CN117518422A

CN117518422A - Imaging lens, detection device and detection platform

Info

Publication number: CN117518422A
Application number: CN202210900402.1A
Authority: CN
Inventors: 张倩; 郝希应; 王雁茹
Original assignee: Sunny Optical Zhejiang Research Institute Co Ltd
Current assignee: Sunny Optical Zhejiang Research Institute Co Ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2024-02-06

Abstract

The invention relates to an imaging lens, a detection device and a detection platform, which can realize a diaphragm front lens with large wide angle, high resolution and adjustable diopter, and is convenient for accurately detecting the performance of a virtual display image with a large visual field range. This imaging lens includes arranging in proper order from object side to image side: a front diaphragm, a front lens group, a movable lens group, a relay lens front group and a relay lens rear group, wherein the movable lens group is arranged in a light path between the front lens group and the relay lens front group in a back-and-forth movable way; the focal length of the front lens group is larger than 19mm and smaller than 30mm, the focal length of the movable lens group is larger than 650mm or smaller than-650 mm, the focal length of the relay lens front group is larger than or equal to the focal length of the relay lens rear group, and the air interval between the relay lens front group and the relay lens rear group is larger than 30mm.

Description

Imaging lens, detection device and detection platform

Technical Field

The present invention relates to the field of optical imaging technologies, and in particular, to an imaging lens, a detection device, and a detection platform.

Background

With the rapid enhancement of applications of augmented reality/virtual reality (AR/VR) devices in gaming, military, educational, traffic, and medical industries, there is an increasing need to measure various types of AR/VR display images. In general, for the experience of a display screen, if visual perception is only performed by human eyes as evaluation, the evaluation result varies from person to person, and is naturally unavoidable. Therefore, it is important to objectively and quantitatively characterize, accurately measure and evaluate the display performance of the near-eye display device, so that effective detection of virtual image displays such as the near-eye display device is an emerging requirement.

In the existing detection device, the diaphragm of the lens is usually built in, so that the distance between the entrance pupil position of the lens and the exit pupil of the near-eye display device is too far, matching of the eye boxes is difficult to realize, and then field vignetting can occur in the detection process, and even light rays with a large field angle cannot be collected. In addition, when measuring display images over a wide field of view, existing detection devices typically have a specific working distance, i.e. only display images at a certain distance can be clearly focused and measured; therefore, when the range of the object distance change is large, the existing detection equipment cannot be used for clear focusing, and measurement is affected.

Disclosure of Invention

One advantage of the present invention is to provide an imaging lens, a detection device and a detection platform, which can realize a large wide angle, high resolution, diopter adjustable diaphragm front lens, and facilitate accurate performance detection of virtual display images with large field of view.

Another advantage of the present invention is to provide an imaging lens, a detecting device, and a detecting platform, wherein in an embodiment of the present invention, the imaging lens can implement a wide angle, a large target surface, and a large aperture while making a diaphragm front, so as to accurately reproduce the position of human eyes in a near-eye display device.

Another advantage of the present invention is to provide an imaging lens, a detection device, and a detection platform, wherein in an embodiment of the present invention, the detection device can implement pixel level detection, has controllable cost and stable performance, and can implement more stable imaging and photochromic detection of a display image in a temperature range of-30 ℃ to 100 ℃.

Another advantage of the present invention is to provide an imaging lens, a detection device, and a detection platform, in which expensive materials or complex structures are not required in the present invention in order to achieve the above-described object. The present invention thus successfully and efficiently provides a solution that not only provides a simple imaging lens, detection device and detection platform, but also increases the practicality and reliability of the imaging lens, detection device and detection platform.

To achieve at least one of the above or other advantages and objects of the present invention, there is provided an imaging lens including, in order from an object side to an image side: a front diaphragm, a front lens group, a movable lens group, a relay lens front group and a relay lens rear group, wherein the movable lens group is arranged in a light path between the front lens group and the relay lens front group in a back-and-forth movable manner; the focal length of the front lens group is larger than 19mm and smaller than 30mm, the focal length of the movable lens group is larger than 650mm or smaller than-650 mm, the focal length of the relay lens front group is larger than or equal to the focal length of the relay lens rear group, and the air interval between the relay lens front group and the relay lens rear group is larger than 30mm.

According to one embodiment of the application, the focal length of the front group of the relay lens is greater than 62mm and less than 135mm, and the focal length of the rear group of the relay lens is greater than 40mm and less than 64mm.

According to one embodiment of the application, the back focal length of the imaging lens is greater than or equal to 60mm, and the ratio of the total optical length to the optical image height of the imaging lens is greater than 8.5 and less than 14.

According to one embodiment of the present application, the imaging lens further includes a field stop disposed at an intermediate real image plane position between the front lens group and the movable lens group.

According to one embodiment of the present application, the front lens group is composed of a first positive lens, a second positive lens, a third positive lens and a first double cemented lens which are sequentially arranged from an object side to an image side, wherein the optical powers of the first positive lens, the second positive lens and the third positive lens are sequentially increased.

According to one embodiment of the present application, the first positive lens, the second positive lens and the third positive lens are all positive meniscus lenses.

According to one embodiment of the present application, the front lens group is composed of a positive cemented lens, a second positive lens, a third positive lens, and a first cemented doublet, which are sequentially arranged from the object side to the image side, wherein the powers of the positive cemented lens, the second positive lens, and the third positive lens sequentially increase.

According to one embodiment of the application, the first double-cemented lens group is formed by a first lens and a second lens, the refractive index of the first lens is smaller than 1.54, and the Abbe number of the first lens is larger than 80; the refractive index of the second lens is greater than 1.82, and the Abbe number of the second lens is greater than 22.

According to one embodiment of the present application, the movable lens group is a second double cemented lens.

According to one embodiment of the present application, the relay lens front group is composed of a first positive lens group, a first negative lens group, and a second positive lens group arranged in order from an object side to an image side.

According to one embodiment of the present application, the relay lens rear group is composed of a plurality of lenses, wherein a lens closest to an image side in the relay lens rear group is a positive lens.

According to one embodiment of the application, two lenses of the relay lens rear group close to the object side are cemented to form a cemented doublet.

According to one embodiment of the application, the lens close to the object side in the relay lens rear group is arranged eccentrically adjustable for compensating lens coma by eccentric adjustment.

According to one embodiment of the present application, the refractive index of the lens having positive optical power in the imaging lens is larger than the refractive index of the lens having negative optical power.

According to another aspect of the present application, there is further provided a detection apparatus including:

any one of the above imaging lenses;

an image sensor disposed on an image side of the imaging lens; and

and a filter member disposed in an optical path between the imaging lens and the image sensor.

According to one embodiment of the application, the optical filter is an XYZ optical filter set, and the XYZ optical filter set is rotatably disposed on a photosensitive side of the image sensor and is used for being driven so that different optical filters in the XYZ optical filter set sequentially cover a photosensitive surface of the image sensor.

According to another aspect of the present application, the present application further provides an inspection platform, including:

the detection device;

the detection tool is arranged on the detection side of the detection device and is used for placing equipment to be detected; and

the industrial personal computer is communicatively connected with the detection tool and used for controlling the device to be detected placed on the detection tool to display a virtual image; the industrial personal computer is communicably connected to the detection device and is used for controlling the detection device to collect virtual images displayed by the equipment to be detected, and performing image processing on the collected virtual image information to output a detection result

Drawings

FIG. 1 is a block diagram of a detection device according to one embodiment of the present invention;

fig. 2 shows a first example of a detection device according to the above-described embodiment of the present invention;

fig. 3 shows a schematic optical path of a detection device according to the first example of the present invention;

fig. 4A shows a schematic diagram of an optical transfer function (MTF) curve of the detection apparatus according to the first example of the present invention at an object distance of infinity;

FIG. 4B shows a schematic diagram of an optical transfer function (MTF) curve of the detection apparatus according to the first example of the present invention at an object distance of 250 mm;

fig. 5A shows a schematic diagram of a field curvature of a detection device according to the first example of the present invention;

fig. 5B shows a distortion schematic diagram of the detection apparatus according to the above first example of the present invention;

FIG. 6A is a diagram showing the statistics of Monte Carlo yield before improvement of the first example of the detecting apparatus according to the present invention;

FIG. 6B is a diagram showing the improved Monte Carlo yield statistics of the detection apparatus according to the first example of the present invention;

fig. 7 shows a second example of the detection apparatus according to the above-described embodiment of the present invention;

fig. 8 shows a third example of the detection apparatus according to the above-described embodiment of the present invention;

fig. 9 is a block diagram schematic of an inspection platform according to one embodiment of the present application.

Description of the reference numerals: 1. a detection device; 10. an imaging lens; 11. a front diaphragm; 12. a front lens group; 121. a first positive lens; 122. a second positive lens; 123. a third positive lens; 124. a first doublet lens; 1241. a first lens; 1242. a second lens; 125. a positive cemented lens; 13. a movable lens group; 130. a second double cemented lens; 14. a relay lens front group; 141. a first positive lens group; 142. a first negative lens group; 143. a second positive lens group; 15. a relay lens rear group; 151. a first relay lens; 152. a second relay lens; 153. a third relay lens; 154. a fourth relay lens; 155. a fifth relay lens; 156. a sixth relay lens; 157. a seventh relay lens; 158. an eighth relay lens; 16. a field stop; 20. an image sensor; 30. a light filter; 31. an XYZ filter set; 40. detecting a tool; 50. and the industrial personal computer.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It is noted that when an element is referred to as being "disposed" or "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

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 herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or/and" as used herein includes any and all combinations of one or more of the associated listed items.

Considering that the prior optical lens has too far entrance pupil position of the lens and the exit pupil distance of the near-eye display device due to the built-in diaphragm, the matching of the eye boxes is difficult to realize, and on the other hand, when the display image with a wide field of view is measured, the display image with a certain distance can be focused and measured clearly, so that when the object distance change range is large, the clear focusing cannot be performed often, and the measurement is influenced. In order to solve the above problems, the application provides an imaging lens, a detection device and a detection platform, which can realize a diaphragm front lens with wide angle, high resolution and adjustable diopter, and is convenient for accurately detecting the performance of a virtual display image with a large visual field range.

Specifically, referring to fig. 1 to 8, an embodiment of the present invention provides a detection apparatus 1 for detecting image display performance of various display devices. The detection device 1 may include an imaging lens 10, an image sensor 20 disposed on an image side of the imaging lens 10, and a filter 30 disposed in an optical path between the imaging lens 10 and the image sensor 20, so that image light to be detected passes through the imaging lens 10 to be modulated to be imaged, and is then received by the image sensor 20 after being filtered through the filter 30 to obtain image detection information, thereby realizing detection of image display performance.

More specifically, as shown in fig. 1 and 2, the imaging lens 10 may include a front stop 11, a front lens group 12, a movable lens group 13, a relay lens front group 14, and a relay lens rear group 15 arranged in order from an object side to an image side, the movable lens group 13 being disposed in a light path between the front lens group 12 and the relay lens front group 14 so as to be movable back and forth. The focal length of the front lens group 12 is larger than 19mm and smaller than 30mm, the focal length of the movable lens group 13 is larger than 650mm or smaller than-650 mm, the focal length of the relay lens front group 14 is larger than or equal to the focal length of the relay lens rear group 15, and the air interval between the relay lens front group 14 and the relay lens rear group 15 is larger than 30mm.

It should be noted that, in the imaging lens 10 of the present application, the front stop 11 is located at the object side (front) of the front lens assembly 12, and the focal length of the front lens assembly 12 is smaller than 30mm, so that the light rays with the angle of view within 146 degrees can be collected and converged, so that the light rays reach the desired height, and the angle at the middle real image plane position is gentle and close to telecentricity; since the movable lens group 13 in the imaging lens 10 can move back and forth between the front lens group 12 and the relay lens front group 14 and the focal length absolute value of the movable lens group 13 is greater than 650mm, the imaging lens 10 can achieve continuous clear and stable focusing and imaging in an object space in the range of 0 to 4D. In addition, the focal length of the front relay lens group 14 is larger than that of the rear relay lens group 15, the air interval between the front relay lens group 14 and the rear relay lens group 15 is larger than 30mm, and the image light to be detected can be quickly collected and converged to reach the target receiving surface after passing through the rear relay lens group 15; here, the transition between the front relay lens group 14 and the rear relay lens group 15 is performed by adopting a longer air interval (greater than 30 mm), so that the transition condition of light can be effectively adjusted, the light trend between the front relay lens group and the rear relay lens group is smoothed, the sensitivity of the system is improved, the degree of freedom of aberration correction of the system is increased, and good, stable and controllable imaging performance is obtained, so that engineering implementation is facilitated.

Optionally, the focal length of the relay lens front group 14 is greater than 62mm and less than 135mm, and the focal length of the relay lens rear group 15 is greater than 40mm and less than 64mm.

According to the above embodiment of the present application, as shown in fig. 2, the optical filter 30 may be implemented as an XYZ optical filter set 31, where the XYZ optical filter set 31 is rotatably disposed on the photosensitive side of the image sensor 20, and is used to be driven to sequentially cover different optical filters in the XYZ optical filter set 31 on the photosensitive surface of the image sensor 20, so as to obtain the brightness and chromaticity information related to the target, so as to measure the imaging quality of the display image, and measure the brightness and chromaticity at the same time, so as to provide measurement data to measure the absolute brightness or color of the human eye visualized in the display device, and further objectively perform quantitative characterization and accurate measurement and evaluation on the display performance of the display device. It will be appreciated that the XYZ filter set 31 may be driven by a motor to rotate so that the various filters sequentially cover the surface of the image sensor 20.

Optionally, the back focal length of the imaging lens 10 is 60mm or more; the ratio of the total optical length TTL to the optical image height IMY of the imaging lens 10 is greater than 8.5 and less than 14.

Optionally, as shown in fig. 2 and 3, the imaging lens 10 further includes a field stop 16, the field stop 16 being disposed at an intermediate real image plane position between the front lens group 12 and the movable lens group 13 for improving flare of the system.

Preferably, the field stop 16 is implemented as an iris for intercepting the field range of the front collected onto the intermediate real image plane to determine the intercepted field range by the opening and closing degree thereof. For example, when the field stop 16 is fully open, light rays of the full field range (146 degrees) are transmitted to the image sensor 20.

Optionally, the refractive index of the lens with positive power in the imaging lens 10 is greater than the refractive index of the lens with negative power in order to improve and balance the system curvature of field. It can be understood that under the limitation of the effective length and caliber of the system, the high-refraction material is effectively selected for the lens with positive focal power in the system, and the low-refraction material is selected as much as possible for the lens with negative focal power in the system, thereby being beneficial to improving and balancing the field curvature of the system.

Optionally, the surface of each lens in the imaging lens 10 is provided with an antireflection film or an antireflection coating, so as to reduce stray light or ghost images and achieve an optical effect with higher contrast. It is understood that the anti-reflection film or the anti-reflection coating may have high transmittance over a wide wavelength range.

It should be noted that the technical indexes of the imaging lens 10 of the present application may be, but are not limited to, implemented as: the focal length of the lens is-11 mm; the aperture of the front diaphragm 11 is between 1mm and 5 mm; working distance from 0.25m to infinity; the angle of view is 146 °; the applicable spectrum range is between 400nm and 700 nm; the central field of view MTF is greater than 0.5@160lp/mm; the edge view field MTF is greater than 0.2@120lp/mm; the total optical length is less than or equal to 400mm; the maximum lens diameter is 59mm; the imaging target size was 29mm.

Illustratively, in the first example of the present application, as shown in fig. 2 and 3, the front lens group 12 may be composed of a first positive lens 121, a second positive lens 122, a third positive lens 123, and a first doublet 124 arranged in order from the object side to the image side, wherein the powers of the first positive lens 121, the second positive lens 122, and the third positive lens 123 are sequentially increased so as to take on the light ray deflection angle with a strong positive power lens, and achromatism is performed by the first doublet 124 to effectively improve the chromatic dispersion problem.

Alternatively, the first positive lens 121, the second positive lens 122, and the third positive lens 123 are implemented as positive meniscus lenses having a high refractive index. It can be understood that, although three positive meniscus lenses with high refractive index are used continuously in the imaging lens 10 of the present application, the light rays with large viewing angles of ±73° can be collected into the front lens group rapidly, but larger chromatic aberration is introduced at the same time; in order to improve the chromatic aberration, the imaging lens 10 of the present application is corrected by the following double cemented lens, so that the angle of the light ray at the intermediate real image plane position collected and transmitted through the front lens group 12 is gentle, and the near telecentricity helps to improve the system flare through the field stop 16.

Alternatively, as shown in fig. 2 and 3, the first doublet 124 of the front lens group 12 may be cemented by a first lens 1241 and a second lens 1242, the first lens 1241 having a refractive index (Nd) _L4 Less than 1.54, an Abbe number (Vd) of the first lens 1241 _L4 Greater than 80; refractive index (Nd) of the second lens 1242 _L5 Greater than 1.82, an Abbe number (Vd) of the second lens 1242 _L5 Greater than 22.

Optionally, as shown in fig. 2 and 3, the movable lens group 13 may be implemented as a second double cemented lens 130 to further improve chromatic aberration while achieving clear focusing in the entire 0 to 4D spatial range, and to more smoothly transition light rays having a higher position after passing through the front lens group 12 to the subsequent relay lens front group 14 to reduce sensitivity of the movable lens group 13, improve fit tolerances between the movable lens group 13 and the lens barrel, and thus relieve pressure of structural assembly and processing.

Alternatively, as shown in fig. 2 and 3, the relay lens front group 14 may be composed of a first positive lens group 141, a first negative lens group 142, and a second positive lens group 143 arranged in order from the object side to the image side, so as to rapidly realize that the heights of the light rays passing through the front stop 11, the front lens group 12, the movable lens group 13, and the relay lens front group 14 undergo a low-to-high-re-decrease change process, thereby effectively improving and correcting the system curvature of field. It can be understood that, for the optical system with a wide angle and a large aperture, field curvature is a key to limit the improvement of the image quality of the lens, and because of the system with a large field curvature pressure, the alternating and transitional structural modes of high and low light rays can effectively balance the field curvature of the system, so as shown in fig. 3, the relay lens front group 14 of the present application adopts the combination of the positive lens group, the negative lens group and the positive lens group, and can rapidly reduce the light ray height after the front lens group 12 and the movable lens group 13, thereby presenting the change process of the light ray height from low to high to low, and being beneficial to the correction of the field curvature of the system.

Alternatively, the first positive lens group 141 in the relay lens front group 14 may be implemented as, but is not limited to, a cemented doublet; the first negative lens group 142 may be composed of, but is not limited to, two lenses; the second positive lens group 143 may be composed of, but not limited to, three lenses. In other words, the relay lens front group 14 is composed of seven lenses.

Alternatively, the relay lens rear group 15 may be composed of a plurality of lenses, wherein the lens closest to the image side (i.e., closest to the image sensor 20) in the relay lens rear group 15 is a positive lens. For example, as shown in fig. 2 and 3, the relay lens rear group 15 may be composed of a first relay lens 151, a second relay lens 152, a third relay lens 153, a fourth relay lens 154, a fifth relay lens 155, a sixth relay lens 156, a seventh relay lens 157, and an eighth relay lens 158 arranged in order from the object side to the image side, wherein the eighth relay lens 158 is a positive lens. It can be appreciated that the surfaces of the first lenses (e.g., the first, second, third, fourth, fifth and so on) in the relay lens back group 15 are located at a lower light height so as to form a transition between high and low light again, which is beneficial to correcting the curvature of field of the system and balancing the light transmitted by the sixth relay lens 156, the seventh relay lens 157 and the eighth relay lens 158, and then finally converging to the target image, so as to form a transition and cooperation between high and low light again.

Alternatively, two lenses near the object side in the relay lens rear group 15 are cemented to form a cemented doublet. For example, the first relay lens 151 and the second relay lens 152 are cemented to form a cemented doublet.

Specifically, in the above-described first example of the present application, all lenses in the imaging lens 10 are implemented as full-glass spherical lenses, and a 22G architecture is employed. The detection device 1 sequentially sets structural imaging parameters of each functional surface from an object side to an image side: the surface Type, the radius of curvature R, the center thickness Tc, the refractive index Nd, and the abbe number Vd are as shown in table 1 below, wherein when the imaging lens 10 is clearly focused at an infinite working distance, an air interval t1=19.89 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air interval t2=0.2 mm between the movable lens group 13 and the relay lens front group 14; when the imaging lens 10 is clearly focused at a working distance of 250mm, an air space t1=8 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air space t2=12.09 mm between the movable lens group 13 and the relay lens front group 14.

Table 1: structural parameter table of detection device

It will be appreciated that in table 1 above: infinicity means infinite, e.g., radius of curvature Infinicity means that the current face is a plane; the center thickness Tc represents the distance from the front face to the adjacent face; the refractive index and abbe number represent the medium data between the front and the next.

Further, by testing this detection device 1 of the first example described above, it is possible to obtain: the optical transfer function (MTF) curve of the detection device 1 at an object distance of infinity as shown in fig. 4A; an optical transfer function (MTF) curve of the detection device 1 at an object distance of 250mm as shown in fig. 4B; a field diagram and a distortion diagram of the detection device 1 as shown in fig. 5A and 5B.

As can be seen from fig. 5B: the f-theta distortion of the imaging lens 10 of the detection device 1 is smaller than 1%, and the f-theta distortion is adopted for control and evaluation, so that the linear mapping relation between the incident light of different angles of view and the image surface size is conveniently realized, and the measurement rule is more met.

It should be noted that, for lens structures with a large number of lenses, how to achieve the required matching accuracy between lenses, that is, the assurance of tolerance yield corresponding to the system is a key difficulty, the imaging lens 10 of the present application can not only optimize the sensitivity of a part of sensitive elements of the system, but also effectively improve the system tolerance by properly adding some adjustment compensation amounts, for example, increasing the adjustment of the critical air gap can compensate the spherical aberration of the system or increasing the eccentric adjustment of a part of the critical elements can compensate the coma aberration of the system.

Specifically, the lens near the object side in the relay lens rear group 15 of the imaging lens 10 is disposed eccentrically adjustable for compensating for lens coma by eccentric adjustment to improve the system yield. For example, the first relay lens 151 and the second relay lens 152 are eccentrically and adjustably disposed in the optical path between the relay lens front group 14 and the third relay lens 153, so that the eccentric adjustment of the first relay lens 151 and the second relay lens 152 glued together is used as a compensation amount, which contributes to the significant improvement and improvement of the overall yield of the system.

Illustratively, by test analysis it is known that: before decentering adjustment by the first relay lens 151 and the second relay lens 152, i.e., before yield improvement, a statistical chart of the monte carlo yield of the imaging lens 10 is shown in fig. 6A; and after decentering adjustment of the first relay lens 151 and the second relay lens 152, i.e. after improvement of the yield, the statistical chart of the monte carlo yield of the imaging lens 10 is shown in fig. 6B.

It should be noted that, in the second example of the present application, as shown in fig. 7, all lenses in the imaging lens 10 are implemented as full glass spherical lenses, and a 21G architecture is adopted. The imaging lens 10 according to the second example of the present application is different from the above-described first example according to the present application in that: the first positive lens 121 of the front lens group 12 is replaced by a positive cemented lens 125; the relay lens front group 14 is composed of six lenses; the relay lens rear group 15 is composed of seven relay lenses.

The detection device 1 sequentially sets structural imaging parameters of each functional surface from an object side to an image side: the surface Type, the radius of curvature R, the center thickness Tc, the refractive index Nd, and the abbe number Vd are as shown in table 2 below, wherein when the imaging lens 10 is clearly focused at an infinite working distance, an air interval t1=2.54 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air interval t2=37.46 mm between the movable lens group 13 and the relay lens front group 14; when the imaging lens 10 is clearly focused at a working distance of 250mm, an air space t1=28.24 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air space t2=11.76 mm between the movable lens group 13 and the relay lens front group 14.

Table 2: structural parameter table of detection device

It should be noted that, in the third example of the present application, as shown in fig. 8, all lenses in the imaging lens 10 are implemented as full glass spherical lenses, and a 20G architecture is adopted. The imaging lens 10 according to the third example of the present application is different from the above-described first example according to the present application in that: the relay lens rear group 15 is composed of six relay lenses.

The detection device 1 sequentially sets structural imaging parameters of each functional surface from an object side to an image side: the surface Type, the radius of curvature R, the center thickness Tc, the refractive index Nd, and the abbe number Vd are as shown in table 2 below, wherein when the imaging lens 10 is in clear focus at an infinite working distance, an air gap t1=11 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air gap t2=8 mm between the movable lens group 13 and the relay lens front group 14; when the imaging lens 10 is clearly focused at a working distance of 250mm, an air space t1=5.33 mm between the movable lens group 13 and the front lens group 12 in the imaging lens 10, and an air space t2=13.67 mm between the movable lens group 13 and the relay lens front group 14.

Table 3: structural parameter table of detection device

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In summary, through the test verification of the above three examples, the present application provides an imaging lens with a large wide angle, high resolution and adjustable diopter with a front aperture, so as to form a detection device together with a color filter and an image sensor (such as a photo detector). Meanwhile, the XYZ color filter combination is rotated by a driving mechanism such as a motor to sequentially cover the surface of the light detector, so that the brightness and chromaticity information related to the target is obtained, and the imaging quality and brightness information of the display image are measured. In addition, the imaging lens supports clear focusing under the whole working distance from 250mm to infinity while supporting the measurement of the display image with the ultra-large view field, and can basically meet the measurement requirements of most AR and VR equipment display images at present.

In other words, the large wide-angle and high-resolution imaging lens with the front-mounted diaphragm can mainly realize accurate performance detection on virtual display images with a large visual field range. The main advantages include: the imaging lens is provided with a diaphragm in front, can accurately replicate the position of human eyes in AR/VR equipment, enables captured display images not to be blocked and interfered by any, is provided with an iris diaphragm in front, can be adjusted in size (for example, 1-5 mm), and can effectively control the light incoming quantity. Meanwhile, the imaging lens has a large-range diopter adjusting function, can realize clear imaging in a range of 0-4D (0.25 m-infinity) so as to be compatible with image detection of near-eye display equipment with adjustable diopter; in order to realize the linear mapping relation between the incident light of different angles and the image plane, the f-theta distortion of the detection lens is less than 1%, and the detection lens is more in line with the measurement rule. That is, the imaging lens of the present application has sufficient resolution to capture all details in the display image, enabling pixel level detection; the lens is formed into a full spherical lens, has controllable cost and stable performance, and can realize more stable imaging and photochromic detection of a display image within the temperature range of-30 ℃ to 100 ℃.

It is noted that, according to the above-described embodiment of the present application, the detecting device 1 may further include a focus control device (not shown in the drawings) for controlling the focusing operation of the imaging lens 10. For example, the focus control device may be, but not limited to, implemented as a voice coil motor, etc., which will not be described in detail herein.

It should be noted that, according to another aspect of the present application, as shown in fig. 9, an embodiment of the present application provides a detection platform, which may include the above-mentioned detection device 1, the detection tool 40, and the industrial personal computer 50. The detection tool 40 is disposed on the detection side of the detection device 1, and is used for placing a device to be detected. The industrial personal computer 50 is communicatively connected to the detection tool 40, and is used for controlling the device to be detected to display a virtual image; the industrial personal computer 50 is communicatively connected to the detecting device 1, and is configured to control the detecting device 1 to collect a virtual image displayed by the device under test, and perform image processing on the collected virtual image information to output a detection result.

It will be appreciated that the industrial personal computer 50 of the present application may be implemented as a PC-side processor, which may combine with software algorithms to provide the detection platform with the following measurement items and auxiliary functions: automatic focusing; detecting the resolving power; brightness and uniformity measurements; measuring chromaticity; measuring the contrast of a chessboard; calibrating a virtual image distance; calibrating lens distortion; generating and switching a test image; and outputting a detection result.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as 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

1. Imaging lens, its characterized in that includes arranging from object side to image side in proper order: a front diaphragm, a front lens group, a movable lens group, a relay lens front group and a relay lens rear group, wherein the movable lens group is arranged in a light path between the front lens group and the relay lens front group in a back-and-forth movable manner; the focal length of the front lens group is larger than 19mm and smaller than 30mm, the focal length of the movable lens group is larger than 650mm or smaller than-650 mm, the focal length of the relay lens front group is larger than or equal to the focal length of the relay lens rear group, and the air interval between the relay lens front group and the relay lens rear group is larger than 30mm.

2. The imaging lens of claim 1, wherein a focal length of the relay lens front group is greater than 62mm and less than 135mm, and a focal length of the relay lens rear group is greater than 40mm and less than 64mm.

3. The imaging lens as claimed in claim 1, wherein a back focal length of the imaging lens is 60mm or more, and a ratio of an optical total length to an optical image height of the imaging lens is greater than 8.5 and less than 14.

4. The imaging lens of claim 1, further comprising a field stop disposed at an intermediate real image plane position between the front lens group and the movable lens group.

5. The imaging lens according to claim 1, wherein the front lens group is composed of a first positive lens, a second positive lens, a third positive lens, and a first doublet lens arranged in order from an object side to an image side, wherein optical powers of the first positive lens, the second positive lens, and the third positive lens are sequentially increased.

6. The imaging lens of claim 5, wherein the first positive lens, the second positive lens, and the third positive lens are positive meniscus lenses.

7. The imaging lens according to claim 1, wherein the front lens group is composed of a positive cemented lens, a second positive lens, a third positive lens, and a first cemented doublet arranged in order from an object side to an image side, wherein optical powers of the positive cemented lens, the second positive lens, and the third positive lens are sequentially increased.

8. The imaging lens according to any one of claims 5 to 7, wherein the first double cemented lens group is formed by a first lens and a second lens, a refractive index of the first lens is less than 1.54, and an abbe number of the first lens is greater than 80; the refractive index of the second lens is greater than 1.82, and the Abbe number of the second lens is greater than 22.

9. The imaging lens of claim 1, wherein the movable lens group is a second double cemented lens.

10. The imaging lens according to claim 1, wherein the relay lens front group is composed of a first positive lens group, a first negative lens group, and a second positive lens group arranged in order from an object side to an image side.

11. The imaging lens according to claim 1, wherein the relay lens rear group is composed of a plurality of lenses, wherein a lens closest to an image side in the relay lens rear group is a positive lens.

12. The imaging lens as claimed in claim 11, wherein two lenses close to the object side in the relay lens rear group are cemented to form a cemented doublet.

13. The imaging lens according to claim 12, wherein a lens near an object side in the relay lens rear group is eccentrically adjustably disposed for compensating for lens coma by eccentric adjustment.

14. The imaging lens according to any one of claims 1 to 7, wherein a refractive index of a lens having positive optical power in the imaging lens is larger than a refractive index of a lens having negative optical power.

15. Detection device, characterized in that includes:

the imaging lens as claimed in any one of claims 1 to 14;

an image sensor disposed on an image side of the imaging lens; and

16. The apparatus according to claim 15, wherein the filter is an XYZ filter set rotatably disposed on a photosensitive side of the image sensor, for being driven so that different filters in the XYZ filter set sequentially cover a photosensitive surface of the image sensor.

17. Detection platform, its characterized in that includes:

the detection device of claim 15;

the industrial personal computer is communicatively connected with the detection tool and used for controlling the device to be detected placed on the detection tool to display a virtual image; the industrial personal computer is communicably connected to the detection device and is used for controlling the detection device to collect virtual images displayed by the equipment to be detected and processing the collected virtual image information to output detection results.