CN113611236B

CN113611236B - Photo sensing circuit

Info

Publication number: CN113611236B
Application number: CN202110491482.5A
Authority: CN
Inventors: 叶政忠; 李宗霖
Original assignee: Sitronix Technology Corp
Current assignee: Sitronix Technology Corp
Priority date: 2020-05-05
Filing date: 2021-05-06
Publication date: 2024-03-15
Anticipated expiration: 2041-05-06
Also published as: TW202201368A; TWI810556B; TW202333123A; CN113611236A

Abstract

The invention relates to a light sensing circuit which is applied to a display panel with a plurality of pixel structures, wherein each pixel structure comprises a transistor, the transistor is coupled with a gate line and a source line of the display panel, is controlled by a gate signal of the gate line and receives a source signal of the source line.

Description

Photo sensing circuit

Technical Field

The present invention relates to a sensing circuit, and more particularly, to a photo sensing circuit.

Background

The light sensing technology has been widely applied to many electronic devices, particularly to electronic products with display functions, such as mobile phones, tablet computers, and the like. The light sensing technology is commonly used for sensing the intensity (brightness) of ambient light so as to correspondingly adjust the brightness of the display screen of the display panel. Today, a photosensor is usually disposed in the electronic device, so as to increase the number of components of the electronic device. Related art today proposes to provide a light sensing circuit in a display panel, so that an additional light sensor is not required to be disposed in an electronic device. However, disposing the light sensing circuit in the display panel may reduce the pixel resolution of the display panel, even the Aperture Ratio (Aperture Ratio), and may affect the display quality.

Therefore, the present invention provides a light sensing circuit capable of sensing light by using the pixel structure of the display panel to solve the above-mentioned problems of the conventional art.

Disclosure of Invention

The present invention provides a light sensing circuit for detecting the electrical state of the pixel structure of the display panel to sense the intensity of light, so that the light sensing circuit is not required to be additionally arranged on the display panel, and the light sensor is not required to be additionally arranged on the electronic device, thereby saving the cost.

The invention discloses a light sensing circuit which is applied to a display panel with a plurality of pixel structures, wherein each pixel structure comprises a transistor, the transistor is coupled with a gate line and a source line of the display panel, is controlled by a gate signal of the gate line and receives a source signal of the source line, and the light sensing circuit comprises a detection circuit which detects an electrical state of the pixel structures so as to sense light.

Drawings

Fig. 1: the light sensing circuit is a schematic diagram of an embodiment of the invention applied to a display module;

fig. 2: the display panel is a schematic diagram of a pixel structure of the display panel;

fig. 3: the graph of capacitance versus storage voltage of the liquid crystal capacitor of the pixel structure of the invention;

Fig. 4: a circuit diagram of a second embodiment of the light sensing circuit of the present invention;

fig. 5: a circuit diagram of a third embodiment of the light sensing circuit of the present invention;

fig. 6: a circuit diagram of a fourth embodiment of the light sensing circuit of the present invention;

fig. 7: a circuit diagram of a fifth embodiment of the light sensing circuit of the present invention;

fig. 8: a schematic diagram of a first embodiment of the light sensing circuit of the present invention sensing the intensity of ambient light;

fig. 9: a schematic diagram of a second embodiment of the light sensing circuit of the present invention sensing the intensity of ambient light;

fig. 10: a schematic diagram of a third embodiment of the light sensing circuit of the present invention sensing the intensity of ambient light; and

fig. 11: a schematic diagram of an embodiment of a lookup table of the light sensing circuit of the present invention sensing the intensity of ambient light is shown.

[ figure number control description ]

10. Panel board

11. Gate line

13. Source line

15. Pixel structure

17. Transistor with a high-voltage power supply

20. Gate driving circuit

30. Source electrode driving circuit

40. Detection circuit

41. Sensing driving circuit

43. Receiving circuit

45. Disabling circuit

47. Control circuit

49. Judging circuit

A1 Region(s)

A2 Region(s)

A3 Region(s)

BL backlight region

C _GD Parasitic capacitance

C _ITO Parasitic capacitance

CL liquid crystal capacitor

COM common electrode

COM0 common electrode

COM1 common electrode

COM2 common electrode

COM3 common electrode

COM4 common electrode

COM5 common electrode

CS storage capacitor

C _SD Parasitic capacitance

Cur1 curve

Cur2 curve

G0-GN-1 grid line

I _L Electric current

Light

S0-SN-1 source line

VCOM_TX sense driving signal

VG 0-VGN-1 gate signals

VS 0-VSN-1 source signals

Detailed Description

For a further understanding and appreciation of the structural features and advantages achieved by the present invention, the following description is provided with reference to the preferred embodiments and in connection with the accompanying detailed description:

certain terms are used throughout the description and claims to refer to particular components, however, it should be understood by one of ordinary skill in the art that manufacturers may refer to a component by different names, and that the description and claims do not rely on differences in names to distinguish between components, but rather use differences in the technologies of the components as a whole. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. Furthermore, the term "coupled" as used herein includes any direct or indirect connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections.

Fig. 1 is a schematic diagram of an embodiment of a light sensing circuit applied to a display module according to the present invention. As shown in the drawings, the display module of the present invention comprises a panel 10, a gate driving circuit 20, and a source driving circuit 30. The panel 10 includes a plurality of gate lines 11 (G0-GN-1), a plurality of source lines 13 (S0-SN-1), and a plurality of pixel structures 15, wherein the gate lines 11 and the source lines 13 are staggered, the pixel structures 15 are positioned at the staggered position, and each pixel structure 15 includes a transistor 17, a liquid crystal capacitor CL and a storage capacitor CS. The gate and the source of the transistor 17 are coupled to the gate line 11 and the source line 13, respectively, the drain of the transistor 17 is coupled to a second end of the lc capacitor CL and a second end of the storage capacitor CS, a first end of the lc capacitor CL is coupled to a common electrode COM, and a first end of the storage capacitor CS is coupled to the common electrode COM or a ground terminal. The transistor 17 may be a Thin Film Transistor (TFT). The gate driving circuit 20 is coupled to the gate lines 11 and outputs a plurality of gate signals VG0, VG1 to VGN-1 to the gate lines 11, and the gate lines 11 respectively transmit the gate signals VG0, VG1 to VGN-1 to the gates of the transistors 17 of the pixel structures 15 in each row to control the transistors 17 of the pixel structures 15. The source driving circuit 30 is coupled to the source lines 13 and outputs a plurality of source signals VS0, VS 1-VSN-1 to the sources of the transistors 17 of the pixel structures 15 in each column, so as to charge the liquid crystal capacitors CL of the pixel structures 15 to drive the pixel structures 15 to display images.

The photo-sensing circuit of the present invention includes a detecting circuit 40 coupled to the source lines 13 to detect a current or a voltage of the source lines 13, so as to detect the electrical states of the pixel structures 15, so as to generate a plurality of photo-detection signals, wherein the photo-detection signals can represent the intensity (brightness) of the light. The light sensing circuit of the present invention is applied to the display panel 10 as follows. The light detection signals can be provided to a host, such as a microprocessor of the electronic device, so as to obtain the light intensity of the electronic device.

Fig. 2 is a schematic diagram of a pixel structure of the display panel of the present invention. The following description will be made with reference to the pixel structure 15 located at the intersection of the gate line G1 and the source line S1, and the remaining pixel structures 15 are the same. When the transistor 17 of the pixel structure 15 is turned off by the gate signal VG1 of the gate line G1, for example, the voltage level of the gate signal VG1 is low, such that the voltage difference between the gate and the source of the transistor 17 is smaller than the threshold voltage of the transistor 17, and a current I is still present between the source and the drain of the transistor 17 _L Current I _L Through the source and drain of transistor 17, current I _L Is the leakage current of transistor 17. Current I _L Is proportional to the intensity of the Light, the higher the intensity of the Light, the current I _L The larger the current I _L May be referred to as photocurrent. Therefore, the intensity of the Light can be sensed by using the electrical characteristics of the transistor 17 of the pixel structure 15. Due to current I _L Through the source of transistor 17, it will also flow on source line S1, so that detection circuit 40 detects the current of source line S1, i.e., corresponding to detection current I _L And can generate a detection signal to sense the intensity of the Light. In addition, since the voltage of the source line S1 is proportional to the current, the detection circuit 40 detects the voltage of the source line S1, i.e. the detection current I _L But also the intensity of the Light. In addition, the detection circuit 40 may also be coupled to the transistor 17 of the pixel structure 15 to directly detect the current I _L And generates a detection signal to sense the intensity of the Light.

The current I is connected with the above _L The flow direction of (a) is determined by the voltage of the source and the voltage of the drain of the transistor 17, and when the voltage of the source of the transistor 17 is larger than the voltage of the drain, the current I _L The liquid crystal capacitor CL is charged by flowing from the source to the drain of the transistor 17; when the voltage at the source of transistor 17 is smaller than the voltage at the drain, current I _L From the drain to the source of transistor 17, i.e. the liquid crystal capacitor CL discharges, and a current I _L The magnitude of (c) affects the rate of charge and discharge of the lc capacitor CL. Therefore, in another embodiment of the present invention, the detection circuit 40 can be coupled to the pixel structure 17 and detect the storage voltage of the liquid crystal capacitor CL to generate a detection signal for sensing the intensity of the Light.

Please refer to fig. 3, which is a graph of capacitance versus storage voltage of the liquid crystal capacitor of the pixel structure of the present invention. As shown, the curve CUR1 shows the relative relationship between the storage voltage of the liquid crystal capacitor CL and the relative transmittance of the Light passing through the display panel 10. As can be seen from the curve CUR1, the storage voltage affects the relative transmittance, and the higher the storage voltage, the lower the relative transmittance, i.e. the lower the brightness of the display panel 10. Curve CUR2 is the capacitance of the lc capacitor CL versus the storage voltage. As can be seen from the curve CUR2, the storage voltage of the liquid crystal capacitor CL affects the capacitance of the liquid crystal capacitor CL, and the capacitance is proportional to the storage voltage when the storage voltage is between about 1 volt and 5 volts. Based on this characteristic, in another embodiment of the present invention, the detection circuit 40 may be coupled to the pixel structure 17 and detect the capacitance of the liquid crystal capacitor CL to generate a detection signal for sensing the intensity of the Light. The curves CUR1 and CUR2 in fig. 3 are only characteristic curves of an embodiment of the display panel 10 of the present invention, and different display panels 10 may have different characteristic curves, and the curves CUR1 and CUR2 in fig. 3 are only for illustration and not limitation.

Based on the characteristic that the capacitance of the liquid crystal capacitor CL varies with the storage voltage, by providing a sensing driving signal vcom_tx (as shown in fig. 4 to 7) to the common electrode COM (as shown in fig. 1) coupled to the first end of the liquid crystal capacitor CL, the voltage level of the second end of the liquid crystal capacitor CL varies, and the ratio of the variation is directly related to the capacitance of the liquid crystal capacitor CL. Therefore, the voltage level at the second end of the lc capacitor CL is related to the intensity of the Light. In an embodiment of the present invention, the detection circuit 40 can detect the voltage level of the second end of the lc capacitor CL to generate the Light detection signal for sensing the intensity of the Light. In addition, the voltage level of the drain of the transistor 17 is equal to the voltage level of the second end of the liquid crystal capacitor CL, and a parasitic capacitor C is arranged between the source and the drain of the transistor 17 _SD Therefore, the voltage level of the second end of the liquid crystal capacitor CL affects the voltage level of the signal of the source line S1, and the signal of the source line S1 is a source sensing signal, which is generated corresponding to the sensing driving signal vcom_tx, so that the voltage level of the source sensing signal of the source line S1 can be detected, which is equivalent to the voltage level of the second end of the liquid crystal capacitor CL, so as to sense the intensity of the Light. A parasitic capacitor C is arranged between the source of the transistor 17 and the first end of the liquid crystal capacitor CL _ITO Parasitic capacitance C _ITO The parasitic capacitance between the source line S1 and the common electrode COM has a small capacitance, so that the voltage level of the source sensing signal affecting the source line S1 is limited. In an embodiment of the present invention, the sensing driving signal vcom_tx may include at least one pulse, where the level of the pulse includes a high level and a low level.

In addition, as shown in FIG. 2, a parasitic capacitance C is provided between the gate and the drain of the transistor 17 _GD The voltage level of the second end of the liquid crystal capacitor CL affects the voltage of the gate line G1The signal of the gate line G1 is a gate sensing signal, which is generated corresponding to the sensing driving signal vcom_tx, so that the voltage level of the gate sensing signal of the gate line G1 is detected, which is equivalent to the voltage level of the second end of the liquid crystal capacitor, so as to sense the intensity of the Light. A parasitic capacitor C is arranged between the gate of the transistor 17 and the first end of the liquid crystal capacitor CL _ITO This parasitic capacitance C _ITO The parasitic capacitance between the gate line G1 and the conductive line of the common electrode COM is small, so that the voltage level of the gate sensing signal affecting the gate line G1 is limited. The detection circuit 40 can detect the current of the source line 13, the voltage of the source line 13, and the current I of the transistor 17 _L The storage voltage of the liquid crystal capacitor CL, the capacitance of the liquid crystal capacitor CL, the gate sensing signal of the gate line 11 or the source sensing signal of the source line 13, that is, the electrical state of the pixel structure 15 is detected, so as to generate the Light detection signal, and since the electrical state of the pixel structure 15 varies with the intensity of the Light, the electrical state of the pixel structure 15 is detected, so that the intensity of the Light can be sensed. The following exemplary embodiment provides the sensing driving signal vcom_tx to the common electrode VOM, and detects the gate sensing signals of the gate lines 11 and the source sensing signals of the source lines 13 to sense the intensity of the Light.

Please refer to fig. 4, which is a circuit diagram of a second embodiment of the photo sensing circuit of the present invention. As shown, the photo-sensing circuit includes a sensing driving circuit 41 and a detecting circuit. The sensing driving circuit 41 is coupled to the common electrode COM of the display panel 10, and generates a sensing driving signal vcom_tx to the common electrode COM. In an embodiment of the present invention, the display panel 10 includes only a single common electrode COM, and corresponds to all the pixel structures 15. In an embodiment of the invention, the sensing driving circuit 41 may be a common voltage generating circuit, which generates the sensing driving signal vcom_tx to the common electrode COM in a light sensing period, and generates a display common voltage vcom_dsp to the common electrode COM in a display period to drive the pixel structures 15 to display images in cooperation with the source signals VS0, VS 1-VSN-1.

The embodiment is exemplified by 6 gate lines G0 to G5 and 8 source lines S0 to S7, but not limited thereto. The detection circuit includes a plurality of receiving circuits 43 and a plurality of disabling circuits 45, and the receiving circuits 43 and the disabling circuits 45 are respectively coupled to the gate lines G0 to G5 and the source lines S0 to S7. In one embodiment of the present invention, each of the gate lines G0-G5 and each of the source lines S0-S7 are respectively coupled to a receiving circuit 43 and a disabling circuit 45, i.e. the detecting circuit is coupled to the gate lines G0-G5 and the source lines S0-S7. The receiving circuits 43 coupled to the gate lines G0 to G5 receive the gate sensing signals via the gate lines G0 to G5, and the receiving circuits 43 coupled to the source lines S0 to S7 receive the source sensing signals via the source lines S0 to S7.

Referring to fig. 4 again, the disabling circuits 45 are configured to disable the gate lines G0 to G5 and the source lines S0 to S7 to drive at least one gate line G0 to G5 or/and at least one source line S0 to S7 to be in a disabled state without the gate sensing signal or/and the source sensing signal. In one embodiment of the present invention, the disable circuit 45 provides a DC level to at least one gate line G0-G5 or/and at least one source line S0-S7, wherein the DC level includes a ground level to drive the gate lines G0-G5/the source lines S0-S7 not to generate the gate sensing signal/the source sensing signal. In addition, the disabling circuit 45 can drive the impedance of at least one gate line G0 to G5 or/and at least one source line S0 to S7 to be high, and is in a floating state, so that the gate lines G0 to G5/the source lines S0 to S7 can be driven to generate no gate sensing signal/no source sensing signal. In an embodiment of the present invention, the disabling circuits 45 may be integrated into a single disabling circuit, so as to selectively disable at least one gate line G0 to G5 and/or at least one source line S0 to S7 to generate the sensing signal. The detection circuit of the present invention may further comprise a control circuit 47 coupled to the receiving circuits 43 and the disabling circuits 45 to control the operations of the receiving circuits 43 and the disabling circuits 45. In addition, a judging circuit 49 is further included, which is coupled to the receiving circuits 43 and receives the gate sensing signals and the source sensing signals, and generates a Light detection signal according to the gate sensing signals and the source sensing signals to sense the intensity of the Light. The sensing driving circuit 41, the judging circuit 49 and the detecting circuit may be integrated on the same chip, but are not limited thereto. For example, the determining circuit 49 may be located on a host, such as a microprocessor of an electronic device.

Please refer to fig. 5, which is a circuit diagram of a third embodiment of the photo sensing circuit of the present invention. As shown in the figure, the difference between the embodiment and the embodiment of fig. 4 is that the gate lines G0-G5 are grouped into a plurality of gate line groups, which include a first gate line group including the gate lines G0-G2 and a second gate line group including the gate lines G3-G5, and the embodiment uses 3 gate lines as a gate line group, but not limited thereto. In addition, the source lines S0 to S7 are grouped into a plurality of source line groups, which include a first source line group, a second source line group, a third source line group and a fourth source line group, wherein the first source line group includes source lines S0 to S1, the second source line group includes source lines S2 to S3, the third source line group includes source lines S4 to S5, and the fourth source line group includes source lines S6 to S7, and the embodiment uses 2 source lines as a source line group but is not limited thereto. Each gate line group and each source line group are respectively coupled to a receiving circuit 43 and a disabling circuit 45, so that the number of the receiving circuits 43 and the disabling circuits 45 can be reduced, the coupling area of the common electrode COM can be increased, and the strength of the sensing signal can be improved. The embodiment of fig. 4 uses 1 gate line as a gate line group and 1 source line as a source line group.

In the following description of the detection mode of the photo sensing circuit in the embodiment of fig. 5, first, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the first source line group (source lines S0 to S1) to receive the first source sensing signal via the first source line group and transmit the first source sensing signal to the judging circuit 49, and meanwhile, the control circuit 47 controls the disabling circuit 45 coupled to the second (source lines S2 to S3), the third (source lines S4 to S5) and the fourth (source lines S6 to S7) source line groups to drive the second, third and fourth source line groups to be in a disabled state, and the control circuit 47 also controls the disabling circuit 45 coupled to the first (gate lines G0 to G2) and the second (gate lines G3 to G5) gate line groups to drive the first and second gate line groups to be in a disabled state; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the second source line group to receive the second source sensing signal via the second source line group and transmit the second source sensing signal to the judging circuit 49, and the control circuit 47 controls the disabling circuit 45 coupled to the first, third and fourth source line groups to drive the first, third and fourth source line groups to be in a disabled state, while the first and second gate line groups remain in a disabled state; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the third source line group to receive the third source sensing signal via the third source line group and transmit the third source sensing signal to the judging circuit 49, and the control circuit 47 controls the disabling circuit 45 coupled to the first, second and fourth source line groups to drive the first, second and fourth source line groups to be in a disabled state, and the first and second gate line groups are kept in a disabled state; next, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the fourth source line group to receive the fourth source sensing signal via the fourth source line group and transmit the fourth source sensing signal to the determining circuit 49, and the control circuit 47 controls the disabling circuit 45 coupled to the first, second and third source line groups to drive the first, second and third source line groups to be in a disabled state, and the first and second gate line groups are kept in a disabled state. Thus, the determining circuit 49 can detect the intensity of the Light irradiated on the source line group, and locate the intensity of the Light with the first direction dimension.

Next, the sensing driving circuit 41 provides a sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the first gate line group to receive the first gate sensing signal via the first gate line group and transmit the first gate sensing signal to the judging circuit 49, and at the same time, the control circuit 47 controls the disabling circuit 45 coupled to the second gate line group to drive the second gate line group to be in a disabled state, and the control circuit 47 also controls the disabling circuit 45 coupled to the first to fourth source line groups to drive the first to fourth source line groups to be in a disabled state; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the second gate line group to receive the second gate sensing signal via the second gate line group and transmit the second gate sensing signal to the judging circuit 49, and the control circuit 47 controls the disabling circuit 45 coupled to the first gate line group to drive the first gate line group to be in a disabled state, and the first to fourth source line groups are kept in a disabled state. Thus, the determining circuit 49 can detect the intensity of the Light irradiated on the gate line group, and locate the intensity of the Light with the second direction dimension. In one embodiment, the plurality of source sensing signals may be simultaneously received through the plurality of source line groups or the plurality of gate sensing signals may be simultaneously received through the plurality of gate line groups.

In addition, if the position of the Light with stronger or weaker intensity needs to be precisely located, the following steps can be further performed according to the combination of the source line group and the gate line group irradiated by the Light with stronger or weaker intensity determined as described above. It is assumed that the intensity of Light irradiated to the first, third, first, and second gate line groups is weak. The sensing driving circuit 41 provides a sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the first source line group to receive the first source sensing signal via the first source line group and transmit the first source sensing signal to the judging circuit 49, and the control circuit 47 also controls the receiving circuit 43 coupled to the first gate line group to receive the first gate sensing signal via the first gate line group and transmit the first gate sensing signal to the judging circuit 49, wherein the rest source line groups and the Yu Shan line groups are in a disabled state, and if the judging circuit 49 judges that the voltage level of the first source sensing signal and the voltage level of the first gate sensing signal are weaker than the weaker Light, the intersection area of the first source line group and the first gate line group is the weaker Light real irradiation area. Then, the control circuit 47 controls the receiving circuit 43 coupled to the first source line group to receive the first source sensing signal via the first source line group, and the control circuit 47 also controls the receiving circuit 43 coupled to the second gate line group to receive the second gate sensing signal via the second gate line group, and the other source line groups and Yu Shan line groups are all in a disabled state; then, the control circuit 47 controls the receiving circuit 43 coupled to the third source line group to receive the third source sensing signal via the third source line group, and the control circuit 47 also controls the receiving circuit 43 coupled to the first gate line group to receive the first gate sensing signal via the first gate line group, and the other source line groups and Yu Shan line groups are all in a disabled state; finally, the control circuit 47 controls the receiving circuit 43 coupled to the third source line group to receive the third source sensing signal via the third source line group, and the control circuit 47 also controls the receiving circuit 43 coupled to the second gate line group to receive the second gate sensing signal via the second gate line group, and the other source line groups and Yu Shan line groups are all in a disabled state. Thus, the judging circuit 49 can judge all the real irradiation areas of the weaker Light.

Another detection method of the photo-sensing circuit is described in the embodiment of fig. 5. The sensing driving circuit 41 provides a sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the first source line group to receive the first source sensing signal via the first source line group and transmit the first source sensing signal to the judging circuit 49, and the control circuit 47 also controls the receiving circuit 43 coupled to the first gate line group to receive the first gate sensing signal via the first gate line group and transmit the first gate sensing signal to the judging circuit 49, wherein the other source line groups and Yu Shan line groups are in a disabled state; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the first source line group to receive the first source sensing signal via the first source line group and transmit the first source sensing signal to the judging circuit 49, and the control circuit 47 also controls the receiving circuit 43 coupled to the second gate line group to receive the second gate sensing signal via the second gate line group and transmit the second gate sensing signal to the judging circuit 49, wherein the other source line groups and Yu Shan line groups are in a disabled state; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the second source line group to receive the second source sensing signal via the second source line group and transmit the second source sensing signal to the judging circuit 49, and at the same time, the control circuit 47 also controls the receiving circuit 43 coupled to the first gate line group to receive the first gate sensing signal via the first gate line group and transmit the first gate sensing signal to the judging circuit 49, and the other source line groups and Yu Shan line groups are all in a disabled state; in turn, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the common electrode COM, the control circuit 47 controls the receiving circuit 43 coupled to the second source line group to receive the second source sensing signal via the second source line group and transmit the second source sensing signal to the judging circuit 49, and the control circuit 47 also controls the receiving circuit 43 coupled to the second gate line group to receive the second gate sensing signal via the second gate line group and transmit the second gate sensing signal to the judging circuit 49, wherein the other source line groups and Yu Shan line groups are disabled. Similarly, the third source sensing signal and the first gate sensing signal are received through the third source line group and the first gate line group at the same time; then, a third source sensing signal and a second gate sensing signal are received through the third source line group and the second gate line group at the same time; then, receiving a fourth source sensing signal and a first gate sensing signal through the fourth source line group and the first gate line group at the same time; finally, a fourth source sensing signal and a second gate sensing signal are received through the fourth source line group and the second gate line group at the same time.

Please refer to fig. 6, which is a circuit diagram of a fourth embodiment of the photo sensing circuit of the present invention. As shown, this embodiment includes a plurality of common electrodes COM 0-COM 5, unlike the embodiment of FIG. 4 which includes only a single common electrode COM. The common electrodes COM0 to COM5 cross the source lines S0 to S7, and the sensing driving circuit 41 is coupled to the common electrodes COM0 to COM5 to provide a sensing driving signal vcom_tx to the common electrodes COM0 to COM5 or drive at least one of the common electrodes COM0 to COM5 to be in a disabled state. The sense driving circuit 41 can provide a dc level to at least one common electrode COM0 to COM5 or drive at least one common electrode COM0 to COM5 to be floating as the disabling circuit 45 so as to drive the common electrodes COM0 to COM5 to be in a disabled state. In addition, the gate lines G0-G5 of this embodiment are not coupled to the receiving circuit 43 and the disabling circuit 45. The number of common electrodes is determined according to the use requirement, and is not limited to a specific number.

Please refer to fig. 7, which is a circuit diagram of a fifth embodiment of the photo sensing circuit of the present invention. As shown, this embodiment differs from the embodiment of fig. 5 in that this embodiment includes a plurality of common electrodes COM0 to COM5, and differs from the embodiment of fig. 5 in that only a single common electrode COM is included. In addition, the gate lines G0-G5 of this embodiment are not coupled to the receiving circuit 43 and the disabling circuit 45.

Another detection method of the photo-sensing circuit is described in the embodiment of fig. 7. The sensing driving circuit 41 provides a sensing driving signal vcom_tx to the first common electrode COM0, and drives the second to sixth common electrodes COM1 to COM5 to be in a disabled state, and the control circuit 47 controls the receiving circuit 43 coupled to the first to fourth source line groups to receive the first to fourth source sensing signals via the first to fourth source line groups, and sends the signals to the judging circuit 49, so as to judge whether the real illumination area of the weak or strong Light is the intersection area of the first common electrode COM0 and the first to fourth source line groups. Next, the sensing driving circuit 41 provides a sensing driving signal vcom_tx to the second common electrode COM1, and drives the first common electrode COM0 and the third to sixth common electrodes COM2 to COM5 to be in a disabled state, and the control circuit 47 controls the receiving circuit 43 coupled to the first to fourth source line groups to receive the first to fourth source sensing signals through the first to fourth source line groups and transmit the signals to the judging circuit 49. Similarly, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the third common electrode COM2, and drives the first to second common electrodes COM0 to COM1, the fourth to sixth common electrodes COM3 to COM5 to be in a disabled state, and receives the first to fourth source sensing signals through the first to fourth source line groups; afterwards, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the fourth common electrode COM3, and drives the first to third common electrodes COM0 to COM2, the fifth to sixth common electrodes COM4 to COM5 to be in a disabled state, and receives the first to fourth source sensing signals through the first to fourth source line groups; then, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the fifth common electrode COM4, and drives the first to fourth common electrodes COM0 to COM3 and the sixth common electrode COM5 to be in a disabled state, and receives the first to fourth source sensing signals through the first to fourth source line groups; finally, the sensing driving circuit 41 provides the sensing driving signal vcom_tx to the sixth common electrode COM5, and drives the first to fifth common electrodes COM0 to COM4 to be in the disabled state, and receives the first to fourth source sensing signals through the first to fourth source line groups. The order of providing the sensing driving signal vcom_tx to the common electrodes COM0 to COM5 is just an embodiment of the invention, and is not limited thereto, and can be determined according to the requirement.

In addition, in another embodiment of the present invention, the common electrodes COM0 to COM5 may cross the gate lines, and the gate lines are used as sensing lines, so that the real illumination area of the weak or strong Light can be detected by the above method. As can be seen from the above description, the light sensing circuit of the present invention can be applied to sensing the intensity of the ambient light, touch detection or fingerprint identification.

Fig. 8 is a schematic diagram showing a first embodiment of the light sensing circuit for sensing the intensity of ambient light. The display panel 10 of this embodiment has three areas A1, A2, A3, the backlight module (not shown) only provides backlight to the area A3, and BL in the drawing indicates the backlight area, so the area A3 is the display area. The area A1 is a covering area, which is not irradiated by the ambient light, and both the area A2 and the area A3 are irradiated by the ambient light. By means of the light sensing circuit of the present invention, the electrical states of the pixel structures 15 located in the areas A1, A2, A3 can be detected respectively, the electrical states of the pixel structures 15 in the area A1 can represent no ambient light and no backlight, the electrical states of the pixel structures 15 in the area A2 can represent ambient light and no backlight, and the electrical states of the pixel structures 15 in the area A3 can represent backlight and ambient light. Thus, by comparing the electrical state of the pixel structure 15 of the area A1 with the electrical state of the pixel structure 15 of the area A2, the current intensity of the ambient light can be obtained. For example, the voltage of the source line 13 of the area A1 and the voltage of the source line 13 of the area A2 are subtracted, and the resulting voltage difference may represent the intensity of the ambient light.

Fig. 9 is a schematic diagram showing a second embodiment of the light sensing circuit for sensing the intensity of ambient light. The display panel 10 of this embodiment has two areas A1 and A3, and the backlight module provides backlight to the areas A1 and A3, BL in the illustration represents the backlight area, and the area A3 is the display area. The area A1 is a covered area, which is not irradiated with the ambient light, and the area A3 is irradiated with the ambient light. By means of the light sensing circuit of the present invention, the electrical states of the pixel structures 15 located in the areas A1 and A3 can be detected respectively, the electrical states of the pixel structures 15 in the area A1 can be represented by the backlight and the ambient light, and the electrical states of the pixel structures 15 in the area A3 can be represented by the backlight and the ambient light. Thus, by comparing the electrical state of the pixel structure 15 of the area A1 with the electrical state of the pixel structure 15 of the area A3, the current intensity of the ambient light can be obtained. For example, the voltage of the source line 13 of the area A1 is subtracted from the voltage of the source line 13 of the area A3, and the resulting voltage difference indicates the intensity of the ambient light.

Fig. 10 is a schematic diagram showing a third embodiment of the light sensing circuit for sensing the intensity of ambient light. The display panel 10 of this embodiment has an area A1, the backlight module provides backlight to the area A1, BL in the icon represents the backlight area, and the area A1 is exposed to ambient light to be the display area. The electrical state of the pixel structure 15 of the region A1 can be detected in advance under the known different intensity backlight and the known different intensity ambient light by the light sensing circuit of the present invention, so as to build the lookup table as shown in fig. 11. Then, since the intensity of the backlight is known, the light sensing circuit can know the intensity of the ambient light according to the detected electrical state of the pixel structure 15 and the lookup table. If the electrical state obtained by the light sensing circuit is not in the lookup table, the intensity of the ambient light can be estimated through interpolation or extrapolation. For example, the intensity of the backlight is known to be 2, and the voltage of the source line 13 obtained by the light sensing circuit is between vrx_b2_e1 and vrx_b2_e2, so that the intensity of the ambient light is known to be between 1 and 2, and if the intensity is known more precisely, the more precise intensity of the ambient light can be estimated by interpolation operation. The operation described in the embodiments of fig. 8 to 10 can be performed by the determination circuit 49 of the embodiment, but is not limited thereto.

In summary, the light sensing circuit of the present invention detects the electrical state of the pixel structure by using the pixel structure of the display panel, so as to sense the intensity of light, and thus, the light sensing circuit is not required to be additionally arranged on the display panel, and the light sensor is not required to be additionally arranged on the electronic device, thereby saving the cost.

The foregoing description of the preferred embodiments of the present invention is not intended to limit the scope of the invention, but rather to cover all equivalent variations and modifications in shape, construction, characteristics and spirit according to the scope of the present invention as defined in the appended claims.

Claims

1. The light sensing circuit is applied to a display panel with a plurality of pixel structures, each pixel structure comprises a transistor, the transistor is coupled with a gate line and a source line of the display panel, is controlled by a gate signal of the gate line and receives a source signal of the source line, and the light sensing circuit comprises:

a detection circuit for detecting an electrical state of the pixel structures to sense light; and

a sensing driving circuit for generating a sensing driving signal and providing the signal to at least one common electrode of the display panel;

The detection circuit detects a plurality of source sensing signals through the source lines so as to detect the electrical state of the pixel structures, wherein the source sensing signals are generated corresponding to the sensing driving signals.

2. The light-sensing circuit of claim 1, wherein the electrical state of the pixel structures varies with the brightness of a light.

3. The light-sensing circuit of claim 1, wherein the detection circuit detects a current of the transistors of the pixel structures to sense light.

4. The light-sensing circuit of claim 1, wherein the detection circuit detects a current of the source lines to detect the electrical state of the pixel structures.

5. The light-sensing circuit of claim 1, wherein the detection circuit detects a voltage of the source lines to detect the electrical state of the pixel structures.

6. The light-sensing circuit of claim 1, wherein each of the pixel structures further comprises a capacitor coupled to the transistor, the detection circuit detecting a storage voltage of the capacitors of the pixel structures to detect the electrical state of the pixel structures.

7. The light-sensing circuit of claim 1, wherein each of the pixel structures further comprises a capacitor coupled to the transistor, the detection circuit detecting a capacitance of the capacitors of the pixel structures to detect the electrical state of the pixel structures.

8. The light-sensing circuit of claim 1, wherein the detection circuit detects a plurality of gate-sensing signals via the gate lines to detect the electrical states of the pixel structures, the gate-sensing signals being generated in response to the sensing driving signals.

9. The light sensing circuit of claim 8, wherein the source lines are grouped into a plurality of source line groups, each source line group comprises at least one source line, the source line groups comprise a first source line group and a second source line group, the gate lines are grouped into a plurality of gate line groups, each gate line group comprises at least one gate line, the gate line groups comprise a first gate line group and a second gate line group, the sense driving circuit provides the sense driving signal to the common electrode during a first period, the sense driving circuit receives a first source sensing signal of the source sensing signals via the first source line group and drives the remaining source line groups and the gate line groups to be in a disabled state; in a second period, the sensing driving circuit provides the sensing driving signal to the common electrode, and the detecting circuit receives a second source sensing signal of the source sensing signals through the second source line group and drives the rest source line groups and the gate line groups to be in the disabled state.

10. The light sensing circuit of claim 9, wherein during a third period, the sense driving circuit provides the sense driving signal to the common electrode, the detection circuit receives a first gate sensing signal of the gate sensing signals via the first gate line group and drives the remaining gate line groups and the source line groups to be in the disabled state; in a fourth period, the sensing driving circuit provides the sensing driving signal to the common electrode, and the detecting circuit receives a second gate sensing signal of the gate sensing signals through the second gate line group and drives the rest gate line groups and the source line groups to be in the disabled state.

11. The light-sensing circuit of claim 9, wherein the detection circuit provides a dc level to the remaining source line groups and the gate line groups to drive the remaining source line groups and the gate line groups in the disabled state.

12. The light-sensing circuit of claim 11, wherein the dc level comprises a ground level.

13. The light-sensing circuit of claim 9, wherein the detection circuit drives the remaining source line groups and the gate line groups to be floating and drives the remaining source line groups and the gate line groups to be in the disabled state.

14. The light sensing circuit of claim 9, wherein the detection circuit comprises a plurality of receiving circuits coupled to the source line groups and the gate line groups, receiving the source sensing signals and the gate sensing signals, and at least one disabling circuit coupled to the source line groups and the gate line groups, disabling the remaining source line groups and the gate line groups.

15. The light sensing circuit of claim 8, wherein the source line groups are a plurality of source line groups, each source line group comprises at least one source line, the source line groups comprise a first source line group and a second source line group, the gate lines groups are a plurality of gate line groups, each gate line group comprises at least one gate line, the gate line groups comprise a first gate line group and a second gate line group, the sense driving circuit provides the sense driving signal to the common electrode during a first period, the detection circuit receives a first source sensing signal of the source sensing signals and a first gate sensing signal of the gate sensing signals via the first gate line group, and drives the remaining source line groups and Yu Shan line groups to be in a disabled state; in a second period, the sensing driving circuit provides the sensing driving signal to the common electrode, and the detecting circuit receives the first source sensing signal via the first source line group and receives a second gate sensing signal of the gate sensing signals via the second gate line group and drives the rest source line groups and the Yu Shan line group to be in the disabled state.

16. The light sensing circuit of claim 15, wherein during a third period, the sense driving circuit provides the sense driving signal to the common electrode, the detection circuit receives a second source sensing signal of the source sensing signals via the second source line group and receives the first gate sensing signal via the first gate line group, and drives the remaining source line groups and their Yu Shan line groups to be in the disabled state; in a fourth period, the sensing driving circuit provides the sensing driving signal to the common electrode, and the detecting circuit receives the second source sensing signal via the second source line group and the second gate sensing signal via the second gate line group and drives the rest of the source line groups and the Yu Shan line groups to be in the disabled state.

17. The light-sensing circuit of claim 15, wherein the detection circuit comprises a plurality of receiving circuits coupled to the source line groups and the gate line groups, receiving the source sensing signals and the gate sensing signals, and at least one disabling circuit coupled to the source line groups and the gate line groups, disabling the remaining source line groups and the remaining gate line groups.

18. The light sensing circuit of claim 1, wherein the at least one common electrode comprises a first common electrode and a second common electrode, the first common electrode and the second common electrode intersect the source lines, the source lines are grouped into a plurality of source line groups, each source line group comprises at least one source line, the sense driving circuit provides the sense driving signal to the first common electrode and drives the second common electrode to be in a disabled state during a first period, and the detection circuit receives the source sensing signals through the source line groups; in a second period, the sensing driving circuit provides the sensing driving signal to the second common electrode and drives the first common electrode to be in the disabled state, and the detecting circuit receives the source sensing signals through the source line groups.

19. The light-sensing circuit of claim 18, wherein the sense driver circuit provides a dc level to the first common electrode or the second common electrode to drive the first common electrode or the second common electrode to the disabled state.

20. The light-sensing circuit of claim 19, wherein the dc level comprises a ground level.

21. The light-sensing circuit of claim 18, wherein the sense driver circuit drives the first common electrode or the second common electrode to be floating and drives the first common electrode or the second common electrode to be in the disabled state.

22. The light-sensing circuit of claim 1, further comprising:

a sensing driving circuit for generating a sensing driving signal and providing the sensing driving signal to a common electrode of the display panel;

each pixel structure further comprises a capacitor coupled between the transistor and the common electrode, and the detection circuit detects a voltage level of the capacitors of the pixel structures to detect the electrical state of the pixel structures.

23. The light sensing circuit is applied to a display panel with a plurality of pixel structures, each pixel structure comprises a transistor, the transistor is coupled with a gate line and a source line of the display panel, is controlled by a gate signal of the gate line and receives a source signal of the source line, and the light sensing circuit comprises:

the detection circuit detects a plurality of gate sensing signals through the gate lines so as to detect the electrical state of the pixel structures, wherein the gate sensing signals are generated corresponding to the sensing driving signals.