KR20190089701A - Image sensor - Google Patents

Abstract

An image sensor according to an embodiment of the present invention comprises: a first photodiode connected to a first floating diffusion through a first transmission transistor; a second photodiode included in the same pixel as the first photodiode and connected to a second floating diffusion through a second transmission transistor and a switch element; a pixel circuit having a first reset transistor connected between a power node and the second floating diffusion, and a second reset transistor connected between the first floating diffusion and the second floating diffusion; and a controller for detecting a first pixel voltage corresponding to charges of the first floating diffusion by turning off the second reset transistor for a first time, and detecting a second pixel voltage corresponding to charges of the first floating diffusion and the second floating diffusion by turning on the second reset transistor when a second time after the first time starts.

Description

Image sensor {IMAGE SENSOR}

The present invention relates to an image sensor.

An image sensor is a semiconductor-based sensor that accepts light to produce an electrical signal, which may include a pixel array having a plurality of pixels, a circuit for driving the pixel array and generating an image, and so on. The plurality of pixels may include a photodiode that generates charges in response to external light, and a pixel circuit that converts charge generated by the photodiode into an electric signal. Image sensors can be widely applied to smart phones, tablet PCs, laptop computers, televisions, automobiles, and the like, in addition to cameras for taking pictures and moving images. Recently, in order to improve the dynamic range of an image sensor, studies have been actively conducted to accurately detect light of a light source in which a flicker phenomenon occurs.

One of the problems to be solved by the technical idea of the present invention is to provide a liquid crystal display device having a wide dynamic range and capable of accurately detecting light of an external light source such as a semiconductor light emitting device And to provide an image sensor.

An image sensor according to an embodiment of the present invention includes a first photodiode for generating and storing a charge in a first floating diffusion, a second photodiode included in a pixel such as the first photodiode, a first floating diffusion, And a pixel circuit having a first floating diffusion and a second floating diffusion, and after accumulating charge accumulated in the first floating diffusion to the second floating diffusion to detect a first pixel voltage, the second floating diffusion is reset to detect a reset voltage And a controller for moving the charge generated in the second photodiode to the second floating diffusion to detect the second pixel voltage.

The image sensor according to an embodiment of the present invention includes a first photodiode, a second photodiode included in a pixel such as the first photodiode, a first photodiode connected to the first photodiode through a first transfer transistor, A pixel circuit having a first floating diffusion, a second floating diffusion coupled to the first floating diffusion through a first reset transistor, and an overflow transistor coupled between the first photodiode and a power node, One transfer transistor is alternately turned on and off multiple times to store the charge generated by the first photodiode in the first floating diffusion and the second floating diffusion is reset to detect the first reset voltage A controller for turning on the first reset transistor to detect a first pixel voltage from the second floating diffusion .

According to an embodiment of the present invention, there is provided an image sensor including: a first photodiode; a second photodiode included in a pixel such as the first photodiode; A second floating diffusion that receives charge generated by the second photodiode by the on / off operation of the second transfer transistor, a second floating diffusion which accumulates charge generated by the first floating diffusion, And a second reset transistor connected between the first photodiode and the power supply node, the first reset transistor being connected between the power supply node and the first reset transistor, And an overflow transistor for preventing saturation of the diode.

According to an embodiment of the present invention, light from an external light source, which generates a flicker phenomenon, is accurately detected by using charges generated in the first photodiode and the second photodiode included in each of the plurality of pixels of the image sensor . In addition, by controlling the exposure time of the first photodiode and the second photodiode differently, the dynamic range of the image sensor can be increased to improve the quality of the image generated by the image sensor

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a block diagram briefly showing an image sensor according to an embodiment of the present invention.
FIGS. 2 and 3 are simplified views of an image processing apparatus including an image sensor according to an embodiment of the present invention.
4 and 5 are simplified plan views illustrating a pixel array included in an image sensor according to an embodiment of the present invention.
6 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.
7 is a view for explaining the operation of the image sensor according to an embodiment of the present invention.
8 and 9 are views for explaining the operation of the image sensor according to an embodiment of the present invention.
10 to 12 are views for explaining the operation of the image sensor according to an embodiment of the present invention.
13 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.
FIGS. 14 through 17 are views for explaining the operation of the image sensor according to an embodiment of the present invention.
18 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.
19 and 20 are views for explaining the operation of the image sensor according to an embodiment of the present invention.
FIGS. 21 to 27 are views for explaining the operation of the image sensor according to an embodiment of the present invention.
28 is a block diagram briefly showing an electronic device including an image sensor according to an embodiment of the present invention.

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

1 is a block diagram briefly showing an image processing apparatus including an image sensor according to an embodiment of the present invention.

Referring to FIG. 1, an image processing apparatus 1 according to an embodiment of the present invention may include an image sensor 10, and an image processor 20. The image sensor 10 may include a pixel array 11, a row driver 12, a column driver 13, a lead-out circuit 14, a timing controller 15, and the like.

The image sensor 10 may operate according to a control command received from the image processor 20 and may convert the light transmitted from the object 30 into an electric signal and output the electric signal to the image processor 20. [ The pixel array 11 included in the image sensor 10 may include a plurality of pixels PX and the plurality of pixels PX may include a photodiode PD for receiving light to generate charges . In one embodiment, each of the plurality of pixels PX may comprise two or more photodiodes.

Each of the plurality of pixels PX may include a pixel circuit for generating an electric signal from a charge generated by the photodiode. In one embodiment, the pixel circuit may include a transfer transistor, a drive transistor, a select transistor, a reset transistor, and the like. When one pixel PX has two or more photodiodes, each pixel PX may include a pixel circuit for processing the charge generated in each of the two or more photodiodes. That is, when one pixel PX has two or more photodiodes, the pixel circuit may include at least two of at least some of the transfer transistor, the driving transistor, the selection transistor, and the reset transistor.

In an embodiment of the present invention, one pixel PX may include a first photodiode and a second photodiode. Further, in one embodiment of the present invention, one pixel PX includes a first pixel circuit for processing the charge generated in the first photodiode and a second pixel circuit for processing the charge generated in the second photodiode can do. Each of the first pixel circuit and the second pixel circuit may include a plurality of semiconductor elements. The first pixel circuit generates a first pixel signal from the charge generated in the first photodiode and outputs the first pixel signal to the first column line and the second circuit generates a second pixel signal from the charge generated in the second photodiode, 2 column lines. Each of the first pixel signal and the second pixel signal may include a reset voltage and a pixel voltage.

The row driver 12 may drive the pixel array 11 in a row unit. For example, the row driver 12 can generate a transfer control signal for controlling the transfer transistor of each pixel PX, a reset control signal for controlling the reset transistor, a selection control signal for controlling the selection transistor, and the like.

The column driver 13 may include a correlated double sampler (CDS), an analog-to-digital converter (ADC), and the like. The correlated dual sampler may perform correlated double sampling to obtain pixel signals through the column lines connected to the pixels PX included in the row selected by the row select signal supplied by the row driver 12. [ The analog-to-digital converter can convert the output of the correlated double sampler into a digital signal and deliver it to the lead-out circuit 14.

The lead-out circuit 14 may include a latch or buffer circuit capable of temporarily storing a digital signal, an amplification circuit, and the like, and may process the digital signal received from the column driver 13 to generate image data. The operation timings of the row driver 12, the column driver 13 and the lead-out circuit 14 can be determined by the timing controller 15 and the timing controller 15 can control the operation timings of the control commands . ≪ / RTI > The image processor 20 may process image data output from the lead-out circuit 14 and output it to a display device or the like, or may store the image data in a storage device such as a memory. Alternatively, when the image processing apparatus 1 is mounted on the autonomous driving vehicle, the image processor 20 may transmit the image data to the main controller for controlling the autonomous driving vehicle and the like.

2 is a simplified view of an image processing apparatus including an image sensor according to an embodiment of the present invention.

2, an image processing apparatus 2 according to an embodiment of the present invention includes a pixel array region 40, a logic circuit region 50 provided at a lower portion of the pixel array region 40, And a memory region 60 provided at a lower portion of the memory cell array 50. The pixel array region 40 and the logic circuit region 50 and the memory region 60 may be stacked on each other. In one embodiment, the pixel array region 40 and the logic circuit region 50 are stacked together at the wafer level, and the memory region 60 can be attached to the bottom of the logic circuit region 50 at the chip level.

The pixel array region 40 may include a sensing region SA where a plurality of pixels PX are provided and a first pad region PA1 provided around the sensing region SA. The first pad area PA1 includes a plurality of upper pads PAD and the plurality of upper pads PAD are connected to the second pad area PA2 of the logic circuit area 50 via a via VIA, And to the logic circuit LC.

Each of the plurality of pixels PX may include a photodiode for receiving light to generate charge, a pixel circuit for converting the charge generated by the photodiode into an electric signal, and the like. The photodiode may include an organic photodiode or a semiconductor photodiode, and in one embodiment, a plurality of semiconductor photodiodes may be included in each of the plurality of pixels PX. The pixel circuit may include a plurality of transistors for converting the charge generated by the photodiode into an electrical signal.

The logic circuit region 50 may include a plurality of circuit elements formed in the logic circuit LC. The plurality of circuit elements included in the logic circuit LC may provide circuits, such as a row driver, a column driver, and a timing controller, for driving pixel circuits provided in the pixel array region 40, for example. A plurality of circuit elements included in the logic circuit LC may be connected to the pixel circuit through the first and second pad regions PA1 and PA2.

The memory region 60 provided at the lower portion of the logic circuit region 50 includes a protection layer EN sealing the memory chip MC and the dummy chip DC and the memory chip MC and the dummy chip DC . The memory chip MC may be a dynamic random access memory (DRAM) or a static random access memory (SRAM), and the dummy chip DC may not have the function of actually storing data. The memory chip MC may be electrically connected to at least some of the circuit elements included in the logic circuit region 50 by bumps. In one embodiment, the bumps may be micro-bumps.

3, the image sensor 3 according to an exemplary embodiment of the present invention may include a first layer 70 and a second layer 80. Referring to FIG. The first layer 70 includes a sensing region SA in which a plurality of pixels PX are provided, a control logic region LC in which elements for driving the plurality of pixels PX are provided, And a first pad region PA1 provided around the control logic region LC. The first pad area PA1 includes a plurality of upper pads PAD and the plurality of upper pads PAD includes a memory chip MC provided in the second layer 80 via a via VIA, Can be connected. The second layer 80 may include a memory layer MC and a dummy chip DC and a protective layer EN sealing the memory chip MC and the dummy chip DC.

4 and 5 are simplified plan views illustrating a pixel array included in an image sensor according to an embodiment of the present invention.

Referring to FIG. 4, the pixel array 100 may include a plurality of pixels 110. The plurality of pixels 110 may be arranged in a matrix form along a plurality of rows and columns on the XY plane and may include a plurality of pixels 110 in order to prevent cross- May be formed. The isolation region 120 may include an insulating material such as an oxide and may be formed by a deep trench isolation (DTI). The sidewall of the isolation region 120 adjacent to the plurality of pixels 110 may be formed of a material having high reflectivity.

Each of the plurality of pixels 110 may include a photodiode that accepts light to generate a charge, and a plurality of semiconductor elements that convert charge generated in the photodiode into an electrical signal. For example, each of the plurality of pixels 110 may include a first photodiode 111 and a second photodiode 112. The first photodiode 111 and the second photodiode 112 may be disposed adjacent to each other on the X-Y plane.

In one embodiment, the first photodiode 111 may have a larger light receiving area than the second photodiode 112. Accordingly, the second photodiode 112 can be more easily and quickly saturated than the first photodiode 111. In an embodiment of the present invention, the first photodiode 111 is used for general image generation purposes, The second photodiode 112 can be used to accurately detect an external light source or assist in image generation regardless of a flicker phenomenon occurring in an external light source. When the image sensor according to an embodiment of the present invention is applied to an autonomous vehicle or the like, it is possible to accurately detect a signal lamp employing an LED in which a flicker phenomenon occurs as a light source, or a head lamp and a tail lamp of a nearby vehicle.

The second photodiode 112 has a light receiving area smaller than that of the first photodiode 111, so that it can be easily saturated. In an embodiment of the present invention, the second photodiode 112 may be saturated to prevent saturation of the second photodiode 112 or to prevent saturation of the second photodiode 112, Or means for generating accurate image data despite saturation of the second photodiode 112 may be provided.

The arrangement of the first photodiode 111 and the second photodiode 112 is not necessarily limited to that shown in FIG. 4, and may be variously modified. In the pixel array 100A according to the embodiment shown in Fig. 5, in the four pixels 110A adjacent to each other, the second photodiodes 112A may be arranged adjacent to each other. The second photodiode 112A has a light receiving area smaller than that of the first photodiode 111A and the isolation region 120A may be provided between the pixels 110A for the purpose of preventing crosstalk.

6 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.

Referring to FIG. 6, a pixel circuit 200 according to an embodiment of the present invention may include a first pixel circuit 210 and a second pixel circuit 220. The first pixel circuit 210 can output an electric signal using the charge generated by the first photodiode PD1 and the second pixel circuit 220 can charge the charge generated by the second photodiode PD2 So that an electric signal can be output. The first photodiode PD1 may have a larger light receiving area than the second photodiode PD2.

The first pixel circuit 210 may include a first reset transistor RX1, a first transfer transistor TX1, a driving transistor DX, and a selection transistor SX. The first photodiode PD1 may be connected to the first floating diffusion FD1 through the first transfer transistor TX1.

The first transfer transistor TX1 may transfer the charge accumulated in the first photodiode PD1 to the first floating diffusion FD1 based on the first transfer control signal TG1 transmitted from the row driver. The first photodiode PD1 can generate electrons as a main charge carrier. The driving transistor DX can operate as a source follower buffer amplifier by charges accumulated in the first floating diffusion FD1. The driving transistor DX can amplify the charge accumulated in the first floating diffusion FD1 and transfer it to the selection transistor SX.

The selection transistor SX can be operated by the selection control signal SEL input by the row driver and can perform switching and addressing operations. When the selection control signal SEL is applied from the row driver, a voltage may be output to the column line Col connected to the selection transistor SX. The voltage can be detected by a column driver and a lead-out circuit connected to the column line Col. The column driver and the lead-out circuit can detect the reset voltage in the state in which no charge is accumulated in the first floating diffusion FD1 and detect the pixel voltage in the state in which charges are accumulated in the first floating diffusion FD1 . In one embodiment, the image sensor may calculate the difference between the reset voltage and the pixel voltage to generate image data.

The second photodiode PD2 may be coupled to the overflow transistor OX and the second transfer transistor TX2 of the second pixel circuit 220. Similarly to the first photodiode PD1, the second photodiode PD2 can generate electrons as a main charge carrier. The charge generated in the second photodiode PD2 can move to the second floating diffusion FD2 when the second transfer transistor TX2 is turned on. The second photodiode PD2 can generate charge in response to the light while the second transfer transistor TX2 is turned off and the second photodiode PD2 is turned on every time the second transfer transistor TX2 is turned on, The charge generated in the second floating diffusion PD2 can be transferred to the second floating diffusion FD2 and accumulated.

In one embodiment, the overflow transistor OX may be provided for the purpose of preventing saturation of the second photodiode PD2. The overflow transistor OX repeatedly turns on and off periodically to remove at least part of the charge generated in the second photodiode PD2 and prevents saturation of the second photodiode PD2 can do. The second transfer transistor TX2 may be turned on while the overflow transistor OX is turned off to transfer the charge generated in the second photodiode PD2 to the second floating diffusion FD2. To prevent an unintended reset of the second floating diffusion FD2, the second transfer transistor TX2 and the overflow transistor OX may not be turned on at the same time. The charge of the second photodiode PD2 is accumulated in the second floating diffusion FD2 so that the charge generated in the first photodiode PD1 and the charge generated in the second photodiode PD2 are not combined The second reset transistor RX2 may be turned off.

In the embodiment shown in FIG. 6, the first photodiode PD1 and the second photodiode PD2 may share a column line Col. Thus, while the first pixel voltage corresponding to the charge of the first photodiode PD1 is output to the column line Col, the second photodiode PD2 can be separated from the column line Col. In one embodiment shown in FIG. 6, at least one of the second reset transistor RX2 and the second transfer transistor TX2 is turned off while the first pixel voltage is output to the column line Col, The photodiode PD2 can be separated from the column line Col. The first transfer transistor TX1 is turned on and is generated in the first photodiode PD1 to generate the first pixel voltage using the charge of the first photodiode PD1 and output it to the column line Col The accumulated charge can be accumulated in the first floating diffusion FD1.

Similarly, while the second pixel voltage corresponding to the charge of the second photodiode PD2 is output to the column line Col, the first photodiode PD1 may be separated from the column line Col. 6, the first transfer transistor TX1 is turned off so that the first photodiode PD1 is connected to the column line Col while the second pixel voltage is output to the column line Col. . The second transfer transistor TX2 and the second reset transistor RX2 are turned on to generate the second pixel voltage using the charge of the second photodiode PD2 and output it to the column line Col, 1 floating diffusion FD1 and the second floating diffusion FD2 can be connected to each other. The charge of the second photodiode PD2 can be accumulated in the first floating diffusion FD1 and the second floating diffusion FD2 and converted into a voltage by the driving transistor DX.

In one embodiment, the second photodiode PD2 may be used for the purpose of sensing an external light source exhibiting a flicker phenomenon, or for improving the dynamic range of the image sensor. In order to improve the dynamic range of the image sensor, when the first pixel voltage generated from the charge of the first photodiode PD1 is output a plurality of times, the second pixel voltage generated from the charge of the second photodiode PD2 It can be output only once.

The first photodiode PD1 may have a relatively larger area than the second photodiode PD2. In an embodiment of the present invention, an image expressing an external light source exhibiting a flicker phenomenon is generated using charges generated in the second photodiode PD2, while an electric charge generated in the first photodiode PD1 is generated in a normal It can be used to generate images. In addition, the dynamic range and the image quality of the image sensor can be improved by adjusting the exposure time of the first photodiode PD1 and the second photodiode PD2, respectively. The following description will be made with reference to Fig.

7 is a view for explaining the operation of the image sensor according to an embodiment of the present invention. In one embodiment, Figure 7 may be a timing diagram for illustrating the operation of the image sensor.

7, it is possible to improve the dynamic range of the image sensor and to generate an image that accurately represents the external light source in which the flicker phenomenon occurs. 7, the operation of the image sensor according to an embodiment of the present invention is such that the first reset transistor RX1 and the second reset transistor RX2 are turned on to turn on the first floating diffusion FD1 and the second floating diffusion FD1, The voltage of the floating diffusion FD2 can be started to be reset.

When the voltage of the floating diffusions FD1 and FD2 is reset, the second transfer transistor TX2 and the overflow transistor OX are alternately turned on and off so that the charge generated in the second photodiode PD2 Can be accumulated in the second floating diffusion FD2. The second reset transistor RX2 can maintain the turn-off state so that the charge accumulated in the second floating diffusion FD2 does not leak to the first floating diffusion FD1. On the other hand, the first reset transistor RX1 can maintain the turn-on state such that the voltage of the first floating diffusion FD1 can be sufficiently reset.

In the embodiment shown in FIG. 7, charges generated in the second photodiode PD2 over n times (n is a natural number) can be accumulated in the second floating diffusion FD2. Referring to FIG. 7, the second photodiode PD2 is exposed to light during a plurality of times d1, d2,? Dn-1, and dn to generate charges, and the second photodiode PD2 The charge can be accumulated in the second floating diffusion FD2 each time a plurality of times (d1, d2,? Dn-1, dn) elapse. Each of the plurality of times d1, d2,? Dn-1, dn may be set under a condition that the second photodiode PD2 is not saturated. However, according to the embodiment, charges generated in the second photodiode PD2 may be transferred to the second floating diffusion FD2 at a time.

The number of the plurality of times (d1, d2,? Dn-1, dn) and the respective lengths may be determined in consideration of the operating frequency and the duty ratio of the commercial LED. For example, when the operating frequency of the LED is about 100 Hz and the duty ratio is about 10% or less, the total sum of the plurality of times d1, d2,? Dn-1, dn is 10 msec or less and the plurality of times d1, d2 ,? dn-1, dn) number n can be determined to be 10 or more. By setting the plurality of times d1, d2,? Dn-1, dn as described above, at least one of the plurality of times d1, d2,? Dn-1, Can be overlapped. Accordingly, the first photodiode PD1 can generate charges in response to the light of the turned-on LED, and can accurately detect the light of the LED operating in the pulse-width-modulation manner.

 The image sensor turns off the first reset transistor RX1 and turns off the select transistor SX before the charge generated in the second photodiode PD2 is transferred to the second floating diffusion FD2 during the last nth time, So that the first reset voltage can be detected. The column driver and lead-out circuit connected to the column line (Col) of the pixel circuit may include a sampling circuit for detecting the voltage of the column line (Col). The sampling circuit can detect the first reset voltage during the first sampling time t1 when the reset voltage detection signal SHR has a HIGH logic value.

In one example, the reset voltage detected by the sampling circuit during the first sampling time tl may be the voltage of the first floating diffusion FD1. The first floating diffusion FD1 and the second floating diffusion FD2 can be reset together as the first and second reset transistors RX1 and RX2 are simultaneously turned on at the beginning of operation. Therefore, the voltage of the first floating diffusion FD1 detected during the first sampling time t1 can be selected as the first reset voltage.

When the charge generated in the second photodiode PD2 is accumulated n-th in the second floating diffusion FD2, the image sensor turns on the second reset transistor RX2 to accumulate in the second floating diffusion FD2 Lt; RTI ID = 0.0 > FD1. ≪ / RTI > At the same time, the image sensor can turn on the selection transistor SX to detect the first pixel voltage corresponding to the charge of the second photodiode PD1 through the column line Col. The sampling circuit can detect the pixel voltage during the second sampling time t2 when the pixel voltage detection signal SHS has a high logic value. The image sensor calculates the difference between the first reset voltage and the first pixel voltage detected in each of the first sampling time t1 and the second sampling time t2 to obtain a first row RAW necessary for generating an image, Data can be generated. The first row data may be data corresponding to charges generated by the second photodiode PD2 exposed to light in each of a plurality of times d1, d2,? Dn-1, dn.

On the other hand, while the charges generated in the second photodiode PD2 are accumulated in the second floating diffusion FD2 a plurality of times, the first transfer transistor TX1 can be turned on and off in order . For example, when the first reset transistor RX1 is turned on while the first transfer transistor TX1 is turned on, the charge existing in the first photodiode PD1 is removed and the first floating diffusion FD1 is turned off, Can be reset. Thereafter, the first transfer transistor TX1 is turned off so that the first photodiode PD1 and the first floating diffusion FD1 can be separated from each other. The first transfer transistor TX1 may be turned off for at least a portion of the time that the charge of the second photodiode PD2 accumulates on the second floating diffusion FD2 a plurality of times. While the first transfer transistor TX1 is turned off, the first photodiode PD1 may be exposed to light.

For example, the first photodiode PD1 may be exposed to light for generating the charge during the first exposure time de1. The first photodiode PD1 may have a relatively larger area than the second photodiode PD2 so that the first exposure time de1 is a time period during which the second photodiode PD2 is exposed to light for a plurality of times (d1, d2,? dn-1, dn), respectively. For example, the first exposure time de1 may be set to a time longer than the sum of the plurality of times d1, d2,? Dn-1, dn.

During the third sampling time t3 at which the reset voltage detection signal SHR has a high logic value before the first exposure time de1 ends, the image sensor sets the voltage of the first floating diffusion FD1 to the second reset Voltage can be detected. Referring to FIG. 7, the first reset transistor RX1 may be turned on before the third sampling time t3 so that the first floating diffusion FD1 may be reset. The third sampling time t3 may be defined as the time during the first exposure time de1. When the first exposure time de1 is ended, the first transfer transistor TX1 is turned on to turn on the first photodiode PD1 may transfer the charge generated during the first exposure time de1 to the first floating diffusion FD1.

The image sensor can detect the second pixel voltage corresponding to the charge that has moved to the first floating diffusion FD1 during the fourth sampling time t4 after the first transfer transistor TX1 is turned off. The image sensor calculates the difference between the second reset voltage and the second pixel voltage detected in each of the third sampling time t3 and the fourth sampling time t4 to generate second row data necessary for generating an image can do. When the fourth sampling time t4 is ended, by turning on the first transfer transistor TX1 and transferring the charge present in the first photodiode PD1 to the first floating diffusion FD1, (PD1) can be removed. Thereafter, the first reset transistor RX1 may be turned on to reset the first floating diffusion FD1.

On the other hand, the image sensor can expose the first photodiode PD1 to light for a second exposure time de2 shorter than the first exposure time de1 after the fourth sampling time t4 elapses, During the fifth sampling time t5 included in the second exposure time de2, the voltage of the first floating diffusion FD1 can be detected as the third reset voltage. Referring to FIG. 5, before the fifth sampling time t5 starts, the first reset transistor RX1 may be turned on to reset the first floating diffusion FD1. For example, the second exposure time de2 may be set to a time shorter than the sum of the plurality of times (d1, d2,? Dn-1, dn).

When the second exposure time de2 is terminated, the first transfer transistor TX1 is turned on and the charge generated by the first photodiode PD1 during the second exposure time de2 is applied to the first floating diffusion FD1, . The image sensor may detect the voltage of the first floating diffusion FD1 as the third pixel voltage during the sixth sampling time t6 after the first transfer transistor TX1 is turned off. The image sensor calculates the difference between the third reset voltage and the third pixel voltage detected at each of the fifth sampling time t5 and the sixth sampling time t6 to generate third row data necessary for generating an image can do.

In one embodiment, the image sensor may combine the first through third row data obtained in each of the plurality of pixels to obtain one image. As described above, the first to third row data may be data obtained by exposing the first and second photodiodes PD1 and PD2 to light for different exposure times. Thus, by combining the first through third row data to obtain one image, the dynamic range characteristic of the image can be improved.

7, the first row data corresponding to the intermediate exposure time is obtained by using the second photodiode PD2, and the first photodiode PD1 is used to obtain the long exposure time and the short exposure It is assumed that the second and third row data corresponding to each time are obtained, but it is not necessarily limited to such a form. That is, in various alternative embodiments, the second photodiode PD2 may be used to obtain raw data corresponding to a long exposure time or a short exposure time.

In addition, the first row data can be used as data for accurately reflecting a light source such as an LED or the like where a flicker phenomenon occurs in an image. In an embodiment of the present invention, since the second photodiode PD2 can be prevented from being saturated by using the overflow transistor OX, light of a light source such as an LED can be accurately detected even when the ambient illuminance is low . In addition, a first photodiode PD1 and a second photodiode PD2 are disposed in one pixel to generate a general image using the charges of the second photodiode PD2, and light of a light source such as an LED is detected The first photodiode PD1 is used for the purpose of solving the problem of sacrificing the frame rate of the image in order to detect light of a light source such as an LED.

8 and 9 are views for explaining the operation of the image sensor according to an embodiment of the present invention.

8 is a diagram for explaining the operation of a general image sensor. In one embodiment, the LEDs may operate in a Pulse Width Modulation (PWM) fashion. Therefore, as shown in Fig. 8, the LED can operate according to a period T having a turn-on time Ton and a turn-off time Toff.

First, referring to the first case (case 1) of FIG. 8, it is determined whether or not the LED of the image sensor is detected based on whether the exposure time when the photodiode included in the image sensor is exposed to light overlaps with the turn- Can be determined. For example, the first case (case 1) may correspond to a case in which the image sensor is highly illuminated and thus the exposure time of the photodiode may be set short. The first exposure time ex1 in the first case case 1 may overlap with the turn-on time Ton of the LED, and the light emitted from the photodiode during the first exposure time ex1 may be used to light Can be accurately detected.

On the other hand, the second exposure time ex2 of the first case case1 may not overlap with the turn-on time Ton of the LED. The duty ratio representing the ratio of the turn-on time (Ton) to the whole period (T) in the PWM method for driving the LED can not be 100%. Therefore, in the first case (case 1) in which the exposure times ex1 and ex2 are set to be short due to high illuminance, the exposure time of the photodiode as the second exposure time ex2 is shorter than the turn-on sampling time t1 of the LED A situation in which an error occurs may occur. Accordingly, the light of the LED can not be accurately detected by the image using the charge generated in the photodiode during the second exposure time ex2.

Next, the second case (case 2) of FIG. 8 may correspond to a case where the illuminance of the environment to be photographed by the image sensor is low. Therefore, as shown in FIG. 8, the exposure time of the photodiode can be selected to be very long. In the second case (case 2), as the photodiode is exposed long, the photodiode can be easily saturated, and as a result, the light of the LED may not be accurately detected.

9 is a view for explaining the operation of the image sensor according to an embodiment of the present invention. As described above, the image sensor according to an embodiment of the present invention includes a plurality of pixels, and each of the plurality of pixels may include a first photodiode and a second photodiode. The second photodiode has a relatively small area as compared with the first photodiode, and can be used for detecting a light source in which a flicker phenomenon occurs, such as an LED. 8, the LED may operate in a pulse-width-modulation manner, and a turn-on time Ton and a turn-off time Toff within one period T Lt; / RTI >

Referring to FIG. 9, the exposure time of the second photodiode PD2 may be shorter than the turn-on time Ton of the LED. As described above with reference to FIG. 7, the second photodiode PD2 may not be saturated by on / off operations of the transfer transistor and the overflow transistor, and may be exposed to light a plurality of times to generate charges have. The charge generated by the second photodiode PD2 can be accumulated in the floating diffusion every time the exposure time is completed. Therefore, the saturation of the second photodiode PD2 can be prevented regardless of the illuminance of the external environment to be photographed by the image sensor. The second photodiode PD2 is exposed to light for a plurality of short exposure times so that the turn-on time Ton of the LED and the exposure time of the second photodiode PD2 do not deviate from each other and a flicker phenomenon occurs LED light can be accurately detected.

10 to 12 are views for explaining the operation of the image sensor according to an embodiment of the present invention. 10 to 12 may be timing diagrams for explaining the operation of the image sensor having the pixel circuit according to the embodiment shown in Fig.

10, the operation of the image sensor according to an embodiment of the present invention is such that the first reset transistor RX1 and the second reset transistor RX2 are turned on to turn on the first floating diffusion FD1, 2 < / RTI > floating diffusion FD2 is reset. When the floating diffusions FD1 and FD2 are reset, the second transfer transistor TX2 and the overflow transistor OX are alternately turned on and off so that the charge generated in the second photodiode PD2 becomes the second Can be accumulated in the floating diffusion FD2. The second reset transistor RX2 can maintain the turn-off state so that the charge accumulated in the second floating diffusion FD2 is not leaked. On the other hand, the first reset transistor RX1 can maintain the turn-on state such that the voltage of the first floating diffusion FD1 can be sufficiently reset.

While the charge is accumulated in the second floating diffusion FD2, the first transfer transistor TX1 is turned off and the first photodiode PD1 is exposed to light to generate charge. The first photodiode PD1 may generate charge for the first exposure time de1 and then move the charge to the first floating diffusion FD1 in response to the turn-on operation of the first transfer transistor TX1 have.

In the embodiment shown in FIG. 10, the controller can obtain the first pixel voltage during the first sampling time t1 using the charge accumulated in the second floating diffusion FD2. The controller can generate the first row data using the difference between the first pixel voltage acquired during the first sampling time t1 and the reset voltage acquired during the second sampling time t2. The controller may also generate the second row data using the difference between the reset voltage obtained during the second sampling time t2 and the second pixel voltage obtained during the third sampling time t3. The charge of the first photodiode PD1 can be moved to the first floating diffusion FD1 by the first transfer transistor TX1 that is turned on between the second sampling time t2 and the third sampling time t3 , And the controller can obtain the second pixel voltage using the charge of the first floating diffusion FD1.

In the embodiment shown in Fig. 10, the reset voltage for generating the first row data and the reset voltage for generating the second row data may be shared. The controller may not separately detect the reset voltage before acquiring the first pixel voltage and may generate the first row data using the detected reset voltage after acquiring the first pixel voltage.

On the other hand, the controller can expose the first photodiode PD1 for the second exposure time de2 after acquiring the second pixel voltage and resetting the first photodiode PD1. The third pixel voltage can be detected during the fifth sampling time t5 by the charge generated in the first photodiode PD1 during the second exposure time de2. The controller can generate the third row data using the difference between the reset voltage and the third pixel voltage obtained during the fourth sampling time t4 preceding the fifth sampling time t5. The reset voltage obtained by the controller during the fourth sampling time t4 may be different from the reset voltage obtained by the controller during the second sampling time t2. The controller can generate one image using the first row data, the second row data, and the third row data.

11, the operation of the image sensor according to an exemplary embodiment of the present invention is such that the first reset transistor RX1 and the second reset transistor RX2 are turned on to turn on the first floating diffusion FD1, The voltage of the second floating diffusion FD2 can be started to be reset. 11, during the first sampling time t1 after the second reset transistor RX2 is turned off, the controller can acquire the first reset voltage from the first floating diffusion FD1 have. When the first sampling time t1 has elapsed, the second transfer transistor TX2 and the overflow transistor OX are alternately turned on and off so that the charge generated in the second photodiode PD2 becomes the second floating Diffusion FD2. ≪ / RTI >

That is, in the embodiment shown in Fig. 11, the controller can acquire the first reset voltage before the second photodiode PD2 is exposed to light to generate charge. The first reset voltage may be stored in a memory coupled to the image sensor and the controller may calculate the difference between the first pixel voltage and the first reset voltage acquired during the second sampling time t2 to obtain the first row data have. In one example, the first reset voltage may be stored in a line memory.

12 may correspond to one embodiment that utilizes the second photodiode PD2 only for the purpose of accurately detecting the light of the light source in which the flicker phenomenon occurs, regardless of the dynamic range improvement of the image. have. Referring to FIG. 12, after resetting the first floating diffusion FD1 and the second floating diffusion FD2, the charge generated in the second photodiode PD2 is reset a plurality of times To the second floating diffusion FD2. At this time, while the charge is accumulated in the second floating diffusion FD2, the first floating diffusion FD1 and the second floating diffusion FD2 are separated by turning off the second reset transistor RX2, The charge can be generated by exposing the diode PD1 to light. For example, the first photodiode PD1 may generate charge for a predetermined exposure time de.

The reset voltage and the pixel voltage detected from the first floating diffusion FD1 in each of the first sampling time t1 and the second sampling time t2 can be used to generate the first row data. The first row data can be used for the purpose of accurately detecting the light of the light source in which the flicker phenomenon appears. The second reset transistor RX2 is turned on for the second sampling time t2 or before the second sampling time t2 so that the second photodiode PD2 generates and accumulates in the second floating diffusion FD2 An electric charge can be shared with the first floating diffusion FD1.

On the other hand, when the second sampling time t2 elapses, the first reset transistor RX1 is turned on to reset the first floating diffusion FD1, and the third sampling time t3 and the fourth sampling time t4, It is possible to detect the reset voltage and the pixel voltage in each. The pixel voltage detected at the fourth sampling time t4 may be the voltage of the first floating diffusion FD1 according to the amount of charge accumulated in the first photodiode PD1 during the exposure time de. The image sensor can generate the second row data by calculating the difference between the reset voltage and the pixel voltage detected at each of the third sampling time t3 and the fourth sampling time t4. The second row data may be used to generate a generic image. In one example, when the image sensor generates the first row data once, the second row data may be generated a plurality of times. Therefore, it is possible to minimize the image frame rate degradation due to the generation of the first row data.

The embodiment shown in Fig. 12 may correspond to an embodiment that utilizes the second photodiode PD2 only for the purpose of improving the dynamic range of the image, without considering the light source in which the flicker phenomenon appears. Wherein the first row data may be image data generated during a relatively short exposure time and the second row data may be image data generated during a relatively long exposure time. The controller of the image sensor can improve the dynamic range of the image by generating one image using the first row data and the second row data.

13 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.

The pixel circuit 300 according to one embodiment shown in FIG. 13 may include a first pixel circuit 310 and a second pixel circuit 320. The first pixel circuit 310 may output an electric signal using the charge generated by the first photodiode PD1 and the second pixel circuit 320 may charge the charge generated by the second photodiode PD2 So that an electric signal can be output. The configuration of the transistors included in each of the first pixel circuit 310 and the second pixel circuit 320 may be similar to the embodiment shown in FIG.

However, unlike the embodiment shown in FIG. 6, in the embodiment shown in FIG. 13, the second reset transistor RX2 may be connected between the first floating diffusion FD1 and the second floating diffusion FD2 . That is, the second floating diffusion FD2 may be connected to the first reset transistor RX1, the second reset transistor RX2, and the second transfer transistor TX2. Hereinafter, the operation of the pixel circuit 300 according to the embodiment shown in FIG. 13 will be described with reference to FIGS. 14 to 17. FIG.

FIGS. 14 through 17 are views for explaining the operation of the image sensor according to an embodiment of the present invention.

14 to 17, it is possible to improve the dynamic range of the image sensor and to generate an image that accurately represents an external light source in which a flicker phenomenon occurs. 14, the operation of the image sensor according to an embodiment of the present invention is such that the first reset transistor RX1 and the second reset transistor RX2 are turned on to turn on the first floating diffusion FD1 and the second floating diffusion FD1. The voltage of the floating diffusion FD2 can be started to be reset.

When the voltages of the first and second floating diffusions FD1 and FD2 are reset, the second transfer transistor TX2 and the overflow transistor OX are alternately turned on and off to turn on the first photodiode PD2, Can be accumulated in the second floating diffusion FD2. Since the second floating diffusion FD2 is disposed between the first reset transistor RX1 and the second reset transistor RX2, the first reset transistor RX1 and the second reset transistor RX2 are turned off during charge accumulation in the second floating diffusion FD2. 2 reset transistor RX2 can be kept in the turn-off state.

In order to generate the first row data corresponding to the charge generated by the second photodiode PD2, the image sensor supplies the first reset voltage and the second reset voltage at the first sampling time t1 and the second sampling time t2, One pixel voltage can be detected. Each of the first sampling time t1 and the second sampling time t2 may be defined before and after the charge generated in the second photodiode PD2 is accumulated nth in the second floating diffusion FD2. In addition, since the charge accumulated in the second floating diffusion FD2 must be converted from the driving transistor DX to the voltage through the first floating diffusion FD1, the second reset transistor RX2 is turned on during the second sampling period t2, Can be turned on.

In the pixel circuit 300 according to the embodiment shown in FIG. 13, the second floating diffusion FD2 may be defined as a node between the first reset transistor RX1 and the second reset transistor RX2. Therefore, while the charges generated in the second photodiode PD2 accumulate in the second floating diffusion FD2 a plurality of times, the first reset transistor RX1 must maintain the turn-off state, The diode PD1 is exposed to light and can not generate electric charges. When the second sampling time t2 elapses, the first transfer transistor TX1 and the first reset transistor RX1 and the second reset transistor RX2 are turned on together to turn on the first photodiode PD1 and the first The floating diffusion FD1 can be reset.

When the first photodiode PD1 and the first floating diffusion FD1 are reset, the image sensor turns off the first transfer transistor TX1 so that the first photodiode PD1 is turned off during the first exposure time de1 It can be controlled to generate electric charges by being exposed to light. Before the first exposure time de1 ends, the image sensor can turn off the first and second reset transistors RX1 and RX2 and detect the second reset voltage from the first floating diffusion FD1 have. The second reset voltage can be detected during a third sampling time t3 at which the reset voltage detection signal SHR has a high logic value. For example, the first exposure time de1 may be set to a time longer than the sum of the plurality of times d1, d2,? Dn-1, dn.

When the first exposure time de1 elapses, the image sensor may turn on the first transfer transistor TX1 to transfer the charge accumulated in the first photodiode PD1 to the first floating diffusion FD1. The image sensor may detect the voltage of the first floating diffusion FD1 as the second pixel voltage for a fourth sampling time t4 after the first transfer transistor TX1 is turned off. The image sensor calculates the difference between the second reset voltage and the second pixel voltage detected in each of the third sampling time t3 and the fourth sampling time t4 to generate second row data necessary for generating an image can do.

When the fourth sampling time t4 is ended, the image sensor exposes the first photodiode PD1 to the light during the second exposure time de2, and the fifth sampling time t5 and the sixth sampling time t6, It is possible to detect the third reset voltage and the third pixel voltage in each. The second exposure time de2 may be set to a time shorter than the sum of the plurality of times d1, d2,? Dn-1, dn. The image sensor calculates the difference between the third reset voltage and the third pixel voltage detected in each of the fifth sampling time t5 and the sixth sampling time t6 to generate third row data necessary for generating an image .

In one embodiment, the image sensor may combine the first through third row data obtained in each of the plurality of pixels to obtain one image. As described above, the first to third row data may be data obtained by exposing the first and second photodiodes PD1 and PD2 to light for different exposure times. Thus, by combining the first through third row data to obtain one image, the dynamic range characteristic of the image can be improved.

In addition, the first row data can be used as data for accurately reflecting a light source such as an LED or the like where a flicker phenomenon occurs in an image. In an embodiment of the present invention, the second photodiode PD2 can be prevented from being saturated due to the overflow transistor OX, so that light of a light source such as an LED can be accurately detected even when the ambient illuminance is low. In addition, a second photodiode PD2 is provided in one pixel for the purpose of detecting light of a light source such as an LED, and a general image is generated using the first photodiode PD1. Thus, It is possible to solve the problem of sacrificing the frame rate of a general image in order to detect the light of the image.

In the embodiment shown in Fig. 15, unlike the embodiment shown in Fig. 14, the first reset voltage may not be detected while the charge of the second photodiode PD2 is accumulated in the second floating diffusion FD2 have. The controller can obtain the first pixel voltage for a first sampling time t1 after the charges generated in the second photodiode PD2 are accumulated n-th in the second floating diffusion FD2. The controller can calculate the difference between the reset voltage obtained during the second sampling time t2 and the first pixel voltage to obtain the first row data.

The controller may also obtain a second pixel voltage corresponding to the charge generated in the first photodiode PD1 during the first exposure time de1 for a third sampling time t3. The controller can calculate the difference between the reset voltage and the second pixel voltage obtained during the second sampling time t2 to obtain the second row data. That is, in the embodiment shown in Fig. 15, there may be one reset voltage necessary for acquiring each of the first row data and the second row data.

16, during the first sampling time t1 before the charges of the second photodiode PD2 are accumulated in the second floating diffusion FD2, unlike the embodiment shown in Fig. 14, The controller can obtain the first reset voltage. The controller can store the first reset voltage obtained during the first sampling time t1 in a separate memory and then calculate the difference between the first pixel voltage obtained during the second sampling time t2 and the first reset voltage Thereby generating first row data. The method of generating the second row data and the third row data may be the same as the embodiments described with reference to Figs. 14 and 15 above.

Next, one embodiment shown in FIG. 17 is an embodiment that utilizes the second photodiode PD2 only for the purpose of accurately detecting the light of the light source in which the flicker phenomenon occurs, regardless of the improvement of the dynamic range of the image Can respond. 17, after resetting the first floating diffusion FD1 and the second floating diffusion FD2, the charges generated in the second photodiode PD2 are applied to the second floating diffusion FD2 a plurality of times Can accumulate. The charge accumulated in the second floating diffusion FD2 can be shared by the first floating diffusion FD1 as the second reset transistor RX2 is turned on.

The first reset voltage and the first pixel voltage detected from the second floating diffusion FD1 in each of the first sampling time t1 and the second sampling time t2 can be used to generate the first row data have. The first row data can be used for the purpose of accurately detecting the light of the light source in which the flicker phenomenon appears.

On the other hand, when the second sampling time t2 ends, the first floating diffusion FD1 and the second floating diffusion FD2 are reset by turning on the first reset transistor RX1 and the second reset transistor RX2 , The third sampling time (t3), and the fourth sampling time (t4), respectively. The pixel voltage detected at the fourth sampling time t4 may be the voltage of the first floating diffusion FD1 according to the amount of charge accumulated in the first photodiode PD1 during the exposure time de. The image sensor can generate the second row data by calculating the difference between the reset voltage and the pixel voltage detected at each of the third sampling time t3 and the fourth sampling time t4. The second row data may be used to generate a generic image. In one example, when the image sensor generates the first row data once, the second row data may be generated a plurality of times. Therefore, it is possible to minimize the image frame rate degradation due to the generation of the first row data.

18 is a circuit diagram showing a pixel circuit included in an image sensor according to an embodiment of the present invention.

Referring to FIG. 18, a pixel circuit 400 according to an embodiment of the present invention may include a first pixel circuit 410 and a second pixel circuit 420. The first pixel circuit 410 may be a circuit for processing the charge generated in the first photodiode PD1 and the second pixel circuit 420 may be a circuit for processing the charge generated in the second photodiode PD2. Lt; / RTI >

The first pixel circuit 410 may include a first floating diffusion FD1, a first reset transistor RX1, a first transfer transistor TX1, a driving transistor DX, a selection transistor SX, . The second pixel circuit 420 includes a second floating diffusion FD2, a second reset transistor RX2, a second transfer transistor TX2, an overflow transistor OX, a storage capacitor SC, ), And the like. The operation of the active elements included in each of the first pixel circuit 410 and the second pixel circuit 420 can be controlled by a controller included in the image sensor.

In operation of the pixel circuit 400, the first pixel circuit 410 and the second pixel circuit 420 may share at least some of the circuit elements. For example, the second pixel circuit 420 can use the driving transistor DX and the selection transistor SX to output the pixel voltage corresponding to the charge generated by the second photodiode PD2. The first pixel circuit 410 also includes a second reset transistor RX2 and a second floating diffusion RX2 for adjusting the conversion gain or the capacitance of the charge generated by the first photodiode PD1, (FD2) can be used.

In one embodiment shown in FIG. 18, the second pixel circuit 420 may include a storage capacitor SC for storing charges generated by the second photodiode PD2. The storage capacitor SC may be implemented as a MIM capacitor or an active capacitor or the like. The storage capacitor SC may store the charge in response to the amount of charge generated in the second photodiode PD2 and the operation of the second transfer transistor TX2. A switch element SW is connected between the storage capacitor SC and the second floating diffusion FD2 and the charge of the storage capacitor SC is electrically connected to the second floating diffusion FD2 ).

The second photodiode PD2 has a relatively small light receiving area as compared with the first photodiode PD1, and therefore can be saturated more easily. 18, the charge of the second photodiode PD2 is removed by using the overflow transistor OX or the charge of the second photodiode PD2 is transferred to the storage capacitor SC The saturation of the second photodiode PD2 can be prevented. The image sensor including the pixel circuit 400 according to the embodiment shown in FIG. 18 improves the dynamic range by using charges generated in each of the first photodiode PD1 and the second photodiode PD2 At the same time, a light source such as an LED, in which a flicker phenomenon occurs, can be accurately captured.

19 and 20 are views for explaining the operation of the image sensor according to an embodiment of the present invention.

First, Fig. 19 may be a timing diagram for explaining the operation of the image sensor having the pixel circuit 400 according to the embodiment shown in Fig. 19, the operation of the image sensor according to an embodiment of the present invention is such that the first and second reset transistors RX1 and RX2 are turned on and the first and second floating diffusions FD1 and FD2 are turned on Can be started by resetting. At this time, the charge of the first photodiode PD1 may be removed by turning on the first transfer transistor TX1.

During the first exposure time de1 after the first transfer transistor TX1 is turned off, the first photodiode PD1 may be exposed to light. Then, the selection transistor SX can be turned on by the selection control signal SEL to detect the reset voltage and the pixel voltage. When the selection transistor SX is turned on, the first reset voltage and the first pixel voltage can be sequentially detected during the first time period D1. In one example, the sampling circuit of the controller can detect the first reset voltage during the first sampling time t1 when the reset voltage detection signal SHR has a high logic value. The controller can also detect the first pixel voltage for a second sampling time t2 at which the pixel voltage detection signal SHS has a high logic value. The first transfer transistor TX1 is turned on and off between the first sampling time t1 and the second sampling time t2 so that the first photodiode PD1 is turned off during the first exposure time de1 And the generated charge can move to the first floating diffusion FD1.

In the embodiment shown in Fig. 19, during the second time D2 after the first time D1, the image sensor can detect the pixel voltage and the reset voltage from the first photodiode PD1 once more . As shown in FIG. 19, when the second time D2 starts, the first reset transistor RX1 may be turned off and the second reset transistor RX2 may be turned on. Therefore, the sum of the first floating diffusion FD1, the second floating diffusion FD2 and the turn-on capacitance of the second reset transistor RX2 can be provided as a floating diffusion to the first photodiode PD1. As a result, in the second time D2, the charge of the first photodiode PD1 can be stored in the floating diffusion of a wider area than in the first time D1. Thus, the conversion gain of the pixel during the second time D2 may be less than the pixel conversion gain during the first time D1.

The sampling circuit of the image sensor can detect the second pixel voltage and the second reset voltage at each of the third sampling time t3 and the fourth sampling time t4. That is, at the second time D2, the pixel voltage can be detected before the reset voltage. The second pixel voltage may be a voltage corresponding to the charge generated in the first photodiode PD1 during the first exposure time de1 and the second exposure time de2. The second exposure time de2 may be shorter than the first exposure time de1.

Upon detecting the second pixel voltage, the controller resets the voltages of the first floating diffusion FD1 and the second floating diffusion FD2 by turning on and off the first reset transistor RX1, Voltage can be detected. At this time, to compensate for the coupling effect, the second reset transistor RX2 may be turned off for a period of time in which the first reset transistor RX1 is turned on. Referring to FIG. 19, at least a part of the turn-on time of the first reset transistor RX1 and the turn-off time of the second reset transistor RX2 may overlap each other within the second time D2.

In the embodiment shown in Fig. 19, image data can be generated using the reset voltage and pixel voltage detected under different conversion gain conditions. Therefore, saturation of the first photodiode PD1 and the first floating diffusion FD1 can be prevented, and the optimized image can be provided to the user irrespective of the illuminance of the environment in which the image sensor operates. In general, the capacitance of the first photodiode PD1 can be determined in accordance with the high-luminance condition that can be easily saturated. 19, before the pixel voltage and the reset voltage are read at the second time D1 so that the first floating diffusion FD1 is not saturated by the charge of the first photodiode PD1, 2 reset transistor RX2 to turn on the first floating diffusion FD1 and the second floating diffusion FD2. Therefore, the charge generated in the first photodiode PD1 can be sufficiently accumulated in the first floating diffusion FD1 and the second floating diffusion FD2, and the charges in the first floating diffusion FD1 and the second floating diffusion FD2 can be sufficiently accumulated, To generate an image, and to prevent saturation of the pixel. On the other hand, in the operation according to the embodiment shown in Fig. 19, the second photodiode PD2 may not be used.

20 is a diagram provided to explain the operation of the first photodiode PD1 and the floating diffusion. 20 (a) and 20 (b) respectively show the first photodiode PD1 and the floating diffusion at a first time D1 having a high conversion gain condition and a second time period D2 having a low conversion gain condition As shown in FIG.

Referring to FIG. 20A, the charges generated in the first photodiode PD1 can be transferred to the first floating diffusion FD1 at the first time D1. Since the second reset transistor RX2 is turned off during the first time D1, charges can accumulate only in the first floating diffusion FD1. The capacity of the first photodiode PD1 can be determined in consideration of a high conversion gain condition as shown in FIG. 20 (a), and therefore the capacity of the first floating diffusion FD1 and the capacity of the first photodiode PD1 can be determined, May be similar.

Next, referring to FIG. 20 (b), the second reset transistor RX2 is turned on at the second time D2 so that the first floating diffusion FD1 and the second floating diffusion FD2, as well as the second floating diffusion FD2, The turn-on capacitance of the reset transistor RX2 can be used as a floating diffusion. Therefore, a positive charge exceeding the capacity of the first photodiode PD1 can be accumulated in the floating diffusion and reflected in the pixel voltage through the driving transistor DX. In other words, according to the embodiment described with reference to FIGS. 19 and 20, it is possible to generate image data using a charge amount larger than that of the first photodiode PD1, thereby preventing saturation of pixels At the same time, the quality of the image data can be improved.

FIGS. 21 to 27 are views for explaining the operation of the image sensor according to an embodiment of the present invention. FIGS. 21-27 may be provided to illustrate different modes of operation of the image sensor, and the image sensor may have a pixel circuit 400 according to one embodiment shown in FIG.

21 and 22 are diagrams for explaining an operation mode in which the dynamic range of the image sensor can be improved by using the first photodiode PD1 and the second photodiode PD2. 21, in the operation mode for improving the dynamic range, the first reset transistor RX1 and the second reset transistor RX2 are simultaneously turned on and the first floating diffusion FD1 and the second floating diffusion FD2 can be reset. Also, while the first reset transistor RX1 and the second reset transistor RX2 are turned on, the first transfer transistor TX1 is turned on and off to charge the first photodiode PD1 Can be removed. The first exposure time de1 may start when the first transfer transistor TX1 is turned off.

When the first exposure time de1 elapses and the first transfer transistor TX1 is turned on, the charge generated in the first photodiode PD1 during the first exposure time de1 is transferred to the first floating diffusion FD1 Can be moved. The sampling circuit of the controller can detect the first reset voltage and the first pixel voltage in each of the first sampling time t1 and the second sampling time t2 of the first time D1. The first sampling time t1 is a time before the charge of the first photodiode PD1 is shifted to the first floating diffusion and the second sampling time t1 is a time before the charge of the first photodiode PD1 is shifted to the first floating diffusion. Lt; RTI ID = 0.0 > floating diffusion. ≪ / RTI > At least a part of the first time D1 to which the first sampling time t1 and the second sampling time t2 belong may overlap with the first exposure time de1. The controller may generate the first row data for generating an image using the difference between the first reset voltage and the first pixel voltage.

The controller can separate the first floating diffusion FD1 and the second floating diffusion FD2 by turning off the second reset transistor RX2 for the first time D1. Therefore, charges of the first photodiode PD1 can be accumulated only in the first floating diffusion FD1. When the first time D1 elapses, the controller can turn on the second reset transistor RX2 to reset the voltage of the first floating diffusion FD1.

Referring to FIG. 21, the second exposure time de2 may be started during the first exposure time de1. The second exposure time de2 is set such that the second transfer transistor TX2 and the switch element SW are turned on and off to turn on the second floating diffusion FD2, the storage capacitor SC, and the second photodiode PD2 May be reset. The second exposure time de2 may be shorter than the first exposure time de1.

The second pixel voltage corresponding to the charge generated by the second photodiode PD2 during the second exposure time de2 may be detected during the second time period D2. To detect the second pixel voltage, the first reset transistor RXl may be turned off to isolate the second floating diffusion FD2 from the power supply node. In addition, the second reset transistor RX2 may be turned on to couple the first floating diffusion FD1 and the second floating diffusion FD2.

When the second exposure time de2 elapses, the second transfer transistor TX2 and the switch element SW are turned on to transfer the charge of the second photodiode PD2 to the first floating diffusion FD1 and the second floating Diffusion FD2. ≪ / RTI > Then, during the third sampling time t3 of the second time D2, the sampling circuit can detect the second pixel voltage.

When the second pixel voltage is detected, the controller of the image sensor turns on the first reset transistor RX1 to reset the voltage of the first floating diffusion FD1 and the second floating diffusion FD2, the second reset voltage can be detected during the time t4. The controller may calculate the difference between the second pixel voltage and the second reset voltage to generate the second row data. The first reset transistor RX may be turned off during a fourth sampling time t4 for detecting the second reset voltage, and may be turned on again when the second reset voltage is detected.

When the second reset voltage is detected, the controller can expose the first photodiode PD1 to light during the third exposure time de3. The third exposure time de3 may be set to be shorter than the second exposure time de2 and the controller may set the first reset transistor RX1 and the second reset transistor RX2 before the third exposure time de3 starts, , And the first transfer transistor (TX1) to reset the first floating diffusion (FD1).

The controller can obtain the third reset voltage during the fifth sampling time t5 belonging to the third exposure time de3. When the third exposure time de3 is ended, the controller can move the charge of the first photodiode PD1 to the first floating diffusion FD1 and acquire the third pixel voltage for the sixth sampling time t6 have. During the third time D3 during which the controller acquires the third reset voltage and the third pixel voltage, the second reset transistor RX2 is turned off to turn off the first floating diffusion FD1 and the second floating diffusion FD2 Can be separated. The controller can calculate the difference between the third reset voltage and the third pixel voltage to obtain the third row data.

The controller can generate the image data using the first to third row data. Since the second exposure time de2 is set to be shorter than the first exposure time de1 and longer than the third exposure time de3, the first to third row data may correspond to charges generated during different exposure times. The controller combines the first through third row data to generate image data, whereby the dynamic range of the image sensor can be increased and the quality of the image can be improved.

Referring to FIG. 22, the other operation is the same as that of the embodiment shown in FIG. 21, but the operation of the overflow transistor OX may be different. In the embodiment shown in FIG. 21, the default state of the overflow transistor OX is turned off whereas in the embodiment shown in FIG. 22, the overflow transistor OX default state may be turned on. In the embodiment shown in Fig. 22, the overflow transistor OX maintains the turn-on state by default, and can be turned off for some time corresponding to the second exposure time de2. The second photodiode PD2 is exposed to light to generate charge during the second exposure time de2 so that the overflow transistor OX can be turned off for at least the second exposure time de2.

Next, the operation of the image sensor according to various embodiments of the present invention will be described with reference to FIGS. 23 to 27. FIG. In the embodiments shown in FIGS. 23 to 27, the image sensor can improve the dynamic range by using the second photodiode PD2, and at the same time, generate an image that accurately captures an external light source in which a flicker phenomenon appears .

Referring to FIG. 23, the controller of the image sensor turns on the first reset transistor RX1 and the second reset transistor RX2 to turn on the voltage of the first floating diffusion FD1 and the second floating diffusion FD2 Can be reset. The controller can also control the second photodiode PD2 to generate charge by alternately turning on and off the overflow transistor OX and the second transfer transistor TX2. The second photodiode PD2 can generate charges during the second exposure time de2 for a plurality of times. The switch element SW can be turned off while the overflow transistor OX and the second transfer transistor TX2 are alternately turned on and off. Therefore, the charge of the second photodiode PD2 can not move to the second floating diffusion FD2 and can be stored in the storage capacitor SC.

While the second photodiode PD2 generates charge, the controller can perform a shutter operation on the first photodiode PD1 by turning on and off the first transfer transistor TX1. Since the switch element SW is turned off, the shutter operation for the first photodiode PD1 may not affect the second photodiode PD2. When the shutter operation is completed, the first photodiode PD1 can generate charges for the first exposure time de1.

23, the controller controls the second reset transistor RX2 so that the first sub pixel voltage corresponding to the charge of the first photodiode PD1 and the second sub pixel voltage corresponding to the charge of the first photodiode PD1 while changing the area of the floating diffusion, The voltage can be detected over two times. Thus, the first subpixel voltage and the second subpixel voltage can be detected under different conversion gain conditions. By detecting the first subpixel voltage and the second subpixel voltage by changing the area of the floating diffusion, it is possible to prevent the first photodiode PD1 from being saturated and degrading the image quality under high light condition. The controller can obtain the first subpixel voltage and the second subpixel voltage in each of the first sub time DS1 and the second sub time DS2 of the first time D1.

First, when the first sub time DS1 is started during the first exposure time de1, the controller turns off the second reset transistor RX2 to turn off the first floating diffusion FD1 to the second floating diffusion FD2 And obtain the first sub reset voltage from the first floating diffusion FD1 during the first sampling time tl. When the first sampling time t1 elapses, the controller turns on the first transfer transistor TX1 to charge the first photodiode PD1 during the first exposure time de1 to the first floating diffusion FD1, and can detect the first sub-pixel voltage during the second sampling time t2.

Next, when the second sub time DS1 is started, the controller turns on the first reset transistor RX1 and turns on the second reset transistor RX2 to increase the area of the floating diffusion of the pixel, Can be lowered. Thus, a larger amount of charge can be stored in the floating diffusion of the pixel. The controller turns on the first transfer transistor TX1 to turn the charge of the first photodiode PD1 to the first floating diffusion FD1, the second floating diffusion FD2 and the turn-on second reset transistor RX2 ) Or the like.

The controller can detect the second subpixel voltage first during the third sampling time t3 and detect the second sub reset voltage during the subsequent fourth sampling time t4. The first reset transistor RX1 is turned on between the third sampling time t3 and the fourth sampling time t4 so that the voltages of the first floating diffusion FD1 and the second floating diffusion FD2 can be reset have. At this time, as described above with reference to Fig. 19, an operation of temporarily turning off the second reset transistor RX2 to cancel the coupling effect can be further performed.

The controller can generate the first row data using the difference between the first sub-reset voltage and the first sub-pixel voltage and the difference between the second sub-reset voltage and the second sub-pixel voltage. The first row data may be image data corresponding to charges generated by the first photodiode PD1 during the longest first exposure time de1.

At a second time D2 after the first time D1, the controller can detect the second pixel voltage corresponding to the charge of the second photodiode PD2. At the second time D2, the second reset transistor RX2 is turned on and the first reset transistor RX1 is turned off so that the first floating diffusion FD1 and the second floating diffusion FD2 can be connected . The charges generated by the second photodiode PD2 and stored in the storage capacitor SC during the second exposure time de2 for a plurality of times are applied to the first floating diffusion FD1 and the second floating diffusion FD2 in response to the turn- To the second floating diffusion FD2. Some of the charges may be stored in the second reset transistor RX2 turned on. For example, the switch element SW may be turned on after the last second exposure time de2 has elapsed. 23, it is assumed that the switch element SW is turned on with the second transfer transistor TX2. However, the switch element SW may be turned on before or after the second transfer transistor TX2 It may be turned on.

The controller turns off the second transfer transistor TX2 and turns on the overflow transistor OX to turn on the charge of the second photodiode PD2 while the switch element SW is kept in the turn- Can be removed. The controller can also detect the second pixel voltage during the fifth sampling time t5 and detect the second reset voltage during the sixth sampling time t6 after the fifth sampling time t5. Between the fifth sampling time t5 and the sixth sampling time t6, the controller turns on the first reset transistor RX1 to reset the first floating diffusion FD1 and the second floating diffusion FD2 .

The controller may calculate the difference between the second pixel voltage and the second reset voltage to generate the second row data. The second row data may be data corresponding to the charge generated in the second photodiode PD2 during the second exposure time de2 that is shorter than the first exposure time de1, and may correspond to the intermediate exposure time. Further, since the second photodiode PD2 controls the second photodiode PD2 to generate charges by setting the second exposure time de2 for a plurality of times, the external light source such as the LED, which generates the flicker phenomenon using the second row data, You can capture. The length and the number of times of the second exposure time de2 may be determined in consideration of the operating frequency and the duty ratio of the external light source such as an LED.

When entering the third time D3 after the second time D2, the controller can expose the first photodiode PD1 to light during the third exposure time de3. The third exposure time de3 may be shorter than the second exposure time de2. The first reset transistor RX1 is turned off and the second reset transistor RX2 is turned on during the third time period D3 as in the first time period D1 and the controller turns on the third reset voltage and the third pixel Voltage can be obtained in order. The controller can obtain the third row data using the difference between the third reset voltage and the third pixel voltage.

The controller can generate the image data using the first to third row data. The first to third row data can be obtained using the charges generated by the photodiodes PD1 and PD2 during the different exposure times de1 to de3. Therefore, by combining the first to third row data, It is possible to improve the dynamic range. Also, by controlling the second photodiode PD2 to generate charges over the second exposure time de2 for a plurality of times, it is possible to accurately capture the external light source where the flicker phenomenon occurs.

In the embodiment shown in Fig. 24, the image sensor can operate similarly to the embodiment shown in Fig. However, during the first time D1, the controller may detect the first reset voltage and the first pixel voltage once to generate the first row data corresponding to the first exposure time de1. 24, the unit integration time in which the overflow transistor OX and the second transfer transistor TX2 are alternately turned on and off is the same as that shown in FIG. 23 May be shorter than the embodiment. In addition, the operation in each of the second time D2 and the third time D3 may be similar to the embodiment shown in Fig.

In the embodiment shown in Fig. 25, the image sensor can operate similar to the embodiment shown in Fig. However, the first exposure time de1 may start earlier than the second exposure time de2. That is, in the embodiment shown in FIG. 25, the shutter operation for the first photodiode PD1 may be performed before the shutter operation for the second photodiode PD2. The unit integration time in the embodiment shown in Fig. 25 may be the same as or shorter than the embodiment shown in Fig.

In the embodiment shown in FIG. 25, the operation in the third time D3 may be different from the embodiments shown in FIG. 23 and FIG. Referring to FIG. 25, the first reset transistor RX1 may be turned on and the second reset transistor RX2 may be turned off during a third time period D3. Thus, the charge generated by the first photodiode PD1 during the third exposure time de3 can only accumulate in the first floating diffusion FD1, and the controller acquires the third pixel voltage in a relatively high conversion gain condition .

In the embodiments described with reference to FIGS. 23 to 25, the second photodiode PD2 can generate charges over a plurality of times by the overflow transistor OX and the second transfer transistor TX2. The ratio and number of turn-on times of the overflow transistor OX and the second transfer transistor TX2 can be determined in consideration of the operating frequency and the duty ratio of the external light source in which the flicker phenomenon occurs. Further, in another embodiment of the present invention, the second exposure time at which the second photodiode PD2 generates charge can be set sufficiently long to accurately capture the external light source in which the flicker phenomenon appears. The following description will be made with reference to Figs. 26 and 27. Fig.

Referring to FIG. 26, the operation of the image sensor is such that the controller turns on the first reset transistor RX1 and the second reset transistor RX2 to turn on the first floating diffusion FD1 and the second floating diffusion FD2 Can be initiated by resetting. The controller can then perform a shutter operation to turn on the second photodiode PD2 and the storage capacitor SC by turning on the second transfer transistor TX2 and the switch element SW together. When the shutter operation is completed, the second photodiode PD2 can generate charges for the second exposure time de2. The charge generated by the second photodiode PD2 during the second exposure time de2 may be stored in the storage capacitor SC by an overflow phenomenon.

During the second exposure time de2, the first photodiode PD1 may also generate charge. The first photodiode PD1 generates charge during the first exposure time de1 and the controller can detect the voltages necessary to generate the first row data during the first time D1. For example, the first time D1 includes a first sub-time DS1 and a second sub-time DS2, and the controller may compare the first sampling time t1 of the first sub- It is possible to detect the first sub reset voltage and the first sub pixel voltage at each time t2. In addition, the controller can detect the second sub-pixel voltage and the second sub-reset voltage in the third sampling time t3 and the fourth sampling time t4 of the second sub-time DS2, respectively. That is, the operation of the image sensor at the first time D1 may be similar to the embodiment shown in Fig. Similarly, the operation of the image sensor at the third time D3 may also be similar to the embodiment shown in Fig.

The second exposure time de2 may be terminated at a second time D2 after the first time D1. The second exposure time de2 is terminated by the turn-on operation of the second transfer transistor TX2 and the switch element SW can be turned on with the second transfer transistor TX2. As the switch element SW is turned on, the charge stored in the storage capacitor SC during the second exposure time de2 can move to the floating diffusion. Since the second reset transistor RX2 is turned on for the second time D2, the charge of the storage capacitor SC can move to the first floating diffusion FD1 and the second floating diffusion FD2. Some of the charges of the storage capacitor SC may be stored in the turn-on capacitance of the second reset transistor RX2.

The controller can detect the second pixel voltage during the fifth sampling time t5 of the second time D2 and detect the second reset voltage during the sixth sampling time t6. The second exposure time de2 may be determined in consideration of the operating frequency of the light source in which the flicker phenomenon occurs. For example, the second exposure time de2 may be set to be longer than the inverse number of the operation frequency of the light source in which the flicker phenomenon occurs, i.e., the operation period. Therefore, the light source can be accurately captured despite the flicker phenomenon.

26, the controller can generate the first to third row data using the difference between the reset voltages and pixel voltages obtained in each of the first to third times D1 to D3 have. The second row data can also be used as data for detecting the light source in which the flicker phenomenon appears. The controller can combine the first through third row data generated at different exposure times de1-de3 and conversion gain conditions to generate image data, thereby improving the dynamic range of the image sensor.

The operation of the image sensor according to the embodiment shown in FIG. 27 may be similar to the embodiment shown in FIG. However, at the first time D1, the controller can detect the first reset voltage and the first pixel voltage only once without changing the area of the floating diffusion. In the second time period D2, the second transfer transistor TX2 is turned on and off so that charges not transferred to the storage capacitor SC due to the overflow phenomenon are transferred to the storage capacitor SC The switch element SW can be turned on later. Other operations may be the same as the embodiment shown in Fig.

28 is a block diagram briefly showing an electronic device including an image sensor according to an embodiment of the present invention.

The computer device 1000 according to the embodiment shown in FIG. 28 may include a display 1010, an image sensor 1020, a memory 1030, a processor 1040, and a port 1050, and the like. In addition, the computer device 1000 may further include a wired / wireless communication device, a power supply device, and the like. Among the components shown in Fig. 28, the port 1050 may be a device in which the computer apparatus 1000 is provided for communicating with a video card, a sound card, a memory card, a USB device, and the like. The computer device 1000 may be a concept including both a general desktop computer and a laptop computer, as well as a smart phone, a tablet PC, and a smart wearable device.

The processor 1040 may perform particular operations, commands, tasks, and so on. The processor 1040 may be a central processing unit (CPU) or a microprocessor unit (MCU) and may be coupled to the display 1010, the image sensor 1020, the memory device 1030, Lt; RTI ID = 0.0 > a < / RTI >

The memory 1030 may be a storage medium for storing data necessary for the operation of the computer apparatus 1000, or multimedia data. Memory 1030 can include volatile memory, such as random access memory (RAM), or non-volatile memory, such as flash memory. The memory 1030 may also include at least one of a solid state drive (SSD), a hard disk drive (HDD), and an optical drive (ODD) as a storage device. The input / output device 1020 may include an input device such as a keyboard, a mouse, a touch screen, etc., and an output device, such as a display, an audio output, etc.,

The image sensor 1010 may be mounted on a package substrate and connected to the processor 1040 by a bus 1060 or other communication means. The image sensor 1010 may be employed in the computer apparatus 1000 in the form of various embodiments described with reference to FIGS.

The present invention is not limited to the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

1, 2: image processing device
10: Image sensor
100, 100A: pixel array
110, 110A: pixel
111, 111A, PD1: a first photodiode
112, 112A, PD2: a second photodiode
FD1: First Floating Diffusion
FD2: second floating diffusion
OX: Overflow transistor
RX1: first reset transistor
RX2: Second reset transistor
DX: driving transistor
SX: Select transistor
SW: Switch element
SC: storage capacitor
210, 310, 410: a first pixel circuit
220, 320, 420: a second pixel circuit

Claims (20)

A first photodiode coupled to the first floating diffusion through a first transfer transistor;
A second photodiode included in the same pixel as the first photodiode and connected to the second floating diffusion through a second transfer transistor and a switch element;
A pixel circuit having a first reset transistor coupled between the power node and the second floating diffusion, and a second reset transistor coupled between the first floating diffusion and the second floating diffusion; And
The second reset transistor is turned off for a first time to detect a first pixel voltage corresponding to the charge of the first floating diffusion, and when a second time after the first time starts, To detect a second pixel voltage corresponding to the charges of the first floating diffusion and the second floating diffusion; .
The method according to claim 1,
Wherein the controller turns on the first reset transistor and the second reset transistor to reset the first floating diffusion and the second floating diffusion before the first time begins.
The method according to claim 1,
Wherein the controller detects a first reset voltage before detecting the first pixel voltage for the first time and detects a second reset voltage after detecting the second pixel voltage for the second time.
The method of claim 3,
Wherein the controller detects the second pixel voltage and then turns on the first reset transistor to reset the first floating diffusion and the second floating diffusion.
5. The method of claim 4,
And the controller turns on the first reset transistor and then turns off the second reset transistor.
6. The method of claim 5,
Wherein at least a part of the turn-on time of the first reset transistor and the turn-off time of the second reset transistor overlap each other within the second time period.
The method according to claim 1,
Wherein the controller detects the voltage generated by the charge generated during the first exposure time of the first photodiode with the first pixel voltage and the second photodiode detects the second exposure time when the second photodiode is shorter than the first exposure time Wherein the second pixel voltage is a voltage generated by the charge generated during the second pixel voltage.
8. The method of claim 7,
Wherein the controller is configured to: turn off the first reset transistor and turn off the second reset transistor when the third time begins after the second time to turn off the third pixel corresponding to the charge of the first floating diffusion, Image sensor for detecting voltage.
9. The method of claim 8,
Wherein the controller detects, as the third pixel voltage, a voltage generated by the charge generated by the first photodiode during a third exposure time shorter than the second exposure time.
8. The method of claim 7,
Wherein the controller turns off the first reset transistor and turns on the second reset transistor when a third time begins after the second time to turn on the third pixel corresponding to the charge of the first floating diffusion, Image sensor for detecting voltage.
11. The method of claim 10,
Wherein the controller detects, as the third pixel voltage, a voltage generated by the charge generated by the first photodiode during a third exposure time shorter than the second exposure time.
11. The method of claim 10,
Wherein the first time comprises a first sub-time and a second sub-time after the first sub-time,
The controller turns off the second reset transistor and detects a first subpixel voltage during the first sub-time, turns on the second reset transistor during the second sub-time, and turns on the second sub- Image sensor to detect.
13. The method of claim 12,
The controller detects a first sub-reset voltage before detecting the first sub-pixel voltage during the first sub-time, detects the second sub-pixel voltage during the second sub-time, Is detected.
The method according to claim 1,
The pixel circuit having an overflow transistor coupled between the second photodiode and the power node, and a storage capacitor coupled to a node between the switch element and the second transfer transistor.
15. The method of claim 14,
The controller may alternately turn on and off the overflow transistor and the second transfer transistor to store charges generated in the second photodiode in the storage capacitor,
And turns on the switch element for the second time to detect the voltage corresponding to the charge stored in the storage capacitor as the second pixel voltage.
15. The method of claim 14,
Wherein the controller stores charges generated in the second photodiode in the storage capacitor by turning off the overflow transistor and turning the second transfer transistor on and off,
And turns on the switch element for the second time to detect the voltage corresponding to the charge stored in the storage capacitor as the second pixel voltage.
17. The method of claim 16,
Wherein the first exposure time at which the first photodiode generates charge is shorter than the second exposure time at which the second photodiode generates charge.
A first photodiode and a second photodiode included in one pixel;
A first floating diffusion coupled to the first photodiode through a first transfer transistor;
A second floating diffusion coupled to the second photodiode through a second transfer transistor and a switch element;
A storage capacitor connected between a node between the second transfer transistor and the switch element and a power node supplying a power supply voltage;
A first reset transistor coupled between the second floating diffusion and the power supply node; And
A second reset transistor coupled between the first floating diffusion and the second floating diffusion; ≪ / RTI >
A first photodiode;
A second photodiode included in the same pixel as the first photodiode;
A pixel circuit coupled to the first photodiode and the second photodiode, the pixel circuit generating a pixel voltage corresponding to charges of the first photodiode and the second photodiode; And
Obtaining a first pixel voltage from the charge generated by the first photodiode during a first exposure time and generating a second pixel voltage from a charge generated by the second photodiode during a second exposure time that is less than the first exposure time Obtaining a third pixel voltage from the charge generated by the first photodiode during a third exposure time that is shorter than the second exposure time, and using the first through third pixel voltages to generate image data ; .
20. The method of claim 19,
Wherein the controller obtains a first subpixel voltage and a second subpixel voltage by applying a first conversion gain and a second conversion gain to the charges generated by the first photodiode during the first exposure time, respectively.

Images