CN117555116B - Optical lens and camera module - Google Patents
Optical lens and camera module Download PDFInfo
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- CN117555116B CN117555116B CN202311846740.2A CN202311846740A CN117555116B CN 117555116 B CN117555116 B CN 117555116B CN 202311846740 A CN202311846740 A CN 202311846740A CN 117555116 B CN117555116 B CN 117555116B
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- 230000003287 optical effect Effects 0.000 title claims abstract description 175
- 239000000758 substrate Substances 0.000 claims abstract description 77
- 238000003384 imaging method Methods 0.000 claims abstract description 50
- 239000011521 glass Substances 0.000 claims abstract description 9
- 238000004026 adhesive bonding Methods 0.000 claims abstract description 8
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Classifications
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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
-
- 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
- G02B13/0035—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 three lenses
-
- 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
- G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
- G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
- G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
- G02B23/2407—Optical details
- G02B23/2415—Stereoscopic endoscopes
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
- G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
- G02B23/2407—Optical details
- G02B23/2423—Optical details of the distal end
- G02B23/243—Objectives for endoscopes
Abstract
The invention discloses an optical lens and a camera module, which sequentially comprise a first group, a second group and protective glass from an object side to an imaging surface along an optical axis; the first group has negative focal power, and consists of a first lens and a first substrate which are connected in a gluing way in sequence from the object side to the imaging surface along the optical axis, wherein the first lens has negative focal power; the second group has positive focal power and consists of a second lens, a second substrate and a third lens which are connected in sequence from the object side to the imaging surface along the optical axis; the third lens has positive optical power; and the object side surface or the image side surface of the first substrate or the second substrate is plated with a diaphragm. The optical lens provided by the invention reduces the size and caliber of the lens while meeting the requirement of a large field angle, effectively increases the depth of field of the lens, and can well meet the requirements of the detection range and the observation depth of an endoscope.
Description
Technical Field
The present invention relates to the field of optical imaging technology, and in particular, to an optical lens and an imaging module.
Background
In recent years, with the rapid development of the medical field, the requirements of society on medical equipment are increasing, and in particular, the requirements on the performance of cameras mounted on medical detection equipment are increasing, for example, in order to more flexibly and comprehensively enter a human body to collect images, medical equipment such as an endoscope and the like carrying an imaging lens is generally adopted to perform the examination of various intracavity diseases such as gastrointestinal tract, pancreas, biliary tract, respiratory tract and the like so as to determine the internal structure of the human body or observe pathological states.
Currently, in the market, endoscope lenses generally have problems of oversized size, small angle of view and insufficient depth of field, such as: the oversized endoscope can cause discomfort to a human body when the endoscope is used, the small angle of view can cause the scope of observation of the endoscope lens to be insufficient, and the small depth of field can influence the depth of observation of the endoscope lens.
Disclosure of Invention
Therefore, the invention aims to provide an optical lens and an imaging module, which at least have the characteristics of small size, small caliber, large field of view and large depth of field.
The embodiment of the invention realizes the aim through the following technical scheme.
In one aspect, the present invention provides an optical lens, which sequentially comprises a first group, a second group, and a protective glass from an object side to an imaging surface along an optical axis; the first group has negative focal power, and consists of a first lens and a first substrate which are connected in a gluing way in sequence from the object side to the imaging surface along the optical axis, wherein the first lens has negative focal power; the second group has positive focal power and consists of a second lens, a second substrate and a third lens which are connected in sequence from the object side to the imaging surface along the optical axis; the third lens has positive optical power; a diaphragm is plated on the object side surface or the image side surface of the first substrate or the second substrate; wherein, the optical lens satisfies the conditional expression: 0.09< F/f# <0.12, -8< F1/F3< -0.5, F represents an effective focal length of the optical lens, f# represents an aperture value of the optical lens, F1 represents an effective focal length of the first lens, and F3 represents an effective focal length of the third lens.
In some embodiments, the means for glue bonding includes nano-imprinting means or etching means.
In some embodiments, the optical lens satisfies the following conditional expression: 0.5< f/H <0.65, wherein f represents the effective focal length of the optical lens, and H represents the image height corresponding to the maximum field angle of the optical lens.
In some embodiments, the optical lens satisfies the following conditional expression: 1.5mm/rad < TTL/θ <1.8mm/rad,58 ° < θ <65 °, wherein TTL represents the distance on the optical axis from the object side surface to the imaging surface of the first group, and θ represents the maximum half field angle of the optical lens.
In some embodiments, the optical lens satisfies the following conditional expression: 2.8< TTL/f <3.5, wherein TTL represents the distance from the object side surface to the imaging surface of the first group on the optical axis, and f represents the effective focal length of the optical lens.
In some embodiments, the object-side surface of the first lens element is concave, and the image-side surface of the third lens element is convex.
In some embodiments, the optical lens satisfies the following conditional expression: 0.5< R1/R8<8, wherein R1 represents a radius of curvature of an object side surface of the first lens and R8 represents a radius of curvature of an image side surface of the third lens.
In some embodiments, the optical lens satisfies the following conditional expression: -6<f Q1/f < -0.8, where f Q1 represents the effective focal length of the first group and f represents the effective focal length of the optical lens.
In some embodiments, the optical lens satisfies the following conditional expression: 0.9< f Q2/f <1.1, where f Q2 represents an effective focal length of the second group and f represents an effective focal length of the optical lens.
In some embodiments, the optical lens satisfies the following conditional expression: -6<f Q1/fQ2 < -1 > wherein f Q1 represents the effective focal length of the first group and f Q2 represents the effective focal length of the second group.
On the other hand, the invention also provides an image pickup module, which comprises the optical lens and the imaging element, wherein the imaging element is used for converting an optical image formed by the optical lens into an electric signal.
Compared with the prior art, the optical lens provided by the invention adopts two groups of lens groups formed by bonding the substrate and the lens, and the diaphragm is arranged on the surface of the substrate, so that the machinability of the lens is improved, the focal power and the surface type collocation of each lens group are reasonably arranged, the size and the caliber of the lens are reduced to a certain extent while the large angle of view is met, the depth of field of the lens is effectively increased, and the requirements of the detection range and the observation depth of an endoscope can be well met.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will be apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings.
Fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present invention;
FIG. 2 is a graph showing a field curvature of an optical lens according to a first embodiment of the present invention;
FIG. 3 is a graph showing the MTF of an optical lens according to a first embodiment of the present invention;
FIG. 4 is a graph showing axial chromatic aberration of an optical lens according to a first embodiment of the present invention;
FIG. 5 is a schematic diagram of an optical lens according to a second embodiment of the present invention;
FIG. 6 is a graph showing a field curvature of an optical lens according to a second embodiment of the present invention;
FIG. 7 is a graph showing the MTF of an optical lens according to a second embodiment of the present invention;
FIG. 8 is a graph showing axial chromatic aberration of an optical lens according to a second embodiment of the present invention;
FIG. 9 is a schematic diagram of an optical lens according to a third embodiment of the present invention;
FIG. 10 is a graph showing a field curvature of an optical lens according to a third embodiment of the present invention;
FIG. 11 is a graph showing the MTF of an optical lens according to a third embodiment of the present invention;
FIG. 12 is a graph showing axial chromatic aberration of an optical lens according to a third embodiment of the present invention;
fig. 13 is a schematic structural diagram of an optical lens according to a fourth embodiment of the present invention.
Detailed Description
In order that the objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.
Furthermore, the terms "first," "second," "third," and the like, are used primarily to distinguish between different devices, elements or components (the particular species and configurations may be the same or different), and are not used to indicate or imply relative importance and amounts of the indicated devices, elements or components.
In this context, near the optical axis means the area near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.
The invention provides an optical lens which sequentially comprises a first group, a second group and protective glass from an object side to an imaging surface along an optical axis.
The first group has negative focal power and consists of a first lens and a first substrate which are connected in a gluing way in sequence from the object side to the imaging surface along the optical axis; the surface of the first lens, which is glued with the first substrate, is a plane; the first lens has negative focal power, and the object side surface of the first lens is a concave surface.
The second group has positive focal power and consists of a second lens, a second substrate and a third lens which are connected in sequence from the object side to the imaging surface along the optical axis; the second lens and the third lens are respectively glued on the object side surface and the image side surface of the second substrate; lenses are respectively arranged on the two surfaces of the second substrate, so that the aberration of the lens can be better corrected, and the imaging quality of the lens is improved. The surfaces of the second lens and the third lens glued with the second substrate are plane surfaces. The third lens has positive optical power; the image side surface of the third lens is a convex surface.
The first substrate and the second substrate can be glass substrates or plastic substrates with certain thickness and width, and the width (effective caliber) of the first substrate and the second substrate in the direction perpendicular to the optical axis is larger than the effective caliber of the glued lens, so that a stable forming environment can be provided for each lens, and meanwhile connection and assembly among different subsequent groups are facilitated.
More specifically, the thicknesses of the first substrate and the second substrate can be selected to be 0.05mm-0.3mm, the maximum effective caliber of the first substrate and the second substrate is smaller than 1.1mm, but the effective calibers of the first substrate and the second substrate are larger than the effective calibers of the lenses, so that the first substrate and the second substrate have better supporting and stabilizing effects for the lenses.
The lenses are connected with the substrate in a gluing mode, specifically, the first lens, the second lens and the third lens can be fixed on the first substrate and the second substrate in a nano imprinting or etching mode, so that the processing precision and the stability of the lenses can be ensured, and the miniaturization of the optical lens is realized.
The optical lens adopts a processing mode of stamping or etching a lens structure on the first glass or the second glass or the plastic substrate, and can realize wide angle and miniaturization of the lens and ensure that the lens has the characteristic of large depth of field. Preferably, the first lens, the second lens and the third lens all adopt a photoresist imprinting mode, the glued surface of the lens and the substrate is a plane, the surface of the lens far away from the substrate can be a spherical surface or an aspherical surface, and an aspherical lens is preferably adopted, so that the manufacturing cost can be effectively reduced, the weight is reduced, more excellent imaging effect can be provided, and the optical performance is more excellent.
The diaphragm is plated on the object side surface or the image side surface of the first substrate or the second substrate, and the diaphragm limits the aperture of the size of the incident light beam, so that the size and the position of the diaphragm have decisive effects on the definition, the imaging range and the brightness of the imaging of the lens. In order to better control the intensity of incident light, a diaphragm is arranged on the object side surface or the image side surface of the first substrate or the second substrate in a film plating mode, and compared with the diaphragm arranged on the aspheric surface or the spherical surface of the lens, the processing difficulty is reduced, and the processability of the lens is improved; the thin diaphragm film layer does not affect the gluing effect of the lens and the first substrate or the second substrate. In order to better play a role in converging the incident light, the effective aperture value of the diaphragm is set to be smaller, for example, may be 0.1mm or 0.12mm,0.15mm or other values, and the setting is specifically performed according to the actual situation, and the embodiment is not limited specifically.
Because the optical lens provided by the invention has smaller overall size, the processing difficulty of a single lens, the processing difficulty of a diaphragm and the processing precision of lens assembly are larger in a conventional mode, and the processing precision cannot be ensured, the first substrate and the second substrate are larger in width by arranging the lenses on the first substrate and the second substrate in a gluing way, so that a stable supporting effect can be provided for the positions of the lenses, and meanwhile, the first substrate and the second substrate are only required to be installed and fixed according to a preset space during lens assembly, the respective installation errors among a plurality of lenses are not required to be considered, the overall processing sensitivity is reduced, and the machinability of the lens is improved.
In some embodiments, the optical lens satisfies the following conditional expression: 0.09< F/f# <0.12, wherein F represents an effective focal length of the optical lens and f# represents an aperture value of the optical lens. The optical lens has a sufficiently large depth of field range, can realize clear imaging on an image plane when the object distance is 5mm to infinity, and is beneficial to enlarging the observation depth and detection range of the lens in the use process.
In some embodiments, the optical lens satisfies the following conditional expression: -8< f1/f3< -0.5,0.5< R1/R8<8, wherein f1 represents an effective focal length of the first lens, f3 represents an effective focal length of the third lens, R1 represents a radius of curvature of an object side of the first lens, and R8 represents a radius of curvature of an image side of the third lens. The lens has the advantages that the focal length and the surface shape of the first lens and the third lens are reasonably controlled, the incident angle and the emergent angle of light can be reasonably controlled, the correction difficulty of aberration is reduced while the large field angle of the lens is ensured to be realized, and the high-quality imaging of the lens is improved.
In some embodiments, the optical lens satisfies the following conditional expression: 0.5< f/H <0.65, wherein f represents the effective focal length of the optical lens, and H represents the image height corresponding to the maximum field angle of the optical lens. The lens has a larger imaging surface and can be matched with a larger imaging chip to realize high-definition imaging of the lens.
In some embodiments, the optical lens satisfies the following conditional expression: 1.5mm/rad < TTL/θ <1.8mm/rad,58 ° < θ <65 °, wherein TTL represents the distance on the optical axis from the object side surface to the imaging surface of the first group, and θ represents the maximum half field angle of the optical lens. The optical lens has smaller total optical length and larger angle of view, and can better realize the balance of small size and large visual angle.
In some embodiments, the optical lens satisfies the following conditional expression: 2.8< TTL/f <3.5, wherein TTL represents the distance from the object side surface to the imaging surface of the first group on the optical axis, and f represents the effective focal length of the optical lens. The optical lens can have smaller total optical length and better realize miniaturization of the lens by meeting the conditions.
In some embodiments, the optical lens satisfies the following conditional expression: -6<f Q1/f < -0.8, where f Q1 represents the effective focal length of the first group and f represents the effective focal length of the optical lens. The condition is satisfied, the incident light in a large field of view range is collected, the field angle of the lens is increased, and a large observation range is convenient to realize.
In some embodiments, the optical lens satisfies the following conditional expression: 0.9< f Q2/f <1.1, where f Q2 represents an effective focal length of the second group and f represents an effective focal length of the optical lens. The conditions are met, the second group has larger positive focal power, the aberration brought by the first group can be better corrected, meanwhile, the correction difficulty of the distortion of the marginal field of view is reduced, and the overall imaging quality is improved.
In some embodiments, the optical lens satisfies the following conditional expression: -6<f Q1/fQ2 < -1 > wherein f Q1 represents the effective focal length of the first group and f Q2 represents the effective focal length of the second group. The lens has the advantages that the focal power collocation of the first group and the second group is reasonably set, the incident angle of light can be properly increased, the angle of light incident on an image surface can be effectively controlled, the lens is ensured to have a larger angle of view, meanwhile, large image surface imaging is realized, and the balancing of wide angle and high-quality imaging of the lens is realized.
In some embodiments, the optical lens satisfies the following conditional expression: 0.2mm < CT Q1<0.7mm,0.1mm<CTQ2 <0.8mm, where CT Q1 represents the central thickness of the first group on the optical axis and CT Q2 represents the central thickness of the second group on the optical axis. The thickness of each group is reasonably set, so that miniaturization of the lens is realized, meanwhile, lens forming and assembly are facilitated, and the product yield is ensured.
In some embodiments, the optical lens satisfies the following conditional expression: 0.9< D/H <1.1, wherein D represents the maximum effective caliber of the first substrate and the second substrate, and H represents the image height corresponding to the maximum field angle of the optical lens. The lenses are respectively glued on the first substrate and the second substrate, and the effective caliber of each lens is smaller than that of each substrate, so that the conditions are met, the lens is ensured to have smaller external caliber and smaller volume, the field angle of the lens is increased, the imaging range of the lens is enlarged, and the larger observation range is realized. In some embodiments, the apertures of the first substrate and the second substrate are equal, which is beneficial to processing and assembling the components of each group (including the substrate and the lens) into the lens, and improves the assembly yield.
In some embodiments, the total optical length of the optical lens is 1.5mm < ttl <2.0mm, the maximum field angle of the optical lens is 116 ° < FOV <130 °, and the image height corresponding to the maximum field angle of the optical lens is 0.9mm < h <1 mm.
The optical lens provided by the invention adopts two groups of lens groups glued by the substrate and the lens, and by reasonably setting the focal power and the surface type collocation of each lens group, the lens has a large field angle (FOV can reach 120 degrees) and smaller total length, and simultaneously the depth of field of the lens is effectively increased, so that the lens can realize high-definition imaging in 5mm to infinite working object distance, and the requirements of the endoscope detection range, observation depth and definition can be well met.
In the embodiments of the present invention, when the lens surface type in the optical lens is an aspherical surface, the aspherical surface type of each lens satisfies the following equation:
；
Where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h in the optical axis direction, c is the paraxial curvature of the surface, k is a quadric surface coefficient, and a 2i is an aspherical surface type coefficient of 2 i-th order.
The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.
First embodiment
Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present invention is shown, where the optical lens 100 includes, in order from an object side to an imaging plane along an optical axis: a first group Q1 having negative power, a second group Q2 having positive power, and a cover glass G3.
The first group Q1 includes, in order from the object side to the imaging plane along the optical axis, a first lens L1 and a first substrate G1. The thickness of the first substrate G1 in the optical axis direction is 0.265mm, and the object side surface S2 and the image side surface S3 of the first substrate G1 are both planes. The first lens L1 has negative optical power, the object-side surface S1 of the first lens L1 is concave, the image-side surface is planar, and the image-side surface of the first lens L1 is bonded on the object-side surface S2 of the first substrate G1 by nano imprinting.
The second group Q2 includes, in order from the object side to the imaging surface along the optical axis, a second lens L2, a second substrate G2, and a third lens L3. The thickness of the second substrate G2 in the optical axis direction is 0.172mm, and the object side surface S6 and the image side surface S7 of the second substrate G2 are both planar. The second lens L2 has positive optical power, the object-side surface S5 of the second lens L2 is convex, the image-side surface is planar, and the image-side surface of the second lens L2 is bonded on the object-side surface S6 of the second substrate G2 by nano imprinting. The third lens element L3 has positive refractive power, wherein an object-side surface of the third lens element L3 is a planar surface, and an image-side surface S8 is a convex surface, and the object-side surface of the third lens element L3 is bonded to the image-side surface S7 of the second substrate G2 by nanoimprinting. The diaphragm ST is plated on the image side surface S7 of the second substrate G2 in a film plating mode, and the effective caliber of the diaphragm ST is 0.12mm.
The thickness of the cover glass G3 in the optical axis direction is 0.300mm, and the object side surface S9 and the image side surface S10 of the cover glass G3 are both flat surfaces for protecting the imaging chip.
The first substrate G1, the second substrate G2 and the protective glass G3 are made of glass materials, so that imprinting of the lens and assembly of the lens can be better realized.
The object side surface S1 of the first lens element L1, the object side surface S5 of the second lens element L2, and the image side surface S8 of the third lens element L3 are aspheric. The first lens L1, the second lens L2 and the third lens L3 are made of plastic materials which are convenient to produce, so that the nanoimprint lens is convenient to form on one hand, and the volume and the weight of the lens can be reduced on the other hand.
The relevant parameters of each lens in the optical lens 100 provided in this embodiment are shown in table 1.
TABLE 1
The surface profile coefficients of the aspherical surfaces of the optical lens 100 in this embodiment are shown in table 2.
TABLE 2
In the present embodiment, graphs of curvature of field, MTF, and axial chromatic aberration of the optical lens 100 are shown in fig. 2, 3, and 4, respectively.
In fig. 2, the field Qu Quxian represents the field curvature of the meridian direction and the sagittal direction at different image heights of the image plane, the horizontal axis represents the offset (unit: mm) in the figure, and the vertical axis represents the angle of view (unit: degree), and as seen from the figure, the field curvature offset of the meridian direction and the sagittal direction at the image plane is controlled within ±0.09 mm, which indicates that the field curvature of the optical lens 100 is well corrected.
In fig. 3, the MTF curve represents the degree of modulation of lens imaging at a frequency of 75lp/mm at different fields of view, the horizontal axis represents the angle of view (in degrees), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF values of the optical lens 100 in the present embodiment are all above 0.5 in the full field of view, and the MTF curves are approximately horizontal in the process from the center to the edge field of view, which indicates that the optical lens 100 has better imaging quality and better detail resolution under the full field of view.
The axial chromatic aberration curves of fig. 4 represent aberrations at different wavelengths on the optical axis at the imaging plane, with the horizontal axis representing the offset (in millimeters) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset amount of the axial chromatic aberration is controlled within ±0.05 mm, which indicates that the optical lens 100 can effectively correct the aberration of the fringe field of view.
Second embodiment
Referring to fig. 5, a schematic diagram of an optical lens 200 according to a second embodiment of the present invention is shown, and the optical lens 200 in the present embodiment is substantially the same as the optical lens 100 in the first embodiment, except that a diaphragm ST is plated on an object side surface S6 of a second substrate G2, and the curvature radius, aspheric coefficients, lens thickness, thickness of the substrate, etc. of each lens surface are different.
Specifically, the relevant parameters of each lens in the optical lens 200 provided in this embodiment are shown in table 3.
TABLE 3 Table 3
The surface profile coefficients of the aspherical surfaces of the optical lens 200 in this embodiment are shown in table 4.
TABLE 4 Table 4
In the present embodiment, graphs of curvature of field, MTF, and axial chromatic aberration of the optical lens 200 are shown in fig. 6, 7, and 8, respectively.
As can be seen from fig. 6, the curvature of field offset in the meridian direction and the sagittal direction at the image plane are controlled within ±0.05 mm, which indicates that the curvature of field of the optical lens 200 is well corrected.
As can be seen from fig. 7, the MTF values of the optical lens 200 in the present embodiment are all above 0.55 in the full field of view, and the MTF curves are approximately horizontal in the process from the center to the edge field of view at the frequency of 75lp/mm, which indicates that the optical lens 200 has better imaging quality and better detail resolution in the full field of view.
As can be seen from fig. 8, the offset amount of the axial chromatic aberration is controlled within ±0.06 millimeters, indicating that the optical lens 200 can effectively correct the aberration of the fringe field of view.
Third embodiment
Referring to fig. 9, a schematic diagram of an optical lens 300 according to a third embodiment of the present invention is shown, and the optical lens 300 in the present embodiment is substantially the same as the optical lens 100 in the first embodiment, except that a diaphragm ST is plated on an object side surface S6 of a second substrate G2, the object side surface S5 of the second lens is concave, the second lens L2 has negative focal power, and the radius of curvature, the aspheric coefficient, the thickness of the substrate, etc. of each lens face are different. Specifically, the relevant parameters of each lens in the optical lens 300 provided in this embodiment are shown in table 5.
TABLE 5
The surface profile coefficients of the aspherical surfaces of the optical lens 300 in this embodiment are shown in table 6.
TABLE 6
In the present embodiment, graphs of curvature of field, MTF, and axial chromatic aberration of the optical lens 300 are shown in fig. 10, 11, and 12, respectively.
As can be seen from fig. 10, the curvature of field offset in the meridian direction and the sagittal direction at the image plane are both controlled within ±0.05 mm, indicating that the curvature of field of the optical lens 300 is well corrected.
As can be seen from fig. 11, the MTF values of the optical lens 300 in the present embodiment are all above 0.55 in the full field of view, and the MTF curves are approximately horizontal in the process from the center to the edge field of view at the frequency of 75lp/mm, which indicates that the optical lens 300 has better imaging quality and better detail resolution in the full field of view.
As can be seen from fig. 12, the offset amount of the axial chromatic aberration is controlled within ±0.06 millimeters, indicating that the optical lens 300 can effectively correct the aberration of the fringe field of view.
Referring to table 7, the correlation values of the optical lens provided in the above three embodiments and each of the above conditional expressions are shown.
TABLE 7
Fourth embodiment
Referring to fig. 13, a fourth embodiment of the present invention provides an image capturing module 400, where the image capturing module 400 may include an imaging element 410 and an optical lens (e.g., the optical lens 100) according to any of the above embodiments. The imaging element 410 may be a CMOS (Complementary Metal Oxide Semiconductor ) image sensor or a CCD (Charge Coupled Device, charge coupled device) image sensor.
The image pickup module 400 may be any of a medical endoscope, an industrial endoscope, a capsule lens, and a camera equipped with the optical lens according to any of the above embodiments.
The image capturing module 400 provided in this embodiment includes the optical lens in any of the above embodiments, and because of the characteristics of small size, small caliber and large field of view of the optical lens, the image capturing module 400 with the optical lens also has the advantages of small size, small caliber and large field of view, and can well meet the requirements of the endoscope on the detection range and the observation depth.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (10)
1. An optical lens is characterized by comprising a first group, a second group and protective glass in sequence from an object side to an imaging surface along an optical axis;
the first group has negative focal power, and consists of a first lens and a first substrate which are connected in a gluing way in sequence from the object side to the imaging surface along the optical axis, wherein the first lens has negative focal power;
the second group has positive focal power and consists of a second lens, a second substrate and a third lens which are connected in sequence from the object side to the imaging surface along the optical axis; the third lens has positive optical power;
a diaphragm is plated on the object side surface or the image side surface of the first substrate or the second substrate;
Wherein, the optical lens satisfies the conditional expression: 0.09< F/f# <0.12, -8< F1/F3< -0.5,0.5< F/H <0.65, F represents an effective focal length of the optical lens, f# represents an aperture value of the optical lens, F1 represents an effective focal length of the first lens, F3 represents an effective focal length of the third lens, and H represents an image height corresponding to a maximum field angle of the optical lens.
2. The optical lens of claim 1, wherein the glue joint comprises a nanoimprint or an etching.
3. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 1.5mm/rad < TTL/θ <1.8mm/rad,58 ° < θ <65 °, wherein TTL represents the distance on the optical axis from the object side surface to the imaging surface of the first group, and θ represents the maximum half field angle of the optical lens.
4. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 2.8< TTL/f <3.5, wherein TTL represents the distance from the object side surface to the imaging surface of the first group on the optical axis, and f represents the effective focal length of the optical lens.
5. The optical lens of claim 1, wherein the object-side surface of the first lens element is concave and the image-side surface of the third lens element is convex.
6. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< R1/R8<8, wherein R1 represents a radius of curvature of an object side surface of the first lens and R8 represents a radius of curvature of an image side surface of the third lens.
7. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -6<f Q1/f < -0.8, where f Q1 represents the effective focal length of the first group and f represents the effective focal length of the optical lens.
8. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.9< f Q2/f <1.1, where f Q2 represents an effective focal length of the second group and f represents an effective focal length of the optical lens.
9. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -6<f Q1/fQ2 < -1 > wherein f Q1 represents the effective focal length of the first group and f Q2 represents the effective focal length of the second group.
10. An imaging module comprising the optical lens of any one of claims 1-9 and an imaging element for converting an optical image formed by the optical lens into an electrical signal.
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| CN116009221A (en) * | 2023-03-24 | 2023-04-25 | 联创电子科技股份有限公司 | Optical lens and camera module |
| JP2023112225A (en) * | 2022-02-01 | 2023-08-14 | キヤノン株式会社 | Optical system and imaging device |
| CN219978614U (en) * | 2022-09-27 | 2023-11-07 | 江西欧菲光学有限公司 | Optical lens, camera module and electronic equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US7027231B2 (en) * | 2003-02-14 | 2006-04-11 | Fujinon Corporation | Endoscope objective lens |
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| JPH0784179A (en) * | 1993-07-19 | 1995-03-31 | Asahi Optical Co Ltd | Objective lens for endoscope |
| CN102650724A (en) * | 2011-02-23 | 2012-08-29 | 大立光电股份有限公司 | Wide-angle photographing lens assembly |
| CN113126253A (en) * | 2021-03-04 | 2021-07-16 | 重庆融豪太视科技有限公司 | High-resolution direct-injection type short-focus projection lens |
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| JP2023112225A (en) * | 2022-02-01 | 2023-08-14 | キヤノン株式会社 | Optical system and imaging device |
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