JPH06250002A - Microlens, microlens array and their production - Google Patents

Abstract

PURPOSE:To provide a microlens and a microlens array having high utilizing efficiency of light and to provide production method for these. CONSTITUTION:A film 3 of uniform thickness consisting of a thermally deforming photosensitive material is formed on a transparent substrate 1, and the film 3 is patterned with light according to lenses and arrangement of lenses in the microlens array to be produced. The patterned film 3 is irradiated with light and heated at a temp. higher than the thermal deformation temp. so that the array arrangement of the photosensitive material having smooth projections 3A is formed by thermal deformation and surface tension of the photosensitive material. Then, the surface having the array arrangement is subjected to dry etching to produce a relief of the array arrangement having projections 3A in the substrate. Thus, any forms of refractive plane and the array arrangement can be formed on the substrate 1 to obtain a microlens array 1A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens / microlens array and a manufacturing method thereof.

[0002]

2. Description of the Related Art A microlens array is a one-dimensional or two-dimensional array of minute microlenses (usually having a lens diameter of several hundred μm or less), which is widely known in microoptics related to the field of optoelectronics. Has been.

Various methods for manufacturing a microlens array have been proposed, but the most practical method among them is the so-called "thermal deformation method". The thermal deformation method is a method of forming a film of a thermally deformable photosensitive material on a substrate and performing optical patterning by a pattern according to the shape of the microlenses on which the film is to be formed and its arrangement state. Production of a microlens array by heating a patterned film of a photosensitive material to a heat deformation temperature to form a refracting surface by utilizing the heat deformability and surface tension of the photosensitive material and then solidifying the surface. Is the way.

However, in the microlens array manufactured by the thermal deformation method, since each lens is formed of a photosensitive material, "the lens material itself is light-absorbing", and the light utilization efficiency must be sufficiently high. Is difficult. In addition, since the lens material is thermally deformable, it cannot be used under high temperature conditions and has poor environmental resistance. There is also a problem that it cannot be used.

Further, when the microlens array is used, for example, as a focusing screen for focus detection of a lens shutter camera, in view of light utilization efficiency, individual microlenses are connected to each other to form an array, Although it is desirable that all the light incident on the entire array can be collected by the microlenses, it is difficult to form a microlens array in which the microlenses are connected to each other by the “conventional thermal deformation method”.

Further, the production of microlenses by the above-mentioned thermal deformation method has a problem that the production time is long and the production efficiency is poor.

Furthermore, according to the conventional thermal deformation method, the lens diameter:
In order to obtain a microlens of 100 μm or more, it is necessary to increase the thickness of the film of the photosensitive material formed on the substrate, which increases the curvature of the refracting surface formed by thermal deformability and surface tension. Since the focal length becomes shorter, it is difficult to increase the focal length of the microlens, and it is difficult to control local heating. Can not be changed.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a microlens and a microlens array having a high light utilization efficiency and a method for manufacturing the same. Another object of the present invention is to provide a microlens and a microlens array having a long focal length despite a large lens diameter, and a method for manufacturing the same. Another object of the present invention is to provide an extremely efficient method for manufacturing a microlens and a microlens array. Still another object of the present invention is to provide a novel microlens and microlens array that can be used even for high energy light under high temperature conditions, and a method for manufacturing the same.

[0009]

A manufacturing method according to a first aspect of the present invention includes a film forming step, a photo patterning step, a light irradiation step, a heating step, and an etching step. The "film forming step" is a step of forming a film having a uniform thickness of a heat-deformable photosensitive material on a transparent substrate. The term “transparent” of the substrate means that the substrate is transparent to light having a wavelength used for the microlens array, and does not necessarily have to be transparent to all wavelengths.

In the "photo-patterning step", a film having a uniform thickness made of the above-mentioned heat-deformable photosensitive material is photo-patterned according to a pattern corresponding to each lens and its arrangement in the microlens array to be formed. It is a process to do. "Photo-patterning" means exposing a photo-sensitive film according to the above pattern to remove unnecessary portions (exposed or unexposed portions) of the photosensitive material film formed on the substrate. Then, the shape is matched with the pattern. The “light irradiation step” is a step of performing light irradiation on the entire surface of the above-mentioned photo-patterned film. This light irradiation step is performed to cut the linear molecules in the film by light energy, and the type of light to be irradiated (wavelength range and intensity) is the extent to which the linear molecules are cut according to the material and morphology of the film. It is determined by

In the "heating step", the film irradiated with light is heated to a heat deformation temperature to form an array array of photosensitive materials having a smooth convex shape due to the heat deformability and surface tension of the photosensitive material. It is a process to do. In the "etching step", dry etching is performed on the surface on which the array array is formed,
It is a step of forming a desired refractive index surface shape and its array arrangement state on the substrate by engraving the convex array array on the substrate.

The manufacturing method according to claim 2 has a second film forming step in addition to the steps in the manufacturing method according to claim 1.

After the "heating step", the "second film forming step"
Before the "etching step", on the "array array of photosensitive materials having a convex shape" formed in the heating step,
Photosensitive material (may be the same as or different from the photosensitive material in the above film forming step. When the second film forming step is performed by coating, the ratio of the photosensitive material and the thinner should be appropriate. Can be formed again (in the case of film formation by coating, by evaporating volatile components after film formation,
That is, the main component of the photosensitive material is left), and a convex-shaped connection array array in which smooth convex shapes are connected to each other is formed.

In the etching process after the second film forming process, the convex arrayed array array is engraved on the substrate to form a desired refractive surface shape and a continuous array array of refractive surfaces on the substrate.

In the manufacturing method according to claim 3, the substrate is
A microlens having a desired refraction surface shape and its array arrangement state on a substrate by performing the same film forming step, optical patterning step, light irradiation step, heating step, and etching step as in the manufacturing method according to claim 1. Form an array.

A metal mold is prepared by using the substrate in this state as a master mold, or a concave mold is manufactured by further transferring the shape from the above master mold, and the desired mold is formed by resin molding using these molds. A microlens array having the refracting surface shape and the array arrangement state thereof is formed.

In the manufacturing method according to claim 4, the substrate is
A desired refraction surface shape and its connection to the substrate are performed by performing the same film forming step, optical patterning step, light irradiation step, heating step, second film forming step, and etching step as in the manufacturing method according to claim 2. A microlens array having an array arrangement state is formed on a substrate.

A metal mold is prepared by using the substrate in this state as a master mold, or a concave mold is manufactured by further transferring the shape from the above master mold, and the desired mold is formed by resin molding using these molds. A microlens array having the refracting surface shape and the array arrangement state or the connection array state thereof is formed.

According to a fifth aspect of the manufacturing method, the "etching step" is not performed in the third or fourth aspect of the manufacturing method, and an array array or a concatenated array array of the photosensitive material formed on the substrate is used as a mother die. A mold is prepared or formed, and by using these molds, a microlens array having the desired refraction surface shape and its array arrangement state or connection array state is formed by resin molding.

In the etching step of the manufacturing method according to any one of claims 1 to 5, "engraving a convex array array on a substrate" means "forming a substrate having a shape corresponding to the convex array formed of a photosensitive material". Is formed as the surface shape of. The carved shape may be congruent with the shape formed of the photosensitive material, or the height of the convex surface may be different. As dry etching, ECR plasma etching or the like in which oxygen gas or CHF ₃ gas is introduced (ionized gas is ionized, the generated ions are electrically accelerated toward the substrate, and the etching surface collides with the etching surface from a direction orthogonal to the substrate. And a RIE (parallel plate type reactive ion dry etching) are preferable.

In the manufacturing method according to any one of claims 1 to 5, a "primer layer may be provided between the substrate and the layer of the photosensitive material" if necessary (claim 6).

In the manufacturing method according to the first or second aspect, since the microlens array is formed by the substrate itself,
The substrate must be transparent, that is, light-transmissive. However, in the manufacturing method according to claims 3, 4, and 5, the substrate is not necessarily transparent because it is used as a mold master. As the light transmissive material, optical glass, plastic, various transparent crystals, and refractive index distribution material can be used (claim 7).

As an application field of the present invention, a case where the curved surface formed on the substrate by the method according to claim 1 or 2 is used not as a refracting surface but as a "reflecting surface" is conceivable (micromirror). Array), in which case the substrate need not of course be transparent.

In the manufacturing method according to any one of claims 1 to 7, the intensity of light applied to the entire surface of the photo-patterned film in the light irradiation step may be a desired distribution for each lens pattern (claim 8). . The “lens pattern” refers to a film portion corresponding to each microlens in a film pattern formed on a substrate by optical patterning. The shape of the refracting surface formed in the heating process can be controlled by giving a distribution to the intensity of the light radiated for each lens pattern, that is, inside each individual lens pattern. It is possible to manufacture a microlens having a surface. Similarly, in the manufacturing method according to any one of claims 1 to 7, the intensity of light applied to the entire surface of the photo-patterned film in the light irradiation step may be a desired distribution over the entire surface of the film (claim 9). That is, in the pattern of the film patterned on the substrate, the optical characteristics (for example, the focal length) of the microlenses in the microlens array formed by changing the intensity of the irradiated light have a distribution on the substrate. Can be changed by

The microlens array described in claim 10 is the microlens array manufactured by any one of the manufacturing methods described in claims 1-9. An antireflection film can be formed on the refraction surface side and / or the opposite surface side of the microlens array (claim 11). Of course, the lens surface of the formed microlens array may have a free-form surface (claim 12).

Each of the above manufacturing methods can also be used as a method for manufacturing a single microlens. That is, in order to obtain a single microlens, a pattern corresponding to the single microlens may be formed in the optical patterning in each of the above methods (claim 13) or claims 1-9.
The microlens array manufactured by any of the above methods may be separated into individual microlenses by cutting or the like (claim 14). In this way, a microlens is obtained (claim 15).

The microlens and the microlens array according to the present invention may be arranged on the light incident side or the light emitting side of each optical functional element such as a CCD, an LED, a tip of an optical fiber-connector, or an on-chip lens. -It can be formed as an array.

[0028]

1 is a view for explaining the manufacturing method according to the first aspect.

FIG. 1A shows the state after the "film forming step". A film 3 having a uniform thickness made of a heat-deformable photosensitive material is formed on a transparent substrate 1 with a primer layer 2 (claim 6) interposed therebetween. Various photoresists can be used as the heat-deformable photosensitive material, and the film forming method is also appropriate.

FIG. 1B shows the exposure process in the optical patterning process. Patterns to be patterned
A mask (formed by a metal film 5 or the like vapor-deposited on one surface of the transparent substrate 4) having a positive shape as a positive image is aligned and superposed, and ultraviolet rays or the like are radiated through this mask to perform patterning. Exposure. The mask shape corresponding to a single microlens can be circular, elliptical, rectangular, polygonal, or the like.

FIG. 1C shows a state after the optical patterning step. The exposed portion of the film 3 is removed, and the pattern of the film 3 of the photosensitive material left on the substrate 1 corresponds to the pattern image on the mask. In the exposure step (FIG. 1B), the exposure pattern can be slightly different from the mask pattern by providing a space between the mask and the film 12 and adjusting the space. In the above pattern of the film 3, the pattern portion corresponding to each microlens is the above-mentioned “lens pattern”.

In the state of FIG. 1C, a light irradiation step is performed on the film 3 which is photo-patterned as shown in the drawing,
The entire patterned film 3 is illuminated with light. The energy of the light irradiated by this light irradiation cuts the linear molecules in the film 3, the ratio of the linear molecules in the film decreases, and the van der Waals force between the molecules in the film decreases.

Therefore, the film 3 that has been subjected to the light irradiation process has an increased solubility, the fluidity is increased during the heating process, and the thermal deformability is improved.

Therefore, a heating step is performed after the light irradiation step,
When the film 3 is heated above the heat deformation temperature, the photosensitive material 3A having a smooth convex surface with the corners of the film 12 rounded due to the effect of the heat deformability and surface tension of the softened photosensitive material.
It is possible to realize the state where the arrays are arranged. FIG. 1D shows this state.

Next, in the state of FIG. 1D, dry etching is performed as an etching step on the surface where the convex surfaces are arrayed. The action of etching is the photosensitive material 3
It acts on the convex shape of A and the primer 2 and the substrate 1. In the etching process, the convex array array is formed on the substrate 1.
It is performed until it is carved as the surface shape of.

In FIG. 1 (e), the solid line shows the state after the etching process is completed, and the broken line shows the state before the etching process. Thus, the microlens array 1A is obtained by the transparent substrate material having the surface shape in which the desired refracting surface shape is arrayed.

Here, the operation of the above "light irradiation step" will be described. As described above, the light irradiation step is performed to cut the linear molecule in the patterned film 3 to enhance the fluidity of the film.

The size of the "lens pattern", which is one unit of the patterned film 3, has a certain size (for example, 100 μm).
If the heating step is performed without performing the light irradiation step in the case where the film 3 is large and the thickness of the film 3 is small, the thermal deformation agent is insufficient depending on the material of the film 3 and the “edge” of the lens pattern is not obtained. Although the part (1) is rounded by thermal deformation, the flatness of the film 3 remains in the central part of the lens, or the central part has a concave shape, so that a good refracting surface shape cannot be formed.

However, if the light irradiation step is performed and the heating step is performed in a state where the intermolecular force in the film is weakened, the thermal deformability is increased. Therefore, even in the above case, the smooth and good convex surface shape is obtained. Can be formed.

FIG. 2 shows the steps after the second film forming step in the manufacturing method according to the second aspect. In the case of the manufacturing method described with reference to FIG. 1, generally, after the heating step, the individual photosensitive materials 3A in the array arrangement of the photosensitive material 3A having a smooth convex surface are separated from each other. Therefore, when the microlens array is formed by performing the etching process in this state, the refracting surfaces formed on the surface of the substrate material are also separated from each other, and the "space" portion (refractive power (The part which does not have) does not have a lens effect, and the light incident on the space part is not affected by the lens function, so that the light utilization efficiency as a microlens array becomes inversely proportional to the area ratio occupied by the space part. .

According to the manufacturing method of the second aspect, FIG.
After the heating step shown in (1), a film 3B is formed again from the same or different photosensitive material on the array of the photosensitive material 3A having a smooth convex surface on the substrate surface (second film forming step). When heating is performed after forming the film 3B in this way, as shown in FIG. 2A, a connected array array of convex surfaces in which smooth convex shapes are connected to each other is obtained.

Subsequently, an etching process is performed by dry etching to obtain a microlens array 1B having refraction surfaces connected to each other in accordance with the connection array arrangement of the convex surfaces.

If a microlens array 1A shown in FIG. 1 or the microlens array 1B shown in FIG. 2 is used as a mother die to form a die by a known method, and a plastic molding process is performed using the die, a plastic micro The lens array can be easily mass-produced. In this case, a non-transparent substrate can be used as the substrate 1. The convex shape of the matrix is a refraction surface in consideration of the refractive index of the resin. Alternatively, it is also possible to fabricate a microlens array by resin molding using a concave metal mold prepared by further transferring the shape from the mother mold.

As shown in FIG. 3A, when the intensity of the light irradiated in the light irradiation step is distributed to each lens pattern over the entire surface of the photo-patterned film (in the example of the figure, the lens pattern Light having high intensity is applied to the central portion and the peripheral portion), and the fluidity has a distribution depending on the location inside each lens pattern. Therefore, after the heating step, as shown in FIG. It is possible to obtain an array of the photosensitive material 3C having a convex shape of "aspherical shape" according to the distribution of the fluidity.

Further, as shown in FIG. 4A, when the intensity of the light irradiated in the light irradiation step is distributed over the entire surface of the photo-patterned film (in the example of the figure,
The light intensity is high in the central portion of the substrate 1 and small in the peripheral portion.) In the heating process, the thermal deformability is higher than that of the lens pattern in the central portion of the substrate.
As shown in (b), it is possible to obtain an array of the photosensitive material 3D in which the curvature of the surface of each lens pattern film becomes smaller toward the center of the substrate.

In the fabrication of the microlens array or the master mold for the microlens array described above, the shape of the convex surface (convex surface engraved on the substrate material) that determines the refraction surface of the lens is a major factor. Is a function of.

That is, the factors that influence the shape are:
First, the film thickness of the film 12 of the photosensitive material formed by the film forming process on the substrate, secondly, the width of the light transmitting portion of the mask and the pattern shape of the mask, and thirdly in the light patterning. The distance between the mask and the film of the photosensitive material, fourth, the amount of light energy given to the film in the light irradiation step and its distribution, and fifth, the heating temperature in the heating step (the thermal deformability and surface tension of the softened photosensitive material). Changes with temperature), sixthly, in the case of the manufacturing method according to claim 2, seventhly, the thickness of the film 13 formed by the second film-forming step, and seventhly, selective ratio between the photosensitive material and the substrate in the etching step. Etc. can be given.

Therefore, the above factors are optimized so that the shape of the convex surface finally formed on the substrate material becomes a desired shape.

[0049]

EXAMPLES Specific examples will be described below.

Example I (LCD having an arrangement pitch of liquid crystal pixels of 150 μm in the longitudinal direction and 100 μm in the lateral direction)
Microlens Array for Panel) As is well known, an LCD (liquid crystal) panel is an array of a large number of minute liquid crystal pixels closely arranged in a plane.
Since the light incident on the FT and the wiring region is not used, the light use efficiency is only 30 to 40% when used as it is. By providing microlenses for condensing corresponding to the arrangement pitch of the liquid crystal pixels of the LCD panel,
In order to improve the utilization efficiency of light, a microlens array arranged in a plane is manufactured.

Thickness: 1 mm After thoroughly cleaning the quartz substrate,
A primer is applied to the surface thereof, and a positive photoresist (positive resist OFPR-800-50 manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a heat-deformable photosensitive material is applied onto the surface thereof by a spinner, and a pre-coat is applied. Then, a film having a thickness of 2.2 μm was obtained. (Film Forming Step) Next, a photomask having a pattern in which light-shielding rectangular shapes of 140 μm in the longitudinal direction and 90 μm in the lateral direction are arranged at a pitch of 150 μm in the longitudinal direction and a pitch of 100 μm in the lateral direction is used as the film. Was superposed on each other and exposed to ultraviolet rays, and then developed according to the developing method of photolithography to optically pattern the film (optical patterning step).

Subsequently, a predetermined amount of light is uniformly irradiated on the entire surface of the film of the photosensitive material which has been patterned by optical patterning, and then it is heated to 260 ° C. which is higher than the heat deformation temperature to perform post baking. (Light irradiation process / heating process). as a result,
The film having a rectangular cross-section had a smooth convex shape, and the height of the apex from the substrate was 3.0 μm.

Then, an etching process was carried out by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The selectivity or etching rate is the film of photosensitive material:
Quartz substrate = 1: 1. As a result, the smooth convex surface shape was engraved in a congruent shape on a quartz substrate, and a desired microlens array was obtained. Each formed micro lens has a size (dimension) of 140 × 90 μm and a height of 3.
They had a smooth convex shape of 0 μm and were separated from each other by a distance of 10 μm.

For comparison, when the heating step is performed without the light irradiation step after the photo-patterning step, the shape of the photosensitive material after thermal deformation is a shape in which the central portion is recessed, which is the desired shape. It was not possible to obtain a smooth convex surface shape.

Example-II (LC in which the arrangement pitch of liquid crystal pixels is 200 μm in the longitudinal direction and 130 μm in the lateral direction)
Microlens array for D panel) Thickness: 1mm quartz substrate is thoroughly washed, primer is applied on the surface, and positive type photoresist (Tokyo Ohka Kogyo Co., Ltd.) is used as a heat-deformable photosensitive material. Positive resist OFPR-800-50 manufactured by Co., Ltd. was applied by a spinner and prebaked to obtain a film having a thickness of 3.6 μm.

Next, the longitudinal direction: 190 μm, the lateral direction:
120μm light-shielding rectangular shape is 200μ in the longitudinal direction
A photomask having a pattern arranged at a pitch of m and a pitch of 130 μm in the lateral direction is superposed on the film with a gap of 70 μm, exposed to ultraviolet light, and then developed according to a developing method of photolithography to expose the film to light. Pattern
I learned.

Then, a predetermined amount of light is uniformly irradiated onto the entire surface of the photo-patterned film of the photosensitive material to perform a light irradiation step, and thereafter, it is heated to 260 ° C. which is higher than the heat deformation temperature to post-bak. went. As a result, the film having a rectangular cross section had a smooth convex shape, and the height of the apex from the substrate was 5.0 μm.

Subsequently, an etching process was performed by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The etching rate is a film of a photosensitive material: quartz substrate =
It is 1: 1. As a result, the smooth convex surface shape was engraved in a congruent shape on a quartz substrate, and a desired microlens array was obtained. Each of the formed microlenses had a smooth convex shape with a size (dimension) of 190 × 120 μm and a height of 5.0 μm, and was separated from each other at an interval of 10 μm.

Example-III (L in which the arrangement pitch of liquid crystal pixels is 150 μm in the longitudinal direction and 100 μm in the lateral direction)
Microlens array for CD panel) Thickness: 1mm quartz substrate is thoroughly washed, primer is applied on the surface, and positive type photoresist (Tokyo Ohka Kogyo Co., Ltd.) is used as a heat-deformable photosensitive material. Positive resist OFPR-800-50 manufactured by Co., Ltd. was applied by a spinner and prebaked to obtain a film having a thickness of 2.8 μm.

Optical patterning was performed using the same mask as in Example-I, and the light irradiation step and the heating step were performed under the same conditions as in Example-I. As a result, the film having a rectangular cross section was found. The surface was a smooth convex surface, and the height of the apex from the substrate was 3.9 μm.

Subsequently, an etching process was performed by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The etching rate is a film of photosensitive material: quartz substrate ≒
It is 1: 0.795. As a result, the smooth convex surface shape was engraved on the quartz substrate in substantially the same shape, and a desired microlens array was obtained. Each formed microlens has a size (dimension) of 140 × 90 μm and a height of 3.
They had a smooth convex shape of 1 μm and were separated from each other by a distance of 10 μm.

Example IV (LC in which the liquid crystal pixel array pitch is 150 μm in the longitudinal direction and 100 μm in the lateral direction)
Microlens array for D panel) Thickness: 1mm quartz substrate is thoroughly washed, primer is applied on the surface, and positive type photoresist (Tokyo Ohka Kogyo Co., Ltd.) is used as a heat-deformable photosensitive material. Positive resist OFPR-800-50 manufactured by Co., Ltd. was applied by a spinner and prebaked to obtain a film having a thickness of 2.8 μm.

Optical pattern using the same mask as in Example I
As a result of performing the light irradiation step and the heating step under the same conditions as in Example-I, the film whose individual cross-sectional shape was rectangular has a smooth convex shape, and the height from the substrate at the apex is high. Was 3.9 μm. Subsequently, a mixture of the positive photoresist and thinner (mixing ratio: photoresist: thinner = 1: 0.5) is applied onto the formed convex shape (second film forming step). As a result of heating again at 260 ° C., each convex portion has a continuous and smooth convex surface shape, and the height of each apex is reduced by 0.5 μm to 3.4 μm.

Next, an etching process was performed by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The etching rate is a film of photosensitive material: quartz substrate ≒
1: 0.765. As a result, the smooth convex surface shape was engraved on the quartz substrate in substantially the same shape, and a desired microlens array was obtained. Each formed micro lens has a size (dimension) of 150 × 100 μm and a height: 2.
It was possible to obtain a microlens array having a smooth convex shape of 6 μm and having a high light utilization efficiency of light densely arranged while being continuous with each other. The "light irradiation step" in the above Examples I to IV uses a high pressure mercury lamp and a wavelength: 350 to.
Near-ultraviolet light including light in the 450 nm region is emitted at a wavelength of 403
The irradiation was performed so that the integrated irradiation amount of the light of nm was about 600 mJ / cm ² .

Example-V (microlens array for condensing lens, in which focal length is changed in the substrate) A quartz substrate having a plate thickness of 1 mm was washed in the same manner as in Example-I,
Positive photoresist as a primer and a heat-deformable photosensitive material (Positive resist O manufactured by Tokyo Ohka Kogyo Co., Ltd.)
FPR-800-300) was applied by a spinner and prebaked to obtain a film of a heat-deformable photosensitive material having a thickness of 8 μm.

Next, after performing optical patterning using a photomask having the same pattern as in Example-I, a desired mask is provided by interposing a mask having a distribution of the light blocking rate in the optical path of the irradiation light. After the intensity distribution state was created and the integrated irradiation amount of the light energy in the central portion and the peripheral portion of the substrate was changed, the light irradiation step was performed, and then the heating step was performed.

The above "light irradiation step" is the same as in Examples-I to IV.
Using the same high-pressure mercury lamp as in the light irradiation step, the cumulative irradiation amount for light having a wavelength of 403 nm is from 0 mJ / cm ² to 1000 from the substrate peripheral portion to the substrate central portion.
It was irradiated with near-ultraviolet light so as to monotonously change to mJ / cm ² .

As a result, the film whose individual cross-sectional shape was rectangular has a smooth convex shape, and the thermal deformation amount of the photosensitive material changes according to the light irradiation amount. 9.1 μm to 1 from the periphery to the center
It was gradually changed to 1.4 μm.

Subsequently, an etching process was performed by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The etching rate is a film of photosensitive material: quartz substrate ≒
It is 1: 1. As a result, a smooth convex surface shape was engraved on the quartz substrate in substantially the same shape, and a desired microlens array was obtained. Each formed microlens has a size (dimension) of 140 × 90 μm, a height of 9.1 μm at the peripheral portion of the substrate and 11.4 μm at the central portion of the substrate, and the focal length is sequentially from the central portion of the substrate to the peripheral portion. It was possible to obtain a “focal length distribution type” microlens array that is long.

In the optical patterning process, a method using a photomask in which the shape of the pattern is changed between the center and the periphery of the substrate and the amount of light energy applied in the light irradiation process are changed on the substrate surface. By using this method together with the method described above, a microlens array in which the focal length is further changed within the same substrate can be produced.

Example VI (microlens array in which microlenses are aspherical lenses) A quartz substrate having a plate thickness of 1 mm was washed in the same manner as in Example I, and
A positive photoresist (a positive resist OF manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a primer and a heat-deformable photosensitive material.
PR-800-300) was applied on a spinner and prebaked to obtain a film of a thermally deformable photosensitive material having a thickness of 7.4 μm.

After performing optical patterning using a photomask of the same pattern as in Example I, a mask having a light blocking property is interposed in the optical path of the irradiation light, and the central portion of each lens pattern is interposed. The light irradiation step was performed so that the irradiation light intensity was increased in the peripheral portion, and then the heating step was performed.

In the "light irradiation step", the same high pressure mercury lamp as in the light irradiation step of Examples-I to IV was used, and the wavelength was 4
The near-ultraviolet light was irradiated so that the integrated irradiation amount of the light of 03 nm was 500 mJ / cm ² at the peripheral portion and the central portion of each lens pattern.

As a result, in the film whose individual cross-sectional shape was rectangular, the amount of thermal deformation of the photosensitive material changed depending on the light energy-irradiation amount, and therefore two smooth convex shapes were formed. It had an aspherical shape (see FIG. 3B), and its height was 7.7 μm at the center of the pattern and 8.8 μm at the apex of the smooth convex surface.

Subsequently, an etching process was performed by ECR plasma etching using oxygen and CHF ₃ as introduction gases. The etching rate is a film of photosensitive material: quartz substrate ≒
It is 1: 1. As a result, the smooth convex surface shape was engraved on the quartz substrate in substantially the same shape, and a desired microlens array was obtained. Each formed micro lens,
The size (dimension) is 140.times.90 .mu.m, and the height from the substrate is 7.7 .mu.m at the center of the pattern, and the apex of the smooth convex surface is 8.8 .mu.m.

[0076]

As described above, according to the present invention, it is possible to provide a novel microlens, a microlens array and a manufacturing method thereof. Since the manufacturing method of the present invention is configured as described above, it is possible to easily and reliably manufacture a microlens and a microlens array having a large lens diameter of 100 μm or more and a long focal length. Particularly, in the method according to claims 2 and 4, individual microlenses can be connected to each other to manufacture a microlens array with high light utilization efficiency. In the method according to claim 7, laser light, X-rays and the like can be produced. It is possible to provide a microlens that can be effectively used even for high energy light. Furthermore, according to the manufacturing method of claims 8 and 9, it is possible to manufacture an array of microlenses having a lens surface of an aspherical shape, or a microlens array having different optical characteristics in the same array. The microlens array and microlens have good light utilization efficiency.

[Brief description of drawings]

FIG. 1 is a drawing for explaining the manufacturing method according to claim 1.

FIG. 2 is a diagram for explaining the manufacturing method according to claim 2;

FIG. 3 is a diagram for explaining the manufacturing method according to claim 8;

FIG. 4 is a drawing for explaining the manufacturing method according to claim 9;

[Explanation of symbols]

 1 transparent substrate 2 primer 3 film of heat-deformable photosensitive material 4 substrate of mask 5 metal film of mask

Claims (15)

[Claims] 1. A film having a uniform thickness made of a heat-deformable photosensitive material is formed on a transparent substrate, and the film is formed according to a pattern corresponding to each lens in the microlens array to be formed and its arrangement. By light patterning, the entire surface of the photo-patterned film is irradiated with light,
The linear molecules in the film are cut, and the film irradiated with light is heated to the heat deformation temperature, and due to the heat deformability and surface tension of the photosensitive material, an array array of photosensitive materials with a smooth convex shape is formed. Then, dry etching is performed on the surface on which the array array is formed and the convex array array is engraved on the substrate to form a desired refractive index surface shape and its array array state on the substrate. A method of manufacturing a microlens array, comprising: 2. A film having a uniform thickness made of a heat-deformable photosensitive material is formed on a transparent substrate, and the film is formed according to a pattern corresponding to each lens in the microlens array to be formed and its arrangement. By light patterning, the entire surface of the photo-patterned film is irradiated with light,
The linear molecules in the film are cut, and the film irradiated with light is heated to the heat deformation temperature, and due to the heat deformability and surface tension of the photosensitive material, an array array of photosensitive materials with a smooth convex shape is formed. And re-form a film of photosensitive material on the array array,
By vaporizing the volatile components, a convex-shaped connecting array array in which the smooth convex shapes are connected to each other is formed, and dry etching is performed on the surface on which the connecting array array is formed, and the convex-shaped connecting A method of manufacturing a microlens array, comprising engraving an array array on the substrate to form an array array state in which refractive surfaces having a desired refractive index surface shape are continuous with each other on the substrate. 3. A film of uniform thickness made of a heat-deformable photosensitive material is formed on a substrate, and the film is optically patterned according to a pattern corresponding to each lens and its arrangement in a microlens array to be formed. -Irradiate the entire surface of the above photo-patterned film by
The linear molecules in the film are cut, and the film irradiated with light is heated to the heat deformation temperature, and due to the heat deformability and surface tension of the photosensitive material, an array array of photosensitive materials with a smooth convex shape is formed. Then, dry etching is performed on the surface on which the array arrangement is formed, and by engraving the convex shape and the array arrangement state on the substrate, the desired refractive index surface shape and the array arrangement state are formed on the substrate. The desired refracting surface shape and its array are formed by resin molding using a die formed by using the substrate in this state as a mother die or a concave die formed by further transferring the shape from the mother die. A method of manufacturing a microlens array, which comprises forming a microlens array having an array state. 4. A film of uniform thickness made of a heat-deformable photosensitive material is formed on a substrate, and the film is optically patterned according to a pattern corresponding to each lens and its arrangement in a microlens array to be formed. -Irradiate the entire surface of the above photo-patterned film by
The linear molecules in the film are cut, and the film irradiated with light is heated to the heat deformation temperature, and due to the heat deformability and surface tension of the photosensitive material, an array array of photosensitive materials with a smooth convex shape is formed. And re-form a film of photosensitive material on the array array,
A volatile component is vaporized to form a convex-shaped connecting array array in which smooth convex shapes are connected to each other. Dry etching is performed on the surface on which the connecting array array is formed, and the convex shape and its connection are formed. By engraving the array arrangement state on the substrate, a desired refracting surface shape and its connected array arrangement state are formed on the substrate, and a die formed using the substrate in this state as a mother die, or further from the mother die It is possible to form a microlens array in which individual microlenses are continuous with each other having the desired refraction surface shape and the connected array arrangement state by resin molding using a concave-shaped mold produced by transferring the shape. A method for manufacturing a characteristic microlens array. 5. The manufacturing method according to claim 3 or 4,
This mold is formed by using a mold manufactured by using an array array or a connected array array formed of a photosensitive material on a substrate as a master mold, or a concave mold manufactured by further transferring the shape from the master mold. A method of manufacturing a microlens array, which is characterized by forming a microlens array having a desired refracting surface shape and its array arrangement state or connected array arrangement state by resin molding. 6. The method of manufacturing a microlens array according to claim 1, 2 or 3 or 4 or 5, wherein a primer layer is provided between the substrate and the layer of the photosensitive material. 7. The manufacturing method according to claim 1, 2 or 3 or 4 or 5 or 6, wherein the substrate is quartz, various optical glasses, ceramics, various single crystals, or a gradient index material. A method for manufacturing a characteristic microlens array. 8. The manufacturing method according to claim 1, 2 or 3 or 4 or 5 or 6 or 7, wherein the intensity of light applied to the entire surface of the photo-patterned film is:
A method for manufacturing a microlens array, characterized in that each lens pattern has a desired distribution. 9. The manufacturing method according to claim 1, 2 or 3 or 4 or 5 or 6 or 7, wherein the intensity of light applied to the entire surface of the photo-patterned film is:
A method for manufacturing a microlens array, characterized by providing a desired distribution on the entire surface of the film. 10. A microlens array manufactured by the manufacturing method according to claim 1, 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9. 11. The microlens array according to claim 10, wherein an antireflection film is formed on the refraction surface side and / or the opposite surface side. 12. The microlens array according to claim 7, wherein the lens surface is a free-form surface. 13. The method for producing a microlens array according to claim 1, 2 or 3 or 4 or 5 or 6 or 7 or 8, wherein a pattern corresponding to a single microlens is photopatterned in the photopatterning step. A method for manufacturing a microlens, which comprises manufacturing a single microlens. 14. A microlens array manufactured by the method for producing a microlens array according to claim 1, 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9, wherein each microlens is separated from each other. Microlens manufacturing method 15. A microlens manufactured by the manufacturing method according to claim 13.