JPS6069602A - Composition for near ir transmission filter and near ir transmission filter using said composition - Google Patents

Abstract

PURPOSE:To eliminate malfunction of a remote control for a television, etc. of the type using rays by adsorbing I2 in a specific amt. range on a sheet or film of a polyvinyl alcohol (PVA) so that light of particularly short wavelengths except near IR is made non-transmittable. CONSTITUTION:A sheet or film of PVA is used as a base body 2. The base body is immersed for one minute in a compsn. soln. prepd. by dissolving 5g I2 and 50g KI in 1l water, by which the compsn. adsorbed with I2 in a 0.1-5.0g/m<2> range for a near IR transmittable filter is manufactured. The base body 3 is immersed for 3min in an aq. soln. contg. 20g/l boric acid after adsorption of I2 and is then dried by warm air to make the base body resistant to water. Cellulose triacetate films or the like are adhered by an adhesive agent 3 to both surfaces of the body 2 subjected to such treatment to form protective layers 4. A sealant 5 consisting of silicone or the like is applied on the end face of the filter. The filter having excellent transmittivity of near IR, particularly 950- 1,000nm is thus obtd. The transmittivity of other wavelength light is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a near-infrared transmitting filter composition and a near-infrared transmitting filter using the composition.

In this specification, "Near-infrared transmitting filter" 8R refers to near-infrared rays, particularly 950 to 100 nm.
It means a filter that transmits light having a wavelength of 80% or more with a high transmittance of 80% or more, and substantially blocks the transmission of light other than near infrared rays, especially light having a wavelength similar to 800 nm or more.

For light-based remote control devices for electrical appliances such as televisions, radios, stereos, and day recorders,
Near-infrared rays are often used as the light beam, but in order to prevent malfunctions caused by light rays other than near-infrared rays, it is necessary to provide a near-infrared transmitting filter as defined above in the light receiving section of the device.

Conventionally, as this type of filter, a filter obtained by adding an anthraquinone-based oil-soluble dye to a base material made of a synthetic resin with good light transmittance is known (Japanese Patent Application Laid-Open No. 1983-1972).
(Refer to Publication No.-159453). However, this filter does not block the transmission of light rays with a wavelength of 900-1000 nm, and substantially blocks the transmission of light rays with a wavelength shorter than 750 nm.
In the 800 nm range, the transmittance of light cannot be kept low, and therefore, this transmitted light causes malfunctions of the remote control device.

This invention was made in view of the above-mentioned circumstances, and it suppresses the transmittance of light rays with wavelengths shorter than 800nlll to 20% or less, and also suppresses the transmittance of light rays with wavelengths shorter than 800nlll, and
An object of the present invention is to provide a near-infrared transmitting filter that can transmit light having a wavelength of 00 nm with a transmittance of 80% or more.

The first thing according to the present invention is a near-infrared ray comprising a base material made of polyvinyl alcohol resin (hereinafter abbreviated as PVA) and iodine absorbed into the base material at 0.1 to 5.00/m2. The second invention is a composition for a transmission filter, and a filter base is formed of the above composition, and protective layers made of glass or synthetic resin with good light transmittance are provided on both sides of the base. It is an infrared transmission filter.

In the first invention, the PVA base material is usually in the form of a sheet or a film. Adsorption of iodine onto the PVAIU substrate is carried out, for example, by immersing the PVA substrate in an aqueous solution containing an iodide such as potassium iodide and iodine at a desired concentration for a required period of time. The filter composition thus obtained is then treated with rllll M aqueous solution in order to impart water resistance to the PVA.

Iodine absorption is 0.1 to 5 per surface area of PVA, Oo/
The reason why it is limited to the range of m2 is that below the lower limit of the above range, the total light transmittance for wavelengths shorter than 800 nm will be 20% or more, and when the light receiving part of the remote control device receives strong sunlight or illumination light, This is because malfunction occurs due to transmitted light, and if the upper limit of the above range is exceeded, the transmittance in the near-infrared region, particularly in the range of 950 to 1000 nIIl, decreases to 80% or less, making it unsuitable as a near-infrared transmitting filter.

In the second invention, examples of the synthetic resin with good light transmittance constituting the protective layer include acrylic resin, styrene resin, cellulose resin, vinyl chloride resin, and polycarbonate resin. Then, as shown in FIG. 1(a), a film or sheet-like filter 1ffi (1) made of glass or synthetic resin is attached to the filter base (
2) via adhesive (3), or apply a synthetic resin liquid to both sides of the filter base (2) to form a coating. Protection of F
2j (4), or further, as shown in the same figure (c), a protective layer (1) made of glass or synthetic resin is placed on both sides of the filter base (2), and a silicon-based coating is applied to the end face. By providing a sealing material (5) such as the above, a near-infrared transmitting filter is constructed. Note that in both cases, the filter base and the protective layer are integrated with a fixed frame.

The filter constructed in this way suppresses the transmission of light rays with wavelengths shorter than 800 nm to a transmittance of 20% or more, and transmits near-infrared rays, especially light rays with a wavelength of 950 to 100011 m, with a transmittance of 80% or more. Tear) C, remote 1
- It is suitable as a constituent filter of a control device.

Embodiments of the present invention will be described in detail below.

An aqueous solution for iodine adsorption was prepared by dissolving potassium iodide 50a and iodine 59 in water No. 11, and a 75μ thick P V
ΔThe film was immersed for 1 minute.

In this way, iodine is added to 0.5 (1/n+
2 sucked names. Next, the iodine-absorbing PVA film was immersed in a boric acid aqueous solution prepared by dissolving 20 q of boric acid in 1/2 water for 3 minutes to make it waterproof, and then dried with hot air at 80°C. In this way, a silk composition for a near-infrared transmission filter was produced.

Using the obtained composition as it is as a filter substrate,
On both sides of this, the size J shown in Figure 1 (a): sea urchin, thickness 0.
A 2non transparent triacetic acid cellulose film was attached via a hydrophilic acrylic resin adhesive. In this way, a near-infrared transmission filter was manufactured.

I recorded the light transmittance of the obtained filter using a spectrophotometer (Island) 4! As shown in Figure 2, the transmission of light with a wavelength shorter than 8000n1 is completely blocked by the transmitted SO, and the near-infrared rays, especially those with a wavelength of 950nm, are completely blocked. The transmittance of the above light rays is 85%.
It passed through.

[Brief explanation of the drawing]

FIGS. 1(a), 2(b), and 3(c) are cross-sectional views of a near-infrared transmitting filter, and FIG. 2 is a graph showing the relationship between wavelength and transmittance. (1)...protective layer, (2)...filter base.

Claims (2)

[Claims] (1) A composition for a near-infrared transmitting filter consisting of a base material made of polyvinyl alcohol resin, and iodine and J2 adsorbed on the base material. (2) The filter base is composed of a composition made of a polyvinyl alcohol resin base material and 0.1 to 5.0 g/m2 of iodine adsorbed on the base material, and glass with good light transmittance is coated on both sides of the base. A near-infrared transmitting filter with a protective layer made of synthetic resin.