KR20210111144A - Lens structure and manufacturing method thereof, and optical sensor including same - Google Patents

Abstract

A lens structure is provided. The lens structure comprises: an upper lens area for condensing light incident from the outside; and a lower collecting area connected to the lower end of the upper lens area and including a plurality of collecting rings spaced apart from each other, wherein the collecting ring has a larger diameter than the lower end of the upper lens area, and protrudes in the radial direction. Between the collecting rings adjacent to each other, collecting grooves recessed from the outer circumferential surface of the collecting ring toward the center may be formed. An object of the present invention is to provide a lens structure with improved sensing sensitivity in a low-temperature environment, a manufacturing method thereof, and an optical sensor including the same.

Description

Lens structure, manufacturing method thereof, and optical sensor including same

The present invention relates to a lens structure, a method for manufacturing the same, and an optical sensor including the same, and more particularly, to a lens structure capable of improving the performance of an optical sensor in a low-temperature environment, a method for manufacturing the same, and an optical sensor including the same it is related

An optical sensor is an electronic device used to detect light, and refers to a device that converts optical energy of visible light or infrared light into an electrical signal. It has a variety of functions such as ambient light sensing, proximity sensing, RGB color sensing, gesture recognition, UV/IR detection, etc., and most are built into mobile devices such as smartphones and tablets to control screen brightness and reduce power consumption to save battery. is being used for

These optical sensors are being used for various purposes in a wide range of fields such as home appliances, automobiles, industrial, home automation, healthcare, entertainment, and security & monitoring. Accordingly, various technologies related to the optical sensor are continuously being researched and developed. For example, in the Republic of Korea Patent Registration No. 10-2103577 (Application No.: 10-2019-0097354, Applicant: Kyungpook National University Industry-Academic Cooperation Foundation), a vacuum tube that provides a space for photoelectrons to move therein is provided on the inner surface of the vacuum tube, A photocathode unit that converts incident light from the outside into first photoelectrons, a scintillator unit that reacts with the first photoelectrons to generate scintillation light, converts the scintillation light into second photoelectrons, and converts the converted second photoelectrons a photomultiplier element that multiplies it to generate an electrical signal; and an electrode disposed on the inner surface of the vacuum tube to focus the first photoelectrons to the scintillator part, wherein the photocathode part, the scintillator part, and the photomultiplier element are sequentially arranged on a movement path of the incident light. wherein the vacuum tube has a spherical upper region and a cylindrical lower region, the photocathode portion and the electrode are positioned in the upper region of the vacuum tube, and the scintillator portion and the photomultiplier element are An optical sensor positioned in the lower region of a vacuum tube is disclosed.

Republic of Korea Patent Registration No. 10-2103577

One technical problem to be solved by the present invention is to provide a lens structure having improved sensing sensitivity in a low-temperature environment, a method for manufacturing the same, and an optical sensor including the same.

Another technical problem to be solved by the present invention is to provide a lens structure having improved sensing sensitivity in a humid environment, a method for manufacturing the same, and an optical sensor including the same.

Another technical problem to be solved by the present invention is to provide a lens structure that is easy to mass-produce, a method for manufacturing the same, and an optical sensor including the same.

Another technical problem to be solved by the present invention is to provide a lens structure with reduced process cost, a method for manufacturing the same, and an optical sensor including the same.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above-described technical problems, the present invention provides a lens structure.

According to an embodiment, the lens structure includes an upper lens area for condensing light incident from the outside, and a lower collecting area connected to a lower end of the upper lens area and including a plurality of collecting rings spaced apart from each other, The collecting ring has a larger diameter than the lower end of the upper lens area, protrudes in a radial direction, and between the collecting rings adjacent to each other, a collecting groove recessed from the outer circumferential surface of the collecting ring toward the center is formed. can

According to an embodiment, the upper lens region may include a convex spherical surface.

According to an embodiment, the surface of the upper lens area and the surface of the lower collecting area may include different affinity for water.

According to an embodiment, the surface of the lower collecting area may include a surface having a higher affinity for water than the surface of the upper lens area.

According to an embodiment, the upper lens region may include PDMS, and the plurality of collection rings included in the lower collection region may include a surface coated with a hydrophilic material.

In order to solve the above-described technical problems, the present invention provides an optical sensor.

According to an embodiment, the optical sensor may include a light sensing element and the lens structure according to the embodiment disposed on the light sensing element to collect light incident from the outside.

According to an embodiment, the light sensing device may include sensing ultraviolet (UV) light through a sensing region including gallium nitride (GaN).

According to an embodiment, the surface of the upper lens region that is disposed on the light sensing element and included in the lens structure may include an increase in temperature in a direction in which a diameter decreases.

In order to solve the above-described technical problems, the present invention provides a method of manufacturing a lens structure.

According to an embodiment, the method of manufacturing the lens structure includes preparing a mold including an accommodating space formed of an inner wall having a step-like stepped structure, and the inner wall of the first area of the accommodating space is the step-shaped step structure. flattening by removing the , the inner wall of the second region of the receiving space remains the step-like structure, providing a base solution containing a polymer in the receiving space to fill the receiving space with the base solution Step, and after curing the base solution to prepare a lens structure, it may include removing the mold from the lens structure.

According to an embodiment, the step of planarizing the inner wall of the first region and leaving the step structure on the inner wall of the second region _{includes an acetyl group (CH 3} CO) in the first region of the accommodation space. It may include providing a planarization solution, and evaporating the planarization solution provided in the first region.

According to one embodiment, in the manufacturing method of the lens structure, after the step of flattening the inner wall of the first region, the inner wall of the second region remains the step structure, before the step of filling the base solution in the accommodation space , masking the inner wall of the first region, providing a coating solution containing a hydrophilic material in the accommodation space to coat the inner wall of the second region with the hydrophilic material, and The method may further include removing the masking.

According to an embodiment, the mold may include ABS.

The lens structure according to an embodiment of the present invention includes an upper lens area for collecting light incident from the outside, and a lower collecting area connected to a lower end of the upper lens area and including a plurality of collecting rings spaced apart from each other. , The collecting ring has a larger diameter than the lower end of the upper lens area, protrudes in the radial direction, and between the collecting rings adjacent to each other, a collecting groove recessed from the outer circumferential surface of the collecting ring toward the center is formed. can Accordingly, the sensor to which the lens structure is applied may have improved sensing efficiency in a low-temperature environment or a high-humidity environment.

1 is a perspective view of a lens structure according to an embodiment of the present invention.
2 is a cross-sectional view of a lens structure according to an embodiment of the present invention.
3 is a cross-sectional view of an upper lens region included in a lens structure according to an embodiment of the present invention.
4 is a cross-sectional view of a lower collecting area included in a lens structure according to an embodiment of the present invention.
FIG. 5 is an enlarged view of part A of FIG. 4 .
6 and 7 are views illustrating a water collecting process of a lens structure according to an embodiment of the present invention.
8 is a view showing an optical sensor to which a lens structure according to an embodiment of the present invention is applied.
9 is a flowchart illustrating a method of manufacturing a lens structure according to an embodiment of the present invention.
10 to 13 are views illustrating a manufacturing process of a lens structure according to an embodiment of the present invention.
14 is a view showing a lens structure according to an embodiment of the present invention.
15 is a photograph of a lens structure according to an embodiment of the present invention.
16 to 21 are photographs of the optical sensor according to the embodiment of the present invention being protected from ice by the lens structure according to the embodiment of the present invention.
22 and 23 are photographs confirming the water trapping effect of the lens structure according to an embodiment of the present invention.
24 and 25 are graphs comparing electrical characteristics of optical sensors according to an embodiment of the present invention and a comparative example.
26 is a photograph and graph showing a temperature difference according to the position of the lens structure according to an embodiment of the present invention.
27 and 28 are photographs and graphs comparing effects according to the thickness of the lens structure included in the optical sensor according to an embodiment of the present invention.
29 and 30 are photographs and graphs comparing effects according to an incident angle of light incident on an optical sensor according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In this specification, when a component is referred to as being on another component, it may be directly formed on the other component or a third component may be interposed therebetween. In addition, in the drawings, thicknesses of films and regions are exaggerated for effective description of technical content.

In addition, in various embodiments of the present specification, terms such as first, second, third, etc. are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Accordingly, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes a complementary embodiment thereof. In addition, in the present specification, 'and/or' is used to mean including at least one of the elements listed before and after.

In the specification, the singular expression includes the plural expression unless the context clearly dictates otherwise. In addition, terms such as "comprise" or "have" are intended to designate that a feature, number, step, element, or a combination thereof described in the specification is present, and one or more other features, numbers, steps, configuration It should not be construed as excluding the possibility of the presence or addition of elements or combinations thereof. Also, in the present specification, the term “connection” is used to include both indirectly connecting a plurality of components and directly connecting a plurality of components.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a perspective view of a lens structure according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a lens structure according to an embodiment of the present invention, and FIG. 3 is an upper lens area included in the lens structure according to an embodiment of the present invention. is a cross-sectional view of, FIG. 4 is a cross-sectional view of the lower collection area included in the lens structure according to an embodiment of the present invention, FIG. 5 is an enlarged view of part A of FIG. 4 , and FIGS. 6 and 7 are embodiments of the present invention It is a view showing a water collecting process of a lens structure according to an example, and FIG. 8 is a view showing an optical sensor to which a lens structure according to an embodiment of the present invention is applied.

1 and 2 , the lens structure 10 according to an embodiment of the present invention may include an upper lens area 100 and a lower collection area 200 . Hereinafter, each configuration will be specifically described.

upper lens area (100)

1 to 3 , the upper lens region 100 may have a convex spherical surface. According to an embodiment, the upper lens region 100 may have a hemispherical shape as shown in FIGS. 1 to 3 . The upper lens area 100 may collect light incident from the outside.

According to an embodiment, the upper lens region 100 may include a polymer having water-repellent properties. For example, the polymer may be PDMS. That is, the upper lens region 100 may be made of PDMS.

As a result, the upper lens region 100 may have a convex spherical surface as described above and may have a water repellent property. Accordingly, when moisture (eg, a droplet) is generated on the upper lens region 100 , the generated moisture flows along the surface of the upper lens region 100 to the upper lens region 100 . ) can be moved to the lower part of the

lower collection area (200)

1 to 5 , the lower collecting area 200 may include a plurality of collecting rings 210 and a plurality of collecting grooves 220 .

The collecting ring 210 may be disposed at a lower end of the upper lens area 100 so as to be connected to a lower end of the upper lens area 100 . _{A diameter r 1} of the collecting ring 210 may be greater than _{a diameter r 0} of the lower end of the upper lens region 100 . Accordingly, the collecting ring 210 may protrude from the lower end of the upper lens region 100 in a radial direction.

The plurality of collecting rings 210 may be disposed to be spaced apart from each other at the lower end of the upper lens area 100 . The collecting groove 220 may be formed between the collecting rings 210 adjacent to each other. The collecting groove 220 may have a shape depressed from the outer circumferential surface of the collecting ring 210 toward the center.

6 and 7 , the moisture moved to the lower end of the upper lens area 100 along the surface of the upper lens area 100 may be collected through the collecting groove 220 . For this reason, when the lens structure 10 according to the embodiment is disposed on the sensing region of the sensor, a problem of a decrease in sensitivity of the sensing region due to moisture may be reduced.

More specifically, in the case of a sensor used in a low-temperature environment or a high-humidity environment, a problem of reduced sensitivity may occur due to ice or moisture generated on the sensing region. However, as described above, when the lens structure 10 according to the embodiment is disposed on the sensing region, ice formation may be delayed due to the characteristic of PDMS having low thermal conductivity. In addition, even if ice or moisture is generated, the sensing region may be protected from ice or moisture because it is collected through the collecting groove 220 . As a result, the sensor in which the lens structure 10 according to the embodiment is disposed on the sensing region may have improved sensing sensitivity in a low-temperature environment or a high-humidity environment.

According to an embodiment, the surface of the lower collecting area 200 may have different affinity for water compared to the surface of the upper lens area 100 . According to an embodiment, the surface of the lower collecting area 200 may have a higher affinity for water than the surface of the upper lens area 100 . For example, a hydrophilic material may be coated on the surface of the lower collecting region 200 . Accordingly, the moisture collecting effect of the collecting groove 220 may be improved.

According to an embodiment, the plurality of collecting rings 210 may have different diameters. More specifically, as shown in FIG. 4 , the diameter of the plurality of collecting rings 210 increases as the distance from the lower end of the upper lens region 100 increases (r ₁ <r ₂ <r ₃ <r _{4 ).} <r ₅ ) can be done. Also, a distance between the plurality of collecting rings 210 adjacent to each other may be different from each other. More specifically, the distance between the plurality of collection rings 210 adjacent to each other increases as the distance from the lower end of the upper lens area 100 increases (d ₁ <d ₂ <d ₃ <), as shown in FIG. 5 . d ₄ < d ₅ ). Accordingly, the moisture collecting effect of the collecting groove 220 may be improved.

Referring to FIG. 8 , the lens structure 10 may be applied to an optical sensor. According to an embodiment, the optical sensor may detect ultraviolet (UV) light through a sensing region including gallium nitride (GaN). In this case, the lens structure 10 may be disposed on the sensing region to improve the sensitivity of the optical sensor. More specifically, the lens structure 10 collects light (eg, ultraviolet rays) incident from the outside through the upper lens region 100 and collects moisture through the lower collection region 200, The sensitivity of the optical sensor may be improved.

According to an embodiment, when the width of the sensing region is 3 mm, the sensing efficiency of the optical sensor may be improved by controlling the incident angle of the incident light to be 0° to 25°. In addition, when the width of the sensing region is 3 mm, the thickness t of the upper lens region 100 is controlled to be 7.73 mm or less, thereby improving the sensing efficiency of the optical sensor. As shown in FIG. 3 , the thickness t of the upper lens region 100 may be defined as a linear distance from the lower end of the upper lens region 100 to the uppermost end of the convex portion.

According to an embodiment, the surface of the upper lens region 100 included in the lens structure 10 disposed on the sensing region may have a different temperature along a direction in which the diameter decreases. More specifically, the temperature of the surface of the upper lens region 100 may increase in a direction in which the diameter decreases. That is, the temperature of the uppermost area A ₁ of the convex portion of the upper lens area 100 may be higher than the temperature of the _{lower end area A 2 of the upper lens area 100 .}

The lens structure 10 according to an embodiment of the present invention is connected to the upper lens area 100 for condensing light incident from the outside, and the lower end of the upper lens area 100 , and includes a plurality of the spaced apart from each other. and the lower collecting area 200 including the collecting ring 210, wherein the collecting ring 210 has a larger diameter than the lower end of the upper lens area 100, protrudes in a radial direction, and is adjacent to each other Between the collecting ring 210, the collecting groove 220, which is depressed from the outer circumferential surface of the collecting ring 210 toward the center thereof, may be formed. Accordingly, the sensor to which the lens structure 10 is applied may have improved sensing efficiency in a low-temperature environment or a high-humidity environment.

Above, the lens structure according to the embodiment of the present invention has been described. Hereinafter, a method of manufacturing a lens structure according to an embodiment of the present invention will be described.

9 is a flowchart illustrating a method of manufacturing a lens structure according to an embodiment of the present invention, FIGS. 10 to 13 are views illustrating a manufacturing process of a lens structure according to an embodiment of the present invention, and FIG. It is a view showing a lens structure according to an embodiment.

9 to 14 , a mold M having an accommodating space AS therein may be prepared ( S100 ). According to an embodiment, the accommodating space AS may be formed of an inner wall having a stepped structure in a step shape as shown in FIG. 10 . According to an embodiment, the accommodation space AS may be formed through a 3D printer. Accordingly, more specifically, filaments may be stacked in a circle through a 3D printer to form the grain of the ring structure portion. For this reason, the lens structure 10 to be described later manufactured using the mold M, as shown in FIG. 2 and described with reference to FIG. 2 , the collecting ring 210, and the collecting groove ( 220) may have.

In addition, the mold M may include ABS.

_{The inner wall W 1} of the first area O ₁ of the accommodation space AS is flattened by removing the step-shaped step structure, and the inner wall W _{of the second area O 2} of the accommodation space AS is ( W ₂ ) may remain in the step structure of the step shape (S200). The first area O ₁ and the second area O ₂ of the accommodation space AS may be different areas divided based on the depth direction of the accommodation space AS.

According to one embodiment, the step of flattening the inner wall (W ₁₎ of said first zone (O _1), and an inner wall (W ₂₎ of the second area (O ₂₎ is remaining a step structure, in FIG. 11 As shown, providing a planarization solution (PL) containing an acetyl group (CH _{3 CO) to the first region (O 1} ) of the accommodation space (AS) _{, and the first region (O 1} ) and evaporating the planarization solution PL provided therein. For example, the planarization solution PL may include acetone. That is, the inner wall W _{1 of the first region O 1} of the accommodating space AS may have the step-like structure removed by the planarization solution PL, so that the inner surface thereof may be planarized.

After the inner wall W ₁ of the first region O ₁ is planarized, and the inner wall W ₂ of the second region O ₂ remains a step structure, a polymer is included in the accommodation space AS. By providing the base solution BL, the accommodating space AS may be filled with the base solution BL (S300). For example, the polymer may include PDMS.

The base solution BL filled in the accommodation space AS may be cured to manufacture the lens structure 10 . In this case, the first region O _{1 having the flattened inner wall W 1} may form the upper lens region 100 included in the lens structure 10 . On the other hand, the second region O _{2 having the stepped inner wall W 2} may form the lower collecting region 200 of the lens structure 10 . In addition, due to the stepped structure of the second region O ₂ , the collecting ring 210 and the collecting groove 220 may be formed.

Thereafter, the mold M may be removed from the lens structure 10 ( S400 ). More specifically, by providing acetone to the mold M, the lens structure 10 may remain, and the mold M may be selectively removed.

According to an embodiment, in the method of manufacturing the lens structure, the inner wall W _{1 of the first region O 1} is planarized, and the inner wall W _{2 of the second region O 2} has a stepped structure. After the remaining step, before the step of filling the base solution BL in the accommodation space AS, masking the inner wall W _{1 of the first region O 1} , the hydrophilicity in the accommodation space AS providing a coating solution comprising a material to provide the hydrophilic material to the inner wall W _{2 of the second region O 2} , and removing the masking in _{the first region O 1 .} may include

Accordingly, the surface of the upper lens region 100 included in the lens structure 10 has a water repellent property, while the surface of the lower collecting region 200 has an inner wall W of _{the second region O 2 . It} may be coated with the hydrophilic material provided in 2) to have hydrophilic properties.

According to another embodiment, in the method of manufacturing the lens structure, after removing the mold from the lens structure 10 , masking the upper lens region 100 , the upper lens region 100 is masked providing a coating solution containing a metal material to the lens structure 10 in a state in which the metal material is provided on the surface of the lower collecting area 200; It may further include the step of removing.

Accordingly, the surface of the upper lens region 100 included in the lens structure 10 may have water-repellent properties, while the surface of the lower collecting region 200 may be coated with the metal material to have hydrophilic properties. .

According to another embodiment, in the method of manufacturing the lens structure, after removing the mold from the lens structure 10 , masking the upper lens area 100 , the upper lens area 100 is Providing a coating solution containing a hydrophilic material (eg, Triton X) to the lens structure 10 in a masked state to provide the hydrophilic material to the surface of the lower collecting region 200, and the It may include removing the masking of the upper lens region 100 .

Accordingly, the surface of the upper lens region 100 included in the lens structure 10 may have a water repellent property, while the surface of the lower collecting area 200 may be coated with the hydrophilic material to have hydrophilic properties. .

Above, a method of manufacturing a lens structure according to an embodiment of the present invention has been described. Hereinafter, specific experimental examples and characteristic evaluation results of the lens structure according to an embodiment of the present invention will be described.

Manufacturing of a lens structure according to an embodiment

A mold including an accommodating space consisting of an inner wall having a stepped structure in a step shape was manufactured using fused deposition modeling (FDM) technology, which is one of the 3D printing technologies. As the material of the mold, ABS was used.

Thereafter, 30 μl of acetone was poured into the first area of the accommodation space and evaporated naturally to planarize an area of the inner wall, and PDMS was filled and cured in the accommodation space to prepare a lens structure.

Finally, the mold from which the lens structure was prepared was placed in acetone, and the mold was removed from the lens structure.

Optical sensor manufacturing according to the embodiment

A device bonded to a dual in-line package (DIP) and having a 4-inch GaN die disposed on a Si wafer is prepared. In the case of a metal electrode disposed on the GaN surface, an aluminum wire was directly bonded to the GaN surface and the metal pad of the DIP, creating a Schottky contact at the aluminum/GaN interface. Ultrasonic Power, Bonding Time, and Force applied to the Wedge Bonding Tool were set to 440 mW, 4 ms, and 40 gf, respectively.

The distance between the two aluminum electrodes was set to 3 mm, and after the PDMS layer was formed on the surface of the GaN photodetector, the lens structure according to the above embodiment was attached to manufacture the optical sensor according to the embodiment.

15 is a photograph of a lens structure according to an embodiment of the present invention.

15A and 15B , the lens structure according to the embodiment was photographed with a scanning electron microscope (SEM) at 500 μm magnification and 100 μm magnification. As can be seen in (a) and (b) of Figure 15, it was confirmed that the upper portion of the lens structure is formed as a lens region having a smooth surface, and a plurality of collecting rings and collecting grooves are formed in the lower portion.

16 to 21 are photographs of the optical sensor according to the embodiment of the present invention being protected from ice by the lens structure according to the embodiment of the present invention.

16 to 19 , after preparing the optical sensor in which the lens structure is not disposed according to the embodiment (Bare GaN) and the optical sensor in which the lens structure (DSLR) according to the embodiment is disposed, a low-temperature environment (- The state change at 20℃~0℃) was shown by taking a top view. More specifically, FIG. 16 is a state immediately after exposure to a low temperature environment, FIG. 17 is a state exposed for 8 minutes in a low temperature environment, and FIG. 18 is a state exposed for 16 minutes in a low temperature environment, 19 is a photograph of a state exposed for 32 minutes in a low-temperature environment.

16 to 19 , in the case of the optical sensor (Bare GaN) in which the lens structure is not disposed according to the embodiment, ice is formed on the surface, but the optical sensor in which the lens structure according to the embodiment is disposed. In the case of , it was confirmed that ice was formed at the lower end of the lens structure. In particular, it was confirmed that ice was not formed in the upper lens area of the lens structure, while ice was formed in the collecting groove of the lower collecting area.

20 and 21 , after preparing the optical sensor in which the lens structure is not disposed according to the embodiment (Bare GaN) and the optical sensor in which the lens structure (DSLR) according to the embodiment is disposed, a low-temperature environment (- The state in which ice was formed at 20 °C to 0 °C) and the state in which the ice melted at room temperature after the formation of ice were respectively photographed and shown. The state in which the ice was formed in a low-temperature environment was photographed and shown in FIG. 20, and the state in which the ice was melted at room temperature is shown in FIG.

As can be seen in FIGS. 20 and 21 , in the case of the optical sensor (Bare GaN) in which the lens structure is not disposed according to the embodiment, not only ice is formed on the sensor surface in a low-temperature environment, but also when the ice is melted at room temperature, the sensor surface Exposure to this moisture could be confirmed. On the other hand, in the case of the optical sensor in which the lens structure according to the embodiment is disposed, it can be confirmed that ice is formed at the lower end of the lens structure in a low-temperature environment, and even when the ice is melted at room temperature, moisture is collected at the lower end of the lens structure was able to confirm that

22 and 23 are photographs confirming the water trapping effect of the lens structure according to an embodiment of the present invention.

22 and 23 , the optical sensor in which the lens structure according to the embodiment is not disposed (leftmost photo), the optical sensor in which the lens structure according to the embodiment is disposed (middle photo), and without a lower collecting area After preparing an optical sensor (rightmost photo) in which a lens structure according to a comparative example with a smooth surface is disposed, the state of moisture generated as ice melts was photographed and shown. 22 is a photograph taken in the lateral direction, and FIG. 23 is a photograph taken in the vertical direction.

As can be seen in FIGS. 22 and 23 , in the case of the optical sensor in which the lens structure is not disposed according to the embodiment, the sensor surface was exposed to moisture as it is, and in the case of the optical sensor in which the lens structure according to the comparative example is disposed, ice It was confirmed that the melted moisture flows down the lens structure, exposing the sensor surface to moisture. On the other hand, in the case of the optical sensor in which the lens structure according to the embodiment is disposed, moisture generated by melting ice is collected at the lower end of the lens structure, and it can be confirmed that the sensor surface is protected from moisture.

As a result, as can be seen in FIGS. 16 to 23 , it can be seen that the lens structure according to the embodiment can effectively collect ice and moisture by the lower collecting area including a plurality of collecting rings and collecting grooves. there was. Accordingly, it can be seen that the lens structure according to the embodiment can improve the sensing sensitivity of the optical sensor in a low-temperature environment or a high-humidity environment.

24 and 25 are graphs comparing electrical characteristics of optical sensors according to an embodiment of the present invention and a comparative example.

24, the optical sensor (with DSLR) according to the embodiment in which the lens structure according to the embodiment is disposed and the optical sensor (without DSLR) according to the comparative example in which the lens structure according to the embodiment is not disposed After preparation, the current (μA) according to the voltage (V) was measured and displayed in the photocurrent condition and the dark current condition, respectively.

As can be seen in FIG. 24 , in the dark current condition, there is no difference in the current (μA) slope according to the Voltage (V) of the optical sensor according to the embodiment and the optical sensor according to the comparative example, but in the photocurrent condition, It was confirmed that the current (μA) slope according to Voltage (V) was higher in the optical sensor according to the comparative example than in the optical sensor according to the comparative example.

Referring to FIG. 25 , after preparing the optical sensor (with DSLR) according to the embodiment and the optical sensor (without DSLR) according to the comparative example, the photocurrent (μA) according to the temperature (°C) was measured and shown.

As can be seen in FIG. 25 , the optical sensor according to the embodiment exhibited a significantly higher photocurrent than the optical sensor according to the comparative example in a low-temperature environment (-20° C. to 0° C.), and an ice-melted environment (20° C. to 30° C.), it was confirmed that the optical sensor according to the embodiment exhibited a significantly higher photocurrent than the optical sensor according to the comparative example.

26 is a photograph and graph showing a temperature difference according to the position of the lens structure according to an embodiment of the present invention.

Referring to FIG. 26 , after preparing the optical sensor according to the embodiment in which the lens structure according to the embodiment is disposed, the temperature according to the position of the lens structure in an environment of -20°C to 0°C was compared. As can be seen in FIG. 26 , it was confirmed that the temperature increased from the lower end (Position #1) to the upper end (Position #3) of the lens structure. That is, it can be seen that the temperature of the upper lens region of the lens structure increases as the diameter decreases.

27 and 28 are photographs and graphs comparing effects according to the thickness of the lens structure included in the optical sensor according to an embodiment of the present invention.

27 and 28, the fraction of rays focused on sensing area according to the thickness (mm) of the upper lens area of the lens structure included in the optical sensor according to the embodiment (Fraction of rays focused on sensing area, %) was measured and expressed. The thickness of the upper lens region is defined as the straight-line distance from the lower end of the upper lens region to the uppermost end of the convex portion, as described with reference to FIG. 3 .

As can be seen in FIGS. 27 and 28 , in the case of the optical sensor according to the embodiment in which the width of the sensing region is 3 mm, the ratio of the focused light on the sensing region based on the thickness of 7.73 mm is significantly reduced. could check Accordingly, it can be seen that, in the optical sensor having a sensing width of 3 mm, the sensing efficiency of the optical sensor can be improved by controlling the thickness of the upper lens region to be 7.73 mm or less.

29 and 30 are photographs and graphs comparing effects according to an angle of incidence of light incident on an optical sensor according to an embodiment of the present invention.

29 and 30 , normalized fractions of rays of light are measured and shown according to an incident angle (°) of light incident on the optical sensor according to the embodiment.

As can be seen in FIGS. 29 and 30 , in the case of the optical sensor according to the embodiment in which the width of the sensing region is 3 mm, the optical sensor according to the comparative example (Bare GaN, It was confirmed that the performance was higher than that of DSLR). Accordingly, it can be seen that, in the optical sensor having a sensing width of 3 mm, the sensing efficiency of the optical sensor can be improved by controlling the angle of the incident light to 0 to 25°.

As mentioned above, although the present invention has been described in detail using preferred embodiments, the scope of the present invention is not limited to specific embodiments and should be construed according to the appended claims. In addition, those skilled in the art will understand that many modifications and variations are possible without departing from the scope of the present invention.

10: lens structure
100: upper lens area
200: lower collection area
210: collecting ring
220: collection home

Claims (12)

an upper lens area for condensing light incident from the outside; and
a lower collecting area connected to the lower end of the upper lens area and including a plurality of collecting rings spaced apart from each other;
The collecting ring has a larger diameter than the lower end of the upper lens area, and protrudes in the radial direction,
A lens structure including a collecting groove recessed in a central direction from an outer circumferential surface of the collecting ring is formed between the collecting rings adjacent to each other.
According to claim 1,
The upper lens region is a lens structure comprising a convex spherical surface.
According to claim 1,
and a surface of the upper lens area and a surface of the lower collecting area have different affinity for water.
4. The method of claim 3,
The surface of the lower collecting area, the lens structure comprising a higher affinity for water than the surface of the upper lens area.
According to claim 1,
The upper lens region includes polydimethylsiloxane (PDMS), and the plurality of collection rings included in the lower collection region includes a surface coated with a hydrophilic material.
light sensing element; and
An optical sensor comprising the lens structure according to claim 1 disposed on the optical sensing element to collect light incident from the outside.
7. The method of claim 6,
The light sensing element is an optical sensor comprising sensing ultraviolet (UV) light through a sensing region including gallium nitride (GaN).
8. The method of claim 7,
The surface of the upper lens region included in the lens structure disposed on the light sensing element, the lens structure including a temperature increasing in a direction in which the diameter decreases.
preparing a mold including an accommodating space formed of an inner wall having a step-like structure;
flattening the inner wall of the first region of the accommodating space by removing the step-shaped step structure, and the inner wall of the second region of the accommodating space remaining the step-shaped step structure;
providing a base solution containing a polymer in the accommodation space, and filling the accommodation space with the base solution; and
After preparing the lens structure by curing the base solution, the method of manufacturing a lens structure comprising the step of removing the mold from the lens structure.
10. The method of claim 9,
The step of planarizing the inner wall of the first region, and the inner wall of the second region remaining a step structure,
providing a planarization solution containing an _{acetyl group (CH 3} CO) to the first region of the accommodation space; and
and evaporating the planarization solution provided in the first region.
10. The method of claim 9,
After the step of flattening the inner wall of the first region and the step structure remaining on the inner wall of the second region, before the step of filling the base solution in the accommodating space,
masking an inner wall of the first region;
coating an inner wall of the second region with the hydrophilic material by providing a coating solution containing a hydrophilic material in the accommodation space; and
The method of manufacturing a lens structure further comprising removing the masking of the inner wall of the first region.
10. The method of claim 9,
The mold, ABS (Acrylonitrile Butadiene Styrene copolymer) method of manufacturing a lens structure comprising a copolymer.

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