Composition for varifocal lens comprising single-chain cyclohexane-based eco-friendly plasticizer and method for manufacturing lens using same

Abstract

The present invention relates to a composition for a varifocal lens comprising a single-chain cyclohexane-based eco-friendly plasticizer, and a method for manufacturing a lens using same. A varifocal lens with excellent performance can be implemented by using, as a plasticizer, cyclohexyl butyrate or cyclohexyl hexanoate that is eco-friendly and less harmful to the human body.

Description

Composition for variable focus lenses containing a single-chain cyclohexane-based eco-friendly plasticizer and method for manufacturing a lens using the same

[0001] The present invention relates to a composition for a variable focus lens comprising a single-chain cyclohexane-based eco-friendly plasticizer and a method for manufacturing a lens using the same. By using cyclohexyl butyrate or cyclohexyl hexanoate as a plasticizer, which is less harmful to the human body and eco-friendly, a variable focus lens with excellent performance can be realized.

[0002] The present invention is the result of the local government-university cooperation-based regional innovation project conducted in 2024 with funding from the Ministry of Education and support from the National Research Foundation of Korea (2021RIS-004).

[0003] A variable focus lens refers to a lens that can change its focal length by changing its external shape or internal structure through externally supplied current, voltage, electric field, or magnetic field. Such variable focus lenses can be in a liquid or gel state, and compared to conventional lenses, they can operate with less power and require less space for focus variation, allowing for miniaturization.

[0004] In the process of manufacturing variable focus lenses, plasticizers are used to cure polymer resins. Such plasticizers are required to have a high boiling point, low vapor pressure, and excellent plasticizing ability.

[0005] Meanwhile, restrictions on the use of substances harmful to the environment and the human body, such as endocrine disruptors, have recently been increasing. Furthermore, plasticizers conventionally used in the manufacture of variable focus lenses are also subject to regulation as many contain endocrine disruptors. In particular, phthalate-based plasticizers are known to be easily absorbed into the human body and release endocrine disruptors that interfere with the endocrine system.

[0006] Korean Published Patent No. 10-2018-0114382, a prior art document, discloses a variable focus lens capable of independently controlling the focal lengths of both sides by applying a transparent polymer resin and a plasticizer.

[0007] The present invention aims to provide a lens composition comprising an eco-friendly plasticizer and a method for manufacturing a lens using the same.

[0008] The present invention can reduce harmfulness to the environment and the human body.

[0009] In addition, the present invention can provide a lens with excellent variable characteristics and low leakage current.

[0010] A composition for a variable focus lens according to an embodiment of the present invention comprises a polymer resin and a plasticizer.

[0011] The above plasticizer is a cyclohexane-based plasticizer having a single chain, and the cyclohexane-based plasticizer having a single chain is Cyclohexyl butyrate or Cyclohexyl hexanoate.

[0012] The weight ratio of the polymer resin and plasticizer may be 1:11 to 1:12.5.

[0013] The above polymer resin may be polyvinyl chloride (PVC).

[0014]

[0015] A method for manufacturing a variable focus lens according to an embodiment of the present invention comprises the steps of: preparing a mixed solution by mixing a polymer resin and a plasticizer in a solvent; and removing the solvent from the mixed solution. One embodiment may further include the step of introducing the mixed solution into a lens mold after the step of preparing the mixed solution.

[0016] The above plasticizer is a cyclohexane-based plasticizer having a single chain, and the cyclohexane-based plasticizer having a single chain is Cyclohexyl butyrate or Cyclohexyl hexanoate.

[0017] The weight ratio of the polymer resin and plasticizer may be 1:11 to 1:12.5.

[0018] The above polymer resin may be polyvinyl chloride (PVC).

[0019] The above solvent may be any one of dioxane, tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and 1-methyl-2-pyrrolidone (NMP).

[0020]

[0021] A variable focus lens according to an embodiment of the present invention is manufactured by the method described above.

[0022] The lens composition according to the embodiment of the present invention and the method for manufacturing a lens using the same are environmentally friendly.

[0023] The present invention can reduce harmfulness to the environment and the human body.

[0024] In addition, the present invention can provide a lens with excellent variable characteristics and low leakage current.

[0025] FIG. 1 is a conceptual diagram of a method for manufacturing a variable focus lens according to an embodiment of the present invention.

[0026] FIG. 2 illustrates the operation of a variable focus lens according to an embodiment of the present invention.

[0027] Figure 3 shows the FTIR measurement results of a variable focus lens using cyclohexyl butyrate as a plasticizer.

[0028] Figure 4 shows the FTIR measurement results of a variable focus lens using cyclohexyl hexanoate as a plasticizer.

[0029] Figure 5 shows the light transmittance measurement results of a variable focus lens using cyclohexyl butyrate as a plasticizer.

[0030] Figure 6 shows the light transmittance measurement results of a variable focus lens using cyclohexyl hexanoate as a plasticizer.

[0031] Figure 7 shows the results of measuring the dielectric constant of a variable focus lens using cyclohexyl butyrate as a plasticizer.

[0032] Figure 8 shows the results of measuring the dielectric constant of a variable focus lens using cyclohexyl hexanoate as a plasticizer.

[0033] Figure 9 shows the results of measuring the leakage current of a variable focus lens using cyclohexyl butyrate as a plasticizer.

[0034] Figure 10 shows the results of measuring the leakage current of a variable focus lens using cyclohexyl hexanoate as a plasticizer.

[0035] Figure 11 is a photograph of a comparative example in which 13 parts by weight of the plasticizer cyclohexyl butyrate was added to the polymer resin.

[0036] The drawing symbols are as follows.

[0037] 100: Variable focus lens device, 110: Variable focus lens, 120: Upper substrate, 130: Lower substrate

[0038] Hereinafter, preferred embodiments of the present invention are described as follows with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0039]

[0040] Composition for variable focus lenses

[0041] A composition for a variable focus lens according to an embodiment of the present invention comprises a polymer resin and a plasticizer.

[0042]

[0043] The above polymer resin is a polymer material having transparency and flexibility, and performs the function of maintaining the shape of the lens and refracting incident wavelengths. The above polymer resin may be at least one of PVC (Poly vinyl chloride), PC (Polycarbonate), PET (Polyethylene Terephthalate), and TAC (Triacetate Cellulose), and preferably may be PVC, which has permeability and is easy to process. The molecular weight of the above polymer resin may be 150,000 or more, taking into account flexibility, etc.

[0044] The above PVC can be represented by the following chemical structure formula 1.

[0045] [Chemical Structure Formula 1]

[0046]

[0047] (n is a natural number)

[0048]

[0049] The above plasticizer performs the function of curing the polymer resin to convert it into a gel state. Through this, the plasticizer can reduce leakage current. In an embodiment of the present invention, the plasticizer is a cyclohexane-based plasticizer having a single chain, specifically Cyclohexyl butyrate or Cyclohexyl hexanoate. The Cyclohexyl butyrate and Cyclohexyl hexanoate may be prepared by reacting Cyclohexanol with Carboxylic acid. When Cyclohexanol and Carboxylic acid are reacted, an ester and water are produced, and Cyclohexyl butyrate or Cyclohexyl hexanoate can be obtained by removing the water.

[0050] The above Cyclohexyl butyrate and Cyclohexyl hexanoate can be represented by chemical structural formulas 2 and 3, respectively.

[0051] [Chemical Structure Formula 2]

[0052]

[0053] [Chemical Structure Formula 3]

[0054]

[0055]

[0056] The weight ratio of the polymer resin and the plasticizer may be 1:11 to 1:12.5, preferably 1:11.5 to 1:12.5. If the content of the plasticizer is too high, leakage occurs, and the gel is not transparent, making it impossible to use as a lens. Conversely, if the content of the plasticizer is too low, there is a problem with a low dielectric constant and high leakage current.

[0057]

[0058] Variable focus lens device

[0059] A lens device (100) according to an embodiment of the present invention includes a variable focus lens (110) comprising the lens composition described above. Referring to FIG. 2, the variable focus lens device (100) may include a variable focus lens (110) manufactured by including the lens composition, and an upper substrate (120) and a lower substrate (130) disposed on the upper and lower portions of the variable focus lens (110). The upper substrate (120) or the lower substrate (130) may include a hollow portion in which the curved surface of the lens (110) is disposed, and may include an electrode that contacts the lens (110) to allow current to flow. The upper substrate (120) and the lower substrate (130) may be made of a polymer resin. When current is applied through the electrodes of the upper substrate (120) and the lower substrate (130), the shape of the lens of the variable focus lens (110) is deformed, thereby allowing the focus to be adjusted ( FIG. 2(b)).

[0060]

[0061] Method for manufacturing a variable focus lens

[0062] A method for manufacturing a variable focus lens according to an embodiment of the present invention comprises the steps of: preparing a mixed solution by mixing a polymer resin and a plasticizer in a solvent; and removing the solvent from the mixed solution. One embodiment may further include the step of introducing the mixed solution into a lens mold after the step of preparing the mixed solution.

[0063]

[0064] In the step of preparing the above mixed solution, the solvent may be a polar organic solvent. This is to easily dissolve the transparent polymer resin and P(VC-VA). The polar organic solvent may be any one of dioxane, tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and 1-methyl-2-pyrrolidone (NMP).

[0065]

[0066] The above polymer resin is the one described above in the lens composition. The above polymer resin may be at least one of PVC (Poly vinyl chloride), PC (Polycarbonate), PET (Polyethylene Terephthalate), and TAC (Triacetate Cellulose), and preferably may be PVC, which is permeable and easy to process.

[0067]

[0068] The above plasticizer is the one described above in the lens composition. In an embodiment of the present invention, the plasticizer is a cyclohexane-based plasticizer having a single chain, and specifically may be cyclohexyl butyrate or cyclohexyl hexanoate.

[0069]

[0070] The weight ratio of the polymer resin and plasticizer added in the step of preparing the above mixed solution may be 1:11 to 1:12.5.

[0071]

[0072] The step of preparing the above mixed solution may include the step of preparing a solvent and the step of mixing the polymer resin and the plasticizer. Additionally, the step of dissolving the polymer resin in the solvent may be performed first before adding the plasticizer, and the plasticizer may be added prior to the polymer resin. The mixing step may include the step of stirring the mixed solution containing the polymer resin and the plasticizer in a stirrer. This step may be performed under appropriate conditions to ensure that the polymer resin and the plasticizer dissolve in the solvent, and may be performed at room temperature.

[0073]

[0074] The step of removing the solvent from the above mixed solution may include a step of drying at room temperature and a step of processing in a vacuum oven. The step of drying at room temperature may be performed for 2 to 5 days, and then the remaining solvent may be removed by placing the mixed solution with reduced solvent into a vacuum oven and processing it at room temperature for 12 to 48 hours.

[0075]

[0076] After the step of preparing the above-mentioned mixed solution, the step of introducing the above-mentioned mixed solution into a lens mold may be further included. This step is a step for controlling the thickness and shape of the variable focus lens. This step may also be performed during the step of removing the solvent from the mixed solution. After the solvent of the mixed solution has been removed to a certain extent and the mixed solution has reached a state with an appropriate viscosity, it may be introduced into the lens mold and the remaining solvent may be removed. This allows for easier control of the shape of the variable focus lens and enables the manufacture of a superior surface condition. Next, an upper substrate and a lower substrate may be placed on the upper and lower parts of the lens, respectively. The upper substrate and the lower substrate are the same as those described above.

[0077]

[0078] Example: Manufacture of a variable focus lens

[0079] Example 1 (CHB3): THF (Daejeong, 99.9%) as a solvent, PVC powder (Scientific Polymer Products, Inc., Mw 275,000, CAS: 9002-86-2), and cyclohexyl butyrate prepared by reacting cyclohexanol and carboxylic acid as plasticizers were prepared. 1 g of PVC powder was mixed with 10 ml of THF solvent and completely dissolved. Next, 3 g of the plasticizer, cyclohexyl butyrate, was mixed into the solvent containing the dissolved PVC powder, and stirred with a stirrer at 500 rpm for 4 hours. Then, the mixture was poured into a glass dish and stored for 3 days under conditions of less than 40% relative humidity and room temperature to remove the solvent. A lens was manufactured by placing the gelled mixture into a vacuum oven and processing it for 24 hours to remove the solvent. The thickness of the manufactured lens was 1 mm.

[0080]

[0081] Example 2 (CHB6): Prepared in the same manner as Example 1, except that 6g of the plasticizer Cyclohexyl butyrate was added.

[0082]

[0083] Example 3 (CHB9): Prepared in the same manner as Example 1, except that 9g of the plasticizer Cyclohexyl butyrate was added.

[0084]

[0085] Example 4 (CHB12): Prepared in the same manner as Example 1, except that 12g of the plasticizer Cyclohexyl butyrate was added.

[0086]

[0087] Example 5 (CHB13): Prepared in the same manner as Example 1, except that 13g of the plasticizer Cyclohexyl butyrate was added.

[0088]

[0089] Example 6 (CHH3): Prepared in the same manner as Example 1, except that Cyclohexyl hexanoate was used instead of Cyclohexyl butyrate as a plasticizer and 3g of it was added.

[0090]

[0091] Example 7 (CHH6): Prepared in the same manner as Example 6, except that 6g of the plasticizer Cyclohexyl hexanoate was added.

[0092]

[0093] Example 8 (CHH9): Prepared in the same manner as Example 6, except that 9g of the plasticizer Cyclohexyl hexanoate was added.

[0094]

[0095] Example 9 (CHH12): Prepared in the same manner as Example 6, except that 12g of the plasticizer Cyclohexyl hexanoate was added.

[0096]

[0097] In the case of Example 5, where 13 parts by weight of cyclohexyl butyrate were added to the PVC powder, leakage occurred and the experiment was not conducted (see Fig. 11).

[0098]

[0099] Experimental Example: FTIR Measurement

[0100] The absorbances of the examples and comparative examples, cyclohexyl butyrate, and cyclohexyl hexanoate were measured using an FTIR spectrometer. Figure 3 shows the results when cyclohexyl butyrate was used as a plasticizer, and Figure 4 shows the results when cyclohexyl hexanoate was used as a plasticizer. Referring to Figures 3 and 4, it can be seen that the peak shifts due to hydrogen bonding between the carbonyl peak (C=O) of the plasticizer and the alpha hydrogen of PVC (hydrogen bonded to a carbon directly bonded to a functional group).

[0101]

[0102] Experimental Example: Light Transmittance Analysis

[0103] The light transmittance of the examples and comparative examples was measured using a UV-vis spectrophotometer (HP 8452, HP, USA). Figure 5 shows the results using Cyclohexyl butyrate as a plasticizer, and Figure 6 shows the results using Cyclohexyl hexanoate as a plasticizer. Referring to Figures 5 and 6, it can be seen that Example 4 (CHB12) and Example 9 (CHH12) exhibit excellent light transmittance.

[0104]

[0105] Experimental Example: Measurement of Dielectric Constant

[0106] The dielectric constant was measured by applying a voltage of 2V to the examples and comparative examples in the frequency range from 106Hz to 1Hz. Figure 7 shows the results using Cyclohexyl butyrate as a plasticizer, and Figure 8 shows the results using Cyclohexyl hexanoate as a plasticizer. Referring to Figures 7 and 8, it can be seen that the dielectric constant is high in Example 4 (CHB12) and Example 9 (CHH12), and that Example 4 (CHB12) is superior to Example 9 (CHH12).

[0107]

[0108] Experimental Example: Leakage Current Measurement

[0109] The leakage current of the examples and comparative examples was measured using a potentiostat / galvanostat (Biologic Science Instruments, SP300) in an applied electric field of 400 V / mm at room temperature. Figure 9 shows the results for using Cyclohexyl butyrate as a plasticizer, and Figure 10 shows the results for using Cyclohexyl hexanoate as a plasticizer. Referring to Figures 9 and 10, it can be seen that the leakage current is highest in Example 4 (CHB12) and Example 9 (CHH12).

[0110]

[0111] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, without departing from the technical spirit of the invention, and such are also to be considered to fall within the scope of the present invention.

[0112]

[0113]

Claims

1. Polymer resin and Contains plasticizers, The above plasticizer is a cyclohexane-based plasticizer having a single chain, Composition for variable focus lenses.

2. In Paragraph 1, The above-mentioned cyclohexane-based plasticizer having a single chain is Cyclohexyl butyrate or Cyclohexyl hexanoate, Composition for variable focus lenses.

3. In Paragraph 1, The weight ratio of the polymer resin and plasticizer is 1:11 to 1:12.5, Composition for variable focus lenses.

4. In Paragraph 1, The above polymer resin is Poly vinyl chloride (PVC), Composition for variable focus lenses.

5. A step of preparing a mixed solution by mixing a polymer resin and a plasticizer in a solvent, and The method includes the step of removing the solvent of the above-mentioned mixed solution; The above plasticizer is a cyclohexane-based plasticizer having a single chain, Method for manufacturing a variable focus lens.

6. In Paragraph 5, The above-mentioned cyclohexane-based plasticizer having a single chain is Cyclohexyl butyrate or Cyclohexyl hexanoate, Method for manufacturing a variable focus lens.

7. In Paragraph 5, The weight ratio of the polymer resin and plasticizer is 1:11 to 1:12.5, Method for manufacturing a variable focus lens.

8. In Paragraph 5, The above polymer resin is Poly vinyl chloride (PVC), Method for manufacturing a variable focus lens.

9. In Paragraph 5, The above solvent is any one of dioxane, tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and 1-methyl-2-pyrrolidone (NMP), Method for manufacturing a variable focus lens.

10. In Paragraph 5, After the step of preparing the above mixed solution, A method further comprising the step of introducing the above-mentioned mixed solution into a lens mold. Method for manufacturing a variable focus lens.

11. A variable focus lens manufactured by the method of paragraph 5.

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