An ultra-low-distortion high-resolution industrial lens

Abstract

The application belongs to the technical field of optical imaging equipment, and provides an ultra-low-distortion high-resolution industrial lens. The ultra-low-distortion high-resolution industrial lens comprises a lens barrel body, and a negative focal length front lens group, a negative focal length middle focusing group and a positive focal length rear lens group are sequentially arranged in the lens barrel body from an object side to an image side. Compared with the prior art, the ultra-low-distortion high-resolution industrial lens is more convenient to install in a machine vision device by adopting a miniaturized compact structure design; by matching different focal length lenses, adopting an ultra-low-distortion design technology and a 400-1000 nm wide spectrum, distortion causing image processing difficulty is completely corrected, picture distortion is maximally inhibited, light reflection loss of the lens is effectively reduced, glare is reduced, contrast is increased, color restoration is improved, so that the image effect is more truly reflected, and the image clarity is improved.

Description

Technical Field

[0001] This invention relates to the fields of optical imaging equipment technology and optoelectronic display technology, specifically to an ultra-low distortion high-resolution industrial lens for machine vision equipment. Background Technology

[0002] With the rapid development of technology, the machine vision industry, along with the strong rise of the manufacturing sector, has received widespread attention and extensive industrial applications across various industries. Machine vision has now become one of the core key elements for achieving industrial automation and intelligence.

[0003] The lens is the eye of machine vision, playing this role from the moment it begins inspecting objects, providing feedback to the industrial camera. Distortion in machine vision lenses is image distortion caused by inconsistent magnification within the field of view. Due to manufacturing processes, lens distortion is unavoidable; the better the lens, the less distortion. For ordinary optical lenses, this imaging defect can be ignored as long as the distortion is imperceptible. However, for applications that use images to determine object size, distortion is crucial, directly affecting measurement accuracy. Therefore, in precision measurement systems and other applications requiring high precision, machine vision lens distortion must be considered. The distortion of ordinary industrial lenses is typically 1%-2%, which usually affects detection accuracy and, consequently, the overall performance of the vision system. Therefore, industrial lenses with ultra-low distortion and high-performance resolution have a broad market prospect. These lenses can more realistically reflect image effects, improve color reproduction, and enhance image clarity. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention provides an ultra-low distortion high-resolution industrial lens that can achieve miniaturization, large field of view, high relative illumination, good uniformity, small close-up distance, and high imaging quality with a resolution of up to five million pixels.

[0005] To achieve its purpose, the technical solution adopted by this invention is: an ultra-low distortion, high-resolution industrial lens, comprising a lens barrel body, wherein from the object side to the image side, a negative optical power front lens group, a negative optical power central focusing group, and a positive optical power rear lens group are arranged sequentially. The negative optical power front lens group is composed of a positive optical power first lens, a negative optical power second lens, a negative optical power third lens, and a negative optical power fourth lens; the negative optical power central focusing group is composed of a negative optical power fifth lens; and the positive optical power rear lens group is composed of a positive optical power sixth lens, a positive optical power seventh lens, a negative optical power eighth lens, a positive optical power ninth lens, and a negative optical power tenth lens forming a cemented triplet lens, an eleventh positive optical power lens, and a twelfth positive optical power lens.

[0006] The positive optical power first lens is a meniscus lens, and the positive optical power first lens is fixed in the lens barrel body by an inner pressure ring; the negative optical power second lens is a meniscus lens, and a first spacer is installed between the positive optical power first lens and the negative optical power second lens.

[0007] Both the negative optical power third lens and the negative optical power fourth lens are meniscus lenses. The negative optical power second lens and the negative optical power third lens are directly connected, and the negative optical power third lens and the negative optical power fourth lens are also directly connected.

[0008] The negative optical power fifth lens is a meniscus lens. The negative optical power fifth lens is fixed in the lens barrel body by a sleeve and an inner pressure ring, and is connected to the external focusing ring by a focusing screw.

[0009] The sixth lens with positive optical power is a biconvex lens, and the sixth lens with positive optical power is fixed in the lens barrel body by an inner pressure ring; the seventh lens with positive optical power is a biconvex lens, and the seventh lens with positive optical power is fixed in the lens barrel body by an inner pressure ring; a manual aperture module is provided between the sixth lens with positive optical power and the seventh lens with positive optical power.

[0010] The negative optical power eighth lens, together with the positive optical power ninth lens and the negative optical power tenth lens, form a cemented triplet lens, and a second spacer is installed between the cemented triplet lens and the positive optical power eleventh lens.

[0011] The eleventh and twelfth positive power lenses are biconvex lenses. A third spacer is installed between the eleventh and twelfth positive power lenses. The twelfth positive power lens is fixed in the lens barrel body by an external pressure ring.

[0012] The beneficial effects of this invention are as follows: This invention provides an ultra-low distortion, high-resolution industrial lens with manual aperture adjustment and manual focus, capable of close-up effects from infinity to 0.1 meters, with an effective focal length f = 8mm, a maximum relative aperture number F / # = 1.5, a total optical system length of less than 70mm, an image size of 2 / 3 inch, a resolution of 5 megapixels, a full field-of-view resolution of up to 140lp / mm, good image uniformity, a peripheral to center illumination ratio of over 70%, and ultra-low distortion, with a total distortion rate of less than 1%. Compared with existing technologies, this ultra-low distortion high-resolution industrial lens solution adopts a miniaturized and compact structural design, making it easier to install in machine vision equipment. By combining lenses of different optical powers, using ultra-low distortion design technology and a wide 400-1000nm spectrum, it completely corrects the distortion that causes difficulties in image processing, suppresses image distortion to the greatest extent, effectively reduces lens reflection loss, reduces glare, increases contrast, and improves color reproduction, thereby reflecting the image effect more realistically and improving image clarity. Attached Figure Description

[0013] Figure 1 A schematic diagram of the overall structure created by this invention;

[0014] Figure 2 A schematic diagram of the optical system structure is provided for this invention;

[0015] Figure 3 This invention provides a schematic diagram of the MTF (Modulation Transfer Function).

[0016] Figure 4 This invention provides a schematic diagram of field curvature and distortion.

[0017] Figure 5 To create a light spot pattern for this invention;

[0018] Figure 6 To create an illuminance map for this invention. Detailed Implementation

[0019] The invention will be further described below with reference to the accompanying drawings and specific embodiments, and its structure and advantages will become clearer:

[0020] See Figure 1 , 2 An ultra-low distortion, high-resolution industrial lens includes a lens barrel body 1. Within the lens barrel body 1, from the object side to the image side, are arranged a negative optical power front lens group, a negative optical power central focusing group, and a positive optical power rear lens group. The negative optical power front lens group consists of a positive optical power first lens G1, a negative optical power second lens G2, a negative optical power third lens G3, and a negative optical power fourth lens G4. The negative optical power central focusing group consists of a negative optical power fifth lens G5, and focusing is achieved by moving the relative position of the negative optical power fifth lens G5. The positive optical power rear lens group consists of a positive optical power sixth lens G6, a positive optical power seventh lens G7, a negative optical power eighth lens G8, a positive optical power ninth lens G9, and a negative optical power tenth lens G10, forming a cemented triplet lens, an eleventh positive optical power lens G11, and a twelfth positive optical power lens G12.

[0021] The positive power first lens G1 is a meniscus lens, which is fixed inside the lens barrel body 1 by an inner pressure ring. The first lens G1 uses positive power, which can effectively correct distortion and avoid fogging on the lens surface at high and low temperatures. The negative power second lens G2 is a meniscus lens, and a first spacer 6 is installed between the positive power first lens G1 and the negative power second lens G2.

[0022] Both the negative optical power third lens G3 and the negative optical power fourth lens G4 are meniscus lenses. The negative optical power second lens G2 and the negative optical power third lens G3 are directly connected, and the negative optical power third lens G3 and the negative optical power fourth lens G4 are directly connected.

[0023] The negative optical power fifth lens G5 is a meniscus lens. The negative optical power fifth lens G5 is fixed in the lens barrel body 1 through the sleeve 2 and the inner pressure ring, and is connected to the external focusing ring 4 through the focusing screw 3 to realize manual focusing. The focusing ring 4 can increase the focusing rotation angle, and the focusing process can be finely adjusted, making it easier to achieve clear focus.

[0024] The sixth positive power lens G6 is a biconvex lens, and it is fixed inside the lens barrel body 1 by an inner pressure ring. The seventh positive power lens G7 is also a biconvex lens, and it is fixed inside the lens barrel body 1 by an inner pressure ring. A manual aperture module 5 is provided between the sixth positive power lens G6 and the seventh positive power lens G7. The manual aperture module 5 is connected to the aperture ring by a guide pin, and the aperture is adjusted by fine-tuning the aperture ring. After adjusting to a certain position, locking it achieves aperture positioning.

[0025] The negative optical power eighth lens G8, the positive optical power ninth lens G9, and the negative optical power tenth lens G10 form a cemented three-layer lens, and a second spacer 7 is installed between the cemented three-layer lens and the positive optical power eleventh lens G11.

[0026] The eleventh positive power lens G11 and the twelfth positive power lens G12 are biconvex lenses. A third spacer 8 is installed between the eleventh positive power lens G11 and the twelfth positive power lens G12. The twelfth positive power lens G12 is fixed in the lens barrel body 1 by an external pressure ring.

[0027] The distance from the vertex of the rear surface of the positive power first lens G1 to the vertex of the front surface of the negative power second lens G2 in the negative power front lens group is 0.05-0.3mm;

[0028] The distance from the vertex of the rear surface of the negative power second lens G2 to the vertex of the front surface of the negative power third lens G3 in the negative power front lens group is 3.0-4.0 mm.

[0029] The distance from the vertex of the rear surface of the negative power third lens G3 to the vertex of the front surface of the negative power fourth lens G4 in the negative power front lens group is 2.3-3.5mm.

[0030] The distance from the vertex of the rear surface of the positive power fourth lens G4 of the negative power front lens group to the vertex of the front surface of the negative power fifth lens G5 of the negative power middle focusing group is 3-3.8mm.

[0031] The distance from the vertex of the rear surface of the fifth lens G5 of the negative optical power central focusing group to the vertex of the front surface of the sixth lens G6 of the positive optical power rear lens group is 3.0-4.0 mm.

[0032] The distance between the vertex of the rear surface of the sixth lens G6 of the positive optical power rear lens group and the vertex of the front surface of the manual aperture module 5 is 4.5mm-5.0mm;

[0033] The distance between the vertex of the rear surface of the manual aperture module 5 and the vertex of the front surface of the seventh lens G7 of the positive optical power rear lens group is 0.5mm-1.2mm.

[0034] The distance between the vertex of the rear surface of the positive power seventh lens G7 and the vertex of the front surface of the negative power eighth lens G8 in the positive power rear lens group is 1.1mm-2.0mm.

[0035] The distance between the vertex of the rear surface of the negative power tenth lens G10 and the vertex of the front surface of the positive power eleventh lens G11 in the positive power rear lens group is 0.5mm-1.5mm.

[0036] The distance between the vertex of the rear surface of the eleventh lens G11 and the vertex of the front surface of the twelfth lens G12 in the positive optical power rear lens group is 2.0mm-2.8mm.

[0037] The lens parameters of the ultra-low distortion, high-resolution industrial lens are as follows:

[0038]

[0039] See Figure 3-6 This invention discloses an ultra-low distortion, high-resolution industrial lens with manual aperture and focus adjustment. It achieves close-up effects from infinity to 0.1 meters, with an effective focal length f = 8mm, a maximum relative aperture number F / # = 1.5, a total optical system length of less than 70mm, an image size of 2 / 3 inch, a resolution of 5 megapixels, and a full field-of-view resolution of 140 lp / mm. It exhibits good image uniformity, with a peripheral to center illumination ratio exceeding 70%, and ultra-low distortion, with a total distortion rate of less than 1%. Compared to existing technologies, this ultra-low distortion, high-resolution industrial lens solution employs a miniaturized and compact structural design, making it easier to install in machine vision equipment. By combining lenses of different optical powers, using ultra-low distortion design technology, and a wide 400-1000nm spectrum, it thoroughly corrects distortion that causes difficulties in image processing, maximizing the suppression of image distortion, effectively reducing lens reflection loss, reducing glare, increasing contrast, and improving color reproduction, thereby more realistically reflecting image effects and improving image clarity.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] The embodiments described above are merely some examples of the present invention, and the concept and scope of the present invention are not limited to the details of the above exemplary embodiments. Therefore, various modifications and improvements made by other skilled personnel in the art based on the technical solutions of the present invention without departing from the inventive concept should fall within the protection scope of the present invention, and all the contents of the claims for protection of the present invention are set forth in the claims.

Claims

1. An ultra-low distortion, high-resolution industrial lens, characterized by: The lens includes a lens barrel body, within which, from the object side to the image side, are arranged a negative optical power front lens group, a negative optical power central focusing group, and a positive optical power rear lens group. The negative optical power front lens group consists of a positive optical power first lens, a negative optical power second lens, a negative optical power third lens, and a negative optical power fourth lens; the negative optical power central focusing group consists of a negative optical power fifth lens; and the positive optical power rear lens group consists of a positive optical power sixth lens, a positive optical power seventh lens, a negative optical power eighth lens, a positive optical power ninth lens, and a negative optical power tenth lens forming a cemented triplet lens, an eleventh positive optical power lens, and a twelfth positive optical power lens.

2. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: The positive optical power first lens is a meniscus lens, and the positive optical power first lens is fixed in the lens barrel body by an inner pressure ring; the negative optical power second lens is a meniscus lens, and a first spacer is installed between the positive optical power first lens and the negative optical power second lens.

3. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: Both the negative optical power third lens and the negative optical power fourth lens are meniscus lenses. The negative optical power second lens and the negative optical power third lens are directly connected, and the negative optical power third lens and the negative optical power fourth lens are directly connected.

4. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: The negative optical power fifth lens is a meniscus lens. The negative optical power fifth lens is fixed to the lens barrel body by a sleeve and an inner pressure ring, and is connected to the external focusing ring by a focusing screw.

5. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: The sixth lens with positive optical power is a biconvex lens, and the sixth lens with positive optical power is fixed in the lens barrel body by an inner pressure ring; the seventh lens with positive optical power is a biconvex lens, and the seventh lens with positive optical power is fixed in the lens barrel body by an inner pressure ring; a manual aperture module is provided between the sixth lens with positive optical power and the seventh lens with positive optical power.

6. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: The negative power eighth lens, together with the positive power ninth lens and the negative power tenth lens, form a cemented triplet lens, and a second spacer is installed between the cemented triplet lens and the positive power eleventh lens.

7. The ultra-low distortion high-resolution industrial lens as described in claim 1, characterized in that: The eleventh and twelfth positive power lenses are biconvex lenses. A third spacer is installed between the eleventh and twelfth positive power lenses. The twelfth positive power lens is fixed in the lens barrel body by an external pressure ring.

Images