KR102045534B1 - Lens comprising doe patterns - Google Patents

Abstract

The lens according to an embodiment of the present invention includes a diffractive optical element (DOE) pattern formed on at least one surface, the DOE pattern includes at least one ring-shaped protrusion, and the protrusion is the highest point and the lowest point in the protrusion direction. And a distance between the highest point and the lowest point in a direction perpendicular to the protruding direction is 100 to 500 nm.

Description

Lens including DOE pattern {LENS COMPRISING DOE PATTERNS}

The present invention relates to a lens, and more particularly to a lens including a diffractive optical element (DOE) pattern.

The refraction angle of light becomes smaller as the wavelength is longer, and becomes larger as the wavelength is shorter. Due to the difference in refraction angle according to the wavelength, the light transmitted through the lens generates chromatic aberration.

On the other hand, the diffraction angle of light becomes smaller as the wavelength becomes shorter, and becomes larger as the wavelength becomes longer. By using these characteristics, a diffractive optical element (DOE) pattern may be formed on the surface of the lens, and chromatic aberration may be reduced.

In order to form a DOE pattern on the surface of the lens, the material is injected into the mold and then injected. In this case, an error may occur in the DOE pattern formed according to the distance or the position of the injection hole into which the material material is injected.

This error degrades the optical performance of the lens and can cause flare or color bleeding.

An object of the present invention is to provide a lens in which a uniform DOE (Diffractive Optical Element) pattern is formed.

The lens according to the embodiment of the present invention includes a DOE (Diffractive Optical Element) pattern formed on at least one surface, the DOE pattern includes at least one ring-shaped protrusion, the protrusion is the highest point and the lowest point in the protrusion direction And a distance between the highest point and the lowest point in a direction perpendicular to the protruding direction is 100 to 500 nm.

The ratio of the longest distance between the highest point and the lowest point of the protrusion relative to the shortest distance between the highest point and the lowest point of the protrusion may be 1 to 4 times.

The difference between the longest distance and the shortest distance may be 200 to 400 nm.

The longest distance may be a distance in a cross section obtained by cutting the lens in a first direction, and the shortest distance may be a distance in a cross section obtained by cutting the lens in a second direction perpendicular to the first direction.

The first direction may be a direction in which a material material is injected onto a mold in order to inject a lens including the DOE pattern.

According to the embodiment of the present invention, a lens having excellent optical performance such as resolution and the like and minimizing flare and color bleeding can be obtained.

1 is a diagram illustrating chromatic aberration correction by a lens in which a DOE pattern is formed.
2 is an example of a mold for injecting a lens in which a DOE pattern is formed.
3 is a cross-sectional view of the lens injected through the mold of FIG. 2 in the A direction, and FIG. 4 is a cross-sectional view of the lens injected through the mold of FIG. 2 in the B direction.
5 illustrates a mold for injecting a lens in which a DOE pattern is formed according to an embodiment of the present invention.
FIG. 6 is a cross-sectional view of the lens injected through the mold of FIG. 5 in the A direction, and FIG. 7 is a cross-sectional view of the lens injected through the mold of FIG. 5 in the B direction.
8 illustrates a mold for injecting a lens in which a DOE pattern is formed according to another embodiment of the present invention.
9 shows a cross-sectional view of a DOE pattern.
10 is a projection of the cross section A direction of the lens injected through the mold according to Figure 1, Figure 11 is a projection of the cross section B direction of the lens injected through the mold according to FIG. 12 is a projection of the A-direction cross section of the lens injected through the mold according to FIG. 5, and FIG. 13 is a projection of the B-direction cross section of the lens injected through the mold according to FIG. 5.
FIG. 14 is a simulation image of the lens injected according to FIG. 1, and FIG. 15 is a simulation image of the lens injected according to FIG. 5.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers, such as second and first, may be used to describe various components, but the components are not limited by the 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 the first component, and similarly, the first component may also be referred to as the second component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination 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. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

1 is a diagram illustrating chromatic aberration correction by a lens in which a DOE pattern is formed.

1 (a) to (c), due to the difference in refractive index according to the wavelength, the light transmitted through the general lens 1 generates chromatic aberration.

On the other hand, the diffraction index according to the wavelength has the opposite characteristics to the refractive index. Accordingly, the lens 2 having the diffraction effect can be used to correct chromatic aberration generated from the normal lens 1. That is, light can be diffracted and condensed at the same time by engraving a fine grating (hereinafter referred to as a DOE (Diffractive Optical Element) pattern) to obtain a diffraction effect on the surface of the lens.

In order to form a DOE pattern on the lens, a mold having a DOE pattern shape may be used.

2 is an example of a mold for injecting a lens in which a DOE pattern is formed.

Referring to FIG. 2, a lens is injected after injecting a material material into the mold 10 through the injection hole 11. Here, the material material is a material forming the lens, and may be a glass or plastic material. The DOE pattern of the lens emitted from the mold 10 may include at least one ring-shaped protrusion.

3 is a cross-sectional view of the lens injected through the mold of FIG. 2 in the A direction, and FIG. 4 is a cross-sectional view of the lens injected through the mold of FIG. 2 in the B direction.

3 and 4, the DOE pattern 110 of the cross section cut in the A direction and the DOE pattern 120 of the cross section cut in the B direction are different. This is because the material is evenly injected into the side of the injection hole, but the material can not be evenly injected into the front of the injection hole due to the viscosity of the material. For this reason, the DOE pattern 110 of the cross section cut in the A direction, which is the side surface of the injection hole, almost matches the shape of the mold, but the DOE pattern 120 of the cross section cut in the B direction, which is the front side of the injection hole, differs from the shape of the mold. Will be gone.

As such, when the shape of the DOE pattern is different according to the position in one lens 100, optical performance such as resolution may be degraded. In addition, when such a lens is applied to a camera, a flare phenomenon or a color bleeding phenomenon may increase.

According to an embodiment of the present invention, it is intended to minimize the difference in shape of the DOE pattern according to the position of the lens. To this end, a lens in which a DOE pattern is formed by using a mold including two or more injection holes is intended.

5 illustrates a mold for injecting a lens in which a DOE pattern is formed according to an embodiment of the present invention.

Referring to FIG. 5, a shape corresponding to a DOE pattern is formed in the mold 20. For example, four injection holes 21, 22, 23, and 24 are connected to an edge of the mold 20. The material is injected into the mold 20 through the injection holes 21, 22, 23, and 24, and then the lens is injected. Accordingly, a DOE pattern corresponding to the shape of the mold 20 may be formed on at least one surface of the lens.

Each injection hole 21, 22, 23, 24 may be connected in a direction perpendicular to the direction toward the center from the edge of the mold. Accordingly, the raw material can be injected in the lateral direction of the mold, and a precise shape can be obtained without constraints on the viscosity of the raw material.

FIG. 6 is a cross-sectional view of the lens injected through the mold of FIG. 5 in the A direction, and FIG. 7 is a cross-sectional view of the lens injected through the mold of FIG. 5 in the B direction.

6 and 7, the DOE pattern 210 of the cross section cut in the A direction and the DOE pattern 220 of the cross section cut in the B direction are similar. As such, by increasing the number of injection holes for injecting the material material and injecting the material material in the lateral direction of the lens, it is possible to minimize the difference in the shape of the DOE pattern according to the position of the lens.

8 illustrates a mold for injecting a lens in which a DOE pattern is formed according to another embodiment of the present invention.

Referring to FIG. 8, four injection holes 31, 32, 33, and 34 are connected to the mold 30, and a material material is injected into the mold 30 through the injection holes 31, 32, 33, and 34. After injection, the lens is ejected. In particular, the structure 35, 36, 37, 38 may be further included near the injection hole of the mold 30 to divide and inject the material material in both directions. Accordingly, the raw material can be injected in the lateral direction of the mold, and a precise shape can be obtained without constraints on the viscosity of the raw material.

Hereinafter, the difference in shape according to the position of the DOE pattern according to an embodiment of the present invention will be described in detail.

9 shows a cross-sectional view of a DOE pattern.

Referring to FIG. 9, the DOE pattern 900 may include at least one ring-shaped protrusion 910, 920, and 930 based on the center of the lens. Each protrusion has a highest point HP and a lowest point LP with respect to the direction of protrusion H. Here, the highest point HP means the point with the highest height on the cross section of the protrusion, and the lowest point LP means the point with the lowest height on the cross section of the same protrusion. The horizontal distance D between the highest point HP and the lowest point LP of the protrusion may be used to predict whether the DOE pattern is finely formed. Here, the horizontal distance D means a distance in the direction R perpendicular to the protruding direction H. FIG. The closer the DOE pattern is to the mold, the shorter the horizontal distance D between the highest point HP and the lowest point LP. On the other hand, it is possible to predict whether the shape of the DOE pattern is uniform by using the difference in the horizontal distance (D) for each position of the lens.

10 is a projection of the cross section A direction of the lens injected through the mold according to Figure 1, Figure 11 is a projection of the cross section B direction of the lens injected through the mold according to FIG. 12 is a projection of the A-direction cross section of the lens injected through the mold according to FIG. 5, and FIG. 13 is a projection of the B-direction cross section of the lens injected through the mold according to FIG. 5.

Referring to FIG. 10, the horizontal distance D between the highest point and the lowest point is 162 nm. Referring to FIG. 11, the horizontal distance D between the highest point and the lowest point is 785 nm. At this time, the difference in the horizontal distance in the A direction and the B direction is 600 nm or more (785 nm to 162 nm), and the ratio of the longest horizontal distance (785 nm) to the shortest horizontal distance (162 nm) is 4.8 times or more.

In contrast, referring to FIG. 12, the horizontal distance D between the highest point and the lowest point is 138 nm. Referring to FIG. 13, the horizontal distance D between the highest point and the lowest point is 436 nm. At this time, the difference in the horizontal distance in the A direction and the B direction is 300 nm or less (436 nm to 138 nm), and the ratio of the longest horizontal distance (436 nm) to the shortest horizontal distance (138 nm) is 4 times or less.

As described above, according to the embodiment of the present invention, a lens having a horizontal distance between the highest point and the lowest point of the protrusion of the DOE pattern is 100 nm to 500 nm, preferably 120 nm to 470 nm, and more preferably 130 nm to 440 nm. In addition, a lens having a ratio of 1 to 4 times, preferably 3 to 3.5 times the ratio of the longest horizontal distance to the shortest horizontal distance between the highest point and the lowest point of the protrusion of the DOE pattern can be obtained. Further, a lens having a difference between the longest horizontal distance and the shortest horizontal distance between the highest point and the lowest point of the protrusion of the DOE pattern is 600 nm or less, preferably 200 nm to 400 nm or less, and more preferably 250 nm to 350 nm or less.

As such, when the difference in the shape of the DOE pattern according to the position of the lens is minimized, the optical performance of the lens may be increased, and flare and color bleeding may be reduced.

FIG. 14 is a simulation image of the lens injected according to FIG. 1, and FIG. 15 is a simulation image of the lens injected according to FIG. 5.

Referring to FIG. 14, when the average brightness was fixed at 40, the exposure time was found to be 8 ms. 15, when the average brightness is fixed to 40, the exposure time is found to be 19 ms.

That is, when the difference between the longest horizontal distance and the shortest horizontal distance is reduced from about 600 nm to about 300 nm, it can be seen that the exposure time is more than doubled at the same brightness. This means that the flare phenomenon is reduced in a high brightness light source.

The lens according to the embodiment of the present invention may be applied to the camera module. In particular, by using this, it is possible to obtain a high performance camera module embedded in a portable terminal of miniaturization trend.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

20: mold
21, 22, 23, 24: inlet
900: DOE pattern
910, 920, 930: protrusions

Claims (5)

It includes a diffractive optical element (DOE) pattern formed on at least one side,
The DOE pattern includes at least one ring-shaped protrusion,
The projection includes the highest point and the lowest point in the projecting direction, the ratio of the longest distance between the highest point and the lowest point of the protrusion relative to the shortest distance between the highest point and the lowest point in the direction perpendicular to the projecting direction is 1 to 4 times the lens. . The method of claim 1,
And a distance between the highest point and the lowest point in a direction perpendicular to the protruding direction. The method of claim 1,
And the difference between the longest distance and the shortest distance is 200 to 400 nm. The method of claim 1,
And the longest distance is a distance in a cross section obtained by cutting the lens in a first direction, and the shortest distance is a distance in a cross section obtained by cutting the lens in a second direction perpendicular to the first direction. The method of claim 4, wherein
The first direction is a direction in which a material material is injected onto a mold in order to eject the lens including the DOE pattern.

Images