JP5044384B2 - Optical element and optical functional element - Google Patents

Description

  The present invention relates to an optical element and an optical functional element.

  For example, a “microlens array for effectively condensing light on individual liquid crystal pixels” is usually used for a liquid crystal panel, but such a microlens array generally has a microlens surface formed. The other side surface is integrated with a “flat surface of another member” at a predetermined interval. For this reason, it is necessary to form a flat surface to be integrated with another member on the side where the microlens surface is formed.

  In order to form such a flat surface, conventionally, a parallel plate-like transparent substrate is bonded to the surface on which the microlens surface is formed, and the transparent substrate is thinned by polishing to obtain a desired thickness. In other words, it was joined and integrated with another member on the polished surface.

  However, in this method, “a large part of the thickness direction of the transparent substrate is scraped off by polishing”, the waste of the transparent substrate material is large, and the polishing takes time and the working efficiency is not good. Improvements are desired in terms of material costs, work efficiency, and the environment.

  The flat surface is formed for integration with the flat surface of another member, and an appropriate coating material can be applied in a liquid state to form a coating layer having a flat surface. There is no waste of materials and work is efficient.

  By the way, an optical member such as a microlens array is generally an “optical functional area” in which micro optical surfaces such as microlenses are formed as an array arrangement pattern, and a flat area having a flat surface provided in contact with the optical functional area. And have. As described above, when coating is performed on the optical member in which the optical functional region and the flat region are in contact with each other by a conventional coating method such as spin coating, the optical functional region and the surface of the coating layer formed by coating are formed. There is a problem that a “step” is generated at the boundary with the flat region, and the surface of the coat layer is “not one flat surface”.

This problem will be described with reference to FIG. In FIG. 1, an optical member denoted by reference numeral 1 is formed by forming a microlens array (optical function area) MLA and a flat area FD on one surface of a substrate. Reference numeral 2 denotes a coating layer formed by applying a coating material in liquid form.
As shown in the figure, on the free surface of the formed coat layer 2, a step of height: h is formed corresponding to the boundary portion between the microlens array MLA and the flat region FD. "
Conventionally, no proposal has been made to solve such a problem as far as the inventors know.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize a novel optical element in which a “coat layer whose surface is a single plane” is formed in the optical functional region and the flat region.

The optical element of this invention has an optical functional element and a coat layer.
The “optical functional element” has an optical functional region and a flat region on at least one surface.
The “optical functional area” is an area in which the micro optical surface is formed as an array arrangement pattern, and the array arrangement pattern of the micro optical surface has an optical function.

The “micro optical surface” is, for example, a micro lens or a micro prism.
The array arrangement pattern on the micro optical surface may be a one-dimensional array pattern or a two-dimensional array pattern.

The “flat region” is provided in contact with the optical function region and has a flat surface. The flat region is formed, for example, surrounding the optical function region so as to frame the optical function region.
The “optical functional element” has an optical functional region and a flat region integrally made of the same material.

  The “coat layer” is a layer obtained by coating a predetermined amount of a coating material in a liquid state on the “optical function region and flat region” of the optical function element. The coating layer is in a state where the coating material applied in a liquid state is in a state where it does not flow at least freely.

  For example, an “inorganic sol-gel material” can be used as a coating material, and this sol-gel material is applied in a liquid state, that is, in a sol state, and is gelled by light and / or heat, or further solidified. The thing of a state can be made into a "coat layer."

The optical element of the present invention includes the optical functional element and the coating layer as described above, and has the following characteristics.
That is, in the optical element of claim 1, “a convex micro optical surface having a height of H is formed as an array arrangement pattern” in the optical function area formed on at least one surface, and the optical function area in the optical function element A flat region is formed to be lower by a step amount: ΔH (0 <| ΔH | <H) than the flat surface in contact with the top of the convex micro optical surface.
Then, this step amount: [Delta] H is, after coated by applying a coating material of a predetermined amount, is set such that the total optical function area and the flat region and the coated free surface of the coating layer forms a single plane Yes.
Further, in the optical element according to claim 2, an optical functional area formed on at least one surface is “a concave micro optical surface having a depth of H is formed as an array arrangement pattern”, and the optical functional area in the optical functional element A flat region is formed higher by a step amount: ΔH (0 <ΔH <| H |) than the flat surface in contact with the most concave portion of the concave micro optical surface.
Then, this step amount: [Delta] H is, after coated by applying a coating material of a predetermined amount, is set such that the total optical function area and the flat region and the coated free surface of the coating layer forms a single plane Yes.
Of course, “one plane” is not a strict one plane but a plane having flatness that can be used as an optical element without any problem.

In the optical element according to claim 1 or 2 , the “coating material” is preferably an inorganic material ( claim 3 ). When the coating layer is composed of an inorganic coating material, the coating layer can be firmly integrated with the optical functional element without using an adhesive, the durability is improved, and there are problems such as the occurrence of retardation specific to the case of using an organic material. Can be avoided.

The coating layer in the optical element according to claim 1, 2 or 3 can be “coated and formed using a spin coater, a bar coater, a slit coater or a flow coater in a liquid state” ( claim 4 ). Of course, the coating is not limited to this, and other coaters may be used.

It can be one-dimensional or two-dimensional microlens array to the "optical function area in the optical functional element" of the optical element according to any one of claims 1 to 4 is formed (claim 5). The microlens forming the microlens array may be a “convex microlens surface” or “concave microlens surface”, and the lens surface shape may be a spherical surface, an aspherical surface, an “anamorphic surface” such as a cylindrical surface, an axicon lens surface, etc. it can. Of course, the present invention is not limited to this, and it may be an array arrangement pattern of various conventionally known micro optical surfaces such as a microprism array.

The “optical function element” of the present invention is an optical function element used in the configuration of the optical element according to any one of claims 1 to 5 (claim 6). That is, the “optical functional element” has at least one optical functional region in which micro optical surfaces are formed as an array arrangement pattern, and a flat region that is provided in contact with the optical functional region and has a flat surface. , optical function area and a flat area and said step amount: has a [Delta] H, this step amount: [Delta] H is, after coating by applying a coating material of a predetermined amount, the coating layer coated on the optical function area and the flat area The entire free surface is set to form a plane.

  This invention is based on the knowledge obtained through the inventors' research. When the inventors applied the optical member in which the optical functional region and the flat region are in contact with each other by a coating method such as spin coating, the “optical functional region and the surface of the coating layer formed by coating”. The nature of the “step generated at the boundary with the flat region” was investigated. The size of the step depends on the amount of step between the optical functional region and the flat region in the optical functional element before forming the coat layer: ΔH. Therefore, by “adjusting the step height: ΔH in advance”, the free surface of the formed coating layer can be made “a flat surface without a step”, and this property can be applied to coating materials and “application It was found that it does not depend on "method". Based on this knowledge, it was possible to realize an optical element having a coating layer having a free surface as a flat surface without a step as in the embodiments described later.

  In addition, if the amount of the material is too small when applying with the coating material, the form of the optical functional region or flat region of the optical functional element appears on the surface shape of the coating layer. There must be enough to form a “plane”.

  The “predetermined amount” of the coating material to be “applied in a liquid state” means that the amount is sufficient to form the above “one plane”. It is determined by the shape of the micro optical surface formed in the functional region and the state of the array arrangement pattern.

  In other words, if the step height: ΔH is not set appropriately, a step appears on the free surface of the coat layer even if the coating material is applied in an increased amount.

  As described above, according to the present invention, a novel optical element and optical functional element can be realized. According to the present invention, by using the optical functional element of the present invention, an optical element in which the free plane of the coating layer forms “one plane without a step” can be realized, and joining with another member is easy.

The embodiment will be described with reference to FIG.
In FIG. 2A, reference numeral 10 indicates an optical functional element.
The optical functional element 10 has a parallel plate shape and is formed of a transparent material such as a quartz substrate. An optical functional area 10A is formed on one side as an array arrangement pattern of micro optical surfaces, and is in contact with the optical functional area 10A. ”Is formed.

The optical functional element 10 has the same optical functional area 10A, and four types (ΔH = 0.0 .mu.m, 0.7 .mu.m, 1... 5 μm, 3.0 μm).
A “convex microlens array arrangement pattern” was formed in the optical function area 10A. In other words, 1024 microlenses having a height of 3 μm were arranged in a square matrix at a pitch of 10 μm in the horizontal direction and 1024 in the vertical direction.

Step height: ΔH is the surface of the optical functional area 10A (surface in contact with the top of the microlens)
2 is measured toward the flat portion of the flat region 10B, and when measured downward in FIG. Therefore, for example, when ΔH = 0, the surface in contact with the top of the microlens and the flat portion of the flat region 10B are at the same height, and when ΔH = 3 μm, the surface in contact with the top of the microlens. However, it is located “3 μm above” the flat part of the flat region.

Various coating materials were applied to these four types of optical functional elements by a spin coating method to form a coating layer.
FIG. 2B shows a state in which the coat layer 12 is formed.
When the coating layer 12 was formed on the above four types of optical functional elements, the relationship between the step size formed on the coating layer 12: Δh and the step amount: ΔH was examined. It became as shown in. That is, it was found that the step size: Δh decreases linearly with the increase in the step amount: ΔH shown on the horizontal axis of FIG.

  For example, when the step amount is ΔH = 0, that is, when the flat portion of the flat region 10B and the surface in contact with the top of the microlens in the optical function region 10A are “same height”, the coating layer 12 is generated. Step size: Δh = 1 μm. From this, the following can be understood.

That is, when the area equal to the area (10 μm × 10 μm) allocated to one microlens of the microlens array in the optical function area 10A is considered in the flat area 10B, the step size is 1 μm after the formation of the coat layer 12. This means that when the coating material is applied, a coating material of “10 × 10 × 1 μm ³ ” is formed on the surface of the microlens and the surface in contact with the top of the area allocated to one microlens. This is considered to be because the gap area is filled.

  Therefore, in general, as shown in FIG. 3, in the area area allocated to one microlens in the optical function area, the volume of the “gap area” formed by the surface of the microlens and the surface in contact with the top thereof: ΔV1 Then, the step amount: ΔH may be determined so that the volume “ΔV2” of the “coating material applied on the area allocated to one microlens” considered on the flat region 12B becomes equal. Actually, ΔV1 = ΔV2 does not have to be strictly satisfied, and even when ΔV1≈ΔV2, a coat layer having a “free surface substantially free of steps in one plane” is obtained.

  In the example in the description, if the optical function element is formed so that the step amount is ΔH = 1 μm (that is, the flat portion of the flat region 10B is 1 μm lower than the surface in contact with the top of the microlens), the coating is formed. The size of the step on the surface of the coated layer is Δh = 0, and a coating layer having “a flat free surface with no step” can be formed, and a desired optical element can be obtained.

  When a coat layer was formed by applying a predetermined amount of various coating materials to an optical functional element having a step height of ΔH = 1 μm, the free surface of the coat layer became “a flat surface without a step”. .

  In the example described above, a case where a convex microlens array is formed in the optical functional area is shown. However, the mechanism for generating a step on the free surface of the coat layer is exactly the same as described above. The amount of coating material applied to the flat area having the same area as that allocated to one of the various micro optical surfaces formed in the functional region, and the amount of application of the micro optical surface region having the above area The step amount ΔH may be set so that the two are substantially equal.

  For example, if the micro optical surface formed in the optical functional area is, for example, a “concave micro lens”, the height difference between the surface of the concave micro lens contacting the most concave portion and the flat portion of the flat area In this case, the flat portion of the flat area is set higher than the surface of the optical function area that contacts the most concave portion of the lens surface.

  Finally, the production of the optical functional element as described with reference to FIG. 2 will be briefly described.

  FIG. 4A shows a state in which a photoresist layer 120 is formed on a transparent parallel plate 100 serving as an optical functional element. In this state, the photoresist layer is exposed / developed / superheated, and the resist shape region 120A corresponding to the convex micro-lens surface array due to the thermal flow of the resist, and the flat portion (corresponding to the flat region) 120B in contact with this (B) is obtained, and the surface shape of the photoresist layer 120A is transferred as the surface shape of the transparent parallel plate 100 by dry etching, thereby obtaining a desired optical functional element. it can.

FIG. 5 shows another method for manufacturing the optical functional element.
FIG. 5A shows a state in which a thin chrome layer 102 is formed on a transparent parallel plate 100 serving as an optical functional element. A photoresist layer 104 is formed on the chromium layer 102 (b), and exposure / development is performed to remove the photoresist layer 104 in the “portion serving as an optical functional region” (c). The remaining portion of the photoresist layer 104 corresponds to “a portion to be a flat layer”.

  Next, wet etching is performed to remove the chromium layer 102 in the “portion serving as an optical functional region” as shown in FIG. 5D, and the photoresist layer 104 on the chromium layer 102 is ashed and removed ( e) A photoresist layer 106 is formed again (f). The photoresist layer 106 is exposed, developed and overheated to form a resist-shaped region corresponding to the convex micro-lens surface array by the thermal flow of the resist, and the chrome layer 102 is left on the flat portion in contact therewith (g) .

Subsequently, while the surface shape of the photoresist layer 106 is transferred as the surface shape of the transparent parallel plate 100 by dry etching, the chromium layer 102 is removed by etching and the etching is further advanced to form a “flat region”. In this way, a desired optical functional element can be obtained as shown in FIG.
In FIG. 4C and FIG. 5H, the flat region is substantially flush with the bottom of the convex micro optical surface that constitutes the optical function portion. The surface is set to a surface that is slightly higher than the position shown in the figure .

It is a figure for demonstrating the subject of invention. It is a figure for demonstrating an optical element. It is a figure for demonstrating the principle of invention. It is a figure for demonstrating the manufacturing method of an optical function element. It is a figure for demonstrating another manufacturing method of an optical function element.

Explanation of symbols

10 optical functional element 10A optical functional area 10B flat area ΔH step amount
12 Coat layer

Claims (6)

An optical functional region in which convex micro optical surfaces having a height of H are formed as an array arrangement pattern on at least one surface and a flat region having a flat surface provided in contact with the optical functional region are made of the same material An optical functional element integrally having
A coating layer in which a predetermined amount of a coating material is applied in a liquid state and coated on the optical functional region and the flat region of the optical functional element;
The flat region is formed as low as the step amount: ΔH (0 <| ΔH | <H) with respect to the flat surface in contact with the top of the convex micro optical surface of the optical functional region in the optical functional element,
The step amount: [Delta] H is, after coated by applying the coating material of the given amount, the entire of the optical function area and the free surface of the applied coating layer and the flat area is set so as to form a single plane An optical element. An optical functional region in which concave micro optical surfaces having a depth of H are formed on at least one surface as an array arrangement pattern, and a flat region having a flat surface provided in contact with the optical functional region, are made of the same material. An optical functional element integrally having
A coating layer in which a predetermined amount of a coating material is applied in a liquid state and coated on the optical functional region and the flat region of the optical functional element;
The flat region is formed higher by a step amount: ΔH (0 <ΔH <| H |) than the flat surface in contact with the most concave portion of the concave micro optical surface of the optical functional region in the optical functional element,
The step amount: [Delta] H is, after coated by applying the coating material of the given amount, the entire of the optical function area and the free surface of the applied coating layer and the flat area is set so as to form a single plane An optical element. The optical element according to claim 1 or 2,
An optical element, wherein the coating material is an inorganic material. The optical element according to claim 1, 2 or 3,
An optical element, wherein the coating layer is formed by applying the coating material in a liquid state using any one of a spin coater, a bar coater, a slit coater, and a flow coater. The optical element according to any one of claims 1 to 4,
An optical element, wherein a microlens array is formed in an optical function area of the optical function element.   The optical functional element used for the structure of the optical element of any one of Claims 1-5.

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