Voice coil motor, detergent composition for voice coil motor, and method for washing voice coil motor

Abstract

To provide a voice coil motor (VCM) equipped with a damper material, and to provide the VCM equipped with the damper material cleaned by cleaning the VCM after the damper material is mounted on the VCM.SOLUTION: A VCM provided with a damper material is cleaned by using a detergent composition comprising a nonaqueous organic solvent containing a compound having a solubility parameter of <6 which does not attack the damper material by erosion, dissolution, etc., and does not damage the damper material.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a voice coil motor equipped with a damper material, and more particularly to a voice coil motor that has been cleaned after the damper material has been attached to the voice coil motor. [Background technology]

[0002] A voice coil motor (VCM) is a component built into CMOS camera modules in smartphones and other electronic devices for autofocus and image stabilization functions. The VCM is a component that receives vibrations such as impacts when the lens of the CMOS camera module moves or stops, and is equipped with an elastic vibration absorbing material (damper material) to prevent damage from such impacts. In recent years, the moving parts of VCMs have become faster, and in response to this, efforts have been made to further improve the shock absorption capacity of the damper material attached to VCMs so that damage can be prevented even when parts moving at higher speeds are stopped.In addition, in response to the demand for even higher precision in electronic devices, VCM damper materials are being required to quickly suppress slight vibrations generated inside and outside the electronic device and shocks to the servo function (position control), and to speed up response by even 0.1 seconds.

[0003] As such, the damper material in VCM products is an extremely important component that affects the performance of the VCM product. The damper material is composed of various elastic bodies (for example, Patent Documents 2 to 4), but it has also been recognized that improving the shock absorption capacity makes it more susceptible to damage by chemicals (i.e., reducing chemical resistance). Because of their low chemical resistance, cleaning VCM products equipped with damper materials with water or water-based solvents has been considered, but this poses a significant practical problem due to the inherent risk of corrosion of CMOS camera modules and the like. Therefore, cleaning of VCM products equipped with damper materials has been limited to air cleaning (Patent Document 1), and VCM products equipped with damper materials have been considered uncleanable. Therefore, even if foreign matter adheres to VCM products during the module assembly process with the damper material, the products have been shipped as is.

[0004] If such foreign particles remain on a CMOS camera module, spots caused by the particles will appear in images captured using the CMOS camera module. As such, foreign particles that are generated or adhere to VCM products during the assembly process can reduce the quality of VCM products or cause problems. With the current increasing demand for high-resolution CMOS camera modules, the adhesion of even small particles that were not a problem before is becoming a problem. In order to provide a VCM product with higher cleanliness and higher quality, it is highly desirable to clean the entire VCM product after the damper material is installed in the VCM product. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-167434 [Patent Document 2] Japanese Patent Application Publication No. 57-138041 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-95951 [Patent Document 4] International Publication No. 2017 / 138041 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention was made in consideration of the above-mentioned problems, and aims to clean VCM products equipped with damper material without causing problems such as peeling of the damper material or damage to the VCM structure. That is, the present invention develops a new cleaning agent composition made of a non-aqueous organic solvent that does not damage the damper material used in VCM products, and provides VCM products equipped with damper material that have been cleaned with a cleaning agent made of a non-aqueous organic solvent. [Means for solving the problem]

[0007] That is, the present invention is characterized by the following points. [1] A voice coil motor equipped with a damper material, which has been cleaned with a cleaning composition containing a non-aqueous organic solvent after the damper material is attached to the voice coil motor. [2] A voice coil motor equipped with the damper material according to [1], wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6. [3] A voice coil motor equipped with the damper material described in [1], wherein the damper material is made of one or more materials selected from rubber-based elastomers, silicone-based elastomers, epoxy-based elastomers, acrylic-based elastomers, and polytetrafluoroethylene. [4] A cleaning composition for a voice coil motor after a damper material is attached, the cleaning composition comprising a non-aqueous organic solvent. [5] The cleaning composition according to [4], wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6. [6] The cleaning composition according to [4], wherein the cleaning composition comprising a non-aqueous organic solvent has a solubility parameter of less than 6. [7] The cleaning composition according to [4], wherein the cleaning composition comprising a non-aqueous organic solvent contains tetradecafluoroheptene and / or decafluoro-2-pentene. [8] A method for cleaning a voice coil motor equipped with a damper material, the method using a cleaning agent composition containing a non-aqueous organic solvent. [9] The cleaning method according to [8], wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6.

[10] The cleaning method according to [9], further comprising ultrasonic cleaning. [Effects of the Invention]

[0008] According to the present invention, it is possible to clean the entire VCM product, even if the VCM product has damper material attached. Cleaning according to the present invention does not damage the VCM product or the damper material attached to the VCM product. According to the present invention, it is possible to clean VCM products equipped with damper material while preventing product defects such as peeling of the damper material and damage to the internal structure of the VCM product. The present invention also provides a cleaning composition for VCM after damper material has been installed, and a cleaning method using the cleaning composition. Unlike aqueous cleaners, the cleaning composition of this invention, which is made from a non-aqueous organic solvent, does not corrode VCM products. Furthermore, by using this cleaning composition, it is possible to remove foreign matter that has adhered to VCM products equipped with damper material and cannot be cleaned with air or pure water. [Brief explanation of the drawings]

[0009] [Figure 1] This is a schematic diagram of the camera module. (Source: Alps Alpine Co., Ltd. website, https: / / tech.alpsalpine.com / j / technology-info / actuation / ) [Figure 2] This is a schematic diagram of a camera module including damper material. (Source: Nikkei Crosstech, https: / / xtech.nikkei.com / dm / atcl / column / 15 / 387120 / 121500047 / ) [Figure 3] 1 is a graph showing the removal rate of foreign matter by a cleaning composition comprising a non-aqueous organic solvent of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] Fig. 1 is a schematic diagram of a camera module, and Fig. 2 is a schematic diagram (schematic cross-sectional view) of a camera module (voice coil motor) including a damper material. In Fig. 2, the member that contacts the spring and the housing located on the lower side is the damper material. The VCM equipped with the damper material of the present invention is a VCM equipped with a damper material that has been cleaned using a cleaning composition containing a non-aqueous organic solvent after the damper material has been attached to the VCM.

[0012] The damper material used in the present invention is not limited to any material as long as it can be used as a shock absorbing material, but it is preferable that the damper material be made of one or more materials selected from rubber-based elastomers, silicone-based elastomers such as UV-curable silicone-based resins, epoxy-based elastomers such as thermosetting epoxy resins and two-component mixed curable epoxy resins, acrylic-based elastomers such as UV-curable acrylic resins, room temperature curable silyl group-terminated polymer-based resins, and polytetrafluoroethylene (PTFE). The damper material is generally a gel-like elastic body.

[0013] The cleaning composition comprising a non-aqueous organic solvent used to obtain the VCM equipped with the damper material of the present invention preferably contains a compound with a solubility parameter (SP value) of less than 6. The cleaning composition can use a compound having an SP value of less than 6 either alone or in combination. Alternatively, a compound having an SP value of less than 6 can be mixed with a compound having an SP value of 6 or greater so that the cleaning composition has an SP value of less than 6.

[0014] Here, the SP value is a known parameter proposed by Hildebrand et al. (see, for example, the Journal of the Adhesion Society of Japan (Vol. 53, No. 4, 129) described below), and is defined by the following mathematical formula:

[0015] δ=(E / V) 1 / 2 where δ is the SP value, E is the energy of vaporization, and V is the molar volume.

[0016] Compounds with an SP value of less than 6 have no affinity with the constituent materials of damper materials, so the cleaning composition of this invention, which is made of a non-aqueous organic solvent and contains a compound with an SP value of less than 6, will not peel off the damper materials attached to VCM products or cause changes in the surface condition of the damper materials. Also, unlike water or water-based cleaning agents, it will not cause corrosion problems in VCM products.

[0017] Examples of compounds with an SP value of less than 6 include olefin compounds that may contain heteroatoms such as N and S in the structure but contain as few hydrogen atoms as possible. For example, Tetradecafluoroheptene (SP value 5.9), Decafluoro-2-pentene (SP value 5.8), (2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene (SP value 5.9) Examples include:

[0018] The cleaning agent of the present invention, which is made of a non-aqueous organic solvent, has a global warming potential (GWP) of 1 A compound having a valence of less than 0 is preferred from the viewpoint of protecting the global environment. By cleaning with the cleaning composition containing a non-aqueous organic solvent of the present invention, the removal rate of fine particles of 5 μm or more on VCM products equipped with damper material is 60% compared to before cleaning. Examples of particles that may be attached to a VCM product equipped with damper material before cleaning include inorganic particles (such as metal particles derived from the components that make up the VCM) and organic particles (such as polymer particles derived from the components that make up the damper material).These particles are generated and attached during the assembly of the damper material into the VCM product. If these fine particles remain attached to the VCM product and are incorporated into various products, they can cause problems or reduce the quality of the VCM product or the product into which the VCM product is incorporated, which is undesirable. In the method for cleaning a VCM product equipped with a damper material of the present invention, it is preferable to use the above-mentioned cleaning agent composition comprising a non-aqueous organic solvent. There is no specific limitation on the cleaning method, but it is more preferable to perform cleaning in combination with an ultrasonic cleaning step. [Example]

[0019] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0020] (SP value of cleaning agent) The SP value of the cleaning agent was calculated using the following formula:

[0021] δ=(E / V) 1 / 2 where δ is the SP value, E is the evaporation energy, and V is the molar volume. The results are shown in Table 1.

[0022] (Damper material constituent materials) Bisphenol-type liquid epoxy resin (Two-component elastic adhesive, ThreeBond Fine Chemical Co., Ltd., ThreeBond (registered trademark) 3950D, SP value 10.9)

[0023] (cleaning agent) The detergent compositions used in the examples and comparative examples consisted of the following: Tetradecafluoroheptene (Opteon (registered trademark) SF70 manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd.; Examples) Decafluoro-2-pentene (PFP ​​manufactured by Mitsui Chemours Fluoroproducts Co., Ltd.; in the examples) (2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene (F13iE manufactured by Chemours Inc.; Example) Tetradecafluorohexane (3M Japan Ltd., PF-5060; comparative example) 1,1,1,4,4,4-hexafluoro-2-butene (Z) (Opteon (registered trademark) SF33 manufactured by Chemours Inc.; comparative example) Nonafluorobutyl methyl ether (Novec® 7100 manufactured by 3M Japan Ltd.; comparative example) 1,1,1,2,2,3,4,5,5,5-decafluoropentane (Vertrel (registered trademark) XF manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd.; comparative example)

[0024] [Examples 1 to 3, Comparative Examples 1 to 4] (Effects of cleaning on damper materials) In Examples 1 to 3 and Comparative Examples 1 to 4, cleaning was carried out in accordance with the following steps. <1> 50 ml of the detergent composition was placed in a 250 ml glass bottle. <2> 0.05 g of the constituent material of the damper material was taken up in a dropper, dropped onto the slide glass, and after hardening, placed in the glass bottle. <3> The glass bottle was immersed in a tabletop ultrasonic cleaner (As One Corporation, ultrasonic cleaner VS-100III) filled with water and irradiated with ultrasonic waves at 100 kHz, 100 W, and room temperature for 5 minutes. (Note that the boiling point of decafluoro-2-pentene is approximately 22°C, so in this case only, the temperature was 17°C.) Furthermore, evaluation after washing in Examples 1 to 3 and Comparative Examples 1 to 4 was carried out by the following methods. <1> The slide glass used for the test was taken out of the glass bottle, and the surface condition was visually observed. <2> The rate of change in weight (rate of weight increase or decrease) was calculated from the weights of the constituent materials of the damper material before and after the test. The results are shown in Table 1.

[0025] [Table 1]

[0026] The weight gain / loss rate of the resin component that makes up the damper material before and after cleaning was 1.0% or less in Examples 1 to 3 and Comparative Example 1, which used the cleaning composition made of a non-aqueous organic solvent of the present invention. These results confirmed that cleaning a VCM product equipped with a damper material with the cleaning composition made of a non-aqueous organic solvent of the present invention does not affect the damper material. The cleaning composition made of a non-aqueous organic solvent in Comparative Example 1 does not affect the damper material, just like Examples 1 to 3, but because it has a high global warming potential (GWP), it is considered a comparative example. The cleaning compositions made of non-aqueous organic solvents used in Comparative Examples 2 to 4 caused a large change in the weight gain / loss rate of the resin components that make up the damper material before and after cleaning. It was confirmed that cleaning VCM products equipped with damper material with such cleaning compositions had a significant effect on the damper material.

[0027] [Example 4] (Removal of fine particles by cleaning) In Example 4, a cleaning test was conducted using the cleaning composition of Example 1 (Opteon (registered trademark) SF70) to confirm the effect of the cleaning composition in removing fine particles from a silicon wafer made of silicone resin, which is the material of the damper material. The experimental method is as follows. <1> 1 g of PTFE powder (Zonyl PTFE MP-1100, manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd.) was placed in a bottle and dispersed in 100 ml of isopropyl alcohol (IPA). The mixture was gently shaken and allowed to stand overnight, and 2 ml of the supernatant liquid was then sucked up with a dropper. <2> A 6-inch silicon wafer was placed on a spin coater (POLOS-SPIN150 (SPS-Europe)) and rotated at 2000 rpm. <1> 2 ml of the supernatant was added dropwise. <3> After the dropping was completed, the rotation was continued for another 35 seconds to shake off the IPA. <4> <3> The particles on the wafer surface were measured using a particle measuring device (YPI-MN, manufactured by Yamanashi Technical Workshop Co., Ltd.). <5> Using a two-tank vapor degreaser (YMPT SK-14Y-1617), <4> The silicon wafer whose particles were measured in the above was immersed in cleaning tank 1 filled with Opteon (registered trademark) SF70 and irradiated with ultrasonic waves at 120 kHz at 50°C for 120 seconds, and then immersed again in cleaning tank 2, which was different from cleaning tank 1 and also filled with Opteon (registered trademark) SF70, and irradiated with ultrasonic waves at 120 kHz at 50°C for 105 seconds. <6> <5> Particles on the wafer surface of <4> The measurement was carried out using the same particle measuring device as in Example 1. <7> The number of particles on the silicon wafer before and after cleaning was directly measured, and the particle removal rate was calculated by comparing these results. Particle removal rate = Number of particles on wafer after cleaning / Number of particles on wafer before cleaning

[0028] The results are shown in Figure 3. Polytetrafluoroethylene is a substance widely used as a damper material, and it was confirmed that cleaning with a cleaning composition containing Opteon (registered trademark) SF70 removed nearly 80% of even minute foreign particles as small as 10 μm on silicon wafers, and even for even smaller particles as small as 5 μm, it removed about 60%. Furthermore, even when the cleaning agent compositions comprising non-aqueous organic solvents of Examples 2 and 3 and Comparative Example 1 were used instead of Opteon (registered trademark) SF70, the same tendency was observed.

[0029] As shown in Figure 2, VCM has a complex surface shape. Therefore, it is impossible to accurately measure the removal rate of contaminants on VCM products equipped with damper materials by a cleaning composition by directly observing the VCM surface. Therefore, the experimental system used in Example 4 to confirm the removal rate of contaminants on silicon wafers was adopted, and this method is an established method for confirming the removal rate by cleaning. If the evaluation in Example 4 proves effective, the damper material will be installed on the VCM of the VCM product. It can be evaluated that the method is similarly effective in removing foreign matter.

Claims

1. A voice coil motor equipped with a damper material, the voice coil motor being cleaned with a cleaning agent composition comprising a non-aqueous organic solvent after the damper material is attached to the voice coil motor.

2. 2. A voice coil motor equipped with a damper material according to claim 1, wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6.

3. 2. A voice coil motor equipped with a damper material according to claim 1, wherein the damper material is made of one or more materials selected from the group consisting of rubber-based elastomers, silicone-based elastomers, epoxy-based elastomers, acrylic-based elastomers, and polytetrafluoroethylene.

4. A cleaning composition for a voice coil motor after a damper material has been installed, the cleaning composition comprising a non-aqueous organic solvent.

5. The cleaning composition according to claim 4, wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6.

6. 5. The cleaning composition according to claim 4, wherein the cleaning composition comprising a non-aqueous organic solvent has a solubility parameter of less than 6.

7. 5. The cleaning composition according to claim 4, wherein the cleaning composition comprising a non-aqueous organic solvent contains tetradecafluoroheptene and / or decafluoro-2-pentene.

8. A method for cleaning a voice coil motor equipped with a damper material, the method using a cleaning agent composition containing a non-aqueous organic solvent.

9. The cleaning method according to claim 8, wherein the cleaning composition comprising a non-aqueous organic solvent contains a compound having a solubility parameter of less than 6.

10. The cleaning method of claim 9 further comprising ultrasonic cleaning.

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