CN111025606A - Super wide-angle pinhole lens and camera equipment - Google Patents
Super wide-angle pinhole lens and camera equipment Download PDFInfo
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- CN111025606A CN111025606A CN201911389048.5A CN201911389048A CN111025606A CN 111025606 A CN111025606 A CN 111025606A CN 201911389048 A CN201911389048 A CN 201911389048A CN 111025606 A CN111025606 A CN 111025606A
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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
- G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
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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
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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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Abstract
The embodiment of the invention discloses a super-wide-angle pinhole lens and camera equipment, wherein the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the direction from an object side to an image side, the first lens is a meniscus lens with negative focal power and a convex surface facing to the object side, and the second lens is a double-convex lens with positive focal power; the third lens is a convex-concave lens with positive focal power and a convex surface facing to the object side; the fourth lens is a biconvex lens with positive focal power; the fifth lens is a meniscus lens with negative focal power and a concave surface facing the object side. The invention effectively reduces the volume of the short-focus lens and increases the field angle of the lens by reasonably using the double cemented lens and limiting the focal power of each lens. The invention has the characteristics of high resolution, short focal length, large field angle and strong environmental temperature change resistance, and overcomes the defects in the prior art.
Description
Technical Field
The invention relates to the technical field of optical lens modules, in particular to an ultra-wide-angle pinhole lens and camera equipment.
Background
The pinhole imaging system is based on the principle of pinhole imaging, light enters from a pinhole, is focused by an optical lens of the imaging system and then is imaged on a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor) image detector at the rear end, and because the light inlet hole at the front end is small and is not easy to be perceived, the pinhole imaging system is widely applied to the fields of traffic monitoring, public place monitoring, safety monitoring and the like, and the life and property safety of people is guaranteed. The traditional pinhole lens has a small opening at the opening end, only a few millimeters, so that a large imaging field of view is difficult to obtain, and the using effect is influenced. The ultra-wide-angle pinhole lens brings larger imaging visual field and corrects aberration while considering the diameter of the small opening.
For example, the invention patent with the application number of 201810119445.X and the name of the invention of an ultra-large field pinhole optical imaging system has the defects of small field angle, small monitoring range, complex structure, high cost and high assembly difficulty.
Disclosure of Invention
The technical problem to be solved by the embodiments of the present invention is to provide an ultra-wide-angle pinhole lens and a camera device, so as to take account of small aperture diameter, ultra-wide angle and high resolution, so that the pinhole technology can be applied to a larger imaging field of view, and fill up the blank in the pinhole lens market.
In order to solve the foregoing technical problem, an embodiment of the present invention provides a super-wide-angle pinhole lens, including a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element sequentially arranged along a direction from an object side to an image side, where the first lens element is a meniscus lens element with a negative focal power and a convex surface facing the object side, and the second lens element is a double-convex lens element with a positive focal power; the third lens is a convex-concave lens with positive focal power and a convex surface facing to the object side; the fourth lens is a biconvex lens with positive focal power; the fifth lens is a meniscus lens with negative focal power and a concave surface facing the object side;
the focal length of the first lens is f1The focal length of the second lens is f2The integral focal length of the ultra-wide-angle pinhole lens is f, and the relationship is satisfied: -1.26<f1/f<-0.48，1.49<f2/f<1.95。
Further, the refractive index nd3 of the third lens satisfies the following relation: nd3 is more than or equal to 1.44 and less than or equal to 1.75.
Further, the lens further comprises an optical diaphragm device, and the optical diaphragm device is positioned between the first lens and the second lens.
Further, the refractive index of the fifth lens is nd5, and satisfies the relation: nd5> 1.9.
Further, the fourth lens and the fifth lens are cemented with each other to form a cemented lens set.
Further, the third lens is a plastic aspheric lens.
Correspondingly, the embodiment of the invention also provides the camera equipment, which comprises the ultra-wide-angle pinhole lens.
The invention has the beneficial effects that: the focal length is short, the field angle is large (reaching more than 162 degrees), the details of the object are clearer, and the recognition effect is better; the five lenses are combined, so that the cost is low, the investment of the glass-plastic mixing technology is lower, and the period is shorter; the environmental temperature change resistance is strong.
Drawings
Fig. 1 is a schematic structural diagram of an ultra-wide-angle pinhole lens according to an embodiment of the present invention.
Fig. 2 is an MTF analysis diagram of an ultra-wide-angle pinhole lens according to an embodiment of the present invention at 20 degrees.
Fig. 3 is a CRA exit angle curve diagram of the ultra-wide-angle pinhole lens according to the embodiment of the invention.
Fig. 4 is a field curvature diagram of an ultra-wide-angle pinhole lens according to an embodiment of the invention.
Fig. 5 is an MTF analysis diagram of the ultra-wide-angle pinhole lens according to the embodiment of the present invention at a temperature of-20 degrees below zero.
FIG. 6 is an analytic graph of MYF of an ultra-wide-angle pinhole lens at-60 degrees at high temperature according to an embodiment of the invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict, and the present invention is further described in detail with reference to the drawings and specific embodiments.
If directional indications (such as up, down, left, right, front, and rear … …) are provided in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the movement, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are only used for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.
Referring to fig. 1 to 6, the super-wide-angle pinhole lens according to the embodiment of the present invention includes a first lens element 1, a second lens element 2, a third lens element 3, a fourth lens element 4, and a fifth lens element 5 sequentially disposed along an object side to an image side.
The first lens 1 is a meniscus lens with negative focal power and a convex surface facing the object side, and the second lens 2 is a double-convex lens with positive focal power; the third lens 3 is a convex-concave lens with positive focal power and a convex surface facing the object side; the fourth lens 4 is a biconvex lens with positive focal power; the fifth lens 5 is a meniscus lens with negative focal power and a concave surface facing the object side. In fig. 1, S1 and S2 are both surfaces of the first lens 1, S3 and S4 are both surfaces of the second lens 2, S5 and S6 are both surfaces of the third lens 3, S7 and S8 are both surfaces of the fourth lens 4, and S8 and S9 are both surfaces of the fifth lens 5 (S8 is a common surface of the fifth lens 5 and the fourth lens 4).
The first lens 1 has a focal length f1The focal length of the second lens 2 is f2. The integral focal length of the ultra-wide-angle pinhole lens is f, and the relationship is satisfied as follows: -1.26<f1/f<-0.48，1.49<f2/f<1.95。
As an embodiment, the refractive index nd3 of the third lens 3 satisfies the following relation: nd3 is more than or equal to 1.44 and less than or equal to 1.75.
In one embodiment, the ultra-wide-angle pinhole lens further includes an aperture stop device ST located between the first lens 1 and the second lens 2.
As an embodiment, the refractive index of the fifth lens 5 is nd5, and satisfies the relation: nd5> 1.9.
As an embodiment, the fourth lens 4 and the fifth lens 5 are cemented with each other to form a cemented lens set.
In one embodiment, the third lens element 3 is a plastic aspheric lens.
According to the embodiment of the invention, the double cemented lens is reasonably used, the focal power of each lens is limited, the volume of the short-focus lens is effectively reduced, and the field angle of the lens is increased. The invention has the characteristics of high resolution, short focal length, large field angle and strong environmental temperature change resistance, and overcomes the defects in the prior art.
Example (b): the optical system FOV of the ultra-wide-angle pinhole lens is 162 degrees, the total focal length of the lens is 2.34mm, and each lens of the fixed-focus lens meets the conditions listed in Table 1, wherein Surf is a surface number, Radius is a curvature Radius, Thickness is the Thickness of the lens, Index is a refractive Index, ABB is an ABB coefficient, and EFL-E is a focal length; the parameters of the lens group are listed in sequence in table 1:
TABLE 1
| surf | Radius | Thickness | Index | ABB | EFL-E | |
| | INFINITY | INFINITY | ||||
| 1 | 3.795199167 | 0.6 | 1.77 | 49.6 | -2.21 | |
| 2 | 1.09637444 | 0.946535 | ||||
| STO | INFINITY | 0.209046 | ||||
| 4 | 24.43252677 | 2.447946 | 1.55 | 75.5 | 3.92 | |
| 5 | -2.284877529 | 0.1 | ||||
| 6 | 15.57426326 | 1.062762 | 1.54 | 55.8 | 13.71 | |
| 7 | -13.54182186 | 0.1 | ||||
| 8 | 6.307968417 | 2.257185 | 1.75 | 52.3 | 3.39 | |
| 9 | -3.651321122 | 0.6 | 1.95 | 17.9 | -4.14 | |
| 10 | -57.20519002 | 2.896457 | ||||
| IMA | INFINITY | - |
The third lens element 3 is a plastic aspheric lens element, and aspheric data are shown in table 2:
TABLE 2
| SURFACE:6 | SURFACE:7 | |
| K | -133.774916 | -8.216487388 |
| E4 | 0.018146051 | 0.014876851 |
| E6 | -0.000732866 | 0.001092324 |
| E8 | 1.10725E-05 | 1.77051E-05 |
| E10 | -5.84423E-06 | -2.1788E-05 |
From table 1, it can be seen:
f1/f＝-2.21/2.34＝-0.944；
f2/f＝3.92/2.34＝1.675；
Nd3＝1.54；
Nd5＝1.95；
all meet the requirements. In the embodiment of the invention, the volume of the short-focus lens is effectively reduced and the field angle of the lens is increased by reasonably using the double cemented lens and limiting the focal power of each lens. The high-resolution high-focus lens has the characteristics of high resolution, short focal length, large field angle and strong environment temperature change resistance, and overcomes the defects in the prior art.
As shown in fig. 2, a Modulation Transfer Function (MTF) value diagram at 20 degrees celsius of the embodiment is shown, the MTF value diagram is based on the parameters in table 1, and the most important measurement of the quality of the optical lens, such as the resolution, etc., the MTF value is defined to be certainly greater than 0 and less than 1, and the higher the MTF value is, the more excellent the performance of the optical lens is, i.e., the resolution is high; the variable is the spatial frequency, namely how many lines can be presented in a range of one mm to measure the spatial frequency, and the unit is expressed by lp/mm; the fixed high frequency (e.g., 160lp/mm) curve represents the lens resolution characteristic, the higher this curve, the higher the lens resolution, and the ordinate is the MTF value. The abscissa is the spatial frequency. In addition, at a position deviated from the center of the image field, MTF values measured by the sinusoidal grating of the line in the tangential direction and the line in the radial direction are different. The MTF curve produced by a line parallel to the diameter is called the sagittal curve, denoted s (sagittal), and the MTF curve produced by a line parallel to the tangent is called the meridional curve, denoted t (meridian). Therefore, there are generally two MTF curves, i.e. S curve and T curve, and there are multiple sets of MTF variation curves in fig. 2 with spatial frequency as abscissa, which reflects that the lens system has higher resolution and the optical performance is greatly improved compared with the current mainstream optical system.
Fig. 3 is a diagram of chief ray angles corresponding to the optical lens, that is, the abscissa of the exit angle diagram of the lens is the field angle of the lens, the leftmost side is the center of the lens, and the rightmost side is the maximum field angle of the lens. The maximum field angle is about 15.6 degrees to CRA, is less than 20 degrees, and is well matched with the chip, so that the imaging quality is improved.
The curvature of field corresponding to the visible part of the lens system is smaller as the curve is closer to the y-axis. As shown in FIG. 4, the field curvature is controlled within the range of-0.1% to 0.1%. Fig. 5 is an analysis view at 20 degrees below zero, and fig. 6 is an analysis view at 60 degrees above zero.
The camera equipment comprises the ultra-wide-angle pinhole lens.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A super wide-angle pinhole lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the direction from an object side to an image side, and is characterized in that the first lens is a meniscus lens with negative focal power and a convex surface facing to the object side, and the second lens is a double-convex lens with positive focal power; the third lens is a convex-concave lens with positive focal power and a convex surface facing to the object side; the fourth lens is a biconvex lens with positive focal power; the fifth lens is a meniscus lens with negative focal power and a concave surface facing the object side;
the focal length of the first lens is f1The focal length of the second lens is f2The integral focal length of the ultra-wide-angle pinhole lens is f, and the relationship is satisfied: -1.26<f1/f<-0.48，1.49<f2/f<1.95。
2. The ultra-wide angle pinhole lens of claim 1 wherein the refractive index nd3 of the third lens satisfies the following relationship: nd3 is more than or equal to 1.44 and less than or equal to 1.75.
3. The ultra-wide angle pinhole lens of claim 1 further comprising an aperture device, said aperture device being positioned between the first lens and the second lens.
4. The ultra-wide angle pinhole lens of claim 1 wherein the fifth lens has a refractive index nd5 and satisfies the relationship: nd5> 1.9.
5. The ultra-wide angle pinhole lens of claim 1 wherein the fourth lens and the fifth lens are cemented to each other to form a cemented set of lenses.
6. The ultra-wide angle pinhole lens of claim 1 wherein the third lens element is a plastic aspheric lens.
7. An image pickup apparatus comprising the ultra-wide-angle pinhole lens according to any one of claims 1 to 6.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911389048.5A CN111025606A (en) | 2019-12-30 | 2019-12-30 | Super wide-angle pinhole lens and camera equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911389048.5A CN111025606A (en) | 2019-12-30 | 2019-12-30 | Super wide-angle pinhole lens and camera equipment |
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| CN111025606A true CN111025606A (en) | 2020-04-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111538138A (en) * | 2020-07-09 | 2020-08-14 | 瑞声通讯科技(常州)有限公司 | Image pickup optical lens |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11249016A (en) * | 1998-02-27 | 1999-09-17 | Fuji Photo Optical Co Ltd | Wide-angle zoom lens |
| KR100781901B1 (en) * | 2006-05-30 | 2007-12-04 | 정수용 | Optical system for broadband security camera |
| CN201464692U (en) * | 2009-03-31 | 2010-05-12 | 河南同城光电有限公司 | pinhole lens |
| CN208026985U (en) * | 2018-03-20 | 2018-10-30 | 嘉兴中润光学科技有限公司 | Miniature high-definition medical treatment camera lens |
-
2019
- 2019-12-30 CN CN201911389048.5A patent/CN111025606A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11249016A (en) * | 1998-02-27 | 1999-09-17 | Fuji Photo Optical Co Ltd | Wide-angle zoom lens |
| KR100781901B1 (en) * | 2006-05-30 | 2007-12-04 | 정수용 | Optical system for broadband security camera |
| CN201464692U (en) * | 2009-03-31 | 2010-05-12 | 河南同城光电有限公司 | pinhole lens |
| CN208026985U (en) * | 2018-03-20 | 2018-10-30 | 嘉兴中润光学科技有限公司 | Miniature high-definition medical treatment camera lens |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111538138A (en) * | 2020-07-09 | 2020-08-14 | 瑞声通讯科技(常州)有限公司 | Image pickup optical lens |
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Application publication date: 20200417 |