JP2007041347A - Optical multilayer film filter and method for manufacturing optical multilayer film filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multilayer film filter which prevents the occurrence of warping of a substrate due to an inner stress of a dielectric multilayer film and has a high-performance optical characteristic capable of preventing the occurrence of peeling, cracking and the like of the dielectric multilayer film or optical distortion, and to provide a method for manufacturing the optical multilayer film filter. <P>SOLUTION: The optical multilayer film filter has a resin layer 3 made of a photo-polymerizable resin, formed on one side surface of a glass substrate 2. The resin layer 3 comprises: a region 3b where the photo-polymerizable resin formed along a peripheral part of the substrate surface is cured by light energy irradiation; a liquid region 3c of the photo-polymerizable resin; and a region 3d where a part in contact with the lowermost layer part of the dielectric multilayer film of the liquid region 3c of the photo-polymerizable resin is cured by femto-second laser pulse beam irradiation. A dielectric multilayer film where two kinds of films having different refractive indexes are alternately stacked is formed on the resin layer 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical multilayer filter such as an antireflection film and a half mirror used for optical components, and a method for manufacturing the optical multilayer filter.

2. Description of the Related Art Conventionally, an optical multilayer filter having a predetermined filter characteristic by alternately forming a large number of high refractive index material layers and high refractive index material layers on a glass substrate is known. Such an optical multilayer filter is a glass substrate that is distorted due to an internal stress generated by a difference in thermal expansion coefficient between the glass substrate and the multilayer film formed on the glass substrate, or the film formed on the glass substrate is peeled off. Etc. occur.
An optical multilayer filter is usually formed by sputtering, vacuum deposition, or the like. The internal stress of the formed thin film layer is such that the tensile stress in the direction in which the film tends to shrink and the film spreads. Compressive stress. The glass substrate on which the film is formed has a concave shape when the internal stress of the film is a tensile stress, and has a convex shape when the stress is compressive.

  In order to cope with such a problem, an optical multilayer filter (for example, a patent) in which a buffer layer formed by selecting a material and a film thickness for relaxing the internal stress of the optical multilayer film is interposed between the substrate and the optical multilayer film. Reference 1), or an optical thin film formed by using a film material in which at least two types of films having different refractive indexes are alternately stacked on a substrate and the internal stresses of adjacent films cancel each other. It has been proposed (see, for example, Patent Document 2).

JP-A-8-262224 JP 2003-277911 A

However, the buffer layer described in Patent Document 1 needs to be formed with a considerable number of film thicknesses in order to obtain the effect of relieving the internal stress of the multilayer film. Scattering is likely to occur. In addition, the optical thin film described in Patent Document 2 has a multilayer film in which thin films having compressive stress as internal stress and thin films having tensile stress as internal stress are alternately laminated, thereby reducing the internal stress of the entire multilayer film. Although the surface of the substrate is rarely distorted, there is a concern that film peeling tends to occur between the substrate and the first layer thin film in contact with the substrate.
Therefore, the present invention has been made in view of such circumstances, and prevents the warpage of the substrate due to the internal stress of the dielectric multilayer film, as well as the occurrence of peeling of the dielectric multilayer film, the occurrence of cracks, or the like. An object of the present invention is to provide an optical multilayer filter having high-performance optical characteristics that prevents the occurrence of distortion, and a method for manufacturing the optical multilayer filter.

In order to solve the above-described problems, an optical multilayer filter of the present invention is an optical multilayer filter having a dielectric multilayer film in which at least two kinds of films having different refractive indexes are alternately laminated on a substrate. A resin layer that absorbs internal stress of the dielectric multilayer film is formed between the dielectric multilayer films.
According to this, due to the resin layer formed between the substrate and the dielectric multilayer film (surface of the substrate), the internal stress of the dielectric multilayer film formed on the resin layer spreads to the resin layer, thereby The stress is absorbed by the resin layer, and the occurrence of warpage of the substrate can be prevented. By preventing the occurrence of warping, an optical multilayer film filter having high performance optical characteristics in which the dielectric multilayer film is prevented from being peeled off, cracks, etc., or optical distortion can be obtained.

  In the optical multilayer filter of the present invention, the resin layer is made of a photopolymerizable resin, and the photopolymerizable resin formed along the peripheral edge of the surface of the substrate is irradiated with active energy rays and cured. And a liquid region of the photopolymerizable resin, and a region where a portion in contact with the lowermost layer portion of the dielectric multilayer film is cured by irradiation with a femtosecond laser pulse beam.

  According to this, the resin layer formed between the substrate and the dielectric multilayer film (substrate surface) is made of a photopolymerizable resin, and is formed along the peripheral edge of the substrate surface by irradiating active energy rays. A cured region of the photopolymerizable resin, a liquid region of the photopolymerizable resin, and a region where the portion contacting the lowermost layer of the dielectric multilayer film is cured by irradiation with a femtosecond laser pulse beam. As a result, the film stress (internal stress) due to the dielectric multilayer film formed on the resin layer spreads to the liquid region (uncured region), so that the film stress is absorbed into the liquid region and the substrate warps. Can be prevented.

In the optical multilayer filter of the present invention, the liquid region of the photopolymerizable resin includes the substrate, a region where the photopolymerizable resin is cured by irradiating the active energy ray, and the dielectric multilayer film. A portion in contact with the lowermost layer portion is gripped by a hardened region.
According to this, the liquid region of the photopolymerizable resin is the region where the substrate, the region where the photopolymerizable resin is cured by irradiating the active energy ray, and the portion where the lowermost portion of the dielectric multilayer film is cured Is held on the substrate, and the film stress (internal stress) due to the dielectric multilayer film formed on the resin layer spreads to the liquid region (uncured region). As a result, the film stress is absorbed in the liquid region, and the occurrence of warping of the substrate can be prevented.

  The method for producing an optical multilayer filter of the present invention is a method for producing an optical multilayer filter having a dielectric multilayer film in which at least two kinds of films having different refractive indexes are alternately laminated on a substrate, A coating step of forming a coating layer made of a photopolymerizable resin on the surface of one surface of the substrate, a region cured by irradiating active energy rays to the coating layer along the peripheral edge of the substrate, and the photopolymerization An active energy ray irradiating step for forming a liquid region of the conductive resin; a laser irradiating step for irradiating the liquid region with a femtosecond laser pulse beam and curing a portion in contact with the lowermost layer portion of the dielectric multilayer film; A resin layer is formed, and the dielectric multilayer film is formed on the resin layer.

  According to this manufacturing method, a region formed by irradiating the coating layer along the peripheral edge of the substrate with active energy rays and curing the coating layer made of a photopolymerizable resin formed on the surface of one surface of the substrate; By forming a liquid region of the photopolymerizable resin, and further irradiating the liquid region with a femtosecond laser pulse beam to cure the portion in contact with the lowermost layer portion of the dielectric multilayer film, thereby forming a resin layer The liquid region of the resin layer is held on the surface of the substrate, and the internal stress due to the dielectric multilayer film formed on the resin layer spreads to the liquid region, so that the internal stress is absorbed by the liquid region. Thus, an optical multilayer filter that prevents the substrate from warping can be obtained. In addition, the resin layer formation process can be separated from the dielectric multilayer film formation process that requires a long film formation time, for example, by adding it to the substrate manufacturing process. Efficient production can be performed without increasing the volume.

Hereinafter, embodiments of the optical multilayer filter of the present invention will be described.
The optical multilayer filter of the present embodiment, for example, has a reflection characteristic that transmits light in the visible wavelength range and has less absorption of light in an ultraviolet wavelength range of a predetermined wavelength or less and an infrared wavelength range of a predetermined wavelength or more. This is an example of application to a so-called UV-IR cut filter (Ultraviolet-Infrared cut filter).

FIG. 1 is a schematic cross-sectional view for explaining a film configuration formed in the optical multilayer filter of the present invention.
In FIG. 1, an optical multilayer filter 1 includes a glass substrate 2 as a substrate that transmits light, a resin layer 3 and a high refractive index material layer on one surface of the glass substrate 2 in this order from the surface of the glass substrate 2. A dielectric multilayer film 4 in which H and low refractive index material layers L are alternately laminated is formed.

The glass substrate 2 is made of white glass (transmittance, n = 1.52). For example, the flat surface has a rectangular shape of about 50 mm and a plate thickness of about 0.5 mm.
The resin layer 3 is a buffer layer for preventing the glass substrate 2 from warping due to internal stress of the dielectric multilayer film 4 formed on the upper layer of the resin layer 3, and is a thin film made of a photopolymerizable resin. Is a layer. As the photopolymerizable resin, for example, a transparent ultraviolet curable resin having a curing temperature of 180 ° C. or higher is used. As the ultraviolet curable resin, a polyimide resin or an epoxy resin can be preferably used.

A method for manufacturing the optical multilayer filter 1 configured as described above will be described.
In the optical multilayer filter 1, the resin layer 3 is formed on the surface of one surface of the glass substrate 2 in advance before the formation of the dielectric multilayer film 4.

  FIG. 2 is a schematic cross-sectional view of a glass substrate showing an embodiment of a resin layer forming step, (a) showing a glass substrate after the coating step, (b) showing a glass substrate in an ultraviolet irradiation step, (c ) Shows the glass substrate after the ultraviolet irradiation step, (d) shows the glass substrate in the laser irradiation step, and (e) shows the glass substrate after the resin layer is formed. FIG. 3 is a schematic configuration diagram of the laser irradiation apparatus. In the schematic cross-sectional view shown in FIG. 2, the dimensions and ratios of the constituent elements are different from the actual ones for convenience of explanation.

The resin layer 3 is formed through an application process, an ultraviolet irradiation process as an active energy ray irradiation process, and a laser irradiation process.
First, as shown in FIG. 2A, in the coating step, an ultraviolet curable resin as a photopolymerizable resin is coated on the surface of one surface of the glass substrate 2 to form a coating layer 3a. As the ultraviolet curable resin, for example, a transparent epoxy resin having a curing temperature of 180 ° C. or higher is used.

The application method of the ultraviolet curable resin is performed, for example, by a spin coating method. By using the spin coating method, the thickness of the coating layer 3a to be applied can be easily controlled. The film thickness of the coating layer 3a to be formed is formed in a range of about 0.01 to 10 μm. The ultraviolet curable resin can appropriately include a silane coupling agent, a polymerization initiator, and the like, which are components for imparting adhesion between the glass substrate 2 and the resin layer 3.
And the glass substrate 2 in which the coating layer 3a was formed transfers to an ultraviolet irradiation process.

In the ultraviolet irradiation process, ultraviolet rays are irradiated only to the region along the peripheral edge of the surface of the glass substrate 2 that is outside the predetermined optical effective region used as the optical multilayer filter.
In the ultraviolet irradiation, as shown in FIG. 2B, a mask 5 having an opening 5a formed in a region outside a predetermined optical effective region is disposed on the glass substrate 2 on which the coating layer 3a is formed. The Then, UV UR as an active energy ray generated from a high-pressure mercury lamp provided in an ultraviolet irradiation apparatus (not shown) is locally irradiated from the upper surface side of the mask 5 toward the opening 5a (coating layer 3a) of the mask 5. Is done. The predetermined optical effective area can be set to a desired shape according to the optical article, such as a rectangular shape or a circular shape, regardless of the outer shape of the glass substrate 2.

  The UV curable resin inherently tends to retain stress due to shrinkage when cured in a short period of time, and it is desirable to cure it after taking a certain amount of time. However, the curing time in this embodiment is applied to the coating layer portion to be cured. The time is set to a short time of about 0.2 to 0.5 seconds so that the shrinkage stress remains. Thereby, it acts as one factor which keeps balance with the tensile stress of the film | membrane of the high refractive index material layer H formed on the resin layer 3 later.

  When the coating layer 3a is irradiated with the ultraviolet ray UR, as shown in FIG. 2C, the region 3b which is cured by being irradiated with the ultraviolet ray UR, and the liquid region where the coating state of the ultraviolet curable resin is maintained (uncured) Region) 3c. The region 3 b where the ultraviolet curable resin is cured has a function as a side wall that prevents the ultraviolet curable resin in the liquid region 3 c from flowing out in the outer peripheral direction of the glass substrate 2. And the glass substrate 2 by which the ultraviolet-ray UR was irradiated to the coating layer 3a transfers to a laser irradiation process.

In the laser irradiation step, the liquid region 3c of the coating layer 3a is irradiated with a femtosecond laser pulse beam (hereinafter may be referred to as a beam) LB from the laser irradiation apparatus.
Prior to the description of the laser irradiation process, the laser irradiation apparatus 10 will be described with reference to FIG.

  The laser irradiation apparatus 10 includes a femtosecond laser oscillator 11 that emits a femtosecond laser pulse beam LB, a beam expander 12 that adjusts the beam diameter of the beam LB emitted from the femtosecond laser oscillator 11, and the beam intensity of the beam LB. An intensity adjuster 13 for adjusting, a mirror 14 for adjusting the traveling direction of the beam LB, a condenser lens 15, a moving stage 16, a stage controller 17 for controlling movement of the moving stage 16, and a computer 18 for controlling the stage controller 17 are provided. Yes.

The condensing lens 15 condenses the beam LB emitted from the femtosecond laser oscillator 11 on the surface of the liquid region 3c (see FIG. 2) of the coating layer 3a.
The moving stage 16 is controlled by the stage controller 17 and is configured to be arbitrarily movable in the X-axis direction, the Y-axis direction, and the Z-axis direction of the orthogonal coordinate system of the moving stage 16. The condensing position of the beam LB is relatively moved in the direction along the surface of the glass substrate 2. On the moving stage 16, the glass substrate 2 irradiated with the ultraviolet ray UR is placed.

  In this embodiment, the irradiation direction (mirror 14) of the beam LB is positioned and fixed in advance. Therefore, the glass substrate 2 placed on the moving stage 16 is moved to the surface of the liquid region 3c of the coating layer 3a by arbitrarily moving the moving stage 16 in the X-axis direction, the Y-axis direction and the Z-axis direction. The condensing position of the focused beam LB can be arbitrarily scanned.

As shown in FIG. 2D, using the laser irradiation apparatus 10 configured as described above, the surface portion of the liquid region 3c of the coating layer 3a, that is, the lowermost layer portion of the dielectric multilayer film 4 described later ( Irradiation with the femtosecond laser pulse beam LB is performed on a portion in contact with the TiO ₂ film H1) of the high refractive index material.
The femtosecond laser pulse beam LB emitted from the femtosecond laser oscillator 11 is set, for example, to a wavelength of 800 nm, a pulse width of 100 fs (femtosecond), a repetition frequency of 220 KHz, and an average output of 200 mW.

  The beam LB emitted from the femtosecond laser oscillator 11 enters the condenser lens 15 via the beam expander 12, the intensity adjuster 13, and the mirror 14. The beam LB incident on the condensing lens 15 is condensed by the condensing lens 15 onto the surface portion of the liquid region 3c of the coating layer 3a formed on the glass substrate 2 placed on the moving stage 16. Is done. The focused spot diameter of the beam LB is adjusted to about 25 μm on the surface of the liquid region 3c.

Then, when the moving stage 16 is moved in the X-axis direction and the Y-axis direction under the control of the stage controller 17, the position of the condensing spot of the beam LB condensed by the condensing lens 15 becomes the position of the glass substrate 2. Scanning that moves relative to the direction along the surface is performed. The scanning of the focused spot is performed on the surface of the liquid region 3c at a constant speed of about 1 mm / second.
When the focused spot is scanned over the entire surface of the liquid region 3c at a predetermined interval, only the surface portion of the liquid region 3c is cured, and as shown in FIG. The resin layer 3 is formed by being surrounded by the surface of the glass substrate 2, the region 3b in which the ultraviolet curable resin is cured in the ultraviolet irradiation process, and the region 3d cured by the irradiation with the femtosecond laser pulse beam LB. The

The femtosecond laser pulse beam LB is irradiated only in a minute space having a high photon density at the condensing point by irradiating a photopolymerizable resin (ultraviolet curable resin) with near infrared light of about 800 nm to 1200 nm. An optical process occurs, and only the surface portion of the liquid region 3c is cured by the photopolymerization action, so that a cured region 3d can be formed.
By using the femtosecond laser pulse beam LB, an unnecessary thermal reaction that occurs when a normal laser is used does not occur, so that internal stress does not occur in the resin itself. Further, by lowering the scanning speed of the focused spot, the refractive index of the cured ultraviolet curable resin can be increased, and the region 3d where the surface portion has been cured can be formed more accurately and thinner.

In the glass substrate 2 on which the resin layer 3 is formed, the dielectric multilayer film 4 is formed on the surface of the resin layer 3.
The dielectric multilayer film 4 is formed by attaching the glass substrate 2 on which the resin layer 3 is formed to a susceptor for film formation and placing it in a vacuum deposition chamber, and using a vacuum deposition method, a high refractive index layer H of TiO _2. And SiO ₂ low refractive index layers L are alternately formed in multiple layers (see FIG. 1).

In FIG. 1, the dielectric multilayer film 4 is a film in which the high refractive index material layer H is TiO ₂ (refractive index: 2.40) and the low refractive index material layer L is SiO ₂ (refractive index: 1.46). A film is formed of the material.
The dielectric multilayer film 4, as a first layer, are laminated TiO ₂ film H1 of the high refractive index material, the upper surface of the TiO ₂ film H1 of stacked high refractive index material, SiO ₂ film L1 of the low-refractive-index material Are stacked. Hereinafter, a TiO ₂ film of a high refractive index material and a SiO ₂ film of a low refractive index material are sequentially laminated alternately on the upper surface of the SiO ₂ film L1 of a low refractive index material, and the uppermost film layer is made of SiO of a low refractive index material. _Two films L30 are laminated to form a total of 60 dielectric layers, 30 high-refractive index material layers and 30 low-refractive index material layers.

Details of the film configuration of the dielectric multilayer film 4 will be described.
In the description of the film thickness configuration described below, the film thickness of the high refractive index material layer H is expressed as 1H for the value of the optical film thickness nd = 1 / 4λ, and the low refractive index material layer L is similarly expressed as 1L. . Further, the notation of S represented by (xH, yL) ^S represents that the configuration in parentheses is repeated periodically by the number of repetitions called the number of stacks. The design wavelength λ is 550 nm.

The thickness of the dielectric multilayer film 4 is such that the first layer of TiO ₂ film (high refractive index material layer) H1 is 0.60H on the upper surface of the resin layer 3, and the second layer has a low refractive index. The material SiO ₂ film (low refractive index material layer) L1 is 0.20L, and subsequently 1.05H, 0.37L, (0.68H, 0.53L) ⁴ , 0.69H, 0.42L,. 59H, 1.92L, (1.38H, 1.38L) ⁶ , 1.48H, 1.52L, 1.65H, 1.71L, 1.54H, 1.59L, 1.42H, 1.58L, 1 .51H, 1.72L, 1.84H, 1.80L, 1.67H, 1.77L, (1.87H, 1.87L) ⁷ , 1.89H, 1.90L, 1.90H, and so on A 0.96 L low refractive index material SiO ₂ film L30 is formed, and a total of 60 layers are formed.
The dielectric multilayer film 4 is formed, and the optical multilayer film filter 1 is completed.

Then, the completed optical multilayer filter 1 is taken out from the vacuum deposition chamber and naturally cooled.
Originally, the optical multilayer filter 1 (glass substrate 2) in which the high refractive index material layer H and the low refractive index material layer L are alternately formed to form a multilayer is composed of a SiO ₂ film of a low refractive index material. Due to the strong compressive stress and the weak tensile stress of the TiO ₂ film of the high refractive index material, warping occurs so that the formed multilayer surface becomes convex. However, the optical multilayer filter 1 is naturally cooled and gently cooled by the liquid region (region of uncured ultraviolet curable resin) 3c of the resin layer 3 formed on the surface of the glass substrate 2. The film stress of the high refractive index layer H1 (internal stress of the entire multilayer film) spreads in the liquid region 3c, so that the film stress is absorbed in the liquid region 3c and the optical multilayer filter 1 (glass substrate 2). It is possible to prevent the occurrence of warpage.

  Thus, by preventing the warp of the optical multilayer filter 1, it is possible to prevent the dielectric multilayer film 4 from peeling or cracking. Further, by preventing the occurrence of warping, the bonding accuracy is improved in the case of an optical article in which two or more glass substrates including at least one optical multilayer filter 1 are used, and high performance is achieved. Optical characteristics can be obtained. In particular, in the case of an optical article that is used by sandwiching a substrate such as a resin that is easily deformed between glass substrates, it is possible to further suppress deformation due to warpage.

  In addition, the optical multilayer filter 1 can easily obtain an optical low-pass filter in which the optical multilayer film filter having the UV-IR cut filter function is integrally formed, for example, when the glass substrate 2 is made of transparent crystal. Can do.

FIG. 4 is a schematic diagram for explaining the structure of the optical low-pass filter, the optical axis, and the traveling direction of the light beam. FIG. 4 is an exploded perspective view showing each layer constituting the optical low-pass filter.
The optical low-pass filter 100 includes two quartz plates 20 and 30 having birefringence and a quarter-wave plate 40 made of quartz, and the quarter-wave plate 40 is interposed between the two quartz plates 20 and 30. It is an example of the 45-degree separation type of the inserted three-layer structure. The quartz plate 20, the quarter-wave plate 40, and the quartz plate 30 constituting these three-layer structures are bonded together so that bubbles are not generated by an optical adhesive or the like.

  The quartz plate 20 is an optical multilayer film filter made of transparent quartz having birefringence, and is disposed on the light incident side. As described above, the resin layer 3 and the dielectric multilayer film 4 are formed in this order from the surface on the surface on the light incident side of the quartz plate 20 (not shown, see FIGS. 1 and 2).

  The quartz plate 20 has an optical axis in a direction (direction indicated by an arrow A1) that forms an azimuth angle of about 45 degrees with the z axis on a plane (xz plane) that is orthogonal to the light incident plane and parallel to the plane of the drawing. (Optical main axis). The light beam L10 incident on the crystal plate 20 is separated into two light beams L11 and L12 orthogonal to each other by the birefringence of the crystal plate 20. These light rays L11 and L12 are converted into linearly polarized light and emitted to the quarter-wave plate 40, respectively.

  The quarter-wave plate 40 has an optical axis in a direction (direction indicated by an arrow A2) that forms an azimuth angle of approximately 45 degrees with the x-axis on the light incident surface (xy plane). As a result, the light rays L11 and L12 incident on the quarter-wave plate 40 have their polarization states converted from linearly polarized light to circularly polarized light, respectively, and are emitted to the quartz plate 30 as two light rays L13 and L14.

  The crystal plate 30 disposed on the light emitting side has a direction (indicated by an arrow A3) that forms an azimuth angle of about 45 degrees with the y axis on a plane (yz plane) that is orthogonal to the light incident surface and orthogonal to the paper surface. Direction). The circularly polarized light beam L13 incident on the crystal plate 30 is separated into two light beams L15 and L16 that are orthogonal to each other in the horizontal direction and the vertical direction with respect to the incident surface. Similarly, the light beam L14 incident on the quartz plate 30 is separated into two light beams L17 and L18 that are orthogonal to each other in the horizontal direction and the vertical direction with respect to the incident surface. These light rays L15, L16, L17, and L18 are emitted with their polarization states converted into linearly polarized light, respectively.

  The optical low-pass filter 100 configured as described above can obtain an optical low-pass filter integrally configured with a UV-IR cut filter function. In particular, the optical low-pass filter 100 with less warpage and optical distortion can be obtained in a configuration in which the constituent quartz plates are bonded to form an integral structure.

The optical low-pass filter 100 in which the UV-IR cut filter function is integrally configured as described above can be used for, for example, a digital still camera. In addition, the optical low-pass filter 100 can be disposed as a dust-proof glass function, and a digital still camera with good optical characteristics and a good bonding system can be obtained.
The optical low-pass filter 100 can be used as an electronic device other than a digital still camera, for example, in an imaging unit such as a camera-equipped mobile phone or a camera-equipped personal computer (personal computer).

  As described above, according to the optical multilayer filter 1 of the present embodiment, the resin layer 3 is formed by the liquid region (region of uncured ultraviolet curable resin) 3c of the resin layer 3 formed on the surface of the glass substrate 2. The film stress (internal stress) due to the dielectric multilayer film 4 formed thereon spreads in the liquid region 3c, so that the film stress is absorbed in the liquid region 3c, and the optical multilayer filter 1 (glass substrate 2). It is possible to prevent the occurrence of warpage. By preventing the occurrence of warping, an optical multilayer film filter having high performance optical characteristics can be obtained while preventing the dielectric multilayer film 4 from peeling or cracking.

  Moreover, according to the manufacturing method of the optical multilayer filter of this embodiment, while the optical multilayer filter 1 which prevented generation | occurrence | production of the curvature of the glass substrate 2 is obtained, the formation process of the resin layer 3 is performed, for example in the glass substrate 2 It can be separated from the dielectric multilayer film forming process that requires a long film formation time by adding to the manufacturing process, etc., and efficient manufacturing can be performed without increasing the manufacturing cost due to film formation failure etc. Can do.

In the above embodiment, the optical multilayer filter 1 has been described as applied to a UV-IR cut filter. However, an optical multilayer such as a high reflection film, an IR cut filter, an antireflection film, and a half mirror is used. It can be applied to a membrane filter.
Moreover, although the optical multilayer filter 1 demonstrated the case where white plate glass was used for the glass substrate 2 as a board | substrate which permeate | transmits light, it is not limited to this, Crystal, BK7, sapphire glass, borosilicate glass, blue A transparent substrate such as plate glass, SF3, SF7, or generally available optical glass can be used.

Further, the case where TiO ₂ is used as the film forming material of the high refractive index material layer H has been described, but Ta ₂ O ₅ and Nb ₂ O ₅ can be applied. On the other hand, although the case where SiO ₂ is used as the film forming material of the low refractive index material layer L has been described, MgF ₂ can be used.
In addition, the dielectric multilayer film 4 is formed by using the vacuum vapor deposition method, but an ion assist vapor deposition method, an ion plating method, a sputtering method, or the like can be used. Furthermore, although the application of the ultraviolet curable resin for forming the resin layer 3 has been described in the case of using the spin coating method, it may be in the case of using a roll coating method.

  The optical multilayer filter 1 has been described in the case of manufacturing one optical multilayer filter 1 on the glass substrate 2 using a rectangular glass substrate 2 having a plane of about 50 mm. A large number of optical multilayer filters can be manufactured at once using the glass substrate. In this case, the resin layer 3 and the dielectric multilayer film 4 are formed, and the cooled glass substrate is cut using a laser cutter, a dicing cutter or the like, thereby completing many optical multilayer filters at once. can do.

  Moreover, although the case where the ultraviolet ray UR produced | generated from the high pressure mercury lamp of the ultraviolet irradiation device was used as an active energy ray in an active energy ray irradiation process was demonstrated, in addition to ultraviolet rays, activity of X rays, γ rays, electron beams, etc. Energy rays can be used. Moreover, a chemical lamp, a xenon lamp, a metal halide lamp, or the like can be used as the ultraviolet ray source.

The cross-sectional schematic diagram for demonstrating the structure of the optical multilayer film filter of this invention. It is a cross-sectional schematic diagram of the glass substrate which shows the aspect of the formation process of a resin layer, (a) is the glass substrate after an application | coating process, (b) is the glass substrate in an ultraviolet irradiation process, (c) is the glass after an ultraviolet irradiation process. A substrate, (d) shows a glass substrate in the laser irradiation step, and (e) shows a glass substrate after the resin layer is formed. The schematic block diagram of a laser irradiation apparatus. The schematic diagram explaining the structure of the optical low-pass filter using the optical multilayer film filter of this invention, and the advancing direction of an optical axis and a light ray.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical multilayer filter, 2 ... Glass substrate as a board | substrate, 3 ... Resin layer, 3a ... Application layer, 3b ... Area hardened by irradiating with ultraviolet rays, 3c ... Liquid area, 3d ... Femtosecond laser pulse beam Irradiated and hardened region, 4 ... Dielectric multilayer film, 5 ... Mask, 5a ... Opening, 10 ... Laser irradiation device, 11 ... Femtosecond laser oscillator, 15 ... Condensing lens, 16 ... Moving stage, 20, 30 ... Quartz plate, 40 ... 1/4 wavelength plate, 100 ... Optical low-pass filter, H ... High refractive index material layer, L ... Low refractive index material layer, LB ... Femtosecond laser pulse beam, UR ... Ultraviolet.

Claims (4)

In an optical multilayer filter having a dielectric multilayer film in which at least two kinds of films having different refractive indexes are alternately laminated on a substrate,
An optical multilayer filter, wherein a resin layer that absorbs internal stress of the dielectric multilayer film is formed between the substrate and the dielectric multilayer film. The optical multilayer filter according to claim 1, wherein
The resin layer is made of a photopolymerizable resin,
A cured region of the photopolymerizable resin formed along the peripheral edge of the surface of the substrate by irradiating active energy rays;
A liquid region of the photopolymerizable resin;
Irradiating a femtosecond laser pulse beam, a region where a portion in contact with the lowermost layer portion of the dielectric multilayer film is cured,
An optical multilayer filter comprising: The optical multilayer filter according to claim 2,
The liquid region of the photopolymerizable resin is
The substrate;
The cured region of the photopolymerizable resin irradiated with the active energy ray,
A region where the portion in contact with the lowermost layer portion of the dielectric multilayer film is cured;
An optical multilayer filter characterized by being held by A method of manufacturing an optical multilayer filter having a dielectric multilayer film in which at least two kinds of films having different refractive indexes are alternately laminated on a substrate,
On the surface of one side of the substrate,
A coating step of forming a coating layer made of a photopolymerizable resin;
An active energy ray irradiating step of forming a region cured by irradiating active energy rays to the coating layer along the peripheral edge of the substrate and a liquid region of the photopolymerizable resin;
A laser irradiation step of irradiating the liquid region with a femtosecond laser pulse beam to cure a portion in contact with the lowermost layer portion of the dielectric multilayer film;
A resin layer is formed,
A method for producing an optical multilayer filter, wherein the dielectric multilayer film is formed on the resin layer.

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