Light detection element

Abstract

The present invention provides a light detection element, including a first light detection unit, a second light detection unit and a driving transistor. The first light detection unit includes a first transistor and a first light sensing unit. The first transistor and the first light sensing unit are electrically connected. The second light detection unit is electrically connected to the first light detection unit. The second light detection unit includes a second light sensing unit and a second transistor. The second light sensing unit and the second transistor are electrically connected. The driving transistor has a gate terminal. The gate terminal is electrically connected to the first light sensing unit and the second light sensing unit. In a time interval, the first transistor is not turned on, and the second transistor is turned on.

Description

Technical Field

[0001] The present invention relates to a detection element, and more particularly to a light detection element. Background Art

[0002] When the light detection element is used in a display, a pixel light source can generally be used as a detection light source. The light detection element detects the reflected light of the object to determine whether the object touches the display at this time, and can further determine the touch position of the object. However, if the display content of the display happens to be dark, there is no reflected light for the light detection element to detect. In other words, the light detection element will be affected by the display content of the display, resulting in incorrect detection results. For example, in addition to the display content of the display being dark and no reflected light detection, changes in the color and brightness of the display content will also interfere with the detection results of the light detection element. In addition, the light detection element is also easily affected by ambient light during detection. Summary of the invention

[0003] The present invention provides a light detection element, which can effectively reduce the influence of noise on the detection result to avoid misjudgment.

[0004] According to an embodiment of the present invention, the light detection element includes a first light detection unit, a second light detection unit and a driving transistor. The first light detection unit includes a first transistor and a first light sensing unit. The first transistor and the first light sensing unit are electrically connected. The second light detection unit is electrically connected to the first light detection unit. The second light detection unit includes a second light sensing unit and a second transistor. The second light sensing unit and the second transistor are electrically connected. The driving transistor has a gate terminal. The gate terminal is electrically connected to the first light sensing unit and the second light sensing unit. In a time interval, the first transistor is not turned on, and the second transistor is turned on.

[0005] In an embodiment of the present invention, the light detection element further comprises a light source, and the light source operates synchronously with the first transistor.

[0006] In an embodiment of the present invention, one terminal of the first transistor is coupled to a first voltage, and one terminal of the second transistor is coupled to a second voltage, and the potential of the first voltage is different from that of the second voltage.

[0007] In an embodiment of the present invention, the first transistor is controlled by a first signal, and the second transistor is controlled by a second signal.

[0008] In an embodiment of the present invention, the light detection element further includes a control circuit, which is used to determine whether to allow the second signal to control the second transistor.

[0009] In an embodiment of the present invention, the control circuit includes a readout circuit.

[0010] In an embodiment of the present invention, the readout circuit does not include an analog-to-digital converter.

[0011] In an embodiment of the present invention, the light detection element further includes a feedback circuit. When the voltage at the gate terminal is the third voltage, the feedback circuit is used to determine whether the light detection element detects reflected light. When the voltage at the gate terminal is the fourth voltage, the feedback circuit is used to determine whether the light detection element detects direct light.

[0012] In an embodiment of the present invention, when the feedback circuit determines that the light detection element detects reflected light, the control circuit enables the second signal to allow the second signal to control the second transistor to turn on.

[0013] In an embodiment of the present invention, when the feedback circuit determines that the light detection element detects direct light, the control circuit disables the second signal so that the second signal controls the second transistor to be non-conductive. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram showing a light detection element for detecting reflected light according to an embodiment of the present invention;

[0015] Figure 2 Show Figure 1 A schematic structural diagram of a light detection element of an embodiment;

[0016] Figure 3 Show Figure 2 A signal timing diagram of a control signal used to control each transistor in an embodiment;

[0017] Figure 4 Show Figure 2 Operation flow chart of the light detection element of the embodiment;

[0018] Figure 5 A schematic diagram showing the structure of a light detection element according to an embodiment of the present invention;

[0019] Figure 6 Show Figure 5 A signal timing diagram of a control signal used to control each transistor in an embodiment;

[0020] Figure 7 A schematic diagram showing a light detection element according to an embodiment of the present invention for detecting reflected light and direct light;

[0021] Figure 8 Show Figure 7 A schematic structural diagram of a light detection element of an embodiment;

[0022] Fig. 9 Show Figure 8 A signal timing diagram of a control signal used to control each transistor in an embodiment;

[0023] Fig.10 Show Figure 8 Operation flow chart of the light detection element of the embodiment;

[0024] Fig.11 A schematic diagram showing the structure of a light detection element according to an embodiment of the present invention;

[0025] Fig.12 Show Fig.11 A signal timing diagram of a control signal used to control each transistor in an embodiment. DETAILED DESCRIPTION

[0026] The present disclosure may be understood by referring to the following detailed description in conjunction with the accompanying drawings. It should be noted that, in order to facilitate the understanding of the readers and for the simplicity of the drawings, the multiple drawings in the present disclosure only show a part of the electronic device, and certain elements in the drawings are not shown according to the actual scale. In addition, the number and size of each element in the drawings are only for illustration and are not intended to limit the scope of the present disclosure.

[0027] In the following description and claims, the words “including” and “comprising” are open-ended words and thus should be interpreted as meaning “including but not limited to…”.

[0028] It should be understood that when an element or film layer is referred to as being "on" or "connected to" another element or film layer, it may be directly on or directly connected to the other element or layer, or there may be an intervening element or film layer between the two (indirect case). Conversely, when an element is referred to as being "directly" "on" or "directly connected to" another element or film layer, there may be no intervening element or film layer between the two.

[0029] Although the terms first, second, third, etc. can be used to describe a variety of components, the components are not limited to these terms. These terms are only used to distinguish a single component from other components in the specification. The same terms may not be used in the claims, but may be replaced by first, second, third, etc. according to the order in which the components are declared in the claims. Therefore, in the following description, the first component may be the second component in the claims.

[0030] In the text, the terms "about", "approximately", "substantially", and "roughly" generally mean within 10%, or within 5%, or within 3%, or within 2%, or within 1%, or within 0.5% of a given value or range. The number given here is an approximate number, that is, in the absence of a specific description of "about", "approximately", "substantially", and "roughly", the meanings of "about", "approximately", "substantially", and "roughly" can still be implied. In addition, the terms "range is from a first value to a second value", "range is between a first value and a second value" mean that the range includes the first value, the second value, and other values ​​between them.

[0031] In some embodiments of the present disclosure, terms such as "connection" and "interconnection" may refer to two structures being in direct contact, or two structures not being in direct contact, with another structure disposed between the two structures, unless otherwise specified. Such terms may also include situations where both structures are movable or both structures are fixed. In addition, the term "coupling" includes any direct and indirect electrical connection means.

[0032] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0033] Figure 1 A schematic diagram showing a light detection element for detecting reflected light according to an embodiment of the present invention is shown. Figure 1 , the light detection element 100 of this embodiment is used to detect the reflected light L2 from the object 200. The light source 300 is used to output the light L1. The light L1 is visible light or invisible light. The light source 300 that outputs visible light is, for example, a laser light source. The light source 300 that outputs invisible light is, for example, an infrared light source. The light source 300 can be a display light or a non-display light source according to the product design. In this embodiment, the light source 300 will be described as a non-display light source, but it is not limited to this. In other words, when the light L1 output by the light source 300 is a non-display light source, it will not contain information about the display content. The object 200 can be a pen or a user's finger. The object 200 is used to reflect the light L1, and reflects the reflected light L2 to the light detection element 100. In this embodiment, the light sensing unit D1 / D2 includes, for example, a phototransistor or a PIN junction photodiode (PIN photo diode).

[0034] The light detection element 100 of the present embodiment is applied in an electronic device. The electronic device disclosed in the present invention may include a display device, an antenna device, a sensing device, a touch display, a curved display or a free shape display, but is not limited thereto. The electronic device may be a bendable or flexible electronic device. The electronic device may, for example, include a light emitting diode (LED), a liquid crystal, fluorescence, phosphor, a quantum dot (QD), other suitable display media, or a combination thereof, but is not limited thereto. The display may be a self-luminous display, such as an organic light emitting diode display, a sub-millimeter light emitting diode (mini LED) display, a micro LED display, or a quantum dot light emitting diode (quantum dot, QD, which may be, for example, QLED, QDLED) display. The present invention does not limit the type of display.

[0035] Figure 2 Show Figure 1 Schematic diagram of the structure of the light detection element of the embodiment. Please refer to Figure 2 , the light detection element 100 of the present embodiment includes a sensing pixel 110 and a control circuit 120. The sensing pixel 110 is connected to the control circuit 120 through a sensing line SL to transmit the sensed signal to the control circuit 120. The sensing pixel 110 includes a first light detection unit 112 and a second light detection unit 114, and the first light detection unit 112 is electrically connected to the second light detection unit 114. More specifically, the sensing pixel 110 includes a first transistor T1, a first light sensing unit D1, a second light sensing unit D2, a second transistor T2 and a driving transistor T_dri. The first transistor T1, the first light sensing unit D1, the second light sensing unit D2 and the second transistor T2 are electrically connected. Please refer to Figure 2In this embodiment, the first transistor T1, the first light sensing unit D1, the second light sensing unit D2 and the second transistor T2 are connected in series. The product circuit can be set in parallel according to the requirements or the product circuit can include both series and parallel connections, but it is not limited to this. The driving transistor T_dri has a gate terminal G. The gate terminal G is electrically connected to the anode terminal of the first light sensing unit D1 and the cathode terminal of the second light sensing unit D2. One end of the first transistor T1 is coupled to a first voltage, such as a high level voltage V1, and the other end is coupled to the cathode terminal of the first light sensing unit D1. One end of the second transistor T2 is coupled to a first voltage, such as a low level voltage V2, and the other end is coupled to the anode terminal of the second light sensing unit D2, but it is not limited to this. The first transistor T1 is controlled by the first signal S1, and the second transistor T2 is controlled by the second signal S2. One end of the driving transistor T_dri is coupled to the first system voltage VDD, and the other end is coupled to the first output terminal OUT. The driving transistor T_dri is controlled by the voltage of the gate terminal G.

[0036] In this embodiment, the light detection element 100 further includes a light source 300 that operates synchronously with the first transistor T1. That is, when the first transistor T1 is turned on, the light source 300 will be illuminated. In this embodiment, the sensing pixel 110 further includes a reset transistor T_rst, a sampling transistor Ts and a storage capacitor C1.

[0037] Figure 3 Show Figure 2 A signal timing diagram of a control signal used to control each transistor in an embodiment. Figure 4 Show Figure 2 Please refer to the operation flow chart of the light detection element of the embodiment. Figures 2 to 4 In step S100, the reset signal S3 turns on the reset transistor T_rst in the time interval t1 to reset one end of the storage capacitor C1 to the reference voltage Vref. That is, the voltage of the gate terminal G of the driving transistor T_dri is reset to the reference voltage Vref. Therefore, the voltage of the first output terminal OUT is the reference voltage Vref minus the threshold voltage Vth of the driving transistor T_dri, that is, Vref-Vth, and the voltage of the second output terminal OUTb is a third voltage, such as a low-level voltage L. In the time interval t1, the first transistor T1 and the second transistor T2 are not turned on.

[0038] In step S110, the light detection element 100 is used to detect ambient light. In step S110, the second signal S2 turns on the second transistor T2 in the time interval t2, and the second light sensing unit D2 detects ambient light. In the time interval t2, the first transistor T1, the reset transistor T_rst and the driving transistor T_dri are not turned on. Therefore, the storage capacitor C1 discharges the second transistor T2, so that the voltage of the gate terminal G is pulled down from the reference voltage Vref to the low level voltage L. At this time, since the driving transistor T_dri is not turned on, the voltage of the first output terminal OUT is maintained at the reference voltage Vref minus the threshold voltage Vth of the driving transistor T_dri, that is, Vref-Vth, and the voltage of the second output terminal OUTb is still the low level voltage L.

[0039] In step S120, the light detection element 100 is used to detect ambient light or sensing light. For example, when the finger 200 is not present, the light detection element 100 detects ambient light in step S120. On the contrary, when the finger 200 is close to the light source 300, the light L1 is reflected to form reflected light L2, and the reflected light L2 is reflected to the light detection element 100. Therefore, at this time, the light detection element 100 detects sensing light (i.e., reflected light L2) in step S120.

[0040] In step S120, the first signal S1 turns on the first transistor T1 in the time interval t3, and the light source 300 is also lit to output the light L1, indicating that the light source 300 operates synchronously with the first transistor T1. In detail, the light source 300 referred to in this embodiment can be, for example, controlled to turn on or off by another set of control circuits (not shown). When the first signal S1 turns on the first transistor T1 in the time interval t3, the other set of control circuits (not shown) will turn on the light source 300 at the same time, but it is not limited to this. In the time interval t3, the second transistor T2 and the reset transistor T_rst are not turned on. When the finger 200 approaches the light source 300, the first light sensing unit D1 detects the reflected light L2, and the high-level voltage V1 charges the storage capacitor C1, so that the voltage of the gate terminal G is pulled up to the high-level voltage H, so that the driving transistor T_dri is turned on. Therefore, the voltage of the first output terminal OUT is a fourth voltage, for example, the high-level voltage H minus the threshold voltage Vth of the driving transistor T_dri, that is, H-Vth.

[0041] Next, in step S130, the light detection element 100 samples the sensing signal. In the time interval t4, the sampling signal S4 turns on the sampling transistor Ts. In the time interval t4, the first transistor T1, the second transistor T2 and the reset transistor T_rst are not turned on. The voltage of the second output terminal OUTb is the high level voltage H minus the threshold voltage Vth of the driving transistor T_dri, that is, H-Vth. Therefore, in the time interval t4, the sensing pixel 110 can output the sensing signal to the control circuit 120 through the sensing line SL, and the sensing signal is the signal obtained by the sensing pixel 110 sensing the reflected light L2.

[0042] Therefore, in step S120, when the finger 200 is close to the light source 300, the sampling result of the second output terminal OUTb in step S130 will be a high-level voltage H minus the threshold voltage Vth of the driving transistor T_dri, that is, H-Vth, indicating that the light detection element 100 detects that the finger 200 is close to the light source 300. Conversely, in step S120, when the finger 200 does not exist, the sampling result of the second output terminal OUTb in step S130 will be a low-level voltage L, indicating that the finger 200 does not exist and the light detection element 100 does not detect that the finger 200 is close to the light source 300.

[0043] Please refer to Figure 2 In this embodiment, the control circuit 120 includes a readout circuit 410, an operation circuit 420 and a system circuit 430. The readout circuit 410 includes a signal receiving circuit 412. The readout circuit 410 reads out the sensing signal output by the sensing pixel 110 through the sensing line SL. As described above, if the sensing signal read out is a low-level voltage L, it indicates that the finger 200 does not exist; if the sensing signal read out is a high-level voltage H-Vth, it indicates that the light detection element 100 detects that the finger 200 is close to the light source 300. Therefore, the sensing signal received by the signal receiving circuit 412 in the readout circuit 410 is in the form of a digital signal, and the detection result can be represented by two different levels of high and low. Therefore, there is no need to set up an analog-to-digital converter in the readout circuit 410 to convert the sensing signal into a digital signal. Next, the operation circuit 420 receives the sensing signal output by the signal receiving circuit 412 to calculate the position touched by the finger 200, and then transmits the touch position to the system circuit 430 for subsequent processing.

[0044] exist Figure 2 In the embodiment of the present invention, each transistor in the sensing pixel 110 is implemented by an N-type transistor, but the present invention is not limited thereto. In another embodiment, each transistor in the sensing pixel 110 may also be implemented by a P-type transistor.

[0045] Figure 5 A schematic structural diagram of a light detection element according to an embodiment of the present invention is shown. Figure 6 Show Figure 5 The signal timing diagram of the control signal used to control each transistor in the embodiment. Please refer to Figure 2 , Figure 5 , Figure 6 The light detection element 100 of this embodiment is similar to Figure 2 The light detection element of the embodiment, but the main difference between the two is that Figure 5 Each transistor in the sensing pixel 110 is implemented as a P-type transistor. Figure 6 The control signal used to control the conduction state of each transistor has its level adjusted from a high level to a low level.

[0046] exist Figures 1 to 6 In the embodiment, when the light source path detected by the light detection element 100 is reflective, the non-display light source 300 is used as the detection light source, and the timing of the light source 300 being lit is synchronized with the timing of the first transistor T1 being turned on, so that the first light sensing unit D1 detects the reflected light, which can avoid the detection result being affected by the display light source, and improve the accuracy of the detection of the light detection element 100. In addition, the light detection element 100 controls the first transistor T1 and the second transistor T2 to be turned on in a time-sharing manner to charge and discharge the storage capacitor C1, which can effectively reduce the detection result being affected by noise, thereby avoiding misjudgment of the light detection element 100.

[0047] exist Figures 1 to 6 In the embodiment of the present invention, the light detection element 100 detects the reflected light L2 from the object 200, but the present invention is not limited thereto. In other embodiments, the light detection element 100 can also be used to detect the light source directly output by another object.

[0048] Figure 7 A schematic diagram showing a light detection element according to an embodiment of the present invention for detecting reflected light and direct light. Figure 7 In addition to detecting the reflected light L2, the light detection element 700 of this embodiment can also be used to detect the light L3 actively emitted by another object 500. For example, the object 500 is a laser pen or other similar device that actively emits the light L3. Therefore, in this embodiment, the light detection element 700 can also detect the light source output by the laser pen 500.

[0049] Figure 8 Show Figure 7 Schematic diagram of the structure of the light detection element of the embodiment. Please refer to Figure 8, the light detection element 700 of this embodiment includes a sensing pixel 710 and a control circuit 120. The sensing pixel 710 is connected to the control circuit 120 through a sensing line SL to transmit a sensing signal to the control circuit 120. The sensing pixel 710 also includes a feedback circuit 712 for determining whether the light detection element 700 detects the reflected light L2 or the direct light L3.

[0050] Specifically, Fig. 9 Show Figure 8 A signal timing diagram of a control signal used to control each transistor in an embodiment. Fig.10 Show Figure 8 Please refer to the operation flow chart of the light detection element of the embodiment. Figures 8 to 10 In step S200, the reset signal S30 turns on the transistors T0_b and T0_c in the time interval t01 to reset the gate terminal G and the node B to the high level voltage H and the low level voltage L, respectively. At the same time, the reset signal S5 turns on the transistor T0_a in the time interval t01 to reset the node A to the high level voltage H. In the time interval t01, since the gate terminal G is the high level voltage H, the driving transistor T_dri is turned on.

[0051] In step S210, the reset signal S5 continuously turns on the transistor T0 during the time interval t02 to detect whether the direct light L3 is irradiated on the second light sensing unit D2. If the direct light L3 is irradiated on the second light sensing unit D2, the voltage of the gate terminal G will be pulled down to a low level voltage L. On the contrary, if the direct light L3 is not irradiated on the second light sensing unit D2, the voltage of the gate terminal G is maintained at a high level voltage H.

[0052] When there is no direct light L3 irradiating the second light sensing unit D2, the operation process of the light detection element 700 will execute steps S100, S110, S120, and S130 to detect the reflected light L2. In step S110, the control circuit 120 will enable the second signal S2 during the time interval t2 to turn on the second transistor T2, so that the second light sensing unit D2 can detect the ambient light. Fig.10 In the embodiment of the present invention, the operation method of detecting the reflected light L2 can be performed by Figure 4 Sufficient teachings, suggestions and implementation instructions are obtained in the embodiments and will not be repeated here.

[0053] When direct light L3 is irradiated on the second light sensing unit D2, the operation flow of the light detection element 700 will execute step S220. In step S220, the reset signal S3 turns on the reset transistor T_rst in the time interval t1 to reset one end of the storage capacitor C1 to the reference voltage Vref. In other words, the voltage of the gate terminal G of the driving transistor T_dri is reset to the reference voltage Vref. Therefore, the voltage of the first output terminal OUT is the reference voltage Vref minus the threshold voltage Vth of the driving transistor T_dri, that is, Vref-Vth, and the voltage of the second output terminal OUTb is a low level voltage L. In the time interval t1, the first transistor T1 and the second transistor T2 are not turned on.

[0054] In step S230, the control circuit 120 disables the second signal S2 during the time interval t2, so that the second transistor T2 is not turned on, and the second light sensing unit D2 does not detect the ambient light. In other words, the control circuit 120 can be used to determine whether to allow the second signal S2 to control the second transistor T2. Specifically, the control circuit 120 can include, for example, a circuit (not shown) electrically connected to the second transistor T2.

[0055] In step S240, the light detection element 700 is used to detect direct light L3, which may be output by the laser pen 500, for example. The first signal S1 turns on the first transistor T1 in the time interval t3, so that the first light sensing unit D1 detects the ambient light. In the time interval t3, the second transistor T2 and the reset transistor T_rst are not turned on. When the direct light L3 irradiates the first light sensing unit D1, the first light sensing unit D1 detects the direct light L3, and the high-level voltage V1 charges the storage capacitor C1, so that the voltage of the gate terminal G is pulled up to the high-level voltage H, so that the driving transistor T_dri is turned on. Therefore, the voltage of the first output terminal OUT is the high-level voltage H minus the threshold voltage Vth of the driving transistor T_dri, that is, H-Vth.

[0056] Next, in step S250, the light detection element 700 samples the sensing signal. In the time interval t4, the sampling signal S4 turns on the sampling transistor Ts. In the time interval t4, the first transistor T1, the second transistor T2 and the reset transistor T_rst are not turned on. The voltage of the second output terminal OUTb is the high level voltage H minus the threshold voltage Vth of the driving transistor T_dri, that is, H-Vth. Therefore, in the time interval t4, the sensing pixel 110 can output the sensing signal to the control circuit 120 through the sensing line SL, and the sensing signal is the signal obtained by the sensing pixel 110 sensing the direct light L3.

[0057] Therefore, in step S240, when the direct light L3 irradiates the first light sensing unit D1, the sampling result of the second output terminal OUTb in step S250 will be a high level voltage H minus the threshold voltage Vth of the driving transistor T_dri, ie, H-Vth, indicating that the direct light L3 irradiates the first light sensing unit D1.

[0058] Please refer to Figure 8 In the present embodiment, the control circuit 120 includes a readout circuit 410, an operation circuit 420 and a system circuit 430. The readout circuit 410 includes a signal receiving circuit 412. The readout circuit 410 reads out the sensing signal output by the sensing pixel 110 through the sensing line SL. As described above, in step S210, if the voltage of the gate terminal G is a low-level voltage L, it indicates that direct light L3 is irradiated on the second light sensing unit D2; if the voltage of the gate terminal G is a high-level voltage H, it indicates that no direct light L3 is irradiated on the second light sensing unit D2. Therefore, the control circuit 120 can determine whether direct light L3 is irradiated on the second light sensing unit D2. If direct light L3 is irradiated on the second light sensing unit D2, the control circuit 120 will enable the second signal S2 in step S110 to turn on the second transistor T2, so that the second light sensing unit D2 detects ambient light. If there is no direct light L3 irradiating the second light sensing unit D2, the control circuit 120 will disable the second signal S2 in step S230, so the second transistor T2 is not turned on, and the second light sensing unit D2 does not detect the ambient light. Then, the operation circuit 420 receives the sensing signal output by the signal receiving circuit 412 to calculate the position touched by the finger 200, and then transmits the touch position to the system circuit 430, which outputs the disabled / enabled second signal S2 to the sensing pixel 710.

[0059] exist Figure 8 In the embodiment of the present invention, each transistor in the sensing pixel 710 is implemented by an N-type transistor, but the present invention is not limited thereto. In another embodiment, each transistor in the sensing pixel 710 may also be implemented by a P-type transistor.

[0060] Fig.11 A schematic structural diagram of a light detection element according to an embodiment of the present invention is shown. Fig.12 Show Fig.11 The signal timing diagram of the control signal used to control each transistor in the embodiment. Please refer to Figure 8 , Fig.11 , Fig.12 The light detection element 700 of this embodiment is similar to Figure 8 The light detection element of the embodiment, but the main difference between the two is that Fig.11 Each transistor in the sensing pixel 710 is implemented as a P-type transistor. Fig.12The control signal used to control the conduction state of each transistor has its level adjusted from a high level to a low level.

[0061] exist Figures 7 to 12 In the embodiment, the light detection element 700 can be used to detect the direct light L3 in addition to the reflected light L2. The light detection element 700 includes a feedback circuit 712 to determine whether the light detection element 700 detects the reflected light L2 or the direct light L3.

[0062] In summary, when the light source path detected by the light detection element is reflective, a non-display light source is used as the detection light source, and the timing of the light source being lit is synchronized with the timing of the first transistor being turned on, so that the first light sensing unit detects the reflected light. This can avoid the detection result being affected by the display light source, thereby improving the accuracy of the light detection element detection. In addition, the light detection element controls the conduction of the first transistor and the second transistor in a time-sharing manner to charge and discharge the storage capacitor, which can effectively reduce the impact of noise on the detection result, thereby avoiding misjudgment of the light detection element. In addition to detecting reflected light, the light detection element can also be used to detect direct light. The light detection element includes a feedback circuit to determine whether the light detection element detects reflected light or direct light.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light detection element, comprising: A first light detection unit, the first light detection unit comprising a first transistor and a first light sensing unit, wherein the first transistor and the first light sensing unit are electrically connected; A second light detection unit, electrically connected to the first light detection unit, wherein the second light detection unit comprises a second light sensing unit and a second transistor, wherein the second light sensing unit and the second transistor are electrically connected; a driving transistor having a gate terminal, wherein the gate terminal is electrically connected to the first light sensing unit and the second light sensing unit, In a time interval, the first transistor is not turned on, and the second transistor is turned on, wherein the first transistor is controlled by a first signal, and the second transistor is controlled by a second signal, A control circuit, used for determining whether to allow the second signal to control the second transistor; as well as A feedback circuit, when the voltage at the gate terminal is a third voltage, the feedback circuit is used to determine whether the light detection element detects direct light, or when the voltage at the gate terminal is a fourth voltage, the feedback circuit is used to determine whether the light detection element detects reflected light. 2 . The light detecting element according to claim 1 , further comprising a light source, wherein the light source operates synchronously with the first transistor. 3 . The light detection element according to claim 1 , wherein one terminal of the first transistor is coupled to a first voltage, and one terminal of the second transistor is coupled to a second voltage, wherein a potential of the first voltage is different from a potential of the second voltage. The light detecting element according to claim 1 , wherein the control circuit comprises a readout circuit. 5 . The light detection element according to claim 1 , wherein when the feedback circuit determines that the light detection element detects the direct light, the control circuit enables the second signal to allow the second signal to control the second transistor to turn on. 6 . The light detecting element according to claim 1 , wherein when the feedback circuit determines that the light detecting element detects the reflected light, the control circuit disables the second signal so that the second signal controls the second transistor to be non-conductive.

Images