JP2006036560A - Glass member with optical multilayer film and optical element using the glass member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass member with an optical multilayer film without peeling when the optical multilayer film is formed on a fluorophosphate glass. <P>SOLUTION: The glass member with an optical multilayer film is formed by forming an optical multilayer film (e.g. an antireflection film 3, an IR cut film 4, etc.) on a fluorophosphate glass substrate 1, where an adhesiveness reinforcing film 2 which contains fluorine (F) and improves the adhesiveness of the optical multilayer to the fluorophosphate glass substrate is formed between the fluorophosphate glass substrate 1 and the optical multilayer film (e.g. an antireflection film 3, an IR cut film 4, etc.). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color sensitivity correction filter for a solid-state image pickup device such as a CCD or CMOS mounted in a digital camera or a video camera, a cover glass used when packaging a solid-state image pickup device such as a CCD or CMOS, a low-pass filter, The present invention relates to a heat ray filter, a glass member with an optical multilayer film used for them, and an optical element using the glass member.

The spectral sensitivity of solid-state imaging devices such as CCDs and CMOSs mounted on digital cameras and video cameras ranges from the visible range to the near infrared range near 1100 nm. Therefore, an image approximated to human visibility is obtained using a filter that absorbs the near infrared region. As a filter glass used for this purpose, a glass in which CuO is added to a phosphate glass has been used. However, a phosphate glass has poor weather resistance, and if it is exposed to high temperature and high humidity for a long time, the glass surface may become rough or cloudy. There was a disadvantage that it occurred. Therefore, near-infrared light absorbing filter glass based on a fluorophosphate glass containing a fluorine component and excellent in weather resistance has been developed and is commercially available.
As this type of glass, for example, a near-infrared light absorbing filter glass in which CuO is added to a fluorophosphate glass is disclosed (Patent Document 1).
JP-A-2-204342

In addition to the near-infrared light absorption filter glass described above, the optical elements mounted on digital cameras and video cameras exceeded the resolution limit of the CCD and the anti-reflection function that prevents reflection of light in the visible wavelength range. A low-pass filter or the like for removing the spatial frequency component is required, a substrate with an antireflection film or a low-pass filter is required, and these members are bonded together by an adhesive or the like.
By the way, in recent years, with the miniaturization of digital cameras and video cameras, the optical system of the camera is also required to save space, but the conventional optical elements are each formed as a single member, a near infrared absorption filter glass, Since each member of the substrate with the antireflection film and the low-pass filter were joined, it was not possible to save space.
In addition, a technique for forming an optical multilayer film on a near infrared light absorbing filter glass made of fluorophosphate glass has been proposed. The film peeling of the optical multilayer film is a problem.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a glass member with an optical multilayer film in which film peeling does not occur even when an optical multilayer film is formed on a fluorophosphate glass, and the glass member. It is providing the optical element using this.

(Configuration 1) A glass member with an optical multilayer film in which an optical multilayer film is formed on a fluorophosphate glass substrate,
An adhesion reinforcing film containing fluorine (F) and improving the adhesion of the optical multilayer film to the fluorophosphate glass substrate is formed between the fluorophosphate glass substrate and the optical multilayer film. A glass member with an optical multilayer film.
(Configuration 2) The adhesion reinforcing film is made of magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), lanthanum fluoride (LaF ₃ ), neodymium fluoride (NdF ₃ ), cerium fluoride (CeF ₃ ). The glass member with an optical multilayer film according to Configuration 1, which is a material selected from any one of the above.
(Structure 3) The film thickness of the adhesion enhancing film is not less than a film thickness that can cover the main surface of the glass substrate and does not affect the optical characteristics of the optical multilayer film. The glass member with an optical multilayer film according to Configuration 1 or 2, wherein:
(Configuration 4) The glass with an optical multilayer film according to any one of configurations 1 to 3, wherein the fluorophosphate glass substrate is made of a material containing 20 to 40% of P ^{5+ in} terms of cation%. Element.
(Configuration 5) An optical element formed by cutting the glass member with an optical multilayer film according to any one of Configurations 1 to 4 into a predetermined size.

  ADVANTAGE OF THE INVENTION According to this invention, even if an optical multilayer film is formed in a fluorophosphate glass, the glass member with an optical multilayer film which does not generate | occur | produce film | membrane, and the optical element (for example, optical filter etc.) using this glass member can be provided.

The present invention relates to a glass member with an optical multilayer film in which an optical multilayer film is formed on a fluorophosphate glass member such as a fluorophosphate glass substrate, the fluorophosphate glass substrate (fluorophosphate glass member) and the above-mentioned An adhesion reinforcing film containing fluorine (F) and improving the adhesion of the optical multilayer film to the fluorophosphate glass substrate (fluorophosphate glass member) is formed between the optical multilayer film and the optical multilayer film. To do.
In the present invention, the fluorophosphate glass means a glass containing fluorine (F) among glasses containing phosphoric acid (phosphorus oxide) as a glass forming oxide. This fluorophosphate glass is sometimes referred to as fluorophosphate glass or fluorophosphate glass.

Examples of the optical multilayer film include optical multilayer films such as an antireflection film (AR film: Anti Reflection film) having an antireflection function, a dichroic filter having a wavelength selection function, and an infrared shielding film (IR cut film).
Specifically, in the case of an antireflection film, from the substrate side, a laminated film of Al ₂ O ₃ / ZrO ₂ / MgF _2, a laminated film of TiO ₂ / SiO ₂ ..., A laminated film of Ta ₂ O ₅ / SiO ₂ . , Si—Sn—O / TiO ₂ / SiO ₂ laminated film, Si—Sn—O / Nb ₂ O ₅ / SiO ₂ laminated film, and the like.
In the case of the IR cut film, a laminated film of TiO ₂ / SiO ₂ ..., A laminated film of Ta ₂ O ₅ / SiO ₂ ... And a laminated film of ZrO ₂ / SiO ₂ .
Examples of the method for forming the optical multilayer film include a vacuum deposition method, a sputtering method, a CVD method, and an ion beam deposition method.
The optical multilayer film can be formed on one side or both sides of a fluorophosphate glass substrate.
Specifically, a fluorophosphate glass substrate / AR film, a fluorophosphate glass substrate / IR cut film, an AR film / fluorophosphate glass substrate / AR film, an AR film / fluorophosphate glass substrate / IR cut film, etc. It can be formed as follows.

As the adhesion reinforcing film, a material containing fluorine (F) is preferable. Specific examples include magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), lanthanum fluoride (LaF ₃ ), neodymium fluoride (NdF ₃ ), and cerium fluoride (CeF ₃ ). In particular, in order not to affect the optical properties of the optical multilayer film formed on the adhesion reinforcing film, a material having a refractive index as low as possible is preferable, and further, magnesium fluoride (MgF) is preferable because it can be easily formed. ₂ ) is preferred.
The film thickness of the adhesion strengthening film may be a film thickness that can enhance the adhesion, but is preferably a film thickness that can cover the main surface of the glass substrate (continuous film) or more. It is desirable that the thickness be less than that which does not affect the optical characteristics of the optical multilayer film to be formed. Specifically, the lower limit of the adhesion reinforcing film is preferably 10 nm or more (at least 10 nm). If the thickness is less than 10 nm, the film thickness controllability at the time of film formation deteriorates, and unevenness of the adhesion reinforcing film due to film thickness variations is likely to occur.
The glass member with an optical multilayer film in which the optical multilayer film is formed on the fluorophosphate glass substrate is treated with an aqueous solution. For example, it is a case where a cleaning process or a glass member is cut into a predetermined size. Even if these aqueous solutions are treated, if an adhesion enhancing film is interposed as in the present invention, the adhesion with the optical multilayer film is good and film peeling does not occur.

In the case where the function as a near-infrared light absorption filter (color correction filter) is regarded as important, the fluorophosphate glass substrate is expressed as cation% when the content of the cation component is expressed as cation%. It is preferably made of a fluorophosphate glass material containing 20 to 40% of P ⁵⁺ . P ⁵⁺ is a basic component of ^{fluorophosphate} glass and is an important component that brings about absorption in the near infrared region. If it is less than 20%, the color correction function deteriorates and becomes greenish, and it is not preferable, and if it exceeds 40%, weather resistance and devitrification resistance deteriorate, which is not preferable. More preferably, it is 25 to 35%.

An optical element such as an optical filter can be obtained by cutting the glass member with an optical multilayer film into a predetermined size.
An outline of a method for manufacturing an optical element such as an optical filter by cutting the glass member into a predetermined size will be described.
For example, about 50 glass substrates on which various optical thin films are formed on a fluorophosphate glass having a size of 90 mm × 90 mm and a thickness of 0.5 mm prepared by precision polishing are prepared, and these are UV curable resin (peeled with water). Laminated large blocks are laminated by being bonded to each other with an adhesive). Next, this laminated large block is cross-cut in the stacking direction vertically and horizontally (for example, 4.5 mm × 4.5 mm, 14 mm × 14 mm, 20 mm × 20 mm, cross-cut) to obtain a large number of stacked small blocks. Next, for each of the obtained laminated small blocks, in a state of the laminated small block, after chamfering all at once, the ultraviolet cured resin is swollen by immersing in water for a required time, and each piece is peeled off Then, after separating each substrate, cleaning is performed and 100% inspection is performed. Thereby, an optical element such as an optical filter cut to a predetermined size is obtained.

Applications of optical elements such as optical filters can be used in mobile phones, digital cameras, video cameras, and the like.
The size of an optical element such as an optical filter is generally about 4 to 7 mm × 4 to 7 mm for mobile phone use, and about 8 to 14 mm × 8 to 14 mm for small digital camera use.

Next, examples of the present invention will be described.
(Example 1) (Near-infrared light absorption filter with antireflection film)
Forming 18 nm thick magnesium fluoride (MgF ₂ ), which is an adhesion-strengthening film, on a plurality of fluorophosphate glasses 90 mm × 90 mm in size and 0.5 mm in thickness by precision polishing, respectively, by vacuum deposition After that, aluminum oxide (Al ₂ O ₃ ) (film thickness: 67 nm) / zirconium oxide (ZrO ₂ ) (film thickness: 130 nm) / magnesium fluoride (MgF ₂ ) (film thickness: 98 nm) are similarly applied from the substrate side by vacuum deposition. A plurality of glass substrates with antireflection films were obtained by sequentially forming an antireflection film formed by laminating. As shown in FIG. 1, this optical characteristic was good with a reflectance of 0.1% or less in a visible region of about 430 nm to about 640 nm. In addition, as shown in FIG. 1, compared with Comparative Example 1 in which no adhesion enhancing film is formed, although the adhesion enhancing film is interposed, the reflectance is slightly decreased and adverse effects such as an increase in reflectance are not caused. I knew it was n’t there.
The obtained glass substrates with antireflection films are laminated, cut into a size of 5 mm x 5 mm, and then subjected to ultrasonic cleaning to use a near infrared light absorption filter with an antireflection film (reflection) for use in mobile phones. 980 sheets of color correction filters with a protective film were obtained.
When all the obtained near-infrared light absorbing filters with antireflection films were inspected, the substrate was greatly warped, but no film peeling was confirmed. Adhesion strength test (adhesive tape specified in JISZ1522 having a width of 12 to 19 mm is attached to the antireflection film. Next, the adhesive tape is pulled strongly so as to be perpendicular to the film surface of the antireflection film. Even after the test method of peeling the adhesive tape instantly), no film peeling was confirmed.
Furthermore, even after the high temperature and high humidity durability test (conditions: temperature: 60 ° C. × humidity: 90% × time: 1000 hours), no film peeling was confirmed. Moreover, as confirmation of reproducibility, film peeling was not confirmed even when the same high-temperature and high-humidity durability test was performed 5 times using glass substrates with different deposition lots.

(Example 2) (Near-infrared absorption filter with IR cut film)
A magnesium fluoride (MgF ₂ ) film, which is an adhesion-strengthening film, is formed on a 90 mm × 90 mm, 0.5 mm thick fluorophosphate glass that has been precisely polished by vacuum deposition, and then vacuumed. An infrared shielding film (IR cut film) formed by laminating 13 layers of TiO ₂ / SiO ₂ as a lamination unit by a vapor deposition method was formed to obtain a glass substrate with an IR cut film. This IR cut film is an IR cut film having a half-value wavelength of 50% transmittance and 650 nm.
As shown in FIG. 2, this optical characteristic was such that light in the infrared region of about 700 nm to about 900 nm was blocked as much as possible (transmittance of about 0.1% or less). Further, as shown in FIG. 2, there is no substantial difference in transmittance characteristics as compared with Comparative Example 2 in which no adhesion enhancing film is formed (the transmittance curves of Example 2 and Comparative Example 2 are substantially different from each other). No effect was observed on the transmittance characteristics due to the presence of the adhesion enhancing film.
The obtained glass substrate with a near-infrared shielding film was cut into a size of 7.5 mm × 7.5 mm, and then subjected to ultrasonic cleaning, and a near-infrared light absorption filter with an IR-cut film (color correction filter with an IR-cut film) ) Was obtained.
When the obtained near-infrared light-absorbing filter with an IR cut film was inspected 100%, the substrate was greatly warped, but no film peeling was confirmed. Moreover, although the adhesion strength test and the high-temperature, high-humidity durability test were conducted in the same manner as in Example 1, no film peeling was confirmed. Moreover, as confirmation of reproducibility, film peeling was not confirmed even when the same high-temperature and high-humidity durability test was performed 5 times using glass substrates with different deposition lots.

(Comparative Examples 1 and 2)
A near-infrared light absorbing filter was produced in the same manner as in Examples 1 and 2 except that magnesium fluoride (MgF ₂ ), which is an adhesion enhancing film, was not formed in the above-described Examples.
Regarding the obtained near-infrared light absorbing filter, in the manufacturing process (cutting, ultrasonic cleaning step), 50 of 1000 sheets were peeled off from the optical multilayer film. Further, an adhesion strength test and a high temperature and high humidity durability test were conducted in the same manner as in Example 1 above, and many film peelings were confirmed.

Example 3 (Optical element having a structure of antireflection film / fluorophosphate glass substrate / IR cut film)
As shown in FIG. 3, on one surface of a fluorinated glass substrate 1 having a size of 90 mm × 90 mm and a thickness of 0.5 mm obtained by precision polishing, magnesium fluoride as an adhesion strengthening film 2 is formed by vacuum deposition. after the (MgF ₂₎ with a thickness of 18nm formed, aluminum oxide by vacuum deposition similarly _{(Al 2 O} 3) _(thickness 67 nm) / zirconium oxide _(ZrO 2) (film thickness 130 nm) / magnesium fluoride _(MgF 2) An antireflection film 3 was formed by sequentially laminating (film thickness 98 nm) from the substrate side. Further, the fluorine fluoride glass substrate 1 on which the antireflection film 3 is formed is formed on the other surface of the fluorophosphate glass substrate 1 (the surface opposite to the surface on which the antireflection film 3 is formed) by the vacuum deposition method. After forming magnesium oxide (MgF ₂ ) to a thickness of 18 nm, an IR cut film 4 is formed by laminating 13 layers of TiO ₂ / SiO ₂ in the same manner by vacuum deposition, and a fluorophosphate glass 50 glass substrates having an antireflection film formed on one surface of the substrate and an IR cut film formed on the other surface were obtained.
A laminate in which 50 glass substrates (antireflection film / adhesion-enhancement film / fluorophosphate glass substrate / adhesion-enhancement film / IR cut film) obtained were adhered and laminated together with an ultraviolet curable resin (adhesive that peels off with water). Large block. Next, this laminated large block is cross-cut (7.5 mm × 7.5 mm) vertically and horizontally in the laminating direction to obtain a large number of laminated small blocks. Next, for each of the obtained laminated small blocks, in a state of the laminated small block, after chamfering all at once, the ultraviolet cured resin is swollen by immersing in water for a required time, and each piece is peeled off After separating each substrate, ultrasonic cleaning was performed to obtain 5000 near-infrared light absorption filters (color correction filters) with an antireflection film and an IR cut film.
In addition, when the antireflection film and the IR cut film were respectively formed, warpage in which the warpage amount and the warpage direction were different occurred in the substrate, but film peeling was not confirmed at each time point, and the film was caused by warpage of the substrate. No peeling was confirmed.
When 100% inspection was performed on the near-infrared light absorbing filter with the antireflection film and IR cut film obtained above, the substrate was greatly warped, but no film peeling was observed on any surface. Moreover, although the adhesion strength test and the high-temperature, high-humidity durability test were conducted in the same manner as in Example 1 above, no film peeling was confirmed on any surface.

Example 4
In Example 3 described above, as a fluorophosphate glass substrate, a fluorophosphate glass substrate described in JP-A-2004-83290, which contains 20 to 40% of P5 ^{+ in} terms of cation% ( Specifically, it has each composition shown in FIG. 4, and has a thermal expansion coefficient of 150 to 180 × 10 ⁻⁷ / ° C. (0 to 300 ° C.), specifically, 150 × 10 ^−7. Except for using a glass substrate that is / 10 ° C, 160 × 10 ⁻⁷ / ° C., 165 × 10 ⁻⁷ / ° C., 170 × 10 ⁻⁷ / ° C., 180 × 10 ⁻⁷ / ° C. In the same manner as in No. 3, an antireflection film having an antireflection film / fluorophosphate glass substrate / IR cut film structure and a near infrared light absorption filter (color correction filter) with an IR cut film for each thermal expansion coefficient 5000 sheets were produced.
For each thermal expansion coefficient, when the antireflection film and the IR cut film were formed, the substrate was warped in a different amount and direction, but no film peeling was confirmed at each time point. The film peeling due to the warpage of the substrate was not confirmed.
When the antireflection film and the near-infrared light absorbing filter with an IR cut film obtained above were inspected, no film peeling was confirmed on any surface for each coefficient of thermal expansion. Further, the adhesion strength test and the high temperature and high humidity durability test were performed in the same manner as in Example 1 described above, but no film peeling was observed on any surface for each of the thermal expansion coefficients.
The fluorophosphate glass substrate used in this example includes a case where the thermal expansion coefficient is high (specifically, the case where the thermal expansion coefficient is 165 to 180 × 10 ⁻⁷ / ° C. (0 to 300 ° C.)). Nevertheless, it has been found that even when such a thermal expansion coefficient is high, film peeling does not occur at all. Thus, even when the thermal expansion coefficient is high, film peeling does not occur at all. Thus, it can be seen that the fluorophosphate glass substrate having the above composition is particularly excellent in adhesion with the adhesion reinforcing film of the present invention. This is because the glass composition of the fluorophosphate glass substrate having the composition used in this example and the factor based on the glass interface (factors affecting the bonding force between the substrate and the film, such as intermolecular forces, functional groups, etc.) It is thought that this is because it contributes to the enhancement of adhesion with the adhesion-strengthening film of the present invention.
In Examples 3 and 4 described above, except that each of the IR cut films 4 was formed by stacking 40 or 60 layers of TiO ₂ / SiO ₂ as a stack unit by vacuum deposition. In the same manner as in Example 3, a near-infrared light absorption filter (color correction filter) with an antireflection film and an IR cut film was prepared, and the same test was performed. As a result, the same as in Examples 3 and 4 above. As a result, it was confirmed that even when 40 or 60 optical multilayer films were formed, the optical multilayer film did not peel off.

(Examples 5 to 8)
The adhesion-strengthening films in Examples 1 and 2 are calcium fluoride (CaF ₂ ) (Example 5), lanthanum fluoride (LaF ₂ ) (Example 6), neodymium fluoride (NdF ₃ ) (Example 7). ), Cerium fluoride (CeF ₃ ) (Example 8), and a film for color correction was prepared in the same manner as in Examples 1 and 2 except that the film thickness was 18 nm. The optical multilayer film formed on the adhesion reinforcing film was prepared by appropriately adjusting the film thickness in consideration of the refractive index and film thickness of the adhesion reinforcing film material.
The adhesion strength test and the high-temperature and high-humidity durability test similar to those described above were performed, but no film peeling was confirmed in any of the tests, and good results were obtained.

  The glass member with an optical multilayer film of the present invention and the optical element using the glass member include a color sensitivity correction filter of a solid-state imaging device such as a CCD or CMOS mounted on a digital camera, a video camera, or the like, a CCD or CMOS, etc. It can be used for optical elements that require high durability, such as cover glasses, low-pass filters, heat ray filters, and other optical multilayer optical components used when packaging solid-state imaging elements.

It is a figure which shows the optical characteristic (wavelength-reflectance) of the near-infrared-light absorption filter with an antireflection film obtained in Example 1 and Comparative Example 1. It is a figure which shows the optical characteristic (wavelength-transmittance) of the near-infrared-light absorption filter with an IR cut film obtained in Example 2 and Comparative Example 2. It is a schematic diagram for demonstrating the structure of the near-infrared-light absorption filter with an antireflection film and IR cut film which were produced in Example 3. FIG. It is a figure which shows the composition and thermal expansion coefficient of a fluorophosphate glass substrate used in Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluorophosphate glass substrate 2 Adhesion reinforcement film 3 Antireflection film 4 IR cut film

Claims (5)

A glass member with an optical multilayer film in which an optical multilayer film is formed on a fluorophosphate glass substrate,
An adhesion reinforcing film containing fluorine (F) and improving the adhesion of the optical multilayer film to the fluorophosphate glass substrate is formed between the fluorophosphate glass substrate and the optical multilayer film. A glass member with an optical multilayer film. The adhesion reinforcing film is selected from any of magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), lanthanum fluoride (LaF ₃ ), neodymium fluoride (NdF ₃ ), and cerium fluoride (CeF ₃ ). The glass member with an optical multilayer film according to claim 1, wherein the glass member is a material to be manufactured. The adhesion reinforcing film has a film thickness that is not less than a film thickness that can cover the main surface of the glass substrate and that does not affect the optical characteristics of the optical multilayer film. The glass member with an optical multilayer film according to claim 1 or 2. 4. The glass member with an optical multilayer film according to claim 1, wherein the fluorophosphate glass substrate is made of a material containing 20 to 40% of P ^{5+ in} terms of cation%. 5. An optical element formed by cutting the glass member with an optical multilayer film according to any one of claims 1 to 4 into a predetermined size.

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