JP3803274B2 - CCTV camera lens diaphragm device and diaphragm device unit - Google Patents

Description

[0001]
【Technical field】
The present invention relates to an aperture device for a CCTV (surveillance camera system) lens equipped with an optical filter such as an infrared cut filter. Furthermore, the present invention relates to a lens diaphragm device for a day and night surveillance camera system that can be practically used from a visible light wavelength range (about 400 to 700 nm) to a near infrared wavelength range (about 700 to 1000 nm).
[0002]
[Prior art and its problems]
As a day-and-night monitoring camera system, color light is imaged on the color image sensor (CCD) of the camera body during the daytime, and in the near-infrared light region in addition to the visible light region at night. There is known a system in which light is imaged and monochrome photography is performed and a monitoring image is displayed on a TV monitor. In this system, during daytime shooting, a near-infrared cut filter is positioned in front of the image sensor (inside the body or lens barrel), and color shooting is performed based only on light in the visible wavelength range. During monochrome photography at night, the filter is removed from the front of the image sensor, and light in the infrared wavelength range and visible wavelength range is detected as a monochrome image.
[0003]
FIGS. 9A and 9B are diagrams showing the configuration of a conventional CCTV camera provided with an infrared cut filter. The infrared cut filter 22 is provided in the camera body 10 as shown in FIGS. 9 (a) and 9 (b). In FIG. 9A, since the infrared cut filter 22 is disposed on the optical path, the light incident on the lens barrel 18 enters the camera body 10 via the aperture device 21 ′, and the infrared force filter 22 And reaches the CCD 11 and is projected as a subject image. On the other hand, in FIG. 9B, since the infrared cut filter 22 is removed from the optical path, when the light incident on the lens barrel 18 enters the camera body 10 via the aperture device 21 ′, the infrared cut filter The image is projected onto the CCD 11 without going through 22. The aperture device 21 ′ in the lens barrel 18 is driven by an aperture actuator 24 such as a galvanometer provided in the lens barrel 18 to adjust the size of the opening. On the other hand, the infrared cut filter 22 in the camera body 10 is driven by an infrared cut filter actuator 25 ′ such as a motor provided in the camera body 10, and light is transmitted as shown in FIGS. 9 (a) and 9 (b). It is arranged on the axis L or removed from the optical axis L.
[0004]
However, in a CCTV camera or the like in which the camera body 10 and the lens barrel 18 are integrated, it is difficult to provide a unit for an infrared cut filter in the camera body because the camera body itself is small.
[0005]
In addition, in a conventional diaphragm device, a configuration in which an ND filter positioned on the diaphragm aperture is attached to the diaphragm blades in order to widen the light intensity control range during night monochrome photography without the infrared cut filter 22 inserted. It has been. However, the conventional ND filter is in a state where the transmittance with respect to infrared light is increased, that is, a so-called missing state. An example of the spectral transmittance characteristics of this conventional ND filter is shown in FIG. With such an ND filter having spectral transmittance characteristics, the total amount of light including visible light and infrared light during monochrome photography cannot be suppressed uniformly, and the amount of infrared light transmitted is larger than that of visible light. . As a result, the subject portion where infrared light is strongly reflected appears bright, making the image difficult to see.
[0006]
OBJECT OF THE INVENTION
An object of the present invention is to obtain a small aperture device for a CCTV camera lens in which a diaphragm and an optical filter mechanism are provided in a lens barrel based on the above problem awareness. Another object of the present invention is to obtain an aperture device that can regulate the amount of transmitted light up to infrared light during night photography.
[0007]
Summary of the Invention
The CCTV camera lens diaphragm device of the present invention is a CCTV. Camera A diaphragm provided in the lens barrel; a flat-plate-shaped diaphragm unit substrate for holding the diaphragm; diaphragm driving means for adjusting the size of the aperture of the diaphragm; and light in the infrared region. An infrared cut filter for blocking, and a filter driving means for inserting / removing the infrared cut filter into / from the optical path, Is It has two blades, and in the light transmitting part that forms the aperture opening, the blade has a transmittance in the infrared region that is almost equal to or less than or equal to the transmittance in the visible light region, or blocks light in the infrared region. An ND filter having spectral transmittance characteristics is provided, the diaphragm and the infrared cut filter are disposed along the diaphragm unit substrate, and the diaphragm, the diaphragm unit substrate, the diaphragm driving means, and the infrared All of the cut filter and the filter driving means But Placed in the lens barrel The CCTV camera adjusts the amount of light by driving the diaphragm driving means, and inserts the infrared cut filter into the optical path during daylight shooting to shoot color images, and lights the infrared cut filter during night shooting. Retract from the street and shoot in monochrome It is characterized by that.
[0008]
The diaphragm has two diaphragm blades, and the optical filter is provided in at least one opening of a flat plate-shaped filter fixing plate having two openings, and the two diaphragm blades and the filter fixing plate are respectively provided as diaphragm unit substrates. It is preferable to arrange along the first and second surfaces. As a result, the diaphragm device can be made thinner and smaller.
[0009]
The filter driving means preferably includes a latching mechanism for holding the position of the optical filter when the optical filter is inserted on the optical path and the position of the optical filter when the optical filter is removed from the optical path. . As a result, the position of the optical filter can be held by the latching mechanism except when the filter driving means is driven to insert and remove the filter, so that the power consumption of the filter driving means (actuator) can be reduced. it can.
[0010]
In order to improve the durability of the diaphragm device, reduce the cost, simplify the circuit configuration, and further reduce the size, it is preferable to use a galvanometer for the filter driving means.
[0011]
Specifically, the optical filter is an infrared cut filter that blocks light from the infrared castle. The infrared castle is a wavelength region having a wavelength of about 700 nm to 1000 nm.
[0012]
In addition, the above ND The surface reflectance of the filter is preferably about 2% or less.
[0013]
According to another aspect of the present invention, there is provided an aperture unit unit provided in a lens barrel of a CCTV camera having a color image sensor, the aperture unit substrate having a flat plate portion having an imaging aperture, and the imaging aperture. A pair of corresponding openings is provided, and an infrared cut filter for blocking light in the infrared region is provided in one of the openings and moved to one of the front and back surfaces of the flat plate portion of the unit substrate. A filter fixing plate that is supported in a movable manner, two diaphragm plates that are movably supported on the other surface of the flat plate portion, and change the size of the aperture opening that overlaps the photographing aperture according to the relative movement position, and Spectral transmittance characteristics that are affixed to at least one of the two diaphragm plates so as to be positioned above the aperture, and whose transmittance in the infrared region is substantially the same as or less than that in the visible light region, or red Block light from outside area A ND filter having a light transmittance characteristic in the stop unit substrate is supported by sandwiching the flat plate portion The filter fixing plate Actuator for infrared cut filter that reciprocally moves a pair of apertures and positions them on the imaging aperture When , A diaphragm drive actuator that changes the diaphragm aperture by relatively moving the two diaphragm plates in opposite directions. The diaphragm drive actuator is driven to adjust the amount of light, and at the time of daylighting, the infrared cut filter actuator is driven to open the aperture where the infrared cut filter is mounted. In the color shooting, the infrared cut filter actuator is driven and the other of the pair of apertures is positioned in the shooting aperture during the night shooting. It is characterized by that. The infrared region is a wavelength region having a wavelength of about 700 nm to 1000 nm.
[0014]
When a filter having a spectral transmittance characteristic in which the transmittance in the infrared region is approximately equal to or less than or equal to the transmittance in the visible light region or a spectral transmittance characteristic that blocks light in the infrared region is used, Easy-to-view images can be obtained with monochrome photography. The surface reflectance of the ND filter is preferably about 2% or less. The ND filter is preferably composed of a filter in which a metal thin film is deposited on a resin base.
[0015]
The pair of actuators can be miniaturized and have a good balance if they are fixed to the diaphragm unit substrate at a substantially symmetrical position (180 ° opposed arrangement) with the photographing aperture of the diaphragm unit substrate as the center.
[0016]
Of the pair of openings of the filter fixing plate, a light-transmitting parallel flat plate can be provided in the opening not provided with the infrared cut filter. The infrared cut filter actuator is used to position the infrared cut filter in front of the color image sensor during daylight photography, and the translucent parallel plate in front of the color image sensor during night photography. Deviation can be corrected.
[0017]
The CCTV camera diaphragm device unit preferably includes a latching machine barrel that latches the filter fixing plate when one of the pair of openings and the other of the openings are positioned on the photographing opening.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are views schematically showing the structure of a diaphragm device according to an embodiment of the present invention. 1A shows a state where an infrared cut filter (optical filter) is inserted on the optical axis (optical path), and FIG. 1B shows that the infrared cut filter is removed from the optical axis (optical path). The state is shown.
[0019]
In the CCTV camera of this embodiment, a camera body 10 and a lens barrel 18 are integrally formed. An image pickup device such as a CCD 11 is mounted on the camera body 10. Are provided with an imaging lens (not shown) and an aperture device unit (aperture device) 20. The aperture unit 20 includes an aperture 21, an infrared cut filter 22, an aperture unit substrate 23, an aperture galvanometer (aperture device actuator) 24, a filter galvanometer (infrared cut filter actuator) 25, and the like. The diaphragm galvanometer 24 is used to drive the diaphragm 21, and the filter galvanometer 25 is used to drive the infrared cut filter 22.
[0020]
In FIG. 1A, light enters the lens barrel portion 18 from the left-hand direction of the figure via an imaging lens (not shown), forms an image on the imaging surface of the CCD 11 through the diaphragm 21 and the infrared cut filter 22. Is done. At this time, the light of the infrared wavelength region is selectively cut (blocked), so that only an image with light in the visible wavelength region is formed on the imaging surface of the CCD 11. The video at this time is acquired as a color video. On the other hand, in FIG. 1B, since the infrared cut filter 22 is retracted from the optical axis L by the filter galvanometer 25, the light incident on the lens barrel portion 18 passes through the diaphragm 21 only and the CCD 11. Is imaged. That is, the CCD 11 receives light in the infrared wavelength region as well as light in the visible wavelength region. At this time, the image captured by the CCD 11 is acquired as a monochrome image. As will be described later, the aperture unit substrate 23 is provided with a circular opening sufficient to allow incident light to pass through, and the light reaches the light receiving surface of the CCD 11 through this opening.
[0021]
The diaphragm 21 is a conventionally known diaphragm composed of two diaphragm blades (see FIG. 2). That is, the diaphragm blades are made of thin metal plates having different shapes, and an aperture for the diaphragm is formed by overlapping these metal plates. The size of the opening is adjusted by shifting the arrangement of the two diaphragm blades along the unit substrate 23.
[0022]
2A and 2B show the planar shapes of the two diaphragm blades 30a and 30b, respectively. The diaphragm blades 30a and 30b are formed with substantially V-shaped notch forming portions 31a and 31b, respectively. The substantially fan-shaped members drawn by broken lines are thin and lightweight ND filters 32a and 32b based on a photographic film, and are fixed to the position shown by the broken lines with an adhesive or the like. Only one of the ND filters 32a and 32b may be bonded to the diaphragm blades 30a and 30b. In the drawing, arms 30a and 3b extending to the right are for transmitting the power of the diaphragm galvanometer 24 to the diaphragm blades, and slots 34a and 34b are formed at the distal ends of the arms 33a and 33b. The slots 34 a and 34 b are engaged with pin-like protrusions provided on the driving lever of the diaphragm galvanometer 24.
[0023]
3A and 3B show a planar shape of the filter fixing plate 40 to which the infrared cut filter 22 is attached.
[0024]
The filter fixing plate 40 is a substantially rectangular thin metal plate having an arm 43 extending in the left direction in the figure, for example, and has a long side in the longitudinal direction of the arm 43. The filter fixing plate 40 is formed with two circular openings 41 and 42 having the same size along the long side, and the circular opening 41 is covered with the infrared cut filter 22 indicated by a broken line. In the embodiment of FIG. 3 (a), the circular opening 42 is a simple through hole, and nothing is provided. The infrared cut filter 22 is fixed around the circular opening 41 of the filter fixing plate 40 by four claw portions 22a and an adhesive. A slot 44 is formed at the distal end of the arm 43 and is engaged with a pin-like protrusion provided on the drive lever of the filter galvanometer 25 as will be described later. The diameters of the circular apertures 41 and 42 are substantially equal to the diameter of the circular aperture (imaging aperture) 51 (see FIG. 4) provided in the aperture unit substrate 23 and correspond to the maximum aperture aperture (imaging aperture) in the present embodiment. To do.
[0025]
The infrared cut filter 22 has, for example, a spectral transmittance characteristic that cuts infrared light of about 700 nm or more, as indicated by a spectral transmittance characteristic curve X shown in FIG. More specifically, it has a spectral transmittance characteristic with a transmittance of about 5% or less for light in the wavelength region from the visible light region to near infrared light (about 700 nm to 1000 nm). The infrared cut filter 22 is formed as a vapor deposition interference filter made of, for example, a multilayer film.
[0026]
On the other hand, the ND filters 32a and 32b have a spectral transmittance characteristic in which the transmittance of infrared light is substantially equal to or less than the transmittance in the visible light region, as shown in the spectral transmittance characteristic Y of FIG. ing. The ND filters 32a and 32b are formed by evaporating a metal thin film made of a multilayer film on a resin base, for example. In this way, in the infrared light region, if it has a spectral transmittance characteristic almost the same as the transmittance in the visible light region, it is possible to limit the amount of transmitted light without damaging the color characteristic when performing daytime color photography. When performing monochrome photography, it is possible to limit the amount of transmitted light by sufficiently increasing the F number even in the infrared wavelength band having sensitivity.
[0027]
As the spectral transmittance characteristics of the ND filters 32a and 32b, as shown by the transmittance curve Z in FIG. When the ND filters 32a and 32b having such characteristics are positioned on the photographing optical path and monochrome photographing is performed, a portion where the reflectance of infrared light is high appears bright and does not appear to be infrared photographing. .
[0028]
The ND filters 32a and 32b preferably have a surface reflectance of about 2% or less. With such a low reflectance, there is little surface reflection of the ND filters 32a and 32b, and there is no possibility that ghost, flare, and the like are caused by light reflected on the surfaces of the ND filters 32a and 32b.
[0029]
Next, with reference to FIG. 4 to FIG. 7, the diaphragm device (throttle device unit) of the present embodiment will be described. The aperture unit substrate 23 has a flat plate portion 50, and is arranged along the surface (first surface) side of the flat plate portion 50 in a state where the aperture blades 30 a and 30 b are overlapped, and the galvanometer 24. , 25 are attached. On the other hand, the filter fixing plate 40 is disposed along the back surface (second surface) of the flat plate portion 50 of the aperture unit substrate 23. A circular opening 51 for allowing incident light to pass is formed near the substantially central portion of the flat plate portion 50 (portion through which the optical axis L of the imaging optical system passes). The galvanometers 24 and 25 are disposed at both ends of the diaphragm unit substrate 23 at substantially symmetrical positions with respect to the photographing aperture 51 (180 ° opposing arrangement).
[0030]
A thick frame portion 54 is formed around the flat plate portion 50. The frame portion 54 is provided with two projecting portions 55 for fixing the aperture unit substrate 23 to a support member (not shown) in the lens barrel. A hole 55a for passing a screw is formed in the center of the protrusion 55, and the aperture unit substrate 50 is fixed in the lens barrel by a screw inserted into the two holes 55a. Further, the diaphragm blades 30a and 30b and the filter fixing plate 40 disposed on the flat plate portion 50 can slide along the respective surfaces of the flat plate portion 55 on the front and back side frame portions of the flat plate portion 50, and A claw-like member 56 is provided to support the surface so as not to be separated from each surface. As shown in FIGS. 4A and 4B, in this embodiment, four claw-like members 56 are provided on the front surface side and three on the back surface side.
[0031]
The diaphragm galvanometer 24 is attached at a position indicated by a circular broken line on the base 52 on the right side of FIG. 4 (upper side of FIGS. 5 and 6). On the other hand, the filter galvanometer 25 is attached to a position indicated by a circular broken line on the base 53 on the left side of FIG. 4 (the lower side in FIGS. 5 and 6), and a circular broken line drawn on each of the bases 52 and 53. At the center, shaft holes 52a and 53a are provided for passing through the rotation shafts of the galvanometers 24 and 25, respectively.
[0032]
In the side view of FIG. 4C, the lower side of the drawing corresponds to the front side, and the upper side corresponds to the back side. That is, the left and right base parts 52 and 53 are provided at a position lower than the flat plate part 50 in the drawing. Recessed spaces 52b and 53b are formed substantially along the shape of each of the base parts 52 and 53 on the back side of the base parts 52 and 53, and the rotary shafts 24c and 25c of each galvanometer pass through the shaft holes 52a and 53a. The levers reach the concave sounds 52b and 53b. The drive levers 24a, 24b and 25a attached to the rotation shafts of the galvanometers are housed in the concave spaces 52b and 53b, respectively.
[0033]
An opening 52c is formed on the side surface on the flat plate portion 50 side of the base portion 52 to which the diaphragm galvanometer 24 is attached. Further, the flat plate portion 50 ends before the pedestal portion 52 and forms an end face 50a. That is, the concave space 52b communicates with the space on the front surface side of the flat plate portion 50, and the arms 33a and 33b of the diaphragm blades 30a and 30b pass through the opening 52c of the drive levers 24a and 24b accommodated in the concave space 52b. The pin-like protrusions 24d and 24e are engaged with the slots 34a and 34b, respectively. On the other hand, the arm 34 of the filter fixing plate 40 is engaged with the pin-like protrusion 25d of the drive lever 25a accommodated in the concave space 53b via the slot 44 provided at the tip thereof.
[0034]
The drive levers 24a and 24b attached to the rotary shaft 24c of the diaphragm galvanometer 24 are urged around the rotary shaft 24c (counterclockwise in FIG. 6) by the spring 57. 5 and 6 show the arrangement when the diaphragm galvanometer 24 is not driven. Only the urging force of the spring 57 acts on the drive levers 24a and 24b, and the drive levers 24a and 24b are shown in FIG. It is at the position most rotated counterclockwise (clockwise in FIG. 7). At this time, the aperture blade 30a is at the position most drawn toward the platform 52, and the aperture blade 30b is at the position farthest from the platform 52 side. That is, the two substantially V-shaped notch forming portions 31a and 31b overlap each other at a substantially central portion of the opening 51 to form a substantially square stop aperture (optical path). At this time, as shown by the broken line in FIG. 5, the substantially fan-shaped ND filters 33a and 33b are overlapped on the square aperture to attenuate the amount of light passing through the aperture. If the ND filters 33a and 33b have spectral transmittance characteristics such as Y and Z in FIG. 8, infrared light is blocked.
[0035]
When the diaphragm galvanometer 24 is driven and the drive levers 24a and 24b are rotated clockwise in FIG. 6 (counterclockwise in FIG. 5), the diaphragm blade 30a is moved away from the base 52, and the diaphragm blade is moved. 30 b is moved in the direction of the platform 52. As a result, the openings formed by the two substantially V-shaped notch forming portions 31a and 31b become larger with the rotation of the drive levers 24a and 24b, and the rotation of the drive levers 24a and 24b is maximized clockwise (in FIG. 6). When reaching this position, the circular opening 51 is completely included in the openings formed by the two substantially V-shaped notch forming portions 31a and 31b. At this time, the ND filters 33 a and 33 b are both outside the circular opening 51, and the size of the stop matches the circular opening 51. That is, the ND filters 33a and 33b are both retracted from the photographing optical path (circular opening 51).
[0036]
On the other hand, the base of a latching lever 58 is attached to the rotating shaft 25c of the filter galvanometer 25 in addition to the drive lever 25a. The latching lever 58 is made of a synthetic resin material such as Delrin (trade name). The latching lever 58 has an arc-shaped arm portion at the tip (free end) thereof, and protrudes in the radial direction of the rotary shaft 25c at the tip. A latching projection 58a is provided. The latching lever 58 has a spring property by bending the arc-shaped arm portion, and forms a latching mechanism together with the latching fixing grooves 59a and 59b formed in the concave space 53b of the base portion 53. In FIG. 6, the protrusion 58a is locked in the fixing groove 59a, and at this time, the drive lever 25a of the filter galvanometer 25 is at the end rotated counterclockwise. In other words, the filter fixing plate 40 is disposed near the base 53 and is held at a position where the center of the circular opening 42 coincides with the optical axis L. Therefore, in the arrangement shown in FIG. 6, the light enters the camera body 10 through the circular opening 42.
[0037]
Further, when the filter galvanometer 25 is driven and the driving lever 25a is rotated clockwise in FIG. 6, the protrusion 58a of the latching lever 58 is detached from the fixing groove 59a, and is thereafter locked in the fixing groove 59b. The This locking position is the clockwise rotation end of the drive lever 25a. At this time, with the rotation of the driving lever 25a, the filter fixing plate 40 is moved in the direction of the base 52, and is held at a position where the center of the circular opening 41 coincides with the optical axis L. That is, the light enters the camera body 10 through the infrared cut filter 22 provided in the circular opening 41.
[0038]
As described above, the infrared cut filter 22 is inserted into and removed from the optical path in the lens barrel 18 by rotating the filter galvanometer 25 forward and backward.
[0039]
The diaphragm galvanometer 24 and the filter galvanometer 25 are provided with two pairs of electrode terminals 61a and 61b and 62a and 62b (see FIG. 5), respectively. The electrode terminals 61a and 61b are for supplying electric power for driving the galvanometer, and the electrode terminals 61b and 62b are connected to a generator provided in the meter for detecting the rotational speed of each galvanometer, for example. Terminal. The cords 61 and 62 connected to the respective electrode terminals are guided to respective control circuits or the like (not shown).
[0040]
As described above, according to the present embodiment, the mechanism for inserting and removing the infrared cut filter on the optical path and the diaphragm mechanism using the two diaphragm blades are configured as an integral unit. The mechanism related to the filter can be made smaller, and the infrared cut filter can be stored in the lens barrel. That is, it is not necessary to separately provide a mechanism for driving the infrared cut filter in the camera body, and space can be efficiently used, so that the camera can be downsized.
[0041]
In this embodiment, a galvanometer is used as a driving actuator for the diaphragm blades and the filter fixing plate, but another driving device may be used. However, the galvanometer is suitable as a small actuator, and the device can be further miniaturized, and the durability is improved and the circuit configuration is simplified as compared with the case where the motor is used in the drive device. Thereby, the manufacturing cost is also reduced. Further, by arranging the pair of galvanometers opposite to the aperture unit substrate by 180 °, a compact and well-balanced aperture device unit can be obtained. In this embodiment, the galvanometer is provided with the generator. However, for example, the filter galvanometer may not include the generator.
[0042]
Although it is possible to attach a flat plate-like cover member that holds the filter fixing plate and the diaphragm blade to each surface of the diaphragm unit substrate, if a claw-like member is used as in this embodiment, the diaphragm device The thickness can be reduced and the cost of the member can be reduced.
[0043]
In this embodiment, an infrared cut filter is attached to the filter fixing plate, but the type of filter can be changed according to the application of the camera. Similarly, the diaphragm plate is provided with an ND filter having spectral transmittance characteristics as indicated by Y and Z in FIG. 9, but the spectral transmittance including whether or not a filter is provided on the diaphragm plate depending on the application of the camera. Characteristics can be set freely.
[0044]
However, for example, an infrared cut filter having a spectral transmittance characteristic as shown by X in FIG. 9 is provided on the filter fixing plate, and an ND filter having a spectral transmittance characteristic as shown by Y and Z in FIG. 9 is provided on the diaphragm plate. Therefore, it can be suitably used for a CCTV camera that performs color photography during the day and monochrome photography at night.
[0045]
Furthermore, the present invention does not matter the configuration of the photographing lens disposed in the lens barrel portion 18. In other words, as a photographic lens, a lens system that has been corrected for aberrations with emphasis on the visible light region is used in the past, and in the near-infrared light region (nighttime shoot), the focus position is corrected. Instead, a translucent plane plate having a different predetermined thickness has been inserted, but recently, a lens system that has been corrected to an allowable range for focusing during daytime shooting and nighttime shooting has also been proposed. . In the present invention, any type of photographing lens may be used. When a translucent parallel plate is inserted, the translucent parallel plate 22X is inserted into the opening 42 on the side of the filter fixing plate 40 that does not include the infrared cut filter 22, as shown in FIG. Can be provided. This translucent plane-parallel plate 22X has the same optical thickness (refractive index × thickness) as that of the infrared cut filter 22 when used in a lens system in which focus movement is corrected to allow for daytime shooting and nighttime shooting. A light-transmitting parallel flat plate is used. In addition, in a lens system in which aberration correction is performed with emphasis on the visible light region, a light-transmitting parallel flat plate having a thickness capable of correcting the focus position in photographing in the near infrared light region (night photographing).
[0046]
Although the CCTV camera of the present embodiment is a camera in which the camera body and the lens barrel are integrally formed, the lens barrel and the camera body may be separable.
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a small CCTV camera lens diaphragm device in which the diaphragm and the mechanism portion of the optical filter are provided in the lens barrel. Further, by arranging two diaphragm blades and a filter fixing plate for fixing the optical filter along the front and back surfaces of the diaphragm unit substrate, the diaphragm device can be made thinner and smaller. Furthermore, in an aspect in which an ND filter having a spectral transmittance characteristic in which the infrared light transmittance is substantially the same as or less than or equal to the transmittance in the visible light region is pasted on the diaphragm blade, color characteristics are obtained in color photography. It is possible to limit the amount of transmitted light without damaging it, and in monochrome photography, the total amount of light including visible light and infrared light is sufficiently suppressed, preventing the phenomenon that the subject part with strong infrared light reflection appears bright. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an embodiment of a CCTV camera diaphragm device according to the present invention.
FIG. 2 is a diagram illustrating a planar shape of two diaphragm blades of the diaphragm device.
FIG. 3 is a diagram illustrating a planar shape of a filter fixing plate to which an infrared cut filter is attached.
FIG. 4 is a front view, a back view, and a side view of an aperture unit substrate.
FIG. 5 is a diagram of a diaphragm unit substrate to which diaphragm blades and a filter fixing plate are attached as viewed from the surface side.
FIG. 6 is a view of an aperture unit substrate to which aperture blades and a filter fixing plate are attached as viewed from the back side.
FIG. 7 is a view of a diaphragm unit substrate to which diaphragm blades and a filter fixing plate are attached as viewed from the side surface side.
FIG. 8 is a graph showing an example of spectral transmittance characteristics of an infrared cut filter and an ND filter used in the aperture device of the present invention.
FIG. 9 is a diagram schematically showing the structure of a conventional CCTV camera provided with an infrared cut filter.
FIG. 10 is a graph showing spectral transmittance characteristics of a conventional general ND filter.
[Explanation of symbols]
18 Lens barrel
21 Aperture
22 Infrared cut filter
22X parallel flat plate
23 Aperture unit board
24 Galvanometer (actuator) for diaphragm
25 Galvanometer for filter (actuator)
30a 30b Aperture blade
32a 32b ND filter
40 Filter fixing plate

Claims (13)

An aperture provided in the lens barrel of the CCTV camera ;
A diaphragm unit substrate having a flat plate shape for holding the diaphragm;
Diaphragm driving means for adjusting the size of the aperture of the diaphragm;
An infrared cut filter that blocks light in the infrared region;
Filter driving means for inserting and removing the infrared cut filter on the optical path,
The diaphragm has two blades, and in the light transmitting portion that forms the diaphragm opening, the transmittance in the infrared region is approximately equal to or less than or equal to the transmittance in the visible light region. An ND filter having a spectral transmittance characteristic for blocking light is provided,
The diaphragm and the infrared cut filter are arranged along the diaphragm unit substrate,
Aperture above the stop unit plate, said diaphragm driving means, the infrared cut filter, and all of the filter drive means has been arranged in the lens barrel,
The CCTV camera adjusts the amount of light by driving the aperture driving means, and at the time of daylighting, the infrared cut filter is inserted into the optical path for color photography, and at night, the infrared cut filter is retracted from the optical path. An aperture device for a CCTV camera lens, wherein monochrome imaging is performed .   The infrared cut filter is provided in at least one opening of a flat plate-shaped filter fixing plate having two openings, and the two diaphragm blades and the filter fixing plate are first and second of the diaphragm unit substrate, respectively. The CCTV camera lens diaphragm device according to claim 1, wherein the filter driving means selectively moves the two openings of the filter fixing plate on the optical path.   The position of the infrared cut filter when the infrared cut filter is inserted on the optical path and the position of the infrared cut filter when the infrared cut filter is removed from the optical path are held. The CCTV camera lens diaphragm device according to claim 2, wherein the filter driving means includes a latching mechanism for the CCTV camera.   4. The CCTV camera lens diaphragm device according to claim 3, wherein the infrared region has a wavelength of about 700 nm to 1000 nm.   5. The aperture device for a lens for a CCTV camera according to claim 1, wherein the surface reflectance of the ND filter is about 2% or less.   6. The CCTV camera lens aperture device according to claim 1, wherein the ND filter is a filter in which a metal thin film is deposited on a resin base. A diaphragm unit provided in a lens barrel of a CCTV camera equipped with a color image sensor,
A diaphragm unit substrate having a flat plate portion having a photographing aperture;
A pair of openings corresponding to the photographing openings is provided, and an infrared cut filter for blocking light in an infrared region is provided in one of the openings, and one of the front and back sides of the flat plate portion of the unit substrate is provided. A filter fixing plate supported movably on the surface;
Two diaphragm plates that are movably supported on the other surface of the flat plate portion and change the size of the diaphragm aperture that overlaps the imaging aperture according to the relative movement position;
Spectral transmittance characteristics that are attached to at least one of the two diaphragm plates so as to be positioned on the aperture opening and whose transmittance in the infrared region is substantially equal to or less than the transmittance in the visible light region, or An ND filter having a spectral transmittance characteristic that blocks light in the infrared region;
To the stop unit substrate was supported by sandwiching the flat plate portion, and an actuator for an infrared cut filter is positioned on the photographing opening by chosing the pair of openings by reciprocating the filter fixing plate, the A pair of actuators comprising a diaphragm driving actuator that relatively moves two diaphragm plates in opposite directions to change the diaphragm aperture ;
The diaphragm driving actuator is driven to adjust the amount of light, and at the time of daylight photographing, the infrared cut filter actuator is driven to position the opening on which the infrared cut filter is attached to the photographing opening for color photographing, throttling device unit CCTV camera lens at the time of night photography, wherein take a picture monochrome drives the actuator for the infrared cut filter is positioned in the photographic opening the other of the pair of openings.   8. The aperture device unit for a CCTV camera lens according to claim 7, wherein the pair of actuators are fixed to the diaphragm unit substrate at a substantially symmetrical position about the photographing aperture of the diaphragm unit substrate.   Of the pair of openings of the filter fixing plate, the opening on the side not provided with the infrared cut filter is provided with a translucent parallel flat plate, and the infrared cut filter actuator is configured to transmit the infrared light during daylight photography. The aperture device unit for a CCTV camera lens according to claim 7 or 8, wherein the cut filter is positioned in front of the color image sensor and the translucent plane-parallel plate is positioned in front of the color image sensor during night photography.   The CCTV camera lens diaphragm device according to any one of claims 7 to 9, further comprising a latching mechanism that latches the filter fixing plate when one of the pair of openings and the other of the openings are positioned on the photographing opening. unit.   The CCTV camera lens diaphragm device unit according to any one of claims 7 to 10, wherein the infrared region has a wavelength of about 700 nm to 1000 nm.   The aperture device unit for a CCTV camera lens according to any one of claims 7 to 11, wherein the surface reflectance of the ND filter is about 2% or less.   The said ND filter is a diaphragm apparatus unit of the lens for CCTV cameras of any one of Claim 7 thru | or 12 which is a filter which vapor-deposited the metal thin film on the resin base.

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