JP3515801B2 - Materials for optical devices, optical devices, and optical device manufacturing methods - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to a material for optical devices.
-Regarding an optical device manufacturing method .

[0002]

2. Description of the Related Art As a novel optical device manufacturing method,
“A photoresist film having a substantially smooth upper end surface formed on the surface of an optical material is patterned by a photolithography method to form a cylindrical or elliptic cylinder photoresist film, and the photoresist film is heat-treated. Then, the substantially flat upper end surface of the photoresist film is deformed into a convex arc surface, and the surface of the optical material and the deformed photoresist film are etched, so that at least 1 similar to the convex arc surface of the photoresist film is etched. A method of "forming two convex arc surfaces on the surface of an optical material" has been proposed (Japanese Patent Laid-Open No. Hei 5-
173003 gazette claim 16).

The lens action of the microlens or microlens array manufactured by such a method is determined by the type and shape of the optical material and the refractive power of the convex arc surface formed on the surface of the optical material. It is difficult to realize a wide range of lens functions.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and intends to realize a novel optical device that easily realizes a wide range of lens functions .

That is, the object of the present invention is to provide the above-mentioned novel optical system.
It is to provide a method for manufacturing a device (claims 3 and 4).

Another object of the present invention is to provide an optical device material used for carrying out the above-mentioned optical device manufacturing method ( claims 1 and 2 ).

[0007]

According to a first aspect of the present invention, in a "material for an optical device", a layer of a transparent material having a refractive index different from that of the substrate is desired as a lens surface forming layer on at least one surface of the transparent substrate. Formed to a thickness of . Since the lens forming surface is formed on one or more surfaces of the substrate, it goes without saying that the lens surface forming layer may be formed on two or more surfaces depending on the shape of the substrate. As a method of forming the “lens surface forming layer” on the substrate, a known layer forming method such as vapor deposition, sputtering, CVD or the like can be appropriately used.

On the lens surface forming layer, a layer is further formed.
A layer of photoresist can be formed to the desired thickness
However, the material for an optical device according to claim 1 is the lens.
A plastic material layer having a desired thickness and an intermediate layer are provided on the surface forming layer.
And a thin layer of photoresist from the lens surface forming layer side.
And the above are laminated in the above order.

The plastic material forming the "plastic material layer" in the optical device material according to claim 1 is a thermoplastic material capable of forming a convex curved surface by heat flow and surface tension by heating, or an isotropic material. It is possible to use various plastic materials capable of forming a convex curved surface on the surface by pressure or the action of pressure and heat, and various resists can be preferably used.
Specific examples of the "plastic material" include polyvinyl chloride, polystyrene, polyurethane, and metal relates such as polyglycidyl methacrylate resin.

The "intermediate layer" may be formed as a thin film layer of a metal such as Cu or Al, or may be formed as a thin film layer of a non-metal material such as Si. When forming the intermediate layer as a metal thin film layer, the thickness: 2000 to 10000Å
Is preferable, and when the intermediate layer is formed as a thin film layer made of a non-metallic material, a thickness of 2000 to 5000Å is preferable. The intermediate layer can be formed by various vapor deposition or sputtering. The thickness of the “thin photoresist layer” formed on the intermediate layer is 3 μm or less, preferably 1 μm or less.

In the material for an optical device according to the above-mentioned claim 1 , light is shielded between the transparent substrate and one or more lens surface forming layers according to the lens surface to be formed in the lens surface forming layer or the arrangement thereof. Layers can be formed ( claims
Item 2 ). The "light-shielding layer" has, of course, an "opening" that allows light that has undergone a lens action by these lens surfaces to pass, depending on the lens surface or the arrangement of lens surfaces.

[0012] As a reference example, "method for manufacturing optical device"
Method ”is performed by using the material for an optical device according to claim 2.
Applied, patterning process, heat treatment process, etch
And a step of The "patterning step" is a step of patterning a lens pattern or a lens array pattern by photolithography on a photoresist layer of the optical device material formed directly on the lens surface forming layer or via a light shielding layer. "Heat treatment process"
Is a step of heat-treating the patterned photoresist layer to form a convex curved surface on the photoresist surface by heat flow and surface tension of the photoresist.

In the "etching process", dry etching is performed on the photoresist and the lens surface forming layer whose surfaces are convexly curved by the heat treatment process, and the convex curved surface shape of the photoresist is engraved on the lens surface forming layer. This is a step of obtaining a lens surface or a lens surface array corresponding to the lens pattern or the lens array pattern in the lens surface forming layer.

The "optical device manufacturing method" according to claim 3
Is carried out by using the optical device material according to claim 1 or 2 , and a patterning step, an intermediate layer etching step, a relief pattern forming step, and a convex curved surface forming step,
Etching process.

The "patterning step" is a step of patterning a lens pattern or a lens array pattern on a thin layer of photoresist by photolithography. The “intermediate layer etching step” is a step of etching the intermediate layer using the patterned thin layer of photoresist as a mask to transfer the photoresist pattern onto the intermediate layer. It is patterned into the same pattern as the resist pattern.
The intermediate layer etching step is performed by "wet etching" when the intermediate layer is formed as a metal thin film layer, but may be performed by wet etching when the intermediate layer is formed as a thin film of Si or the like. However, dry etching may be performed using CCl ₄ , CF _4, or the like.

The "relief-like pattern forming step" is a step of dry-etching the plastic material layer using the etched intermediate layer as a mask to obtain a relief-like pattern of the plastic material layer according to the lens pattern or the lens array pattern. is there. The dry etching performed at this time is of course “anisotropic etching”, and the plastic material layer is etched in the direction orthogonal to the surface, so that the lens pattern or lens array pattern formed in the thin layer of the photoresist is initially formed. , The shape is three-dimensionalized into a "relief pattern".

The "convex curved surface forming step" is a step of applying heat and / or pressure to the formed relief pattern to form the surface of the plastic material into a convex curved surface. When "pressure" is applied in the convex curve forming step, the pressure is of course "isotropic", and the pressure range is 6 to 10.
Atmospheric pressure is preferred.

In the "etching step", the plastic material layer and the lens surface forming layer whose surfaces are convexly curved are dry-etched to engrave the convex curved surface shape of the plastic material layer on the lens surface forming layer. This is a step of obtaining a lens surface or a lens surface array corresponding to the lens pattern or the lens array pattern on the lens surface forming layer, and dry etching is of course “anisotropic etching”.

The method of the reference example is excellent in the simplicity of the structure of the material for the optical device and the simplicity of the process, but the thickness of the photoresist layer formed on the lens surface forming layer is 50.
It is preferably not more than μm, more preferably not more than 35 μm. Since the radius of curvature of the convex shape formed as the surface shape of the photoresist by the heat treatment becomes smaller as the photoresist layer becomes thicker, this method is used in the case of forming a “relatively large radius of curvature” lens surface or lens surface array. Are suitable.

According to the third aspect of the present invention , the convex surface having a relatively small radius of curvature can be formed as the surface shape of the plastic material by increasing the thickness of the plastic material layer. Suitable for forming a lens surface array. In this case, the radius of curvature of the lens surface to be engraved on the lens forming surface itself is set by making the shape of the convex curved surface of the plastic material surface a shape with a relatively small radius of curvature and forming a small selection ratio in the subsequent etching process. Can be greater than the radius of curvature of the plastic material surface.

In the optical device manufacturing method according to the third aspect, the "selection ratio" in the etching step can be changed continuously or stepwise , whereby the shape of the lens surface formed in the lens surface forming layer. "Aspherical"
( Claim 4 )

The "exposure" in the patterning step by photolithography in the method of claim 3 may be performed by uniform exposure using a mask or may be performed by a method such as laser drawing. In addition, “ECR etching” is suitable as etching for performing the etching process. In addition, the shape of the pattern for each lens in the lens pattern or lens array pattern that is patterned in the patterning process for the photoresist layer or thin layer is a polygonal shape such as a circular shape, an elliptical shape, a quadrilateral shape, or a hexagonal shape. , Or slit-like.

In order to "change the selection ratio" in the method of claim 4 , the kind of introduced gas, the introduced amount of introduced gas,
One or more of high frequency and / or microwave power for plasma generation, device material temperature, and pressure may be controlled.

The optical device according to claim 3 or 4
The optical device can be manufactured by the manufacturing method. Various specific forms of the optical device are possible, for example, "a transparent substrate is a parallel plate, and a lens surface or a lens surface array is formed on a lens surface forming layer formed on only one surface of the parallel base. Have been configured " .
Such an optical device can be used as, for example, a microlens or a microlens array.

Alternatively, "a lens surface or a lens surface array is formed on a lens surface forming layer formed only on one surface of a substrate which is a transparent parallel plate, and the lens surface forming layer is formed on the other surface. in response to lenses plane or the lens plane array, it can also be in other lens surface or the lens plane array is formed "as news parallel plate is" transparent substrate, the surface of one side A lens surface or a lens surface array is formed on the formed first lens surface forming layer, and a second lens surface forming layer formed on the other surface corresponds to the lens surface or the lens surface array, Other lens surfaces or lens surface arrays are also formed " .

Such an optical device can be used as a biconvex microlens or a microlens array.

The transparent substrate may have various shapes other than the parallel flat plate, and may have, for example, a prism shape. As in the optical device according to claim 12, "the surface of the transparent substrate is a curved surface itself. Therefore, it has a larger radius of curvature than the radius of curvature of the lens surface or the lens surface in the lens surface array formed on the lens surface forming layer ”. That is, the transparent substrate itself may be the lens.

In addition, the above "transparent substrate is a parallel plate,
The lens surface forming layer formed on only one surface of the
Surface or lens surface array is formed "
1 pair of optical devices, by aligning the respective lens surfaces comrades or lens surface arranged each other, and the optical device of the configuration joined at a flat surface of another is also possible, that
In this case , "optical thin film" should be attached to the bonding surface of a pair of optical devices.
You may intervene .

The array arrangement in the microlens array may be a one-dimensional arrangement or a two-dimensional arrangement. Further, the shape of the microlens is not limited to a circular shape, but may be an elliptical shape, a polygonal shape, a cylinder shape, or the like.

[0030]

As described above, in the present invention, one optical device is composed of a combination of at least two materials having different refractive indexes. Therefore, a "combination of refractive indices" can be selected according to the optical characteristics, and a wide range of optical characteristics can be realized by selecting the shape of the lens surface together therewith.

FIG . 1 shows an optical device manufacturing method of a reference example.
It is a figure for explaining. In FIG. 1A, reference numeral 1 indicates a transparent substrate, and a lens surface forming layer 10 having a refractive index different from that of the substrate 1 is formed on the surface of the transparent substrate 1. The lens forming layer 10 is formed to have a desired thickness by vapor deposition, sputtering, CVD, or the like. The structure in which the lens forming layer 10 is formed on the substrate 1 is the basic structure of the optical device material according to claim 1.

A photoresist layer 12 is formed on the surface of the lens surface forming layer 10.

The photoresist forming the layers of the photoresist 12 is "positive type". FIG. 1A shows a “patterning step”. On one surface of the transparent glass substrate 30, a metal thin film 31 is formed so that the side of the metal film 31 of the mask 3 formed corresponding to the lens array pattern is brought into close contact with the surface of the layer of the photoresist 12. The layer of photoresist 12 is exposed by uniform irradiation of light through.

After exposure, the state where the photoresist 12 irradiated with light is removed by development is the state shown in FIG. 1B, and the "lens array pattern" is the photoresist 12.
Is patterned. Then, the patterned layer of the photoresist 12 is heated to a temperature equal to or higher than the glass transition point of the photoresist 12 to perform a "heat treatment step".
The surface of the photoresist has a convex curved surface (FIG. 1C).

Photoresist 12 having a convex curved surface
And the lens surface forming layer 10 have a selection ratio of 1:
When the “etching step” by anisotropic dry etching is performed, the convex curved surface shape of the photoresist 12 becomes
It is engraved “as it is” on the lens surface forming layer 10, and as shown in FIG. 1D, the lens surface array corresponding to the lens array pattern is obtained as the surface shape of the lens surface forming layer 10.

Since the radius of curvature of the convex curved surface formed on the photoresist 12 mainly depends on the thickness of the layer of the photoresist 12, depending on the radius of curvature of each lens surface in the lens array pattern to be formed, The layer thickness of the photoresist 12 is set. Then, the lens surface forming layer 1
The thickness of 0 is set so that a convex curved surface formed as the surface shape of the photoresist 12 can be formed.

When the selection ratio in the etching process is set to be larger (smaller) than 1, the radius of curvature of the convex curved surface engraved on the lens surface forming layer 10 is larger than the radius of curvature of the convex curved surface which is the surface shape of the photoresist 12. Small (large)
Become.

[0038]

FIG . 2 shows an embodiment of the optical device manufacturing method according to claim 3 . 2A, the lens surface forming layer 10, the plastic material layer 120 having a desired thickness, the intermediate layer 14, and the thin layer of the photoresist 16 are laminated on the transparent substrate 1 in the above order. 2 shows a material for an optical device that is configured as follows. This configuration is an example of the configuration of an optical device material of claim 1, wherein.

FIG. 2B shows a state in which the lens array pattern is patterned on the thin layer of the photoresist 16 by the "patterning step" by photolithography as in the example of FIG.

When the "intermediate layer etching step" of etching the intermediate layer 14 using the thin layer of the patterned photoresist 16 as a mask, the patterned pattern of the photoresist 16 is "as it is". It is shown in the middle layer 14. This state is shown in Figure 2.
It shows in (c).

When the "relief pattern forming step" for anisotropically dry-etching the plastic material layer 120 is performed using the etched intermediate layer 14 as a mask, the "relief pattern of the plastic material layer 120 according to the lens array pattern is formed. Pattern "is obtained. This state is shown in Fig. 2 (d).
Shown in. At this stage, the intermediate layer 14 and the thin layer of photoresist 16 used as a mask are removed.

Subsequently, a "convex curved surface forming step" is performed in which the surface of the plastic material is formed into a convex curved surface by applying heat and / or pressure to the formed relief pattern. In this example, the plastic material layer 12 is a thermoplastic material layer, and in the convex curved surface forming step, the relief pattern of the plastic material layer 120 is heated to make the surface convex curved surface by the action of heat flow and surface tension. ing. FIG. 2F shows a state after the convex curved surface forming step.

The plastic material layer 120 having a convex curved surface
The lens surface forming layer 10 is dry-etched, and the convex curved surface shape of the plastic material layer surface is engraved on the lens surface forming layer to form a lens surface array corresponding to the lens array pattern on the lens surface forming layer 10. The obtained "etching step" is the same as the etching step of the optical device manufacturing method according to claim 5 described with reference to FIG. Figure 2
(G) shows the state after the etching step.

When a parallel plate is used as the transparent substrate 1 in the embodiment described with reference to FIGS.
A microphone in which a lens surface array is formed by a lens surface forming layer 10 on one surface of a transparent parallel plate 1 as shown in FIG.
A lens array can be obtained . In this microlens array, since the refractive index of the lens surface forming layer 10 forming the refracting surface portion of each microlens and the refractive index of the parallel plate that is the transparent substrate 1 are different, various optical characteristics are possible.

For example, if the refractive index of the transparent substrate 1 is higher (lower) than that of the lens surface forming layer 10, the focal length is longer than in the case where the entire surface is made of the same material as the lens surface forming layer 10. Can be (shortened).

FIG. 3B shows the surface shape of the transparent substrate 1 itself on the surface opposite to the surface on which the lens surface array is formed by the parallel flat plate lens surface forming layer 10 which is the transparent substrate 1. This is an example in which a lens surface array is formed . Of course, the individual lens surfaces in the lens surface array formed as the surface shape of the transparent substrate 1 itself are in optical axis alignment with the individual lens surfaces in the lens surface array formed by the lens surface forming layer 10. This optical device can be used as a microlens array with biconvex microlenses.

To form a lens surface or a lens surface array based on a convex curved surface as the surface shape of the transparent substrate 1 itself,
On the surface of the transparent substrate 1 itself, on the photoresist layer, a lens array pattern is patterned by photolithography, the patterned photoresist layer is heat-treated, and the photoresist surface is subjected to heat flow and surface tension of the photoresist. After forming the convex curved surface, the photoresist and the lens surface forming layer may be dry-etched to engrave the convex curved surface shape of the photoresist on the transparent substrate.

Alternatively, a plastic material layer, an intermediate layer and a thin layer of photoresist are laminated on the surface of the transparent substrate 1 itself,
The lens array pattern is patterned by photolithography on a thin layer of photoresist, the intermediate layer is etched using the patterned thin layer of photoresist as a mask, the photoresist pattern is transferred to the intermediate layer, and then etched. Using the formed intermediate layer as a mask,
The plastic material layer is dry-etched to obtain a relief pattern of the plastic material layer according to the lens array pattern, and heat and / or heat is applied to the formed relief pattern.
Alternatively, the surface of the plastic material is made to have a convex curved surface by applying pressure, and the plastic material layer and the lens surface forming layer having the convex curved surface are dry-etched to make the convex curved surface shape of the plastic material layer the lens surface. It may be performed by carving on the forming layer.

In FIG. 3C, another lens surface forming layer 10A forms a lens on the surface opposite to the surface on which the lens surface arrangement is formed by the parallel flat plate lens surface forming layer 10 which is the transparent substrate 1. This is an example in which a plane arrangement is formed . The formation of the lens surface array by the lens surface forming layer 10A is performed as shown in FIG.
It may be performed by the method described and described in.

The lens surface arrangements on both surfaces of the transparent substrate 1 correspond to each other, so that this optical device can be used as a microlens array with biconvex microlenses. A light-shielding layer 11A is formed on the surface on which the lens surface array is formed by the lens surface forming layer 10. The light-shielding layer 11A can be formed by a metal film or printing. When the wavelength used is special, for example, a photoresist is used, and an opening is formed by photolithography.
The light shielding layer can be formed using the photoresist itself. The light-shielding layer can be formed on the surface on which the lens surface array is formed by the lens surface forming layer 10A, as shown in FIG.
Also for the embodiments shown in (a) and (b), it can be formed on one or both surfaces.

In the embodiment of FIG. 3C, the maximum number of individual microlenses in the microlens array is four.
It is possible to combine different types of refractive index, and it is possible to design an optical device for a very wide range of optical purposes.

FIG. 4A shows an example of an optical device material according to claim 4. The transparent substrate 1 is a parallel plate, and a lens surface forming layer 10 is formed on the surface of the transparent substrate 1 with a light shielding layer 11 interposed therebetween. The light shielding layer 11 is formed according to the lens surface to be formed in the lens surface forming layer or the arrangement thereof .

When a lens surface array is formed on the lens surface forming layer 10 of such an optical device material by the method described with reference to FIG. 1 or 2, as shown in FIG. 4 (b). It is possible to obtain a microlens array having a light blocking layer in the form of a "pupil diaphragm" inside the lens.

The light-shielding layer optically separates the individual microlenses in the microlens array and prevents light that should enter the adjacent microlenses from entering as stray light, so that the optical function of the microlens array is improved. Be beneficial to.

In the example of FIG. 4 (b) as well, FIG. 3 (b),
Similar to the example (c), the it goes without saying that can form a lens surface arranged on both surfaces of the transparent substrate 1.

In the embodiment shown in FIGS. 3 (b), 3 (c) and 4 (b), lens surface arrays are formed on both sides of the transparent base 1 which is a parallel plate. In this case, it is needless to say that the lens surface arrays formed on both sides of the base body 1 need to be aligned with each other with high accuracy, and the lens performance of each lens formed on each surface is desired optical performance. Must have performance.

The probability of misalignment of the lens surface arrangements on both surfaces of the substrate 1 and the probability that the lens performance of the lenses formed on the respective surfaces will not satisfy the desired performance cannot be set to 0 in practice. Therefore, when manufacturing an optical device having a lens surface array on both sides, the probability that a product that does not conform to the standard will be manufactured is the product of each of the above probabilities. b), (c) and FIG.
The yield of manufacturing an optical device as shown in (b) is
The improvement is not always easy.

In this case, two pieces of a transparent plate which is a parallel plate having a desired lens surface arrangement formed on one surface are separately manufactured, and these two optical devices are bonded to each other by a smooth surface of the parallel plate. Then, if they are integrated, good optical devices can be used as the optical devices to be combined, and the alignment is easy. It is possible to effectively improve the manufacturing yield of an optical device in which lens surface arrays are formed on both surfaces.

FIG. 5 shows three examples of such a case . FIG. 5A shows an optical device in which a lens surface array is formed by a lens surface forming layer 10 on one surface of a transparent substrate 1 which is a parallel plate, and a transparent substrate 1 ′ which is a parallel plate.
This is an example in which an optical device having a lens surface array formed by the lens surface forming layer 10 'is joined to one surface of the above with the smooth surface of the bases 1 and 1' .

FIG. 5B is the same as FIG. 3B by joining an optical device 5A of the type shown in FIG. 3A and a lens surface array 5B having a lens surface array formed on one surface. 5C is an example of an optical device having the function of FIG.
This is an example similar to (a), in which the "optical thin film" 1a is formed on the joint surface of the substrates 1, 1 ' . When a desired spectral transmittance is given to the optical thin film 1a, a lens action and a wavelength selecting action can be given as the functions of the optical device.

In each of the embodiments shown in FIG. 5,
3 (c) is provided on one or more of the surfaces on which each lens surface array is formed.
It is possible to form the same light-shielding film as in the above, and to combine one or both of the optical devices,
As shown in FIG. 4B, the light shielding layer 11 may be provided.

The bonding method may be a method using an adhesive, but known "anodic bonding" and "high temperature bonding" are preferable. "Anodic bonding" means first and second substrates 1, 1'to be joined.
Is a glass plate, and the difference in the alkali content of each glass plate is used. That is, when a “relatively low alkali” glass plate is used as the substrate 1 and a “relatively high alkali” glass plate is used as the substrate 1 ′, the second substrate 1 ′ becomes the first substrate 1. On the other hand, it means that the amount of “alkali ion” such as + ion of Na is relatively high.

Therefore, in the state where the first and second bases 1 and 1'are in contact with each other on their smooth surfaces, a strong electric field is applied from the side of the second base 1'to the side of the first base 1. While heating the first and second bases 1 and 1 ′ to a high temperature of about 400 ° C., the second energy is increased by the action of thermal energy and electric field.
“Alkali ions” move from the substrate 1 ′ to the first substrate 1 and the transferred ions are fixedly received in the first transparent substrate.

When the "migration of alkali ions" occurs in this way, at the interface between the first and second substrates 1 and 1 ',
The first substrate 1 is in a state of "ion rich" compared to the normal state, and the second substrate 1'is "ion deficient" in comparison with the normal state.
Occurs. Therefore, the first substrate 1 has a positive charge due to the received alkali ions inside the substrate, and the second substrate 1'has a "negative charge due to alkali ion deficiency" inside the substrate. Second base 1,1 '
Is extremely strongly chemically bonded under the action of a strong "electrostatic attraction" by the space charge layer.

"High temperature bonding" is a bonding method utilizing optical contact and chemical reaction. Clean glass surfaces are extremely active, and bringing these clean mirror-like glass surfaces into contact gives strong adhesion at room temperature. This phenomenon is called optical contact. The heat treatment increases the adhesive strength of the optical contact. The effect of this heat treatment is explained by the following chemical reaction.

That is, as the first and second substrates 1, 1 ',
When a glass containing SiO ₂ such as glass is used and these mutually smooth surfaces are heated with “monomolecular layer” of H ₂ O interposed, the oxygen bonding layer on the surface of the substrate softens at high temperature. Since it becomes a molten state, the H ₂ O in the monomolecular layer becomes “H” and “O”.
-H "is polarized and" H "is combined with" -Si-O- "to generate" Si-OH ". At this time, "-Si-O
-Si- "causes a dangling bond.

Next, "O-H" is bonded to "Si-O-H", H ₂ O is removed by a dehydration reaction, and "Si-O-S" is removed.
i "can be combined. Furthermore, "Si-OH" and "HO-
Similarly, H ₂ O is removed from Si by a dehydration reaction,
-O-Si bond can be formed. That is, through the "O], first, the Si comrades second substrate 1,1 'binding. H ₂ O produced in the dehydration reaction at this time is dissipated from the junction by diffusion interface. The In this way, the first and second substrates 1, 1'are joined.

When bonding is performed as in these examples, a maximum of four types of refractive index can be combined as the refractive index of each substrate and the lens surface forming layer, so that a wider range of optical characteristics can be accommodated. Enables the design of optical devices.

Although FIGS. 3 to 5 show examples of the microlens array, the "microlens" or "lens" can be realized by setting the number of lens surfaces formed on the substrate to one. A microlens or lens can be realized by dividing such a microlens array or lens array for each microlens.

Although FIGS. 3 to 5 show examples in which the "parallel plate" is used as the transparent substrate, the shape of the substrate is not limited to the parallel plate. For example, as shown in FIG. 6A, an optical device in which a lens surface or a lens surface array is formed by a lens surface forming layer 10C formed on one or more surfaces of a transparent base 1A on a prism is possible. As shown in FIG. 6B, an optical device in which a minute lens array is formed by the lens surface forming layer 10D on the lens surface of the lens 1B as a transparent substrate is also possible .

When the embodiment of the optical device manufacturing method according to claim 6 is described with reference to FIG. 2, the plastic material layer 120 is subjected to the “convex curved surface forming step” for the relief pattern formed by the plastic material layer. The relief pattern of No. 1 was heated and the surface was made into a convex curved surface by the action of heat flow and surface tension. However, the convex curved surface can also be made by pressure, in which case a thermoplastic material is always used. There is no need.

In FIG. 7A, reference numeral 2 indicates a plastic material layer formed on the lens surface forming layer 10 and formed in a relief pattern. In this state, when a pressure of about 6 to 10 atm is isotropically applied to the plastic material layer 2, the plastic material layer 2 is deformed by the pressure, but the deformation occurs so that the pressure is received in the minimum area. Therefore, as shown in FIG. 7B, it is curved into a spherical shape.
Therefore, when the curved surface shape is engraved on the lens surface forming layer 10 by the etching process, as shown in FIG.
A desired lens surface can be obtained on the lens surface forming layer 10.

If the plastic material layer is made of a thermoplastic material and is heated while pressure is applied, convex curved surfaces can be easily realized in an extremely short time.

Although not particularly mentioned, in the embodiment described above, the lens shape patterned in the patterning step is "circular". If this pattern is, for example, a "slit shape", a "cylinder lens" can be formed.

The lens surface to be formed is not limited to a spherical surface or a cylinder surface, but various aspherical surfaces are possible. The case of forming an aspherical surface will be described below.

There are basically two possible methods for forming an aspherical lens surface. That is, the first method is a method in which the convex shape formed on the photoresist layer or the plastic material layer is a spherical shape, and the surface shape is aspherical in the step of engraving the surface shape on the lens surface forming layer. The second method is a method in which an aspherical surface is formed in the step of making the photoresist layer or the plastic material layer into a convex curved surface, and this is engraved on the lens surface forming layer. Various methods are possible.

First, an example of the first method will be described.

FIG. 8A shows a plastic material layer formed in a “relief pattern” on the lens surface forming layer 10. When the “convex curved surface forming step” is performed on this state, a state in which the surface of the plastic material 2 is formed into a convex curved surface 2A is realized as shown in FIG. 8B. FIG. 8C shows
In contrast to the state of (b), a state in which an anisotropic etching process is performed halfway is shown. In this state, the plastic material 2 is still
Some of the remains.

From this state, if the dry etching selection ratio in the etching step is set to be smaller than 1, for example, 1/2, the etching rate of the lens surface forming layer is 1:
Since the etching rate of the plastic material layer 2 becomes 2, in the state where the plastic material layer 2 is completely etched, FIG.
As shown in (d), an aspherical lens surface with a flattened top can be formed in the lens surface forming layer 10.

On the contrary, from the state of FIG. 7C, the selection ratio: 1 /
When the etching process is performed halfway in step 2, the top has a protruding shape as shown in FIG. 6 (e). From this state, etching is performed at a selection ratio of 1 to etch the plastic material layer 2. When you make a horsetail, as shown in Fig. 8 (f),
The lens surface forming layer 10 can be formed with an aspherical lens surface having a gentle skirt and a protruding top.

[0081] The above claim in an optical device manufacturing method according to claim 3, wherein, for a selected ratio in the etching process by continuously or stepwise changing, characterized in that the shape of the lens surface aspherical 4 is an example of the method for manufacturing an optical device described in 4 .

In FIG. 9, the plastic material layer 2 formed as a relief pattern on the lens surface forming layer 10 is a "negative photoresist layer or an ultraviolet curable resin material layer". , (A), when irradiated with ultraviolet light whose intensity is high in the central part, the polymer in the plastic material is bound by radicals in the irradiated part, so that it is proportional to the intensity of the irradiated ultraviolet light. Therefore, the fluidity becomes worse as the portion is irradiated with strong ultraviolet rays. When the “convex curved surface forming step” is performed by the action of pressure in such a state, FIG.
As shown in (b), the part with poor fluidity is “pushed up” due to the deformation in the part with good fluidity, and as shown in the figure, the convex curved surface shape is bulged so that the central part projects. Is obtained.

Therefore, if the etching process is performed in this state, and if the plastic material 2 and the lens surface forming layer 10 have the same etching rate, as shown in (b) of FIG. When a convex curved surface shape that is substantially congruent with the convex curved surface shape is engraved on the lens surface forming layer and the etching rate of the lens surface forming layer 10 is higher than that of the plastic material 2, the engraved shape is as shown in FIG. It becomes like the shape 1-20 of (c), and in the opposite case, it becomes like the shape 1-30.

In FIG. 10A, the lens surface forming layer 1
On the device material 1, a relief pattern of the plastic material 2 made of a positive photoresist is formed.
When the plastic material 2 is irradiated with ultraviolet rays or the like as light in the range shown in FIG. 10A, for example, the polymer inside the photoresist, which is the plastic material, is cut at the light-irradiated portion, and the fluidity becomes large. Become. When the “convex curved surface forming step” is executed by the action of pressure in such a state, the easiness of deformation in the part of the plastic material pattern 20 changes. It is possible to realize a convex curved surface shape of "recessed mountain shape".

When the "convex curved surface shape" as shown in FIG. 10 (b) is formed, the etching process is performed. When the plastic material layer 2 and the lens surface forming layer 10 have the same etching rate, the lens surface forming is performed. The convex curved surface shape engraved in the layer 10 is substantially congruent with the convex curved surface shape of the plastic material 2 itself as shown by the shape 1-1 in FIG. 10C, and the etching rate of the lens surface forming layer 10 is plastic. If the material 2 is larger than that of the material 2, the engraved shape becomes the shape 1-2 of FIG. 10C, and in the opposite case, the shape 1-3.

In addition, for example, the etching process is initially performed as follows.
By performing the selection ratio at 1 and halving the selection ratio from the middle, it is possible to realize a lens surface shape with a flattened top as shown in FIG.

Specific examples will be given below. Specific Example 1 Quartz glass having a length of 5 mm, a width of 2 mm, a thickness of 0.5 mm, and a refractive index of 1.452 (for light having a wavelength of 1.3 μm) was used as a “transparent substrate”. On one surface of this quartz glass, SiO ₂ containing TiO ₂ was formed into a film with a thickness of 5.8 μm by a vacuum deposition method to form a “lens surface forming layer” having a refractive index of 1.502.

On the lens surface forming layer, "polyglycidyl methacrylate resin" as a plastic material layer, thickness:
It is formed to a thickness of 5.0 μm, and an intermediate layer of “Cu
Layer ”by vapor deposition to a thickness of 3000 Å, and then a photoresist (trade name: OFPR800) manufactured by Tokyo Ohka Kogyo Co., Ltd. is spin-coated on the layer, and prebaked to a thickness of 1.0 μm. Formed as a thin layer.

First, 10 "black circles" having a diameter of 0.2 mm are prepared.
Exposure is performed using a "mask" arranged in a row with a pitch of 0.25 mm, and the "light-irradiated portion" is removed to pattern the "lens arrangement pattern" with the arrangement pattern of the black circles. "Patterning process"
Then, the "intermediate layer etching step" was performed on the intermediate layer by wet etching using the thin layer of the patterned photoresist as a mask, and the photoresist pattern was transferred to the intermediate layer.

That is, distilled water; 100 ml of hydrochloric acid (1.1
9); 6 ml, and iron (III) chloride; 20 g were added and mixed, the temperature was maintained at 20 to 30 ° C., and wet etching was performed by spraying vertically from a nozzle onto the quartz glass surface for 1 to 2 minutes. At this time, the quartz glass was rotated, and the surface of the quartz glass was kept in the vertical direction so that there was no "liquid pool".
After etching, rinse with distilled water was performed.

Subsequently, the plastic material layer is dry-etched using the metal thin film layer which is the intermediate layer as a mask to obtain a relief-shaped pattern of the plastic material layer according to the above lens arrangement pattern. Was performed as follows.

That is, quartz glass was set in an ECR plasma etching apparatus, oxygen: 7 sccm, Ar: 1 sc
cm, introducing pressure in reaction chamber: 3 to ⁴ × 10 to ⁴ Tor
r, microwave effective power: 640 W, RF effective power: 4
Etching was performed at 70 W for 25 minutes.

Further, the metal thin film layer is removed, and the relief-shaped pattern of the plastic material layer formed in the "relief-shaped pattern forming step" is subjected to a "convex curved surface forming step" at a heating temperature of 200 ° C. The heating time was 30 minutes. The “height from the lens surface forming layer surface to the top” of the 10 convex curved surface shapes formed by the convex curved surface forming step is 5.75 μm.
Then, the “curvature radius” was 0.872 ± 0.006 mm.

Subsequently, an "etching step" for engraving the above-mentioned ten convex curved surface shapes on the lens surface forming layer was performed by ECR etching as follows. That is, quartz glass is set in an ECR plasma etching device, and oxygen is supplied;
2.5 sccm, Ar; 1 sccm, CHF ₃ ; 8 sc
introducing cm, reaction chamber pressure: 2~3 × 10 ~ ⁴ Tor
r, microwave effective power: 640 W, RF effective power: 4
Etching was performed at 80 W for 52 minutes.

The etching rate for the plastic material layer,
The etching rates for the lens surface forming layer are almost equal to each other, so that the convex curved surface shape formed on the lens surface forming layer was 0.876 ± 0.006 mm.

Thus, a "microlens array" of the type shown in FIG. 3 (a) was obtained. The lens surface of each microlens constituting the microlens array has a diameter of 0.2.
10 mm, such lens surfaces are arranged in the longitudinal direction of the quartz glass at a pitch of 0.25 mm. The focal length of each lens is 1.883 mm.

Concrete Example 2 Length: 4 mm, Width: 2 mm, Thickness: 0.5 mm, Refractive Index: 1.452 (for light of wavelength: 1.3 μm)
Quartz glass was used as a "transparent substrate". First, on one surface (first surface) of this quartz glass, an SF-60 glass material was formed into a film with a thickness of 7.1 μm by a sputtering method to form a “lens surface forming layer” having a refractive index of 1.768. .

On this lens surface forming layer, a layer of "polyglycidyl metal relate resin" was formed as a plastic material layer to a thickness of 6.1 μm, and an "intermediate layer" was formed thereon.
Thickness: 1500Å "Si layer" is formed by vapor deposition.
A photoresist (trade name: OFPR800) manufactured by Tokyo Ohka Kogyo Co., Ltd. was spin-coated thereon and prebaked to form a thin layer having a thickness of 1.5 μm.

Exposure is performed using a "mask" in which 10 black circles having a diameter of 100 μm are arranged in a row at a pitch of 250 μm, and the exposed parts are removed to remove the black circles. The "lens array pattern" corresponding to the array was left as a thin layer of photoresist (patterning step).

After the patterning step, the "optical device material" is set in an ECR plasma etching apparatus, and C
Cl ₄ : 15 sccm was introduced, and the reaction chamber pressure was 3 to 4
× 10 ~ ⁴ Torr, microwave power: 640W, R
F Execution power: 480W, dry etching 3
It is performed for a minute (intermediate layer etching step), and then, the "relief pattern forming step" is performed under the above-mentioned "same condition as the specific example 1".
Etching was performed by changing to _4, and a thin layer of Si (remaining film of the intermediate layer) was removed. Hereinafter, the “convex curved surface forming step” and the “etching step” were performed under the same conditions as in Example 1.

After the convex curved surface forming step, the diameter of the convex curved surface which is the surface shape of the plastic material is 100 μm, the height from the lens surface forming layer surface at the top of the convex curved surface is 7.0 μm, the surface of the lens surface forming layer after the etching step. The diameter of each lens surface in the lens surface array engraved on is 100 μm, and the array pitch is 2
It was 50 μm and the radius of curvature was 0.200 mm.

On the other hand, on the other surface (second surface) of the above-mentioned quartz glass which is a "transparent substrate", SF-60 glass material is formed by sputtering to a thickness of 17.6 μm,
The "lens surface forming layer" having a refractive index of 1.768 was used.

A plastic material layer (polyglycidyl metal relate resin layer) is formed on the lens surface forming layer, and the thickness is 14.8.
μm, and the “intermediate layer and photoresist layer” are
The same thing as the above "first surface" was formed.

As the "mask" used in the patterning step, ten black circles having a diameter of 240 μm arranged at a pitch of 250 μm were used. All the other conditions were the formation conditions for forming the lens surface arrangement on the “first surface” side. A lens surface array was formed in the same manner.

In the patterning process, the "lens surface arrangement" formed on the first surface and the accurate alignment with the mask (the lens surface arrangement to be formed on the second surface, It goes without saying that the formed lens surface array is aligned with the optical axes of the corresponding lens surfaces.

After the “convex curved surface forming step”, the diameter of the convex curved surface formed on the plastic material layer is 240 μm, the height of the top of the convex curved surface from the lens surface forming layer surface is 17.0 μm, and the lens surface forming layer is formed after the etching step. The diameter of each lens surface in the lens surface array engraved on 240 μm, the array pitch is 25
The radius of curvature was 0 μm and the radius of curvature was −460 μm. Finally, a light-shielding layer was formed on one surface (first surface) by metal thin film vapor deposition. In this way, a "microlens array" of the type shown in FIG. 3 (c) could be obtained. The microlens array of this specific example 2 is used as an optical element of a coupler for optical communication, and can collimate each divergent laser light flux from an LD array into a parallel light flux having a beam diameter of 240 μm. FIG. 11 shows a “collimating function” for a laser light flux from an LD by one microlens in the microlens array of the specific example 2.
Is illustrated. In the figure, R represents the radius of curvature of the lens surface, and n represents the refractive index. Also, the numerical value at the bottom of the figure represents "distance". The units of radius of curvature and distance are "m
m ”.

As the transparent substrate in the above specific example 1,
The one using "SiO ₂ glass" instead of the quartz glass and the one using "Si having a small ion radius, Li,
Monovalent positive ions such as Na and K, Pb, Mg and C
a, Cd, etc. containing a divalent positive ion-containing aluminosilicate-based or low-melting glass-based material, etc. " A lens array of the type shown in FIG. 5A can be realized by anodic bonding.

In the above description, the case where the lens surface or the lens surface array having the convex curved surface is formed in the lens surface forming layer has been described. However, the lens surface or the lens surface array having the concave curved surface is formed in the lens surface forming layer. Note that it is also possible.

For example, a mold having a convex curved surface corresponding to the lens surface shape of the concave curved surface to be formed is used, this mold is placed on the lens surface forming layer, and a photocurable resin is injected between the two, and the light is applied from the side of the substrate. Irradiation is performed to cure the resin. By doing so, the resin layer is formed on the lens surface forming layer, and a concave curved surface is formed on the surface thereof. Then, anisotropic dry etching may be performed to engrave the concave curved surface shape on the lens surface forming layer. By changing the etching selection ratio continuously or stepwise over time,
The shape of the concave curved surface to be carved can be variously modified.

[0110]

As described above, according to the present invention, the novel
An optical device material and an optical device manufacturing method can be provided.

The "optical device material" described in claims 1 and 2 can easily and surely carry out the optical device manufacturing method described in claims 3 and 4 . Claim
In the optical device manufacturing methods described in 3 and 4, as described above, since two or more regions having different refractive indexes can be included in a single optical device, the degree of freedom in designing the optical device is increased, and a wide range of optical devices can be obtained. It enables the manufacture of characteristic optical devices. Particularly, in the optical device manufacturing method according to the fourth aspect, an aspherical lens surface or lens surface arrangement is possible, and an optical device having a special optical function can be manufactured.

The optical device manufactured by the above method is manufactured by
The production yield is good, and the refractive power of the substrate surface itself
As the surface shape of the lens surface forming layer formed on the surface side of
Combine the refractive power of the lens surface or lens surface array
It can also be used in addition to the lens function, wavelength
It can also have a selection function.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a reference example method.

FIG. 2 is a diagram for explaining one embodiment of the invention according to claim 3 ;

FIG. 3 is a diagram showing three examples of optical devices .

[Figure 4]Claim 2Example of Material for Optical Device
(A) and formed using thisOptical device example
It is a figure which shows (b).

FIG. 5 is a diagram showing an example of an optical device .

FIG. 6 is a diagram showing an example of an optical device .

FIG. 7 is a diagram for explaining a case where the “convex curved surface forming step” of the optical device manufacturing method according to claim 3 is performed by the action of pressure.

FIG. 8 is a drawing for explaining one example of the optical device manufacturing method according to claim 4 ;

FIG. 9 is a diagram illustrating an example of forming an aspherical lens surface or a lens surface array in the lens surface forming layer in the optical device manufacturing method according to the third aspect of the present invention.

FIG. 10 is a diagram for explaining another example of forming an aspherical lens surface or a lens surface array in the lens surface forming layer in the optical device manufacturing method according to the third aspect of the present invention.

FIG. 11 is a diagram showing a collimating function of an arbitrary microlens in the microlens array of the embodiment described as the second specific example.

[Explanation of symbols]

1 transparent substrate 10 Lens surface forming layer 12 Photoresist layer

Continuation of front page (56) Reference JP-A-5-40216 (JP, A) JP-A-4-226073 (JP, A) JP-A-5-164904 (JP, A) JP-A-3-91960 (JP , A) JP 5-283663 (JP, A) JP 4-74471 (JP, A) JP 3-181934 (JP, A) JP 7-174903 (JP, A) JP 7-218702 (JP, A) JP 7-159604 (JP, A) JP 6-250002 (JP, A) JP 6-194502 (JP, A) JP 7-164549 (JP, A) JP-A-7-174902 (JP, A) JP-A-7-181303 (JP, A) JP-A-5-29590 (JP, A) JP-A-4-359472 (JP, A) JP-A-5 -173003 (JP, A) JP 5-67762 (JP, A) JP 6-252372 (JP, A) JP 6-334160 (JP, A) JP 57-8502 (JP, A) ) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 3/00

Claims (4)

(57) [Claims] 1. A layer of transparent material having a refractive index different from that of the substrate is formed on one or more surfaces of the transparent substrate to have a desired thickness as a lens surface forming layer, and a desired layer is formed on the lens surface forming layer. Thickness of plastic material layer
The intermediate layer and a thin layer of photoresist
A material for optical devices, which is formed by stacking layers in this order from the surface forming layer side . 2. The optical device material according to claim 1 , wherein a lens surface to be formed in the lens surface forming layer or an arrangement thereof is provided between a transparent substrate and one or more lens surface forming layers. A material for an optical device having a light-shielding layer formed thereon. 3. A patterning step of patterning a lens pattern or a lens array pattern by photolithography on a thin layer of photoresist of the material for an optical device according to claim 1 or 2 , and a thin layer of patterned photoresist. The intermediate layer is etched using the intermediate layer as a mask and the photoresist pattern is transferred to the intermediate layer, and the plastic material layer is dry-etched using the etched intermediate layer as a mask. A relief pattern forming step of obtaining a relief pattern of the plastic material layer according to the pattern, and a convex curved surface for making the surface of the plastic material into a convex curve by applying heat and / or pressure to the formed relief pattern And the process of making the surface convex By performing dry etching on the plastic material layer and the lens surface forming layer and engraving the convex curved surface shape of the plastic material layer on the lens surface forming layer, the lens surface forming layer corresponds to the above lens pattern or lens array pattern. And an etching step for obtaining a lens surface or an array of lens surfaces. 4. The optical device manufacturing method according to claim 3, wherein the shape of the lens surface is made aspheric by changing the selection ratio in the etching step continuously or stepwise. Method.