TWI817785B - Light detecting component and detecting panel - Google Patents

Abstract

A light detecting component and a detecting panel including a plurality of light detecting components are provided. The light detecting component includes a light detecting circuit, a detecting transistor, and a reading transistor. In a luminance duration, the light detecting circuit detects a luminance strength, and a voltage of a detecting terminal is changed according to the luminance strength. In a luminance strength detecting duration, the detecting transistor changes a voltage of a luminance strength detecting signal in response to the voltage of the detecting terminal. In a compensation duration, a voltage of a main scan line is selectively changed with the voltage of a luminance strength detecting signal. In a reading duration, the reading transistor is conducted according to a pulse of the main scan line so that a reading line reflects the voltage of the detecting terminal. The luminance strength detecting duration is later than the luminance duration, the compensation duration is later than the luminance strength detecting duration, and the reading duration is later than the compensation duration.

Description

Light sensing components and sensing panels

The present invention relates to a light sensing element and a sensing panel, and in particular, to a light sensing element and a sensing panel with illumination compensation function.

With the evolution of digital technology, X-ray diagnostic photography has also advanced to digital methods. Please refer to Figure 1, which is a schematic diagram of the light sensing system for taking X-ray shots of a subject. The light sensing system 10 includes: a light source 11, a controller 15, a display panel 17 and a sensing panel 13. When taking pictures, the subject 14 is located in front of the sensing panel 13, and the light source 11 emits X-rays. The sensing panel 13 behind the subject 14 includes a plurality of light sensing units (light sensing units) arranged in an array. With the distribution of human tissue, the light intensity of the light sensing elements is not exactly the same. Then, the controller 15 reads the circuit characteristics of the light sensing element after being affected by light, and converts it into image data imgDAT using an image processing method. After the controller 15 transmits the image data imgDAT to the display panel 17 , the user can view the image on the display panel 17 .

Please refer to Figure 2, which is a schematic diagram of the light sensing element on the sensing panel. For ease of explanation, this article represents the position of the light sensing element in coordinate format. It is assumed here that the sensing panel 13 includes light sensing elements lgtSU(1,1)˜lgtSU(M,N) arranged in M rows and N columns. Among them, M and N are Positive integer. The light sensing elements lgtSU(1,1)~lgtSU(M,1) are located in the first column, arranged along the x-axis direction; the sensing elements lgtSU(1,1)~lgtSU(1,N) are located in the first row, arranged along the arranged in the y-axis direction.

As the body tissue distribution of the subject 14 is different, the blocking intensity of the light generated by the light source 11 is also different, and the light receiving intensity of the light sensing elements lgtSU(1,1)~lgtSU(M,N) is also different. . If the light sensing elements lgtSU(1,1)~lgtSU(M,N) are overexposed, the leakage current inside the light sensing elements lgtSU(1,1)~lgtSU(M,N) will increase, and then Affects the correctness of image data imgDAT.

For the convenience of explanation, this article assumes that the image restored based on the image data imgDAT contains M*N pixels PXL(1,1)~PXL(M,N), that is, each pixel PXL(1,1)~PXL(M ,N) corresponds to the sensing result of a light sensing element lgtSU(1,1)~lgtSU(M,N).

Please refer to Figure 3, which is a schematic diagram of the image restored by the display panel based on the image data imgDAT under ideal conditions when a certain area in front of the sensing panel is overexposed. Ideally, when a certain area is located in front of the sensing panel 13 (for example, the range corresponding to the light sensing elements lgtSU (X1, Y1) ~ lgtSU (X2, Y2)), the X-ray light penetrates the tissue When the ratio is higher, the image 23 displayed by the display panel 17 according to the image data imgDAT should appear as a blank area 23a. It is assumed here that the blank area 23a covers P*Q pixels PXL(X1, Y1)~PXL(X2, Y2) located in rows X1~X2 (P rows in total) and columns Y1~Y2 (Q columns in total).

Please refer to Figure 4A, which is a schematic diagram showing that when a certain area in front of the sensing panel is overexposed and leakage current occurs, the brightness of some areas in the image displayed based on the image data using conventional technology is disturbed. Comparing Figures 3 and 4A, it can be seen that according to conventional technology, if the position in front of the sensing panel 13 corresponding to the blank area 23a is more easily penetrated by light due to the tissue distribution of the subject 14, this range The light sensing elements lgtSU(X1,Y1)~lgtSU(X2,Y2) at the corresponding position can The leakage current may become larger. As the leakage current of the light sensing elements lgtSU(X1,Y1)~lgtSU(X2,Y2) becomes larger, the controller 15 cannot ) to obtain accurate image data imgDAT, so that the image 25 shown in Figure 4A includes a blank block 25a and a disturbed block 25c. That is, in addition to the light sensing elements in the range corresponding to the actual overexposure phenomenon, other light sensing elements located in the same number of rows (rows X1~X2) but different numbers of columns (columns 1~(Y1-1)) , although overexposure does not occur, the sensing results produced are still affected by leakage current. Connectedly, using the slave image 25, one will see that the brightness of the disturbed area 25c is incorrect.

Please refer to Figure 4B, which is a schematic diagram of improving the image in Figure 4A by reducing the sensitivity of the light sensing element in conventional technology. In order to prevent the light sensing elements lgtSU(X1,Y1)~lgtSU(X2,Y2) from generating leakage current and affecting the sensing results of other light sensing elements, a common technical approach is to reduce the sensitivity of the light sensing elements. When the sensitivity of the light sensing elements is reduced, the light sensing elements lgtSU(X1,Y1)~lgtSU(X2,Y2) are less likely to generate leakage current due to overexposure to light. However, although this approach can improve the phenomenon of excessive light (overexposure) in the overexposed area 27a in the image 27, it makes the non-overexposed area 27c and other areas darker. Even the details of the overexposed area 27a will not be presented. Therefore, how to improve the overexposure phenomenon while maintaining the imaging effect of the image still needs to be improved.

The invention relates to a light sensing element and a sensing panel. The light sensing element includes an active sensing part and a passive reading part. The active sensing part is a sensing transistor, which is used to sense the light intensity of the light sensing element in advance before passive reading. After that, based on the sensing results, it is selected whether to change the main scanning signal line before performing passive reading. The voltage is used to compensate for the effect of the data reading signal line, preventing the light sensing element from generating leakage current due to overexposure, thereby improving the artifacts caused by leakage current.

According to a first aspect of the present invention, a light sensing element is provided. The light sensing element is electrically connected to the data reading signal line, the light intensity sensing signal line, the main scanning signal line and the auxiliary scanning signal line. The light sensing element includes: photosensitive circuit, sensing transistor and reading transistor. The photosensitive circuit is electrically connected to the sensing terminal and the auxiliary scanning signal line. The photosensitive circuit senses light intensity during illumination so that the voltage at the sensing terminal changes with the light intensity. The sensing transistor is electrically connected to the sensing terminal and the light intensity sensing signal line. The sensing transistor changes the voltage of the light intensity sensing signal line in response to the voltage of the sensing terminal during the light intensity sensing period. The voltage of the main scanning signal line is selectively changed in response to the voltage of the light intensity sensing signal line during the compensation period. The reading transistor is electrically connected to the sensing terminal, the data reading signal line and the main scanning signal line. The reading transistor is turned on according to the pulse wave of the main scanning signal line during reading, so that the data reading signal line reflects the voltage of the sensing endpoint. The light intensity sensing period is later than the illumination period, the compensation period is later than the light intensity sensing period, and the reading period is later than the compensation period.

According to a second aspect of the present invention, a sensing panel electrically connected to a controller is provided. The sensing panel includes: a plurality of light sensing elements arranged in M rows and N columns. The light sensing elements include the aforementioned light sensing elements. The controller generates image data corresponding to the light sensing element according to the voltage of the data reading signal line during reading.

In order to have a better understanding of the above and other aspects of the present invention, examples are given below and are described in detail with reference to the accompanying drawings:

10,3:Light sensing system

11,33:Light source

13,311: Sensing panel

14: Subject

15,315,43,515:Controller

17,37:Display panel

imgDAT: image data

lgtSU(1,1),lgtSU(M,1),lgtSU(1,N),lgtSU(M,N),lgtSU(m,n),lgtSU(m,1),lgtSU(m,2),lgtSU (m,3),lgtSU(m,4): light sensing element

23,25,27:Image

23a,25a: Blank block

25c: Interference block

27a: Overexposed area

27c: non-overexposed area

31:Light sensing device

319a: Main selection circuit

319c: Auxiliary selection circuit

313:Image reading circuit

317:Light intensity sensing circuit

38: Bias circuit

lgtctlS: light source control signal

rdDAT_d[1]~rdDAT_d[M],rdDAT_d[m]: digital read signal

mctlS,ectlS: column selection control signal

mSR[1],mSR[N],mSR[n],mSR[2],mSR[3],mSR[4]: main scanning signal

eSR[1],eSR[N],eSR[n],eSR[2],eSR[3],eSR[4]: auxiliary scanning signal

Vbs: bias signal (line)

expDET[1],expDET[M],expDET[m]: light intensity sensing signal

bsES: bias enable signal

expDET_d[1]~expDET_d[M],expDET_d[m]: digital sensing signal

T1(m,n): read transistor

Np(m,n),Np(m,1),Np(m,2),Np(m,3),Np(m,4): sensing endpoint

D(m,n): photodiode

T2(m,n),T2(m,1),T2(m,2),T2(m,3),T2(m,4): sensing transistor

C(m,n): capacitance

Nbs: bias endpoint

413:Reading circuit

413a, 513a: Integrator

413c, 45a, 513c: Analog to digital converter

rdDAT[m]: data reading signal

rdDAT_a[m]: Analog integral reading signal

T[m]: voltage divider transistor

Vss: ground voltage

45:Light intensity sensing circuit

eqR(m,1),eqR(m,2),eqR(m,3),eqR(m,4): equivalent resistance

eqR _T [m]: voltage divider equivalent resistance

_Tucyc : component sensing period

uT_m1: During component reset

uT_m2: component lighting period

uT_m3: During component light intensity sensing

uT_m4: component compensation period

uT_m5: During component reading

Tmp: Pulse width of main scanning pulse wave

Vmp: the voltage amplitude of the main scanning pulse wave

Tep: Pulse width of auxiliary scanning pulse wave

Vrs: reset voltage

Vep: voltage amplitude of auxiliary scanning pulse wave

△Vdrp: pull-down voltage amplitude

t1~t7: time point

Vexp(m,n): Sensing voltage of light sensing element lgtSU(m,n)

Vrd(m,n): read voltage of light sensing element lgtSU(m,n)

T _cyc [x]: sensing period of the xth sensing

T _cyc [x+1]: sensing period of the (x+1)th sensing

pT_m1: During panel reset

pT_m2: panel lighting period

pT_m3: Panel light intensity sensing period

pT_m4: Panel compensation period

pT_m5: During panel reading

△t1, △t2, △t3, △t4: digital sensing period

△t5, △t6, △t7, △t8: Digital reading period

53:Multiplexer

fsS[m]: function selection signal

Mn:NMOS transistor

Mp: PMOS transistor

513: Light intensity sensing and image reading circuit

selDAT[m]: data selection signal

selDAT_a[m]: analog data selection signal

selDAT_d[m]: digital data selection signal

Figure 1 is a schematic diagram of the light sensing system that performs When a certain area in the front is overexposed, under ideal conditions, the display panel restores the image based on the image data imgDAT; Figure 4A shows when a certain area in front of the sensing panel is overexposed and leakage occurs. When the current phenomenon occurs, the brightness of some areas in the image displayed based on the image data is disturbed by the conventional technology. Figure 4B shows that the conventional technology adopts the method of reducing the sensitivity of the light sensing element to improve the brightness of the image in Figure 4A. A schematic diagram of the image; Figure 5, which is a block diagram of the light sensing system according to the concept of the present disclosure; Figure 6, which is a schematic diagram of the internal components of the light sensing element lgtSU(m,n) based on the concept of the present disclosure; Figure 7, which is the relationship between the on-current Ids and the gate-source voltage difference Vgs of the reading transistor T1(m,n) in the light sensing element lgtSU(m,n); Figure 8, which Schematic diagram of the controller, coupled with an analog-to-digital converter and a reading circuit, sensing and reading the light sensing elements lgtSU(m,1)~lgtSU(m,4) also located in the mth row; 9A and 9B , Figure 9C, which is because the connection relationship of the sensing transistors T2(m,1)~T2(m,4) in the light sensing elements lgtSU(m,1)~lgtSU(m,4) is expressed as parallel connection with each other. The schematic diagram of the equivalent resistance eqR(m,1)~eqR(m,4); Figure 10, which is the light sensing element lgtSU(m,n) without overexposure and overexposure, and the light sensor The waveform diagram of the control signal related to the sensing element lgtSU(m,n); Figure 11, which is based on the structure of Figure 8, and the light sensing element lgtSU(m,1)~lgtSU(m,4) The waveform diagram of the corresponding control signal; and Figure 12, which is a schematic diagram of combining the sensing circuit and the reading circuit using a multiplexer.

In order to improve the problems of conventional technologies, the present disclosure provides a light sensing element and a sensing panel that can avoid leakage current caused by overexposure. By suppressing the occurrence of leakage current, the image data generated by the controller based on the sensing panel will not be distorted. Therefore, when the display panel displays image data, there will not be a situation where a certain area of the sensing panel is too bright when receiving light, thereby affecting the display effect of other areas.

Please refer to Figure 5, which is a block diagram of a light sensing system conceived according to the present disclosure. The light sensing system 3 includes: a light source 33 , a light sensing device 31 and a display panel 37 . Here is a brief introduction to the connection relationships of each component and the signals transmitted between them. The timing and usage of the signal will be explained in the following diagrams. Furthermore, in this document, the same symbol is used to represent a signal, as well as a signal line carrying the signal. For example, Vbs represents both the bias signal and the bias signal line.

The light sensing device 31 includes: a controller 315, an image reading circuit 313, a sensing panel 311, a light intensity sensing circuit 317, a bias circuit 38, a main selection circuit 319a and an auxiliary selection circuit 319c. In practical applications, the controller 315, the image reading circuit 313, the light intensity sensing circuit 317, the bias circuit 38, the main selection circuit 319a and the auxiliary selection circuit 319c can be integrated into one control circuit. For ease of explanation, it is assumed here that the display panel 37 includes M*N pixels, and the sensing panel 311 includes M*N light sensing elements lgtSU(1,1)˜lgtSU(M,N). In actual application, the number of pixels included in the display panel 37 may be equal to or different from the number of light sensing elements included in the sensing panel 311 .

The controller 315 is electrically connected to the light source 33, the image reading circuit 313, the light intensity sensing circuit 317, the bias circuit 38, the main selection circuit 319a and the auxiliary selection circuit 319c. display panel 37 is electrically connected to the image reading circuit 313, the light intensity sensing circuit 317, the bias circuit 38, the main selection circuit 319a and the auxiliary selection circuit 319c.

The controller 315 sends the light source control signal lgtctls to the light source 33 to control the light source 33 to emit light or stop emitting light. In addition, the controller 315 generates image information imgDAT to the display panel 37 for the display panel 37 to display the measured image. The controller 315 transmits the column selection control signals mctlS and ectlS to the main selection circuit 319a and the auxiliary selection circuit 319c; and transmits the bias enable signal bsES to the bias circuit 38.

The main selection circuit 319a generates main scanning signals msR[1]~msR[N] to the sensing panel 311 according to the column selection control signal mctlS. The auxiliary selection circuit 319c generates auxiliary scanning signals eSR[1]~eSR[N] to the sensing panel 311 according to the column selection control signal ectlS. The bias circuit 38 adjusts the bias signal Vbs transmitted to the sensing panel 31 according to the bias enable signal bsES. The sensing panel 311 generates data reading signals rdDAT[1]~rdDAT[ in response to changes in the main scanning signals msR[1]~msR[N], the auxiliary scanning signals eSR[1]~eSR[N], and the bias signal Vbs. M] to the image reading circuit 313; and, generate light intensity sensing signals expDET[1]~expDET[M] to the light intensity sensing circuit 317.

After the light intensity sensing circuit 317 converts the light intensity sensing signals expDET[1]~expDET[M] into digital sensing signals expDET_d[1]~expDET_d[M], it converts the digital sensing signals expDET_d[1]~expDET_d[ M] and then sent to the controller 315. Among them, the controller 315 dynamically decides whether to adjust the format of the column selection control signal mctlS according to the digital sensing signals expDET_d[1]~expDET_d[M], thereby causing the main selection circuit 319a to change the main scanning signals mSR[1]~mSR[N ] voltage.

The image reading circuit 313 converts the data reading signals rdDAT[1]~rdDAT[M] into digital reading signals rdDAT_d[1]~rdDAT_d[M], and then converts the digital reading signals rdDAT_d[1]~rdDAT_d[M] are sent to the controller 315. Afterwards, the controller 315 generates image information imgDAT according to the digital read signals rdDAT_d[1]~rdDAT_d[M].

M，且n

N。此外，位於光感測元件lgtSU(m,n)的內部元件，將以相同的座標(m,n)表示。 To simplify the description, the following takes the light sensing element lgtSU(m,n) located in the m-th row and n-th column as an example. Among them, m and n are positive integers, m

M, and n

N. In addition, the internal components located in the light sensing element lgtSU(m,n) will be represented by the same coordinates (m,n).

Please refer to Figure 6, which is a schematic diagram of the internal components of the light sensing element lgtSU(m,n) according to the concept of the present disclosure. The light sensing element lgtSU(m,n) includes: reading transistor T1(m,n), sensing transistor T2(m,n), photodiode D(m,n) and capacitor C(m, n). Among them, the photodiode D(m,n) and the capacitor C(m,n) are connected in parallel and can be regarded as a photosensitive circuit.

The gate of the read transistor T1(m,n) receives the main scanning signal mSR[n], the source is electrically connected to the sensing terminal Np(m,n), and the drain is electrically connected to the data read signal line rdDAT[ m]. The gate of the sensing transistor T2(m,n) is electrically connected to the sensing terminal Np(m,n), the drain receives the bias signal Vbs, and the source is electrically connected to the light intensity sensing signal line expDET[m] . The anode of the photodiode D(m,n) receives the auxiliary scanning signal eSR[n], and the cathode is electrically connected to the sensing terminal Np(m,n). One end of the capacitor C(m,n) receives the auxiliary scanning signal eSR[n], and the other end is electrically connected to the sensing terminal Np(m,n).

It can be seen from the connection relationship in Figure 6 that the conduction of the read transistor T1(m,n) depends on the voltage difference between the main scanning signal mSR[n] and the sensing endpoint Np(m,n) . Moreover, when the read transistor T1(m,n) is turned on, the voltage of the sensing terminal Np(m,n) is equal to the data read signal rdDAT[m]. In addition, whether the sensing transistor T2(m,n) is turned on depends on the voltage difference between the sensing terminal Np(m,n) and the light intensity sensing signal expDET[m]. Among them, the sensing terminal Np(m,n) is affected by the charge and discharge of the capacitor C(m,n) and the voltage change of the photodiode D(m,n).

Vth)時，讀取電晶體T1(m, n)處於導通狀態。當讀取電晶體T1(m,n)的閘極-源極壓差Vgs小於臨界電壓(Vgs<Vth)時，讀取電晶體T1(m,n)處於關閉狀態。 Please refer to Figure 7, which is a relationship diagram between the on-current Ids and the gate-source voltage difference Vgs of the read transistor T1(m,n) in the light sensing element lgtSU(m,n). When the gate-source voltage difference Vgs of the reading transistor T1(m,n) is greater than or equal to the critical voltage (Vgs

Vth), the read transistor T1(m, n) is in the conducting state. When the gate-source voltage difference Vgs of the read transistor T1(m,n) is less than the critical voltage (Vgs<Vth), the read transistor T1(m,n) is in a closed state.

When the read transistor T1(m,n) is in the off state, as the gate-source voltage difference Vgs changes, the read transistor T1(m,n) may leak current. As shown in Figure 7, if the gate-source voltage difference Vgs is lower than the voltage V1, or between the voltage V2 and 0V, the leakage current of the reading transistor T1(m,n) is high. On the other hand, if the gate-source voltage difference Vgs is between the voltage V1 and the voltage V2, the leakage current of the read transistor T1(m,n) is low.

Please also see Figures 6 and 7. As shown in Figure 6, the gate of the read transistor T1(m,n) receives the main scanning signal mSR[n], and the source is electrically connected to the sensing terminal Np(m,n). Therefore, the gate-source voltage difference Vgs of the read transistor T1(m,n) is the voltage difference between the main scanning signal mSR[n] and the sensing terminal Np(m,n).

Since the cathode of the photodiode D(m,n) is electrically connected to the sensing terminal Np(m,n), and the voltage difference between the two ends of the photodiode D(m,n) increases with the changes with light intensity. Relatedly, the gate-source voltage difference Vgs of the reading transistor T1(m,n) also changes with the illumination intensity of the light sensing element lgtSU(m,n). According to the foregoing description, as the light intensity of the light sensing element lgtSU(m,n) is different, the voltage of the sensing terminal Np(m,n) and the gate-source of the reading transistor T1(m,n) The extreme voltage difference Vgs, the state of the reading transistor T1(m,n) and the leakage current also change accordingly, as shown in Table 1.

When leakage current occurs in the read transistor T1(m,n), the data read signal rdDAT[m] will be affected. Since the data read signal line rdDAT[m] is connected to the read transistors T1(m,1)~T1(m,N) at the same time, the read transistors T1(m,1)~T1(m,N) They may interfere with each other. Depending on the actual application, the selection order of the main scanning signals mSR[1]~mSR[N] may be different. Moreover, as the selection order (pulse wave generation order) of the main scanning signals mSR[1]~mSR[N] is different, the interference phenomenon formed between the read transistors T1(m,1)~T1(m,N) Also changed.

When the selection order of the main scanning signals mSR[1]~mSR[N] is increasing (from 1 to N), if the reading transistor T1(m,n) leaks current, it will affect the reading transistor T1(m,n). Operations of m,1)~T1(m,n-1). In other words, when the selection order of the main scanning signals mSR[1]~mSR[N] is 1 to N, the leakage current phenomenon of the read transistor T1(m,n) also affects the pixels PXL(m,1)~PXL (m,n-1) brightness when displayed.

On the other hand, when the selection order of the main scanning signals mSR[1]~mSR[N] is decreasing (from N to 1), if the reading transistor T1(m,n) leaks current, it will affect the reading. Operation of transistors T1(m,n+1)~T1(m,N). In other words, when the selection order of the main scanning signals mSR[1]~mSR[N] is from N to 1, the leakage current phenomenon of the read transistor T1(m,n) also affects the pixel PXL(m,n+1) ~PXL(m,N) brightness when displayed.

In other words, the selection order of the main scanning signals mSR[1]~mSR[N] will affect the position on the display panel 37 where interference is present. For ease of explanation, the embodiment of this article assumes that the selection order of the main scanning signals mSR[1]~mSR[N] is increasing (from 1 to N). However, in practical applications, a similar approach can also be applied to the case where the selection order of the main scanning signals mSR[1]~mSR[N] is decreasing (from N to 1).

Please also see Figures 4A, 6, and 7. For the light sensing elements lgtSU(m,1)~lgtSU(m,Y1), the relationship between the on-current Ids and the gate-source voltage difference Vgs is located at point A in Figure 7. That is, the light sensing elements lgtSU(m,1)~lgtSU(m,Y1) are in a low leakage state in the off state. However, for the light sensing elements lgtSU(m,Y1+1)~lgtSU(m,Y2), the relationship between the on-current Ids and the gate-source voltage difference Vgs is located at point B in Figure 7. That is, the light sensing elements lgtSU(m,1)~lgtSU(m,Y1) are in a high leakage state in the off state.

As shown in Figure 4A, if the light sensing elements lgtSU(m,Y1)~lgtSU(m,Y2)( When m=X1~X2) is overexposed, the light sensing elements lgtSU(m,Y1)~lgtSU(m,Y2) will generate leakage current and affect the voltage of the data reading signal line rdDAT[m]. Accordingly, when the main scanning signal mSR[n] selects the light sensing elements lgtSU(m,Y1)~lgtSU(m,Y2) corresponding to the pixels located in the Y1~Y2 columns, the light sensing element lgtSU(m, Y1)~lgtSU(m,Y2) generates leakage current flowing to the data read signal line rdDAT[m], which in turn affects the characteristics of the read transistors T1(m,1)~T1(m,Y1) and the controller 315 is the result when reading from the reading transistors T1(m,1)~T1(m,Y1).

Referring to Figure 7, it can be known that the leakage current of the read transistor T1(m,n) is related to the gate-source voltage difference Vgs of the read transistor T1(m,n). Therefore, the present disclosure provides a method for controlling the read transistor T1(m,n) by sensing the voltage of the terminal Np(m,n) in advance and adjusting the voltage of the main scanning signal mSR[n] according to the sensing result. ), the gate-source voltage difference Vgs puts the read transistor T1(m,n) in a low leakage current state. This approach is equivalent to changing the gate-source voltage difference Vgs of the read transistors T1(m,Y1)~T1(m,Y2), so that the relationship between the conduction current Ids and the gate-source voltage difference Vgs Move from point B to point C in Figure 7. Once the states of the reading transistors T1(m,Y1)~T1(m,Y2) are controlled at point C in Figure 7, the drains of the reading transistors T1(m,Y1)~T1(m,Y2) The current will not affect the reading result of the controller 315 using the data reading signal rdDAT[m] to read the sensing endpoints Np(m,1)~Np(m,(Y1-1)) of the previous stage.

In order to more specifically explain the control method of the light sensing elements located in the same row due to different light intensities, the following is a description of the light sensing element lgtSU(m, 1)~lgtSU(m,4) circuit connection relationship (Figure 8), and its corresponding waveform diagram (Figure 11).

Please refer to Figure 8. The controller is equipped with an analog-to-digital converter and a reading circuit to sense and read the light sensing elements lgtSU(m,1)~lgtSU(m,4) also located in the mth row. schematic diagram. Since the internal components of the light sensing elements lgtSU(m,1)~lgtSU(m,4) are similar to those in Figure 6, they will not be described in detail here.

The light sensing elements lgtSU(m,1)~lgtSU(m,4), also located in the mth row, are electrically connected to the data reading signal line rdDAT[m], the light intensity sensing signal line expDET[m] and the bias voltage. Signal line Vbs. The light sensing element lgtSU(m,n) is connected to the main scanning signal mSR[n] and the auxiliary scanning signal eSR[n] in the order of each column. The light sensing element lgtSU(m,1) receives the main scanning signal mSR[1] and the auxiliary scanning signal eSR[1]; the light sensing element lgtSU(m,2) receives the main scanning signal mSR[2] and the auxiliary scanning signal eSR [2]; The light sensing element lgtSU(m,3) receives the main scanning signal mSR[3] and the auxiliary scanning signal eSR[3]; and, the light sensing element lgtSU(m,4) receives the main scanning signal mSR[4] ] and auxiliary scanning signal eSR[4].

The light sensing elements lgtSU(m,1)~lgtSU(m,4) take turns to determine the voltage of the light intensity sensing signal expDET[m], and transmit the light intensity sensing signal expDET[m] to the light intensity sensing circuit 45 . The light intensity sensing circuit 45 includes a voltage dividing transistor T[m] and an analog-to-digital converter 45a. One end of the voltage dividing transistor T[m] is electrically connected to the light intensity sensing signal line expDET[m], and the other end is electrically connected to the ground voltage Vss. The gate of the voltage-dividing transistor T[m] receives a constant voltage Vd, so that the voltage-dividing transistor T[m] maintains a semi-conductive state. The analog-to-digital converter 45a is electrically connected to the light intensity sensing signal line expDET[m] and the controller 43. The analog-to-digital converter 45a converts the light intensity sensing signal expDET[m] After being converted into a digital sensing signal expDET_d[m], the digital sensing signal expDET_d[m] is sent to the controller 43 .

Through the time-sharing switching control method, the light sensing elements lgtSU(m,1)~lgtSU(m,4) take turns to determine the voltage of the data reading signal rdDAT[m] and transmit the data reading signal rdDAT[m] to read circuit 413. The reading circuit 413 includes an integrator 413a and an analog-to-digital converter 413c. After the integrator 413a converts the data read signal rdDAT[m] into the analog integral read signal rdDAT_a[m], it transmits the analog integral read signal rdDAT_a[m] to the analog-to-digital converter 413c. The analog-to-digital converter 413c further converts the analog integral read signal rdDAT_a[m] into a digital read signal rdDAT_d[m], and transmits the digital read signal rdDAT_d[m] to the controller 43 . Afterwards, the controller 43 converts the digital read signal rdDAT_d[m] into image information imgDAT provided to the display panel 37 .

Please refer to Figures 9A, 9B, and 9C, which are due to the sensing transistors T2(m,1)~T2(m,4) in the light sensing elements lgtSU(m,1)~lgtSU(m,4). The connection relationship is expressed as a schematic diagram of equivalent resistances eqR(m,1)~eqR(m,4) connected in parallel with each other. Please also see Figures 8 and 9A.

The 9A diagram illustrates elements related to the light intensity sensing signal expDET[m] among the light sensing elements lgtSU(m,1)~lgtSU(m,4). It can be seen from Figure 8 that one end of the sensing transistors T2(m,1)~T2(m,4) is electrically connected to the bias terminal Nbs, and the sensing transistors T2(m,1)~ The other ends of T2(m, 4) are both electrically connected to the light intensity sensing signal line expDET[m]. Therefore, in Figure 9A, the sensing transistors T2(m,1)~T2(m,4) can be regarded as being connected in parallel with each other. In addition, the voltage dividing transistor T[m] is also electrically connected to the light intensity sensing signal line expDET[m].

When the auxiliary scanning signal eSR[n] is a high voltage, the sensing transistors T2(m,1)~T2(m,4) are in a semi-conducting state. Therefore, in Figure 9B, the sensing transistors T2(m,1)~T2(m,4) are expressed as individual equivalent resistances eqR(m,1)~eqR(m,4), and the divided voltage The transistor T[m] is expressed as the voltage-divided equivalent resistance eqR _T [m]. Continuing from Figure 9A, it can be seen that the individual equivalent resistances eqR(m,1)~eqR(m,4) of the sensing transistors T2(m, 1)~T2(m,4) are connected in parallel with each other. Moreover, the parallel equivalent resistance eqR[m] can be expressed as, eqR[m]=eqR(m,1)//eqR(m,2)//eqR(m,3)//eqR(m,4). According to the resistance formula, it can be known that the resistance value of the parallel equivalent resistance eqR[m] also changes as the resistance value of the individual equivalent resistances eqR(m,1)~eqR(m,4) changes. When the resistance value of the individual equivalent resistors eqR(m,1)~eqR(m,4) is larger, the resistance value of the parallel equivalent resistance eqR[m] corresponding to the m-th row is larger; conversely, when the individual equivalent resistances eqR(m,1)~eqR(m,4) are The smaller the resistance value of the effective resistance eqR(m,1)~eqR(m,4), the smaller the resistance value of the parallel equivalent resistance eqR[m] corresponding to the m-th row.

In Figure 9C, the parallel equivalent resistance eqR[m] and the voltage-divided equivalent resistance eqR _T [m] in series with each other are represented in the light sensing elements lgtSU(m,1)~lgtSU(m,4), and The equivalent circuit formed by the components related to the light intensity sensing signal expDET[m]. As can be seen from Figure 9C, the light intensity sensing signal line expDET[m] can be obtained based on the parallel equivalent resistance eqR[m] and the voltage-divided equivalent resistance eqR _T [m]. That is, expDET[m]=(Vbs-Vss)*eqR _T [m]/(eqR _T [m]+eqR[m]). When the resistance value of the parallel equivalent resistance eqR[m] corresponding to the m-th row is smaller, the voltage of the light intensity sensing signal expDET[m] is higher. Or, when the resistance value of the parallel equivalent resistance eqR[m] corresponding to the m-th row is larger, the voltage of the light intensity sensing signal expDET[m] is smaller.

According to the characteristics of the crystal, if the voltage difference between the gate voltage of the sensing transistor T2(m,n) and the bias signal Vbs is larger, the conduction current Ids flowing through the sensing transistor T2(m,n) will also be larger. big. Therefore, when the sensing transistor T2(m,n) is turned on, the size of its corresponding individual equivalent resistance eqR(m,n) changes with the size of the conduction current. That is, when the on-current Ids flowing through the sensing transistor T2(m,n) is larger, the individual equivalent resistance eqR(m,n) is smaller. Table 2 summarizes how the signals and parameters related to the light sensing element lgtSU(m,n)(n=1~4) change with different exposure levels.

As mentioned before, when the voltage of the sensing terminal Np(m,n) is higher, it means that the light intensity corresponding to the light sensing element lgtSU(m,n) is weaker (the degree of light shading of the object being measured is higher). Moreover, the voltage of the light intensity sensing signal expDET[m] is higher.

On the other hand, when the voltage of the sensing terminal Np(m,n) is lower, it means that the illumination intensity corresponding to the light sensing element lgtSU(m,n) is stronger (the degree of shading of the object under test is lower). Moreover, the voltage of the light intensity sensing signal expDET[m] is lower.

Therefore, the controller 43 can learn whether the light intensity received by the light sensing element lgtSU(m,n) may cause overexposure according to the voltage change of the light intensity sensing signal expDET[m]. That is, when the digital sensing signal expDET_d[m] received by the controller 43 represents the higher voltage of the light intensity sensing signal expDET[m], it represents the higher voltage of the sensing end point Np(m,n), and The weaker the light intensity of the light sensing element lgtSU(m,n).

Furthermore, the controller 43 can set a preset threshold as a basis for determining whether the light sensing element lgtSU(m,n) is overexposed. When the voltage of the light intensity sensing signal expDET[m] is higher than or equal to the preset threshold, the controller 43 can determine that the voltage of the sensing terminal Np(m,n) is not biased by the digital sensing signal expDET_d[m]. Low, that is, the light sensing element lgtSU(m,n) is not overexposed. On the contrary, when the voltage of the light intensity sensing signal expDET[m] is lower than the preset threshold, the controller 43 can use digital sensing to The signal expDET_d[m] determines that the voltage of the sensing terminal Np(m,n) is low, that is, the light sensing element lgtSU(m,n) has been overexposed.

Thereafter, during the element compensation period uT_m4, the controller 43 can dynamically determine whether to change the voltage of the main scanning signal mSR[n] based on the voltage of the light intensity sensing signal expDET[n] during the element light intensity sensing period uT_m3. . If the voltage of the light intensity sensing signal expDET[n] is low, the voltage of the main scanning signal mSR[n] needs to be pulled down (-8V→-9V) during the element compensation period uT_m4. Since the main scanning signal line mSR[n] is electrically connected to the gate of the reading transistor T1(m,n), pulling down the voltage of the main scanning signal mSR[n] will affect the reading transistor T1(m,n). The gate-source voltage difference Vgs of n) changes the leakage current of the read transistor T1(m,n) (moving from point B to point C in Figure 7). On the contrary, if the light intensity sensing signal expDET[n] is not low, the voltage of the main scanning signal mSR[n] is maintained during the element compensation period pT_m4.

According to the connection method of the sensing transistors T2(m,1)~T2(m,4) and the voltage dividing transistor T[m] adopted in the present disclosure, the flow through the sensing transistor T2(m,1) can be The currents of ~T2(m,4) and the voltage dividing transistor T[m] reflect the voltage of the sensing terminals Np(m,1)~Np(m,4), which is an active sensing method. On the other hand, the read transistor T1(m,n) adopts a passive read operation. Next, use Figure 10 to compare how the control signal related to the light sensing element lgtSU(m,n) changes with different light intensities.

The dotted line frame at the top of Figure 10 is the waveform diagram of the control signal related to the light sensing element lgtSU(m,n) when the light sensing element lgtSU(m,n) is not overexposed; Figure 10 The dotted line frame below is the waveform diagram of the control signal related to the light sensing element lgtSU(m,n) when the light sensing element lgtSU(m,n) is overexposed.

The horizontal axis of Figure 10 is time. The element sensing period Tucyc of the light sensing element lgtSU(m,n) includes: element reset period uT_m1, element illumination period uT_m2, element light intensity sensing period uT_m3, element compensation period uT_m4, and element reading period uT_m5.

The vertical axis of Figure 10 is the main scanning signal mSR[n] received by the light sensing element lgtSU(m,n), the auxiliary scanning signal eSR[n], the voltage of the sensing end point Np(m,n), Light intensity sensing signal expDAT[m], data reading signal rdDAT[m]. In addition, in order to compare the difference between uncompensated and compensated, the waveform of the main scanning signal mSR[n] is divided into two types in the dotted line selection at the bottom of Figure 10. One is the waveform without compensation (equivalent to reading Take the transistor T1(m,n) to be at point B in Figure 7); the other is the waveform when performing compensation (equivalent to making the reading transistor T1(m,n) be at point C in Figure 7).

In this diagram, the dotted bottom of the net indicates the signal in the floating state. For example, the light intensity sensing signal expDET[m] is in a floating state during periods other than the component light intensity sensing period uT_m3; and, during the component reset period uT_m1 and the component reading period uT_m5, the data read signal rdDAT[ m] are all in floating state. Next, in chronological order, the change pattern of the signal related to the light sensing element lgtSU(m,n) is explained when the light sensing element lgtSU(m,n) is not overexposed and overexposed.

During the element reset period uT_m1 (during time points t1 to t2), the main scanning signal mSR[n] generates a main scanning pulse wave (for example, 8.5V) that turns on the read transistor T1(m,n). The pulse width of the main scanning pulse wave is Tmp, and the voltage amplitude of the main scanning pulse wave is Vmp. As the read transistor T1(m,n) is turned on, the capacitor C(m,n) receives the data read signal rdDAT[m] and is charged. When the capacitor C(m,n) is full, the voltage of the sensing terminal Np(m,n) (Np(m,n)=Vrst) is set to the reset voltage (Vrst). At the same time, the auxiliary scanning signal eSR[n] is still at a low voltage (for example, -7V). During the element reset period uT_m1, the gradually increasing voltage of the sensing terminal Np(m,n) is not enough to turn on the sensing transistor T2(m,n). Therefore, the light intensity sensing signal expDET[m] is in a floating state during the element reset period because the sensing transistor T2(m,n) is turned off. The data read signal rdDAT[m] receives the current output from the controller 43 during the element reset period, and passes through the turned on read transistor T1(m, n) Conduct current to the sensing terminal Np(m,n). Therefore, the voltage of the data read signal rdDAT[m] during the component reset period uT_m1 is equal to the voltage of the sensing terminal Np(m,n).

Please also note that the voltage of the sensing terminal Np(m,n) (Np(m,n)=Vrst) may be different from the voltage at the beginning of the component reset period uT_m1 (time point t1). For example, if the light sensing system 3 performs X-ray diagnostic shooting for the first time after being powered on, the voltage of the sensing terminal Np(m,n) (Np(m,n)=Vrst) at time point t1 is 0V. . If X-ray diagnostic shooting is performed continuously, the voltage of the sensing end point Np(m,n) (Np(m,n)=Vrst) at time point t1 is the sensing result after the previous X-ray diagnostic shooting.

During the component illumination period uT_m2 (t2~t3), the controller 43 controls the X-ray light source to emit light. When the intensity of X-ray is stronger, the component illumination period uT_m2 (t2~t3) is shorter. During the element illumination period uT_m2 (t2~t3), the voltage difference between the two ends of the photodiode D(m,n) changes with the different exposure intensity received by the light sensing element lgtSU(m,n). Once the voltage difference across the photodiode D(m,n) changes, the voltage of the sensing terminal Np(m,n) also changes accordingly.

As the tissue distribution of the subject is different, the light intensity received by the light sensing element lgtSU(m,n) at different positions is also different. Relatedly, the voltage drop amplitude of the sensing terminal Np(m,n) varies with the position of the light sensing element lgtSU(m,n). It can be seen from Figure 10 that at the end of the component lighting period uT_m2 (time point t3), if the light intensity received by the light sensing component lgtSU(m,n) is low (as marked by the dotted line selection above), the sensor The voltage of the sensing endpoint Np(m,n) is higher; if the light intensity received by the light sensing element lgtSU(m,n) is higher (as indicated by the dotted line selection below), the sensing endpoint Np(m,n) n) has a lower voltage.

During the element illumination period uT_m2 (during time point t2~t3), the main scanning signal mSR[n] and the auxiliary scanning signal eSR[n] are both low voltage (mSR[n]=-8V, eSR[n]=-7V). Therefore, during the device illumination period uT_m2 is equal to the sensing transistor T2(m,n) and the reading transistor T1(m,n). for disconnection. Together, the light intensity sensing signal expDET[m] and the data reading signal rdDAT[m] are both in a floating state during the component illumination period uT_m2 (t2~t3).

During the element light intensity sensing period uT_m3 (during time points t3 to t4), the controller 43 controls the light source to stop emitting light. At the same time, the auxiliary scan signal eSR[n] generates the auxiliary scan pulse wave (for example, 4V) and makes the voltage of the sensing endpoint Np(m,n) combine with the coupling effect of the capacitor C(m,n). Increase the amplitude of Vrs. For ease of explanation, the pulse width of the auxiliary scanning pulse wave is defined as Tep, and the voltage amplitude of the auxiliary scanning pulse wave is defined as Vep. As shown in Figure 6, one end of the capacitor C(m,n) receives the auxiliary scanning signal eSR[n]. Therefore, when the voltage of the auxiliary scan signal eSR[n] rises with the auxiliary scan pulse wave, the voltage rise amplitude Vrs of the sensing end point Np(m,n) is equal to the voltage amplitude Vep of the auxiliary scan pulse wave (Vrs= Vep). Therefore, during the element light intensity sensing period uT_m3, the sensing transistor T2(m,n) is turned on as the gate receives the increased voltage of the sensing terminal Np(m,n). Continuing the description in Figures 9A, 9B, and 9C and Table 2, it can be known that the on-current Ids of the sensing transistor T2(m,n) changes with the voltage of the sensing terminal Np(m,n), and the light The intensity sensing signal expDET[m] is also affected.

Please note that the voltage of the sensing terminal Np(m,n) at time point t4 (ie, the sensing voltage Vexp(m,n) of the light sensing element lgtSU(m,n)) is equivalent to the sensing terminal Np The voltage of (m, n) is the sum of the voltage at time point t3 and the voltage amplitude Vep of the auxiliary scanning pulse wave. Since the voltage amplitude Vep of the auxiliary scanning pulse wave is fixed, and at the end of the component illumination period uT_m2 (time point t3), the voltage of the sensing endpoint Np(m,n) when the illumination intensity is low is higher than the sensing The voltage of endpoint Np(m,n) when the light intensity is high. Relatedly, at the end of the component light intensity sensing period uT_m3 (time point t4), the voltage of the sensing endpoint Np(m,n) when the light intensity is low (selected by the dotted line above) is also higher than the light intensity. The voltage of the sensing endpoint Np(m,n) when it is higher (selected by the dotted line box below).

Since the main scanning signal mSR[n] is low voltage uT_m3 during the component light intensity sensing period (for example, mSR[n]=-8V), the read transistor T1(m,n) is turned off during this period. Under ideal conditions, no current flows through the read transistor T1(m,n). However, as can be seen from Figure 7, where The read transistor T1(m,n) in the off state may still have leakage current due to the difference in gate-source voltage difference Vgs.

Please also see the waveform selected by the dashed line above Figure 10 and the first column of Table 2. When the light intensity received by the light sensing element lgtSU(m,n) is weak, the voltage of the sensing terminal Np(m,n) is higher at time point t4. Relatedly, the voltage of the light intensity sensing signal expDET[m] is also higher at time point t4. Therefore, the controller 43 can learn the light sensing element lgtSU(m, n) in dark state.

According to the foregoing description, it can be known that in this case, the read voltage Vrd(m,n) represented by the data read signal rdDAT[m] and corresponding to the light sensing element lgtSU(m,n) is relatively high. Furthermore, since the voltage of the sensing terminal Np(m,n) connected to the source of the reading transistor T1(m,n) is higher at time point t4, the reading transistor T1(m,n) The gate-source voltage difference Vgs is small. Therefore, the read transistor T1(m,n) is in the state of point A in FIG. 7, and the leakage current flowing through the read transistor T1(m,n) is low.

Please also see the waveform selected by the dotted line below Figure 10 and the second column of Table 2. When the light intensity received by the light sensing element lgtSU(m,n) is relatively strong, the voltage of the sensing terminal Np(m,n) at time point t4 is relatively low. Relatedly, the voltage of the light intensity sensing signal expDET[m] at time point t4 is also low. Therefore, the controller 43 can learn the light sensing element lgtSU(m, n) is in a bright state.

According to the foregoing description, it can be known that in this case, the read voltage Vrd(m,n) represented by the data read signal rdDAT[m] and corresponding to the light sensing element lgtSU(m,n) is relatively low. Furthermore, because the voltage of the sensing terminal Np(m,n) connected to the gate source of the reading transistor T1(m,n) is low at time t4, the reading transistor T1(m,n) The gate-source voltage difference Vgs is larger. because Therefore, the reading transistor T1 (m, n) is in the state of point B in FIG. 7, and the leakage current flowing through the reading transistor T1 (m, n) is high.

Since the leakage current of the read transistor T1(m,n) is small when the light sensing element lgtSU(m,n) is in the dark state, the controller 43 does not need to target the read transistor T1(m, n) make adjustments. Therefore, the controller 43 can maintain the main scanning signal mSR[n] at a low voltage (eg, mSR[n]=-8V) during the component compensation period uT_m4.

On the other hand, since the leakage current of the reading transistor T1(m,n) is large when the light sensing element lgtSU(m,n) is in the bright state, the controller 43 must adjust the reading transistor T1(m,n) during the element compensation period uT_m4. T1(m,n) is adjusted. That is, by changing the voltage of the main scan signal mSR[n], the gate-source voltage difference Vgs of the read transistor T1(m,n) is affected, so as to compensate the leakage of the read transistor T1(m,n). Effects of current phenomena. In the dotted frame selection at the bottom of Figure 10, the waveforms of the main scanning signal mSR[n] without compensation and the main scanning signal mSR[n] with compensation are listed simultaneously.

If the controller 43 does not use the main scanning signal mSR[n] for compensation, the main scanning signal mSR[n] is maintained at a low voltage (for example, mSR[n]=-8V) during the component compensation period uT_m4. If the controller 43 uses the main scanning signal mSR[n] for compensation, the main scanning signal mSR[n] will decrease from the low voltage (for example, -8V) by a pull-down voltage amplitude ΔVdrp (for example, -8V) during the component compensation period uT_m4 1V) to the compensation voltage (for example, -9V).

During the element compensation period uT_m4, the voltage of the sensing terminal Np(m,n) remains unchanged because the read transistor T1(m,n) is in the off state. Please also note that regardless of whether the main scan signal mSR[n] is used for compensation, the read transistor T1(m,n) and the sensing transistor T2(m,n) remain in the off state during the component compensation period uT_m4, so , the compensation method adopted in this disclosure does not affect the waveforms of the light intensity sensing signal expDET[m] and the data read signal rdDAT[m]. in practical application , as long as the main scanning signal mSR[n] can be pulled down to the compensation voltage before the panel compensation period pT_m4 ends.

During the element reading period uT_m5 (during time point t6~t7), the main scanning signal mSR[n] generates a pulse wave and turns on the reading transistor T1(m,n). As the read transistor T1(m,n) is turned on, the controller 43 charges the capacitor C(m,n) through the data read signal line rdDAT[m]. Furthermore, the controller 43 can know the sensing end point Np ( m, n) state.

According to the foregoing description, it can be known that the waveforms of the scanning signal mSR[n] during the element reset period uT_m1 and the reading period uT_m5 are the same. Moreover, while the controller 43 charges the capacitor C(m,n) through the data read signal line rdDAT[m], it can also gradually increase the voltage of the sensing terminal Np(m,n) to the reset level. Voltage Vrst. Therefore, in practical applications, this characteristic can be used to overlap the two sensing processes before and after, thereby improving the sensing efficiency.

Incidentally, in Figure 10, the pulse width Tmp of the main scanning pulse wave and the pulse width Tep of the auxiliary scanning pulse wave may be equal or different in length, and the pulse width Tmp of the main scanning pulse wave may be longer than that of the auxiliary scanning pulse wave. The pulse width Tep of the scanning pulse wave is wide or narrow. The voltage amplitude Vmp (-8V~8.5V) of the main scanning pulse wave is greater than the voltage amplitude Vep (-7V~4V) of the auxiliary scanning pulse wave.

According to the foregoing description, in Figure 10, the comparison of control signals related to the light sensing element lgtSU(m,n) with different light intensities can be summarized in Table 3 _.

Figure 10 illustrates the control signal, focusing more on the behavior of a single light sensing element lgtSU(m,n). Next, based on the scenario in Figure 3, the reason why the display panel 37 does not form the picture as shown in Figure 4A is explained when the sensing panel adopts the light sensing element lgtSU(m,n) of this case.

Please also see Figures 3, 8, and 11. It is assumed here that the light sensing elements lgtSU(m,1)~lgtSU(m,4) correspond to the pixels located in rows X1~X2 in Figure 3. And, assuming that the light sensing element The element lgtSU(m,1) corresponds to the pixel located above the blank area 23a in the image 23. It is assumed that the light sensing elements lgtSU(m,2) and lgtSU(m,3) correspond to the pixels located above the blank area 23a in the image. , and assume that the light sensing element lgtSU(m,4) corresponds to the pixel located below the blank area 23a in the image.

Please refer to Figure 11, which is a waveform diagram of the control signal corresponding to the light sensing elements lgtSU(m,1)~lgtSU(m,4) when the structure of Figure 8 is used. From top to bottom, this diagram shows the main scanning signals mSR[1]~mSR[4], the auxiliary scanning signals eSR[1]~eSR[4], the bias signal Vbs, the digital sensing signal expDET_d[m], and Digital read signal rdDAT_d[m]. Please note that the voltage values used in the description here are only used as examples to illustrate signal relationships and are not used to limit the application of this case.

The horizontal axis of Figure 11 is time. The period from time point t1 to t2 is the panel reset period pT_m1; the period from time point t2 to t3 is the panel illumination period pT_m2; the period from time point t3 to t4 is the panel light intensity sensing period pT_m3; the period from time point t4 to t6 is the panel compensation period pT_m4; and, The period from time point t6 to t7 is the panel reading period pT_m5. The following is explained in order of time. Please also see Figures 8 and 11.

During the panel reset period pT_m1, the main scanning signals mSR[1]~mSR[4] continuously generate main scanning pulse waves that rise from -8V to 8.5V and then drop to -8V. Among them, the periods Tmp of each main scanning pulse wave are equal to each other. The main scanning signals mSR[1]~ generated by the read transistors T1(m,1)~T1(m,4) in the light sensing elements lgtSU(m,1)~lgtSU(m,4) follow the cycle. The pulse wave of mSR[4] is turned on in turn, so that the capacitors C(m,1)~C(m,n) are charged in turns, thereby increasing the voltage of the sensing endpoints Np(m,1)~Np(m,4). rises to the reset voltage Vrst. At the same time, the auxiliary scanning signals eSR[1]~eSR[4] are -7V, and the bias signal Vbs is 0V. The light intensity sensing circuit 317 does not generate the digital sensing signal expDET_d[m], and the image capturing circuit 313 does not generate the digital reading signal rdDAT_d[m].

During the panel illumination period pT_m2, the controller 43 activates the light source 33. During this period, the signals generated by the light sensing elements lgtSU(m,1)~lgtSU(m,4) on the sensing panel 311 change with the measured Changes depending on the image. When the X-ray intensity emitted by the light source 33 is stronger, the panel illumination period pT_m2 is shorter, and vice versa. The photodiodes in the light sensing elements lgtSU(m,1)~lgtSU(m,4) sense different light intensities with different positions. During this period, the main scanning signals mSR[1]~mSR[4] are maintained at -8V, the auxiliary scanning signals eSR[1]~eSR[4] are maintained at -7V, the bias signal Vbs is maintained at 0V, and the digital sensor Neither the detection signal expDET_d[m] nor the digital read signal rdDAT_d[m] is generated.

During the panel light intensity sensing period pT_m3, the main scanning signals mSR[1]~mSR[4] are maintained at -8V, and the auxiliary scanning signals eSR[1]~eSR[4] are continuously generated after rising from -7V to 4V. , and then drops to the auxiliary scanning pulse wave of -7V. The periods Tep of each auxiliary scanning pulse wave are equal to each other. During the panel light intensity sensing period pT_m3, the bias signal Vbs rises to a positive voltage (for example, 4V or 5V), and the digital sensing signal expDET_d[m] generated according to the light intensity sensing signal expDET[m], The digital sensing periods △t1~△t4 correspond to the light sensing elements lgtSU(m,1)~lgtSU(m,4) respectively. During this period, the digital read signal rdDAT_d[m] has not yet been generated. The controller 43 first determines the light receiving conditions of the light sensing elements lgtSU(m,1)~lgtSU(m,4) based on the digital sensing signals expDET_d[m] during the digital sensing period Δt1~Δt4. The lengths of the digital sensing periods △t1~△t4 are shorter than the period Tep of the auxiliary scanning pulse wave, and the digital sensing periods △t1~△t4 are respectively between the periods corresponding to the auxiliary scanning signals eSR[1]~eSR[4]. Within the period Tep of the auxiliary scanning pulse wave.

Then, the controller 43 determines the main scanning signals mSR[1]~mSR[4 according to the light receiving conditions of the light sensing elements lgtSU(m,1)~lgtSU(m,4) determined during the panel light intensity sensing period pT_m3 ]The voltage of pT_m4 during panel compensation. Continuing the above assumption, that is, assuming that the light sensing elements lgtSU(m,1) and lgtSU(m,4) are not overexposed, the main scanning signals mSR[1] and mSR[4] are during the panel compensation period pT_m4 Maintain -8V. On the other hand, because the light sensing elements lgtSU(m,2) and lgtSU(m,3) are overexposed, the main scanning signals mSR[2] and mSR[3] are in the early stage of the panel compensation period pT_m4 (time point t4 ~t5 period) maintains -8V, but decreases to -9V in the later part of the panel compensation period pT_m4 (time point t5~t6 period). During panel compensation pT_m4, auxiliary scanning signal eSR[1]~eSR[4] are -7V, and the bias signal Vbs is 0V. Neither the digital intensity sensing signal expDET_d[m] nor the digital read signal rdDAT_d[m] is generated.

By the way, based on the consideration of simplified control, in practical applications, pT_m4 can be controlled synchronously to generate the main scanning signals mSR[1]~mSR[N] during the panel compensation period. That is, instead of just changing the waveform of the main scanning signal mSR[n] corresponding to the light sensing element lgtSU(m,n) in the column where the overexposure phenomenon occurs, it is found that the N light sensors located in the mth row When any column of the measuring components lgtSU(m,1)~lgtSU(m,N) is overexposed, pT_m4 will synchronously generate main scanning signals mSR[1]~mSR[N] with compensation waveforms during the panel compensation period.

This method of synchronously changing the voltage of the main scanning signals mSR[1]~mSR[N] does not need to control the specific number of columns where overexposure occurs, but controls all the number of columns as a whole, so it can Simplify control complexity. As mentioned before, pT_m4 changes the voltage of the main scanning signals mSR[1]~mSR[N] during the panel compensation period and does not affect the waveforms of other signals. Therefore, this approach will not affect the data reading signal rdDAT[m] received by the light intensity sensing circuit 45, nor will it affect the digital intensity sensing signal expDET_d[m] received by the controller 43.

During the panel reading period pT_m5, the main scanning signals mSR[1]~mSR[4] continuously generate main scanning signal pulses that first rise from -8V or -9V to 8.5V, and then drop to -8V or -9V. The auxiliary scanning signals eSR[1]~eSR[4] are maintained at -7V during panel reading, and the bias signal Vbs is 0V. The light intensity sensing signal expDET[m] is not generated during panel reading. The digital read signal rdDAT_d[m] generated according to the data read signal rdDAT[m] is connected to the light sensing element lgtSU(m,1)~lgtSU(m,4) respectively during the digital read period △t5~△t8. correspond. Therefore, the controller 43 can generate images corresponding to the light sensing elements lgtSU(m,1)~lgtSU(m,4) respectively according to the digital read signals rdDAT_d[m] during the digital read period Δt5~Δt8. material. The lengths of the digital reading periods △t5~△t8 are shorter than the period Tmp of the main scanning pulse wave, and the digital reading periods △t5~△t8 are respectively between those corresponding to the main scanning signals mSR[1]~mSR[4]. It mainly scans the period Tmp of the pulse wave.

When controlling the sensing panel 311 in the manner shown in Figure 11, the controller 43 can determine the light sensing element lgtSU(m,1) based on the change of the digital sensing signal expDET_d[m] during the digital sensing period Δt1~Δt4. Whether the light intensity sensed by ~lgtSU(m,4) is too strong. In addition, compensation is performed for the light sensing elements lgtSU(m,2) and lgtSU(m,3) that are overexposed, thereby dynamically changing the main scanning signals mSR[2] and mSR[3] during the panel compensation period pT_m4 voltage.

As the main scanning signals mSR[2], mSR[3] change pT_m4 during the panel compensation period, the leakage current situation in the light sensing elements lgtSU(m,2), lgtSU(m,3) will be improved. Therefore, the brightness of the light sensing element lgtSU(m,1) will not change due to the leakage current of the light sensing elements lgtSU(m,2) and lgtSU(m,3). Therefore, when using the light sensing element conceived in this project, the display panel 37 can faithfully display the image as shown in Figure 3, and the situation as shown in Figure 4A will not occur.

Based on the consideration of simplified design, in actual application, the auxiliary scanning signals eSR[1]~eSR[4] can be pulled up synchronously at the beginning of the panel light intensity sensing period pT_m3 (time point t3), and the auxiliary scanning signals eSR[1]~eSR[4] can be pulled high when the panel light intensity sensing period starts. During the measurement period, pT_m3 is maintained at 4V at the same time. After the panel light intensity sensing period pT_m3 ends (time point t4), the auxiliary scanning signals eSR[1]~eSR[4] are synchronously pulled back to -7V.

When the auxiliary scanning signals eSR[1]~eSR[4] are generated in a synchronous manner, the read transistors T1(m,1)~T1(m,2) will be turned on at the same time, and the light intensity sensing signal expDET[m] The voltage is also affected by the read transistors T1(m,1)~T1(m,2). Therefore, the digital sensing signal expDET_d[m] converted according to the light intensity sensing signal expDET[m] reflects a result that is jointly affected by the light sensing elements lgtSU(m,1)~lgtSU(m,4). Therefore, although the controller 43 can know that there is an overexposure situation somewhere among the light sensing elements lgtSU(m,1)~lgtSU(m,4), it cannot clearly know the light sensor where the overexposure phenomenon occurs. The number of columns (the value of n) where the element lgtSU(m,n) is located.

In Figure 11, a variable x represents the number of times sensing is performed. Time points t1 to t6 correspond to the sensing period T _cyc [x] for the x-th sensing, and time point t6 starts as the sensing period T _cyc [x+1] for the (x+1)-th sensing. Among them, time points t5 to t6 are the element reading period uT_m5 in the sensing period T _cyc [x], and are also the element reset period uT_m1 in the sensing period T _cyc [x+1]. That is, two consecutive sensing periods T _cyc [x] and T _cyc [x+1] may partially overlap.

Please refer to Figure 12, which is a schematic diagram of combining the sensing circuit and the reading circuit using a multiplexer. The connection methods of the light sensing elements lgtSU(m,1)~lgtSU(m,4) in this figure are similar to those in Figure 8. What is different from Figure 8 is that in Figure 12, the reading circuit 413 and the light intensity sensing circuit 45 are not provided independently, but a light intensity sensing and image reading system that combines the light intensity sensing function and the reading function is provided. Take circuit 513 and use it with multiplexer 53.

The multiplexer 53 includes a PMOS transistor Mp and an NMOS transistor Mn. The gates of the PMOS transistor Mp and the NMOS transistor are controlled by the function selection signal fsS[m]. The controller 515 may optionally change the voltage of the function selection signal fsS[m] and selectively turn on one of the PMOS transistor Mp and the NMOS transistor Mn. For example, when the function selection signal fsS[m] is a high logic level, the NMOS transistor Mn is turned on and the PMOS transistor Mp is turned off; when the function selection signal fsS[m] is a low logic level, the PMOS transistor Mp is turned on and the NMOS transistor Mp is turned off. Transistor Mn is disconnected.

The light intensity sensing signal line expDET[m] and the data reading signal line rdDAT[m] are both electrically connected to the multiplexer 53 . When the PMOS transistor Mp is turned on, the data selection signal selDAT[m] received by the light intensity sensing and image reading circuit 513 from the multiplexer 53 is the light intensity sensing signal line expDET[m]. On the other hand, when the NMOS transistor Mn is turned on, the data selection signal selDAT[m] received by the light intensity sensing and image reading circuit 513 from the multiplexer 53 is the data reading signal rdDAT[m].

The light intensity sensing and image reading circuit 513, which has both the light intensity sensing function and the reading function, receives the data selection signal selDAT[m] from the multiplexer 53, and first uses the integrator 513a to convert Change to analog data selection signal selDAT_a[m]. After that, the analog-to-digital converter 513c is used to convert the analog data selection signal selDAT_a[m] into the digital data selection signal selDAT_d[m]. When the controller 515 receives the digital data selection signal selDAT_d[m] from the analog-to-digital converter 513c, the source of the digital data selection signal selDAT_d[m] is the light intensity sensing signal line expDET[m] or the data reading signal line. rdDAT[m] for subsequent control.

Please also note that it is assumed here that the light intensity sensing signal line expDET[m] is electrically connected to the PMOS transistor Mp, and the data reading signal line rdDAT[m] is electrically connected to the NMOS transistor Mn. However, in actual applications, the internal design of the multiplexer 53 and how it is connected to the light intensity sensing signal line expDET[m] and the data reading signal line rdDAT[m] are not limited to this.

As mentioned above, the sensing panel according to the present disclosure pre-senses the voltage at the sensing terminal Np(m,n) before actually reading, and then pre-changes the voltage before reading based on the sensing result. The voltage of the main scanning signal mSR[n] (-8V→-9V) connected to the light sensing element that would otherwise be overexposed reduces the leakage current generated by the read transistor T1(m,n).

By pre-sensing and pre-adjusting the gate voltage, it is possible to prevent leakage current from affecting other photo-sensing elements due to overexposure of some photo-sensing elements. Moreover, when the concept of this project is adopted, the waveform of the data read signal rdDAT[m] will not be changed. Therefore, the situation that affects the presentation of details as described in Figure 4B will not occur, and the accuracy of the sensed image can be maintained.

In summary, although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the appended patent application scope.

3:Light sensing system

33:Light source

31:Light sensing device

37:Display panel

315:Controller

319a: Main selection circuit

319c: Auxiliary selection circuit

311: Sensing panel

313:Image reading circuit

317:Light intensity sensing circuit

38: Bias circuit

lgtctlS: light source control signal

rdDAT_d[1]~rdDAT_d[M]: digital read signal

mctlS,ectlS: column selection control signal

mSR[1]~mSR[N]: main scanning signal

eSR[1]~eSR[N]: auxiliary scanning signal

Vbs: bias signal (line)

expDET[1]~expDET[M]: light intensity sensing signal

bsES: bias enable signal

expDET_d[1]~expDET_d[M]: digital sensing signal

Claims (10)

A light sensing element electrically connected to a data reading signal line, a light intensity sensing signal line, a main scanning signal line and an auxiliary scanning signal line, including: a photosensitive circuit electrically connected to a sensing terminal and the auxiliary scanning signal line, which senses an illumination intensity during an illumination period, so that the voltage of the sensing endpoint changes with the illumination intensity; a sensing transistor, electrically connected between the sensing endpoint and The light intensity sensing signal line changes the voltage of the light intensity sensing signal line according to the voltage of the sensing terminal during a light intensity sensing period, and the voltage of the main scanning signal line changes during a compensation period. , selectively changed in response to the voltage of the light intensity sensing signal line; and, a reading transistor, electrically connected to the sensing endpoint, the data reading signal line and the main scanning signal line, which is connected to a During the reading period, the main scanning signal line is turned on according to the pulse wave, so that the data reading signal line reflects the voltage of the sensing endpoint, wherein the light intensity sensing period is later than the illumination period and the compensation period is later During the light intensity sensing period, and the reading period is later than the compensation period. The light sensing element of claim 1, wherein the main scanning signal line generates a pulse wave that turns on the reading transistor during a reset period, and the voltage of the sensing terminal increases during the reset period. to a reset voltage, wherein the illumination period is later than the reset period. The light sensing element of claim 2, wherein the sensing transistor remains disconnected during the reset period, the illumination period, the compensation period and the reading period. The light sensing element as described in claim 2, wherein the light sensing circuit includes: a photodiode, electrically connected to the sensing endpoint and the auxiliary scanning signal line; and, a capacitor, electrically connected to the sensing endpoint. The detection endpoint and the auxiliary scanning signal line are charged through the conduction of the reading transistor during the reset period. The light sensing element of claim 1, wherein the reading transistor remains turned off during the illumination period, the light intensity sensing period and the compensation period. The light sensing element of claim 1, wherein the sensing transistor is electrically connected to a bias signal line, wherein the voltage of the bias signal line during the light intensity sensing period is higher than during the illumination period. and the voltage during this compensation period. The light sensing element of claim 6, wherein during the light intensity sensing period, the sensing transistor selectively conducts the voltage of the bias signal line to the light intensity in response to the voltage of the sensing terminal. Sensing signal line. The light sensing element of claim 1, wherein when the light intensity is stronger, the voltage of the light intensity sensing signal line during the light intensity sensing period is lower, and When the voltage of the light intensity sensing signal line is lower than a preset threshold, the main scanning signal line switches from a first voltage to a second voltage during the compensation period, wherein the first voltage is higher than the second voltage. ; And, when the light intensity sensing signal line is higher than or equal to the preset threshold, the main scanning signal line is maintained at the first voltage during the compensation period. A sensing panel, electrically connected to a controller, including: a plurality of light sensing elements arranged in M rows and N columns, wherein a first light sensing element among the light sensing elements is located at an mth row and an n-th column, and the first light sensing element is electrically connected to an m-th row data reading signal line, an m-th row light intensity sensing signal line, an n-th column main scanning signal line and an The nth column of auxiliary scanning signal lines, wherein the first light sensing element includes: a photosensitive circuit electrically connected to a sensing terminal and the nth column of auxiliary scanning signal lines, which senses a The intensity of light causes the voltage of the sensing terminal to change with the intensity of light; a sensing transistor is electrically connected to the sensing terminal and the m-th row of light intensity sensing signal lines, which are connected to a light During the intensity sensing period, the voltage of the light intensity sensing signal line of the m-th row is changed in response to the voltage of the sensing terminal, and the voltage of the main scanning signal line of the n-th column is changed in response to the light intensity of the m-th row during a compensation period. The voltage of the sensing signal line is selectively changed; and, a reading transistor is electrically connected to the sensing terminal, the m-th row data reading signal line and the main scanning signal line, which is connected to a reading During this period, it is turned on according to the pulse wave of the main scanning signal line of the nth column, so that the data reading signal line of the mth row reflects the voltage of the sensing endpoint, wherein the controller reads the data of the mth row according to the The voltage of the signal line during the reading period generates image data corresponding to the first light sensing element, wherein the light intensity sensing period is later than the illumination period, and the compensation period is later than the light intensity sensing period. , and the reading period is later than the compensation period, where M, N, m, and n are positive integers, m is less than or equal to M, and n is less than or equal to N. The sensing panel as claimed in claim 9, wherein a second light sensing element among the light sensing elements is located in the mth row and an (n+1)th column, and the light sensing elements A third light sensing element is located in a (m+1)th row and the nth column, wherein the second light sensing element is electrically connected to the mth row data reading signal line, the mth Row light intensity sensing signal lines, an (n+1)th column main scanning signal line and an (n+1)th column auxiliary scanning signal line, and the third light sensing element is electrically connected to an (m+1)th column +1) row data reading signal line, a (m+1)th row light intensity sensing signal line, the nth column main scanning signal line and the nth column auxiliary scanning signal line.