TWM565800U - Small-size low-cost 4MP athermalized prime lens - Google Patents

Abstract

The novel belongs to the technical field of optical devices, and particularly relates to a small and low cost 4MP non-heating fixed focus lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order from the object side to the image side, wherein the first lens is a double concave negative power a plastic aspherical lens, the second lens is a concave-convex positive power plastic aspherical lens, the third lens is a double convex positive power glass spherical lens, and the fourth lens is a double concave negative power plastic aspherical surface a lens, the fifth lens being a biconvex positive power plastic aspheric lens. Compared with the prior art, the novel adopts a glass-glass optical structure with one glass spherical lens and four plastic aspherical lenses, which fully utilizes the advantages of easy processing of the glass lens and low cost of the plastic lens, and is matched with 4MP and 1/2.7 inch. The wafer can achieve 4MP resolution under both visible light and infrared light, which reduces cost and ensures performance.

Description

Small, low-cost 4MP non-heating fixed-focus lens

The novel creation is related to an optical device technology field, and in particular to a small low-cost 4MP non-heating fixed-focus lens.

With the development of data transmission and storage technology, in the field of surveillance, surveillance cameras with high-definition or full-HD pixels have gradually occupied the market. HD camera chips have 1280*720 pixels or 720p, and full-HD camera chips have 1920*1080 pixels. 1080p, there are still some 4MP pixel requirements; at the same time, the size of the wafer is different, the mainstream size is 1/3 inch or 1 / 2.7 inch. The specification of the chip determines the design requirements of the lens. The 4MP and 1/2.7-inch wafers are sufficient for better image quality. However, such lenses still have poor image quality, and the resolution needs to be improved to improve the resolution. This includes increasing the number of lenses, or using fewer lenses to reduce the aperture, but it will cause an increase in cost or an insufficient amount of light, so there is a problem that performance and cost are difficult to balance.

In view of this, it is indeed necessary to provide a small low-cost 4MP non-heating fixed-focus lens, which uses 1G+4P (one glass lens + 4 plastic lenses) glass-plastic optical structure, with 4MP, 1/2.7 inch The wafer can achieve 4MP resolution under both visible light and infrared light, which reduces cost and ensures performance.

The purpose of the novel is to provide a small and low-cost 4MP non-heating fixed-focus lens according to the deficiencies of the prior art, which adopts a glass structure of 1G+4P (one piece of glass lens + 4 pieces of plastic lens) combined with 4MP. The 1/2.7-inch wafer enables 4MP resolution in both visible and infrared light, reducing both cost and performance.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A small low-cost 4MP non-heating fixed-focus lens comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order from the object side to the image side, the first lens being double concave a power plastic aspherical lens, the second lens is a concave-convex positive power plastic aspherical lens, the third lens is a biconvex positive power glass spherical lens, and the fourth lens is a double concave negative power a plastic aspherical lens, wherein the fifth lens is a biconvex positive power plastic aspherical lens; a ratio of a focal length of the third lens and the fifth lens to a focal length of the entire lens satisfies the following condition: 1.94<|f3/ f|<2.35; 0.97<|f5/f|<1.53; wherein f is the focal length of the entire lens; f3 is the focal length of the third lens; and f5 is the focal length of the fifth lens.

As an improvement of the novel small-sized low-cost 4MP non-heating fixed-focus lens, the focal length, refractive index and radius of curvature of the first lens to the fifth lens satisfy the following conditions:

In the above table, "f" is the focal length, "n" is the refractive index, "R" is the radius of curvature, and "-" sign indicates the direction is negative; wherein f1 to f5 correspond to the first lens to the first a focal length of the five lenses; n1 to n5 respectively corresponding to refractive indices of the first lens to the fifth lens; R1, R3, R5, R7 and R9 respectively corresponding to the first lens to the fifth lens The radius of curvature of the side close to the object side, R2, R4, R6, R8, and R10 respectively correspond to the radius of curvature of the side of the first lens to the fifth lens that is away from the object side.

As an improvement of the novel small-sized low-cost 4MP non-heating fixed-focus lens, the first lens, the second lens, the fourth lens, and the fifth lens satisfy the following formula:

Wherein: z is a position at a height y of the aspherical lens along the optical axis direction, and a distance vector from the apex of the aspherical lens is high, c=1/R, and R represents a curvature of the center of the aspherical lens surface Radius, k represents the conic coefficient, and parameters A , B , C , D , E , and F are high-order aspheric coefficients.

As an improvement of the novel small-sized low-cost 4MP non-heating fixed-focus lens, the first lens and the second lens are closely matched by a soma, and the soma is a light shielding sheet.

As an improvement of the novel low-cost 4MP non-heating fixed-focus lens, the second lens and the third lens are closely fitted by a spacer.

As an improvement of the novel low-cost 4MP non-heating fixed-focus lens, the third lens and the fourth lens are closely fitted by a spacer.

As an improvement of the novel small-sized low-cost 4MP non-heating fixed-focus lens, the fourth lens and the fifth lens are closely matched by the soma.

Compared with the prior art, the present invention has the following advantages:

First, the first lens, the second lens, the fourth lens and the fifth lens of the present invention adopt plastic lenses, which achieve low cost and high performance, and the cost of the plastic lens is much lower than that of the glass spherical lens, thereby reducing the cost; Moreover, since the first lens, the second lens, the fourth lens and the fifth lens of the present invention all adopt aspherical lenses, the performance is improved compared with the conventional spherical lenses.

Secondly, the novel adopts a glass-glass optical structure with one glass spherical lens and four plastic aspherical lenses, which fully utilizes the advantages of easy processing of glass lenses and low cost of plastic lenses, and is matched with 4MP and 1/2.7 inch wafers. It can achieve 4MP resolution under both visible light and infrared light, which reduces cost and guarantees performance.

Third, the visible light of the novel can reach a million pixels, and the imaging quality is good through the reasonable use of the combination of glass and optical plastic, and the infrared light can be clearly imaged without the focus adjustment in the case of clear visible light imaging, and Infrared imaging can also reach megapixels, enabling clear and bright monitoring even at night with low illumination The picture realizes day and night confocal function. At the same time, it has temperature compensation function and passive non-heating function, which can achieve the use of -30~+80 °C without defocusing.

1‧‧‧first lens

2‧‧‧second lens

3‧‧‧ third lens

4‧‧‧ fourth lens

5‧‧‧ fifth lens

Figure 1 is a schematic view of the optical structure of the present invention.

Figure 2 is a schematic view of the assembled structure of the present invention.

The present invention and its beneficial effects will be further described in detail below with reference to specific embodiments, but the specific embodiments of the present invention are not limited thereto.

As shown in FIG. 1 and FIG. 2, the present invention provides a small low-cost 4MP non-heating fixed-focus lens, which includes a first lens 1, a second lens 2, and a third lens 3 which are arranged in order from the object side to the image side. The fourth lens 4 and the fifth lens 5, the first lens 1 is a double concave negative power plastic aspheric lens, the second lens 2 is a concave-convex positive power plastic aspheric lens, and the third lens 3 is a double convex positive power a glass spherical lens, the fourth lens 4 is a double concave negative power plastic aspheric lens, and the fifth lens 5 is a double convex positive power plastic aspheric lens;

The ratio of the focal length of the third lens 3 and the fifth lens 5 to the focal length of the entire lens satisfies the following condition: 1.94 <|f3/f|<2.35; 0.97<|f5/f|<1.53; Where f is the focal length of the entire lens; f3 is the focal length of the third lens 3; f5 is the focal length of the fifth lens 5 for the purpose of miniaturization and high performance.

The focal length, refractive index, and radius of curvature of the first lens 1 to the fifth lens 5 satisfy the following conditions:

In the above table, "f" is the focal length, "n" is the refractive index, "R" is the radius of curvature, and "-" sign indicates the direction is negative; wherein f1 to f5 correspond to the first lens 1 to the fifth lens 5, respectively. The focal lengths; n1 to n5 correspond to the refractive indices of the first lens 1 to the fifth lens 5, respectively; R1, R3, R5, R7, and R9 correspond to the object-side side of the first lens 1 to the fifth lens 5, respectively. The radius of curvature, R2, R4, R6, R8, and R10 respectively correspond to the radii of curvature of the side of the first lens 1 to the fifth lens 5 that are away from the object side.

The first lens 1, the second lens 2, the fourth lens 4, and the fifth lens 5 satisfy the following formula:

Where: z is the position of the aspherical lens at a height y along the optical axis, the distance from the apex of the aspheric lens is high, c=1/R, R represents the radius of curvature of the center of the aspheric lens, and k represents the conic coefficient The parameters A , B , C , D , E , and F are high-order aspheric coefficients.

The first lens 1 and the second lens 2 are closely matched by a soma.

The second lens 2 and the third lens 3 are fitted by a spacer.

The third lens 3 and the fourth lens 4 are closely fitted by a spacer.

The fourth lens 4 and the fifth lens 5 are closely matched by the soma.

Example 1

As shown in FIGS. 1 and 2, the present embodiment provides a small low-cost 4MP non-heating fixed-focus lens, including a first lens 1, a second lens 2, and a third lens 3 arranged in order from the object side to the image side. The fourth lens 4 and the fifth lens 5, the first lens 1 is a double concave negative power plastic aspheric lens, the second lens 2 is a concave-convex positive power plastic aspheric lens, and the third lens 3 is a double convex positive power The glass spherical lens, the fourth lens 4 is a double concave negative power plastic aspheric lens, and the fifth lens 5 is a double convex positive power plastic aspheric lens; the first lens 1 and the second lens 2 are closely matched by the soma. The second lens 2 and the third lens 3 are fitted by a spacer. The third lens 3 and the fourth lens 4 are closely fitted by a spacer. The fourth lens 4 and the fifth lens 5 are closely matched by the soma.

In this embodiment, the face shape, the curvature radius R, the lens thickness, the lens pitch, and the lens refractive index nd and K values of the respective lenses satisfy the following conditions (Table 1):

In Table 1, "R" is the radius of curvature, "-" sign indicates that the direction is negative, and "PL" indicates the plane. The same face number on the upper table has both the refractive index data nd and the data D. The data D indicates the thickness at the axial center of the lens, and the data D having the same surface number only the data D and no refractive index data nd indicates the pitch of the lens to the next lens surface. The surface numbers 1 and 2 correspond to the object-facing surface of the first lens 1 and the image-facing surface, respectively; the surface numbers 3 and 4 correspond to the object-facing surface of the second lens 2 and the image-facing surface, respectively; 5 and 6 respectively correspond to the object-facing surface of the third lens 3 and the image-facing surface; the surface numbers 7 and 8 correspond to the object-oriented surface of the fourth lens 4 and the image-facing surface, respectively; 10 corresponds to the object-facing surface of the fifth lens 5 and the surface-facing surface, respectively.

The faces of the surface numbers 1, 2, 3, 4, 7, 8, 9 and 10 in Table 1 are aspherical, and the aspherical lens satisfies the following formula:

Where: z is the position of the aspherical lens at a height y along the optical axis, the distance from the apex of the aspheric lens is high, c=1/R, R represents the radius of curvature of the center of the aspheric lens, and k represents the conic coefficient The parameters A , B , C , D , E , and F are high-order aspheric coefficients.

The aspherical surface parameters in this embodiment are shown in Table 2:

In summary, the present invention has the following advantages:

First, the first lens 1, the second lens 2, the fourth lens 4, and the fifth lens 5 of the present invention adopt plastic lenses, which achieve low cost and high performance, and the cost of the plastic lens is much lower than that of the glass spherical lens. The cost is reduced; and since the first lens 1, the second lens 2, the fourth lens 4, and the fifth lens 5 of the present invention each employ an aspherical lens, the performance is improved compared to the conventional spherical lens.

Secondly, the novel adopts a glass-glass optical structure with one glass spherical lens and four plastic aspherical lenses, which fully utilizes the advantages of easy processing of glass lenses and low cost of plastic lenses, and is matched with 4MP and 1/2.7 inch wafers. It can achieve 4MP resolution under both visible light and infrared light, which reduces cost and guarantees performance.

Third, the novel visible light can reach megapixels, and the image quality is good through the reasonable use of glass and optical plastic combination, and the visible image is visible. In the case, the infrared light can be clearly imaged without focusing, and the infrared imaging can reach megapixels, and the clear and bright monitoring picture can be realized even under low illumination at night, and the day and night confocal function can be realized. At the same time, it has temperature compensation function and passive non-heating function, which can achieve the use of -30~+80 °C without defocusing.

Those skilled in the art can also make appropriate changes and modifications to the above-described embodiments in light of the above disclosure and teachings. Therefore, the present invention is not limited to the specific embodiments disclosed and described herein, and modifications and variations of the present invention are intended to fall within the scope of the appended claims. In addition, although some specific terms are used in the specification, these terms are merely for convenience of description and do not constitute any limitation to the present invention.

Claims (5)

A small low-cost 4MP non-heating fixed-focus lens comprising: a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order from the object side to the image side, the first lens being double a concave negative power plastic aspherical lens, the second lens is a concave-convex positive power plastic aspherical lens, the third lens is a biconvex positive power glass spherical lens, and the fourth lens is a double concave negative light a focal plastic aspherical lens, wherein the fifth lens is a biconvex positive power plastic aspherical lens; a ratio of a focal length of the third lens and the fifth lens to a focal length of the entire lens satisfies the following condition: 1.94<| F3/f|<2.35; 0.97<|f5/f|<1.53; wherein f is the focal length of the entire lens; f3 is the focal length of the third lens; and f5 is the focal length of the fifth lens. The small low-cost 4MP non-heating fixed-focus lens according to claim 1, wherein a focal length, a refractive index, and a radius of curvature of the first lens to the fifth lens satisfy the following conditions: In the above table, "f" is the focal length, "n" is the refractive index, "R" is the radius of curvature, and "-" sign indicates that the direction is negative; wherein f1 to f5 correspond to the first lens to the first a focal length of the five lenses; n1 to n5 respectively corresponding to refractive indices of the first lens to the fifth lens; R1, R3, R5, R7 and R9 respectively corresponding to the first lens to the fifth lens The radius of curvature of the side close to the object side, R2, R4, R6, R8, and R10 respectively correspond to the radius of curvature of the side of the first lens to the fifth lens that is away from the object side. The small-sized, low-cost 4MP non-heating fixed-focus lens of claim 1, wherein the first lens, the second lens, the fourth lens, and the fifth lens satisfy the following formula: Wherein: z is a position at a height y of the aspherical lens along the optical axis direction, and a distance vector from the apex of the aspherical lens is high, c=1/R, and R represents a curvature of the center of the aspherical lens surface Radius, k represents the conic coefficient, and parameters A , B , C , D , E , and F are high-order aspheric coefficients. The small low-cost 4MP non-heating fixed-focus lens according to claim 1, wherein the second lens and the third lens are closely fitted by a spacer. The small low-cost 4MP non-heating fixed-focus lens according to claim 1, wherein the third lens and the fourth lens are closely fitted by a spacer.