Instrument intelligent screen display switching circuit and method

Abstract

The present invention discloses an instrument intelligent screen display switching circuit and method. The instrument intelligent screen display switching circuit comprises a mainboard, a hysteresis comparator U1, a voltage regulator tube DZ1, a voltage-dividing resistor R1, a sampling resistor R2, a feedback resistor R5, a diode D1, a photosensitive element D1T, a voltage-dividing resistor R3, a sampling resistor R4 and a photosensitive element D2T. An MCU and a display screen module are arranged in the mainboard. The MCU samples the output end connected to the hysteresis comparator U1 and controls the connection to the display screen module. In the present invention, when a long touch is required to switch the screen display mode, the screen display mode can be switched immediately when the touch time is reached even if the touch is not ended, and the startup speed is fast and the reliability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent instruments, and in particular to an intelligent screen display switching circuit and method for an instrument. Background Art

[0002] Flow meters are commonly used in people's production and life. According to the different types of flow, they can be divided into water meters, gas meters, oil meters, etc. Among them, in order to realize data display and debugging, most meters are equipped with a display module and a corresponding display switching circuit on the front side of the shell.

[0003] like Figure 1 As shown, the instrument screen display switching circuit includes a mainboard and a screen display switching detection circuit, which is composed of a resistor R2, a resistor R1 and a photosensitive element D1T. One end of the resistor R1 is connected to the power supply end Vcc of the mainboard, and the other end is connected to the collector of the photosensitive element D1T. The emitter of the photosensitive element D1T is connected to GND. The connection end of the resistor R1 and the photosensitive element D1T is connected to the sampling end of the mainboard through the resistor R2. The mainboard is provided with an ADC, an MCU and a display screen module. The data input end of the ADC is connected to the sampling end of the mainboard to obtain an analog sampling signal from the screen display switching detection circuit. The data output end of the ADC is connected to the data input end of the MCU to send a digital sampling signal to the MCU. The control end of the MCU is connected to the display screen module to control the display screen module to switch the screen display content.

[0004] The working principle of the instrument screen display switching circuit is: when the screen display content needs to be switched, manually touch the photosensitive element D1T for a few milliseconds or seconds and then release it. At this time, the timing diagram of the mainboard detecting the sampling data is as follows: Figure 2 That is, when the photosensitive element is touched manually, the sampling value will deflect twice within a relatively long time interval t1. According to the actual time interval t2 between the two deflections, the current screen content can be switched to the next screen content, or the current screen mode can be switched to the next screen mode.

[0005] The existing instrument screen display switching circuit has the following problems:

[0006] 1. The instrument is easily affected by environmental factors, resulting in incorrect switching of the screen display content. For example, when there is a cover on the instrument surface, the cover is closed and then quickly opened, or when there is no cover on the instrument surface or the cover is open, due to the various possibilities of the instrument installation position, there are doors, cars, people and other obstructions that quickly move in front of the instrument, which will cause the sampling value to flip a second time within the set time interval, resulting in incorrect switching of the screen display.

[0007] 2. When the shielding cover is closed or there is an obstruction in front of the instrument, the sampling value will be deflected for the first time. The purpose of detecting whether the sampling value will be reversed for the second time is to distinguish whether it is a human touch or the shielding cover is closed or there is an obstruction in front of the instrument. This will result in the need to wait until the touch ends before the screen display switch can be started, and the switching speed is slow and the sensitivity is low. Moreover, when the touch time is too long, only one flip may be detected within the set time interval, and the next screen display content cannot be switched, and the reliability is poor. Summary of the invention

[0008] The purpose of the present invention is to provide an instrument intelligent screen display switching circuit and method to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An instrument intelligent screen display switching circuit, including a mainboard, a hysteresis comparator U1, a voltage regulator tube D Z1 , voltage divider resistor R1, sampling resistor R2, feedback resistor R5, diode D1, photosensitive element D1T, voltage divider resistor R3, sampling resistor R4 and photosensitive element D2T;

[0011] The mainboard is provided with an MCU and a display screen module. The MCU samples the output end of the hysteresis comparator U1 and controls the display screen module.

[0012] One end of the voltage-dividing resistor R1 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the collector of the photosensitive element D1T, the emitter of the photosensitive element D1T is connected to GND, and the cathode of the diode D1 and the collector of the photosensitive element D1T are also connected to the non-inverting input terminal of the hysteresis comparator U1 through the sampling resistor R2;

[0013] One end of the voltage divider resistor R3 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the collector of the photosensitive element D2T. The emitter of the photosensitive element D2T is connected to GND. The voltage divider resistor R3 and the collector of the photosensitive element D1T are also connected to the inverting input terminal of the hysteresis comparator U1 through the sampling resistor R4. A feedback resistor R5 is connected between the output terminal and the non-inverting input terminal of the hysteresis comparator U1. A voltage regulator tube D is connected between the output terminal of the hysteresis comparator U1 and the ground. Z1 .

[0014] As a further technical solution of the present invention, the voltage-dividing resistor R1, the sampling resistor R2, the diode D1, and the photosensitive element D1T constitute a first sampling circuit.

[0015] As a further technical solution of the present invention, the voltage-dividing resistor R3, the sampling resistor R4, and the photosensitive element D2T constitute a second sampling circuit.

[0016] As a further technical solution of the present invention, the resistance values ​​of the voltage-dividing resistors R1 and R3 are the same.

[0017] As a further technical solution of the present invention, the resistance values ​​of the sampling resistors R2 and R4 are the same.

[0018] As a further technical solution of the present invention, the photosensitive element D1T and the photosensitive element D2T are of the same model.

[0019] As a further technical solution of the present invention, when the light intensity is higher, the current in the photosensitive elements D1T and D2T is larger, and the corresponding voltage sampling value connected to the input terminal of the hysteresis comparator U1 is smaller.

[0020] As a further technical solution of the present invention, the photosensitive elements D1T and D2T are arranged at the same position of the smart meter body, and are subject to the same environmental factors and the same light intensity.

[0021] A method for switching an instrument intelligent screen display, using the above-mentioned switching circuit, comprises the following steps:

[0022] Step (1), synchronously sampling the electrical physical quantities of the first photosensitive element D1T and the second photosensitive element D2T in real time; wherein, under the same light intensity, the sampling values ​​corresponding to the first photosensitive element D1T and the second photosensitive element D2T are the same;

[0023] Step (2): adjust the sampling value of the first photosensitive element D1T downward by U D , and will reduce U D The sampling value of the first photosensitive element D1T is compared with the sampling value of the second photosensitive element D2T;

[0024] Step (3): if U is lowered D After that, the sampling value of the first photosensitive element D1T is greater than the sampling value of the second photosensitive element D2T, indicating that D1T must be touched manually. At this time, the duration t that the sampling value of D1T is higher than the sampling value of D2T is recorded within the set time T1. D If the sampling value of the first photosensitive element D1T is not greater than the sampling value of the second photosensitive element D2T, it means that there is definitely no human touch at this time, and the process returns to step (1), wherein the setting time T1 is determined according to the minimum time value required for the touch to switch the screen display mode, that is, when the screen display mode needs to be switched, the shortest time required to touch the photosensitive element D1T is determined;

[0025] Step (4), determine whether the duration t is less than the set time T1. If it is less than the set time T1, switch the current display content in the current display mode to the next display content; if it is not less than the set time T1, switch the current display mode to the next display mode.

[0026] As a further technical solution of the present invention, U D The determination method is as follows: a. Uniformly set m different light intensities and place the two photosensitive elements D1T and D2T in these m different light intensities respectively; b. Without touching, respectively record the n measurement values ​​of the two photosensitive elements D1T and D2T under the i-th light intensity, which are recorded as c. Calculate the average value of n measured values ​​of D1T at the i-th light intensity and the average of n measurements of D2T at the i-th light intensity d. Calculate the n measured values ​​of D1T at the i-th light intensity respectively and The absolute value of the difference and the n measured values ​​of D2T at the i-th light intensity and The absolute value of the difference; e. D Take 2|u| max +Δu, where |u| max is the maximum value among all absolute values, and Δu is the current conduction voltage of all diodes greater than 2|u| max And with 2|u| max The closest on-state voltage is 2|u| max The difference.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. By adding a few simple electronic devices, the judgment of the sampling value flipping twice within the set time is converted into the judgment of the difference between the two sampling values, and the implementation method is different;

[0029] 2. Since the two photosensitive elements are both installed on the meter, they are close to each other and face the same environment. The difference between the corresponding sampling values ​​of the two is used to determine whether to switch the screen display. This can eliminate the influence of environmental factors such as the cover being closed and then opened or the cover moving in front of the meter on the sampling value of a single photosensitive element, which may cause the screen display switching to start incorrectly. This is easy to implement and low cost.

[0030] 3. By setting a diode, the sampling value of the touched photosensitive element is lowered, thereby avoiding the phenomenon of frequent false start of screen display switching due to measurement error when the photosensitive element is not touched, and improving the switching reliability.

[0031] 4. By setting the hysteresis comparator, the screen display can be switched directly based on the analog signal, thus avoiding the analog-to-digital conversion and meeting the application requirements of the instrument MCU with a short wake-up time per cycle.

[0032] 5. When long touch is required to switch the screen display mode, the screen display mode can be switched immediately when the touch time is reached, even if the touch has not ended, with fast startup speed and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the existing starting circuit diagram;

[0034] Figure 2 It is the sampling timing diagram;

[0035] Figure 3 is a sampling circuit diagram of the present invention;

[0036] Figure 4 It is the principle diagram of the present invention;

[0037] Figure 5 Schematic diagram of hysteresis comparator output.

[0038] Figure 6 The figure is a flow chart of the instrument intelligent screen display switching method. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1: Please refer to Figure 3 , an instrument intelligent screen display switching circuit, including: a main board, a hysteresis comparator U1, a voltage regulator tube D Z1 , voltage dividing resistor R1, sampling resistor R2, feedback resistor R5, diode D1, photosensitive element D1T, voltage dividing resistor R3, sampling resistor R4, photosensitive element D2T.

[0041] Among them, the voltage-dividing resistor R1, the sampling resistor R2, the diode D1, and the photosensitive element D1T constitute the first screen display switching detection circuit, and the voltage-dividing resistor R3, the sampling resistor R4, and the photosensitive element D2T constitute the second screen display switching detection circuit. In the first screen display switching detection circuit, one end of the voltage-dividing resistor R1 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the collector of the photosensitive element D1T, and the emitter of the photosensitive element D1T is connected to GND. The cathode of the diode D1 and the collector of the photosensitive element D1T are also connected to the non-inverting input terminal of the hysteresis comparator U1 through the sampling resistor R2. In the second screen display switching detection circuit, one end of the voltage-dividing resistor R3 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the collector of the photosensitive element D2T, and the emitter of the photosensitive element D2T is connected to GND. The voltage divider resistor R3 and the collector of the photosensitive element D1T are also connected to the inverting input terminal of the hysteresis comparator U1 through the sampling resistor R4. A feedback resistor R5 is connected between the output terminal and the non-inverting input terminal of the hysteresis comparator U1, and a voltage regulator tube D is connected between the output terminal and the ground. Z1 The mainboard is provided with an MCU and a display screen module. The MCU samples the output end of the hysteresis comparator U1 and controls the display screen module.

[0042] Embodiment 2, based on embodiment 1, the resistance values ​​of the voltage divider resistors R1 and R3 are the same, the resistance values ​​of the sampling resistors R2 and R4 are the same, and the photosensitive elements D1T and D2T are of the same model. When the light intensity is higher, the current in the photosensitive elements D1T and D2T is larger, and the corresponding voltage sampling value connected to the input terminal of the hysteresis comparator U1 is smaller.

[0043] The working principle of this design is:

[0044] (1) The photosensitive elements D1T and D2T are set at the same position of the body of the smart meter, with the same environmental factors and the same light intensity.

[0045] (2) When the screen display does not need to be switched, the light intensity of the photosensitive elements D1T and D2T is the same, but due to the voltage divider effect of the diode D1, the voltage divider size is the conduction voltage U of the diode D1. D, the voltage value of the non-inverting input terminal of the hysteresis comparator U1 will be lower than the voltage of its inverting input terminal, and the difference between the voltage value of the non-inverting input terminal and the voltage of the inverting input terminal will be lower than the low voltage threshold -Δu of the hysteresis comparator U1, and the output of the hysteresis comparator U1 is low level. The MCU detects the low level and controls the display screen module to maintain the current screen display content. By setting the diode D1, under the same light intensity, the voltage value of the non-inverting input terminal of the hysteresis comparator U1 can be forced to be lower than the voltage value of the inverting input terminal. This avoids the phenomenon that when the diode D1 is not set, even if the light intensity is the same, due to the influence of the measurement error, the voltage value of the non-inverting input terminal of the hysteresis comparator U1 is sometimes higher than the voltage value of the inverting input terminal, and sometimes lower than the voltage value of the inverting input terminal, thereby causing the screen to repeatedly switch incorrectly.

[0046] (3) When the screen display needs to be switched, manually touch the photosensitive element D1T. If the current screen display mode needs to be switched to the next screen display mode, such as the maintenance screen display mode, long touch the photosensitive element D1T; if the current screen display content in the current screen display mode needs to be switched to the next screen display content, short touch the photosensitive element D1T. As the light intensity of the photosensitive element D1T decreases, its current will be significantly reduced, and then the voltage value at the non-inverting input terminal of the hysteresis comparator U1 will increase and be higher than the voltage at its inverting input terminal. The difference between the voltage value at the non-inverting input terminal and the voltage at the inverting input terminal will be higher than the high voltage threshold Δu of the hysteresis comparator U1, and the hysteresis comparator U1 outputs a high level. The MCU detects a high level. If the duration of the high level is long, the control display screen module switches the current screen display mode to the next screen display mode; if the duration of the high level is short, the control display screen module switches the current screen display content in the current screen display mode to the next screen display content.

[0047] like Figure 4 As shown in the figure, the thick red solid line shows that in the case of touch, the sampling voltage value corresponding to D1T, that is, the voltage value of the non-inverting input terminal of the hysteresis comparator U1 changes with the ambient light intensity; the thin blue solid line shows that in the case of no touch, the sampling voltage value corresponding to D2T, that is, the voltage value of the inverting input terminal of the hysteresis comparator U1 changes with the ambient light intensity; the thick red dotted line shows that in the case of touch, the sampling voltage value corresponding to D1T, that is, the voltage value of the non-inverting input terminal of the hysteresis comparator U1 changes with the ambient light intensity.

[0048] Of course, in reality, the changes in the D1T and D2T sampling voltage values ​​with light intensity do not necessarily show the same Figure 4 The linear relationship shown in Figure 4 This is a simplified diagram for illustration purposes only. However, Figure 4 This is the same as the actual trend that the D1T and D2T sampling voltage values ​​decrease as the light intensity increases.

[0049] Without touching D1T, the light intensity of D1T and D2T is the same, but due to the voltage drop effect of diode D1 (the voltage drop is Figure 4 U D ), even if the sampling error is considered (the limit sampling error is U D -Δu), the sampling voltage value of D1T will also be lower than that of D2T, such as Figure 4 As shown by point A on the thick red solid line and point B on the thin blue solid line, the output of the hysteresis comparator U1 is a low level at this time.

[0050] When the screen display needs to be switched, the D1T is touched manually, and the light intensity of the D1T decreases. At this time, the sampling voltage value of the D1T will increase significantly. Figure 4 As shown in Figure 1, when the light intensity is much higher than a certain intensity E0, the sampling voltage value of D1T after touch will be higher than the sampling voltage value of D2T, such as Figure 4 As shown by point C on the red dotted line in Figure 5 As shown, the difference between the voltage value at the non-inverting input terminal and the voltage at the inverting input terminal of the hysteresis comparator U1 is higher than the high voltage threshold Δu of the hysteresis comparator U1, and the output of the hysteresis comparator U1 is a high level.

[0051] When affected by environmental factors, such as when the shielding cover set on the instrument surface is closed or when there is an obstruction in front of the instrument without setting the shielding cover, the light intensity of D1T and D2T will be weakened, and the corresponding sampling voltage values ​​will increase by the same amplitude, respectively. Figure 4 As shown at points C and D in FIG. 1 , at this time, the sampling voltage value of D1T is still lower than that of D2T, and the output of the hysteresis comparator U1 is still at a low level, thereby avoiding the phenomenon of miscutting of the screen display content.

[0052] When the ambient light intensity is lower than a certain value, such as Figure 4 When the light intensity is slightly higher or lower than E0, when D1T is touched, the sampling voltage value of D1T will increase. However, due to the small increase, the difference between the voltage value at the non-inverting input terminal and the voltage at the inverting input terminal of the hysteresis comparator U1 will be lower than the high voltage threshold Δu of the hysteresis comparator U1. At this time, the hysteresis comparator U1 will still output a low level and will not switch the screen display, thereby avoiding the phenomenon of screen display miscutting when the light intensity is too low.

[0053] based on Figure 3 The intelligent screen display switching circuit of the instrument in Figure 6 As shown, the steps of the instrument intelligent screen display switching method are as follows:

[0054] (1) The electrical physical quantities of the first photosensitive element D1T and the second photosensitive element D2T are synchronously sampled in real time; wherein, under the same light intensity, the sampling values ​​corresponding to the first photosensitive element D1T and the second photosensitive element D2T are the same.

[0055] (2) Adjust the sampling value of the first photosensitive element D1T downward by U D , and will reduce U D The sampled value of the first photosensitive element D1T is compared with the sampled value of the second photosensitive element D2T.

[0056] Among them, U D The method of determining is:

[0057] a. Uniformly set m different light intensities, and place the two photosensitive elements D1T and D2T in these m different light intensities respectively;

[0058] b. Without touching, record the n measured values ​​of the two photosensitive elements D1T and D2T at the i-th light intensity, respectively, and record them as

[0059] c. Calculate the average value of n measured values ​​of D1T at the i-th light intensity and the average of n measurements of D2T at the i-th light intensity

[0060] d. Calculate the n measured values ​​of D1T at the i-th light intensity respectively and The absolute value of the difference and the n measured values ​​of D2T at the i-th light intensity and The absolute value of the difference;

[0061] e. Will U D Take 2|u| max +Δu, where |u| max is the maximum value among all absolute values, and Δu is the current conduction voltage of all diodes greater than 2|u| max And with 2|u| max The closest on-state voltage is 2|u| max The difference.

[0062] (3) If U is lowered D After that, the sampling value of the first photosensitive element D1T is greater than the sampling value of the second photosensitive element D2T, indicating that D1T must be touched manually. At this time, the duration t that the sampling value of D1T is higher than the sampling value of D2T is recorded within the set time T1. DIf the sampling value of the first photosensitive element D1T is not greater than the sampling value of the second photosensitive element D2T, it means that there is definitely no human touch at this time, and the process returns to step (1), wherein the setting time T1 is determined according to the minimum time value required for the touch to switch the screen display mode, that is, when the screen display mode needs to be switched, the shortest time required to touch the photosensitive element D1T is determined.

[0063] (4) Determine whether the duration t is less than the set time T1. If so, switch the current display content in the current display mode to the next display content; if not, switch the current display mode to the next display mode.

[0064] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0065] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An instrument intelligent screen display switching circuit, characterized in that: Including main board, hysteresis comparator U1, voltage regulator D Z1 , voltage divider resistor R1, sampling resistor R2, feedback resistor R5, diode D1, photosensitive element D1T, voltage divider resistor R3, sampling resistor R4 and photosensitive element D2T; The mainboard is provided with an MCU and a display screen module. The MCU samples the output end of the hysteresis comparator U1 and controls the display screen module. One end of the voltage-dividing resistor R1 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the collector of the photosensitive element D1T, the emitter of the photosensitive element D1T is connected to GND, and the cathode of the diode D1 and the collector of the photosensitive element D1T are also connected to the non-inverting input terminal of the hysteresis comparator U1 through the sampling resistor R2; One end of the voltage-dividing resistor R3 is connected to the power supply terminal Vcc of the mainboard, and the other end is connected to the collector of the photosensitive element D2T. The emitter of the photosensitive element D2T is connected to GND. The voltage-dividing resistor R3 and the collector of the photosensitive element D1T are also connected to the inverting input terminal of the hysteresis comparator U1 through the sampling resistor R4. A feedback resistor R5 is connected between the output terminal and the non-inverting input terminal of the hysteresis comparator U1. A voltage regulator tube D is connected between the output terminal of the hysteresis comparator U1 and the ground. Z1 .

2. The intelligent screen display switching circuit of an instrument according to claim 1, characterized in that: The voltage-dividing resistor R1 , the sampling resistor R2 , the diode D1 , and the photosensitive element D1T constitute a first sampling circuit.

3. The intelligent screen display switching circuit of an instrument according to claim 1, characterized in that: The voltage-dividing resistor R3, the sampling resistor R4, and the photosensitive element D2T form a second sampling circuit.

4. The intelligent display switching circuit of an instrument according to claim 1, characterized in that: The voltage-dividing resistors R1 and R3 have the same resistance value.

5. The intelligent display switching circuit of an instrument according to claim 1, characterized in that: The sampling resistors R2 and R4 have the same resistance value.

6. The intelligent screen display switching circuit of an instrument according to claim 1, characterized in that: The photosensitive element D1T and the photosensitive element D2T are of the same model.

7. The intelligent display switching circuit of an instrument according to claim 1, characterized in that: When the light intensity is higher, the current in the photosensitive elements D1T and D2T is larger, and the corresponding voltage sampling value connected to the input terminal of the hysteresis comparator U1 is smaller.

8. The intelligent display switching circuit for an instrument according to claim 1, characterized in that: The photosensitive elements D1T and D2T are arranged at the same position of the smart meter body, and are subject to the same environmental factors and the same light intensity.

9. A method for switching intelligent display of an instrument, characterized in that: The switching circuit according to any one of claims 1 to 8 comprises the following steps: Step (1), synchronously sampling the electrical physical quantities of the first photosensitive element D1T and the second photosensitive element D2T in real time; wherein, under the same light intensity, the sampling values ​​corresponding to the first photosensitive element D1T and the second photosensitive element D2T are the same; Step (2): adjust the sampling value of the first photosensitive element D1T downward by U D , and will reduce U D The sampling value of the first photosensitive element D1T is compared with the sampling value of the second photosensitive element D2T; Step (3): if U is lowered D After that, the sampling value of the first photosensitive element D1T is greater than the sampling value of the second photosensitive element D2T, indicating that D1T must be touched manually. At this time, the duration t that the sampling value of D1T is higher than the sampling value of D2T is recorded within the set time T1. D If the sampling value of the first photosensitive element D1T is not greater than the sampling value of the second photosensitive element D2T, it means that there is definitely no human touch at this time, and the process returns to step (1), wherein the setting time T1 is determined according to the minimum time value required for the touch to switch the screen display mode, that is, when the screen display mode needs to be switched, the shortest time required to touch the photosensitive element D1T is determined; Step (4), determine whether the duration t is less than the set time T1. If it is less than the set time T1, switch the current display content in the current display mode to the next display content; if it is not less than the set time T1, switch the current display mode to the next display mode.

10. The method for switching the intelligent display of an instrument according to claim 9, characterized in that: U D The determination method is as follows: a. uniformly set m different light intensities, and place the two photosensitive elements D1T and D2T in the m different light intensities respectively; b. Without touching, record the n measured values ​​of the two photosensitive elements D1T and D2T at the i-th light intensity, respectively, and record them as c. Calculate the average value of n measured values ​​of D1T at the i-th light intensity and the average of n measurements of D2T at the i-th light intensity d. Calculate the n measured values ​​of D1T at the i-th light intensity and The absolute value of the difference and the n measured values ​​of D2T at the i-th light intensity and The absolute value of the difference; e. D Take 2|u| max +Δu, where |u| max is the maximum value among all absolute values, and Δu is the current conduction voltage of all diodes greater than 2|u| max And with 2|u| max The closest on-state voltage is 2|u| max The difference.

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