JP2004343195A - Radiation resistant camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation resistant camera, an imaging element of which is hardly affected by gamma rays. <P>SOLUTION: The radiation resistance camera wherein the surrounding of the imaging element is covered by a fast neutron shield member is characterized in to include: a gamma ray shield member located around the imaging element except on an optical axis of a lens; and an imaging element movement mechanism for moving the imaging element to a first position facing an opening of the gamma ray shield member on the optical axis of the lens in the case of photographing, and linearly moving the imaging element backward to a second position on the optical axis of the lens and thereafter turning and moving the imaging element to a third position behind the gamma ray shield member in the case of non-photographing state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a video camera using an image sensor, and more particularly to a radiation-resistant camera having a function of protecting an image sensor from γ-rays, which is used as a television camera or a surveillance camera used in a radiation environment.
[0002]
[Prior art]
Generally, an image sensor is damaged when irradiated with fast neutrons. Therefore, in a conventional radiation-resistant camera, a high-speed neutron shielding material is arranged around the image sensor to prevent the high-speed neutrons from directly hitting the image sensor, thereby improving the life of the image sensor (for example, Patent Document 1). reference).
[0003]
[Patent Document 1]
JP 2000-321394 A
[Problems to be solved by the invention]
Conventional radiation-resistant cameras are hardly affected by high-speed neutrons because the surroundings of the image sensor are covered with high-speed neutron shielding material. In this case, there is a problem in that the image pickup element is rapidly deteriorated due to the influence of γ-rays.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to obtain a radiation-resistant camera in which an image sensor is hardly affected by gamma rays.
[0006]
[Means for Solving the Problems]
A radiation-resistant camera according to the present invention is a radiation-resistant camera in which the periphery of an imaging element is covered with a high-speed neutron shielding material, wherein a gamma ray shielding material provided around the imaging element except on the optical axis of the lens is provided. At the time, the image sensor is moved to the first position on the optical axis of the lens facing the opening of the γ-ray shielding material. At the time of non-imaging, the image sensor is moved straight to the second position on the optical axis of the lens. And an image pickup device moving mechanism for rotating and retreating to a third position where it is shadowed by the γ-ray shielding material.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 to 7 show the first embodiment. FIG. 1 is an external perspective view of a CCD camera viewed from the front side, FIG. 2 is an external perspective view of the CCD camera viewed from the back side, and FIG. FIG. 4 is a sectional view showing a CCD camera, FIG. 5 is a perspective view showing an image pickup device moving mechanism of the CCD camera, FIG. 6 is a sectional view showing an image pickup device moving mechanism of the CCD camera, and FIG. 7 is a CCD camera. FIG. 2 is a schematic diagram showing an image pickup device moving mechanism of FIG.
[0008]
As shown in FIGS. 1 and 2, the CCD camera 1 includes a camera case 2 forming an outer shell, a front panel 3 made of a neutron moderator and forming a front surface, and a camera unit 4 having an image sensor described later. , Front panel 3 and camera unit 4 are detachably fixed to camera case 2 by latch 5.
[0009]
As shown in FIG. 3, the front panel 3 and the camera unit 4 have a structure that can be easily removed by releasing the latch 5. A lens 6 is fixed to the camera unit 4, and a power / control connector 7 and a video connector 8 are attached to the camera unit 4. By connecting cables to them, power is supplied to the camera. , Control of the camera, and extraction of the video signal.
[0010]
As shown in FIG. 4, an image sensor 9 and a camera substrate 10 are attached to the camera unit 4. The image sensor 9 has a property of being deteriorated by irradiation with neutron rays and γ rays. In addition, some electronic components mounted on the camera substrate 10 have characteristics that deteriorate when irradiated with γ-rays. For this reason, in the CCD camera 1 of the present invention, which is intended to be used in a radiation environment, it is necessary to protect the imaging device 9 from neutron rays and γ rays and protect the camera substrate 10 from γ rays.
[0011]
For this reason, the neutron moderators 11 to 14 are mounted inside the camera case 2. A neutron moderator 16 is also attached to the camera unit 4 behind the image sensor 9. The front panel 3 is also made of a neutron moderator. When the camera unit 4 and the front panel 3 are attached to the camera case 2, the image sensor 9 has a structure in which the entire periphery is covered with the neutron moderator.
[0012]
In addition, γ-ray shielding members 17 and 19 are attached around the imaging element 9. Therefore, the image sensor 9 is protected from external neutrons and gamma rays.
A gamma ray shielding member 18 is attached around the camera substrate 10 to protect the camera substrate 10 from gamma rays.
[0013]
By the way, since the γ-ray shielding member 19 cannot be made transparent, the γ-ray shielding member cannot be arranged in the front direction of the image sensor 9 or in the direction in which light from the lens 6 is incident. Therefore, in the CCD camera 1 of the present invention, only when power is supplied, the imaging device 9 is moved to a regular position on the optical axis of the lens 6 (the position in FIG. 5 = first position) to perform photographing. An imaging element moving mechanism 20 that retracts behind the γ-ray shielding member 19 (third position) when not supplied is employed.
[0014]
The image sensor moving mechanism 20 will be described with reference to FIGS. When the power is not turned on, the CCD substrate 32 is retracted behind the γ-ray shielding material (third position). When the power is turned on in this state, the solenoid 21 and the motor 22 are energized, and the gear plate 23 is rotated by the rotation of the motor 22 shaft. When the projection 23a of the gear plate 23 and the latch 24 mesh with each other, the gear plate 23 stops rotating at that position, and the rotation of the motor 22 is transmitted to the gears A25, B26, and C27 to linearly move the rack 28.
[0015]
Then, since the driving pin 29 fixed to the rack 28 and the cylindrical cam 30 are engaged with each other, the cylindrical cam 30 guided by the guide rod 31 rotates first, and the CCD substrate 32 fixed to the cylindrical cam 30 turns the γ-ray. From behind the shielding member, it rotates and moves to a position on the optical axis (second position).
[0016]
Next, the drive pin 29 pushes the cylindrical cam 30 toward the lens 6 via the sleeve 34 and the spring 35, and the cylindrical cam 30 is guided by the guide rod 31 and linearly moves. Before the rack 28 stops, the cylindrical cam 30 hits the flange back adjustment screw 36 and stops (first position).
[0017]
The rack 28 continues to move further, and the spring 35 is compressed via the sleeve 34 by the drive pin 29. When the rack 28 advances to the home position, the current of the motor 22 is cut off by the limit switch 37, and the rack 28 stops. In this state, the imaging element 9 is on the optical axis of the lens 6, and the distance in the optical axis direction is also determined.
[0018]
Next, when the power supply of the camera unit 4 is turned off, the current of the solenoid 21 is cut off, so that the latch 24 is disengaged from the projection 23a of the gear plate 23, and the gear plate 23 can freely rotate. Then, the gear B26 and the gear C27 are disengaged from each other, and the rack 28 is pushed back by the return spring 38. Then, the cylindrical cam 30 is linearly moved in the opposite direction to the lens 6 by the drive pin 29 (second position), and then rotationally moved and retracts behind the γ-ray shielding member 19 (third position).
[0019]
The operation of the image pickup device moving mechanism will be described in more detail with reference to schematic diagrams.
In FIG. 7, a cylindrical cam 30 has a cylinder developed in a plane. Therefore, the vertical movement of the cylindrical cam 30 in the drawing actually indicates a rotational movement about the guide rod 31 (not shown), and the left and right movement indicates a linear movement in a direction parallel to the guide rod 31. The cylindrical cam 30 has two grooves, a groove A30a formed obliquely to the axis of the cylinder and an L-shaped groove B30b cut in the circumferential direction and the axis parallel direction. 29 and the fixing pin 39 are fitted. The rack 28 performs a linear motion in the left-right direction by the rotation of the gear C27.
[0020]
FIG. 7A shows a state in which power is not supplied, and shows a third position where the imaging element 9 is retracted behind the γ-ray shielding member 19. When the gear C27 is rotated leftward from this state, the rack 28 linearly moves leftward.
[0021]
Then, while the drive pin 29 fixed to the rack 28 is engaged with the groove A30a of the cylindrical cam 30, the fixed pin 39 and the circumferential groove of the groove B30b are engaged with each other, so that the cylindrical cam 30 linearly moves leftward. Is limited, and the groove A30a is cut obliquely with respect to the axis of the cylinder, so that the cylindrical cam 30 rotates in the + direction in the figure.
[0022]
When the cylindrical cam 30 rotates and the fixing pin 39 reaches the bending point of the L-shaped groove B30b, the rotational movement of the cylindrical cam 30 is restricted by the groove cut in the direction parallel to the axis of the groove B30b. Then, since the linear movement to the left is enabled, the cylindrical cam 30 starts the linear movement to the left (FIG. 7B).
[0023]
The cylindrical cam 30 further continues the linear motion and stops upon hitting the flange back adjustment screw 36 (FIG. 7C). In this state, photographing becomes possible (first position).
[0024]
Next, when the gear C27 is rotated rightward, the rack 28 starts linearly moving rightward, and the cylindrical cam 30 linearly moves rightward (FIG. 7D).
[0025]
Further, when the rack 28 moves rightward, the fixing pin 39 reaches the bending point of the L-shaped groove B30b, and the cylindrical cam 30 stops linear movement and starts rotating in the negative direction (FIG. 7 (e). )).
[0026]
When the cylindrical cam 30 further rotates, the fixing pin 39 reaches the end of the circumferential groove of the groove B30b, and the cylindrical cam 30 stops rotating (FIG. 7F).
[0027]
As described above, in the imaging device moving mechanism 20 according to the present invention, two grooves A30a formed obliquely with respect to the axis of the cylinder, and an L-shaped groove B30b cut in the circumferential direction and the axis parallel direction. By using the cylindrical cam 30 having a groove, the linear movement of the rack 28 is converted into rotation and linear movement. In the non-shooting mode, the image pickup device 9 is linearly retracted to the second position on the optical axis of the lens 6, and then rotated to move to the first position facing the portion. The operation of retracting to the third position corresponding to the shadow of the line shielding material is realized with a simple structure.
[0028]
Embodiment 2 FIG.
FIG. 8 shows the second embodiment and is a schematic diagram showing an image pickup device moving mechanism of a CCD camera. As shown in the figure, the cylindrical cam 30 has two grooves, a groove A30a formed obliquely to the axis of the cylinder and an L-shaped groove B30b cut in the circumferential direction and the axis parallel direction. And are fitted with the driving pin 29 and the fixing pin 39, respectively.
[0029]
R31C is formed at the bending point of the L-shaped groove B30b. When the rack 28 moves at high speed, the fixing pin 39 collides with the side wall of the groove B30b at the bending point of the L-shaped groove B30b, and an impact is generated. However, since the R31c is provided at the bending point of the groove, There is a feature that the shock can be reduced by smoothly connecting the linear motion and the rotary motion.
[0030]
Embodiment 3 FIG.
FIG. 9 shows the third embodiment and is a schematic view showing an image pickup device moving mechanism of a CCD camera. As shown in the figure, the cylindrical cam 30 has two grooves, a groove A30a formed obliquely to the axis of the cylinder and an L-shaped groove B30b cut in the circumferential direction and the axis parallel direction. And are fitted with the driving pin 29 and the fixing pin 39, respectively.
[0031]
The groove A30a is provided with a dent 30d at one end (the side where the rack 28 linearly moves from the third position and the drive pin 29 contacts). Further, as in the second embodiment, R is formed at a bending point of the L-shaped groove B30b.
[0032]
FIG. 9A shows the third position. When the gear C27 is rotated leftward from this state, the rack 28 linearly moves leftward. Then, the cylindrical cam 30 rotates in the + direction. When the cylindrical cam 30 rotates and the fixing pin 39 reaches the bending point of the groove B30b, the cylindrical cam 30 starts a linear motion to the left (FIG. 9B).
[0033]
The cylindrical cam 30 further continues the linear motion and stops upon hitting the flange back adjustment screw 36 (FIG. 9C). In this state, photographing becomes possible (first position).
[0034]
Next, when the gear C27 is rotated rightward, the rack 28 starts linearly moving rightward, and the cylindrical cam 30 linearly moves rightward with the driving pin 29 fitted in the recess 30d of the groove A30a ( FIG. 9D).
[0035]
Further, when the rack 28 moves to the right, the fixing pin 39 reaches the bending point of the L-shaped groove B30b, and the fixing pin 39 is engaged with R30c of the groove B30b, so that the cylindrical cam 30 starts rotating to drive. The pin 29 is disengaged from the recess 30d of the groove A30a, and the rack 28 further linearly moves rightward, so that the cylindrical cam 30 keeps rotating (FIG. 9E).
[0036]
When the cylindrical cam 30 further rotates, the fixing pin 39 reaches the end of the groove B30b, and the cylindrical cam 30 stops rotating (FIG. 9F).
[0037]
When there is no dent 30d in the groove A30a, in the stroke of FIG. 9D, the cylindrical cam 30 linearly moves rightward while the drive pin 29 is pressed against the slope of the groove A30a. During this operation, a rotational force is applied to the cylindrical cam 30, and the fixing pin 39 is pressed against the side wall of the groove B30b to generate friction. Since the cylindrical cam 30 moves linearly in the combined state, there is a feature that a rotating force is not applied to the cylindrical cam 30 and the driving force in the stroke (d) is small.
[0038]
【The invention's effect】
The radiation-resistant camera according to the present invention includes a γ-ray shielding member provided around the imaging element except on the optical axis of the lens, and a γ-ray shielding member on the optical axis of the lens during imaging. It moves to the first position facing the opening, and when non-photographing, the image sensor is receded linearly to the second position on the optical axis of the lens, and then rotated to move the shadow of the γ-ray shielding material. And an image pickup device moving mechanism for retracting the image pickup device to the third position. Therefore, it is possible to obtain a radiation-resistant camera in which the image pickup device is hardly affected by γ-rays.
[Brief description of the drawings]
FIG. 1 shows the first embodiment, and is an external perspective view of a CCD camera viewed from the front side.
FIG. 2 is a view showing the first embodiment, and is an external perspective view of the CCD camera viewed from the back side.
FIG. 3 shows the first embodiment, and is an exploded perspective view showing a CCD camera.
FIG. 4 shows the first embodiment, and is a cross-sectional view showing a CCD camera.
FIG. 5 is a view showing the first embodiment, and is a perspective view showing an image pickup device moving mechanism of the CCD camera.
FIG. 6 shows the first embodiment, and is a cross-sectional view showing an image pickup device moving mechanism of the CCD camera.
FIG. 7 is a view showing the first embodiment, and is a schematic view showing an image pickup device moving mechanism of the CCD camera.
FIG. 8 is a view showing the second embodiment, and is a schematic view showing an image pickup device moving mechanism of the CCD camera.
FIG. 9 shows the third embodiment and is a schematic diagram showing an image pickup device moving mechanism of a CCD camera.
[Explanation of symbols]
Reference Signs List 1 CCD camera, 2 camera case, 3 front panel, 4 camera units, 5 latches, 6 lenses, 7 power / control connector, 8 video connector, 9 image sensor, 10 camera board, 11-14, 16 neutron moderator , 17 to 19 γ-ray shielding material, 20 imaging element moving mechanism, 21 solenoid, 22 motor, 23 gear plate, 23a projection, 24 latch, 25 gear A, 26 gear B, 27 gear C, 28 rack, 29 drive pin, 30 cylindrical cam, 30a groove A, 30b groove B, 30c R, 30d recess, 31 guide rod, 32 CCD board, 33 frame, 34 sleeve, 35 spring, 36 flange back adjustment screw, 37 limit switch, 38 return spring, 39 Fixing pin.

Claims (4)

In a radiation-tolerant camera with a high-speed neutron shielding material surrounding the image sensor,
Around the image sensor, a γ-ray shielding material provided except on the optical axis of the lens,
At the time of photographing, the image sensor is moved to a first position on the optical axis of the lens facing the opening of the γ-ray shielding material, and at the time of non-photographing, the image sensor is moved along the optical axis of the lens. An image pickup device moving mechanism that linearly retreats to the second position, and then rotates and retreats to a third position that becomes a shadow of the γ-ray shielding material;
A radiation resistant camera comprising: The imaging device moving mechanism,
Driven by a driving device, linearly moved, and a rack to which a driving pin is fixed;
A frame provided with fixing pins,
A groove A to which the image pickup device is fixed and which is fitted to the drive pin and formed obliquely with respect to a cylindrical axis, and an L-shaped groove B which is fitted to the fixed pin and cut in a circumferential direction and an axis parallel direction. And a cylindrical cam with
A guide rod for guiding the cylindrical cam in a straight line and a rotating direction;
When the rack starts linear movement from the third position, the fixing pin and the circumferential portion of the L-shaped groove B are fitted to limit the linear movement, and the drive pin is When the fixed cam reaches the bending point of the L-shaped groove B, it reaches the second position. 2. The radiation hardened camera according to claim 1, wherein a directional portion is linearly moved by the fixing pin and reaches the first position to be in a photographable state. 3. The radiation resistant camera according to claim 2, wherein a bending point of the L-shaped groove B has an R shape. 3. The radiation-resistant camera according to claim 2, wherein the rack moves linearly from the third position of the groove A, and a recess is provided at an end of the groove A on which the drive pin contacts. 4. .

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