Filter set, fluorescence observation system and method for simultaneously observing fluorescent and non-fluorescent regions of an object
The present invention relates to a filter set, to a fluorescence observation system and to a method for simultaneously observing fluorescent and non-fluorescent regions of an object. The filter set comprises an illumination filter and an observation filter. The illumination filter is configured such that it efficiently transmits visible light having short wavelengths and efficiently blocks light having a long wavelength. The observation filter is configured such that it efficiently blocks visible light having short wavelengths and efficiently transmits light having a long wavelength. The illumination filter and the observation filter are configured such that the product of the transmittance of the illumination filter T I (λ) and the transmittance of the observation filter T O (λ) are very constant over a high proportion of the visible wavelength range.
1 . Filter set for simultaneously observing fluorescent and non-fluorescent regions of an object, comprising:
an illumination filter and an observation filter;
wherein the average value of T I (λ) over a first wavelength range from a wavelength λ VIS,MIN up to a wavelength λ 1 is greater than a first value W1;
wherein the average value of T I (λ) over a second wavelength range from a wavelength λ 2 up to a wavelength λ VIS,MAX is smaller than a second value W2;
wherein the average value of T O (λ) over the first wavelength range is smaller than the second value W2;
wherein the average value of T O (λ) over the second wavelength range is greater than the first value W1;
wherein the average value of
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10
(
T
I
(
λ
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·
T
O
(
λ
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µ
WLB
3
)
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over a third wavelength range, which is a union of the first and the second wavelength ranges, is smaller than a third value W3 so that the object is observable with the color fidelity, wherein μ WLB3 is the average of T I (λ)·T O (λ) over the third wavelength range;
wherein T I (λ) is the wavelength-dependent transmittance of the illumination filter,
wherein T O (λ) is the wavelength-dependent transmittance of the observation filter;
wherein λ VIS,MIN <λ 1 <λ 2 <λ VIS,MAX , λ VIS,MIN =380 nm and λ VIS,MAX =780 nm;
wherein W1>100·W2;
wherein W3<1.5;
wherein μ WLB3 >K1·μ WLB4 with K1=10, is the average value of T I (λ)·T O (λ) over a fourth wavelength range from the wavelength λ 1 up to the wavelength λ 2 .
2 . Filter set according to claim 1 , wherein W3<1.0.
3 . Filter set according to claim 1 , wherein
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≤
W
4
for each wavelength λ within the third wavelength range with W4=1.5.
4 . Filter set according to claim 1 , wherein μ WLB3 >0.00001; and/or wherein μ WLB3 >0.01.
5 . Filter set according to claim 1 , wherein |λ 1 −λ 2 |≤100 nm; and/or wherein |λ 1 −λ 2 |≥10 nm.
6 . Filter set according to claim 1 , wherein
K2·μ WLB3 >T I (λ)· T O (λ)
for each wavelength λ within a fifth wavelength range from the wavelength λ 1 up to the wavelength λ 2 with K2=1.5.
7 . Filter set according to claim 1 , wherein W1>200·W2.
8 . Filter set according to claim 1 , wherein W1≥0.1; and/or wherein W2≤0.05.
9 . Filter set according to claim 1 , wherein the use of the filter set for protoporphyrin IX;
400 nm≤λ 1 ≤650 nm and λ 2 ≤650 nm.
10 . Filter set according to claim 1 , wherein for us of the filter set for fluorescein:
450 nm≤λ 1 ≤510 nm and λ 2 ≤530 nm.
11 . Fluorescence observation system for simultaneously observing fluorescent and non-fluorescent regions of an object, comprising:
an illumination system having a light source for illuminating the object;
an observation system for imaging the object; and
a filter set comprising an illumination filter and an observation filter,
wherein the average value of T I (λ) over a first wavelength range from a wavelength λ VIS,MAX up to a wavelength λ 1 is greater than a first value W1;
wherein the average value of T I (λ) over a second wavelength range from a wavelength λ 2 up to a wavelength λ VIS,MAX is smaller than a second value W2;
wherein the average value of T O (λ) over the first wavelength range is smaller than the second value W2;
wherein the average value of T O (λ) over the second wavelength range is greater than the first value W1;
wherein the average value of
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"\[LeftBracketingBar]"
log
10
(
T
I
(
λ
)
·
T
O
(
λ
)
μ
WLB
3
)
❘
"\[RightBracketingBar]"
over a third wavelength range, which is a union of the first and the second wavelength ranges, is smaller than a third value W3 so that the object is observable with color fidelity, wherein μ WLB3 is the average value of T I (λ)·T O (λ) over the third wavelength range;
wherein T I (λ) is the wavelength-dependent transmittance of the illumination filter,
wherein T O (λ) is the wavelength-dependent transmittance of the observation filter;
wherein λ VIS,MIN <λ 1 <λ 2 <λ VIS,MAX , λ VIS,MIN =380 nm and λ VIS,MAX =780 nm;
wherein W1>100·W2;
wherein W3<1.5;
wherein μ WLB3 >K1·μ WLB4 with K1=10, wherein μ WLB4 is the average value of T I (λ)·T O (λ) over a fourth wavelength range from the wavelength λ 1 up to the wavelength λ 2 ; and
wherein the illumination filter of the filter set is arranged in an illumination beam path between the light source and the object and the observation filter of the filter set is arranged in an observation beam path of the observation system.
12 . Method for simultaneously observing fluorescent and non-fluorescent regions of an object using a filter set, wherein the method comprises:
filtering an illumination light beam, which is directed onto the object, using an illumination filter of the filter set; and
filtering light emanating from the object using an observation filter of the filter set,
wherein the average value of T I (λ) over a first wavelength range from a wavelength λ VIS,MIN up to a wavelength λ 1 is greater than a first value W1;
wherein the average value of T I (λ) over a second wavelength range from a wavelength λ 2 up to a wavelength λ VIS,MAX is smaller than a second value W2;
wherein the average value of T O (λ) over the first wavelength range is smaller than the second value W2;
wherein the average value of T O (λ) over the second wavelength range is greater than the first value W1;
wherein the average value of
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"\[LeftBracketingBar]"
log
10
(
T
I
(
λ
)
·
T
O
(
λ
)
μ
WLB
3
)
❘
"\[RightBracketingBar]"
over a third wavelength range, which is a union of the first and the second wavelength ranges, is smaller than a third value W3 so that the object is observable with color fidelity, wherein μ WLB3 is the average value of T I (λ)·T O (λ) over the third wavelength range;
wherein T I (λ) is the wavelength-dependent transmittance of the illumination filter,
wherein T O (λ) is the wavelength-dependent transmittance of the observation filter;
wherein λ VIS,MIN <λ 1 <λ 2 <λ VIS,MAX , λ VIS,MIN =380 nm and λ VIS,MAX =780 nm;
wherein W1>100·W2;
wherein W3<1.5; and
wherein μ WLB3 >K1·μ WLB4 with K1=10, wherein μ WLB4 is the average value of T I (λ)·T O (λ) over a fourth wavelength range from the wavelength λ 1 up to the wavelength λ 2 .