Light intensity detection method and light intensity detection circuit

Abstract

The present application provides a light intensity detection method and a light intensity detection circuit, which provide a first voltage between the gate and the source of a first thin film transistor that is illuminated, and provide a second voltage between the gate and the source of a second thin film transistor that is not illuminated, detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor, and determine whether the first current and the second current belong to a preset current range. A voltage adjustment operation based on an adjustment direction is used to improve the light detection accuracy. The adjustment direction includes increasing or decreasing. The first voltage and the second voltage are adjusted according to the adjustment direction to obtain a third voltage and a fourth voltage. The third current passing through the first thin film transistor and the fourth current passing through the second thin film transistor are detected. If the third current and the fourth current belong to the preset current range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current, thereby improving the light detection accuracy.

Description

Technical Field

[0001] The present application relates to the field of semiconductors, and in particular to a light intensity detection method and a light intensity detection circuit. Background Art

[0002] At present, when a thin film transistor (TFT) encounters light irradiation, its internal electron mobility changes. Under the same voltage, the current flowing through the source and drain of the TFT will change. There is a certain correlation between the light intensity and the current change. Therefore, an integrated circuit (IC) can be used to detect the current of the TFT, and then the light intensity is calculated based on the current. Commonly used IC models include ILI9881T, STK33562, etc. Among these ICs, some ICs have a large range and can measure the light intensity in a large range, but the detection accuracy is low. For example, when the illumination range is 0 to 16400 lux, the illumination detection accuracy is 3.66 lux; some ICs have high detection accuracy, but the detection range is small. For example, when the illumination range is 0 to 1300 lux, the illumination detection accuracy is 0.25 lux. In other words, these ICs cannot take into account both a large range and high accuracy at the same time, and the light intensity detection effect is poor. Summary of the invention

[0003] In view of this, the purpose of this application is to provide a light intensity detection method and a light intensity detection circuit, which can take into account both a large range and high precision, and improve the light detection accuracy. The specific scheme is as follows:

[0004] In a first aspect, the present application provides a light intensity detection method, comprising:

[0005] Providing a first voltage between a gate and a source of a first thin film transistor illuminated by light, providing a second voltage between a gate and a source of a second thin film transistor not illuminated by light, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor;

[0006] After determining that the first current and the second current belong to a preset current range, determining an adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increasing or decreasing;

[0007] The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, and a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected;

[0008] If the third current and the fourth current belong to the preset current range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current, and the fourth current.

[0009] In a second aspect, an embodiment of the present application further provides a light intensity detection circuit, comprising: a first thin film transistor, a second thin film transistor and a detection module;

[0010] The detection module is used to provide a first voltage between the gate and the source of the first thin film transistor that is illuminated, provide a second voltage between the gate and the source of the second thin film transistor that is not illuminated, and detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor; after determining that the first current and the second current belong to a preset current range, determine the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, and the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increase or decrease; adjust the first voltage and the second voltage respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, and detect and obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor; if the third current and the fourth current belong to the preset current range, determine the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.

[0011] The embodiment of the present application provides a light intensity detection method and a light intensity detection circuit, which provide a first voltage between the gate and the source of a first thin film transistor that is illuminated, provide a second voltage between the gate and the source of a second thin film transistor that is not illuminated, and detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor. Then, it is determined that the first current and the second current belong to a preset current range, so that the first current and the second current are ensured to be within an appropriate range, which can prevent the current from being too large to burn out the measuring device, and can also prevent the current from being too small to be measured. Then, according to the voltage range to which the first voltage and the second voltage belong, the adjustment direction of the first voltage and the second voltage is determined. The voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy. The adjustment direction includes increasing or decreasing. The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage. In this way, the light of the first thin film transistor can be detected at a lower accuracy first through the first voltage. The lower accuracy is accompanied by a larger range, that is, the light detection can be performed within a larger range first, and the detection accuracy can be improved and the detection range can be narrowed through voltage adjustment.

[0012] A third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected. If the third current and the fourth current belong to a preset current range, indicating that the third current and the fourth current are within an appropriate range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Since the third current and the fourth current are obtained at the third voltage and the fourth voltage respectively, and the third voltage and the fourth voltage make the light detection accuracy greater, the light intensity of the illuminated thin film transistor can be determined at a greater light detection accuracy. Compared with the detection result determined according to the first current and the second current, the detection result determined according to the third current and the fourth current is more accurate, thereby improving the light detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1-4 The current ratio provided by the embodiment of the present application varies with V gs A graph of changes;

[0015] Figure 5 A schematic diagram of a light intensity detection method provided in an embodiment of the present application is shown;

[0016] Figure 6 A structural block diagram of a light intensity detection circuit provided in an embodiment of the present application is shown;

[0017] Figure 7 A structural block diagram of another light intensity detection circuit provided in an embodiment of the present application is shown;

[0018] Figure 8 A structural block diagram of another light intensity detection circuit provided in an embodiment of the present application is shown;

[0019] Fig. 9 A structural block diagram of another light intensity detection circuit provided in an embodiment of the present application is shown;

[0020] Fig.10 A structural block diagram of another light intensity detection circuit provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0023] As described in the background technology, when a TFT encounters light, its internal electron mobility changes. At the same voltage, the current flowing through the source and drain of the TFT will change. There is a certain correlation between the light intensity and the current change. Therefore, two thin film transistors can be set, including a thin film transistor that is illuminated by light of a certain light intensity and another thin film transistor that is not illuminated. An IC can be used to provide a voltage between the source and drain of the two thin film transistors, as well as a voltage between the gate and the source, and detect the current size of the two thin film transistors. Then, the ratio of the two is calculated to obtain the current ratio. Using the corresponding relationship between the current ratio and the light intensity, the light intensity can be calculated. However, the current range that the existing IC can detect is limited. When one current scale corresponds to one light intensity, its detection of light cannot take into account both a large range and high precision at the same time. A large range can be applied to more detection scenarios, while high precision can obtain more accurate detection values. Therefore, it cannot obtain accurate detection values ​​in different detection scenarios, and the light intensity detection effect is poor, and the light detection accuracy is low.

[0024] After research, the inventors found that when the source and drain voltages of the two thin-film transistors remain unchanged, by changing the voltage between the gate and source of the two thin-film transistors, different current ratios can be obtained when the light intensity remains unchanged. The larger the current ratio, the greater the current difference between the two thin-film transistors, the more sensitive the IC is to light, and therefore the higher the light detection accuracy.

[0025] refer to Figure 1-4 As shown, the current ratio provided by the embodiment of the present application varies with V gs The horizontal axis is the voltage V between the source and gate of the thin film transistor. gs , the ordinate is the current ratio, where the light intensity is represented by 160mA (about 7500nit), the light intensity without light is recorded as 0mA, and the voltage V between the source and drain of the two thin film transistors is ds When the voltage V between the gate and source of the two thin film transistors is the same, both are 15.1V. gs At the same time, V gs When the current flowing through the two thin film transistors changes, the current flowing through the two thin film transistors will also change. Calculate the ratio of the current flowing through the two thin film transistors. Figure 1 , when V gsWhen changing between -20V and 5V, the current ratio first increases and then decreases. The current ratio range is about 0-1300. gs When the current ratio reaches a maximum value of about 1300 at V gs At -20V, the current ratio reaches a smaller value, and at V gs For 5V, the current ratio reaches another smaller value of about 9; see Figure 2 , when V gs When changing between 5V and 12V, the current ratio drops from 9 to 1.65; see Figure 3 , when V gs When changing between 12V and 25V, the current ratio drops from 1.65 to 1.19; see Figure 4 , when V gs When changing between 25V and 40V, the current ratio drops from 1.19 to 1.11. It can be found that different V gs The current ratio is different, the detection accuracy of light is different, V gs When it is around -7V, the current ratio is the largest, the sensitivity to light is the highest, and the detection accuracy of light is the highest. gs When it is greater than -7V, as V gs As the current ratio increases, V gs The larger the current ratio, the smaller and more stable it is. gs When it is less than -7V, as V gs As the current ratio decreases, V gs The smaller it is, the smaller and more stable the current ratio is, and the lower the detection accuracy of light is.

[0026] Based on the above technical problems, the embodiments of the present application provide a light intensity detection method and a light intensity detection circuit, which provide a first voltage between the gate and the source of a first thin film transistor that is illuminated, provide a second voltage between the gate and the source of a second thin film transistor that is not illuminated, and detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor. Then, it is determined that the first current and the second current belong to a preset current range, so that the first current and the second current are ensured to be within an appropriate range, which can prevent the current from being too large to burn out the measuring device, and can also prevent the current from being too small to be measured. Then, according to the voltage range to which the first voltage and the second voltage belong, the adjustment direction of the first voltage and the second voltage is determined. The voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy. The adjustment direction includes increasing or decreasing. The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage. In this way, the light of the first thin film transistor can be detected at a lower accuracy first through the first voltage. The lower accuracy is accompanied by a larger range, that is, the light detection can be performed within a larger range first, and the detection accuracy can be improved and the detection range can be narrowed through voltage adjustment.

[0027] A third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected. If the third current and the fourth current belong to a preset current range, indicating that the third current and the fourth current are within an appropriate range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Since the third current and the fourth current are obtained at the third voltage and the fourth voltage respectively, and the third voltage and the fourth voltage make the light detection accuracy greater, the light intensity of the illuminated thin film transistor can be determined at a greater light detection accuracy. Compared with the detection result determined according to the first current and the second current, the detection result determined according to the third current and the fourth current is more accurate, thereby improving the light detection accuracy.

[0028] For ease of understanding, a light intensity detection method and a light intensity detection circuit provided in an embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0029] refer to Figure 5 As shown, it is a flow chart of a light intensity detection method provided in an embodiment of the present application, and the method may include the following steps.

[0030] S101, providing a first voltage between the gate and the source of the first thin film transistor illuminated by light, providing a second voltage between the gate and the source of the second thin film transistor not illuminated by light, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor.

[0031] In an embodiment of the present application, two thin film transistors may be provided, one of which is illuminated and the other is not illuminated. To distinguish them, the two thin film transistors are respectively referred to as a first thin film transistor and a second thin film transistor. The first thin film transistor is an illuminated thin film transistor, and the second thin film transistor is a thin film transistor that is not illuminated. The thin film transistor includes a source, a drain, and a gate. Under a fixed light intensity, when the voltage between the gate and the source of the thin film transistor changes, the current flowing through the thin film transistor will also change, the current ratio will change, and the detection accuracy of the light intensity will also change.

[0032] In the embodiment of the present application, a first voltage can be provided between the gate and source of the first thin film transistor, and the current passing through the first thin film transistor is recorded as the first current. A second voltage can be provided between the gate and source of the second thin film transistor, and the current passing through the second thin film transistor is recorded as the second current. The magnitudes of the first current and the second current are detected. The second voltage can be the same as the first voltage or different. When the second voltage and the first voltage are different, the two can have a fixed difference, which can be a preset difference or a preset ratio, and the preset difference is a compensation voltage. When the first voltage is equal to the second voltage, the first current is usually greater than the second current.

[0033] The first voltage and the second voltage may be within a preset voltage range, which may be determined according to the characteristics of the thin film transistor, and is a voltage range in which the thin film transistor can work normally. Different thin film transistors may have different voltage ranges, such as [-20V, 40V], or [-30V, 10V], etc. The first thin film transistor and the second thin film transistor may have the same characteristics or similar characteristics. Within the preset voltage range, as the voltage increases, the detection accuracy will also change, for example, it may increase monotonically, or decrease monotonically, or it may increase first and then decrease. At a certain voltage value, the measurement accuracy is the highest, and the voltage values ​​at which the measurement accuracy of different thin film transistors is the highest are also different.

[0034] S102, after determining that the first current and the second current belong to a preset current range, determine the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, and the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increasing or decreasing.

[0035] In the embodiment of the present application, it can be determined that the first current and the second current belong to the preset current range, so that the first current and the second current can be ensured to be within the appropriate range, which can prevent the current from being too large to burn the measuring device, and can also prevent the current from being too small to be measured. The preset current range is related to the performance of the thin film transistor, which is the current range in which the thin film transistor can work normally, and is also related to the detection range of the IC performing current detection. As an example, the preset current range can be [40uA, 300uA].

[0036] Since the first current is the current passing through the thin film transistor illuminated by light, and the second current is the current passing through the thin film transistor not illuminated by light, the electron mobility of the thin film transistor illuminated is larger than that of the thin film transistor not illuminated. Therefore, when the first voltage and the second voltage are equal, or the first voltage and the second voltage are not much different, the first current is usually not less than the second current. It is determined that the first current and the second current belong to the preset current range. It can be determined that the first current is not greater than the maximum value of the preset current range, and the second current is not less than the minimum value of the preset current range.

[0037] Before determining that the first current and the second current belong to the preset current range, if it is determined that the first current and the second current do not belong to the preset current range, it is necessary to adjust the first voltage and the second voltage to adjust the first current and the second current so that the first current and the second current belong to the preset current range.

[0038] Specifically, if it is determined that the first current is greater than the maximum value of the preset current range, the excessive current is likely to burn out the measuring device. Since the current magnitude is proportional to the voltage magnitude, the first voltage and the second voltage can be reduced so that the first current and the second current belong to the preset current range, that is, the first current and the second current are not greater than the maximum value of the preset current range. For example, if the preset current range is [40uA, 300uA], the first current is 320uA, and the first current is greater than the maximum value of the preset current range of 300uA, then the first voltage and the second voltage can be reduced to reduce the current so that the first current and the second current are not greater than 300uA.

[0039] Specifically, if it is determined that the second current is less than the minimum value of the preset current range, and the current is too small to be detected, the first voltage and the second voltage can be increased so that the first current and the second current belong to the preset current range, that is, the first current and the second current are not less than the minimum value of the preset current range. For example, if the preset current range is [40uA, 300uA], the second current is 30uA, and the second current is less than the minimum value of the preset current range of 40uA, then the first voltage and the second voltage can be increased to increase the current so that the first current and the second current are not less than 40uA.

[0040] In actual operation, the first voltage and the second voltage can be set to any value within the preset voltage range. The first voltage and the second voltage can be a voltage when the detection accuracy is relatively small, or a voltage when the detection accuracy is relatively large. The first voltage and the second voltage can be adjusted according to the first current and the second current. For example, the preset voltage range is [-20V, 40V]. When the voltage is about -7V, the measurement accuracy is the highest. The first voltage can be a voltage corresponding to a smaller accuracy, such as -18V or 25V. The first voltage can also be a voltage corresponding to a larger accuracy, such as 5V.

[0041] In actual operation, the first voltage and the second voltage may also be the voltages when the detection accuracy is the highest. When the detection accuracy increases first and then decreases with the increase of the voltage, the first voltage and the second voltage may be a certain voltage value in the middle of the preset voltage range, and the first voltage and the second voltage may be adjusted according to the first current and the second current. For example, when the measurement accuracy is the highest when the voltage is -7V, the first voltage may be -7V, or the second voltage may be -7V, or both the first voltage and the second voltage may be -7V.

[0042] In actual operation, the first voltage and the second voltage may also be the voltages with the minimum detection accuracy. When the detection accuracy increases first and then decreases with the increase of voltage, at least one of the first voltage and the second voltage may be one of the endpoint values ​​of the preset voltage range, that is, the maximum value or the minimum value. The first voltage and the second voltage may be adjusted according to the first current and the second current. For example, when the preset voltage range is [-20V, 40V], the measurement accuracy is the lowest at the maximum voltage in the range, then the first voltage may be 40V, or the second voltage may be 40V, or both the first voltage and the second voltage may be 40V. For another example, when the preset voltage range is [-20V, 40V], the measurement accuracy is the lowest at the minimum voltage in the range, then the first voltage may be -20V, or the second voltage may be -20V, or both the first voltage and the second voltage may be -20V.

[0043] After determining that the first current and the second current belong to the preset current range, the adjustment direction of the first voltage and the second voltage is determined to be increasing or decreasing the voltage according to the voltage range to which the first voltage and the second voltage belong, thereby improving the light detection accuracy. In this way, the light of the first thin film transistor can be detected at a lower accuracy first through the first voltage, and the lower accuracy is accompanied by a larger range, that is, the light detection can be performed within a larger range first, and the detection accuracy can be improved and the detection range can be narrowed by adjusting the voltage.

[0044] Specifically, different thin film transistors may have different preset voltage ranges, and the voltages at which the measurement accuracy of different thin film transistors is maximum may also be different. Therefore, the voltage ranges when the voltage adjustment direction corresponding to different thin film transistors is increasing may also be different, and the voltage ranges when the voltage adjustment direction is decreasing may also be different.

[0045] According to the voltage range to which the first voltage and the second voltage belong, the adjustment direction of the first voltage and the second voltage is determined, which can be specifically: if the voltage range of the first voltage and the second voltage is the first voltage range, the adjustment direction of the first voltage and the second voltage is determined to be decreasing; if the voltage range of the first voltage and the second voltage is the second voltage range, the adjustment direction of the first voltage and the second voltage is determined to be increasing. The first voltage range and the second voltage range are both within the preset voltage range, and the first voltage range can be, for example, (-7, 40], and the second voltage range can be, for example, [-20, -7).

[0046] Specifically, when the voltage range of the thin film transistor is [-20V, 40V], the measurement accuracy is highest when the voltage is -7V. When the voltage is greater than -7V, as the voltage increases, the current ratio becomes smaller and more stable. When the voltage is less than -7V, as the voltage decreases, the current ratio becomes smaller and more stable, and the detection accuracy of light is lower at this time. Therefore, when the voltage range to which the first voltage belongs is (-7V, 40V), it is necessary to reduce the first voltage to improve the detection accuracy. When the voltage range to which the first voltage belongs is [-20V, -7V), it is necessary to increase the voltage to reduce the absolute value of the voltage, and reduce the detection range to improve the detection accuracy. Similarly, the second voltage is adjusted in the same way.

[0047] S103, adjusting the first voltage and the second voltage respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting and obtaining a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor.

[0048] Specifically, the voltage is increased or decreased according to the adjustment direction, and the voltage between the gate and the source of the first thin film transistor is adjusted from the first voltage to the third voltage, and the current passing through the first thin film transistor is the third current. Similarly, the voltage between the gate and the source of the second thin film transistor is adjusted from the second voltage to the fourth voltage, and the current passing through the second thin film transistor is the fourth current. In this way, the detection accuracy of the third voltage is higher than that of the first voltage, and the detection accuracy of the fourth voltage is higher than that of the second voltage. The current passing through the first thin film transistor and the second thin film transistor can be detected with higher detection accuracy, so that the current detection result is more accurate.

[0049] The first voltage and the second voltage are adjusted according to the adjustment direction to obtain the third voltage and the fourth voltage. Specifically, the first adjustment step of the first voltage and the second adjustment step corresponding to the second voltage are determined according to the comparison result of the first current and the second current with the preset current threshold, and the first voltage and the second voltage are adjusted to the third voltage and the fourth voltage according to the adjustment direction, the first adjustment step and the second adjustment step. In this way, the first adjustment step and the second adjustment step are determined according to the difference between the first current and the preset current threshold, and the difference between the second current and the preset current threshold, so that the first voltage is adjusted to the third voltage according to the first adjustment step, and the second voltage is adjusted to the fourth voltage according to the second adjustment step.

[0050] The difference between the first voltage and the second voltage may be the same as the difference between the third voltage and the fourth voltage, so the first adjustment step and the second adjustment step are equal, and the voltage difference only needs to be calculated once to obtain the first adjustment step and the second adjustment step, thereby simplifying the processing process.

[0051] When the first voltage is adjusted to the third voltage and the second voltage is adjusted to the fourth voltage, the third voltage and the fourth voltage can be obtained after one adjustment. In order to achieve higher precision measurement, the adjustment step value of the first voltage and the second voltage can be larger. When the first voltage is adjusted to the third voltage and the second voltage is adjusted to the fourth voltage, the third voltage and the fourth voltage can be obtained after multiple adjustments. In order to achieve higher precision measurement, the adjustment step value of the first voltage and the second voltage can be smaller.

[0052] Before determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current, the third voltage and the fourth voltage can be adjusted to the fifth voltage and the sixth voltage respectively through one adjustment according to the adjustment direction, the first adjustment step and the second adjustment step, and the fifth current passing through the first thin film transistor and the sixth current passing through the second thin film transistor can be detected, and then it is determined whether the fifth current and the sixth current exceed the preset current range.

[0053] If the fifth current and the sixth current do not exceed the preset current range, it means that the detection range can be further reduced to improve the detection accuracy, and the voltage between the gate and the source of the thin film transistor can be continuously changed until the current flowing through the thin film transistor exceeds the preset current range. Of course, it can also be considered that the fifth voltage and the sixth voltage can improve the detection accuracy, and the light intensity of the first thin film transistor can be calculated based on the fifth voltage, the sixth voltage, the fifth current and the sixth current. The calculation method of the light intensity can refer to S104.

[0054] If at least one of the fifth current and the sixth current exceeds the preset current range, it means that the fifth voltage and the sixth voltage exceed the reasonable range, and the detection accuracy has reached the maximum under the third voltage and the fourth voltage, then the operation of determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current is executed.

[0055] S104, if the third current and the fourth current belong to the preset current range, determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.

[0056] Specifically, if the third current and the fourth current belong to the preset current range, indicating that the third current and the fourth current are within the appropriate range, the illumination intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Since the third current and the fourth current are obtained at the third voltage and the fourth voltage respectively, and the third voltage and the fourth voltage make the illumination detection accuracy greater, the illumination intensity of the illuminated thin film transistor can be determined at a greater illumination detection accuracy. Compared with the detection result determined according to the first current and the second current, the detection result determined according to the third current and the fourth current is more accurate, thereby improving the illumination detection accuracy. In other words, in the embodiment of the present application, the range and accuracy of the illumination detection can be adjusted according to the detected current, so as to detect the illumination with the appropriate range and accuracy. The appropriate range can make it applicable to more detection scenarios, and the appropriate accuracy can make the detection result more accurate.

[0057] In the embodiment of the present application, the same voltage can be applied between the gate and the source of the first thin film transistor and between the gate and the source of the second thin film transistor, that is, the first voltage is equal to the second voltage, and the third voltage is equal to the fourth voltage. Then, the third current is the current passing through the thin film transistor illuminated at the third voltage, and the fourth current is the current passing through the thin film transistor not illuminated at the third voltage. The difference between the third current and the fourth current is only whether the thin film transistor is illuminated.

[0058] The light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Specifically, the ratio of the third current to the fourth current is taken as the actual current ratio, and according to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

[0059] Specifically, the third current and the fourth current measured at the same voltage are compared to obtain the actual current ratio, which is simple to calculate and simplifies the process. Then, according to the known corresponding relationship, the light intensity corresponding to the actual current ratio is found at the third voltage to obtain the light intensity of the first thin film transistor. The corresponding relationship can be some discrete points or a function analytical equation.

[0060] In the embodiment of the present application, different voltages can also be applied between the gate and the source of the first thin film transistor, and between the gate and the source of the second thin film transistor, and there is a differential voltage between the two, that is, the difference between the first voltage and the second voltage is the differential voltage, the difference between the third voltage and the fourth voltage is the differential voltage, the difference between the first voltage and the second voltage is the same as the difference between the third voltage and the fourth voltage, and the differential voltage can be determined based on at least one of the temperature characteristic difference and the process characteristic difference between the first thin film transistor and the second thin film transistor.

[0061] The light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Specifically, the fourth current is numerically corrected according to the third voltage and the fourth voltage to obtain a reference current, and the ratio of the third current to the reference current is used as the actual current ratio. According to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

[0062] Among them, since the voltages corresponding to the third current and the fourth current are different and under different conditions, it is impossible to calculate the actual current ratio to characterize the light intensity. It is necessary to correct the fourth current according to the corresponding relationship between the voltage and the current to obtain the reference current corresponding to the third voltage, so that the reference current and the third current are at the same voltage, so as to calculate the actual current ratio and thus characterize the light intensity. In addition, by applying different voltages to the first thin film transistor and the second thin film transistor, the independence of the first thin film transistor and the second thin film transistor can be increased, and they do not interfere with each other, which can increase the flexibility of voltage adjustment.

[0063] The embodiment of the present application provides a light intensity detection method, which provides a first voltage between the gate and the source of a first thin film transistor that is illuminated, provides a second voltage between the gate and the source of a second thin film transistor that is not illuminated, and detects a first current passing through the first thin film transistor and a second current passing through the second thin film transistor. Then, it is determined that the first current and the second current belong to a preset current range, so that the first current and the second current are ensured to be within an appropriate range, which can prevent the current from being too large to burn out the measuring device, and can also prevent the current from being too small to be measured. Then, according to the voltage range to which the first voltage and the second voltage belong, the adjustment direction of the first voltage and the second voltage is determined. The voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy. The adjustment direction includes increasing or decreasing. The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage. In this way, the light of the first thin film transistor can be detected at a lower accuracy first through the first voltage. The lower accuracy is accompanied by a larger range, that is, the light detection can be performed within a larger range first, and the detection accuracy can be improved and the detection range can be narrowed through voltage adjustment.

[0064] A third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected. If the third current and the fourth current belong to a preset current range, indicating that the third current and the fourth current are within an appropriate range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Since the third current and the fourth current are obtained at the third voltage and the fourth voltage respectively, and the third voltage and the fourth voltage make the light detection accuracy greater, the light intensity of the illuminated thin film transistor can be determined at a greater light detection accuracy. Compared with the detection result determined according to the first current and the second current, the detection result determined according to the third current and the fourth current is more accurate, thereby improving the light detection accuracy.

[0065] Based on the above light intensity detection method, the present application embodiment also provides a light intensity detection circuit, referring to Figure 6 As shown, it is a structural block diagram of a light intensity detection circuit provided in an embodiment of the present application. The light intensity detection circuit may include a first thin film transistor 100, a second thin film transistor 200 and a detection module 300. The first thin film transistor 100 is a thin film transistor illuminated by light, and the second thin film transistor 200 is a thin film transistor not illuminated by light. When light irradiates the first thin film transistor 100, the current passing through the first thin film transistor 100 will change compared to the second thin film transistor 200. The detection module may be an IC circuit.

[0066] The detection module 300 is used to provide a first voltage between the gate and the source of the first thin film transistor 100 that is illuminated, provide a second voltage between the gate and the source of the second thin film transistor 200 that is not illuminated, and detect a first current passing through the first thin film transistor 100 and a second current passing through the second thin film transistor 200; after determining that the first current and the second current belong to a preset current range, determine the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, and the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increasing or decreasing; adjust the first voltage and the second voltage according to the adjustment direction respectively to obtain a third voltage and a fourth voltage, and detect and obtain a third current passing through the first thin film transistor 100 and a fourth current passing through the second thin film transistor 200; if the third current and the fourth current belong to the preset current range, determine the light intensity of the first thin film transistor 100 according to the third voltage, the fourth voltage, the third current and the fourth current.

[0067] In the embodiment of the present application, the first voltage may be equal to the second voltage, the third voltage may be equal to the fourth voltage, and the reference voltage may be equal to the fourth voltage. Figure 7 As shown, it is a structural block diagram of another light intensity detection circuit provided in an embodiment of the present application. The first thin film transistor 100 and the second thin film transistor 200 are connected in parallel and connected to the detection module 300. The first end of the detection module 300 is connected to the gate of the first thin film transistor 100 and the gate of the second thin film transistor 200 at the same time, so that the first voltage can be equal to the second voltage, and the third voltage can be equal to the fourth voltage. The second end of the detection module 300 is connected to the source of the first thin film transistor 100 and the source of the second thin film transistor 200. The third end of the detection module 300 is connected to the drain of the first thin film transistor 100 for detecting the current passing through the first thin film transistor 100. The fourth end of the detection module 300 is connected to the drain of the second thin film transistor 200 for detecting the current passing through the second thin film transistor 200. By controlling the voltage between the gate and the source of the thin film transistor, the current passing through the thin film transistor can be controlled.

[0068] The light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current, which can be specifically:

[0069] taking the ratio of the third current to the fourth current as the actual current ratio;

[0070] According to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

[0071] In the embodiment of the present application, the light intensity detection circuit further includes a first voltage compensation module 400, which is used to compensate the voltage output by the detection module to obtain the first voltage and the third voltage, or to obtain the second voltage and the fourth voltage. Figure 8 As shown, it is a structural block diagram of another light intensity detection circuit provided in an embodiment of the present application, including a first thin film transistor 100, a second thin film transistor 200, a detection module 300 and a first voltage compensation module 400. The detection module 300 provides a voltage to the gate of the first thin film transistor 100 and the gate of the second thin film transistor 200 through the first voltage compensation module 400. The first voltage compensation module 400 can adjust the voltage transmitted to the gate of the first thin film transistor 100 and the gate of the second thin film transistor 200 according to the voltage provided by the detection module 300, so as to control the voltage applied to the first thin film transistor 100 and the second thin film transistor 200.

[0072] In the embodiment of the present application, the light intensity detection circuit further includes a second voltage compensation module 500 and a third voltage compensation module 600;

[0073] The second voltage compensation module 500 is used to compensate the voltage output by the detection module to obtain the first voltage or the third voltage; the second voltage compensation module generates the first compensation voltage;

[0074] The third voltage compensation module 600 is used to compensate the voltage output by the detection module to obtain a second voltage or a fourth voltage; the third voltage compensation module generates a second compensation voltage;

[0075] The difference between the first compensation voltage and the second compensation voltage is used as the difference voltage, the difference between the first voltage and the second voltage is the difference voltage, the difference between the third voltage and the fourth voltage is the difference voltage, and the difference voltage is determined according to at least one of the temperature characteristic difference and the process characteristic difference between the first thin film transistor and the second thin film transistor. Fig. 9 As shown, it is a structural block diagram of another light intensity detection circuit provided in an embodiment of the present application, including a first thin film transistor 100, a second thin film transistor 200, a detection module 300, a second voltage compensation module 500 and a third voltage compensation module 600. The detection module provides a voltage to the gate of the first thin film transistor through the second voltage compensation module, and provides a voltage to the gate of the second thin film transistor through the third voltage compensation module. The second voltage compensation module and the third voltage compensation module can respectively adjust the voltage transmitted to the gate of the first thin film transistor and the gate of the second thin film transistor according to the voltage provided by the detection module.

[0076] In the embodiment of the present application, the second voltage compensation module and the third voltage compensation module may be passive circuits or active circuits. When they are passive circuits, the detection module may supply power to the second voltage compensation module and the third voltage compensation module. Fig.10As shown, it is a structural block diagram of another light intensity detection circuit provided in an embodiment of the present application, in which the second voltage compensation module and the third voltage compensation module are respectively connected to the fifth end and the sixth end of the detection module, so that the detection module can supply power to the second voltage compensation module and the third voltage compensation module.

[0077] The embodiment of the present application provides a light intensity detection circuit, including a first thin film transistor, a second thin film transistor and a detection module, the detection module is used to provide a first voltage between the gate and the source of the first thin film transistor that is illuminated, provide a second voltage between the gate and the source of the second thin film transistor that is not illuminated, and detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor, and then determine that the first current and the second current belong to a preset current range, so as to ensure that the first current and the second current are within a suitable range, which can prevent the current from being too large to burn out the measuring device, and can also prevent the current from being too small to be measured, and then determine the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, and the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, the adjustment direction includes increasing or decreasing, and the first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, so that the light of the first thin film transistor can be detected at a lower accuracy first through the first voltage, and the lower accuracy is accompanied by a larger range, that is, the light detection can be performed within a larger range first, and the detection accuracy can be improved and the detection range can be narrowed through voltage adjustment.

[0078] A third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected. If the third current and the fourth current belong to a preset current range, indicating that the third current and the fourth current are within an appropriate range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current. Since the third current and the fourth current are obtained at the third voltage and the fourth voltage respectively, and the third voltage and the fourth voltage make the light detection accuracy greater, the light intensity of the illuminated thin film transistor can be determined at a greater light detection accuracy. Compared with the detection result determined according to the first current and the second current, the detection result determined according to the third current and the fourth current is more accurate, thereby improving the light detection accuracy.

[0079] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the detection circuit embodiment, since it is basically similar to the detection method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0080] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A light intensity detection method, characterized in that: The method comprises: Providing a first voltage between a gate and a source of a first thin film transistor illuminated by light, providing a second voltage between a gate and a source of a second thin film transistor not illuminated by light, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor; After determining that the first current and the second current belong to a preset current range, determining the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increasing or decreasing; the current ratio of the first thin film transistor illuminated by light and the second thin film transistor not illuminated by light has a changing relationship with the voltage between the gate and the source under the condition of equal voltage between the gate and the source, and the adjustment direction is determined according to the changing relationship; The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, and a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected; If the third current and the fourth current belong to the preset current range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current, and the fourth current.

2. The method according to claim 1, characterized in that The first voltage is equal to the second voltage, the third voltage is equal to the fourth voltage, and determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current, and the fourth current includes: taking a ratio of the third current to the fourth current as an actual current ratio; According to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

3. The method according to claim 1, characterized in that: The difference between the first voltage and the second voltage is used as a difference voltage, the difference between the third voltage and the fourth voltage is the difference voltage, and the difference voltage is determined according to at least one of a temperature characteristic difference and a process characteristic difference between the first thin film transistor and the second thin film transistor; The step of determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current comprises: According to the third voltage and the fourth voltage, performing numerical correction on the fourth current to obtain a reference current; taking the ratio of the third current to the reference current as the actual current ratio; According to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

4. The method according to any one of claims 1 to 3, characterized in that: The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, including: Determine a first adjustment step size of the first voltage and a second adjustment step size corresponding to the second voltage respectively according to a comparison result of the first current and the second current with a preset current threshold; According to the adjustment direction, the first adjustment step size, and the second adjustment step size, the first voltage and the second voltage are adjusted to the third voltage and the fourth voltage respectively.

5. The method according to claim 4, characterized in that A difference between the first voltage and the second voltage is the same as a difference between the third voltage and the fourth voltage, and the first adjustment step size is equal to the second adjustment step size.

6. The method according to claim 4, characterized in that Before determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current, the method further includes: According to the adjustment direction, the first adjustment step length and the second adjustment step length, the third voltage and the fourth voltage are adjusted to a fifth voltage and a sixth voltage respectively, and a fifth current passing through the first thin film transistor and a sixth current passing through the second thin film transistor are detected; If at least one of the fifth current and the sixth current exceeds the preset current range, the operation of determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current is performed.

7. The method according to any one of claims 1 to 3, characterized in that: The determining, according to the voltage ranges to which the first voltage and the second voltage belong, the adjustment directions of the first voltage and the second voltage includes: If the voltage range of the first voltage and the second voltage is (-7, 40], it is determined that the adjustment direction of the first voltage and the second voltage is to decrease; If the voltage range of the first voltage and the second voltage is [-20, -7), it is determined that the adjustment direction of the first voltage and the second voltage is increasing.

8. The method according to any one of claims 1 to 3, characterized in that: Before determining that the first current and the second current belong to a preset current range, the method further includes: If it is determined that the first current is greater than the maximum value of the preset current range, reducing the first voltage and the second voltage so that the first current and the second current belong to the preset current range; If it is determined that the second current is less than the minimum value of the preset current range, the first voltage and the second voltage are increased so that the first current and the second current belong to the preset current range.

9. The method according to claim 8, characterized in that The first voltage and the second voltage belong to a preset voltage range, at least one of the first voltage and the second voltage is a maximum value in the preset voltage range, or at least one of the first voltage and the second voltage is a minimum value in the preset voltage range.

10. A light intensity detection circuit, characterized in that: include: A first thin film transistor, a second thin film transistor and a detection module; The detection module is used to provide a first voltage between the gate and the source of the first thin film transistor illuminated by light, provide a second voltage between the gate and the source of the second thin film transistor not illuminated by light, and detect a first current passing through the first thin film transistor and a second current passing through the second thin film transistor; After determining that the first current and the second current belong to a preset current range, determining the adjustment direction of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, the voltage adjustment operation based on the adjustment direction is used to improve the light detection accuracy, and the adjustment direction includes increasing or decreasing; the current ratio of the first thin film transistor illuminated by light and the second thin film transistor not illuminated by light has a changing relationship with the voltage between the gate and the source under the condition of equal voltage between the gate and the source, and the adjustment direction is determined according to the changing relationship; The first voltage and the second voltage are adjusted respectively according to the adjustment direction to obtain a third voltage and a fourth voltage, and a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected; if the third current and the fourth current belong to the preset current range, the light intensity of the first thin film transistor is determined according to the third voltage, the fourth voltage, the third current and the fourth current.

11. The light intensity detection circuit according to claim 10, characterized in that: The first voltage is equal to the second voltage, the third voltage is equal to the fourth voltage, and determining the light intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current, and the fourth current includes: taking a ratio of the third current to the fourth current as an actual current ratio; According to the corresponding relationship between the current ratio and the light intensity under the third voltage, the light intensity corresponding to the actual current ratio is determined as the light intensity of the first thin film transistor.

12. The light intensity detection circuit according to claim 11, characterized in that: The light intensity detection circuit further includes a first voltage compensation module, which is used to compensate the voltage output by the detection module to obtain the first voltage and the third voltage, or to obtain the second voltage and the fourth voltage.

13. The light intensity detection circuit according to claim 10, characterized in that: The light intensity detection circuit also includes a second voltage compensation module and a third voltage compensation module; The second voltage compensation module is used to compensate the voltage output by the detection module to obtain the first voltage or the third voltage; The second voltage compensation module generates a first compensation voltage; The third voltage compensation module is used to compensate the voltage output by the detection module to obtain the second voltage or the fourth voltage; The third voltage compensation module generates a second compensation voltage; The difference between the first compensation voltage and the second compensation voltage is used as a difference voltage, the difference between the first voltage and the second voltage is the difference voltage, the difference between the third voltage and the fourth voltage is the difference voltage, and the difference voltage is determined based on at least one of a temperature characteristic difference and a process characteristic difference between the first thin film transistor and the second thin film transistor.

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