CN112135014A - Signal acquisition device - Google Patents

Abstract

A signal acquisition device comprising: a controller for receiving a first electrical signal generated by the image sensor, the first electrical signal being obtained by converting signal light and ambient light; an ambient sensor for generating a second electrical signal, the second electrical signal being obtained by conversion of the ambient light; wherein the controller is further coupled to the environmental sensor to receive the second electrical signal and calculate a third electrical signal from the first and second electrical signals, the third electrical signal being indicative of the electrical signal obtained by the signal light conversion. The scheme provided by the invention can effectively eliminate the influence of ambient light on the image acquisition result and improve the imaging quality.

Description

A signal acquisition device

technical field

The present invention relates to the technical field of image sensors, in particular to a signal acquisition device.

Background technique

An image sensor is a sensor device that uses the photoelectric conversion function of a photoelectric device to convert the light image on the photosensitive surface into an electrical signal that is proportional to the light image.

Taking an optical fingerprint sensor as an example, it is usually composed of a pixel array, and each pixel in the pixel array has a photosensitive element to realize the conversion of optical signals into electrical signals.

At present, image sensors are continuously developing in the direction of large size, high resolution, high image quality and low cost. In addition, in recent years, due to the vigorous development of artificial intelligence, the information obtained by the image becomes more important, which puts forward higher requirements for the resolution and imaging quality of the image sensor.

Existing optoelectronic devices applied to image sensors are usually photodiodes (Photo-Diodes), which are inevitably affected by interference factors such as ambient light during operation, resulting in poor imaging quality.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is how to eliminate the influence of ambient light on the image acquisition result and improve the imaging quality.

To solve the above technical problem, an embodiment of the present invention provides a signal acquisition device, including: a controller for receiving a first electrical signal generated by an image sensor, where the first electrical signal is obtained by converting signal light and ambient light; a sensor for generating a second electrical signal, the second electrical signal is obtained by converting the ambient light; wherein the controller is further coupled with the ambient sensor to receive the second electrical signal, and according to the The first electrical signal and the second electrical signal are calculated to obtain a third electrical signal, and the third electrical signal is used to represent the electrical signal obtained by converting the signal light.

Optionally, the controller and the environmental sensor are integrated in the same semiconductor chip.

Optionally, the calculating and obtaining the third electrical signal according to the first electrical signal and the second electrical signal includes: receiving the first electrical signal; receiving the second electrical signal; modifying to obtain a fourth electrical signal; and determining the difference between the first electrical signal and the fourth electrical signal as the third electrical signal.

Optionally, the modifying the second electrical signal to obtain the fourth electrical signal includes: according to the proportional relationship between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element, and the second electric signal. signal to determine the fourth electrical signal, wherein the second photosensitive element is used to generate the second electrical signal, and the first photosensitive element is used to generate the first electrical signal.

Optionally, the second photosensitive element is integrated with the environment sensor, and the number of the second photosensitive element is one.

Optionally, the environmental sensor includes a plurality of second photosensitive elements, and the second photosensitive elements are used to generate the second electrical signal.

Optionally, the modifying the second electrical signal to obtain the fourth electrical signal includes: generating a pre-processed second electrical signal based on the second electrical signals each generated by the plurality of second photosensitive elements; The proportional relationship between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element, and the preprocessed second electrical signal, determine the fourth electrical signal, wherein the first photosensitive element is used to generate all the first electrical signal.

Optionally, the generating the pre-processed second electrical signal based on the second electrical signals generated by the plurality of second photosensitive elements respectively includes: determining an average value of the plurality of second electrical signals as the pre-processed second electrical signal. signal; or, determining the minimum value among the plurality of second electrical signals as the preprocessed second electrical signal; or, determining the second electrical signal with the largest occurrence probability of the value among the plurality of second electrical signals as the preprocessed second electrical signal The second electrical signal is processed.

Optionally, the environment sensor is independent from the controller, and a plurality of second photosensitive elements are distributed at different positions on the plane where the image sensor is located.

Optionally, the distance between the environment sensor and the image sensor is not greater than 5 cm.

Optionally, the image sensor includes a plurality of pixels arranged in an array, wherein each pixel includes a first photosensitive element and a pixel switch connected in series, and the first photosensitive element is used for generating the first electrical signal.

Optionally, the pixel further includes a buffer and an amplifier.

Optionally, the image sensor further includes: a plurality of data lines, wherein, in each row of pixels, each pixel is connected to the same data line, and the first electrical signal generated by the first photosensitive element in each pixel passes through the The pixel switch is transmitted to the data line, and the output end of the data line is coupled to the controller.

Compared with the prior art, the technical solutions of the embodiments of the present invention have the following beneficial effects:

An embodiment of the present invention provides a signal acquisition device, including: a controller coupled to an image sensor to receive a first electrical signal generated by the image sensor, where the first electrical signal is obtained by converting signal light and ambient light; an environmental sensor for acquiring a second electrical signal, where the second electrical signal is obtained by converting the ambient light; wherein the controller is further coupled with the environmental sensor to receive the second electrical signal, and according to The first electrical signal and the second electrical signal are calculated to obtain a third electrical signal, and the third electrical signal is used to represent the electrical signal obtained by converting the signal light. Compared with the prior art, the image sensing system according to the embodiment of the present invention can effectively eliminate the influence of ambient light on the image acquisition result, and improve the imaging quality. Specifically, on the basis of not changing the device structure of the existing image sensor, the ambient light is separately collected by adding an environmental sensor to correct the first electrical signal output by the image sensor, thereby suppressing the imaging of the image sensor by the ambient light. impact on results.

Further, the controller and the environmental sensor are integrated in the same semiconductor chip. Therefore, by fine-tuning the original signal acquisition device for reading and processing the output signal of the image sensor, the influence of ambient light on the imaging result can be effectively corrected, and an image with higher quality can be obtained. Further, the signal acquisition device in this embodiment can be compatible with the existing image sensor, without the need for additional improvement of the image sensor, and the implementation cost is low.

Description of drawings

1 is a schematic diagram of a signal acquisition device according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a calculation flow of a third electrical signal in the embodiment shown in FIG. 1;

3 is a schematic diagram of a signal acquisition device according to a second embodiment of the present invention;

Fig. 4 is a flow chart of a specific implementation of step S103 in Fig. 2;

FIG. 5 is a schematic diagram of a signal acquisition device according to a third embodiment of the present invention.

Detailed ways

As mentioned in the background art, the existing optoelectronic devices used in image sensors are usually photodiodes (Photo-Diodes), which are inevitably affected by interference factors such as ambient light during operation, resulting in poor image quality.

In order to solve the above technical problem, an embodiment of the present invention provides a signal acquisition device, including: a controller coupled to an image sensor to receive a first electrical signal generated by the image sensor, the first electrical signal being generated by a signal light and the ambient light is converted and obtained; an environmental sensor is used to obtain a second electrical signal, and the second electrical signal is obtained by converting the ambient light; wherein the controller is further coupled with the environmental sensor to receive the first electrical signal. Two electrical signals, and a third electrical signal is calculated according to the first electrical signal and the second electrical signal, and the third electrical signal is used to represent the electrical signal obtained by optical conversion of the signal.

Those skilled in the art understand that the image sensing system according to the embodiment of the present invention can effectively eliminate the influence of ambient light on the image acquisition result, and improve the imaging quality. Specifically, on the basis of not changing the device structure of the existing image sensor, the ambient light is separately collected by adding an environmental sensor to correct the first electrical signal output by the image sensor, thereby suppressing the imaging of the image sensor by the ambient light. impact on results.

In order to make the above objects, features and beneficial effects of the present invention more clearly understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a signal acquisition device according to the first embodiment of the present invention.

The signal acquisition device 1 in this embodiment can be applied to an image acquisition scenario, such as an optical fingerprint acquisition scenario. The signal acquisition device 1 may be coupled with an image sensor 2 to receive image information collected by the image sensor 2, where the image information may be an optical fingerprint image, and the image sensor 2 may be an optical fingerprint sensor.

In order to show the device structure more clearly, the image sensor 2 in FIG. 1 only shows the specific structure of a single pixel in the pixel array.

Specifically, the signal acquisition device 1 in this embodiment may include: a controller 10 configured to receive a first electrical signal generated by the image sensor 2, where the first electrical signal is obtained by converting signal light and ambient light; an environmental sensor 11 , for generating a second electrical signal, the second electrical signal is obtained by converting the ambient light; wherein, the controller 10 is further coupled with the ambient sensor 11 to receive the second electrical signal, and according to The first electrical signal and the second electrical signal are calculated to obtain a third electrical signal, and the third electrical signal is used to represent the electrical signal obtained by converting the signal light.

In a specific implementation, the image sensor 2 may include a plurality of pixels 20 arranged in an array, wherein each pixel 20 includes a first photosensitive element 201 and a pixel switch 202 connected in series, and the first photosensitive element 201 is used to generate the first electrical signal.

In a specific implementation, the image sensor 2 may further include: a plurality of data lines (marked by c1 to cn in the figure), wherein, in each row of pixels 20, each pixel 20 is connected to the same data line ci, The first electrical signal generated by the first photosensitive element 201 in each pixel 20 is transmitted to the data line ci through the pixel switch 202, and the output end of the data line ci is coupled to the controller 10, 1≤i≤ n, i are positive integers.

The output ends of different data lines ci are respectively coupled to different ports of the controller 10 . Thus, the controller 10 can respectively receive and process the first electrical signals transmitted by the respective data lines ci.

In a specific implementation, the environmental sensor 11 may include a second photosensitive element 110 for generating the second electrical signal.

In a specific implementation, the pixel switch 202 is usually a thin film transistor (Thin Film Transistor, TFT for short) device, and the photosensitive element is used to collect externally input light signals, convert them into electrical signals, and then store them in corresponding pixels. In this embodiment, the optical signal collected by the first photosensitive element 201 includes an ambient light signal and a signal light signal, and the collected optical signal is converted into a first electrical signal and stored in the corresponding pixel 20; The light signal collected by the two photosensitive elements 110 includes the ambient light signal, and the collected light signal is converted into a second electrical signal and output. In an optical fingerprint collection scenario, the signal light signal carries fingerprint information.

In a specific implementation, the first photosensitive element 201 and the second photosensitive element 110 may be photodiodes. The photodiodes may include PIN junction amorphous silicon photodiodes, PN junction amorphous silicon photodiodes, PIN junction low temperature polysilicon photodiodes, PN junction low temperature polysilicon photodiodes, PIN junction organic photodiodes, or PN junction organic photodiodes, and the like.

In a specific implementation, the controller 10 and the environmental sensor 11 may be integrated into the same semiconductor chip. Therefore, by fine-tuning the original signal acquisition device 1 for reading and processing the output signal of the image sensor 2, the influence of ambient light on the imaging result can be effectively corrected, and an image with higher quality can be obtained. Further, the signal acquisition device 1 in this embodiment can be compatible with the existing image sensor 2 , no additional improvement of the image sensor 2 is required, and the implementation cost is low.

For example, the environmental sensor 11 may be integrated on an existing control chip for reading and processing the image signals collected by the image sensor 2 to acquire the second electrical signal, and based on the second electrical signal The first electrical signal is corrected to obtain the third electrical signal.

In a specific implementation, referring to FIG. 1 , the number of the second photosensitive element 201 may be one, and the controller 10 may include a control unit (Control Unit) 101 for generating the second photosensitive element 201 The second electrical signal is subjected to data processing operations such as analog-to-digital conversion (Analogue-to-Digital Conversion, ADC for short).

In a specific implementation, referring to FIG. 2 , the calculating and obtaining the third electrical signal according to the first electrical signal and the second electrical signal may include the following steps:

Step S101, receiving the first electrical signal;

Step S102, receiving the second electrical signal;

Step S103, modifying the second electrical signal to obtain a fourth electrical signal;

Step S104, determining the difference between the first electrical signal and the fourth electrical signal as the third electrical signal.

In a specific implementation, the step S101 and the step S102 may be executed synchronously or asynchronously, and when the step S101 and the step S102 are executed asynchronously, the sequence of execution of the step S101 and the step S102 may be interchanged.

In a specific implementation, the step S103 may include the step of: determining the fourth electrical signal according to the proportional relationship between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element, and the second electrical signal.

For example, the third electrical signal can be calculated based on the following formula:

I _out =I ₁ -αI ₂ ;

Wherein, I _out is the third electrical signal; I ₁ is the first electrical signal; α is the proportional relationship between the photosensitive area of the second photosensitive element 110 and the photosensitive area of the first photosensitive element 201 ; _I2 is the second electrical signal; αI ₂ is the fourth electrical signal.

In a specific implementation, the second photosensitive element 110 and the first photosensitive element 201 may use photodiodes of different specifications. For example, the photosensitive area of the second photosensitive element 110 may be larger than that of the first photosensitive element 201 . , to ensure that the ambient light signal of the image sensor 2 is effectively collected. The difference in the sensing results of ambient light caused by different photosensitive areas can be corrected by the proportional relationship between the photosensitive area of the second photosensitive element 110 and the photosensitive area of the first photosensitive element 201, so that the The four electrical signals can basically eliminate the ambient light signal part in the first electrical signal transmitted by the data line ci.

In a specific implementation, the controller 10 may further include a current source 102 for receiving the fourth electrical signal. The current sources 102 can be in one-to-one correspondence with the data lines ci to receive the first electrical signal transmitted by the corresponding data lines ci, and each current source 102 is coupled to the control unit 101 to receive the first electrical signal. Four electrical signals.

For each data line ci, the photocurrent finally output by the data line ci (ie, the third electrical signal) is a superimposed signal of the corresponding first electrical signal and the fourth electrical signal received by the corresponding current source 102 . That is, the difference between the first electrical signal and the fourth electrical signal.

In a variation example, the photosensitive area of the second photosensitive element 110 may be the same as the photosensitive area of the first photosensitive element 201 , and correspondingly, the proportional relationship α may be 1.

In a specific implementation, the distance between the environmental sensor 11 and the image sensor 2 is not greater than 5 cm, so as to ensure that the second photosensitive element 110 can effectively collect the ambient light signal of the environment where the image sensor 2 is located .

From the above, with the solution of this embodiment, the influence of ambient light on the image acquisition result can be effectively eliminated, and the imaging quality can be improved. Specifically, on the basis of not changing the device structure of the existing image sensor 2, the ambient light is separately collected by adding an environmental sensor 11 to correct the first electrical signal output by the image sensor 2, thereby suppressing the effect of ambient light on the image. Influence of the imaging result of sensor 2.

FIG. 3 is a schematic diagram of a signal acquisition device according to a second embodiment of the present invention. In the following detailed description, descriptions of matters and features common to the first embodiment shown in FIG. 1 are omitted, and only different points are described. In particular, the same functions and effects produced by the same structure will not be mentioned one by one in each embodiment. In each figure, the same reference numerals are attached to the same parts.

Next, only the differences between the second embodiment and the first embodiment shown in FIG. 1 will be described in detail.

In this embodiment, the main difference from the above-mentioned signal acquisition device 1 shown in FIG. 1 is that the environmental sensor 11 may be an independent device from the controller 10 .

For example, in the application scenario of optical fingerprint recognition on a smart terminal such as a mobile phone, the environmental sensor 11 can reuse the existing ambient light sensing unit on the mobile phone, and the controller 10 can communicate with the ambient light sensing unit It is coupled to receive the second electrical signal, and based on the second electrical signal, the first electrical signal collected by the image sensor 2 is corrected.

In a specific implementation, for example, when the environment sensor 11 is an existing module on a multiplexed smart terminal, the environment sensor 11 may include a plurality of second photosensitive elements 110 .

Further, the plurality of second photosensitive elements 110 may be distributed at different positions on the plane where the image sensor 2 is located. For example, the plurality of second photosensitive elements 110 may be disposed around the image sensor 2 to uniformly and comprehensively collect ambient light signals of the environment where the image sensor 2 is located.

In a specific implementation, referring to FIG. 4 , the step S103 may include the following steps:

Step S1031, generating a preprocessed second electrical signal based on the second electrical signals generated by the plurality of second photosensitive elements respectively;

Step S1032: Determine the fourth electrical signal according to the proportional relationship between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element, and the preprocessed second electrical signal.

For example, the control unit 101 can perform analog-to-digital conversion and data operation operations on the plurality of second electrical signals, so as to integrate and process the plurality of second electrical signals into a value proportional to the actual location of the image sensor 2 The electrical signal of ambient light, the electrical signal is the preprocessed second electrical signal.

In a specific implementation, the step S1031 may include the step of: determining an average value of a plurality of second electrical signals (as shown in the figure I ₂ to I ₅ ) as the preprocessed second electrical signal. Therefore, by synthesizing the ambient light signals collected by the second photosensitive elements 110 disposed at different positions on the periphery of the image sensor 2, the average ambient light signal of the image sensor 2 can be obtained to ensure the ambient light represented by the fourth electrical signal. The signal is as close as possible to the actual ambient light of the environment where the image sensor 2 is located, to ensure that the third electrical signal obtained by the final offset can truly retain the signal light signal sensed by the image sensor 2, that is, not much deduction, and also No ambient light signal remains.

In a variation example, the step S1031 may include the step of: determining the minimum value among the plurality of second electrical signals as the preprocessed second electrical signal, so as to avoid excessive correction and affect the image quality.

In a variant example, the step S1031 may include the step of: determining a second electrical signal with the largest occurrence probability of a numerical value among the plurality of second electrical signals as the preprocessed second electrical signal. This also has the effect of avoiding overcorrection.

In a specific implementation, the step S1032 can be expressed based on the following formula:

I _out =I ₁ -αI ₃ ;

Wherein, I _out is the third electrical signal; I ₁ is the first electrical signal; α is the proportional relationship between the photosensitive area of the second photosensitive element 110 and the photosensitive area of the first photosensitive element 201 ; _I3 is The preprocessed second electrical signal; αI ₃ is the fourth electrical signal.

In a variation example, the photosensitive areas of the second photosensitive elements 110 may be different, and accordingly, the proportional relationship α may be determined according to the average value of the photosensitive areas of the second photosensitive elements 110 .

FIG. 5 is a schematic diagram of a signal acquisition device according to a third embodiment of the present invention.

In this embodiment, the main difference from the signal acquisition device 1 shown in FIG. 1 and FIG. 3 is that: for the image sensor 3 coupled to the signal acquisition device 1 shown in FIG. 5 , in addition to the first photosensitive element 201 and In addition to the pixel switch 202 , each pixel 30 included in the image sensor 3 may further include a buffer 203 and an amplifier 204 .

The buffer 203 may be a capacitor to store the first electrical signal converted by the corresponding first photosensitive element 201 ; the amplifier 204 may be a TFT. Therefore, the pixels 30 are active pixels, and the image sensor 3 is an active image sensor.

In a specific implementation, each of the second photosensitive elements 110 may also be correspondingly coupled to an amplifier (not shown) and a buffer (not shown) to buffer and amplify the collected second electrical signals.

Correspondingly, the controller 10 can comprehensively determine the proportional relationship α according to factors such as the photosensitive area, the voltage and size of the amplifier coupled to the second photosensitive element 110 .

Although the above embodiments connect the data lines ci in units of rows, in practical applications, for the pixel array formed by the plurality of pixels 20, the concepts of row and column can be interchanged. That is, for each data line ci, the data line ci may be coupled to a plurality of pixels 20 of the corresponding column.

In a specific implementation, the controller 10 may be an integrated circuit chip (Integrated Circuit, IC for short).

Although the present invention is disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be based on the scope defined by the claims.

Claims (13)

1. A signal acquisition device, comprising:

a controller for receiving a first electrical signal generated by the image sensor, the first electrical signal being obtained by converting signal light and ambient light;

an ambient sensor for generating a second electrical signal, the second electrical signal being obtained by conversion of the ambient light;

wherein the controller is further coupled to the environmental sensor to receive the second electrical signal and calculate a third electrical signal from the first and second electrical signals, the third electrical signal being indicative of the electrical signal obtained by the signal light conversion.

2. The signal acquisition device of claim 1 wherein the controller is integrated with the environmental sensor on the same semiconductor chip.

3. The signal acquisition device of claim 1, wherein calculating a third electrical signal from the first and second electrical signals comprises:

receiving the first electrical signal;

receiving the second electrical signal;

correcting the second electric signal to obtain a fourth electric signal;

determining a difference of the first electrical signal and the fourth electrical signal as the third electrical signal.

4. The signal acquisition device of claim 3, wherein the modifying the second electrical signal to obtain a fourth electrical signal comprises:

and determining the fourth electric signal according to the proportional relation between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element and the second electric signal, wherein the second photosensitive element is used for generating the second electric signal, and the first photosensitive element is used for generating the first electric signal.

5. The signal acquisition device of claim 4 wherein the second photosensitive elements are integrated with the environmental sensor and the number of the second photosensitive elements is 1.

6. The signal acquisition device of claim 3 wherein the environmental sensor comprises a plurality of second photosensitive elements for generating the second electrical signal.

7. The signal acquisition device of claim 6, wherein the modifying the second electrical signal to obtain a fourth electrical signal comprises:

generating a preprocessed second electrical signal based on the second electrical signals generated by each of the plurality of second photosensitive elements;

and determining the fourth electric signal according to the proportional relation between the photosensitive area of the second photosensitive element and the photosensitive area of the first photosensitive element and the preprocessed second electric signal, wherein the first photosensitive element is used for generating the first electric signal.

8. The signal acquisition device of claim 7 wherein the generating a pre-processed second electrical signal based on the second electrical signal generated by each of the plurality of second photosensitive elements comprises:

determining an average of a plurality of second electrical signals as the pre-processed second electrical signal; or,

determining a minimum value of a plurality of second electrical signals as the pre-processed second electrical signal; or,

and determining the second electric signal with the highest numerical occurrence probability in the plurality of second electric signals as the preprocessed second electric signal.

9. The signal acquisition device of claim 6, wherein the environmental sensor is independent of the controller, and the plurality of second photosensitive elements are distributed at different positions in a plane of the image sensor.

10. The signal acquisition device of claim 1 wherein the distance between the environmental sensor and the image sensor is no greater than 5 centimeters.

11. The signal acquisition device according to any one of claims 1 to 10, wherein the image sensor comprises a plurality of pixels arranged in an array, wherein each pixel comprises a first photosensitive element and a pixel switch connected in series, and the first photosensitive element is configured to generate the first electrical signal.

12. The signal acquisition device of claim 11 wherein the pixel further comprises a buffer and an amplifier.

13. The signal acquisition device of claim 11, wherein the image sensor further comprises:

and a plurality of data lines, wherein in each row of pixels, each pixel is connected with the same data line, a first electric signal generated by the first photosensitive element in each pixel is transmitted to the data line through the pixel switch, and the output end of the data line is coupled to the controller.

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