Patent Grant
11984072
The present disclosure claims priority to the Chinese Patent Application No. 202010538367.4, filed to China Patent Office on Jun. 12, 2020, and entitled “DISPLAY PANEL, DISPLAY APPARATUS AND METHOD FOR DETERMINING CHANNEL WIDTH-TO-LENGTH RATIO OF SWITCH DEVICE”, the entire content of which is incorporated herein by reference.
The present disclosure relates to the technical field of display substrates, in particular to a display substrate and a design method therefor, and a display apparatus.
Currently, organic light-emitting diode (OLED) display products are diversified, customized specially shaped products are increasingly popular, and a specially shaped display screen is becoming a trend.
However, different regions of a customized specially shaped product vary in data payload, which results in different voltage loss of data signals. Such difference is particularly obvious in specially shaped display substrates in medium and large sizes, and is prone to causing a problem of uneven brightness of a screen, therefore affecting a display effect.
In a first aspect, an embodiment of the present disclosure provides a display substrate, including:
In one possible implementation, the display substrate is a specially shaped substrate; and at least two regions in the specially shaped substrate include at least one of: different shapes, different areas or different curvatures.
In one possible implementation, the design data payload of the region is positively correlated with a parasitic capacitance of each of the switch devices, the parasitic capacitance of the each switch device is a result of a first result divided by a second result, the first result is a result of a voltage loss of a data signal output by a data signal line multiplied by a parasitic capacitance on the data signal line, and the second result is a result of a voltage difference between a high level and a low level of the data signal minus the voltage loss of the data signal.
In one possible implementation, one region includes at least two data signal lines, one of the data signal lines is electrically connected to one column of the pixel circuits, one data switching circuit includes at least two switch devices, and each of the switch devices are equal in the channel width-to-length ratio.
In one possible implementation, one region includes a first data signal line, a second data signal line, a first pixel circuit electrically connected to the first data signal line, and a second pixel circuit electrically connected to the second data signal line;
In one possible implementation, a control end of the first switch device is electrically connected to a first control signal line, a first end of the first switch device is electrically connected to a data input line, and a second end of the first switch device is electrically connected to the first data signal line; and
In one possible implementation, one pixel circuit includes: a first switch circuit, a second switch circuit, a third switch circuit, a driving circuit, a light emitting control circuit, a storage device and a light emitting device;
In one possible implementation, the first switch circuit includes a third switch device, a control end of the third switch device serves as the control end of the first switch circuit, a first end of the third switch device serves as the first end of the first switch circuit, and a second end of the third switch device serves as the second end of the first switch circuit;
In one possible implementation, each switch device is a thin film transistor;
In a second aspect, an embodiment of the present disclosure further provides a display apparatus, including: the display substrate according to the first aspect.
In a third aspect, an embodiment of the present disclosure further provides a design method of the display substrate according to the first aspect, including:
In one possible implementation, the determining the channel width-to-length ratio of the each switch device in the data switching circuit corresponding to the each region includes:
The present disclosure will be described in detail below, and examples of embodiments of the present disclosure are illustrated in the accompanying drawings. The same or similar labels throughout represent the same or similar component or a component with the same or similar function. In addition, if any detailed description to any known technology is unnecessary to an illustrated feature of the present disclosure, such decryption will be omitted. The embodiments described below with reference to the accompanying drawings are used as examples. These embodiments are merely used to explain the present disclosure and shall not be interpreted as limitation to the present disclosure.
Those of skill in the art may understand that, unless as otherwise defined, all terms used herein (including technical terms and scientific terms) have the common meaning generally understood by those of ordinary skill in the art to which the present disclosure belongs. It should further be understood that those terms defined in a general dictionary should be understood as having the meanings consistent with the meanings in the context of the related art. Unless as specifically defined here, such terms will not be explained into any idealized or excessively meanings.
Those of skill in the art may understand that, unless as specifically stated, singular forms used herein, including “one”, “a”, “said” and “such”, may include plural forms as well. It should further be understood that the wording “include” used in the specification of the present disclosure refers existence of a feature, an integer, a step, an operation, an element and/or an assembly, without excluding the existence or addition of one or a plurality of other features, integers, steps, operations, elements, assemblies and/or a combination thereof. It should be understood that when we call an element “connected” or “coupled” to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element. In addition, “connection” or “coupling” used herein may include wireless connection or wireless coupling. The wording “and/or” used herein includes one or a plurality relevant listed items or a combination of any one or all of these listed items.
Technical solutions of the present disclosure as well as how the technical solutions of the present disclosure solve the above technical problem will be described in detail below through specific embodiments.
Embodiments of the present disclosure provide a display substrate. As shown in
As shown in
The data signal in the embodiments of the present disclosure is output by each switch device, when the switch device is turned off, an written grayscale is coupled and pulled down, so a part of the grayscale is lost, i.e. a voltage of the data signal is lowered. Because the specially shaped display substrate has an irregular shape, the regions vary in data payload, and the voltage losses of the data signal are different. In the embodiments of the present disclosure, the channel width-to-length ratio of each switch device in each data switching circuit is positively correlated with the design data payload of the region corresponding to the data switching circuit, so different switch devices may be matched according to different design data payloads of different regions. Therefore, a grayscale integrity is ensured, and technical support is provided for display of a customized specially shaped product.
In some embodiments, the display substrate 100 is a specially shaped substrate, and at least two regions in the specially shaped substrate include at least one of the followings: different shapes, different areas or different curvatures. Because the at least two regions in the specially shaped substrate are different in shape, area or curvature, the data payloads of the at least two regions are different, and different switch devices are matched according to different design data payloads of different regions, i.e. the width-to-length ratios W/L of the switch devices in different regions are matched, which may ensure that under the same grayscale, the pixel circuits have the same written grayscale.
In some embodiments, the design data payload of each region is positively correlated with a parasitic capacitance of the switch device; and the parasitic capacitance of the switch device is a result of a first result divided by a second result. The first result is a result of the voltage loss of the data signal output by the data signal line multiplied by a parasitic capacitance on the data signal line, and the second result is a result of a voltage difference between a high level and a low level of the data signal minus the voltage loss of the data signal.
The inventor of the present disclosure considers that, because there is the parasitic capacitance in the switch device itself, the parasitic capacitance has direct proportion to the width W of the switch device. For customized specially shaped products in medium and large sizes, a difference in payloads formed by the resistors R and the capacitors C of the data signal lines is relatively large. A longer data signal line leads to a larger payload formed by the resistor R and the capacitor C. In practical application, the lengths L of switch devices are fixed, and different switch devices are designed and matched based on changes of the widths W.
To take a maximum payload caused by the resistor R and the capacitor C of the data signal line as a basis, a driving ability and the width-to-length ratio W/L of the switch device are relatively large. In a region with a relatively small data payload, a grayscale loss ΔVdata may exist when the switch device is turned off to cause capacitor coupling. The grayscale loss ΔVdata is obtained according to the following formula (1):
ΔVdata=(ΔU×Cgs_tft)/(Cdata+Cgs_tft) formula (1).
Where: Cgs_tft is the parasitic capacitance of the switch device, and as shown in
Specifically, it can be seen from formula (1) that, if the data signal lines are different and the switch device is designed with the region with the maximum data payload as a basis, the grayscale loss ΔVdata of a region with the minimum data payload is relatively large, and finally uneven brightness will be caused.
Based on conversion of formula (1), the parasitic capacitance Cgs_tft of the switch device may be obtained, and the parasitic capacitance Cgs_tft is obtained according to the following formula (2):
Cgs_tft=(ΔVdata×Cdata)/(ΔU−ΔVdata) formula (2).
Because ΔU, ΔVdata and Cdata may all be obtained, the parasitic capacitance Cgs_tft may be obtained through calculation, and the channel width-to-length ratio of the switch device may be determined according to a preset positive correlation coefficient between the channel width-to-length ratio W/L of the switch device and the parasitic capacitance Cgs_tft of the switch device. In practical application, the preset positive correlation coefficient is related to a manufacturing process of the switch device, and can be determined according to the actual manufacturing process of the switch device.
Optionally, one region may include at least two data signal lines, one of the data signal lines is electrically connected to one column of the pixel circuits, one data switching circuit includes at least two switch devices, and each of the switch devices are equal in channel width-to-length ratio.
For example, the switch devices include the first switch device Mux_G1 and the second switch device Mux_G2, a first data signal line D_1 and a second data signal line D_2 in the region connected to the first switch device Mux_G1 and the second switch device Mux_G2 have little difference in length, data signals output by the first data signal line D_1 and the second data signal line D_2 may be the same or may be different, and the first switch device Mux_G1 and the second switch device Mux_G2 in the same region have little difference in width-to-length ratio.
In some embodiments, one region includes the first data signal line D_1, the second data signal line D_2, a first pixel circuit 20 and a second pixel circuit 30. A signal switching circuit 10 includes the first switch device Mux_G1 and the second switch device Mux_G2. The first switch device Mux_G1 is electrically connected to the first pixel circuit 20 through the first data signal line D_1. The second switch device Mux_G2 is electrically connected to the second pixel circuit 30 through the second data signal line D_2. The channel width-to-length ratios of the first switch device Mux_G1 and the second switch device Mux_G2 are positively correlated with the design data payload of the region corresponding to the pixel circuits.
Optionally, the design data payload of the region includes design data payloads of the data signal lines. The data signal lines include the first data signal line D_1 and the second data signal line D_2. The width-to-length ratio of the first switch device Mux_G1 is positively correlated to the design data payload of the first data signal line D_1, and the width-to-length ratio of the second switch device Mux_G2 is positively correlated to the design data payload of the second data signal line D_2. The design data payload of each data signal line is correlated to the length of the data signal line. A longer data signal line corresponds to a larger design data payload.
The inventor of the present disclosure considers that, for the specially shaped display substrate, in order to save data signal lines in an integrated circuit to reduce a cost, one data input line is subjected to frequency multiplication division into two data signal lines. By turning on and turning off two switch devices, different data signals are switched and matched, so normal writing of grayscales of two different pixel circuits may be ensured.
Based on the above analysis, in some embodiments, a control end of the first switch device Mux_G1 is electrically connected a first control signal line, a first end of the first switch device Mux_G1 is electrically connected to a data input line D_3, and a second end of the first switch device Mux_G1 is electrically connected to the first data signal line D_1. A control end of the second switch device Mux_G2 is electrically connected to a second control signal line, a first end of the second switch device Mux_G2 is electrically connected to the data input line D_3, and a second end of the second switch device Mux_G2 is electrically connected to the second data signal line D_2.
Specifically, data signals of the data input line D_3 are respectively controlled by the first switch device Mux_G1 and the second switch device Mux_G2. The data signals may be grayscale signals with the same color or different colors.
As an example, as shown in
In the maximum data payload region, the data signal line DM corresponds to the data input line D_3, the data signal line DM_1 and the data signal line DM_2 correspond to the first data signal line D_1 and the second data signal line D_2 respectively, and the switch devices T2_1 and T2_2 correspond to the first switch device Mux_G1 and the second switch device Mux_G2 respectively. A data payload formed by the resistors R and the capacitors C on the data signal line DM_1 and the data signal line DM_2 is maximum.
In a multi-segment data payload matching design, on the basis of magnitudes of the data payloads, the corresponding switch devices T1_1 and T1_2 and the width-to-length ratios W/L of the switch devices T2_1 and T2_2 are matched, so as to solve the problem of grayscale loss caused because the first switch device Mux_G1 and the second switch device Mux_G2 are coupled due to the parasitic capacitance.
As shown in
The inventor of the present disclosure has respectively tested data signals in a minimum data payload region and a maximum data payload region of a display substrate in the prior art as well as data signals in the minimum data payload region and the maximum data payload region of the display substrate 100 of the present disclosure.
In the prior art, in the minimum data payload region, to take a test result of the data signal of the data signal line DL_1 as an example, a target data signal is 8V. When the first switch device Mux_G1 is turned off, because of the existence of the data payload, a voltage of the target data signal is pulled down; with the increase of a parasitic capacitance C of the first switch device Mux_G1, data signals actually output by the data signal line DL_1 are: 7.76914, 7.54447, 7.52902, 7.49018, 7.48551, and 7.44577; and the grayscale loss is between 0.23V and 0.55V. In the maximum data payload region, to take a test result of the data signal of the data signal line DM_1 as an example, a target data signal is 8V. When the first switch device Mux_G1 is turned off, with the increase of the parasitic capacitance C of the first switch device Mux_G1, data signals actually output by the data signal line DL_1 are: 7.96259, 7.96122, 7.95653, 7.95252, 7.93368, and 7.9217; and the grayscale loss is between 0.04V and 0.08V. The difference in grayscale losses of the maximum data payload region and the minimum data payload region will cause poor evenness of brightness.
Through the test of the related art, when the width-to-length ratios W/L of the first switch devices Mux_G1 are the same in the minimum data payload region and the maximum data payload region. That is, the width-to-length ratios of the switch devices are not matched according to different regions, so the voltage of the data signal in the maximum data payload region is pulled down by a relatively small extent, but there is a problem that the voltage of the data signal in the minimum data payload region is pulled down by a relatively large extent.
Based on the embodiments of the present disclosure, after different switch devices are matched in different data payload regions, that is, the width-to-length ratio of the first switch device Mux_G1 is adjusted, data signal actually output by the data signal line DL_1 are: 7.93396, 7.84908, 7.83685, 7.81961, and 7.80465; and the grayscale loss may be reduced to 0.07V, so brightness difference caused by grayscale loss is successfully reduced and brightness evenness of products is further improved.
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the switch devices are all thin film transistors; the control ends of the switch devices are gates of the thin film transistors; if the first ends of the switch devices are drain electrodes of the thin film transistors, the second ends of the switch devices are source electrodes of the thin film transistors; or if the first ends of the switch devices are source electrodes of the thin film transistors, the second ends of the switch devices are drain electrodes of the thin film transistors.
Based on the pixel circuits shown in
A first stage T1 is a reset stage, the first ends and second ends of the second switch circuit 202 and the fifth switch circuit 302 are conducted, the first ends and second ends of the third switch circuit 203 and the sixth switch circuit 303 are conducted, first initialization signals received by the first ends of the second switch circuit 202 and the fifth switch circuit 302 are respectively output to the first node A and the third node C, and second initialization signals received by the first ends of the third switch circuit 203 and the sixth switch circuit 303 are respectively output to the third node C and the fourth node D.
Specifically, the fourth switch device G4 and the ninth switch device G9 are conducted, the fifth switch device G5 and the tenth switch device G10 are conducted, the fourth switch device G4 and the ninth switch device G9 respectively output the first initialization signals received by the first ends thereof and output by the first initialization signal lines Vref1 to the first node A and the third node C, and the fifth switch device G5 and the tenth switch device G10 respectively output the second initialization signals received by the first ends thereof and output by the second initialization signal lines Vref2 to the second node B and the fourth node D.
A second stage T2 is a compensation stage, the first ends and second ends of the second switch circuit 202 and the fifth switch circuit 302 maintain conducted, the first ends and second ends of third switch circuit 203 and the sixth switch circuit 303 are turned off, the first ends and second ends of the first driving circuit 204 and the second driving circuit 304 are conducted, and the third node C and the fourth node D are charged until a voltage difference between the first node A and the third node C reach a threshold voltage of the first driving circuit 204 and a voltage difference between the second node B and the fourth node D reach a threshold voltage of the second driving circuit 304.
Specifically, the fourth switch device G4 and the ninth switch device G9 maintain conducted, the fifth switch device G5 and the tenth switch device G10 are turned off, the sixth switch device G6 and the eleventh switch device G11 are conducted, and the second node B and the fourth node D are charged until a voltage difference between the first node A and the second node B reach a threshold voltage of the sixth switch device G6 and a voltage difference between the third node C and the fourth node D reach a threshold voltage of the eleventh switch device G11.
A third stage T3 is a data writing stage, the first ends and second ends of the first switch circuit 201 and the fourth switch device 301 are conducted, the first ends and second ends of the second switch circuit 202 and the fifth switch circuit 302 are turned off, the first ends and second ends of the first light emitting control circuit 205 and the second light emitting control circuit 305 are turned off, the first switch device Mux_G1 is controlled to be conducted and the second switch device Mux_G2 is controlled to be turned off, the first data signal is output to the first node A, the second switch device Mux_G2 is controlled to be conducted and the first switch device Mux_G1 is controlled to be turned off, and the second data signal is output to the second node B.
Specifically, the third switch device G3 and the eighth switch device G8 are conducted, the fourth switch device G4 and the ninth switch device G9 are cut off, and the seventh switch device G7 and the twelfth switch device G12 are cut off, the first switch device Mux_G1 is controlled to be conducted and the second switch device Mux_G2 is controlled to be turned off, the first data signal is output to the first node A, the second switch device Mux_G2 is controlled to be conducted and the first switch device Mux_G1 is controlled to be turned off, and the second data signal is output to the second node B.
Specifically, voltages of the first data signal and the second data signal are different.
A fourth stage T4 is a light emitting stage, the first ends and second ends of the first switch circuit 201 and the fourth switch device 301 are turned off, the first switch device Mux_G1 and the second switch device Mux_G2 are turned off, and the first ends and second ends of the first light emitting control circuit 205 and the second light emitting control circuit 305 are conducted, so as to drive the first light emitting device and the second light emitting device to emit light.
Specifically, the third switch device G3 and the eighth switch device G8 are cut off, the first switch device Mux_G1 and the second switch device Mux_G2 are turned off, and the seventh switch device G7 and the twelfth switch device G12 are conducted, so as to drive the first light emitting device and the second light emitting device to emit light.
Based on the same inventive concept, embodiments of the present disclosure further provide a display apparatus, including the display substrate 100 provided by the embodiments of the present disclosure.
Based on the same inventive concept, embodiments of the present disclosure further provide a design method of a display substrate, applied to the display substrate 100 provided by the embodiments of the present disclosure, and including: determining, according to a design data payload of each region in pixel circuits, a channel width-to-length ratio of each of switch devices in a data switching circuit corresponding to the each region.
Specifically, as shown in
S501, a parasitic capacitance of each of the switch devices is determined, where the parasitic capacitance of the each switch device is a result of a first result divided by a second result, the first result is a result of a voltage loss of a data signal output by the data signal line multiplied by a parasitic capacitance on the data signal line, the second result is a result of a voltage difference between a high level and a low level of the data signal minus the voltage loss of the data signal, and the switch devices include a first switch device Mux_G1 and a second switch device Mux_G2.
Optionally, according to formula (2) of the embodiments of the present disclosure, the parasitic capacitance Cgs_tft of the switch device may be obtained. Because ΔU, ΔVD and CD may all be obtained, the parasitic capacitance Cgs_tft may be obtained through calculation, and the channel width-to-length ratio of the switch device may be determined according to a preset positive correlation coefficient between the channel width-to-length ratio W/L of the switch device and the parasitic capacitance Cgs_tft of the switch device.
S502, the channel width-to-length ratio of the switch device is determined according to a positive correlation coefficient between the channel width-to-length ratio of the switch device and the parasitic capacitance of the switch device.
In practical application, the preset positive correlation coefficient is related to a manufacturing process of the switch device, and can be determined according to the actual manufacturing process of the switch device.
Those of skill in the art may understand that, steps, measures, and solutions in various operations, method, and procedures discussed in the present disclosure may be alternated, changed, combined or deleted. Further, other steps, measures, and solutions in the operations, method, and procedures discussed in the present disclosure may be alternated, changed, re-ranked, decomposed, combined or deleted. Further, steps, measures, and solutions in the operations, method, and procedures in the prior art disclosed in the present disclosure may also be alternated, changed, re-ranked, decomposed, combined or deleted.
Terms “first” and “second” are merely used for describe, and cannot be understood as implying or indicating relevant significance or implying the quantity of any indicated technical features. Therefore, a feature limited by “first” or “second” may explicitly or implicitly include one or more features. In the description of the present disclosure, unless other expressed, the meaning of “a plurality of” is two or more than two.
It should be understood that, although all steps in the flow chart in the accompanying drawings are displayed in a sequence indicated by arrows, such steps are not necessarily executed in the sequence indicated by arrows. Unless expressly stated herein, execution of these steps are not limited by any restrict sequence, and may be executed in other sequence. Further, at least a part of steps in the flow chart in the accompanying drawings may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily executed at the same moment, but may be executed at different moments. They may not necessarily be executed in sequence, but may be alternatively executed or executed in turns together with any other steps or at least a part of sub-steps or stages of other steps.
The above descriptions are merely a part of implementations of the present disclosure. It should be pointed out that, to those of ordinary skill in the art, several modifications and polishings may further be made without departing from the principles of the present disclosure, and such modifications and polishings should be deemed within the scope of protection of the present disclosure as well.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010538367.4 | Jun 2020 | CN | national |
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|---|---|---|---|
| PCT/CN2021/098090 | 6/3/2021 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/249273 | 12/16/2021 | WO | A |
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