CN108873270B - Glass-plastic mixed prime lens - Google Patents
Glass-plastic mixed prime lens Download PDFInfo
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- CN108873270B CN108873270B CN201810768667.4A CN201810768667A CN108873270B CN 108873270 B CN108873270 B CN 108873270B CN 201810768667 A CN201810768667 A CN 201810768667A CN 108873270 B CN108873270 B CN 108873270B
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- 230000003287 optical effect Effects 0.000 claims abstract description 50
- 239000011521 glass Substances 0.000 claims abstract description 14
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- 238000010586 diagram Methods 0.000 description 21
- 238000003384 imaging method Methods 0.000 description 13
- 239000000463 material Substances 0.000 description 9
- 238000012544 monitoring process Methods 0.000 description 5
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- 238000012634 optical imaging Methods 0.000 description 1
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- 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
- G02B13/0045—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 five or more lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
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- 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
- G02B13/008—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras designed for infrared light
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Abstract
The invention relates to a glass-plastic mixed fixed focus lens, which consists of a glass lens and a plastic lens, and comprises the following components: a front lens group, a diaphragm, and a rear lens group arranged in order from an object side to an image side along an optical axis; the front lens group consists of a first lens, a second lens and a third lens which are sequentially arranged from an object side to an image side along an optical axis; the rear lens group consists of a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from the object side to the image side along the optical axis; the first lens, the second lens and the fifth lens are negative focal power lenses; the third lens, the fourth lens, the sixth lens and the seventh lens are positive focal power lenses; the fourth lens and the fifth lens form a cemented lens group. The glass-plastic mixed fixed focus lens realizes high resolution under the condition that FNO is less than or equal to 2.0, gives consideration to the use performances of confocal day and night, non-deficient focus at minus 40 ℃ to 80 ℃ and the like, and expands the application range of the lens.
Description
Technical Field
The invention relates to the field of optical imaging, in particular to a glass-plastic mixed fixed-focus lens.
Background
In recent years, with the development of national economy in China, the traveling range of people is wider and wider, and the floating population is increased, so that the demands of people on security monitoring in densely populated places such as public places, residential communities, school hospitals, commercial squares and the like are higher and higher, more security monitoring lenses enter the market, and the demands of people on security monitoring are higher and higher. At present, the requirement on security monitoring lenses is mainly concentrated on all-weather work, namely day and night. In addition, in order to solve the problem of monitoring dead angles, increasing the aperture is also an important index.
The existing lens is heavy in general weight and long in total optical length, and cannot meet the requirement of miniaturization. Some lenses have reduced total optical length, but their FNO reaches only 2.0, and the cost is relatively high. In theory, the smaller the FNO is, the larger the aperture value is, the larger the luminous flux entering the optical system is, and the brightness of the image surface is higher, so that the luminous flux entering the system at night is very necessary to be improved by adopting a larger aperture for the day and night lens.
Disclosure of Invention
The invention aims to solve the problems and provides a glass-plastic mixed fixed focus lens capable of being used day and night.
In order to achieve the above object, the present invention provides a glass-plastic mixed fixed focus lens, which is composed of a glass lens and a plastic lens, comprising: a front lens group, a diaphragm, and a rear lens group arranged in order from an object side to an image side along an optical axis;
the front lens group consists of a first lens, a second lens and a third lens which are sequentially arranged from an object side to an image side along an optical axis;
the rear lens group consists of a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from the object side to the image side along the optical axis; it is characterized in that the method comprises the steps of,
the first lens, the second lens and the fifth lens are negative focal power lenses;
the third lens, the fourth lens, the sixth lens, and the seventh lens are positive power lenses.
According to one aspect of the invention, along the object-side to image-side direction,
the first lens is a convex-concave lens;
the second lens is a concave-convex lens;
the fourth lens and the fifth lens form a cemented lens group.
According to one aspect of the present invention, the first lens, the second lens, the third lens, and the seventh lens are plastic aspherical lenses;
the fourth lens, the fifth lens and the sixth lens are glass spherical lenses.
According to one aspect of the present invention, the half image height h of the lens and the effective focal length f of the lens satisfy the relation: h/f > 0.9.
According to one aspect of the present invention, the focal length f1 of the first lens, the focal length f3 of the third lens, and the focal length f6 of the sixth lens satisfy the relation: -1.80< f1/f < -1.35;4.90< f3/f <9.36;2.48< f6/f <2.90.
According to one aspect of the present invention, the combined focal length f23 of the second lens and the third lens, the combined focal length f45 of the fourth lens and the fifth lens, and the combined focal length f67 of the sixth lens and the seventh lens satisfy the relation with the effective focal length f of the lens: 4.0< f23/f <6.36;4.71< f45/f <6.16;2.20< f67/f <2.65.
According to one aspect of the present invention, the refractive index nd4 and the abbe number vd4 of the fourth lens respectively have the following value ranges: 1.40< nd4<1.65, vd4>75;
the refractive index nd5 and the abbe number vd5 of the fifth lens are respectively in the following ranges: 1.68< nd5<2.10, vd5>22.
According to one aspect of the present invention, the refractive index nd6 and the abbe number vd6 of the sixth lens respectively have the following ranges: 1.40< nd6<1.65, vd6>75.
According to one aspect of the invention, the combined optical power Ff of the front lens group and the effective focal length f of the lens barrel satisfy the relation: -4.90< ff/f < -3.45;
the combined focal power Bf of the rear lens group and the effective focal length f of the lens satisfy the relation: 1.62< Bf/f <1.94.
According to one aspect of the invention, the optical back focal length BFL of the lens and the total optical length TTL of the lens satisfy the relation: 3.0< TTL/BFL <4.0;
meanwhile, the optical total length TTL of the lens and the effective focal length f of the lens satisfy the relation: 5.40< TTL/f <7.0.
According to one aspect of the present invention, the F-number FNO of the lens is: FNO is less than or equal to 2.0.
According to one scheme of the invention, the glass-plastic mixed fixed focus lens can realize a large aperture of F1.4, ensure that an optical system of the lens has enough light flux, and even if an image surface at night still has relatively high brightness, realize day-night confocal, and realize the day-night dual-purpose function.
According to one scheme of the invention, the wave velocity mixing fixed focus lens adopts a 3G4P optical structure combining 3 glass spherical lenses and 4 plastic aspherical lenses, so that the lens can achieve a large field angle with the FOV more than or equal to 110 degrees and has a large aperture with the FNO less than or equal to 2.0 so as to ensure that the system has enough light quantity, and even though the image surface at night still has relatively high brightness.
The invention has good imaging quality through the combination of glass and plastic lenses and the matching system of the materials of the lenses, has better imaging effect under visible light, and has the same imaging effect as the visible light under the premise of not refocusing the infrared light, meanwhile, clear and bright imaging pictures are realized at night, namely, the infrared light can be imaged clearly without refocusing under the condition of clear imaging of the visible light, and day-night confocal is realized.
According to the invention, through the combination of glass and plastic lenses and the matching of the materials of the lenses, the problem that the resolution force of the lens drifts along with the temperature is effectively solved, and the lens can realize temperature compensation without virtual focus in the temperature change range of-40-80 ℃.
The invention ensures the performance and has lower cost through the optical structure of the 3G 4P; meanwhile, the length of the system is effectively reduced by using the plastic aspheric lens, so that the system is small in size and light in weight.
Drawings
FIG. 1 schematically illustrates a block diagram of a glass-plastic hybrid fixed focus lens in accordance with one embodiment of the present invention;
FIG. 2 is an MTF diagram of the glass-plastic mixed fixed focus lens in the embodiment at normal temperature of 20 ℃ and visible light;
FIG. 3 is a view of a Through-Focus-MTF of the glass-plastic mixed fixed Focus lens of the embodiment at a normal temperature of 20 ℃ and a visible light of 125 lp/mm;
FIG. 4 is a view of a Through-Focus-MTF of the glass-plastic mixed fixed Focus lens of the embodiment at room temperature of 20 ℃ and infrared at night of 125 lp/mm;
FIG. 5 is a view of a Through-Focus-MTF of the glass-plastic mixed fixed Focus lens of the embodiment at a low temperature of-40 ℃ and a visible light of 125 lp/mm;
FIG. 6 is a view of a Through-Focus-MTF of the glass-plastic mixed fixed Focus lens of the embodiment at a high temperature of 80 ℃ and a visible light of 125 lp/mm;
fig. 7 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a second embodiment of the present invention;
fig. 8 is an MTF diagram of the glass-plastic mixed fixed focus lens in the second embodiment at a normal temperature of 20 ℃ and under visible light;
FIG. 9 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens of a second embodiment at a normal temperature of 20 ℃ and a visible light of 125 lp/mm;
FIG. 10 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens of a second embodiment at room temperature of 20 ℃ and infrared at night of 125 lp/mm;
FIG. 11 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens of a second embodiment at a low temperature of-40 ℃ and a visible light of 125 lp/mm;
FIG. 12 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens of a second embodiment at a high temperature of 80 ℃ and a visible light of 125 lp/mm;
fig. 13 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a third embodiment of the present invention;
fig. 14 is an MTF diagram of the glass-plastic mixed fixed focus lens of the third embodiment at a normal temperature of 20 ℃ and under visible light;
FIG. 15 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens according to a third embodiment at a temperature of 20 ℃ and a visible light of 125 lp/mm;
FIG. 16 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens of the third embodiment at room temperature of 20 degrees and infrared at night of 125 lp/mm;
FIG. 17 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens according to a third embodiment at a low temperature of-40 ℃ and a visible light of 125 lp/mm;
FIG. 18 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens according to a third embodiment at a high temperature of 80℃and a visible light of 125 lp/mm;
fig. 19 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a fourth embodiment of the present invention;
fig. 20 is an MTF diagram of the glass-plastic mixed fixed focus lens according to the fourth embodiment at a normal temperature of 20 ℃ and under visible light;
FIG. 21 is a view of a Through-Focus-MTF of a glass-plastic mixed fixed Focus lens of a fourth embodiment at a normal temperature of 20 ℃ and a visible light of 125 lp/mm;
FIG. 22 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens according to a fourth embodiment at room temperature of 20 ℃ and infrared at night of 125 lp/mm;
FIG. 23 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens according to a fourth embodiment at a low temperature of-40 ℃ and a visible light of 125 lp/mm;
FIG. 24 is a view of a Through-Focus-MTF of a glass-plastic hybrid fixed Focus lens according to a fourth embodiment at a high temperature of 80℃and a visible light of 125 lp/mm.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in terms of orientation or positional relationship shown in the drawings for convenience of description and simplicity of description only, and do not denote or imply that the devices or elements in question must have a particular orientation, be constructed and operated in a particular orientation, so that the above terms are not to be construed as limiting the invention.
The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.
Fig. 1 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to an embodiment of the present invention. As shown in fig. 1, the glass-plastic hybrid fixed-focus lens according to the present invention includes a front lens group a, a stop S, and a rear lens group B arranged in order from an object side to an image side along an optical axis. In the present embodiment, as shown in fig. 1, the front lens group a is composed of a first lens 1, a second lens 2, and a third lens 3 arranged in order from the object side to the image side along the optical axis. The rear lens group B is composed of a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7, which are arranged in order from the object side to the image side along the optical axis. A stop S is arranged between the front lens group a and the rear lens group B, i.e. the stop S is arranged between the third lens 3 and the fourth lens 4.
In the present invention, the first lens 1, the second lens 2, and the fifth lens 5 are negative power lenses; the third lens 3, the fourth lens 4, the sixth lens 6, and the seventh lens 7 are positive power lenses. Wherein the fourth lens 4 and the fifth lens 5 constitute a cemented lens group having positive optical power.
In the present invention, the first lens 1 is a convex-concave lens along the direction from the object side to the image side; the second lens 2 is a concave-convex lens; the third lens 3 is a convex-concave lens; the fourth lens 4 is a biconvex lens; the fifth lens 5 is a concave-convex lens; the sixth lens 6 is a biconvex lens; the seventh lens 7 is a convex-concave lens.
The glass-plastic mixed fixed focus lens consists of a glass spherical lens and a plastic aspherical lens, wherein the first lens 1, the second lens 2, the third lens 3 and the seventh lens 7 are plastic aspherical lenses. The fourth lens 4, the fifth lens 5, and the sixth lens 6 are glass spherical lenses.
According to the arrangement, through the cooperation of the glass lens and the plastic lens, the total length of the lens is effectively reduced, the cost is reduced, the weight is reduced, the problem that the resolution of the lens drifts along with the temperature is effectively solved because the two materials have mutual compensation, and the lens has good resolution in the temperature change range of-40-80 ℃ and does not have virtual focus.
In addition, the half image height h of the glass-plastic mixed fixed focus lens and the effective focal length f thereof meet the relation: h/f > 0.9.
The glass-plastic mixed fixed-focus lens has a larger field angle, can achieve a large field angle with the FOV more than or equal to 110 degrees, and particularly can achieve a large field angle of 142 degrees.
In the invention, the focal length f1 of the first lens 1, the focal length f3 of the third lens 3 and the focal length f6 of the sixth lens 6 satisfy the relation: -1.80< f1/f < -1.35;4.90< f3/f <9.36;2.48< f6/f <2.90.
The glass-plastic mixed fixed-focus lens can achieve smaller field curvature and smaller CRA angle when the glass-plastic mixed fixed-focus lens has a large aperture and a large view field.
The combined focal length f23 of the second lens 2 and the third lens 3, the combined focal length f45 of the fourth lens 4 and the fifth lens 5, and the combined focal length f67 of the sixth lens 6 and the seventh lens 7 satisfy the relation: 4.0< f23/f <6.36;4.71< f45/f <6.16;2.20< f67/f <2.65.
The arrangement is favorable for optimizing and balancing the aberration on the optical axis and the aberration outside the optical axis, so that the field of view on the optical axis and the field of view outside the optical axis can reach higher imaging quality.
In the present invention, the refractive index nd4 and the abbe number vd4 of the fourth lens 4 have the following ranges: 1.40< nd4<1.65, vd4>75; the refractive index nd5 and abbe number vd5 of the fifth lens 5 have the following ranges: 1.68< nd5<2.10, vd5>22.
The arrangement is beneficial to correcting chromatic aberration of an optical system of the glass-plastic mixed fixed focus lens, and high resolution is realized.
The refractive index nd6 and abbe number vd6 of the sixth lens 6 have the following ranges: 1.40< nd6<1.65, vd6>75.
The glass-plastic mixed fixed focus lens provided by the invention has higher resolution under the working conditions of visible light and infrared light, and realizes the day-night confocal function.
In the invention, the combined focal power Ff of the front lens group A and the effective focal length f of the glass-plastic mixed fixed-focus lens meet the relation: -4.90< ff/f < -3.45;
the combined focal power Bf of the rear lens group B and the effective focal length f of the glass-plastic mixed fixed-focus lens of the invention satisfy the relation: 1.62< Bf/f <1.94.
This arrangement ensures that the lens of the present invention has a good tolerance and a small total optical length while achieving the requirements of a large aperture.
In the invention, the optical back focus BFL of the glass-plastic mixed fixed focus lens and the optical total length TTL of the glass-plastic mixed fixed focus lens meet the relation: 3.0< TTL/BFL <4.0;
meanwhile, the total optical length TTL of the glass-plastic mixed fixed focus lens and the effective focal length f of the glass-plastic mixed fixed focus lens meet the relation: 5.40< TTL/f <7.0.
This arrangement can make the optical total length of the lens of the present invention smaller and the tolerance sensitivity smaller.
In the invention, the F number FNO of the glass-plastic mixed fixed focus lens is as follows: FNO is less than or equal to 2.0.
The glass-plastic mixed fixed focus lens can realize a large aperture of F1.4, ensure that an optical system of the lens has enough light quantity, has relatively high brightness even if an image surface is at night, realizes day-night confocal, and can be used day-night.
According to the arrangement of the invention, the wave velocity mixing fixed focus lens adopts the 3G4P optical structure combining 3 glass spherical lenses and 4 plastic aspherical lenses, so that the lens can achieve a large field angle with FOV more than or equal to 110 degrees and has a large aperture with FNO less than or equal to 2.0 to ensure that the system has enough light quantity, and even if the image surface at night still has relatively high brightness.
The invention has good imaging quality through the combination of glass and plastic lenses and the matching system of the materials of the lenses, has better imaging effect under visible light, and has the same imaging effect as the visible light under the premise of not refocusing the infrared light, meanwhile, clear and bright imaging pictures are realized at night, namely, the infrared light can be imaged clearly without refocusing under the condition of clear imaging of the visible light, and day-night confocal is realized.
According to the invention, through the combination of glass and plastic lenses and the matching of the materials of the lenses, the problem that the resolution force of the lens drifts along with the temperature is effectively solved, and the lens can realize temperature compensation without virtual focus in the temperature change range of-40-80 ℃.
The invention ensures the performance and has lower cost through the optical structure of the 3G 4P; meanwhile, the length of the system is effectively reduced by using the plastic aspheric lens, so that the system is small in size and light in weight.
The following sets of embodiments are given to specifically illustrate the glass-plastic hybrid fixed focus lens according to the present invention. Because the glass-plastic mixed fixed focus lens of the invention has seven lenses, wherein the fourth lens 4 and the fifth lens 5 are glued lens groups, the seven lenses have 13 surfaces, and the total of the four surfaces of the diaphragm S, the imaging surface IMA of the lens and the flat filter IR between the imaging surface IMA and the lens is 17. The 17 faces are arranged in order according to the structural order of the present invention, and for convenience of description, the 17 faces are numbered S1 to S17. In addition, in the following embodiments, the aspherical lens satisfies the following formula:
where r is the distance from a point on the optical surface to the optical axis, z is the sagittal height of the point along the optical axis, c is the curvature of the surface, k is the conic constant of the surface, and A, B, C, D, E, F, G are the aspheric coefficients of the fourth, sixth, eighth, tenth, fourteen and sixteen orders, respectively.
Four sets of embodiment data are shown in table 1 below:
| conditional expression | Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 |
| h/f>0.9 | 0.96 | 0.96 | 1.06 | 1.19 |
| FNO≤2.0 | 2.0 | 1.4 | 1.4 | 1.4 |
| -1.80<f1/f<-1.35 | -1.40 | -1.40 | -1.62 | -1.77 |
| 4.90<f3/f<9.36 | 9.1 | 9.26 | 4.94 | 6.22 |
| 2.48<f6/f<2.90 | 2.54 | 2.58 | 2.57 | 2.80 |
| 4.0<f23/f<6.36 | 4.36 | 4.32 | 5.74 | 6.26 |
| 4.71<f45/f<6.16 | 5.33 | 5.41 | 4.77 | 5.35 |
| 2.20<f67/f<2.65 | 2.26 | 2.29 | 2.39 | 2.55 |
| -4.90<Ff/f<-3.45 | -3.5 | -4.79 | -3.66 | -4.09 |
| 1.62<Bf/f<1.94 | 1.69 | 1.71 | 1.68 | 1.84 |
| 1.40<nd4<1.65 | 1.50 | 1.50 | 1.46 | 1.44 |
| vd4>75 | 81.60 | 81.60 | 90.20 | 95.10 |
| 1.68<nd5<2.10 | 2.00 | 2.00 | 1.81 | 1.73 |
| vd5>22 | 25.44 | 25.44 | 25.48 | 28.31 |
| 1.40<nd6<1.65 | 1.50 | 1.50 | 1.46 | 1.44 |
| vd6>75 | 81.60 | 81.60 | 90.20 | 95.10 |
| 5.40<TTL/f<7.0 | 5.64 | 5.62 | 6.09 | 6.90 |
| 3.0<TTL/BFL<4.0 | 3.09 | 3.09 | 3.44 | 3.89 |
TABLE 1
Embodiment one:
the present embodiment will be described based on the lens configuration shown in fig. 1.
As the data given in embodiment 1 in table 1, the F-number fno=2.0 of the glass-plastic hybrid fixed focus lens of the present embodiment; the total optical length TTL and the optical back focal BFL meet TTL/bfl=3.09; h/f=0.96 is satisfied between the half image height h and the effective focal length f.
By the parameter setting of embodiment 1 in table 1, the glass-plastic mixed fixed focus lens of this embodiment can reach a large field angle of 115 °.
Table 2 below lists relevant parameters of each lens of the present embodiment, including surface type, radius of curvature, thickness, refractive index of material, and abbe number and cone coefficient:
TABLE 2
In this embodiment, aspherical data is shown in table 3 below:
TABLE 3 Table 3
Fig. 2 to 6 schematically show MTF diagrams of the glass-plastic hybrid fixed focus lens in the present embodiment at normal temperature of 20 degrees and under visible light, respectively; through Focus MTF graph of 125lp/mm under visible light at room temperature of 20 ℃; through Focus MTF chart of infrared light 125lp/mm at normal temperature of 20 ℃ at night; a Through-Focus-MTF diagram of 125lp/mm under visible light at a low temperature of-40 ℃; a Through-Focus-MTF plot at 80℃under visible light at 125 lp/mm.
As shown in fig. 2 to 6, the glass-plastic mixed fixed focus lens according to the first embodiment of the present invention realizes high resolution under the condition of fno=2.0, and combines the characteristics of day-night confocal and no virtual focus in the temperature range of-40 ℃ to 80 ℃, and simultaneously improves the image-capturing power, and expands the application range of products.
Specifically, as can be seen from fig. 2, the glass-plastic mixed fixed focus lens according to the first embodiment of the present invention has an OTF coefficient corresponding to a spatial frequency of 200LP/mm in its central field of view of over 0.6 under visible light, and thus it can be seen that the lens of the present embodiment achieves a high resolution characteristic.
As can be seen from fig. 3 and 4, the glass-plastic mixed fixed focus lens according to the first embodiment of the present invention has a central field of view defocus of not more than 0.01mm in both daytime and nighttime, and thus it can be seen that the lens of the present embodiment achieves characteristics of confocal day and night and no virtual focus at normal temperature.
As can be seen from fig. 5 and 6, the glass-plastic mixed fixed focus lens according to the first embodiment of the present invention has a central field-of-view defocus amount of not more than 0.002mm in a temperature range of-40 ℃ to 80 ℃, and thus it can be seen that the lens of the present embodiment achieves a characteristic of no virtual focus in a temperature range of-40 ℃ to 80 ℃.
Embodiment two:
fig. 7 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a second embodiment of the present invention. The explanation according to this embodiment is as follows:
as the data given in embodiment 2 in table 1, the F-number fno=1.4 of the glass-plastic hybrid fixed focus lens of the present embodiment; the total optical length TTL and the optical back focal BFL meet TTL/bfl=3.09; h/f=0.96 is satisfied between the half image height h and the effective focal length f.
By setting the parameters of embodiment 2 in table 1, the glass-plastic mixed fixed focus lens of this embodiment can reach a large field angle of 115 °.
Table 4 below lists relevant parameters of each lens of the present embodiment, including surface type, radius of curvature, thickness, refractive index of material, and abbe number and cone coefficient:
TABLE 4 Table 4
In this embodiment, aspherical data is shown in table 5 below:
TABLE 5
Fig. 8 to 12 schematically show MTF diagrams of the glass-plastic hybrid fixed focus lens in the present embodiment at room temperature of 20 degrees and under visible light, respectively; through Focus MTF graph of 125lp/mm under visible light at room temperature of 20 ℃; through Focus MTF chart of infrared light 125lp/mm at normal temperature of 20 ℃ at night; a Through-Focus-MTF diagram of 125lp/mm under visible light at a low temperature of-40 ℃; a Through-Focus-MTF plot at 80℃under visible light at 125 lp/mm.
As shown in fig. 8 to 12, the glass-plastic mixed fixed focus lens according to the second embodiment of the present invention realizes high resolution under the condition of fno=1.4, and combines the characteristics of day-night confocal and no virtual focus in the temperature range of-40 ℃ to 80 ℃, and simultaneously improves the image-capturing power, and expands the application range of products.
Specifically, as can be seen from fig. 8, the glass-plastic mixed fixed focus lens according to the second embodiment of the present invention has an OTF coefficient corresponding to a spatial frequency of 200LP/mm in its central field of view of 0.55 or more under visible light, and thus it can be seen that the lens of the present embodiment achieves high resolution characteristics.
As can be seen from fig. 9 and 10, the glass-plastic mixed fixed focus lens according to the second embodiment of the present invention has a central field of view defocus of not more than 0.008mm in both daytime and nighttime, and thus it can be seen that the lens of the present embodiment achieves characteristics of confocal day and night and no virtual focus at normal temperature.
As can be seen from fig. 11 and 12, the glass-plastic mixed fixed focus lens according to the second embodiment of the present invention has a central field-of-view defocus amount of not more than 0.002mm in a temperature range of-40 ℃ to 80 ℃, and thus it can be seen that the lens of the present embodiment achieves a characteristic of no virtual focus in a temperature range of-40 ℃ to 80 ℃.
Embodiment III:
fig. 13 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a third embodiment of the present invention. The explanation according to this embodiment is as follows:
as the data given in embodiment 3 in table 1, the F-number fno=1.4 of the glass-plastic hybrid fixed focus lens of the present embodiment; the total optical length TTL and the optical back focal BFL meet TTL/bfl=3.44; h/f=1.06 is satisfied between the half image height h and the effective focal length f.
Through the parameter settings of embodiment 3 in table 1, the glass-plastic mixed fixed focus lens of this embodiment can reach a large field angle of 127 °.
Table 6 below lists relevant parameters of each lens of the present embodiment, including surface type, radius of curvature, thickness, refractive index of material, and abbe number and cone coefficient:
TABLE 6
In this embodiment, aspherical data is shown in table 7 below:
TABLE 7
Fig. 14 to 18 schematically show MTF diagrams of the glass-plastic hybrid fixed focus lens in the present embodiment at room temperature of 20 degrees and under visible light, respectively; a Throughfocus MTF diagram of 125lp/mm under visible light at normal temperature of 20 ℃; through Focus MTF chart of infrared light 125lp/mm at normal temperature of 20 ℃ at night; a Through-Focus-MTF diagram of 1251p/mm under the low temperature of-40 ℃ and visible light; a Through-Focus-MTF plot at 80℃under visible light at 1251 p/mm.
As shown in fig. 14 to 18, the glass-plastic mixed fixed focus lens according to the third embodiment of the present invention realizes high resolution under the condition of fno=1.4, and combines the characteristics of day-night confocal and no virtual focus in the temperature range of-40 ℃ to 80 ℃, and simultaneously improves the image-capturing power, and expands the application range of products.
Specifically, as can be seen from fig. 14, the glass-plastic mixed fixed focus lens according to the third embodiment of the present invention has an OTF coefficient corresponding to a spatial frequency of 200LP/mm in its central field of view of 0.55 or more under visible light, and thus it can be seen that the lens of the present embodiment achieves high resolution characteristics.
As can be seen from fig. 15 and 16, the glass-plastic mixed fixed focus lens according to the third embodiment of the present invention has a central field-of-view defocus amount of not more than 0.008mm in both daytime and nighttime, and thus it can be seen that the lens of the present embodiment achieves characteristics that it can be confocal day and night and does not have a virtual focus at normal temperature.
As can be seen from fig. 17 and 18, the glass-plastic mixed fixed focus lens according to the third embodiment of the present invention has a central field-of-view defocus amount of not more than 0.002mm in a temperature range of-40 ℃ to 80 ℃, and thus it can be seen that the lens of the present embodiment achieves a characteristic of no virtual focus in a temperature range of-40 ℃ to 80 ℃.
Embodiment four:
fig. 19 schematically shows a block diagram of a glass-plastic hybrid fixed focus lens according to a fourth embodiment of the present invention. The explanation according to this embodiment is as follows:
as the data given in embodiment 4 in table 1, the F-number fno=1.4 of the glass-plastic hybrid fixed focus lens of the present embodiment;
the total optical length TTL and the optical back focus BFL meet TTL/BFL=3.89;
h/f=1.19 is satisfied between the half image height h and the effective focal length f.
By setting the parameters of embodiment 4 in table 1, the glass-plastic mixed fixed focus lens of this embodiment can reach a large field angle of 141.6 °.
Table 8 below lists relevant parameters of each lens of the present embodiment, including surface type, radius of curvature, thickness, refractive index of material, and abbe number and cone coefficient:
TABLE 8
In this embodiment, aspherical data is shown in table 9 below:
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TABLE 9
Fig. 20 to 24 schematically show MTF diagrams of the glass-plastic hybrid fixed focus lens in the present embodiment at room temperature of 20 degrees and under visible light, respectively; through Focus MTF graph of 125lp/mm under visible light at room temperature of 20 ℃; through Focus MTF chart of infrared light 125lp/mm at normal temperature of 20 ℃ at night; a Through-Focus-MTF diagram of 1251p/mm under the low temperature of-40 ℃ and visible light; a Through-Focus-MTF plot at 80℃under visible light at 1251 p/mm.
As shown in fig. 20 to 24, the glass-plastic mixed fixed focus lens according to the fourth embodiment of the present invention realizes high resolution under the condition of fno=1.4, and also combines the characteristics of day-night confocal and no virtual focus in the temperature range of-40 ℃ to 80 ℃, and simultaneously improves the image-capturing power, and expands the application range of products.
Specifically, as can be seen from fig. 20, the glass-plastic mixed fixed focus lens according to the third embodiment of the present invention has an OTF coefficient corresponding to a spatial frequency of 200LP/mm in its central field of view of 0.6 or more under visible light, and thus it can be seen that the lens of the present embodiment achieves high resolution characteristics.
As can be seen from fig. 21 and 22, the glass-plastic mixed fixed focus lens according to the fourth embodiment of the present invention has a central field-of-view defocus amount of not more than 0.006mm in both daytime and nighttime, and thus it can be seen that the lens of the present embodiment achieves characteristics that it can be confocal day and night and does not have a virtual focus at normal temperature.
As can be seen from fig. 23 and 24, the glass-plastic mixed fixed focus lens according to the fourth embodiment of the present invention has a central field-of-view defocus amount of not more than 0.005mm in a temperature range of-40 ℃ to 80 ℃, and thus it can be seen that the lens of the present embodiment achieves a characteristic of no virtual focus in a temperature range of-40 ℃ to 80 ℃.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A glass-plastic mixed fixed focus lens consists of a glass lens and a plastic lens, and comprises: a front lens group (A), a diaphragm (S) and a rear lens group (B) which are arranged in order from an object side to an image side along an optical axis;
the front lens group (A) is composed of a first lens (1), a second lens (2) and a third lens (3) which are sequentially arranged from an object side to an image side along an optical axis;
the rear lens group (B) is composed of a fourth lens (4), a fifth lens (5), a sixth lens (6) and a seventh lens (7) which are arranged in order from the object side to the image side along the optical axis; it is characterized in that the method comprises the steps of,
the first lens (1), the second lens (2) and the fifth lens (5) are negative power lenses;
the third lens (3), the fourth lens (4), the sixth lens (6) and the seventh lens (7) are positive power lenses;
the combined focal power Ff of the front lens group (a) and the effective focal length f of the lens satisfy the relation: -4.90< ff/f < -3.45;
the combined focal power Bf of the rear lens group (B) and the effective focal length f of the lens satisfy the relation: 1.62< Bf/f <1.94.
2. The glass-plastic hybrid fixed focus lens as claimed in claim 1, wherein, along the direction from the object side to the image side,
the first lens (1) is a convex-concave lens;
the second lens (2) is a concave-convex lens;
the fourth lens (4) and the fifth lens (5) form a cemented lens group.
3. The glass-plastic mixed fixed focus lens according to claim 1, wherein the first lens (1), the second lens (2), the third lens (3) and the seventh lens (7) are plastic aspherical lenses;
the fourth lens (4), the fifth lens (5) and the sixth lens (6) are glass spherical lenses.
4. A glass-plastic hybrid fixed focus lens according to any one of claims 1 to 3, wherein the half image height h of the lens and the effective focal length f of the lens satisfy the relation: h/f > 0.9.
5. A glass-plastic hybrid fixed focus lens according to one of claims 1 to 3, characterized in that the focal length f1 of the first lens (1), the focal length f3 of the third lens (3) and the focal length f6 of the sixth lens (6) satisfy the relation: -1.80< f1/f < -1.35;4.90< f3/f <9.36;2.48< f6/f <2.90.
6. A glass-plastic hybrid fixed focus lens according to one of claims 1 to 3, characterized in that the combined focal length f23 of the second lens (2) and the third lens (3), the combined focal length f45 of the fourth lens (4) and the fifth lens (5), and the combined focal length f67 of the sixth lens (6) and the seventh lens (7) satisfy the relation with the effective focal length f of the lens: 4.0< f23/f <6.36;4.71< f45/f <6.16;2.20< f67/f <2.65.
7. A glass-plastic hybrid fixed focus lens according to one of claims 1 to 3, characterized in that the refractive index nd4 and abbe number vd4 of the fourth lens (4) are respectively: 1.40< nd4<1.65, vd4>75;
the refractive index nd5 and the Abbe number vd5 of the fifth lens (5) are respectively in the following ranges: 1.68< nd5<2.10, vd5>22.
8. A glass-plastic hybrid fixed focus lens according to one of claims 1 to 3, wherein the refractive index nd6 and abbe number vd6 of the sixth lens (6) are respectively: 1.40< nd6<1.65, vd6>75.
9. A glass-plastic hybrid fixed focus lens according to any one of claims 1 to 3, wherein the optical back focus BFL of the lens and the total optical length TTL of the lens satisfy the relation: 3.0< TTL/BFL <4.0;
meanwhile, the optical total length TTL of the lens and the effective focal length f of the lens satisfy the relation: 5.40< TTL/f <7.0.
10. A glass-plastic hybrid fixed focus lens according to any one of claims 1 to 3, wherein the F-number FNO of the lens is: FNO is less than or equal to 2.0.
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| CN109557644B (en) * | 2019-01-24 | 2021-10-22 | 宁波舜宇车载光学技术有限公司 | Optical lens and imaging apparatus |
| WO2021128188A1 (en) * | 2019-12-26 | 2021-07-01 | 诚瑞光学(常州)股份有限公司 | Camera optical lens |
| CN115268014A (en) * | 2021-04-29 | 2022-11-01 | 信泰光学(深圳)有限公司 | Wide-angle lens |
| CN113138458B (en) * | 2021-04-06 | 2022-05-17 | 江西晶超光学有限公司 | Optical system, image capturing module and electronic equipment |
| CN113885167B (en) * | 2021-09-01 | 2023-02-03 | 苏州协尔智能光电有限公司 | Fixed-focus imaging system and fixed-focus imaging lens |
| TWI806454B (en) * | 2022-03-01 | 2023-06-21 | 光芒光學股份有限公司 | Fixed focus image capturing lens |
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