JP4232380B2 - Method for manufacturing composite optical element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a method for producing a composite optical element having a resin optical layer.InRelated.
[0002]
[Prior art]
As one of optical elements, there is a composite optical element in which two layers having different optical actions are brought into close contact with each other to improve the function.
Some phase-type diffractive optical elements (zone plates, diffraction gratings) have, for example, a resin-made optical layer formed on a glass optical layer having a phase-type diffractive surface on the surface.
[0003]
The optical layer made of glass is a layer made of optical glass (crown glass, quartz glass, fluorite, etc.) whose boundary surface with an adjacent medium functions as an optical surface (hereinafter simply referred to as “glass”). Layer "), an optical layer made of resin, an optical resin (polycarbonate, polystyrene, polymethacrylic acid, acrylic resin, urethane resin, epoxy resin) whose boundary surface with an adjacent medium functions as an optical surface. A layer made of resin, etc. (hereinafter simply referred to as “resin layer”).
[0004]
In addition, since the resin layer is not formed and bonded after being formed separately from the glass layer, it is formed directly by applying a liquid resin on the glass layer and solidifying, so that the diameter is the outer diameter of the glass layer. Generally, it is set to be slightly smaller.
FIG. 7 is a diagram illustrating a procedure for forming the resin layer 11 of the composite optical element. Hereinafter, an example in which the composite optical element has a two-layer structure of a resin layer and a glass layer will be described.
[0005]
Prepare a glass substrate 10 (in this case, it has a phase-type diffractive surface 10a on the surface) that has been molded in advance to function as a glass layer (FIG. 7 (a)). An uncured product 11 ′ of optical resin is applied (FIG. 7B).
At this time, the uncured product 11 ′ has not yet spread all over the concave and convex portions of the diffractive surface 10 a.
[0006]
Here, the application amount of the uncured product 11 ′ is determined according to the design value t of the thickness of the resin layer 11, the design value D of the diameter, and the curing shrinkage rate α of the uncured product 11 ′.
Thereafter, the mold 13 (FIG. 7C) is applied to the uncured product 11 'from the surface 11a side, and the uncured product 11' is spread (FIG. 7D).
The mold 13 is a metal or the like whose surface that comes into contact with the uncured material 11 ′ is processed in advance into an inverted shape to be applied to the surface 11 a of the resin layer 11.
[0007]
The distance d between the mold 13 and the substrate 10 is kept at the design value t of the thickness of the resin layer 11.
In addition, the code | symbol 12 of FIG.7 (c) is a jig | tool which supports the glass substrate 10 from the periphery.
In this state, curing heat or light is applied to the uncured product 11 ′, and the uncured product 11 ′ contracts in the radial direction.
[0008]
The thickness and diameter of the uncured product 11 ′ (resin layer 11) after curing become the respective design values t and D, and the composite optical element 1 is completed. Thereafter, the composite optical element 1 is released (FIG. 7E).
[0009]
[Problems to be solved by the invention]
However, in the completed composite optical element 1, bubbles are mixed in the vicinity of the diffractive surface 10a of the resin layer 11 (the bottom of the unevenness), or undulation occurs on the surface 11a of the resin layer 11, Desired optical characteristics may not be obtained.
[0010]
In addition, an error may occur in the diameter of the resin layer 11, but in general, an error in the size of the optical element in the radial direction is acceptable when compared with an error in the size of other parts (for example, thickness). May become defective.
For example, if the resin diameter becomes too large and exceeds the diameter of the glass substrate 10, the end surface 11b of the resin layer 11 may not be smooth, and the composite optical element 1 becomes defective or the end surface 11b. In some cases, an extra process is required to prepare the image. Conversely, if the resin diameter is too small and smaller than the effective diameter, the optical element cannot obtain desired optical characteristics.
[0011]
The problems as described above worsen the yield of forming the resin layer 11, and consequently worsen the yield of the composite optical element 1.
In order to improve the yield, the above-mentioned problems are eliminated in the apparatus used for forming the resin layer 11 (such as a molding machine used in the steps of FIGS. 7C and 7D) and the material of the resin layer 11. Although some ideas can be considered, they all require development costs.
[0012]
  Therefore, if the yield can be improved by devising the design stage of the composite optical element 1, it is preferable because it is inexpensive. Therefore, the present invention provides a method for manufacturing a composite optical element that can increase the yield without changing the method of forming a composite optical element having a resin layer.TheThe purpose is to provide.
[0015]
[Means for Solving the Problems]
  Of the present inventionMethod for manufacturing composite optical elementOne aspectIsOn the first optical layer made of an optical material, an uncured product of resin, which is a material of the second optical layer made of resin, is set according to the thickness of the second optical layer and the design value of the formation range. Supplying a mold, applying a mold, and maintaining a distance between the mold and the first optical layer at a design value t of the thickness of the second optical layer; and uncured with the mold applied A method for producing a composite optical element, comprising: a curing step of curing an object to fix the second optical layer on the first optical layer,The design value t of the thickness of the second optical layer includes the design value D of the diameter of the second optical layer, the maximum error amount Δdmax of the positioning of the gap, and the maximum of the diameter of the second optical layer. With respect to the allowable error amount ΔDmax, ΔDmax ≧ | Dt^0.5((T ± Δdmax)^-0.5-T^-0.5) | Is determined to satisfy the expression.
[0017]
  Of the present inventionMethod for manufacturing composite optical elementOne aspectIsOn the first optical layer made of the optical material, an uncured product of the resin that is the material of the second optical layer made of resin, the design value of the thickness and formation range of the second optical layer, and the resin A mold application step for supplying the mold in accordance with the curing shrinkage rate, and a mold application process for maintaining the distance between the mold and the first optical layer at the design value t of the thickness of the second optical layer; A curing process for curing the uncured product in a contact state and fixing the second optical layer on the first optical layer,The design value t of the thickness of the second optical layer is the maximum allowable amount Dmax of the diameter of the uncured material, the maximum error amount Δdmax of the positioning of the interval, and the design value of the diameter of the second optical layer. Dmax ≧ (D + (Dt) with respect to D and the curing shrinkage α (%) of the resin^0.5((T-Δdmax)^-0.5-T^-0.5)) / ((1-0.01α)^1/3) To satisfy the formula (1).
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
  [First Embodiment]
  1 and 2The first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram for explaining a design method of the composite optical element 1 of the present embodiment. The composite optical element 1 to be designed in this embodiment has a glass layer and a resin layer in close contact with each other. Hereinafter, a two-layer structure in which the resin layer 11 is formed on the glass substrate 10 is adopted. At least the resin layer 11 is formed by a method similar to that of the conventional example shown in FIG. 7 (refer to the fourth embodiment for details). In addition, a phase type diffraction surface 10 a is formed on the surface of the glass substrate 10 (boundary surface between the glass substrate 10 and the resin layer 11).
[0022]
The parameters to be determined in the design of the composite optical element 1 include the uneven step (grating height) of the diffraction surface 10a, the thickness and diameter of the glass substrate 10, and the thickness and diameter of the resin layer 11. .
Conventionally, the conditions considered at the time of designing are mainly the conditions for satisfying the user's required specifications, and the conditions for improving the production yield of the composite optical element 1 were not included ( The materials of the resin layer 11 and the glass substrate 10 were sometimes optimized in order to improve the yield, but at least the thickness and the diameter were not so optimized.
[0023]
In the conventional example, as a factor that deteriorates the yield, bubbles are mixed in the vicinity of the diffractive surface 10a of the resin layer 11 or waviness is generated on the surface 11a of the resin layer 11.
Therefore, the design condition of the present embodiment is that “at the time of forming the resin layer 11, bubbles are not mixed in the vicinity of the bottom of the unevenness of the diffraction surface 10 a and the undulation of the surface 11 a of the resin layer 11 is sufficiently small. "Condition for".
[0024]
FIG. 2 is a diagram showing experimental results obtained by examining the presence or absence of bubbles and the change in the amount of undulation when the design value t of the thickness of the resin layer 11 is changed.
In the experiment, the composite optical element 1 was formed by changing the design value t of the thickness of the resin layer 11 to 30 μm, 60 μm, 75 μm, and 90 μm. At this time, the design value of the uneven step (grating height) h of the diffractive surface 10a was set to a constant value of 15 μm.
[0025]
In each formation, the coating amount of the uncured product 11 ′ (see FIG. 7B) and the distance d between the glass substrate 10 and the mold 13 (see FIG. 7D) are all the thickness of the resin layer 11. The conventional design value t, the design value D of the diameter of the resin layer 11, and the curing shrinkage rate α of the uncured product 11 ′ were set in the same manner as in the prior art.
The waviness index was a PV value (Peak to Valley) obtained by actually measuring the surface shape of the surface 11a of the resin layer 11 after formation. The larger the PV value, the greater the swell.
[0026]
As apparent from FIG. 2, as the ratio (t / h) of the thickness t of the resin layer 11 to the lattice height h increases from 2 → 4 → 5 → 6, bubbles disappear and undulations decrease. .
The reason is considered as follows.
In the state immediately before the uncured product 11 ′ is cured (see FIG. 7D), the portion of the diffractive surface 10a where the height of the diffractive surface 10a changes abruptly (cliff portion) has a sharp thickness of the uncured product 11 ′. It has changed. When the uncured product 11 ′ is contracted by irradiation with heat or light for curing, a greater stress is generated in the portion where the thickness is abruptly changed in the uncured product 11 ′ than in the other portion. . Such non-uniform stress causes bubbles in the resin layer 11 or undulations on the surface 11 a of the resin layer 11.
[0027]
However, according to FIG. 2, particularly when the ratio (t / h) is 5 or more, there are no bubbles, and the undulation is suppressed to 5.0 (μm) or less (sufficiently within an allowable range). You can see that
Therefore, “t ≧ 5h” is added as a condition for designing the present embodiment. By so doing, the mixing of bubbles into the resin layer 11 and the occurrence of undulations on the surface 11a are reliably suppressed, so that the yield of forming the resin layer 11 is improved.
[0028]
In addition, what is necessary is just to add with respect to the design value t of thickness about this condition (t> = 5h) for improving a yield, satisfy | filling the conditions for satisfy | filling a user's requirement specification.
As described above, according to the design method of the present embodiment, the yield of formation of the resin layer 11 is increased despite no change in the formation method of the resin layer 11.
[0029]
  [Second Embodiment]
  3 and 4A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram for explaining a design method of the composite optical element 1 of the present embodiment. The composite optical element 1 to be designed in this embodiment has a glass layer and a resin layer in close contact with each other. Hereinafter, a two-layer structure in which the resin layer 11 is formed on the glass substrate 10 is adopted. At least the resin layer 11 is formed by a method similar to that of the conventional example shown in FIG. 7 (refer to the fourth embodiment for details).
[0030]
As described in the conventional example, the error ΔD generated in the actual diameter <D> (design value D) of the resin layer 11 greatly affects the characteristics of the composite optical element 1. It is a factor that deteriorates the yield.
Therefore, the design condition of the present embodiment is that “the magnitude of the error ΔD occurring in the actual diameter <D> (design value D) of the resin layer 11 | ΔD | is the maximum allowable error amount ΔDmax (ΔDmax> 0). ) A condition (| ΔD | ≦ ΔDmax) ”for ensuring the following is added. The maximum allowable error amount ΔDmax is determined according to the user's required specifications.
[0031]
Also in this embodiment, it is considered that a specific condition is added to the design value t of the thickness of the resin layer 11.
FIG. 4 is a diagram illustrating a state when the resin layer 11 is formed (when the uncured material 11 ′ is cured).
As described above, the set value d of the distance between the glass substrate 10 and the mold 13 when the uncured product 11 ′ is cured is the design value t of the thickness of the resin layer 11, and the actual thickness <t> is It can be assumed that the actual interval <d> matches (d = t, <d> = <t>).
[0032]
However, the actual interval <d> does not always coincide with the set value d. This is because an error (positioning error) Δd occurs in positioning the distance between the glass substrate 10 and the mold 13.
Therefore, the thickness error Δt of the resin layer 11 coincides with the positioning error Δd between the glass substrate 10 and the mold 13 (formula (1)).
[0033]
Δt = Δd (1)
On the other hand, the actual volume <V> (= π <t> (<D> / 2) of the resin layer 11 (see FIG. 3) of the completed composite optical element 1)²) Is its ideal value V (= πt (D / 2)²).
This is because the actual volume <V> is determined by the application amount of the uncured material 11 ′ on the glass substrate 10, and the application amount is determined by the design value t of the thickness of the resin layer 11 and the design of the diameter of the resin layer 11. This is because it can be controlled with sufficiently high accuracy according to the value D and the curing shrinkage rate α of the uncured product 11 ′.
[0034]
Therefore, Equation (2) is established between the actual diameter <D> and the actual thickness <t>.
V = π <t> (<D> / 2)²    ... (2)
Then, in equation (2), from the amount of change in <D> when <t> is changed from t to (t + Δt), the error ΔD of the diameter (design value D) of the resin layer 11 is expressed by equation (3). Is obtained as follows.
[0035]
ΔD = 2 (V / π)^0.5((T + Δt)^-0.5-T^-0.5(3)
Formula (1), Formula (3), and V = πt (D / 2)²Based on the above, the diameter error ΔD of the resin layer 11 can be expressed by the thickness design value t, the diameter design value D, and the positioning error Δd as shown in Expression (4).
ΔD = Dt^0.5((T + Δd)^-0.5-T^-0.5(4)
As described above, in order to ensure that the magnitude | ΔD | of the diameter error ΔD of the resin layer 11 is within the maximum allowable error amount ΔDmax, the magnitude | Δd | of the positioning error Δd is 0 to the maximum. In any case of the error amount Δdmax (Δdmax> 0), the magnitude | ΔD | of the error ΔD must be within the maximum allowable error amount ΔDmax.
[0036]
Based on Expression (4), the conditional expression for that is Expression (5).
ΔDmax ≧ | Dt^0.5((T ± Δdmax)^-0.5-T^-0.5) | (5)
Therefore, in the present embodiment, the design value t of the thickness of the resin layer 11 may satisfy the condition represented by the formula (5).
In this case, the magnitude | ΔD | of the diameter error ΔD of the resin layer 11 is surely kept below the allowable error amount ΔDmax, so that the manufacturing method of the composite optical element 1 is not changed at all. Therefore, the yield of forming the resin layer 11 is increased.
[0037]
  Note that the maximum error amount Δdmax of the positioning error Δd is specific to the molding machine used for forming the resin layer 11 and can be measured in advance.
  [Third Embodiment]
  5 and 6The third embodiment of the present invention will be described with reference to FIG..
[0038]
FIG. 5 is a diagram for explaining a design method of the composite optical element 1 of the present embodiment.
The composite optical element 1 to be designed in this embodiment has a glass layer and a resin layer in close contact with each other. Hereinafter, a two-layer structure in which the resin layer 11 is formed on the glass substrate 10 is adopted. At least the resin layer 11 is formed by a method similar to that of the conventional example shown in FIG. 7 (refer to the fourth embodiment for details).
[0039]
As described in the conventional example, the defective shape of the end face 11b of the resin layer 11 causes the composite optical element 1 to be a defective product or requires an extra step, so that the yield of the composite optical element 1 is deteriorated. Is a factor.
Therefore, “conditions for reliably suppressing the shape defect of the end surface 11b of the resin layer 11” are added to the design conditions of the present embodiment.
[0040]
Also in this embodiment, it is considered that a specific condition is added to the design value t of the thickness of the resin layer 11.
FIG. 6 is a diagram illustrating a state when the resin layer 11 is formed (immediately before the uncured material 11 ′ is cured).
The glass substrate 10 is supported by the jig 12 from below the outer peripheral portion, and the mold 13 is pressed against the uncured material 11 ′ from the surface 11a ′ side (however, the distance d between the mold 13 and the glass substrate 10). Is kept at the design value t of the thickness of the resin layer 11).
[0041]
The defective formation of the end face 11b of the resin layer 11 is that the actual diameter <D ′> of the uncured product 11 ′ at this time is larger than the maximum allowable amount Dmax (Dmax> 0), and the uncured product 11 ′ It occurs when it contacts 12 or overflows from the jig 12.
Therefore, in order to reliably suppress formation defects,
Dmax ≧ <D ′> (6)
Must.
[0042]
In general, the maximum allowable amount Dmax is 1.6 mm smaller than the outer diameter A of the glass substrate 10 due to the structure of the jig 12, and Dmax = A−1.6 mm.
Here, the actual diameter <D ′> of the uncured product 11 ′ is a value before curing shrinkage of the actual diameter <D> of the resin layer 11.
If the curing shrinkage (volume shrinkage) of the uncured product 11 ′ is α (%) and the shrinkage in the thickness direction is ignored, the diameter <D> after curing is the diameter <D ′> before curing. (1-0.01α)^1/3Because it doubles
<D> = (1-0.01α)^1/3<D '> (7)
Holds. Therefore, Expression (9) is established from Expression (8).
[0043]
D + ΔD = (1−0.01α)^1/3<D '> (8)
<D '> = (D + ΔD) / ((1-0.01α)^1/3(9)
From equation (9), equation (6) is expressed as equation (10).
Dmax ≧ (D + ΔD) / ((1-0.01α)^1/3(10)
Here, ΔD (error in the diameter of the resin layer 11) in the right side of the equation (10) is determined by the positioning error Δd and the thickness design value t, as in equation (4) of the second embodiment. Therefore, Formula (10) is represented by Formula (11).
[0044]
Dmax ≧ (D + (Dt^0.5((T + Δd)^-0.5-T^-0.5)) / (1-0.01α)^1/3(11)
In order to surely suppress the formation failure, the equation (11) must be satisfied when the magnitude | Δd | of the positioning error Δd is any of 0 to the maximum error amount Δdmax (Δdmax> 0). I must. The other conditional expression is expression (12).
[0045]
Dmax ≧ (D + (Dt^0.5((T ± Δdmax)^-0.5-T^-0.5)) / (1-0.01α)^1/3(12)
Moreover, Formula (12) can be simplified like Formula (13).
Dmax ≧ (D + (Dt^0.5((T-Δdmax)^-0.5-T^-0.5)) / (1-0.01α)^1/3(13)
This is because the uncured resin 11 ′ may come into contact with the jig 12 or overflow from the jig 12, and the formation failure may occur when the error Δd of the interval d becomes negative (Δdmax in Expression (12)). This is because only when the sign given to “-” is “−”.
[0046]
Therefore, in the present embodiment, the condition represented by Expression (13) may be satisfied with respect to the design value t of the thickness of the resin layer 11.
By doing so, the shape of the end surface 11b of the resin layer 11 is surely good, so that the yield of the formation of the resin layer 11 is increased despite no change in the method of forming the resin layer 11.
[0047]
  Note that the maximum error amount Δdmax of the positioning error Δd is specific to the molding machine used for forming the resin layer 11 and can be measured in advance.
  [Fourth Embodiment]
  A fourth embodiment of the present invention will be described..
[0048]
In the present embodiment, the composite optical element 1 is manufactured by applying the design method of each of the above embodiments. The composite optical element 1 having a two-layer structure of a glass layer and a resin layer and having a phase type diffractive surface at the boundary surface is manufactured here.
The manufacturing procedure includes the following steps (1), (2), (3), (4), (5), and (6). Step (3) and subsequent steps are the same as in the conventional example, and will be described with reference to FIG.
[0049]
(1) The glass substrate 10 and the resin layer 11 of the composite optical element 1 are designed.
In addition, the glass substrate 10 and the resin layer 11 are shape | molded circularly in the surface direction like other optical elements. Moreover, since the resin layer 11 is directly formed on the glass substrate 10 (from step (3)), the diameter thereof is set slightly smaller than the outer diameter of the glass substrate 10.
[0050]
The parameters to be determined in this design include the thickness and diameter of the glass substrate 10, the thickness and diameter of the resin layer 11, the uneven step (lattice height) of the diffraction surface 10a, and the like.
However, in this embodiment, any or all of the design methods of the first embodiment, the second embodiment, and the third embodiment are applied to this design.
(2) Based on the parameters determined in the step (1), the glass substrate 10 having the phase type diffraction surface 10a is formed (details will be described later).
[0051]
As a material of the glass substrate 10, crown glass, quartz glass, fluorite, and other optical glasses can be used.
(3) On the diffractive surface 10a of the glass substrate 10, an uncured resin 11 ', which is a material of the resin layer 11, is applied (see FIG. 7B).
As a material of the resin layer, in addition to polycarbonate, polystyrene, polymethacrylic acid, etc., acrylic resin, urethane resin, epoxy resin, and other optical resins can be used.
[0052]
The coating amount of the uncured product 11 ′, etc. includes the design value t of the thickness of the resin layer 11 determined in the step (1), the design value D of the diameter, and the curing shrinkage α (uncured) of the uncured product 11 ′. It is determined in the same manner as in the prior art.
(4) The mold 13 is applied to the uncured material 11 ′ from the surface 11 a ′ side, and the uncured material 11 ′ is spread to the bottom of the unevenness of the diffractive surface 10 a (see FIG. 7D). At this time, the distance d between the mold 13 and the substrate 10 is kept at the design value t of the thickness of the resin layer 11.
[0053]
In FIG. 7, the mold 13 has a flat surface that contacts the uncured material 11 ′. However, for example, when the surface 11 a of the resin layer 11 is to be a convex surface having a curvature r, a concave surface having a curvature r is provided. A pre-processed mold may be used.
(5) Heat or light for curing is applied to the uncured product 11 ′ while keeping the distance d at the design value t of thickness.
[0054]
(6) The composite optical element 1 in which the resin layer 11 is formed on the substrate 10 is completed and released (FIG. 7E).
In addition, shaping | molding (process (2)) of the glass substrate 10 is performed by either of following (A) (B) (C), for example.
(A) The surface of the optical glass that is the material of the glass substrate 10 is subjected to machining such as cutting to form irregularities on the diffraction surface 10a. (B) A resist layer finely processed by photolithography is formed on the glass surface on the surface of the optical glass that is the material of the glass substrate 10, and then the pattern shape of the resist layer is transferred by ion etching to form the diffraction surface 10a. Mold the irregularities. (C) The optical glass that is the material of the glass substrate 10 is softened and then pressed into a concavo-convex shape of the diffractive surface 10a by pressing a mold having a concavo-convex forming surface on the surface (so-called glass) Mold method.)
[0055]
In the present embodiment, part or all of the design of the resin layer 11 in the step (1) may be performed after the molding of the glass substrate 10 (step (2)).
[Others]
In each figure, each optical surface of the composite optical element is a flat surface (or an uneven surface formed on the flat surface), but may be a curved surface (a concave or convex spherical surface, a rotationally symmetric aspheric surface).
[0056]
In each embodiment, the optical layer to be in close contact with the resin layer is a glass layer, but an optical layer made of any material may be used as long as it has different characteristics from the resin layer.
Moreover, in 2nd Embodiment and 3rd Embodiment, although the boundary surface of a resin layer and a glass substrate was made into the diffraction surface (uneven surface), it is good also as a smooth surface (curved surface or plane).
[0057]
In each embodiment, each optical surface of the resin layer and the glass substrate is a transmission surface, but any one of the surfaces may be a reflection surface.
[0058]
【Example】
[First embodiment]
A plurality of diffractive optical elements each having a resin layer made of an optical resin on a glass substrate made of optical glass and having a phase type diffractive surface at the boundary surface between them were produced.
[0059]
The diffraction surface has a grating height h of 15 μm and a grating pitch P of 200 μm.
Further, an uncured UV curable resin was used as the optical resin, and curing was performed by UV irradiation.
In this example, the design value t of the resin layer thickness was set to 100 μm. Since this is 5 times or more of the lattice height h, the conditional expression (t / h ≧ 5) described in the first embodiment is satisfied.
[0060]
Actually, when the surface of the resin layer of each manufactured product was measured, no swell was observed in most of the manufactured products, and air bubbles were not mixed.
For comparison, when the design value t of the resin layer thickness was set to 50 μm, which was smaller than 5 times the lattice height h, a manufactured product in which both swells and bubbles were generated was found.
[0061]
[Second Embodiment]
In the same manner as in the first example, a plurality of diffractive optical elements having a resin layer made of optical resin on a glass substrate made of optical glass and having a phase type diffractive surface at the boundary surface between them were prepared. From the required specifications for this diffractive optical element, the tolerance ΔDmax of the diameter of the resin layer was 1.0 mm. Further, the maximum amount Δdmax of positioning error between the glass substrate and the mold at the time of molding the resin layer was 4 μm.
[0062]
In this example, the design value D of the diameter of the resin layer was 50 mm, and the design value t of the thickness was 200 μm. This satisfies the condition (formula (5)) described in the second embodiment.
Actually, when the diameter of the resin layer of each manufactured product was measured, there was almost no defective product (that is, the diameter error ΔD magnitude | ΔD | larger than the allowable error amount ΔDmax).
[0063]
For comparison, when the design value D of the diameter of the resin layer was 50 mm and the design value t of the thickness was 100 μm (the expression (5) was not satisfied), it was defective at a rate of 50%.
[Third embodiment]
As in the first and second embodiments, a plurality of diffractive optical elements having a resin layer made of optical resin on a glass substrate made of optical glass and having a phase-type diffractive surface at the boundary surface between them are prepared. did.
[0064]
As a material for the resin layer, an acrylic resin having a curing shrinkage rate α = 6% was used. Further, the outer diameter A of the glass substrate was 52.3 mm, and thus the maximum allowable amount Dmax of the diameter of the uncured product was 52.3-1.6 = 50.7 mm.
In this example, the design value D of the diameter of the resin layer was 50 mm, and the design value t of the thickness was 200 μm. This satisfies the condition (formula (13)) described in the third embodiment.
[0065]
In fact, when the end face of the resin layer of each manufactured product was measured, it was found that there were no defective products and all were well formed.
For comparison, when the design value D of the diameter of the resin layer was 50 mm and the design value t of the thickness was 100 μm (Formula (13) was not satisfied), the end face was defective at a rate of 50%.
[0066]
【The invention's effect】
  As mentioned above, according to this invention, the manufacturing method of the composite type optical element which can raise the yield, without adding a change to the formation method of the composite type optical element which has the resin layerButIt was realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a composite optical element 1 according to a first embodiment.
FIG. 2 is a diagram showing experimental results obtained by examining the presence or absence of bubbles and the change in the amount of undulation when the design value t of the thickness of the resin layer 11 is changed.
FIG. 3 is a cross-sectional view of a composite optical element 1 according to a second embodiment.
FIG. 4 is a diagram showing a state when a resin layer 11 is formed (when an uncured product 11 ′ is cured).
FIG. 5 is a cross-sectional view of a composite optical element 1 according to a third embodiment.
FIG. 6 is a diagram showing a state when the resin layer 11 is formed (immediately before the uncured material 11 ′ is cured).
FIG. 7 is a diagram illustrating a procedure for forming a resin layer 11 of a composite optical element.
[Explanation of symbols]
1 Compound optical element
10 Glass substrate
10a Diffraction surface
11 Resin layer
11 'uncured material
11a The surface of the resin layer 11
11a 'Surface of the uncured material 11'
12 Jig
Type 13

Claims (2)

On the first optical layer made of an optical material, an uncured product of resin, which is a material of the second optical layer made of resin, is set according to the thickness of the second optical layer and the design value of the formation range. A mold application step of supplying and applying a mold, and maintaining a distance between the mold and the first optical layer at a design value t of the thickness of the second optical layer;
A curing step of curing the uncured material in a state where the mold is applied and fixing the second optical layer on the first optical layer, comprising:
The design value t of the thickness of the second optical layer includes the design value D of the diameter of the second optical layer, the maximum error amount Δdmax of the positioning of the gap, and the maximum of the diameter of the second optical layer. For the allowable error amount ΔDmax,
ΔDmax ≧ | Dt ^0.5 ((t ± Δdmax) ^−0.5 −t ^−0.5 ) | is determined so as to satisfy the formula. On the first optical layer made of the optical material, an uncured product of the resin that is the material of the second optical layer made of resin, the design value of the thickness and formation range of the second optical layer, and the resin A mold application step for supplying the mold in accordance with a curing shrinkage rate, and maintaining a distance between the mold and the first optical layer at a design value t of the thickness of the second optical layer;
A curing step of curing the uncured material in a state where the mold is applied and fixing the second optical layer on the first optical layer, comprising:
The design value t of the thickness of the second optical layer is the maximum allowable amount Dmax of the diameter of the uncured product, the maximum error amount Δdmax of positioning of the interval, and the design value of the diameter of the second optical layer. For D and the curing shrinkage rate α (%) of the resin,
^{Dmax ≧ (D + (Dt 0.5} ((t-Δdmax) -0.5 -t -0.5)) / (( compound optical, characterized in that it is determined to satisfy the equation of 1-0.01α) ^1/3) Device manufacturing method.

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