JP2007101709A - Nd filter, method for manufacturing nd filter, and light quantity attenuation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ND (Neutral Density) filter with which the occurrence of warpages, cracks etc. of a substrate is suppressed, and to provide a method for manufacturing the ND filter and a light quantity attenuation device. <P>SOLUTION: The ND filter 11 adjusts transmitted light quantity and is constructed by comprising a lamination film, equipped on the substrate made of a resin and ribs 13 continuously or discontinuously formed on the substrate. The rib 13 is constructed with a protrusion formed on one surface of the substrate, and a recession formed on the other surface of the substrate corresponding to the protrusion, also is constructed with a protrusion formed with application or printing on the substrate, or is constructed with a protrusion formed by bending an edge portion of the ND filter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ND filter, a method for manufacturing an ND filter, and a light amount diaphragm device, and more particularly to an ND filter used in a photographing apparatus such as a camera or an optical apparatus and a diaphragm device using the ND filter.

Conventionally, an optical device such as a digital camera or a video camera has a diaphragm device for adjusting the amount of light.
And in this diaphragm | throttle device, usually light quantity adjustment is performed using a diaphragm blade.
However, particularly for a high-luminance subject, if the aperture diameter becomes too small, the resolution is degraded due to diffraction.
Therefore, the aperture diameter is limited, and at the same time, the amount of passing light is limited by using a neutral density filter (hereinafter abbreviated as ND filter) as a light amount adjusting member, thereby preventing the image quality from deteriorating.

Specifically, an ND filter, which is a separate member from the diaphragm blades, is attached to a part of the diaphragm blades with an adhesive so that when the subject has high brightness, the diaphragm diameter is not narrowed down until it becomes too small. The aperture opening is kept constant. Instead, the ND filter is positioned on the optical axis to limit the amount of light passing through. Furthermore, as this ND filter, a filter having a gradient (hereinafter referred to as a density gradient) in its light amount adjustment function is used, and further light amount adjustment is performed by moving this filter on the optical axis. There is also.
There have also been proposed various diaphragm devices that do not have ND filters attached to the diaphragm blades and have an optical function independently.

As an ND filter as a light amount adjusting member in the light amount adjusting device as described above, a filter having a multilayer film formed by vacuum deposition or the like is generally used. For example, as disclosed in Patent Document 1, a metal film or a dielectric film formed on a transparent resin film such as PET (polyethylene terephthalate) by multilayer deposition by vacuum deposition or the like is used.
Moreover, it is reduced in weight by using resin instead of glass as a base material, is hard to break, and is reduced in cost.
In addition, as a film forming method, for example, as disclosed in Patent Documents 2 and 3, it is possible to mix and knead a dye or pigment that absorbs light into a photographic printing or resin film, In this case, a light absorbing multilayer film is formed to prevent reflection on the substrate surface.
Patent Document 4 proposes an ND filter that defines the direction of the ND filter and the stretching direction of the resin film in order to reduce the influence of thermal shrinkage when producing the ND filter by a vapor deposition method.
JP-A-10-133254 JP-A-5-173004 Japanese Patent Laid-Open No. 10-96971 JP 2005-017986 A

By the way, when the ND filter is formed using the vapor deposition method as described above, the substrate is warped after being deposited at a high substrate temperature, and the substrate having such a warp is used. When used as a light amount adjusting member, it causes image deterioration. That is, when a multilayer film is formed on a resin substrate (substrate) by vapor deposition, the substrate is heated by a halogen heater or the like installed in the vapor deposition apparatus in order to improve the adhesion between the substrate and the multilayer film. .
Furthermore, the substrate temperature rises due to the heat of the vapor deposition material deposited on the substrate and the radiant heat from the vapor deposition source that heats the vapor deposition material.
Thus, after forming into a film in the state with high substrate temperature, it takes out from a vapor deposition apparatus and cools.
Although the substrate shrinks due to this cooling, the multilayer film made of metal or dielectric has a difference in thermal expansion coefficient with respect to the resin substrate, so that the shrinkage amount differs and the substrate warps.
This warpage of the substrate remains even after being cut into a size for use as a light amount adjusting member.
When the ND filter obtained in this way is bonded to the diaphragm blades and used as a light quantity adjusting member, the amount of warpage is large, particularly when the diaphragm aperture is large, causing image deterioration.

In addition, a resin substrate having a very thin thickness of about 100 μm is used in order to reduce dispersion of transmitted light.
For this reason, it is easy to bend and the workability | operativity at the time of subsequent processes, such as cutting and adhesion | attachment, is bad, and a crack is generated in a vapor deposition film by repeating bending.
Furthermore, in recent years, as the sensitivity of the image sensor increases, the density of the ND filter tends to increase to further reduce the light transmittance.
In order to increase the concentration, it is necessary to increase the thickness of the deposited film, which causes a further increase in the substrate temperature.
As described above, since the amount of expansion and contraction due to heat of the substrate is further increased, the amount of warpage of the substrate is further increased, and further, cracks and wrinkles are generated in the deposited film immediately after deposition.
In addition, in the thing of above-mentioned patent document 4, the direction of an ND filter and the extending | stretching direction of a resin film are prescribed | regulated, and the consideration which makes less influence of a heat shrink when producing an ND filter is made.
However, this suppresses dimensional deviation due to thermal contraction, and does not take into consideration the warpage or cracks of the substrate accompanying the change in the substrate temperature described above.

  In view of the above problems, an object of the present invention is to provide an ND filter, a method for manufacturing an ND filter, and a light quantity reduction device that can suppress the occurrence of warpage, cracks, and the like of a substrate.

In order to solve the above-mentioned problems, the present invention provides an ND filter, an ND filter manufacturing method, and a light quantity diaphragm device configured as follows.
That is, the ND filter of the present invention is an ND filter that adjusts the amount of transmitted light, and the ND filter includes a laminated film on a resin base, and continuous or discontinuous ribs are formed on the base. It is characterized by.
The ND filter according to the present invention is characterized in that the rib is formed by plastic working.
Further, the ND filter of the present invention is characterized in that the ribs formed by plastic working are formed on the substrate before forming a laminated film on the substrate.
Further, in the ND filter of the present invention, the rib formed by the plastic working is constituted by a convex portion formed on one surface of the base body and a concave portion formed on the other surface of the base body corresponding to the convex portion. It is characterized by being.
Moreover, the ND filter of the present invention is characterized in that the rib is constituted by a convex portion formed by coating or printing on the substrate.
Moreover, the ND filter of the present invention is characterized in that the rib is constituted by a convex portion formed by bending an edge portion of the ND filter.
In addition, the ND filter of the present invention has a region where the transmittance is set to be uniform or a region where the transmittance continuously changes, and a visible region in the region where the transmittance is the lowest among the transmittances. The light transmittance is 10% or less.
The ND filter manufacturing method of the present invention is a ND filter manufacturing method for adjusting the amount of transmitted light, and has the following steps (1) and (2).
(1) A step of forming continuous or discontinuous ribs on a resin substrate by plastic working.
(2) A step of forming a laminated film composed of a light absorption layer and a dielectric layer on the substrate on which the rib is formed by vapor deposition.
The ND filter manufacturing method of the present invention is a ND filter manufacturing method for adjusting the amount of transmitted light, and has the following steps (1) and (2).
(1) A step of forming a laminated film composed of a light absorption layer and a dielectric layer on the substrate by vapor deposition.
(2) A step of forming continuous or discontinuous ribs made of convex portions by coating or printing on the substrate after forming a laminated film by the above step.
The ND filter manufacturing method of the present invention is an ND filter manufacturing method for adjusting the amount of transmitted light, and has the following steps (1) to (3).
(1) A step of forming a laminated film composed of a light absorption layer and a dielectric layer on the substrate by vapor deposition.
(2) A step of externally pressing the ND filter after forming the laminated film by the above step.
(3) A step of bending the edge of the ND filter from which the outer shape has been punched to form continuous or discontinuous ribs on the ND filter.
In addition, the light quantity diaphragm device according to the present invention includes the light quantity diaphragm device including the light quantity adjusting member including the ND filter manufactured by any one of the above ND filters or any one of the above ND filters. It is characterized by that.
The light amount diaphragm device is a light amount diaphragm device in which a transmission amount of a light beam transmitted through a predetermined opening is adjusted in accordance with a driving amount of the light amount adjustment member, and the light amount diaphragm device includes a light beam diaphragm device in a region where the light beam of the light amount diaphragm device is not transmitted. It is characterized in that the rib of the ND filter is positioned.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the ND filter and ND filter which can suppress generation | occurrence | production of the curvature of a base | substrate, a crack, etc. are realizable.
In addition, it is possible to realize a light quantity stop device including the ND filter and capable of suppressing image deterioration.

Next, the ND filter according to the embodiment of the present invention will be described with reference to the drawings while comparing with a conventional ND filter.
In FIG. 1, the schematic diagram of the ND filter in this embodiment is shown.
FIG. 2 shows a schematic diagram of a conventional ND filter.
First, it will be described how the conventional ND filter is used in the light quantity diaphragm device.
In FIG. 2, 21ND filter 22 is a diaphragm blade.
As shown in FIG. 2, the ND filter 21 is attached to a part of the diaphragm blade 22 in order to limit the amount of light passing through the optical system.
Here, the main reason for using a resin film without using glass as the ND filter substrate is that, as described above, the resin film is not easily broken even if it is thinner than glass, and the light quantity diaphragm can be made thinner and lighter. Because it becomes possible. In addition, the resin film can reduce the cost.

However, when forming an ND filter on a filter substrate made of such a resin film by vapor deposition, the substrate is warped after being deposited at a high substrate temperature as described above. Will occur.
Therefore, in the present embodiment, by providing continuous or discontinuous ribs on the resin film that is the base material, the occurrence of warpage, cracks, etc. of the substrate is suppressed.
In the ND filter of this embodiment shown in FIG. 1, an ND filter in which a continuous rib is provided on a resin film is bonded to a diaphragm blade.
In FIG. 1, an 11ND filter, 12 is a diaphragm blade, 13 is a rib, and 14 is an adhesive.
In the present embodiment, as described above, ribs are provided on the resin film when the ND filter is manufactured. However, the formation method and shape of the ribs are not particularly limited.
For example, as shown in FIG. 5 (a), the resin film may be hot-pressed to form ribs with uneven portions on the resin film.
As a result, the rib has a concave shape on one side and a convex shape on the opposite side, and can absorb the expansion and contraction caused by heat during the deposition, and cracks of the deposited film due to the expansion and contraction can be prevented.
Further, as shown in FIG. 5 (b), a UV curable resin may be applied or printed to form a rib with arcuate convex portions.
By forming the protrusions by coating or printing in this way, the material of the rib can be selected, and it becomes possible to form a stronger protrusion by increasing the thickness.
In addition, when the convex portions are formed, the flatness of the filter can be improved because the substrate and the vapor deposition film are not strained by plastic deformation or the like.
Further, as shown in FIG. 5 (c), after cutting into the final shape of the ND filter, a bending process may be performed to form a convex portion.

  According to this, the rib by the convex portion can be formed by bending the edge portion of the ND filter, and the occurrence of warpage, cracks, etc. of the substrate is suppressed while minimizing the space (volume) occupied by the convex portion. Is possible.

Next, a usage form of the ND filter of this embodiment will be described.
FIG. 3 shows a configuration of a photographing apparatus incorporating a light amount adjusting device using the ND filter in the present embodiment.
In FIG. 3, reference numerals 36A, 36B, 36C, and 36D denote lenses constituting the photographing optical system 36, 37 denotes a solid-state image sensor, and 38 denotes a low-pass filter.
Reference numerals 31 to 34 denote light quantity diaphragms, and reference numeral 31 denotes an ND filter.
Reference numerals 32 and 33 denote opposingly moving diaphragm blades, and a substantially diamond-shaped opening is formed by the two diaphragm blades.
The ND filter is usually bonded to the diaphragm blade. Reference numeral 34 denotes a diaphragm blade support plate.

Next, the transmittance pattern that can be taken in the ND filter of the present embodiment will be described.
FIG. 4A shows a state in which the size of the opening C is controlled by the blades operating alternately in the light amount adjusting device.
In FIG. 4A, reference numerals 32 and 33 denote diaphragm driving blades. In this case, the ND filter 31 is fixed to the 32 blades with an adhesive, and 33 is the other side to which the ND filter is not attached. It is a feather.
In the ND filter according to the present embodiment, as shown in FIGS. 4B to 4D, several transmittance distribution patterns can be adopted, and they are selectively used according to required specifications. For example, in FIG. 4B, the same transmittance is set from position 0 to X3.
In FIG. 4C, the transmittance changes stepwise from 0 to X3.
In FIG. 4D, the transmittance continuously changes from 0 to X3. Such a pattern is generally used, and in order to form a transmittance distribution within the filter surface, a method of changing the number of laminated films using a vapor deposition mask or changing the film thickness depending on the position is used.

The predetermined transmittance is obtained by forming a multilayer dielectric or metal film on one or both sides of the transparent resin film by vacuum deposition, ion plating, ion-assisted deposition, sputtering, or the like. The film structure of the laminated film as shown in FIG.
As the transparent resin film, a polyester film, a polyethylene film, a polypropylene film, a polystyrene film, a polyvinylidene chloride film, a polyethylene film, or the like is used. Alternatively, a polyethylene naphthalate film, a norbornene resin film, a polyimide resin film, or the like is used.

Next, an example of a method for manufacturing the ND filter in this embodiment will be described.
Here, a method for producing an ND filter with continuously changing transmittance as shown in FIG. 4D, or a case in which a rib is formed on a base material before vapor deposition will be described. It is not limited.
(1) First, a reference hole for fitting a reference pin provided in a vapor deposition jig is provided in a base material on which a rib is formed.
(2) The reference hole is fitted into the reference pin of the vapor deposition jig 50 shown in FIG. 8, the base material 90 is fixed to the vapor deposition jig 50, and the vapor deposition pattern forming mask 51 is set.
(3) The vapor deposition jig 50 is set in the vapor deposition apparatus 40, and the laminated film of FIG.
At this time, the necessary transmittance is adjusted by the film thickness of the laminated film. At the time of vapor deposition of the outermost layer, the vapor deposition pattern forming mask is removed, and the entire surface is formed with a constant film thickness under the condition of λλλ: 540 nm.
(4) When film formation of the outermost layer is completed, the film is taken out from the vapor deposition apparatus.
The extracted state becomes the state shown in FIG.
(5) After confirming the distance between the reference position for fixing the ND filter to the diaphragm blade and the density boundary portion, the outer shape is punched as shown in FIG.
(6) Adhere the pressed ND filter to the aperture blade as shown in FIG.
The above is the outline of the manufacturing process of the ND filter in the present embodiment.

According to the ND filter of the present embodiment, the amount of warpage can be reduced as compared with a conventional ND filter manufactured using a base material without a rib.
In addition, according to the ND filter of the present embodiment, the vapor deposition film can be formed thick, and the amount of warpage of the ND filter can be reduced even when a higher concentration ND filter is manufactured.
For example, a filter having a visible light transmittance of 10% or less can be created, and the image quality of the imaging device can be improved.
In particular, in the case where the rib is formed as shown in FIG. 5A before vapor deposition as described above, even if the vapor deposition film is thickened and the transmittance is lowered, the generation of wrinkles and cracks can be suppressed. .
In addition, a light quantity diaphragm device is manufactured using the ND filter of this embodiment, and the light quantity diaphragm device is incorporated in the photographing apparatus, whereby a high-quality photographing apparatus can be provided. For example, when the ND filter according to the present embodiment is incorporated into an imaging apparatus, the rib (convex portion) formed on the filter is configured to be positioned in a region where light flux does not transmit, so that an image by the rib (convex portion) is formed. Can be prevented.

Examples of the present invention will be described below, but the present invention is not limited to such examples.
[Example 1]
In Example 1, the resin film was hot-pressed to form uneven ribs shown in FIG.
As the resin film, 75 μm thick PET (polyethylene terephthalate) generally used as an ND filter was used.
The press mold shown in FIG. 6 was used for forming the rib. In order to form a concavo-convex rib on the press die, an upper die 61 provided with a convex portion and a lower die 62 provided with a concave portion were used, and the height of the concavo-convex portion was processed to 0.3 mm.
In forming the ribs, first, the press die is heated to 100 ° C., the resin film 80 is set between the press dies 61 and 62, and then sandwiched by the press dies to apply pressure.
Then, the press mold is opened and the resin film 80 on which the convex portions are formed is taken out.
Using the resin film 80 thus obtained as a base material 90, an ND filter was produced.

In this example, an ND filter in which the transmittance at the highest density portion was 6.3% and the transmittance was continuously changed was manufactured by the following procedure.
(1) First, a reference hole portion for fitting a reference pin provided in a vapor deposition jig was provided in a base material 90 provided with a convex portion on a resin film.
(2) The reference hole portion was fitted into the reference pin of the vapor deposition jig 50, the base material 90 was fixed to the vapor deposition jig, and the vapor deposition pattern forming mask 51 was set.
(3) The vapor deposition jig was set in the vapor deposition apparatus 40, and the 9-layer laminated film shown in FIG. At this time, the substrate heating temperature was set to 110 ° C., and the laminated film was formed with MgF ₂ as an outermost layer in an alternating layer of Al ₂ O ₃ and Ti ₂ O ₃ .
At this time, the film thickness of each layer was set so that the transmittance of the highest density portion was 6.3%. Further, when vapor-depositing MgF _{2 as} the outermost layer, the deposition pattern forming mask was removed, and the entire surface was formed with a constant film thickness under the condition of 1λ / 4λ: 540 nm.
(4) When film formation of the outermost layer was completed, the film was taken out from the vapor deposition apparatus. The extracted state becomes the state shown in FIG.
(5) The reference position for fixing the ND filter to the aperture blade was confirmed, and the outer shape was punched to the final dimension.
Similarly, ND filters having different transmittances of 25.1%, 12.6%, 10%, and 3.2% were prepared.

(Comparative example)
As a comparative example, an ND filter was produced in the same procedure as in the example using a resin film having no ribs on the substrate 90.
The ND filter thus obtained was bonded to the aperture blade, and the amount of warpage thereof was compared with that of the ND filter obtained in Example 1.
The dimensions of the ND filter produced at this time and the measuring method are shown in FIG. 10, and Table 1 shows a comparison result of the warpage amount of the ND filter.

As is clear from Table 1, the warpage amount of the ND filter is improved by providing ribs with the uneven portions on the base material.
In particular, the effect of the present embodiment is remarkable when the transmittance is 10% or less.
Further, the ribless ND filter produced as a comparative example generated cracks at a transmittance of 3.2%, but the ND filter produced according to Example 1 showed no cracks even at a transmittance of 3.2%. .

[Example 2]
In Example 2, a rib having the shape of FIG. 5B was formed by applying an ultraviolet curable acrylic resin using a dispenser after the formation of the deposited film.
In this embodiment, an acrylic resin is used, but the present invention is not limited to this.
For example, in addition to resins such as epoxy resin, melamine resin, phenol resin, polyethylene, polystyrene, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, ceramic or metal thick film pastes can be used.
As the rib forming method, spraying, screen printing, letterpress printing, intaglio printing, offset printing, ink jet printing and the like can be used in addition to coating.

In the present example, an ND filter was produced by the following procedure.
(1) First, a base material 90 was prepared by providing a reference hole for fitting a reference pin provided on a vapor deposition jig on a resin film.
(2) The reference hole portion was fitted into the reference pin of the vapor deposition jig 50, the base material 90 was fixed to the vapor deposition jig, and the vapor deposition pattern forming mask 51 was set.
(3) The vapor deposition jig was set in the vapor deposition apparatus 40, and the 9-layer laminated film shown in FIG. At that time, the substrate heating temperature was set to 110 ° C., and the laminated film was formed with MgF ₂ as an outermost layer in alternating layers of Al ₂ O ₃ and Ti ₂ O ₃ .
At this time, the film thickness of each layer was set so that the transmittance of the highest density portion was 6.3%. Further, when vapor-depositing MgF _{2 as} the outermost layer, the deposition pattern forming mask was removed, and the entire surface was formed with a constant film thickness under the condition of 1λ / 4λ: 540 nm.
(4) When film formation of the outermost layer was completed, the film was taken out from the vapor deposition apparatus.
(5) An ultraviolet curable acrylic resin was applied to the position where the convex portions of the substrate 90 were formed using a dispenser.
Thereafter, UV irradiation was performed under predetermined curing conditions to cure the acrylic resin. The convex part formed at this time was 0.7 mm in width and 0.5 mm in height.
(6) The reference position for fixing the ND filter to the aperture blade was confirmed, and the outer shape was punched to the final dimension.

In this embodiment, since the rib is formed by a member different from the base material, the thickness of the convex portion can be increased, and a stronger rib can be formed.
When the ND filter thus obtained was bonded to the diaphragm blade and the amount of warpage thereof was compared with Example 1, it was possible to further reduce the warpage as shown in Table 2.

When the ND filter produced in Example 1 and Example 2 described above is used as a light quantity adjusting member of a light quantity diaphragm device of a digital camera, it is better than that using an ND filter in which no rib (convex part) is formed. A good image was obtained.
In addition, the resin film used as the base material is often subjected to uniaxial stretching processing that stretches in one direction or biaxial stretching processing that stretches in two directions in order to increase mechanical strength. When heated, the film tends to warp in the stretching direction because of a large shrinkage in the stretching direction.
In the case of biaxial stretching, generally, the stretching force in the roll direction is strong and becomes main stretching, and the heat shrinkage is larger in the direction of main stretching than in the direction perpendicular thereto.
Therefore, if the direction of rib formation according to the present invention is also a stretching direction and a biaxial stretching, a greater effect is obtained when it is closer to the main stretching direction.

The schematic diagram of the ND filter in embodiment of this invention. The schematic diagram of the ND filter in a prior art example. The figure which shows the structure of the imaging device incorporating the light quantity adjustment apparatus using ND filter in embodiment of this invention. The figure explaining the transmittance | permeability pattern of the ND filter in embodiment of this invention. The figure which shows the structural example of the rib provided in the ND filter in embodiment of this invention. The figure explaining the press die used when forming a rib in the ND filter in Example 1 of this invention. The figure which shows the film | membrane structure of the laminated film in the ND filter in embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic of the vapor deposition apparatus and vapor deposition jig used when forming the ND filter in embodiment and Example of this invention. Schematic explaining the manufacturing method of the ND filter in Embodiment and the Example of this invention. The figure explaining the curvature amount comparison of the ND filter in Example 1 and a comparative example of this invention.

Explanation of symbols

11: ND filter 12: Diaphragm blade 13: Rib 14: Adhesive 36: Imaging optical systems 36A, 36B, 36C, 36D: Lens 32, 33: Diaphragm blade 34: Diaphragm blade support plate 37: Solid-state imaging device 38: Low-pass filter 40: Vapor deposition apparatus 41: Rotating dome 42: Vapor deposition source 50: Vapor deposition jig 51: Mask for vapor deposition pattern formation 61, 62: Press die 80: Resin film 90: Substrate

Claims (11)

  An ND filter for adjusting the amount of transmitted light, wherein the ND filter includes a laminated film on a resin base, and continuous or discontinuous ribs are formed on the base.   The ND filter according to claim 1, wherein the rib is formed by plastic working.   3. The ND filter according to claim 2, wherein the rib formed by the plastic working is formed on the base body before the laminated film is formed on the base body.   The rib formed by the plastic working is constituted by a convex portion formed on one surface of the base body and a concave portion formed on the other surface of the base body corresponding to the convex portion. Item 5. The ND filter according to Item 3.   The ND filter according to claim 1, wherein the rib is formed by a convex portion formed on the substrate by coating or printing.   The ND filter according to claim 1, wherein the rib is configured by a convex portion formed by bending an edge portion of the ND filter. The ND filter has a region set to a uniform transmittance or a region of a transmittance gradient in which the transmittance continuously changes,
The ND filter according to any one of claims 1 to 6, wherein a visible light transmittance in a region of the lowest transmittance among the transmittances is 10% or less. A method of manufacturing an ND filter that adjusts the amount of transmitted light,
Forming a continuous or discontinuous rib on a resin base by plastic working;
Forming a laminated film composed of a light absorption layer and a dielectric layer by vapor deposition on the rib-formed substrate;
A method for producing an ND filter, comprising: A method of manufacturing an ND filter that adjusts the amount of transmitted light,
Forming a laminated film composed of a light absorption layer and a dielectric layer on the substrate by vapor deposition;
Forming a continuous or discontinuous rib consisting of convex portions by coating or printing on the substrate after forming the laminated film by the step; and
A method for producing an ND filter, comprising: A method of manufacturing an ND filter that adjusts the amount of transmitted light,
Forming a laminated film composed of a light absorption layer and a dielectric layer on the substrate by vapor deposition;
After forming the laminated film by the above process, the process of punching out the ND filter by external press,
Bending the edge of the externally stamped ND filter to form continuous or discontinuous ribs on the ND filter;
A method for producing an ND filter, comprising: The light quantity adjusting member provided with the ND filter of any one of Claims 1-7, or the ND filter manufactured by the manufacturing method of the ND filter of any one of Claims 8-10, and this light quantity Drive means for driving the adjustment member,
A light amount diaphragm device in which a transmission amount of a light beam passing through a predetermined opening is adjusted according to a driving amount of the light amount adjustment member,
The light quantity diaphragm device is configured such that a rib of the ND filter is located in a region where the light flux of the light quantity diaphragm device is not transmitted.

Images