JP7484712B2 - Composite member and molding die, manufacturing method of composite member, molding method of glass material, manufacturing method of optical element, manufacturing method of optical system, and manufacturing method of imaging device - Google Patents

Description

The present invention relates to a composite member including a glass member and a substrate, a molding die using the composite member, a method for manufacturing a composite member, a method for molding a glass material, an optical element, an optical system, and an imaging device.

In order to suppress deformation of the glass material during molding, materials with high Young's modulus, such as metals, cemented carbide, and ceramics, are used as the shape material of the mold for glass mold press molding (hereinafter referred to as press molding). However, in general, the harder the material, the longer it takes to process the mold.

If a material with good workability such as glass is used as the shape material of the molding die, the processing time of the molding die can be shortened. Glass can be processed into glass processed products of various shapes by various processing methods such as etching, cutting, polishing, and press molding. Such glass processed products can form a mold for imprinting UV curable resin. Patent Document 1 also describes an example of press molding a glass material using a molding die made of glass.

However, the Young's modulus of glass is smaller than that of metals, cemented carbide, ceramics, etc. Therefore, the deformation of the glass material during molding (deformation from the desired shape) is greater than when a molding die made of metals, cemented carbide, ceramics, etc. is used.

Patent Document 2 describes a molding die in which crystallized glass is disposed as a glass member on a substrate of high speed steel.

Patent Document 3 describes a composite member (a mold for press molding a glass material) made of a glass member and a substrate.

Non-Patent Document 1 describes a method for evaluating warpage of a laminate. Non-Patent Document 2 describes evaluation of the shape of a molded spherical lens when mold press molding of a spherical lens is performed using S-BSL7, which is a compatible material of BK-7 glass, as a glass material and a cemented carbide die.

Japan Patent Publication No. 2-1780 Japanese Patent Publication No. 2003-26429 Japanese Patent Publication No. 2002-348130

Naotoshi Yamashina, "Special 5: Mechanism of Warping in Copper-Clad Laminates," Abstracts of a Discussion Meeting, Japan Plastics Industry Association, 1985, Vol. 35, pp. 125-128 Hiroaki Ito et al., "Evaluation of Optimal Molding Conditions for Glass Lens Mold Press," Transactions of the Japan Society of Mechanical Engineers (Series A), November 2013, Vol. 79, No. 807, pp. 131-135

When forming a molding die including a glass member and a substrate, the molding die may be distorted due to thermal stress generated during bonding of the glass member and the substrate. In general, press molding of glass materials is performed at high temperatures such as 600°C. For example, when the glass member and the substrate are bonded at 800 to 1000°C, which is higher than the molding temperature, large thermal stress occurs when the temperature returns to room temperature. Thermal stress increases the possibility of breakage of the glass member. Thermal stress also increases the possibility of deformation of the glass member.

An object of the present invention is to reduce thermal deformation occurring in a composite member including a glass member and a substrate.

The composite member according to the present invention is a composite member including a glass member which is a molded portion, and a substrate supporting the glass member, and is characterized in that, when the thickness of the glass member is Hm, the Young's modulus of the glass member is Em, the linear expansion coefficient of the glass member is αm, the width of the glass member is W, the thickness of the substrate is Hs, the Young's modulus of the substrate is Es, and the linear expansion coefficient of the substrate is αs, and the warpage ΔH of the glass member is defined by the following formula, when the temperature difference ΔT between the temperature at which the warpage of the glass member is 0 and room temperature is 1000° C. is less than 0.004 mm.
ΔH=(1/|K|)-√{(1/K) ² -(W/2) ² }
(In the formula,
K = (A x F - B x D) / (A x C - B ² )
A = Es x Hs + Em x Hm
B = (1/2) x [Es x Hs ² + Em x {(Hs + Hm) ² - Hs ² }]
C = (1/3) x [Es x Hs ³ + Em x {(Hs + Hm) ³ - Hs ³ }]
D = ΔT × {Es × αs × Hs + Em × αm × Hm}
F = (ΔT/2) x [Es x αs x ^Hs2 + Em x αm x {(Hs + Hm) ² - ^Hs2 }]

The molding die according to the present invention is characterized in that it includes two mold members disposed opposite to each other, and at least one of the two mold members is the above-mentioned composite member.

The method for manufacturing a composite member according to the present invention is a method for manufacturing a composite member by joining a glass member, which is a formed part, to a substrate supporting the glass member to produce a composite member, and is characterized in that, when the thickness of the glass member is Hm, the Young's modulus of the glass member is Em, the linear expansion coefficient of the glass member is αm, the width of the glass member is W, the thickness of the substrate is Hs, the Young's modulus of the substrate is Es, and the linear expansion coefficient of the substrate is αs, and the warpage ΔH of the glass member is defined by the following formula, the glass member and the substrate are selected and joined together such that when the temperature difference ΔT between the temperature at which the warpage of the glass member is 0 and room temperature is 1000° C., the warpage ΔH of the glass member is less than 0.004 mm.
ΔH=(1/|K|)-√{(1/K) ² -(W/2) ² }
(In the formula,
K = (A x F - B x D) / (A x C - B ² )
A = Es x Hs + Em x Hm
B = (1/2) x [Es x ^Hs2 + Em x {(Hs + Hm) ² - ^Hs2 }]
C = (1/3) x [Es x Hs ³ + Em x {(Hs + Hm) ³ - Hs ³ }]
D = ΔT × {Es × αs × Hs + Em × αm × Hm}
F = (ΔT/2) x [Es x αs x ^Hs2 + Em x αm x {(Hs + Hm) ² - ^Hs2 }]

A method for forming a glass material according to the present invention is characterized in that a glass material is formed using the above-mentioned forming mold.

According to the present invention, it is possible to reduce thermal deformation occurring in a composite member including a glass member and a substrate.

FIG. 1 is a cross-sectional view that typically shows a mold member, which is an example of a composite member. FIG. 2 is a cross-sectional view showing a schematic diagram of another example of a mold member. FIG. 3 is an explanatory diagram showing the amount of displacement versus thickness Hm when the Young's modulus of glass is set to 70 GPa and a pressure of 1 MPa is applied to the surface of the glass. FIG. 4 is a cross-sectional view that illustrates a molding die that includes two mold members. FIG. 5 is a cross-sectional view showing a schematic diagram of another molding die. FIG. 6 is a cross-sectional view showing a typical state in which a glass material is molded using the mold member shown in FIG. FIG. 7 is an explanatory diagram showing the results of a simulation in which the thickness of the molded portion is changed.

1 is a cross-sectional view showing a mold member 10, which is an example of a composite member according to the present invention. The mold member 10 includes a molded portion 11 and a substrate 12. The molded portion 11 is a glass member made of glass. The molded portion 11 is bonded to the substrate 12. The bonding is performed, for example, by soldering or brazing via another member. The molded portion 11 and the substrate 12 may be directly bonded to each other by pressing them at high temperature, utilizing chemical bonds such as intermolecular forces or covalent bonds.

Materials having a high Young's modulus, such as metals, cemented carbide, ceramics, etc., can be used as the material of the substrate 12 to be joined to the molded portion 11. The Young's modulus of the substrate 12 is preferably 150 GPa or more, more preferably 300 GPa or more, and even more preferably 450 GPa or more.
There is no particular upper limit to the Young's modulus, but the range of Young's modulus for commonly available materials is equal to or less than 1100 GPa, which is the value of diamond.
The Young's modulus can be measured by a tensile test, a compression test, a torsion test, a resonance method, an ultrasonic pulse method, a pendulum method, etc. The measurement method is described in, for example, the following standards.
JIS R1602:1995 "Elastic modulus test method for fine ceramics"
JIS R1605:1995 "Test method for high temperature elastic modulus of fine ceramics"
JIS Z2201:1998 "Tensile test piece for metal materials"
JIS Z2241:2011 "Method of tensile testing of metal materials"
JIS G0567J:2012 "High temperature tensile test method for steel materials and heat-resistant alloys"
JIS Z2280:1993 "Method for testing Young's modulus at high temperatures for metallic materials"

In FIG. 1, W represents the width of the molded portion 11. Hs represents the thickness of the substrate. Hm represents the thickness of the molded portion 11. When the surface of the molded portion 11 is concave, the thickness of the molded portion 11 at the bottom of the recess can be used as Hm, and when the surface of the molded portion 11 is convex, the thickness of the molded portion 11 at the end of the convex can be used. The minimum width of the in-plane dimension can be used as the width W. When the end of the molded portion 11 is smoothly connected to the substrate 12, the average width of the part of the molded portion 11 whose height is Hm or less can be used as the width W. The average width W of the part of the molded portion 11 whose height is Hm or less can be calculated by W = Σ (Δh × W (h)) / Hm, where h is the height value. Here, W (h) represents the width of the molded portion 11 at the part whose height is h. In addition, the molded portion 11 has a curved surface for molding, and its depth is S.

The surface of the molded part 11 may be coated with an intermediate film or a protective film. An adhesive layer may be provided between the molded part 11 and the substrate 12. As the material for the intermediate film or the protective film, metals such as titanium, zirconium, niobium, hafnium, tantalum, chromium, molybdenum, tungsten, ruthenium, rhodium, iron, cobalt, nickel, palladium, rhenium, osmium, iridium, copper, silver, gold, platinum, and other metals, precious metals, and alloys, oxides, nitrides, oxynitrides, and carbides thereof may be used. In addition, silicon compounds such as silicon dioxide, silicon nitride, silicon oxynitride, and silicon carbide, carbon such as amorphous carbon and diamond-like carbon, and boron compounds may be used. The film may be multi-layered with a plurality of materials.

The surface shape of the molded portion 11 is not limited to an axially symmetric aspheric shape in a cross-sectional view, and may be a free curved surface, etc. Also, the surface of the molded portion 11 is not limited to a concave surface, and may be a convex surface.

1, the vertical cross-sectional shape of the substrate 12 is rectangular. However, the vertical cross-sectional shape of the substrate 12 is not limited to a rectangular shape. The horizontal cross-sectional shape of the substrate 12 is, for example, circular.

2 is a cross-sectional view showing another example of a mold member. The substrate 12 may have a flange as shown in FIG. 2(a). The substrate 12 may have a through hole or a screw hole in a part of the substrate. As shown in FIG. 2(b), the width of the molded portion 11 may be different from the width of the substrate 12. As shown in FIG. 2(c), the substrate 12 may have a recess in which the molded portion 11 is disposed.

The strain point of the glass used in the molding portion 11 is preferably 400°C or higher, more preferably 500°C or higher, and even more preferably 600°C or higher. The reason is that the molding temperature of most optical glasses is within the range of 400 to 600°C, and it is necessary that the shape can be sufficiently maintained during molding in this temperature range. The strain point can be measured by the method specified in JIS-R3103-2:2001, etc. There is no particular upper limit for the strain point of glass, but a commonly available material is quartz glass, which has a strain point of 1200°C or lower.

In order to create a bond that is durable at the above-mentioned glass forming temperature, it is preferable to form the bond at a temperature of 600° C. or higher. It is more preferable to form the bond at a temperature of 800° C. or higher. Even if the bond can be formed without warping at a temperature close to room temperature, it is necessary to consider warping that occurs when the temperature is raised to the glass forming temperature. The upper limit of the temperature for forming the bond is preferably equal to or lower than the strain point of the glass, and therefore the upper limit can be set to 1200° C. or lower.

Next, the deformation of the molded portion 11 will be considered.

Hereinafter, the general formula for warpage of a k-layer laminate described in Non-Patent Document 1 will be used for the study. In the following formula (1), E _k represents the elastic modulus of each layer. α _k represents the linear expansion coefficient of each layer. Z _k represents the position of the interface of each layer in the thickness direction from a reference coordinate that can be set at any position. t represents the temperature difference from the reference temperature. K represents the curvature K of the deformation of the laminate caused by the temperature difference t.

K = (A x F - B x D) / (A x C - B ² )
A = Σ{E _k × (Z _k - _{Z k-1} )}
B = (1/2) × Σ {E _k × {Z _k ² -Z _k-1 ² }}
C = (1/3) × Σ {E _k × (Z _k ³ −Z _k−1 ³ )}
D = t × Σ {E _k × α _k × (Z _k -Z _k-1 )}
F = (t/2) × Σ {E _k × α _k × (Z _k ² -Z _k-1 ² )}
... (1)

In the above formula (1), when the number of layers of the laminate is 2 and the amount of displacement (warping) in the thickness direction caused by the arc of curvature K is ΔH, ΔH is expressed by the following formula (2). In this embodiment, the two layers correspond to the molded portion 11 and the substrate 12.

ΔH=(1/|K|)-√{(1/K) ² -(W/2) ² } (2)

here,
K = (A x F - B x D) / (A x C - B ² )
A = Es x Hs + Em x Hm
B = (1/2) x [Es x ^Hs2 + Em x {(Hs + Hm) ² - ^Hs2 }]
C = (1/3) x [Es x Hs ³ + Em x {(Hs + Hm) ³ - Hs ³ }]
D = ΔT × {Es × αs × Hs + Em × αm × Hm}
F = (ΔT/2) × [Es × αs × Hs ² + Em × αm × {(Hs + Hm) ² - Hs ² }]
...(3)
It is.

In the above formula (3), Em represents the Young's modulus of the glass member which is the shaped portion 11. αm represents the linear expansion coefficient of the glass member which is the shaped portion 11. Es represents the Young's modulus of the substrate 12. αs represents the linear expansion coefficient of the substrate 12. ΔT represents the difference between the temperature when the mold member 10 is molded (the joining temperature when the shaped portion 11 and the substrate 12 are joined; in other words, the temperature when the warpage of the glass member is 0) and room temperature. Here, room temperature is a temperature in the range of 20 to 25°C, and 20°C unless otherwise specified below.

The units of Es and Em are [MPa], Hm and Hs are [mm], the unit of the linear expansion coefficient is [1/°C], the unit of ΔT is [°C], and the unit of ΔH is [mm].
The linear expansion coefficient can be measured using a thermomechanical analyzer (TMA). Alternatively, the following method according to the JIS standard may be used.
JIS Z2285:2003 Measurement method of linear expansion coefficient of metal materials JIS R1618:2002 Measurement method of thermal expansion of fine ceramics by thermomechanical analysis JIS R3251:1995 Measurement method of linear expansion coefficient of low expansion glass by laser interference method JIS R3102:1995 Test method of average linear expansion coefficient of glass

When using the above formula (2), it is preferable that W, Hs, and Hm are selected so that ΔH<0.004 is satisfied when ΔT=1000 ([° C.]). It is more preferable that W, Hs, and Hm are selected so that ΔH<0.002 is satisfied when ΔT=1000. It is even more preferable that W, Hs, and Hm are selected so that ΔH<0.001 is satisfied when ΔT=1000. It is even more preferable that W, Hs, and Hm are selected so that ΔH<0.0005 is satisfied when ΔT=1000. As can be seen from formula (2), the lower limit of ΔH is 0.

The reason why W, Hs, and Hm are preferably selected under the above conditions will be described later.

In this embodiment, the number of layers of the laminate (molded portion 11 and substrate 12) is 2. Therefore, the warpage is evaluated by the above formulas (2) and (3). In addition, when the molded portion 11 and substrate 12 are joined by soldering, brazing, etc., an adhesive layer is interposed between the molded portion 11 and substrate 12. However, when the adhesive layer is sufficiently thin compared with the molded portion 11 and substrate 12, the above formula (3) can be used as the adhesive layer has little influence. When it is determined that the influence of the adhesive layer cannot be ignored, that is, when it is determined that the number of layers is better to be 3, K may be calculated using the above formula (1) instead of the above formula (3). Whether or not the influence of the adhesive layer can be ignored is determined, for example, by formula (2) using the result of calculating K by the above formula (1). In addition, when an intermediate film or a protective film is coated on the surface of the molded portion 11, when it is determined that the influence of the intermediate film or the protective film cannot be ignored, K may be calculated using the above formula (1).

Table 1 shows the results of calculating the warpage using the above formula (2) for several laminates. As shown in Table 1, the value of the warpage ΔH can be reduced by using a base material 12 with a high Young's modulus Es, reducing the thickness Hm of the molded portion 11, and reducing the value of the width W of the molded portion 11. Note that ΔT=1000.

Referring to Table 1, the width W of the molded portion 11 is preferably 20 mm or less, more preferably 10 mm or less, and further preferably 5 mm or less. The width of the molded portion 11 may be any value greater than 0.

Reducing the difference between the linear expansion coefficient αm of the molded portion 11 and the linear expansion coefficient αs of the base material 12 also contributes to reducing the expansion difference due to temperature changes. The difference between the linear expansion coefficient αm of the molded portion 11 and the linear expansion coefficient αs of the base material 12 is 3×10^-6[1/°C] or less, and^-6[1/° C.] or less. It is preferable to use ceramics such as alumina, silicon nitride, silicon carbide, or cemented carbide as the material for the substrate 12, since the Young's modulus of the substrate can be increased. However, the linear expansion coefficient of these materials is 2.5 to 8.0×10 ^-6[1/° C.]. Therefore, it is preferable that the linear expansion coefficient of the glass material of the molded portion 11 is also in such a range. The lower limit of the difference in linear expansion coefficient is 0.

The thickness Hm of the molded portion 11 is preferably thin in order to reduce the amount of displacement during molding.

FIG. 3 shows the amount of displacement in the thickness direction versus thickness Hm when the Young's modulus of glass is set to 70 GPa and a pressure of 1 MPa is applied to the surface of the glass.

For example, in the case of aspherical lenses, shape defects of 100 nm or less can be problematic. It is preferable that the amount of displacement of the molded portion 11 in the thickness direction during pressure application is suppressed as much as possible, such as to 100 nm or less. Therefore, also referring to Table 1, the thickness Hm of the molded portion 11 is preferably 6 mm or less. It is more preferable that it is 3 mm or less. It is even more preferable that it is 1 mm or less. It is even more preferable that it is 0.5 mm or less. It is sufficient that Hm is a value greater than 0.

Based on the preferred values of the parameters (W, Hm, and αm, αs) described above, and also referring to Table 1 (particularly column [4]) and the comparative examples described later, the condition that the warpage ΔH of the molded portion 11 is less than 0.004 mm is derived. The thickness Hs of the substrate may be any value greater than 0. Furthermore, if the substrate is too thick, problems such as a large heat capacity during heating will occur, so Hs is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 20 mm or less.

The depth S of the molded portion 11 is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.75 mm or less. In this way, non-uniform deformation due to differences in glass thickness can be suppressed. The depth S of the molded portion 11 may be any value greater than 0.

Fig. 4 is a cross-sectional view showing a molding die including two mold members (first mold member 10a, second mold member 10b) arranged opposite each other. The molding die shown in Fig. 4 includes a first mold member 10a having a molding part 11a and a base material 12a made of glass, a second mold member 10b having a molding part 11b and a base material 12b made of glass, a guide member 21 provided to surround the first mold member 10a and the second mold member 10b to accommodate the first mold member 10a and the second mold member 10b, and an inner member 22. The first mold member 10a or the second mold member 10b is pressed to mold a glass material 23.

Both the first mold member 10a and the second mold member 10b are members produced based on the parameters of the preferred values described above. However, one of the two mold members may be a member produced based on the parameters of the preferred values described above. Also, one of the two mold members may be a mold member other than the composite member described above (i.e., a composite member including a glass member as a molded part and a substrate supporting the glass member). For example, one of the two mold members may be a single member, or a composite member including a molded part made of a material other than a glass material with respect to the substrate. As such a mold member made of a single material or a molded part made of a material other than a glass material, metal, cemented carbide, ceramic, etc. can be used. Also, the surface shapes of the molded parts in the opposing mold members can be freely designed. That is, the surface shape of each molded part is not limited to an axially symmetric aspheric shape in a cross-sectional view, and may be a concave, convex, wavy free-form surface shape, or flat. Also, the opposing mold members do not have to have the same surface shape, and for example, the surface shape of one molded part may be a concave curved shape, and the surface shape of the other molded part may be a convex or flat shape. However, the combination of the surface shapes of the molded parts of the opposing mold members is not limited to this. In addition, when one of the two opposing mold members is not the above-mentioned composite member, the surface of the molded part included in the mold member may be covered with the above-mentioned intermediate film or protective film. Alternatively, the surface of the molded part included in the mold member may be subjected to a release treatment such as applying a release agent.

The inner member 22 has, for example, a ring-shaped structure. The inner member 22 is used to determine the outer shape of the glass material 23 during molding. If it is not necessary to determine the outer shape, the inner member 22 may be omitted.

The guide material 21 and the inner material 22 can be made of glass, metal, ceramics, cemented carbide, or other materials. In addition, when the linear expansion coefficients of the first mold member 10a, the second mold member 10b, the inner material 22, and the guide material 21 are α10a, α10b, α22, and α21, respectively, α10a≧α10b≧α21 or α22≧α21 may be satisfied. In such a case, the gap between the members can be narrowed during thermal expansion, and for example, eccentricity between the first mold member 10a and the second mold member 10b can be suppressed.

4 illustrates a molding die having a configuration in which a pair of the first mold member 10a and the second mold member 10b are arranged inside the guide member 21, but the molding die is not limited to such a structure. For example, the molding die may be configured such that a plurality of through holes are provided in the guide member 21 and a plurality of pairs of the first mold member 10a and the second mold member 10b are arranged therein.

Fig. 5 is a cross-sectional view showing another molding die. The molding die shown in Fig. 5 includes a first mold member 10c (composite member) having a molding part 11c and a base material 12c made of glass, a second mold member 10d (composite member) having a molding part 11d and a base material 12d made of glass, a guide member 31, an inner member 32, and a pin member 33. The first mold member 10c or the second mold member 10d is pressurized to mold a glass material 23.

In the example shown in FIG. 5, the first mold member 10c and the second mold member 10d each have a plurality of molding parts 11c, 11d made of glass. In addition, the first mold member 10c and the second mold member 10d are provided with through holes for passing the pin members 33. The pin members 33 suppress the rotation of the first mold member 10c and the second mold member 10d. A plurality of through holes for passing the pin members 33 may be provided. When a plurality of through holes are provided, a plurality of pin members 33 can be installed, and the rotation of the first mold member 10c and the second mold member 10d is suppressed by two or more pin members 33. Therefore, the guide material 31 may not be required.

Both the first mold member 10c and the second mold member 10d are members produced based on the parameters of the preferred values described above. However, one of the two mold members may be a member produced based on the parameters of the preferred values described above. For example, when the formula (2) is calculated using the width and thickness of each molded portion for the configuration shown in FIG. 5, it is preferable that ΔH<0.004 when ΔT=1000, more preferably ΔH<0.002 when ΔT=1000, even more preferably ΔH<0.001 when ΔT=1000, and even more preferably ΔH<0.0005 when ΔT=1000. Note that the number of molded portions included in one mold member is different from the example of FIG. 4, and in this example, one of the two mold members may be a mold member other than the composite member described above (for example, a composite member including a molded portion made of a material other than a glass material for a mold member made of a single material or a base material as described above), as in the example of FIG. 4. Note that, as can be seen from the formula (2), the lower limit of ΔH is 0.

The inner member 32 is formed, for example, in a plate shape with a plurality of through holes. The inner member 32 can be used to determine the outer shape of the glass material 23 during molding. If it is not necessary to determine the outer shape of the glass material 23, the inner member 32 may be omitted.

Materials such as glass, metal, ceramics, and cemented carbide can be used as the guide material 31, the inner member 32, and the pin member 33. In addition, when the linear expansion coefficients of the first mold member 10c, the second mold member 10d, the inner member 32, the guide material 31, and the pin member 33 are α10c, α10d, α32, α31, and α33, α10c ≧ α10d ≧ α31, or α33 ≧ α10c ≧ α10d, or α32 ≧ α31, or α33 ≧ α32 may be satisfied.

Next, a method for manufacturing the mold member 10 or the first mold member 10c (or the second mold member 10d) will be described using the mold member 10 shown in FIG. 1 or the molding die shown in FIG. 5 as an example.

For example, a mold having a shape corresponding to the outer shape of the molded portion 11 or the molded portion 11c (or the molded portion 11d) is prepared. The molded portion 11 or the molded portion 11c (or the molded portion 11d) is produced using such a mold.

Also, the substrate 12 or substrate 12c (or substrate 12d) is prepared. The thickness Hm and width W of the molded portion 11 or molded portion 11c (or molded portion 11d), the parameters of the material of the molded portion 11 or molded portion 11c (or molded portion 11d) (Young's modulus and linear expansion coefficient), and the parameters of the material of the substrate 12 or substrate 12c (or substrate 12d) are selected so that ΔH calculated using the above formula (2) is 0.004 mm or less. Note that ΔT is 1000° C. Also, for example, a glass member with a strain point of 600° C. or more is used as the substrate 12 or substrate 12c (or substrate 12d).

Next, in a high-temperature environment (e.g., 800° C.), the molded portion 11 or the molded portion 11c (or the molded portion 11d) is bonded to the base material 12 or the base material 12c (or the base material 12d). The bonding method is as described above. The high-temperature environment is a temperature environment equal to or higher than the temperature at which the glass material 23 is molded.

In this embodiment, the mold member for molding the glass material 23 is taken as an example, but the use of the mold member is not limited to glass molding. The mold member can also be used as a mold for molding resin materials such as thermosetting resin and UV curing resin. In addition, the production of the molded portion 11 and the bonding of the molded portion 11 and the base material 12 may be performed simultaneously in a high temperature environment.

Next, an example of a method for molding a glass material using the molding die of this embodiment will be described, taking as an example a case in which the molding die shown in FIG.

The glass material 23 is placed on the second mold member 10b. Then, the first mold member 10a is lowered to a predetermined position. Next, the composite member (the first mold member 10a and the second mold member 10b) is heated to a temperature during press molding (e.g., 600°C), and the first mold member 10a is pressed. Then, the composite member and the molded glass material 23 are slowly cooled, the first mold member 10a is raised, and the molded glass material 23 is taken out.

It is to be noted that, instead of lowering the first mold member 10a, the second mold member 10b may be raised. Also, although the case where the molding die shown in Fig. 4 is used has been described, the glass material 23 is molded in a similar manner when the molding die shown in Fig. 5 is used.

(Example)
An example using the mold member 10 shown in Fig. 1 will be described below. In this example, the molded portion 11 is a glass member with a Young's modulus of 80 GPa and a linear expansion coefficient of 3.2 x ^10-6 [1/°C]. The thickness Hm of the molded portion 11 is 0.13 mm. The width W of the molded portion 11 is 2.3 mm. The surface shape of the molded portion 11 is a sphere with a radius of curvature of 1.13 mm. The depth S of the sphere is 0.37 mm.

The substrate 12 is made of a cemented carbide having a Young's modulus of 600 GPa and a linear expansion coefficient of 5.5×10 ⁻⁶ [1/° C.]. The substrate 12 has a thickness Hs of 5 mm.

When ΔH was calculated using the above formula (2) when ΔT=1000, it was found to be ΔH=8 nm.

6 is a cross-sectional view showing a state where a glass material 23 is molded using the mold member shown in FIG. 1. In FIG. 6(a), a second mold member 10f having a molded portion 11f and a base material 12f made of glass is shown as a mold member. In FIG. 6(b), a first mold member 10e having a molded portion 11e and a base material 12e made of glass is shown as an opposing mold member. The surface shape of the molded portion 11e is an aspheric surface that is approximated by a sphere with a radius of curvature of 1.76 mm, and is convex toward the outside. As shown in FIG. 6(b), a glass molded product 24 is obtained.

Using S-BSL7 as the glass material 23, calculations were carried out using the finite element method to simulate molding of the glass material 23 using the mold members shown in Fig. 6. With reference to Non-Patent Document 2, the Prony coefficient of rigidity and relaxation time used in the calculations using the finite element method were set as shown in Table 2. The Poisson's ratio of the glass was set to 0.205.

After the simulation molding using the finite element method, the amount of displacement in the thickness direction of the molded portion 11f after molding was calculated. It was confirmed that the average amount of displacement was 8 nm, which was sufficiently small, even when calculated using the finite element method.

Furthermore, a simulation was performed in which the length (thickness) of the molded portion 11f was changed. The simulation results are shown in Fig. 7. As shown in Fig. 7, it was confirmed that the amount of displacement decreased as the molded portion 11f became thinner.

Comparative Example
A comparative example using the mold member 10 shown in FIG. 1 will be described. The molded portion 11 is a glass member having a Young's modulus of 70 GPa and a linear expansion coefficient of 4.0×10 ⁻⁶ [1/° C.]. The base material 12 is a cemented carbide having a Young's modulus of 500 GPa and a linear expansion coefficient of 5.5×10 ⁻⁶ [1/° C.]. The thickness Hs of the base material 12 is 10 mm. The thickness Hm of the molded portion 11 is 10 mm. The width W of the molded portion 11 is 20 mm. The values of these parameters correspond to the values listed in column [4] in Table 1.

When ΔH is calculated using the above formula (2) when ΔT is 1000, it is found to be ΔH = 0.0042 mm. With such a value, the shape deformation of the mold member due to joining becomes large, and it is considered that this value is not suitable for use as a mold member.

The optical element molded by the molding method of the glass material 23 of this embodiment is a glass lens, but is not limited thereto and may be a lens made of a light-transmitting material, for example, a light-transmitting resin. Furthermore, the shape of the glass lens is not limited, and may be aspherical, spherical, or flat.

The optical element can be applied (eg, incorporated) into a variety of optical systems.

The optical system may include, for example, lenses that cooperate with the above optical elements, optical filters such as anti-reflection films and bandpass filters, cover glass, apertures, etc. However, these are merely examples, and the application of the above optical elements is not limited to these.

It is also envisioned that the above optical element will be applied to an imaging device such as a camera.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2018-125019 filed on June 29, 2018, the contents of which are incorporated herein by reference.

REFERENCE SIGNS LIST 10 Mold member 11 Molding portion 12 Base material 10a, 10c, 10e First mold member 10b, 10d, 10f Second mold member 11a, 11c, 11e First molding portion 11b, 11d, 11f Second base material 12a, 12c, 12e First molding portion 12b, 12d, 12f Second base material 21 Guide member 22 Internal member 23 Glass material 31 Guide member 32 Internal member 33 Pin member

Claims (15)

A composite member including a glass member that is a molded portion and a substrate that supports the glass member,
the surface of the glass member is concave or convex;
In a longitudinal cross section of the substrate, a joining surface between the glass member and the substrate and an opposite surface of the substrate facing the joining surface are parallel to each other (however, in a case where the substrate has a through hole and/or a screw hole, the joining surface and the opposite surface exclude a surface formed by the through hole and/or the screw hole).
the base material has a maximum distance between the joining surface and the opposite surface in a thickness direction of the base material,
When the thickness of the glass member is represented by Hm, the Young's modulus of the glass member is represented by Em, the linear expansion coefficient of the glass member is represented by αm, the width of the glass member is represented by W, the thickness of the substrate is represented by Hs, the Young's modulus of the substrate is represented by Es, and the linear expansion coefficient of the substrate is represented by αs, and the warp ΔH of the glass member is defined by the following formula:
A composite member, wherein when a temperature difference ΔT between a temperature at which the warp of the glass member is 0 and room temperature is 1000° C., the warp ΔH of the glass member is less than 0.004 mm.
ΔH=(1/|K|)-√{(1/K) ² -(W/2) ² }
(In the formula,
K = (A x F - B x D) / (A x C - B ² )
A = Es x Hs + Em x Hm
B = (1/2) x [Es x Hs ² + Em x {(Hs + Hm) ² - Hs ² }]
C = (1/3) x [Es x Hs ³ + Em x {(Hs + Hm) ³ - Hs ³ }]
D = ΔT × {Es × αs × Hs + Em × αm × Hm}
F = (ΔT/2) x [Es x αs x ^Hs2 + Em x αm x {(Hs + Hm) ² - ^Hs2 }]
Here, the thickness Hm of the glass member is the thickness of the glass member at the bottom of the recess when the surface of the glass member is concave, and is the thickness of the shaped portion at the end of the convex portion when the surface of the glass member is convex,
The width W of the glass member is the minimum width of the in-plane dimension of the joining surface,
The thickness Hs of the substrate is the distance between the joining surface and the opposite surface of the substrate (however, if the substrate has a through hole and/or a screw hole, the joining surface and the opposite surface exclude the surfaces formed by the through hole and/or the screw hole). The thickness Hm of the glass member is 6 mm or less.
The composite member according to claim 1 . The thickness Hm of the glass member is 1 mm or less.
The composite member according to claim 2. The thickness Hm of the glass member is 0.5 mm or less.
The composite member according to claim 3. The Young's modulus Es of the substrate is 150 GPa or more;
A composite member according to any one of claims 1 to 4. a difference between the linear expansion coefficient αm of the glass member and the linear expansion coefficient αs of the base material is 3×10 ⁻⁶ (1/° C.) or less;
A composite member according to any one of claims 1 to 5. A molding die including two mold members disposed opposite each other,
At least one of the two mold members is a composite member according to any one of claims 1 to 6.
Mould for forming. A guide member is provided to accommodate the two mold members.
The mold according to claim 7. The composite member includes a plurality of the glass members bonded to one of the substrates.
The molding die according to claim 7 or 8. A method for producing a composite member, comprising bonding a glass member, which is a formed portion, to a substrate supporting the glass member, the method comprising the steps of:
the surface of the glass member is concave or convex;
In a longitudinal cross section of the substrate, a joining surface between the glass member and the substrate and an opposite surface of the substrate facing the joining surface are parallel to each other (however, in a case where the substrate has a through hole and/or a screw hole, the joining surface and the opposite surface exclude a surface formed by the through hole and/or the screw hole).
the base material has a maximum distance between the joining surface and the opposite surface in a thickness direction of the base material,
the thickness of the glass member is Hm, the Young's modulus of the glass member is Em, the linear expansion coefficient of the glass member is αm, the width of the glass member is W, the thickness of the substrate is Hs, the Young's modulus of the substrate is Es, and the linear expansion coefficient of the substrate is αs; when a warp ΔH of the glass member is defined by the following formula, the glass member and the substrate are selected such that when a temperature difference ΔT between a temperature at which the warp of the glass member is zero and room temperature is 1000° C., the warp ΔH of the glass member is less than 0.004 mm;
bonding the glass member and the base material;
A method for manufacturing a composite component.
ΔH=(1/|K|)-√{(1/K) ² -(W/2) ² }
(In the formula,
K = (A x F - B x D) / (A x C - B ² )
A = Es x Hs + Em x Hm
B = (1/2) x [Es x ^Hs2 + Em x {(Hs + Hm) ² - ^Hs2 }]
C = (1/3) x [Es x Hs ³ + Em x {(Hs + Hm) ³ - Hs ³ }]
D = ΔT × {Es × αs × Hs + Em × αm × Hm}
F = (ΔT/2) x [Es x αs x ^Hs2 + Em x αm x {(Hs + Hm) ² - ^Hs2 }]
Here, the thickness Hm of the glass member is the thickness of the glass member at the bottom of the recess when the surface of the glass member is concave, and is the thickness of the shaped portion at the end of the convex portion when the surface of the glass member is convex,
The width W of the glass member is the minimum width of the in-plane dimension of the joining surface,
The thickness Hs of the substrate is the distance between the joining surface and the opposite surface of the substrate (however, if the substrate has a through hole and/or a screw hole, the joining surface and the opposite surface exclude the surfaces formed by the through hole and/or the screw hole). The strain point of the glass member is 600° C. or higher.
A method for producing a composite member according to claim 10. A glass material is molded using the molding die according to any one of claims 7 to 9.
A method for forming glass materials. A method for manufacturing an optical element, comprising molding a glass material using the molding die according to any one of claims 7 to 9 to produce an optical element. A method for manufacturing an optical system, comprising: molding a glass material using a molding die according to any one of claims 7 to 9 to obtain an optical element; and manufacturing an optical system using the optical element. A method for manufacturing an imaging device, comprising: forming a glass material using a molding die according to any one of claims 7 to 9 to obtain an optical element; and manufacturing an imaging device using the optical element.

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