KR100248616B1 - Linear sensor having a plurality of sensor rows - Google Patents

Abstract

The present invention provides a linear sensor for sampling substantially vertically corresponding pixels of a plurality of sensor rows arranged in a vertical direction. A plurality of horizontal transfer registers and a plurality of shift gates are disposed corresponding to the plurality of sensor strings. At one end of the plurality of horizontal transfer registers, a vertical transfer register is disposed. In the vertical transfer register, signal charges transmitted by the plurality of horizontal transfer registers are sequentially transferred in the vertical direction. The charge / voltage conversion section is disposed on the output side of the vertical transfer register. The signal charges accumulated in the vertically corresponding pixels are sequentially transmitted to the charge / voltage conversion section.

Description

Linear sensor with multiple sensor strings

1 is a block diagram of a conventional linear sensor.

2 is a timing chart for explaining the operation of the conventional linear sensor.

3 is a configuration diagram of another conventional linear sensor.

4 is a timing chart for explaining the operation of another conventional linear sensor.

5 is a configuration diagram of a first embodiment of the linear sensor of the present invention.

6 is a timing chart for explaining the operation of the first embodiment of the present invention.

7 is a configuration diagram of a second embodiment of the linear sensor of the present invention.

8 is a timing chart for explaining the operation of the second embodiment of the present invention.

9 is a configuration diagram of a third embodiment of the linear sensor of the present invention.

10 is a block diagram of a modification of the present invention.

11 is a configuration diagram showing an example of color coding of each line in the linear sensor.

* Explanation of symbols for main parts of the drawings

1 ₀ ~ 1 ₃ : Sensor string 2 ₀ ~ 2 ₃ : CCD analog shift register for horizontal transmission

3 ₀ to 3 ₃ : Shift gate 4: CCD analog shift register for vertical transfer

5, 5 ₀ to 5 ₃ : Charge / voltage converter 6: Drive circuit

7: Sampling circuit SW1 ~ SW3: selector switch

The present invention relates to a solid state imaging device, and more particularly to a linear sensor having a plurality of sensor strings.

As the linear sensor, a linear sensor having a plurality of lines, for example, three lines formed on a chip, used in an image information input unit such as a color image scanner or a digital color copying machine is widely known. In this three-line linear sensor, it is more advantageous to derive the output signal of each line at one place than to derive the output signal at three places for each line in simplifying the signal processing system.

1 shows a conventional linear sensor. The conventional linear sensor has three sensor rows (1 ₁ ) to (1 ₃ ) arranged in the vertical direction (V direction), and each sensor row has a predetermined number of pixels arranged one-dimensionally in the horizontal direction (H direction). Has The analog shift registers (hereinafter referred to as HCCD) 2 ₁ to 2 ₃ are formed of a charge coupled device (CCD) that transfers signal charge in the H direction. The shift gates 3 ₁ to 3 ₃ are formed to shift the signal charges accumulated in the pixels of the sensor strings 1 ₁ to 1 ₃ to the HCCD 2 ₁ to 2 ₃ .

HCCD (2 ₁₎ ~ converted into a voltage by ₍₂₃₎ a signal for HCCD (2 ₁₎ ~ a charge / voltage of the floating diffusion amplifier disposed at the output side of ₍₂₃₎ converting unit such charge transfer by the ( Or reset). On the output side of the charge / voltage converting section 5 ₁ to 5 ₃ , switching switches SW1 to SW3 are arranged for each line, and these switching switches SW1 to SW3 are sequentially switched and controlled so that signals of each line are sequentially derived. It is supposed to be.

FIG. 2 shows the timing relationship between the horizontal transfer clocks? 1 and? 2 of the two phases shown in FIG. 1, the read pulses? Rog1 to? Rog3 and the output signal Vout of each of the shift gates 3 ₁ to 3 ₃ . The period t _int is the accumulation time of signal charges for each line.

As described above, in the conventional three-line linear sensor in which the output signal of each line is derived from one place, the output signal of each line by the switching switches SW1 to SW3 on the output side of the HCCD (2 ₁ ) to (2 ₃ ). In order to read out the output signal continuously, it is necessary to prevent the sampling time of the optical signal of each line from overlapping, and to sample three lines of image information at the same time in two dimensions. There was a flaw that we could not.

3 shows another conventional linear sensor. As shown in FIG. 3, a method of shielding the number of pixels to several tens of pixels at the end of each line so as to be optical black (OPB) and applying a black level correction clamp at the output of the OPB pixel portion is employed. .

4 shows the timing relationship between the two-phase horizontal transfer clocks? 1 and? 2, the read pulses? Rog1 to? Rog3 and the output signal Vout of each of the shift gates 3 ₁ to 3 ₃ shown in FIG. The period t _int is the accumulation time of signal charges for each line.

When the number of pixels in each line is large or when the transmission speed is slow, the dark current component in HCCD (2 ₁ ) to (2 ₃ ) becomes a problem, and the OPB in the horizontal direction is caused by this dark current component. The further away from the pixel portion, the lower the S / N of the pixel signal was.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object thereof is to provide an improved linear sensor that enables sampling of the same time for each image information of a plurality of lines.

It is also an object of the present invention to provide an improved linear sensor which makes it possible to improve the S / N of a pixel signal.

According to one aspect of the present invention, in the linear sensor for sampling the pixels corresponding to each other in the vertical direction of the plurality of sensor columns arranged in the vertical direction at about the same time, the plurality of sensor rows arranged in the vertical direction and the plurality of sensors arranged corresponding to the sensor rows are arranged. Horizontal transfer registers, a plurality of shift gates for transferring accumulated signal charges to a plurality of horizontal transfer registers, a vertical transfer register disposed on one side of the plurality of horizontal transfer registers, and an output side of the vertical transfer register. Provided is a linear sensor comprising a charge / voltage converter and a driving circuit for driving the plurality of shift gates, horizontal transfer registers, and vertical transfer registers.

According to another aspect of the present invention, there is provided a linear sensor characterized in that at least one line of sensor lines on the output side of the vertical transfer register among the plurality of sensor lines is optically shielded.

According to still another aspect of the present invention, in a linear sensor for sampling substantially vertically corresponding pixels of a plurality of sensor rows arranged in a vertical direction, a plurality of sensor rows arranged in a vertical direction and disposed in correspondence with these sensor rows are arranged. A plurality of horizontal transfer registers, a plurality of shift gates for transferring accumulated signal charges to a plurality of horizontal transfer registers, a plurality of charge / voltage converters disposed on the output side of each horizontal transfer register, a shift gate and a horizontal transfer register A linear sensor comprising a driving circuit for driving a circuit, at least one sensor string for optically shielding among a plurality of sensor strings, and a plurality of switch means disposed on an output side of each charge / voltage converting section.

According to the present invention, a vertical transfer register is disposed on one side of the plurality of horizontal transfer registers, and the signal charges accumulated in all pixels of the plurality of sensor trains are transferred to the plurality of horizontal transfer registers by the shift gate at the falling timing of the read pulse? ROG. Read and send to all at once. As a result, each pixel arranged in the vertical direction of the plurality of sensor columns can be sampled simultaneously, and image information of a plurality of lines can be sampled two-dimensionally at the same time.

Also, by providing the charge / voltage conversion section on the output side of the vertical transfer register, it is unnecessary to provide the charge / voltage conversion section for each line, and a single charge / voltage conversion section is shared for each line. Thereby, the nonuniformity of the signal level between lines resulting from the nonuniformity of the characteristic between a charge / voltage conversion part can be reduced.

Next, embodiments of the present invention will be described in detail with reference to FIGS. 5 to 11. In these figures, the same reference numerals are used for the same parts as in FIGS. 1 to 4.

5 is a configuration diagram showing a first embodiment of the linear sensor of the present invention. In the present embodiment, the sensor structure according to the present invention comprises a predetermined number of pixels arranged one-dimensionally in the horizontal direction (H direction), and only three lines arranged in the vertical direction (V direction). ₁ ) to (1 ₃ ), an analog shift register (hereinafter referred to as HCCD) (2 ₁ ) to (2 ₃ ) consisting of a CCD that transfers signal charge in the H direction, and a series of sensors (1 ₁ ) to (1 _It is composed of shift gates 3 ₁ to 3 _{3 which} transfer the signal charges accumulated in each pixel of ₃ ) to the HCCD 2 ₁ to 2 ₃ , respectively.

HCCD (2 ₁₎ to ₍₂₃₎ one HCCD side of the charge transfer direction ₍₂₁₎ - ₍₂₃₎ in the V direction the signal charge has been transferred in this order by transmitting analog vertical shift register (hereinafter, VCCD referred to 4) is excreted.

The signal charge transmitted by the VCCD 4 is converted (or reset) into a voltage by the charge / voltage converter 5 of the floating diffusion amplifier configuration disposed at the output side of the VCCD 4, for example. The output voltage of this charge / voltage conversion section 5 is derived externally as the sensor output Vout for three lines.

In addition, a drive circuit 6 including a timing generator (not shown) is provided to drive the HCCDs 2 ₁ to 2 ₃ , the shift gates 3 ₁ to 3 ₃ , and the VCCD 4. have. The driving circuit 6 shifts the horizontal transfer clocks øH1 and øH2 of plural phases (two phases in this example) to three columns of HCCD (2 ₁ ) to (2 ₃ ) in common. A common read gate pulse? ROG is supplied to the gates 3 ₁ to 3 ₃ , and a vertical transfer clock? V1 and? V2 of a plurality of phases (two phases in this example) are respectively supplied to the VCCD 4.

Here, the frequencies of the vertical transfer clocks? V1 and? V2 are set to be higher than the horizontal transfer clocks? H1 and? H2.

Next, the operation of the linear sensor of three lines having the above configuration will be described with reference to the timing chart of FIG.

First, the signal charge accumulated in each pixel of the _three sensor columns (1 ₁ ) to (1 ₃ ) is generated by the generation of the readout pulse øROG, and the shift timing (3 ₁ ) to (3 ₃ ) is applied to the HCCD ( 2 ₁ ) ~ (2 ₃ ) will be transmitted in unison. Thus, the signal charges of all the pixels for three lines are sampled at the same time in two dimensions.

When the simultaneous transfer of signal charges to the HCCD (2 ₁ ) to (2 ₃ ) is completed, the signal charge is horizontally transferred by the transmission drive of the HCCD (2 ₁ ) to (2 ₃ ) by the two-phase horizontal transfer clocks øH1 and øH2. Then, it is sequentially transmitted to the VCCD 4, and is then vertically transmitted by the transmission drive of the VCCD 4 by the two-phase vertical transmission clocks VV1 and VV2 of frequencies higher than the horizontal transmission clocks HH1 and HH2.

Then, by converting the voltage into the voltage in the charge / voltage conversion section 5, for example, as the output Vout, the signal of the pixel D _{1-1 at} the left end of the first line is first output, and then the second line is output. The signal of the pixel D _{2-1 at} the left end of the signal is output, followed by the signal of the pixel D _{3-1 at} the left end of the third line.

Subsequently, the signal of the second pixel D _1-2 from the left of the first line is output, followed by the signal of the second pixel D _2-2 from the left of the second line, and then The signal of the second pixel D _3-2 from the left of the third line is output to the.

Similarly, the signals of the pixels arranged in the vertical direction of each line are sequentially outputted.

7 is a configuration diagram showing a second embodiment of the linear sensor of the present invention. Compared to the linear sensor degrees foregoing claim 5, except that there was formed on the output side of the sensor column (1 _0), HCCD (2 _0), a shift gate ₍₃₀₎ the VCCD (4) In this embodiment, the other configuration Is the same. Thermal sensor ₍₁₀₎ has an optical configuration of a light-shielding black line or the like Al light-shielding film. The image signal of this black line is used for black level correction. In this example, only one line is formed as the black line, but a plurality of black lines may be formed.

As shown in FIG. 8, the vertical transfer charge is converted into a voltage by the charge / voltage converter 5 so as to output Vout, for example, a signal of the pixel B1 on the left side of the black line is first output, and then The signal of the pixel D _{1-1 at} the left end of the first line is output, followed by the signal of the pixel D _{2-1 at} the left end of the second line, and then the pixel of the left end of the third line. The signal of (D _3-1 ) is output.

Subsequently, the signal of the second pixel B2 from the left of the black line is output, the signal of the second pixel D _1-2 from the left of the first line is then output, and the signal of the second line is next. The signal of the second pixel D _2-2 from the left is output, and then the signal of the second pixel D _3-2 from the left of the third line is output.

Similarly, the signals of the pixels arranged in the vertical direction of each line are sequentially outputted.

Further, by disposing the optical sensor columns _(10), the light shielding by the output side of the VCCD (4), As is apparent from the waveform of the eighth-degree output Vout, prior to the output of the signal of the pixels arranged in the vertical direction of each line Since the black line signal is output, black level correction can be performed according to this black signal. When the black line signal is derived, each black signal is different from the dark current component due to the difference in the transmission time between the right side and the left side of the black line (the right side has a long transfer time, so the dark current component is large). By clamping the black signal, the black level correction can be made more accurate, and the S / N of the pixel signal can be improved. The black level correction clamp may be performed in the sensor value or externally.

9 is a configuration diagram showing a third embodiment of the linear sensor of the present invention. In this embodiment as in the case of the second embodiment, made of a pixel having a predetermined number arranged in the H direction in one dimension, V and direction by 4 lines delivery arrangement a sensor row ₍₁₀₎ - _(13), HCCD (2 ₀ ) to (2 ₃ ) which transmits the signal charge in the H direction, and the signal charge accumulated in each pixel of the sensor string (1 ₀ ) to (1 ₃ ) is HCCD (2 ₀ ) to (2 ₃ ) It has a sensor structure with shift gates (3 ₀ ) to (3 ₃ ), each of which is transmitted to the sensor.The four lines of sensor lines (1 ₀ ) to (1 ₃ ), for example, the top one line in the figure. the heat sensor ₍₁₀₎ is optically shaded constitute a black level correction black line.

In each line, HCCD (2 ₀₎ to ₍₂₃₎ to the signal charge HCCD (2 ₀₎ to the charge / voltage converter disposed in each output side of ₍₂₃₎ unit _(50), - transmission by ₍₅₃ Is converted into a voltage, and the signal of each line is sequentially derived as the output Vout by switching by the switching switches SW0 to SW3.

According to this configuration, since a black signal for one line can be derived, the black level correction is performed by clamping the black output for each pixel with the corresponding relationship of the pixels in the vertical direction between the lines after the output, thereby performing the second embodiment. As in the case of the example, even if there is a difference in the dark current component due to the difference in the transmission time in the horizontal direction, the black level correction can be performed more accurately, so that the S / N of the pixel signal can be improved.

In the present embodiment, only one black line is disposed, but a plurality of lines may be disposed as the black line, and the black line is arranged at the top of FIG. 9, but the arrangement is 3 to obtain pixel information. It may be a position between lines. However, the output of the black signal is a reference for the black level correction, so it is necessary to switch control the switch switches SW0 to SW3 to output before the output of the other three lines.

According to the above configuration, as is apparent from the waveforms of the output Vout in Figs. 6 and 8, the pixel signals of each line are alternately output.

As shown in FIG. 10, a sampling circuit 7 is provided as an external circuit. In this sampling circuit 7, the output Vout is sampled at a predetermined timing, and the pixel signals are rearranged for each line to produce a television signal. It is also possible to easily convert.

In addition, the linear sensor the color linear sensor, and the third column sensor columns of the present invention (1 ₁₎ to _(13), the three primary colors (R, G, B) are dot-sequential, as shown in claim 11, respectively ( By having the color coding arranged so that the same color is arranged in the V direction in each sensor column, it is possible to derive the pixel signals of the same color for three lines as the output Vout.

While particular embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the invention.

Claims (18)

A linear sensor for sampling substantially vertically corresponding pixels of a plurality of sensor columns arranged in a vertical direction, the linear sensor comprising a predetermined number of pixels arranged in one dimension in a horizontal direction and a plurality of lines arranged in a plurality of lines in a vertical direction. A plurality of horizontal transfer registers disposed corresponding to the plurality of sensor sequences and transmitting signal charges in the horizontal direction, and signal charges accumulated in each pixel of the plurality of sensor sequences to the plurality of horizontal transfer registers at substantially the same time. A plurality of shift gates, a vertical transfer register disposed at one end of the plurality of horizontal transfer registers for sequentially transferring signal charges by the transfer of the plurality of horizontal transfer registers in a vertical direction, and an output side of the vertical transfer register. A charge / voltage conversion section disposed, the plurality of shift gates, the horizontal transfer register, and a phase And a driving circuit for driving a vertical transfer register, wherein the signal charge accumulated in a vertically corresponding pixel of the plurality of sensor columns arranged in the vertical direction is sequentially and repeatedly transmitted to the charge / voltage conversion unit. sensor. The linear sensor according to claim 1, wherein the sensor string, the horizontal transfer register and the shift register are arranged in three lines, respectively. The linear sensor according to claim 1, wherein each of the plurality of sensor lines is arranged in a dot sequence of three primary colors. The linear sensor according to claim 1, wherein the output of the charge / voltage conversion unit is sampled to generate a television signal for the plurality of sensor strings. The linear sensor as claimed in claim 1, wherein the plurality of shift gates simultaneously read and transmit signal charges accumulated in all pixels of the plurality of sensor strings to the plurality of horizontal transfer registers. The linear sensor as claimed in claim 1, wherein the frequency of the drive clock of the vertical transfer register is higher than the frequency of the drive clock of the horizontal transfer register. A linear sensor for sampling substantially vertically corresponding pixels of a plurality of sensor columns arranged in a vertical direction, the linear sensor comprising a predetermined number of pixels arranged in one dimension in a horizontal direction and a plurality of lines arranged in a plurality of lines in a vertical direction. A plurality of horizontal transfer registers disposed corresponding to the plurality of sensor sequences and transmitting signal charges in the horizontal direction, and signal charges accumulated in each pixel of the plurality of sensor sequences to the plurality of horizontal transfer registers at substantially the same time. A plurality of shift gates, a vertical transfer register disposed at one end of the plurality of horizontal transfer registers to sequentially transfer signal charges due to the transfer of the plurality of horizontal transfer registers in a vertical direction, and an output side of the vertical transfer register. A charge / voltage conversion section disposed, the plurality of shift gates, the horizontal transfer register, and a phase And a driving circuit for driving the vertical transfer register, wherein at least one line of the sensor train on the output side of the vertical transfer register in the plurality of sensor trains is optically shielded, and the plurality of sensor trains arranged in the vertical direction. And the signal charge accumulated in the vertically corresponding pixel is sequentially and repeatedly transmitted to the charge / voltage converter. 8. The linear sensor according to claim 7, wherein the sensor string, the horizontal transfer register, and the shift register are arranged in four lines, respectively. 8. The linear sensor according to claim 7, wherein the plurality of sensor strings except for at least one optically shielded sensor string are arranged in a sequential order in three primary colors. 8. The linear sensor according to claim 7, wherein the output of the charge / voltage conversion section is sampled to generate television signals for the plurality of sensor strings. 8. The linear sensor as claimed in claim 7, wherein the plurality of shift gates simultaneously read and transmit signal charges accumulated in all pixels of the plurality of sensor strings to the plurality of horizontal transfer registers. 8. The linear sensor as claimed in claim 7, wherein the frequency of the drive clock of the vertical transfer register is higher than the frequency of the drive clock of the horizontal transfer register. A linear sensor for sampling substantially vertically corresponding pixels of a plurality of sensor columns arranged in a vertical direction, the linear sensor comprising a predetermined number of pixels arranged in one dimension in a horizontal direction and a plurality of lines arranged in a plurality of lines in a vertical direction. A plurality of horizontal transfer registers disposed corresponding to the plurality of sensor sequences and transmitting signal charges in the horizontal direction, and signal charges accumulated in each pixel of the plurality of sensor sequences to the plurality of horizontal transfer registers at substantially the same time. A plurality of shift gates, a plurality of charge / voltage converters disposed on an output side of the horizontal transfer register, a driving circuit for driving the plurality of shift gates, the horizontal transfer register and the vertical transfer register, At least one line of sensor light that is optically shielded among the sensor trains, and the output side of each charge / voltage conversion unit. Is disposed, linear sensor which comprises a plurality of said switching means said signal charges stored in the pixels corresponding to the vertical in a vertical column, a plurality of sensors arranged in a direction that is controlled to sequentially output repeatedly. 14. The linear sensor according to claim 13, wherein said switch means is controlled so that said signal charge of at least one line of optically shielded sensor string is output before signal charge is output from another line. The linear sensor according to claim 13, wherein the sensor string, the horizontal transfer register and the shift register are arranged in four lines each. 14. The linear sensor according to claim 13, wherein the plurality of sensor strings except for the optically shielded at least one line of sensor lines are arranged in a sequential order in three primary colors. The linear sensor according to claim 13, wherein the output of the charge / voltage conversion unit is sampled to generate a television signal for the plurality of sensor strings. The linear sensor according to claim 13, wherein the plurality of shift gates simultaneously read and transmit signal charges accumulated in all pixels of the plurality of sensor strings to the plurality of horizontal transfer registers.