JPWO2004073302A1 - Imaging device - Google Patents

Abstract

An object of the present invention is to provide a camera that can read out photoelectrically converted charges at higher speed. The camera (1a) of the present invention belongs to one of the first pixel group irradiated with the light to be measured 5 and the second pixel group substantially not irradiated with the light to be measured, and has a first direction intersecting each other and A pixel that is two-dimensionally arranged in the second direction, and a horizontal transfer register (11) that receives and accumulates charges transferred from the pixel in the first direction and transfers the accumulated charges in the second direction; A synchronization circuit (20) that outputs a transfer signal for transferring charges to the pixel and the horizontal transfer register (11), and the synchronization circuit (20) photoelectrically converts pixels belonging to the second pixel group. The charges are superimposed in the first direction and accumulated in the horizontal transfer register (11), then transferred in the second direction, and the charges photoelectrically converted by the pixels belonging to the first pixel group are stepwise in the first direction. So that it is accumulated and transferred in the second direction. And outputs the signal.

Description

  The present invention relates to an imaging apparatus that measures light emitted from an object to be measured.

  As an imaging device that measures light emitted from a measurement object, there is a fluorescence imaging device that images fluorescence emitted from the measurement object irradiated with excitation light. This fluorescence imaging apparatus irradiates a living body measurement part with excitation light, and receives fluorescence emitted from the measurement part on an imaging surface of a CCD (Charge Coupled Device) imaging element on which a mosaic filter is on-chip. To do. When reading a signal from the CCD image sensor, first, the charges accumulated in each pixel (combination of photoelectric conversion element and charge storage element) on the imaging surface are sequentially transferred to the horizontal shift register line by line to the output circuit. Are read sequentially. The charges transferred from the fluorescence imaging area to the horizontal shift register are read out at a normal speed. The charges transferred from the non-imaging area are read out at a speed 10 times the normal speed. An example of this background art is described in a patent document (Japanese Patent Application Publication No. 2001-212072).

  Even in the above background art, the signal readout time can be shortened as compared with the case where charges transferred from all imaging regions are read out at a normal speed. However, there is a demand for reading out charges at a higher speed. However, in the conventional technique in which charges accumulated in each horizontal line are read out, there is a certain limit to speeding up the reading.

  Therefore, an object of the present invention is to provide an imaging device that can read out photoelectrically converted charges at higher speed.

  The present inventors have made various studies on the possibility of a reading method that can be used in combination with an increase in the charge reading speed. In the course of the study, since the charges transferred from the so-called non-imaging area are not used as data, it has been found that even if predetermined processing is performed, the substantial influence may be extremely small. The present invention has been made based on this finding.

  The imaging apparatus of the present invention belongs to either the first pixel group irradiated with the light to be measured or the second pixel group substantially not irradiated with the light to be measured, and the first direction and the second direction intersecting each other. Pixels that are two-dimensionally arranged in the direction, a horizontal transfer register that receives and accumulates charges transferred from the pixels in the first direction, and transfers the accumulated charges in the second direction, and pixels and horizontal transfer registers And a control means for outputting a transfer signal for transferring the charge to the pixel. The control means superimposes the charges photoelectrically converted by the pixels belonging to the second pixel group in the first direction and accumulates them in the horizontal transfer register. Is then transferred in the second direction, and a transfer signal is output so that the charges photoelectrically converted by the pixels belonging to the first pixel group are accumulated in each step in the first direction and transferred in the second direction. It is characterized by that.

  According to the image pickup apparatus of the present invention, the control unit accumulates the charges that are photoelectrically converted by the pixels belonging to the second pixel group so that charges that are not used as effective data can be collected. That is, since the charges photoelectrically converted by the pixels belonging to the second pixel group arranged in a plurality of stages can be swept out in one transfer in the second direction, the pixels belonging to the first pixel group have been photoelectrically converted. Charges can be read out at higher speed.

  In the imaging apparatus of the present invention, the control means outputs a transfer signal to the pixels belonging to the first pixel group, transfers the charges photoelectrically converted by the pixels in the first direction, and follows the second direction. When a pixel in one stage belongs to the first pixel group, a transfer signal is output to the horizontal transfer register in a stage before the charge photoelectrically converted by the pixel in the one stage is transferred to the horizontal transfer register. It is also preferable. Since the charges photoelectrically converted by the pixels belonging to the first pixel group are sequentially transferred and transferred to the horizontal transfer register, the control means outputs a transfer signal to the horizontal transfer register. Accumulated charges can be efficiently swept out.

  In the image pickup apparatus of the present invention, when the pixel in the first stage along the second direction includes a pixel belonging to the first pixel group and a pixel belonging to the second pixel group, the control means includes the second direction. When the charge is swept out from the horizontal transfer register corresponding to the pixel belonging to the first pixel group on the first stage along the line to be able to accept a new charge, the transfer signal is sent to the first stage pixel. Is also preferably transferred to the horizontal transfer register. For example, when the pixels near the center of the pixels on one stage belong to the first pixel group and the pixels near both ends belong to the second pixel group, the charges on the previous stage of this one stage are sequentially swept. If the horizontal transfer register corresponding to the pixel in the vicinity of the center of the first stage can accept a new charge, a transfer signal is output to the pixel of the first stage. In this case, although the charges photoelectrically converted by the pixels near both ends are superimposed on the charges of other stages, the charges photoelectrically converted by the pixels near both ends are substantially not used as valid data. The impact is extremely small. Accordingly, the charges photoelectrically converted by the pixels belonging to the first pixel group can be read out at higher speed.

  The imaging apparatus of the present invention preferably further includes an electronic shutter signal output means for outputting an electronic shutter signal for sweeping away charges generated in the pixels belonging to the second pixel group. Since the charges generated in the pixels that are not substantially irradiated with the light to be measured can be swept away, the charges generated in the pixels belonging to the first pixel group can be captured continuously after being transferred in the vertical direction.

  The imaging apparatus according to the present invention belongs to any one of a first photoelectric conversion element group irradiated with light to be measured and a second photoelectric conversion element group substantially not irradiated with the light to be measured, and intersects with each other. A photoelectric conversion element that is two-dimensionally arranged in a direction and a second direction; a charge that is photoelectrically converted by the photoelectric conversion element; and a first charge storage element that transfers the stored charge in a first direction; A charge transferred in the first direction is received and stored from the first charge storage element, a second charge storage element that transfers the stored charge in the second direction, a first charge storage element, and a second charge storage And a control means for outputting a transfer signal for transferring the charge to the element, wherein the photoelectric conversion element in one stage along the second direction is a photoelectric conversion element and a second photoelectric conversion element belonging to the first photoelectric conversion element group. Including a photoelectric conversion element belonging to a conversion element group. In this case, the control unit sweeps out charges from the second charge storage elements corresponding to the photoelectric conversion elements belonging to the first photoelectric conversion element group in the first stage along the second direction and can accept new charges. In this case, a transfer signal is output to the first charge storage element corresponding to the photoelectric conversion element in one stage to transfer the charge to the second charge storage element.

  According to the imaging apparatus of the present invention, the control unit accumulates the charges photoelectrically converted by the photoelectric conversion elements belonging to the second photoelectric conversion element group so that the charges that are not used as effective data can be collected. it can. That is, since the charge photoelectrically converted by the photoelectric conversion elements belonging to the second photoelectric conversion element group arranged over a plurality of stages can be swept out by one transfer in the second direction, the first photoelectric conversion element group The charge photoelectrically converted by the photoelectric conversion element to which it belongs can be read out at higher speed. Further, for example, in the case where the photoelectric conversion element in the vicinity of the center among the photoelectric conversion elements in one stage belongs to the first photoelectric conversion element group, and the photoelectric conversion elements in the vicinity of both ends belong to the second photoelectric conversion element group, When the charges in the previous stage of the one stage are sequentially swept out and the second charge storage element corresponding to the photoelectric conversion element near the center of the one stage can accept a new charge, A transfer signal is output to the first charge storage element corresponding to the photoelectric conversion element. In this case, the charges photoelectrically converted by the photoelectric conversion elements near both ends may be superimposed on the charges of other stages, but the charges photoelectrically converted by the photoelectric conversion elements near both ends are used as valid data. Since there is no charge, the substantial influence is very small. Therefore, the charges photoelectrically converted by the photoelectric conversion elements belonging to the first photoelectric conversion element group can be read out at higher speed.

  FIG. 1 is a diagram showing a configuration of a spectrometer that is an embodiment of the present invention.

  FIG. 2 is a diagram showing the configuration of the camera of FIG.

  FIG. 3A is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 3B is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 3C is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 3D is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 3E is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4A is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4B is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4C is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4D is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4E is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4F is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 4G is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5A is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5B is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5C is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5D is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5E is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 5F is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 5G is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6A is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6B is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6C is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6D is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6E is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6F is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 6G is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6H is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6I is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6J is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6K is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 6L is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7A is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7B is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7C is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7D is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 7E is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7F is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 7G is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7H is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7I is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 7J is a diagram for explaining a charge reading method in the camera of FIG. 2.

  FIG. 7K is a diagram for explaining a charge reading method in the camera of FIG.

  FIG. 8A is a diagram for explaining a charge reading method according to the embodiment of the present invention.

  FIG. 8B is a diagram for explaining the charge reading method according to the embodiment of the present invention.

  FIG. 8C is a diagram for explaining the charge reading method according to the embodiment of the present invention.

  FIG. 8D is a diagram for explaining the charge reading method according to the embodiment of the present invention.

  FIG. 8E is a diagram for explaining a charge reading method according to the embodiment of the present invention.

  FIG. 9A is a diagram for explaining the operation timing of the CCD according to the embodiment of the present invention.

  FIG. 9B is a diagram for explaining the operation timing of the CCD according to the embodiment of the present invention.

  FIG. 10A is a diagram for explaining the operation timing of the CCD according to the embodiment of the present invention.

  FIG. 10B is a diagram for explaining the operation timing of the CCD according to the embodiment of the present invention.

  FIG. 11 is a diagram showing a configuration of a streak camera according to an embodiment of the present invention.

  The knowledge of the present invention can be easily understood by considering the following detailed description with reference to the accompanying drawings shown for illustration only. Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  A spectroscope (imaging device) 1 according to an embodiment of the present invention will be described. FIG. 1 is a diagram showing the configuration of the spectrometer 1. The spectroscope 1 includes a spectroscopic optical system 2 and a camera (imaging device) 1a. The light to be measured 5 passes through the spectroscopic optical system and irradiates a predetermined region (described in FIG. 2) of the imaging unit 10 of the camera 1. The imaging unit 10 reads out data by each pixel performing photoelectric conversion and charge transfer according to a pulse signal output from the synchronization circuit (control unit, electronic shutter signal output unit) 20. The read data is output to the outside via the read circuit 22. The synchronization circuit 20 outputs a pulse signal to the imaging unit 10 based on the external synchronization signal and the internal synchronization signal. This output timing is appropriately set based on an instruction signal from the control unit (control unit, electronic shutter signal output unit) 21.

  The configurations of the spectroscopic optical system 2 and the camera 1a are shown in FIG. The spectroscopic optical system 2 includes a lens 3 and a slit 4, and the light to be measured 5 incident on the lens 3 passes through the lens 3 and the slit 4 and is applied to a predetermined region 10 a of the imaging unit 10.

  The image pickup unit 10 is constituted by a CCD image pickup device. In the case of this embodiment, a frame transfer method is employed in which each pixel receives and photoelectrically converts charges received by each pixel and outputs data. A predetermined signal is output from the synchronization circuit 20 to each pixel of the imaging unit 10 via the signal line 20a. A predetermined signal is output from the synchronization circuit 20 to each charge storage element of the horizontal transfer register 11 via the signal line 20b.

  Each pixel of the imaging unit 10 is exposed according to an exposure signal from the synchronization circuit 20, and photoelectrically converts the received light. Each pixel of the imaging unit 10 further transfers the electric charge accumulated by the photoelectric conversion in accordance with the transfer signal from the synchronization circuit 20 in the direction toward the horizontal transfer register 11 (first direction). When charges are transferred to pixels adjacent to the horizontal transfer register 11 of the imaging unit 10, the charges are transferred to the horizontal transfer register 11.

  The horizontal transfer register 11 transfers the charge transferred from the imaging unit 10 in the direction toward the readout circuit 22 (second direction) in response to the transfer signal from the synchronization circuit 20. Therefore, by using this camera 1a, it is possible to measure the light to be measured 5 irradiated onto the predetermined area 10a of the imaging unit 10 and output the measurement result to the outside as output data.

  A more specific charge reading method will be described with reference to FIGS. 3A to 3E. FIG. 3A is a diagram schematically illustrating a state in which the measurement target light 5 is irradiated to the imaging unit 10 and each pixel of the imaging unit 10 receives light. The pixels of the imaging unit 10 are arranged in a first stage 101 to a sixth stage 106. Ten pixels are arranged in each stage. Accordingly, the pixels of the imaging unit 10 are two-dimensionally arranged in the horizontal direction and the vertical direction. Pixels corresponding to the predetermined region 10a in FIG. 2 are pixels arranged in the third and fourth stages. In FIG. 3A, the region marked with a circle indicates that the pixel to be measured 5 is irradiated, and the region marked with a single oblique line is substantially irradiated with the beam to be measured 5. This indicates that there is no pixel.

  From the state of FIG. 3A, a transfer signal is input from the synchronization circuit 20 to each pixel of the imaging unit 10. The electric charge of each pixel of the imaging unit 10 is transferred in the direction of the horizontal transfer register 11 step by step. Therefore, as shown in FIG. 3B, the charge accumulated in the pixels of the sixth stage 106 of the imaging unit 10 is transferred to the horizontal transfer register 11. Furthermore, when a transfer signal is input from the synchronization circuit 20 to the imaging unit 10, the charge accumulated in the pixels of the fifth stage 105 in FIG. 3A is also transferred to the horizontal transfer register 11. Therefore, in FIG. 3C, the charges photoelectrically converted in the pixels of the fifth stage 105 and the sixth stage 106 in FIG. 3A are superposed in the horizontal transfer register 11. In FIG. 3C, double hatched lines are written in each area of the horizontal transfer register 11 in this way, indicating that charges in two stages are overlapped.

  From the state of FIG. 3C, a transfer signal is input from the synchronization circuit 20 to the horizontal transfer register 11, and the charges accumulated in the horizontal transfer register 11 are sequentially swept out (FIG. 3D)). 3C is not transferred to the horizontal transfer register 11 in the pixel of the fourth stage 104 in FIG. 3A because the pixel of the fourth stage 104 in FIG. This is because the effective data is accumulated. Therefore, after all the charges accumulated in the horizontal transfer register 11 are discharged, a transfer signal is input from the synchronization circuit 20 to the imaging unit 10, and the charges photoelectrically converted in the pixels of the fourth stage 104 in FIG. The data is transferred to the transfer register 11 (FIG. 3E). Thereafter, a transfer signal is input from the synchronization circuit 20 to the horizontal transfer register 11, and the electric charge photoelectrically converted in the pixels of the fourth stage 104 in FIG. 3A is swept out as output data to the outside.

  Another charge reading method will be described with reference to FIGS. 4A to 4G. FIG. 4A is a diagram schematically illustrating a state in which the measurement target light 5 is irradiated to the imaging unit 10 and each pixel of the imaging unit 10 receives light. The example shown in FIG. 3A is different from the example in FIG. 4A in the predetermined region 10a irradiated with the light 5 to be measured. That is, in the example shown in FIG. 3A, the measured light 5 is irradiated over the entire width of the imaging unit 10, but in the example shown in FIG. 4A, the measured light 5 is irradiated only near the center of the imaging unit 10. Yes. Therefore, the pixels corresponding to the predetermined region 10a in FIG. 2 are four pixels in each stage near the center among the pixels arranged in the third and fourth stages. In FIG. 4A, a region with a circle indicates that the pixel to be measured 5 is irradiated, and a region with a single diagonal line is substantially irradiated with the light to be measured 5. This indicates that there is no pixel.

  From the state of FIG. 4A, a transfer signal is input from the synchronization circuit 20 to each pixel of the imaging unit 10. The electric charge of each pixel of the imaging unit 10 is transferred in the direction of the horizontal transfer register 11 step by step. Therefore, as shown in FIG. 4B, the charges accumulated in the pixels of the sixth stage 106 of the imaging unit 10 are transferred to the horizontal transfer register 11. Furthermore, when a transfer signal is input from the synchronization circuit 20 to the imaging unit 10, the charge accumulated in the pixels of the fifth stage 105 in FIG. 4A is also transferred to the horizontal transfer register 11. Therefore, in FIG. 4C, the charges photoelectrically converted in the pixels of the fifth stage 105 and the sixth stage 106 in FIG. 4A are superposed in the horizontal transfer register 11. In FIG. 4C, double hatched lines are written in each area of the horizontal transfer register 11 in this way, indicating that charges in two stages are overlapped.

  From the state of FIG. 4C, a transfer signal is input from the synchronization circuit 20 to the horizontal transfer register 11, and the charges accumulated in the horizontal transfer register 11 are sequentially swept out. As shown in FIG. 4D, the charges accumulated in the horizontal transfer register 11 are sequentially swept out, and the charges in the charge accumulation elements of the horizontal transfer register 11 corresponding to the circled pixels in the fourth stage 104 in FIG. 4A. Is transferred and a transfer signal is output from the synchronization circuit 20 to the imaging unit 10 when the charge storage element is ready to accept a new charge. Therefore, as shown in FIG. 4E, the charges photoelectrically converted by the pixels marked with the circles in the fourth stage 104 in FIG. 4A are delivered to the horizontal transfer register 11 without being overlaid with other charges. In the charge storage element closer to the reading circuit than the charge storage element that has received the photoelectrically converted charge of the pixel marked with the circle in the fourth stage 104 in FIG. 4A, the fourth stage 104, the fifth stage 105, and the Charges photoelectrically converted by the pixels of the six stages 106 are accumulated and accumulated.

  4E, the transfer signal is output from the synchronization circuit 20 to the horizontal transfer register 11 and the charges accumulated in the horizontal transfer register 11 are sequentially swept out. As shown in FIG. 4F, the charges accumulated in the horizontal transfer register 11 are sequentially swept out, and the charges in the charge accumulation elements of the horizontal transfer register 11 corresponding to the circled pixels in the third stage 103 in FIG. 4A. Is transferred and a transfer signal is output from the synchronization circuit 20 to the imaging unit 10 when the charge storage element is ready to accept a new charge. Therefore, as shown in FIG. 4G, the charges photoelectrically converted by the pixels marked with the third stage 103 in FIG. 4A are delivered to the horizontal transfer register 11 without being overlaid with other charges.

  A method of reading out charges when an interline CCD is used as the imaging unit will be described with reference to FIGS. 5A to 5G. Each pixel of the imaging unit 12 includes a photodiode 14a as a photoelectric conversion element and a vertical transfer CCD 14b as a charge storage element that accumulates and transfers charges photoelectrically converted by the photodiode 14a. The pixels of the imaging unit 12 are divided into a first stage 121 to a sixth stage 126, and 10 pixels are arranged in each stage. Accordingly, the pixels of the imaging unit 12 are two-dimensionally arranged in the horizontal direction and the vertical direction.

  FIG. 5A is a diagram schematically illustrating a state in which the measurement target light 5 is irradiated to the imaging unit 12 and each pixel of the imaging unit 12 receives light. In FIG. 5A, it is assumed that the region under measurement “A” is irradiated with the light to be measured 5. In the state of FIG. 5A, when a transfer pulse signal is output from the synchronization circuit 20 to the imaging unit 12, the charge photoelectrically converted by the photodiode 14a of each pixel is output to the vertical transfer CCD 14b, resulting in the state shown in FIG. 5B. . Since the photodiode 14a of each pixel is in an exposureable state when photoelectrically converted charges are output, as shown in FIG. 5C, the light to be measured 5 can be received at the same portion as FIG. 5A. In order to distinguish from the light received in FIG. 5A, “B” is given to the region irradiated with the light to be measured 5 in FIG. 5C. In this way, while the light to be measured 5 is newly received, the electric charge (“A”) output to the vertical transfer CCD in FIG. 5B is transferred in the horizontal transfer register 13 direction. When the charge is transferred from the vertical transfer CCD corresponding to the region marked with “B” and the charge is newly accepted, a transfer pulse signal is output from the synchronization circuit 20 to the imaging unit 12. The state shown in FIG. 5D is obtained.

  Since the photodiode 14a of each pixel is exposed to light when photoelectrically converted charges are output, the measured light 5 can be received at the same portion as in FIGS. 5A and 5C as shown in FIG. 5E. In order to distinguish from the light received in FIGS. 5A and 5C, “C” is given to the region irradiated with the light to be measured 5 in FIG. 5E. The charges (“A” and “B”) output to the vertical transfer CCD while receiving the measurement light 5 anew in this way are transferred in the direction of the horizontal transfer register 13 and are transferred to the first transfer in FIG. 5A. The charge (“A”) photoelectrically converted in the four stages 124 is transferred to the horizontal transfer register 13.

  The electric charge (“A”) delivered to the horizontal transfer register 13 is transferred in the direction of the readout circuit and enters the state shown in FIG. 5F. As shown in FIG. 5F, the charges accumulated in the horizontal transfer register 11 are sequentially swept out, and the charge (“A”) in the fourth stage 124 in FIG. 5A is swept out, and the corresponding charge accumulating element is renewed. When the charge can be received, a transfer signal is output from the synchronization circuit 20 to the imaging unit 12. Therefore, as shown in FIG. 5G, the charges photoelectrically converted by the pixels marked with the third stage 123 in FIG. 5A are transferred to the horizontal transfer register 11 without being overlaid with other charges.

  A method for reading out charges when a frame transfer type (frame transfer type) CCD is used as the imaging unit will be described with reference to FIGS. 6A to 6F.

  The imaging unit 15 is of a frame transfer type (frame transfer type) having a light detection unit 15a and a storage unit 15b separately. In the imaging unit 15, a plurality of pixels P are two-dimensionally arranged along a vertical direction (up and down direction in the figure) and a horizontal direction (left and right direction in the figure). Here, a case where a total of 120 pixels P are arranged in 12 stages in the vertical direction will be described as an example. At this time, 10 pixels are arranged in each stage along the horizontal direction.

  These pixels P are divided into pixels constituting the light detection unit 15a and pixels constituting the storage unit 15b. That is, 60 pixels included in the upper half (from the first stage to the sixth stage from the top) of all the pixels P constitute the light detection unit 31, and the lower half (from the seventh stage to the twelfth stage from the top). 60 pixels included in () form the storage unit 15b. In each pixel P constituting the light detection unit 15a, the incident measurement light 5 is subjected to photoelectric conversion, and charges generated by the photoelectric conversion are transferred one by one in the vertical direction. The charges transferred in the vertical direction from the pixel at the lowermost stage (sixth stage 156) of the light detection unit 15a are transferred to the pixel at the uppermost stage (first stage 157) of the storage unit 15b. In each pixel constituting the storage unit 15b, the charges transferred from the light detection unit 15a are transferred one by one in the vertical direction.

  A horizontal transfer register 16 is provided adjacent to the lowermost stage (sixth stage 162) of the storage unit 15b. The charges transferred in the vertical direction from the pixel at the lowermost stage (sixth stage 162) of the storage unit 15b are transferred to the horizontal transfer register 16. In the horizontal transfer register 16, the charge transferred from the storage unit 15b is transferred in the horizontal direction and output as a detection signal.

  FIG. 6A is a diagram schematically illustrating a state in which the light to be measured 5 is irradiated on the light detection unit 15a and each pixel of the light detection unit 15a receives light. In FIG. 6A, it is assumed that the region under measurement “A” is irradiated with the light to be measured 5. FIG. 6B shows a state immediately after the charge generated in each pixel belonging to the detection unit 15a is transferred to the storage unit 15b. That is, in FIG. 6A, the charge generated in response to the irradiation of the light to be measured 5 is accumulated in each pixel of the first stage 157 and the second stage 158 of the accumulation unit 15b as shown in FIG. 6B. When all the charges generated in response to the irradiation of the light to be measured 5 are transferred to the storage unit 15b, an electronic shutter signal is sent to the light detection unit 15a immediately after that, and the light to be measured 5 is detected in the light detection unit 15a. All the charges generated in the pixels that are not irradiated are swept away (see FIG. 6C).

  Further, in the light detection unit 15a, the next exposure is performed immediately after the charge is swept away. In FIG. 6D, it is assumed that the region under measurement “B” is irradiated with the light to be measured 5. The charges generated by the light detection unit 15a by this exposure are transferred to the storage unit 15b. FIG. 6E shows a state immediately after the charge generated in response to the irradiation of the light to be measured 5 is transferred to the storage unit 15b. At this time, the charge generated in the light detection unit 15a by the previous exposure is transferred to the third stage 159 and the fourth stage 160.

  After the above operation is repeated and all the charges generated in response to the irradiation of the light under measurement 5 are sequentially stored in all of the first stage 157 to the sixth stage 162 of the storage unit 15b, these charges are stored in the horizontal transfer register one by one. 16, and charges are sequentially transferred to the readout circuit 22 by the horizontal transfer register 16. Also during this operation, the light detection unit 15a performs exposure. However, this exposure time must be set to be equal to or less than the time required for the horizontal transfer register 16 to transfer all charges for one stage. In FIG. 6F, the charges generated by the first exposure are accumulated in the fifth stage 161 and the sixth stage 162, and the charges generated by the second exposure are accumulated in the third stage 159 and the fourth stage 160. Charges generated by the third exposure are accumulated in the first stage 157 and the second stage 158 (indicated by “C” in the figure). When the horizontal transfer register 16 transfers all the charges of the first stage (bottom stage) toward the readout circuit 22, it subsequently transfers the charges of the next stage. As described above, in the read operation according to this example, only the charges generated in response to the irradiation of the light to be measured 5 are output as substantial detection signals.

  In this example, the control unit 21 (electronic shutter signal output means) outputs an electronic shutter signal, thereby sweeping out charges generated in each pixel not irradiated with the light under measurement 5. Thereby, only the electric charge generated according to the irradiation of the light to be measured 5 can be repeatedly transferred to the accumulation unit. Further, since the transfer by the horizontal transfer register 16 is also performed during exposure in the light detection unit 15a, the time required for the horizontal transfer register 16 to horizontally transfer charges generated in response to the irradiation of the light to be measured 5 is minimized. Data can be acquired repeatedly. In this example, in particular, since the region to be irradiated with the light to be measured 5 is set so as to include the pixels of the sixth stage 156 adjacent to the storage unit 15b in the light detection unit 15a, the region to be irradiated with the light to be measured 5 is set. The information of the predetermined area 10a can be read one after another without any gaps at time intervals for transferring charges for several lines (two lines in this example) in the vertical direction. Therefore, the detection signal can be read out at a particularly high speed.

  After FIG. 6F, exposure and readout as will be described subsequently are performed. This exposure and readout will be described with reference to FIGS. 6G to 6L. When further exposure is performed from the state of FIG. 6F, the state of FIG. 6G is obtained. Here, all the pixels of the storage unit 15b are filled with the delivered charges. When vertical transfer for one line is performed from the state of FIG. 6G, the state shown in FIG. 6H is obtained. When the vertical transfer for one line is subsequently performed, the state shown in FIG. 6I is obtained. In the state shown in FIG. 6I, the electric charge accumulated in the first exposure (the portion marked with “A” in the figure) is stored in the horizontal transfer register 16 in a superimposed state (indicated by “AA” in the figure). Here, when the electronic shutter signal is output, the charges of the pixels belonging to the light detection unit 15a are again swept away (see FIG. 6J).

  Here, by sequentially reading out the horizontal transfer register 16, it is possible to acquire an image while maintaining the horizontal resolution (since the charges are superimposed in the vertical direction). Further, the next exposure is performed during the reading period of the horizontal transfer transfer register 16 (see FIG. 6K, “e” in the figure indicates a state during the exposure). When the reading of the horizontal transfer register 16 is completed, a new exposure is also completed (see FIG. 6L. “E” in the figure indicates a state where the exposure is completed). Since the state shown in FIG. 6L is equivalent to the state shown in FIG. 6G, when the exposure and reading described with reference to FIGS. 6H to 6L are repeated, the images are continuously displayed without unnecessarily reducing the repetition rate of the image output. Output is possible.

  Still another example of exposure and readout will be described with reference to FIGS. 7A to 7K. In FIGS. 6A to 6L, the example in which the vertical alignment is performed for each predetermined region 10a in the horizontal reading stage has been described. In FIGS. 7A to 7K, a case where superimposition in the vertical direction is not performed will be described. 7A to 7C, exposure and transfer similar to those described with reference to FIGS. 6A to 6C are performed. In the case of a frame transfer type CCD, the light detection unit 15a and the storage unit 15b can be independently driven in the vertical direction. Therefore, from the state shown in FIG. 7C, while the light detection unit 15a performs exposure (indicated by “b” in the figure), the storage unit 15b performs transfer in the vertical direction. When the vertical transfer in the storage unit 15b is performed for two lines, the exposure in the light detection unit 15a is completed (see FIG. 7E). The reason why driving is performed so that a gap of two lines is generated as shown in FIG. 7E is because two lines are set as the predetermined region 10a. Therefore, this gap is set based on an appropriate value derived from the number of lines in the storage section and the vertical unit of the predetermined area 10a.

  From the state shown in FIG. 7E, both the light detection unit 15a and the storage unit 15b perform vertical transfer, resulting in the state shown in FIG. 7F. An electronic shutter signal is output from the state shown in FIG. 7F to sweep away the charges accumulated in the light detection unit 15a (see FIG. 7G). When one line is further transferred vertically from the state of FIG. 7G, the first line of charge indicated by “A” is transferred to the horizontal transfer register 16 as shown in FIG. 7H. Here, as shown in FIG. 7I, exposure is performed by the light detection unit 15a while reading out the horizontal transfer register 16 ("c" in the figure indicates that exposure is in progress). When the reading of the charge “A” in the first line is completed, the vertical transfer is further performed only to the storage unit 15b, and the charge “A” in the next line is transferred to the horizontal transfer register 16 (see FIG. 7J). Here, when the reading of the horizontal transfer register 16 is completed, the exposure in the light detection unit 15a is also completed and the state shown in FIG. 7K is obtained. Since the state shown in FIG. 7K is equivalent to the state shown in FIG. 7E, when the exposure and reading described with reference to FIGS. 7F to 6K are repeated, the image is displayed without unnecessarily reducing the repetition rate of the image output. It is possible to output continuously.

  The effects of the charge reading method described with reference to FIGS. 3A to 3E, 4A to 4G, 5A to 5G, and 6A to 6F will be described with reference to FIGS. 8A to 8E. 8A is a timing chart of the conventional reading method, FIG. 8B is a timing chart of the reading method described using FIGS. 3A to 3E, and FIG. 8C is a timing chart of the reading method described using FIGS. 4A to 4G. 8D is a timing chart of the reading method described with reference to FIGS. 5A to 5G, and FIG. 8E is a timing chart of the reading method described with reference to FIGS. 6A to 6F. 8A to 8D, the upper stage shows vertical synchronization and the lower stage shows horizontal synchronization. The timing chart shown in FIG. 8E shows the upper stage with vertical synchronization, the middle stage with horizontal synchronization, and the lower stage with electronic shutter signals. Respectively. Further, in the lower row, circles or letters are attached, the readout charge of the portion irradiated with the light to be measured 5, and the shaded lines indicate that the light to be measured 5 is substantially irradiated. It shows that the read charges of the parts that are not read are the parts that have been read.

  In the conventional method shown in FIG. 8A, the charges photoelectrically converted by the pixels at each stage are read out one by one, so that six stages of horizontal readout are required. On the other hand, in the method shown in FIG. 8B (the reading method described with reference to FIGS. 3A to 3E), the charges photoelectrically converted by the pixels that are not irradiated with the light to be measured 5 are superimposed, so the transfer rate in the horizontal direction Even if they are the same, the charge readout time for one charge can be shortened.

  In the method shown in FIG. 8C (the reading method described with reference to FIGS. 4A to 4G), since some pixels in each stage receive the light to be measured 5, the pixels in the same stage as that pixel are In addition, since the charges photoelectrically converted by the pixels not receiving the light to be measured 5 are read out in a superimposed manner, the charge reading time for one time can be further shortened.

  In the method shown in FIG. 8D (reading method described with reference to FIGS. 5A to 5G), since an interline CCD is used, reading is not affected by the reading of the pixels not receiving the light to be measured 5. The charge of the pixel receiving the measurement light 5 can be read out. Further, since reading and exposure can be performed simultaneously, the output data can be handled as a two-dimensional image.

  In the method shown in FIG. 8E (the reading method described with reference to FIGS. 6A to 6F), since the frame transfer type CCD is used, the light receiving element and the vertical transfer element are the same, and an electronic shutter is used. Other charges can be swept away during the transfer of charges generated in response to reception of the light to be measured 5.

  The operation timing of each CCD during the operation described with reference to FIGS. 3A to 3E, 4A to 4G, and 5A to 5G will be described with reference to FIGS. 9A, 9B, 10A, and 10B. FIG. 9A is a timing chart when the operation described with reference to FIGS. 3A to 3E or FIGS. 4A to 4G is performed using a frame transfer type CCD. FIG. 9B shows a timing chart when the operation described with reference to FIGS. 3A to 3E or FIGS. 4A to 4G is performed using an interline CCD. 9A and 9B, PIV is an image area shift pulse signal of the frame transfer CCD, PSV is a memory area shift pulse signal of the frame transfer CCD, PH is a horizontal CCD shift pulse signal, and SG is vertical from the photodiode. A transfer pulse signal to the CCD, PV indicates a vertical shift pulse signal, and VV indicates a vertical effective signal. The frame transfer type CCD is assumed to have an image area of 10 × 6 and a memory area of 10 × 6. 9A and 9B are compared, when performing the operation described with reference to FIGS. 3A to 3E or FIGS. 4A to 4G, any of the frame transfer type CCD and the interline type CCD is used. It can be seen that reading can be performed at almost the same speed even when used.

  FIG. 10A is a timing chart when the operation described with reference to FIGS. 5A to 5G is performed using an interline CCD. FIG. 10B shows a timing chart when the operation described with reference to FIGS. 5A to 5G is performed using a frame transfer type CCD. The symbols used in FIGS. 10A and 10B are the same as those used in FIGS. 9A and 9B. Comparing the vertical effective signals of FIGS. 10A and 10B, when the operation described with reference to FIGS. 5A to 5G is performed, the speed can be significantly improved by using the interline CCD. I understand that This is because the interline type CCD adds the necessary area as it is to the unnecessary area, whereas the frame transfer type CCD cannot perform the operation.

  A streak camera (imaging device) 6 which is another embodiment of the present invention will be described. FIG. 11 is a diagram showing the configuration of the streak camera 6. The streak camera 6 includes a streak optical system 8, a camera (imaging device) 6 a, a streak synchronization circuit 81, a timing generator 82, and a light source 9. The timing generator 82 outputs a synchronization signal to the streak synchronization circuit 81 and the camera 6a according to the light emission of the light source 9. When the light source 9 emits light and irradiates an object to be measured (not shown) with excitation light, measured light 7 is generated and introduced into the streak optical system 8. The streak optical system 8 time-resolves the measured light 7 by a streak synchronization circuit 81 and outputs it as a slit image 7a to the camera 6a side.

  The slit image 7a is formed on a predetermined area (not shown) of the imaging unit 10 of the camera 6a. The imaging unit 10 reads out data by each pixel performing photoelectric conversion and charge transfer according to the pulse signal output from the synchronization circuit 25. The read data is output to the outside via the read circuit 22. The synchronization circuit 25 outputs a pulse signal to the imaging unit 10 according to the external synchronization signal and the instruction signal from the control unit 26. Since the method for reading the electric charge of the imaging unit 10 is the same as that already described, the description thereof is omitted.

  In the present embodiment, the control unit 21 and the synchronization circuit 20 accumulate the charges in the horizontal transfer register 11 so that the charges photoelectrically converted by the pixels belonging to the second pixel group that are not substantially irradiated with the light to be measured 5 are superimposed. Therefore, charges that are not used as valid data can be collected. In other words, since the charges photoelectrically converted by the pixels belonging to the second pixel group arranged in a plurality of stages can be swept away by one transfer in the horizontal direction, the first pixel group irradiated with the light to be measured 5 is irradiated. The charges photoelectrically converted by the pixels belonging to can be read out at higher speed.

  In the present embodiment, the synchronous circuit 20 transfers the charges photoelectrically converted by the pixels belonging to the first pixel group to the horizontal transfer register 11 before the charges are sequentially transferred to the horizontal transfer register 11. Since the signal is output, the charge accumulated in the horizontal transfer register 11 can be efficiently swept out.

  Further, in the present embodiment, when the pixels near the center of the pixels on one stage belong to the first pixel group and the pixels near both ends belong to the second pixel group, the previous stage of this one stage. When the horizontal transfer register 11 corresponding to the pixel in the vicinity of the center of one stage can accept a new charge, the transfer signal is output to the pixel of the first stage. To do. In this case, although the charges photoelectrically converted by the pixels near both ends are superimposed on the charges of other stages, the charges photoelectrically converted by the pixels near both ends are substantially not used as valid data. The impact is extremely small. Accordingly, the charges photoelectrically converted by the pixels belonging to the first pixel group can be read out at higher speed.

  As described above, according to the present invention, the control unit accumulates the charges that are photoelectrically converted by the pixels belonging to the second pixel group so that charges that are not used as effective data can be collected. That is, since the charges photoelectrically converted by the pixels belonging to the second pixel group arranged in a plurality of stages can be swept out in one transfer in the second direction, the pixels belonging to the first pixel group have been photoelectrically converted. Charges can be read out at higher speed.

Claims (5)

The first pixel group irradiated with the light to be measured and the second pixel group substantially not irradiated with the light to be measured belong to any one of the first and second directions intersecting each other. Pixels
A horizontal transfer register that receives and accumulates charges transferred in the first direction from the pixels, and transfers the accumulated charges in the second direction;
Control means for outputting a transfer signal for transferring the charge to the pixel and the horizontal transfer register,
The control means includes
Charges photoelectrically converted by pixels belonging to the second pixel group are superimposed in the first direction and accumulated in the horizontal transfer register and then transferred in the second direction,
An image pickup apparatus that outputs the transfer signal so that charges photoelectrically converted by pixels belonging to the first pixel group are accumulated step by step in the first direction and transferred in the second direction. . The control means includes
Outputting the transfer signal to the pixels belonging to the first pixel group, causing the photoelectric conversion of the pixels to be transferred in the first direction, and
When a pixel at one stage along the second direction belongs to the first pixel group, the horizontal photoelectric conversion is performed at the stage before the charge photoelectrically converted by the pixel at the first stage is transferred to the horizontal transfer register. The imaging apparatus according to claim 1, wherein the transfer signal is output to a transfer register. In the case where the pixels in one stage along the second direction include pixels belonging to the first pixel group and pixels belonging to the second pixel group,
The control means includes
In the case where charges are swept out from the horizontal transfer register corresponding to the pixels belonging to the first pixel group in one stage along the second direction and new charges can be accepted, The imaging apparatus according to claim 1, wherein the transfer signal is output to a pixel in a stage to transfer charges to the horizontal transfer register. The imaging apparatus according to claim 1, further comprising an electronic shutter signal output unit that outputs an electronic shutter signal for sweeping away charges generated in pixels belonging to the second pixel group. The first photoelectric conversion element group irradiated with the light to be measured and the second photoelectric conversion element group substantially not irradiated with the light to be measured belong to any one of the first direction and the second direction intersecting each other. Two-dimensionally arranged photoelectric conversion elements;
A first charge storage element that accumulates charges photoelectrically converted by the photoelectric conversion element and transfers the accumulated charges in the first direction;
A second charge storage element that receives and accumulates charges transferred in the first direction from the first charge accumulation element, and transfers the accumulated charges in the second direction;
Control means for outputting a transfer signal for transferring the charge to the first charge storage element and the second charge storage element;
When the one-stage photoelectric conversion element along the second direction includes a photoelectric conversion element belonging to the first photoelectric conversion element group and a photoelectric conversion element belonging to the second photoelectric conversion element group,
The control means includes
When charges are swept out from the second charge storage elements corresponding to the photoelectric conversion elements belonging to the first photoelectric conversion element group in the first stage along the second direction so that new charges can be accepted. The image pickup apparatus is characterized in that the transfer signal is output to the first charge storage element corresponding to the photoelectric conversion element in the first stage to transfer the charge to the second charge storage element.

Images