JP2005250227A - Imaging lens, imaging unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the fluctuation of optical characteristics due to the insertion/detachment of an infrared cut filter into/from an optical path. <P>SOLUTION: Regarding the imaging lens 2 capable of selectively performing photographing with low-illuminance and normal photographing by inserting/detaching the infrared cut filter 5 into/from the optical path, the infrared cut filter is formed by applying a vapor-deposited film having an effect of cutting infrared rays on an organic substance substrate, and the organic substance substrate and the vapor-deposited film satisfy a conditional inequality (1) d×(n-1)<0.15, provided that (d) denotes the thickness of the infrared cut filter and (n) denotes a refractive index in the (d) line of the organic substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel imaging lens, imaging unit, and imaging apparatus. Specifically, low-illuminance photography and normal photography can be selectively performed by putting an infrared cut filter in and out of the optical path, and optical characteristics change due to the infrared cut filter being taken in and out of the optical path is reduced. Related to technology.

  When an imaging device such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor) is used in an imaging device such as a video camera, a digital still camera, a small module camera, or a surveillance camera, It was necessary to insert a filter that cuts infrared rays into the optical path during normal photographing.

  Further, in an imaging apparatus using the imaging device as described above, by taking out the infrared cut filter inserted in the optical path from the optical path by utilizing the fact that the imaging device has high sensitivity to infrared rays. Some have made it possible to shoot under low illumination. For example, Patent Document 1 proposes a video camera capable of low-illuminance shooting.

  The lens barrel of the video camera shown in Patent Document 1 has a switching mechanism for moving the infrared filter (cut) between the optical path and a position off the optical path, and operates the switching mechanism. Thus, low-illuminance shooting and normal shooting can be selectively performed.

JP 11-125852 A

  By the way, conventionally, an infrared cut filter is usually configured by forming a thin film having an infrared ray removing function on a glass substrate. In the era when the conventional size and weight are not much concerned, it was not a problem to use glass as the base material of the infrared cut filter, but there is a great demand for miniaturization and weight reduction. The weight and size (particularly thickness) cannot be ignored when glass is used as the filter substrate. Therefore, when an infrared cut filter using a glass substrate is used, a space for holding only a thick infrared cut filter is required for the switching mechanism, which affects the layout of the entire lens barrel, and is downsized. It was an adverse effect of weight reduction.

  In addition, since the infrared cut filter itself has a slight refractive index, when the refractive index of the filter is n and the thickness is t, the imaging position is Δd = t (n−1) / n. It is necessary to correct the image formation position with the focus lens, and a mechanical margin is required for this purpose. This is an adverse effect not only on the lens barrel design but also on the optical design. Furthermore, in terms of optical performance, the field curvature is inevitably deteriorated. Furthermore, when the infrared cut filter is manufactured by depositing a thin film on a base material, it has an angle dependency with respect to the incident light, so that the influence on the optical performance such as deterioration of peripheral chromatic aberration has been increased.

  Therefore, an object of the present invention is to reduce fluctuations in optical characteristics due to insertion and removal of the infrared cut filter into and from the optical path.

  In order to solve the above-described problems, the imaging lens of the present invention is an imaging lens that can selectively perform low-illuminance shooting and normal shooting by putting the infrared cut filter into and out of the optical path. The organic material substrate is formed by providing a vapor deposition film having an effect of cutting infrared rays on the organic material substrate, wherein d is the thickness of the infrared cut filter, and n is the d line of the organic material substrate. As the refractive index, the conditional expression (1) d × (n−1) <0.15 is satisfied.

  Further, in order to solve the above-described problem, the imaging unit of the present invention includes an imaging lens capable of selectively performing low-illuminance shooting and normal shooting by putting an infrared cut filter into and out of the optical path, and the imaging lens. An imaging unit including an imaging unit that captures an optical image formed by the infrared cut filter, wherein the infrared cut filter is formed by providing a vapor deposition film having an effect of cutting infrared rays on an organic material substrate, The organic material substrate and the vapor deposition film satisfy the conditional expression (1) d × (n−1) <0.15, where d is the thickness of the infrared cut filter and n is the refractive index at the d line of the organic material substrate. Is.

  Furthermore, in order to solve the above-described problems, the imaging apparatus of the present invention includes an imaging lens capable of selectively performing low-illuminance shooting and normal shooting by putting an infrared cut filter into and out of the optical path, and the imaging lens. An image pickup apparatus including an image pickup unit that picks up an optical image formed by the image pickup unit and a recording unit that records an image picked up by the image pickup unit, wherein the infrared cut filter has an effect of cutting infrared rays. The vapor deposition film is formed on the organic material substrate, and the organic material substrate and the vapor deposition film are defined by conditional expression (1) where d is the thickness of the infrared cut filter and n is the refractive index at the d line of the organic material substrate. d × (n−1) <0.15 is satisfied.

  Therefore, in the present invention, it is possible to suppress fluctuations in the imaging position when switching between normal shooting and low illumination shooting, and it is possible to reduce the size and weight.

  The imaging lens of the present invention is an imaging lens capable of selectively performing low-lighting photography and normal photography by inserting and removing the infrared cut filter in the optical path, and the infrared cut filter has an effect of cutting infrared rays. The vapor deposition film is formed on the organic material substrate, and the organic material substrate and the vapor deposition film are defined by conditional expression (1) where d is the thickness of the infrared cut filter and n is the refractive index at the d line of the organic material substrate. d × (n−1) <0.15 is satisfied.

  In addition, the imaging unit of the present invention captures an optical lens formed by the imaging lens capable of selectively performing low-illuminance shooting and normal shooting by inserting and removing the infrared cut filter into and from the optical path. An imaging unit including an imaging unit, wherein the infrared cut filter is formed by applying a vapor deposition film having an effect of cutting infrared rays to an organic material substrate, and the organic material substrate and the vapor deposition film are d Is the thickness of the infrared cut filter, and n is the refractive index at the d-line of the organic material substrate, the conditional expression (1) d × (n−1) <0.15 is satisfied.

  Furthermore, in order to solve the above-described problems, the imaging apparatus of the present invention includes an imaging lens capable of selectively performing low-illuminance shooting and normal shooting by putting an infrared cut filter into and out of the optical path, and the imaging lens. An image pickup apparatus including an image pickup unit that picks up an optical image formed by the image pickup unit and a recording unit that records an image picked up by the image pickup unit, wherein the infrared cut filter has an effect of cutting infrared rays. The vapor deposition film is formed on the organic material substrate, and the organic material substrate and the vapor deposition film are defined by conditional expression (1) where d is the thickness of the infrared cut filter and n is the refractive index at the d line of the organic material substrate. d × (n−1) <0.15 is satisfied.

  Therefore, in the present invention, the infrared cut filter can be formed thin and lightweight. For this reason, the influence of the thickness of the infrared cut filter can be minimized, and the driving force of the mechanism for moving the infrared cut filter can be reduced, so that the imaging position when switching between normal shooting and low illumination shooting can be reduced. The variation can be suppressed, the curvature of field can be suppressed, and further, the size and weight can be reduced.

  In the invention described in claim 2, claim 18 and claim 34, r1 is the radius of curvature of the image side surface of the infrared cut filter, r2 is the radius of curvature of the object side surface of the infrared cut filter, and EXP is Conditional expression (2) 0.9 <| r1 / r2 | <1.1 and condition, where D is the distance between the exit pupil and the image plane, and D is the distance between the infrared cut filter and the image plane on the optical axis. Since the infrared cut filter is curved so as to satisfy the formula (3) 0.8 <| r1 / r2 | / (EXP-D) <1.2, it is incident on the deposited film of the infrared cut filter. The incident angle of the incident light can be made shallower, whereby the incident angle dependence of the spectral characteristic of the infrared cut filter can be minimized. Therefore, variation in chromatic aberration due to switching between normal shooting and low illumination shooting can be suppressed. Furthermore, even when the light reflected by the imaging surface is further reflected by the image side surface of the infrared cut filter, the light reflected by the image side surface of the infrared cut filter does not enter the imaging surface again. Therefore, it is possible to prevent a so-called ghost from being generated by inserting the infrared cut filter on the optical path.

  In the invention described in claim 3, claim 4, claim 19, claim 20, claim 35, and claim 36, the infrared cut filter has at least one layer on each side of the organic material substrate. Since the vapor deposition film is provided, the infrared cut filter can have a desired curvature by balancing the stress generated in the vapor deposition films on both sides in a desired state. Further, deformation due to temperature can be minimized.

  In the inventions described in claims 5 to 8, 21 to 24, and 37 to 40, the infrared cut filter also has a function of a light amount adjustment filter. It is no longer necessary to provide a separate filter, and the cost can be reduced and the size and weight can be reduced by reducing the number of parts.

  In the invention described in claims 9 to 16, 25 to 32, and 41 to 48, since the ultraviolet cut film is deposited on the infrared cut filter, it is possible to perform normal photographing. The amount of infrared rays and ultraviolet rays that reach the imaging surface is adjusted during low-illuminance shooting, and an ideal light beam under each shooting condition can reach the imaging surface. In addition, when a solid-state image sensor such as a CCD or CMOS is used, deterioration of the solid-state image sensor due to ultraviolet rays can be suppressed.

  The best mode for carrying out the imaging lens, imaging unit, and imaging apparatus of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram showing a first embodiment of an imaging unit.

  The imaging unit 1 includes an imaging lens 2 and an imaging unit 3 that captures an optical image formed by the imaging lens 2. As the image pickup means 3, an image pickup element such as a CCD or CMOS is generally used, but this does not mean that the image pickup means in the present invention is limited to an image pickup element such as a CCD or CMOS.

  The imaging lens 2 includes a lens system 4 configured by a plurality of lenses L, L,... And an infrared cut filter 5 configured to be detachable on the optical path of the lens system 4. As the lens system 4, an appropriate type of lens system such as a single focus lens system, a zoom lens system, and a variable focus lens system can be applied. The lenses L, L,... Constituting the lens system 4 are not limited to refractive lenses, but may be appropriate types of lenses such as diffractive lenses and hybrid lenses.

  The infrared cut filter 5 is formed by depositing a film having an effect of cutting infrared rays on an organic material substrate. The organic substance that becomes the substrate of the infrared cut filter 5 is not particularly limited, and the vapor deposition film only needs to have an effect of cutting infrared rays.

  In the image pickup unit 1 shown in FIG. 1, the infrared cut filter 5 is inserted on the optical path of the lens system 4 as shown by a solid line during normal shooting, and the light beam l emitted from the object O is reflected by the subject 6. Then, it passes through the lens system 4 and the infrared cut filter 5 and reaches the image pickup means 3. Then, when passing through the infrared cut filter 5, the infrared ray is cut from the luminous flux l by the vapor deposition film. Further, at the time of low-illuminance shooting, the infrared cut filter 5 is removed from the optical path of the lens system 4 as indicated by a broken line. Therefore, the red means optimal for being recognized as an image at low illuminance by the imaging means 3. Outer rays arrive.

In the infrared cut filter 5, the thickness of the infrared cut filter 5 is d, and the refractive index at the d line of the organic material substrate constituting the infrared cut filter 5 is n.
(1) d × (n−1) <0.15
It is necessary to satisfy the following conditional expression.

  Conditional expression (1) determines the conditions necessary to achieve miniaturization and weight reduction while suppressing fluctuations in the imaging position due to switching between normal photographing and low illumination photographing. If this condition is not met, fluctuations in the imaging position due to switching between normal shooting and low-illuminance shooting will increase, and an adjustment means for this will be required, and the moving mechanism of the infrared cut filter 5 will become larger, thereby taking an image. The lens 1 is prevented from being reduced in size and weight. If the above condition is not met, the field curvature at the wide end will vary significantly due to switching between normal shooting and low illumination shooting.

  FIG. 2 is a conceptual diagram showing a second embodiment of the imaging unit. In the imaging unit 1A according to the second embodiment, the infrared rays are cut so that the incident angle θ of the luminous flux 7 becomes shallower with respect to the luminous flux 7 incident on the infrared cutoff filter 5A with the maximum incident angle. The filter 5A is curved. In FIG. 2, the lens system 4 is simply shown.

  Specifically, the distance between the exit pupil of the lens and the image plane is EXP, the radius of curvature of the image side surface of the infrared cut filter is r1, the radius of curvature of the object side surface of the infrared cut filter is r2, the optical axis The following conditional expressions (2) and (3) are satisfied, where D is the distance between the infrared cut filter and the image plane.

(2) 0.9 <| r1 / r2 | <1.1
(3) 0.8 <| r1 / r2 | / (EXP-D) <1.2
That is, the infrared cut filter 5A satisfies the conditional expressions (2) and (3), and has a cylindrical shape in a direction in which the incident angle of each light beam from the axial light beam to the peripheral light beam becomes shallow (closes to 0). It is curved with a curved surface such as a spherical surface or a free-form surface. This makes it possible to reduce the incident angle of the luminous flux with respect to the vapor deposition film, and to minimize the incident angle dependency of the spectral characteristics of the infrared cut filter 5A. And if it remove | deviates from the conditions of conditional expression (2), the infrared cut filter 5A itself has power (having a lens function), and it becomes difficult to form a desired curved surface. If the condition of the conditional expression (3) is not satisfied, the characteristics of the light beam reaching the image pickup means 3 vary significantly depending on the image height due to the incident angle dependency of the spectral characteristics, making it difficult to satisfy the required characteristics. Become.

  FIG. 3 shows an effect of preventing the light beam reflected by the imaging means 3 from becoming ghost light in the imaging unit 1A according to the second embodiment shown in FIG. When the infrared cut filter 5 is flat (see FIG. 3A), the light beam la reflected by the imaging unit 3 is reflected by the infrared cut filter 5, and the light lg is incident on the image pickup unit 3 again. The light lg becomes ghost light. However, in the imaging unit 1A, the image-side surface of the infrared cut filter 5A is convexly curved toward the image side, and as shown in FIG. The light la reflected by the image pickup means 3 and directed to the infrared cut filter 5A is reflected to the outside of the image pickup means 3 by the infrared cut filter 5A (see the light ray ng) and does not become ghost light.

  FIG. 4 shows a third embodiment of an infrared cut filter according to the present invention. In the infrared cut filter 5B according to this embodiment, vapor deposited films 9 and 10 each having one or more layers are formed on both surfaces of the organic material substrate 8. The vapor deposition films 9 and 10 are subjected to a force to bend as shown by the broken line due to the stress generated inside. Therefore, the infrared cut filter 5B can have a desired curvature by balancing the force to be bent on the object side surface and the image side surface. That is, if the force to bend of the vapor deposition film 9 formed on the object side surface is made stronger than the force to bend of the vapor deposition film 9 formed on the image side object side surface, the curvature of the concave on the object side is increased. If the difference between the two forces is increased, the curve can be deepened. Conversely, if the difference between the two forces is decreased, the curve can be decreased. Further, by forming the vapor deposition films 9 and 10 on both surfaces of the substrate 9 and balancing the stresses generated in both the vapor deposition films 9 and 10 at a desired ratio, deformation due to temperature can be minimized.

  5 and 6 show a fourth embodiment of an infrared cut filter according to the present invention. The infrared cut filter 5C according to this embodiment is characterized by having both an infrared cut function and a light amount adjustment function.

  As can be seen from FIG. 5, in the infrared cut filter 5C, the infrared cut film 12 is deposited on one surface of the organic material substrate 11, and the light amount adjustment film 13 is deposited on the other surface of the substrate 11 (FIG. 5A). )reference). In the illustrated case, the light amount adjustment film 13 is formed with two layers 13a and 13b, and the whole is a portion 14a where the light amount adjustment film 13 is not present, a portion 14b where the one light amount adjustment film 13a is present, and a light amount adjustment. The film is divided into three parts 14c where the two layers 13a and 13b overlap (see FIG. 5B). Here, the first layer and the second layer do not indicate the actual number of times of vapor deposition but are expressions on the light amount adjustment function. In actual formation of the light amount adjustment film, the light amount adjustment films 13a and 13b may be formed by vapor deposition of several to several tens of layers, respectively.

  The infrared cut filter 5C is moved in four stages. That is, a state where a portion 14a where neither the light amount adjustment films 13a and 13b exist is located on the optical path, a state where a portion 14b where only the light amount adjustment film 13a is located is located on the optical path, or a portion 14c where both the light amount adjustment films 13a and 13b are present. It is moved in four stages: the state positioned on the optical path and the state where the entire infrared cut filter 5c is detached from the optical path. Then, the infrared cut filter 5C is removed from the optical path at the time of low illumination shooting, the portion 14c is transmitted like the light beam lh at the time of high illumination shooting, and the portion 14b or 14a is used for the light beam lm1 or lm2 at the time of shooting at intermediate illumination. Permeate (see FIG. 6). As a result, it is possible to perform optimum photographing for each light beam state, and it is not necessary to separately provide a light amount adjusting filter in addition to the infrared cut filter, and the cost is reduced by reducing the number of parts, and the size and weight are reduced. Is possible.

  FIG. 7 shows a fifth embodiment of the imaging unit of the present invention. In this embodiment, the infrared cut filter 5D is characterized by having an ultraviolet cut function.

  The infrared cut filter 5D is formed by depositing an infrared cut film 16 on one surface of an organic material substrate 15 and depositing an ultraviolet cut film 17 on the other surface. Therefore, at the time of normal photographing performed with the infrared cut filter 5D inserted in the optical path, the transmittance of infrared rays and ultraviolet rays is controlled, and an ideal light beam reaches the imaging means. In addition, when a solid-state image sensor such as a CCD or CMOS is used, deterioration of the solid-state image sensor due to ultraviolet rays can be suppressed.

  Using polyolefin known as ZEONR (product name of Nippon Kayaku Co., Ltd.) as a substrate, 45 layers of ultrathin titanium and silica layers (both sides) so that both sides of the substrate are approximately the same thickness And an infrared cut filter having a total thickness of 50 μm.

  FIG. 8 shows the result of a daylight transmission test performed on the infrared cut filter in a 25 ° C. environment. As can be seen in FIG. 8, the infrared rays are cut very well.

  The infrared cut filter has a wavelength of 50% on the long wavelength side of visible light at a temperature of 25 ° C., λL, an amount of change in environmental temperature of ΔT, and a wavelength of 50% on the long wavelength side of visible light after the environmental temperature changes. When the value is λC, the condition of (| λC−λL |) /ΔT≦0.07 is satisfied, and this is transmitted in daylight in an environment of 25 ° C., −30 ° C. and 45 ° C. The result of the test is shown in FIG. As can be seen from FIG. 9, it is clear that the variation of the infrared ray cut rate with respect to the temperature change is extremely small, and it functions sufficiently in a wide temperature environment. If the above condition is not satisfied, the color of the image changes due to a temperature change, the color difference from the subject increases, and it is difficult to obtain good image quality.

  10 and 11 show an embodiment of the imaging apparatus of the present invention. In the illustrated embodiment, the imaging apparatus of the present invention is applied to a video camera.

  Referring to FIG. 10, a part of the imaging lens 22 protrudes from the front end of the outer casing 21 of the video camera 20, and an EVF (electric viewfinder) is provided on the upper surface of the outer casing 21 so that the angle can be changed. A tape cassette mounting portion 23 is provided on the side surface of the outer casing 21 so that a tape cassette (not shown) can be attached and detached. Further, a changeover switch 24 is provided at a position near the front end of the side surface of the outer casing 21, and normal shooting and low-illuminance shooting can be switched by operating the changeover switch 24. Further, an infrared light 25 is disposed on the front surface of the outer casing 21. In addition to the above-described ones, a recording switch, various setting switches, a battery mounting unit, and the like are provided on the outer surface of the outer casing 21, but illustration and description thereof are omitted.

  As can be seen from FIG. 11, in the outer casing 21, an infrared cut filter 21c constituting the imaging lens 21 together with a lens system 21b supported by the lens barrel 21a is provided with imaging means (here, a CCD having sensitivity to infrared rays). 26) and the lens system 21b are arranged so as to be able to be put in and out of the optical path. The infrared cut filter 21c is supported by a holding frame 27 that is movably provided. The infrared cut filter 21c is inserted into the optical path of the imaging lens 21 by moving the holding frame 27 by operating the changeover switch 24. (See FIG. 11 (b)) or detached from the optical path of the imaging lens 21 (see FIG. 11 (a)). The infrared light 25 is connected to the battery 28 via a protection circuit 29, and the changeover switch 24 also switches the power supply to the infrared light 25.

  Therefore, for example, when shooting at low illuminance such as shooting at night, the changeover switch 24 is operated, and the infrared cut filter 21c is detached from the optical path of the shooting lens 21 as shown in FIG. Light 25 is turned on. As a result, the infrared rays of the infrared light 25 reflected from the subject are controlled by the lens system 21b and directly reach the image pickup means (CCD) 26, and an image of infrared rays is formed in the image pickup means 26. Further, during normal shooting such as shooting in daylight, the selector switch 24 is operated to insert the infrared cut filter 21c into the optical path of the imaging lens 21 and energize the infrared light 25 as shown in FIG. Shut off. As a result, daylight reflected by the subject reaches the imaging means 26 via the lens system 21b and the infrared cut filter 21c. Accordingly, since the infrared rays are not included in the light reaching the image pickup means 26, even if the image pickup means 26 has sensitivity to the infrared rays, no image of infrared rays is formed in the image pickup means 26. The image formed on the image pickup means 26 is recorded on the tape of the tape cassette or another recording means in both low-illuminance shooting and normal shooting.

  In the above embodiment, a video camera is shown as the imaging device. However, the imaging device in the present invention is not limited to the video camera. For example, the present invention can be implemented in various forms such as a digital still camera, a PDA (Personal Digital Assistance), a camera built in a portable device such as a cellular phone, and the like, and these are also included in the technical scope of the present invention. .

  In addition, the shape and structure of each part shown in each of the above-described embodiments are merely examples of implementations in carrying out the present invention, and the technical scope of the present invention is limited by these. It should not be interpreted in a general way.

  It is suitable for application to an imaging apparatus that selectively performs shooting under low illuminance such as at night and normal shooting such as shooting under daylight.

It is a schematic block diagram which shows 1st Embodiment of this invention imaging unit. FIG. 3 shows a second embodiment of the image pickup unit together with FIG. 3, and is a schematic configuration diagram. It is the schematic explaining the effect | action which prevents ghost light, (a) shows the mechanism of ghost light generation | occurrence | production, (b) shows the mechanism by which generation | occurrence | production of ghost light is prevented by this Embodiment. It is. It is the schematic which shows 3rd Embodiment of the infrared cut filter in this invention. FIG. 6 shows a fourth embodiment of an infrared cut filter according to the present invention together with FIG. 6, which shows the configuration of the infrared cut filter, (a) is a rear view, and (b) is a sectional view. . It is the schematic which shows an effect | action. It is a schematic block diagram which shows 5th Embodiment of an imaging unit. It is a graph which shows the transmission characteristic of the infrared cut filter by an Example. It is a graph which shows the temperature characteristic of the infrared cut filter by an Example. FIG. 11 shows an embodiment of the imaging apparatus of the present invention together with FIG. 11, and this figure is a perspective view showing an appearance. It is a schematic perspective view which shows operation | movement, (a) shows the state at the time of low illumination imaging | photography, (b) shows the state at the time of normal imaging | photography.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging unit, 2 ... Imaging lens, 3 ... Imaging means, 4 ... Lens system, 5 ... Infrared cut filter, 1A ... Imaging unit, 2A ... Imaging lens, 5A ... Infrared cut filter, 5B ... Infrared cut filter, 8 ... Organic substance substrate, 9 ... deposited film, 10 ... deposited film, 5C ... infrared cut filter, 11 ... organic substance substrate, 12 ... infrared cut film (deposited film), 1D ... imaging unit, 2D ... imaging lens, 5D ... infrared cut Filters, 15 ... Organic material substrate, 16 ... Infrared cut film (deposition film), 17 ... UV cut film, 20 ... Video camera (imaging device), 21 ... Imaging lens, 21b ... Lens system, 21c ... Infrared cut filter, 26 ... Imaging means

Claims (48)

In an imaging lens that can selectively perform low-light shooting and normal shooting by putting an infrared cut filter in and out of the optical path,
The infrared cut filter is formed by applying a vapor deposition film having an effect of cutting infrared rays to an organic material substrate,
The imaging lens, wherein the organic material substrate and the vapor deposition film satisfy the following conditional expression (1).
(1) d × (n−1) <0.15
However,
d: Thickness of the infrared cut filter n: Refractive index at d line of the organic material substrate. The imaging lens according to claim 1, wherein the infrared cut filter is curved so as to satisfy the following conditional expressions (2) and (3).
(2) 0.9 <| r1 / r2 | <1.1
(3) 0.8 <| r1 / r2 | / (EXP-D) <1.2
However,
r1: radius of curvature of image side surface of infrared cut filter r2: radius of curvature of object side surface of infrared cut filter EXP: distance between exit pupil and image plane D: infrared cut filter and image plane on optical axis The distance between The imaging lens according to claim 1, wherein the infrared cut filter is provided with one or more deposited films on both surfaces of the organic material substrate. The imaging lens according to claim 2, wherein the infrared cut filter is provided with one or more deposited films on both surfaces of the organic material substrate. The imaging lens according to claim 1, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging lens according to claim 2, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging lens according to claim 3, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging lens according to claim 4, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging lens according to claim 1, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 2, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 3, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 4, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 5, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 6, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 7, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging lens according to claim 8, wherein an ultraviolet cut film is deposited on the infrared cut filter. An imaging unit comprising an imaging lens capable of selectively performing low-illuminance photography and normal photography by inserting and removing an infrared cut filter in the optical path, and an imaging means for imaging an optical image formed by the imaging lens Because
The infrared cut filter is formed by applying a vapor deposition film having an effect of cutting infrared rays to an organic material substrate,
The organic substance substrate and the vapor deposition film satisfy the following conditional expression (1).
(1) d × (n−1) <0.15
However,
d: Thickness of the infrared cut filter n: Refractive index at d line of the organic material substrate. The imaging unit according to claim 17, wherein the infrared cut filter is curved so as to satisfy the following conditional expressions (2) and (3).
(2) 0.9 <| r1 / r2 | <1.1
(3) 0.8 <| r1 / r2 | / (EXP-D) <1.2
However,
r1: radius of curvature of image side surface of infrared cut filter r2: radius of curvature of object side surface of infrared cut filter EXP: distance between exit pupil and image plane D: infrared cut filter and image plane on optical axis The distance between The imaging unit according to claim 17, wherein the infrared cut filter is formed by providing one or more deposited films on both surfaces of the organic material substrate. 19. The imaging unit according to claim 18, wherein the infrared cut filter is provided with one or more deposited films on both surfaces of the organic material substrate. The imaging unit according to claim 17, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging unit according to claim 18, wherein the infrared cut filter has a function of a light amount adjustment filter. The imaging unit according to claim 19, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging unit according to claim 20, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging unit according to claim 17, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 18, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 19, wherein an ultraviolet cut film is deposited on the infrared cut filter. 21. The imaging unit according to claim 20, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 21, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 22, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 23, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging unit according to claim 24, wherein an ultraviolet cut film is deposited on the infrared cut filter. An imaging lens capable of selectively performing low-illuminance shooting and normal shooting by inserting / removing an infrared cut filter into / from the optical path, an imaging unit for imaging an optical image formed by the imaging lens, and the imaging unit An image pickup apparatus comprising a recording means for recording a picked-up image,
The infrared cut filter is formed by applying a vapor deposition film having an effect of cutting infrared rays to an organic material substrate,
The imaging apparatus, wherein the organic material substrate and the vapor deposition film satisfy the following conditional expression (1).
(1) d × (n−1) <0.15
However,
d: Thickness of the infrared cut filter n: Refractive index at d line of the organic material substrate. The imaging device according to claim 33, wherein the infrared cut filter is curved so as to satisfy the following conditional expressions (2) and (3).
(2) 0.9 <| r1 / r2 | <1.1
(3) 0.8 <| r1 / r2 | / (EXP-D) <1.2
However,
r1: radius of curvature of image side surface of infrared cut filter r2: radius of curvature of object side surface of infrared cut filter EXP: distance between exit pupil and image plane D: infrared cut filter and image plane on optical axis The distance between 34. The imaging apparatus according to claim 33, wherein the infrared cut filter is provided with one or more deposited films on both surfaces of the organic material substrate. The imaging device according to claim 34, wherein the infrared cut filter is provided with one or more deposited films on both surfaces of the organic material substrate. The imaging device according to claim 33, wherein the infrared cut filter has a function of a light amount adjustment filter. The imaging device according to claim 34, wherein the infrared cut filter has a function of a light amount adjustment filter. 36. The imaging apparatus according to claim 35, wherein the infrared cut filter also has a function of a light amount adjustment filter. The imaging apparatus according to claim 36, wherein the infrared cut filter has a function of a light amount adjustment filter. The imaging device according to claim 33, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging device according to claim 34, wherein an ultraviolet cut film is deposited on the infrared cut filter. 36. The imaging device according to claim 35, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging device according to claim 36, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging device according to claim 37, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging device according to claim 38, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging apparatus according to claim 39, wherein an ultraviolet cut film is deposited on the infrared cut filter. The imaging device according to claim 40, wherein an ultraviolet cut film is deposited on the infrared cut filter.

Images