JP2010197595A - Near infrared ray cutting filter glass, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently seal a near infrared ray cutting filter glass to a solid-state image pickup element package by using an ultraviolet ray curing type adhesive. <P>SOLUTION: The near infrared ray cutting filter glass has a plate shape, is made of CuO-containing fluoro-phosphate glass or CuO-containing phosphate glass and has an optical effective section for transmitting light and a peripheral section which adjoins an outer periphery of the optical effective section. Ultraviolet ray transmittance of the peripheral section is higher than that of the optical effective section. When the near infrared ray cutting filter glass is sealed to the solid-state image pickup element package by using the ultraviolet ray curing type adhesive, the near infrared ray cutting filter glass can be rapidly applied to the package and thereby a solid-state image pickup element device can be efficiently assembled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a near-infrared cut filter glass used for correcting the visibility of a solid-state imaging device and a method for manufacturing the same.

  A solid-state imaging device such as a CCD or CMOS used for a digital still camera or the like has a spectral sensitivity ranging from the near ultraviolet region to the near infrared region of around 1200 nm, and therefore, good color reproducibility cannot be obtained as it is. Therefore, the near-infrared cut filter glass to which a specific substance that absorbs infrared rays is added is used to correct the incident light to the image sensor to approximate human visibility. As this near-infrared cut filter glass, optical glass in which CuO is added to fluorophosphate glass or phosphate glass that selectively absorbs wavelengths in the near-infrared region has been developed and used.

The near-infrared cut filter glass contains CuO in the glass for the purpose of absorbing near-infrared rays, but by incorporating CuO in the glass, not only near-infrared rays but also ultraviolet rays are absorbed. The transmittance curve of such near-infrared cut filter glass containing CuO does not transmit wavelengths below 300 nm, the transmittance increases sharply in the wavelength range of 300 nm to 400 nm, and gradually decreases from 600 nm to 700 nm. It is a curved line. Since the solid-state imaging device has sensitivity in the near-ultraviolet region as described above, in recent years, due to the chromatic aberration of the lens system due to the increase in the number of pixels of the imaging device, a purple outline blur is added to the captured image. Near-infrared cut filter glass has been developed that has improved the ability to absorb ultraviolet rays in order to eliminate blurring caused by ultraviolet rays, that is, the cut wavelength on the ultraviolet side has been shifted to the longer wavelength side (patented) Reference 1).
On the other hand, video cameras and digital still cameras using solid-state image sensors are being reduced in size and cost, and near-infrared cut filter glass is directly sealed in the openings of the solid-state image sensor package in order to reduce the number of parts. It has been proposed to stop use (Patent Document 2).

JP 2008-1543 A Japanese Patent Laid-Open No. 7-281021

The window glass for a solid-state image sensor package is hermetically sealed with an adhesive at an opening of a package made of ceramics or resin in which the solid-state image sensor is housed. However, in recent years, UV curing has been performed for the purpose of shortening the adhesive curing time. Mold adhesives are being used.
There are various types of ultraviolet curable adhesives, and as an example, they are cured by ultraviolet rays having a wavelength of 250 nm to 350 nm. However, when the near-infrared cut filter glass is used as a window glass for a solid-state imaging device package and an ultraviolet curable adhesive is used for bonding to the package as described in Patent Document 2, most of the irradiated ultraviolet rays are absorbed by the glass. Thus, a new problem has been confirmed that it takes a long time to cure the adhesive.

  An object of the present invention is to provide a near-infrared cut filter glass that can be sealed using an ultraviolet curable adhesive even when the near-infrared cut filter glass is used as a window glass for a solid-state imaging device package.

  The near-infrared cut filter glass according to the present invention is a plate-like near-infrared cut filter glass made of a fluorophosphate-based glass containing CuO or a phosphate-based glass containing CuO, and is optically effective for transmitting light. And a peripheral portion adjacent to the outer periphery of the optically effective portion, and the ultraviolet transmittance of the peripheral portion is higher than the ultraviolet transmittance of the optically effective portion.

  In the present invention, as a method of making the ultraviolet transmittance of the peripheral portion higher than the ultraviolet transmittance of the optically effective portion, the peripheral portion surrounds the outer periphery of the optically effective portion in a frame shape, and the thickness of the peripheral portion is There is a method in which the thickness of the optically effective portion is reduced compared to the thickness of the optically effective portion, and a difference in the amount of ultraviolet absorption due to the thickness difference is utilized.

The method for producing a near-infrared cut filter in the case of using the difference in the amount of ultraviolet absorption due to the difference in plate thickness has the following steps.
(1) melting a fluorophosphate glass containing CuO or a phosphate glass containing CuO to obtain a plate-like glass;
(2) a step of optically polishing both surfaces of the plate-like glass;
(3) a step of forming lattice-like grooves on one side of the plate-like glass;
(4) A step of cutting and separating the plate-like glass along the center line of the formed groove.
As another method, there is a method in which the glass composition of the peripheral portion has a CuO content less than the glass composition of the optically effective portion or a difference in concentration of CuO that is an ultraviolet absorbing component due to not containing CuO. is there.

The method for producing a near-infrared cut filter in the case of using the concentration difference of the ultraviolet absorbing component has the following steps.
(1) Melting infrared absorbing glass containing CuO, creating a square columnar glass rod, and optically polishing the four outer surfaces;
(2) a step of melting and molding a glass having a CuO content less than that of the infrared absorbing glass or not containing CuO to form a glass plate, and optically polishing at least two adjacent surfaces;
(3) A step of creating a base material surrounding the four outer peripheral surfaces of the glass rod by bonding the polished surfaces of the glass plate to the polished surfaces of the square columnar glass rod,
(4) a step of heating and stretching the base material to a predetermined dimension;
(5) a step of cutting the stretched base material in a direction perpendicular to the stretching axis to form a flat glass;
(6) A step of optically polishing both surfaces of the flat glass.

The near-infrared cut filter glass of the present invention has a higher ultraviolet transmittance at the peripheral portion that becomes a sealing portion with respect to the package than the ultraviolet transmittance of the optically effective portion, so that the amount of ultraviolet light necessary for curing the adhesive can be secured. Then, it can be attached to the package using an ultraviolet curable adhesive, which makes it possible to efficiently assemble a solid-state imaging device.
Moreover, according to the manufacturing method of the near-infrared cut filter glass of this invention, a part with a high ultraviolet-ray transmittance can be formed in the peripheral part of this near-infrared cut filter glass with few man-hours.

It is a perspective view of Embodiment 1 of the near-infrared cut filter glass of this invention. It is a side view of Embodiment 1 of the near-infrared cut filter glass of this invention. It is a longitudinal cross-sectional view which shows an example of the solid-state image sensor device in which the near-infrared cut filter glass (Embodiment 1) of this invention was used. It is the flowchart which showed one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is the flowchart which showed other embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is explanatory drawing which shows the groove | channel formation process in one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a top view which shows the groove | channel formation state in one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a perspective view which shows the groove | channel formation state in one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is sectional drawing which shows an example of the solid-state image sensor device in which the near-infrared cut filter glass (Embodiment 1) of this invention was used. It is explanatory drawing which shows the cutting process in one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a side view of other embodiment of the near-infrared cut filter glass of this invention. It is explanatory drawing which shows the groove | channel formation process in other embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is explanatory drawing which shows the groove | channel formation process in further another embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a perspective view of Embodiment 2 of the near-infrared cut off filter of this invention. It is a longitudinal cross-sectional view of Embodiment 2 of the near-infrared cut filter glass of this invention. It is a longitudinal cross-sectional view which shows an example of the solid-state image sensor device in which the near-infrared cut filter glass (Embodiment 2) of this invention was used. It is the flowchart which showed other embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a perspective view which shows the glass rod material of the near-infrared cut filter glass of this invention. It is a perspective view which shows the glass plate material of the near-infrared cut filter glass of this invention. It is a perspective view which shows the base material before extending | stretching of the near-infrared cut filter glass of this invention. It is explanatory drawing which shows the cutting process in other embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is explanatory drawing which shows the outline of the extending | stretching process in one Embodiment of the manufacturing method of the near-infrared cut filter glass of this invention. It is a figure which shows the spectral transmission factor according to site | part of one Embodiment of the near-infrared cut filter glass of this invention. It is a figure which shows the spectral transmittance according to site | part of other embodiment of the near-infrared cut filter glass of this invention. It is a perspective view of Embodiment 3 of the near-infrared cut off filter of this invention. It is a longitudinal cross-sectional view which shows an example of the solid-state image sensor device in which the near-infrared cut filter glass (Embodiment 3) of this invention was used.

<Embodiment 1>
The first embodiment will be described.
FIG. 1 is a perspective view of Embodiment 1 of the near-infrared cut filter glass 1 of the present invention, and FIG. 2 is a side view of Embodiment 1 of the near-infrared cut filter glass 1 of the present invention. FIG. 3 is a longitudinal sectional view of a solid-state image sensor device 100 in which the near-infrared cut filter glass 1 of the present invention is sealed in the opening of the package 9 of the solid-state image sensor 8.

The near-infrared cut filter glass 1 of the first embodiment (hereinafter sometimes abbreviated as filter glass 1) has a rectangular plate-like appearance as shown in FIGS. The first light-transmitting surface 5 serving as the outer surface and the second light-transmitting surface 6 that faces the solid-state imaging device 8 when sealed in the package 9, and the side surface 4 that constitutes the outer peripheral edge of the filter glass 1. A peripheral edge 3 serving as a sealing portion with the package 9 is formed in a frame shape on the outer periphery of the second light transmitting surface 6, and a wall is formed at the boundary between the peripheral edge 3 and the second light transmitting surface 6 that is an optically effective portion. A step 2 due to a thickness difference is formed.
The optically effective portion refers to a range in which light incident on the solid-state imaging element 8 is transmitted through the filter glass 1 and is inside the sealing portion between the filter glass 1 and the package 9.
The peripheral portion includes a range (sealing portion) that is adjacent to the outer periphery of the optically effective portion and adheres to the adhesive 7 provided between the filter glass 1 and the opening of the package 9. It is formed to be thinner (hereinafter, the peripheral portion 3 of the first embodiment is referred to as the thin portion 3).

As shown in FIG. 3, the filter glass 1 of the present invention incorporates a solid-state imaging device 8 (CCD or CMOS) in a package 9 made of alumina ceramic or resin and hermetically seals the opening. Accordingly, it is intended to protect the solid-state image sensor 8 and prevent dust and dust from adhering to the light receiving surface of the solid-state image sensor 8.
For bonding the filter glass 1 and the package 9, a thermosetting adhesive or a low-melting glass has been conventionally used. In recent years, an ultraviolet curable adhesive is used for the purpose of shortening the curing time of the adhesive. It is like that.
The ultraviolet curable adhesive 7 is an adhesive having a property of being cured in a short time when irradiated with ultraviolet rays (for example, a wavelength in the range of 250 nm to 350 nm).
As an assembling method of the filter glass 1 and the package 9, an ultraviolet curable adhesive 7 is applied to the thin portion 3 of the filter glass 1 or the upper surface of the opening of the package 1. Then, after the filter glass 1 is installed at a predetermined position of the package 9, an ultraviolet lamp is irradiated for a predetermined time, and the adhesive 7 is cured to hermetically seal.

  Here, there is a correlation between the curing rate of the ultraviolet curable adhesive 7 and the integrated light quantity of ultraviolet rays reaching the adhesive 7. Therefore, if sufficient ultraviolet rays do not reach the adhesive 7 provided on the back surface of the thin portion 3 of the filter glass 1, it takes a long time to cure the adhesive 7, and the efficiency of the assembly process of the filter glass 1 and the package 9 is increased. Becomes very bad.

  The filter glass 1 of the present invention has a near-infrared cut function for the purpose of correcting the visibility of the solid-state imaging device 8. Although details of the glass composition will be described later, CuO is contained in the fluorophosphate glass or phosphate glass in order to give the glass a function of cutting near infrared rays. This CuO is a component for cutting near-infrared rays. However, even when contained in a very small amount, the transmittance in the near-ultraviolet region sharply decreases and has a function of cutting ultraviolet rays near 300 nm almost completely. Therefore, in the filter glass 1 of the first embodiment, it is necessary in the optically effective portion by increasing the ultraviolet transmittance of the thin portion 3 that does not affect the light reception of the solid-state imaging device 8 compared to the ultraviolet transmittance of the optically effective portion. While maintaining the transmission characteristics, the amount of ultraviolet light transmitted through the thin wall portion 3 where the adhesive 7 is provided is increased, and sufficient ultraviolet light reaches the adhesive 7 provided in the thin wall portion 3 of the filter glass 1. Therefore, the filter glass 1 and the package 9 can be efficiently assembled.

As a method for increasing the ultraviolet transmittance of the thin portion 3 of the filter glass 1 compared to the ultraviolet transmittance of the optically effective portion, a frame formed on at least one surface of the thin portion 3 so as to be thinner than the plate thickness of the optically effective portion. There is a method of providing the thin portion 3 through the stepped portion 2. As a method for forming the thin portion 3, there is a method of mechanically grinding with a grinding wheel such as a diamond wheel.
When forming the thin-walled portion 3 by grinding, it is possible to individually grind the outer edge of the rectangular plate glass processed to the final product size, but because it is individual processing and productivity is low, the following It is preferable to set it as a process. That is,
(1) A step of obtaining a plate-like glass 10 by melting a fluorophosphate-based glass containing CuO or a phosphate-based glass containing CuO,
(2) a step of optically polishing both surfaces of the plate-like glass 10;
(3) a step of forming lattice-like grooves 11 on one side of the plate-like glass 10;
(4) A step of cutting and separating the plate-like glass 10 along the center line of the formed groove 11.

  Some products have an optical thin film such as an infrared cut film or an ultraviolet cut film formed on the near infrared cut filter glass 1 to adjust the spectral transmittance characteristics. Needless to say, the ultraviolet cut film, the infrared cut film reflects the light on the short wavelength side from the near ultraviolet region of 300 to 400 nm due to its characteristics. Therefore, the filter glass 1 on which such an optical thin film is formed is formed into an ultraviolet curable type. When the adhesive 7 is used to adhere to the package 9, the optical thin film cuts off the ultraviolet rays and hinders the curing reaction of the adhesive 7.

  In the case of the window glass for a solid-state image pickup device package in which an optical thin film having an ultraviolet cut function such as an infrared cut film or an ultraviolet cut film is formed so as to be superimposed on the near infrared cut filter glass 1 in this way, next to the step (2) Then, an optical thin film having an ultraviolet cut function is formed on one surface of the plate-like glass 10, and then in the step (3), a lattice-like groove 11 is formed on the surface on the side where the optical thin film is formed. Is preferred. With such a process, since the optical thin film having an ultraviolet cut function formed on one surface of the plate-like glass 10 is removed together with the glass as the grooves 11 are formed, the grooves 11, that is, the frame shape in the final product. No optical thin film having an ultraviolet cut function remains in the thin-walled portion 3, and the ultraviolet rays necessary for the curing reaction of the ultraviolet curable adhesive 7 can be transmitted.

  As a method of forming the groove 11 in the step (3), a method of mechanically grinding with a grinding tool 12 such as a diamond wheel can be applied. Details of each step will be described later.

  The processing amount of the groove 11 formed as described above, that is, the thickness of the thin portion 3 of the filter glass 1 is the thickness of the filter glass 1, the CuO content that is an infrared absorbing component described later, and the ultraviolet curable adhesive 7. The wavelength is adjusted as appropriate according to the wavelength and the integrated light amount required for the curing, the curing time required for the assembly process, and the like.

  The filter glass 1 of the present invention uses an infrared absorbing glass containing CuO (a fluorophosphate glass containing CuO or a phosphate glass containing CuO) as an essential constituent requirement.

The fluorophosphate glass used as the base glass has excellent weather resistance. Furthermore, by adding CuO to the glass, it is possible to absorb near infrared rays while maintaining high transmittance in the visible light range, and therefore it can be suitably used as the near infrared cut filter 1. Further, since the thermal expansion coefficient of the fluorophosphate glass is around 130 × 10 ⁻⁷ / ° C., the thermal expansion coefficient is close to that of the resin package that houses the solid-state image sensor 8, and as a window glass for a package of the solid-state image sensor 8. Can also be suitably used.

The phosphate glass used as the base glass has a higher hardness than the fluorophosphate glass and is less likely to break when an external force such as bending acts. Further, by adding CuO to the glass, near infrared rays can be absorbed while maintaining a high transmittance in the visible light range, and therefore, it can be suitably used as the near infrared cut filter glass 1. Further, since the thermal expansion coefficient of phosphate glass is around 80 × 10 ⁻⁷ / ° C., the thermal expansion coefficient is close to that of the alumina ceramic package that houses the solid-state image sensor 8, and the window glass for the package of the solid-state image sensor 8. Can also be suitably used.

The fluorophosphate-based glass used in the present invention can use a known glass composition as the near-infrared cut filter glass 1, but has a high content of the network structure forming component of the glass, particularly in terms of excellent processing strength. % _{in, P 2 O 5 46~70%,} MgF 2 0~25%, CaF 2 0~25%, SrF 2 0~25%, LiF 0~20%, 0~10% NaF, KF 0~10% However, the total amount of LiF, NaF and KF is 1 to 30%, AlF ₃ 0.2 to 20%, ZnF _{2 2 to} 15% (however, up to 50% of the total fluoride meter can be replaced with oxide) The composition is preferably contained. Moreover, it is preferable that the said fluorophosphate type | system | group accept | permits content of Ba and Pb only as an impurity.

  The reason why the content of each component of the fluorophosphate glass is limited to the above range is as follows.

P ₂ O ₅ is a main component that forms a network structure of glass. However, if it is less than 46%, the stability of the glass deteriorates, and the thermal expansion coefficient increases and the thermal shock resistance decreases. If it exceeds 70%, the chemical durability is lowered. Preferably it is 48 to 65%.

AlF ₃ is a component that improves the chemical durability and increases the viscosity of the glass. However, if it is less than 0.2%, the effect cannot be obtained, and if it exceeds 20%, vitrification becomes difficult. Preferably it is 2 to 15%.

MgF ₂ , CaF ₂ , SrF ₂ and BaF ₂ are effective in stabilizing the glass without deteriorating the chemical durability, but if each exceeds 25%, the melting temperature increases and devitrification occurs. It becomes easy. Preferably, MgF ₂ is 15% or less and CaF ₂ is in the range of 5 to 15%. SrF ₂ is also effective in improving the chemical durability of the glass, but when it exceeds 25%, the tendency to devitrification becomes strong. Preferably it is 10% or less.

  LiF, NaF, and KF are effective components for lowering the melting temperature. However, when LiF exceeds 20%, and NaF and KF each exceed 10%, the chemical durability decreases and the thermal shock resistance Decreases. Further, if the total amount of LiF, NaF, and KF is less than 1%, the effect of lowering the melting temperature cannot be obtained, and if it exceeds 30%, the chemical durability is remarkably lowered. Preferably, LiF is 4 to 15%, NaF is 5% or less, KF is 5% or less, and the total amount is 5 to 20%.

ZnF ₂ has the effect of improving the chemical durability and lowering the thermal expansion coefficient. However, if it is less than 2%, the effect cannot be obtained, and if it exceeds 15%, the glass becomes unstable. Preferably it is 2 to 10% of range.

It is also possible to replace up to 50% of the total fluoride meter with oxides. In this case, O increases the thermal shock resistance and contributes to the coloring of the glass with Cu ²⁺ ions. However, if it exceeds 50%, the melting temperature becomes high, ^leading to reduction of Cu ^{2+ and} the desired spectral transmission characteristics cannot be obtained.

In the fluorophosphate glass, it is preferable to allow the inclusion of Ba and Pb only as impurities. In the near-infrared cut filter glass based on the conventional fluorophosphate glass, Ba and Pb are contained as BaF ₂ and PbF ₂ for the purpose of stabilizing the glass and improving the weather resistance. When used as a window glass for a solid-state imaging device package, since it is required that the α dose emitted from the glass is low, it is preferable that BaF ₂ and PbF ₂ are not substantially contained. Moreover, it is preferable not to contain Pb also from an environmental pollutant viewpoint. For this reason, in this invention, it is preferable not to add Ba and Pb intentionally.

As the phosphate glass used in the present invention, a known glass composition can be used as a near-infrared cut filter glass. For example, in mass%, P ₂ O ₅ 70-85%, Al ₂ O ₃ 8-17. _{%, B 2 O 3 1~10%} , Li 2 O 0~3%, Na 2 O 0~5%, K 2 O 0~5%, Li 2 O + Na 2 O + K 2 O 0.1~5%, SiO It is preferable that it is a composition containing _{20 to} 3%.

The reason why the content of each component of the phosphate glass is limited to the above range is as follows.
P ₂ O ₅ is a main component constituting the glass network, but if it is less than 70%, the meltability deteriorates, and if it exceeds 85%, devitrification tends to occur.
Al ₂ O ₃ is an indispensable component for improving the chemical durability of the glass, but if it is less than 8%, there is no effect, and if it exceeds 17%, the meltability becomes poor.
B ₂ O ₃ improves the chemical durability and is an effective component for the stability of the glass. However, if it is less than 1%, there is no effect, and if it exceeds 10%, the tendency to devitrification increases.
Li ₂ O, Na ₂ O, and K ₂ O are added to improve the meltability of the glass and prevent devitrification. However, when the total amount of these components is less than 0.1%, there is no effect. If the content exceeds the above range, chemical durability deteriorates.
SiO ₂ has an effect of improving the chemical durability, but if it exceeds 3%, the chemical durability is extremely deteriorated.

  CuO contained in the basic glass composed of the fluorophosphate glass or phosphate glass described above is an essential component for near infrared cut. When CuO is not contained, although the amount of transmitted ultraviolet rays is increased, almost no near infrared rays can be cut, and the filter cannot have a near infrared ray cutting function. CuO is preferably contained in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of the basic glass made of fluorophosphate glass or phosphate glass. If CuO is less than 0.1 parts by mass, the near-infrared cut function cannot be sufficiently obtained. Moreover, when there is more CuO than 5 mass parts, an ultraviolet-ray cut function is high and sufficient ultraviolet-ray transmission amount cannot be obtained even if a peripheral part is made thin. In addition, the more preferable range of CuO is 0.3-2 mass parts.

  Next, the manufacturing method of the near-infrared cut filter glass 1 of Embodiment 1 is demonstrated. FIG. 4 is a flowchart showing an embodiment of a method for producing the near-infrared cut filter glass 1 according to the present invention.

  Hereinafter, the process flow from the glass raw material to the glass product will be briefly described with reference to FIG. First, a glass raw material is melted to obtain a plate-like glass 10 (a plate-like glass forming step). The plate-like glass 10 is cut into an appropriate size (for example, 150 mm square) from which a plurality of filter glasses 1 as final products can be collected. If necessary, the ridgeline part may be chamfered using a diamond wheel or the like, or the glass may be immersed in an etching solution, and the ridgeline part may be etched (etching) for the purpose of preventing damage in the subsequent polishing process. Process). The light-transmitting surface of the plate-like glass 10 is polished and finished to a mirror surface (polishing step), and the plate-like glass 10 is cleaned to sufficiently remove abrasives and polishing debris and dry (first cleaning) Process). Next, lattice-like grooves 11 are formed on one light-transmitting surface (groove forming step). Further, it is cut and separated along the center line of the groove 11 formed in the previous step (cut and separated step). The glass is washed again, and the grinding waste in the groove forming step and the cutting step is removed and then dried (second washing step). As a result, a filter glass 1 having a frame-like thin portion 3 formed thinner on one surface than the plate thickness of the optically effective portion is obtained.

  In the plate-like glass forming step, the prepared glass raw material is melted in a glass melting furnace, and the molten glass flows out of the glass melting furnace into a forming die and is formed into a plate-like glass 10. Or after shape | molding to block-shaped glass, it cut | disconnects in plate shape.

  The polishing process uses a known polishing apparatus and polishing method to polish the plate-like glass 10 in each of the stages of rough polishing, intermediate polishing, and mirror finish, for example, thereby achieving good dimensional accuracy. And a good finished surface can be obtained.

  In the first and second cleaning steps, the abrasive, polishing waste and grinding waste used for polishing are removed by cleaning. For example, the plate-like glass 10 is accommodated and held in a cage having a holding portion that holds the glass plates one by one, and the cage is sequentially immersed in an ultrasonic cleaning tank for cleaning, and finally isopropyl alcohol ( IPA) A method of washing and drying can be used.

  The groove forming step can be performed by grinding the surface layer of one light-transmitting surface of the plate-like glass 10 to a desired depth, and a known grinding device or cutting device can be used. In the following, a case where the surface layer of the plate-like glass 10 is ground using a cutting device used for cutting a silicon wafer or the like will be described as an example.

  The cutting device includes a disc-shaped grinding wheel 12 such as a diamond wheel and a substrate holder installed below the grinding wheel 12. In such a cutting device, the substrate holder is raised (or the grinding wheel is lowered) while the disc-shaped grinding wheel 12 is rotated, and the plate-like glass 10 mounted on the substrate holder is moved to the cutting edge of the grinding wheel 12 ( The plate-like glass 10 is cut by bringing the substrate holder in contact with the grinding wheel 12 in this state. In the method of the present invention, the surface layer of the plate-like glass 10 is ground by setting the position of the cutting edge of the grinding wheel 12 within the plate thickness of the plate-like glass 10. Since the substrate holder positions the grinding position of the plate-like glass 10 by the grinding wheel 12, the plate-like glass 10 held by the substrate holder can be moved along the surface thereof. In order to adjust the grinding direction by 12, the plate-like glass 10 can be rotated about an axis perpendicular to the surface thereof. Since such a cutting apparatus is well known, the detailed description of its configuration and operation will be omitted.

  In the groove forming step, first, the plate-like glass 10 after the first cleaning step after the polishing step is mounted on the substrate holder of the cutting apparatus. Next, the substrate holder is raised while the disk-shaped grinding wheel 12 is rotated, the plate-shaped glass 10 is brought into contact with the cutting edge of the grinding wheel 12, and the substrate holder is moved with respect to the grinding wheel 12 to form grooves. 11 is formed. Thereafter, this operation is repeated to form a plurality of grooves 11 on the surface of the plate-like glass 10, and then the substrate holder is rotated by 90 degrees, and the above operation is further repeated, as shown in FIG. A plate-like glass 10 in which the grooves 11 are formed is obtained. The groove forming step can be performed so that the outer edge of the plate-like glass 10 becomes the groove 11 as shown in FIG. 8 (perspective view), but in this case, since the thin-walled portion remaining after grinding is easy to break, As shown in FIG. 6, it is preferable to form the groove | channel 11 leaving a thick part in the outer edge of the plate-shaped glass 10. As shown in FIG.

  The width of the groove 11 formed here is the blade width of the grinding wheel 12 so that the width of the thin portion 3 necessary for sealing with the package 9 can be obtained in the filter glass 1 obtained through the subsequent cutting step. Set by selecting. Further, the interval between the grooves 11 is set so that a necessary optically effective portion is obtained in accordance with the size of the package 9 in which the filter glass 1 is sealed. As shown in FIG. 3, when the step 2 is sealed so as to be fitted into the opening of the package 9, the size of the optically effective portion on the glass surface defined by each groove 11 is The groove interval is set so as to be slightly smaller than the inner size of the opening of the package 9. This facilitates the alignment of the package 9 and the filter glass 1 during sealing, and prevents the adhesive 7 from protruding to the inner surface of the package 9. In addition, when the surface on which the step portion 2 is not formed is sealed to the outer frame of the package 9 as shown in FIG. 9, the width of the thin portion 3 necessary for sealing with the package 9 is ensured. It is desirable to process so that the size of the optically effective portion of the surface of the plate-like glass 10 defined by the groove 11 is equal to or larger than the inner size of the opening of the package 9. As a result, the light transmitted through the thin portion 3 and the stray light incident from the side surface of the stepped portion 2 are prevented from entering the image sensor, and good color reproducibility of the captured image can be maintained.

  The cutting / separating step can be performed using a cutting device similar to that used in the groove forming step. In the case of cutting and separating, a grinding wheel 12 having a narrower blade width than that used in the groove forming step is used, and the center line (see FIG. A plate-like glass 10 is cut along a dotted line) and separated into a final product size filter glass 1.

  Further, in addition to the process flow of FIG. 4, as shown in FIG. 5, a process of forming an optical thin film having an ultraviolet cut function on one surface of the plate-like glass 10 following the first cleaning process (film formation process). You may have. The film forming step is a step of forming an optical thin film having an ultraviolet ray cutting function on a plate surface of the plate-like glass 10 that has been polished, washed and dried by using a vacuum vapor deposition device or a sputtering device. In addition, when the optical thin film was formed on the plate-like glass 10, in the next groove forming step, the surface on which the optical thin film was formed was mounted toward the grinding wheel side, and finally cut and separated. The optical thin film is removed only in the thin portion 3 in the subsequent filter glass 1. As a result, the optically effective portion where the optical thin film remains has an ultraviolet cut function, and the thin portion 3 can transmit ultraviolet rays.

  FIG. 2 is a longitudinal sectional view of the near-infrared cut filter glass 1 produced as described above, and FIG. 3 is a longitudinal sectional view showing a state in which the filter glass 1 is sealed in the package 9 of the solid-state imaging device 8. . As shown in the drawing, the filter glass 1 of the first embodiment has a thin portion 3 corresponding to the sealing portion, so that the portion has a high ultraviolet transmittance and uses an ultraviolet curable adhesive 7 as will be described later. Thus, when sealing, the necessary amount of ultraviolet rays reaching the adhesive 7 can be secured, and the solid-state image sensor device 100 can be efficiently assembled.

  As shown in FIG. 3, when sealing the step portion 2 so as to be fitted into the opening portion of the package 9, the step portion 2 of the filter glass 1 is placed when the filter glass 1 is placed in the opening portion of the package 9. Positioning can be performed accurately and easily by being inserted into the opening of the package 3. In this case, a part of the thickness of the optically effective portion of the filter glass 1 (for the depth of the groove) is present in the package 9, so that the thickness of the solid-state image sensor device 100 can be reduced. it can.

  Furthermore, since the grooves are formed using the grinding wheel 12 in the above process, the ground surfaces of the stepped portion 2 and the thin portion 3 in the filter glass 1 are rougher than the optically polished translucent surface. ing. For this reason, the bonding area of the sealing portion sealed in the package can be increased as compared with a normal polished surface, and a sufficient anchor effect with the sealing adhesive 7 can be expected. Can be improved. Further, as shown in FIG. 3, when sealing the step portion 2 so as to fit into the opening portion of the package 9, the conventional configuration in which the filter glass 1 is sealed so as to cover the opening portion of the package 9. Then, the end face of the near-infrared cut filter 1 which did not exist is arranged inside the package 9 as the stepped portion 2. If the end surface serving as the stepped portion 2 is a flat polished surface, light obliquely incident on the near-infrared cut filter glass 1 may be reflected by the end surface and incident on the solid-state imaging device 8, thereby degrading the image quality of the image. However, in the embodiment of the present invention, since the end surface to be the stepped portion 2 is a rough surface as described above, the light incident on the end surface is scattered and the component incident on the solid-state imaging device 8 is reduced. be able to. In addition, if the end surface used as the step part 2 is inked, internal reflection can be further suppressed by absorption.

  Moreover, you may have the alkali etching process of immersing the filter glass 1 after a groove | channel formation process or a cutting-and-separation process for the predetermined time in the etching liquid which consists of alkaline aqueous solution warmed from normal temperature to about 80 degreeC. When the filter glass 1 or the plate-like glass 10 is polished, formed into grooves, or cut and separated, microcracks are generated on the end face of the glass or the thin-walled portion 3, and this crack may reduce the bending strength of the filter glass 1. . By performing an alkali etching process, by removing these micro cracks or blunting the crack tip, the possibility of becoming a starting point of breakage when bending stress is applied is reduced, and thus the bending strength of the filter glass 1 is reduced. Can be improved. In the alkali etching process, the etching solution does not completely flatten the end face of the filter glass 1 or the thin part 3, so the light scattering effect on the end face that becomes the stepped part 2 is not lost.

  The reason for using an etching solution comprising an alkaline aqueous solution in the alkali etching process is that even if the optically effective portion after the polishing process is etched without performing a protective treatment such as masking, micro cracks generated in the polishing process etc. are surely obtained. This is because it is removed and the optically effective portion is not affected by surface roughness. Thereby, the process of protecting the optically effective portion is unnecessary, and the manufacturing process can be simplified. In the etching solution comprising an aqueous alkali solution used in the alkali etching step, the alkali component is KOH, and other components include surfactants (such as triethanolamine and benzyl alcohol), water, and the like.

  Further, as shown in FIG. 11, a taper 14 whose diameter is reduced toward the second light transmitting surface 6 (inner surface) facing the solid-state imaging device 8 may be formed in the stepped portion 2. In this case, as the disk-shaped grinding wheel 12 used in the groove forming step, the taper 14 can be easily formed by grinding using a rotating grinding wheel whose thickness decreases toward the peripheral end illustrated in FIG. By providing the step 2 with the taper 14 as described above, positioning into the package 9 is facilitated, and light obliquely incident on the optically effective portion of the near-infrared cut filter glass 1 hits the taper 14. Even in this case, the light is reflected on the incident surface side and the reflected light does not easily enter the solid-state imaging device 8. Further, when the thin portion 3 is formed by grinding, stress concentration is likely to occur at the corners of the thin portion 3 and the original thickness portion, and there is a drawback that the thin portion 3 is easily cracked by an impact such as during handling, but the step portion 2 has a taper 14. By doing so, stress relaxation can be achieved, and the effect of making it difficult to break can also be obtained. As the shape of the taper 14, in addition to the linear taper 14 shown in FIG. 11, by selecting the shape of the grinding wheel 12, the same effect can be obtained as a continuous curved surface shown in FIG. In order to further improve the positioning and accuracy at the time of assembling the filter glass, it is preferable that the opening of the package 9 has a shape that matches the tapered shape of the filter glass 1.

  FIG. 9 is a longitudinal sectional view showing a state where the surface on which the step portion 2 is not formed is sealed with the outer frame of the package 9. Even in the case of sealing as described above, the thin portion 3 corresponding to the sealing portion is thin, so that the ultraviolet transmittance of this portion is high, and the solid-state image sensor device 100 can be efficiently assembled by the ultraviolet curable adhesive 7. Can be done. Also in this case, as shown in FIG. 11, it is possible to form a taper 14 that is reduced in diameter toward the first light-transmitting surface 5 side that is the outer surface when sealed in the package 9. Forming the taper 14 makes it difficult for light incident obliquely to the optically effective portion of the near-infrared cut filter glass 1 to be reflected in the direction of the solid-state imaging device 8. In this case, it is preferable to sanitize the taper 14 so that incident light from the taper 14 does not enter the solid-state imaging device 8.

<Example 1>
Next, Example 1 based on Embodiment 1 will be described.
As a glass having a near-infrared cut function, a fluorophosphate glass (NF-50, manufactured by AGC Techno Glass Co., Ltd.) is used, and a glass containing 1.2% by mass of CuO contained in the fluorophosphate glass is prepared. did. This glass is adjusted so as to have a spectral transmittance characteristic capable of obtaining a desired visibility correction at a plate thickness of 1 mm when mounted on the solid-state imaging device 8.

  Using this glass, a near-infrared cut filter glass 1 was prepared according to the process described in the first embodiment. First, molten glass is continuously formed to have a plate thickness of about 2 mm and a plate width of more than about 150 mm, both ends are cut to a plate width of 150 mm, and this is cut every 150 mm to obtain a plate-like glass 10. Next, both sides of this plate-like glass 10 are polished and washed until the thickness becomes 1 mm, and then one surface layer is ground to form the grooves 11. The groove interval is set according to the package size of the solid-state imaging device 8, and the groove width is set according to the sealing surface with the package 9. For example, when the sealing surface width with the package 9 is 1.5 mm, the groove width to be ground is set to 1.5 mm × 2 + final cutting margin, and cutting is performed using the grinding wheel 12 suitable for the groove width. Further, as the grinding depth is increased, the thickness of the thin portion becomes thinner and the ultraviolet transmittance can be increased, but at the same time the strength and yield tend to decrease. Grinding was performed so that the thickness of the thin portion was 5 mm, that is, 5 mm. Subsequently, it cut | disconnected and separated along the centerline of the grinding groove | channel, the grinding waste was wash | cleaned and dried, and the near-infrared cut filter glass 1 was obtained.

  Using the V-570 type UV-visible near-infrared spectrophotometer (manufactured by JASCO Corporation), the spectral transmittance of the optically effective portion of the near-infrared cut filter glass 1 prepared as described above and the thin-walled portion serving as the sealing portion is used. Measured respectively. The result is shown in FIG. FIG. 23A shows the spectral transmittance in the wavelength range from the ultraviolet region to the infrared region for each measurement site, and FIG. 23B shows the spectral transmittance obtained by enlarging only the ultraviolet region in FIG. FIG.

  From the spectral transmittance in FIG. 23, for example, at 320 nm, the optically effective portion with a plate thickness of 1 mm has a transmittance of less than 10%, the thin portion with a plate thickness of 0.5 mm exceeds 30%, and the optical thickness with a plate thickness of 1 mm at 330 nm. It can be seen that the transmittance of about 30% in the effective portion is improved to about 60% in the thin portion having a thickness of 0.5 mm. Since there is a certain range of effective wavelengths for curing the ultraviolet curable adhesive, the curing time of the ultraviolet curable adhesive can be significantly shortened by increasing the transmittance in the entire ultraviolet region.

Next, a case where the solid-state imaging device package 9 is hermetically sealed using the near infrared cut filter glass 1 will be described.
For near-infrared cut filter glass 1 (fluorophosphate-based glass, CuO content: 1.2 mass%, plate thickness 1 mm), thin-walled portion 3 is formed and the thickness of the sealed portion is reduced to 0.5 mm Then, the thin part 3 was not formed and the whole thickness was 1 mm.
An ultraviolet curable adhesive 7 is applied to the opening of the package 9 with which the thin-walled portion 3 of the near-infrared cut filter glass 1 comes into contact using a dispenser. Next, the near-infrared cut filter glass 1 is placed on top of the package 9. Next, the adhesive 9 was cured by irradiating the package 9 on which the near-infrared cut filter glass 1 was placed with ultraviolet rays from an ultraviolet lamp, and the near-infrared cut filter glass 1 was adhered to the package 9. Under the present circumstances, it investigated about the time required for adhesion | attachment of the near-infrared cut filter glass 1, ie, the time which the adhesive agent 7 hardened | cured.
The time required for adhesion was about 40% shorter when the near-infrared cut filter glass 1 with the thin-walled portion 3 was used than when the near-infrared cut-off filter glass 1 without the thin-walled portion 3 was used. The curing of the ultraviolet curable adhesive 7 depends on the accumulated amount of ultraviolet light. The accumulated amount of ultraviolet light is the product of the ultraviolet intensity and the irradiation time. When the ultraviolet intensity is low, a long irradiation time is required. The near-infrared cut filter glass 1 in which the thin-walled portion 3 is formed has a high ultraviolet intensity reaching the adhesive 7 because the amount of ultraviolet rays absorbed by the glass is less than that of the optically effective portion, and is considered to be able to be cured in a short time. Therefore, even if the thickness of the thin portion 3 is other than that described above, the same effect can be obtained if the thickness of the thin portion 3 is thinner than the optically effective portion and the amount of ultraviolet absorption is small.

<Embodiment 2>
Next, Embodiment 2 will be described.
FIG. 14 is a perspective view showing Embodiment 2 of the near-infrared cut filter glass 21 of the present invention. FIG. 16 is a solid view in which the near-infrared cut filter glass 21 of the present invention is sealed in the opening of the package 9 of the solid-state image sensor 8. 1 is a longitudinal sectional view of an image sensor device 100. FIG.

  The near-infrared cut filter glass 21 of the second embodiment (hereinafter sometimes abbreviated as filter glass 21) has a rectangular plate-like appearance as shown in FIGS. 14 to 16 and is sealed in the package 9. Further, the optically effective portion 22 at the center of the plate surface covering the opening of the package 9 and the frame-shaped peripheral edge portion 23 serving as a sealing surface with the package 9 are integrally formed. The optically effective portion 22 refers to a range in which light incident on the solid-state imaging device 8 is transmitted through the filter glass 21, and refers to the inside of the sealing surface between the filter glass 21 and the package 9. The peripheral portion 23 refers to the outer periphery of the optically effective portion 22 and includes a range where the adhesive 7 provided between the filter glass 21 and the package 9 adheres.

  The optically effective portion 22 is made of a near-infrared cut glass containing CuO in a fluorophosphate-based glass or a phosphate-based glass in order to have a predetermined near-infrared cut function, and the peripheral portion 23 is formed of the optically effective portion. It is made of a glass whose ultraviolet transmittance is increased by containing less CuO than the glass constituting the portion 22 or not containing CuO. Therefore, in the filter glass 21 of the second embodiment, the optically effective portion 22 is increased by increasing the ultraviolet transmittance at the peripheral portion 23 that does not affect the light incident on the solid-state imaging device 8 as compared with the ultraviolet transmittance of the optically effective portion 22. In this case, while maintaining necessary transmission characteristics, the amount of ultraviolet light transmitted through the peripheral portion 23 where the adhesive 7 is provided is increased, and sufficient ultraviolet light reaches the adhesive 7 provided at the peripheral portion 23 of the filter glass 21. Thus, the curing time of the adhesive 7 can be shortened, and the filter glass 21 and the package 9 can be assembled efficiently.

  The glass constituting the peripheral portion 23 only needs to be transparent to ultraviolet rays, but for example, the same raw material as the glass constituting the optically effective portion 22 is used and melted without adding an ultraviolet absorbing component such as CuO. Glass can be used. By doing so, the viscosity characteristic and the expansion characteristic of the glass constituting the optically effective portion 22 and the glass constituting the peripheral edge portion 23 can be made almost equal, and even when both are integrated, no distortion remains inside. The molding process described later can be easily performed, and the optical influence due to stress can be eliminated. In addition, as glass which comprises the optical effective part 22, the glass similar to what was explained in full detail in the said Embodiment 1, ie, the glass which made CuO contain the fluorophosphate glass or phosphate glass can be used.

The near-infrared cut filter glass 21 as described above can be manufactured as follows.
(1) Melting infrared-absorbing glass containing CuO, creating a square columnar glass rod 24, and optically polishing the outer peripheral four surfaces;
(2) a step of melting and molding a glass having a CuO content less than that of the infrared absorbing glass or not containing CuO to form a glass plate 25, and optically polishing at least two adjacent surfaces;
(3) A step of creating a base material 29 in which the polished surfaces of the glass plate member 25 are joined to the polished surfaces of the square columnar glass rod 24 to surround the four outer surfaces of the glass rod 24,
(4) a step of heating and stretching the base material 29 to a predetermined dimension;
(5) a step of cutting the stretched base material in a direction perpendicular to the stretching axis to form a flat glass 28;
(6) A step of optically polishing both surfaces of the flat glass 28.
Hereinafter, the process flow from the glass raw material to the glass product will be briefly described with reference to FIG.
First, as the glass constituting the optically effective portion 22, a glass raw material containing CuO is melted to form a square columnar glass rod 24, and then the outer peripheral four surfaces of the glass rod 24 are optically polished to constitute the optically effective portion. A glass rod 24 is obtained (glass rod molding step).

On the other hand, as the glass constituting the peripheral portion 23, a glass similar to the glass constituting the optically effective portion 22 is used and a glass melted without adding an ultraviolet absorbing component such as CuO is formed into a flat plate shape. Two adjacent surfaces are optically polished to obtain a glass plate material 25 constituting the peripheral portion (glass plate material forming step).
At this time, it is preferable to prepare the glass raw material preparation equipment and the crucible or melting furnace for melting the glass separately from those used for melting the glass containing CuO in order to prevent mixing of ultraviolet absorbing components such as CuO.

  The width | variety of the glass plate material 25 shall be the length which added the thickness of the glass plate material 25 to the one side of the said glass rod material 24 joined later. When the cross-sectional shape of the glass rod 24 is a rectangle, the glass plate 25 includes two sheets having a width obtained by adding the thickness of the glass plate 25 to the length of the long side of the rectangle, and the length of the short side of the rectangle. Two sheets having a width obtained by adding the thickness of the glass plate material 25 to each other are prepared. Alternatively, two pieces having a width obtained by adding the thickness of two pieces of the glass plate 25 to the length of the long side or the short side of the glass rod 24 and the same width as the length of the short side or the long side of the glass rod 24 Two things may be sufficient.

  In the glass plate material forming step, at least two adjacent surfaces of the glass plate material 25 are optically polished when the glass rod material and the glass plate material 25 are subsequently joined without causing any gaps between the joint surfaces. Because. Preferably, both plate surfaces of the glass plate material 25 and two end surfaces which are usually on the long side of the plate surface are polished. As a result, the outer peripheral surface of the final product also becomes a clean polished surface, and an accurate outer shape and size can be obtained.

  Next, as shown in FIG. 20, the glass rod 24 and the glass plate 25 are brought into contact with the respective polished surfaces, and the outer periphery of the glass rod 24 is surrounded by the glass plate 25 before stretching. (Stretching base material creation process). At this time, it is not necessary to use an adhesive or the like on the joint surface between the glass rod 24 and the glass plate 25. This is because the precisely polished plane is brought into close contact with the optical contact and integrated into a state where it cannot be completely separated after a subsequent stretching process. In the glass rod forming step and the glass plate forming step, the glass rod material is formed so that the cross-sectional shape perpendicular to the major axis of the glass rod material 24 of the stretched base material 29 thus formed is similar to the final product shape. 24 and the size of the glass plate 25 are determined.

  Next, the stretched base material 29 is placed in a heater and stretched by heating to a predetermined size (stretching step). FIG. 22 shows an outline of a stretching apparatus used in the stretching process. The stretching apparatus includes a heater 31, a base material 29, a base material support portion 33, a base material stretching portion 34, an outer diameter (thickness) control portion 35, and the like. The stretch processing method of Embodiment 2 basically uses a known redraw processing method. The redrawing process is a method of manufacturing a thin product by holding a primary molded base material vertically and heating the lower end of the base material to lower the viscosity of the glass and pull it down. That is, first, as shown in FIG. 22 (A), the stretched base material 29 is placed in a heater 31. The upper end of the base material 29 is set on the support portion 33, and the extending portion 34 is attached to the lower end thereof. The extending portion 34 is provided so as to be movable up and down by a driving device (not shown). In this state, the base material 29 is heated by the heater 31 to be softened, and the driving unit is operated to lower the extending portion 34. Then, as shown in FIG. 22 (B), the base material 29 is drawn into a thin prismatic shape. While the length of one side of the stretched part is detected by the outer diameter (thickness) control unit 35, the stretching speed of the stretching unit 34 by the driving device is controlled so that the length of one side of the rectangular column of the stretched part is constant. . Further, the stretched portion of the base material 29 is cut into a certain length, and the near infrared cut filter glass rod 26 whose outer shape (long side, short side) becomes the product dimension is obtained.

  At this time, when the non-joint surface of the glass plate material 25 constituting the peripheral portion 23 is not polished, the outer peripheral surface of the stretched base material 29 is rough, but is softened and stretched by heat stretching, Even minute irregularities and scratches on the surface are stretched, and for example, the tip of the scratch is blunted from an acute angle, and as a result, the strength of the glass is improved. In addition, the filter glass 21 manufactured by this method has an advantage that even if a crack is generated from the outer peripheral surface, the extension of the crack is hindered at the bonding interface between the glass rod 24 and the glass plate 25 and the optically effective portion 22 is protected. There is.

  Next, the near-infrared cut filter glass rod 26 drawn using a known cutting device is cut in a direction perpendicular to the drawing axis to form a flat glass 28 (cutting separation step).

  The cut flat glass 28 optically polishes both cut surfaces (polishing step). The polishing process is performed by using a known polishing apparatus and polishing method, for example, in stages of rough polishing, intermediate polishing, and mirror finish, thereby obtaining good dimensional accuracy and a good finished surface. . Thereafter, the flat glass 28 is washed to sufficiently remove abrasives and polishing debris and dried. If necessary, the ridge line portion is chamfered, rewashed and dried to obtain a filter glass 21 as a final product.

  By making the composition of the glass rod 24 and the glass plate 25 the same base material composition excluding CuO, there is no difference in the polishing rate between the optically effective portion 22 and the peripheral portion 23 in the polishing step, and the optically effective A good polished surface having no step at the boundary between the portion 22 and the peripheral portion 23 can be obtained.

  As described above, the optically effective portion 22 is made of a CuO-containing glass having a near-infrared cutting function, and the frame-shaped peripheral edge portion 23 is made of glass that does not contain CuO, that is, is made of glass having an increased ultraviolet transmittance. An infrared cut filter glass 21 is obtained.

  FIG. 14 is a perspective view of the near-infrared cut filter glass 21 prepared as described above, and FIG. 16 is a longitudinal sectional view showing a state in which the filter glass 21 is sealed in the package 9 of the solid-state imaging device 8. As shown in the drawing, the filter glass 21 of the second embodiment is made of a glass having a relatively high ultraviolet transmittance in which the peripheral portion 23 corresponding to the sealing portion does not contain CuO. Therefore, the filter glass 21 is sealed using the ultraviolet curable adhesive 7. When stopping, the necessary amount of ultraviolet rays reaching the adhesive 7 can be secured, and the solid-state image sensor device 100 can be efficiently assembled. Note that the glass of the optically effective portion 22 containing CuO needs to have a larger area than the opening of the package 9. If the glass of the optically effective part 22 containing CuO is smaller than the opening of the package 9, that is, the glass of the peripheral part 23 not containing CuO is applied to the opening of the package 9 and is not absorbed by the glass. This is because infrared rays are incident on the solid-state imaging device 8.

<Example 2>
Next, Example 2 based on Embodiment 2 will be described. As the glass constituting the optically effective portion 22 of the near-infrared cut filter glass 21, a fluorophosphate glass (NF-50, manufactured by AGC Techno Glass Co., Ltd.) is used as in Example 1 described above. What prepared the quantity of CuO to contain to 1.2 mass% was prepared. After melting, this glass was cast into a block shape, cut into a rectangular column shape having a long side of 60 mm, a short side of 50 mm, and a length of 400 mm, and a glass rod 24 having an optically polished outer peripheral surface was prepared.

  On the other hand, as the glass constituting the peripheral portion 23, glass melted without adding CuO from the above-mentioned fluorophosphate glass (NF-50, manufactured by AGC Techno Glass Co., Ltd.), cast into a block shape, and then width 67 A glass plate 25 was prepared by cutting and polishing a 5 mm, 7.5 mm thick, 400 mm long plate and a 57.5 mm wide, 7.5 mm thick, 400 mm long plate.

  Next, as shown in FIG. 20, the glass rod 24 and the glass plate 25 are brought into contact with and bonded to each other, and the outer periphery of the glass rod 24 is surrounded by the glass plate 25. A stretched base material 29 having a side of 65 mm and a length of 400 mm was prepared. This stretched base material 29 is stretched by heating (redraw), formed into a rod having a long side of 15 mm and a short side of 13 mm, cut into a thickness of about 1.5 mm using a known cutting device, and both cut surfaces are optically cut. The filter glass 21 having a thickness of 1 mm was obtained by polishing, washing and drying. The finally obtained filter glass 21 has the optically effective portion 22 made of CuO-containing glass having a long side of 12 mm, a short side of 10 mm, and the width of the peripheral portion made of CuO-free glass serving as a sealing portion with the package 9. Becomes a 1.5 mm rectangular plate.

  The spectral transmittance of the optically effective part 22 made of CuO-containing glass of the near-infrared cut filter glass 21 prepared as described above and the peripheral part 23 made of CuO-free glass serving as a sealing part of the package 9 is represented by V-570. Each was measured using a type ultraviolet visible near infrared spectrophotometer (manufactured by JASCO Corporation). The result is shown in FIG. FIG. 24 is a diagram showing the spectral transmittance obtained by enlarging only the ultraviolet region of each glass.

  From the spectral transmittance of FIG. 24, for example, at 300 nm, the optically effective portion 22 containing CuO has a transmittance of 0%, the peripheral portion 23 not containing CuO is more than 60%, and at 330 nm, the optically effective portion 22 has about It can be seen that the transmittance of 30% is improved to more than 80% in the peripheral portion 23. Since the effective wavelength for curing the ultraviolet curable adhesive 7 has a certain range, the transmittance increases in the entire ultraviolet region, thereby significantly shortening the curing time of the ultraviolet curable adhesive 7. it can.

Next, a case where the package 9 is hermetically sealed using the near infrared cut filter glass 21 will be described.
A near-infrared cut filter glass 21 of Example 2 and a glass made of only glass constituting the optically effective portion 22 of the near-infrared cut filter glass 21 and polished to a thickness of 1 mm were prepared as comparative examples.

The ultraviolet curable adhesive 7 is applied to the opening of the package 9 with which the peripheral edge 23 of the near-infrared cut filter glass 21 abuts using a dispenser. Next, the glass coated with the adhesive 7 is placed on the upper part of the package 9. Subsequently, the package 9 on which the glass was placed was irradiated with ultraviolet rays by an ultraviolet lamp to cure the adhesive 7, and the glass was adhered to the package. At this time, the time required for bonding the glass, that is, the time when the adhesive 7 was cured was investigated.
The time required for bonding the glass was about 50% shorter when the glass of the example was used than when the glass of the comparative example was used.

  In Example 2 described above, an example using a fluorophosphate glass was described. However, the fluorophosphate glass has a steep slope of the viscosity curve, and redraw molding requires very strict temperature control. Therefore, in the second embodiment, it is preferable to use a phosphate-based glass whose viscosity curve has a gentle slope as compared with a fluorophosphate-based glass.

<Embodiment 3>
Next, Embodiment 3 will be described.
FIG. 25 is a perspective view showing Embodiment 3 of the near-infrared cut filter glass 41 of the present invention. The near-infrared cut filter glass 41 of the third embodiment (hereinafter sometimes abbreviated as filter glass 41) has a rectangular plate-like appearance as shown in FIG. A CuO-containing glass 42 constituting an optically effective portion at the center of the plate surface covering the opening of the substrate and a UV transmissive glass 43 including a peripheral portion that is larger than the CuO-containing glass 42 and serves as a sealing surface for the package 9 are laminated. Consists of states. The optically effective portion refers to a range in which light incident on the solid-state imaging element 8 is transmitted through the filter glass 41, and refers to the inside of the sealing surface between the filter glass 41 and the package 9. Further, the peripheral portion refers to the outer periphery of the optically effective portion, and includes a range to which the adhesive 7 provided between the filter glass 41 and the package 9 adheres.

  The CuO-containing glass 42 is made of a near-infrared cut glass in which CuO is contained in a fluorophosphate-based glass or a phosphate-based glass in order to have a predetermined near-infrared cut function. The UV transmissive glass 43 is made of a glass having an ultraviolet transmittance increased by having less CuO content than the CuO-containing glass 42 or not containing CuO. Therefore, in the filter glass 41 of Embodiment 3, it is necessary in the optically effective portion by increasing the ultraviolet transmittance at the peripheral portion that does not affect the light incident on the solid-state imaging device 8 compared to the ultraviolet transmittance of the optically effective portion. Adhesive 7 can be obtained by increasing the amount of ultraviolet light transmitted at the peripheral edge where the adhesive 7 is provided while maintaining sufficient transmission characteristics, and allowing sufficient ultraviolet light to reach the adhesive 7 provided at the peripheral edge of the filter glass 41. Therefore, the filter glass 41 and the package 9 can be efficiently assembled.

  The UV transmissive glass constituting the peripheral portion may be any glass that is transparent to ultraviolet rays. For example, the same raw material as the CuO-containing glass 42 constituting the optically effective portion is used, and no ultraviolet absorbing component such as CuO is added. Glass melted can be used. By doing so, the viscosity characteristics and the expansion characteristics of the CuO-containing glass 42 constituting the optically effective part and the UV transmitting glass 43 constituting the peripheral part can be made substantially equal, and the optical influence by these can be eliminated. . In addition, as glass which comprises the CuO containing glass 42, the glass similar to what was explained in full detail in the said Embodiment 1, ie, the glass which made CuO contain the fluorophosphate glass or phosphate glass can be used.

The near-infrared cut filter glass 41 as described above can be manufactured as follows.
(1) melting infrared absorbing glass containing CuO to obtain a plate-like CuO-containing glass 42;
(2) a step of obtaining a plate-shaped UV transmitting glass 43 by melting a glass having a CuO content less than that of the infrared absorbing glass or not containing CuO,
(3) a step of optically polishing both surfaces of the CuO-containing glass 42 and the UV transmitting glass 43;
(4) A step of adhering the CuO-containing glass 42 in a state where a sealing portion with the package 9 is left at a substantially central portion of the UV transmissive glass 43.

  FIG. 26 is a longitudinal sectional view showing a state in which the filter glass 41 is sealed in the package 9 of the solid-state imaging device 8. As illustrated, the filter glass 41 of the third embodiment is sealed using the ultraviolet curable adhesive 7 because the peripheral portion corresponding to the sealing portion is made of the UV transmissive glass 43 having a relatively high ultraviolet transmittance. At this time, a necessary amount of ultraviolet rays reaching the adhesive 7 can be secured, and the solid-state image sensor device 100 can be efficiently assembled. Note that the CuO-containing glass 42 preferably has a size approximately equal to the opening area of the package 9. This is because if the size of the CuO-containing glass 42 is smaller than the opening area of the package 9, the UV transmissive glass 43 is applied to the opening part of the package 9, and unnecessary infrared rays enter the solid-state imaging device 8 from that part. In addition, if the size of the CuO-containing glass 42 is too large than the opening area of the package 9, the CuO-containing glass 42 is applied to the sealing portion, and the ultraviolet rays applied to the adhesive 7 are absorbed by the CuO-containing glass 42. It is.

<Example 3>
Next, Example 3 based on Embodiment 3 will be described. As the CuO-containing glass 42 constituting the optically effective portion of the near-infrared cut filter glass 41, a fluorophosphate glass (NF-50, manufactured by AGC Techno Glass) is used as in the first embodiment, and this fluorophosphate glass is used. What prepared the quantity of CuO contained in glass as 1.2 mass% was prepared. This glass was formed into a plate-like glass having a thickness of 1 mm and a size of 10 mm × 10 mm and optically polished on both sides according to the above-described steps.

  On the other hand, as the UV transmissive glass 43 constituting the peripheral portion, a glass melted without adding CuO from the above fluorophosphate glass (NF-50, manufactured by AGC Techno Glass Co., Ltd.), in the same process as above, It was formed into a plate-like glass having a thickness of 1 mm and a size of 14 mm × 14 mm and optically polished on both sides.

  Then, an ultraviolet curable resin adhesive is applied to one surface of the CuO-containing glass 42, and the CuO-containing glass 42 is placed in a state where a 2 mm non-adhesive portion is provided on the entire circumference of the UV transmitting glass 43, and irradiated with ultraviolet rays By doing so, the adhesive was cured, and both were laminated and integrated.

Next, the case where the package 9 is hermetically sealed using the near infrared cut filter glass 41 will be described.
A comparative example was prepared by polishing the near-infrared cut filter glass 41 of Example 3 above and the CuO-containing glass 42 constituting the optically effective portion of the near-infrared cut filter glass 41 and polishing the entire thickness to 1 mm.

The ultraviolet curable adhesive 7 is applied to the opening of the package 9 with which the peripheral edge of the near infrared cut filter glass 41 abuts using a dispenser. Next, the glass coated with the adhesive 7 is placed on the upper part of the package 9. Subsequently, the package 9 on which the glass was placed was irradiated with ultraviolet rays by an ultraviolet lamp to cure the adhesive 7, and the glass was adhered to the package. At this time, the time required for bonding the glass, that is, the time when the adhesive 7 was cured was investigated.
The time required for bonding the glass was about 50% shorter when the glass of Example 3 was used than when the glass of the comparative example was used.
In addition, although the example which used the fluorophosphate type glass as the CuO containing glass 42 or the UV transmissive glass 43 was demonstrated in the said Example 3, you may use phosphate type glass. In FIG. 26, the CuO-containing glass 42 is on the solid-state image sensor side, but the UV transmissive glass 43 may be on the solid-state image sensor side.

  According to the near-infrared cut filter glass of the present invention, even when the near-infrared cut filter glass is directly sealed on the package as a window glass for a solid-state imaging device package, the package can be quickly formed using an ultraviolet curable adhesive. Can be pasted together.

  DESCRIPTION OF SYMBOLS 1 ... Near-infrared cut filter glass (Embodiment 1), 2 ... Step part, 3 ... Thin part (peripheral part), 4 ... Side surface, 5 ... 1st light transmission surface, 6 ... 2nd light transmission surface (optical effective part) ), 7 ... UV curable adhesive, 8 ... Solid-state imaging device, 9 ... Package, 10 ... Plate glass, 11 ... Groove, 12 ... Grinding wheel, 13 ... Groove center line, 14 ... Taper, 21 ... Near Infrared cut filter glass (Embodiment 2), 22 ... Optically effective part, 23 ... Peripheral part, 24 ... Glass rod, 25 ... Glass plate, 26 ... Near infrared cut filter glass rod, 27 ... Cutting device, 28 ... Flat plate Glass, 29 ... Stretching base material, 31 ... Heater, 33 ... Base material support part, 34 ... Base material stretching part, 35 ... Outer diameter (thickness) control part, 41 ... Near-infrared cut filter glass (Embodiment 3) ), 42 ... CuO-containing glass, 43 ... UV transmissive glass, 100 ... solid Image sensor device.

Claims (12)

  A plate-like near-infrared cut filter glass made of a fluorophosphate-based glass containing CuO or a phosphate-based glass containing CuO, which is adjacent to the outer periphery of the optically effective portion that transmits light and the optically effective portion The near-infrared cut filter glass characterized by having a peripheral edge part, and the ultraviolet-ray transmittance of the said peripheral part is higher than the ultraviolet transmittance of the said optical effective part.   The peripheral portion surrounds the outer periphery of the optically effective portion in a frame shape, and the plate thickness of the peripheral portion is formed thinner than the plate thickness of the optically effective portion. The near infrared cut filter glass described.   The near-infrared cut filter glass according to claim 1 or 2, wherein the near-infrared cut filter glass is used for sealing in an opening of a package of a solid-state imaging device, and the peripheral edge portion is used as a sealing portion.   The near-infrared cut filter glass according to claim 2 or 3, wherein the peripheral portion is a ground surface formed by grinding.   The glass constituting the near-infrared cut filter glass contains 0.1 to 5 parts by mass of CuO on the basis of 100 parts by mass of the basic glass made of fluorophosphate glass or phosphate glass. The near-infrared cut filter glass according to any one of claims 1 to 4, wherein A method for producing a plate-shaped near-infrared cut filter glass comprising a fluorophosphate-based glass containing CuO or a phosphate-based glass containing CuO and sealed in a package of a solid-state imaging device. The manufacturing method of the near-infrared cut filter glass characterized by having these processes.
(1) melting a fluorophosphate glass containing CuO or a phosphate glass containing CuO to obtain a plate-like glass;
(2) a step of optically polishing both surfaces of the plate-like glass;
(3) a step of forming lattice-like grooves on one side of the plate-like glass;
(4) A step of cutting and separating the plate-like glass along the center line of the formed groove.   Next to the step of optically polishing both surfaces of the plate-like glass, the method includes a step of forming an optical thin film having an ultraviolet-cut function on one surface of the plate-like glass, and a lattice-like groove is formed on one surface of the plate-like glass. The method for producing a near-infrared cut filter glass according to claim 6, wherein in the forming step, lattice-like grooves are formed on the surface on which the optical thin film is formed.   The method for producing a near-infrared cut filter glass according to claim 6 or 7, wherein the step of forming lattice-like grooves on one side of the plate-like glass is performed by grinding.   3. The near-infrared cut filter glass according to claim 1, wherein the glass composition of the peripheral edge portion has less CuO content or no CuO content than the glass composition of the optically effective portion.   The near-infrared cut filter glass according to claim 9, wherein the near-infrared cut filter glass is used for sealing in an opening of a package of a solid-state imaging device, and the peripheral edge is used as a sealing portion.   The near-infrared cut filter glass is integrated with a frame-like glass containing less CuO or less CuO than the glass constituting the optically effective part on the outer periphery of the glass containing CuO and constituting the optically effective part. The near-infrared cut filter glass according to claim 9 or 10, wherein A frame-like glass having a CuO content less than that of the glass constituting the optically effective part or not containing CuO is integrated on the outer periphery of the plate-like glass that contains the optically effective part that contains CuO and transmits light. It is a manufacturing method of near-infrared cut filter glass, Comprising: The manufacturing method of the near-infrared cut filter glass characterized by having the following processes.
(1) Melting infrared absorbing glass containing CuO, creating a square columnar glass rod, and optically polishing the four outer surfaces;
(2) a step of melting and molding a glass having a CuO content less than that of the infrared absorbing glass or not containing CuO to form a glass plate, and optically polishing at least two adjacent surfaces;
(3) A step of creating a base material surrounding the four outer peripheral surfaces of the glass rod by bonding the polished surfaces of the glass plate to the polished surfaces of the square columnar glass rod,
(4) a step of heating and stretching the base material to a predetermined dimension;
(5) a step of cutting the base material that has been heat-stretched into a flat glass by cutting it in a direction perpendicular to the stretching axis;
(6) A step of optically polishing both surfaces of the flat glass.

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