KR102717141B1 - Active matrix circuit for high-speed driving of light-receiving diode array and method for operating the same - Google Patents

Abstract

An active matrix circuit for high-speed driving of a photodiode array and a driving method thereof are disclosed. A photodiode array capable of high-speed driving according to one embodiment of the present invention may include a photodiode that generates a photocurrent corresponding to incident light, a first switch that connects an output signal of the photodiode to a signal readout line based on a control signal, and a second switch that applies a preset bias voltage to the photodiode based on the control signal.

Description

{ACTIVE MATRIX CIRCUIT FOR HIGH-SPEED DRIVING OF LIGHT-RECEIVING DIODE ARRAY AND METHOD FOR OPERATING THE SAME}

The present invention relates to an active matrix circuit for high-speed driving of a photodiode array and a driving method thereof. For example, the present invention relates to a photodiode array capable of high-speed driving and an active matrix circuit structure including the same.

Organic electronic devices have been mainly developed with a limited scope, such as light-emitting diodes and solar cells, but recently, the development of photodiode devices based on organic materials has been expanding. This is because organic-based photodiodes have a good absorption spectrum from the ultraviolet wavelength band to the near-infrared wavelength band, and compared to inorganic semiconductors, they have relatively low-temperature process capabilities, so they can accommodate most substrate processes, and thus have the advantage of making optical imaging and bio-fusion products a reality.

Meanwhile, Fig. 1 is a drawing showing a conventional active matrix structure. Referring to Fig. 1, a conventional active matrix structure may be composed of a photodetector diode and a switching element for selecting the photodetector diode, and the switching element is controlled using a control signal line shared in a row unit, and the output of the switching element is transmitted to a column-unit signal line shared in a column unit and received in a column-unit reader.

Specifically, since the photodiode generates a photocurrent linearly proportional to the incident light when a reverse bias of a predetermined size or greater is applied, in a column-by-column reader (Col Readout), the column-by-column signal line is biased to a specific voltage, and at this time, the longer the signal line, the longer it takes to charge the cathode voltage of the photodiode by the RC (resistor-capacitor) value of the signal line.

In this regard, Fig. 2 is a graph comparing the current-voltage characteristics of a silicon type photodiode and an organic photodiode.

Referring to FIG. 2, if the photodetector is a silicon-based diode having current-voltage (I-V) characteristics as in (a) of FIG. 2, sufficient photocurrent is generated even at low reverse bias, so that sufficient photocurrent is transmitted to the column-unit reader while the cathode voltage of the photodetector is charged. On the other hand, if the photodetector is an organic diode type as in (b) of FIG. 2, sufficient photocurrent cannot be generated at low reverse bias, so there is a problem of reducing the operating speed of the active matrix.

The background technology of this application is disclosed in Korean Patent Publication No. 10-2022-0108608.

The present invention is intended to solve the problems of the above-mentioned prior art, and to provide an active matrix circuit for high-speed driving of a photodiode array that can be controlled using the same row-by-row control signal by making a first switch for reading the output of the photodiode and a second switch for providing a bias voltage to the photodiode operate complementarily to each other, and a driving method thereof.

The present invention is intended to solve the problems of the above-mentioned prior art, and to provide an active matrix circuit for high-speed driving of a photodiode array capable of high-speed operation by biasing the photodiode with a second switch even when the first switch does not operate, thereby not requiring a separate charging time for the photodiode, and thus immediately generating an output signal after the corresponding photodiode is selected, and a driving method thereof.

However, the technical tasks to be achieved by the embodiments of the present invention are not limited to the technical tasks described above, and other technical tasks may exist.

As a technical means for achieving the above-mentioned technical task, a high-speed driving photodiode array according to one embodiment of the present invention may include a photodiode that generates a photocurrent corresponding to incident light, a first switch that connects an output signal of the photodiode to a signal readout line based on a control signal, and a second switch that applies a preset bias voltage to the photodiode based on the control signal.

Additionally, the first switch and the second switch can operate complementarily based on the control signal.

Additionally, when the first switch is turned on according to the control signal, the second switch is turned off, and the output signal can be transmitted to the reading module through the signal reading line.

Additionally, when the second switch is turned on according to the control signal, the first switch is turned off, and the cathode voltage of the photodetector can be charged based on the bias voltage.

Additionally, when the first switch is turned on according to the control signal, a reverse bias that can generate the photocurrent can be formed in the photodetector diode.

Additionally, the first switch may be one of an N-type transistor and a P-type transistor, and the second switch may be the other of the N-type transistor and the P-type transistor.

Additionally, the photodetector may be an organic photodetector.

Meanwhile, an active matrix circuit for high-speed driving of a photodiode array according to one embodiment of the present invention may include a photodiode, each of which generates a photocurrent corresponding to incident light, a first switch for connecting an output signal of the photodiode to a signal readout line based on a control signal, and a second switch for applying a preset bias voltage to the photodiode based on the control signal, and may include a plurality of array cells arranged to form a matrix by forming a plurality of rows and a plurality of columns, a control module for applying the control signal to each of the plurality of rows of the plurality of array cells, a bias module for applying the bias voltage corresponding to each of the plurality of columns of the plurality of array cells, and a readout module for obtaining the output signal from each of the plurality of columns of the plurality of array cells.

Additionally, the bias module can be connected to the second switch and bias line of the array cell included in each of the plurality of columns.

Additionally, the reading module can be connected to the first switch and signal reading line of the array cells included in each of the plurality of columns.

In addition, the first switch and the second switch provided for each of the plurality of array cells can operate complementarily based on the control signal.

In addition, when the first switch of one of the plurality of array cells is turned on according to the control signal, the second switch of the one of the array cells is turned off, and the output signal can be transmitted to the reading module through the signal reading line corresponding to the one of the array cells.

In addition, when the second switch of one of the plurality of array cells is turned on according to the control signal, the first switch of the one of the array cells is turned off, and the cathode voltage of the photodetector of the one of the array cells can be charged based on the bias voltage.

In addition, when the first switch of one of the array cells is turned on according to the control signal, a reverse bias that can generate the photocurrent can be formed in the photoreceiving diode of the one of the array cells.

Meanwhile, a method for driving a photodiode array capable of high-speed operation according to one embodiment of the present invention may include a step of charging a cathode voltage of the photodiode based on the bias voltage by turning on the second switch based on the control signal, and a step of transmitting an output signal of the photodiode through the signal readout line by turning on the first switch based on the control signal.

The above-described problem solving means are merely exemplary and should not be construed as limiting the present invention. In addition to the above-described exemplary embodiments, additional embodiments may exist in the drawings and detailed description of the invention.

According to the above-described means for solving the problem of the present invention, an active matrix circuit for high-speed driving of a photodiode array that can be controlled using the same row-by-row control signal by making a first switch for reading the output of the photodiode and a second switch for providing a bias voltage to the photodiode operate complementarily with each other, and a driving method thereof can be provided.

According to the above-described means for solving the problem of the present invention, even when the first switch does not operate, the photodetector is biased by the second switch, so that a separate charging time for the photodetector is not required, and accordingly, after the corresponding photodetector is selected, an output signal is immediately generated, thereby providing an active matrix circuit for high-speed operation of a photodetector diode array capable of high-speed operation, and a driving method thereof.

According to the solution to the above-described problem of the present invention, there is an advantage that it can be used in various devices and fields requiring high-speed operation, such as flexible image sensors and flexible optical communication receivers.

However, the effects that can be obtained from this invention are not limited to the effects described above, and other effects may exist.

Figure 1 is a diagram showing a conventional active matrix structure.
Figure 2 is a graph comparing the current-voltage characteristics of a silicon type photodiode and an organic photodiode.
FIG. 3 is a schematic diagram of an active matrix circuit for high-speed driving of a photodiode array according to one embodiment of the present invention.
FIG. 4 is a schematic circuit diagram of a photodiode array capable of high-speed operation according to one embodiment of the present invention.
Figure 5a is a conceptual diagram showing signal transmission when a specific photodiode of a column is selected by a row-by-row control signal in a conventional active matrix structure.
FIG. 5b is a conceptual diagram showing signal transmission when a specific photodiode of a column is selected by a row-by-row control signal in an active matrix circuit for high-speed driving of a photodiode array according to one embodiment of the present invention.
FIG. 6 is a flowchart illustrating an operation method for driving a photodiode array capable of high-speed operation according to one embodiment of the present invention.

Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those with ordinary skill in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are assigned similar drawing reference numerals throughout the specification.

Throughout this specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected," but also the case where it is "electrically connected" or "indirectly connected" with another element in between.

Throughout this specification, when it is said that an element is located “on,” “above,” “below,” “below,” or “below” another element, this includes not only cases where an element is in contact with another element, but also cases where another element exists between the two elements.

Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

The present invention relates to an active matrix circuit for high-speed driving of a photodiode array and a driving method thereof. For example, the present invention relates to a photodiode array capable of high-speed driving and an active matrix circuit structure including the same.

FIG. 3 is a schematic diagram of an active matrix circuit for high-speed driving of a photodiode array according to one embodiment of the present invention.

Referring to FIG. 3, an active matrix circuit (10) for high-speed driving of a photodiode array according to an embodiment of the present invention (hereinafter, referred to as an 'active matrix circuit (10)') may include a photodiode array (100) capable of high-speed driving according to an embodiment of the present invention (hereinafter, referred to as a 'photodiode array (100)'), a control module (200), a bias module (300), and a readout module (400). Meanwhile, in the description of the embodiment of the present invention, each of the photodiode arrays (100) included in the active matrix circuit (10) may be arranged to form a matrix by forming a plurality of rows and a plurality of columns, and may thus be referred to differently as an 'array cell (100)'. In other words, in the description of the embodiment of the present invention, the reference numeral 100 may be used interchangeably for the photodiode array (100) and the array cell (100).

According to one embodiment of the present invention, each of the photodetector diode arrays (100), the control module (200), the bias module (300), and the reading module (400) provided in the active matrix circuit (10) can communicate with each other through a network (not shown). The network (20) means a wired and wireless connection structure capable of exchanging information between each node, such as terminals and servers, and examples of such a network (not shown) include, but are not limited to, a 3GPP (3rd Generation Partnership Project) network, an LTE (Long Term Evolution) network, a 5G network, a WIMAX (World Interoperability for Microwave Access) network, the Internet, a LAN (Local Area Network), a Wireless LAN (Wireless Local Area Network), a WAN (Wide Area Network), a PAN (Personal Area Network), a wifi network, a Bluetooth network, a satellite broadcasting network, an analog broadcasting network, a DMB (Digital Multimedia Broadcasting) network, etc.

FIG. 4 is a schematic circuit diagram of a photodiode array capable of high-speed operation according to one embodiment of the present invention.

Referring to FIG. 4, each of the plurality of array cells (100) forming the active matrix circuit (10) may include a photodetector diode (110), a first switch (120), and a second switch (130).

The photodiode (110) may be a device that generates a photocurrent corresponding to incident light. The photodiode may be a photoelectric conversion device or photodetector that can convert light energy into current or voltage as a photodiode.

Meanwhile, in the description of the embodiment of the present invention, the photodiode (110) may be an organic photodiode. The organic photodiode is a photodiode using organic materials, has a structure similar to that of a conventional solar cell, and has the characteristic that electrons and holes are formed by incident light and converted into electric signals through the photoelectric effect.

The development of organic-based photodiodes began using materials that can detect light in the visible light range. Although organic semiconductor materials have a large energy band gap and thus low external quantum efficiency, they have advantages such as the ability to detect light in a specific wavelength range and large-scale development, so research and development is underway to apply them to various fields of application.

Additionally, the first switch (120) may be a switching element for connecting the output signal of the photodiode (110) to the signal reading line based on a control signal applied by the control module (200).

Additionally, the second switch (130) may be a switching element for applying a preset bias voltage to the photodiode (110) based on a control signal applied by the control module (200).

Meanwhile, in the description of the embodiment of the present invention, the first switch (120) and the second switch (130) may operate complementarily based on a control signal applied from the control module (200). More specifically, the control signal applied from the control module (200) may include a first control signal for turning on the first switch (120) and turning off the second switch (130), and conversely, a second control signal for turning on the second switch (130) and turning off the first switch (120), and the first control signal or the second control signal may be applied to each of a plurality of rows formed by a plurality of array cells (100) on a row-by-row basis.

That is, when the first switch (120) is turned on according to the control signal, the second switch (130) is turned off, and accordingly, the output signal of the photodiode (110) can be transmitted to the reading module (400) through the signal reading line (41). More specifically, when the first switch (120) of one of the plurality of array cells (100) is turned on according to a control signal applied in units of rows, the second switch (130) of the corresponding array cell (100) is turned off, and the output signal of the photodetector diode (110) of the corresponding array cell (100) and the output signals of the array cells included in the row to which the corresponding array cell (100) belongs can be transmitted to the reading module (400) through the signal reading line (41) corresponding to each array cell (100) (in other words, the signal reading line (41) connecting the array cells included in the column to which the corresponding array cell (100) belongs, etc.).

In addition, according to one embodiment of the present invention, when the second switch (130) is turned on according to the control signal, the first switch (120) is turned off, and the cathode voltage of the photodetector diode (110) can be charged based on the bias voltage. Accordingly, when the first switch (120) is turned on again according to the control signal, a reverse bias that can generate a photocurrent can be formed in the photodetector diode (110), so that after the corresponding photodetector diode (110) is selected, an output signal can be generated immediately, enabling high-speed operation.

More specifically, according to one embodiment of the present invention, when the second switch (130) of one of the plurality of array cells (100) is turned on according to a control signal applied in units of rows, the first switch (120) of the corresponding array cell (100) is turned off, and the cathode voltage of the photodiode (110) of the corresponding array cell (100) and the array cells included in the row to which the corresponding array cell (100) belongs may be charged based on the bias voltage provided from the bias module (300) through each bias line (31).

In addition, the control module (200) may be a module for applying a control signal to each of the plurality of rows formed by the plurality of array cells (100) of the active matrix circuit (10). The control module (200) may be connected (connected) to the gates of the first switch (120) and the second switch (130) of the array cells (100) included in each of the plurality of rows of the active matrix circuit (10) through a control signal line (21).

In addition, the bias module (300) may be a module for applying a bias voltage corresponding to each of a plurality of columns formed by a plurality of array cells (100) of the active matrix circuit (10). The bias module (300) may be connected to the second switch (130) of the array cell (100) included in each of the plurality of columns of the active matrix circuit (10) through a bias line (31).

In addition, the reading module (400) may be a module for obtaining an output signal from each of a plurality of columns formed by a plurality of array cells (100) of the active matrix circuit (10). The reading module (400) may be connected to the first switch (120) of the array cell (100) included in each of the plurality of columns of the active matrix circuit (10) through a signal reading line (41).

Meanwhile, according to one embodiment of the present invention, the first switch (120) may be a P-type transistor (e.g., a PMOS device, etc.) and the second switch (130) may be an N-type transistor (e.g., an NMOS device, etc.). In addition, the first switch (120) may be one of an N-type transistor and a P-type transistor, and the second switch (130) may be the other of the N-type transistor and the P-type transistor.

More specifically, referring to FIG. 4, the first switch (120) may be arranged such that the gate terminal is connected to the control signal line (21) to which the control signal is applied, one of the source terminal and the drain terminal is connected to the signal reading line (41) of the corresponding array cell (100), and the other of the source terminal and the drain terminal is connected to the cathode terminal of the photodetector diode (110).

In addition, referring to FIG. 4, the second switch (130) may be arranged such that the gate terminal is connected to the control signal line (21) to which the control signal is applied, one of the source terminal and the drain terminal is connected to the bias line (31) of the corresponding array cell (100), and the other of the source terminal and the drain terminal is connected to the cathode terminal of the photodetector diode (110).

For reference, the photodiode array (100) illustrated in FIG. 4 is illustrated with the first switch (120) and the signal reading line (41) arranged relatively to the right, and the second switch (130) and the bias line (31) arranged relatively to the left, but it is obvious that this relative arrangement relationship may be applied differently depending on the implementation example of the present invention.

Hereinafter, with reference to FIGS. 5a and 5b, the circuit signal transmission mechanism of the conventional active matrix structure and the active matrix circuit (10) disclosed in the present invention will be compared with each other.

FIG. 5a is a conceptual diagram illustrating signal transmission when a specific photodetector of a column is selected by a row-by-row control signal in a conventional active matrix structure, and FIG. 5b is a conceptual diagram illustrating signal transmission when a specific photodetector of a column is selected by a row-by-row control signal in an active matrix circuit for high-speed driving of a photodetector diode array according to one embodiment of the present invention.

First, referring to FIG. 5a, in the case of a conventional active matrix structure, since the photodiode generates a photocurrent linearly proportional to the incident light when a reverse bias of a predetermined size or greater is applied, in a column-by-column reader (Col Readout of FIG. 5a), the column-by-column signal line (CR) is biased to a specific voltage (V _CR ). At this time, the longer the signal line, the longer it takes to charge the cathode voltage (V _PD ) of the photodiode by the RC value of the signal line. This problem can be more severe when an organic photodiode, which has the characteristic of not generating a sufficiently large photocurrent at a low reverse bias, is used.

In contrast, referring to FIG. 5b, in the case of the active matrix circuit (10) disclosed in the present invention, even when the first switch (120) is not operating, the photodetector diode (110) can be biased by the second switch (130) (complementary operation of the first switch and the second switch), so that the charging time of the photodetector diode as in the conventional active matrix structure is not required.

Therefore, even when using an organic photodiode, the photodiode (110) has the advantage of generating an output signal immediately without a separate bias charging time when it is selected by a control signal, thereby enabling high-speed operation of the active matrix.

Based on these characteristics that enable high-speed operation, an active matrix circuit (10) based on an organic photodiode has the advantage of being usable in various applications that require high-speed operation, such as a flexible image sensor and a flexible optical communication receiver.

Below, we will briefly review the operating flow of this system based on the detailed explanation above.

FIG. 6 is a flowchart illustrating an operation method for driving a photodiode array capable of high-speed operation according to one embodiment of the present invention.

The driving method of the light-receiving diode array capable of high-speed driving illustrated in Fig. 6 can be performed by the active matrix circuit (10) described above. Therefore, even if the content is omitted below, the content described for the active matrix circuit (10) can be equally applied to the description of the driving method of the light-receiving diode array capable of high-speed driving.

Referring to FIG. 6, in step S11, the control module (200) of the active matrix circuit (10) can turn on the second switch (130) of one of the plurality of array cells based on the control signal to charge the cathode voltage of the photodetector diode (110) of the corresponding array cell based on the bias voltage.

Next, in step S12, the control module (200) of the active matrix circuit (10) can turn on the first switch (120) of one of the plurality of array cells based on the control signal so that the output signal of the photodetector diode (110) of the corresponding array cell is transmitted to the reading module (400) through the signal reading line (41).

In the above description, steps S11 and S12 may be further divided into additional steps or combined into fewer steps, depending on the implementation example of the present invention. In addition, some steps may be omitted as needed, and the order between the steps may be changed.

A method for driving a photodiode array capable of high-speed operation according to one embodiment of the present invention may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program commands, data files, data structures, etc., alone or in combination. The program commands recorded on the medium may be those specially designed and configured for the present invention or may be those known to and usable by those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands such as ROMs, RAMs, and flash memories. Examples of the program commands include not only machine language codes generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc. The above hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

In addition, the driving method of the photodiode array capable of high-speed driving described above can also be implemented in the form of a computer program or application executed by a computer stored in a recording medium.

The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single component may be implemented in a distributed manner, and likewise, components described as distributed may be implemented in a combined manner.

The scope of the present application is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application.

10: Active matrix circuit for high-speed driving of photodiode array
100: High-speed drive capable photodiode array, array cell
110: Photodiode
120: 1st switch
130: 2nd switch
200: Control Module
21: Control signal line
300: Bias module
31: Bias Line
400: Reading module
41: Signal reading line

Claims (15)

In a photodiode array capable of high-speed operation,
A photodiode that generates a photocurrent corresponding to incident light;
A first switch connecting the output signal of the photodiode to a signal reading line based on a control signal; and
A second switch for applying a preset bias voltage to the photodiode based on the above control signal;
A diode array comprising: In the first paragraph,
The above first switch and the above second switch,
A diode array characterized by operating complementarily based on the above control signal. In the second paragraph,
A diode array, wherein when the first switch is turned on according to the control signal, the second switch is turned off, and the output signal is transmitted to the reading module through the signal reading line. In the second paragraph,
A diode array in which, when the second switch is turned on according to the control signal, the first switch is turned off, and the cathode voltage of the photodetector is charged based on the bias voltage. In paragraph 4,
A diode array, wherein when the first switch is turned on according to the control signal, a reverse bias is formed in the photodetector diode so that the photocurrent can be generated. In the second paragraph,
A diode array, characterized in that the first switch is one of an N-type transistor and a P-type transistor, and the second switch is the other of the N-type transistor and the P-type transistor. In the first paragraph,
A diode array, wherein the above photodetector diode is an organic photodetector diode. In an active matrix circuit for high-speed driving of a photodiode array,
A plurality of array cells each having a photodiode generating a photocurrent corresponding to incident light, a first switch connecting an output signal of the photodiode to a signal readout line based on a control signal, and a second switch applying a preset bias voltage to the photodiode based on the control signal, the plurality of array cells being arranged to form a matrix in a plurality of rows and a plurality of columns;
A control module for applying the control signal to each of the plurality of rows of the plurality of array cells;
A bias module for applying the bias voltage corresponding to each of the plurality of columns of the plurality of array cells; and
A read module for obtaining the output signal from each of the plurality of columns of the plurality of array cells;
An active matrix circuit comprising: In Article 8,
The above bias module is connected to the second switch and the bias line of the array cell included in each of the plurality of columns,
An active matrix circuit, wherein the reading module is connected to the first switch and signal reading line of the array cells included in each of the plurality of columns. In Article 8,
The first switch and the second switch provided for each of the plurality of array cells are,
An active matrix circuit characterized by operating complementarily based on the above control signal. In Article 10,
An active matrix circuit, wherein when the first switch of one of the plurality of array cells is turned on according to the control signal, the second switch of the one of the array cells is turned off, and the output signal is transmitted to the read module through the signal read line corresponding to the one of the array cells. In Article 10,
An active matrix circuit, wherein when the second switch of one of the plurality of array cells is turned on in accordance with the control signal, the first switch of the one of the array cells is turned off, and the cathode voltage of the photodetector of the one of the array cells is charged based on the bias voltage. In Article 12,
An active matrix circuit, wherein when the first switch of one of the array cells is turned on according to the control signal, a reverse bias is formed in the photodetector diode of one of the array cells so that the photocurrent can be generated. In Article 8,
An active matrix circuit, wherein the photodetector diode is an organic photodetector diode. A method for driving a photodiode array capable of high-speed operation according to Article 1,
A step of turning on the second switch based on the control signal to charge the cathode voltage of the photodetector diode based on the bias voltage; and
A step of turning on the first switch based on the control signal and transmitting the output signal of the photodetector through the signal reading line;
A driving method comprising:

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