JP2017076797A - Image sensor having function of solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which a solar cell with an optical detector shares the same cell with a pixel of an image sensor, and each cell is selected, as needed, as an image sensor or as a solar cell that produces and stores a drive power.SOLUTION: A unit pixel element that can operate as an image sensor and a solar cell includes: a photodetector that generates an optical current on a channel between a source and a drain by light received at its gate; a first switch coupled between the source terminal of the photodetector and a first solar cell bus to perform an on/off operation; and a second switch coupled between the gate terminal of the photodetector and a second solar cell bus to perform an on/off operation. Simultaneously with performing a function as the image sensor, optical energy harvesting becomes possible, and thereby, an effective power can be generated and supplied with a high-efficiency photoelectric conversion capability.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image sensor that can operate as a solar cell, and more particularly to a technique that generally functions as an image sensor and operates as a solar cell through mode switching to specific conditions as necessary.

Optical energy harvesting technology is always necessary for the infrastructure of things (Internet of Things), ubiquitous sensor network, and wireless sensor network (Wireless Sensor Network). It is a technology that can be used as a semi-permanent power source in various electronic devices and can convert light energy into electrical energy and charge without providing wired power to an existing battery.

On the other hand, it is desirable to implement such a system in an ultra-small and integrated form. In some researches, light energy conversion elements are fabricated in the form of ISC (Integrated Solar Cell) using PN junction photodiodes in a CMOS process, and integration with other circuits is attempted. In some cases, such a photodiode has low efficiency in photoelectric conversion capability, and it is difficult to supply sufficient power for the operation of the circuit in the chip. There is still a limit to the complete integration of the solar cell process and the standard CMOS process.

The present invention is not limited to the already registered patent “Unit Pixel of Image Sensor and Photo Detector Ther of” (Patent Document 1, Patent Document 2, Patent Document 3), and is a pixelated solar cell system on. It is intended to present a method and concept for implementing a chip. First, the structure and operation principle of a photodetector and pixel-shaped solar cell manufactured through a standard CMOS process will be described, and the solar cell manufactured in this way and the pixel of the image sensor are required to share the same cell. We propose a method that can be selected and used according to each.

US Pat. No. 8,569,806 U.S. Pat. No. 8610234 US Pat. No. 8,669,599

In order to solve the problems of the prior art as described above, the solar cell having a high-efficiency photodetector shares the same cell as the pixel of the image sensor, and selects each as necessary. It is an object of the present invention to provide a method that can be used as an image sensor or as a solar cell that produces and stores drive power.

In order to achieve the above object, a unit pixel element operable as an image sensor and a solar cell includes a photodetector that generates a photocurrent in a channel between a source and a drain by light received by a gate, and a source terminal of the photodetector And a first switch connected between the first solar cell buses to perform an on / off operation, and a second switch connected between the gate terminal of the photodetector and the second solar cell bus to perform an on / off operation.

A unit pixel element operable as an image sensor and a solar cell for achieving the object includes a photodetector for generating a photocurrent in a channel between a source and a drain by light received by a gate, a gate terminal of the photodetector, and A first switch configured to perform an on / off operation between the first solar cell buses, and a selection element connected between a source terminal of the photodetector and the second solar cell bus and outputting the photocurrent to a pixel output terminal.

  A unit pixel element operable as an image sensor and a solar cell for achieving the above object includes a photodetector that generates a photocurrent in a channel between a source and a drain by light received by a gate, and a gate terminal of the photodetector And a first switch connected between the first solar cell buses for on / off operation, a second switch connected between the reset terminal of the photodetector and the first solar cell bus for on / off operations, and the photo A selection element is connected between the source terminal of the detector and the second solar cell bus and outputs the photocurrent to a pixel output terminal.

  According to the embodiment of the present invention, it can function as an image sensor and at the same time can harvest light energy, and can generate and supply effective power with high efficiency photoelectric conversion capability.

In addition, according to the preferred embodiment of the present invention, in the manufacturing process, it can be manufactured in a completely integrated form with the peripheral circuit, and it is highly integrated with not only the image sensor but also any peripheral circuit manufactured by the CMOS process. Easy to.

It is sectional drawing which shows the photodetector in which the highly efficient photoelectric conversion which concerns on this invention is possible. It is a figure which shows the highly efficient photoelectric conversion mechanism of the said photodetector based on this invention. It is sectional drawing which shows the photodetector for the solar cell which concerns on this invention. It is a figure which shows the electric power generation mechanism of the said photodetector which concerns on this invention. FIG. 3 is a diagram illustrating an open circuit voltage (VOC) acquisition mechanism of the photodetector according to the first embodiment of the present invention. It is sectional drawing which shows the open circuit voltage acquisition mechanism of the said photodetector based on 2nd Example of this invention. It is a figure which shows the structure of the unit pixel of the solar cell which concerns on this invention. It is a figure which shows the structure of the unit pixel of the image sensor which concerns on 1st Example of this invention. It is a figure which shows the structure of the unit pixel of the solar cell which concerns on 1st Example of this invention. It is a figure which shows the 2nd unit pixel of the image sensor which concerns on 2nd Example of this invention. It is a figure which shows the 2nd unit pixel structure of the solar cell which concerns on 2nd Example of this invention.

Since the invention is susceptible to various modifications and may have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the Detailed Description. However, this should not be construed as limiting the invention to the specific embodiments, but should be understood to include any modifications, equivalents or alternatives that fall within the spirit and scope of the invention.

In the description of the present invention, when it is determined that there is a possibility that a specific description of a related known technique may unnecessarily disturb the gist of the present invention, a detailed description thereof will be omitted. Further, the numbers (for example, first, second, etc.) used in the description process of this specification are merely identification symbols for distinguishing one component from other components.

Further, in this specification, when one component is referred to as “coupled” or “connected” to a different component, the one component is directly coupled to the other component. It is to be understood that they may be connected or connected directly, but unless stated to the contrary, they may be linked or connected via other components in between.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a photo detector capable of high efficiency photoelectric conversion according to the present invention.

In FIG. 1, a light receiving element of a unit pixel corresponding to the photodetector is implemented using a tunnel junction device instead of a conventional photodiode. Here, the tunnel junction element has a structure in which a thin insulating layer is bonded between two conductors or semiconductors, and refers to an element that operates using a tunneling effect generated in the insulating layer. Incidentally, the tunneling effect is a quantum mechanical phenomenon in which a particle moving under the action of a force having a potential passes through a region having a positional energy larger than that of the particle itself. Say.

In one embodiment of the present invention, a photo detector and a solar cell of a unit pixel can be generated using such a photo detector, and a “photo detector” used in the present specification and claims is referred to as “photo detector”. Denotes a light receiving element and a solar cell implemented using the tunnel junction element. The photodetector can be implemented by various types of structures, for example, using a general n-MOSFET or p-MOSFET structure. In addition to the MOSFET, the unit element can be implemented using an electronic element having a structure capable of obtaining a tunneling effect such as JFET or HEMT.

In FIG. 1, the photodetector 100 is implemented with a PMOS structure. The photodetector 100 is formed on a P-type substrate 110 and includes a P + diffusion layer 120 corresponding to a source and a P + diffusion layer 130 corresponding to a drain in a general NMOS electronic device. Hereinafter, the P + diffusion layers 120 and 130 are respectively referred to as “source” and “drain” in the photodetector.

A source electrode 121 and a drain electrode 131 connected to an external node are formed on the source 120 and the drain 130, respectively.

The photodetector 100 forms an N well 115 by injecting an N type impurity onto a P type substrate (P-sub) 110. A source 120 and a drain 130 are formed by implanting a high-concentration P-type impurity on the formed N well 115. A thin oxide film 140 is formed between the source 120 and the drain 130, and polysilicon (poly-) doped with an N-type impurity corresponding to a gate in a general MOSFET structure is formed on the oxide film 140. silicon) is formed. The polysilicon 150 functions as a part that absorbs light in the photodetector 100. Hereinafter, the polysilicon 150 is referred to as a “light receiving portion”.

The light receiving unit 150 is separated from the source 120 and the drain 130 by the oxide film 140. Tunneling is generated between the light receiving unit 150 and the source 120 or the drain 130. At this time, in order to facilitate the occurrence of the tunneling phenomenon, it is desirable to form the oxide film 140 with a thickness of 10 nm or less.

Unlike a gate of a general MOSFET element, the photo-detector 100 may be formed with a metallic light-shielding layer in the upper part of the remaining area except for the upper part of the light receiving part 150. The photodetector 100 maximizes the photoelectric conversion in the light receiving unit 150 by limiting the region where light is incident through the light shielding layer to the light receiving unit 150.

The structure of the photodetector 100 can be easily manufactured through a standard CMOS process, can be manufactured in the same process as other circuits, and can be used as a part of an integrated system. It is easy to integrate and has a wide range of applications.

FIG. 2 shows a highly efficient photoelectric conversion mechanism of the photodetector 100 according to the present invention. The photodetector 100 receives light through the upper part of the light receiving unit 150. Electron-hole pairs (EHP) are generated by the light incident on the light receiving unit 150, and a constant electric field is formed between the light receiving unit 150, the source 120, and the drain 130. At this time, when a constant voltage is applied to the source electrode 120 and the drain electrode 131, the charge of the light receiving unit 150 excited by light tunnels through the oxide film 140 from the light receiving unit 150 and moves to the source 120 or the drain 130. To do. As holes are lost in the light receiving unit 150 due to tunneling and electrons flow in, the amount of charge of electrons in the light receiving unit 150 relatively increases. When the threshold voltage of the channel 160 between the drains 130 is lowered, a photocurrent flows through the channel 160. Such techniques have already been filed and registered in the United States by the inventors of the present invention, such as US Patents US8,569,806B2, US8,610,234B2, US8,669,599B2 and US Patent Application US14 / 327,549. The detailed description will be omitted.

In the photodetector 100, the light incident area is limited only to the upper area of the light receiving section 150, and light of various wavelength bands is incident through the upper section of the light receiving section 150 opened from the outside. The incident light of various wavelength bands is absorbed by the light receiving unit 150 or transmitted through the light receiving unit 150 and reaches the lower N well 115 or the substrate 110. For example, when the thickness of the light receiving unit 150 is 150 nm or more, the blue series of short wavelengths cannot reach the lower substrate 110 and are mostly absorbed by the light receiving unit 150. Unlike conventional general photodetectors, the photodetector 100 according to the present invention has the energy absorbed in the light receiving unit 150 even if light in the short wavelength band cannot be reached by the lower substrate and is absorbed by the light receiving unit 150. Since a change is generated in the charge amount of the light receiving unit 150 and a current is generated in the channel 160, light in the short wavelength band can be easily detected. In addition, since all light in other wavelength bands is transmitted through the light receiving unit 150, a similar phenomenon occurs in the light receiving unit 150 and affects the change in the threshold voltage of the current channel.

On the other hand, the light having a relatively long wavelength band that can pass through the light receiving unit 150 generates an electron-hole pair in the N well 115, and as shown in FIG. Accumulation in the well 115 may affect the change in threshold voltage. The photodetector 100 manufactured as described above has a high-sensitivity detection capability capable of sensing a single photon, and also has a capability of allowing a very large photocurrent to flow even with a small amount of light. Such characteristics of the photodetector 100 of the present invention can be used not only as a photodetector for an image sensor but also as a solar cell.

Below, based on the principle of such a photodetector, the solar sensor chip of the system on chip (SOC: System On Chip) form newly added the function as a solar cell is proposed. Furthermore, although FIGS. 1 and 2 are described based on a PMOS type structure, the PMOS type structure can be embodied by an NMOS type structure and other similar structures. All structures are considered to be within the scope of the present invention.

FIG. 3 is a cross-sectional view of a photodetector for a solar cell according to the present invention, and FIG. 4 is a diagram illustrating a power generation mechanism of the photodetector 300. When the photodetector 300 operates as a solar cell, a photocurrent is generated by absorption of light and a photovoltaic voltage is generated.

Referring to FIG. 3, when the light is absorbed by the light receiving unit 350, the photo detector 300 tunnels the oxide film 140 from the channel between the source 120 and the drain 130 and moves to the light receiving unit 350. As a result, the total charge amount of the light receiving unit 350 is changed. At this time, if the voltage between the light receiving unit 350 and the drain 130 is measured, the amount of change in charge generated by light can be measured in the form of voltage. Further, the electric charge accumulated in the N well 115 can be measured by a voltage by the electrodes 131 and 361 between the drain 130 and the W-RST 360.

Referring to FIG. 4, when light energy larger than the threshold voltage of the transistor initially formed in the manufacturing process is incident on the photodetector 300, a photocurrent flows through the channel 160.

Specifically, between the source 120 and the drain 130, the potential state of the silicon interface where the channel 160 can be formed from the first manufacturing process has a threshold voltage just before the sub-threshold. Is formed. In this state, if no light is incident on the light receiving unit 350, no photocurrent flows through the channel 160.

In this state, when light having an energy larger than the energy of the doped impurities is incident on the light receiving portion 350, the light receiving portion 350 has a boundary between the oxide film 140 that blocks charge movement in an equilibrium state. Thus, a large number of electrons and holes formed by doping impurities are in a free state. At this time, the generated electron-hole pairs exist in a state of electrons and holes for a certain period of time until recombination, and the charge moves to a place where the electric field is concentrated locally. become.

Since the potential of the silicon interface between the source 120 and the drain 130 is in a state immediately before the sub-threshold, the source 120 and the drain 130 are received by the charge amount and the electric field increased by the light incident on the light receiving unit 350. Electrons or holes are tunneled between the portion 350 and the threshold voltage of the channel 160 is lowered, and a photocurrent flows through the channel 160 in proportion to the amount of light.

The voltage generating the photocurrent can be detected through the light receiving unit 350 or the N well 115. The detected voltage varies depending on the amount of light detected through the light receiving unit 350 or the N-well 115, but a photocurrent of several nanometers to several microamperes may flow. It can be about 0.1 to 1.0V. Incidentally, the value is a measurement value excluding dark current, and such output is obtained from a pixel size within 3 μm. Therefore, if a plurality of pixels are connected in series or in parallel to form a pixel array and controlled, a very large power can be obtained.

FIG. 5 illustrates a mechanism for obtaining an open circuit voltage (Voc) of the photodetector 300 according to the first embodiment of the present invention.

Referring to FIG. 5, when light is incident on the light receiving unit 350 with a constant voltage applied between the source 120 and the drain 130, the threshold voltage changes and a photocurrent flows. The light in the long wavelength band passes through the light receiving unit 350 and is absorbed by the N well 115. At this time, a constant amount of charge is generated in the N well 115 by the same principle as that of the light receiving unit 150, and around the channel interface. Will be accumulated.

At this time, the photocurrent flowing in the channel is caused by a voltage generated by changing the charge amount in the light receiving unit 350 and the N well 115. That is, the generated photocurrent generates a voltage (V _Drain-Gate ) between the drain 130 and the light receiving unit 350 and a voltage (V _Drain-Wrst ) between the drain 350 and the N well 115. Therefore, the voltage (V _Drain-Gate ) between the terminal 131 connected to the drain 130 and the terminal 351 connected to the light receiving unit 350 or the terminal 131 connected to the drain 350 and the N well 115 is connected. Voc can be obtained by selecting any one of the voltages (V _Drain−Wrst ) between the terminals 361.

FIG. 6 illustrates an open circuit voltage acquisition mechanism of the photodetector 300 according to the second embodiment of the present invention.

In order to obtain a desired large electric power, it is necessary to obtain a larger Voc value in addition to a method of obtaining a large photocurrent from the photodetector 300. In FIG. 6, when the terminal 351 connected to the light receiving unit 350 and the terminal 361 connected to the N + diffusion layer 360 formed on the N well 115 are connected, the change in the threshold voltage of the channel is further increased. A larger voltage (V _{Drain− (gate−wrst)} ) can be obtained between the terminal 352 connected to the light receiving unit 350 and the N well 115 and the terminal 132 connected to the drain 130. This is an effect due to the amount of charge additionally increased by electrons existing under the N well 115 moving to the N + diffusion layer 360.

FIG. 7 shows the structure of a unit pixel of a solar cell according to the present invention. Referring to FIG. 7, the solar cell has a unit pixel 700 structure configured as a pixel solar cell.

The unit pixel 700 includes the photodetector 300, a first switch (Ms), a second switch (Mg), a third switch (Mwr), a fourth switch (Mv), a first solar cell bus (SCB1), and a second solar. Includes cell bus (SCB 2). The photodetector 300 generates a photocurrent in the channel between the source and the drain by the light (hv) received by the light receiving unit (gate). The first switch Ms is connected between the source terminal of the photodetector 300 and the first solar cell bus SCB1 to perform an on / off operation. The second switch (Mg) is connected between the light receiving unit (gate) terminal of the photodetector 300 and the second solar cell bus (SCB 2) to perform an on / off operation. The third switch (Mwr) is connected between the reset terminal connected to the N well or the substrate of the photodetector 300 and the second solar cell bus to perform an on / off operation. Here, the reset terminal is doped with an impurity different from the impurity doped in the source and the drain. 3 to 6, the reset terminal (Wrst) is doped with an N-type impurity different from the P-type impurity doped in the source and the drain. In the case of NMOS, the reset terminal is connected to the source. In addition, the drain may be doped with a P-type impurity different from the N-type impurity doped. Here, in order to drive the photodetector 300, VDD is connected and fixed to a power supply of a separate external system. At this time, the VDD may be connected to the drain of the photodetector 300 through a fourth switch (Mv). At this time, a circuit for removing the dark current separately from the pixel by applying the minimum VDD voltage so that the minimum dark current flows may be added.

Meanwhile, since the photo detector 300 is manufactured in the same process as the peripheral circuit, the same power source as the peripheral circuit can be used. In this case, unlike the conventional photodetector, the photodetector 300 of the present invention can be configured to use the power supply of the peripheral circuit as it is without requiring a separate external power supply.

When light is incident on the photodetector 300, a photocurrent flows between the first solar cell bus (SCB 1) and the second solar cell bus (SCB 2). At the same time, the second switch (Mg) By controlling the third switch (Mwr), the photovoltaic power Voc can be obtained between the first solar cell bus (SCB 1) and the second solar cell bus (SCB 2).

The second switch (Mg) and the third switch (Mwr) may be selectively connected to an external matrix such as a row decoder by a switch-on operation. At this time, the second switch (Mg) and the third switch (Mwr) are separately switched on and connected to the second solar cell bus (SCB 2), or are switched on at the same time and switched to the second solar cell bus. It is possible to select whether to be connected to (SCB 2). When the second switch (Mg) and the third switch (Mwr) are simultaneously switched on and connected to an external matrix, as shown in FIG. 6, the light receiving unit and the N well of the photodetector 300 are connected. A larger Voc can be obtained than when separately connected to the second solar cell bus (SCB 2).

FIG. 8 shows a unit pixel structure of the image sensor according to the first embodiment of the present invention. The unit pixel 1000 includes a selection element (SEL) connected to the photodetector 300, and the unit pixel 1000 includes an image sensor and a column bus formed of an IVC circuit 1010 that is a current-voltage conversion circuit. It is good to be connected by. Here, the selection element (SEL) may be realized by various elements, and may be formed using a MOSFET structure, for example. In this case, since the photodetector 300 and the selection element (SEL) can be simultaneously implemented using a MOSFET manufacturing process, it can be manufactured easily and at low cost.

The photoelectric current photoelectrically converted by the photodetector 300 of the unit pixel 1000 is charged in the capacitor 1015 of the IVC circuit 1010 when the SEL is switched on. The photocurrent charged in the capacitor 1015 is output as a voltage having an IVC_OUT value, and a signal is transmitted to a circuit such as CDS (Co-Double Sampling). If BUS_RST is turned on while the SEL is on, the capacitor 1015 and the column bus (CB) of the IVC circuit 1010 and the photodetector 300 are directly connected to each other through the GND. The signal is reset after being removed. With the above operation, it is possible to define the integration time required for the image sensor and acquire a continuous image.

FIG. 9 illustrates a unit pixel structure for the solar cell according to the first embodiment of the present invention. As the unit pixel 1100, the unit pixel 1000 of the 1T type image sensor shown in FIG. 8 is implemented as a solar cell. For this, the unit pixel 1100 can use the image sensor in FIG. 8 as a solar cell by adding first and second solar cell buses (SCB 1, SCB 2) and S1, S2 switches. .

Specifically, the unit pixel 1100 includes the photodetector 300 that generates a photocurrent in a channel between a source and a drain by light received by a gate, the gate terminal of the photodetector 300, and the first solar cell bus (SCB1). A first switch (S1) connected between the photo detector 300 and a source terminal of the photodetector 300 and the second solar cell bus (SCB 2) to connect the photocurrent to the pixel output terminal 1010; A selection element (SEL) to be output is included. Here, the pixel output terminal 1010 corresponds to the IVC circuit 1010 in FIGS. In addition, the unit pixel 1100 may further include a second switch S2 connected between the selection element SEL and the pixel output terminal 1010 to perform an on / off operation. The first solar cell bus (SCB1) is connected to the gate of the photodetector 300 through the first switch (S1), and the column bus (CB) in FIG. 8 is connected to the first switch through the second switch (S2). When used as a two solar cell bus (SCB 2), a photocurrent and Voc can be obtained between the first and second solar cell buses (SCB 1, SCB 2) to generate electric power. In this manner, the image sensor and the solar cell can be selectively implemented using the first and second switches (S1, S2). That is, if the first switch (S1) is on and the selection element (SEL) or the second switch (S2) is off, the unit pixel 1100 is cut off from the signal processing circuit at the subsequent stage and operates as a solar cell. If the S1 switch (S1) is off and the second switch (S2) is on, the unit pixel 1100 is connected to a subsequent signal processing circuit and operates as an image sensor.

In addition, the pixel output terminal 1010 is connected between the second solar cell bus (SCB 2) and the ground (GND) and charged by the photocurrent, the second solar cell bus (SCB 2), and the A reset element (BUS_RST) is connected between the ground (GND) and connected in parallel with the capacitor 1015.

FIG. 10 shows a second unit pixel of the image sensor according to the second embodiment of the present invention. As shown in FIG. 8, the second unit pixel 1200 includes a reset element (RST) connected to a well of the photodetector 300 in addition to the photodetector 300 and the selection element (SEL). Further included. An image sensor can be implemented by connecting the IVC circuit 1010 to each column of unit pixels such as the second unit pixel 1200. When the selection element (SEL) is on, the photoelectric current photoelectrically converted by the photodetector 300 charges the capacitor 1015 of the IVC circuit 1010 with a photoelectric charge. The photoelectric charge charged in the capacitor 1015 is output as a voltage having an IVC_OUT value, and the signal is transmitted to a circuit such as a CDS.

When BUS_ST is turned on while the selection element (SEL) is on, the capacitor 1015 and the column bus (CB) of the IVC circuit 1010 and the photodetector 300 are directly connected via GND, so that they are charged. The charge is removed and the signal is reset.

Meanwhile, the reset element (RST) may be used to smoothly reset the signal by the photodetector 300 or to manually adjust the threshold voltage of the current channel. In operation, it may be used at the time of special shooting without a video delay phenomenon or the like.

FIG. 11 illustrates a second unit pixel structure of a solar cell according to a second embodiment of the present invention.

The second unit pixel 1300 is obtained by implementing the unit pixel 1200 of the 2T type image sensor shown in FIG. 10 as a solar cell. The second unit pixel 1300 is connected between a photodetector 300 that generates a photocurrent in a channel between a source and a drain by light received by a gate, and a gate terminal of the photodetector 300 and a first solar cell bus (SCB1). A first switch (S1) for performing an on / off operation, and a second switch (S2) for performing an on / off operation connected between a reset terminal of the photodetector 300 and the first solar cell bus (SCB1). In addition to a selection element (SEL) connected between a source terminal of the photodetector 300 and a second solar cell bus (SCB 2) to output the photocurrent to the pixel output terminal 1010, a well (well) of the photodetector 300 is provided. And a reset element (RST) coupled toHere, the reset terminal (RST) is doped with an impurity different from the impurity doped in the source and the drain.

In addition, the second unit pixel 1300 may further include a third switch S3 connected between the selection element SEL and the pixel output terminal 1010 to perform an on / off operation. Here, when the first switch (S1) or the second switch (S2) is on and the third switch (S3) is off, the unit pixel operates as a solar cell, When the switch (S1) and the second switch (S2) are off and the third switch (S3) is on, the unit pixel operates as an image sensor. Here, in order to obtain a larger Voc, the first switch (S1) and the second switch (S2) may be simultaneously turned on.

The pixel output terminal 1010 includes a capacitor 1015 connected between the second solar cell bus (SCB 2) and the ground (GND) for charging by the photocurrent, the second solar cell bus (SCB 2), and the ground ( GND) and a reset element (BUS_RST) connected in parallel with the capacitor 1015. With such a configuration, electric current and Voc can be acquired between the first and second solar cell bus (SCB 1 and SCB 2) lines to generate electric power.

The above description of the present invention is given for the purpose of illustration, and those having ordinary knowledge in the technical field to which the present invention pertains will not be able to change the technical idea or essential features of the present invention. It will be understood that various modifications can be easily made.

Thus, it should be understood that the embodiments described above are illustrative in all aspects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, each component described as being distributed may be combined and implemented.

The scope of the present invention is defined by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are within the scope of the present invention. Should be interpreted as included.

Claims (16)

In unit pixel elements that can operate as image sensors and solar cells,
A photodetector that generates photocurrent in the channel between the source and drain by the light received by the gate;
A first switch connected between a source terminal of the photodetector and a first solar cell bus to perform an on / off operation; and
A unit pixel element including a second switch connected between a gate terminal of the photodetector and a second solar cell bus to perform an on / off operation. The unit pixel element of claim 1, further comprising a third switch connected between a reset terminal of the photodetector and the second solar cell bus. The unit pixel element according to claim 1, wherein the reset terminal is doped with an impurity different from an impurity doped in the source and the drain. In unit pixel elements that can operate as image sensors and solar cells,
A photodetector that generates photocurrent in the channel between the source and drain by the light received by the gate;
A first switch connected between the gate terminal of the photodetector and the first solar cell bus to perform an on / off operation; and
A unit pixel element including a selection element connected between a source terminal of the photodetector and a second solar cell bus to output the photocurrent to a pixel output terminal. The unit pixel element according to claim 4, further comprising a second switch connected between the selection element and the pixel output terminal to perform an on / off operation. The unit pixel element according to claim 5, wherein the unit pixel operates as a solar cell when the first switch is on and the selection element or the second switch is off. The unit pixel element according to claim 5, wherein the unit pixel operates as an image sensor when the first switch is off and the second switch is on. 5. The unit pixel element according to claim 4, wherein the pixel output terminal includes a capacitor that is connected between the second solar cell bus and the ground and performs charging by the photocurrent. 6. 9. The unit pixel element according to claim 8, wherein the pixel output terminal further includes a reset element connected between the second solar cell bus and the ground and connected in parallel with the capacitor. In unit pixel elements that can operate as image sensors and solar cells,
A photodetector that generates photocurrent in the channel between the source and drain by the light received by the gate;
A first switch connected between the gate terminal of the photodetector and the first solar cell bus to perform an on / off operation;
A second switch connected between a reset terminal of the photodetector and the first solar cell bus and performing an on / off operation; and a source switch of the photodetector and a second solar cell bus; A unit pixel element including a selection element to be output to the pixel output terminal. The unit pixel element according to claim 10, wherein the reset terminal is doped with an impurity different from an impurity doped in the source and the drain. The unit pixel element of claim 10, further comprising a third switch connected between the selection element and the pixel output terminal to perform an on / off operation. The unit pixel element according to claim 10, wherein the unit pixel operates as a solar cell when the first switch or the second switch is on and the third switch is off. The unit pixel element according to claim 10, wherein when the first switch and the second switch are off and the third switch is on, the unit pixel operates as an image sensor. 11. The unit pixel element according to claim 10, wherein the pixel output terminal includes a capacitor that is connected between the second solar cell bus and the ground and performs charging by the photocurrent. The unit pixel element according to claim 15, wherein the pixel output terminal further includes a reset element connected between the second solar cell bus and a ground unit and connected in parallel with the capacitor.