CN111417233B - Lamp and method for eliminating low-gray jitter of LED display - Google Patents
Lamp and method for eliminating low-gray jitter of LED display Download PDFInfo
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- CN111417233B CN111417233B CN201911130998.6A CN201911130998A CN111417233B CN 111417233 B CN111417233 B CN 111417233B CN 201911130998 A CN201911130998 A CN 201911130998A CN 111417233 B CN111417233 B CN 111417233B
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Abstract
The invention relates to a lamp and a method for eliminating LED display low-gray jitter, wherein an LED lamp unit comprises a power module, a decoding module and a display module, the decoding module receives data sent by a controller end and generates a PWM control signal, the PWM control signal outputs a duty ratio, and the duty ratio is switched back and forth between two PWM outputs of previous frame data and current data so as to smooth the transition between two levels of gray scales, thereby eliminating the problem of LED display low-gray jitter.
Description
Technical Field
The invention relates to the technical field of LED lighting display, in particular to a lamp and a method for eliminating low-gray jitter of LED display.
Background
The existing LED has the advantages of long service life, energy conservation, environmental protection, pure and thick color and the like, and is widely applied to the fields of stage lighting, urban landscape brightening and the like. Wherein, the project lamps in the field of stage lamps and landscape brightening all need to adopt high-power LEDs so as to meet the requirement of high brightness of the lamps. The brightness of the lamp is increased, and the brightness difference between two adjacent gray scales is correspondingly increased. Particularly in the low gray scale, even if the brightness of the gamma correction 65536 level gray scale lamp is small, the same brightness change is more easily captured by human eyes, which causes the human eyes to feel that the lamp light is slightly jittered when the low gray scale lamp is gradually displayed, and the display effect is affected.
The current solutions are two of the following:
1. processing at the controller end, and implementing smooth transition of two gray scale changes by inserting more data frames between two display data frames, but this may bring new problems, and the display end cannot respond to the change of data in real time due to the insertion of the data frames, and produces a smear phenomenon, as shown in fig. 4, it is a schematic diagram of a general output mode of data frame update PWM;
2. and processing is carried out at the lamp end, and a special 16-bit gray scale decoding chip or a high-performance single chip microcomputer is selected to insert more gray scale steps between two levels of gray scales. But this results in a doubling of the controller transmitted data and, under frame rate constraints, a reduction in the number of payloads.
In addition, a 16-bit decoding chip or a single chip microcomputer capable of realizing 16-bit PWM output is expensive, so that the product cost is increased and the market competitiveness is lacked. And the problems of display jitter and smear are difficult to solve.
Therefore, there is a need for a lamp and method that eliminates low gray jitter of the LED display.
Disclosure of Invention
The invention aims to solve the technical problem of eliminating the problem of LED low-gray section display jitter under the conditions of not increasing the lamp cost and not causing the problem of smear by implementing the lamp and the method for solving the problem of LED low-gray section jitter at the end of an LED lamp.
In order to solve the technical problem, the invention provides a lamp and a method for eliminating low gray jitter of LED display, comprising an LED lamp unit, wherein the LED lamp unit comprises a power supply module, a decoding module and a display module, the power supply module is used for supplying power to the decoding module and the display module, the decoding module comprises a decoding chip U1, a capacitor C1, resistors R1, R2 and R3, the decoding chip U1 comprises a data frame interval measuring unit, a data frame decoding unit, a PWM refreshing frequency configuration unit, a PWM duty ratio configuration unit and a PWM output switching unit, the decoding module receives data sent by a controller end and generates a PWM control signal, the PWM control signal outputs a duty ratio, and the duty ratio is switched back and forth between two PWM outputs of previous frame data and current data to smooth the transition between two levels of gray scales;
the method for eliminating the low gray jitter of the LED display comprises the following steps:
a. electrifying the LED lamp unit, and electrically connecting the power supply module, the decoding module and the display module together;
b. the decoding chip U1 forms an AB differential data port and is connected with a controller data bus through resistors R2 and R3;
c. the controller end sends display data to a data port of the decoding chip U1 through a data line, and the data frame decoding unit converts the display data into PWM duty ratio data and sends the PWM duty ratio data to the PWM duty ratio configuration unit;
d. the decoding module generates the PWM output when receiving the gray scale change of the display data sent by the controller;
e. a plurality of display driving ports OUT of the decoding chip U1 are provided, and PWM waveforms are respectively output to control the display module;
f. meanwhile, the data frame interval detection unit feeds back the measured data frame interval time to the PWM refreshing frequency configuration unit so as to ensure that the PWM can output enough times within the data frame interval time;
g. then the PWM refreshing frequency configuration unit and the PWM duty ratio configuration unit feed back data to the PWM output switching unit;
h. finally, the PWM output switching unit distributes the switching rule of the PWM duty ratios of the two data frames according to the interval time of the data frames and the PWM refreshing frequency so as to realize the smooth change of the LED display;
i. repeating the steps a to h until the LED display low-gray jitter is eliminated.
The display module is composed of LED lamp beads and can be directly connected with a plurality of OUT output ports of the decoding module.
The further scheme is that the PWM control signal is used for controlling the display module to realize different display effects according to the display data requirement sent by the controller.
Further, the PWM output is switched between the previous frame data and the current data, and the switching time is less than or equal to the interval of two data frames.
The further scheme is that the output of the PWM control signal is switched step by step, and the PWM refreshing frequency configuration module ensures that the implementation is finished in a data frame interval, namely the whole processing process is finished before the display of the next frame.
Further, the decoding chip U1 can add a driving module to drive the LED to display, and the driving module is connected to the OUT output port of the decoding module and controlled by the PWM waveform output from the OUT port of the decoding module.
Further, the number of the display driving ports of the decoding chip U1 is multiple, and the number of the display driving ports connected to the display modules is adjusted as needed.
Further, one end of the resistor R1 is used as a power input end of the decoding module, the other end of the resistor R1 and one end of the capacitor C1 are connected to the power port VDD of the decoding chip U1, and the other end of the capacitor C1 and the GND of the decoding chip U1 are connected to ground.
The scheme is that one end of the resistor R2 is connected with a data input port DIN of the decoding chip, and the other end of the resistor R2 is used as a data input port of the decoding module and is connected with the controller in a data mode.
Compared with the prior art, the invention has the beneficial effects that: the LED lamp unit comprises a power supply module, a decoding module and a display module, wherein the decoding module receives data sent by a controller end and generates a PWM control signal, the PWM control signal outputs a duty ratio, and the duty ratio is switched back and forth between two PWM outputs of previous frame data and current data so as to smooth the transition between two levels of gray scales, thereby eliminating the problem of low gray jitter of LED display, reducing the cost of high-power products, improving the display quality and improving the reliability, and the LED lamp unit has the following main beneficial effects:
1. the problem of jitter of the high-power LED during low-ash gradual change is solved on the premise of not increasing the cost;
2. the problem of smear caused by a common data frame interpolation method is solved;
3. the solution is implemented on the LED lamp, the controller does not need to be specially processed, and the LED lamp is compatible with a general controller.
Drawings
Fig. 1 is a schematic structural diagram of an LED lamp unit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a decoding module and a display module according to an embodiment of the present invention;
FIG. 3 is a diagram of a decoding chip U1 according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating a general output manner of data frame update PWM;
fig. 5 is a schematic diagram illustrating an output manner of implementing PWM for updating data frames according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1 to 5, in an embodiment of the present invention, a lamp and a method for eliminating low gray jitter of LED display include an LED lamp unit, where the LED lamp unit includes a power module, a decoding module and a display module, the power module is used to supply power to the decoding module and the display module, the decoding module includes a decoding chip U1, a capacitor C1 and resistors R1, R2 and R3, the decoding chip U1 includes a data frame interval measuring unit, a data frame decoding unit, a PWM refresh frequency configuration unit, a PWM duty cycle configuration unit and a PWM output switching unit, the decoding module receives data sent by a controller terminal and generates a PWM control signal, and the PWM control signal outputs a duty cycle, which is switched back and forth between two PWM outputs of previous frame data and current data to smooth transition between two levels of gray scales;
the lamp and the method for eliminating the low gray jitter of the LED display comprise the following steps:
a. the LED lamp unit is electrified, and the power supply module, the decoding module and the display module are electrically connected together;
b. the decoding chip U1 forms an AB differential data port and is connected with a controller data bus through resistors R2 and R3;
c. the controller end sends display data to a data port of a decoding chip U1 through a data line, and a data frame decoding unit converts the display data into PWM duty ratio data and sends the PWM duty ratio data to a PWM duty ratio configuration unit;
d. the decoding module generates PWM output when receiving the gray scale change of the display data sent by the controller;
e. a plurality of display driving ports OUT of the decoding chip U1 are provided, and PWM waveforms are respectively output to control the display module;
f. meanwhile, the data frame interval detection unit feeds back the measured data frame interval time to the PWM refreshing frequency configuration unit so as to ensure that the PWM can output enough times within the data frame interval time;
g. then the PWM refreshing frequency configuration unit and the PWM duty ratio configuration unit feed back data to the PWM output switching unit;
h. finally, the PWM output switching unit distributes the switching rule of the PWM duty ratios of the two data frames according to the interval time of the data frames and the PWM refreshing frequency so as to realize the smooth change of the LED display;
i. repeating the steps a to h until the LED display low-gray jitter is eliminated.
Furthermore, the display module is composed of LED lamp beads and can be directly connected with a plurality of OUT output ports of the decoding module.
Further, the PWM control signal is used to control the display module to achieve different display effects according to the display data requirements sent by the controller.
Further, the PWM output switches between the previous frame data and the current data for a switching time less than or equal to the interval of the two data frames.
Further, the output of the PWM control signal is switched step by step, and the PWM refresh frequency configuration module ensures that the processing is completed within one data frame interval, i.e. the whole processing is completed before the next frame is displayed.
Furthermore, the decoding chip U1 can add a driving module to drive the LED display, and the driving module is connected to the OUT output port of the decoding module and controlled by the PWM waveform output from the OUT port of the decoding module.
Furthermore, the number of the display driving ports of the decoding chip U1 is multiple, and the number of the display driving ports connected to the display modules is adjusted as required.
Furthermore, one end of the resistor R1 is used as a power input end of the decoding module, the other end and one end of the capacitor C1 are connected to the power port VDD of the decoding chip U1, and the other end of the capacitor C1 and GND of the decoding chip U1 are connected to ground.
Further, one end of the resistor R2 is connected to the data input port DIN of the decoding chip, and the other end is used as the data input port of the decoding module and is connected to the controller data.
As shown in fig. 1, the whole LED lamp unit is composed of a power supply module, a decoding module, and a display module. The power module is used for supplying power to the decoding module and the display module, the decoding module receives data sent by the controller end and generates a PWM control signal, and the PWM control signal is used for controlling the display module to achieve different display effects according to the display data requirement sent by the controller. When the decoding module receives the gray scale change of the display data sent by the controller, the PWM output is not directly output according to the duty ratio of new data in a normal mode, but is switched back and forth between the two PWM outputs of the previous frame data and the current data according to a certain rule so as to smooth the transition between the two levels of gray scales. This corresponds to achieving more PWM gray scale levels without increasing the number of bytes of display data. Meanwhile, the switching time is less than or equal to the interval of two data frames, so that the phenomenon of smear cannot be generated.
As shown in fig. 2, the LED lamp decoding module and the display module include:
the decoding module comprises a decoding chip U1, a capacitor C1, resistors R1, R2 and R3, wherein one end of the resistor R1 is used as a power input end of the decoding module, the other end of the resistor R1 and one end of the capacitor C1 are connected to a power port VDD of the decoding chip U1 in a sharing mode, and the other end of the capacitor C1 and GND of the decoding chip U1 are connected to the ground in a sharing mode. One end of the resistor R2 is connected with the data input port DIN of the decoding chip, and the other end of the resistor R2 is used as the data input port of the decoding module and is connected with the data of the controller. The decoder chip may also be configured as an AB differential data port connected to the controller data bus through resistors R2, R3, as shown in the dashed box. The display driving ports OUT 1-3 of the decoding chip U1 output PWM waveforms for controlling the display module, and the number of the driving ports is not limited in practical situations and is determined according to requirements. The display module is composed of LED lamp beads and can be directly connected with an OUT output port of the decoding module. As shown by the dashed line block, the decoding chip U1 may also add a driving module to drive the LED display, where the driving module is connected to the OUT output port of the decoding module and controlled by the PWM waveform output from the OUT port of the decoding module.
As shown in fig. 3, the decoding chip U1 includes:
the device comprises a data frame interval measuring unit, a data frame decoding unit, a PWM refreshing frequency configuration unit, a PWM duty ratio configuration unit and a PWM output switching unit.
The control end sends display data to a data port of the decoding chip U1 through a data line, and the data frame decoding unit converts the display data into PWM duty ratio data and sends the PWM duty ratio data to the PWM duty ratio configuration unit. Meanwhile, the data frame interval detection unit feeds back the measured data frame interval time to the PWM refreshing frequency configuration unit so as to ensure that the PWM can output enough times within the data frame interval time. And finally, the PWM output switching unit distributes the switching rule of the PWM duty ratios of the two data frames according to the interval time of the data frames and the PWM refreshing frequency so as to realize the smooth change of the LED display.
As shown in fig. 4, a general data frame update PWM output mode is shown, and after a data frame is updated, the PWM output is immediately updated from the previous frame output waveform a to the output B corresponding to the current data frame.
As shown in fig. 5, in the output mode for implementing data frame update PWM according to the present invention, in the whole data frame interval, the duty ratio of the output waveform a of the previous frame gradually decreases and disappears, and the duty ratio of the PWM output waveform B corresponding to the current data frame gradually increases to the last 100% for output.
The process of gradually switching the PWM output is ensured to be completed in a data frame interval through the PWM refreshing frequency configuration module, namely the whole processing process is completed before the next frame is displayed, so that the problem of smear caused by a frame inserting mode of a controller is solved. Meanwhile, the byte number of display data supported by the decoding chip is not increased, but the output of more PWM gray scale levels is realized, and the problem of display jitter of the low-gray-scale LED is solved under the condition of not increasing the cost.
In summary, the technical solution of the present invention mainly includes the following points:
1. the PWM output duty ratio of the decoding chip U1 adopts a control method of gradual switching;
the number and time of the PWM output in a step-by-step switching mode can be configured;
3. the data frame interval detection, PWM refreshing frequency control and PWM switching output are carried out in a whole control method.
Compared with the prior art, the invention has the beneficial effects that: the LED lamp unit comprises a power supply module, a decoding module and a display module, wherein the decoding module receives data sent by a controller end and generates a PWM control signal, the PWM control signal outputs a duty ratio, and the duty ratio is switched back and forth between two PWM outputs of previous frame data and current data so as to smooth the transition between two levels of gray scales, thereby eliminating the problem of low gray jitter of LED display, reducing the cost of high-power products, improving the display quality and improving the reliability, and the LED lamp unit has the following main beneficial effects:
1. the problem of jitter of the high-power LED during low-ash gradual change is solved on the premise of not increasing the cost;
2. the problem of smear caused by a common data frame interpolation method is solved;
3. the solution is implemented on the LED lamp, the controller does not need to be specially processed, and the LED lamp is compatible with a general controller.
The above description is only a preferred embodiment of the present patent, and not intended to limit the scope of the present patent, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the specification and the drawings, and which are directly or indirectly applied to other related technical fields, belong to the scope of the present patent protection.
Claims (9)
1. A method for eliminating LED display low-gray jitter is characterized in that the method is applied to an LED lamp unit, the LED lamp unit consists of a power supply module, a decoding module and a display module, the power supply module is used for supplying power to the decoding module and the display module, the decoding module comprises a decoding chip U1, a capacitor C1, resistors R1, R2 and R3, the decoding chip U1 comprises a data frame interval measuring unit, a data frame decoding unit, a PWM refreshing frequency configuration unit, a PWM duty ratio configuration unit and a PWM output switching unit, the decoding module receives data sent by a controller end and generates PWM control signals, the PWM control signals output duty ratios, and the duty ratios are switched back and forth between two PWM outputs of previous frame data and current data to smooth transition between two levels of gray scales;
the method for eliminating the low gray jitter of the LED display comprises the following steps:
a. electrifying the LED lamp unit, and connecting the power supply module, the decoding module and the display module together;
b. the decoding chip U1 comprises A, B two differential data ports which are connected with a controller data bus through resistors R2 and R3;
c. the controller end sends display data to a data port of the decoding chip U1 through a data line, and the data frame decoding unit converts the display data into PWM duty ratio data and sends the PWM duty ratio data to the PWM duty ratio configuration unit;
d. the decoding module generates the PWM output when receiving the gray scale change of the display data sent by the controller;
e. a plurality of display driving ports OUT of the decoding chip U1 are provided, and PWM waveforms are respectively output to control the display module;
f. meanwhile, the data frame interval detection unit feeds back the measured data frame interval time to the PWM refreshing frequency configuration unit so as to ensure that the PWM can output enough times within the data frame interval time;
g. then the PWM refreshing frequency configuration unit and the PWM duty ratio configuration unit feed back data to the PWM output switching unit;
h. finally, the PWM output switching unit distributes the switching rule of the PWM duty ratios of the two data frames according to the interval time of the data frames and the PWM refreshing frequency so as to realize the smooth change of the LED display;
i. repeating the steps a to h until the LED display low-gray jitter is eliminated.
2. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the display module is composed of LED lamp beads and can be directly connected with a plurality of OUT output ports of the decoding module.
3. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the PWM control signal is used for controlling the display module to realize different display effects according to the display data requirement sent by the controller.
4. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the PWM output switches between a previous frame of data and a current frame of data for a switching time less than or equal to the interval of the two frames of data.
5. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the output of the PWM control signal is switched step by step, and the PWM refreshing frequency configuration module ensures that the implementation is finished in a data frame interval, namely the whole processing process is finished before the display of the next frame.
6. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the decoding chip U1 can be added with a driving module to drive the LED to display, and the driving module is connected with the OUT output port of the decoding module and is controlled by the PWM waveform output by the OUT port of the decoding module.
7. The method of eliminating low gray jitter of an LED display of claim 1, wherein: the number of the display driving ports of the decoding chip U1 is multiple, and the number of the display driving ports connected with the display modules is adjusted according to the need.
8. The method of eliminating low gray jitter of an LED display of claim 1, wherein: one end of the resistor R1 is used as a power input end of the decoding module, the other end of the resistor R1 and one end of the capacitor C1 are connected to a power port VDD of the decoding chip U1, and the other end of the capacitor C1 and GND of the decoding chip U1 are connected to the ground.
9. The method of eliminating low gray jitter of an LED display of claim 1, wherein: one end of the resistor R2 is connected with the data input port DIN of the decoding chip, and the other end of the resistor R2 is used as the data input port of the decoding module and is connected with the data of the controller.
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