CN1170879A

CN1170879A - Light filter

Info

Publication number: CN1170879A
Application number: CN 96102062
Authority: CN
Inventors: 邱励楠; 邱行中
Original assignee: QIU LI'NAN
Current assignee: QIU LI'NAN
Priority date: 1996-02-11
Filing date: 1996-02-11
Publication date: 1998-01-21

Abstract

The light filter system consists of slit, the first collimating lens, beam splitter, the second collimating lens and optical filter with special pattern in it. After light passes through the said optical system, the spectral band formed on the optical filter is filtered through the special pattern. Therefore, the said system has optional spectral transmittance and it has wide application range. It may be used in various standard optical source and precision colorimeter as well as in astronomy, colorimetry, optical communication and other fields.

Description

Filtering apparatus

The present invention is a kind of manufacture method of novel filtering apparatus.

Optical filter light is widely used in fields such as photograph, TV, tintmeter, microscope, uranology, colorimetry, photometry and optical communication.Optical filter is of a great variety, have solid, liquid, also have gas.By the absorption filter that utilizes compound to form, use the optical filter of dispersion phenomenon, use the interference filter of interference and birefringent filter etc. in addition.From spectral transmittance, neutral colour filter, gradual change cut-off type optical filter, precipitous type cut-off type optical filter are arranged, also have broad band pass filter and narrow band pass filter.The spectrum transmitting rate curve of existing optical filter all is smoother and well-regulated various combinations by optical filter, can make it have the spectral transmittance of some appointment.But this combination is very complicated, and can only obtain the spectral transmittance of some appointment comparatively approx.Obtaining the spectral transmittance of any appointment, for example have the spectral transmittance of zigzag fashion, use above-mentioned various optical filter and combination thereof, is extremely difficult, or even impossible.

Task of the present invention provides a kind of novel filtering apparatus, and it has the spectral transmittance of any appointment.

The basic optical structure of this filtering apparatus as shown in Figure 1.S is a slit, and L1 is the 1st collimation lens, and S is on the front focal plane G1 of L1, and M is beam splitter (prism or a grating), and L2 is the 2nd collimation lens, and F is an optical filter, and F is positioned on the back focal plane G2 of L2.Special pattern is arranged on optical filter F, this optical filter can be a transmission-type, adopt transparent material this moment, for example glass sheet, organic glass sheet, transparent plastic sheet etc., optical filter also can be reflective, adopts this moment such as the glass sheet of sheet metal with certain reflectivity or metal-plated membrane or plastic sheet etc.

The optical filtering principle of this device is as follows:

Ambient light converts a branch of directional light to after passing through slit S and the 1st collimation lens L1.This bundle directional light becomes the different monochromatic collimated beam in the direction of propagation by behind the beam splitter M.The 2nd collimation lens is arranged in band according to the wavelength size with above-mentioned monochromatic light on F (being positioned at back focal plane G2).For wavelength in the band is the zone of λ, adopts special geometric scheme that the spectral transmittance T (λ) or the spectral reflectivity R (λ) of appointment correspondingly are set on F.For example for the transmission-type optical filter, the part of black pattern is arranged, light can not pass through.The part of no black pattern, light can all pass through.Suppose that to all wavelengths the transmitance of glass is 100%.Equal in the zone of λ ratio C (the λ)=T (λ) of the total length (perhaps gross area) in length of non-black area of the pattern (perhaps area) and λ zone corresponding to wavelength on the band.The filtering apparatus of Huo Deing has spectral transmittance T (λ) like this.If the spectral transmittance of glass is T1 (λ), as long as then make C (λ)=T (λ) ÷ T1 (λ), the device of Huo Deing still has spectral transmittance C (λ) so.For reflection optical filter, situation is similar.

As long as make F go up the position of pattern and the position inregister of band, then change the shape (length or the area size of black part) that F goes up pattern, just can obtain the spectral transmittance of any appointment.

Pattern on the F can adopt the photo-optics method to obtain, and also can adopt other method manufacturing.

M can be single prism or grating, also can adopt a plurality of prisms or a plurality of grating or a plurality of prism and grating to mix and form.

In fact optical filter F can be called spectral filter.It is after forming band, in different zones monochromatic light to be filtered respectively through prism or grating beam splitting at mixed light, therefore adopts such filtering apparatus, can obtain the spectral transmittance of any appointment.

, therefore can obtain to use widely owing to can obtain the spectral transmittance of any appointment according to filtering apparatus of the present invention, for example can be used to make various standard sourcess, be used to make high precision colorimeter and other many fields.

Explain detailedly with example below.

Example 1 has the manufacturing with the filtering apparatus of photopic vision function V (λ) identical spectra transmitance

The filtering apparatus structure as shown in Figure 1.Optical filter F can prepare according to following method: if adopt transmission-type, can select a transparent neutral density glass or quartz glass plate P, promptly to the light of all wavelengths, its transmitance all is the same.In addition, suppose that transmitance is 100%.If P is on the position of G2, the overall optical bands of a spectrum just in time are positioned on the rectangular area ABCD of P, on P, part beyond the band zone that ambient light forms is all made black, light can not be by (also can not make black) certainly, at the band wavelength is on the point of λ, the length of non-black part and ratio C (the λ)=V (λ) of the total length of luminous component.For example during λ=520nm, V (520)=0.71, then C (520)=71% is according to same principle, and in the whole zone of band, the black region that can draw is as Fig. 2.As can be seen from Figure 2, the shape in non-black zone is just in time consistent with photopic vision function curve V (λ).Black region can have various selections.Can adopt different patterns, still, no matter adopt any pattern, the non-black partial-length should be V (λ) with the ratio C (λ) of the total length of light emitting region.If the transmitance of glass is N (λ), C (λ)=V (λ) ÷ N (λ) then.For reflection optical filter, can adopt same principle preparation.If the reflectivity of this optical filter is R (λ), then use the transmitance N (λ) in reflectivity R (λ) the replacement following formula.

The manufacturing of example 2 neutral filtering apparatus

The filtering apparatus structure as shown in Figure 1.Beam split optical filter F can prepare as follows: if adopt transmission-type, can select a transparent neutral density glass or quartz glass plate P, promptly to the light of all wavelengths, transmitance all is the same.In addition, suppose that transmitance is 100%.In order to obtain transmitance is 57% neutral filtering apparatus.If P is on the position of G, the overall optical bands of a spectrum just in time are positioned on the rectangular area ABCD of P, then make rectangle EFGH part in addition all make black (light can not pass through), and the part beyond EH=0.57 * AD.ABCD also can not made black, as Fig. 3. like this filtering apparatus that obtains be a neutrality, promptly to the light of any wavelength, transmitance all is the same, and all equals 57%.Certainly, black region also can be made other pattern.But no matter adopt any pattern, the length of black part should be constant with the ratio C (λ) of the total length of luminous component, and all is 57%.If the transmitance of glass is not equal to 100%, and glass is not strict neutral density glass, according to top similar principle, by simple computation, can make transmitance yet and be 57% neutral filtering apparatus.

Example 3 has the manufacturing of the filtering apparatus of zigzag spectral transmittance

The filtering apparatus structure is the same.For (λ=500,505 and 510nm for example that obtain to have the zigzag spectral transmittance ... the time, transmitance is respectively 45%55% and 50% ...) filtering apparatus, available following step: if still adopt transmission-type, can select a transparent neutral density glass or quartz glass plate P, promptly to the light of all wavelengths, transmitance all equates.Still suppose that in addition transmitance is 100%.If P is on the position of G2, the overall optical bands of a spectrum just in time are positioned on the rectangular area MNOP of P.The MN limit is cut apart at interval according to 5nm, made rectangle MNOP be divided into several little rectangles.And make in each rectangle, the area in non-black zone equates with the transmitance of respective wavelength respectively with the ratio of rectangular area.For example in 497.5-502.5nm, 502.5-507.5nm, 507.5-512.5nm scope (corresponding with rectangle ABGH, BCFG and CDEF respectively), the area in non-black zone is respectively 45%, 55%, 50% with the ratio of corresponding rectangular area, as Fig. 4. the pattern of black region can freely be selected, but no matter adopt any pattern, the black region gross area should equate with the spectral transmittance C (λ) of respective wavelength respectively with the ratio of rectangle gross area.The filtering apparatus of Huo Deing has jagged spectral transmittance like this.

Fig. 1 is the basic optical structural drawing of filtering apparatus of the present invention.S is a slit, and L1, L2 are respectively the 1st collimation lens and the 2nd collimation lens, and M is a beam splitter, and F is an optical filter, and G1 is the front focal plane of L1, and G2 is the back focal plane of L2.

Fig. 2 is a kind of figure of optical filter.

Fig. 3 is the another kind of figure of optical filter.

Fig. 4 is the third figure of optical filter, and regional ADEH is the part of region-wide MNOP.

Claims

1. filtering apparatus of forming by slit, the 1st collimation lens, beam splitter, the 2nd collimation lens and optical filter, it is characterized in that special pattern is arranged on the optical filter, and the position inregister of the position of pattern and band on the optical filter, by changing the shape of pattern on the optical filter, just can obtain the spectral transmittance of any appointment.

2. according to the filtering apparatus of claim 1, optical filter can be a transmission-type, adopt transparent material this moment, for example glass sheet, organic glass sheet, transparent plastic sheet etc., optical filter also can be reflective, adopts this moment such as the glass sheet of sheet metal with certain reflectivity or metal-plated membrane or plastic sheet etc.

3. according to the filtering apparatus of claim 1, beam splitter can be single prism or grating, also can adopt a plurality of prisms or a plurality of grating or a plurality of prism and grating to mix and form.