KR100785528B1 - Image sensor and pixel array of image sensors with wide operating range - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor having a wide operating range and a pixel array of the image sensor. In particular, an image having a wide illumination range is generated by acquiring and combining images having different exposure levels through pixel pairs having different exposure levels. It's about technology.

The pixel array of the image sensor according to the present invention is characterized in that the unit pixel groups composed of a plurality of pixels arranged adjacent to each other on the same row have different exposure times, and are arranged in a grid.

In addition, an image sensor according to the present invention includes a pixel array in which a unit pixel group including a plurality of pixels having different exposure times is arranged in a lattice shape; A row driver for generating driving signals for operation of the pixel array; And an output circuit for receiving a sensing signal output from the pixel array and separating and outputting an even column signal and an odd column signal.

Description

WIDE DYNAMIC RANGE IMAGE SENSOR AND PIXEL ARRAY OF IMAGE SENSOR}

1 is a block diagram showing an image sensor for varying the degree of exposure for each column according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an output example of an image by the image sensor of FIG. 1. FIG.

3 is a circuit diagram of pixel pairs of an image sensor for varying the degree of exposure for each column.

4 is another circuit diagram of a pixel pair of an image sensor for varying the degree of exposure for each column.

5 is a block diagram illustrating an image sensor for varying an exposure level for each row according to an exemplary embodiment of the present invention.

FIG. 6 is a diagram illustrating an output example of an image by the image sensor of FIG. 5. FIG.

7 is a circuit diagram of a pixel pair of an image sensor for varying the degree of exposure for each row.

8 is another circuit diagram of a pixel pair of an image sensor that varies the degree of exposure on a row-by-row basis.

<Description of Signs of Major Parts of Drawings>

10,310: low driver 20,320: pixel array

30,330: Output circuit

100,101,200,201,400,401,500,501: Photodiode

110,111,410,411: transfer transistor

120,121,210,211,420,421,510,511: reset transistor

130,131,220,221,430,431,520,521: drive transistor

140,141,230,231,440,441,530,531: selector transistor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor having a wide operating range and a pixel array of the image sensor. In particular, an image having a wide illumination range is generated by acquiring and combining images having different exposure levels through pixel pairs having different exposure levels. It's about technology.

In general, an image sensor refers to a device that captures an image by using a property of a semiconductor device that responds to energy of light. Light generated from each subject existing in the natural world has a unique value in wavelength and the like. The pixel of the image sensor detects light generated from each subject and converts it into an electrical signal. That is, the pixel of the image sensor generates an electrical signal according to the wavelength of light generated from the subject. The image sensor recognizes an image of the subject by using the electrical signal.

However, the general image sensor has a limitation in the band of illuminance that can be recognized. In other words, if you shoot an image where extremely bright and dark parts coexist, the bright parts are well expressed and the dark parts are generally black, or the objects in the dark parts are well distinguished, but the bright parts are all white. Thus, there is a problem that it is difficult to obtain information of both dark and bright parts without loss.

In order to solve the above problems, the present invention obtains an image having different exposure levels through a pair of pixels having different exposure levels, and combines an image sensor and an image sensor having a wide operating range capable of generating an image of a wide illumination range. It is an object to provide a pixel array of.

The pixel array of the image sensor according to the present invention is characterized in that the unit pixel groups composed of a plurality of pixels arranged adjacent to each other on the same row have different exposure times, and are arranged in a grid.

In addition, an image sensor according to the present invention includes a pixel array in which a unit pixel group including a plurality of pixels having different exposure times is arranged in a lattice shape; A row driver for generating driving signals for operation of the pixel array; And an output circuit for receiving a sensing signal output from the pixel array and separating and outputting an even column signal and an odd column signal.

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

1 is a block diagram illustrating an image sensor for varying an exposure degree for each column according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an image sensor having a different exposure level for each column includes a row driver 10, a pixel array 20, and an output circuit 30.

The row drive 10 generates and outputs a driving signal necessary for the operation of the pixel array 20.

The pixel array 20 is composed of pixels consisting of a plurality of rows and columns. Each row of pixels is paired by two pixels that recognize the same color (unit pixel group), and a pair of pixels that recognizes a different color. Are alternately arranged. That is, if R (Red), G (Green), B (Blue) pixels, each row is formed in a pattern such as RRGGRRGG ..., GGBBGGBB .... Each of the two pixels in the pixel pair has a different exposure time.

Here, although the unit pixel group is composed of two pixels, the unit pixel group may include three or more pixels. In this case, three or more pixels have different exposure times.

The output circuit 30 receives a sensing signal output from the pixel array 20, and separates and outputs an even column signal and an odd column signal.

FIG. 2 is a diagram illustrating an output example of an image by the image sensor of FIG. 1.

Referring to FIG. 2, if the pixel array is composed of 1280 * 480 pixels, the pixel array is separated into 640 * 480 pixel signals of even columns having different exposure levels and 640 * 480 pixel signals of odd columns.

3 is a circuit diagram of a pixel pair of an image sensor for varying the degree of exposure for each column.

Referring to FIG. 3, each pixel includes a photodiode 100, 101, a transfer transistor 110, 111, a reset transistor 120, 121, a drive transistor 130, 131, and a selector transistor 140, 141.

The photodiodes 100 and 101 absorb external light to generate photocharges.

The transfer transistors 110 and 111 selectively transfer photocharges from the photodiodes 100 and 101 to the sensing nodes N1 and N2.

The reset transistors 120 and 121 are connected between the power supply terminal VDD and the sensing nodes N1 and N2 to reset the sensing nodes N1 and N2.

One side of the drive transistors 130 and 131 is connected to the power supply terminal VDD, and transmits and amplifies an electrical signal corresponding to the sensing nodes N1 and N2.

The select transistors 140 and 141 are connected to the other side of the drive transistors 130 and 131 and output a sensed signal.

The first transmission signal TX1, the second transmission signal TX2, the reset signal RS, and the line select signal LS output from the row driver 10 are applied to each pixel pair as follows.

The first transmission signal TX1 is applied to the gate of the transmission transistor 110 of the first pixel (odd column) of the pixel pair.

The second transfer signal TX2 is applied to the gate of the transfer transistor 111 of the second pixel (even column) of the pixel pair.

The reset signal RS is commonly applied to the gates of the first reset transistor 120 and the second reset transistor 121 of the pixel pair.

The line select signal LS is commonly applied to the gates of the first select transistor 140 and the second select transistor 141 of the pixel pair.

The exposure time of each pixel is a time from when the reset signal RS and the transmission signals TX1 and TX2 are simultaneously enabled, until the line select signal LS is enabled and the sensed signal is output.

Since the line select signal LS is commonly enabled for the pixels of the even columns and the odd columns, the first transmission signal TX1 and the second transmission signal TX2 are constant while the reset signal RS is enabled. When enabled at time intervals, the exposure degree of pixels of even and odd columns is changed by the time interval.

4 is another circuit diagram of pixel pairs of an image sensor for varying the degree of exposure for each column.

Referring to FIG. 4, each pixel includes photodiodes 200 and 201, reset transistors 210 and 211, drive transistors 220 and 221, and selector transistors 230 and 231.

The photodiodes 200 and 201 absorb light from outside to generate photocharges.

The reset transistors 210 and 211 are connected between the power supply terminal VDD and the sensing nodes N3 and N4 to reset the sensing nodes N3 and N4.

One side of the drive transistors 220 and 221 is connected to the power supply terminal VDD, and transmits and amplifies an electrical signal corresponding to the sensing nodes N3 and N4.

The select transistors 230 and 231 are connected to the other side of the drive transistors 220 and 221 and output a sensed signal.

The first reset signal RS1, the second reset signal RS2, and the line select signal LS output from the row driver 10 are applied to each pixel pair as follows.

The first reset signal RS1 is applied to the gate of the reset transistor 210 of the first pixel (odd column) of the pixel pair.

The second reset signal RS2 is applied to the gate of the reset transistor 211 of the second pixel (even column) of the pixel pair.

The line select signal LS is applied to the gates of the first select transistor 230 and the second select transistor 231 of the pixel pair.

The exposure time of each pixel is a time from when the reset signals RS1 and RS2 are enabled until the line select signal LS is enabled and the sensed signal is output.

Since the line select signal LS is commonly enabled for the pixels of the even column and the odd column, when the first reset signal RS1 and the second reset signal RS2 are enabled at a predetermined time interval, the time interval is As a result, the exposure degree of pixels of even and odd columns is changed.

5 is a block diagram illustrating an image sensor for varying an exposure level for each row according to an exemplary embodiment of the present invention.

Referring to FIG. 5, an image sensor having a different exposure level for each row includes a row driver 310, a pixel array 320, and an output circuit 330.

The row drive 310 generates and outputs a driving signal necessary for the operation of the pixel array 320.

The pixel array 320 is composed of pixels consisting of a plurality of rows and columns. Each column of pixels is paired by two pixels that recognize the same color (a unit pixel group), and a pair of pixels that recognizes a different color. Are alternately arranged. That is, if R (Red), G (Green), B (Blue) pixels, each column is formed in a pattern such as RRGGRRGG ..., GGBBGGBB .... Each of the two pixels in the pixel pair has a different exposure time.

Here, although the unit pixel group is composed of two pixels, the unit pixel group may include three or more pixels. In this case, three or more pixels have different exposure times.

The output circuit 330 receives a sensing signal output from the pixel array 320 and separates an even row signal and an odd row signal and outputs the separated signal.

6 is a diagram illustrating an output example of an image by the image sensor of FIG. 5.

Referring to FIG. 6, if the pixel array is composed of 640 * 960 pixels, the pixel array may be divided into an even row of 640 * 480 pixel signals and an odd row of 640 * 480 pixel signals.

7 is a circuit diagram of a pixel pair of an image sensor for varying the degree of exposure for each row.

Referring to FIG. 7, each pixel includes a photo diode 400, 401, a transfer transistor 410, 411, a reset transistor 420, 421, a drive transistor 430, 431, and a selector transistor 440, 441.

The photodiodes 400 and 401 absorb light from outside to generate photocharges.

The transfer transistors 410 and 411 selectively transfer the photocharges from the photodiodes 400 and 401 to the sensing nodes N5 and N6.

The reset transistors 420 and 421 are connected between the power supply terminal VDD and the sensing nodes N5 and N6 to reset the sensing nodes N5 and N6.

One side of the drive transistors 430 and 431 is connected to the power supply terminal VDD, and transmits and amplifies an electrical signal corresponding to the sensing nodes N5 and N6.

The select transistors 440 and 441 are connected to the other side of the drive transistors 430 and 431 and output the sensed signals.

The first transmission signal TX1, the second transmission signal TX2, the first reset signal RS1, the second reset signal RS2, and the line select signal LS output from the row driver 310 are as follows. Applied to each pair of pixels.

The first transfer signal TX1 is applied to the gate of the transfer transistor 410 of the first pixel (odd row) of the pixel pair.

The second transfer signal TX2 is applied to the gate of the transfer transistor 411 of the second pixel (even row) of the pixel pair.

The first reset signal RS1 is applied to the gate of the reset transistor 420 of the first pixel (odd row) of the pixel pair.

The second reset signal RS2 is applied to the gate of the reset transistor 421 of the second pixel (even row) of the pixel pair.

The line select signal LS is commonly applied to the gates of the first select transistor 440 and the second select transistor 441 of the pixel pair.

The exposure time of each pixel is a time from when the reset signals RS1 and RS2 and the transmission signals TX1 and TX2 are simultaneously enabled until the line select signal LS is enabled and the sensed signal is output.

Since the line select signal LS is commonly enabled for the pixels of even and odd rows, when the first transmission signal TX1 and the second transmission signal TX2 are enabled at a predetermined time interval, The exposure of the pixels on even and odd rows will be different.

8 is another circuit diagram of a pixel pair of an image sensor for varying the degree of exposure for each row.

Referring to FIG. 8, each pixel includes a photodiode 500, 501, reset transistors 510, 511, drive transistors 520, 521, and selector transistors 530, 531.

The photodiodes 500 and 501 absorb light from outside to generate photocharges.

The reset transistors 510 and 511 are connected between the power supply terminal VDD and the sensing nodes N7 and N8 to reset the sensing nodes N7 and N8.

One side of the drive transistors 520 and 521 is connected to the power supply terminal VDD, and transmits and amplifies an electrical signal corresponding to the sensing nodes N7 and N8.

The select transistors 530 and 531 are connected to the other side of the drive transistors 520 and 521, and output the sensed signals.

The first reset signal RS1, the second reset signal RS2, and the line select signal LS output from the row driver 310 are applied to each pixel pair as follows.

The first reset signal RS1 is applied to the gate of the reset transistor 510 of the first pixel (odd row) of the pixel pair.

The second reset signal RS2 is applied to the gate of the reset transistor 511 of the second pixel (even row) of the pixel pair.

The line select signal LS is applied to the gates of the first select transistor 530 and the second select transistor 531 of the pixel pair.

The exposure time of each pixel is a time from when the reset signals RS1 and RS2 are enabled until the line select signal LS is enabled and the sensed signal is output.

Since the line select signal LS is commonly enabled for the pixels of even and odd rows, when the first reset signal RS1 and the second reset signal RS2 are enabled at a predetermined time interval, the time interval is As a result, the exposure degree of pixels of even rows and odd rows is changed.

Effects of the image sensor having a wide operating range and the pixel array of the image sensor according to the present invention are as follows.

First, an image having a wide exposure range may be generated by acquiring and combining an image having different exposure levels through pixel pairs having different exposure levels.

Second, there is no need to use a separate frame buffer to store multiple images.

In addition, a preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, replacements and additions through the spirit and scope of the appended claims, such modifications and changes are the following claims It should be seen as belonging to a range.

Claims (13)

delete And a unit pixel group consisting of a plurality of pixels arranged adjacently on the same row with different exposure times and arranged in a lattice pattern. A pixel array of claim 2; A row driver for generating a driving signal for operation of the pixel array; And An output circuit which receives a sensing signal output from the pixel array and separates and outputs an even column signal and an odd column signal Image sensor comprising a. The method of claim 3, wherein Each pixel is A photodiode that absorbs external light and generates photocharges; A transfer transistor for selectively transferring photocharge from the photodiode to a sensing node; A reset transistor connected between a power supply terminal and the sensing node to reset the sensing node; A drive transistor having one side connected to a power supply terminal and configured to transmit and amplify an electrical signal corresponding to the sensing node; And And a select transistor connected to the other side of the drive transistor and outputting a sensed signal. The method of claim 4, wherein The unit pixel group consists of two pixel pairs, A first transmission signal is applied to the gate of the transfer transistor of the first pixel of the pixel pair, A second transmission signal is applied to the gate of the transfer transistor of the second pixel of the pixel pair, A reset signal is commonly applied to the gates of the first and second reset transistors of the pixel pair, And a line select signal is commonly applied to the gates of the first and second select transistors of the pixel pair. The method of claim 3, wherein Each pixel is A photodiode that absorbs external light and generates photocharges; A reset transistor connected between a power supply terminal and a sensing node to reset the sensing node; A drive transistor having one side connected to a power supply terminal and configured to transmit and amplify an electrical signal corresponding to the sensing node; And And a select transistor connected to the other side of the drive transistor and outputting a sensed signal. The method of claim 6, The unit pixel group consists of two pixel pairs, A first reset signal is applied to the gate of the reset transistor of the first pixel of the pixel pair, A second reset signal is applied to the gate of the reset transistor of the second pixel of the pixel pair, And a line select signal is commonly applied to the gates of the first and second select transistors of the pixel pair. The method of claim 2, And a plurality of pixels of the unit pixel group are arranged adjacent to the same column. A pixel array of claim 8; A row driver for generating a driving signal for operation of the pixel array; And An output circuit which receives a sensing signal output from the pixel array and separates an even row signal and an odd row signal Image sensor comprising a. The method of claim 9, Each pixel is A photodiode that absorbs external light and generates photocharges; A transfer transistor for selectively transferring photocharge from the photodiode to a sensing node; A reset transistor connected between a power supply terminal and the sensing node to reset the sensing node; A drive transistor having one side connected to a power supply terminal and configured to transmit and amplify an electrical signal corresponding to the sensing node; And And a select transistor connected to the other side of the drive transistor and outputting a sensed signal. The method of claim 10, The unit pixel group consists of two pixel pairs, A first transmission signal is applied to the gate of the transfer transistor of the first pixel of the pixel pair, A second transmission signal is applied to the gate of the transfer transistor of the second pixel of the pixel pair, A first reset signal is applied to the gate of the reset transistor of the first pixel of the pixel pair, A second reset signal is applied to the gate of the reset transistor of the second pixel of the pixel pair, And a line select signal is commonly applied to the gates of the first and second select transistors of the pixel pair. The method of claim 9, Each pixel is A photodiode that absorbs external light and generates photocharges; A reset transistor connected between a power supply terminal and a sensing node to reset the sensing node; A drive transistor having one side connected to a power supply terminal and configured to transmit and amplify an electrical signal corresponding to the sensing node; And And a select transistor connected to the other side of the drive transistor and outputting a sensed signal. The method of claim 12, The unit pixel group consists of two pixel pairs, A first reset signal is applied to the gate of the reset transistor of the first pixel of the pixel pair, A second reset signal is applied to the gate of the reset transistor of the second pixel of the pixel pair, And a line select signal is commonly applied to the gates of the first and second select transistors of the pixel pair.

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