JPH10191171A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image with high sensitivity even for an exposure over a long time by driving a charge transfer path of a CCD(charge coupled device) with a low frequency signal during exposure of the CCD. SOLUTION: When exposure of a photoelectric sensor 60 of a CCD 6 is started and an exposure start signal is received, a CPU 12 provides an output of a low frequency drive signal to a read control circuit 66 to allow a charge transfer path 64 to be driven at a low frequency signal so as to transfer charges to an output amplifier 62 and outputs a power control signal to an output amplifier power supply circuit 68 thereby reducing power fed from the output amplifier power supply circuit 68 to the output amplifier 62. After the lapse of a prescribed exposure time, a CPU 30 outputs an exposure end signal to a CPU 12 of the image pickup device 1. Upon the receipt of the exposure end signal from the CPU 30, the CPU 12 outputs a high frequency drive signal to the read control circuit 66 to drive the charge transfer path 64 with a high frequency signal so as to transfer the charge stored in the photoelectric sensor 60 to the output amplifier 62 via the charge transfer path 64.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus using a CCD (Charge Coupled Device). The present invention relates to an imaging device capable of reducing noise caused by heat and obtaining a high-quality image.

[0002]

2. Description of the Related Art An immobilized polymer such as a protein or nucleic acid sequence is selectively labeled with a labeling substance that causes chemiluminescence upon contact with a chemiluminescent substance, and is selectively labeled with the labeling substance. The polymer is brought into contact with the chemiluminescent substance, and the chemiluminescence in the visible light wavelength region caused by the contact between the chemiluminescent substance and the labeling substance is photoelectrically detected, and a digital image signal is generated to perform image processing. A chemiluminescence detection system is known in which a chemiluminescence image is reproduced on a display means such as a CRT or a recording material such as a photographic film to obtain information on a macromolecule such as genetic information. Also, a fluorescence detection system using a fluorescent substance as a labeling substance is known. According to this fluorescence detection system, by reading a fluorescence image, it is possible to perform gene sequence, gene expression level, protein separation and identification, or molecular weight and property evaluation. D
After adding a fluorescent dye to the solution containing the NA fragment, a plurality of DNA fragments are subjected to electrophoresis on a gel support, or a plurality of DNA fragments are placed on a gel support containing a fluorescent dye.
The A fragment is electrophoresed, or a plurality of DNA fragments are electrophoresed on a gel support, and then the gel support is immersed in a solution containing a fluorescent dye. By labeling, exciting a fluorescent dye with excitation light, and detecting the generated fluorescence, an image is generated, and the distribution of DNA on the gel support is detected. After electrophoresis on a support, the DNA is denaturated and then
A probe prepared by transferring at least a portion of a denatured DNA fragment onto a transfer support such as nitrocellulose by Southern blotting, and labeling DNA or RNA complementary to the target DNA with a fluorescent dye D
An image is generated by hybridizing with an NA fragment, selectively labeling only a DNA fragment complementary to a probe DNA or a probe RNA, exciting a fluorescent dye with excitation light, and detecting generated fluorescence. Then, the distribution of the target DNA on the transcription support can be detected. Further, a DNA probe complementary to the DNA containing the target gene labeled with the labeling substance is prepared, hybridized with the DNA on the transcription support, and the enzyme is reacted with the complementary DNA labeled with the labeling substance. After binding, the fluorescent substance is brought into contact with a fluorescent substrate, the fluorescent substrate is changed into a fluorescent substance that emits fluorescence, and the generated fluorescent substance is excited by excitation light, and the generated fluorescence is detected.
An image can be generated to detect the distribution of the target DNA on the transfer support. This fluorescence detection system has an advantage that a gene sequence or the like can be easily detected without using a radioactive substance.

[0003] Such a chemiluminescent or fluorescent light is cooled by a cooled CCD.
When a chemiluminescent image or a fluorescent image is detected by an image pickup device using a fluorescent light and a chemiluminescent image or a fluorescent image is generated, exposure is required for a long time because the chemiluminescence or the fluorescent light is very weak light. It is known that, when exposure is performed, noise is generated in an image due to heat generated by the CCD. In order to reduce such noise due to heat, an imaging device for detecting extremely weak light such as chemiluminescence or fluorescence has means for cooling the CCD.

[0004]

However, in order to obtain an image with high sensitivity, if the exposure time is lengthened, no matter how much cooling is performed, charges are generated and accumulated in the charge transfer path of the CCD during exposure. However, it has been difficult to reduce image noise caused by the charges. A similar problem occurs when an image is generated by detecting very weak light with a solid-state imaging device, such as in astronomical observation. Therefore, an object of the present invention is to provide an imaging device that includes a CCD and can obtain an image with high sensitivity even when exposed for a long time.

[0005]

The object of the present invention is attained by an image pickup apparatus provided with a drive means for driving a charge transfer path of the CCD at a low frequency during exposure of the CCD. According to the present invention, the electric charge generated in the charge transfer path of the CCD during exposure of the CCD is transferred and lost by driving the charge transfer path at a low frequency by the driving means. During exposure, it is possible to effectively prevent noise from being generated in an image due to charges accumulated in the charge transfer path of the CCD. In a preferred embodiment of the present invention, the imaging device further includes power control means for reducing power supplied to an output amplifier of the CCD when the CCD is exposed.

According to a preferred embodiment of the present invention, CC
At the time of exposure of a CCD which does not need to supply power to the output amplifier of D, the power supplied to the output amplifier of the CCD is reduced by the power control means. Even if it increases, it becomes possible to reduce image noise caused by the heat generated by the CCD. In a further preferred aspect of the present invention, the power control means is configured not to supply power to the output amplifier when the CCD is exposed. According to a further preferred embodiment of the present invention, it is possible to further suppress heat generation of the CCD.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic front view of an image generation device including an imaging device according to a preferred embodiment of the present invention. In FIG. 1, the image generation device includes an imaging device 1, a dark box 2, and a personal computer 4. As shown in FIG. 1, the personal computer 3 includes a CRT 4 and a keyboard 5. FIG. 2 is a schematic vertical sectional view of the imaging device 1. As shown in FIG. 2, the imaging device 1 includes a CCD 6
And a heat transfer plate 7 made of metal such as aluminum
A Peltier element 8 for cooling the CCD 6, and a CC
A shutter 9 arranged in front of D6, an A / D converter 10 for converting analog image data generated by the CCD 6 into digital image data, and temporarily storing the image data digitized by the A / D converter 10. An image data buffer 11 for storing and a CP for controlling the operation of the imaging device 1
U12. An opening formed between the dark box 2 and the dark box 2 is closed by a glass plate 13, and a radiation fin 14 for radiating heat generated by the Peltier element 8 is provided around the imaging device 1 in the longitudinal direction. It is formed over half.

[0008] An image intensifier 15 arranged in the dark box 2 is provided on the front surface of the glass plate 13 provided in the imaging device 1, and a camera lens 16 is provided on the front surface of the image intensifier 15. Installed. FIG. 3 is a schematic vertical sectional view of the dark box 2. As shown in FIG. 3, a first blue LED light source 21 that emits excitation light having a light emission wavelength center of 450 nm is provided in the dark box 2. Second blue LE emitting excitation light having an emission wavelength center of 450 nm
A D light source 22 and a third blue LED light source 23 are provided. A filter 24 is attached to the upper surface of the first blue LED light source 21, and a filter 25 and a filter 26 are attached to the front surfaces of the second blue LED light source 22 and the third blue LED light source 23, respectively. ing. The filters 24, 25, and 26 have a property of cutting off light harmful to excitation of a fluorescent substance other than a wavelength of around 450 nm and transmitting only light of a wavelength of around 450 nm. On the front surface of the camera lens 16, a filter 27 that cuts off excitation light near 450 nm is provided detachably.

FIG. 4 is a block diagram around the personal computer 3. As shown in FIG. 4, the personal computer 3 includes a CPU 30 that controls exposure of the imaging device 1, an image data transfer unit 31 that reads image data generated by the imaging device 1 from the image data buffer 11, Image processing means 33 for performing image processing on the image data read by the means 31 and storing the image data in the image data storage means 32; and a CRT based on the image data stored in the image data storage means 32.
And image display means 34 for displaying a visible image on the screen of No. 4. First blue LED light source 21, second blue L
The ED light source 22 and the third blue LED light source 23 are controlled by a light source control unit 35.
Is configured to receive an instruction signal from the keyboard 5 via the CPU 30. The CPU 30
Various signals can be output to the CPU 12 of the imaging device 1.

FIG. 5 is a block diagram around the CCD 6. As shown in FIG. 5, the CCD 6 includes a photoelectric sensor 60 and an output amplifier 62, and the charges accumulated in the photoelectric sensor 60 pass through a charge transfer path 64
It is configured to be sent to the output amplifier 62 and output. The transfer of the charge from the charge transfer path 64 is controlled by the read control circuit 66, and the output amplifier 60
Power is supplied from the output amplifier power supply circuit 68. The read control circuit 66 and the output amplifier power supply circuit 65
It is controlled by the CPU 12. In this embodiment, even when the photoelectric sensor 60 is exposed, the CPU 12 drives the charge transfer path 64 so that the charge is output from the output amplifier 62.
The read control circuit 66 is controlled so that
The output amplifier power supply circuit 68 is controlled so that the power supplied to the output amplifier 60 decreases.

The image generating apparatus according to the present embodiment detects fluorescence from an image carrier carrying an image of a fluorescent substance and chemiluminescence generated by contact between the chemiluminescent substance and the labeling substance, and detects the fluorescent image and the chemiluminescence. It is configured to generate an image, and detects fluorescence from an image carrier carrying an image of a fluorescent substance to generate a visible image as described below. Here, the image carrier carries an image of a fluorescent substance means that the image carrier carries an image of a sample labeled with a fluorescent dye, and that the enzyme is combined with the labeled sample before the enzyme is fluoresced. Contacting with a substrate to change the fluorescent substrate into a fluorescent substance that emits fluorescence, and carrying an image of the obtained fluorescent substance. First, the user places a sample image carrier 18 on the filter 24.
Is placed, focus is performed, and after the dark box 2 is closed, when the user inputs an exposure start signal to the keyboard 5, the light source control means 35 causes the first blue LED
The light source 21 or the second blue LED light source 22 and the third blue LED light source 23 are turned on, and the excitation light is emitted toward the image carrier 18. At the same time, the exposure start signal
The image is input to the CPU 12 of the imaging apparatus 1 via the CPU 30, and the shutter 9 is opened by the CPU 12 so that the CCD 6
The exposure of the photoelectric sensor 60 is started. Upon receiving the exposure start signal, the CPU 12 simultaneously reads the read control circuit 6
6 outputs a low-frequency drive signal to drive the charge transfer path 64 at a low frequency to transfer charges to the output amplifier 62, and outputs a power control signal to the output amplifier power supply circuit 68 to output the power control signal. From the amplifier power supply circuit 68 to the output amplifier 62
Reduce the power supplied to the

Excitation light emitted from the first blue LED light source 21 or the second blue LED light source 22 and the third blue LED light source 23 is filtered by filters 24, 25, and 26 except for light having a wavelength near 450 nm. The wavelength component is cut, and as a result, the fluorescent substance in the image carrier 18 is excited by light having a wavelength of about 450 nm, and emits fluorescence. The fluorescence emitted from the fluorescent substance in the image carrier 18 is
The light enters the photoelectric surface of the image intensifier 15 via the filter 27 and the camera lens 16 and is amplified to form an image on the fluorescent surface of the image intensifier 15. The photoelectric sensor 60 of the CCD 6 receives the light of the image thus formed on the phosphor screen of the image intensifier 15 and accumulates the light in the form of electric charges. Since the filter 27 cuts off the excitation light having a wavelength near 450 nm, only the fluorescent light emitted from the fluorescent substance in the image carrier 18 is emitted by the photoelectric sensor 60 of the CCD 6.
Is received by the

When a predetermined exposure time has elapsed, the CPU 30
Outputs an exposure completion signal to the CPU 12 of the imaging device 1. Upon receiving the exposure completion signal from the CPU 30, the CPU 12 outputs a high-frequency drive signal to the readout control circuit 66, drives the charge transfer path 64 at a high frequency, and transfers the charge accumulated by the photoelectric sensor 60 to the charge transfer circuit. Via road 64,
The signal is transferred to the output amplifier 62. At the same time, the CPU 12
A power control signal is output to the output amplifier power supply circuit 66 to transfer the power supplied from the output amplifier power supply circuit 66 to the output amplifier 64, and the output amplifier 64 transfers the analog image data accumulated by the photoelectric sensor 60 in the form of electric charge. The power is increased to a possible level, and the analog image data accumulated by the photoelectric sensor 60 in the form of electric charges is transferred to the A / D converter 10, digitized, and temporarily stored in the image data buffer 11. At the same time, the CPU 30
1 to read out the digital image data temporarily stored in the image data buffer 11 of the image pickup apparatus 1 and input the digital image data to the image processing means 33. The image processing unit 33 performs image processing on the image data input from the image data transfer unit 31,
Store it in 2.

Thereafter, when the user inputs an image generation signal to the keyboard 5, the image display means 35 reads the image data stored in the data storage means 33, and based on the read image data, the CRT 4 A fluorescent image is displayed on the screen. When generating a chemiluminescent image, the filter 27 is removed, and the first blue LED light source 21, the second blue LED light source 22, and the third blue LED
Each of the ED light sources 23 is kept in the off state, and the filter 2
4 except that a sample 18 that emits chemiluminescence is placed thereon and the chemiluminescence emitted from the sample 18 is detected.
Sample 1 was prepared in exactly the same way as when the fluorescent image was generated.
Chemiluminescence emitted from the CCD 6 through the camera lens 16 and the image intensifier 15
The photoelectric sensor 60 photoelectrically detects the image, generates image data, and displays a chemiluminescent image on the screen of the CRT 4.

While the photoelectric sensor 60 receives light and accumulates electric charges, electric charges are generated and accumulated in the electric charge transfer path 64, and the electric charges may cause noise in an image. However, according to the present embodiment, upon receiving the exposure start signal, the CPU 12 outputs a low-frequency drive signal to the readout control circuit 66 to drive the charge transfer path 64 at a low frequency to transfer the charge. Since the light is transferred to the output amplifier 62, even if the photoelectric sensor 60 is exposed for a long period of time, the light reception of the photoelectric sensor 60 is completed even if the photoelectric sensor 60 is exposed for a long time to detect extremely weak light such as chemiluminescence or fluorescence. Sensor 60
Transfer analog image data accumulated in the form of charges to the A / D converter 10 via the charge transfer path 64 and the output amplifier 66, and generate an image based on the converted digital image data. In addition, it is possible to prevent noise due to charges generated in the charge transfer path 64 from being generated in an image while the photoelectric sensor 60 receives light. Further, according to the present embodiment, when the exposure start signal is received, C
The PU 12 outputs a power control signal to the output amplifier power supply circuit 68, and outputs the power control signal from the output amplifier power supply circuit 68 to the output amplifier 62.
Since the power supplied to the CCD 6 is reduced, even if the photoelectric sensor 60 of the CCD 6 is exposed for a long time to detect extremely weak light such as chemiluminescence or fluorescence, CC
It is possible to prevent noise from occurring in the image due to the heat generated by D6. Further, upon receiving the exposure completion signal, the CPU 12 outputs a power control signal to the output amplifier power supply circuit 65 to generate power for transferring the analog image data accumulated by the photoelectric sensor 60 of the CCD 6 in the form of electric charge. From the output amplifier power supply circuit 65 to the output amplifier 6
0, so that even if the CCD 6 having a very large number of pixels is used in order to obtain a high quality image,
Image data can be read at high speed.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing. For example, in the above embodiment, when the photoelectric sensor 60 receives light, C
PU 12 is connected to output amplifier 6 from output amplifier power supply circuit 65.
Although the power supplied to the A / D converter 10 is controlled to be reduced, the A / D converter 10 may operate the output amplifier 60 to transfer the analog image data to the A / D converter 10.
If the converter 10 is controlled so as not to be digitized, the output amplifier 60 may be operated. Further, in the embodiment, when the photoelectric sensor 60 receives light, C
PU 12 is connected to output amplifier 6 from output amplifier power supply circuit 65.
Although the control is performed so as to reduce the power supplied to 0, when the exposure operation of the photoelectric sensor 60 is not affected,
At the time of light reception by the photoelectric sensor 60, control can be performed so that power is not supplied from the output amplifier power supply circuit 65 to the output amplifier 60.

Further, in the above embodiment, the image intensifier 15 is provided on the front surface of the imaging device 1, but it is not always necessary to provide the image intensifier 15. In the embodiment, the first blue LED light source 21, the second blue LED light source 22, and the third blue LED light source 23 are provided in the dark box 2.
Is provided, but only the first blue LED light source 21 or the second blue LED light source 22 and the third blue LE
Only the D light source 23 may be provided. Further, in the above embodiment, the blue LED light sources 21, 22, and 23 that emit excitation light having a light emission wavelength center of 450 nm are used.
LED that emits excitation light having a wavelength of 0 nm to 700 nm
The light source can be selected and used.

In the above embodiment, when an exposure start signal is input to the keyboard 5, the light source control means 36 controls the first blue LED light source 21 or the second blue LED light source 22 and the third blue LED light source 23. Is turned on, but it is not always necessary to configure the light source control means 36 to be controlled by the personal computer 3, and the light source control means 36 may be manually operated. Furthermore, in the above-described embodiment, the image generating apparatus is configured such that the filter 27 that cuts off the excitation light near 450 nm is detachable, and by removing the filter 27, extremely weak chemiluminescence is detected and the chemical light is detected. Although it is configured to be able to generate a light emission image, the filter 27
6 may be fixedly provided on the front surface and may be configured to generate only a fluorescence image in the fluorescence detection system.

In the above embodiment, the first blue LED light source 21, the second blue LED light source 22, and the third blue LED light source 23 are provided. When used as an image generation device that generates only the first blue LED light source 21, the second blue LED light source 22, and the third blue LED light source 23
Are unnecessary, and the filters 24, 25, 26, 27
There is no need. Further, in the above embodiment, the radiation fins 14 for dissipating the heat generated by the Peltier element 8 are formed around the imaging device 1 over almost half of the longitudinal direction, but over the entire longitudinal direction. The radiation fins 14 may be provided, and the extent to which the radiation fins 14 are provided around the imaging device 1 can be arbitrarily determined.

In the present invention, means does not necessarily mean physical means, but also includes a case where the function of each means is realized by software. Further, the function of one unit may be realized by two or more physical units, or the function of two or more units may be realized by one physical unit.

[0021]

According to the present invention, it is possible to provide an imaging apparatus having a CCD and capable of obtaining an image with high sensitivity even when exposed for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an image generation device including an imaging device according to a preferred embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of the imaging apparatus.

FIG. 3 is a schematic vertical sectional view of a dark box.

FIG. 4 is a block diagram of the periphery of a personal computer.

FIG. 5 is a block diagram around a CCD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image pickup device 2 Dark box 3 Personal computer 4 CRT 5 Keyboard 6 CCD 7 Heat transfer plate 8 Peltier element 9 Shutter 10 A / D converter 11 Image data buffer 12 CPU 13 Glass plate 14 Heat radiation fin 15 Image intensifier 16 Camera lens Reference Signs List 18 Sample 21 First blue LED light source 22 Second blue LED light source 23 Third blue LED light source 24, 25, 26 Filter 27 Filter 30 CPU 31 Image data transfer means 32 Image data storage means 33 Image processing means 34 Image display Means 35 Light source control means 60 Photoelectric sensor 62 Output amplifier 64 Charge transfer path 66 Readout control circuit 68 Output amplifier power supply circuit

Claims (3)

[Claims] 1. An imaging apparatus, comprising: a driving unit for driving a charge transfer path of a CCD (Charge Coupled Device) at a low frequency during exposure of the CCD. 2. The imaging apparatus according to claim 1, further comprising a power control unit configured to reduce power supplied to an output amplifier of the CCD when the CCD is exposed. 3. The imaging apparatus according to claim 2, wherein the power control unit is configured not to supply power to an output amplifier of the CCD when the CCD is exposed.