JP7356184B2 - Manufacturing method of light absorber - Google Patents

Description

The present invention relates to a light absorber made of a photosensitive material.

Devices that use light to obtain information sometimes require light absorbers to adjust the amount of light and optical path, and to remove reflected light that causes ghosts and flares. This film is produced by physical and chemical methods such as vapor deposition or painting on glass or plastic materials. Particularly in medical and eyeglass equipment-related applications, optical elements are formed that absorb and remove harmful reflected light and scattered light, which are called sunspots, black spots, and speckles, and occur in the cornea and crystalline lens of the eye (for example, Patent Document (see 1).

Specifically, we use photolithography technology to pattern a chromium film on a glass plate to form regular protrusions that function as scales, encoders, diffraction elements, etc., or we drill holes and fill them with black paint. It was formed.

Special Publication No. 62-30767

However, the formed protrusions tend to bulge in an elliptical shape as shown in FIG. 5(a), or have slopes at the tops, etc. as shown in FIG. 5(b). Further, as shown in FIG. 5(c), the hole was likely to be formed in an inclined shape, such as becoming narrower as it became deeper. Therefore, there was a concern that light absorption would be uneven between thick and thin sunspot areas. Further, if the protrusion has an inclination, it causes scattered light.

Furthermore, when painting is performed, there is a problem that the light shielding rate of the paint varies depending on the wavelength, as shown in FIG. In addition, since vapor deposition and painting are performed, there is a problem in that even if the optical performance is good, the cost is high.

An object of the present invention is to provide a light absorber that does not generate uneven light absorption or scattered light and can be manufactured at low cost.

The inventors of the present invention have made the following findings as a result of intensive studies to solve the above-mentioned problems.

In other words, it is a finding that by forming a black dot-like film on the surface of a layer made of a photosensitive material by exposure, a light absorber that does not generate uneven light absorption or scattered light can be produced at low cost.

The present invention is based on the knowledge of the inventor, and the means for solving the above-mentioned problems are as follows.

<1> A light absorber characterized in that a black dot-like film is formed on the surface of a layer made of a photosensitive material by exposure to light.

<2> The light absorber according to <1>, wherein the photosensitive material is a photosensitive film, and the black dot-shaped film is formed by exposure to at least one of ultraviolet light and laser light.

<3> The light absorber according to <1> or <2>, wherein the film in the form of regular black dots is formed by exposing the film to ultraviolet light through a patterned photomask.

<4> The light absorption according to <1>, wherein the photosensitive material is a color resist, and the film is formed in the form of black dots by development after being exposed to ultraviolet light through a photomask on which a pattern is formed. It is the body.

<5> The light absorber according to any one of <1> to <4>, wherein the film has a light transmittance of 0.5% or less between 400 and 2,000 nm.

<6> The light absorber according to any one of <1> to <5>, which is used for optical elements of medical equipment and eyeglass equipment.

The light absorber of the present invention forms a black dot-like film on the surface of a layer made of a photosensitive material by exposure, so there is no uneven light absorption or scattered light, and the light absorber can be manufactured at low cost. It is possible to obtain a body.

In photosensitive film, Fig. 1(a) shows a method of forming a black dot-like film, Fig. 1(b) shows a method of forming a regular black dot-like film, and Fig. 1(c) shows a method of adjusting the light amount. FIG. FIG. 2 is a diagram showing a light absorber of the present invention made of a photosensitive film. FIG. 3 is a graph showing the wavelength dependence of the light shielding rate of the light absorber of the present invention. In color resist, FIG. 4(a) is a schematic diagram showing a method of forming a black dot-shaped film, and FIGS. 4(b) and (c) are both schematic diagrams showing a method of adjusting light amount. FIGS. 5(a) to 5(c) are diagrams showing conventional light absorbers. FIG. 6 is a graph showing the wavelength dependence of the light shielding rate of a conventional light absorber. FIG. 7 is a graph showing the light transmittance of the produced light absorber of the present invention. FIG. 8 is a graph showing the light transmittance of a light absorber manufactured by applying a paint.

[First form]
The light absorber of the first embodiment of the present invention is made of a photosensitive film.

The commonly known photosensitive film has a three-layer structure in which a photosensitive layer is sandwiched between a base film made of polyethylene terephthalate (PET) or the like and a cover film made of polyethylene (PE) or polypropylene (PP). Bye.

There are no particular restrictions on the photosensitive resin constituting the photosensitive layer if it is prepared from a composition solution consisting of components commonly used to obtain photosensitive resins, such as a binder, a polymerizable compound, and a photopolymerization initiator. There isn't. Furthermore, there are no particular limitations on the binder, polymerizable compound, and photopolymerization initiator as long as they are components commonly used in the production of photosensitive films, and they may also contain thermal crosslinking agents for forming solder resists. .

Furthermore, various known additives such as antioxidants, antistatic agents, surfactants, flame retardants, and dispersants may be added to the photosensitive resin within a range that does not impede the effects of the present invention.

For example, when a polyester-based photosensitive film is used, a light absorber can be produced with an exposure time of less than 0.1 seconds. As specific commercially available products, for example, Idealine RPF manufactured by AGFA, XPR-7S manufactured by Fuji Film, etc. can be suitably used.

In this embodiment, a black dot-shaped film for preventing light reflection is formed on this photosensitive film by exposure. Since this film has a light-shielding property, by forming this film, the present embodiment functions as a light absorber.

Specifically, as shown in FIG. 1(a), a film 11 is formed by exposing the surface of the photosensitive film 10 from which the cover film has been peeled off. This exposure may be ultraviolet (UV) exposure transmitted through a photomask, or may be irradiated directly onto the surface of the photosensitive film 10 with laser light.

Among these exposure means, the photomask is preferably a mask that can form a pattern, such as a chrome mask.If it is a chrome mask, it may be a single layer of chromium or a chromium layer with antireflection of chromium oxide (Cr ₂ O ₃ ). A film may also be deposited. Furthermore, the laser light may be of any color, such as white, red, green, or blue.

When a mask capable of forming a pattern is used, as shown in FIG. 1(b), by exposing the photosensitive film 10 to a photomask with a pattern formed in advance, a plurality of black dot-shaped films 11 are formed regularly. can be formed. This regularly formed film can be applied as a scale, encoder, diffraction element, etc.

Furthermore, as shown in FIG. 1(c), if UV exposure is performed on the surface of the photosensitive film 10 through photomasks having different film thicknesses, the light amount can be adjusted so that the light transmittance is, for example, 50 to 100%. You can also do

As shown in FIG. 2, the film 11 thus obtained is formed in a vertical direction without any inclination, so that there is no unevenness in depth. Therefore, it is possible to prevent uneven absorption due to differences in the position of light. Furthermore, since the element is not an element that protrudes onto the layer of the photosensitive film 10 like a protrusion, generation of scattered light can also be prevented.

Furthermore, since it is formed by exposure to light, there is no wavelength dependence of the light absorption rate (shading rate), unlike when it is formed using paint, and as shown in Figure 3, it remains approximately constant regardless of the wavelength of the light. It can absorb light with a shading rate. In addition, since the film is formed only by exposure, it can be formed at a lower cost than vapor deposition or painting.

Here, the light transmittance for the purpose of light shielding is preferably consistently 0.5% or less between 400 and 2000 nm, and more preferably less than 0.2%. This light transmittance can be measured using a commercially available optical densitometer, and for example, an optical densitometer manufactured by X-rite (X-rite Exact) can be suitably used.

Further, the film obtained by exposure is subjected to development and fixing. There are no particular restrictions on the developing and fixing methods in this case, and the methods may be selected by selecting appropriate conditions depending on the photosensitive film used.

For example, for development, use AGFA's physical developer (PDEV) at a development speed of 20 to 40 seconds and a development temperature of 35 to 38°C, with a developer replenishment amount of 250ml/ ^m2 , which is an additional 2L per day. It is preferable to use it at a pace that is suitable for you. In that case, for fixing, use the same company's physical fixer (PFIX) at a fixing replenishment rate of 350 ml/mm ² to darken the area by 50%, and then wash with water at room temperature of about 20°C. is preferred.

In addition, after developing for 30 seconds using a developer with a liquid temperature of 35°C in a dark room at a temperature of 20°C and a humidity of 50% using a developer ND-1 manufactured by Fujifilm, for example, It is also suitable to carry out fixing using fixer solution NF-1 manufactured by Co., Ltd.

Although substances containing sulfur components such as sodium thiosulfate are sometimes used in the fixing solution, it is preferable that the sulfur components contained in these substances be sufficiently removed during development. The presence or absence of a sulfur component may be determined using a commercially available fluorescent X-ray sulfur analyzer or a general solution conductivity measurement method as appropriate.

The thickness of the light absorber of the present invention is not particularly limited and is usually about 10 to 40 μm; It becomes possible to make it thinner.

[Second form]
The light absorber according to the second embodiment of the present invention is made of a color resist.

Color resists are generally the same as described in the first embodiment except that red (R), green (G), and blue (B) colorants are added to the photosensitive resin. What is used at the time of production may be appropriately selected.

In this embodiment, a black dot-shaped film for preventing light reflection is formed on the color resist by exposure. By forming this film, this embodiment functions as a light absorber.

Specifically, as shown in FIG. 4A, the surface of the color resist 20 is exposed to UV light through a photomask in which a pattern has been formed in advance, and then developed to form a black dot-shaped film 21. do. Depending on the pattern formed on the photomask, this film 21 may be formed singly as in the example on the right side of the figure, or as in the example on the left side of the figure, a plurality of films 21 may be formed regularly to prevent diffraction. It can also function as an element or the like.

In this case, development conditions may be selected appropriately according to the color resist used. For example, development may be carried out under the conditions listed in the first embodiment, and then fixing may be carried out. preferable.

It is also possible to adjust the light amount, and as shown in FIG. 4(b), the light transmittance can be made uniform over the entire surface, for example, 50%, or as shown in FIG. It is also possible to adjust the light transmittance to, for example, 50 to 100% by transmitting the light through photomasks having different thicknesses.

Further, in the examples shown in FIGS. 4(a) to 4(c), the pattern is formed using a photomask, but it may be exposed to laser light as in the first embodiment.

The film thus obtained protrudes in the vertical direction, has a flat top, and does not have any inclination, so there is no unevenness in thickness. Therefore, it is possible to prevent uneven absorption and scattering due to differences in the position of light. Further, as in the first embodiment, there is no wavelength dependence, it can be manufactured at low cost, and the layer thickness of the light absorber can be made relatively thin.

[Other forms]
In addition, the light absorber of the present invention is not limited to the above-mentioned forms; for example, the photosensitive material may be obtained by etching a metal film to form a pattern using a non-color resist using photolithography. good.

Since the light absorber of the present invention has high light-shielding properties, it is used in devices that obtain information using light, that is, optical devices that require adjustment of light intensity and optical path, and removal of reflected light that causes ghosts and flares. It can be suitably used for. It is especially suitable for medical and eyeglass equipment-related applications that require optical elements that absorb and remove harmful reflected light and scattered light called sunspots, black spots, and spots that occur in the cornea and crystalline lens of the eye. It can be used for.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Example 1)
A red-sensitive photo touring film (Idealine RPF manufactured by AGFA), which is a polyester-based photosensitive film and has a thickness of 0.18 mm, was exposed to a red laser beam with a wavelength of 633 nm for 0.07 seconds to form a film with a diameter of 0.5 mm. A black dot-shaped light absorber as shown in FIG. 1(a) was prepared.

When the light transmittance (%) between 400 and 2,000 nm of the obtained sunspots was measured using an optical densitometer manufactured by X-rite (X-rite Exact), as shown in Figure 7, the light transmittance (%) was consistently It was less than 0.2%, and light could be almost certainly blocked regardless of the wavelength.

(Example 2)
A sunspot was prepared in the same manner as in Example 1, except that the exposure light was changed to red semiconductor laser light with a wavelength of 670 nm, and the light transmittance was measured in the same manner as in Example 1. It was found that it was almost reliable regardless of the wavelength. It was possible to block out the light.

(Example 3)
The black dots were removed in the same manner as in Example 1, except that the red-sensitive photo touring film was replaced with a blue-green sensitive film (AGFA's Idealine OPF) based on the same polyester, and exposed to green laser light with a wavelength of 500 to 530 nm. When the light transmittance was measured in the same manner as in Example 1, it was found that light could be blocked almost reliably regardless of the wavelength.

(Example 4)
A black spot was prepared in the same manner as in Example 3, except that the blue-green sensitive film of Example 3 was exposed to blue argon laser light with a wavelength of 488 nm, and the light transmittance was measured in the same manner as in Example 3. It was possible to block light almost reliably, regardless of the wavelength.

(Example 5)
Fujifilm XPR-7S as a photosensitive film was exposed to laser light with a wavelength of 647 nm under the conditions of a laser spot size of 0.004 mm and a laser feed pitch of 0.001 mm, and the size was the same as in Example 1. A black dot-shaped film with a diameter of 0.5 mm was drawn. After that, the drawn film was developed for 30 seconds in a dark room at a temperature of 20°C and a humidity of 50% using a developer (ND-1 manufactured by Fujifilm) at a temperature of 35°C, and then fixed. After fixing using a liquid (NF-1 manufactured by Fuji Film Corporation), the light absorber was prepared by washing with water and drying.

When the light transmittance of the obtained sunspots was measured in the same manner as in Example 1, it was found that light could be almost reliably blocked regardless of the wavelength.

(Comparative example 1)
The light transmittance was measured in the same manner as in Example 1 for a black dot-shaped light absorber prepared by punching holes in a photosensitive film and painting the holes with SK Giken's Miraku Primer SR as a black paint. The results are shown in FIG.

(Comparative example 2)
The holes in the photosensitive film were painted in the same manner as in Comparative Example 1, except that the black paint was changed to BS-421A BLK SD manufactured by Toyo Kogyo Co., Ltd., and the light transmittance was measured in the same manner as in Example 1. The results are shown in FIG.

(Comparative example 3)
The holes in the photosensitive film were painted in the same manner as in Comparative Example 1, except that the black paint was changed to Toray Photoblack, and the light transmittance was measured in the same manner as in Example 1. The results are shown in FIG.

As shown in FIG. 8, in the light absorbers of Comparative Examples 1 to 3, a tendency to increase was observed at wavelengths exceeding 900 nm.

These results show that the light absorber of the present invention, which is fabricated by exposing the surface of a layer made of a photosensitive material, has almost no wavelength dependence, and is more effective than a light absorber fabricated by painting using conventional methods. It was found that the material exhibited extremely excellent light absorption ability.

Although the embodiments of the present invention have been described in detail above, the light absorber of the present invention is not limited to the above embodiments, and may include any technical ideas envisioned within the scope thereof.

INDUSTRIAL APPLICABILITY The present invention can be widely used in optical devices such as medical equipment that require adjustment of light intensity and optical path, removal of reflected light that causes ghosts and flares, and the like.

10 Photosensitive film 11, 21 Film 20 Color resist

Claims (2)

A method for manufacturing a light absorber used for optical elements of medical equipment and eyeglass equipment, the method comprising:
The surface of the layer consisting of a photosensitive film is coated with black dots , which are not elements that appear on the layer of the photosensitive film, and have a light transmittance of 0.5% or less between 400 and 2,000 nm when exposed to colored laser light. form a film ,
A method for manufacturing a light absorber, characterized in that the light absorber can be applied to the optical element that absorbs and removes harmful reflected light or scattered light generated by the cornea or crystalline lens of the eye. 2. The method for producing a light absorber according to claim 1, wherein the photosensitive film to be exposed contains silver halide.