Self-powered cholesteric phase display screen display driving system and control method thereof

Abstract

The invention discloses a self-powered cholesteric phase display screen display driving system and a control method thereof, and belongs to the technical field of display. The system comprises a low-light energy acquisition module, an energy management module, a control module and a display driving module. The control module controls the turn-off and turn-on of the voltage output function of the energy management module by outputting a sleep / wake-up signal, so that the system is charged by using ambient light during sleep, and image refreshing is quickly completed and the system enters sleep again during wake-up. By setting a balance point of wake-up time and energy consumption, it is ensured that refreshing energy consumption is lower than charging energy, so that energy self-balance and continuous work of the system in a luminous environment are achieved, and external charging is not needed. The problems that an existing cholesteric phase display needs frequent external charging during continuous work and a traditional light energy power supply scheme is low in efficiency in the low-light environment are mainly solved, self-powered continuous operation of the cholesteric phase display in the indoor and outdoor low-light environment is achieved, and use convenience is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a self-powered cholesteric display screen display driving system and a control method thereof. BACKGROUND

[0002] Cholesteric liquid crystal display (Ch-LCD) can maintain image display without continuous power supply based on its bistable characteristics, which makes it highly concerned in the field of low-power display. Its bistable performance is focal conic state and planar state, and the conversion between the two states can be realized by applying voltage, thereby controlling the reflection or transmission behavior of liquid crystal to light, realizing display function. Since it only needs to consume power when refreshing the image, and the power consumption is very low when displaying statically, Ch-LCD is very suitable for application scenarios such as electronic price tags and information signs.

[0003] Although Ch-LCD itself has the advantage of low power consumption, it still faces energy supply problems in actual application. Especially in outdoor, supermarket, bus station and other continuous working and charging inconvenient scenes, the energy of system energy storage elements (such as batteries or capacitors) will be gradually consumed due to periodic refreshing, and must rely on external charging to maintain operation, which seriously affects user experience.

[0004] To break through this limitation, a solution of matching a solar panel on the back of the cholesteric liquid crystal display panel appears in the prior art. This solution uses the part of ambient light transmitted by the display panel, which is absorbed by the solar panel and converted into electrical energy, stored in the energy storage device, used to drive picture update, thereby realizing the theoretical self-powered function. However, this solution has obvious limitations: in indoor environment, ambient light mainly comes from light or scattered sunlight, and the light intensity is significantly lower than that in outdoor environment. The photoelectric conversion efficiency of traditional solar panels under such weak light conditions decreases sharply, and cannot provide enough electrical energy, resulting in that the system cannot work normally. In addition, cholesteric liquid crystal display only needs high voltage during refreshing, while the output power of the whole solar panel is high under strong light, and there is a lack of efficient power matching and dynamic management mechanism between them, which still needs to rely on additional electrical energy conversion and management devices for adaptation, increasing the system complexity and cost.

[0005] Therefore, the prior art has not truly realized the energy self-provision and long-term stable work of Ch-LCD display system in real light environment, especially in low-light environment, and there is an urgent need for a low-power system architecture and control method that can efficiently collect and manage low-light energy and is highly adapted to the driving characteristics of Ch-LCD. SUMMARY

[0006] To solve the technical problems in the background art, the application provides a self-powered cholesteric display screen display driving system and a control method thereof.

[0007] The self-powered cholesteric display screen display driving system provided by the application comprises: The micro-light energy collection module is configured to receive ambient light and generate collected electric energy. The energy management module is configured to receive and manage the collected electric energy, charge manage the energy storage element inside the energy management module, provide charge-discharge loop protection, and convert and stabilize the output voltage of the energy storage element through step-up and step-down conversion, so as to finally provide a stable system working voltage from the output end of the energy management module. The control module is configured to output a sleep control signal or a wake-up control signal to control the opening and closing of the voltage output function of the energy management module. The display driving module is configured to drive the cholesteric display screen to refresh an image when the system working voltage is obtained. The control module is configured to output a sleep control signal when the system is in a sleep mode, so that the energy management module stops outputting the system working voltage, and at this time, the micro-light energy collection module continuously charges the energy storage element. The control module is also configured to switch to a working mode and output a wake-up control signal when a preset wake-up time is reached, so that the energy management module outputs the system working voltage, and the display driving module is controlled to perform an image refresh operation, and then the sleep control signal is outputted again to return the system to the sleep mode.

[0008] Preferably, the micro-light energy collection module is a light energy film made of carbon-based material and attached to the back of the cholesteric display screen.

[0009] Preferably, the energy management module comprises an energy collection chip, an energy storage element, a battery protection circuit and a step-up and step-down conversion circuit connected in sequence. The input end of the energy collection chip is connected to the micro-light energy collection module, and is configured to maximize the collection of the collected electric energy. The energy storage element is connected to the output end of the energy collection chip, and is configured to store electric energy. The input end of the step-up and step-down conversion circuit is connected to the energy storage element through the battery protection circuit, the output end of the step-up and step-down conversion circuit is configured to provide the system working voltage, and the enable end of the step-up and step-down conversion circuit is connected to the control signal output end of the control module.

[0010] Preferably, the energy storage element is a lithium battery or a super capacitor.

[0011] Preferably, the control module comprises a low-power microcontroller (MCU), and the input / output port of the MCU constitutes the control signal output end.

[0012] Preferably, the system operating voltage is a direct current voltage of 4.5-21 V.

[0013] The application provides a control method of a self-powered cholesteric display screen display driving system, which comprises the following steps: In the sleep mode, the control module controls the energy management module to stop supplying power to the display driving module and acquires the charging energy of the micro-light energy collection module under ambient light; The control module processes the charging energy and the preset image refresh energy consumption, and when the system reaches the preset wake-up time or the power of the energy storage element is higher than the preset refresh threshold, the control module outputs a wake-up control signal to the energy management module to obtain the system operating voltage to start the display driving module; The control module controls the display driving module to perform an image refresh operation to obtain an image refresh completion result, and then outputs a sleep control signal again to return the system to the sleep mode.

[0014] Preferably, the preset wake-up time and / or the preset refresh threshold are set by comparing the charging energy of the micro-light energy collection module in a unit time and the energy consumption of a single image refresh, to ensure that the charging energy of the system in the preset wake-up time is greater than the energy consumption of a single image refresh.

[0015] Preferably, the specific value E of the charging energy in a unit time is calculated as follows: ; Wherein, P is the power generation power of the micro-light energy collection module under the current ambient illuminance, and T is the system sleep time.

[0016] In the application, the self-powered cholesteric display screen display driving system and the control method thereof are introduced, the carbon-based micro-light energy collection film and the high-integration energy management are introduced, the efficient capture and conversion of ambient light energy are effectively realized, and the electric energy can be continuously accumulated even under indoor weak light conditions; in combination with the precise sleep-wake mechanism of the low-power control module, the system is in an ultra-low power standby state most of the time, and only starts instantaneously to complete image refresh and quickly returns to sleep when necessary, so that the overall energy consumption is significantly reduced. The system realizes the energy self-supply of cholesteric display under various real light scenes, greatly prolongs the continuous working time of the equipment, reduces the dependence on external charging, improves the deployment flexibility and use convenience, and reduces the system maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The application provides a system architecture schematic diagram of a self-powered cholesteric display screen display driving system; Figure 2 The application provides a structure schematic diagram of an embodiment of a self-powered cholesteric display screen display driving system; Figure 3 This is a schematic diagram of the Boost circuit structure of a self-powered cholesteric phase display screen driving system proposed in this invention; Figure 4 This is a schematic diagram of the working process of a control method for a self-powered cholesteric phase display screen driving system proposed in this invention; Figure 5 Voltage variation curve of existing cholesteric phase display screen after 24 hours of operation; Figure 6 The voltage change curve of the self-powered cholesteric phase display screen after 24 hours of operation is shown in the control method of the self-powered cholesteric phase display screen driving system proposed in this invention. Detailed Implementation

[0018] Reference Figures 1-4 The present invention proposes a self-powered cholesteric phase display screen driving system, comprising: The low-light energy harvesting module is used to receive ambient light and generate harvested electrical energy; The energy management module is used to receive and manage the collected electrical energy, manage the charging of the energy storage components inside the energy management module, provide charging and discharging circuit protection, and convert and regulate the output voltage of the energy storage components, ultimately providing a stable system operating voltage from the output of the energy management module. The control module is configured to output a sleep control signal or a wake-up control signal to control the on and off of the voltage output function of the energy management module; The display driver module is used to drive the cholesteric phase display screen to refresh the image when the system operating voltage is obtained; The control module is configured to output a sleep control signal when the system is in sleep mode, causing the energy management module to stop outputting the system operating voltage. At this time, the low-light energy acquisition module continues to charge the energy storage element. The control module is also configured to switch to the working mode and output a wake-up control signal when the preset wake-up time is reached, causing the energy management module to output the system operating voltage and control the display driver module to perform an image refresh operation. After that, it outputs the sleep control signal again to make the system return to sleep mode.

[0019] Specifically, such as Figure 1 As shown, this is the driving architecture of the system. The system consists of a low-light energy acquisition module, an energy management module, a control module, and a display driver module, which output a stable voltage to power the system.

[0020] In this embodiment, the low-light energy acquisition module is a light energy thin film made of carbon-based material, which is attached to the back of the cholesteric phase display screen.

[0021] Specifically, in application, the area of ​​the light-emitting thin film is designed according to the product requirements and size of the cholesteric display screen, such as... Figure 2As shown, the light energy film is pasted behind the cholesteric display screen, and the positive and negative electrode lines are led out and connected to the input end of the energy management module, and the output voltage is used to charge the energy storage element of the energy management module, and then the output voltage is output to the cholesteric display system mainboard through the battery protection circuit and the boost-buck conversion circuit for power supply.

[0022] In the embodiment, the energy management module comprises an energy collection chip, an energy storage element, a battery protection circuit and a boost-buck conversion circuit connected in sequence. The input end of the energy collection chip is connected with the micro-light energy collection module, and is used for maximizing the collection of the collected electric energy. The energy storage element is connected with the output end of the energy collection chip, and is used for storing electric energy. The input end of the boost-buck conversion circuit is connected with the energy storage element through the battery protection circuit, the output end of the boost-buck conversion circuit is used for providing system working voltage, and the enable end of the boost-buck conversion circuit is connected with the control signal output end of the control module.

[0023] Specifically, the energy storage element is a lithium battery or a super capacitor.

[0024] Specifically, as shown in the figure, Figure 3 The boost-buck conversion circuit adopts a boost circuit, and the on-off of the switch tube is controlled through the boost circuit to convert the input voltage into system working voltage. The conversion formula is ; wherein, The input battery voltage; D is the PWM duty cycle; The system working voltage of the circuit output to the system. The function of the circuit is mainly used to realize the boost of the stored electric energy and convert it into the required load use voltage. In the circuit, V1 is the battery or super capacitor, L1 is the boost inductance, Q1 is the NMOS tube, and the output voltage is controlled by the PWM regulation D duty cycle. Among them, the diode D1 is used to realize the boost rectification function, the capacitor C1 has the function of filtering, and R1 is the analog load.

[0025] In the embodiment, the control module comprises a low-power microcontroller MCU, and the input / output port of the MCU constitutes the control signal output end.

[0026] Specifically, the system working voltage is 4.5V-21V direct current voltage.

[0027] In the embodiment, the cholesteric LCD power supply circuit is powered in the low-power mode, and the consumption of electric energy needs to be balanced. The circuit scheme is designed to supplement energy, so that the consumption of the picture brushing is less than the charging energy, and no external charging is needed in the working process.

[0028] As shown in the figure, Figure 1As shown, when the control module starts the low-power consumption control mode, the whole system enters the sleep mode and starts timing work. In the sleep mode, the micro-light energy collection module continuously charges the energy storage element of the energy management module to accumulate electric energy. When the set timing sleep time ends and the picture brushing is started, the control module wakes up from the sleep and outputs a high-level control power enable signal to wake up the boost circuit, outputs a 4.5V-21V system working voltage to the system mainboard of the cholesteric display screen for power supply, and realizes the picture brushing Figure 1 When the picture brushing is finished, the control module outputs a low-level control enable to turn off the boost circuit. At this time, the cholesteric display screen continues to enter the sleep mode and circulates repeatedly. In the whole control process, the micro-light energy film continuously charges the energy storage element through the charging management circuit under 1000LX illumination, realizes that the picture brushing consumes less energy than the charging energy, and does not need external charging in the working process.

[0029] In the embodiment, the micro-light energy charging is used to realize the picture brushing energy self-constant in the low-power consumption mode. The problem that the battery is frequently charged during the picture brushing process of the cholesteric electronic paper display is solved.

[0030] In the embodiment, the control module is internally provided with a picture brushing timer. When the timing picture brushing instruction is acquired, the internal program will run according to the instruction to start one-time picture brushing. The instruction can be edited and written through an external interface, for example, once a minute, 60S is set and written. When the picture brushing is finished, the power indicator light will be turned off, the cholesteric display system will enter the sleep mode, the picture brushing is finished at this time, the main power circuit is turned off, and the control module controls the enable to be turned on again after 1 minute. The main power indicator light is turned on, the next picture brushing is run, and the circulation is continuously carried out. The picture brushing time interval can be modified according to the requirement.

[0031] Reference Figures 1-6 The control method of the self-powered cholesteric display screen display driving system provided by the application comprises the following steps: The control module controls the energy management module to stop supplying power to the display driving module in the sleep mode, and acquires the charging energy of the micro-light energy collection module under the ambient illumination; The control module processes the charging energy and the preset picture refreshing energy consumption. When the system reaches the preset wake-up time or the electric quantity of the energy storage element is higher than the preset refreshing threshold value, the control module outputs a wake-up control signal to the energy management module to obtain the system working voltage to start the display driving module; The control module controls the display driving module to execute one-time picture refreshing operation to obtain the picture refreshing completion result, and then outputs the sleep control signal again to make the system return to the sleep mode.

[0032] In the embodiment, the preset wake-up time and / or the preset refresh threshold are set by comparing the charging energy of the micro-light energy collection module per unit time and the energy consumption of a single image refresh, to ensure that the charging energy of the system within the preset wake-up time is greater than the energy consumption of a single image refresh.

[0033] In the embodiment, the specific value E of the charging energy per unit time is calculated as follows: ; Wherein, P is the power generation of the micro-light energy collection module under the current ambient illumination; and T is the system sleep time.

[0034] When the existing display screen is turned on and the image is refreshed, the electric energy and voltage will decrease with the increase of the number of image refresh, and finally be exhausted, so that the system will stop working. At this time, the energy storage element needs to be charged to make the whole machine work normally. The method uses the characteristics of the micro-light film that generates electricity under light to cooperate with the charging and discharging and power management software and hardware control system, so that the energy consumption of image refresh is less than the charging energy, and external charging is not needed in the working process. The user only needs to put the whole machine with the micro-light system in a light scene to refresh the image, without additional power supply, so that the machine can be used normally. The following are the relevant actual test data, the same system voltage, the same model of cholesteric display screen, the same illumination, and the same working time of 24 hours working comparison. When the traditional display screen system is powered by the battery to refresh the image, the 24-hour voltage change curve is as shown in Figure 5 The end voltage is less than the start voltage, and the voltage will decrease to the shutdown voltage threshold of 3V as time goes on, so that the charging is needed to work.

[0035] The working image refresh 24-hour voltage change curve of the display screen using the self-powered cholesteric display screen display driving system of the application is as shown in Figure 6 The battery voltage represents the voltage of the internal battery of the display screen, the end voltage is greater than the start voltage, and the final constant voltage is 4.1153V. The consumed energy is supplemented by self-power supply, the voltage is finally constant, and the additional charging is not needed to work continuously.

[0036] The above is only the preferred specific implementation of the application, but the protection scope of the application is not limited thereto. Any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the application within the technical range disclosed by the application, which should be covered within the protection scope of the application.

Claims

1. A self-powered cholesteric display screen display driving system, characterized by, The system comprises: a micro-light energy collection module for receiving ambient light and generating collected electric energy; an energy management module for receiving and managing the collected electric energy, charging management of an energy storage element inside the energy management module, providing charge-discharge loop protection, and step-up / step-down conversion and voltage stabilization of the output voltage of the energy storage element, and finally providing a stable system working voltage from the output end of the energy management module; a control module configured to output a sleep control signal or a wake-up control signal to control the opening and closing of the voltage output function of the energy management module; a display driving module for driving the cholesteric display screen to refresh images when the system working voltage is obtained; wherein the control module is configured to output a sleep control signal when the system is in sleep mode, so that the energy management module stops outputting the system working voltage, and at this time the micro-light energy collection module continues to charge the energy storage element; the control module is also configured to switch to working mode and output a wake-up control signal when the preset wake-up time is reached, so that the energy management module outputs the system working voltage, and the display driving module is controlled to perform an image refresh operation, and then the sleep control signal is output again to return the system to sleep mode.

2. The self-powered cholesteric display screen display driving system of claim 1, wherein, The micro-light energy collection module is a light energy film made of carbon-based material attached to the back of the cholesteric display screen.

3. The self-powered cholesteric display screen display driving system of claim 1, wherein, The energy management module comprises an energy collection chip, an energy storage element, a battery protection circuit and a step-up / step-down conversion circuit connected in sequence; The input end of the energy collection chip is connected to the micro-light energy collection module for maximum collection of the collected electric energy; The energy storage element is connected to the output end of the energy collection chip for storing electric energy; The input end of the step-up / step-down conversion circuit is connected to the energy storage element through the battery protection circuit, the output end of the step-up / step-down conversion circuit is used to provide the system working voltage, and the enable end of the step-up / step-down conversion circuit is connected to the control signal output end of the control module.

4. The self-powered cholesteric display screen display driving system of claim 3, wherein, The energy storage element is a lithium battery or a supercapacitor.

5. The self-powered cholesteric display screen display driving system of claim 1, wherein, The control module comprises a low-power microcontroller MCU, and the input / output port of the MCU constitutes the control signal output end.

6. The self-powered cholesteric display screen display driving system of claim 1, wherein, The system working voltage is a direct current voltage of 4.5V-21V.

7. A control method of a self-powered cholesteric display screen display driving system, characterized by, The system comprises the following steps: In sleep mode, the control module controls the energy management module to stop supplying power to the display driving module, and obtains the charging energy of the micro-light energy collection module under ambient light; The control module processes the charging energy and the preset image refresh energy consumption, and when the system reaches the preset wake-up time or the energy of the energy storage element is higher than the preset refresh threshold, the control module outputs a wake-up control signal to the energy management module to obtain the system working voltage to start the display driving module; The control module controls the display driving module to perform an image refresh operation to obtain an image refresh completion result, and then outputs a sleep control signal again to return the system to sleep mode.

8. The control method of a self-powered cholesteric display screen display driving system according to claim 7, characterized in that, The preset wake-up time and / or the preset refresh threshold are set by comparing the charging energy of the micro-light energy collection module per unit time with the energy consumption of a single image refresh, to ensure that the charging energy of the system within the preset wake-up time is greater than the energy consumption of a single image refresh.

9. The method of claim 7, wherein the method further comprises the step of: determining the number of the display units to be driven based on the number of the display units to be driven and the number of the display units to be driven in the previous frame. The specific value E of the charging energy per unit time is calculated as follows: ； Wherein, P is the power of the micro-light energy collection module under the current ambient illumination; T is the system sleep time.

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