JP5217218B2 - Manufacturing method of absorption multilayer ND filter chip, absorption multilayer ND filter chip, joining method of absorption multilayer ND filter chip, diaphragm blade with absorption multilayer ND filter, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an absorptive multilayer ND filter that attenuates transmitted light in the visible light region, and a diaphragm blade with an absorptive multilayer ND filter for incorporating the absorptive multilayer ND filter in a camera. Manufacturing method of absorption multilayer ND filter chip and diaphragm blade with absorption multilayer ND filter, and joining method of absorption multilayer ND filter chip for joining absorption multilayer ND filter chip to diaphragm blade material It is about.

  As an ND (Neutral Density) filter, a reflection type ND filter that reflects and attenuates incident light and an absorption type ND filter that absorbs and attenuates incident light are known. In general, an absorption type ND filter is used when an ND filter is incorporated in the filter. In addition, the absorption type ND filter includes a type in which an absorbing substance is mixed in the filter substrate itself (colored glass ND filter), and a type in which the filter substrate itself has no absorption and a thin film formed on the substrate surface has absorption. In the latter case, in order to prevent reflection on the surface of the thin film, the thin film is formed of a multilayer film (absorption type multilayer film), and has an antireflection effect as well as a function of attenuating transmitted light.

  An absorption multilayer ND filter used in a small and thin digital camera requires a thin filter substrate because the installation space in the camera is narrow, and a resin film is an optimal filter substrate. As this type of absorption multilayer ND filter having a thin film formed of a multilayer film, Patent Document 1 discloses an ND filter composed of an oxide dielectric film and a metal film.

  In addition, when this type of ND filter including the ND filter is incorporated in a camera, an absorption multilayer film ND filter chip (absorption multilayer film ND) is usually provided on the diaphragm blade material 11 having an opening in the optical axis portion. For example, a diaphragm blade 30 with an absorption multilayer ND filter as shown in FIG. 6 is constructed, and the diaphragm blade 30 with an absorption multilayer ND filter is incorporated into the camera. ing.

  In order to manufacture a diaphragm blade with an absorption type multilayer ND filter, generally, an ND filter sheet composed of a resin film substrate and a multilayer film is press-cut to form an absorption type multilayer ND filter chip 20. The absorption multilayer ND filter chip 20 is bonded to the diaphragm blade material 11 to obtain the diaphragm blade 30 with the absorption multilayer ND filter. The diaphragm blade material 11 acts as an attachment frame for the absorption multilayer ND filter chip 20, and an opening is provided in the optical axis portion to which the absorption multilayer ND filter chip 20 is attached. Has been. Further, the diaphragm blade with the absorption multilayer ND filter is incorporated in the camera together with the diaphragm blade 31 not provided with a filter as shown in FIG. The diaphragm blades 31 that are not provided are moved in the direction of the arrows so that the ND filter is inserted into the optical axis portion as shown in FIG.

  By the way, when manufacturing the diaphragm blade 30 with the absorption multilayer film ND filter by joining the absorption multilayer film ND filter chip 20 to the diaphragm blade material 11, the joining means is generally a laser welding method, an ultrasonic wave. A welding method or an adhesive method using an adhesive is used. When the absorption multilayer film ND filter chip 20 is bonded to the diaphragm blade material 11 by these bonding methods, the absorption multilayer film exists on the resin film substrate of the absorption multilayer film ND filter chip 20, The resin film substrate and the diaphragm blade material 11 cannot be directly bonded, and the absorption multilayer film on the resin film substrate is directly bonded to the diaphragm blade material 11. In recent years, the adhesive strength of adhesives has improved, and the adhesive strength between the diaphragm blade material and the surface of the absorbent multilayer film by the adhesive has become stronger than the adhesive strength of the absorbent multilayer film to the resin film. Accordingly, the adhesion strength of the absorption multilayer ND filter depends on the adhesion strength between the resin film substrate and the absorption multilayer film in the absorption multilayer ND filter chip 20, and the resin film substrate and the absorption multilayer film. In general, there is a problem that the adhesion strength between the resin film substrate and the diaphragm blade material is lower than the adhesion strength when the resin film substrate and the diaphragm blade material are directly joined.

  Further, the absorption multilayer ND filter chip is obtained by press-cutting the absorption multilayer ND filter sheet as described above and processing it into a required shape of about 5 to 20 mm square. And since the absorption type multilayer film in which the oxide dielectric film was used as described in Patent Document 1 is hard like glass, the absorption type multilayer film is cracked by press cutting ( It has been pointed out that if a cracked film peels off and adheres to a driving part such as a shutter or an aperture, it causes a malfunction.

  Therefore, conventionally, a part of the resin film substrate 2 is covered with a mask 1 as shown in FIG. 8A during the formation of the absorption multilayer film, and as shown in FIG. A method of forming a film while hiding the portion from the vapor deposition source 4 is employed. According to this method, the absorption multilayer film 3 is formed only on the resin film substrate 2 exposed from the mask 1, and the cutting line 5 portion and the diaphragm blade material when press-cutting as shown in FIG. 8B. The absorptive multilayer film 3 is not formed at the joint portion or the like. Therefore, when the obtained absorption multilayer ND filter sheet is press-cut to obtain an absorption multilayer ND filter chip, the absorption multilayer ND filter sheet is taken along the cutting line 5 shown in FIG. Is cut, an absorptive multilayer film ND filter chip in which an undeposited portion is left around the absorptive multilayer film can be manufactured.

Patent Document 2 discloses a method of forming a film after masking the joint portion. And if this method is used, the absorption type multilayer film is not formed at the joint portion, and therefore the resin film substrate portion of the absorption type multilayer film ND filter chip is bonded to the diaphragm blade member by laser welding, ultrasonic welding or adhesive bonding. Therefore, the adhesion strength between the absorption multilayer ND filter chip and the diaphragm blade material is expected to be improved.
JP 2006-178395 A JP 2003-202612 A JP 2004-64028 A

  By the way, in the method of forming a film after masking the joint portion described in Patent Document 2, a large-area resin film substrate cannot be used to ensure the uniformity of the film thickness distribution of the absorption multilayer film. In practice, the production efficiency was poor because only batch production using a resin film substrate with a small area was possible. In this case, a method is also conceivable in which a long resin film substrate wound up in a roll shape is sequentially unwound and continuously formed on the resin film substrate using a roll coater while winding the resin film substrate. And although this method is excellent in productivity, it is difficult to fix the mask to the moving resin film substrate, so it is difficult to apply the mask process that leaves an undeposited part at the cutting line part or the joining part. Met.

  The present invention has been made paying attention to such problems, and the problem is that the cutting line portion of the absorption-type multilayer film or the diaphragm blade can be obtained by laser scribing without using a member such as the mask described above. By adopting a method of manufacturing an absorption type multilayer ND filter sheet from which a portion to be bonded to a material is removed, an absorption type multilayer ND filter chip having excellent productivity and a diaphragm blade with an absorption type multilayer ND filter And a method for bonding an absorption type multilayer ND filter chip for bonding an absorption type multilayer ND filter chip to an aperture blade material.

  In order to solve the above-mentioned problems, the present inventor removed a transparent conductive film of a liquid crystal display or the like, or a thin film removal method by laser irradiation known as a processing method of a substrate of a solar cell (may be referred to as laser scribing as described above). Tried to apply).

  That is, Patent Document 3 discloses a laser scribing method in which a removal portion is formed on a substrate main surface of a solar cell and this is used as a contact hole, and a laser beam is focused on the substrate surface to evaporate a part of the substrate material. Is disclosed. The laser beam can be focused on the substrate surface accurately and efficiently by well-known focusing servo control even if the substrate surface position varies, so multiple laser beams can be removed by scanning the surface of the semiconductor substrate. It is said that the part can be formed efficiently.

  Therefore, in the present invention, the laser scribing method is applied when manufacturing an absorption type multilayer ND filter chip, and a cutting line portion or aperture when press-cutting the ND filter sheet on which the absorption type multilayer film is formed. The part of the absorption multilayer film that becomes a joint portion with the blade material is removed.

That is, the invention according to claim 1
An absorptive multilayer ND filter chip is formed by press-cutting an absorptive multilayer ND filter sheet provided with an absorptive multilayer film formed by alternately laminating oxide dielectric films and metal films on at least one surface of a resin film substrate. Assuming a manufacturing method,
At least one absorption multilayer film of a cutting line portion or a portion to be joined with a diaphragm blade material when press-cutting the absorption multilayer film ND filter sheet has a pulse width of ns order with a top flat energy distribution . It is removed by a laser scribing method using an excimer laser.

The invention according to claim 2
Based on the manufacturing method of the absorption type multilayer ND filter chip according to the invention of claim 1,
The absorption multilayer film in the absorption multilayer film ND filter sheet is formed by a sputtering roll coater,
The invention according to claim 3
Based on the manufacturing method of the absorption multilayer ND filter chip according to the invention of claim 1 or 2,
The oxide dielectric film of the absorptive multilayer film in the absorptive multilayer ND filter sheet is composed of one or more films selected from SiO ₂ and Al ₂ O ₃ , and the metal film is Ni, Ti, Nb It is characterized by being comprised with the single-piece | unit film | membrane selected from Ta, Cr, or the alloy film which has these as a main component.

Next, the invention according to claim 4 is:
A collecting multilayer ND filter obtained by press-cutting an absorbing multilayer ND filter sheet provided with an absorbing multilayer film in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a resin film substrate Assuming a chip,
The surface of the resin film substrate which is manufactured by the method for manufacturing an absorption type multilayer ND filter chip according to claim 1, 2 or 3 and is exposed by removing the absorption type multilayer film by a laser scribing method becomes a polished glass. and features that you are,
The invention according to claim 5
Based on the method of joining the absorption type multilayer ND filter chip that joins the absorption type multilayer ND filter chip to the diaphragm blade material,
The absorption multilayer ND filter chip according to claim 4 is bonded to the diaphragm blade material by a method selected from a laser welding method, an ultrasonic welding method, and an adhesive method using an adhesive.

The invention according to claim 6
Assuming diaphragm blades with absorption multilayer ND filter,
An absorption multilayer ND filter chip according to claim 4, and an aperture blade material to which the absorption multilayer ND filter chip is bonded by a method selected from a laser welding method, an ultrasonic welding method, and an adhesive bonding method; It is composed of
The invention according to claim 7 provides:
Assuming the manufacturing method of diaphragm blades with absorption multilayer ND filter,
A diaphragm blade with an absorption type multilayer ND filter is manufactured using the method for joining absorption type multilayer ND filter chips according to claim 5.

According to the method for manufacturing an absorption-type multilayer ND filter chip according to the present invention,
An absorptive multilayer ND filter chip is formed by press-cutting an absorptive multilayer ND filter sheet provided with an absorptive multilayer film formed by alternately laminating oxide dielectric films and metal films on at least one surface of a resin film substrate. In the manufacturing method,
At least one absorption multilayer film of a cutting line portion or a portion to be joined with a diaphragm blade material when press-cutting the absorption multilayer film ND filter sheet has a pulse width of ns order with a top flat energy distribution . Since it is removed by a laser scribing method using an excimer laser, it is more productive than the conventional technique using a mask when forming an absorption multilayer film.

In addition, the diaphragm blade with an absorption multilayer ND filter according to the present invention is
An absorption multilayer ND filter chip manufactured by the above manufacturing method and having a polished glass surface on the surface of the resin film substrate exposed by removing the absorption multilayer by the laser scribing method, and the absorption multilayer ND filter The tip is composed of a diaphragm blade material joined by a method selected from a laser welding method, an ultrasonic welding method, or an adhesive bonding method, and the resin film substrate of the absorption multilayer ND filter chip and the diaphragm blade material are directly Since they are joined, the adhesion strength between the absorption-type multilayer ND filter chip and the diaphragm blade material is greatly improved.

Hereinafter, embodiments of the present invention will be described in detail.
(1) Film structure of absorption multilayer ND filter First, an absorption multilayer ND filter sheet according to the present invention includes a sheet-like resin film substrate and an oxide dielectric film and a metal on at least one surface of the resin film substrate. It is comprised with the absorption type multilayer film which laminates | stacks a film | membrane alternately.

The oxide dielectric film is exemplified by one or more films selected from SiO ₂ and Al ₂ O ₃ , and the metal film is a single film selected from Ni, Ti, Nb, Ta, and Cr. Or the alloy film which has these as a main component is illustrated.

As an example, the film configuration of an absorption multilayer ND filter having an average transmittance of 6.3% using Ni as the metal film and SiO ₂ as the oxide dielectric film is shown in Table 1 below. Further, FIG. 3 shows the spectral transmittance of the absorption multilayer ND filter having this film configuration.

Similarly, the film configuration of an absorption type multilayer ND filter having an average transmittance of 12.5% using Ni as the metal film and SiO ₂ as the oxide dielectric film is shown in Table 2 below. The spectral transmittance of the absorption multilayer ND filter having the configuration is shown in FIG.

Further, the film configuration of an absorption type multilayer ND filter having an average transmittance of 25.0%, which uses Ni as the metal film and SiO ₂ as the oxide dielectric film, is shown in Table 3 below. FIG. 5 shows the spectral transmittance of the absorptive multilayer ND filter.

  As is clear from the descriptions in Tables 1 to 3, the thickness of each Ni film is thinner as the absorption ND filter has a higher average transmittance.

（２）吸収型多層膜ＮＤフィルターチップの製造方法
（２−１）吸収型多層膜ＮＤフィルターシート（吸収型多層膜を具備するシート部材）
吸収型多層膜ＮＤフィルターを製造するには以下の２つの方法がある。

(2) Manufacturing method of absorption-type multilayer ND filter chip (2-1) Absorption-type multilayer ND filter sheet (sheet member provided with absorption-type multilayer film)
There are the following two methods for manufacturing an absorption-type multilayer ND filter.

  One of them is a method using a mask described in the prior art, that is, a batch-type film forming method in which a mask is superimposed on a resin film substrate cut into a plurality of sheets to form a film at once. However, the size of the resin film substrate is limited by the film thickness distribution in the resin film substrate.

  The other is a method adopted in the present invention.

  That is, a roll coater using a long resin film substrate wound in a roll shape is used. Since the method using a roll coater has a large film forming area that can be processed at one time, the productivity is clearly higher than that of the batch method. However, because it is extremely difficult to overlay a mask on a moving long resin film substrate, an absorption multilayer film is first formed on the entire surface of the long resin film substrate, and instead of using a mask, press A method is used in which at least one of the absorption-type multilayer films at the line portion at the time of cutting or the portion that becomes the joining portion with the diaphragm blade material is removed by laser scribing.

  The roll coater can form a film while bringing the resin film substrate into close contact with the water-cooled can roll. For example, in film formation by sputtering, since the resin film substrate is cooled, the thermal load can be reduced, so that a large amount of power can be input to the sputtering target, and the film formation rate can be improved. Moreover, since it is possible to obtain a time-stable film thickness in the transport direction (length direction) of the resin film substrate, the film thickness distribution in the width direction of the resin film substrate should be improved by a film thickness correction plate or the like. Thus, a uniform film thickness distribution can be obtained on the entire surface, whereby uniform optical characteristics can be obtained.

  In film formation by a roll coater, first, surface treatment such as plasma or ion beam is performed while the resin film substrate is transported in order to increase the adhesion between the absorption multilayer film and the resin film substrate.

Next, a first-layer oxide dielectric film is formed, and then a second-layer metal film is formed while reversing the transport direction of the resin film substrate. These steps are repeated until the fifth layer is formed, and then the resin film substrate is turned over, and a similar absorption multilayer film is formed on the back surface. It should be noted that it is naturally possible to form two layers of the oxide dielectric film and the metal film at the same time in one transport by appropriately controlling the differential exhaust of the film formation chamber and the film formation speed. Alternatively, two can rolls may be disposed on the front and back surfaces of the absorption multilayer film at the same time.
(2-2) Laser scribing of absorption-type multilayer ND filter sheet The absorption-type multilayer film of the portion 7 that becomes the joining portion between the cutting line 5 portion and the diaphragm blade material during press cutting is removed by laser scribing. A plan view of the absorption type multilayer ND filter sheet is shown in FIG.
(A) Press cutting For press cutting, there are a method of completely cutting off by a mold and a half-cut press method in which the laminate sheet is laminated without laminating the absorbent multilayer ND filter sheet on the laminate sheet. is there.

  The width of the portion 6 of the absorption multilayer film to be removed by laser scribing in the cutting line 5 is suitably about 0.1 to 2 mm. If the diaphragm blade material can be joined at the portion 6 of the cutting line 5 from which the absorbing multilayer film has been removed, it is not necessary to remove the absorbing multilayer film by laser scribing for joining. Further, in order to remove the absorption multilayer film on both surfaces of the absorption multilayer film ND filter sheet, laser scribing may be performed while aligning one surface at a time, or laser scribing may be performed simultaneously on both surfaces.

Further, if cracks in the absorption multilayer film near the cutting line 5 due to press cutting do not become a problem, it is needless to say that it is not necessary to laser scribe the portion 6 of the absorption multilayer film in the cutting line 5, and the diaphragm blade material Only the absorptive multilayer film of the portion 7 which becomes the bonding site with the laser may be laser scribed.
(B) Laser scribing In order to perform the above laser scribing, it is necessary to optimize laser irradiation conditions. When the laser irradiation energy density is low and the laser irradiation time is long, the absorption multilayer film is heated without being sublimated, and before the dielectric oxide film and the metal film constituting the absorption multilayer film are sublimated, the melting point becomes It is predicted that the resin film substrate itself, which is much lower, melts and opens, or carbonizes.

  Accordingly, it is necessary to set the laser irradiation time short and to determine the laser irradiation conditions that can sublimate and remove the absorption multilayer film without affecting the resin film substrate.

Further, the criteria for selecting a laser to be used for laser scribing include a laser wavelength, a pulse width, the number of repetitions, and the number of irradiations. Currently, a wide variety of lasers have been developed, and it is possible to select from these. For example, an excimer laser with a pulse width of ns order (ArF laser: wavelength 193 nm, KrF laser: 248 nm), a YAG laser with a pulse width ps to ns order (fundamental wave 1064 nm, second harmonic 532 nm, third harmonic: 355 nm, Fourth harmonic: 266 nm), a titanium sapphire laser with a pulse width of fs to ps order, etc., and an excimer laser with a pulse width of ns order having a top flat type energy distribution is selected in the embodiment. Here, fs, ps, and ns mean fs: 10 ⁻¹⁵ seconds, ps: 10 ⁻¹² seconds, and ns: 10 ⁻⁹ seconds, respectively.

  In laser scribing, the energy distribution of the laser beam is also an important factor. The energy distribution of the laser is broadly divided into a Gaussian distribution type and a top hat type (also referred to as a top flat type or a flat top type) in which the energy distribution in the peripheral part and the central part is almost uniform. The laser used for laser scribing is advantageously a laser having a top flat energy distribution. If the energy distribution of the laser beam is a Gaussian distribution type, if the laser output is increased in order to efficiently perform laser scribing around the low energy beam, the energy at the center of the beam becomes too high and the irradiation center There may be holes or carbonization.

  Furthermore, the portion where the absorption multilayer film of the absorption multilayer film ND filter sheet is removed by laser scribing and the resin film substrate is exposed has a rough and polished glass surface. It can also be expected to improve adhesive strength due to the effect. In many cases, the resin film substrate exposed by laser scribing may be somewhat turbid even if the surface is somewhat roughened and polished to a glass shape due to laser damage. Incident light is not always transmitted through the ND filter incorporated in the camera, and the optical characteristics are rarely required for the part of the cutting line to be press-cut and the part of the joint part with the diaphragm blade material. Because.

  Further, the removal process of the absorption multilayer film by laser scribing may be performed after the produced long absorption multilayer film ND filter is cut into a sheet to obtain an ND filter sheet, or After forming an absorption type multilayer film on a long resin film substrate, it may be optionally performed by laser scribing continuously in a long shape.

  Here, although the material which comprises a resin film board | substrate is not specifically limited, A transparent thing is preferable and when considering mass productivity, it is preferable that it is a flexible board | substrate which can form into a film with a dry-type sputtering roll coater. The flexible substrate is excellent in that it is cheaper, lighter and more deformable than a conventional glass substrate. It is also suitable for press cutting.

  As specific examples of the resin film constituting the substrate, the resin film selected from polyethylene terephthalate (PET), polyethersulfone (PES), polyarylate (PAR), polycarbonate (PC), polyolefin (PO) and norbornene. Or a composite of a single resin film selected from the above resin materials and an acrylic organic film covering one or both sides of the single resin film. In particular, with respect to norbornene resin materials, representative examples include ZEONOR (trade name: registered trademark) of Nippon Zeon Co., Ltd. and Arton (trade name: registered trademark) of JSR Corporation.

(3) Manufacturing Method of Diaphragm Blade Material (3-1) Diaphragm Blade Material An example of the diaphragm blade material 11 and the absorption multilayer ND filter chip 20 bonded to the diaphragm blade material 11 is shown in FIG. An absorption multilayer ND filter sheet that has been press-cut into small pieces is referred to as an absorption multilayer ND filter chip. A diaphragm blade material that also acts as a frame for fixing the chip is generally a black resin film. Is used. There are a method of mixing a pigment into a resin to form a black resin film, and a method of applying a black paint on the surface of a transparent resin film, or forming a black film and performing a black treatment so as not to transmit light. In addition, this diaphragm blade material has an opening or a cut in the optical axis portion to which the absorption multilayer ND filter chip is attached.

  There are two types of diaphragm blades for joining the absorption type multilayer ND filter chip. One of them is the function of blocking the luminous flux by the shape of the diaphragm blades and attenuating the light quantity continuously. When this function alone cannot attenuate the light quantity, an absorption multilayer ND filter chip is inserted into the optical axis. It is a structure. The other is that the diaphragm blade itself to which the absorption type multilayer ND filter chip is bonded does not have a function of continuously attenuating the amount of light, but simply functions as a frame of the absorption type multilayer ND filter chip, and the amount of light is continuous. This structure is combined with another diaphragm that can be attenuated automatically.

As described above, there is a member that does not function as a diaphragm blade that continuously attenuates the amount of light but functions only as a frame for fixing a simple absorption multilayer ND filter chip as described above. It is included in the diaphragm blade material according to the present invention.
(3-2) Bonding of absorption type multilayer ND filter chip and diaphragm blade material The method of bonding the absorption type multilayer film ND filter chip and diaphragm blade material includes laser welding, ultrasonic welding, or an adhesive method. It is necessary to remove the absorption multilayer film in a shape suitable for each bonding method. And when joining by laser welding, since the spot diameter of the laser is about 0.5 mm to 1.5 mm, the portion 7 of the absorption multilayer film that becomes the joining portion with the diaphragm blade material is slightly larger than the above size. It is desirable to remove (circular shape is illustrated in FIGS. 1 and 2). In the case of bonding with an adhesive, the absorption multilayer film only on the bonding surface side of the absorption multilayer film ND filter chip may be removed. However, in the case of bonding by laser welding, the absorption multilayer film ND It is desirable to remove the absorption multilayer film on both sides as well as on one side of the filter chip. If only the absorption multilayer film at the joint with the diaphragm blade material is removed, laser welding from the absorption multilayer film side that is not the bonding surface will absorb the laser energy on the side where the absorption multilayer film is not removed. This is because it is not preferable.

  Next, specific examples of the present invention will be described.

  In this embodiment, a film forming material (target) containing Si as a main component is used for forming the oxide dielectric film of the absorption multilayer ND filter, and a film containing Ni as the main component is used for forming the metal film. A film material (target) was used.

  A sputtering roll coater was used to form the absorption multilayer film, and a turbo molecular pump was used as the exhaust pump.

The SiO ₂ film was formed by using a target mainly composed of Si, introducing Ar gas at 150 sccm, performing sputtering by a dual magnetron sputtering method at a sputtering power of 10 kW, and controlling oxygen introduction by an impedance monitor. The smaller the impedance control set value is, the more oxygen is introduced.

  Note that dual magnetron sputtering is a sputtering method that suppresses the occurrence of arcing by alternately applying medium frequency (40 kHz) pulses to two targets to form an insulating film at high speed, thereby preventing the formation of an insulating layer on the target surface. Is the method.

  In addition, the impedance monitor applies the phenomenon that the impedance between the target electrodes changes depending on the amount of oxygen introduced, and oxygen is introduced so that the film to be formed becomes a desired film in the transition region between the metal mode and the oxide mode. It is used to control and monitor the amount to form an oxide dielectric film at high speed.

  A film formed using a target containing Si as a main component has an oxide dielectric film indicated by SiOx as the oxygen partial pressure during film formation increases (the amount of oxygen introduced during film formation increases). The X value changes to 2 and changes from a colored film to a transparent film.

  On the other hand, the metal film is formed by DC sputtering using a target containing Ni as a main component, and oxygen is not introduced. Ar gas was introduced at 150 sccm, and a film was formed at a sputtering power of 500 W.

  The resin film constituting the substrate was a PET film having a thickness of 100 μm, a width of 300 mm, and a length of 100 m. Prior to film formation, plasma treatment is performed in vacuum in order to increase the adhesion of the absorption multilayer film.

  And the absorption type multilayer ND filter of the film | membrane structure shown in said Table 1 was manufactured. First, a five-layer film was formed on the front surface, and then the film was turned over and a similar five-layer film was formed on the back surface.

  Next, the obtained absorption multilayer ND filter was cut into a sheet shape by cutting at 300 mm intervals, and laser scribing was performed after the absorption multilayer ND filter sheet was formed.

  For laser scribing, a 30 mJ output of a KrF excimer laser (laser wavelength: 248 nm, pulse width 20 ns, repetition rate: 100 Hz) was used. A projection optical system was used for condensing the beam to form a circular beam with a diameter of 1 mm. The energy distribution of the KrF excimer laser beam is a top hat type. One-side absorption multilayer film could not be completely removed by one pulse irradiation, but one-side absorption multilayer film should be completely removed into a circular shape having a diameter of 1 mm by two or more pulse irradiations. The surface of the PET film as a substrate appeared. In addition, the circular exposure site | part in PET film respond | corresponds to a joining site | part with an aperture blade material.

  Pulse irradiation was also performed on the back side corresponding to the part removed in a circular shape, and the absorption multilayer film could be removed in a circular shape having a diameter of 1 mm on both sides. Further, the surface of the PET film from which the absorption multilayer film was removed was somewhat roughened polished glass.

  Next, the laser is operated at 10 Hz, and the absorption multilayer film ND filter sheet is moved at 1 mm / second while irradiating the absorption multilayer film, thereby completely removing the absorption multilayer film in a straight line having a width of 1 mm. I was able to. The exposed portion of the PET film removed in a straight line having a width of 1 mm corresponds to the press cutting line portion of the absorption multilayer ND filter sheet.

  Here, laser scribing was also possible using a titanium sapphire laser (laser wavelength: 790 nm, pulse width 150 fs, repetition rate: 2 kHz, output: 250 mW). In addition, when laser scribing is performed while a gas such as nitrogen, helium, or Ar is blown onto the laser irradiated portion, reattachment of the removed film component can be prevented.

[Evaluation]
Observation of cracks in the absorption multilayer film by press cutting of the portion where the absorption multilayer film is linearly removed by laser scribing, and a portion where the absorption multilayer film is removed in a circular shape having a diameter of 1 mm by laser scribing The present invention was evaluated by a joining test in which a black PET plate as a diaphragm blade material was joined by an adhesive and laser welding.
(1) First, a laminate film having a thickness of 100 μm is pasted on both sides of an absorption multilayer film ND filter sheet from which both sides of the absorption multilayer film are linearly removed with a width of 1 mm, and the lower laminate film is completely Punching was performed with a half-cut press that did not punch. In the portion that has been punched by this half-cut press, there is no absorptive multilayer film, so no cracking occurs.

Similarly, when a punching process using a half-cut press is performed on a portion where an absorption multilayer film not subjected to laser scribing is present, a fine crack is formed within a range of 100 to 150 μm from the cutting position of the absorption multilayer film. Cracks occurred. It has been pointed out that if these cracked absorption type multilayer films are peeled off and adhere to driving parts such as a shutter and an aperture, it causes a malfunction.
(2) Next, the circular part of the absorption multilayer film ND filter sheet from which the absorption multilayer films on both sides are removed in a circular shape having a diameter of 1 mm is used as an aperture blade material by using an epoxy ultraviolet curing resin. Bonded to a black PET plate.

  And when the adhesion part of the absorption type multilayer ND filter sheet and the black PET board was pulled in the 90 ° direction and the adhesion strength was measured, it was about 200 g.

  Here, the adhesive was not peeled off on the surface of the PET film from which the absorption multilayer film was removed in a circular shape by laser scribing, but was peeled off on the surface of the black PET plate as the diaphragm blade material. From this, the surface where the PET film as the resin film substrate is exposed by laser scribing becomes polished glass, and due to its anchor effect, the adhesive force of the epoxy UV curable resin is stronger than the black PET plate as the diaphragm blade material It is thought that it became.

  Similarly, a portion where an absorption type multilayer film not subjected to laser scribing was also adhered to a black PET plate and its tensile adhesive strength was measured, and it was about 100 g.

The absorptive multilayer film of the absorptive multilayer film ND filter sheet was peeled off at the PET film interface as a resin film substrate. From this, the adhesive strength of the diaphragm blade material (black PET board) and the absorption multilayer film with the epoxy UV curable resin was stronger than the adhesion between the absorption multilayer film and the resin film substrate. Is suggested.
(3) Finally, the circular portion of the absorption multilayer film ND filter sheet from which the absorption multilayer films on both sides were removed in a circular shape with a diameter of 1 mm was joined to a black PET plate as a diaphragm blade material by laser welding. . A semiconductor laser having a wavelength of 980 nm and an output of 10 W was used as the laser welding laser.

  And when the adhesion part of the absorption type multilayer ND filter sheet and the black PET board was pulled in the 90 ° direction and the adhesion strength was measured, it was about 200 g.

Similarly, laser welding is performed on a portion where an absorption-type multilayer film not subjected to laser scribing is present, and when the tensile adhesive strength is measured, the tensile adhesion strength is about 20 g or less, which is hardly joined. It was in a state. When observing the joint with a microscope, the PET film as the resin film substrate and the black PET film as the diaphragm blade material are in a melted state, but between these resin film substrate and the diaphragm blade material. It is presumed that the film could not be adhered due to being blocked by the absorption type multilayer film present in the film.
(4) In this way, the absorption multilayer film is removed by laser scribing, and no cracking occurs in the absorption multilayer film due to the press cutting process of the portion where the resin film substrate is exposed. The superiority of the present invention was confirmed because the adhesiveness of the exposed part and the bonding property to the diaphragm blade material by laser welding were also excellent.

  The manufacturing method of the absorption-type multilayer ND filter chip according to the present invention is excellent in productivity, and the bonding method of the obtained absorption-type multilayer ND filter chip to the diaphragm blade material is also excellent in bonding properties. The diaphragm blade with an absorption-type multilayer ND filter according to the present invention has industrial applicability for use in small thin digital cameras and camera-equipped mobile phones that require long-term reliability in harsh environments. doing.

The top view of the absorption multilayer film ND filter sheet which concerns on this invention from which the absorption multilayer film of the part used as the junction part of a cutting line part and an aperture blade material was removed by laser scribing. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a diaphragm blade material according to the present invention and an absorption multilayer ND filter chip bonded to the diaphragm blade material. The graph which shows the spectral transmission characteristic of the absorption type multilayer ND filter which concerns on this invention. The graph which shows the spectral transmission characteristic of the absorption type multilayer ND filter which concerns on this invention. The graph which shows the spectral transmission characteristic of the absorption type multilayer ND filter which concerns on this invention. Explanatory drawing of the aperture blade with an absorption type multilayer film ND filter integrated in a camera, and the aperture blade which does not comprise a filter. Action | operation explanatory drawing of the aperture blade with said absorption type multilayer ND filter and the aperture blade which does not comprise a filter. FIG. 8A is a plan view of a mask used when forming an absorption multilayer film in the prior art, and FIG. 8B is a plan view of an absorption multilayer ND filter sheet obtained by the conventional technique. Explanatory drawing of the film-forming method of the absorption type multilayer film which concerns on the prior art example which manufactures an absorption type multilayer ND filter sheet using a mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mask 2 Resin film substrate 3 Absorption type multilayer film 4 Evaporation source 5 Cutting line 6 Cutting line part 7 Part used as a junction part with an aperture blade material 11 Diaphragm blade material 20 Absorption type multilayer film ND Filter chip 30 Absorption type multilayer film ND Diaphragm blade with filter 31 Diaphragm blade without filter

Claims (7)

An absorptive multilayer ND filter chip is formed by press-cutting an absorptive multilayer ND filter sheet provided with an absorptive multilayer film formed by alternately laminating oxide dielectric films and metal films on at least one surface of a resin film substrate. In the manufacturing method,
At least one absorption multilayer film of a cutting line portion or a portion to be joined with a diaphragm blade material when press-cutting the absorption multilayer film ND filter sheet has a pulse width of ns order with a top flat energy distribution . A method for producing an absorptive multilayer ND filter chip, which is removed by a laser scribing method using an excimer laser.   2. The method for producing an absorption multilayer ND filter chip according to claim 1, wherein the absorption multilayer film in the absorption multilayer ND filter sheet is formed by a sputtering roll coater. The oxide dielectric film of the absorptive multilayer film in the absorptive multilayer ND filter sheet is composed of one or more films selected from SiO ₂ and Al ₂ O ₃ , and the metal film is Ni, Ti, Nb 3. The method for producing an absorptive multilayer ND filter chip according to claim 1 or 2, comprising a single film selected from Ta, Cr, or an alloy film containing these as a main component. A collecting multilayer ND filter obtained by press-cutting an absorbing multilayer ND filter sheet provided with an absorbing multilayer film in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a resin film substrate In the chip ,
The surface of the resin film substrate which is manufactured by the method for manufacturing an absorption type multilayer ND filter chip according to claim 1, 2 or 3 and is exposed by removing the absorption type multilayer film by a laser scribing method becomes a polished glass. absorption type multi-layer film ND filter tip, characterized in that there.   An absorptive multilayer ND filter chip according to claim 4, wherein the absorptive multilayer ND filter chip is joined to a diaphragm blade material by a method selected from a laser welding method, an ultrasonic welding method, and an adhesive method. How to join filter tips.   An absorption multilayer ND filter chip according to claim 4, and an aperture blade material to which the absorption multilayer ND filter chip is bonded by a method selected from a laser welding method, an ultrasonic welding method, and an adhesive bonding method; An aperture blade with an absorption-type multilayer film ND filter, comprising:   A manufacturing method of an aperture blade with an absorption type multilayer ND filter, wherein the aperture blade with an absorption type multilayer ND filter is manufactured using the method for bonding an absorption type multilayer ND filter chip according to claim 5.

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