CN205353390U - Compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen - Google Patents
Compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen Download PDFInfo
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- CN205353390U CN205353390U CN201620023819.4U CN201620023819U CN205353390U CN 205353390 U CN205353390 U CN 205353390U CN 201620023819 U CN201620023819 U CN 201620023819U CN 205353390 U CN205353390 U CN 205353390U
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- baffle vane
- polariser
- stop ring
- light
- refrigeration detector
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Abstract
The utility model discloses a compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen, polarization type complex light stop ring group confirms interior outer diameter and mounted position including a N light stop ring, every light stop ring according to the light stop ring design principle of infrared refrigeration detector cold light door screen, and each light stop ring is formed by metal light stop ring and corresponding linear film polarizer veneer. The utility model discloses can improve its absorbility to the stray radiation on original light stop ring 's basis, restrain the rescattering that the stray radiation takes place on light stop ring, design method is simple and clear, and the structure is simple relatively, and is compatible good, can effectively improve the cold light door screen efficiency of infrared refrigeration detector, obtains higher SNR and detection sensitivity.
Description
Technical field
This utility model relates to the baffle vane group in infrared refrigeration detector cold stop, particularly to the design of the polarization-type compound baffle vane group in infrared refrigeration detector cold stop.
Background technology
Along with the development of infrared optics technology, Infrared Detectors is used in the every field in space exploration, military affairs, monitoring, medical science and daily life widely, and it is also more and more higher to the demand of sensitivity and resolution.In infrared refrigeration detector, the stray radiation of detection system is one of key factor affecting detection system actual performance.Therefore, it is suppressed that stray radiation just seems particularly significant for the infrared refrigeration detector of high accuracy.
In infrared refrigeration detector, detector focal plane arrays (FPA) element and assembly thereof are packaged in Dewar cavity.Due to detection is infra-red radiation, detector when receiving radiation, the region beyond target all can emittance, thus detector can be interfered, generally adopts, for this, the cold stop self cooled down by detector chiller.So can reduce the cold stop heat radiation to detector, detector also can be protected from the thermal-radiating impact of Dewar inwall simultaneously.Cold stop, is a significant components in Dewar.Cold stop acts primarily as the effect of restriction visual field on the one hand, reduces bias light flux, reduces background noise, thus improving the signal to noise ratio of detector chip.On the other hand, cold stop can also be effectively isolated the interference effect of infrared stray radiation and other electromagnetic radiation, thus reducing thermic load when Dewar works and can shortening the cooling activation time, improves response frequency.
By adding suitable blocking ring structure inside cold stop, it is possible to effectively suppress to enter its internal stray radiation, improve the signal to noise ratio of detector, and then promote the sensitivity of infrared refrigeration detector.Baffle vane can be used to absorb the stray radiation arriving its surface, and increases stray radiation reflection before arriving test surface or scattering imaging, and to promote its energy attenuation, it is sized and located to principle as shown in Figure 1.Blocking ring structure in practical application, far from the absorbance realized stray radiation 100%, is unfavorable for the lifting of infrared refrigeration detector signal to noise ratio, limits the application of High sensitivity infrared detector.Therefore, in order to improve the sensitivity of existing infrared refrigeration detector further, it is necessary to provide a kind of blocking ring structure and method for designing that stray radiation can be realized high-absorbility.
Summary of the invention
The purpose of this utility model is in that for the deficiencies in the prior art, the polarization-type compound baffle vane group of a kind of infrared refrigeration detector cold stop is provided, the absorbability to stray radiation of the baffle vane in infrared refrigeration detector cold stop can be improved, suppress the rescattering that stray radiation occurs on baffle vane, and then improve signal to noise ratio and the cold stop efficiency of infrared refrigeration detector.
The purpose of this utility model is achieved through the following technical solutions: the polarization-type compound baffle vane group of a kind of infrared refrigeration detector cold stop, including N number of baffle vane, according to the baffle vane design principle of infrared refrigeration detector cold stop, each baffle vane determines that inside/outside diameter size and installation site, each baffle vane include metal baffle vane and be glued at linear membrane's polariser of metal baffle vane both sides；Described linear membrane's polariser is the transmission-type plain film consistent with metal baffle vane shape, and the operation wavelength of operation wavelength and infrared refrigeration detector matches；Relative to dielectric polarizer, damage threshold and the extinction ratio of linear membrane's polariser are higher, and all band extinction ratio is more than 1000:1, and infrared band is more than 10000:1.The angle [alpha] of the light transmission shaft of each linear membrane's polariser meets following formula:
Wherein mod is remainder function, and int is bracket function, and N is the total number of baffle vane, and m is the sequence number of the baffle vane belonging to linear membrane's polariser, and m is the positive integer from 1 to N.
Further, described metal baffle vane is made up of the metal material suitable in infrared refrigeration detector, and realizes surface blackening through blasting treatment, optics blackening.
Further, at the non-cemented surface plating anti-reflection film of linear thin film polarizer to reduce surface reflection, stray radiation absorbance is increased.
Further, the side of linear membrane's polariser is ground as hair side and sprays tusche, the emittance that the side to reduce baffle vane reflects.
Further, the substrate of linear membrane's polariser is sodium silicate, and substrate thickness can be determined according to overall dimensions and Structural strength calls.The thickness of baffle vane is thin as much as possible under the premise ensureing its structural strength, and the side reflection that both can reduce baffle vane can also alleviate the overall weight of cold stop.
The beneficial effects of the utility model are:
1, the polarization absorption effect of linear membrane's polariser is utilized, can on the basis that original baffle vane absorbs, the stray radiation that efficient absorption is incident, this compound baffle vane has higher absorbance compared to common baffle vane；
2, for stray radiation that polarization state is vertical with linear membrane's polariser light transmission shaft of incident compound baffle vane, it is possible to basic realization fully absorbs；
3, the polarization transmission axis of different composite baffle vane is through design, it is possible to further enhances assimilation effect by cooperating, when scattering imaging is identical, reduces the emanated energy of stray radiation；
4, this compound baffle vane method for designing is simple and clear, and structure is relatively easy, compatible good, it is adaptable to the infrared refrigeration detector application of high sensitivity.
Accompanying drawing explanation
Fig. 1 is the baffle vane basic design method schematic diagram of infrared refrigeration detector cold stop；
Fig. 2 is baffle vane side reflection schematic diagram；
Fig. 3 is four-piece type baffle vane polariser light transmission shaft angle schematic diagram；
Fig. 4 is the relation between four-piece type baffle vane polariser light transmission shaft and baffle vane numbering；
Fig. 5 is the structural representation of the infrared refrigeration detector cold stop comprising polarization-type compound baffle vane；
Fig. 6 is described polarization-type compound baffle vane and the tradition baffle vane absorbability quantitative contrast figure to stray radiation；
In figure, 1, No. two baffle vanes of a baffle vane 2, No. three baffle vanes 3, No. four baffle vanes 4, cold stop structure 5, cold stop opening 6, detector face 7.
Detailed description of the invention
Embodiment and the design principle of efficient absorption stray radiation baffle vane in this utility model is described in detail below with reference to accompanying drawing.
The polarization-type compound baffle vane group of this utility model design is applied to the infrared refrigeration detector of high sensitivity, in order that improve the infrared refrigeration detector cold stop baffle vane absorbability to stray radiation, suppress the rescattering that stray radiation occurs on baffle vane, the cold stop efficiency of lifting system, and then improve signal to noise ratio and the detectivity of infrared refrigeration detector.
Embodiment of the present utility model is, according to the baffle vane design principle of infrared refrigeration detector cold stop, each baffle vane determines that inside/outside diameter size and installation site, each baffle vane include metal baffle vane and be glued at linear membrane's polariser of metal baffle vane both sides.
Described metal baffle vane is made up of the metal material suitable in infrared refrigeration detector and realizes surface blackening by blasting treatment, optics blackening.Baffle vane basic design principle as shown in Figure 1 determines its logical light diameter and installation site, and anchor ring external diameter is determined jointly by the cold stop bore of its installation site and infrared refrigeration detector.Below in conjunction with Fig. 1, baffle vane basic design principle is described: first determine the distance between the test surface catercorner length BD of infrared refrigeration detector and cold stop structural parameters and the two relative position and AC and BD；Connecting BM, CD, intersection point P both crossing makes to be parallel to the line segment of AC and intersects with cold stop wall contour line, is derived from size and the position of baffle vane 1；Connect the P point of A and baffle vane 1 and extend, handing over cold stop wall contour line in N, connect NB, intersect with CD, repeat the above steps, size and the position of baffle vane 2 can be obtained；By that analogy, it is possible to obtain the baffle vane that the cold stop of arbitrary shape is corresponding combines, including baffle vane quantity, the position of every baffle vane and corresponding bore, baffle vane quantity N should be determined by actual cold stop design requirement.
The thickness of baffle vane is thin as much as possible under the premise ensureing its structural strength, both can reduce the side reflection of baffle vane, it is also possible to alleviate the overall weight of cold stop.Fig. 2 gives the schematic diagram of baffle vane side reflection, α light is the light being incident normally on baffle vane, its energy major part can be absorbed by baffle vane, and β light is to the side of baffle vane, reflect usually to can be directly to via baffle vane side and corner angle and reach image planes, increase the stray radiation amount arriving image planes, it is therefore desirable to suppress.
Described linear membrane's polariser is the transmission-type plain film that light transmission shaft direction is determined, the operation wavelength of operation wavelength and infrared refrigeration detector matches, and nano-particle polarization film is with sodium silicate for substrate.Linear membrane's polariser thickness is very little, about 0.2mm.Relative to dielectric polarizer, damage threshold and the extinction ratio of linear membrane's polariser are higher, and all band extinction ratio is more than 1:1000, and infrared band is more than 1:10000.
Choose the linear membrane's polariser doubling baffle vane quantity N, demarcate light transmission shaft direction, often organize the light transmission shaft angle difference Δ γ of polariser, formula (1) determine:
Wherein N is the total number of baffle vane.The light transmission shaft that Fig. 3 describes each group of polariser for four-piece type baffle vane is distributed, a, b, c, d group polariser light transmission shaft angle respectively 0 °, 45 °, 90 °, 135 °.
Being grouped between two by the polariser demarcated, correspond respectively to each baffle vane, keep consistent with two polariser light transmission shaft directions of group, the light transmission shaft direction of each group is determined by formula (2):
Wherein mod is remainder function, and int is bracket function, and N is the total number of baffle vane, m be baffle vane numbering, for from 1 to N positive integer.Fig. 4 describes the relation between polariser light transmission shaft and baffle vane numbering for four-piece type baffle vane.
The non-cemented surface of each linear membrane's polariser is plated anti-reflection film, increases the polariser base material transmitance to incident stray radiation, reduce the secondary radiation owing to polarizer surface reflection produces.
Each group of linear membrane's polariser is cut into the shape of corresponding metal baffle vane, and side is worn into hair side, spraying tusche, to reduce the emittance of side reflection, uses optical cement by glued for the front-back of metal baffle vane corresponding for each group of polariser, notes maintenance light transmission shaft direction；Each baffle vane correspondence is fixed on by the baffle vane design principle defined location of infrared refrigeration detector, completes assembling.For the infrared refrigeration detector comprising four-piece type baffle vane, the structural representation of the infrared refrigeration detector cold stop comprising polarization-type compound baffle vane after having assembled is as it is shown in figure 5, comprise 1, No. two baffle vanes of a baffle vane 2, No. three baffle vanes 3, No. four baffle vanes 4, cold stop structure 5, cold stop opening 6, detector face 7.According to described polariser light transmission shaft distribution mode, respectively a group polariser is glued to 1 ring both sides of being in the light, c group polariser is glued to No. two baffle vane 2 both sides, and b group polariser is glued to No. three baffle vane 3 both sides, and d group polariser is glued to No. four baffle vane 4 both sides.
The following describes ultimate principle of the present utility model.Fresnel formula when reflecting at interface according to light, has formula for medium:
Formula (3) (4) sets forth incident illumination with plane of incidence vertical component (s component) and the reflectivity with plane of incidence parallel component (p-component) light intensity, n1,n2The respectively refractive index of incident medium and emergent medium, θ1,θ2Respectively angle of incidence and the angle of emergence.
For the reflection of metal surface, there is formula:
Formula (5) (6) sets forth incident illumination with plane of incidence vertical component (s component) and the reflectivity with plane of incidence parallel component (p-component) light intensity, n is the refractive index of metal, κ is the attenuation quotient of metal, θ1Respectively angle of incidence.
Be can be seen that by formula (3) (4) (5) (6), when there is reflection at medium or metal surface in light, the reflectivity of s component and p-component also differs, for degree of polarization be 0 natural light for, when it incides optical system, if when reflection occurs for optical element or structural member surface, its degree of polarization can improve accordingly.
Linear transmissive polarizer has extinction effect for incident illumination, depends on incident light polarization direction and polariser light transmission shaft angular separation θ, and extinction effect power follows the Malus' law in optical principle:
I=I0cos2θ(7)
Wherein I0For incident intensity.For natural light, when it is by polariser, output intensity can decay to the half of incident intensity, for complete polarized light, there is a specific polarizer angles, it is possible to makes it that attenuating of incident illumination to be better than the effect to natural light.Actual polarization can not the thorough delustring when θ=90 °, claim the minimum transmitted light intensity of polariser and the extinction ratio that ratio is polariser of max transmissive light intensity, extinction ratio reflects polariser and reaches the Reduction Level of light intensity during best extinction effect.
As it has been described above, when light incides optical system, owing to its degree of polarization can improve when optical element or structural member surface occur reflection to produce stray radiation or stray radiation, its light intensity just can be greatly attenuated when it is by suitable polariser.
For the polarization-type compound baffle vane in this utility model, mainly comprehensively realize delustring in the following areas:
1. the stray radiation inciding polariser can decay light intensity due to polarization extinction effect, and the polarization state of emergent light is the line polarisation parallel with polariser light transmission shaft；
2. can absorb the stray radiation transmitted through polariser through traditional baffle vane of sandblasting and optics blackening process；
3. change further through the stray radiation polarization state of baffle vane reflection, to be different from the angle outgoing with a piece of polariser light transmission shaft, again realize polarization extinction and with new linear polarization outgoing；
If 4. the stray radiation of the special angle linear polarization of outgoing incides other baffle vane, owing to the polariser light transmission shaft direction of each baffle vane is different and coincidence formula (2) distribution, it will this stray radiation is had good inhibition；
5. incident stray radiation is also had absorption effect by polarizer material.
The most desired effect of described in the utility model baffle vane is exemplified below: if stray radiation is incident with the polarization state of approximate nature light, if its light intensity is I0, linear polarization is 90 °, when it incides the baffle vane that first light transmission shaft direction is 0 °, if the extinction ratio of baffle vane is 1:10000, then light intensity I1=0.5I0；If the absorbance of the material on incident infrared light of polariser is 2%, the absorbance of baffle vane is 90%, then the light intensity from baffle vane reflection is I2=0.049I0；Can calculate the polarization state change of reflection light according to Fresnel formula (3) (4), approximate setting reflects light polarization main shaft with polariser light transmission shaft angle as 5 °, then output intensity I3=0.98*0.049*cos2(5°)*I0≈0.047I0, when this stray radiation enters another vertical with its polarization direction compound baffle vane, output intensity is I4=0.047*10-5*0.98*0.1*0.98*cos2(5°)*I0=4.48*10-8I0.The absorbability of this utility model and tradition baffle vane contrasts as shown in Figure 6.This utility model combines polarization absorption, transmission material absorbs and three kinds of principles of absorption of tradition baffle vane, even if the stray radiation polarization state in practical situation is different, overall absorption effect is still significantly stronger than the assimilation effect of tradition baffle vane, for highly sensitive Infrared Detectors application tool significance.
Claims (3)
1. the polarization-type compound baffle vane group of one kind infrared refrigeration detector cold stop, including N number of baffle vane, each baffle vane determines inside/outside diameter size and installation site according to the baffle vane design principle of infrared refrigeration detector cold stop, it is characterized in that, each baffle vane includes metal baffle vane and is glued at linear membrane's polariser of metal baffle vane both sides；Described linear membrane's polariser is the transmission-type plain film consistent with metal baffle vane shape, and the operation wavelength of operation wavelength and infrared refrigeration detector matches；The angle [alpha] of the light transmission shaft of each linear membrane's polariser meets following formula:
Wherein mod is remainder function, and int is bracket function, and N is the total number of baffle vane, and m is the sequence number of the baffle vane belonging to linear membrane's polariser, and m is the positive integer from 1 to N.
2. the polarization-type compound baffle vane group of a kind of infrared refrigeration detector cold stop according to claim 1, it is characterised in that the non-cemented surface plating anti-reflection film of described linear membrane's polariser.
3. the polarization-type compound baffle vane group of a kind of infrared refrigeration detector cold stop according to claim 1, it is characterised in that the side mill of described linear membrane's polariser for hair side and sprays tusche.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620023819.4U CN205353390U (en) | 2016-01-11 | 2016-01-11 | Compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620023819.4U CN205353390U (en) | 2016-01-11 | 2016-01-11 | Compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen |
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| CN205353390U true CN205353390U (en) | 2016-06-29 |
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| CN201620023819.4U Withdrawn - After Issue CN205353390U (en) | 2016-01-11 | 2016-01-11 | Compound light stop ring group of polarization type of infrared refrigeration detector cold light door screen |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105487149A (en) * | 2016-01-11 | 2016-04-13 | 浙江大学 | Polarization type composite light blocking ring group of cold stop of infrared refrigeration detector and manufacturing method |
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2016
- 2016-01-11 CN CN201620023819.4U patent/CN205353390U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105487149A (en) * | 2016-01-11 | 2016-04-13 | 浙江大学 | Polarization type composite light blocking ring group of cold stop of infrared refrigeration detector and manufacturing method |
| CN105487149B (en) * | 2016-01-11 | 2017-10-27 | 浙江大学 | The polarization-type of infrared refrigeration detector cold stop compound be in the light ring group and preparation method |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160629 Effective date of abandoning: 20171027 |