Multi-dimensional parameter coordinated control method for wide-temperature-range liquid crystal display

Abstract

The application provides a multi-dimensional parameter collaborative control method for wide-temperature-range liquid crystal display, which is executed by a liquid crystal display master control unit and comprises the following steps: S1, periodically acquiring temperature detection data of a current environment and performing filtering pretreatment on the temperature detection data; and S2, reading a temperature interval state in which a current system is located, performing comparison operation on the pretreated temperature detection data and a hysteresis trigger threshold corresponding to an interval boundary, and determining whether an interval switching condition is met. Through multi-dimensional collaborative regulation of a power supply voltage, a bias voltage ratio and a scanning frame rate, liquid crystal molecules are forcibly driven at a high voltage under extremely low temperature, a pixel charging time is prolonged at a low frame rate to maintain picture density, and under super high temperature, the molecules are inhibited from being excessively active and crosstalk through a low voltage and a small bias voltage ratio, so that stable and clear display without white light emission, black light emission and crosstalk can be realized in a full temperature range of-40 DEG C to 80 DEG C, picture contrast fluctuation is effectively controlled, and wide-temperature-range display reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal display control technology, and in particular to a multi-dimensional parameter coordinated control method for a wide temperature range liquid crystal display. Background Technology

[0002] With the rapid development of new energy power generation, outdoor intelligent monitoring, and industrial field measurement and control, a large number of LCD display devices are being deployed in uncontrolled outdoor environments, requiring them to withstand both extreme low temperatures of -40℃ and ultra-high temperatures of 80℃. The physical properties of liquid crystal molecules, such as viscosity, response speed, and threshold voltage, are highly sensitive to ambient temperature: when the temperature decreases, the liquid crystal viscosity increases sharply, and the driving voltage is insufficient to deflect the molecules, resulting in a washed-out image and faded text; when the temperature increases, the liquid crystal threshold voltage decreases, making it easy for half-selected pixels to accidentally light up, resulting in a black background and vertical crosstalk stripes. Therefore, stable display over a wide temperature range is a core performance indicator for outdoor LCD devices.

[0003] Existing wide-temperature LCD control solutions generally adopt a hardware compensation architecture: the main control motherboard provides basic power supply and communication interface, the LCD module has an integrated driver chip, and the voltage regulation is achieved by relying on the hardware temperature sensor inside the driver chip and the fixed temperature gradient compensation curve pre-programmed at the factory; some solutions use an external thermistor voltage divider network in conjunction with an operational amplifier to form a hardware compensation circuit, which relies on the thermistor resistance to change the voltage division ratio with the temperature, thereby adjusting the driving voltage amplitude to adapt to the electro-optic characteristics of liquid crystal molecules at different temperatures.

[0004] The aforementioned existing technologies have two types of technical defects: 1. Insufficient compensation accuracy at extreme temperatures leads to a high risk of display failure. In extreme low-temperature environments of -40℃, the viscosity of liquid crystal molecules increases by more than two orders of magnitude compared to room temperature. The voltage boost of the hardware circuit is limited by the parameters of external components and the fixed compensation curve, resulting in insufficient voltage boost thrust. This can easily lead to problems such as screen whitening, faded text, or even complete disappearance of text. In ultra-high-temperature environments of 80℃, the activity of liquid crystal molecules increases, and the threshold voltage decreases. The fixed voltage drop slope cannot match the drift of the liquid crystal threshold voltage, resulting in a black screen background, severe vertical crosstalk stripes, and display failure.

[0005] 2. High hardware iteration costs and poor panel compatibility. Different models and batches of LCD panels have different physical characteristics. Traditional hardware compensation solutions require redesigning the external compensation circuit of the motherboard and adjusting the parameters of hardware components after replacing the panel. This results in a long development cycle, high adaptation costs, and an inability to quickly complete driver adaptation for multiple LCD panel specifications. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the existing technology. The present invention proposes a multi-dimensional parameter collaborative control method for wide temperature range liquid crystal displays.

[0007] To solve the aforementioned technical problems, the technical solution adopted by the present invention is as follows: A multi-dimensional parameter coordinated control method for a wide-temperature-range liquid crystal display, the method being executed by the liquid crystal display main control unit, includes the following steps: S1. Periodically acquire the temperature detection data of the current environment and perform filtering preprocessing on the temperature detection data; S2. Read the current temperature range status of the system, compare the preprocessed temperature detection data with the hysteresis trigger threshold of the corresponding range boundary, and determine whether the range switching condition is met. S3. If the interval switching condition is met, update the current temperature interval state to the target temperature interval; if not, maintain the current temperature interval state; according to the finally determined current temperature interval, call the parameter calculation model of the corresponding interval to calculate the multi-dimensional parameter configuration set at the current temperature. The multi-dimensional parameter configuration set includes at least the liquid crystal driving power supply voltage parameter, bias ratio parameter and scan frame rate parameter. S4. Send the multi-dimensional parameter configuration set to the liquid crystal driver chip through the parallel communication interface, and control the liquid crystal driver chip to adjust the output voltage of the internal charge pump, the voltage division ratio of the bias voltage divider network, and the timing frequency of the scan drive. S5. Repeat steps S1 to S4 to achieve dynamic coordinated control of LCD display parameters across the entire temperature range.

[0008] Preferably, the three-level temperature threshold is preset to divide the entire temperature range into four continuous theoretical intervals, namely the extreme cold zone, the low temperature zone, the normal temperature zone, and the high temperature zone; wherein the extreme cold zone corresponds to a temperature T < -20℃, the low temperature zone corresponds to -20℃ ≤ T < 0℃, the normal temperature zone corresponds to 0℃ ≤ T ≤ 40℃, and the high temperature zone corresponds to T > 40℃.

[0009] Preferably, the configuration rules for the multi-dimensional parameters corresponding to each temperature range are as follows: For extremely cold regions: the power supply voltage is increased by the highest boost factor, the scanning frame rate is reduced by the maximum descent, and the bias ratio is maintained at the standard value; For low-temperature regions: a moderate boost factor is used to increase the power supply voltage, a moderate descent factor is used to reduce the scan frame rate, and the bias ratio is maintained at the standard value; For the normal temperature range: the power supply voltage, bias ratio, and scan frame rate are all standard rated parameters; For high-temperature zones: reduce the power supply voltage, simultaneously reduce the bias ratio, and maintain the standard scan frame rate.

[0010] Preferably, the standard power supply voltage for the ambient temperature zone is 5V, the standard bias ratio is 1 / 4, and the standard scan frame rate is 60Hz. In the extremely cold region, the power supply voltage is 12V and the scanning frame rate is 30Hz when the ambient temperature is -40℃. In the high-temperature zone, the supply voltage is 3V and the bias ratio is 1 / 5 when the ambient temperature is 80℃.

[0011] Preferably, in step S2, each interval boundary is set with an independent heating trigger threshold and a cooling trigger threshold, and the hysteresis temperature difference is uniformly 4℃. Regarding the boundary between the normal temperature zone and the high temperature zone: the trigger threshold for the heating direction is 40℃, meaning that when the temperature rises from the normal temperature zone to the high temperature zone, it must be higher than 40℃ for a preset delay before switching to the high temperature zone parameter configuration; the trigger threshold for the cooling direction is 36℃, meaning that when the temperature falls from the high temperature zone to the normal temperature zone, it must be lower than 36℃ for a preset delay before switching to the normal temperature zone parameter configuration.

[0012] Preferably, in step S4, the liquid crystal display main control unit sends a register write instruction to the liquid crystal driver chip through an 8-bit parallel data bus in conjunction with the register address line and write enable signal line, directly rewriting the charge pump control register, bias configuration register and scan timing register inside the liquid crystal driver chip.

[0013] Preferably, the power supply voltage, bias ratio, and scan frame rate in each temperature range are calculated by fitting the temperature value with a piecewise linear function. The parameter values ​​of adjacent ranges are continuous without jumps at the boundary temperature, and the parameter values ​​change smoothly with the temperature.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves stable and clear display without whitening, blackening, or crosstalk across the entire temperature range of -40℃ to 80℃ by multi-dimensional coordinated control of power supply voltage, bias ratio, and scanning frame rate. Under extreme low temperatures, it forcibly drives liquid crystal molecules with high voltage and extends pixel charging time with low frame rate to maintain image density. Under ultra-high temperatures, it suppresses excessive molecular activity and crosstalk by low voltage and small bias ratio. The image contrast fluctuation is effectively controlled, thus improving the reliability of wide temperature range display.

[0015] This invention uses a pure software algorithm to replace the traditional hardware temperature measurement circuit and voltage regulation compensation network, without requiring modifications to the motherboard hardware design. When replacing LCD screens with different characteristics, only the compensation coefficients and threshold parameters in the software parameter mapping library need to be updated to complete the driver adaptation, shortening the adaptation cycle from several weeks to several hours and reducing development and material costs.

[0016] This invention employs a dual anti-shake mechanism combining hysteresis temperature difference and duration to eliminate the problem of repeated parameter switching caused by frequent fluctuations in ambient temperature near the critical point of the range. During parameter switching, the driving waveform does not change abruptly, and the screen does not flicker in a way that is perceptible to the naked eye, thus improving the display stability under outdoor conditions. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts. Wherein: Figure 1 This is a schematic diagram illustrating the principle of the multi-dimensional parameter collaborative control method of the present invention; Figure 2 This is a flowchart illustrating the steps of the multi-dimensional parameter collaborative control method of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with specific formula derivation, parameter definition and hardware implementation details. This embodiment is implemented under the premise of the technical solution of the present invention, and provides detailed implementation methods and specific calculation processes. However, the protection scope of the present invention is not limited to the following embodiment.

[0019] Please see Figure 1-2 This invention proposes a multi-dimensional parameter collaborative control method for wide-temperature-range liquid crystal displays.

[0020] The sole execution entity of this method is the LCD display main control unit, specifically an embedded microcontroller (MCU, such as the STM32 series), with built-in non-volatile Flash memory for storing control programs and parameter mapping libraries, and equipped with parallel peripheral interfaces and I2C peripheral interfaces. The main control unit connects to a high-precision digital temperature sensor (such as TMP102, temperature range -40℃~125℃, accuracy ±0.5℃) located in the backlight area of ​​the LCD panel via the I2C bus, and communicates with the LCD driver chip (such as the ST7920 type dot matrix LCD driver chip, which has a built-in programmable charge pump, bias voltage divider network and scan timing generator) through an 8-bit 8080 parallel interface.

[0021] To eliminate parameter ambiguity, the three types of driving parameters involved in this method are explicitly defined as follows: LCD driver power supply voltage This refers to the total pixel driving voltage output by the charge pump inside the liquid crystal driver chip, which serves as the amplitude reference for the row and column electrode driving waveforms. The unit is [unit missing]. This voltage directly determines the electric field strength at both ends of the liquid crystal molecules and is a core parameter affecting the driving capability.

[0022] Bias ratio This refers to the ratio of the bias voltage amplitude of the liquid crystal common electrode (COM terminal) to the driving supply voltage, i.e. The bias ratio determines the voltage division amplitude of the half-gated pixel. Reducing the bias ratio can decrease the electric field strength of the half-gated pixel and suppress crosstalk.

[0023] Scan frame rate : refers to the number of times per second that all rows of pixels on the screen are refreshed, measured in Hz; the lower the frame rate, the longer the gating and charging time of a single row of pixels, and the more fully the liquid crystal molecules are deflected, which can improve the contrast of the picture at low temperatures.

[0024] The theoretical temperature range is divided into three preset temperature threshold levels: the first threshold... Second threshold Third threshold The operating temperature range of -40℃ to 80℃ is divided into four continuous theoretical intervals: Extreme cold regions: Low temperature zone: Normal temperature zone: High temperature zone: To avoid frequent temperature fluctuations near the critical points of the intervals, which would cause repeated parameter switching, a hysteretic state machine logic based on the current state is adopted. A heating trigger threshold and a cooling trigger threshold are set for each interval boundary, and the hysteretic temperature difference is uniformly set. Set the delay duration at the same time. Only when the temperature is continuous The interval switching will only be executed when the duration meets the trigger threshold condition. The trigger rules for each boundary are as follows: Let the current interval of the system be . The current sampling temperature is The duration for which the threshold condition is continuously met is The interval switching indicator is The decision logic is as follows: In the formula Indicates the execution of range switching and updating. The target interval; This indicates that the current interval state will be maintained and the parameters will not be changed.

[0025] All parameters are fitted using piecewise linear functions, with parameter values ​​at the boundary temperatures of adjacent intervals being completely continuous, ensuring no abrupt changes during the switching process. All compensation coefficients are obtained through high and low temperature electro-optical characteristic tests of the target LCD panel, so only the coefficients need to be updated to complete the adaptation when replacing the panel.

[0026] The supply voltage gradually increases as the temperature decreases to compensate for the decrease in the driving ability of liquid crystal molecules at low temperatures; and gradually decreases as the temperature increases to suppress excessive molecular activity at high temperatures.

[0027] normal temperature zone Maintain standard rated voltage In the formula This is the reference supply voltage for room temperature.

[0028] Low temperature zone Voltage increases linearly with decreasing temperature, compensating for initial drive attenuation. In the formula: The low-temperature pressure rise coefficient is taken in this embodiment. ; This is the upper limit temperature of the low-temperature zone.

[0029] Verification Implementation: Substitution , It is continuous with the boundary of the normal temperature zone; substituting... , .

[0030] Extreme cold region : Employing a larger boost coefficient to forcibly drive high-viscosity liquid crystal molecules In the formula: for The corresponding voltage value (8V, continuous with the boundary of the low temperature zone); The extreme cold pressure coefficient is taken in this embodiment. ; This represents the upper limit temperature for extremely cold regions.

[0031] Verification Implementation: Substitution , It is continuous with the boundary of the low-temperature region; substituting... , This meets the high-thrust drive requirements under extreme low temperatures.

[0032] High temperature zone Voltage decreases linearly with increasing temperature, inhibiting excessive molecular activity. In the formula: For the high-temperature pressure drop coefficient, this embodiment takes... ; This is the lower limit temperature of the high-temperature zone.

[0033] Verification: Substitute T=40℃, It is continuous with the boundary of the normal temperature zone; substituting... , This effectively reduces the amplitude of liquid crystal driving at high temperatures.

[0034] The bias ratio is calculated in a temperature-coordinated manner. The bias ratio decreases linearly with increasing temperature only in the high-temperature region. Vertical crosstalk is suppressed by reducing the amplitude of the half-gated voltage divider. In the low-temperature and normal-temperature ranges, the liquid crystal threshold voltage is relatively high, and there is no risk of crosstalk. The standard bias ratio can be maintained.

[0035] Normal temperature zone, low temperature zone, extremely cold zone Maintain standard bias ratio High temperature zone The bias ratio decreases linearly with increasing temperature. In the formula: The bias ratio temperature coefficient is taken in this embodiment. .

[0036] Verification Implementation: Substitution , It is continuous with the boundary of the normal temperature zone; substituting... , By reducing the bias ratio to change the physical voltage gradient, screen blacking and vertical crosstalk are effectively suppressed, and the calculation is correct.

[0037] The calculated scan frame rate decreases linearly with decreasing temperature only in low-temperature and extremely cold regions. By extending the charging time of a single row of pixels, the image contrast is improved, preventing the image from fading. In high-temperature and normal-temperature ranges, the LCD response speed is fast, maintaining a standard frame rate to ensure smooth image display.

[0038] Normal temperature zone, high temperature zone Maintain standard scan frame rate Low temperature zone Frame rate decreases linearly with temperature. In the formula: For the low-temperature frame rate coefficient, this embodiment takes... .

[0039] Verification Implementation: Substitution , It is continuous with the boundary of the normal temperature zone; substituting... , The calculation is correct.

[0040] Extreme cold region : Adopt a larger frame rate reduction to maintain image contrast In the formula: The corresponding frame rate value (50Hz, continuous with the boundary of the low temperature zone). For the extreme cold frame rate coefficient, this embodiment takes... .

[0041] Numerical verification: Substitution , It is continuous with the boundary of the low-temperature region; substituting... , By reducing the scan frame rate, the pixel charging time is increased, preventing the image from fading in extremely cold environments, and the calculation is accurate.

[0042] After the main control unit calculates the multi-dimensional parameter configuration set at the current temperature, it performs a register write operation through an 8-bit parallel interface: Output register address to address bus, pull chip select signal and write enable signal low; The parameter configuration values ​​are converted into the corresponding register encoded values ​​and output to the data bus; Pulling the write enable signal high drives the chip to latch data and update the internal module status: the charge pump module adjusts the output voltage amplitude, the bias voltage divider network switches the voltage divider resistor ratio, and the scan timing generator adjusts the row scan clock frequency. After all parameters have been written, release the bus and wait for the next sampling cycle.

[0043] Example Example 1: Control process in an extremely cold environment of -40℃ The LCD main control unit reads temperature sensor data via the I2C bus at a sampling frequency of 1Hz, and obtains the current ambient temperature after mean filtering. ; The current system status is read as extremely cold region. The switchover condition was not met when compared with the boundary threshold of the extreme cold region, so the extreme cold region status was maintained. Call the extreme cold region parameter calculation model and substitute the values ​​into the formula to calculate: Power supply voltage: Bias ratio: Scan frame rate: The main control unit sequentially writes the charge pump control register (corresponding to 12V output), bias configuration register (corresponding to 1 / 4 bias), and scan timing register (corresponding to 30Hz frame rate) to the LCD driver chip through an 8-bit parallel interface. The driver chip updates its internal hardware status, forcibly driving the high-viscosity liquid crystal molecules with a high voltage of 12V, and ensuring that the pixels are fully charged with a low frame rate of 30Hz. The test results show that the contrast of the display is close to that of room temperature, with no whitening and clear and stable text.

[0044] Example 2: Control process under ultra-high temperature environment of 80℃ The current ambient temperature is obtained by sampling and filtering by the main control unit of the LCD display. ; The current system status is read as being in the high-temperature zone. The temperature T=80℃ is compared with the high-temperature zone boundary threshold. The switching condition is not met, so the high-temperature zone status is maintained. Call the high-temperature region parameter calculation model and substitute the values ​​into the formula to calculate: Power supply voltage: Bias ratio: Scan frame rate: The main control unit writes the corresponding register to the driver chip through the parallel interface, pulls the charge pump output voltage down to 3V, adjusts the bias voltage divider ratio to 1 / 5, and keeps the scan frame rate at 60Hz. The driver chip reduces the driving voltage and bias amplitude to suppress the excessive activity of liquid crystal molecules at high temperatures. Tests show that the screen does not blacken, vertical crosstalk stripes are completely eliminated, and the display is stable.

[0045] Example 3: Anti-shake switching process in the critical temperature range As the ambient temperature decreases from 50℃ towards room temperature, the initial system state is in the high-temperature zone, with the following parameters: power supply voltage 3.5V, bias ratio 0.2375, and frame rate 60Hz. When the temperature drops to 39℃, the current state is the high temperature zone. The cooling trigger threshold is 36℃. Since 39℃ > 36℃, the switching condition is not met, and the main control unit maintains the high temperature zone parameters. When the temperature continues to drop to 35.8℃ and is below 36℃ for 2 consecutive seconds, the cooling trigger threshold and delay duration requirements are met, the interval switching flag is set to 1, and the system status is updated to the normal temperature zone. The main control unit calls the normal temperature range parameter model to obtain the standard parameter set: power supply voltage 5V, bias ratio 0.25, frame rate 60Hz; The main control unit writes to the corresponding registers one by one to complete the parameter switching. Since the parameters of the piecewise linear model are continuous at the boundary, there are no sudden changes in the driving waveform during the switching process, and there is no flickering that can be detected by the naked eye on the screen. This effectively avoids the problem of frequent parameter switching caused by repeated temperature fluctuations around 40℃.

[0046] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A multi-dimensional parameter coordinated control method for a wide-temperature-range liquid crystal display, characterized in that, The method is executed by the liquid crystal display main control unit and includes the following steps: S1. Periodically acquire the temperature detection data of the current environment and perform filtering preprocessing on the temperature detection data; S2. Read the current temperature range status of the system, compare the preprocessed temperature detection data with the hysteresis trigger threshold of the corresponding range boundary, and determine whether the range switching condition is met. S3. If the interval switching condition is met, update the current temperature interval state to the target temperature interval; if not, maintain the current temperature interval state; according to the finally determined current temperature interval, call the parameter calculation model of the corresponding interval to calculate the multi-dimensional parameter configuration set at the current temperature. The multi-dimensional parameter configuration set includes at least the liquid crystal driving power supply voltage parameter, bias ratio parameter and scan frame rate parameter. S4. Send the multi-dimensional parameter configuration set to the liquid crystal driver chip through the parallel communication interface, and control the liquid crystal driver chip to adjust the output voltage of the internal charge pump, the voltage division ratio of the bias voltage divider network, and the timing frequency of the scan drive. S5. Repeat steps S1 to S4 to achieve dynamic coordinated control of LCD display parameters across the entire temperature range.

2. The multi-dimensional parameter coordinated control method for wide-temperature-range liquid crystal displays according to claim 1, characterized in that, The three preset temperature thresholds divide the entire temperature range into four continuous theoretical intervals: the extreme cold zone, the low temperature zone, the normal temperature zone, and the high temperature zone. The extreme cold zone corresponds to a temperature T < -20℃, the low temperature zone corresponds to -20℃ ≤ T < 0℃, the normal temperature zone corresponds to 0℃ ≤ T ≤ 40℃, and the high temperature zone corresponds to T > 40℃.

3. The multi-dimensional parameter coordinated control method for wide-temperature-range liquid crystal displays according to claim 2, characterized in that, The configuration rules for the multi-dimensional parameters corresponding to each temperature range are as follows: For extremely cold regions: the power supply voltage is increased by the highest boost factor, the scanning frame rate is reduced by the maximum descent, and the bias ratio is maintained at the standard value; For low-temperature regions: a moderate boost factor is used to increase the power supply voltage, a moderate descent factor is used to reduce the scan frame rate, and the bias ratio is maintained at the standard value; For the normal temperature range: the power supply voltage, bias ratio, and scan frame rate are all standard rated parameters; For high-temperature zones: reduce the power supply voltage, simultaneously reduce the bias ratio, and maintain the standard scan frame rate.

4. The multi-dimensional parameter coordinated control method for wide-temperature-range liquid crystal displays according to claim 3, characterized in that, The standard power supply voltage for the ambient temperature zone is 5V, the standard bias ratio is 1 / 4, and the standard scan frame rate is 60Hz. In the extremely cold region, the power supply voltage is 12V and the scanning frame rate is 30Hz when the ambient temperature is -40℃. In the high-temperature zone, the supply voltage is 3V and the bias ratio is 1 / 5 when the ambient temperature is 80℃.

5. The multi-dimensional parameter coordinated control method for wide-temperature-range liquid crystal displays according to claim 2, characterized in that, In step S2, each interval boundary is set with an independent heating trigger threshold and a cooling trigger threshold, and the hysteresis temperature difference is uniformly 4℃. Regarding the boundary between the normal temperature zone and the high temperature zone: the trigger threshold for the heating direction is 40℃, meaning that when the temperature rises from the normal temperature zone to the high temperature zone, it must be higher than 40℃ for a preset delay before switching to the high temperature zone parameter configuration; the trigger threshold for the cooling direction is 36℃, meaning that when the temperature falls from the high temperature zone to the normal temperature zone, it must be lower than 36℃ for a preset delay before switching to the normal temperature zone parameter configuration.

6. The multi-dimensional parameter coordinated control method for a wide-temperature-range liquid crystal display according to claim 1, characterized in that, In step S4, the main control unit of the liquid crystal display sends a register write instruction to the liquid crystal driver chip through an 8-bit parallel data bus in conjunction with the register address line and write enable signal line, directly rewriting the charge pump control register, bias configuration register and scan timing register inside the liquid crystal driver chip.

7. The multi-dimensional parameter coordinated control method for a wide-temperature-range liquid crystal display according to claim 3, characterized in that, The power supply voltage, bias ratio, and scan frame rate within each temperature range are calculated by fitting the temperature value with a piecewise linear function. The parameter values ​​at the boundary temperature of adjacent ranges are continuous without jumps, and the parameter values ​​change smoothly with temperature.

Images