CN115265774A - Light intensity detection method and light intensity detection circuit - Google Patents

Light intensity detection method and light intensity detection circuit Download PDF

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Publication number
CN115265774A
CN115265774A CN202210907217.5A CN202210907217A CN115265774A CN 115265774 A CN115265774 A CN 115265774A CN 202210907217 A CN202210907217 A CN 202210907217A CN 115265774 A CN115265774 A CN 115265774A
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voltage
current
thin film
film transistor
range
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金慧俊
董良
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Shanghai AVIC Optoelectronics Co Ltd
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Shanghai AVIC Optoelectronics Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J2001/4446—Type of detector
    • G01J2001/4473—Phototransistor

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  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

The application provides a light intensity detection method and a light intensity detection circuit, a first voltage is provided between a grid electrode and a source electrode of a first thin film transistor which is illuminated, a second voltage is provided between a grid electrode and a source electrode of a second thin film transistor which is not illuminated, a first current passing through the first thin film transistor is detected, a second current passing through the second thin film transistor is determined, the first current and the second current belong to a preset current range, voltage adjustment operation based on an adjustment direction is used for improving illumination detection precision, the adjustment direction comprises increasing or decreasing, the first voltage and the second voltage are respectively adjusted according to the adjustment direction to obtain a third voltage and a fourth voltage, a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor are detected, and if the third current and the fourth current belong to the preset current 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, and the illumination detection precision is improved.

Description

Light intensity detection method and light intensity detection circuit
Technical Field
The present disclosure relates to the field of semiconductors, and more particularly, to a light intensity detection method and a light intensity detection circuit.
Background
At present, when a Thin Film Transistor (TFT) is irradiated by light, the mobility of electrons inside the TFT changes, the magnitude of current flowing through a source electrode and a drain electrode of the TFT changes under the same voltage, and the intensity of the light irradiation has a certain relationship with the change of the current, so that an Integrated Circuit (IC) can be used to detect the magnitude of the current of the TFT, and then the magnitude of the light intensity can be calculated according to the magnitude of the current. Common types of ICs include ILI9881T, STK33562, and the like, some of these ICs have a large range, and can measure the light intensity in a large range, however, the detection accuracy is low, for example, when the illumination range is 0 to 16400lux, the illumination detection accuracy is 3.66lux; some ICs have higher detection accuracy, but the detection range is smaller, for example, when the illumination range is 0 to 1300lux, the detection accuracy of the illumination is 0.25lux, that is, none of these ICs can simultaneously achieve both large range and high accuracy, and the detection effect on the illumination intensity is poor.
Disclosure of Invention
In view of this, an object of the present application is to provide a light intensity detection method and a light intensity detection circuit, which can simultaneously consider a large range and high precision, and improve illumination detection precision. The specific scheme is as follows:
in a first aspect, the present application provides a light intensity detecting method, including:
providing a first voltage between a gate and a source of a first thin film transistor which is illuminated, providing a second voltage between a gate and a source of a second thin film transistor which is not illuminated, and detecting a first current through the first thin film transistor and a second current through the second thin film transistor;
after the first current and the second current are determined to belong to a preset current range, according to voltage ranges to which the first voltage and the second voltage belong, determining adjustment directions of the first voltage and the second voltage, wherein voltage adjustment operation based on the adjustment directions is used for improving illumination detection precision, and the adjustment directions comprise increasing or decreasing;
respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor;
and if the third current and the fourth current belong to the preset current range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current.
In a second aspect, an embodiment of the present application further provides a light intensity detecting circuit, including: the device comprises a first thin film transistor, a second thin film transistor and a detection module;
the detection module is used for providing a first voltage between a grid electrode and a source electrode of a first thin film transistor which is illuminated, providing a second voltage between a grid electrode and a source electrode of a second thin film transistor which is not illuminated, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor; after the first current and the second current are determined to belong to a preset current range, according to the voltage ranges to which the first voltage and the second voltage belong, determining adjustment directions of the first voltage and the second voltage, wherein voltage adjustment operation based on the adjustment directions is used for improving illumination detection precision, and the adjustment directions comprise increasing or decreasing; respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor; and if the third current and the fourth current belong to the preset current range, determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.
The embodiment of the application provides a light intensity detection method and a light intensity detection circuit, a first voltage is provided between a grid electrode and a source electrode of a first thin film transistor which is illuminated, a second voltage is provided between a grid electrode and a source electrode of a second thin film transistor which is not illuminated, a first current passing through the first thin film transistor and a second current passing through the second thin film transistor are detected, then the first current and the second current are determined to belong to a preset current range, the first current and the second current are ensured to be in a proper range, not only can the measuring equipment be prevented from being burnt out by too much current, but also the current can be prevented from being too small and incapable of being measured, then adjustment directions of the first voltage and the second voltage are determined according to the voltage range to which the first voltage and the second voltage belong, voltage adjustment operation based on the adjustment directions is used for improving illumination detection accuracy, the adjustment directions include increasing or decreasing, the first voltage and the second voltage are respectively adjusted according to the adjustment directions, a third voltage and a fourth voltage are obtained, so that the first voltage can be used for enabling the first thin film transistor to be smaller, the illumination detection accuracy can be reduced in a larger range, and the illumination accuracy can be improved in a detection range can be detected, and the illumination accuracy can be improved.
The method comprises the steps of detecting to obtain a third current passing through a first thin film transistor and a fourth current passing through a second thin film transistor, if the third current and the fourth current belong to a preset current range, and the third current and the fourth current are in a proper range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current, wherein the third current and the fourth current are respectively obtained under the third voltage and the fourth voltage, and the third voltage and the fourth voltage enable the illumination detection precision to be larger, so that the illumination intensity of the illuminated thin film transistor can be determined under the larger illumination detection precision.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIGS. 1-4 show the ratio of current provided by an embodiment of the present application as a function of VgsA graph of the variation;
FIG. 5 is a flow chart illustrating a method for detecting light intensity according to an embodiment of the present disclosure;
fig. 6 is a block diagram illustrating a structure of a light intensity detection circuit according to an embodiment of the present application;
FIG. 7 is a block diagram illustrating a structure of another light intensity detecting circuit provided in an embodiment of the present application;
FIG. 8 is a block diagram illustrating a structure of another light intensity detecting circuit provided in an embodiment of the present application;
FIG. 9 is a block diagram illustrating a structure of another light intensity detecting circuit provided in an embodiment of the present application;
fig. 10 shows a block diagram of a structure of another light intensity detection circuit provided in an embodiment of the present application.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying figures are described in detail below.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and it will be apparent to those of ordinary skill in the art that the present application is not limited by the specific embodiments disclosed below.
As described in the background art, when the TFT is exposed to light, the mobility of electrons inside the TFT changes, the magnitude of current flowing through the source and the drain of the TFT changes under the same voltage, and the light intensity and the current change have a certain relationship, so that two thin film transistors including a thin film transistor irradiated with light of a certain light intensity and another thin film transistor not irradiated with light can be provided. However, the current range that can be detected by the existing IC is limited, and under the condition that one current scale corresponds to one illumination intensity, the illumination detection cannot simultaneously take into account the wide range and the high precision, the wide range can be applicable to more detection scenes, and the high precision can obtain a more accurate detection value, so that the detection cannot obtain an accurate detection value under different detection scenes, the illumination intensity detection effect is poor, and the illumination detection precision is low.
The inventor researches and discovers that under the condition that the source electrode voltage and the drain electrode voltage of the two thin film transistors are not changed, the voltages between the grid electrodes and the source electrodes of the two thin film transistors are changed, different current ratios are obtained under the condition that light irradiation is not changed, and the larger the current ratio is, the larger the current difference of the two thin film transistors is, the more sensitive the IC is to the light irradiation, and therefore, the higher the detection accuracy of the light irradiation is.
Referring to FIGS. 1-4, the current ratios provided for the examples of the present application are shown as VgsGraph of variation with abscissa of voltage V between source and gate of thin film transistorgsThe ordinate is a current ratio in which the intensity of light irradiation is represented by 160mA (about 7500 nit), the intensity of light irradiation without light irradiation is noted as 0mA, and a voltage V between the source and drain electrodes of the two thin film transistorsdsWhen the voltage V is equal to 15.1V, the voltage V between the grid electrode and the source electrode of the two thin film transistors is controlledgsWhile varying between-20V and 40V, VgsWhen the current flowing through the two thin film transistors changes, the ratio of the current flowing through the two thin film transistors is calculated. Referring to FIG. 1, when VgsWhen the current ratio is changed between-20V and 5V, the current ratio is firstly increased and then decreased, the current ratio is in the range of about 0-1300, and the current ratio is in VgsAt around-7V, the current ratio reaches a maximum of about 1300 at Vgsat-20V, the current ratio reaches a small value, and at VgsAt 5V, the current ratio reaches another smaller value of about 9; see FIG. 2, when VgsThe current ratio decreased from 9 to 1.65 when varied between 5V and 12V; see FIG. 3, when VgsThe current ratio dropped from 1.65 to 1.19 when varied between 12V and 25V; referring to FIG. 4, when VgsThe current ratio dropped from 1.19 to 1.11 when varied between 25V and 40V. It can be found that different VgsDifferent lower current ratios, different detection accuracy of illumination, VgsThe current ratio is maximum when the voltage is about-7V, the sensitivity to illumination is highest at the moment, the detection precision to illumination is highest, and the voltage is Vgsabove-7V, with VgsIncrease of current ratio byDecreasing, VgsThe larger the current ratio, the more stable the current ratio, at VgsLess than-7V, with VgsDecrease of (2), current ratio decrease gradually, VgsThe smaller the current ratio, the more stable the current ratio, and the lower the detection accuracy of light irradiation.
Based on the above technical problem, an embodiment of the present invention provides a light intensity detection method and a light intensity detection circuit, which provide a first voltage between a gate and a source of a first thin film transistor that is illuminated, provide a second voltage between a gate and a 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 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 proper range, thereby preventing the current from burning out a measurement device due to too large current and preventing the current from being too small to be measured, and then determine adjustment directions of the first voltage and the second voltage according to the voltage range to which the first voltage and the second voltage belong, wherein the adjustment operation is based on the adjustment direction is used to improve the illumination detection accuracy, the adjustment direction includes increasing or decreasing, and the first voltage and the second voltage are respectively adjusted according to the adjustment directions to obtain a third voltage and a fourth voltage, so that the illumination detection accuracy can be reduced in a larger range by the first thin film transistor, and the illumination detection accuracy can be reduced in a smaller range, thereby enabling the illumination detection accuracy to be detected in a smaller range.
The method comprises the steps of detecting to obtain a third current passing through a first thin film transistor and a fourth current passing through a second thin film transistor, if the third current and the fourth current belong to a preset current range, and the third current and the fourth current are in a proper range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current, wherein the third current and the fourth current are respectively obtained under the third voltage and the fourth voltage, and the third voltage and the fourth voltage enable the illumination detection precision to be larger, so that the illumination intensity of the illuminated thin film transistor can be determined under the larger illumination detection precision.
For convenience of understanding, the following describes a light intensity detection method and a light intensity detection circuit provided in the embodiments of the present application in detail with reference to the drawings.
Referring to fig. 5, a schematic flow chart of a light intensity detection method provided in an embodiment of the present application is shown, where the method may include the following steps.
And S101, providing a first voltage between a grid electrode and a source electrode of the first thin film transistor which is illuminated, providing a second voltage between a grid electrode and a source electrode of the second thin film transistor which is not illuminated, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor.
In this embodiment, two thin film transistors may be provided, one of the two thin film transistors is illuminated, and the other is not illuminated, for the purpose of distinguishing, the two thin film transistors are respectively denoted as a first thin film transistor and a second thin film transistor, the first thin film transistor is an illuminated thin film transistor, the second thin film transistor is an un-illuminated thin film transistor, the thin film transistors include a source, a drain, and a gate, and when a voltage between the gate and the source of the thin film transistor changes under a fixed illumination intensity, a current flowing through the thin film transistor also changes, a current ratio changes, and a detection accuracy of the illumination intensity also changes.
In this embodiment, a first voltage may be provided between a gate and a source of a first thin film transistor, a current passing through the first thin film transistor is recorded as a first current, a second voltage is provided between a gate and a source of a second thin film transistor, a current passing through the second thin film transistor is recorded as a second current, and sizes of the first current and the second current are detected. The first current is generally greater than the second current when the first voltage is equal to the second voltage.
The first voltage and the second voltage may be within a predetermined voltage range, the predetermined voltage range may be determined according to characteristics of the thin film transistor, and for the voltage range in which the thin film transistor can normally operate, different thin film transistors may have different voltage ranges, such as [ -20v,40v ], may also be [ -30v,10v ], and the like, and the first thin film transistor and the second thin film transistor may have the same characteristics or may have similar characteristics. In the preset voltage range, the detection accuracy also changes with the increase of the voltage, for example, the detection accuracy may be monotonically increased or monotonically decreased, or may be increased first and then decreased, and under a certain voltage value, the measurement accuracy is the greatest, and the voltage values at which the measurement accuracy of different thin film transistors is greatest are also different.
And S102, after the first current and the second current are determined to belong to the preset current range, determining the adjustment directions of the first voltage and the second voltage according to the voltage ranges to which the first voltage and the second voltage belong, and performing voltage adjustment operation based on the adjustment directions to improve the illumination detection precision, wherein the adjustment directions comprise increasing or decreasing.
In the embodiment of the application, the first current and the second current can be determined to belong to the preset current range, so that the first current and the second current can be ensured to be in a proper range, the measuring equipment can be prevented from being burnt out by too large current, and the current can be prevented from being too small to be measured. The preset current range is related to the performance of the thin film transistor, is a current range in which the thin film transistor can normally operate, and is also related to a detection range of an IC performing current detection, and as an example, the preset current range may be [40ua,300ua ].
Since the first current is a current passing through the illuminated thin film transistor, and the second current is a current passing through the non-illuminated thin film transistor, compared with the non-illuminated thin film transistor, the mobility of electrons of the illuminated thin film transistor is higher, so that when the first voltage and the second voltage are equal, or the difference between the first voltage and the second voltage is not large, the first current is usually not less than the second current, and the first current and the second current are determined to belong to a preset current range, the first current may be determined to be 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.
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, the first voltage and the second voltage need to be adjusted to adjust the first current and the second current, so that the first current and the second current belong to the preset current range.
Specifically, if it is determined that the first current is greater than the maximum value of the preset current range, the current is too large, which may easily burn out the measurement device, and since the current magnitude is in direct proportion to the voltage magnitude, the first voltage and the second voltage may 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 predetermined current range is [40ua,300ua ], the first current is 320uA, and the first current is greater than the maximum value 300uA of the predetermined current range, the first voltage and the second voltage may be reduced to reduce the current, so that the first current and the second current are not greater than 300uA.
Specifically, if it is determined that the second current is smaller 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 may 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 smaller 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 smaller than the minimum value 40uA of the preset current range, the first voltage and the second voltage may be increased to increase the current, so that the first current and the second current are not smaller than 40uA.
In actual operation, the first voltage and the second voltage may be set to be values at will within a preset voltage range, the first voltage and the second voltage may be voltages with lower detection accuracy or voltages with higher detection accuracy, and the first voltage and the second voltage may be adjusted subsequently according to the first current and the second current. For example, the preset voltage range is [ -20v,40v ], and when the voltage is about-7V, the measurement accuracy is the highest, the first voltage may be a voltage corresponding to a smaller accuracy, the first voltage may be-18V or 25V, and the first voltage may also be a voltage corresponding to a larger accuracy, and may be 5V.
In actual operation, the first voltage and the second voltage may also be voltages with the highest detection accuracy, and when the detection accuracy increases with the increase of the voltages, the first voltage and the second voltage may be a certain voltage value in the middle of a 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 voltage is-7V, the measurement accuracy is the maximum, the first voltage may be-7V, the second voltage may be-7V, or both the first voltage and the second voltage may be-7V.
In practical operation, the first voltage and the second voltage may also be voltages with the minimum detection accuracy, when the detection accuracy increases with the increase of the voltages and then decreases, at least one of the first voltage and the second voltage may be one endpoint of a preset voltage range, that is, a maximum value or a minimum value, and then the first voltage and the second voltage may be adjusted according to the first current and the second current. For example, when the predetermined voltage range is [ -20v,40v ], the measurement accuracy is minimum at the maximum voltage of the range, 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 predetermined voltage range is [ -20v,40v ], the measurement accuracy is minimum at the minimum voltage of the range, and 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.
After the first current and the second current are determined to belong to the preset current range, whether the adjustment directions of the first voltage and the second voltage are increased or decreased is determined according to the voltage ranges to which the first voltage and the second voltage belong, and therefore the illumination detection precision is improved. Thus, the illumination of the first thin film transistor can be detected with small precision at first through the first voltage, the illumination detection can be carried out in a large range along with the small precision along with the large range, and the detection range can be reduced by improving the detection precision through the voltage adjustment.
Specifically, different thin film transistors may have different preset voltage ranges, and the voltages of the different thin film transistors at the time of the maximum measurement accuracy may also be different, so that the voltage ranges of the different thin film transistors at the time of the adjustment direction of the voltages being increased may also be different, and the voltage ranges of the different thin film transistors at the time of the adjustment direction of the voltages being decreased may also be different.
Determining the adjustment directions of the first voltage and the second voltage according to the voltage ranges to which the first voltage and the second voltage belong, which may specifically be: if the voltage range of the first voltage and the second voltage is the first voltage range, determining that the adjustment directions of the first voltage and the second voltage are reduced; and if the voltage range of the first voltage and the second voltage is the second voltage range, determining that the adjustment directions of the first voltage and the second voltage are increased. The first voltage range, which may be (-7,40), and the second voltage range, which may be [ -20, -7), may be within the predetermined voltage range.
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 larger than-7V, the current ratio is more stable as the voltage is increased, and when the voltage is smaller than-7V, the current ratio is more stable as the voltage is reduced, and the detection accuracy of the illumination is smaller. Therefore, when the voltage range to which the first voltage belongs is (-7V, 40v), the first voltage needs to be decreased to improve the detection accuracy, and when the voltage range to which the first voltage belongs is [ -20V, -7V), the voltage needs to be increased to decrease the absolute value of the voltage, and the detection range needs to be decreased to improve the detection accuracy. Similarly, the second voltage is also adjusted.
And S103, respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor.
Specifically, the voltage is increased or decreased according to the adjustment direction, 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 then the current passing through the first thin film transistor is the third current, and 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, so that 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, and the currents passing through the first thin film transistor and the second thin film transistor can be detected with higher detection accuracy, so that the detection result of the currents is more accurate.
The first voltage and the second voltage are respectively adjusted according to the adjustment direction to obtain a third voltage and a fourth voltage, which may specifically be: and respectively determining a first adjustment step length of the first voltage and a second adjustment step length corresponding to the second voltage according to the comparison result of the first current and the second current with the preset current threshold, and respectively adjusting the first voltage and the second voltage into a third voltage and a fourth voltage according to the adjustment direction, the first adjustment step length and the second adjustment step length. Thus, a first adjustment step length and a second adjustment step length are determined according to the difference between the first current and the preset current threshold value and the difference between the second current and the preset current threshold value, so that the first voltage is adjusted to be the third voltage according to the first adjustment step length, and the second voltage is adjusted to be the fourth voltage according to the second adjustment step length.
The difference value of the first voltage and the second voltage can be the same as the difference value of the third voltage and the fourth voltage, so that the first adjustment step length and the second adjustment step length are equal, the first adjustment step length and the second adjustment step length can be obtained only by calculating the voltage difference value once, and the processing process is simplified.
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 through one-time adjustment, and in order to realize measurement with higher precision, the adjustment step value for adjusting the first voltage and the second voltage can be larger. When the first voltage is adjusted to be the third voltage and the second voltage is adjusted to be the fourth voltage, the third voltage and the fourth voltage can be obtained through multiple times of adjustment, and in order to achieve measurement with higher precision, the adjustment step value for adjusting the first voltage and the second voltage can be smaller.
Before 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, the third voltage and the fourth voltage can be adjusted into a fifth voltage and a sixth voltage respectively through once adjustment according to the adjustment direction, the first adjustment step length and the second adjustment step length, the fifth current passing through the first thin film transistor and the sixth current passing through the second thin film transistor are detected, and whether the fifth current and the sixth current exceed a preset current range or not is judged.
If the fifth current and the sixth current do not exceed the preset current range, the detection range can be further reduced, the detection accuracy is improved, and the voltage between the gate and the source of the thin film transistor is further changed until the current flowing through the thin film transistor exceeds the preset current range. Of course, it may also be considered that the fifth voltage and the sixth voltage improve the detection accuracy, the illumination intensity of the first thin film transistor may be calculated according to the fifth voltage, the sixth voltage, the fifth current and the sixth current, and the calculation manner of the illumination intensity may refer to S104.
And if at least one of the fifth current and the sixth current exceeds a preset current range, the fifth voltage and the sixth voltage exceed a reasonable range, and the detection accuracy is maximum under the third voltage and the fourth voltage, performing an operation of determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.
And S104, if the third current and the fourth current belong to a preset current range, determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.
Specifically, if the third current and the fourth current belong to a preset current range, and it is indicated that the third current and the fourth current are within a proper 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, because the third current and the fourth current are respectively obtained under the third voltage and the fourth voltage, and the third voltage and the fourth voltage make the illumination detection precision larger, the illumination intensity of the illuminated thin film transistor can be determined under the larger illumination detection precision. In other words, in the embodiment of the application, the range and the precision of illumination detection can be adjusted according to the detected current, so that illumination is detected by using a proper measurement range and precision, the proper measurement range can be suitable for more detection scenes, and the proper precision can enable the detection result to be more accurate.
In the embodiment of the present application, the same voltage may 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, the third voltage is equal to the fourth voltage, the third current is a current passing through the illuminated thin film transistor at the third voltage, the fourth current is a current passing through the non-illuminated thin film transistor at the third voltage, and the difference between the third current and the fourth current is only whether the thin film transistor is illuminated or not illuminated.
Determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current, which may be specifically, taking a ratio of the third current and the fourth current as an actual current ratio, and determining the illumination intensity corresponding to the actual current ratio as the illumination intensity of the first thin film transistor according to a corresponding relationship between the current ratio and the illumination intensity under the third voltage.
Specifically, the third current and the fourth current measured under the same voltage are compared to obtain an actual current ratio, calculation is simple, the process is simplified, and then the illumination intensity corresponding to the actual current ratio is searched under the third voltage according to the known corresponding relation, so that the illumination intensity of the first thin film transistor is obtained. The corresponding relation may be some discrete points or may be a function analytic equation.
In the embodiment of the present application, different voltages may 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 a difference voltage may be provided therebetween, that is, a difference between the first voltage and the second voltage is used as a difference voltage, a difference between the third voltage and the fourth voltage is a difference voltage, 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 difference voltage may be 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 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, which may be specifically that the fourth current is subjected to numerical correction according to the third voltage and the fourth voltage to obtain a reference current, a ratio of the third current and the reference current is used as an actual current ratio, and the illumination intensity corresponding to the actual current ratio is determined as the illumination intensity of the first thin film transistor according to a corresponding relationship between the current ratio and the illumination intensity under the third voltage.
The third current and the fourth current are different in voltage, so that the actual current ratio cannot be calculated to represent the illumination intensity under different conditions, the fourth current needs to be corrected according to the corresponding relation between the voltage and the current to obtain a reference current corresponding to the third voltage, and thus the reference current and the third current are at the same voltage to calculate the actual current ratio so as to represent the illumination 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 without interfering with each other, and the flexibility of voltage adjustment can be increased.
The embodiment of the application provides a light intensity detection method, a first voltage is provided between a grid electrode and a source electrode of a first thin film transistor which is illuminated, a second voltage is provided between a grid electrode and a source electrode of a second thin film transistor which is not illuminated, a first current passing through the first thin film transistor and a second current passing through the second thin film transistor are detected, then the first current and the second current are determined to belong to a preset current range, the first current and the second current are ensured to be in a proper range, the measuring equipment can be prevented from being burnt out by too much current, the current can also be prevented from being too small to be measured, then the adjustment directions of the first voltage and the second voltage are determined according to the voltage range to which the first voltage and the second voltage belong, voltage adjustment operation based on the adjustment directions is used for improving illumination detection accuracy, the adjustment directions comprise increasing or decreasing, the first voltage and the second voltage are respectively adjusted according to the adjustment directions, a third voltage and a fourth voltage are obtained, the illumination of the first thin film transistor can be firstly detected with smaller accuracy under smaller accuracy, the smaller range, the illumination detection accuracy can be improved by the larger range, and the illumination detection accuracy can be improved by the larger range.
The method comprises the steps of detecting to obtain a third current passing through a first thin film transistor and a fourth current passing through a second thin film transistor, if the third current and the fourth current belong to a preset current range, and the third current and the fourth current are in a proper range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current, wherein the third current and the fourth current are respectively obtained under the third voltage and the fourth voltage, and the third voltage and the fourth voltage enable the illumination detection precision to be larger, so that the illumination intensity of the illuminated thin film transistor can be determined under the larger illumination detection precision.
Based on the above light intensity detection method, an embodiment of the present application further provides a light intensity detection circuit, as shown in fig. 6, for a structural block diagram of the light intensity detection circuit provided in the 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, where the first thin film transistor 100 is an illuminated thin film transistor, and the second thin film transistor 200 is an un-illuminated thin film transistor, when light irradiates the first thin film transistor 100, compared to the second thin film transistor 200, a current passing through the first thin film transistor 100 may change, and the detection module may be an IC circuit.
The detection module 300 is configured 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 through the first thin film transistor 100 and a second current through the second thin film transistor 200; after the first current and the second current are determined to belong to a preset current range, determining the adjustment directions of the first voltage and the second voltage according to the voltage ranges to which the first voltage and the second voltage belong, and performing voltage adjustment operation based on the adjustment directions to improve the illumination detection precision, wherein the adjustment directions comprise increasing or decreasing; respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to 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, the illumination intensity of the first thin film transistor 100 is determined according to the third voltage, the fourth voltage, the third current and the fourth current.
In this 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 referring to fig. 7, for a structural block diagram of another light intensity detecting circuit provided in this embodiment of the present application, a first thin film transistor 100 and a second thin film transistor 200 are connected in parallel and connected to a detecting module 300, a first end of the detecting module 300 is connected to a gate of the first thin film transistor 100 and a gate of the second thin film transistor 200 at the same time, so that the first voltage may be equal to the second voltage, the third voltage is equal to the fourth voltage, a second end of the detecting module 300 is connected to a source of the first thin film transistor 100 and a source of the second thin film transistor 200, a third end of the detecting module 300 is connected to a drain of the first thin film transistor 100 for detecting a current passing through the first thin film transistor 100, a fourth end of the detecting module 300 is connected to a drain of the second thin film transistor 200 for detecting a current passing through the second thin film transistor 200, and a magnitude of a current passing through the thin film transistor may be controlled by controlling a voltage between the gate and the source of the thin film transistor.
Determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current, which may specifically be:
taking the ratio of the third current and the fourth current as an actual current ratio;
and determining the illumination intensity corresponding to the actual current ratio as the illumination intensity of the first thin film transistor according to the corresponding relation between the current ratio and the illumination intensity under the third voltage.
In the embodiment of the present application, the light intensity detecting circuit further includes a first voltage compensating module 400, configured to compensate the voltage output by the detecting module to obtain a first voltage and a third voltage, or to obtain a second voltage and a fourth voltage. Referring to fig. 8, a block diagram of another light intensity detecting circuit provided in this embodiment of the present application includes a first thin film transistor 100, a second thin film transistor 200, a detecting module 300, and a first voltage compensating module 400, where the detecting module 300 provides a voltage to the gates of the first thin film transistor 100 and the second thin film transistor 200 through the first voltage compensating module 400, and the first voltage compensating module 400 may adjust the voltage transmitted to the gates of the first thin film transistor 100 and the second thin film transistor 200 according to the voltage provided by the detecting module 300 to control the voltage applied to the first thin film transistor 100 and the second thin film transistor 200.
In the embodiment of the present application, the light intensity detecting circuit further includes a second voltage compensating module 500 and a third voltage compensating module 600;
the second voltage compensation module 500 is configured to compensate the voltage output by the detection module to obtain a first voltage or a third voltage; the second voltage compensation module generates a first compensation voltage;
the third voltage compensation module 600 is configured 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;
a difference value between the first compensation voltage and the second compensation voltage is used as a difference voltage, a difference value between the first voltage and the second voltage is used as a difference voltage, a difference value between the third voltage and the fourth voltage is used as a 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. Referring to fig. 9, a block diagram of a further light intensity detecting circuit according to an embodiment of the present disclosure includes a first thin film transistor 100, a second thin film transistor 200, a detecting module 300, a second voltage compensating module 500, and a third voltage compensating module 600, where the detecting module provides a voltage to a gate of the first thin film transistor through the second voltage compensating module, and provides a voltage to a gate of the second thin film transistor through the third voltage compensating module, and the second voltage compensating module and the third voltage compensating module can adjust voltages transmitted to the gates of the first thin film transistor and the second thin film transistor respectively according to the voltage provided by the detecting module.
In this embodiment of the application, the second voltage compensation module and the third voltage compensation module may be passive circuits or active circuits, and when the second voltage compensation module and the third voltage compensation module are passive circuits, the detection module may supply power to the second voltage compensation module and the third voltage compensation module. Referring to fig. 10, in a block diagram of a structure of another light intensity detecting circuit provided in the embodiment of the present application, a second voltage compensating module and a third voltage compensating module are respectively connected to a fifth terminal and a sixth terminal of a detecting module, so that the detecting module can supply power to the second voltage compensating module and the third voltage compensating module.
The embodiment of the application provides a light intensity detection circuit, which comprises a first thin film transistor, a second thin film transistor and a detection module, wherein the detection module is used for providing a first voltage between a grid electrode and a source electrode of the illuminated first thin film transistor, providing a second voltage between the grid electrode and the source electrode of the second thin film transistor which is not illuminated, detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor, and then determining that the first current and the second current belong to a preset current range.
The method comprises the steps of detecting to obtain a third current passing through a first thin film transistor and a fourth current passing through a second thin film transistor, if the third current and the fourth current belong to a preset current range, and the third current and the fourth current are in a proper range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current, wherein the third current and the fourth current are respectively obtained under the third voltage and the fourth voltage, and the third voltage and the fourth voltage enable the illumination detection precision to be larger, so that the illumination intensity of the illuminated thin film transistor can be determined under the larger illumination detection precision.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the embodiment of the detection circuit, since it is basically similar to the embodiment of the detection method, the description is simple, and the relevant points can be referred to the partial description of the embodiment of the method.
The foregoing is merely a preferred embodiment of the present application and, although the present application discloses the foregoing preferred embodiments, the present application is not limited thereto. Those skilled in the art can make numerous possible variations and modifications to the disclosed solution, or modify it to equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the claimed solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still fall within the protection scope of the technical solution of the present application without departing from the content of the technical solution of the present application.

Claims (13)

1. A method of detecting light intensity, the method comprising:
providing a first voltage between a gate and a source of a first thin film transistor that is illuminated, providing a second voltage between a gate and a source of a second thin film transistor that is not illuminated, and detecting a first current through the first thin film transistor and a second current through the second thin film transistor;
after the first current and the second current are determined to belong to a preset current range, according to voltage ranges to which the first voltage and the second voltage belong, determining adjustment directions of the first voltage and the second voltage, wherein voltage adjustment operation based on the adjustment directions is used for improving illumination detection precision, and the adjustment directions comprise increasing or decreasing;
respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor;
and if the third current and the fourth current belong to the preset current range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current.
2. The method of claim 1, wherein the first voltage is equal to the second voltage, wherein the third voltage is equal to the fourth voltage, and wherein determining the illumination intensity of the first thin film transistor based on the third voltage, the fourth voltage, the third current, and the fourth current comprises:
taking the ratio of the third current and the fourth current as an actual current ratio;
and determining the illumination intensity corresponding to the actual current ratio as the illumination intensity of the first thin film transistor according to the corresponding relation between the current ratio and the illumination intensity under the third voltage.
3. The method according to claim 1, wherein a difference between the first voltage and the second voltage is a difference voltage, a 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;
the determining the illumination 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, carrying out numerical correction on the fourth current to obtain a reference current;
taking the ratio of the third current and the reference current as an actual current ratio;
and determining the illumination intensity corresponding to the actual current ratio as the illumination intensity of the first thin film transistor according to the corresponding relation between the current ratio and the illumination intensity under the third voltage.
4. The method according to any one of claims 1-3, wherein said adjusting said first voltage and said second voltage according to said adjustment direction, respectively, to obtain a third voltage and a fourth voltage, comprises:
respectively determining a first adjustment step length of the first voltage and a second adjustment step length corresponding to the second voltage according to the comparison result of the first current and the second current with a preset current threshold;
and adjusting the first voltage and the second voltage into the third voltage and the fourth voltage respectively according to the adjustment direction, the first adjustment step length and the second adjustment step length.
5. The method of claim 4, wherein 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 wherein the first adjustment step size and the second adjustment step size are equal.
6. The method of claim 4, wherein before determining the illumination intensity of the first thin film transistor from the third voltage, the fourth voltage, the third current, and the fourth current, the method further comprises:
adjusting the third voltage and the fourth voltage into a fifth voltage and a sixth voltage respectively through one-time adjustment according to the adjustment direction, the first adjustment step length and the second adjustment step length, and detecting to obtain a fifth current passing through the first thin film transistor and a sixth current passing through the second thin film transistor;
and if at least one of the fifth current and the sixth current exceeds the preset current range, executing the operation of determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current.
7. The method according to any one of claims 1-3, wherein 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 comprises:
determining that the adjustment directions of the first voltage and the second voltage are decreasing if the voltage ranges from (-7,40);
if the voltage ranges of the first voltage and the second voltage are [ -20, -7), the adjustment direction of the first voltage and the second voltage is determined to be increasing.
8. The method of any of claims 1-3, wherein prior to determining that the first current and the second current fall within a preset current range, the method further comprises:
if the first current is determined to be larger than the maximum value of the preset current range, reducing the first voltage and the second voltage so as to enable the first current and the second current to belong to the preset current range;
and if the second current is determined to be smaller than the minimum value of the preset current range, increasing the first voltage and the second voltage so as to enable the first current and the second current to belong to the preset current range.
9. The method of claim 8, wherein the first voltage and the second voltage belong to a preset voltage range, and wherein 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 detecting circuit, comprising: the device comprises a first thin film transistor, a second thin film transistor and a detection module;
the detection module is used for providing a first voltage between a grid electrode and a source electrode of a first thin film transistor which is illuminated, providing a second voltage between a grid electrode and a source electrode of a second thin film transistor which is not illuminated, and detecting a first current passing through the first thin film transistor and a second current passing through the second thin film transistor; after the first current and the second current are determined to belong to a preset current range, according to voltage ranges to which the first voltage and the second voltage belong, determining adjustment directions of the first voltage and the second voltage, wherein voltage adjustment operation based on the adjustment directions is used for improving illumination detection precision, and the adjustment directions comprise increasing or decreasing; respectively adjusting the first voltage and the second voltage according to the adjustment direction to obtain a third voltage and a fourth voltage, and detecting to obtain a third current passing through the first thin film transistor and a fourth current passing through the second thin film transistor; and if the third current and the fourth current belong to the preset current range, determining the illumination intensity of the first thin film transistor according to a third voltage, a fourth voltage, the third current and the fourth current.
11. The circuit of claim 10, wherein the first voltage is equal to the second voltage, the third voltage is equal to the fourth voltage, and the determining the illumination intensity of the first thin film transistor according to the third voltage, the fourth voltage, the third current and the fourth current comprises:
taking the ratio of the third current and the fourth current as an actual current ratio;
and determining the illumination intensity corresponding to the actual current ratio as the illumination intensity of the first thin film transistor according to the corresponding relation between the current ratio and the illumination intensity under the third voltage.
12. The light intensity detecting circuit of claim 11, further comprising a first voltage compensating module for compensating the voltage outputted from the detecting module to obtain the first voltage and the third voltage, or to obtain the second voltage and the fourth voltage.
13. The light intensity detecting circuit according to claim 10, further comprising a second voltage compensating module and a third voltage compensating module;
the second voltage compensation module is used for compensating 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 for compensating 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;
a difference between the first compensation voltage and the second compensation voltage is used as a difference voltage, a difference between the first voltage and the second voltage is used as the difference voltage, a difference between the third voltage and the fourth voltage is used as 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.
CN202210907217.5A 2022-07-29 2022-07-29 Light intensity detection method and light intensity detection circuit Pending CN115265774A (en)

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Application Number Priority Date Filing Date Title
CN202210907217.5A CN115265774A (en) 2022-07-29 2022-07-29 Light intensity detection method and light intensity detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210907217.5A CN115265774A (en) 2022-07-29 2022-07-29 Light intensity detection method and light intensity detection circuit

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CN115265774A true CN115265774A (en) 2022-11-01

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