JPH07157517A - Production of metal-containing resin and lens made of the resin - Google Patents

Abstract

PURPOSE:To obtain a metal-containing resin useful for a lens having near- infrared cutting function by reacting a copolymer of methyl vinyl ketone and methyl methacrylate with phosphorus trichloride and adding polymethyl methacrylate and copper nitrate to the reactional product. CONSTITUTION:This metal-containing resin is produced by reacting (A) 2 pts.wt. of a copolymer obtained by compounding and copolymerizing (i) 2-28 pts.wt. of methyl vinyl ketone, (ii) 97-70 pts.wt. of methyl methacrylate and (iii) 0.5 pts.wt. of a polymerization initiator with (B) 0.1-0.6 pts.wt. of phosphorus trichloride and compounding 0.5 pts.wt. of the obtained copolymer with (C) 10 pts.wt. of polymethyl methacrylate and (D) 2-4 pts.wt. of copper nitrate trihydrate. A lens having near-infrared cutting performance can be manufactured by using the resin as the lens material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-performance filter material by introducing a metal compound into a transparent resin at a high concentration, and a lens using the same.

[0002]

2. Description of the Related Art An optical device using a CCD solid-state image sensor,
For example, a camera or a bar code reader uses C through a lens.
If near-infrared light is included in the light imaged on the CD element, it becomes noise. Therefore, a filter is arranged in the optical system and only visible light is made incident on the CCD element. Further, this filter for cutting near infrared light is used not only for CCD elements but also for photodiodes and the like.

Filters for cutting near infrared light include those made of glass and those made of plastic. As shown in the spectral characteristic example of FIG. 3, the glass filter is used for visible light (wavelength 4
Good filter characteristics of about 90% in the transmittance for 00 nm to 700 nm) and about 0% in the transmittance for near infrared light (wavelength of 700 nm) are obtained. This glass filter is made by dissolving copper sulfate in silica and dispersing copper ions Cu ⁺ in the glass.

However, the glass filter is difficult to form, and is only commercialized as a flat plate filter.
Therefore, it is unsuitable for mass production as a lens having a near-infrared light cutting function, which is used as a material of an aspherical lens used in place of a combination lens, for example.

On the other hand, the plastic filter can be formed into an arbitrary shape by a resin molding technique such as injection molding, so that aspherical lenses can be easily mass-produced.

However, the conventional plastic filter has a filter characteristic as shown in the spectral characteristic example of FIG.
It was inferior to the one made of glass.

The plastic filter is obtained by introducing a metal compound into a transparent resin. The conventional methods for this are as follows: a method of adding a metal salt to (meth) acrylic acid ester to polymerize, a method of copolymerizing in the presence of (meth) acrylic acid, a method of using a monomer having a polar group in the molecule It was a method of adding a salt and polymerizing.

In these methods, only a small amount of metal is introduced, and as shown in the spectral characteristic example of FIG. 2, when the concentration of the dye, which is a metal complex of copper, is small (the weight ratio to the plastic material is 0.02%), near infrared light (700n
When the cut rate of m-) becomes worse and the concentration of dye is increased (0.1% by weight), visible light (400-700 nm)
Transmittance is reduced to 25% or less. Even if the transmittance of visible light is maximized at the sacrifice of the cutoff rate of infrared rays, it can only be about 70%.

In this respect, the plastic filter has a visible light transmittance of 90% while cutting almost 100% of near infrared light.
%, Which does not reach the glass filter shown in FIG.
In an optical device using a CD element, it was not possible in terms of performance to provide the lens itself with a function of cutting near-infrared light so as to simplify the structure.

[0010]

Therefore, the present invention is
An object of the present invention is to provide a method for producing a metal-containing resin having the same characteristics as a glass filter, and to make a lens used in an optical device using a CCD element have a function of cutting near-infrared light to simplify the configuration. And

[0011]

[Means for Solving the Problems]

(1) The method for producing a metal-containing resin provided by the present invention is performed by using methyl vinyl ketone (MVK) and methyl methacrylate (MM).
Copolymerizing A) into a copolymer,

[0012] The step of causing phosphorus trichloride (PCl ₃ ) to act on the copolymer, the copolymer treated with phosphorus trichloride is hydrolyzed, and copper nitrate is added to form a blue metal-containing resin. ) To obtain a resin.

(2) The specific compounding ratio of the invention of (1) above is as follows.

Methyl vinyl ketone (MVK) 2 to 28 parts by weight methyl methacrylate (MMA) 97 to 70 parts by weight Polymerization initiator 0.5 parts by weight was added to the copolymer, and the treatment with phosphorus trichloride was carried out. 2 parts by weight Phosphorus trichloride 0.1 to 0.6 parts by weight, and the final blend is a phosphorus trichloride-treated copolymer 0.5 parts by weight Polymethylmethacrylate (PMMA) 10 parts by weight Copper nitrate trihydrate 2 ~ 4 parts by weight
The composition of

(3) The metal-containing resin produced by the method of the present invention is used as a lens material to obtain a lens having a near-infrared light cutting function.

[0016]

In the above manufacturing method, a phosphoric acid group is introduced into a copolymer of methyl vinyl ketone (MVK) and methyl methacrylate (MMA) to form a chelate with copper. The contained resin can be obtained.

A lens made of this resin serves as a lens having a function of a near infrared light cut filter.

[0018]

EXAMPLE 15 g of methyl vinyl ketone (MVK), 78 g of methyl methacrylate (MMA), and 2,2′-azobisisobutyronitrile (AIB) as a polymerization initiator
N) 0.4 g is mixed. This mixture is kept at 60 ° C. for 24 hours by a sealed tube method to obtain a copolymer.

Next, 2 g of this copolymer was dissolved in 20 ml of tetrahydrofuran, and this solution was added to 30 ml.
Keep at ° C, add 0.2 g of phosphorus trichloride dropwise with stirring, and stir for another 24 hours.

The mixture after the reaction was put into water,
Hydrolysis is performed to precipitate the polymer.

To 0.5 g of this polymer, 2 g of copper nitrate trihydrate [Cu (NH ₃ ) .3H ₂ O] and 10 g of polymethylmethacrylate (PMMA) were added to tetrahydrofuran (T).
HF) was dissolved in 200 ml and dried on a glass plate to form a film.

As shown in FIG. 1, the spectral characteristics of this film have a transmittance close to 90% in the visible light region,
The transmittance is 0% in the near infrared region.

The metal-containing resin of the present invention is molded into the above-mentioned film shape, and by forming it into a predetermined lens shape, a lens having an arbitrary shape including an aspherical lens has a function of a near infrared light cut filter. Can be produced. As a result, the optical system of the optical device having the CCD element can be simplified, and the cost can be reduced without lowering the optical performance.

[0024]

According to the present invention, a plastic filter having the same characteristics as a glass filter can be manufactured, and a lens having an arbitrary shape having a near-infrared light cutting function can be manufactured by utilizing the ease of molding of plastic. it can.

[Brief description of drawings]

FIG. 1 is a spectral characteristic diagram of a metal-containing resin produced by the present invention.

FIG. 2 is a spectral characteristic diagram of a conventional plastic filter.

FIG. 3 is a spectral characteristic diagram of a glass filter.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshinori Itaya, 3-2-30 Minamieguchi, Higashiyodogawa-ku, Osaka City, Osaka Prefecture Japan Aspherical Lens Co., Ltd. (72) Inamu Kei Tokumura Minami, Higashiyodogawa-ku, Osaka City, Osaka Prefecture Eguchi 3-chome 2-30 Japan Aspherical Lens Co., Ltd.

Claims (3)

[Claims] 1. A step of copolymerizing methyl vinyl ketone and methyl methacrylate to form a copolymer, a step of allowing phosphorus trichloride to act on this copolymer, and hydrolyzing the copolymer treated with phosphorus trichloride to give copper nitrate and polymethacryl A method for producing a metal-containing resin, which comprises obtaining a resin by adding methyl acid. 2. A copolymer is formed by compounding 2 to 28 parts by weight of methyl vinyl ketone (MVK), 97 to 70 parts by weight of methyl methacrylate (MMA), and 0.5 part by weight of a polymerization initiator. The treatment was carried out with the compound of 2 parts by weight of phosphorus trichloride 0.1 to 0.6 parts by weight, and the final step was 0.5 parts by weight of phosphorus trichloride-treated copolymer 10 parts by weight of polymethylmethacrylate (PMMA) copper nitrate trihydrate. Japanese products 2-4 parts by weight
2. The method for producing a metal-containing resin according to claim 1, wherein 3. A lens made of a metal-containing resin manufactured by the manufacturing method according to claim 1.