the second power supply terminal is used to provide a second voltage; The working process of the micro display includes a first stage and a second stage; The driving method includes: In the first stage, controlling the difference between the first voltage and the second voltage to be a first difference; In the second stage, the difference between the first voltage and the second voltage is controlled to be a second difference, and the sub-pixel is controlled to be in a non-luminous state; wherein, 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.

Images