JP2007119280A - Method for forming glass optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a method for forming a glass optical element capable of securing the optical property of an optical element having optical surfaces of high precision and improving the yield by improving its productivity. <P>SOLUTION: The method for forming a glass optical element contains a first process where a difference between a pair of optical surface shapes of a glass optical element formed by using a pair of molds having an optical forming surface processed to have a shape by which an optical surface shape based on the designed value of a glass lens 15 is transferred and an optical surface shape specified based on the designed value is measured, a second process where the optical forming surface of one of the pair of molds 2 is processed based on the measured value so as to make a distance between the optical surfaces in the direction parallel to the optical axis of a pair of optical surfaces 15a, 15b the same distance as a distance specified based on the designed value, and a third process where a glass optical element is formed by the pair of molds, i.e. the processed mold and the other mold 3. By this method, the optical property of the optical element is secured and the productivity is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a glass optical element molding method in which a glass optical element is molded by pressing a glass material heat-softened by a pair of molds.

  In recent years, an optical element that is a glass lens has been required to have a highly accurate optical surface shape, for example, due to an increase in the number of pixels of an imaging element such as a digital camera. In addition, with the miniaturization of camera housings, there is an increasing demand for optical elements having aspherical high-precision concave lens surfaces.

  Such an optical element requiring high precision is made of glass by a molding die having a mirror-finished molding surface as described in the optical element molding methods of Patent Document 1 and Patent Document 2, for example. It is manufactured by an optical element molding apparatus that press-molds an optical material that is a material in a heat-softened state.

  In the optical element molding method described in Patent Document 1, in order to maintain the accuracy of transferring the optical surface of the high-precision optical element by the optical molding surface of the mold, the optical element after molding that has been softened by heating is cooled. A technique for slowly cooling at a rate of 10 ° C./min is disclosed.

Further, in the optical element molding method described in Patent Document 2, the molding die is processed into a shape that cancels the habit of the optical surface (optical function surface) that occurs during the molding of the optical element. Techniques for setting various molding conditions are disclosed.
JP-A-5-2185 JP-A-6-72726

  However, in the technique of the above-mentioned Patent Document 1, there is a problem that if the cooling rate of the optical element is slowed down, the manufacturing cycle time becomes long and the productivity is inferior. Further, in the molding of an optical surface that requires high accuracy such as a concave lens, there are cases where transfer accuracy by a molding die cannot be obtained only by slowing the cooling rate.

  Moreover, in the technique of patent document 2, the defect which arises by the curvature of the optical element etc. which generate | occur | produce when releasing an optical element from the shaping | molding die processed into the shape which cancels the habit of an optical surface with respect to an optical element shaping | molding apparatus. It is necessary to set various molding conditions to avoid this many times. Therefore, the optical element molding method of Patent Document 2 requires labor for setting various molding conditions, and requires a processing time of the mold according to the molding conditions, which causes a problem of yield reduction. is there.

  Accordingly, the present invention has been made in view of the above circumstances, and is a glass optical element in which the yield is improved by ensuring the optical performance of an optical element having a highly accurate optical surface and improving the productivity. An object is to provide a forming method.

  As described above, an optical element that is pressed to obtain a necessary optical surface does not necessarily obtain a desired optical surface, and has an error from the designed ideal optical surface. In the present invention, the inter-surface dimension at an arbitrary radial position from the center of the optical axis of the pair of optical surfaces pressed and molded without bringing the optical surface having this error directly close to the ideal design surface is designed. The optical performance of the pair of optical surfaces is ensured by approaching the inter-surface dimension at the arbitrary radius position from the center of the optical axis. And although all the optical elements having error optical surfaces obtained by such means do not optically satisfy the performance, there is a fact that at least some of these optical elements can be put to practical use. .

  Therefore, in the first glass optical element molding method of the present invention, a glass material is pressed by pressing a glass material with a pair of molds, and an optical surface shape based on the design value of the glass optical element can be transferred. Measuring a difference between the pair of optical surface shapes of the glass optical element molded using the pair of molds having the optical molding surface processed into a shape and the optical surface shape determined based on the design value. And the distance between the optical surfaces along an axis parallel to the optical axis at any point in the radial direction from the optical axis on the pair of optical surfaces of the glass optical element based on the measured and the measured difference To the same distance as the distance determined based on the design value, a second step of processing the optical molding surface of the pair of one mold, the one mold processed, and the pair of molds With the other mold of the above glass light Characterized in that it comprises a third step of molding the element.

In the second glass optical element molding method of the present invention, the glass optical element is molded by pressing a glass material with a pair of molds, and from an optical axis at an arbitrary point on the pair of optical surfaces of the glass optical element. the distance between the r, when representing the distance D ₀ parallel to the optical axis between the pair of optical surfaces in the design values of the optical glass element by the following formula (1), the pair of the molded glass optical element of the distance D ₁ parallel to the optical axis between the optical surface and the following formula (2), as follows (3) the difference is represented by [Delta] d (r) is substantially zero {Δd (r) ≒ 0} A glass element molding method comprising: adjusting at least one of the pair of molds at the time of processing and molding, and pressing the glass optical element with the pair of molds.

D ₀ = f ₀ (r) (1)
D ₁ = f ₁ (r) (2)
D ₁ −D ₀ = f ₁ (r) −f ₀ (r) = Δd (r) (3)
However, f ₀ (r) and f ₁ (r) are functional expressions relating to the distance r.

Moreover, the 3rd glass optical element shaping | molding method of this invention presses a glass raw material with a pair of type | mold, and differs from 1st optical surface which has 1st effective diameter Z1, and this 1st effective diameter Z1. A glass optical element composed of a second optical surface having a second effective diameter Z2 is molded, and the first optical surface at the first distance r1 in the radial direction from the optical axis in the designed glass optical element. A first point connecting the first arbitrary point above and a second point at a second distance r2 derived from the following equation (1) in the radial direction from the optical axis on the second optical surface. A distance L ₀ (r1) of 1 and an arbitrary first point at the first distance r1 in the radial direction from the optical axis on the first optical surface in the glass optical element after molding; At the second distance r2 derived from the following formula (1) in the radial direction from the optical axis on the second optical surface: As the distance _L 1 connecting the second point (r1) Tokara formula (2) the difference [Delta] L (r1) represented by becomes substantially zero {ΔL (r1) ≒ 0} , the pair of dies A method for molding a glass optical element, characterized in that at least one of the optical surfaces is processed and mold-to-mold adjustment is performed, and the glass optical element is press-molded by the pair of molds.

Z2 × r1 / Z1 = r2 (1)
L ₀ (r1) −L ₁ (r1) = ΔL (r1) (2)

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring the optical performance of the optical element which has a highly accurate optical surface, productivity can improve and the glass optical element shaping | molding method which improves a yield is realizable.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 to 12 relate to the first embodiment of the glass optical element molding method of the present invention, and FIG. 1 is a sectional view showing the inside of the optical element molding apparatus. 2 is a cross-sectional view showing a pair of molds, a sleeve, and a glass material of the optical element molding apparatus of FIG. FIG. 3 is a cross-sectional view of the glass optical element after molding. FIG. 4 is an operation flowchart of the optical element molding apparatus for molding a glass lens from a glass material. FIG. 5 is an operation flowchart for forming an optical element that approximates a design value so as to satisfy the optical performance. FIG. 6 is a function graph showing the shape of the concave lens surface in one section of the glass optical element of FIG. 3 of one embodiment. FIG. 7 is a function graph showing the shape of the convex lens surface in one section of the glass optical element of FIG. FIG. 8 is a function graph in which the functions shown in FIGS. 6 and 7 are superimposed. FIG. 9 is a function graph obtained by synthesizing the functions shown in FIGS. 6 and 7. FIG. 10 is a diagram showing a state in which the cross section of the glass lens after molding is superimposed on the cross section of the upper mold, FIG. 10 (a) illustrates one means, and FIG. 10 (b) illustrates the other means. It is a figure for demonstrating. FIG. 11 is a function graph showing the shape of the concave lens surface in one cross section of the glass optical element of one example formed by the upper convex molding surface after processing. FIG. 12 is a function graph in which the functions shown in FIGS. 7 and 9 are synthesized.

  The optical element molding apparatus 1 according to this embodiment shown in FIGS. 1 and 2 heats and softens the glass material 15A, which is an optical material, presses it with a pair of molds, and opens the pair of molds after cooling. This is an apparatus for manufacturing a glass lens 15 which is a glass optical element having a desired surface shape. The optical element molding apparatus 1 includes, as main components, a pair of upper mold 2 and lower mold 3, an upper shaft 4 that supports the upper mold 2, and a lower mold 3 that supports the lower mold 3. A shaft 5, a sleeve 6 that covers the upper die 2 and the lower die 3, an elevating base body 7 that holds the upper shaft 4 in an up and down direction in a sealed state, and an integral body with the elevating base body 7 A fixed quartz tube 8, an upper cooling plate 9 provided on the upper part of the elevating base body 7, a base plate 10 on which the lower shaft 5 is placed, and a lower part of the base plate 10. Lower cooling plate 11, infrared lamp heater 12 that is a mold heating heat source disposed around quartz tube 8, and cartridge that is a mold heating heat source embedded in each of upper mold 2 and lower mold 3 Heaters 13a and 13b and a release ring 14 disposed between the upper mold 2 and the lower mold 3 are provided.

  The optical element molding apparatus 1 is supported by a vertically closed and closed hermetic furnace (not shown) disposed around a quartz tube 8, an infrared lamp heater 12, and the like, and an upper shaft 4 supported by a frame (not shown). A molding chamber for molding a glass lens 15 surrounded by a drive device (not shown) composed of a servo motor or an air cylinder that moves in the vertical direction and the quartz tube 8, the elevating base body 7, and the base plate 10 is evacuated. Exhaust device (not shown), a flow rate adjusting device (not shown) for sending an inert gas (non-oxidizing gas) such as nitrogen gas which sets the molding chamber to a predetermined pressure, and the glass material 15A An autoloader (not shown) that automatically sets the mold 3 and automatically removes the molded glass lens 15 and controls the temperature, pressure, gas flow rate, vacuum, etc. in the molding chamber and the glass material 15A to the lower mold 3 It has control device controls the position of Tsu preparative (not shown).

  The glass material 15A molded into the glass lens 15 by the optical element molding apparatus 1 is polished to an approximate shape of the designed glass lens 15 as shown in FIG. 2, for example, glass transition point 506 ° C., softening This is a glass material for molding at a point of 607 ° C.

  The upper mold 2 and the lower mold 3 are materials having sufficient strength in a temperature range sufficient to mold the glass lens 15 from a glass material, and are substantially formed of cemented carbide, SIC (silicon carbide), or the like. It constitutes a pair of cylindrical shapes. The upper die 2 and the lower die 3 have substantially the same outer diameter, and are fitted to the upper shaft 4 and the lower shaft 5 by fixing members (not shown) so that the respective shafts pass on the same line. It is fixed.

  In the upper mold 2 of the present embodiment, an aspheric concave lens surface 15a (see FIG. 3) which is one lens surface of the glass lens 15 is molded, and only volume deformation due to thermal contraction of the glass lens 15 is expected. The lower mold 3 has a spherical convex lens surface 15b (see FIG. 3) which is the other lens surface of the glass lens 15 and has a convex molding surface 2a in which an aspheric shape based on the design value is set. Similar to the upper mold 2, it has a convex molding surface 2a in which a spherical shape is set based on a design value that allows only volume deformation due to thermal contraction of the glass lens 15 or the like. The molding surfaces 2 a and 3 a of these molds 2 and 3 are mirror-finished to transfer and form the optical function surface of the glass lens 15.

  Further, in each of the molds 2 and 3, there are cartridge heaters 13a and 13b which are mold heating heat sources arranged through the respective shafts 4 and 5, and a thermocouple (not shown) for detecting the mold temperature. Embedded. These cartridge heaters 13a and 13b heat the upper mold 2 and the lower mold 3 by heat conduction, and heat the glass material 15A through the molds 2 and 3, respectively.

  The upper shaft 4 and the lower shaft 5 are each provided with a cooling path (not shown) through which cooling water for mold cooling can flow. Further, the upper shaft 4 is formed with a step portion in the middle outer peripheral portion. When the upper shaft 4 is lifted, the upper surface of the step portion comes into contact with the opposing surface which is the lower surface of the lift base body 7. The tube 8 and a closed furnace (not shown) are lifted together.

  The sleeve 6 is formed of a cylindrical ceramic material, the upper part is fixed to the upper mold 2 and is precisely fitted (with a very small gap of 5 μm or less), and can slide on the lower mold 3. Are precisely fitted (a very small gap of about 5 μm). Therefore, the irradiation heat from the infrared lamp heater 12 is efficiently transmitted to the upper mold 2 and the lower mold 3 through the quartz tube 8 and the sleeve 6. The sleeve 6 is also used to align the axial centers of the molds 2 and 3 by precisely fitting with the molds 2 and 3.

  The quartz tube 8 can seal or open the surrounding space of the upper die 2, the lower die 3, and the sleeve 6 from the outside, or can be vacuumed or non-oxidized when the glass material 15A is in a sealed state during the molding of the glass material 15A. Each contact portion is sealed so that it can be filled with the atmosphere. A space sealed by the quartz tube 8 becomes a molding chamber 16 for molding the glass lens 15.

  The upper cooling plate 9 and the lower cooling plate 11 have, for example, irregularities formed on their surfaces, and release the heat of the molds 2 and 3 to the outside by increasing the surface area. The cooling plates 9 and 11 may be provided with cooling paths through which the cooling water for mold cooling described above can flow.

  The infrared lamp heater 12 is fixedly supported on the inner wall of a closed furnace (not shown), and is positioned along the outer periphery of the quartz tube 8. The cartridge heaters 13a and 13b, the infrared lamp heater 12, and the refrigerant are controlled by a control unit (not shown) of the optical element molding apparatus 1 described above based on a mold temperature detected by a thermocouple (not shown). The temperature control of the glass material 15A, the upper mold 2 and the lower mold 3 at each step is performed.

  The mold release ring 14 is mounted around the convex molding surface 2 a of the upper mold 2, and moves up and down by a cylinder (not shown) to release the molded glass lens 15 attached to the upper mold 2. belongs to.

  The molding chamber 16 is sealed while the glass lens 15 is pressed from the glass material 15A, and the above inert gas is filled inside from an inert gas supply pipe (not shown) to form an inert atmosphere.

  Next, the process of molding the glass lens 15 by the optical element molding apparatus 1 having the above-described configuration will be described using the flowchart of FIG. The glass lens 15 molded by the optical element molding apparatus 1 of the present embodiment is, for example, a single-sided aspheric concave meniscus lens, the outer diameter is φ12.2 mm, and the concave lens surface 15a side is the paraxial center R4.3. In addition, the design value is determined so as to have an aspherical shape with an effective diameter of 8.6 mm and a convex lens surface 15 b side with a curvature of R36 and a spherical shape with an effective diameter of φ11 mm.

  First, the glass material 15A polished to the approximate value shape formed based on the above-described design value is conveyed by an autoloader (not shown) and placed on the concave molding surface 3a of the lower mold 3 (S1). Then, the molding chamber 16 is sealed with the quartz tube 8 and a closed furnace (not shown) (S2).

  The upper mold 2 is lowered in the direction toward the lower mold 3, and when the convex molding surface 2a of the upper mold 2 reaches the vicinity of the surface of the glass material 15A, the upper mold 2 is temporarily stopped (S3). Therefore, the molding chamber 16 is evacuated under the control of a control unit (not shown) and filled with nitrogen gas, which is an inert gas, by a flow rate adjusting device (not shown) (S4).

  Then, under the control of the control unit of the optical element molding apparatus 1, the cartridge heaters 13a and 13b and the infrared lamp heater 12 are energized to start heating the upper mold 2, the lower mold 3, the sleeve 6, and the glass material 15A. (S5).

  When the target temperature (here, molding temperature 565 ° C.) is reached by detecting the temperature of a thermocouple (not shown), the upper mold 2 is lowered again in the direction of the lower mold 3 to close the mold, and the convex molding surface 2a. Then, the glass material 15A is pressed by the concave molding surface 3a (S6). Next, after a predetermined amount of pressing, energization of the cartridge heaters 13a and 13b and the infrared lamp heater 12 is stopped (S7).

  Then, cooling water (for example, pure water as a refrigerant) is passed through the cooling paths of the shafts 4 and 5 to enter the cooling process, and cooling of the molds 2 and 3 is started (S8). The heat of the upper mold 2, the lower mold 3, and the glass material 15 </ b> A is released to the outside of the system through the refrigerant and is released to the outside air by the cooling plates 9 and 11 by the cooling. Then, the glass material 15 </ b> A is pressed and formed into the shape of the glass lens 15.

  Thereafter, when the mold temperature of each of the molds 2 and 3 does not oxidize from the detection result of the thermocouple (not shown) and falls to a temperature equal to or lower than the deformation temperature, for example, near room temperature (25 ° C.) The shaft 4 is raised, the upper die 2 and the sleeve 6 are raised, and the elevating base body 7 is lifted together with the quartz tube 8 and the closed furnace (not shown) at the step portion of the upper shaft 4. The glass lens 15 is released from 2 (S9). Finally, the glass lens 15 is carried out by an autoloader (not shown) (S10). The glass lens 15 may be thermally contracted by cooling and may be adsorbed to the convex molding surface 2a of the upper mold 2. However, the glass ring 15 is attached to the convex molding surface 2a by moving the release ring 14 up and down. Release without sticking.

  The optical element molding apparatus 1 according to the present embodiment manufactures the glass lens 15 that is a concave meniscus lens by the process procedure as described above. In addition, the shape | molded glass lens 15 will become a shape different from the above-mentioned design value by the difference in the amount of thermal shrinkage with each type | molds 2 and 3 which the shape generate | occur | produces at the time of cooling.

  Therefore, according to each routine of the flowchart of FIG. 5, the optical performance of the designed glass lens 15 is determined with reference to the cross-sectional view of the glass lens 15 of FIG. 3 and the drawings of FIGS. The correction process will be described.

Before that, here is an overview of the concept of type modification.
As shown in FIG. 3, the lens 15 is a desired ideal lens (design lens) having a concave lens surface 15a and a convex lens surface 15b opposite to the concave lens surface 15a, and one of the molded lens surfaces is formed with respect to the concave lens surface 15a. A lens surface 15a ′ having the same shape as that of the convex lens surface 15a is assumed at a position shifted by a slight translation in the direction of the optical axis O. On the other hand, a lens surface 15a ″ having a surface shape error, that is, a curve g1 (r ). Further, the other lens surface formed by molding is assumed to be a lens surface 15b ′ having the same shape as the convex lens surface 15b at a position shifted by a slight translation in the optical axis O direction with respect to the convex lens surface 15b. Suppose that there is a lens surface 15b ″ having a surface shape error, that is, a curve g2 (r). The above-described lens surface 15a 'and lens surface 15b' are assumed to be the distance between the surfaces of the molded lens surfaces along the optical axis O (surface thickness) which is not necessarily the design surface between the surfaces along the optical axis O (surface thickness). It is because it cannot be declared that it is the same.

The intersection between the concave lens surface 15a, which is an ideal lens surface, and the optical axis O is used as the origin, the lens radius r is taken on the horizontal axis, and the intersection between the convex lens surface 15b, which is an ideal lens surface, and the optical axis O is used as the origin. The lens radius r is taken as the axis, the upward direction in the optical axis O direction from each origin (the direction from the lower mold 3 to the upper mold 2) is taken as +, and + from the origin to the lens radial direction (outer diameter direction). In this coordinate system, if the curve representing the concave lens surface 15a that is the ideal lens surface is G1 (r) and the curve representing the convex lens surface 15b that is the ideal lens surface is G2 (r), the curve in the ideal lens 15 at the arbitrary radius r is The plane D parallel to the optical axis O is
D ₀ = G1 (r) + T ₀ −G2 (r) = f ₀ (r)
Can be defined. However, T ₀ {T ₀ = f ₀ (0)} is an inter-plane distance (constant) on the optical axis O.

  Here, what is desired is a plane D = f (r) parallel to the optical axis at an arbitrary radius position. Actually, as described above, the optical axis with respect to the design value such as g1 (r) and g2 (r). A surface displaced in the O direction is formed. Here, g1 (r) and g2 (r) are high-order equations obtained by approximating data obtained by measurement as approximate curves. However, the horizontal axis represents the lens radius r, and the vertical axis represents the amount (μm) based on the ideal lens.

  Therefore, the points where the optical axis O intersects with g1 (r) and g2 (r) are set as the origins, and the upward direction (the direction from the lower mold to the upper mold) is taken as + with the optical axis as the vertical axis from these origins. A coordinate system is defined by a horizontal axis that is + in the lens radial direction (outer diameter direction) from the origin.

The distance D ₁ between the surfaces of the actually molded lens 15 is
_{D 1 = g1 (r) +} T 0 '-g2 (r) = f 1 (r)
Can be defined. However, T ₀ ′ {T ₀ ′ = f ₁ (0)} is an inter-plane distance (constant) on the optical axis O.

Accordingly, the inter-surface error of the actually molded lens 15 with respect to the ideal lens 15 is
_{D 1 -D 0 = g1 (r} ) + T 0 '-g2 (r) -G1 (r) -T 0 + G2 (r) = f 1 (r) -f 0 (r) = Δd (r)
It becomes.

Here, G1 (r), G2 ( r), each term of _{T 0} is a design value, a known value. Accordingly, the remaining terms g1 (r), g2 (r), and T ₀ ′ may be measured and measured, and the mold may be corrected based on this. However, T ₀ ′, which will be described later, may fluctuate at the time of mold correction. Therefore, adjustment between molds can be performed by measuring the molded lens after re-molding after mold correction, and this can be corrected. Therefore, as a matter of course, it is only necessary to correct the mold so that the remaining term g1 (r) -g2 (r) that can be manipulated artificially is minimized.

  That is, in order to minimize g1 (r) -g2 (r), one of the molds may be additionally processed (mold correction), or both molds may be additionally processed (mold correction) depending on circumstances. This is the concept of type correction.

Then, the amount of translational displacement (T ₀ -T ₀ 'in FIG. 3) from the design values of the lens surface 15a' and the lens surface 15b 'and parallel to the optical axis O direction of the lens surface generated during mold correction processing described later. The amount of movement is corrected by adjusting the upper and lower molds during molding.

  First, as shown in FIG. 5, based on the glass lens 15 formed first, the shape within the effective diameter of the convex lens surface 15b is measured by a stylus type surface shape measuring machine or the like. The shape error which is the deviation of the convex lens surface 15b from the value is measured (S11). As an example of the measurement result, in the cross section of the glass lens 15 shown in FIG. 3, the convex lens surface 15b has a shape along the curve shown in FIG. 7, and the optical axis O direction with respect to the design value (designed lens surface shape) Has a maximum error amount Δt2 of about +0.3 μm (S12).

  Specifically, the convex lens surface 15b of the glass lens 15 in the cross section of FIG. 3 that has been press-molded by the lower mold 3 processed based on the design value has a maximum surface shape error amount from point Q1 to point Q2 here. It has become.

  Next, the shape within the effective diameter of the concave lens surface 15a of the molded glass lens 15 is measured by a stylus type surface shape measuring machine or the like, and a shape error that is a deviation of the concave lens surface 15a between the measurement result and the above-described design value is measured. Measure (S13). As an example of the measurement result, in the cross section of the glass lens 15 shown in FIG. 3, the concave lens surface 15a has a shape along the graph curve shown in FIG. 6, and the optical axis O with respect to the design value (designed lens surface shape). The surface shape error amount in the direction had an error amount Δt1 of approximately +0.8 μm (S14).

  Specifically, the concave lens surface 15a of the glass lens 15 in the cross section of FIG. 3 that has been press-molded by the upper mold 2 processed based on the design value is the maximum surface shape error amount from the point P1 to the point P2 here. It has become.

  The glass lens 15 after molding at this stage has shape error amounts Δt1 and Δt2 with respect to the design values on the concave lens surface 15a and the convex lens surface 15b, and these shape error amounts Δt1 and Δt2 are combined so that the performance of the lens itself is combined. For example, the optical performance of a lens formed by combining a plurality of lenses is extremely deteriorated, resulting in a defective product.

  However, the shape error from the design value is slight (in the present embodiment, in the concave lens surface 15a, the shape error amount Δt1 with respect to the design value is an error amount of about 0.8 μm or less at the maximum). If the distance between the surfaces 15a and 15b parallel to the optical axis O is equal to the design value, it is confirmed that the optical performance is satisfied. For this reason, the glass lens 15 corrects either one of the lens surfaces so that the distance parallel to the optical axis O between the lens surfaces 15a and 15b is equal to the design value. Alternatively, either one of the lower molds 3 may be reworked. In some cases, both molds 2 and 3 may be reworked.

  In the present embodiment, the lower mold 3 having the spherical concave molding surface 3a that can be initially processed at low cost remains in the state based on the design value, and only the upper mold 2 having the aspherical convex molding surface 2a. Then, the concave lens surface 15a of the glass lens 15 is corrected. That is, the concave lens surface 15a is corrected by the reprocessed upper mold 2, and the glass lens 15 is press-molded using the upper mold 2 and the lower mold 3 with the initial processing.

Here, the distance parallel to the optical axis O between the lens surfaces 15a and 15b of the glass lens 15 will be described. As shown in FIG. 3, the distance parallel to the optical axis O between the lens surfaces 15a and 15b of the glass lens 15 at a distance r in the radial direction from the optical axis O can be defined as D = f (r). It can be easily calculated by using the approximate higher-order expression as described above representing the surface shapes of 15a and 15b.
Therefore, the shape error measurement results obtained in steps S12 and S14 are synthesized by the above-described g1 (r) -g2 (r) (see FIG. 8), and the synthesized shape error R is calculated (S15). The combined shape error R becomes a combined shape error R having a width of about 0.48 μm as shown in the graph (see FIG. 9). Specifically, the distance D ₁ parallel to the optical axis O of the molded glass lens 15 is a graph curve shown in FIG. 9 with respect to the distance D ₀ parallel to the optical axis O of the glass lens 15 determined based on the design value. And has an error of 0.48 μm and an unknown amount of parallel movement to the optical axis O with respect to the design optical surface.

  Accordingly, the convex molding surface 2a of the upper mold 2 is corrected along the shape shown in the graph curve without first considering the unknown parallel movement in the direction of the optical axis O.

Further, the functions shown in FIGS. 6 to 9 represent the shapes of the lens surfaces 15a and 15b of one cross section through which the optical axis O of the glass lens 15 shown in FIG. The shape error R is calculated by calculation.
The operation of each routine described above is the first step of the present embodiment.

  Here, it is determined whether the combined shape error in step S16 satisfies the optical performance, in other words, whether the error amount (error width) is equal to or less than a predetermined value. If this error amount is less than or equal to a predetermined value, the process proceeds to step S20, which will be described later, and if it exceeds the predetermined value, the process proceeds to steps S17 and S18 which are mold correction processes.

  Next, the convex molding surface 2a of the upper mold 2 is reworked based on the combined shape error (corrected shape R) obtained in step S15 (S17). Specifically, only the convex molding surface 2a of the upper mold 2 is shown in FIG. 9 based on the corrected shape R, in which the molded glass lens 15 is a combined shape error amount in a direction parallel to the optical axis O with respect to the design value. Cutting according to the trajectory of the graph curve shown.

  One of means for this correction processing (additional processing) will be described with reference to FIG. G ″ in FIG. 10A is the result of FIG. 9, that is, the amount calculated from g1 (r) −g2 (r) is inverted on the uncorrected convex molding surface 2a, that is, − (g1 ( r) shows a diagram reflecting -g2 (r)). Here, coordinates with the surface of the center of the optical axis of the mold as 0 are taken.

  The (+) portion in the graph of FIG. 9 indicates that the thickness of the molded glass lens is relatively excessive, and the (−) portion indicates that the thickness is relatively insufficient. For this reason, a wall thickness p exceeding the thickness of the (+) portion in the graph of FIG. 9 is built up on the entire upper mold surface by welding, hard plating, etc., and the whole build up is cut, ground and polished. It is conceivable that a necessary curve g ″ is obtained within the effective diameter by performing necessary additional processes such as the above. That is, the region S1 in FIG. 10A, which is a meat portion from the build-up surface to the curve g ″, is removed. However, the (+) portion in FIG. 10 (a) is subjected to the additional processing as described above for the upper die part together with the build-up portion.

As another means, as shown in FIG. 10B, the maximum value of the (+) amount in the graph in FIG. Assuming a curved line 2a ″ that exceeds the parallel movement, the curve g ″ is overlaid on the curved line 2a ″, and at least within the effective diameter, between the currently uncorrected convex molding surface 2a and the curve g ″. Further, necessary additional processing such as cutting, grinding, polishing, etc. is performed so as to remove the region S2 of FIG.
Of the above two means, the latter step is simple.

Incidentally, in consideration of the distance D ₁ of the optical axis O and parallel to the direction between the lens surfaces 15a, 15b of the glass lens 15 based on the design value when the fixed upper mold 2 to the upper shaft 4, the upper mold 2 and the lower The position in the height direction away from the mold 3 is adjusted. Alternatively, the stroke between the molds when the mold is closed may be adjusted.

At this stage, a distance T ₀ ′ parallel to the optical axis O of each lens surface 15 a, 15 b of the glass lens 15 to be molded and a parallel to the optical axis O of each lens surface 15 a, 15 b of the designed glass lens 15. Without considering the match of the distance T ₀ , the concave molding surface 3 a of the lower mold 3 is not processed, and only the convex molding surface 2 a of the upper mold 2 is reworked according to the composite shape error (corrected shape R). The operation in step S17 is the second step in the present embodiment.

  Next, the glass lens 15 is molded from the glass material 15A by the optical element molding apparatus 1 using the reprocessed upper mold 2 and the unprocessed lower mold 3 (processed based on the design value) ( S18). Since this routine is the same as the procedure of steps S1 to S10 shown in the flowchart shown in FIG. 4, detailed description thereof is omitted.

  Then, the surface shape of the concave lens surface 15a of the formed glass lens 15 is measured by a stylus type surface shape measuring machine or the like (S13). As an example of the measurement result, as shown in FIG. 11, the shape error amount Δt ′, which is an error amount having a width of 0.35 μm in the optical axis O direction with respect to the design value, is formed on the concave lens surface 15a of the glass lens 15. Had. Here, a diagram representing a surface shape error with respect to a design value is defined as g1m (r).

  Based on the shape error amount Δt1 ′ of the concave lens surface 15a in step S14 and the shape error amount Δt2 (here 0.3 μm) of the convex lens surface 15b in step S14, the combined shape error with respect to the design value of the glass lens 15 Is calculated.

  For this calculation, as performed in step S16, g2 (r) representing the surface shape error and g1m (r) representing the surface shape error of the concave lens surface 15a formed by correcting the mold are superimposed (FIG. 12). ) The difference is calculated as g1m (r) -g2 (r). This result is shown in FIG. 13, which is a diagram representing the composite shape error, and the interval between the maximum value and the minimum value of this diagram is the final composite surface shape error.

  As an example of the result, as shown in FIG. 13, the glass lens 15 after molding has a composite surface shape error formed by the lens surfaces 15a and 15b within the effective diameter of 0.1 μm or less with respect to the design value. The maximum error was within 0.09 μm.

  Next, based on the result in step S15, it is determined whether or not the molded glass lens 15 satisfies a predetermined optical performance (S16). The judgment here is that the amount of error parallel to the optical axis O of each lens surface 15a, 15b within the effective diameter of the glass lens 15 after molding satisfies the optical performance with the amount of error Δd (r) with respect to the designed optical surface. It is determined whether the allowable accuracy (quality) is within ± 2 μm (−2 μm ≦ Δd (r) ≦ + 2 μm), and if it is within the allowable accuracy range that can satisfy this optical performance. In the fourth step, which is the next step, adjustment between molds is performed.

  If the composite surface shape error amount is not within ± 2 μm, the process proceeds to step S17 again, and each routine (steps S17, 18, S13 to S16) is performed. The routine performed in steps S17 to S16 is the third step of the present embodiment.

And the 4th process which is the last process is demonstrated. In this step, the glass lens 15 molded by the modified type, T ₀ thickness in the optical axis O center as described above, with respect to T ₀ is a design value, that dimension is deviated from that value Since it is molded with the dimension ', the optical axis O center thickness T ₀ ' of the molded glass lens is measured, and the difference from the design value D ₀ is adjusted between the molds during molding (S19). According to this, the difference is removed only by relatively changing the interval between the pair of surfaces in which the combined surface shape error is corrected without damaging the correction.

  As described above, the glass lens 15 has an allowable accuracy (quality) that satisfies a good optical performance because the relative distance between the convex lens surface 15b and the concave lens surface 15a is substantially the same as a value determined by design.

  Using the upper mold 2 reworked for the shape correction described above and the lower mold 3 machined based on the design value, the optical element molding apparatus 1 allows the glass lens 15 of continuous 10,000 shots or more. As a result of performing the molding and verifying, all of the molded glass lenses 15 have satisfactory optical performance with respect to the design distance with the distance parallel to the optical axis O between the lens surfaces 15a and 15b. The result was an error amount within ± 2 μm which was an acceptable accuracy (quality).

  In the present embodiment, only the aspherical convex molding surface 2a of the upper mold 2 which is one of the pair of molds is reworked, and the spherical concave shape of the lower mold 3 which is the other of the pair of molds. Since the molding surface 3a is not reworked, it does not require time and effort to recreate the mold, and inexpensive initial machining is sufficient, and the lead time in machining the mold itself can be shortened in a period of one month or longer. Further, when the upper mold 2 is reworked, the initial machining of the lower mold 3 is completed, so the processing machine for processing the mold molding surface is concentrated on reworking the convex molding surface 2a of the upper mold 2 It was possible to distribute the operation of the processing machine.

  As described above, according to the glass optical element molding method of the present embodiment, the lens surfaces 15a and 15b of the glass lens 15 to which the molding surfaces 2a and 3a are transferred by press molding with the pair of molds 2 and 3 are used. Even if the surface accuracy of the glass lens 15 is not taken into consideration, the distance between the lens surfaces 15a and 15b, which is the approximate shape of the glass lens 15, parallel to the optical axis O is adjusted to the design value by the above-described simple method. Since the optical performance can be satisfied, it can be easily set even in the molding of difficult-shaped optical elements.

  Further, the glass optical element molding method of the present embodiment is a glass lens to be molded without changing various settings of the optical element molding apparatus 1 many times so as to satisfy the good optical performance of the glass lens 15. In accordance with the sampling of 15, it is only necessary to correct the upper die 2 for adjusting the distance parallel to the optical axis O between the lens surfaces 15a and 15b to the distance determined based on the design value, so that labor is not required. Thus, the time can be shortened, and the productivity of the glass lens 15 can be improved. In addition, since the glass optical element molding method of the present embodiment does not need to slow down the cooling rate of the glass lens 15, it is possible to prevent an increase in the cycle time of manufacturing the glass lens 15 and avoid the problem of poor productivity. can do. From the above results, the yield in manufacturing the glass lens 15 can be improved.

  In this embodiment, the convex molding surface 2a side of the upper mold 2 is corrected. However, the present invention is not limited to this, and the concave molding surface 3a side of the lower mold 3 is the optical axis between the lens surfaces 15a and 15b. You may perform the correction process which correct | amends the shift | offset | difference part which is a synthetic | combination shape error with the distance along the axis | shaft parallel to O, and the distance determined by a design value.

  Further, in the present embodiment, the glass lens 15 having the spherical surface of the convex lens surface 15b is taken as an example. However, the present invention is not limited to this, and the lens surface 15a, 15b can be applied to the glass lens 15 having an aspherical shape. It is. That is, correction processing may be performed by feeding back the amount of the shift portion to one of the molds 2 and 3 that transfer the optical surfaces to both lens surfaces 15a and 15b.

  Further, in the present embodiment, the annealing process for adjusting the refractive index of the glass lens 15 is not performed. However, when the annealing process is performed, the above-described misalignment portion is determined based on the shape of the glass lens 15 after annealing. Only one of the pair of molds 2 and 3 may be corrected so as to cancel the amount.

(Second Embodiment)
The glass optical element molding method of the present embodiment is a glass lens in which the effective diameters of the pair of optical surfaces are different from each other with respect to the glass lens 15 having the same effective diameter of the pair of optical surfaces to be molded in the first embodiment. Is formed and corrected. Here, about each structure described in 1st Embodiment, the detailed description is abbreviate | omitted using the same code | symbol.

  Below, the glass optical element shaping | molding method of this Embodiment from which the effective diameter of a pair of optical surface differs mutually is demonstrated using FIGS. FIG. 14 is a plan view of the glass lens 15 viewed from the concave lens surface 15a. FIG. 15 is a plan view of the glass lens 15 viewed from the convex lens surface 15b. FIG. 16 is a cross-sectional view of the glass lens 15 taken along line XI-XI in FIGS. 14 and 15. 15 shows a state in which only the aa ′ direction shown in FIG. 14 is reversed and the glass lens 15 of FIG. 14 is turned upside down without changing the bb ′ direction shown in FIG. ing.

  As shown in FIG. 14, the concave lens surface 15a of the glass lens 15 has a first effective diameter Z1, and the convex lens surface 15b of the glass lens 15 has a second effective diameter Z2 as shown in FIG. Have. The glass lens 15 of the present embodiment is a concave meniscus lens in which the effective diameter Z2 on the convex lens surface 15b side is larger than the effective diameter Z1 on the concave lens surface 15a side (Z1 <Z2).

Below, the glass optical element shaping | molding method of this Embodiment is demonstrated.
The distance between one point at an arbitrary radius from the center of the optical axis on the lens surface 15a that is one surface of the molded glass lens 15 and one point that will be described later on the lens surface 15b that is the other surface corresponding to the one point. In the description, it is referred to as “between molded pseudo-surfaces”): one point at an arbitrary radius from the center of the optical axis O on the lens surface 15a, which is one surface of the designed glass lens 15, and the other surface corresponding to the one point. If the distance between a lens surface 15b and a later-described point (this is referred to as “design pseudo-between” in this description) is substantially the same, the molded glass lens 15 has an optical performance at a required radius. It has been confirmed that they are satisfied. Therefore, in the present embodiment, the glass lens 15 that is a glass optical element is formed by a method as described below.

  First, as in the first embodiment, the optical element molding apparatus 1 uses the molds 2 and 3 in which the molding surfaces 2a and 3a based on the design of the glass lens 15 are processed according to the procedure of the flowchart shown in FIG. The glass lens 15 is pressed and formed. Then, similarly to steps S11 and S13 in the first embodiment, the shapes of the lens surfaces 15a and 15b of the glass lens 15 within the effective diameter are measured by a stylus type surface shape measuring machine or the like.

  Next, an arbitrary first point A on the concave lens surface 15a at the first radial distance r1 from the optical axis O within the effective diameter Z1 of the glass lens 15 from the molded glass lens 15 (FIG. 14). Then, depending on the ratio of the effective diameter Z1 of the concave lens surface 15a and the effective diameter Z2 of the convex lens surface 15b, within the effective diameter Z2 on the convex lens surface 15b corresponding to the first point A at the first distance r1 on the concave lens surface 15a. The position of the second point A ′ at (see FIG. 15) is specified.

In specifying the second point A ′, first, a second distance r2 in the radial direction from the optical axis O is obtained. Specifically, the second distance r2 from the optical axis O at the point A ′ on the convex lens surface 15b corresponding to the arbitrary point A is
Z2 × r1 / Z1 = r2 (4)
It can be calculated from

  That is, this point A ′ is a point in the plane having the point A of the concave lens surface 15a and the optical axis O, and is in the cross section of the glass lens 15 shown in FIG. This is a point at a distance r2 from the optical axis O in the vicinity of the point A and at a position where a straight line orthogonal to the optical axis O and the convex lens surface 15b intersect.

  Next, the respective error amounts Δt1 and Δt2 with respect to the design values at the position of the point A on the concave lens surface 15a and the point A ′ on the convex lens surface 15b are calculated from the values measured by the stylus type surface shape measuring instrument. Then, these error amounts Δt1 and Δt2 are combined in the same manner as in the first embodiment, and a combined shape error with respect to the design value of the molded glass lens 15 is calculated. At the time of this synthesis, the diagrams representing the errors on the lens surfaces 15a and 15b are not simply synthesized because they are shifted from each other in the horizontal axis direction in the comparison between the arbitrary points A and A '. In the synthesis of this diagram, the effective diameter ratio is multiplied or divided by one horizontal axis of the concave lens surface 15a or the convex lens surface 15b. This combined shape error becomes the corrected shape R in the present embodiment.

That is, in the present embodiment, the distance in the direction parallel to the optical axis O in the first embodiment is not calculated from the corrected shape R of the lens surfaces 15a and 15b of the glass lens 15, The distance L ₁ (r1) between the corresponding points A and A ′ according to the ratio of the effective diameters Z1 and Z2 of the lens surfaces 15a and 15b is adjusted according to an error from the distance L ₀ (r1) determined based on the design value. Calculated from the corrected shape R.

  In addition, as the point A ′ on the convex lens surface 15b with respect to the arbitrary point A on the concave lens surface 15a at each effective diameter Z1 and Z2 of the glass lens 15 after molding is specified, a plurality of arbitrary positions on the concave lens surface 15a are specified. A point A ′ on the convex lens surface 15b with respect to the point A is specified based on the equation (4) and calculated from the correction shape R described above.

  Then, in the same manner as in the first embodiment, in order to correct the concave lens surface 15a of the glass lens 15 after molding, the concave molding surface 3a of the lower mold 3 is not processed, and the convex molding of the upper mold 2 is performed. Only the surface 2a is reworked based on the corrected shape R. Next, using the reprocessed upper mold 2 and the unreprocessed lower mold 3 (processed based on the design value), the optical element molding apparatus 1 performs the same as in the first embodiment. The glass lens 15 is molded from the glass material 15A.

  When the glass lens 15 is press-molded using the modified upper mold 2, the adjustment between the molds at the center of the optical axis or the upper shaft 4 is performed as in the first embodiment. In consideration of the design glass lens 15 when the upper mold 2 is fixed to the head, the position adjustment in the height direction in which the upper mold 2 and the lower mold 3 are separated from each other is performed.

  Next, the combined shape error in the re-formed glass lens 15 is calculated in the same manner as described above.

Note that the point A ′ on the convex lens surface 15b with respect to an arbitrary point A on the concave lens surface 15a in the effective diameters Z1 and Z2 of the lens surfaces 15a and 15b of the molded glass lens 15 is specified, so that it is on the concave lens surface 15a. identify A'point on the convex lens surface 15b for a point a of arbitrary plural portions, measured the points a, connecting the A'lens surface 15a, the second distance L ₁ between 15b at a plurality of locations, Comparison is made with the first distance L ₀ (r1) connecting the points A and A ′ determined by the corresponding designs.

Further, an error amount ΔL (r1) in the length between the points AA ′ of the molded glass lens 15 and the designed glass lens 15 is expressed as follows.
L ₀ (r1) −L ₁ (r1) = ΔL (r1) (5) (where r2 is the above equation (4)).
Can be defined.

  In the glass optical element molding method of the present embodiment, the error amount ΔL (r1) with respect to the design pseudo surface at each point between the obtained lens surfaces 15a and 15b is substantially zero (ΔL (r1) ≈0). In the same manner as in the first embodiment, only the convex molding surface 2a of the upper mold 2 is additionally processed for correction. Then, adjustment between molds is performed as necessary to mold the lens.

The glass lens 15 thus molded has two portions on the lens surfaces 15a and 15b at the distances r1 and r2 from the optical axis O corresponding to the ratio of the effective diameters Z1 and Z2 of the lens surfaces 15a and 15b. point (a, A') to be substantially the same length as the distance L ₀ between the lens surfaces 15a, 15b at the same points position on the design distance L ₁ between, that shape is corrected, the Even if the lens surfaces 15a and 15b have a shape deviation within a minute error region with respect to the design value, better optical performance can be satisfied.

In the above description of the invention, it has been described that adjustment between molds may be performed in order to make T ₀ ′ match or approach T ₀ , but this adjustment is not always necessary. That is, as one case, for thin than wall thickness of molded glass lenses (interplanar distance) is generally ideal lens (design lens), the lens molded with respect to the surface between T ₀ of the ideal lens Additional processing may be performed so that the amount of shrinkage is taken into account and calculated. If T ₀ ′ of the glass lens 15 molded again from this calculated value deviates greatly from T _0, it is only necessary to adjust the mold.

  In addition, according to the present invention, the lens can be easily corrected without correcting to the ideal lens surface shape as designed, and the lens can be produced without spending enormous time on the mold processing, which contributes to the improvement of productivity. It is.

  Further, the present invention may be carried out by comparing the shape after annealing for adjusting the refraction of the lens with the design lens shape.

  In the optical element molding apparatus 1 of each of the above embodiments, the upper mold 2 side is a movable mold. However, the present invention is not limited to this, and the upper mold 2 side is a stationary mold and the lower mold 3 side is a movable mold. A similar configuration can be applied.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in each embodiment, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the effects of the invention can be achieved. In the case of being obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

  By using the glass optical element molding method according to the present invention, the glass optical element molding method can be applied to an optical element molding apparatus that improves productivity for manufacturing an optical element that satisfies satisfactory optical performance.

It is sectional drawing which shows the inside of the optical element shaping | molding apparatus which concerns on the 1st Embodiment of this invention. 2 is a cross-sectional view showing a pair of molds, a sleeve, and a glass material of the optical element molding apparatus of FIG. FIG. 3 is a cross-sectional view of the molded glass lens. 3 is an operation flowchart of the optical element molding apparatus for molding a glass lens from a glass material. 4 is an operation flowchart for molding an optical element that approximates a design value so as to satisfy optical performance. 4 is a function graph showing the shape of a concave lens surface in one section of the glass optical element in FIG. 4 is a function graph showing the shape of a convex lens surface in one section of the glass optical element of FIG. FIG. 8 is a function graph in which the functions shown in FIGS. 6 and 7 are superimposed. FIG. 8 is a function graph in which the functions shown in FIGS. 6 and 7 are synthesized. FIG. 10A is a diagram showing a state in which the cross section of the glass lens after molding is superimposed on the cross section of the upper mold for explaining one of the means for correction processing (additional processing), and FIG. FIG. 11 is a view showing a state in which the cross section of the glass lens after molding is superimposed on the cross section of the upper mold for explaining another means different from one of the means of correction processing (additional machining) in FIG. . It is a function graph which shows the shape of the concave lens surface in one cross section of the glass lens shape | molded by the convex shape molding surface of the upper mold | type after a process similarly. FIG. 6 is a functional graph showing the shape of a concave lens surface in one cross section of a glass lens in a state where a surface shape error and a surface shape error of a concave lens surface that has been mold-corrected are superimposed. 10 is a function graph obtained by synthesizing the functions shown in FIGS. 7 and 9. It is a top view of the glass lens seen from the concave lens surface which concerns on the 2nd Embodiment of this invention. It is a top view of the glass lens seen from the convex lens surface. It is sectional drawing of the glass lens along the XI-XI line | wire of FIG. 13 and FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical element shaping | molding apparatus 2 ... Upper type | mold (one of a pair of type | molds)
2a ... convex molding surface 3 ... lower mold (the other of a pair of molds)
3a: concave molding surface 15A: glass material 15: glass lens (optical element)
15a ... concave glass surface (optical surface)
15b ... convex glass surface (optical surface)
O ... Optical axis

Claims (3)

In a glass optical element molding method of molding a glass optical element by pressing a glass material with a pair of molds,
The pair of optical surface shapes and the design of the glass optical element molded using the pair of molds having the optical molding surface processed into a shape capable of transferring an optical surface shape based on the design value of the glass optical element. A first step of measuring a difference from the optical surface shape determined based on the value;
In order to make the distance between the optical surfaces parallel to the optical axis of the pair of optical surfaces of the glass optical element based on the measured difference equal to the distance determined based on the design value, A second step of processing the optical molding surface of one mold;
A third step of molding the glass optical element together with the processed one mold and the other of the pair of molds;
A glass optical element molding method comprising: A glass optical element molding method for molding a glass optical element by pressing a glass material with a pair of molds,
The distance from the optical axis at an arbitrary point on the pair of optical surfaces of the glass optical element is r, and the distance D ₀ parallel to the optical axis between the pair of optical surfaces in the design value of the glass optical element is expressed by the following equation: when expressed in (1), when the distance D ₁ parallel to the optical axis between the pair of optical surfaces of said molded glass optical element and the following formula (2),
In order to make the difference Δd (r) represented by the following (3) substantially zero {Δd (r) ≈0}, adjustment between the molds at the time of processing and molding is performed on at least one of the pair of molds, A glass element molding method comprising pressing the glass optical element with the pair of molds.
D ₀ = f ₀ (r) (1)
D ₁ = f ₁ (r) (2)
D ₁ −D ₀ = f ₁ (r) −f ₀ (r) = Δd (r) (3)
However, f ₀ (r) and f ₁ (r) are functional expressions relating to the distance r. A glass material is pressed by a pair of molds, and includes a first optical surface having a first effective diameter Z1 and a second optical surface having a second effective diameter Z2 different from the first effective diameter Z1. In a glass optical element molding method for molding a glass optical element,
In the designed glass optical element, an arbitrary first point on the first optical surface at a first radial distance r1 from the optical axis and a radius from the optical axis on the second optical surface. The first distance L ₀ (r1) connecting the second point at the second distance r2 derived from the following formula (1) of the direction, and the first optical distance in the glass optical element after molding An arbitrary first point at the first distance r1 in the radial direction from the optical axis on the optical surface of the optical surface and the following equation (1) in the radial direction from the optical axis on the second optical surface: From the distance L ₁ (r1) connecting the second point at the second distance r2, the difference ΔL (r1) represented by the equation (2) is substantially zero, so that the pair of molds At least one of the optical surfaces is processed and the mold is adjusted during molding, and the glass optical element is pressed by the pair of molds. Glass optical element molding method which is characterized in that shape.
Z2 × r1 / Z1 = r2 (1)
L ₀ (r1) −L ₁ (r1) = ΔL (r1) (2)

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