JP2010269989A - Method for manufacturing optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mold an optical element using an official mold designed with the anticipated change of the refractive index distribution and the shape of the optical element after the outline processing and the like of the optical element molded by a provisional mold. <P>SOLUTION: The method for manufacturing the optical element has a primary step (S1) of: molding a glass stock 23 using the provisional mold; a secondary step (S2) of: carrying out the centering processing of the lens 35 molded in the primary step; a step (S3) of: measuring the optical performance of the optical element 36 after the secondary step; a computing step (S3) of: computing the difference between the measured optical performance of the optical element 36 and a designed performance; a step (S5) of: deciding the provisional mold as the official mold when the difference of the computed performance is allowable; and a molding step (S6) of: molding the optical element 36 using the decided official mold and when the difference computed in the computing step (S3) is not allowable, a step of returning up to the primary step (S1) after the correction (S4) of the provisional mold is repeated until the difference is allowed. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing an optical element in which a molding die is corrected according to the optical performance of the molded optical element, and the optical element is molded with the corrected molding die.

  Conventionally, in order to manufacture an optical element using a mold, the optical element is first molded by a temporary mold (mold before correction), and then the optical element formed by using the temporary mold is optical. Measure performance. Furthermore, based on the measurement result of the optical performance of the optical element, the provisional mold is corrected and the optical element is molded with the corrected formal mold.

  For example, in Patent Document 1, the internal refractive index distribution of an optical element is measured, and the aberration generated due to the refractive index distribution is converted into the shape of the optical element and reflected in the mold, thereby preliminarily reflecting the optical element. A technique is disclosed in which molding is performed using a mold that allows for a refractive index distribution of the above.

JP 2002-193627 A

  However, generally, after the optical element is formed, a centering process (outer diameter process) or an antireflection film is formed. At that time, if the internal stress (refractive index distribution) remains in the optical element, the refractive index distribution and the surface shape of the optical element change when a part of the internal stress is released by a centering process or the like thereafter. End up.

Alternatively, when a new thermal history such as formation of an antireflection film is added to the optical element after the optical element is molded, at least one of the refractive index distribution and the surface shape changes. Therefore, unless molding is performed in view of these, an optical element that satisfies the final performance cannot be obtained.
However, in the above-mentioned Patent Document 1, no consideration is given to the influence of performing the centering process or the formation of the antireflection film.

  The present invention was made in order to solve such problems, and was designed with the expectation of a change in refractive index distribution and surface shape after an outer diameter processing or the like was performed on an optical element molded with a temporary mold. It aims at providing the manufacturing method of the optical element which shape | molds with a type | mold.

In order to achieve the above object, a method of manufacturing an optical element according to the present invention includes:
A primary process of forming an optical element material using a temporary mold;
A secondary step of performing at least one of outer diameter processing and formation of an antireflection film on the optical element molded in the primary step;
Measuring the optical performance of the optical element after the secondary step;
A calculation step of calculating a deviation between the measured optical performance of the optical element and a design value;
When the calculated deviation is allowed, determining the provisional type as a formal type; and
A molding process for molding the optical element material using the determined formal mold,
If the deviation calculated in the calculation step is not allowed, the provisional mold is corrected and the process returns to the primary step until the deviation is allowed.

In addition, the method for manufacturing an optical element according to the present invention includes:
Furthermore, before the secondary step, it has a first measurement step of measuring the optical performance of the optical element molded in the primary step,
From the measurement result of the first measurement step and the measurement result of the optical performance of the optical element after the secondary step, it is possible to calculate the change in the optical performance due to the secondary step.

In addition, the method for manufacturing an optical element according to the present invention includes:
Furthermore, before the molding step,
A step of preforming an optical element material using the formal mold;
A third measuring step for measuring the optical performance of the preformed optical element;
After the third measurement step, a preliminary secondary step of performing at least one of outer diameter processing and antireflection film formation on the optical element;
A fourth measuring step for measuring the optical performance of the optical element after the preliminary secondary step,
From the measurement result of the third measurement step and the measurement result of the fourth measurement step, it is possible to calculate a change in optical performance due to the preliminary secondary step.

In addition, the method for manufacturing an optical element according to the present invention includes:
The change in the optical performance is due to a change in at least one of a refractive index distribution and a surface shape of the optical element,
The optical performance can be measured using a transmitted wavefront measurement method.

  According to the present invention, there is provided a method of manufacturing an optical element that is molded by a formal mold designed in consideration of a change in refractive index distribution and surface shape after the outer diameter processing or the like is performed on the optical element molded by a temporary mold. Can be provided.

It is sectional drawing of the manufacturing apparatus of an optical element. It is sectional drawing of the state which incorporated the glass raw material in the type | mold set. It is sectional drawing of the shape | molded lens. It is a figure which shows the outline | summary of a transmitted wavefront measuring apparatus. It is a figure which shows schematic structure of the centering apparatus. It is sectional drawing of the lens after a centering process FIG. 3 is a diagram illustrating a flowchart for determining a formal type from the provisional type according to the first embodiment and producing an optical element using the formal type. It is a figure which shows the outline | summary of the formation apparatus of a thin film. FIG. 10 is a diagram illustrating a flowchart for determining a formal type from the provisional type according to the second embodiment and producing an optical element using the formal type. FIG. 10 is a diagram illustrating a flowchart for determining a formal type from a provisional type according to Embodiment 3 and producing an optical element using the formal type.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Summary of Invention]
1 is a cross-sectional view of the optical element manufacturing apparatus 10, FIG. 2 is a cross-sectional view of a state in which a glass material 23 is incorporated in a mold set 17, and FIG. 3 is a cross-sectional view of a molded lens 35.

  In FIG. 1, an optical element manufacturing apparatus 10 has a molding chamber 14 partitioned by a heat insulating plate 11 laid on a floor surface and a casing 12 covering the upper part thereof. The molding chamber 14 is operated under atmospheric pressure, replacement with an inert gas (such as Ar gas or nitrogen gas), or under vacuum pressure.

  In this way, by operating the molding chamber 14 under the substitution of an inert gas or the like, it is possible to prevent oxidation of the mold set 17 and the like described later. This is because the inside of the molding chamber 14 is generally at a high temperature due to heating or the like and oxidation may be accelerated. The molding chamber 14 is provided with a pipe (not shown) through which gas can flow in and out, so that the inside of the molding chamber 14 can be replaced with an inert gas or the like.

  At the entrance of the molding chamber 14, a carry-in shutter 15 is provided so that the mold set 17 can be carried in the horizontal arrow A direction. Similarly, a carry-out shutter 16 is provided at the outlet of the molding chamber 14 so that the mold set 17 can be carried out in the arrow A direction.

These carry-in and carry-out shutters 15 and 16 are attached to the base blocks 18 and 19 so as to be opened and closed in a direction substantially orthogonal to the arrow A direction (front and back direction in FIG. 1). The base block 18 and 19, the height from the upper surface of the heat insulating plate 11 has a height substantially the same height of the lower plate 25 ₁ in the heating stage 20 to be described later. Thus, the mold set 17 can be smoothly conveyed.

  In the molding chamber 14, a heating stage 20, a press stage 21, and a cooling stage 22 are disposed along the conveying direction (arrow A direction) of the mold set 17. In each of these stages, it is possible to individually control heating time, pressing time, and the like. These controls are performed by the control device 30 that controls the entire device.

  In the present embodiment, the case where the molding chamber 14 has three stages will be described, but the present invention is not limited to this. For example, in order to perform finer control, each stage can be further subdivided or integrated.

Heating stage 20 includes a vertical upper plate 24 ₁ and the lower plate 25 ₁ a pair of opposite (arrow A direction of arrow B perpendicular to the direction), the upper plate 24 ₁ via the actuating rod 27 ₁ vertical direction (arrow It has an air cylinder 26 _1, the driving in the B direction). The air cylinder 26 ₁ is fixed to the housing 12 via the holding member 13 _1.

An upper cartridge heater 28 ₁ and a lower cartridge heater 29 ₁ are incorporated in the upper plate 24 ₁ and the lower plate 25 ₁ , respectively. The upper and lower cartridge heaters 28 ₁ and 29 ₁ heat the mold set 17 and the glass material 23 inside.
The mold set 17 is carried into the molding chamber 14 in the direction of arrow A by a conveyance device (not shown). Then, the mold set 17, which is carried is transferred between the upper plate 24 ₁ and the lower plate 25 ₁ of the heating stage 20. Then, by the lowering operation of the upper plate 24 ₁ by the air cylinder 26 _1, clamping the mold sets 17, the operation of the clamping pressure or the like is performed.

The press stage 21 and the cooling stage 22 also have the same configuration as the heating stage 20. In this press stage 21, the mold set 17 is sandwiched and heated until the glass material 23 in the interior has a moldable viscosity. In the cooling stage 22, the mold set 17 is sandwiched to stabilize the shape of the molded intermediate lens 31 and cool it to a temperature at which it can be taken out.
In addition, in the heating stage 20, the press stage 21, and the cooling stage 22, the same or corresponding members are denoted by 1, 2, and 3 subscripts, and the description thereof is omitted.

In the press stage 21, the glass material 23 in the mold set 17 is press-molded into the intermediate lens 31 having a predetermined shape by the lowering operation of the air cylinder 26 _2.
The mold set 17 that has been molded by the press stage 21 is then transferred to the cooling stage 22 where the intermediate lens 31 molded into a desired shape is cooled to a predetermined temperature to stabilize the shape. After being cooled, the mold set 17 is unloaded from the molding chamber 14 in the direction of arrow A by opening the unloading shutter 16.
The heating temperature and the press amount at the heating stage 20, the press stage 21, and the cooling stage 22 described above are controlled by the control device 30.

In FIG. 2, the mold set 17 includes a lower mold 32, an upper mold 33, and a sleeve (trunk mold) 34. The lower mold 32 and the upper mold 33 are inserted from both ends of the sleeve 34 so that the molding surfaces 32a, 32b, 33a, and 33b face each other inside the sleeve 34.
The lower mold 32 has a cylindrical shape. The molding surface 32a at the center of the lower mold 32 is formed in, for example, a concave spherical shape or a concave aspherical shape. A spherical glass material 23 is placed on the molding surface 32a. Moreover, the outer peripheral part of the molding surface 32a is formed in the flat molding surface 32b.

The upper mold 33 also has a cylindrical shape. The upper mold 33 is fitted into the upper part of the sleeve 34. Further, the molding surface 33a at the center of the upper mold 33 is formed in, for example, a concave spherical shape or a concave aspherical shape. The outer periphery of the molding surface 33a is formed on a flat molding surface 33b.
The sleeve 34 has a cylindrical shape. The central axis of the sleeve 34 coincides with the mold center line OO. The upper mold 33 is slidably inserted in the axial direction of the sleeve 34 (the mold center line OO direction), that is, the vertical direction.

  In the present embodiment, the lower mold 32, the upper mold 33, and the sleeve 34 are finished by grinding and polishing a cemented carbide such as tungsten carbide (WC). The glass material 23 is a commercially available spherical optical glass. In the present embodiment, the glass material 23 is described as an example of the optical element material, but is not limited thereto. For example, a synthetic resin such as polycarbonate may be used.

FIG. 3 shows a cross-sectional view of a lens 35 as a molded optical element.
In FIG. 3, the molded lens 35 is obtained by disassembling the mold set 17 carried out of the molding chamber 14. This lens 35 is an optical lens whose optical function surfaces 35a and 35b are biconvex, and has a thin flange 35c on the outer periphery.

Next, FIG. 4 is a diagram showing an outline of the transmitted wavefront measuring apparatus 40.
With this transmitted wavefront measuring device 40, the optical performance of the molded lens 35 can be measured.
That is, the transmitted wavefront measuring apparatus 40 is an apparatus that uses the interference of light to capture interference fringes generated from the phase difference between the incident light and the emitted light of the lens to be measured, and to measure the transmitted wavefront aberration of the lens to be tested. . By using this transmitted wavefront measuring apparatus 40, it is possible to measure how much the transmitted wavefront obtained from the test lens is deviated from the transmitted wavefront obtained from a desired optical element.

The transmitted wavefront measuring apparatus 40 of the present embodiment is a combination of an interferometer 41 and a fringe analyzing apparatus 42 for analyzing interference fringes. The fringe analysis device 42 includes an image processing PC (personal computer) 43 and a display device 44.
The interferometer 41 includes a collimator lens 45 housed in the apparatus main body and a mirror 46 mounted on a mounting table 49 that can be raised and lowered, and uses laser light as a light source. The test lens 47 is disposed between the collimator lens 45 and the mirror 46.

When measuring the transmitted wavefront, a plane wave (parallel light) emitted from a light source (not shown) and transmitted through the collimator lens 45 enters the lens 47 to be examined. The light transmitted through the test lens 47 is folded back by the mirror 46. Then, the interference fringes 48 generated by the incident light and the light reflected by the mirror are displayed on the display device 44.
Thus, the difference between the interference fringes (not shown) when the test lens 47 is in the ideal state and the actually measured interference fringes 48 is the wavefront aberration of the test lens 47. By analyzing this wavefront aberration by the image processing PC 43, it is possible to measure with high accuracy how much the optical performance of the lens 47 to be tested is different from the design value.

In the present invention, molding the lens 35 using a temporary mold (mold) is referred to as a primary process (also referred to as primary processing). In the present invention, performing at least one of the centering process as the outer diameter process and the formation of the antireflection film on the molded lens 35 is referred to as a secondary process (also referred to as a secondary process). The secondary process does not include annealing.

[Embodiment 1]

Next, a method for manufacturing an optical element according to this embodiment will be described.
In the present embodiment, as an example of secondary processing, a case where centering processing (outer diameter processing) is performed will be described.

  FIG. 5 is a diagram showing a schematic configuration of the centering apparatus 50, and FIG. 6 is a cross-sectional view of the lens 36 after the centering process.

In FIG. 5, the centering device 50 includes holders 51 and 51 that hold the lens 35 from both sides in the optical axis direction, a diamond wheel 52 that polishes the lens 35, a supply pipe 53 that supplies a polishing liquid, have. Then, the outer peripheral portion is centered by the diamond wheel 52 that rotates while spraying the polishing liquid onto the lens 35.
The shape of the lens 35 shown in FIG. 5 is different from that shown in FIG. 3, but here, for the sake of convenience of explanation, it will be described as a lens having the same shape.

As shown in FIG. 6, the lens 36 after the centering process has a biconvex shape in which the outer peripheral part is processed concentrically with high accuracy around the optical axis center OO.
Next, FIG. 7 is a diagram showing a flowchart for correcting the provisional mold to determine the formal mold and producing the optical element using the formal mold.
First, in S (step) 1, a lens 35 as an optical element is molded using a temporary mold (the configuration is the same as that of the mold set 17 described above) (primary processing step). Here, the provisional mold refers to a mold that is cut and manufactured based on a design drawing. Note that it is not known at this time whether the optical performance of the lens 35 formed using this provisional mold is good or bad.

The molding of the lens 35 is performed using the optical element manufacturing apparatus 10 described above.
That is, the mold set 17 incorporating the glass material 23 is conveyed into the molding chamber 14, and the lens 35 is molded through the heating stage 20, the press stage 21, and the cooling stage 22. Since these steps have already been described, the description thereof is omitted here.

Next, in S2, secondary processing (centering processing) is performed on the molded lens 35 (secondary processing step).
Next, in S3, the measurement of the optical performance of the lens 36 after the secondary processing and the deviation from the design value are calculated (measurement process, calculation process). This is to determine whether or not the optical performance of the lens 36 matches the optical performance intended by the designer (whether or not it is OK). In the present invention, the design value can have an allowable range.

In this measurement of optical performance, the center thickness of the lens 36 is measured with a micrometer, the shape of the optical surface of the lens 36 is measured with a contact-type shape measuring machine, or the center of the lens 36 is refracted. The rate is measured using a refractometer or spectrometer. Furthermore, the refractive index distribution (radial nonuniformity) is measured by an oil-on-plate method or a polishing method.
The oil-on-plate method and the polishing method can be performed using a general interferometer. For example, a sample with good flatness is prepared as an object to be measured, and the refractive index distribution of the material of the sample is measured based on the wavefront of a light beam transmitted through the sample.

In S3, when the optical performance of the lens 36 is measured and does not match the design value (No), the process proceeds to S4 to perform provisional mold correction (mold correction) (mold manufacturing process). Return to.
The mold correction here is based on the measurement item of the optical performance of the lens 36 in S3, and the deviation from the design value is calculated so that the optical performance matches the design value after the secondary processing (after the secondary processing). This also means that the shape of the provisional mold is corrected by grinding or the like.

In S3, when the optical performance of the lens 36 is determined to match the design value (Yes), the process proceeds to S5 and the formal type is determined.
When the formal mold is determined, in S6, molding is performed with the formal mold (molding process) to obtain a formal lens. Further, in S7, secondary processing (centering processing) is performed on the official lens.

  Next, in S8, the optical performance of the formal lens is measured as described above. Here, it is determined whether or not the optical performance is an acceptable deviation from the design value. If Yes, the process proceeds to S9, and finally a good lens is obtained. If No, the lens is discarded. Note that the measurement of the optical performance in S8 is not for feeding back to the mold correction, but has a meaning of determining the quality of the lens.

According to the present embodiment, the optical performance of the lens 36 is measured after the secondary processing such as the centering processing, and the provisional type correction is performed based on the measurement result. It is possible to design a mold in consideration of a change in refractive index distribution and surface shape (change in optical performance). By molding the optical element using the formal mold thus obtained, a large amount of formal lenses satisfying the desired optical performance can be obtained.
[Embodiment 2]

The present embodiment is different from the first embodiment in that the optical performance is measured twice before the formal type is determined from the provisional type.
In addition, the same code | symbol is attached | subjected to the member which is the same as that of Embodiment 1, or is equivalent, and the description is abbreviate | omitted. The contents defined in Embodiment 1 are also used in the same meaning in this embodiment.
In this embodiment, a case where a thin film (antireflection film) is formed will be described as an example of secondary processing.

FIG. 8 is a diagram showing an outline of the thin film forming apparatus 60.
With this thin film forming apparatus 60, a thin film can be formed on the lens 35 as a secondary process.
In FIG. 8, a thin film forming apparatus 60 includes a vacuum chamber 61, a raw material (vapor deposition material) 63 placed on a heating plate 62 in the vacuum chamber 61, and a lens 35 supported by a holder 64 above the vacuum chamber 61. And a heater 65 disposed above the lens 35.
In the present embodiment, an antireflection thin film is formed on the lens 35 by vacuum deposition. This vacuum deposition is performed by heating and evaporating a metal, a compound, or the like in vacuum and forming the vapor in a thin film on the surface of the object.

In the present embodiment, the raw material 63 is heated and evaporated, and the vapor is attached to one optical surface of the lens 35 to form a thin film.
FIG. 9 is a diagram illustrating a flowchart for determining a formal type from the provisional type according to the second embodiment and producing an optical element using the formal type.
The present embodiment is different from the first embodiment in that the optical performance is measured before and after the secondary processing (S12, S14) in the provisional correction flow and the optical performance is measured. .
First, in S11, a lens 35 as an optical element is molded using a temporary mold (primary processing step). The lens 35 is molded using the optical element manufacturing apparatus 10 described above. Since the manufacturing process has already been described, the description thereof is omitted here.

Next, in S12, the first optical performance of the molded lens 35 is measured (first measurement step).
In the measurement of the optical performance here, the optical performance of the lens is comprehensively measured using the transmission wavefront measuring device 40 described above. For example, in the measurement of the refractive index distribution, depending on the oil-on-plate method or the polishing method, it is necessary to process the lens 35 to be inspected into the shape of the measurement sample.
For this reason, a change in the refractive index distribution may occur here, and it is difficult to measure accurately. On the other hand, if the transmitted wavefront measuring apparatus 40 is used, measurement can be performed without processing the lens 35, so that accurate measurement can be performed.

Furthermore, if the transmitted wavefront measuring apparatus 40 is used, it can be evaluated as a comprehensive performance including all influences such as the surface shape of the lens 35 and the refractive index distribution, and the number of measurement items can be reduced.
Since the measurement principle by the transmitted wavefront measuring device 40 has already been described, the description thereof is omitted here.

Next, in S13, secondary processing (formation of an antireflection film) is performed (secondary processing step).
Next, in S40, the second optical performance of the lens 36 after the thin film is formed on the lens 35 is measured (measurement step). The optical performance is measured using the transmitted wavefront measuring device 40.
Next, in S14, the deviation from the design value is calculated based on the result of the second optical performance measurement S40 (calculation step). As a result, when it does not agree with the design value (No), the process proceeds to S15 to perform provisional type correction (type correction), and returns to S11.

In this embodiment, by measuring the optical performance of the lens 35 at S12, the difference between the lens 36 after the secondary processing (S13) and the measurement result of the optical performance at S14 is compared. Can do. By using this comparison data, for example, in order to obtain a good product type (formal product), the measured value (S12) of the optical performance of the lens 35 molded with the provisional die should be within a certain range. It is possible to predict whether a formal mold capable of molding the lens 36 can be obtained.
Thus, in the mold correction in S15, the deviation from the design value is calculated based on the measurement item of the optical performance in S12 so that the optical performance matches the design value after the secondary processing (the change after the secondary processing is also In view of this, the shape of the provisional mold can be corrected by grinding or the like. Therefore, after obtaining the comparison data, after the first optical performance measurement (S12), the secondary processing (S13) and the second optical performance measurement (S40) are not performed (broken arrows in FIG. 9). A), it can be determined whether or not the deviation between the optical performance of the lens 35 and the design value is allowed (S14).

It is preferable that a large number of the comparison data is accumulated. This makes it more reliable to estimate the necessary correction amount and correction location of the provisional type only by looking at the optical performance measurement result in S12. The comparison data may be obtained from actual measurement values or may be obtained from simulation. Further, the number of samples (n number) for obtaining one comparison data can be set as appropriate.
In S14, when the optical performance of the lens 36 after the secondary processing is measured and the design value is matched (Yes), the process proceeds to S16 and the formal type is determined.
Next, in S17, the lens 35 is molded by this formal mold (molding process).
Further, in S13 ′, secondary processing (formation of an antireflection film) similar to S13 described above is performed (secondary processing step).

Next, in S18, the optical performance of the molded lens 35 is measured. In the measurement of the optical performance here, the optical performance is comprehensively measured using the transmission wavefront measuring apparatus 40 described above. Here, it is determined whether or not the optical performance is an allowable deviation from the design value. If Yes, the process proceeds to S19 to obtain a good lens. If No, the lens 35 is discarded.
Thus, in S19, a good lens 35 after the optical performance is measured can be obtained.

  According to the present embodiment, the optical performance of the lens is measured before and after the secondary processing, and the difference is compared, so that the measured value of the optical performance of the lens 35 formed by the provisional mold is within what range. Then, it can be predicted whether a formal mold capable of molding a good lens 36 can be obtained. Therefore, it is possible to reduce the man-hours until the formal mold is obtained.

Note that the change in optical performance due to the centering (secondary processing) of the lens is caused by the release of stress (refractive index distribution) inside the lens. Therefore, if the internal stress of the lens is released in advance by performing an annealing process before the centering process, the optical performance does not change due to the centering process.
However, in the formation (secondary processing) of a thin film (antireflection film), it is considered that the change in optical performance occurs when the lens is heated during the formation of the thin film. Therefore, even in the lens subjected to the annealing treatment (no internal stress), the optical performance can be changed by the secondary processing, but according to the present embodiment, the optical performance after the secondary processing or Since the mold correction is performed in consideration of the change in the optical performance due to the secondary processing, the problem can be solved.
[Embodiment 3]

FIG. 10 is a diagram showing a flowchart for determining a formal type from a provisional type and mass-producing optical elements using the formal type.
In addition, the same code | symbol is attached | subjected to the member which is the same as that of Embodiment 1, or is equivalent, and the description is abbreviate | omitted. The contents defined in Embodiment 1 are also used in the same meaning in this embodiment.

In the present embodiment, a step (S26, S27, S29, S30, S32) for calculating the amount of change before and after the secondary processing of the lens molded with the formal mold and obtaining comparison data is added, and in the mass production stage. The molding by the formal mold is different from the first and second embodiments in that the measurement of the optical performance after the secondary processing is omitted.
First, in S21, the lens 35 as an optical element is molded using a temporary mold (primary processing step). This molding is performed using the optical element manufacturing apparatus 10 described above. Description of the manufacturing process is omitted.

Next, in S22, secondary processing of the molded lens 35 is performed (secondary processing step). The secondary processing here is, for example, the formation of a thin film (antireflection film).
The method for forming this thin film (antireflection film) is as described in FIG.
In S23, the optical performance of the lens 36 after the secondary processing is measured and the deviation from the design value is calculated, and it is determined whether the design value is met (whether it is OK) (measurement process, calculation process). . In the measurement of the optical performance here, the optical performance can be comprehensively measured by the transmitted wavefront measuring device 40.

If the optical performance measurement result does not match the design value in S23 (No), the process proceeds to S24 to perform temporary mold correction (mold correction) (mold manufacturing process). Return to S21. In this mold correction, the deviation from the design value is calculated based on the measurement item of the optical performance in S23 so that the optical performance matches the design value after the secondary processing (based on the change after the secondary processing). The shape of the temporary mold is corrected by grinding or the like.
If the optical performance measurement matches the design value (Yes) in S23, the process proceeds to S25 and the formal type is determined.

Next, in S26, the lens 35 is preformed using this formal mold (molding process).
Subsequently, after measuring the third optical performance of the preformed lens 35 in S27, a thin film (antireflection film) is formed by secondary processing in S29 (preliminary secondary processing step). In S30, the fourth optical performance of the lens 36 after the secondary processing is measured. The amount of change in the optical performance of the lens 36 due to the secondary processing can be grasped by the difference in the measurement results of the optical performance in S27 and S30, and comparison data can be acquired. Note that the acquisition and use of comparison data is the same as that described in the second embodiment, and thus detailed description thereof is omitted.
According to the present embodiment, by measuring the optical performance of the lens 36 before and after the secondary processing (S29), it is possible to grasp the amount of change in the optical performance due to the secondary processing. Thereby, the quality determination of the product can be performed before performing the secondary processing in the mass production stage (the quality determination after the secondary processing can be omitted).

That is, the process (mass production stage) in the direction shown by the broken line in FIG. 10 is realized.
In the mass production stage, first, in S26 ′, the lens 35 is molded using a formal mold (molding process).
Next, in S30 ′, the optical performance of the molded lens 35 is measured. In the measurement of the optical performance here, the optical performance is comprehensively measured by the transmitted wavefront measuring device 40. Next, the optical performance after the secondary processing is predicted based on the measurement result of the optical performance and the above-described comparison data, and it is determined whether or not the predicted optical performance is an allowable deviation from the design value (S27 ′). . As a result, if Yes, the process proceeds to S28 'to obtain a good lens 35. Further, thereafter, a thin film (antireflection film) is formed on the molded lens 35 by secondary processing. In S27 ′, if No, the lens is discarded.

According to the present embodiment, in the molding by the formal mold at the stage of mass production, after the good lens 35 (S28 ′) is obtained, secondary processing such as formation of a thin film (antireflection film) is performed. It is possible to prevent the flow to the secondary processing and to reduce useless man-hours.
Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, the second embodiment and the third embodiment can be combined.

DESCRIPTION OF SYMBOLS 10 Optical element manufacturing apparatus 11 Heat insulation plate 12 Housing | casing 13 ₁ Holding member 13 ₂ Holding member 13 ₃ Holding member 14 Molding chamber 15 Carry-in shutter 16 Carry-out shutter 17 Mold set 18 Base block 19 Base block 20 Heating stage 21 Press stage 22 Cooling Stage 23 Glass material 24 ₁ Upper plate 24 ₂ Upper plate 24 ₃ Upper plate 25 ₁ Lower plate 25 ₂ Lower plate 25 ₃ Lower plate 26 ₁ Air cylinder 26 ₂ Air cylinder 26 ₃ Air cylinder 27 ₁ Acting rod 27 ₂ Acting rod 27 ₃ actuating rod 28 ₁ on the cartridge heater 28 _second upper cartridge heaters 28 ₃ above the cartridge heater 29 ₁ under the cartridge heater 29 ₂ under the cartridge heaters 29 ₃ under the cartridge heater 30 control device 31 intermediate lens 32 lower mold 32a forming 32b forming surface 33 upper mold 33a forming surface 33b forming surface 34 the sleeve 35 lens 35a optically functional surface 35b optical function surface 35c flange portion 36 the lens 40 transmitted wavefront measuring apparatus 41 interferometer 42 fringe analysis apparatus 43 image processing PC
44 Display device 46 Mirror 47 Test lens 48 Interference fringe 49 Mounting table 50 Centering device 51 Holder 52 Diamond wheel 53 Supply pipe 60 Thin film forming device 61 Vacuum chamber 62 Heating plate 63 Raw material 64 Holder 65 Heating heater

Claims (4)

A primary process of forming an optical element material using a temporary mold;
A secondary step of performing at least one of outer diameter processing and formation of an antireflection film on the optical element molded in the primary step;
Measuring the optical performance of the optical element after the secondary step;
A calculation step of calculating a deviation between the measured optical performance of the optical element and a design value;
When the calculated deviation is allowed, determining the provisional type as a formal type; and
A molding process for molding the optical element material using the determined formal mold,
When the deviation calculated by the calculation step is not allowed, the method of manufacturing an optical element is characterized by repeating the correction of the provisional mold and returning to the primary step until the deviation is allowed. In the manufacturing method of the optical element according to claim 1,
Furthermore, before the secondary step, it has a first measurement step of measuring the optical performance of the optical element molded in the primary step,
A method of manufacturing an optical element, wherein a change in optical performance due to the secondary process is calculated from a measurement result of the first measurement process and a measurement result of optical performance of the optical element after the secondary process. . In the manufacturing method of the optical element according to claim 1 or 2,
Furthermore, before the molding step,
A step of preforming an optical element material using the formal mold;
A third measuring step for measuring the optical performance of the preformed optical element;
After the third measurement step, a preliminary secondary step of performing at least one of outer diameter processing and antireflection film formation on the optical element;
A fourth measuring step for measuring the optical performance of the optical element after the preliminary secondary step,
A method of manufacturing an optical element, wherein a change in optical performance due to the preliminary secondary process is calculated from a measurement result of the third measurement process and a measurement result of the fourth measurement process. In the manufacturing method of the optical element in any one of Claims 1 thru | or 3,
The change in the optical performance is due to a change in at least one of a refractive index distribution and a surface shape of the optical element,
The method of manufacturing an optical element, wherein the measurement of the optical performance is performed using a transmission wavefront measurement method.