KR102365339B1 - Lens device for photography with multilayer uv resin lens structure - Google Patents

Abstract

+

+

+

+

+

+ …

, z는 x축에 수직한 면의 세그먼트(segment), K는 코닉상수(conic constant), C는 곡률(curvature),

는 비구면 계수(aspheric coefficients)로 정의되는 비구면식을 따른 형상을 가진다.An embodiment of the present invention provides a lens device for photographing having a multilayer UV resin lens structure including a plurality of lenses. Each lens of the plurality of lenses of the lens device for photographing having a multilayer UV resin lens structure is made of UV (UltraViolet) resin, and the plurality of lenses are interconnected in a form in which four or more lenses are arranged in a line based on the optical axis. to form bonding surfaces, but the bonding surface is formed so that an air layer is not interposed between the lenses in contact with each other, the bonding surface has an aspherical shape, and the aspherical surface is, z =

+

+

+

+

+

+ …

, z is the segment of the plane perpendicular to the x-axis, K is the conic constant, C is the curvature,

has a shape according to an aspheric equation defined by aspheric coefficients.

Description

Lens device for photography having a multilayer UV resin lens structure {LENS DEVICE FOR PHOTOGRAPHY WITH MULTILAYER UV RESIN LENS STRUCTURE}

The present invention relates to a lens device for photographing having a multilayer UV resin lens structure, and more particularly, to a lens device for photographing having a multilayer UV resin lens structure in which chromatic aberration is suppressed and problems caused by thermal expansion are suppressed.

The lens optical system for photography is applied to automobile technology and helps drivers in various ways. It not only plays a role in resolving accidents by recording all images through the black box, which is the eye of a car, but also enables safe driving by securing the view behind the vehicle through the rear camera.

As the role of vehicle cameras increases day by day, consumers' desire for clear images is also increasing.

In recent years, in the optical lens optical system market for photographing used to determine license plates of people, objects, and vehicles, the number of consumers requesting high-resolution images is gradually increasing.

On the other hand, in the conventional optical system for photographing, an air layer is formed between the lens and the lens by spacing lenses made of a glass material or a thermoplastic material at regular intervals through a spacer.

For example, as shown in FIG. 1, a conventional camera lens uses a glass material or a thermoplastic material as described above and assembles lenses made of a thermoplastic material into a single barrel, but at regular intervals through the use of spacers manufactured to maintain Accordingly, it is designed to have a structure that best meets the conditions made during the lens design process, for example, light focus.

However, in the conventional camera lens structure, when lenses are to be assembled to the barrel, a lens manufacturing process having high precision such as processing precision and assembly precision of the barrel and the spacer is required. Due to the high precision of the lens manufacturing process, even if a good product is produced for a single lens unit, there is a problem in that the yield of the assembled product is significantly lowered due to the limitations of the barrel and spacer processing technology and the limitation of the possible assembly precision.

In addition, when the lenses are assembled to the barrel, the lens material and the air layer are alternately positioned, and only the spherical surface is required when a surface formed by contacting the lens material, not the air, is required. However, in the case of an aspherical surface other than a spherical surface, since it is difficult to perfectly match the shape of the joint surface of the lens, there is no application of the joint surface having an aspherical surface made of lens materials other than air.

On the other hand, when light passes through media with different refractive indices, reflection occurs at the interface, which is called Fresnel reflection. The reflection generated at this time causes unwanted light loss. The Fresnel reflection equation is as follows.

(F(0°)는 Fresnel at Degree 0°로, 물체를 수직에서 바라본 반사율을 넣는 근사 계산식을 사용한다.F(0°) =

(F(0°) is Fresnel at Degree 0°, and an approximate calculation formula is used to insert the reflectance of the object viewed from the vertical.

In the conventional lens system for photographing, a method of alternately positioning lenses and air layers by placing a spacer in one barrel of lenses made of mainly glass and thermoplastic materials is preferred.

Applying the above lens system to the Fresnel reflection formula, looking at the degree of light loss,

(0°) =

= 0.04 = 4% (유리소재의 굴절률

= 1.5, 공기의 굴절률

= 1.0)

(0°) =

= 0.04 = 4% (refractive index of glass material)

= 1.5, the refractive index of air

= 1.0)

This means that the light loss generated at one interface is 4%, which means that approximately 8% of the light loss occurs in one lens.

In order to prevent light loss, the development of a lens material in which the lens material is in contact has been made, but in order to perfectly match the shape when the bonding surface is an aspherical surface, it is inefficient due to the difficulty of the process and the cost and time required for processing.

In addition, in the optical system for photographing of the conventional camera lens structure, the difference in refractive index between the lens material and the air layer is large, and since the path of light is sharply bent, chromatic aberration is severe.

The occurrence of chromatic aberration in the lens optical system for photographing causes several problems. This is because the optical performance of the lens deteriorates as the focus position and magnification are changed, reducing sharpness, resolution, and contrast.

Furthermore, when assembled using injection lenses or lenses made of glass material, thermal expansion of the lens material according to temperature change proceeds to a considerable extent, and the shape changes, which causes a change in sensitive optical characteristics.

The technical problem to be achieved by the present invention is to reduce the occurrence of chromatic aberration by having a plurality of lenses made of UV resins of similar refractive index without an air layer, and reduce the difference in thermal expansion coefficient between lenses according to temperature change, thereby providing stable image quality and improved MTF (Modulation Transfer) function) is achieved.

Another object of the present invention is to provide a lens device for photographing having a multi-layered UV resin lens structure capable of reducing distortion and resolving astigmatism and spherical aberration occurring in a spherical lens because the junction surface between the lenses has an aspherical shape.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. There will be.

In order to achieve the above technical object, an embodiment of the present invention provides a lens device for photographing having a multilayer UV resin lens structure including a plurality of lenses. Each lens of the plurality of lenses of the lens device for photographing having a multilayer UV resin lens structure is made of UV (UltraViolet) resin, and the plurality of lenses are interconnected in a form in which four or more lenses are arranged in a line based on the optical axis to form bonding surfaces, the bonding surface is formed so that an air layer is not interposed between the lenses in contact with each other, the bonding surface having an aspherical shape, the aspherical surface,

+

+

+

+

+

+ …

z =

+

+

+

+

+

+ …

는 비구면 계수(aspheric coefficients)로 정의되는 비구면식을 따른 형상을 가진다.z is the segment of the plane perpendicular to the x-axis, K is the conic constant, C is the curvature,

has a shape according to an aspheric equation defined by aspheric coefficients.

In an embodiment of the present invention, in the plurality of lenses, a lens having a relatively high refractive index and a lens having a relatively low refractive index may be alternately arranged from the input side to the output side along the optical axis.

In an embodiment of the present invention, among the plurality of lenses, the lenses having each of the low refractive indexes may have the same or different refractive indices, and the lenses having the respective high refractive indexes may have the same or different refractive indices.

은 1.42

1.72 범위 내일 수 있다.In an embodiment of the present invention, in order to reduce the occurrence of chromatic aberration and reduce the difference in thermal expansion, the refractive index (

Silver 1.42

It can be within the 1.72 range.

0.94, 또는

1.22 의 범위 내일 수 있다.In an embodiment of the present invention, in order to reduce the occurrence of chromatic aberration and reduce the difference in thermal expansion, the relative refractive index (

0.94, or

It can be within the range of 1.22.

In an embodiment of the present invention, the plurality of lenses form eight bonding surfaces, including nine lenses arranged from the input side to the output side along the optical axis, and the eight bonding surfaces are directed toward the input side. When the protruding shape is defined as convex, it may have a convex surface, a concave surface, a concave surface, a convex surface, a concave surface, a convex surface, a concave surface, and a convex surface shape in order from the input side to the output side. .

In an embodiment of the present invention, the plurality of lenses form 10 bonding surfaces including 11 lenses arranged from the input side to the output side along the optical axis, and the ten bonding surfaces are directed toward the input side. When the protruding shape is defined as convex, in order from the input side to the output side, convex surface, concave surface, concave surface, convex surface, concave surface, convex surface, concave surface, convex surface, concave surface, convex surface It may have a surface or a convex surface shape.

In an embodiment of the present invention, in the order from the input side to the output side, the first to seventh lenses have a dispersion coefficient (Vd) of 40 or less, a lens having a relatively high dispersion coefficient, and a relatively low dispersion coefficient The lenses may be alternately arranged, the eighth lens may have a dispersion coefficient greater than 40 and less than 50, and the ninth lens may have a dispersion coefficient of 40 or less.

In an embodiment of the present invention, the dispersion coefficient of the lens having the relatively high dispersion coefficient may be 25 or more and 26 or less, and the dispersion coefficient of the lens having the relatively low dispersion coefficient may be 13 or more and 14 or less.

In an embodiment of the present invention, an anti-reflection film may be formed on the outer surfaces of the two lenses positioned at the outermost sides with respect to the optical axis.

According to an embodiment of the present invention, it is possible to reduce light loss at the lens junction (interface) through a lens device for photographing having a multilayer UV resin lens structure in which an air layer is not formed, and by using UV resins of similar refractive index By manufacturing and bonding each lens, it is possible to provide a lens device for photographing having a stable multilayer UV resin lens structure, since the occurrence of chromatic aberration is suppressed and the refractive index change according to temperature changes to a similar level.

According to an embodiment of the present invention, stable image quality and improved MTF (Modulation Transfer Function) are obtained by reducing the occurrence of chromatic aberration and minimizing the shape change of the lens material according to the temperature change through the lens system of the multilayer structure manufactured using UV resin. can have an effect.

According to the embodiment of the present invention, unlike the conventional lens optical system for photographing, which requires AR Coating to be applied on all surfaces, the optical lens system for photographing applies an antireflection coating treatment to only the first and end surfaces that come into contact with the air layer. By doing so, you can reduce costs.

According to an embodiment of the present invention, a lens having a multi-layer structure manufactured using UV resin has an aspherical shape, and an aspherical lens has an advantage in that it is easy to correct aberrations (spherical, astigmatism) and distortion.

Furthermore, according to an embodiment of the present invention, since the method for manufacturing a lens having a multilayer structure leads to simplification of the process, there is an effect that can overcome the difficulty of the process, a lot of cost and time required for processing, which are considered as disadvantages of the bonding lens.

The lens device for photographing having such a multilayer UV resin lens structure can be easily applied to a black box of a vehicle, a rear camera of a vehicle, and the like, and can provide a high-resolution photographing lens suitable for this.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a diagram schematically illustrating a structure of a conventional camera lens.
2 is a view showing a lens device for photographing having a multilayer UV resin lens structure according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of a Modulation Transfer Function (MTF) graph of a lens device for photographing having a multilayer UV resin lens structure shown in FIG. 2 .
4 is a view showing an example of an astigmatism curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 2 .
FIG. 5 is a view showing an example of a distortion curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 2 .
6 is a view showing a lens device for photographing having a multilayer UV resin lens structure according to another embodiment of the present invention.
FIG. 7 is a diagram illustrating an example of a modulation transfer function (MTF) graph of a lens device for photographing having a multilayer UV resin lens structure shown in FIG. 6 .
8 is a view showing an example of an astigmatism curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 6 .
9 is a view showing an example of a distortion curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 6 .

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be “connected (connected, contacted, coupled)” with another part, it is not only “directly connected” but also “indirectly connected” with another member interposed therebetween. "Including cases where In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing a lens device for photographing having a multilayer UV resin lens structure according to an embodiment of the present invention.

A lens device for photographing having a multilayer UV resin lens structure includes a plurality of lenses.

Each lens of the plurality of lenses is made of UV (UltraViolet) resin. The plurality of lenses may be mutually bonded in a form in which four or more lenses are arranged in a line based on the optical axis to form bonding surfaces 2, 3, 4, 5, 6, 7, 8, 9. Here, the junction plane refers to an interface between two adjacent lenses. In this embodiment, the bonding surface is formed so that an air layer is not interposed between the lenses in contact with each other.

The joint surface has a rotationally symmetric aspherical shape, but the aspherical surface may have a shape conforming to the following aspherical formula.

+

+

+

+

+

+ …

z =

+

+

+

+

+

+ …

는 비구면 계수(aspheric coefficients)이다.z is the segment of the plane perpendicular to the x-axis, K is the conic constant, C is the curvature,

are the aspheric coefficients.

Here, the z denotes a direction parallel to the optical axis, and the x-axis denotes an axis perpendicular to the optical axis. The optical axis refers to a direction in which light travels, and refers to a direction from an input side to an output side. In optical design, design can proceed with the z-axis as the optical axis.

An example in which nine lenses are arranged in this embodiment is shown in FIG. 2 .

The plurality of lenses may form eight bonding surfaces, including nine lenses arranged from the input side to the output side along the optical axis. The eight bonding surfaces may have a convex surface, a concave surface, a concave surface, a convex surface, a concave surface, a convex surface, a concave surface, and a convex surface shape in order from the input side to the output side.

The number of lenses and the shape of each bonding surface may be changed according to an applied lens system, and are not limited to the example shown in FIG. 2 .

In the plurality of lenses of this embodiment, lenses having a relatively high refractive index and lenses having a relatively low refractive index may be alternately arranged from the input side to the output side along the optical axis.

Among the plurality of lenses, lenses having each low refractive index may have the same or different refractive indices, and lenses having each high refractive index may have the same or different refractive indices.

If the difference in refractive index at the junction surface is large, the path of light is sharply bent, so chromatic aberration may occur severely. In addition, if the difference in refractive index is large, that is, if the difference in the characteristics of the materials is large, the difference in the thermal expansion coefficient is also large, and in this case, the sensitive optical characteristic varies according to the temperature due to the difference in the thermal expansion coefficient, which is a problem.

Accordingly, each lens of the lens device for photographing having the multilayer UV resin lens structure of the present embodiment may be manufactured by using a UV resin having a small refractive index difference to suppress the occurrence of chromatic aberration and to have a small difference in the thermal expansion coefficient of each lens.

은 1.42

1.72 범위 내에 있는 것이 사용될 수 있다.For example, the refractive index of the UV resin for manufacturing each lens of a plurality of lenses (

Silver 1.42

Anything within the 1.72 range may be used.

In the present embodiment, the relative refractive index at the interface between the lens and the lens, that is, at the bonding surface, may be determined only by the refractive indices of the two lenses because the air layer is not interposed.

에 대한 범위를 적합하게 한정 지을 수 있다.Relative relative refractive index at the bonding surface of each lens made of UV resin having a refractive index within the above range

The range for can be appropriately limited.

For example, assuming that the lens is manufactured using the lowest refractive index UV resin and the highest refractive index UV resin,

=

=

(

, 또는relative refractive index

=

=

(

, or

=

(

일 수 있다.

=

(

can be

In this embodiment, in order to reduce the occurrence of chromatic aberration and reduce the difference in thermal expansion, the relative refractive index (

0.94, 또는

1.22의 범위 내로 제조되는 것이 바람직하다.

0.94, or

It is preferably prepared within the range of 1.22.

An anti-reflection film may be formed on the outer surfaces of the two lenses positioned at the outermost sides with respect to the optical axis.

An example of detailed specifications of a lens device for photographing having a multilayer UV resin lens structure manufactured to have a refractive index and a relative refractive index within the above ranges is illustrated in Table 1.

Angle of view (°) sensor iris Focal length (mm) TTL
(mm) D 70 1/2.56″ 1.8 6.0 24.2

In the photographing lens device having a multilayer UV resin lens structure, in the order from the input side to the output side, the first to seventh lenses have a dispersion coefficient (Vd) of 40 or less, a lens having a relatively high dispersion coefficient, and a relatively low Lenses having a dispersion coefficient are alternately arranged, the eighth lens may have a dispersion coefficient greater than 40 and less than 50, and the ninth lens may have a dispersion coefficient of 40 or less.

As a more specific example, a dispersion coefficient of a lens having a relatively high dispersion coefficient may be 25 or more and 26 or less, and a dispersion coefficient of a lens having a relatively low dispersion coefficient may be 13 or more and 14 or less.

Next, in Table 2, a lens device for photographing having a specific multilayer UV resin lens structure realizing the above-described embodiment is exemplified.

Table 2 shows the radius and distance of each interface (junction surface) constituting the lens optical system of the lens device for photographing having a multilayer UV resin lens structure, and the refractive index and dispersion coefficient (Vd) of each lens.

Position Surface Type radius distance

refractive index

coefficient of variance

Infinity Infinity Surface #1 Asphere 203.9470 1.0000 1.723 25.78 Surface #2 Asphere 3.4823 4.1017 1.418 13.56 Surface #3 Asphere -1.6763 1.5459 1.723 25.78 Surface #4 Asphere -2.7905 1.0000 1.418 13.56 Surface #5 Asphere 4.3917 2.9855 1.723 25.78 Stop Asphere -3.9817 1.0000 1.418 13.56 Surface #7 Asphere 14.2777 2.8056 1.723 25.78 Surface #8 Asphere -5.6455 1.7517 1.581 46.05 Surface #9 Asphere 16.6436 1.7632 1.723 25.78 Surface #10 Asphere 72.4977 2.6573 IR Filter Infinity 0.2100 1.517 64.20 Infinity 3.3792 Image Infinity

Referring to [Table 2] and FIGS. 3 to 6, in the lens configuration of the lens device for photographing having the multilayer UV resin lens structure according to the embodiment of the present invention illustrated in Table 2, the material of the lens is the UV resin. The refractive index and dispersion coefficient may have the following characteristics.

As described above, the plurality of lenses arranged along the optical axis have a structure in which relatively high refractive index lenses and low refractive index lenses are alternately arranged from an input side on which light is incident to an output side on which an image is formed.

Each of the high refractive index lenses may have the same refractive index or different refractive index. Each of the low refractive index lenses may have the same refractive index or different refractive index.

In the examples presented in Table 2, it can be seen that lenses are formed by several types of resins.

의 굴절률

은 1.42 이고 분산계수

은 13.56 이다.First, in the case of a low refractive index lens, it is manufactured by Lesin1,

refractive index of

is 1.42 and the coefficient of variance is

is 13.56.

의 굴절률

은 1.72 이고 분산계수

은 25.78 이다.High refractive index lenses are manufactured by Lesin3,

refractive index of

is 1.72 and the coefficient of variance is

is 25.78.

의 굴절률

은 1.58 이고 분산계수

은 46.05 이다.Additional high refractive index lenses are manufactured by Lesin2,

refractive index of

is 1.58 and the coefficient of variance is

is 46.05.

The plurality of lenses of the lens device for photographing having a multilayer UV resin lens structure starts with a high refractive index lens made of Lesin3, and a low refractive index lens and a high refractive index lens are alternately arranged.

Further, the 8th lens is a lens made of Lesin2, the refractive index is between the 7th lens and the 9th lens, and the dispersion coefficient is larger than that of the 7th lens and the 9th lens.

That is, the refractive index relation

(

와 같이 표현될 수 있다.

(

can be expressed as

The variance coefficient relation is,

(

(

와 같이 표현될 수 있다.

can be expressed as

That is, in the lens device for photographing having the multilayer UV resin lens structure according to the embodiment of the present invention shown in Table 2 and FIGS. 3 to 6, the lenses made of the high refractive index UV resin and the lenses made of the low refractive index UV resin are alternately arranged. .

On the other hand, in the case of the dispersion coefficient, the lenses of the UV resin having a large dispersion coefficient are alternately arranged in the order of the lenses made of the UV resin having a small dispersion coefficient, and in the second half of the arrangement, for example, in this embodiment, The eighth lens is made of a UV resin having a higher dispersion coefficient than the seventh lens and the ninth lens, which are high dispersion coefficient lenses.

As shown in Table 2, the first surface of the first lens has a radius of 203.947 mm, the second surface has a radius of 3.483 mm, and the distance (thickness) of the first lens is 1.000 mm.

Here, in each lens, the first surface means a surface facing the input side, and the second surface means a surface facing the output side.

The first surface of the second lens is equal to the radius of the second surface of the first lens because it is a conjugate lens. The radius of the second surface is -1.6763 mm, and the distance (thickness) of the second lens is 4.1017 mm.

In this way, a total of 9 lenses are configured. The first surface of the ninth lens is 16.6436 mm, the second surface has 72.4977 mm, and the distance (thickness) of the ninth lens is 1.7632 mm.

The ratio of a certain distance (thickness) is

If the ratio of Surface #1: Surface #2 is x_1, 1: 3.75 ≤ x_1 ≤ 4.25.

Here, Surface #1 is a number marked on the surface of the lens shown in FIG. 2 .

If the ratio of Surface #4: Surface #5 is x_2 and the ratio of Surface #Stop: Surface #7 is x_3, 1: 2.75 ≤ x_2= x_3 ≤ 3.25.

If the ratio of Surface #8: Surface #9 is x_4, 1: 0.75 ≤ x_4 ≤ 1.25.

Although it has been exemplified that the range of the ratio has a range of ±0.25, the embodiment of the present invention is not limited thereto.

FIG. 3 is a diagram illustrating an example of a modulation transfer function (MTF) graph of a lens device for photographing having a multilayer UV resin lens structure shown in FIG. 2 . 4 is a view showing an example of an astigmatism curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 2 . FIG. 5 is a diagram illustrating an example of a distortion curve of a lens device for photographing having a multilayer UV resin lens structure shown in FIG. 2 .

Referring to FIG. 3 , the MTF curve shows resolution and contrast information at the same time, so it can be used to evaluate a lens based on the requirements for each application and to compare the performance of several lenses.

In the MTF curve, it can be seen that the closer to the Diff.Limit limit line (dotted line), the closer to the theoretical limit line of resolution. Referring to the MTF curve as shown in FIG. 3 for the lens device for photographing having the multilayer UV resin lens structure in this embodiment, it was confirmed that the MTF curve satisfies the specifications required by the lens optical system for photographing (eg, for vehicle).

As shown in FIG. 4 , the Astigmatic Curve curve means that the performance is better as it is closer to 0 mm (middle axis). As shown in Fig. 4, looking at the astigmatism curve, it can be confirmed that it almost coincides with the central axis.

In the distortion curve shown in FIG. 5, the closer to 0% (middle axis), the better the performance is evaluated. As in the case of the lens device for photographing having the multilayer UV resin lens structure in the present embodiment, it was confirmed that when the number of lenses increased, the center axis became closer.

In addition, in the case of the lens device for photographing having the multilayer UV resin lens structure according to the present embodiment, chromatic aberration is suppressed by bonding the lenses without an air layer as described above.

By bonding lenses of a low-dispersion material having little difference in refractive index, the occurrence of chromatic aberration can be suppressed.

UV resin is generally a highly dispersed material that disperses well compared to glass, but the lens device for photographing having a multilayer UV resin lens structure in this embodiment has a special configuration as described above, and it was confirmed that it has good resolution. .

6 is a view showing a lens device for photographing having a multilayer UV resin lens structure according to another embodiment of the present invention.

In the embodiment shown in FIG. 6 , in the lens device for photographing having a multilayer UV resin lens structure, the number of lenses is increased, and the multilayer UV described in FIGS. 2 to 5 except that the shape of each lens is changed as necessary It has characteristics similar to those of a lens device for photographing having a resin lens structure.

In this embodiment, the lens device for photographing having a multilayer UV resin lens structure includes a plurality of lenses.

The plurality of lenses may form 10 bonding surfaces, including 11 lenses arranged from the input side to the output side along the optical axis.

When defining the shape protruding toward the input side as being convex, the ten joint surfaces are, in order from the input side to the output side, a convex surface, a concave surface, a concave surface, a convex surface, a concave surface, a convex surface, and a concave surface. , has a convex surface, a concave surface, and a convex surface shape.

High refractive index lenses and low refractive index lenses are alternately arranged from the input side to the output side, and the arrangement pattern of the dispersion coefficients of these lenses is similar to the example shown in FIG. there is. In addition, in the second half of the arrangement, for example, in the ninth or tenth, a lens having a dispersion coefficient larger than a high dispersion coefficient and a low refractive index lens than the neighboring lenses may be arranged.

7 is a diagram illustrating an example of a modulation transfer function (MTF) graph of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 8 . FIG. 8 is a diagram illustrating an example of an astigmatism curve of a lens device for photographing having a multilayer UV resin lens structure shown in FIG. 6 . 9 is a view showing an example of a distortion curve of the lens device for photographing having the multilayer UV resin lens structure shown in FIG. 6 .

In the case of the present embodiment, since more controllable variables when optimization (design) is performed through an increase in the number of lenses, there is an advantage in that a means for overcoming a limitation in design is further provided. That is, it is possible to provide ease of improving the MTF curve and correcting distortion.

Specifically, when the number of lenses is increased as in this embodiment, the Diff. You can see that it is closer to the limit line (the black dotted line located at the top of the graph). Diff. It can be seen that the closer to the limit line, the better the resolution (resolution). Also, it can be seen that the distortion graph has a shape that is closer to 0%.

In the method of manufacturing a lens device for photographing having a multi-layered UV resin lens structure according to an embodiment of the present invention, a plurality of lenses may be formed and assembled at the same time by using the UV resin.

For example, in a method of manufacturing a lens device for photographing having a multilayer UV resin lens structure, first, a barrel is mounted on the lower lens core, then UV resin is applied, pressed using an upper mold, and cured to harden the first lens to form

Thereafter, a second lens is formed by applying a UV resin on the cured first lens shape, pressing it using a second upper mold, and then curing it.

Contrary to the conventional multi-layered lens in which it is difficult to perfectly match the shapes of the first lens and the second lens on the bonding surface, the manufacturing method of the present embodiment may facilitate shape matching on the bonding surface.

In particular, when the shape of the joint surface is aspherical, the effect can be maximized.

By repeating the above method, a plurality of lenses may be formed in the case of 9 lenses in FIG. 2 and 11 lenses in FIG. 7 .

By constructing a multi-layer structure lens in this way, unlike conventional lenses using glass or thermoplastic materials, a bonding lens made of UV resin can overcome the above disadvantages in processing and manufacturing.

When looking at the degree of light loss when manufacturing a multi-layered lens using UV resin,

(0°) =

=

0.009

0.9% (UV 레진1의 굴절률

= 1.72, UV 레진2의 굴절률

= 1.42)로서, 약 0.9%의 빛 손실이 발생하게 되는데, 이 수치는 공기층이 형성되어 있는 종래의 촬영용 렌즈 시스템에서의 손실되는 빛의 22.5% 수준이다.

(0°) =

=

0.009

0.9% (refractive index of UV resin 1)

= 1.72, refractive index of UV resin 2

= 1.42), a light loss of about 0.9% occurs, which is 22.5% of the light loss in a conventional lens system for photographing in which an air layer is formed.

Meanwhile, since the first and last surfaces of the multilayer lens structure are exposed to the air layer, an antireflection coating is formed to prevent Fresnel reflection occurring at the interface with the air layer.

As described above in the embodiments of the present invention, when lenses made of UV resin having a similar refractive index difference are bonded so that an air layer is not interposed, and have an aspherical shape, the occurrence of chromatic aberration is reduced and the refractive index change according to temperature change is similar. level, it is possible to obtain more stable image quality and improved MTF (Modulation Transfer Function) than the conventional lens optical system for photographing.

The description of the present invention described above is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

2,3,4,5,6,7,8,9: interface surfaces
1: input side
13: output side
11, 12: the side of the optical film

Claims (10)

In the photographing lens device having a multilayer UV resin lens structure including a plurality of lenses,
Each lens of the plurality of lenses is made of UV (UltraViolet) resin,
The plurality of lenses are bonded to each other in a form arranged in a line with respect to the optical axis to form bonding surfaces, but the bonding surfaces are formed so that an air layer is not interposed between the lenses in contact with each other,
The joint surface has a rotationally symmetric aspherical shape,
The aspherical surface is
z =

+

+

+

+

+

+ …

z is the segment of the plane perpendicular to the x-axis, K is the conic constant, C is the curvature,

has a shape according to the aspheric equation defined by aspheric coefficients,
In the plurality of lenses, from the input side to the output side along the optical axis, a lens having a relatively high refractive index and a lens having a relatively low refractive index are alternately arranged,
In the plurality of lenses, in an arrangement order from the input side toward the output side along the optical axis, a lens having a relatively high dispersion coefficient and a lens having a relatively low dispersion coefficient are alternately arranged, the arrangement of the plurality of lenses A lens having a larger dispersion coefficient than the two lenses is disposed between the two lenses having a relatively high dispersion coefficient located in the latter part,
the plurality of lenses form eight bonding surfaces, including nine lenses arranged from the input side to the output side along the optical axis;
The eight bonding surfaces, when defining the shape protruding toward the input side as being convex, are in order from the input side toward the output side, convex surface, concave surface, concave surface, convex surface, concave surface, convex surface , A lens device for photographing having a multilayer UV resin lens structure, characterized in that it has a concave surface and a convex surface shape.
delete According to claim 1,
Among the plurality of lenses,
Each of the lenses having a low refractive index may have the same or different refractive indices,
A lens device for photographing having a multilayer UV resin lens structure, characterized in that the lenses having each of the high refractive indexes may have the same or different refractive indices.
According to claim 1,
In order to reduce the occurrence of chromatic aberration and reduce the difference in thermal expansion, the refractive index of the UV resin for manufacturing each lens of the plurality of lenses (

Silver 1.42

A lens device for photographing having a multilayer UV resin lens structure, characterized in that it is within the range of 1.72.
According to claim 1,
In order to reduce the occurrence of chromatic aberration and reduce the difference in thermal expansion, the relative refractive index (

0.94, or

A lens device for photographing having a multilayer UV resin lens structure, characterized in that it is within the range of 1.22.
delete In the photographing lens device having a multilayer UV resin lens structure including a plurality of lenses,
Each lens of the plurality of lenses is made of UV (UltraViolet) resin,
The plurality of lenses are bonded to each other in a form arranged in a line with respect to the optical axis to form bonding surfaces, but the bonding surfaces are formed so that an air layer is not interposed between the lenses in contact with each other,
The joint surface has a rotationally symmetric aspherical shape,
The aspherical surface is
z =

+

+

+

+

+

+ …

z is the segment of the plane perpendicular to the x-axis, K is the conic constant, C is the curvature,

has a shape according to the aspheric equation defined by aspheric coefficients,
In the plurality of lenses, from the input side to the output side along the optical axis, a lens having a relatively high refractive index and a lens having a relatively low refractive index are alternately arranged,
In the plurality of lenses, in an arrangement order from the input side toward the output side along the optical axis, a lens having a relatively high dispersion coefficient and a lens having a relatively low dispersion coefficient are alternately arranged, the arrangement of the plurality of lenses A lens having a larger dispersion coefficient than the two lenses is disposed between the two lenses having a relatively high dispersion coefficient located in the latter part,
the plurality of lenses form 10 bonding surfaces, including 11 lenses arranged from the input side to the output side along the optical axis;
The ten joint surfaces, when defining the shape protruding toward the input side as convex, are in order from the input side to the output side, convex, concave, concave, convex, concave, convex , a concave surface, a convex surface, a concave surface, a convex surface, and a photographing lens device having a multilayer UV resin lens structure, characterized in that it has a convex surface shape.
According to claim 1,
In the order from the input side to the output side,
The first to seventh lenses have a dispersion coefficient (Vd) of 40 or less,
the eighth lens has a dispersion coefficient greater than 40 and less than 50;
The ninth lens is a lens device for photographing having a multilayer UV resin lens structure, characterized in that the dispersion coefficient is 40 or less.
9. The method of claim 8,
The dispersion coefficient of the lens having the relatively high dispersion coefficient is 25 or more and 26 or less,
The lens device for photographing having a multilayer UV resin lens structure, characterized in that the dispersion coefficient of the lens having the relatively low dispersion coefficient is 13 or more and 14 or less.
8. The method of claim 1 or 7,
A lens device for photographing having a multilayer UV resin lens structure, characterized in that an anti-reflection film is formed on the outer surfaces of the two lenses positioned at the outermost sides with respect to the optical axis.

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