Low-distortion detection calibration lens

Abstract

The utility model belongs to the technical field of optical lenses, and discloses a low-distortion detection calibration lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along an optical axis from an object side to an image side, the first lens, the third lens, the fourth lens, the sixth lens and the seventh lens have positive focal lengths, and the second lens and the fifth lens have negative focal lengths; the fifth lens and the sixth lens are cemented lenses. The fifth lens and the sixth lens are cemented lenses and can effectively reduce chromatic aberration, the first lens mainly plays a role in correcting distortion, the second lens and the third lens play a role in correcting distortion, data detection is implemented through reasonable matching of positive and negative focal lengths of all the lenses and matching of software, a camera can be used for photographing and center calibration, and the imaging accuracy is improved. The maintenance accuracy is guaranteed, and the device has the advantages of being small in size and convenient to carry.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical lenses, and particularly relates to a low-distortion detection and calibration lens. Background Art

[0002] With the passage of time, there are more and more detection devices on the market, and some detection devices are also increasing day by day. Most of the current detection products on the market are manual detections, and there is no professional equipment to detect the positioning of products. When detecting and repairing, the original positioning parameters are often not found, resulting in troublesome repairs. Content of the Utility Model

[0003] The purpose of the utility model is to provide a low-distortion detection and calibration lens to solve the above problems existing in the prior art.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A low-distortion detection and calibration lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged along the optical axis from the object side to the image side. The first lens, the third lens, the fourth lens, the sixth lens, and the seventh lens have positive focal lengths, and the second lens and the fifth lens have negative focal lengths; the fifth lens and the sixth lens are cemented lenses.

[0006] As a preferred technical solution in the utility model, the first lens, the second lens, and the fifth lens are all made of high-refractive-index materials.

[0007] As a preferred technical solution in the utility model, the sixth lens and the seventh lens are both made of low-dispersion materials.

[0008] As a preferred technical solution in the utility model, a diaphragm is arranged between the fourth lens and the fifth lens.

[0009] As a preferred technical solution in the utility model, the first lens, the fourth lens, the sixth lens, and the seventh lens are all positive lenses, and the second lens, the third lens, and the fifth lens are all negative meniscus lenses.

[0010] As a preferred technical solution in the utility model, the first lens, the second lens, the fifth lens, the sixth lens, and the seventh lens are all glass lenses.

[0011] As a preferred technical solution in the utility model, the total length of the low-distortion detection and calibration lens is 33 - 36 cm.

[0012] Beneficial effects: The present utility model provides a low-distortion detection and calibration lens, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence along the optical axis from the object side to the image side. The first lens, the third lens, the fourth lens, the sixth lens, and the seventh lens have positive focal lengths, and the second lens and the fifth lens have negative focal lengths. The fifth lens and the sixth lens are cemented lenses, which can effectively reduce chromatic aberration. The first lens mainly plays a role in correcting distortion, and the second lens and the third lens play a role in correcting distortion to a certain extent. By reasonably matching the positive and negative focal lengths of each lens and combining software to implement detection data, when detecting whether the four tires of a car are on the same plane, or whether there is an angular deviation between the wheel hub and the bearing, the center can be calibrated by taking pictures with a camera. Thus, it is possible to understand whether the assembly is in place and whether the parameters are qualified through the detection data. When the adjustment is okay, all the data on the display interface will be green, thus ensuring the accuracy of maintenance. It has the functions of small size and convenient carrying. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of the low-distortion detection and calibration lens of the present utility model;

[0014] Figure 2 is an MTF curve graph of the low-distortion detection and calibration lens of the present utility model in the working wavelength range of 700nm - 900nm;

[0015] Figure 3 is a focusing curve graph under an embodiment of the present utility model;

[0016] Figure 4 is a spot diagram of the low-distortion detection and calibration lens of the present utility model;

[0017] Figure 5 is a relative illumination graph of the low-distortion detection and calibration lens of the present utility model.

[0018] In the figure: 1 - first lens; 2 - second lens; 3 - third lens; 4 - fourth lens; 5 - fifth lens; 6 - sixth lens; 7 - seventh lens. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the present utility model in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the drawings is only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. It should be noted here that the description of these embodiments is used to help understand the present utility model, but does not constitute a limitation to the present utility model.

[0020] Embodiment:

[0021] As Figure 1 shown, this embodiment provides a low-distortion detection and calibration lens, which includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7 arranged in sequence along the optical axis from the object side to the image side. The first lens 1, the third lens 3, the fourth lens 4, the sixth lens 6, and the seventh lens 7 have positive focal lengths, and the second lens 2 and the fifth lens 5 have negative focal lengths; the fifth lens 5 and the sixth lens 6 are cemented lenses, which can effectively reduce chromatic aberration. The first lens 1 mainly plays a role in correcting distortion, and the second lens 2 and the third lens 3 play a role in correcting distortion to a certain extent.

[0022] Furthermore, in order to achieve the low-distortion function, the first lens 1, the second lens 2, and the fifth lens 5 in this embodiment are all made of high-refractive-index materials to reduce distortion. Coupled with the cemented lens of the fifth lens 5 and the sixth lens 6, the distortion can be made within 1%.

[0023] Furthermore, in order to achieve no focus shift at high temperature +80°C and low temperature -40°C, the optical power of the positive and negative lenses (the first lens 1, the second lens 2, the third lens 3, and the fifth lens 5, the sixth lens 6) is used inefficiently to achieve focus shift compensation at high and low temperatures. The combination of one negative and one positive compensates for the deformation and refractive index change generated at high and low temperatures.

[0024] Furthermore, in order to achieve a resolution of more than 2 million, through the combination of multiple lenses and cemented lenses, spherical aberration, coma, astigmatism, field curvature and other aberrations can be effectively corrected, thereby improving the resolution quality of the lens. The sixth lens 6 and the seventh lens 7 are both made of low-dispersion materials, which can further optimize spherical aberration and coma, so as to achieve an ideal resolution.

[0025] Furthermore, in order to meet the cost reduction requirement, this case is for the detection of automobile tires, and at the same time, it is in the wavelength band of 700-900nm. When designing, it will be designed according to actual needs. The designed wavelength band is narrow, which can reduce costs. At the same time, the detection method is circular, so there will be vignetting during design, and the image height will become smaller accordingly. At the same time, the structure should consider a very simple way of focusing, that is, screw focusing. The coating uses the wavelength band of 700-900nm, and a single-layer film can solve the problem. The client uses laser supplementary light, so the illuminance of the light source is sufficient, and the relative brightness of the lens can also be improved.

[0026] As a preferred embodiment, a diaphragm is disposed between the fourth lens 4 and the fifth lens 5. The first lens 1, the fourth lens 4, the sixth lens 6, and the seventh lens 7 are all positive lenses, and the second lens 2, the third lens 3, and the fifth lens 5 are all negative meniscus lenses. As the focusing lens of this low-distortion detection and calibration lens, the first lens 1, the second lens 2, the fifth lens 5, the sixth lens 6, and the seventh lens 7 are all glass lenses. In this embodiment, the low-distortion detection and calibration lens of the present invention is a fixed-focus lens, with a focal length between 4.5 and 7, an aperture between 2.5 and 3.2, and a total length between 33 and 36 cm. At the same time, high resolution can be guaranteed; a temperature compensation design is adopted to work in an environment of -40°C to +80°C without defocusing; the mutual compensation of the optical powers of positive and negative lenses not only ensures the performance of the optical system, but also can reduce the processing cost of parts, simplify the structure, reduce the weight, and is also conducive to mass production, meeting the market demand; while using low-dispersion materials, the image quality of the picture can be improved (an optical system is realized through the combination of lenses, mainly achieving clear shooting and a length meeting the requirements of customers). Among them, the relevant parameters of each lens of the low-distortion detection and calibration lens provided by the present invention are shown in the following table:

[0027] Face number Surface type Radius of curvature Thickness / Distance Refractive index Dispersion coefficient S1 Spherical surface 23.57～25.46 1.79～2.01 1.74～1.95 20.79～25.62 S2 Spherical surface -710.5～-715.55 0.03～0.09 S3 Spherical surface 21.19～23.20 0.58～1.25 1.74～1.95 20.79～25.62 S4 Spherical surface 4.00～4.35 2.06～2.56 S5 Spherical surface -22.69～-23.8 5.01～6.01 1.84～2.00 15.94～20.95 S6 Spherical surface -11.52～-13.62 3.20～4.00 S7 Spherical surface 21.28～23.30 3.5～4.5 1.66～1.85 30.17～35.60 S8 Spherical surface -6.37～-6.97 0.65～1.05 STOP Infinity In 0.39～0.68 S10 Spherical surface -4.03～4.23 1.59～2.0 1.74～1.95 20.79～25.62 S11 Spherical surface 5.19～5.69 2.57～3.00 1.50～1.65 54.85～56.9 S12 Spherical surface 5.19～5.69 0.1～0.15 S13 Spherical surface 28.95～30.02 1.56～2.01 1.66～1.85 50.33～55.60 S14 Spherical surface -15.83～17.85 7.56～8.01

[0028] In the above table, S1 and S2 respectively correspond to the two sides of the first lens 1, S3 and S4 respectively correspond to the two sides of the second lens 2, S5 and S6 respectively correspond to the two sides of the third lens 3, S7 and S8 respectively correspond to the two sides of the fourth lens 4, S9 and S10 respectively correspond to the two sides of the fifth lens 5, S11 and S12 respectively correspond to the two sides of the sixth lens 6, and S13 and S14 respectively correspond to the two sides of the seventh lens 7.

[0029] Please refer to Figure 2 and Figure 3 shown, Figure 2 and Figure 3 respectively show the MTF curve graph and the focus curve graph of an embodiment of the low-distortion detection and calibration lens of the present invention in the working wavelength range of 700 nm to 900 nm. It can be seen from Figure 2 and Figure 3 that the low-distortion detection and calibration lens of the present invention has a good focusing effect, can ensure high resolution, and has good imaging quality.

[0030] Please refer to Figure 5 , Figure 5 which shows the relative illumination diagram of an embodiment of the low-distortion detection and calibration lens of the present invention. Among them, the abscissa is the field angle in degrees, and the ordinate is the relative illumination. It can be seen from Figure 4 that the relative illumination of this embodiment reaches more than 80%, and has good relative illumination.

[0031] Finally, it should be noted that the above are only the preferred embodiments of the present utility model and are not intended to limit the protection scope of the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A low-distortion detection and calibration lens, characterized in that: It includes a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), a sixth lens (6) and a seventh lens (7) which are sequentially arranged in the direction from the object side to the image side along the optical axis. The first lens (1), the third lens (3), the fourth lens (4), the sixth lens (6) and the seventh lens (7) have positive focal lengths, and the second lens (2) and the fifth lens (5) have negative focal lengths; the fifth lens (5) and the sixth lens (6) are cemented lenses.

2. The low-distortion detection and calibration lens according to claim 1, characterized in that, The first lens (1), the second lens (2) and the fifth lens (5) are all made of high refractive index materials.

3. The low-distortion detection and calibration lens according to claim 1, characterized in that, The sixth lens (6) and the seventh lens (7) are both made of low dispersion materials.

4. The low-distortion detection and calibration lens according to claim 1, wherein An aperture is arranged between the fourth lens (4) and the fifth lens (5).

5. A low-distortion detection and calibration lens according to claim 1, characterized in that, The first lens (1), the fourth lens (4), the sixth lens (6) and the seventh lens (7) are all positive lenses, and the second lens (2), the third lens (3) and the fifth lens (5) are all negative meniscus lenses.

6. The low-distortion detection and calibration lens according to claim 5, wherein The first lens (1), the second lens (2), the fifth lens (5), the sixth lens (6) and the seventh lens (7) are all glass lenses.

7. A low-distortion detection and calibration lens according to claim 5 or 6, characterized in that The total length of the low distortion detection and calibration lens is 33 - 36 cm.

Images