JP2006267160A - Manufacturing method of microlens and microlens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microlens improved in a light condensing ratio by simple system constitution, and also to provide its manufacturing method. <P>SOLUTION: The manufacturing method of the microlens has: a first microprojection forming step of forming first microprojections 4b of a convex shape by making droplets 4a of a light transmissive resin adhere onto a light transmissive substrate 1 at fixed intervals and then hardening them; and a second microprojection forming step of forming second microprojections 6b of a concave shape by making droplets 6a of the light transmissive resin drop and adhere onto the substrate 1 between the first microprojections 4b so as to fill up between the first microprojections 4b and then hardening them. The second microprojection 6b has lower height than that of the first microprojection 4b and is formed to a recessed shape where a peripheral part stands up toward a central part along the protruded shape of the first microprojection 4b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microlens manufacturing method and a microlens. Specifically, the present invention relates to a method for manufacturing a microlens by an inkjet method and a microlens.

In recent years, an optical element called a microlens in which a large number of microlenses are arranged has been provided. Such an optical element is, for example, an element that is formed on the screen surface of a liquid crystal projector system to brighten an image, an optical fiber optical interconnection or a laser condensing element, and a CCD or CMOS. Is used as a condensing element for collecting incident light in an image sensor of a digital still camera.
Conventionally, the following method is known as a method of manufacturing a microlens.

<Wet process method>
As shown in FIG. 7, (a) αSi12a is coated on substrate 11 → (b) αSi12a is crystallized to pSi12b by heat treatment → (c) Photoresist 13 is coated on pSi12b → (d) Initial hole 14 is exposed Development → (e) Etching → (f) Resist stripping → (g) Etching with hydrofluoric acid → (h) Laminating cover glass 16 with adhesive 15 to form a lens (concave lens).

<Dry process method>
As shown in FIG. 8, (a) coating the photoresist 22 on the substrate 21 → (b) exposing and developing the initial hole 23 → (c) reflowing by heat treatment (rounding the corners of the initial hole 23) → (d) Dry etching with plasma → (e) Resist removal → (f) A cover glass 26 is bonded with an adhesive 25 to form a lens (convex lens).

<Inkjet method>
As shown in FIG. 9, (a) water repellent treatment (formation of a water repellent layer 32) on the substrate 31 → (b) droplets 34a of light transmitting resin are discharged and dropped from a droplet discharge head (inkjet head) 33. Then, the fine protrusions 34b are formed on the substrate 31 at regular intervals. → (c) The fine protrusions 34b on the substrate 31 are cured. → (d) A cover glass 37 is bonded with an adhesive 36 to form a lens (see Patent Document 1). .

JP 2003-240911 A

<Wet process method and dry process method>
This is a process equivalent to semiconductor manufacturing and requires a large-scale apparatus, which is expensive.

<Inkjet method>
Since it can be configured easily in terms of equipment, it is advantageous in terms of cost, but since it cannot be brought into contact with the next lens, the filling rate cannot be increased, and the above wet process method in terms of transmittance and light collection rate And inferior to dry process method.

  An object of the present invention is to provide a microlens manufacturing method and a microlens that can improve the light collection rate with a simple apparatus configuration.

The method for manufacturing a microlens according to the present invention is a method for manufacturing a microlens composed of convex first fine protrusions and concave second fine protrusions, and transmits light onto a light-transmitting substrate. A first fine protrusion forming step of forming a first fine protrusion by dropping and adhering a liquid crystalline resin droplet at regular intervals and curing the first fine protrusion; and filling the space between the first fine protrusions And a second fine protrusion forming step of forming a second fine protrusion by dropping and adhering a light-transmitting resin droplet onto the substrate in between.
Here, the fine protrusion indicates a protrusion formed upward from the surface of the substrate regardless of the uneven shape. Further, the amount of the light-transmitting resin droplet in the second fine protrusion forming step is that the height of the second fine protrusion is lower than the height of the first fine protrusion. The amount is defined such that the dropped droplets for forming the second fine protrusions do not come into contact with the adjacent droplets for forming the second fine protrusions. In this case, since it depends on the surface tension on the substrate and the viscosity of the droplets, the amount of droplets for forming the second fine protrusions is defined in consideration of these factors.

In this configuration, when the light-transmitting resin droplets are attached to the light-transmitting substrate at regular intervals and cured in the first fine protrusion forming step, the convex first fine protrusions are constant. Formed at intervals.
After that, in the second fine protrusion forming step, a droplet of light-transmitting resin is attached between the first fine protrusions to form second fine protrusions that fill the space between the first fine protrusions. At this time, the droplet amount of the light-transmitting resin in the second fine protrusion forming step is defined so that the height of the second fine protrusion is lower than the height of the first fine protrusion. Then, the light-transmitting resin droplets adhered between the first fine protrusions have a shape in which the peripheral part in contact with the first fine protrusions rises along the convex shape of the first fine protrusions with respect to the central part. In this state, it is cured.

According to the method of manufacturing a microlens of the present invention, after forming a first fine protrusion on a light-transmitting substrate by depositing a light-transmitting resin droplet, the light-transmitting property is provided between the first fine protrusions. Since it is only necessary to form the second fine protrusions by attaching the resin droplets, that is, if the liquid droplet discharging mechanism capable of discharging the light-transmitting resin droplets is provided, the first and second fine protrusions are formed. Since it can be formed, it can be configured with a simpler device and can be made cheaper than the conventional wet process method and dry process method.
Moreover, according to the microlens manufactured through such a process, since the concave second fine protrusions are formed between the convex first fine protrusions formed at regular intervals, In addition to the light condensing effect of the convex first microprotrusions, the adjacent concave second microprotrusions can exhibit the light condensing effect as a concave lens, so that the light condensing efficiency can be improved as compared with the conventional ink jet method. it can.

In the method for manufacturing a microlens of the present invention, in the first fine protrusion forming step, the first fine protrusion is formed in a lattice shape on the substrate, and in the second fine protrusion forming step, the first fine protrusion is formed in a lattice shape. A droplet of light-transmitting resin is dropped on the center surrounded by the four adjacent first fine protrusions so as to adhere to all the four first fine protrusions, and the second fine protrusions are moved to the four first fine protrusions. It is preferable to form in a space surrounded by one fine protrusion.
Here, the droplet discharge head may discharge one droplet, or may discharge two or more droplets simultaneously.
With such a configuration, the first fine protrusions and the second fine protrusions and the second fine protrusions can be obtained only by ejecting and dropping the light-transmitting resin droplets from the droplet ejection head every time the droplet ejection head moves while moving the droplet ejection head. Since the fine protrusions can be formed, the first fine protrusions and the second fine protrusions can be accurately formed at regular intervals with a simple apparatus configuration.
Moreover, in the second fine protrusion forming step, a light-transmitting resin droplet is discharged from the droplet discharge head to the center surrounded by the four first fine protrusions formed in a lattice shape in the first fine protrusion forming step. Since it only has to be dripped, the intermittent feed control of the droplet discharge head can be performed very easily.

In the microlens manufacturing method of the present invention, it is preferable that after the first fine protrusion forming step, a hydrophilic treatment step for hydrophilizing the surface of the first fine protrusion is performed, and then the second fine protrusion forming step is performed. .
According to this configuration, when the surface of the first fine protrusion is made hydrophilic, the light-transmitting resin dropped in the second fine protrusion forming step adheres to the surface of the first fine protrusion. Since the surface tension of the liquid droplets can be reduced, the light-transmitting resin droplets are pulled on the surface of the hydrophilic first fine protrusions, so that the concave second fine protrusions are more effective. Can be formed.

The microlens of the present invention fills a space between the first fine protrusions, a substrate having light permeability, convex first fine protrusions made of a light-transmitting resin formed on the substrate at regular intervals. And a concave second fine protrusion formed of a light-transmitting resin.
According to such a configuration, the first fine protrusions are formed at regular intervals on the light-transmitting substrate, and the second fine protrusions are formed between the first fine protrusions. The height from the first fine protrusion is lower than that of the first fine protrusion, and the peripheral portion in contact with the first fine protrusion is raised along the convex shape of the first fine protrusion with respect to the surface shape of the central portion of the second fine protrusion. Since it is formed, a microlens having a concave second fine protrusion formed between the convex first fine protrusions is obtained.
Therefore, in addition to the light condensing effect of the convex first fine protrusions, the adjacent concave second fine protrusions can exhibit the light condensing effect as a concave lens, so that the light condensing efficiency is improved as compared with the conventional inkjet method. be able to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Description of the manufacturing method of the microlens of this embodiment>
FIG. 1 shows a method for manufacturing the microlens of this embodiment.
The manufacturing method of the microlens of this embodiment includes (a) water-repellent treatment of the substrate, (b) first fine protrusion attaching step, (c) first fine protrusion curing step, (d) hydrophilic treatment step, (e) A second fine protrusion attaching step, (f) a second fine protrusion hardening step, and (g) a bonding step.
Here, the first fine protrusion forming step is constituted by (b) the first fine protrusion attaching step and (c) the first fine protrusion hardening step. Further, the second fine protrusion forming step is constituted by (e) the second fine protrusion attaching step and (f) the second fine protrusion hardening step.

(A) Water repellent treatment of substrate The surface of the substrate 1 is subjected to water repellent treatment. That is, by forming the water repellent layer 2 on the surface of the substrate 1, the surface of the substrate 1 is controlled to a desired surface tension and interface tension.
As the substrate 1, when the obtained microlens is applied to an optical film for a screen, for example, a cellulose resin such as cellulose acetate or propylcellulose, a transparent resin such as polyvinyl chloride, polyethylene, polypropylene, or polyester (light-transmitting property) A light transmissive sheet made of resin) or a light transmissive film is used. When the microlens is applied to a microlens array or the like, the substrate 1 is made of a transparent material (light transmissive material) such as glass, polycarbonate, polyarylate, polyethersulfone, amorphous polyolefin, polyethylene terephthalate, or polymethyl methacrylate. It is also possible to use a substrate made of

As the water repellent treatment, for example, a method by plasma polymerization can be used. In this treatment, a raw material liquid for water repellent treatment is prepared. As the raw material liquid, a liquid organic material composed of linear PFC such as C ₄ F ₁₀ or C ₈ F ₁₆ is preferably used. After preparing such a raw material liquid, this vapor is converted into plasma in a plasma processing apparatus. Then, since the vapor | steam of this linear PFC was made into plasma, a part of coupling | bonding of linear PFC is cut | disconnected and activated. When a part of the bond is cut in this way and the activated PFC reaches the surface of the substrate 1, these PFCs are polymerized with each other on the substrate 1 to form a fluororesin polymer film having water repellency.
In addition, as a raw material liquid for water repellent treatment, for example, decatriene can also be used. In that case, by adding CF ₄ or oxygen activated by plasma treatment, water repellency can be imparted to the resulting polymer film, whereby a water-repellent polymer film can be formed. Moreover, fluorocarbon can also be used as a raw material liquid for water repellent treatment. In that case, by adding CF ₄ activated by the plasma, even if a part of the fluorine in the fluorocarbon which is the raw material liquid is released by the plasma, the active fluorine is taken into the polymer film to be obtained. The water repellency of the fluororesin polymer film to be formed can be increased.

(B) First fine protrusion attaching step While moving the droplet discharge head 3, the droplet 4a of light-transmitting resin is discharged and dropped from the droplet discharge head 3 every time the droplet discharge head 3 moves, and is attached onto the substrate 1. .
As the droplet discharge head 3, a nozzle plate and a diaphragm are joined via a partition member, and a liquid material of light transmissive resin is stored in a space partitioned by the partition member, and this liquid material is used as a nozzle. The thing of the structure made to discharge and drip from the nozzle hole formed in the plate can be utilized. Alternatively, as a method other than the piezo jet type, a method using an electrothermal converter as an energy generating element, or an electric field drive for discharging a droplet by electrostatic attraction between electrodes disclosed in Japanese Patent Laid-Open No. 8-132608 The mold method can be adopted.

Examples of the light transmissive resin include acrylic resins such as polymethyl methacrylate, polyhydroxyethyl methacrylate, and polycyclohexyl methacrylate, allyl resins such as polydiethylene glycol bisallyl carbonate and polycarbonate, methacrylic resins, polyurethane resins, polyester resins, and polyresins. Thermoplastic or thermosetting resins such as vinyl chloride resins, polyvinyl acetate resins, cellulose resins, polyamide resins, fluorine resins, polypropylene resins, polystyrene resins, etc., are included. Used, or a mixture of a plurality of species.
In the present embodiment, a radiation curable resin is used as the light transmissive resin. The radiation irradiation curable type is obtained by blending a light-transmitting resin with a photopolymerization initiator such as a biimidazole compound, thereby imparting radiation irradiation curability. Radiation is a general term for visible rays, ultraviolet rays, far ultraviolet rays, X-rays, electron beams, and the like, and in particular, ultraviolet rays are generally used.

As shown in FIG. 2 (a), radiation-irradiation-curable light-transmitting resin droplets 4 a are ejected and dropped from the droplet ejection head 3 and adhered onto the substrate 1. Then, the light-transmitting resin droplets 4a discharged and dropped from the droplet discharge head 3 become convex (substantially hemispherical) fine protrusions 4b (first fine protrusions) on the substrate 1 due to the surface tension thereof. At this time, since the surface of the substrate 1 is subjected to water repellent treatment, the first fine protrusion 4b having a large contact angle between the substrate 1 and the droplet 4a, that is, a high height is obtained. The contact angle can also be increased by increasing the viscosity of the droplet 4a.
As shown in FIG. 2 (b), while moving the droplet discharge head 3, a light-transmitting resin droplet 4 a is discharged from the droplet discharge head 3 and adhered onto the substrate 1 every time the droplet discharge head 3 moves. As a result, the first fine protrusions 4b are formed in a lattice shape (vertical and horizontal lattice shape).

(C) First fine protrusion curing step After the first fine protrusions 4b are formed on the substrate 1 in the form of a lattice by applying the light-transmitting resin droplets 4a, the first fine protrusions 4b are irradiated with radiation 5. And cure. Here, ultraviolet rays are irradiated. When a thermosetting light transmissive resin is used as the first fine protrusion forming material, the light transmissive resin is cured by heat treatment (about 100 ° C. heat treatment).

(D) Hydrophilic treatment process The surface of the 1st fine protrusion 4b hardened | cured at the 1st fine protrusion hardening process, ie, the light-transmitting resin surface, is plasma-treated, and a hydrophilic treatment is performed.

(E) Second fine protrusion attaching step While moving the droplet discharge head 3, the light-transmitting resin droplet 6a is attached between the first fine protrusions 4b so as to fill the space between the first fine protrusions 4b.
About the droplet discharge head 3 and light transmissive resin, the same thing as the droplet discharge head 3 and light transmissive resin used at the 1st fine protrusion adhesion process is used. More preferably, use is made of a light-transmitting resin used in the first fine protrusion attaching step to which a surfactant is added. The amount of the surfactant contained in the light transmissive resin is preferably 10 to 500 ppm with respect to the light transmissive resin.

As shown in FIG. 3A, a droplet 6a of a radiation curable curable resin is discharged from the droplet discharge head 3 and dropped between the first fine protrusions 4b. Then, the light-transmitting resin droplet 6a dropped from the droplet discharge head 3 between the first fine protrusions 4b is filled in the space surrounded by the four first fine protrusions 4b, and between the first fine protrusions 4b. The second fine protrusion 6b is embedded. At this time, the droplet amount of the light-transmitting resin is such that the height of the second fine protrusion 6b from the substrate 1 is lower than the maximum height of the first fine protrusion 4b from the substrate 1, and The amount is defined such that the droplet 6a for forming the second fine protrusion dropped between the one fine protrusion 4b does not contact the adjacent droplet 6a for forming the second fine protrusion. As a result, the second fine protrusion 6b has a shape in which the peripheral portion in contact with the first fine protrusion 4b rises along the convex shape of the first fine protrusion 4b with respect to the central portion.
As shown in FIG. 3B, the droplet discharge head 3 is moved at the center surrounded by the four first fine projections formed in a lattice shape in the first fine projection forming step while moving the droplet discharge head 3. When the light-transmitting resin droplet 6a is dropped from 3, the second fine protrusion 6b filling the space surrounded by the four first fine protrusions 4b is formed. That is, in the space surrounded by the four first fine protrusions 4b, the concave second fine protrusions 6b in contact with all the four first fine protrusions 4b are formed.

(F) Second fine protrusion curing step After forming the second fine protrusions 6b between the first fine protrusions 4b by applying the light-transmitting resin droplet 6a, the second fine protrusions 6b are irradiated with the radiation 5. And cure. Here, ultraviolet rays are irradiated. When a thermosetting light transmissive resin is used as the first fine protrusion forming material, the light transmissive resin is cured by heat treatment (about 100 ° C. heat treatment).

(G) Laminating Step A microlens 9 is manufactured by laminating a cover glass 8 with an adhesive 7 on the substrate 1 on which the first fine protrusions 4b and the second fine protrusions 6b are formed.

<Description of Microlens of First Embodiment>
4 is an enlarged plan view of a part of the microlens 9 manufactured through the above-described steps, and FIG. 5 is a cross-sectional view taken along the line V-V in FIG.
The microlens 9 according to the present embodiment includes a plurality of convex first substrates made of a light-transmitting substrate 1 and a light-transmitting resin formed on the substrate 1 in a grid pattern (vertical and horizontal grid pattern) at regular intervals. Protrusions 4b and a plurality of concave second microprotrusions 6b made of light-transmitting resin formed between the four first microprotrusions 4b and filled between the first microprotrusions 4b. Yes.
The second fine protrusion 6b has a height lower than that of the first fine protrusion 4b, and a shape in which a peripheral portion in contact with the first fine protrusion 4b rises along the convex shape of the first fine protrusion 4b with respect to the central portion ( (Concave shape).

That is, the first fine protrusions 4b are formed in a lattice pattern on the light-transmitting substrate 1, and the second fine protrusions 6b are formed in the space surrounded by the first fine protrusions 4b. Since the height is lower than the first fine protrusion 4b, and the peripheral portion in contact with the first fine protrusion 4b is formed so as to rise along the convex shape of the first fine protrusion 4b with respect to the central portion. A microlens having a concave second fine protrusion 6b formed between the convex first fine protrusions 4b is obtained.
Therefore, as shown in FIG. 6, in addition to the light condensing effect of the convex first fine protrusions 4b, the adjacent concave second fine protrusions 6b can exert a light condensing effect as a concave lens, so that the conventional ink jet method is used. In comparison, the light collection efficiency can be improved.

<Description of modification>
In the above embodiment, the first fine protrusions 4b are formed in a plurality of rows, but the first fine protrusions 4b may be in a single row.
In the above embodiment, the light-transmitting resin that forms the first fine protrusions 4b and the light-transmitting resin that forms the second fine protrusions 6b are made of the same material. A permeable resin may be used.

  The microlens of the present invention is an element that is formed on the screen surface of a liquid crystal projector system to brighten an image, an optical fiber optical interconnection, a laser condensing element, or a digital still such as a CCD or CMOS. It can be used as a condensing element that collects incident light in an imaging element of a camera.

Process drawing which shows the manufacturing method of the micro lens which concerns on embodiment of this invention. The figure which shows the 1st fine protrusion adhesion process in embodiment same as the above. The figure which shows the 2nd fine protrusion adhesion process in embodiment same as the above. The elements on larger scale of the microlens in embodiment same as the above. VV sectional view taken on the line of FIG. The fragmentary sectional view of the micro lens in an embodiment same as the above. The figure which shows the conventional wet process system. The figure which shows the conventional dry process system. The figure which shows the conventional inkjet system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Water-repellent layer, 3 ... Droplet discharge head, 4a ... Droplet, 4b ... First fine protrusion, 5 ... Radiation, 6a ... Droplet, 6b ... Second fine protrusion, 7 ... Adhesive, 8 ... cover glass, 9 ... micro lens.

Claims (4)

A method of manufacturing a microlens composed of convex first fine protrusions and concave second fine protrusions,
A first fine protrusion forming step of forming droplets of a light transmissive resin at regular intervals on a substrate having light permeability and curing to form the first fine protrusion;
A second micro-projection is formed by dropping a light-transmitting resin droplet onto the substrate between the first micro-protrusions so as to fill the space between the first micro-protrusions and curing the droplets. A method of manufacturing a microlens, comprising: a protrusion forming step. In the manufacturing method of the micro lens of Claim 1,
In the first fine protrusion forming step, the first fine protrusions are formed in a lattice shape on the substrate,
In the second fine protrusion forming step, all of the four first fine protrusions are formed on the central substrate surrounded by the four adjacent first fine protrusions formed in a lattice shape. A microlens manufacturing method, wherein the second microprotrusions are formed in a space surrounded by the four first microprotrusions by dropping them so as to adhere to the surface. In the manufacturing method of the micro lens of Claim 1 or 2,
A method of manufacturing a microlens, wherein after the first fine protrusion forming step, a hydrophilic treatment step for hydrophilizing the surface of the first fine protrusion is performed, and then the second fine protrusion forming step is performed. A substrate having optical transparency;
Convex-shaped first fine protrusions made of a light-transmitting resin formed on the substrate at regular intervals,
A microlens comprising a concave second fine protrusion made of a light-transmitting resin and formed so as to fill a space between the first fine protrusions.

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