JP2009022040A - Linear image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear image sensor capable of performing photography of high optical resolution and high sensitivity, without requiring a high-precision mechanical mechanism. <P>SOLUTION: The linear image sensor includes red diode arrays 11a and 11b, green diode arrays 12a and 12b, and blue diode arrays 13a and 13b, the diode arrays 11b, 12b, and 13b disposed shifting from the diode arrays 11a, 12a, and 13b in the array direction, by about a half as large as an interval in a photodiode array direction; charge transfer channels 21c, 22c, and 23c for transferring signal charges detected by photodiodes are formed between the red diode arrays 11a and 11b, green diode arrays 12a and 12b, and blue diode arrays 13a and 13b, respectively, to form a meandering shape that extends in the main scanning direction. Signal charges read out to the charge transfer channels 21c, 22c, and 23c are transferred in the main scanning direction, and output from output terminals OUT31c, OUT32c, and OUT33c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear image sensor including a photoelectric conversion element array in which photoelectric conversion elements are linearly arranged on a semiconductor substrate, and more particularly to a linear image sensor suitable for color photography including a plurality of photoelectric conversion element arrays.

  A linear image sensor used in various devices such as a facsimile, an electronic copying machine, an image scanner, and a barcode reader has an imaging unit formed on a semiconductor substrate. The imaging unit includes a photoelectric conversion element array in which photoelectric conversion elements such as photodiodes are arranged substantially linearly, and a charge transfer unit formed in the vicinity of the photoelectric conversion element array. The charge transfer unit includes a charge transfer channel for transferring a signal charge detected by the photoelectric conversion element, and a plurality of charge transfer electrodes for controlling the signal charge transfer. The signal charge transferred by the charge transfer unit is sent to an output unit such as a floating diffusion amplifier and output as a voltage signal.

  A linear image sensor for color image capturing has red, green, and blue color filters formed on each photoelectric conversion element, and each photoelectric conversion element has signal charges corresponding to red light, green light, and blue light, respectively. To detect.

  FIG. 21 shows a schematic configuration of an example of an imaging unit of a conventional linear image sensor for color image imaging. The linear image sensor of FIG. 21 has three rows of photodiode rows 511, 512, and 513 in which substantially rectangular photodiodes 500 are arranged in a straight line. The photodiode rows 511, 512, and 513 include a charge transfer unit 521. 522 and 523 are juxtaposed. Output portions 531, 532, and 533 including floating diffusion amplifiers are formed at one ends of the charge transfer portions 521, 522, and 523, and correspond to signal charges detected by the photodiode 500 from the output terminals 541, 542, and 543. Output voltage.

  The photodiode rows 511, 512, and 513 output signals corresponding to red light, green light, and blue light, respectively. That is, a red filter (not shown) is formed for each photodiode forming the photodiode array 511, and a green filter (not shown) is formed for each photodiode forming the photodiode array 512, and the photodiode. A blue filter (not shown) is formed on each photodiode forming the column 513.

  Accordingly, since the signals as shown in FIG. 22A are output from the output terminals 541, 542, and 543, after performing AD conversion and other processing, color imaging as shown in FIG. 22B is performed. It can be used as a signal. 22, Rn, G1, G2,..., Gn, B1, B2,..., Bn are the same as R1, R2,..., Rn, G1, G2,. This shows a signal detected by a photodiode provided with Gn, B1, B2,..., Bn, and the same applies to the following description.

  However, in the linear image sensor of FIG. 21, since it is necessary to provide the charge transfer units 521 and 522 between the photodiode rows 511 and 512 and between the 512 and 513, between the photodiode rows 511, 512, and 513. The interval cannot be reduced. Therefore, in order to perform high-resolution imaging, the direction (hereinafter simply referred to as the sub-scanning direction) intersecting the arrangement direction of the photodiode rows 511, 512, and 513 (hereinafter sometimes simply referred to as the main scanning direction). Position accuracy is required). The accuracy in the sub-scanning direction depends on the mechanical accuracy of the sub-scanning mechanism, and it is generally difficult to obtain a highly accurate mechanism at low cost.

  FIG. 23 is a diagram illustrating a schematic configuration of another example of an imaging unit of a conventional linear image sensor for imaging a color image. The linear image sensor of FIG. 23 has two rows of photodiode rows 611 and 612 in which substantially rectangular photodiodes 600 are arranged in a straight line. The photodiode rows 611 and 612 are provided close to each other, and the charge transfer units 621 and 622 are provided outside the photodiode rows 611 and 612. In addition, output units 631 and 632 including floating diffusion amplifiers and the like are formed at one ends of the charge transfer units 621 and 622, and voltages corresponding to the signal charges detected by the photodiode 600 are output from the output terminals 641 and 642, respectively. .

  A red filter and a blue filter (not shown) are alternately formed on each photodiode forming the photodiode row 611, and a green filter (not shown) is formed on each photodiode forming the photodiode row 612. The

  Therefore, since the signals as shown in FIG. 24A are output from the output terminals 641 and 642, after performing AD conversion and other processing, the calculation of the color signal is performed and the signals shown in FIG. It can be used as a color imaging signal as shown.

  In the linear image sensor of FIG. 23, since the photodiode arrays 611 and 612 are provided close to each other, the mechanical accuracy of the sub-scanning mechanism is not necessarily required. However, it is difficult to improve the detection sensitivity because the number of photodiode rows cannot be more than two. That is, if the number of photodiode rows is increased to increase detection sensitivity, the charge transfer unit is arranged in the photodiode row, and the resolution deteriorates.

  The present invention has been made in view of the above circumstances, and provides a linear image sensor capable of photographing with high optical resolution and high sensitivity without requiring a high-precision mechanical mechanism.

  The linear image sensor of the present invention includes a plurality of photoelectric conversion element arrays in which a plurality of photoelectric conversion elements are linearly arranged on a semiconductor substrate, and includes a charge transfer unit that transfers charges from the photoelectric conversion elements; And an output unit that outputs a signal corresponding to the charge transferred by the charge transfer unit, and the photoelectric conversion elements included in the adjacent photoelectric conversion element arrays are mutually connected within the photoelectric conversion element array. The photoelectric transfer elements are arranged approximately ½ of the pitch between the photoelectric conversion elements and shifted in the column direction, and the charge transfer unit is configured to transfer charges formed on the semiconductor substrate corresponding to each column of the photoelectric conversion element columns. A channel and a plurality of charge transfer electrodes formed so as to intersect each of the charge transfer channels in plan view, and the charge transfer channel as a whole extends in the direction of the photoelectric conversion element array Present Thus, the photoelectric conversion elements are formed close to each other, and each of the photoelectric conversion element arrays includes photoelectric conversion elements that detect charges corresponding to specific monochromatic light, and corresponds to the same monochromatic light. The charge transfer unit is provided adjacent to the even number columns, and the charge transfer unit is provided between the two adjacent columns as the two adjacent columns of the photoelectric conversion element columns corresponding to the same monochromatic light. Is. If comprised in this way, the gap between photoelectric conversion element rows can be made small, and the detection accuracy in the sub-scanning direction substantially orthogonal to the row direction as a whole can be improved. Therefore, even if the allowable range of mechanical sub-scanning accuracy is widened, high-accuracy imaging can be performed. In addition, the resolution in the main scanning direction can be improved and the detection sensitivity can be increased, and the added signal charge can be read out, so that the detection sensitivity can be increased with a simpler configuration.

  In the linear image sensor of the present invention, the charge transfer electrodes are formed between the photoelectric conversion elements so as to exhibit a meandering shape extending in a direction intersecting with the photoelectric conversion element array direction as a whole. . Thus, the transfer electrodes corresponding to the photoelectric conversion elements of the plurality of photoelectric conversion element arrays can be formed as a single body, and the transfer pulse supply wiring for the transfer electrodes can be easily formed.

  In the linear image sensor of the present invention, four charge transfer electrodes are provided corresponding to the photoelectric conversion elements.

  Moreover, the monochromatic light in the linear image sensor of the present invention is three types of red light, green light, and blue light.

  As apparent from the above description, according to the present invention, it is possible to provide a linear image sensor capable of photographing with high resolution and high sensitivity without requiring a high-precision mechanical mechanism.

  Embodiments of the present invention will be described with reference to FIGS.

(First embodiment)
FIG. 1 shows a schematic configuration of a part of an imaging unit of the linear image sensor according to the first embodiment. The linear image sensor shown in FIG. 1 includes red light detection photodiodes R1, R2,..., Rn−1, Rn (red diode line 11), and green light detection photodiodes G1, G2, respectively. ,..., Gn-1, Gn (green diode row 12), blue light detection photodiodes B1, B2,..., Bn-1, Bn (blue diode row 13). As shown in the drawing, the green diode row 12 positioned between the red diode row 11 and the blue diode row 13 is disposed so as to be shifted in the column direction by about ½ of the pitch in the photodiode row direction.

  The charge transfer channels 21, 22, and 23 constituting the charge transfer unit for transferring the signal charges detected by the photodiodes R1 to Rn, G1 to Gn, and B1 to Bn are a red diode row 11 and a green diode row 12 respectively. , Formed in the vicinity of the blue diode row 13 and has a meandering shape extending in the main scanning direction. Signal charges read from the photodiodes R1 to Rn, G1 to Gn, and B1 to Bn to the charge transfer channels 21, 22, and 23 at a predetermined timing are shifted to a charge transfer electrode (not shown in FIG. 1) by a predetermined shift. By supplying a pulse, the signal is transferred in the main scanning direction and output from the output terminals OUT31, OUT32, and OUT33.

  Before describing the processing of imaging signals output from the output terminals OUT31, OUT32, and OUT33, a more detailed configuration of the charge transfer unit, readout of signal charges to the charge transfer channel, and mechanism of charge transfer to the output terminal Will be described. FIG. 4 shows the imaging unit of the linear image sensor of FIG. 1 in more detail, and shows charge transfer electrodes on the charge transfer channels 21, 22, and 23. Four charge transfer electrodes H1, H2, H3, and H4 are provided corresponding to one photodiode, and each is driven at a timing shifted by a quarter cycle.

  In FIG. 4, the charge transfer electrodes H1 to H4 are schematically shown as single elements corresponding to the respective photodiodes of the charge transfer channels 21, 22, and 23. Specifically, FIG. As shown, the common conductor is used. In FIG. 5, channel stop regions 51, 52, 53, and 54 that separate the diode arrays 11, 12, and 13 of the respective colors are formed on the semiconductor substrate on which the photodiodes are formed, and between the channel stop regions 51 and 52. In the charge transfer channel 21, the charge transfer channel 22 is formed between the channel stop regions 52 and 53, and the charge transfer channel 23 is formed between the channel stop regions 53 and 54, respectively. The charge transfer electrodes H1 to H4 are formed between the photodiodes so as to exhibit a meandering shape extending in a direction crossing the main scanning direction as a whole.

  As shown schematically by arrows in FIG. 4 and FIG. 5, the readout gate portion that reads the signal charges from the photodiode to the charge transfer channel is the bottom of the charge transfer electrode H4 in the red diode row 11 and the blue diode row 13. It is formed between the charge transfer channels 21 and 23, and in the green diode row 12, it is formed between the charge transfer channels 22 below the charge transfer electrode H2. The readout gate electrode is also used as the charge transfer electrodes H4 and H2, and by supplying a readout pulse having a higher potential than the shift pulse to the charge transfer electrodes H4 and H2, the signal charge accumulated in the photodiode is transferred to the charge transfer channel 21, 22 and 23 are read out.

  Next, a signal charge reading operation and a charge transfer operation from the photodiode will be described with reference to a time chart of FIG. As shown in FIG. 6, a four-phase shift pulse shifted by a quarter cycle is applied to the charge transfer electrodes H1 to H4, and the signal charges held in the charge transfer channel below each electrode are sequentially subjected to main scanning. Forwarded in the direction.

  At time t1, when the read pulse is superimposed on the shift pulse H4, the signal charges of the photodiodes R1 to Rn and B1 to Bn are read to the charge transfer channels 21 and 23, respectively, via the read gate. At time t2, when the readout pulse is superimposed on the shift pulse H2, the signal charges of the photodiodes G1 to Gn are read out to the charge transfer channel 22 via the readout gate.

  The signal charges read to the charge transfer channels 21, 22, and 23 are sequentially transferred according to the shift pulse, and the signal charge of the photodiode R1 is output from the output terminal OUT31 at time t3, and the photodiode R2 at time t4. The signal charges are sequentially output in synchronization with the shift pulse. Similarly, the signal charge of the photodiode B1 is output from the output terminal OUT33 at time t3 and sequentially output. Further, the signal charge of the photodiode G1 is output from the output terminal OUT32 at time t4, and the signal charge of the photodiode G2 at time t5 is sequentially delayed by one cycle with respect to the output terminal OUT31 and the output terminal OUT33. Is output.

  Therefore, the signal charges output from the output terminals OUT31 to OUT33 correspond to the color signals at the detection positions as shown in FIG. These signal charges are converted into voltage signals at an output section (not shown) and output as color signals for each photodiode.

  When it is used as a color image signal, as is clear from FIG. 2, the green (G) signal is shifted by about ½ pitch, so that correction processing is performed to obtain a red (R) signal as shown in FIG. A green (G) signal and a blue (B) signal are assumed. FIG. 3A shows a correction based on the position of the green diode row 12, and the R signal and the B signal are average values of the outputs of two adjacent diodes. FIG. 3 (b) is a correction based on the positions of the red diode row 11 and the blue diode row 13, and the G signal is the average value of the outputs of two adjacent diodes. Although the correction processing here is performed outside the linear image sensor, the method is not limited to the method described here, and other methods may be used.

  As described above, in the linear image sensor according to the first embodiment, a plurality of adjacent diode rows are arranged so as to be shifted from each other by about 1/2 pitch of the photodiode interval, and the charge transfer channel is arranged as a whole. Since the arrangement is such that the meandering shape extends in the photodiode column direction, the interval between columns is not widened even if a photodiode column for detecting RGB color signals is provided.

(Second Embodiment)
FIG. 7 shows a schematic configuration of a part of the imaging unit of the linear image sensor according to the second embodiment. In the linear image sensor of FIG. 7, photodiodes for detecting red light, photodiodes for detecting green light, and photodiodes for detecting blue light are arranged in two rows.

  Red light detection photodiodes R1a, R2a,..., Rn-1a, Rna arranged in a row and red light detection photodiodes R1b, R2b,..., Rn-1b, Rnb in a row. The arranged red diode rows 11b are arranged adjacent to each other and shifted in the row direction by about ½ of the pitch in the photodiode row direction. Similarly, green light detection photodiodes G1a, G2a,..., Gn-1a, Gna arranged in a row, and green light detection photodiodes G1b, G2b,..., Gn-1b, Gnb , Bn-1a, Bna are arranged in a row, and blue light detection photodiodes B1b, B2b are arranged in a row. ,..., Bn-1b and Bnb are arranged in a row, and the blue diode row 13b is also arranged adjacently and shifted in the row direction by about ½ of the pitch in the photodiode row direction. Further, the red diode row 11b and the green diode row 12a, and the green diode row 12b and the blue diode row 13a are also arranged so as to be shifted in the column direction by about ½ of the pitch in the photodiode column direction.

  Charge transfer channels 21a, 21b, 22a constituting charge transfer units for transferring signal charges detected by the photodiodes R1a to Rna, R1b to Rnb, G1a to Gna, G1b to Gnb, B1a to Bna, B1b to Bnb , 22b, 23a, and 23b are formed close to the red diode rows 11a and 11b, the green diode rows 12a and 12b, and the blue diode rows 13a and 13b, respectively, and have meandering shapes extending in the main scanning direction. At predetermined timing, the data are read from the photodiodes R1a to Rna, R1b to Rnb, G1a to Gna, G1b to Gnb, B1a to Bna, B1b to Bnb to the charge transfer channels 21a, 21b, 22a, 22b, 23a, and 23b. The signal charge is transferred in the main scanning direction by supplying a predetermined shift pulse to a charge transfer electrode (not shown in FIG. 7), and is output from the output terminals OUT31a, OUT31b, OUT32a, OUT32b, OUT33a, and OUT33b.

  The charge transfer electrodes (not shown) on the charge transfer channels 21a, 21b, 22a, 22b, 23a, and 23b are provided with a single photodiode as in the linear image sensor of the first embodiment shown in FIGS. Corresponding to the four charge transfer electrodes H1, H2, H3, and H4, which are driven at a timing shifted by a quarter cycle. Further, the charge transfer electrodes H1 to H4 are formed between the photodiodes so as to exhibit a meandering shape extending in a direction crossing the main scanning direction as a whole. Further, the readout gate portion for reading the signal charges from the photodiode to the charge transfer channel is also formed at the same position as the linear image sensor of the first embodiment.

  Therefore, when the same shift pulse and readout pulse as those of the linear image sensor of the first embodiment are applied to the charge transfer electrodes H1 to H4, the signal charges output from the output terminals OUT31a to OUT33b are as shown in FIG. It corresponds to each color signal of the correct detection position. These signal charges are converted into voltage signals at an output section (not shown) and output as color signals for each photodiode.

  As is apparent from FIG. 8, the R, G, and B signals from the output terminals OUT31b, OUT32b, and OUT33b are about 1 / R with respect to the R, G, and B signals from the output terminals OUT31a, OUT32a, and OUT33a. As shown in FIG. 9, when (R1a, G1a, B1a), (R1b, G1b, B1b), (R2a, G2a, B2a),... Are used as color image signals, as shown in FIG. The resolution can be made twice the arrangement pitch of the photodiodes.

  Further, outside the linear image sensor, as shown in FIG. 10, the R signal from the output terminals OUT31a and OUT31b, the G signal from the output terminals OUT32a and OUT32b, and the B signal from the output terminals OUT33a and OUT33b are added. It can also be used as a color image signal. When used in this way, the resolution in the main scanning direction is the same as the arrangement pitch of the photodiodes, but the sensitivity can be doubled.

  The linear image sensor of FIG. 7 has charge transfer channels 21a and 21b adjacent to the red diode rows 11a and 11b, charge transfer channels 22a and 22b close to the green diode rows 12a and 12b, and charges close to the blue diode rows 13a and 13b. The transfer channels 23a and 23b are connected to different output terminals OUT31a, OUT31b, OUT32a, OUT32b, OUT33a and OUT33b, respectively, but the charge transfer channels 21a and 21b, the charge transfer channels 22a and 22b, and the charge transfer channels 23a and 23b are connected. Each of them may be one output terminal. In this case, the number of shift stages from the red diode row 11b, the green diode row 12b, and the blue diode row 13b is omitted for ½ period before the output end.

  With such a configuration, the color signals as shown in FIG. 9 are output from the respective output terminals, so that the resolution can be used as a color image signal having twice the arrangement pitch of the photodiodes.

(Third embodiment)
FIG. 11 shows a schematic configuration of a part of the imaging unit of the linear image sensor according to the third embodiment. The linear image sensor shown in FIG. 11 includes two red diode rows 11a and 11b, two green diode rows 12a and 12b, and two blue diode rows 13a and 13b. This is the same as the second embodiment.

  The difference from the second embodiment is the configuration of the charge transfer channel. In the linear image sensor of FIG. 11, the charge transfer channel 21c for transferring the signal charges of the two red diode rows 11a and 11b, and the two rows The charge transfer channel 22c for transferring the signal charges of the green diode rows 12a and 12b, and the charge transfer channel 23c for transferring the signal charges of the two blue diode rows 13a and 13b are respectively connected between the red diode rows 11a and 11b. The green diode rows 12a and 12b and the blue diode rows 13a and 13b are provided.

  The position of the charge readout gate is also different. In the linear image sensor of FIG. 11, as indicated by arrows in FIG. 13, the red diode row 11a, the green diode row 12a, and the blue diode row 13a are connected to the charge transfer channels 21c, 22c, and 23c below the charge transfer electrode H4. The red diode row 11b, the green diode row 12b, and the blue diode row 13b are formed between the charge transfer channels 21c, 22c, and 23c below the charge transfer electrode H1.

  As shown in FIG. 13, a charge transfer channel 21c is formed between channel stop regions 55 and 56 formed in the semiconductor substrate on which the photodiode is formed, and the charge readout channels of the photodiodes R1a, R2a, and R3a are charged. The charge readout channels of the photodiodes R1b, R2b, and R3b are formed between the charge transfer electrode H1 and the transfer electrode H4. Similarly to the first embodiment (see FIG. 5), the charge transfer electrodes H1 to H4 are formed between the photodiodes so as to exhibit a meandering shape extending in a direction crossing the main scanning direction as a whole. .

  Since the charge readout channel is provided at a position corresponding to the charge transfer electrodes H4 and H1, the readout pulse having a higher potential than the shift pulse is shifted to the shift pulses H1 and H4 at time t11 and time t12, respectively, as shown in FIG. Superimposed. When such driving is performed, a charge obtained by adding the signal charge of the photodiode R1a and the signal charge of R1b is output from the output terminal OUT31c, and subsequently, a charge obtained by adding the signal charge of the photodiode R2a and the signal charge of R2b. In this way, it is output sequentially.

  Therefore, the signal charges output from the output terminals OUT31c to OUT33c correspond to the color signals at the detection positions as shown in FIG. These signal charges are converted into voltage signals at an output section (not shown) and output as color signals for each photodiode. As can be seen from FIG. 12, the linear image sensor of FIG. 11 can output a signal similar to the color image signal shown in FIG. Sensitivity can be imaged. In addition, since the addition of signals is performed using signal charges, the number of output units can be reduced, and the amount of signal processing can be greatly reduced.

(Fourth embodiment)
In the above embodiment, photodiodes for detecting the same color light are arranged in one row. However, the linear image sensor of the fourth embodiment includes photodiodes for detecting light of different colors in the same column. Composed. FIG. 15 shows a schematic configuration of a part of the imaging unit of the linear image sensor according to the fourth embodiment. The linear image sensor of FIG. 15 is a red / blue diode array in which red light detection photodiodes R1, R2,..., Rn and blue light detection photodiodes B1, B2,. 211 and a green diode row 212 in which photodiodes G1, G2,..., G2n-1 and G2n for detecting green light are arranged in a row. As shown in the figure, the green diode row 212 is arranged so as to be shifted in the row direction by about ½ of the pitch in the photodiode row direction with respect to the red / blue diode row 211.

  The charge transfer channel 221 constituting the charge transfer unit for transferring the signal charges detected by the photodiodes R1 to Rn and B1 to Bn is formed close to the red / blue diode row 211, and the photodiodes G1 to G2n The charge transfer channel 222 that constitutes a charge transfer unit for transferring the signal charge detected by the above is formed close to the green diode row 212. As in the other embodiments, the charge transfer channels 221 and 222 have a meandering shape extending in the main scanning direction.

  The signal charges read from the photodiodes R1 to Rn, B1 to Bn, and G1 to G2n to the charge transfer channels 221 and 222 are mainly supplied by supplying a predetermined shift pulse to charge transfer electrodes not shown in FIG. It is transferred in the scanning direction and output from the output terminals OUT231 and OUT232.

  The charge transfer electrodes (not shown) on the charge transfer channels 221 and 222 have four charge transfers corresponding to one photodiode as in the linear image sensor of the first embodiment shown in FIGS. Electrodes H1, H2, H3, and H4 are provided, and are driven at a timing shifted by a quarter cycle. Further, the charge transfer electrodes H1 to H4 are formed between the photodiodes so as to exhibit a meandering shape extending in a direction crossing the main scanning direction as a whole. Further, the readout gate portion for reading the signal charges from the photodiode to the charge transfer channel is also formed at the same position as the linear image sensor of the first embodiment.

  Therefore, when the same shift pulse and readout pulse as those of the linear image sensor of the first embodiment are applied to the charge transfer electrodes H1 to H4, the signal charges output from the output terminals OUT231 and 232 are as shown in FIG. It corresponds to each color signal of the correct detection position. These signal charges are converted into voltage signals at an output section (not shown) and output as color signals for each photodiode.

  When used as a color image signal, RGB three-color signals are required, so the color signal of the undetected portion is obtained by interpolation as shown in FIG. Further, as is clear from FIG. 17, since the G signal is shifted by about ½ pitch with respect to the R signal and the B signal, correction processing is further performed to obtain an RGB signal as shown in FIG. Such image signal processing is performed outside the linear image sensor. Further, the processing method is not limited to this method.

(Fifth embodiment)
FIG. 18 illustrates a schematic configuration of a part of the imaging unit of the linear image sensor according to the fifth embodiment. The linear image sensor of FIG. 18 includes a red / blue diode row and a green diode row as in the linear image sensor of the fourth embodiment, but differs from the fourth embodiment in that a plurality of rows are provided.

  The red / blue diode array is a red / blue diode in which red light detection photodiodes R1a, R3a,..., Rn-1a and blue light detection photodiodes B2a, B4a,. .., Bn-1b and red light detection photodiodes R2b, R4b,..., Rnb alternately arranged in one row, red / blue diode row 211b, red , Rn-1c and blue light detection photodiodes B2c, B4c,..., Bnc are alternately arranged in one row, and the red / blue diode row 211c is included. The diode array 211b differs from the red / blue diode arrays 211a and 211c in the arrangement order of the diodes.

  The green diode array includes green light detection photodiodes G1a, G2a,..., G2n-1a, G2na arranged in a line, and green light detection photodiodes G1b, G2b,. , G2nb are arranged in a row, and a green diode row 212b is included. The green diode row 212a is disposed between the red / blue diode rows 211a and 211b, and the green diode row 212b is disposed between the red / blue diode rows 211b and 211c. Further, the green diode rows 212a and 212b are arranged so as to be shifted in the column direction by about ½ of the pitch in the photodiode row direction with respect to the red / blue diode rows 211a, 211b, and 211c.

  Transfers signal charges detected by the photodiodes R1a to Rna and B1a to Bna, the photodiodes R1b to Rnb and B1b to Bnb, the photodiodes R1c to Rnc and B1a to Bnc, the photodiodes G1a to Gna, and the photodiodes G1b to Gnb Charge transfer channels 221a, 221b, 221c, 222a, and 222b that constitute a charge transfer unit for forming the red and blue diode rows 211a, 211b, and 211c and the green diode rows 212a and 212b, respectively, in the main scanning direction It has a meandering shape extending to At predetermined timing, photodiodes R1a to Rna and B1a to Bna, photodiodes R1b to Rnb and B1b to Bnb, photodiodes R1c to Rnc and B1a to Bnc, photodiodes G1a to Gna, photodiodes G1b to Gnb, and charge transfer channels The signal charges read to 221a, 221b, 221c, 222a, 222b are transferred in the main scanning direction by supplying a predetermined shift pulse to a charge transfer electrode (not shown in FIG. 18), and output terminals OUT231a, OUT231b. , OUT231c, OUT232a, and OUT232b.

  Charge transfer electrodes (not shown) on the charge transfer channels 221a, 221b, 221c, 222a, and 222b correspond to one photodiode as in the linear image sensor of the first embodiment shown in FIGS. Thus, four charge transfer electrodes H1, H2, H3, and H4 are provided, and driven at a timing shifted by a quarter cycle. Further, the charge transfer electrodes H1 to H4 are formed between the photodiodes so as to exhibit a meandering shape extending in a direction crossing the main scanning direction as a whole. Further, the readout gate portion for reading the signal charges from the photodiode to the charge transfer channel is also formed at the same position as the linear image sensor of the first embodiment.

  Therefore, when the same shift pulse and readout pulse as those of the linear image sensor of the first embodiment are applied to the charge transfer electrodes H1 to H4, the signal charges output from the output terminals OUT231a, OUT231b, OUT231c, OUT232a, and OUT232b are This corresponds to each color signal at the detection position as shown in FIG. These signal charges are converted into voltage signals at an output section (not shown) and output as color signals for each photodiode.

  When used as a color image signal, a signal subjected to addition calculation as shown in FIG. 20 is used as a detected color signal. As apparent from FIG. 20, since the G signal is shifted by about ½ pitch with respect to the R signal and the B signal, correction processing is further performed to obtain an RGB signal as shown in FIG. Such image signal processing is performed outside the linear image sensor. Further, the processing method is not limited to this method.

  Since the linear image sensor of the fifth embodiment uses a signal obtained by adding signal charges of a plurality of photodiodes as a detection color signal, the detection sensitivity can be increased. When compared with the third and fourth embodiments, the sensitivity can be increased by reducing the number of columns. In addition, since the positions of the photodiodes to be added are dispersed, unnatural color signals caused by signal addition can be avoided.

The figure which shows schematic structure of a part of imaging part of the linear image sensor of 1st Embodiment. The figure which shows the output color signal by the linear image sensor of 1st Embodiment The figure which shows the color image signal calculated from the output color signal by the linear image sensor of 1st Embodiment The figure which shows a part of imaging part of the linear image sensor of 1st Embodiment further in detail. The figure which shows the structural example of the charge transfer electrode of the linear image sensor of 1st Embodiment. A time chart showing a read operation and a charge transfer operation of the linear image sensor of the first embodiment The figure which shows schematic structure of a part of imaging part of the linear image sensor of 2nd Embodiment. The figure which shows the output color signal by the linear image sensor of 2nd Embodiment The figure which shows an example of the color image signal calculated from the output color signal by the linear image sensor of 2nd Embodiment The figure which shows the other example of the color image signal calculated from the output color signal by the linear image sensor of 2nd Embodiment. The figure which shows schematic structure of a part of imaging part of the linear image sensor of 3rd Embodiment. The figure which shows the output color signal by the linear image sensor of 3rd Embodiment The figure which shows a part of imaging part of the linear image sensor of 3rd Embodiment in detail Time chart showing read operation and charge transfer operation of linear image sensor of third embodiment The figure which shows a part of imaging part of the linear image sensor of 4th Embodiment in detail The figure which shows the output color signal by the linear image sensor of 4th Embodiment The figure which shows an example of the color image signal calculated from the output color signal by the linear image sensor of 4th Embodiment The figure which shows a part of imaging part of the linear image sensor of 5th Embodiment in detail The figure which shows the output color signal by the linear image sensor of 5th Embodiment The figure which shows an example of the color image signal calculated from the output color signal by the linear image sensor of 5th Embodiment The figure which shows schematic structure of an example of the conventional linear image sensor. The figure which shows the output signal of the linear image sensor of FIG. The figure which shows schematic structure of the other example of the conventional linear image sensor. The figure which shows the output signal of the linear image sensor of FIG.

Explanation of symbols

11, 11a, 11b ... red diode row 12, 12a, 12b ... green diode row 13, 13a, 13b ... blue diode row 21-23, 21a-23c ... charge transfer channel OUT31-OUT33, OUT31a to OUT33c ... output ends 51 to 56 ... channel stop regions H1 to H4 ... charge transfer electrodes 211, 211a to 211c ... red / blue diode rows 212, 212a to 212c ... green diode rows 221, 222, 221 a to 222 b, charge transfer channels OUT 231, OUT 232, OUT 231 a to OUT 232 b, output terminals 500, 600, photodiodes 511 to 513, 611, 612, photodiode arrays 521 to 523, 621, 622 ... charge transfer Sending units 531 to 533, 631, 632... Output units 541 to 543, 641, 642.

Claims (4)

A linear image sensor including a plurality of photoelectric conversion element arrays in which a plurality of photoelectric conversion elements are linearly arranged on a semiconductor substrate,
A charge transfer unit that transfers charges from the photoelectric conversion element;
An output unit that outputs a signal corresponding to the charge transferred by the charge transfer unit;
The photoelectric conversion elements included in the adjacent photoelectric conversion element rows are arranged so as to be shifted from each other in the column direction by about ½ of the pitch between the photoelectric conversion elements in the photoelectric conversion element row,
The charge transfer section includes a plurality of charge transfer channels formed on the semiconductor substrate corresponding to the columns of the photoelectric conversion element columns and a plurality of the charge transfer channels formed to intersect each of the charge transfer channels in plan view. A charge transfer electrode,
The charge transfer channel is formed close to the photoelectric conversion element so as to exhibit a meandering shape extending in the photoelectric conversion element column direction as a whole,
Each of the photoelectric conversion element rows is composed of photoelectric conversion elements for detecting charges corresponding to specific monochromatic light, and is provided adjacent to even columns corresponding to the same monochromatic light,
The charge transfer unit is a linear image sensor provided between two adjacent rows as the two adjacent rows of photoelectric conversion element rows corresponding to the same monochromatic light. The linear image sensor according to claim 1,
The linear image sensor formed between the photoelectric conversion elements so that the charge transfer electrodes have a meandering shape extending in a direction crossing the photoelectric conversion element array direction as a whole. The linear image sensor according to claim 1 or 2,
The charge transfer electrode is a linear image sensor provided with four each corresponding to the photoelectric conversion element. The linear image sensor according to any one of claims 1 to 3,
The monochromatic light is a linear image sensor having three types of red light, green light, and blue light.

Images