KR20170028169A - Lens and lens assembly comprising the same - Google Patents

Abstract

A lens according to an embodiment of the present invention includes a substrate having an etched surface and a hydrophilic coating layer formed on the surface. Accordingly, it is possible to obtain a lens having superhydrophilic characteristics and excellent abrasion resistance, a lens assembly including the same, and a camera module.

Description

≪ Desc / Clms Page number 1 > LENS AND LENS ASSEMBLY COMPRISING THE SAME

The present invention relates to a lens, 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 hydrophilic coated, water droplets on the surface of the lens spread widely, which can solve problems such as scattering of light, frost, fogging, contamination, image bending and the like.

However, when a hydrophilic solution is coated on the surface of the lens, the hydrophilic solution is not easily coated due to the surface resistance of the lens. Also, even if the coating is applied, the bonding force between the lens surface and the hydrophilic coating layer is low, so that the hydrophilic coating layer tends to be worn, and it is difficult to obtain the superhydrophilic characteristic.

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.

A lens according to an embodiment of the present invention includes a substrate having an etched surface and a hydrophilic coating layer formed on the surface.

The hydrophilic coating layer may be bonded to the activated oxygen on the surface of the substrate.

The water contact angle on the hydrophilic coating layer may be 10 deg. Or less.

The water contact angle on the hydrophilic coating layer may be 5 DEG or less.

The water contact angle on the hydrophilic coating layer may be 15 째 or less after performing a wear resistance test for 1,500 times with a force of 4.9 N using a canvas cloth having a length of 100 賊 5 mm.

The surface of the substrate can be etched by plasma treatment.

The plasma treatment may be performed in at least one of an argon and oxygen atmosphere, a vacuum oxygen atmosphere, and a compressed air atmosphere.

The hydrophilic coating layer may include a polymer having a hydrophilic functional group.

The hydrophilic functional group may be selected from the group consisting of a hydroxyl group, an amino group and an epoxy group.

The hydrophilic coating layer may include an element selected from the group consisting of Si, K, P, Na, Al, Li, Sn and Pt.

A lens assembly according to an exemplary embodiment of the present invention includes a housing, a lens accommodated in the housing, and a retainer coupled to one end of the housing and supporting the lens, And a hydrophilic coating layer formed on the surface.

According to the embodiments of the present invention, it is possible to obtain a lens, a lens assembly and a camera module including the lens that can stably maintain optical characteristics and field of view even in an external environment such as rain, fog, and the like. In particular, the abrasion resistance is high, and the functionality and reliability can be improved even in a high temperature and high humidity environment.

1 shows 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.
Figure 3 is a surface of a substrate according to one embodiment of the present invention.
4 is a flowchart illustrating a method of manufacturing a lens having a hydrophilic coating layer according to an embodiment of the present invention.
Figs. 5 to 6 show images taken with lenses manufactured according to Comparative Examples 1 and 2. Fig.
Figs. 7 to 10 show screens photographed with lenses manufactured according to Examples 1 to 4. Fig.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

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. Here, the substrate 122 may be glass or plastic, and the substrate 122 may have an etched surface as illustrated in Fig. The etched surface of the substrate 122 may be obtained by plasma treatment of the substrate 122. When the substrate 122 is plasma-treated, the surface of the substrate 122 is unevenly etched as shown in Fig. 3, and the hydroxyl group (-OH group) on the surface of the substrate 122 can be activated.

When the surface of the base material 122 is etched and the hydroxyl group is activated, the binding force with the hydrophilic coating solution is increased due to the activated hydroxyl group, so that the hydrophilic property of the lens 120 is enhanced and the abrasion resistance is improved.

Accordingly, when water is dropped on the surface of the lens 120, that is, on the hydrophilic coating layer 124, the contact angle, which is a spreading angle of water, can be maintained at 10 degrees or less, preferably 5 degrees or less. When the angle at which the water spreads on the surface of the lens 120 is 10 DEG or less, a super-hydrophilic property is obtained, so that a clear visual field can be secured even in an environment such as rain, fog, and the like.

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 may be covalently bonded, for example, by an activated hydroxyl group on the surface of the substrate 122. That is, the hydrophilic coating layer 124 can be covalently bonded to the surface of the substrate 122 with oxygen. As a result, the bonding strength between the base material 122 and the hydrophilic coating layer 124 is strengthened, so that the durability and the wear resistance can be enhanced.

At this time, 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.

4 is a flowchart illustrating a method of manufacturing a lens having a hydrophilic coating layer according to an embodiment of the present invention.

Referring to FIG. 4, after the surface of the substrate 122 is cleaned (S100), a plasma treatment is performed (S110). Here, the substrate 122 may be, for example, glass or plastic. The plasma treatment may be performed at atmospheric pressure or vacuum conditions. For example, the plasma treatment may be performed in at least one of an argon and oxygen atmosphere, a vacuum oxygen atmosphere, and a compressed air atmosphere.

Thus, the surface of the substrate 122 is etched, and the hydroxyl group (-OH) on the surface of the substrate 122 is activated.

Then, the surface of the substrate 122 is coated with a hydrophilic coating solution (S120). At this time, the coating can be applied by techniques such as dip-coating, spray coating, and hand coating.

According to one embodiment of the present invention, the hydrophilic coating liquid may include a polymer having a hydrophilic functional group. Here, the hydrophilic functional group may be selected from the group consisting of a hydroxyl group, an amino group and an epoxy group. At this time, the hydrophilic coating liquid may further include at least one of a nonionic surfactant and a solvent. As such, when the hydrophilic coating layer 124 includes a polymer having a hydrophilic functional group, the surface of the lens 120 may have wettability or hydrophilicity.

According to another embodiment of the present invention, the hydrophilic coating liquid may contain an organic oxide. Here, the organic oxide may be an oxide including an element selected from the group consisting of Si, K, P, Na, Al, Li, Sn and Pt. For example, the organic oxide may be a silicone oil. At this time, the hydrophilic coating liquid may further include at least one of a nonionic surfactant and a solvent. The solvent can be water or alcohol-based. As described above, when the hydrophilic coating layer 124 contains an inorganic oxide, the hydrophilicity of the surface of the lens 120 can be increased.

When the surface of the substrate is subjected to plasma treatment and then coated with a hydrophilic coating liquid, the adhesion force between the hydrophilic coating liquid and the surface of the substrate is high, so that water droplets and dust are not easily applied on the surface of the lens, A clear view can be secured. Particularly, even when the hydrophilic coating liquid contains an inorganic oxide, the adhesion between the surface of the substrate and the hydrophilic coating liquid can be increased.

Hereinafter, contact angle, transmittance and contact angle after wear resistance test of a lens having a hydrophilic coating layer on its surface were measured according to Comparative Examples and Examples.

Comparative Example 1 is an example in which a hydrophilic coating layer is not formed on a glass surface, and Comparative Example 2 is an example in which a hydrophilic coating layer is formed on a substrate without pretreating the glass surface. In Example 1, after the glass surface was cleaned, N ₂ gas of 15 to 20 l / min was plasma-treated once at a rate of 100 to 200 mm / sec at a height of 5 mm by using a plasma apparatus of 600 to 900 W, To form a hydrophilic coating layer. In Example 2, after the glass surface was cleaned, compressed air was plasma-treated 1 to 2 times at a height of 5 to 15 mm at a speed of 100 to 200 mm / sec using a 900 W plasma apparatus, and a hydrophilic coating layer was formed by a spraying process Yes. Example 3 is an example in which a glass surface is cleaned, a plasma treatment is performed in a vacuum chamber using plasma equipment of 300 to 400 W, and a hydrophilic coating layer is formed by a spraying process. In Example 4, after washing the glass surface, argon (Ar) at 15 to 20 l / min and oxygen (O ₂ ) gas at 20 to 100 ml / min were mixed using plasma equipment of 400 to 500 W, sec at a speed of 4 to 5 mm, and then a hydrophilic coating layer is formed by a spraying process. At this time, the hydrophilic coating solution for forming the hydrophilic coating layer contained 5 wt% of silicone oil, 15 wt% of nonionic surfactant, and 80 wt% of water, and the hydrophilic coating layer had a thickness of 3 nm.

In order to compare Comparative Examples 1 to 2 and Examples 1 to 4, water was sprayed on the surface of the lens manufactured according to Comparative Examples 1 to 2 and Examples 1 to 4, and the contact angle at which the water spreads was measured with a contact angle measuring device analyzer). Then, in order to compare the contact angles after the abrasion resistance test, the surfaces of the lenses manufactured according to Comparative Examples 1 to 2 and Examples 1 to 4 were worn for 1,500 times with a force of 4.9 N using a 100 ± 5 mm canvas cloth The contact angle at which water was sprayed and water was spread was measured using a contact angle meter. Then, in order to test the field of view of the lens, the surface of the lens manufactured according to Comparative Examples 1 to 2 and Examples 1 to 4 was exposed to distilled water at 70 캜 for 5 seconds, and then the photograph was taken.

Table 1 shows contact angles, transmittances and contact angles of the lenses manufactured according to Comparative Examples 1 to 2 and Examples 1 to 4 after the test for the transmittance and abrasion resistance, and Figs. 5 to 6 show images taken with lenses manufactured according to Comparative Examples 1 and 2 And Figs. 7 to 10 show screens taken with the lenses manufactured according to the first to fourth embodiments.

test item Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Contact angle 50˚ 15˚ 13˚ 7˚ 9˚ 4 Transmittance 85% 88% or more over 90 91% or more over 90 91% or more Contact angle after abrasion resistance test - 30˚ 15.8 ˚ 12.8 ˚ 10.6 ˚ 7.3 ˚

In Table 1, the contact angles and the contact angles after the abrasion test in Examples 1 to 4, which were plasma-treated and hydrophilic coated, compared to Comparative Examples 1 and 2 in which the surface of the lens was not hydrophilic coated or hydrophilic coated without plasma treatment And it is seen that it is high. 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. Thus, it can be seen that the hydrophilic properties in Examples 1 to 4 are better than those in Comparative Examples 1 and 2. Further, in Example 2 in which plasma treatment was performed with compressed air, in Example 3 in which plasma treatment with vacuum oxygen was performed, in Example 4 in which plasma treatment was performed with argon and oxygen gas, the contact angle of water was 10 ° or less, The contact angle of water is 15 ˚ or less. Particularly, in Example 4 in which the plasma treatment was performed with argon and oxygen gas, the water contact angle was 5 ° or less and the water contact angle after the abrasion test was 10 ° or less.

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 (11)

A surface-etched substrate, and
The hydrophilic coating layer
/ RTI > The method according to claim 1,
Wherein the hydrophilic coating layer is bonded to the activated oxygen on the surface of the substrate. The method according to claim 1,
And the water contact angle on the hydrophilic coating layer is 10 DEG or less. The method of claim 3,
Wherein the water contact angle on the hydrophilic coating layer is 5 占 or less. The method according to claim 1,
A lens having a water contact angle of 15 째 or less on the hydrophilic coating layer after 1,500 abrasion tests at a force of 4.9 N using a canvas cloth having a length of 100 賊 5 mm. The method according to claim 1,
Wherein the surface of the substrate is etched by a plasma treatment. The method according to claim 6,
Wherein the plasma treatment is performed in at least one of an argon and oxygen atmosphere, a vacuum oxygen atmosphere, and a compressed air atmosphere. The method according to claim 1,
Wherein the hydrophilic coating layer comprises a polymer having a hydrophilic functional group. 9. The method of claim 8,
Wherein the hydrophilic functional group is selected from the group consisting of a hydroxyl group, an amino group and an epoxy group. The method according to claim 1,
Wherein the hydrophilic coating layer comprises an oxide comprising an element selected from the group consisting of Si, K, P, Na, Al, Li, Sn and Pt. 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
A surface-etched substrate, and
The hydrophilic coating layer
≪ / RTI >

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