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Band pass filter

バンドパスフィルタ

Features

The filters exploit the interference effect of reflected light generated at the interface of a thin film to transmit desired wavelength regions. Compared with absorptive colored glass filter and gelatin filters, etc., interference filters have extremely good contrast with very narrow or sharply defined transmission bands.

Applications

Applicable to colorimeters, flame spectrometers, monochrometer, laser, optical communication, optical data storage, etc.

Effect of angle of incidence

When a filter is tilted with respect to the optical axis of the incident light, its transmission band shifts toward the shorter wavelength. At angles of incidence larger than 20 degrees, the transmission band splits into two separate peaks, because the P-component (parallel to the plane of incidence) and the S-component (perpendicular to the plane of incidence) are shifted by different amounts.

Operating temperature

The MIF type or DIF type should be used for operation for long periods up to 50deg C. It can also be used up to 80deg C for short periods. The interference filter may suffer deterioration such as change of filter characteristics depending on the operating environmental conditions. When ordering, inform us of the environmental conditions.

Required information

When you place an order, please state the required CWL, Half value width and filter size. Out of band blocking should also be specified. This can be achieved by the combination of multi-layer cut filter and color glass. So, please designate the cut off region matching to your needs corresponding to sensor sensitivity.

Specifications of an interference filter

Tmax : Maximum transmittance
Lambda 0 : Center wavelength
Lambda 0 = (Lambda 1+Lambda 2)/2
Delta 1/2 = Lambda 2-Lambda 1 : Half-width

Specifications of an BPF

A standard product

Metal-dielection interference filters : MIF=S/W type
All-dielectric interference filters : DIF-A/B/C type, DIF-BPF-1/2/3/4/5 type
Plasma ion coat band-pass filter : PIF-BPF type
Infrared interference filter : IR-BPF 0/1/2/3/4 type

Cut regions of all-dielectric interference filters and plasma ion coat band-pass filters

An interference filter is made up of a combination of several filters as shown in the figure below. Normally, a standard cut region is used unless specified otherwise. The cut region is generally determined according to the sensitivity region of the sensor. It is possible to further widen the cut region, but this reduces transmittance slightly due to loss caused by the cut filter.

MIF, DIF: Combination of several filters

Cut regions of all-dielectric interference filters and plasma ion coat band-pass filters

MIF-S type

MIF-S type

Features

This filter comprises a three-layer structure of semitransparent metal film, transparent dielectric film and semitransparent metal film formed on a glass or quartz plate with a protective cemented glass or quartz plate on it. When the optical thickness of these two kinds of metal film is half lambda of a specific wavelength or an integer multiple of such, the filter passes mostly that wavelength and blocks out other wavelengths.

MIF,DIF: Combination example data

Swipe the table below to scroll.

MIF-S type
Available wavelength range [nm] Maximum Transmittance[%] Half-width[nm] Center wavelength Tolerance [nm] Standard dimensions [mm]
Diameter Square
376-405 25-45 ≦18 ±3 15、20、
30、40、
50
50×50
406-475 30-45 ≦13 ±3
476-705 30-47 ≦13 ±3
706-955 30-45 ≦20 ±4
956-1195 28-45 ≦35 ±4
1196-1500 28-45 ≦40 ±5

MIF-W type

MIF-W type

Features

The W-type interference filter comprises 5 layers made of two S-type interference filter combination, and has the optical characteristics of narrow BPF with sharp cut-on and cut-off. Though W-type interference filter is comparatively brighter than S-type one, which means it has a broader half value width, it offers a sharper edged optical line and a greater contrast between pass band and rejection band.

Swipe the table below to scroll.

MIF-W type
Available wavelength range [nm] Maximum Transmittance [%] Half-width [nm] Center wavelength Tolerance [nm] Standard dimensions [mm]
Diameter Square
210-230 10-25 ≦20 ±3 15、20、
30、40、
50
50×50
231-260 15-25 ≦20 ±3
261-315 15-25 ≦25 ±3
316-375 15-25 ≦30 ±3
376-395 30-40 ≦25 ±3
396-455 35-48 ≦20 ±3
456-595 35-48 ≦15 ±3
596-700 35-48 ≦20 ±3

DIF-A/B/C type

DIF-A/B/C type

Features

This filter consists of dielectric multilayer films instead of MIF-S type semitransparent metal films. The Dielectric multilayer film has a higher degree of transparency, and so this filter has a narrower half-width than the MIF-S type and has higher transmittance, and can thereby sharply define the wavelength of transmitted light. All dielectric interference filters are classified as type A, B or C depending on the half-width.

Swipe the table below to scroll.

DIF-A/B/C type
Available wavelength range [nm] Standard cut region A type B type C type
Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance[%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%]
420-429 Cut up to 720nm ≧35 0.70(3.0)
430-450 ≧40 0.70(3.1) ≧35 0.45(2.0) ≧35 0.25
451-499 ≧65 0.70(3.3) ≧50 0.45(2.1) ≧40 0.21
500-549 ≧70 0.75(3.9) ≧60 0.40(2.1) ≧40 0.20
550-599 ≧75 0.80(4.6) ≧65 0.40(2.3) ≧40 0.18
600-699 ≧75 0.85(5.5) ≧70 0.45(2.9) ≧40 0.16
700-799 Cut up to(Center wavelength/0.85) ≧75 0.90(6.8) ≧70 0.50(3.8)
800-899 ≧75 0.90(7.7) ≧70 0.50(4.3)
900-999 ≧75 0.90(8.6) ≧70 0.50(4.8)
1000-1099 ≧75 0.90(9.5) ≧70 0.50(5.3)
1100-1199 ≧75 0.90(10.0) ≧70 0.50(5.8)
1200-1299 ≧75 0.90(11.0) ≧70 0.50(6.3)
1300-1399 ≧75 0.90(12.0) ≧70 0.50(6.8)
1400-1499 ≧75 0.90(13.0) ≧70 0.50(7.3)
1500-1599 ≧75 0.90(14.0) ≧70 0.50(7.8)
1600-2000 ≧65 0.90 ≧60 0.50

DIF-1/2/3/4/5 type

DIF-1/2/3/4/5 type

Features

This filter consists of dielectric multilayer films instead of MIF-W type semitransparent metal films. Since this filter provides a wider half-width than the DIF-type A/B/C, it is possible to clearly and selectively transmit a relatively wide wavelength. All dielectric interference filters are classified as type 1 to type 5 depending on the ratio of the half bandwidth to the center wavelength.

Swipe the table below to scroll.

DIF-1/2/3/4/5 type
Available wavelength range [nm] Standard cut region BPF-1 type BPF-2 type BPF-3 type BPF-4 type BPF-5 type
Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%] Maxi-mum Trans-mittance [%] Appro-ximate ratio of half width to center wave-length [%]
430-450 Cut up to 720nm ≧55 1.20(5.3) ≧55 2.30(10) ≧60 3.80(17) ≧60 7.00(31) ≧65 13.0(57)
451-499 ≧60 1.30(6.2) ≧60 2.40(11) ≧65 4.20(20) ≧65 7.50(36) ≧70 14.0(67)
500-549 ≧70 1.50(7.9) ≧70 2.50(13) ≧70 4.50(24) ≧70 8.00(42) ≧70 15.0(79)
550-599 ≧70 1.60(9.2) ≧70 2.60(15) ≧70 4.70(27) ≧70 8.50(49) ≧70 15.5(89)
600-699 ≧70 1.70(11) ≧70 2.70(18) ≧75 4.70(31) ≧75 8.50(55) ≧75 16.5(107)
700-799 ≧75 1.70(13) ≧75 2.80(21) ≧75 4.80(36) ≧75 9.00(68) ≧75 16.5(124)
800-899 Cut up to(Center wave-length/0.85) ≧75 1.70(15) ≧75 2.90(25) ≧75 4.80(41) ≧75 9.00(77) ≧75 16.5(140)
900-999 ≧75 1.70(16) ≧75 2.90(28) ≧75 5.00(48) ≧75 9.00(86) ≧75 16.5(157)
1000-1099 ≧75 1.70(18) ≧75 3.00(32) ≧75 5.00(53) ≧75 9.00(95) ≧75 16.5(173)
1100-1199 ≧75 1.70(20) ≧75 3.00(35) ≧75 5.00(58) ≧75 9.20(106)
1200-1299 ≧75 1.70(21) ≧75 3.00(38) ≧75 5.30(66) ≧75 9.20(115)
1300-1399 ≧75 1.70(23) ≧75 3.00(41) ≧75 5.30(72) ≧75 9.50(128)
1400-1499 ≧75 1.70(25) ≧75 3.00(44) ≧75 5.30(77) ≧75 9.70(141)
1500-1599 ≧75 1.70(26) ≧75 3.00(47) ≧75 5.30(82) ≧75 9.70(150)
1600-2000 ≧65 1.70 ≧65 3.00 ≧65 5.30

PIF-BPF type

PIF-BPF type

Features

The PIF-BPF is a filter manufactured using the plasma ion process and features excellent durability and environmental resistance.

PIF: Visible narrow band pass filter

PIF: Visible wide band pass filter

PIF: Near infrared wide band pass filter

PIF: Astronomical band pass filter

PIF: Astronomical band pass filter