High-definition and low-distortion projection lens

Abstract

The utility model discloses a high-definition and low-distortion projection lens, which relates to the technical field of optical lenses and comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object plane to an image plane along an optical axis. The first lens, the second lens, the third lens, the fourth lens and the fifth lens are all arranged in the lens barrel, and a diaphragm is arranged between the third lens and the fourth lens. A first lens, a second lens, a third lens, a fourth lens and a fifth lens are sequentially arranged from an object plane to an image plane along an optical axis; the first lens is a positive focal power lens, the second lens is a positive focal power lens, the third lens is a negative focal power lens, the fourth lens is a positive focal power lens, and the fifth lens is a negative focal power lens. By reasonably setting the focal power of each lens, the lens is ensured to have higher image resolution under the conditions of small size and low cost, and the high-definition imaging requirement is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical lens technical field, concretely relates to a high definition and low distortion projection lens. BACKGROUND

[0002] With the rise of machine vision detection industry, users have put forward higher requirements on the resolution, image quality and purchase cost of industrial lenses.

[0003] At present, the lens has the following constraints: resolution limit, the lens may have a resolution limit, resulting in insufficient clarity or accuracy of the detected details; optical distortion, the lens may have optical distortion, such as chromatic aberration, distortion, etc., which may not be accurate or may have color distortion. The number of lenses inside the lens is also an important factor affecting the overall cost, how to reduce the cost while achieving high quality is also a problem that must be considered, therefore, how to design a picture zoom lens with high imaging quality, small structure, low picture distortion rate and image brightness meeting the requirements under the condition of limited cost is one of the technical problems in the design of detection lens at present, therefore, a high definition and low distortion projection lens is proposed. UTILITY MODEL CONTENT

[0004] The utility model provides a high definition and low distortion projection lens to solve the problems in the above background technology.

[0005] To solve the above technical problems, the technical scheme adopted by the utility model is:

[0006] A high definition and low distortion projection lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order along the optical axis from the object plane to the image plane, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all arranged inside the lens barrel, and a diaphragm is arranged between the third lens and the fourth lens.

[0007] The further improvement of the technical scheme of the utility model is that the first lens is a positive focal length lens, the second lens is a positive focal length lens, the third lens is a negative focal length lens, the fourth lens is a positive focal length lens, and the fifth lens is a negative focal length lens, and the fifth lens is arranged as an image plane away from the fourth lens, and the first lens is arranged as an object plane away from the second lens.

[0008] The further improvement of the technical scheme of the utility model is that the second lens and the third lens form a cemented lens group, and the first lens, the second lens, the third lens and the fourth lens are all glass spherical lenses.

[0009] The further improvement in the technical scheme of the utility model lies in that the curvature radius of the object plane side surface of the first lens is R11, 30.5mm < R11 < 32.5mm, and the curvature radius of the image plane side surface of the first lens is R12, -78.2mm < R12 < -80.2mm.

[0010] The further improvement in the technical scheme of the utility model lies in that the curvature radius of the object plane side surface of the second lens is R21, 11.3mm < R21 < 13.3mm, and the curvature radius of the image plane side surface of the second lens is R22, -19.8mm < R22 < -21.8mm.

[0011] The further improvement in the technical scheme of the utility model lies in that the curvature radius of the object plane side surface of the third lens is R31, -19.8mm < R31 < -21.8mm, and the curvature radius of the image plane side surface of the third lens is R32, 14.2mm < R32 < 16.2mm.

[0012] The further improvement in the technical scheme of the utility model lies in that the curvature radius of the object plane side surface of the fourth lens is R41, 16.2mm < R41 < 18.2mm, and the curvature radius of the image plane side surface of the fourth lens is R42, -1695mm < R42 < -1697mm.

[0013] The further improvement in the technical scheme of the utility model lies in that the curvature radius of the object plane side surface of the fifth lens is R51, -12.3mm < R51 < -14.3mm, and the curvature radius of the image plane side surface of the fifth lens is R52, 2063mm < R52 < 2065mm.

[0014] The further improvement in the technical scheme of the utility model lies in that the side, away from the fourth lens, of the fifth lens is provided with a pressing ring for fixing the lens into the lens barrel, and the side, away from the fifth lens (105), of the pressing ring is provided with a flange plate for fixing the lens to the surface of the optical machine.

[0015] The further improvement in the technical scheme of the utility model lies in that the distance from the optical axis center of the object plane side surface of the first lens to the image plane is TTL, wherein, 95mm < TTL < 98mm.

[0016] Thanks to the adoption of the above technical scheme, the utility model has the following technical progress compared with the prior art:

[0017] The utility model provides a kind of high definition and low distortion projection lens, first lens, second lens, third lens, fourth lens and fifth lens are sequentially arranged along optical axis from object plane to image plane;First lens is positive power lens, second lens is positive power lens, third lens is negative power lens, fourth lens is positive power lens and fifth lens is negative power lens.By the refractive power of each lens is reasonably set, ensure that lens has higher image resolving power in the case of small size, low cost, meet the requirement of high definition imaging. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the sectional structure schematic diagram of the utility model;

[0019] Figure 2 It is the visible light point column diagram of the utility model;

[0020] Figure 3 It is the field curvature distortion diagram of the utility model;

[0021] Figure 4 It is the MTF diagram of the utility model.

[0022] In the drawing: 101, first lens;102, second lens;103, third lens;104, fourth lens;105, fifth lens;106, lens barrel;107, compression ring;108, flange plate;109, diaphragm. DETAILED DESCRIPTION

[0023] The utility model is further explained in detail in connection with embodiment as follows:

[0024] Embodiment 1

[0025] As Figures 1-4 Indicated, the utility model provides a kind of high definition and low distortion projection lens, including first lens 101, second lens 102, third lens 103, fourth lens 104 and fifth lens 105 sequentially arranged along optical axis from object plane to image plane, first lens 101, second lens 102, third lens 103, fourth lens 104 and fifth lens 105 are all arranged in the inside of lens barrel 106, and the light barrier 109 is arranged between third lens 103 and fourth lens 104, first lens 101 is positive power lens, second lens 102 is positive power lens, third lens 103 is negative power lens, fourth lens 104 is positive power lens, and fifth lens 105 is negative power lens, the side of fifth lens 105 away from fourth lens 104 is set as image plane, and the side of first lens 101 away from second lens 102 is set as object plane.

[0026] In the embodiment, the optical power is equal to the difference between the converging degree of the light beam on the image plane side and the converging degree of the light beam on the object plane side, which represents the ability of the optical system to deflect light. The greater the absolute value of the optical power, the stronger the bending ability of the light, the smaller the absolute value of the optical power, the weaker the bending ability of the light, when the optical power is positive, the refraction of the light is convergent; when the optical power is negative, the refraction of the light is divergent. The optical power can be used to represent a certain refractive surface of a lens, that is, a surface of the lens, and can be used to represent a certain lens, or can be used to represent a system formed by multiple lenses, that is, a lens group. Each lens can be fixed in a lens barrel 106. The first lens 101 is a positive optical power lens, which is used to control the incidence angle of the light of the optical system. The second lens 102 is a positive optical power lens, the third lens 103 is a negative optical power lens, the fourth lens 104 is a positive optical power lens, and the fifth lens is a negative optical power lens. Reasonable setting of the optical power of each lens can correct off-axis aberrations, including field curvature, coma, astigmatism and other aberrations. The optical power of the entire optical lens is distributed in a certain proportion to ensure the balance of the incidence angle of the front and rear groups of lenses, so as to reduce the sensitivity of the lens, improve the production possibility, and reasonably set the number of lenses and the optical power of each lens. Under the premise of low cost, the balance of the incidence angle of the front and rear groups of lenses is ensured, the sensitivity of the lens is reduced, the production possibility is improved, the production cost is reduced, the lens has high resolution, the imaging quality is improved, and the high-definition image quality demand is met.

[0027] Embodiment 2

[0028] As Figures 1-4As shown, on the basis of embodiment 1, the utility model provides a technical scheme: preferably, second lens 102 and third lens 103 constitute cemented lens group, first lens 101, second lens 102, third lens 103 and fourth lens 104 are all glass spherical lens, the curvature radius of the object side surface of first lens 101 is R11, 30.5mm < R11 < 32.5mm, the curvature radius of the image side surface of first lens 101 is R12, -78.2mm < R12 < -80.2mm, the curvature radius of the object side surface of second lens 102 is R21, 11.3mm < R21 < 13.3mm, the curvature radius of the image side surface of second lens 102 is R22, -19.8mm < R22 < -21.8mm, the curvature radius of the object side surface of third lens 103 is R31, -19.8mm < R31 < -21.8mm, the curvature radius of the image side surface of third lens 103 is R32, 14.2mm < R32 < 16.2mm, the curvature radius of the object side surface of fourth lens 104 is R41, 16.2mm < R41 < 18.2mm, the curvature radius of the image side surface of fourth lens 104 is R42, -1695mm < R42 < -1697mm, the curvature radius of the object side surface of fifth lens 105 is R51, -12.3mm < R51 < -14.3mm, the curvature radius of the image side surface of fifth lens 105 is R52, 2063mm < R52 < 2065mm.

[0029] In the embodiment, by reasonably setting the surface type of each lens, the power of each lens is ensured to meet the power requirement, and the entire lens structure is also ensured to be compact and high in integration, the image side surface of the second lens 102 and the object side surface of the third lens 103 are cemented and fixed to form a cemented lens group with positive power, which has good aberration correction function and helps to improve the system optical performance and tolerance, while reducing the air gap between the second lens 102 and the third lens 103, shortening the length of the lens, realizing miniaturization, the first lens 101, the second lens 102, the third lens 103 and the fourth lens 104 are all glass lenses, the material of the glass is various types of glass known to those skilled in the art, to ensure that the formed lens has good high-low temperature stability, so that the optical lens can meet the use requirements at different temperatures.

[0030] Embodiment 3

[0031] As Figures 1-4As shown, on the basis of embodiment 1, the utility model provides a technical scheme: preferably, the fifth lens 105 is provided with the pressure ring 107 that fixes the lens to the lens barrel 106 on the side away from the fourth lens 104, the flange plate 108 that fixes the lens to the surface of the optical machine is arranged on the side away from the fifth lens 105 of the pressure ring 107, the distance from the optical axis center of the object plane side surface of the first lens to the image plane is TTL, wherein, 95mm < TTL < 98mm.

[0032] In the embodiment, by reasonably setting the bending degree of the object plane side surface and the image plane side surface in the first lens 101, the second lens 02, the third lens 103 and the fourth lens 104, it is favorable to the structural design of the lens, and the bending direction of the image plane side surface of the second lens 102 and the object plane side surface of the third lens 103 is opposite and the curvature radius is same, which is favorable to realize the miniaturization design of the lens, by reasonably setting the curvature radius of the object plane side surface and the image plane side surface in each lens, the shape of the first lens 101, the second lens 102, the third lens 103 and the fourth lens 104 is influenced, the imaging effect of the lens can be improved, and the near-axis imaging height of the lens is D, wherein, 5.4 < D < 5.6, the near-axis imaging height of the lens is reasonably controlled, the lens can have a larger field angle and target surface size, which is favorable to improve the resolution and ensure the imaging effect of the lens, the effective focal length of the lens is f, 29.7 < f < 30.7, the effective focal length of the lens is reasonably set, the loss of light in each field of view is reduced, the relative luminance of each field of view is improved, and it is favorable to correct the aberration, field curvature and distortion of the lens, thereby ensuring the imaging effect of the lens, the optical total length of the lens can be less than 100mm, the compact structure of the lens is realized, thereby meeting the miniaturization requirement of the lens, the diaphragm 109 is arranged in the light path between the third lens 103 and the fourth lens 104, the propagation direction of the light beam can be adjusted, the light incidence angle is adjusted, which is favorable to improve the imaging quality, the filter is arranged in the light path of the image plane side of the fifth lens 105, the unwanted stray light can be filtered out, thereby improving the image quality of the optical lens, for example, the imaging quality of the optical lens is improved by filtering out infrared light in the daytime through the filter, the chip protection glass is arranged on the image plane side of the filter to protect the photosensitive chip in the optical machine, wherein the photosensitive chip is used to convert the light signal collected by the lens into an electrical signal, thereby ensuring the imaging effect of the lens.

[0033] The working principle of the high-definition and low-distortion projection lens will be described below.

[0034] As Figures 1-4As shown, the dispersion patterns of visible light 0.405 μm under each field of view are relatively concentrated and uniformly distributed, and the dispersion pattern under a certain field of view is not separated from the wavelength, which indicates that there is no obvious purple edge, and the root mean square radius values of visible light 0.405 μm at each field of view of the lens are 0.762 um, 0.738 um, 0.885 um and 1.850 um, respectively, which indicates that the RMS radius of each field of view is less than 2 μm, that is, the lens has low chromatic aberration and aberration under the full field of view, solves the purple edge problem of visible light band imaging, and can realize high-resolution imaging, in the left coordinate system, the horizontal coordinate represents the size of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; wherein T represents meridian, and S represents arc loss; from Figure 3 It can be seen that the lens provided by the embodiment effectively controls the light with a wavelength of 405 nm on the field curvature, that is, the difference between the central image quality and the peripheral image quality is small during imaging; in the right coordinate system, the horizontal coordinate represents the size of the distortion, and the unit is %; the vertical coordinate represents the normalized image height, and there is no unit; from Figure 3 It can be seen that the distortion of the lens provided by the embodiment is well corrected, the imaging distortion is less than 0.015%, the imaging distortion is small, and the low distortion requirement is met, so that the image is not distorted, as shown in Figure 4 As shown, the transfer function of the 100 line pairs / mm in the MTF curve is basically above 0.3, which can meet the image quality requirement and realize high-quality image clarity.

[0035] The above has made a detailed description of the utility model, but some modifications or improvements can be made on the basis of the utility model, which is obvious to those skilled in the art. Therefore, without departing from the spirit of the utility model, the modifications or improvements are within the protection scope of the utility model.

Claims

1. A high-definition and low-distortion projection lens, comprising a first lens (101), a second lens (102), a third lens (103), a fourth lens (104) and a fifth lens (105) arranged in order along an optical axis from an object plane to an image plane, characterized in that: The first lens (101), the second lens (102), the third lens (103), the fourth lens (104) and the fifth lens (105) are all arranged inside a lens barrel (106), a diaphragm (109) is arranged between the third lens (103) and the fourth lens (104), the second lens (102) and the third lens (103) form a cemented lens group, the first lens (101), the second lens (102), the third lens (103) and the fourth lens (104) are all glass spherical lenses, the radius of curvature of the object side surface of the first lens (101) is R11, 30.5mm 2. The high definition and low distortion projection lens of claim 1, wherein: The first lens (101) is a positive focal length lens, the second lens (102) is a positive focal length lens, the third lens (103) is a negative focal length lens, the fourth lens (104) is a positive focal length lens, and the fifth lens (105) is a negative focal length lens, the side of the fifth lens (105) away from the fourth lens (104) is arranged as an image plane, and the side of the first lens (101) away from the second lens (102) is arranged as an object plane.

3. The high definition and low distortion projection lens of claim 1, wherein: The distance from the optical axis center of the object side surface of the first lens (101) to the image plane is TTL, wherein 95mm

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