KR20170068265A

KR20170068265A - Lens and lens assembly comprising the same

Info

Publication number: KR20170068265A
Application number: KR1020150175250A
Authority: KR
Inventors: 이현지; 노진미; 이영재; 이희정; 배석
Original assignee: 엘지이노텍 주식회사
Priority date: 2015-12-09
Filing date: 2015-12-09
Publication date: 2017-06-19

Abstract

According to an embodiment of the present invention, there is provided a substrate comprising: a substrate; And a hydrophilic coating layer formed on the substrate and having a hydrophilic functional group and including a polymer having a molecular weight of 70,000 to 120,000.

Description

&Lt; Desc / Clms Page number 1 > LENS AND LENS ASSEMBLY COMPRISING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lens and a lens assembly including the same, and more particularly, to a lens having a coating layer formed on a surface thereof and a lens assembly including the same.

The lens disposed at the outermost one of the lens assemblies included in the camera module is exposed to the external environment. Particularly, when the camera module is mounted on a vehicle, the optical characteristics of the camera module may deteriorate due to rain, mist, light reflection, dust, or the like, or the visual field may be insufficient.

Accordingly, there is an attempt to coat the lens of the camera module with a hydrophilic coating layer. When the lens surface of the camera module is coated with a hydrophilic material, problems such as light scattering, frost, fogging, contamination, and image bending can be solved.

The lens surface can be coated with inorganic particles for hydrophilic coating. However, according to this method, since the bonding force between the base material and the hydrophilic coating layer is low, the hydrophilic coating layer tends to be worn, and it is difficult to obtain superhydrophilic characteristics.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens and a lens assembly including the same that can stably maintain optical characteristics and field of view even in an external environment such as rain and fog.

It is another object of the present invention to provide a lens and a lens assembly including the lens, which can improve the durability and reliability while securing a contact angle characteristic with superhydrophilic characteristics.

The contact angle on the hydrophilic coating layer may be 15 degrees or less.

After the abrasion resistance test is performed 1,500 times with a force of 4.9 N by using a canvas cloth having a length of 100 ± 5 mm, the contact angle change amount on the hydrophilic coating layer may be 5 ° or less.

The substrate and the hydrophilic coating layer may be covalently bonded.

The substrate and the hydrophilic coating layer may be covalently bonded to O of the substrate by Si or C of the hydrophilic coating layer.

The hydrophilic functional group may be selected from the group consisting of a hydroxyl group (-OH), an amino group (-NH3) and an epoxy group.

According to another embodiment of the present invention, there is provided a lens holder comprising a housing, a lens accommodated in the housing, and a retainer coupled to one end of the housing and supporting the lens, the lens comprising a base, And a hydrophilic coating layer containing a polymer having a molecular weight of 70,000 to 120,000.

The contact angle on the hydrophilic coating layer may be 15 degrees or less.

According to the embodiment, optical characteristics and field of view can be stably secured even in an external environment such as rain, fog, and the like.

Further, it is possible to secure a contact angle characteristic having super hydrophilic characteristics, and to improve durability and reliability.

1 is an exploded view of a lens assembly according to an embodiment of the present invention,
2 is a cross-sectional view of a lens according to an embodiment of the present invention,
3 is a schematic view of a lens hydrophilic coated with a polymer having a molecular weight of 70,000 to 120,000 according to an embodiment of the present invention,
FIG. 4 is a view showing a hydrophilic coating method of FIG. 3,
5 is a diagram for comparing the hydrophilic characteristics of the lens according to the comparative example and the example,
6 is a view for comparing wear resistance characteristics of the lens according to the comparative example and the example,
7 is a SEM of a lens according to Comparative Examples and Examples

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

1 shows an exploded view of a lens assembly according to an embodiment of the present invention.

1, the lens assembly 100 includes a housing 110, a lens 120 accommodated in the housing 110, and a retainer (not shown) coupled to one end of the housing 110 and supporting the lens 120. [ , 130).

Here, the lens 120 may include a plurality of lenses sequentially arranged from the object side to the image side. Each lens may have a positive refracting power or a negative refracting power, and may have a convex surface, a concave surface, or a meniscus shape. The refracting power and surface shape of the plurality of lenses can be variously combined according to the required focal length or the like.

The lens assembly according to an embodiment of the present invention may be included in a camera module, for example, a camera module for a vehicle. The camera module may include a lens assembly, a filter, an image sensor, and a printed circuit board according to an embodiment of the present invention. For this, though not shown, a filter, an image sensor, and a printed circuit board may be sequentially arranged behind the lens assembly. That is, an image sensor may be mounted on a printed circuit board, and a filter may be formed on the image sensor. Here, the image sensor can be connected to the printed circuit board by a wire. The image sensor may be, for example, a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor) sensor. The filter may be an infrared (IR) filter. The filter can block near-infrared rays, for example, light having a wavelength of 700 nm to 1100 nm, from light incident into the camera module.

On the other hand, of the plurality of lenses, the lens closest to the object side (hereinafter referred to as the outermost lens) is exposed to the outside. When one side of the lens is exposed to an external environment such as rain, fog, etc., the optical characteristics of the camera module may be deteriorated or the visual field may be insufficient.

Accordingly, there is an attempt to coat the lens of the camera module with a hydrophilic coating layer. When a hydrophilic coating is applied, water droplets on the lens are spread. Thus, fogging or water condensation on the surface of the lens can be prevented.

2 is a cross-sectional view of a lens according to an embodiment of the present invention.

2, the lens 120 includes a substrate 122 and a hydrophilic coating layer 124 formed on the substrate 122 and including a polymer having a hydrophilic functional group and a molecular weight of 70,000 to 120,000. And the like.

Here, the substrate 122 may be glass or plastic, and the hydrophilic functional group contained in the polymer may be selected from the group consisting of a hydroxyl group (-OH), an amino group (-NH3) and an epoxy group. If the hydrophilic coating layer 124 comprises a polymer having a hydrophilic functional group, the surface of the lens 120 may have wettability or hydrophilicity. Particularly, when the hydrophilic functional group is bonded to each monomer forming the polymer, the density of the hydrophilic functional group in the hydrophilic coating layer 124 can be increased, so that the hydrophilic coating layer 124 can have a superhydrophilic property.

Here, the substrate 122 and the hydrophilic coating layer 124 may be covalently bonded to each other. The substrate 122 and the hydrophilic coating layer 124 can be covalently bonded, for example, by O of the substrate 122 and Si or C of the hydrophilic coating layer 124. To this end, when the substrate 122 is a glass substrate, the surface of the substrate 122 can be plasma treated, halogenated alkyl treatment, or acid base treatment to activate the hydroxyl group (-OH). Thus, the bonding force between the base material 122 and the hydrophilic coating layer 124 can be strengthened.

The hydrophilic coating layer 124 includes a polymer having a molecular weight of 70,000 to 120,000.

As the molecular weight of the polymer constituting the hydrophilic coating layer 124 is smaller, the abrasion resistance property is improved, but the hydrophilic property is lowered. When the molecular weight of the polymer is larger, the hydrophilic property is improved but the abrasion resistance property is lowered. Therefore, by setting the molecular weight of the polymer constituting the hydrophilic coating layer 124 to 70,000 to 120,000, the contact angle on the hydrophilic coating layer 124 can be maintained to 15 ° or less while maintaining excellent abrasion resistance.

The hydrophilic coating layer 124 according to the embodiment was subjected to an abrasion resistance test with a force of 4.9 N using a canvas cloth having a length of 100 ± 5 mm for 1,500 times, and then the change in contact angle on the hydrophilic coating layer was measured to be 5 ° or less.

The thickness of the hydrophilic coating layer 124 may be 1 nm to 100 nm, preferably 2 nm to 10 nm. When the thickness of the hydrophilic coating layer 124 is less than 1 nm, the hydrophilic coating layer 124 tends to be worn and the hydrophilic property may deteriorate. Accordingly, the reliability of the camera module can be lowered. On the other hand, if the thickness of the hydrophilic coating layer 124 is more than 100 nm, the hydrophilic coating layer 124 may be peeled off, so that the hydrophilic property may be deteriorated.

FIG. 3 is a schematic view of a lens coated with a hydrophilic polymer having a molecular weight of 70,000 to 120,000 according to an embodiment of the present invention, and FIG. 4 is a view showing a hydrophilic coating method of FIG.

Referring to FIG. 3, a polymer including a hydrophilic functional group is bonded on a substrate 122.

Referring to FIG. 4, the substrate 122 is first cleaned and then activated. Plasma treatment, alkyl halide treatment or acid base treatment may be performed to activate the substrate 122.

Thereafter, a monomer having a hydrophilic functional group (-R) is added on the surface of the substrate 122, whereby the monomer is bonded onto the surface of the activated substrate 122. For example, when the surface of the base material 122 is treated with an alkyl halide as shown in Fig. 4, -Cl (chloride) is activated on the surface of the base material 122. When a monomer having a double bond is put on the surface of the activated substrate 122, the double bond of the monomer is activated to separate -Cl, and the monomer and the surface of the substrate 122 are bonded. When the surface of the substrate 122 to which the monomer is bonded is reactivated, a monomer having a hydrophilic functional group is added, and the monomer is bonded again on the surface of the activated substrate 122. When this process is repeatedly carried out, a monomer having a hydrophilic functional group is polymerized to form a comb-like polymer having a desired molecular weight. Here, the hydrophilic functional group may be selected from the group consisting of, for example, a hydroxyl group, an amino group and an epoxy group. As described above, when the monomer is repeatedly added to the surface of the base material 122 and polymerized with the polymer, the density of the hydrophilic functional group in the hydrophilic coating layer 124 is higher than when the polymer is directly bonded onto the surface of the base material 122 It is possible to obtain excellent hydrophilic characteristics, and by controlling the molecular weight to 70,000 to 120,000, desired hydrophilic characteristics and abrasion resistance characteristics can be secured.

Table 1 shows the contact angle, transmittance and abrasion resistance test results of the lens according to the molecular weight of the polymer forming the hydrophilic coating layer on the surface and the hydrophilic coating layer on the surface according to the comparative example and the example. 6 is a view for comparing the abrasion resistance characteristics of the lenses according to Comparative Examples 1 to 3 and Examples according to Table 1, and Fig. 7 is a graph for comparing the abrasion resistance characteristics SEM of the lenses according to Comparative Examples 2 to 3 and Examples.

Comparative Example 1 is an example in which a hydrophilic coating layer is not formed on a glass surface, and in Comparative Example 2, a monomer containing a hydroxyl group as a hydrophilic functional group is polymerized after activation of a glass substrate to form a hydrophilic coating layer having a molecular weight of from 40,000 to less than 70,000 Comparative Example 3 is a result of forming a hydrophilic coating layer having a molecular weight of more than 120,000 but less than 170,000 by polymerizing a monomer containing a hydroxyl group as a hydrophilic functional group after activating the glass substrate, A monomer having a hydroxyl group as a hydrophilic functional group is polymerized to form a hydrophilic coating layer having a molecular weight of 70,000 to 120,000.

In order to compare Comparative Examples 1 to 3 and Examples, water was sprayed onto the surface of the lens manufactured according to Comparative Examples 1 to 3 and Example, and then the contact angle at which the water spread was measured using a contact angle analyzer Respectively. In order to compare the contact angles after the abrasion resistance test, on the surface of the lens manufactured according to Comparative Examples 1 to 3 and Example, a canvas cloth having a length of 100 ± 5 mm was used, and 500 times, 1,000 times, 1,500 times And the contact angle at which the water was spread was measured using a contact angle meter.

When the hydrophilic coating layer having a molecular weight of 70,000 to 120,000 was formed while the hydrophobic coating layer was not formed, the water contact angle of the hydrophobic coating layer was 4 ° to 12 ° Respectively. The contact angle is an angle at which the water falling on the surface of the lens is spread, and the lower the angle, the better the hydrophilic property.

In addition, when the hydrophilic coating layer having a molecular weight of 70,000 to 120,000 was formed while the water contact angle was measured at 7 ° to 12 ° in the case of a molecular weight of more than 40,000 and less than 70,000, 12 < / RTI >

In the case of Comparative Example 3, when the molecular weight was more than 120,000 but less than 170,000, the water contact angle characteristics were measured to be similar to those of the Examples. However, in the case of Comparative Example 3, the water contact angle after the 500-time abrasion test was 12 ° to 19 ° after the abrasion resistance test, the water contact angle after the 1000-time abrasion was 13 ° to 25 °, 19 ° to 28 °. That is, in the case of Comparative Example 3, it can be seen that the contact angle of water becomes very large according to the wear, which means that the hydrophilicity of the lens is remarkably lowered according to the wear.

On the other hand, in the case of the shoe-making example, the water contact angle after the 500th abrasion test was measured as 5 ° to 12 ° after the abrasion test, the water contact angle after the 1000th abrasion was 7 ° to 14 °, ˚ to 16˚. That is, in the examples, it can be seen that the contact angle of water did not change after 500 times of abrasion test, and that the change of the contact angle of water even after 1,500 abrasions was measured to be 5˚ or less. This is a result indicating that the polymer having a hydrophilic coating layer has a molecular weight of from 70,000 to 120,000, thereby securing excellent hydrophilicity and wear resistance.

Referring to FIG. 5, in Comparative Examples 2 to 3, in which a hydrophilic coating layer was formed, and in Examples, compared to the case where a hydrophilic coating layer was not formed according to Comparative Example 1, clear images could be obtained due to excellent hydrophilic properties.

However, referring to FIG. 6, in the case of Comparative Examples 2 to 3 after 1,500 times of abrasion, the water contact angle characteristics remarkably lowered and blurry images were photographed. On the other hand, in the case of Examples, excellent contact angle characteristics were secured even after abrasion, I could.

Referring to FIG. 7, it can be seen that the difference in shape of the lens surface according to the comparative examples 2 to 3 and the example is not largely shown, but shows a uniform surface shape.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

100: lens assembly
110: Housing
120: lens
130: retainer
122: substrate
124: hydrophilic coating layer

Claims

materials; And
A hydrophilic coating layer formed on the substrate and having a hydrophilic functional group and including a polymer having a molecular weight of 70,000 to 120,000,
/ RTI >

The method according to claim 1,
Wherein the hydrophilic coating layer has a contact angle of 15 DEG or less.

3. The method of claim 2,
A lens having a contact angle variation of 5 占 or less after performing an abrasion resistance test for 1,500 times with a force of 4.9N using a canvas cloth having a length of 100 占 5mm.

The method according to claim 1,
Wherein the substrate and the hydrophilic coating layer are covalently bonded.

5. The method of claim 4,
Wherein the base material and the hydrophilic coating layer are covalently bonded to O of the substrate by Si or C of the hydrophilic coating layer.

The method according to claim 1,
Wherein the hydrophilic functional group is selected from the group consisting of a hydroxyl group (-OH), an amino group (-NH3) and an epoxy group.

housing,
A lens housed in the housing, and
And a retainer that is coupled to one end of the housing and supports the lens,
The lens
Description, and
A hydrophilic coating layer formed on the substrate and having a hydrophilic functional group and including a polymer having a molecular weight of 70,000 to 120,000,
&Lt; / RTI >

9. The method of claim 8,
Wherein a change in contact angle on the hydrophilic coating layer after the abrasion resistance test is performed 1,500 times with a force of 4.9 N using a 100 ± 5 mm canvas cloth is 5 ° or less.