JPS6015603A - Light-attenuating filter - Google Patents

Abstract

PURPOSE:To enable uniform attenuation of UV, visible and IR light by working a non-light transmittable material consisting of a metal, etc. into the form of a mesh, cotton, fiber or foam. CONSTITUTION:A light-attenuating filter 2 has fine metallic wires 1 formed like a mesh. The quantity of the light to be attenuated is increased by increasing the number of the wires 1 to diminish the openings of the mesh. The uniform attenuation of the light from IR to UV is made possible in such a case. A material such as an opaque fiberous resin or the like which does not allow the transmission of light is also usable in place of the fine metallic wires and the material made into the form of not mesh but cotton, fiber or foam is equally usable. The material may be a resin in the case of foam but may also be a metal or an expandable metal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a neutral density filter used, for example, in a fluorescent lifespan needle, etc., and its entire purpose is to uniformly attenuate light from infrared to ultraviolet.

Items that can be used for the purpose of reducing light include ND filters (variable density filters, ring-shaped variable filters), light shielding plates, and diaphragms. ND filters have a disadvantage in that their transmittance is wavelength dependent, particularly in the ultraviolet region, where the transmittance becomes zero. On the other hand, although light shielding plates and squeezers do not have such drawbacks,
If the attenuation edge is changed, the cross-sectional area of the optical path also changes, so there is a drawback that it is difficult to measure under the same conditions, that is, it is difficult to maintain a constant S/N ratio.

In view of this, the present invention provides a complete neutral density filter that can uniformly attenuate light from infrared to ultraviolet with wavelength dependence α without changing the optical path cross-sectional area. be.

Hereinafter, the present invention will be described in detail based on the drawings.

Figure 1 shows a neutral density filter (2) made up of thin metal wires (1) arranged in a mesh shape. The amount of light attenuation can be increased by increasing the number of thin metal wires (1) and reducing the size of the mesh. Since the amount of light attenuation in cases -1, - is determined by the size of the mesh, which is independent of wavelength, light can be uniformly attenuated from infrared to ultraviolet. In addition, instead of the gold 14 thin wire, it is possible to use a material that does not transmit light, such as opaque wt thin horizontal wire, and even if it is not mesh-like, it can be cotton-like or fibrous-like as shown in Figure @2. Furthermore, it can also be made into a foamed form (limited to those having communicating holes). In the case of foam,
The material may be resin or metal. Therefore, it is also possible to use what is called a foamable metal. For example, nickel is a good material, but stainless steel, brass, etc. can also be used depending on the degree of dimming. As an example of the manufacturing method, there are four ways to obtain a porous filter by dissolving a nickel solution into a foam and then melting only the foam. In FIG. 3, ■■■ indicates the wavelength versus transmittance characteristics of the foamable metal. ■■ in the figure is a characteristic curve of a conventional ND filter.

To change to 11 using the above neutral density filter,
This can be done by overlapping items of the same or different types. Also, in order to change the light attenuation (tt) with a single filter, it is best to use the method shown in %@4 or Figure 5. That is, the neutral density filter (2) is formed to have a triangular shape in its entire cross section, and is moved in the direction that intersects the entire optical path (3) with IB. It is made of foamed rubber with a certain wavelength, and is sandwiched between transparent glasses (51 (5)) that have no wavelength dependence, and the distance between the glasses is changed to St (Fig. 5).

As explained above, fct effective.

■ The above-mentioned mesh-like, cotton-like, etc. processed materials have no wavelength dependence. 9 Ultraviolet and visible colors can be combined appropriately or completely changed in thickness.

Arbitrary uniform light attenuation is possible over the infrared range without changing the optical path cross-sectional area.

(2) It is less expensive than ND filters, etc., and can be cut into pieces of appropriate size, making it highly workable.

[Brief explanation of drawings]

'@ Figure 1 is a perspective view of a light filter as an embodiment of the present invention, the second figure is a perspective view of a neutral density filter as another embodiment of the present invention, and Figure 3 is a wavelength diagram of foam metal. The graphs showing the characteristics of transmittance, Figures 4 and 5 are diagrams showing a configuration for completely changing the light density cover using a single light density filter. (2) (4)...Dark filter.

Claims (1)

[Claims] Materials that do not allow light to pass through, such as metals and resins, are made into mesh-like, cotton-like,
A dimming eyelid letter processed into a fibrous or foamed form.