JP7290938B2 - Manufacturing method of cover for infrared detection element - Google Patents

Description

TECHNICAL FIELD The present invention relates to an infrared detection element cover and a method for manufacturing an infrared detection element cover.

Transparent materials such as windows, optical materials, and translucent covers play the role of physically blocking two different environments while transmitting light.

With windows of buildings, even if different environments such as temperature difference, humidity, wind and rain exist between indoors and outdoors, different environments can be maintained by intervening transparent windows, and different environments can occur. Phenomena are visible to each other. In addition, the observation window of the furnace does not allow the heat of the furnace to escape to the outside, and the inside of the furnace can be seen through the window. play an important role. Windows are also used as optical materials such as protective filters that protect optical instruments from sand and dirt. Furthermore, the translucent cover plays a role of protecting the object from dirt, humidity, wind and rain, temperature difference, ultraviolet rays, etc. while transmitting images and color information such as signs, signals, and light receiving elements.

Patent Document 1 discloses a composite material having anti-fogging properties, anti-fouling properties, anti-condensing properties, humidity control properties, drip properties, and cleaning properties that can be applied to mirrors, plate members, lenses, transparent films, etc. , a composition that hygroscopicizes the surface of a member to which they are applied, comprising: (a) at least one selected from zirconyl, zirconium nitrate, zirconium sulfate, and zirconium halide; and (b) a water-absorbing organic polymer and (c) a solvent.

In addition, Patent Document 1 describes that a transparent plate-shaped member that can be coated with the above composition can be used for window glass for houses, glass for furniture, window glass for automobiles, instrument glass for automobiles, and the like. , Eyeglasses, goggles, camera lenses, portable video camera lenses, astronomical telescope lenses, etc. It is described that it can be used as an anti-fogging film attached to a mirror installed in a washroom.

In addition, members that can be coated with the above composition include bathroom ceiling materials, toilet bowl pipes, water supply pipes, urinals, toilet bowls, toilet bowl traps, washbowls, washbasin traps, etc. Bathtubs, bathroom wall materials, bathroom flooring materials, bathroom gratings, shower hooks, bathtub hand grips, bathtub apron parts, bathtub drain plugs, Bathroom windows, bathroom window frames, bathroom window floorboards, bathroom lighting fixtures, drainage perforated plates, drainage pits, bathroom doors, bathroom door frames, bathroom window bars, bathroom door bars, drainboards, mats, soap holders, pails , bathroom mirrors, bath chairs, transfer boards, water heaters, bathroom storage shelves, bathroom handrails, bath lids, bathroom towel racks, shower chairs, washbowl stands, kitchen bags, kitchens floor materials, sinks, kitchen counters, drainage baskets, dish dryers, dishwashers, stoves, range hoods, ventilation fans, stove ignition parts, toilet floor materials, toilet wall materials, toilet ceilings, ball taps, water stopcocks , toilet paper rolls, toilet seats, liftable toilet seats, toilet doors, toilet booth locks, toilet towel racks, toilet lids, toilet handrails, toilet counters, flush valves, tanks, toilet seat nozzles with washing function, etc. Parts, washbasin trap, washroom mirror, washroom storage shelf, drain plug, toothbrush holder, washbasin mirror lighting fixture, washbasin counter, cold soap dispenser, washbowl, oral washer, hand dryer, washing tub, washing machine It is stated that it can be used for lids, washing machine pans, dehydration tanks, air conditioner filters, touch panels, faucet fittings, human body detection sensor covers, shower hoses, shower heads, shower spouts, sealants, and joints.

JP-A-2002-53792

The performance of infrared detection elements such as the above-described human body detection sensors has improved, and improvements in the performance of not only the infrared detection elements but also the peripheral members have come to be demanded.
In the cover of the conventional infrared detection element, the absorption of infrared rays by the material constituting the cover and the coating layer of the cover lowers the sensitivity of the infrared detection element. Therefore, there is a demand for a cover that prevents the SN ratio from deteriorating over a wider range of wavelengths and has a higher transmittance than the cover of the conventional infrared detection element.
In view of the above problems, an object of the present invention is to provide an infrared detection element cover having high transmittance over a wider range of wavelengths and anti-fog properties, and a method for manufacturing the infrared detection element cover.

In order to solve the above problems, the infrared detecting element cover of the present invention has a substrate made of resin and a coating layer made of oxide-based ceramic particles directly bonded to the surface of the substrate, and the coating layer has a thickness of 70 to 300 nm.

According to the cover for the infrared detection element, the coating layer made of oxide ceramics is directly attached to the base material made of resin without using an organic binder. The infrared absorption that the element cover has is only absorption derived from the resin and the oxide-based ceramics. Therefore, it is possible to provide an infrared detection element cover with high sensitivity without the infrared detection element receiving excessive infrared absorption. Moreover, since the formed coating layer is directly bonded to the base material, it becomes a coating layer having a strong bonding force with the base material.

Furthermore, since the coating layer has a thickness of 70 nm or more, it is possible to prevent the substrate from being exposed even if the surface is worn. In addition, since the thickness of the coating layer is set to 300 nm or less, it is difficult for the oxide-based ceramic particles to form a strong bond in the plane direction, and even if stress is applied to the coating layer due to thermal strain, deformation, etc., the deformation follows the deformation. It can be easily expanded and contracted, and cracks are less likely to occur.

In the infrared detecting element cover of the present invention, the oxide-based ceramic particles are desirably silica particles.

The resin constituting the base material is originally water-repellent, and fine water droplets tend to adhere when dew condensation occurs. is formed, the surface becomes hydrophilic and the contact angle of water can be reduced. Therefore, water droplets are less likely to be formed even in a humid environment, and scattering of incident infrared rays can be prevented, thereby exhibiting an excellent anti-fogging effect.

In the infrared detecting element cover of the present invention, the silica particles preferably have a median particle diameter of 1 to 100 nm.

In the infrared detecting element cover of the present invention, since the median particle size of the silica is set to 1 nm or more, a coating layer having a sufficient thickness can be formed, and good wear resistance can be ensured. In addition, since the median particle size of the silica is set to 100 nm or less, the weight per unit surface area of the coating layer can be reduced, and the binding force with the base material made of resin can be sufficiently secured. The coating layer can be made difficult to peel off. In the present invention, the particle size means the diameter of particles, and is a value measured using a dynamic light scattering method. In the present invention, the median particle diameter is the median cumulative number of particles (D-50).

In the infrared detecting element cover of the present invention, it is desirable that the resin constituting the substrate is a single-component resin such as polycarbonate, polymethyl methacrylate, polyethylene or polypropylene.

In the infrared detecting element cover of the present invention, when the resin constituting the base material is a single-component resin made of polycarbonate, polymethyl methacrylate, polyethylene or polypropylene, the number of infrared rays absorbed can be reduced, and infrared rays are emitted. A sufficiently wide band can be secured. In addition, polycarbonate, polymethyl methacrylate, polyethylene and polypropylene have a small number of infrared absorption peaks in the region of 1700 cm ^-1 or more, and together with the coating layer made of oxide ceramic particles, a wide infrared transmission band is secured. can do.

Specifically, in the region of 1700 cm ⁻¹ or more, polycarbonate has a peak around 2900 to 3000 cm ⁻¹ derived from —CH, and polymethyl methacrylate has a peak around 3400 cm ⁻¹ derived from —OH and −CH. A peak around 2900 to 3000 cm ^-1 derived from, polyethylene has a peak around 2800 to 2900 cm ^-1 derived from -CH, and polypropylene has a peak around 2800 to 2900 cm ^-1 derived from -CH, respectively. Yes, it is possible to reduce the influence on the infrared detection element.

In the method of manufacturing the cover for an infrared detection element of the present invention, a base material made of resin is subjected to oxygen plasma treatment, then a dispersion of oxide-based ceramic particles is applied and dried to a thickness of 70 to 300 nm. characterized by forming a coating layer of

In the method for producing a cover for an infrared detection element of the present invention, the surface of a base material is cleaned and the surface of a resin base material, which is hydrophobic, is hydrophilized by applying oxygen plasma treatment. Since the coating layer is formed by applying the dispersion liquid and drying it, the coating layer having a strong binding force to the substrate can be formed.
That is, the resin forming the base material is originally water-repellent (hydrophobic), and fine water droplets tend to adhere when dew condensation occurs. However, in the method of manufacturing the infrared detecting element cover of the present invention, the surface of the water-repellent resin is made hydrophilic by applying oxygen plasma treatment, and then a coating layer of hydrophilic oxide-based ceramic particles is formed. Therefore, the coating layer has a strong binding force to the base material, and the surface of the coating layer is hydrophilic, so that the contact angle of water can be reduced. Therefore, water droplets are less likely to be formed even in a wet environment, and scattering of incident infrared rays can be prevented.

In addition, without forming an organic binder layer on a base material made of resin, a coating layer made of oxide-based ceramic particles is formed directly on the base material surface, and no binder is used. The infrared absorption of the infrared detecting element cover obtained by the production method is only due to the base material made of resin and the oxide-based ceramics. Therefore, the manufactured infrared detection element does not absorb excessive infrared rays, and a method for manufacturing a cover for an infrared detection element with high sensitivity can be provided.

Moreover, since the coating layer is formed with a thickness of 70 nm or more, it is possible to make it difficult for the substrate to be exposed even if the surface is worn. Furthermore, since the coating layer is formed with a thickness of 300 nm or less, it is difficult for the oxide-based ceramic particles to form a strong bond in the plane direction. It is easy to expand and contract following the expansion, and it is possible to make it difficult to form cracks.

In the method of manufacturing the infrared detecting element cover of the present invention, the oxide-based ceramic particles are desirably silica particles.

Silica fine particles having OH groups have infrared absorption at 3700 to 3900 cm ⁻¹ originating from the fundamental vibration of —OH constituting silica. Water also has --OH-derived infrared absorption at 3700 to 3900 cm ⁻¹ , which is the same position as the absorption caused by moisture absorption on the surface. Therefore, by using the manufactured infrared detection element as an infrared detection element for applications that are not easily affected in this frequency band, the effect on the performance can be reduced.

In the method of manufacturing the infrared detecting element cover of the present invention, the silica particles preferably have a median particle size of 1 to 100 nm.

In the method for producing a cover for an infrared detecting element of the present invention, since the median particle size of the silica is set to 1 nm or more, a coating layer having a sufficient thickness can be formed and good abrasion resistance can be secured. be able to. In addition, since the median particle size of the silica is set to 100 nm or less, the weight per unit surface area of the coating layer to be formed can be reduced, and the binding force with the base material made of resin can be sufficiently secured. It is possible to make the coating layer difficult to peel off.

In the method of manufacturing the infrared detecting element cover of the present invention, it is desirable that the resin constituting the substrate is a single component resin such as polycarbonate, polymethyl methacrylate, polyethylene or polypropylene.

In the method of manufacturing the infrared detecting element cover of the present invention, if the resin constituting the substrate is a single-component resin made of polycarbonate, polymethylmethacrylate, polyethylene or polypropylene, the number of infrared rays absorbed can be reduced. , it is possible to secure a wide band through which infrared rays can be sufficiently transmitted. In addition, polycarbonate, polymethyl methacrylate, polyethylene and polypropylene have a small number of infrared absorption peaks in the region of 1700 cm ^-1 or more, and together with the coating layer made of oxide ceramic particles, a wide infrared transmission band is secured. can do.

According to the infrared detecting element cover of the present invention, the oxide-based ceramics are directly bonded to the base material made of resin without the interposition of an organic binder, and no binder is used. The infrared absorption that it has is only absorption derived from resin and oxide ceramics. Therefore, it is possible to provide an infrared detection element cover with high sensitivity without the infrared detection element receiving excessive infrared absorption. Moreover, since the formed coating layer is directly bonded to the base material, it becomes a coating layer having a strong bonding force with the base material.

Further, according to the method of manufacturing the cover for an infrared detecting element of the present invention, the surface of the substrate is activated by the oxygen plasma treatment, and then the ceramic particle dispersion is applied and dried to form the coating layer. It is possible to manufacture an infrared detecting element cover having a coating layer having a strong binding force to the material.
In addition, since a coating layer made of oxide-based ceramic particles is formed on a base material made of resin without an intervening organic binder, and no binder is used, the infrared rays of the manufactured infrared detection element cover The absorption is only due to the base material made of resin and the oxide-based ceramics. Therefore, it is possible to manufacture an infrared detecting element cover with high sensitivity without receiving excess infrared absorption. In addition, since the coating layer is formed after the base material is subjected to the oxygen plasma treatment, the formed coating layer is directly bonded to the base material, and the base material and the coating layer having a strong binding force. Become.

FIGS. 1(a) to 1(d) are process diagrams showing the manufacturing process of the infrared detecting element cover of the present invention.

(Detailed description of the invention)
The infrared detecting element cover of the present invention has a substrate made of a resin and a coating layer made of oxide-based ceramic particles bonded directly to the surface of the substrate, and the thickness of the coating layer is 70 to 70. It is characterized by being 300 nm.

The infrared detecting element for which the cover for an infrared detecting element of the present invention is used may be either a thermal type or ^a quantum type, and the type thereof is not particularly limited. Those having sensitivity in the near infrared (0.7-2.5 μm) to mid-infrared (2.5-4 μm) are preferable.

Applications of infrared detection elements include radiation thermometers, HMDs (hot melt detectors), flame monitors, moisture meters, gas analyzers, spectrophotometers, film thickness meters, laser monitors, optical power meters, laser diodes, O/E Transducers, FTIR, infrared imagers, remote sensing, human body detectors, and the like.

Types of thermal infrared detection elements include thermocouples, thermopiles, bolometers, Golay cells, pyroelectric elements, etc. PZT, TGS, _LiTaO3 , etc. can be used as detectors for pyroelectric elements.

Quantum type infrared detection elements are classified into intrinsic type detection elements and impurity type detection elements, and either element may be used. PbS, PbSe, InSb, HgCdTe, Ge, InGaAs, InAs, InSb, or the like can be used as a detector that constitutes the intrinsic detection element. Ge:Au, Ge:Hg, Ge:Cu, Ge:Zn, Si:Ga, Si:As, etc. can be used as detectors constituting the impurity-type detection element. Among them, PbS, PbSe, Ge, InGaAs, and the like, which are hardly affected by dark current caused by thermoelectrons inside the element and can be used at room temperature, can be preferably used.

In addition, the infrared detection element cover of the present invention can also be used for a visible light imaging element using silicon. An image sensor for visible light is usually sensitive to the infrared region, so an infrared cut filter is used to block infrared rays from reaching the image so that the infrared rays do not disturb the color balance. Even if it is an imaging device for visible light, the cover for an infrared detection device of the present invention can be used for devices that do not use an infrared cut filter or that use a bandpass filter in the infrared region.

The resin used for the substrate constituting the infrared detecting element cover of the present invention is not particularly limited as long as it is a material that transmits infrared rays. Examples of resin types include polycarbonate, polymethyl methacrylate, polyethylene, and polypropylene. These resins have few infrared absorption peaks derived from chemical bonds that reduce the sensitivity of the infrared detection element in the short wavelength region of 1700 cm ^-1 or more, and when used as a cover for the infrared detection element, infrared detection with high sensitivity and high reliability. element can be obtained. Polycarbonate and polymethyl methacrylate have mechanical strength and high visible light transmittance, so that they can be used as windows for visible light as well as infrared rays. Furthermore, since polyethylene and polypropylene consist only of hydrogen and carbon and do not have double bonds, the infrared absorption peak is small and the influence of the base resin can be reduced.

In the infrared detecting element cover of the present invention, the coating layer has a thickness of 70 to 300 nm.

In the infrared detecting element cover of the present invention, since the coating layer has a thickness of 70 to 300 nm, it is possible to prevent the substrate from being exposed even if the surface is worn. In addition, it is difficult for the oxide-based ceramic particles to form a strong bond in the plane direction, and even if stress is applied to the coating layer due to thermal strain or deformation, it is easy to expand and contract along with the deformation, and cracks are difficult to form. can do.

When the thickness of the coating layer is less than 70 nm, the thickness of the coating layer is too thin, so that the base material is likely to be exposed when the surface is worn, and the effect of forming the coating layer may be difficult to produce. . On the other hand, when the thickness of the coating layer exceeds 300 nm, the oxide-based ceramic particles tend to form strong bonds in the plane direction, and when stress is applied to the coating layer, cracks and the like may easily occur.

The infrared detecting element cover of the present invention has a coating layer composed of oxide-based ceramic particles directly bonded to the surface of the substrate, and does not have a binder layer between the coating layer and the substrate. Therefore, it is possible to minimize infrared absorption of the infrared detecting element cover.
Ceramics constituting the oxide-based ceramic particles include, for example, silica, alumina, titania, and the like.

In the infrared detecting element cover of the present invention, the oxide-based ceramic particles are desirably silica particles.

The resin constituting the base material is originally water-repellent, and fine water droplets tend to adhere when dew condensation occurs. is formed, the surface becomes hydrophilic and the contact angle of water can be reduced. Therefore, water droplets are less likely to be formed even in a humid environment, and scattering of incident infrared rays can be prevented, thereby exhibiting an excellent anti-fogging effect.

In the infrared detecting element cover of the present invention, when the oxide-based ceramic particles are silica particles, the silica has infrared absorption at 3700 to 3900 cm ⁻¹ derived from the fundamental vibration of —OH constituting silica. However, water also has --OH-derived infrared absorption at 3700 to 3900 cm ⁻¹ , which is the same position as the absorption of water caused by moisture absorption on the surface. Therefore, by using the infrared detecting element of the present invention as an infrared detecting element for applications that are not easily affected in this frequency band, the infrared detecting element can be highly reliable.

In the infrared detecting element cover of the present invention, the silica preferably has a median particle size of 1 to 100 nm.

In the infrared detecting element cover of the present invention, since the median particle size of the silica is 1 to 100 nm, a coating layer having a sufficient thickness can be formed, and good abrasion resistance can be secured. Also, the weight per unit surface area of the coating layer can be reduced, the binding force to the base material made of resin can be sufficiently ensured, and the coating layer can be made difficult to peel off.

It is technically difficult to make the median particle size of the silica less than 1 nm, and it tends to aggregate and form secondary particles, so it may be difficult to form a coating layer with a uniform thickness. be. On the other hand, when the median particle size of the silica exceeds 100 nm, the number of silica particles that bind per unit area decreases, making it difficult to ensure sufficient binding force with the base material made of resin. Sometimes.

Next, a method for manufacturing the infrared detecting element cover of the present invention will be described.
In the method of manufacturing the infrared detecting element cover of the present invention, a base material made of resin is subjected to oxygen plasma treatment, then a dispersion of oxide-based ceramic particles is applied and dried to obtain a thickness of 70 to 300 nm. characterized by forming a coating layer of

FIGS. 1(a) to 1(d) are process diagrams showing the manufacturing process of the infrared detecting element cover of the present invention.
(1) Preparatory Step In the method of manufacturing the infrared detecting element cover of the present invention, first, as a preparatory step, a substrate 11 made of resin is prepared (see FIG. 1(a)).

As the resin constituting the base material 11, the resin such as the polycarbonate described in the cover for the infrared detecting element of the present invention is used.
The shape of the base material 11 is not particularly limited. In FIG. 1(a), the base material 11 is plate-like, but the part forming the coating layer may have a curved surface.

(2) Plasma treatment step In the method of manufacturing the infrared detection element cover of the present invention, next, as the plasma treatment step, the substrate 11 made of resin is subjected to oxygen plasma treatment by the oxygen plasma treatment device 21 (Fig. 1(b)). )reference).
The oxygen plasma treatment is an operation in which a high voltage is generated in the presence of oxygen, and the generated oxygen radicals, ozone, and the like attack the surface of the object.
Electrons emitted from the electrode at high voltage are accelerated in the electric field, collide with electrons and molecules in the atmosphere, and ionize or excite the molecules. Electrons are also emitted from the ionized molecules, electrons are generated repeatedly, and a plasma state is created.

In this plasma treatment process, electrons generated from the electrodes and electrons generated by ionization reach the surface of the resin sandwiched between the high voltage electrodes, cleaning the surface and is cleaved to produce reactive end groups 13 with active radicals. Since active oxygen radicals and ozone are also present in the atmosphere, they can be combined with each other to form a hydrophilic layer on the very thin surface layer (see FIG. 1(c)).
As the plasma apparatus, in addition to a processing apparatus using microwaves, a flame processing apparatus that performs processing in a flame at atmospheric pressure can also be used. Conditions for the plasma treatment using microwaves are appropriately selected according to the size, the number of treatments, and the material of the cover for the infrared detection element. For example, when treating a 100 cm ² infrared detection element cover with a treatment apparatus using microwaves, the output is 50 to 2000 W, the oxygen flow rate is 0.1 to 1000 ml/min, the pressure is 1 Pa to atmospheric pressure, and the treatment time is 1 to 600. Processing can be applied in the range of seconds.

(3) Coating step In the method of manufacturing the infrared detecting element cover of the present invention, after the plasma treatment step, as the coating step, a dispersion of oxide-based ceramic particles is applied to form a coating layer.
Specifically, fine oxide-based ceramic particles are dispersed in a solvent to prepare a coating liquid, and the coating liquid is applied to the surface of the substrate. It is desirable that the coating step be performed as early as possible after the plasma treatment step. This is because the hydrophilic layer formed by the plasma treatment is oxidized to become a hydrophobic layer over time. Desirably, after the plasma treatment step, the time to apply the coating liquid is within 12 hours.

As described above, the oxide-based ceramic particles are preferably silica particles, and the median particle size thereof is preferably 1 to 100 nm.
Examples of the solvent include water, alcohols such as methanol, ethanol and propanol, glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, and PGM (propylene glycol monomethyl ether).
Silica particles having hydrophilicity include, for example, nano silica particles Admanano manufactured by Admatechs, organosilica sol MA-ST manufactured by Nissan Chemical Co., Ltd., IPL-ST, EG-ST, NPC-ST, PGM-ST, DMAC-ST, ASW-30, BW-30, etc. manufactured by Japan Nanocoat Co., Ltd. can be used.

The concentration of the oxide-based ceramic particles in the dispersion liquid is desirably 0.1 to 5.0% by weight when silica particles are used as the oxide-based ceramic particles.
Generally, fine silica particles are provided in a dispersion state so as not to solidify. Therefore, by further diluting the silica particle dispersion with a solvent, it is possible to obtain a dispersion having the desired content ratio.
The method of applying the dispersion of oxide-based ceramic particles to the substrate surface is not particularly limited, and includes a coating film forming method using a bar coater, an applicator, etc., a dip coating method, and a spin coating method. The application method can be appropriately selected depending on the shape of the infrared detection element cover and the like. For a flat plate, a spin coating method is desirable.
Spin coating is a method in which a solution or suspension is dropped onto the center of a base material rotating at high speed, and a thin coating layer is formed on the surface of the base material while centrifugal force removes excess liquid. Volatilization of the solution or suspension during or after the formation of the coating layer can form a very thin coating layer on the surface of the substrate. In addition, since excess liquid is removed in the spin coating method, there is no correlation between the amount of liquid supplied and the thickness of the coating layer. The thickness can be adjusted by the number of times of spin coating.

(4) Drying Step In the method of manufacturing the infrared detecting element cover of the present invention, after the coating step, the coated layer is dried to form the coating layer 12 (FIG. 1(d)) as a drying step.
As drying conditions, the drying temperature is preferably 80 to 140° C., and the drying time is preferably 3 minutes to 3 hours.

It is believed that the surface of the base material made hydrophilic by the plasma treatment and the coating layer made of oxide-based ceramic particles, particularly silica particles, are firmly bound together by hydrogen bonding. For this reason, a coating layer having durability and being difficult to peel off is formed on the surface of the resin, and the antifogging property can be maintained for a long period of time.

The thickness of the coating layer formed on the substrate surface is 70 to 300 nm.
Since it is an object of the present invention to manufacture an infrared detecting element cover having an anti-fogging effect by forming the coating layer, the coating layer is usually formed on one main surface of the substrate 11. Coating layers may be formed on both main surfaces depending on the application.

(Examples 1 to 4 and Comparative Examples 1 to 3)
(1) Preparatory step As a base material, a base material made of polycarbonate was prepared. The substrate is a flat plate of 90 mm x 90 mm x 5 mm. After washing this substrate with isopropyl alcohol, it was washed again with pure water.

(2) Plasma treatment process Using a plasma treatment apparatus EXAM (E1124-S25) using microwaves manufactured by Shinko Seiki Co., Ltd., the surface of the substrate was subjected to oxygen plasma treatment. The oxygen plasma treatment was performed under the following conditions, changing only the treatment time.
The conditions for the oxygen plasma treatment were an output of 500 W, an oxygen flow rate of 100 ml/min, and a pressure of 20 Pa, and the oxygen plasma treatment time was varied from no treatment (0 seconds), 20 seconds, 40 seconds, and 80 seconds.

(3) Coating step and drying step In the coating step, silica particle dispersions of Dispersions 1 to 3 having compositions shown in Table 1 below are used to form a coating layer on the surface of the substrate by spin coating, A coating layer was formed by drying at 120° C. for 1 hour. Silica particles were prepared by diluting ASW-30 manufactured by Japan Nanocoat Co., Ltd. with a solvent and adjusting the concentration of each dispersion liquid shown in Table 1. Table 2 below shows the plasma treatment time, the number of rotations of spin coating, and the thickness of the formed coating layer in each example and comparative example.
In the present examples and comparative examples, the composition shown in Table 1 was used, the rotation speed of spin coating was changed to form a relatively thin coating layer, the surface was visually observed, and the uniformity and the presence or absence of cracks were checked. evaluated. The evaluation results are shown in Table 2. The thickness of the coating layer was obtained by previously forming a portion without the coating layer using a mask and measuring the difference in level from the portion without the coating layer using a laser microscope.

(Examples 5-10 and Comparative Examples 4-9)
In this example and comparative example, the preparation step, plasma treatment step, coating step and drying step were performed in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3 to form a coating layer. In this example and comparative example, a thicker coating layer was formed than in Examples 1-4 and Comparative Examples 1-3.

When it was found that cracks did not occur in the obtained coating layer, the peelability was evaluated by the following test. Table 3 shows the evaluation results.

(Peelability evaluation test)
First, grid-like streaks are formed on the coating layer with a cutter knife. 11 streaks are formed in the vertical and horizontal directions with an interval of 1 mm between the respective streaks. The number of squares forming the lattice is 100 pieces.
A pressure-sensitive adhesive tape was attached to the grid formed, peeled upward, and the number of squares where peeling occurred was counted to evaluate the peelability. In the evaluation results of peelability of the coating layer in the table, the numerator is the number of squares where peeling occurred, and the denominator is the total number of squares (100 pieces). The smaller the number of molecules, the more difficult the coating layer is to peel off.

As is clear from the results in Tables 2 and 3 above, those not subjected to plasma treatment lacked uniformity, cracked, and had insufficient adhesion to the substrate, showing good properties. It was found that no coating layer was formed.
In addition, among those subjected to plasma treatment, when the thickness of the coating layer is 70 nm or more and 300 nm or less, the silica particles are uniformly dispersed on the surface to obtain an even coating layer, and strong adhesion to the substrate. was found to be obtained.

11 Base material 12 Coating layer 13 Reactive end group 21 Plasma treatment device

Claims (4)

A base material made of a resin is subjected to an oxygen plasma treatment, then a dispersion of oxide ceramic particles is applied and dried to form a coating layer having a thickness of 70 to 300 nm and consisting only of the oxide ceramic particles. A method for manufacturing an infrared detection element cover, characterized by forming a. 2. The method of manufacturing a cover for an infrared detecting element according to claim 1 , wherein said oxide-based ceramic particles are silica particles. 3. The method for manufacturing an infrared detecting element cover according to claim 2 , wherein the silica particles have a median particle size of 1 to 100 nm. The infrared detecting element cover according to any one of claims 1 to 3 , wherein the resin constituting the base material is a single component resin made of polycarbonate, polymethyl methacrylate, polyethylene or polypropylene. manufacturing method.

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