NL2030343B1 - Infrared thermal imaging optical system - Google Patents
Infrared thermal imaging optical system Download PDFInfo
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- NL2030343B1 NL2030343B1 NL2030343A NL2030343A NL2030343B1 NL 2030343 B1 NL2030343 B1 NL 2030343B1 NL 2030343 A NL2030343 A NL 2030343A NL 2030343 A NL2030343 A NL 2030343A NL 2030343 B1 NL2030343 B1 NL 2030343B1
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- Prior art keywords
- optical system
- infrared thermal
- thermal imaging
- lens
- infrared heat
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- 230000003287 optical effect Effects 0.000 title claims abstract description 120
- 238000001931 thermography Methods 0.000 title abstract description 49
- 239000000463 material Substances 0.000 claims description 13
- 239000005387 chalcogenide glass Substances 0.000 claims description 3
- 239000002178 crystalline material Substances 0.000 claims description 3
- SBIBMFFZSBJNJF-UHFFFAOYSA-N selenium;zinc Chemical compound [Se]=[Zn] SBIBMFFZSBJNJF-UHFFFAOYSA-N 0.000 claims description 3
- 238000003384 imaging method Methods 0.000 abstract description 32
- 230000005499 meniscus Effects 0.000 abstract description 15
- 238000013461 design Methods 0.000 abstract description 13
- 238000005286 illumination Methods 0.000 abstract description 13
- 238000005516 engineering process Methods 0.000 abstract description 6
- 230000003321 amplification Effects 0.000 abstract description 4
- 238000009529 body temperature measurement Methods 0.000 abstract description 4
- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 4
- 230000000007 visual effect Effects 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 238000012546 transfer Methods 0.000 description 7
- 230000008901 benefit Effects 0.000 description 3
- 230000036760 body temperature Effects 0.000 description 3
- 230000036541 health Effects 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 206010010071 Coma Diseases 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000003331 infrared imaging Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012634 optical imaging Methods 0.000 description 1
- 238000010827 pathological analysis Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/14—Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0075—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/01—Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J2005/0077—Imaging
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/02—Constructional details
- G01J5/08—Optical arrangements
- G01J5/0806—Focusing or collimating elements, e.g. lenses or concave mirrors
Abstract
The present invention provides an infrared thermal imaging optical system, comprising a negative meniscus lens L1, a positive biconveX lens L2, a diaphragm S, a negative biconcave lens L3, and a positive biconveX lens L4 in sequence from an object plane to an image plane along an optical axis, the reciprocal of the angular amplification of the negative meniscus lens L1 to the off-axis principal ray 1/7 satisfies: 1.5 51/7524. The present invention also provides the use of an infrared thermal imaging optical system in the medical field. The infrared thermal imaging optical system realizes an optical system design with a large relative aperture, a large field of view and high illumination uniformity, and not only has a high spatial resolution imaging capability, but also has a capability of realizing low-noise equivalent temperature difference and large imaging visual field, so as to satisfy the temperature measurement requirement of the infrared thermal imaging equipment on the high-performance infrared optical system, which is beneficial for wide application and promotion in medical technology.
Description
INFRARED THERMAL IMAGING OPTICAL SYSTEM
[01] The present invention relates to the field of optical technology, and more specifically, to an infrared thermal imaging optical system.
[02] With the improvement of human living standards and more attention to health, infrared thermal imaging technology can play the role of early prevention and early detection, and play an important role in medical health examination and pathological diagnosis. Primarily limited by the insufficient technical development of the optical system, the current infrared thermal imaging system is not high in temperature resolution or spatial resolution, and is difficult to realize the precise measurement and identification of the human body temperature field, which is not conducive to in-depth study of the correlation mechanism between human body heat distribution and health and establishment of a physical model for precise 1dentification.
[03] Infrared thermal imaging technology has great development space and broad prospects in the medical field. The infrared thermal imaging device realizes the precise analysis of the thermal structure of the human body by measuring the temperature difference, and the adopted infrared thermal imaging optical system is different from the commonly used infrared optical system due to the limitation by the application environment. The infrared thermal imaging device has high requirements on the optical system, and not only has a high spatial resolution imaging capability, but also has a capability of realizing low-noise equivalent temperature difference and large imaging visual field. The infrared optical systems in current thermal imaging devices are difficult to meet both of these requirements.
[04] The object of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide an infrared thermal imaging optical system, wherein the infrared thermal imaging optical system realizes an optical system design with a large relative aperture, a large field of view and high illumination uniformity, and not only has a high spatial resolution imaging capability, but also has a capability of realizing low-noise equivalent temperature difference and large imaging visual field, so as to satisfy the temperature measurement requirement of the infrared thermal imaging equipment on the high-performance infrared optical system, which is beneficial for wide application and promotion in medical technology.
[05] In order to achieve the above object, the present invention is achieved by the following technical solution: an infrared thermal imaging optical system is characterized by: from the object plane to the image plane along the optical axis, comprising a negative meniscus lens L1, a positive biconvex lens L2, a diaphragm S, a negative biconcave lens L3, and a positive biconvex lens L4 in sequence;
[06] the reciprocal of the angular amplification of the negative meniscus lens L1 to the off-axis principal ray 1/y satisfies:
[07] 1.5<1/y<2.4.
[08] In the above-described technical solution, the diaphragm S between the positive biconvex lens L2 and the negative biconcave lens L3 of the present invention is an aperture diaphragm S. In addition, the surface types of the negative meniscus lens L1, the positive biconvex lens L2, the negative biconcave lens L3 and the positive biconvex lens L4 are all spherical or aspherical. Setting the reciprocal of the angular amplification of the negative meniscus lens L1 to the off-axis principal ray 1/v can greatly reduce the distorted high-order aberration of the large-angle incident ray entering the infrared thermal imaging optical system, thereby further improving the spatial resolution imaging capability.
[09] The optical power of the negative meniscus lens L1 (®L1) and the optical power of the infrared thermal imaging optical system (¢) satisfy the following relationship:
[10] -0.35<@L1/p<-0.25.
[11] The optical power of the positive biconvex lens L2 (®L2) and the optical power of the infrared thermal imaging optical system (9) satisfy the following relationship:
[12] 0.4059L2/9=0.55.
[13] The optical power of the negative biconcave lens L3 (®L3) and the optical power of the infrared thermal imaging optical system (9) satisfy the following relationship:
[14] -0.75<9L3/9=-0.60.
[15] The optical power of the positive biconvex lens L4 (®L4) and the optical power of the infrared thermal imaging optical system (9) satisfies the following relationship:
[16] 0.90<9L4/951.05.
[17] The materials of the negative meniscus lens L 1, negative biconcave lens L3 and positive biconvex lens L4 are all chalcogenide glass materials IG2, IG4 or IG6;
[18] the material of the negative biconcave lens L3 is a crystalline material ZnS or
ZnSe.
[19] The aperture F# of the infrared thermal imaging optical system is between 0.9 and 1.2; the imaging object distance range of infrared thermal imaging optical system is 1-3 m.
[20] The structural material of the infrared thermal imaging optical system of the present invention is an aluminium alloy; in order to work stably in different temperature environments, a passive athermalization design is achieved, and the distance between the infrared thermal imaging optical system and a non-refrigerated infrared detector does not need to be changed at different temperatures, so as to ensure clear imaging, thus satisfying the above relationship.
[21] In addition, in the present invention, in order to improve the energy consistency of different field of view targets on a uncooled infrared detector, the image space achieves the design of a near telecentric optical path, with telecentricity controlled within 3.5°, by introducing the diaphragm coma through the design, the illumination distribution on the image plane is improved from being proportional to the fourth power of the field of view angle cosine in the prior art to being superior to being proportional to the first power of the field of view angle cosine, and the illumination uniformity is greatly improved.
[22] The advantages of the infrared thermal imaging optical system of the present invention are as follows:
[23] 1) the infrared thermal imaging optical system has a large imaging field of view, and can realize thermal imaging covering the whole human body at a short distance without scanning in medical applications;
[24] 2) the whole-field illumination uniformity of the infrared thermal imaging optical system is better than 90%, which ensures high edge illumination;
[25] 3) imaging resolution is high, suitable for large target surface infrared detector with 640 * 512, 17 um;
[26] 4) the distortion is small, and the full field distortion is less than 2%.
[27] Compared with the prior art, the present invention has the following advantages and benefits: the infrared thermal imaging optical system realizes an optical system design with a large relative aperture, a large field of view and high illumination uniformity, and not only has a high spatial resolution imaging capability, but also has a capability of realizing low-noise equivalent temperature difference and large imaging visual field, so as to satisfy the temperature measurement requirement of the infrared thermal imaging equipment on the high-performance infrared optical system, which is beneficial for wide application and promotion in medical technology.
[28] FIG. 1 is a schematic structural diagram of an optical system of the present invention;
[29] FIG. 2 is a graph showing the optical transfer function of the optical system of the present invention with an imaging object distance of 1 m;
[30] FIG. 3 is a graph showing the optical transfer function of the optical system of the present invention with an imaging object distance of 1.5 m;
[31] FIG. 4 is a graph showing the optical transfer function of the optical system of the present invention with an imaging object distance of 3 m;
[32] FIG. 5 is a graph showing illumination uniformity distribution of the optical system of the present invention;
[33] FIG. 6 is a graph showing distortion distribution of the optical system of the 5 present invention.
[34] The present invention is further described in detail below with reference to accompanying drawings and specific examples.
[35] Example
[36] As shown in FIGS. 1 to 6, the infrared thermal imaging optical system of the present invention comprises negative meniscus lens L1, a positive biconvex lens L2, a diaphragm S, a negative biconcave lens L3, and a positive biconvex lens L4 in sequence from the object plane to the image plane along the optical axis. Wherein an aperture diaphragm S is provided between the positive biconvex lens L2 and the negative biconcave lens L3. In addition, the surface types of the negative meniscus lens L1, the positive biconvex lens L2, the negative biconcave lens L3 and the positive biconvex lens L4 are all spherical or aspherical. In order to reduce the distorted high-order aberration generated by the large-angle incident ray entering the optical system, the reciprocal of the angular amplification of the negative meniscus lens L1 to the off-axis principal ray 1/y satisfies:
[37] 1.55124.
[38] Specifically, the optical power of the negative meniscus lens L1 (®L1) and the optical power of the infrared thermal imaging optical system (9) satisfy the following relationship:
[39] -0.35<¢L1/p<-0.25.
[40] The optical power of the positive biconvex lens L2 (®L2) and the optical power of the infrared thermal imaging optical system (9) satisfy the following relationship:
[41] 0.4059L2/9=<0.55.
[42] The optical power of the negative biconcave lens L3 (®L3) and the optical power of the infrared thermal imaging optical system (9) satisfy the following relationship:
[43] -0.75<@L3/9<-0.60.
[44] The optical power of the positive biconvex lens L4 (®L4) and the optical power of the infrared thermal imaging optical system (9) satisfies the following relationship:
[45] 0.90<¢L4/¢<1.05.
[46] The materials of the negative meniscus lens L1, negative biconcave lens L3 and positive biconvex lens L4 of the present invention are all chalcogenide glass materials 1G2, IG4 or 1G6; and the material of the negative biconcave lens L3 is a crystalline material ZnS or ZnSe.
[47] The aperture F# of the infrared thermal imaging optical system is between 0.9 and 1.2; the imaging object distance range of infrared thermal imaging optical system is 1-3 m.
[48] The optical parameters of the optical system of this Example are shown in the following table.
[49]
Surface | Name Radius of | Interval Materials | Clear
No. curvature mm aperture mm 1 Negative meniscus | 57.79785 9.81 IG6 ®46.1 lens L1
EE mew we [wee 3 Positive biconvex | 34.74925 8.02 1G6 ®21.9 lens L2
CL eww wm | wer oes ees | less 6 Negative -28.09258 4.45 ZnS 15.6 biconcave lens L3
ET aes fw | em
Positive biconvex | 22.75205 7.98 IG6 020.5 lens L4 oo -46.28936 9.52 ©20.4 0 Jie 2 [| Jew
[50] In the examples of the present invention, front and rear surfaces of the negative meniscus lens L1 ( S1, S2), the front and rear surfaces of the positive biconvex lens L2 ( S3, S4), and the front and rear surfaces of the positive biconvex lens L4 ( S7, S8) are aspherical surfaces satisfying the following formula:
Z(r)= en + Ar’ + Br° + Cr® + Dr" s [SI] 1+1-(1 +k)?
[52] In the formula, Z is a distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis; C = 1/R, R represents the paraxial radius of curvature of the mirror surface; K is a cone coefficient;
A, B, C and D are high order aspheric coefficients, and the aspheric coefficients are shown in the following table:
[53] kh EEE
Sf EEN
Ee OE EE ee rooms asen [z enen [even seen [ea [seen
[54] In the examples of the present invention, the optical system composed of the above lenses achieves the following technical indexes: (1) Operating band: 8-13 pm; (2)
Focal length: 8.5 mm; (3) Field of view: 80° (4) Detector: 640*512, 17 um; (5)
Relative aperture: F#/1.1; (6) Distortion: not more than 2%; (7) Illumination uniformity: not less than 90%.
[55] The applications of the infrared thermal imaging optical system of the present invention in the medical field are as follows: the infrared thermal imaging optical system is an optical imaging device for medical infrared thermal imaging, which can realize the whole body temperature field imaging in close range and collect the whole body temperature field information.
[56] The infrared thermal imaging optical system has a large field of view imaging capability, and the focal length of the optical system is set as f, the diagonal length of the uncooled infrared detector is set as H, and the field angle is set aso, satisfying:
[57] = 360° x arctan (£) JE: w = 80°
[58]
[59] When the infrared thermal imaging optical system is used for photographing a thermal image of a human body, the optical system is cooperated with an uncooled infrared detector of 640 * 512 and 17 um; the array direction of 640 corresponds to to a vertical direction and the array direction of 512 corresponding to a horizontal direction, and the imaging range under different imaging distances satisfies:
[60]
Serial Imaging distance | Vertical imaging width | Horizontal imaging width number (m) (m) (m)
[61] In order to improve the energy consistency of different field of view targets on a uncooled infrared detector, the image space achieves the design of a near telecentric optical path, with telecentricity controlled within 3.5°, by introducing the diaphragm coma through the design, the illumination distribution on the image plane is improved from being proportional to the fourth power of the field of view angle cosine in the prior art to being superior to being proportional to the first power of the field of view angle cosine, and the illumination uniformity is greatly improved.
[62] The structural material of the infrared thermal imaging optical system of the present invention is an aluminium alloy; in order to work stably in different temperature environments, a passive athermalization design is achieved, and the distance between the infrared thermal imaging optical system and a non-refrigerated infrared detector does not need to be changed at different temperatures, so as to ensure clear imaging; the optical power of the infrared thermal optical system is set as ©, ©; is the optical power of the ith lens, hi is the radial height of the first paraxial ray on the incident surface of the ith lens, x; is the athermalization coefficient of the ith lens, ax is the linear expansion system of the structural material of the optical system, and L is the length of the lens cone of the optical system, satisfying:
[63] 5 Shiv, = gl.
[64] In the examples of the present invention, the imaging field of view of the optical system reaches more than 80°, and the imaging range of 1.92 m in height and 1.53 m in width can be realized at an object distance of 1.5 m, so as to realize one-time imaging of the whole body surface of the human body, avoiding the problem that an infrared thermal imaging device needs scanning imaging to cover the whole body imaging of the human body. In the examples of the present invention, the optical system may be used in infrared thermal imaging devices in the medical field by cooperating with an uncooled infrared detector, to realize infrared imaging, and be used for tasks such as temperature measurement.
[65] FIGS. 2-4 characterize the optical transfer function curve distribution of an optical system of an example of the present invention at different imaging object distances. FIG. 2 shows the design results at an object distance of 1 m, with an average optical transfer function value of 0.5@30 1p/mm; FIG. 3 shows the design results at an object distance of 1.5 m, with an average optical transfer function value of 0.51@30
Ip/mm; FIG. 4 shows the design results at an object distance of 3 m, with an average optical transfer function value of 0.49@30 lp/mm, which has excellent imaging quality.
[66] FIG. 5 characterizes the illumination uniformity characterize of an optical system in an example of the present invention, with an illumination uniformity better than 90% over the full field of view.
[67] FIG. 6 characterizes the distortion design curve distribution of an optical system in an example of the present invention, with an relative distortion of the full field of view not more than 2%.
[68] The foregoing embodiments are preferred embodiments of the present invention.
However, the embodiments of the present invention are not limited by the foregoing embodiments. Any other changes, modifications, replacements, combinations and simplifications made without departing from the spirit and principle of the present invention should all be equivalent replacement manners, and fall within the protection scope of the present invention.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2030343A NL2030343B1 (en) | 2021-12-29 | 2021-12-29 | Infrared thermal imaging optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2030343A NL2030343B1 (en) | 2021-12-29 | 2021-12-29 | Infrared thermal imaging optical system |
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| Publication Number | Publication Date |
|---|---|
| NL2030343B1 true NL2030343B1 (en) | 2023-07-04 |
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ID=87202384
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2030343A NL2030343B1 (en) | 2021-12-29 | 2021-12-29 | Infrared thermal imaging optical system |
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| Country | Link |
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| NL (1) | NL2030343B1 (en) |
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2021
- 2021-12-29 NL NL2030343A patent/NL2030343B1/en active
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