JP2011189243A - Dust remover, and method of removing dust using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dust remover capable of surely collecting and removing dust sticking to an uneven surface of an object from which dust is to be removed, such as a surface of a microlens, and of preventing the transfer of a resin or other components to the uneven surface; and a method of removing dust using the same. <P>SOLUTION: The dust remover 1 includes a hot-melt layer 3 formed on the surface of a plastic film 2 or a support, and removes dust sticking to an uneven surface 11 of an object from which dust is to be removed, by causing the hot-melt layer 3 to contact the uneven surface 11 by thermocompression and subsequently allowing it to cool. The hot-melt layer 3 is formed of a thermoplastic-resin layer comprising a thermoplastic resin of a softening point in a range of 110 to 170°C or a plurality of thermoplastic resins each having a mutually different softening point. Upon removing dust, the hot-melt layer 3 of the dust remover 1 is made to contact the uneven surface 11 by thermocompression at a temperature not higher than the softening point of the thermoplastic resin, and is subsequently cooled, and the dust remover 1 is peeled off from the uneven surface 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dust removing material for removing dust adhering to an uneven surface such as a microlens surface and a dust removing method using the same.

  In a solid-state image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), a condensing microlens is generally formed on the surface of the solid-state image sensor for the purpose of improving sensitivity. In this case, dust (dust) such as metal powder, organic matter, or fiber may adhere to the surface of the microlens for some reason. Dust adheres in such a way that it enters an uneven portion (uneven surface) on the surface of the microlens. For this reason, it becomes a big subject to remove reliably the dust adhering to the surface of a micro lens.

  As a method of removing dust on a fine uneven surface, for example, (1) a resin in which dust is trapped after applying a resin dissolved in a solvent on the uneven surface to which dust is attached, evaporating the solvent (2) A method of attaching a fine adhesive sheet or the like to an uneven surface to which dust is attached, and a method of capturing and removing dust from the adhesive layer. (3) An ultraviolet curable resin is applied to the uneven surface to which dust is attached. A method of removing UV-cured resin that has captured dust after coating and UV-curing, and (4) a method of pressure-bonding elastic rubber to the uneven surface to which dust has adhered and capturing and removing dust on the surface of elastic rubber are considered. It is done.

  However, the methods (1) to (3) have a problem in that when the resin (adhesive) is removed, the resin is transferred to the uneven surface, which becomes dust. Specifically, in the methods (1) and (3), since the coating film strength of the resin is weak, the resin is easily cut when the resin is removed, and the resin is likely to remain in the uneven gap. Further, in the method (2), since many low molecular weight components such as monomers and plasticizers are used for the pressure-sensitive adhesive, the low molecular weight components adhere to the surface, and when the pressure-sensitive adhesive sheet is removed, the low molecular weight components are formed on the uneven surface. It becomes easy to remain. Further, the method (2) has a problem that when the fine adhesive sheet is attached to the microlens, the followability to the uneven surface is poor, and the dust that has entered the uneven space cannot be captured. Further, the method (3) has a problem that a component (uncured component) that cannot be cured by ultraviolet irradiation adheres to the uneven surface. This is because in the case of an ultraviolet curable resin, not all the resin components are polymerized, and not a few uncured components remain. In the method (4), there is a problem that components such as a plasticizer bleed and adhere. Moreover, since elastic rubber has a certain amount of hardness, it is difficult to follow an uneven surface.

  For example, Patent Document 1 discloses a technique for removing foreign matter on the surface of a semiconductor wafer using an adhesive tape as a technique close to the method (2). This Patent Document 1 describes the use of a thermoplastic pressure-sensitive adhesive, changing the properties of the pressure-sensitive adhesive step by step between application and peeling.

  However, in the technique described in Patent Document 1, there is insufficient study as to what kind of thermoplastic resin should be used as the thermoplastic pressure-sensitive adhesive, eliminating the transfer of the resin to the uneven surface, and the dust. It has not yet been achieved to improve the capture efficiency.

  On the other hand, attempts have been made to avoid adhesion of dust by means of the microlens side. For example, Patent Document 2 discloses that a roughened flattened layer is formed on a microlens using a fluorine-based acrylic resin so as to avoid adhesion of dust and foreign matters. Further, for example, Patent Document 3 discloses a method of manufacturing a solid-state imaging device that improves the cleaning effect during dicing without damaging the microlens by forming a hydrophilic thin film on the surface of the microlens array. Has been.

  However, the formation of a flattening layer or a hydrophilic thin film necessitates a change in the structure of the solid-state image sensor, leading to an increase in manufacturing cost and a decrease in performance of the solid-state image sensor.

JP-A-8-88207 JP 2007-53153 A JP 2007-194307 A

  Thus, the change in the element structure causes an increase in manufacturing cost and a decrease in element performance. For this reason, the development of a dust removal technique that can reliably remove dust and does not cause transfer of resin or the like is expected.

  The present invention has been proposed in view of such conventional circumstances, and can reliably capture and remove dust adhering to an uneven surface such as a microlens surface. It is an object of the present invention to provide a dust removing material that does not transfer any of the components and a dust removing method using the same.

  In order to achieve the above-mentioned object, the dust removing material of the present invention has a hot melt layer formed on the surface of a support, and after the hot melt layer is pressure-bonded to the uneven surface of the dust removing object, it is cooled. A dust removing material for removing dust adhering to the uneven surface, wherein the hot melt layer is a thermoplastic resin composition layer formed of a plurality of thermoplastic resins having different softening temperatures.

  In the dust removing material of the present invention, the hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature, It is a thermoplastic resin composition layer in which the softening temperatures of the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin are in the range of 110 to 170 ° C., respectively.

In the dust removing material of the present invention, the hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature. The low softening temperature thermoplastic resin based on (1) and the high softening temperature thermoplastic resin have an average softening temperature in the range of 110 ° C to 170 ° C.
Formula (1): Average softening temperature (° C.) = WL × TL + WH × TH
WL: Weight ratio of low softening temperature thermoplastic resin WH: Weight ratio of high softening temperature thermoplastic resin TL: Softening temperature of low softening temperature thermoplastic resin TH: Softening temperature of high softening temperature thermoplastic resin

  In order to achieve the above-mentioned object, the dust removing material of the present invention has a hot melt layer formed on the surface of the support, and the hot melt layer is thermocompression bonded to the uneven surface of the dust removing object, and then cooled. A dust removing material for removing dust adhering to the uneven surface, wherein the hot melt layer is formed of a thermoplastic resin having a softening temperature in a range of 110 ° C to 170 ° C. It is a physical layer.

  In order to achieve the above-mentioned object, the dust removal method of the present invention is a dust removal method for removing dust on the uneven surface of a dust removal object using a dust removal material having a hot melt layer formed on the surface of a support. The hot melt layer is formed as a thermoplastic resin composition layer composed of a plurality of thermoplastic resins having different softening temperatures, and the hot melt layer is formed at the uneven surface at a temperature equal to or lower than the softening temperature of the thermoplastic resin. Then, the dust removing material is cooled and then peeled off from the uneven surface.

  In the dust removing method of the present invention, the hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature, A thermoplastic resin composition layer in which the softening temperature of the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin is in the range of 110 to 170 ° C., respectively, at a temperature equal to or lower than the softening temperature of the low softening temperature thermoplastic resin. The hot melt layer is thermocompression-bonded to the uneven surface, cooled, and the dust removing material is peeled from the uneven surface.

In the dust removal method of the present invention, the hot melt layer is made of a thermoplastic resin composed of a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature. As a thermoplastic resin composition layer formed as a resin composition layer, the average softening temperature of the low softening temperature thermoplastic resin based on the formula (1) and the high softening temperature thermoplastic resin is in the range of 110 ° C to 170 ° C. Forming, hot-pressing the hot melt layer on the uneven surface at a temperature lower than the softening temperature of the low-softening temperature thermoplastic resin, cooling, and separating the dust removing material from the uneven surface. .
Formula (1): Average softening temperature (° C.) = WL × TL + WH × TH
WL: Weight ratio of low softening temperature thermoplastic resin WH: Weight ratio of high softening temperature thermoplastic resin TL: Softening temperature of low softening temperature thermoplastic resin TH: Softening temperature of high softening temperature thermoplastic resin

  In the dust removing method of the present invention, a heating temperature at the time of the thermocompression bonding is not less than a glass transition temperature of the low softening temperature thermoplastic resin.

  In the dust removing method of the present invention, the back side of the object to be removed with the uneven surface is supported by a support base, and the dust removing material is pushed onto the uneven surface by a pressing head having at least a tip as an elastic body. The dust removing material is heated and cooled by the support table.

  In the dust removing method of the present invention, the back side of the object to be removed having the uneven surface is supported by a support base, and the dust removing material is pushed onto the uneven surface by a pressing head having at least a tip as an elastic body. The dust removing material is heated and cooled by the pressing head.

  In order to achieve the above-mentioned object, the dust removing method of the present invention removes dust on the uneven surface of a dust removal object having an uneven surface by using a dust removing material having a hot melt layer formed on the surface. A method for removing dust, wherein the hot melt layer is formed as a thermoplastic resin composition layer containing a thermoplastic resin having a softening temperature in a range of 110 to 170 ° C., and a temperature equal to or lower than the softening temperature of the thermoplastic resin. The hot-melt layer of the dust removing material is thermocompression-bonded to the uneven surface, and then cooled, and the dust removing material is peeled off from the uneven surface.

  In the dust removing material of the present invention, dust is captured when the hot melt layer formed on the support is partially melted and softened by thermocompression bonding, and is fixed in the hot melt layer when cured by cooling. . By forming this hot melt layer with a thermoplastic resin composition layer containing a thermoplastic resin and softening it by heat, it becomes possible to follow a micro uneven surface such as a microlens. In addition, a thermoplastic resin has a specific softening temperature according to the kind. In practice, however, the hot melt layer begins to partially melt before the thermoplastic resin reaches the softening temperature. For this reason, by selecting appropriate thermocompression bonding conditions, dust can be captured and transfer of the hot melt layer itself can be suppressed.

  In addition, by forming the hot melt layer with a thermoplastic resin composition layer containing multiple thermoplastic resins with different softening temperatures, the hot melt layer does not proceed with thermal melting and traps dust under a wide range of thermocompression bonding conditions. And transfer of the hot melt layer itself can be further suppressed.

  According to the dust removing material and the dust removing method of the present invention, it is possible to reliably capture and remove dust adhering to an uneven surface such as a microlens surface. Further, the dust removing material itself does not transfer onto the uneven surface, and it is possible to realize highly reliable dust removal.

It is a schematic sectional drawing which shows the structural example of the dust removal material in this Embodiment. It is a figure explaining the dust removal principle by the dust removal material in this Embodiment. (A) is a figure which shows the state before thermocompression bonding, (b) is a figure which shows a thermocompression bonding state, (c) is a figure which shows a dust capture | acquisition state, (d) is the state after peeling. FIG. It is a schematic diagram which shows an example of the dust removal system which performs the dust removal of the workpiece | work surface continuously using a long dust removal material. (A) is a figure which shows the mounting process of the workpiece | work on the heater, (b) is a figure which shows a thermocompression bonding process, (c) is a figure which shows a cooling process, (d) is a peeling process. (E) is a figure which shows the winding-up process of a used dust removal material, (f) is a figure which shows moving a workpiece | work to the next process. It is a schematic diagram which shows the other example of the dust removal system which performs the dust removal of the workpiece | work surface continuously using a long dust removal material. (A) is a figure which shows the mounting process on the support stand of a workpiece | work, (b) is a figure which shows a thermocompression bonding process, (c) is a figure which shows a cooling and peeling process, (d) These are figures which show the winding-up process of a used dust removal material, (e) is a figure which shows moving a workpiece | work to the next process. It is a figure which shows the dynamic viscoelastic property of a hot-melt layer. It is a figure which shows the state of the uneven surface before dust removal, after dust distribution, and after dust removal material peeling.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a dust removing material and a dust removing method to which the present invention is applied (hereinafter referred to as “this embodiment”) will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of the dust removing material in the present embodiment. As shown in FIG. 1, the dust removing material 1 is obtained by forming a hot melt layer 3 by applying a thermoplastic resin to one surface of a plastic film 2 serving as a support. By using the dust removing material 1 having such a configuration, for example, the dust attached to the surface (uneven surface) of a microlens as a dust removing object formed on a solid-state imaging device such as a CCD or CMOS is heated. It is possible to remove dust on the microlens surface at the same time that it is captured by pressure bonding and peeled off after cooling. The dust removal object is not limited to this as long as it has an uneven surface.

  As the plastic film 2, any plastic film that is not softened by heat at the time of thermocompression bonding can be used. For example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polyphenylene sulfide (PPS) film, etc. Can be mentioned. Among these, a PET film is preferable because it does not have a problem such that interfacial peeling of the hot melt layer easily occurs. In addition, the plastic film 2 can have an arbitrary value for thickness, elastic modulus, and the like, and can have a normal thickness and elastic modulus used as a film. Specifically, those having a thickness of about 12 to 100 μm and an elastic modulus of about 1 to 15 GPa · s can be used. For example, the elastic modulus of the PET film is 4 to 6 GPa · s, the elastic modulus of the PEN film is 6 GPa · s, and the elastic modulus of the PPS film is 10 to 13 GPa · s.

  The hot melt layer 3 is a thermoplastic resin composition layer formed of a thermoplastic resin, and heat melting progresses and softens by heating. The hot melt layer 3 captures dust by being softened by heating. And the hot-melt layer 3 hardens | cures by subsequent cooling, and fixes the capture | acquired dust inside.

  The thermoplastic resin of the hot melt layer 3 may be any resin as long as it can soften by heating and trap dust, and can be cured by cooling and fix the trapped dust. Those having a softening temperature of 110 ° C to 170 ° C are preferred, and those having a softening temperature of 120 to 165 ° C are particularly preferred. For example, when PET, PEN, or the like is selected as the plastic film 2, polyester, polyester polyurethane, or the like is preferable as the thermoplastic resin of the hot melt layer 3. When the softening temperature is 110 ° C. or higher, it is possible to prevent the thermoplastic resin from being transferred to the uneven surface of the microlens without melting more than necessary. Further, when the softening temperature is 170 ° C. or lower, sufficient adhesiveness can be obtained during thermocompression bonding and dust can be sufficiently captured.

  When the softening temperature of the thermoplastic resin is less than 110 ° C., the thermoplastic resin constituting the hot melt layer 3 may be transferred to the uneven surface. On the other hand, if the softening temperature of the thermoplastic resin exceeds 170 ° C., sufficient tackiness cannot be obtained during thermocompression bonding, and dust may not be captured sufficiently.

  The hot melt layer 3 may be formed of a plurality of types of thermoplastic resins having different softening temperatures. Thereby, in the hot melt layer 3, the thermal melting does not proceed sharply, that is, the melt viscosity of the hot melt layer 3 does not change sharply. For this reason, while capturing dust under a wide range of thermocompression bonding conditions, it is possible to prevent the thermoplastic resin of the hot melt layer 3 from being transferred to the uneven surface.

  For example, the hot melt layer 3 is a combination of a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high temperature. In this case, the softening temperature of the low softening temperature thermoplastic resin is preferably 110 ° C to 140 ° C. Furthermore, the softening temperature of the low softening temperature thermoplastic resin is particularly preferably 115 to 130 ° C., which is around 120 ° C. The softening temperature of the high softening temperature thermoplastic resin is preferably 140 to 170 ° C. Furthermore, 145-170 degreeC which is 165 degreeC vicinity is preferable.

  Since the softening temperature of the low softening temperature thermoplastic resin is 110 ° C. or higher, the low softening temperature thermoplastic resin does not melt more than necessary, so transfer to the uneven surface after peeling the dust removing material is possible. Can be suppressed. Moreover, when the softening temperature of the high softening temperature thermoplastic resin is 170 ° C. or lower, sufficient adhesiveness can be obtained during thermocompression bonding and dust can be sufficiently captured.

  Also, when the difference between the softening temperature of the low softening temperature thermoplastic resin and the softening temperature of the high softening temperature thermoplastic resin is small, the difference in melt viscosity is also small, so the low softening temperature thermoplastic resin and the high softening temperature heat With plastic resin, it exists in the tendency which shows the behavior accompanied. In particular, when the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin are of the same type (for example, both are polyester resins), this tendency becomes remarkable. As a result of experiments and verification, it was found that the difference between the softening temperature of the low softening temperature thermoplastic resin and the softening temperature of the high softening temperature thermoplastic resin is preferably 30 ° C. or more. For this reason, it is preferable that the softening temperature of a low softening temperature thermoplastic resin is 140 degrees C or less.

  As described above, the softening temperature of the high softening temperature thermoplastic resin is preferably 170 ° C. or lower, and the difference from the softening temperature of the low softening temperature thermoplastic resin is preferably 30 ° C. or higher. For this reason, the softening temperature of the high softening temperature thermoplastic resin is preferably 140 ° C. or higher as described above.

Alternatively, in the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin, the average of the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin calculated by the formula (1) The softening temperature may be in the range of 110 ° C to 170 ° C. The average softening temperature of the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin is in the range of 110 ° C. to 170 ° C., thereby preventing transfer of the hot melt layer 3 to the uneven surface of the thermoplastic resin. At the same time, sufficient adhesiveness can be obtained during thermocompression bonding and dust can be sufficiently captured.
Formula (1): Average softening temperature (° C.) = WL × TL + WH × TH
WL: Weight ratio of low softening temperature thermoplastic resin WH: Weight ratio of high softening temperature thermoplastic resin TL: Softening temperature of low softening temperature thermoplastic resin TH: Softening temperature of high softening temperature thermoplastic resin

  For example, when using three or more kinds of thermoplastic resins having different softening temperatures, as in the case of using two kinds of thermoplastic resins, the three or more kinds of thermoplastic resins are respectively referred to as low softening temperature thermoplastic resins. It can be applied to a high softening temperature thermoplastic resin and considered as described above.

  If the low softening temperature thermoplastic resin is (A) and the high softening temperature thermoplastic resin is (B), the blending ratio (A) / (B) is 1/9 to 9/1. It is particularly preferable that (A) / (B) = 3/7 to 9/1. By setting (A) / (B) = 1/9 to 9/1, the hot melt layer 3 itself can be prevented from being transferred, and dust can be sufficiently captured.

  When PET and PEN are selected as the plastic film 2 as the support, the thermoplastic resin constituting the hot melt layer 3 is preferably a polyester resin or a polyester polyurethane resin, and a polyester resin having an average molecular weight of about 5000 to 50000. Or a polyester polyurethane resin is preferable. As a commercial item, the material suitable for the target property can be selected from UE series (made by Unitika Co., Ltd.) and Byron series (Toyobo Co., Ltd.) appropriately.

  The low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin may be a combination of the same type of resins or a combination of different types of resins. As a combination of the same kind of resins, a combination of polyester resins is particularly preferable. Note that when the low softening temperature thermoplastic resin and the high softening temperature thermoplastic resin are a combination of different types of resins, bleed may occur if the compatibility between the resins is poor.

  Here, the thickness of the hot melt layer 3 can be set according to, for example, the height of the uneven surface of the uneven surface, and can be set to about 5 to 100 μm, for example.

  In addition to the thermoplastic resin, various additives such as a curing agent can be added to the hot melt layer 3. By adding an additive, it is possible to adjust the thermal properties and the like of the hot melt layer 3. However, for example, when a curing agent is added, dust may not be captured if it is added excessively, so it is preferable to add it in an appropriate addition amount range.

  By providing such a configuration, the dust removing material 1 can reliably capture and remove dust attached to the surface (uneven surface) of the microlens. Further, the dust removing material itself does not transfer onto the uneven surface, and it is possible to realize highly reliable dust removal.

  Next, a dust removing method using the dust removing material 1 will be described. FIG. 2 is a diagram for explaining an example of a dust removal process using the dust removing material 1.

  As shown in FIG. 2A, when removing the dust 12 on the uneven surface 11 such as a microlens, first, the hot melt layer 3 of the dust removing material 1 is disposed so as to face the uneven surface 11. In the example shown in FIG. 2, the hot melt layer 3 of the dust removing material 1 contains a low softening temperature thermoplastic resin 3A and a high softening temperature thermoplastic resin 3B. For example, in the case of a microlens, the height of the unevenness of the uneven surface 11 is about 1 μm to 2 μm, but the dust removing material 1 can handle an uneven surface with an unevenness height of about 10 μm.

  Next, as shown in FIG. 2 (b), the dust removing material 1 is placed on the uneven surface 11, and thermocompression bonding is performed between the uneven surface 11 and the dust removing material 1 by heating and pressing. By this thermocompression bonding, the low softening temperature thermoplastic resin 3A of the hot melt layer 3 is partially melted and softened, and the dust 12 is captured. In the thermocompression bonding, heat may be applied to the dust removing material 1 from the back surface side of the uneven surface 11, or heat may be applied from the back surface side of the dust removing material 1.

  When performing thermocompression bonding, it is necessary to appropriately control the heating temperature. For example, if the heating temperature is too high, the hot melt layer 3 is totally melted. As a result, the thermoplastic resin constituting the hot melt layer 3 may be transferred to the uneven surface 11. Further, when the hot melt layer 3 is then cured by returning to normal temperature, it becomes difficult to peel off, and there is a possibility that adhesive residue, damage to the uneven surface 11 or the like may occur. On the other hand, if the heating temperature is too low, sufficient adhesiveness of the thermoplastic resin cannot be obtained, and the dust removing material 1 may not be able to capture dust sufficiently.

  The heating temperature in thermocompression bonding is preferably set to be equal to or lower than the softening temperature of the thermoplastic resin of the hot melt layer 3. The softening temperature is measured by a method based on JIS K2513. Specifically, the temperature at which the flow of the thermoplastic resin can be remarkably confirmed is measured as the softening temperature. However, the thermoplastic resin actually starts to partially melt at a temperature slightly lower than the softening temperature. That is, in the dust removing method according to the present embodiment, focusing on this point, the thermocompression bonding temperature is set to be equal to or lower than the softening temperature of the thermoplastic resin of the hot melt layer 3.

  By setting the heating temperature in the thermocompression bonding to be equal to or lower than the softening temperature of the thermoplastic resin of the hot melt layer 3, the hot melt layer 3 gradually softens without being rapidly progressed. The dust on the surface 11 can be reliably taken inside. Moreover, since it does not fuse | melt entirely below the softening temperature of low softening temperature plastic resin 3A, it can prevent that the thermoplastic resin of the hot-melt layer 3 transfers to the uneven surface 11. FIG. In the example shown in FIG. 2, the heating temperature in thermocompression bonding is preferably set to be equal to or lower than the softening temperature of the low softening temperature thermoplastic resin 3A. As a result, the hot melt layer 3 is gradually softened when the melting of the low softening temperature thermoplastic resin 3A partially starts and does not melt as a whole.

  Moreover, it is preferable that the heating temperature in thermocompression bonding is equal to or higher than the glass transition temperature of the thermoplastic resin of the hot melt layer 3. As described above, the thermoplastic resin has tackiness (dynamic adhesiveness) in the temperature range from the glass transition temperature to the softening temperature. For this reason, by making the heating temperature at the time of thermocompression bonding be equal to or higher than the glass transition temperature of the thermoplastic resin of the hot melt layer 3, the entire thermoplastic resin of the hot melt layer 3 is given adhesion by tackiness, and the dust removing material 1 is provided. Good adhesion to the uneven surface 11 is possible. In addition, when the glass transition temperature of a thermoplastic resin is less than normal temperature (for example, 20 degreeC-30 degreeC), even if it is a time of not heating, the adhesiveness can be given to the hot-melt layer 3 whole.

  Actually, it is preferable to perform the thermocompression bonding at a temperature higher than the glass transition temperature of the thermoplastic resin and lower than or equal to the softening temperature of the thermoplastic resin as much as possible. However, even when the heating temperature at the time of thermocompression bonding is a temperature that is not lower than the glass transition temperature and not higher than the softening temperature and does not increase to the vicinity of the softening temperature, the thermoplastic resin has obtained adhesion due to tackiness. Therefore, by adjusting the pressure value at the time of thermocompression bonding to a value larger than the pressure value at the time of the above-described thermocompression bonding, the hot melt layer 3 can enter the uneven surface 11 and dust can be sufficiently removed. .

  Thereby, the thermoplastic resin has sufficient adhesiveness at the time of thermocompression bonding, and can reliably capture dust. In the example shown in FIG. 2, it is preferable that the heating temperature in thermocompression bonding is equal to or higher than the glass transition temperature of the low softening temperature thermoplastic resin 3A. Thereby, since sufficient adhesiveness of the low softening temperature thermoplastic resin 3A is obtained at the time of thermocompression bonding, the dust removing material 1 can capture dust reliably.

  The thermocompression bonding time in thermocompression bonding is preferably about 5 to 30 seconds, particularly preferably 15 to 30 seconds. If the thermocompression bonding time in thermocompression bonding is too long, the hot melt layer 3 may be melted as a whole. On the other hand, if the thermocompression bonding time in thermocompression bonding is too short, sufficient adhesiveness of the thermoplastic resin cannot be obtained, and the dust removing material 1 may not be able to capture dust sufficiently.

  Next, heating of the dust removing material 1 is stopped, and the hot melt layer 3 is returned to room temperature. At this time, the dust removing material 1 may be cooled. By returning the hot melt layer 3 to room temperature, as shown in FIG. 2C, the hot melt layer 3 is cured with the dust 12 taken in. By controlling the heating temperature and thermocompression bonding time in the previous thermocompression bonding as described above, the hot melt layer 3 is cured in a state in which dust is completely taken into the interior when the temperature is returned to room temperature.

  Thereafter, as shown in FIG. 2 (d), the dust removing material 1 is peeled from the uneven surface 11. Thereby, the dust 12 on the uneven surface 11 is removed from the uneven surface 11. By controlling the heating temperature and the thermocompression bonding time in the previous thermocompression bonding as described above, the dust completely taken into the hot melt layer 3 can be surely removed by peeling. In addition, by controlling the heating temperature and the thermocompression bonding time in the previous thermocompression bonding as described above, the shape of the hot melt layer 3 after curing becomes a shape close to that of the hot melt layer 3 before curing, so that it is easy to peel off. In addition, since the thermoplastic resin does not transfer onto the uneven surface 11, it is possible to prevent adhesive residue, breakage of the uneven surface 11, and the like.

  As described above, in the dust removing method in the present embodiment, the hot melt layer 3 of the dust removing material 1 is configured in the thermocompression bonding between the dust removing material 1 and the uneven surface 11 having the dust 12 on the surface. By setting the temperature to be equal to or higher than the glass transition temperature of the thermoplastic resin and not higher than the softening temperature of the thermoplastic resin, dust can be reliably captured and removed. In addition, the thermoplastic resin does not adhere more than necessary to the minute concavo-convex surface 11 such as a microlens, whereby the above-described troubles in peeling can be suppressed.

  Furthermore, the hot melt layer 3 is composed of a plurality of thermoplastic resins having different softening temperatures, and is subjected to thermocompression bonding at a temperature lower than the softening temperature of the thermoplastic resin having a relatively low softening temperature. As a result, a wide range of thermocompression bonding conditions can be set without causing the melting to proceed sharply, and problems such as dropping of the hot melt layer 3 are suppressed.

  The dust removing method can easily and reliably remove the dust on the uneven surface 11 of the microlens by performing such a process.

  In the present embodiment, it is possible to construct a system that continuously performs a series of steps of the above-described dust removing method by making the shape of the dust removing material 1 long.

  FIG. 3 is a diagram illustrating an example of a dust removal system that performs a series of steps while unwinding the long sheet-shaped dust removing material 1. In this dust removing system, the dust removing material 1 is continuously supplied from the unwinding roll 21. The dust removing material 1 to which the dust has adhered is wound up on the winding roll 22. When supplying the dust removing material 1, the cover sheet 24 is peeled off by the auxiliary roll 23, and the dust removing material 1 is fed out with the hot roll layer exposed.

  In the example shown in FIG. 3, the work (dust removal target) 25 is a solid-state image sensor such as a CCD or CMOS, and removes dust adhering to the microlens surface of the solid-state image sensor. The workpiece 25 is placed on the heater 26 and heated, and then placed on the cooler 27 to be cooled.

  The delivered dust removing material 1 is pressed against the workpiece 25 by the pressing head 28. An elastic body 29 made of rubber or the like is attached to the tip of the pressing head 28, and thereby a good pressure-bonding state is realized following the fine uneven surface of the work 25. Here, the elastic body 29 of the pressing head 28 preferably has a rubber hardness based on JIS K6253 in the range of Shores A40 to A70.

  In the dust removing system shown in FIG. 3, first, the dust removing material 1 is supplied from the unwinding roll 21 as shown in FIG. At this time, the dust removing material 1 is supplied so that the surface of the hot melt layer 3 faces the workpiece 25 side. Further, the work 25 is placed on the heater 26 and heated. Next, as shown in FIG. 3B, the heater 26 on which the work 25 is placed is moved directly below the pressing head 28. Then, the pressing head 28 is lowered to press the dust removing material 1 supplied from the unwinding roll 21 from the back side thereof, and the dust removing material 1 is thermocompression bonded to the surface (uneven surface) of the work 25 on the heater 26. .

  After performing the thermocompression bonding for a predetermined time, as shown in FIG. 3C, the work 25 is moved onto the cooler 27 while the dust removing material 1 is being crimped. By moving the workpiece 25 to the cooler 27, the dust removing material 1 is cooled together with the workpiece 25, and the hot melt layer returns to room temperature. During this time, the next workpiece 25 is replenished on the heater 26 and heating is started.

  After the hot melt layer of the dust removing material 1 placed on the cooler 27 returns to room temperature, the pressing head 28 is raised to peel the dust removing material 1 from the surface of the workpiece 25 as shown in FIG. Then, dust on the surface of the workpiece 25 is removed. After removing the dust, as shown in FIG. 3 (e), the dust removing material 1 on the portion to which the dust has adhered is taken up by the take-up roll 22, and the unused portion of the dust removing material 1 is fed out. Thereafter, as shown in FIG. 3F, the work 25 on the cooler 27 is moved to the next step. At the same time, the process returns to the step of FIG. 3A, and the series of steps is repeated to continuously remove dust on the surface of the workpiece 25.

  In this dust removal system, the dust removal material 1 is heated and cooled by the heater 26 and the cooler 27, which are support bases for supporting the workpiece 25, respectively. Instead, for example, as shown in FIG. The dust removing material 1 may be heated and cooled on the pressing head 28 side.

  In the dust removing system shown in FIG. 4, first, the dust removing material 1 is supplied from the unwinding roll 21 as shown in FIG. Further, the work 25 is placed on the support base 31. At this time, the dust removing material 1 is supplied so that the surface of the hot melt layer 3 faces the workpiece 25 side. Next, as shown in FIG. 4B, the pressure head 28 is heated, and the dust removing material 1 supplied from the unwinding roll 21 is thermocompression bonded to the surface (uneven surface) of the work 25. Next, as shown in FIG. 4C, the pressing head 28 is cooled, thereby cooling the dust removing material 1 and returning the hot melt layer of the dust removing material 1 to room temperature. After the hot melt layer returns to room temperature, the pressure head 28 is raised to peel the dust removing material 1 from the surface of the workpiece 25, and dust on the surface of the workpiece 25 is removed. After removing the dust, as shown in FIG. 4 (d), the dust removing material 1 at the portion where the dust is attached is wound up by the winding roll 22, and the unused portion of the dust removing material 1 is fed out. Then, as shown in FIG.4 (e), the workpiece | work 25 on the cooler 27 is moved to the following process. At the same time, the process returns to the step of FIG. 4A, and the series of steps is repeated to continuously remove dust on the surface of the workpiece 25.

  As described above, according to the dust removing material and the dust removing method in the present embodiment, it is possible to reliably remove the dust on the uneven surface such as the microlens array, and the like, such as resin transfer and uneven surface damage. It is possible to realize highly reliable dust removal without causing a failure. In addition, it cannot be overemphasized that this invention is not limited to the above-mentioned embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  Next, specific examples of the present invention will be described. The scope of the present invention is not limited to the following examples.

≪ (1) Production of dust removing material≫
First, five types of thermoplastic resins (resins A to E) having the properties shown in the following [Table 1] (glass transition temperature (° C.), softening temperature (° C.), molecular weight, melt viscosity) are shown in the following [Table 2]. The composition for forming a hot melt layer was prepared by blending in the parts by mass shown in FIG. Here, the resins A to E are polyester resins having the properties shown in [Table 1]. Next, a thermoplastic resin composition having a thickness of 30 μm is prepared by applying a solution obtained by mixing 100 parts by mass of the composition for forming a hot melt layer, 100 parts by mass of methyl ethyl ketone, and 200 parts by mass of toluene onto a polyester film having a thickness of 100 μm. Samples 1 to 9 of the dust removing material were prepared by forming a layer (hot melt layer).

  Samples 1 to 6, 8, and 9 correspond to examples of the present invention, and sample 7 corresponds to a comparative example.

  The dynamic viscoelasticity of the hot melt layers of Samples 1 to 7 was measured with a dynamic viscoelasticity device (DMA) (trade name DMA600 (manufactured by Seiko Shin Slums Co., Ltd.). The dynamic viscoelasticity was measured including the polyester film supporting the melt layer, and the measurement results are shown in Fig. 5. This figure shows the loss elastic modulus (E ") corresponding to the viscosity of the thermoplastic resin and the elasticity. 5 shows the temperature dependence of the loss tangent (tan δ), which reflects the vibration absorption, and is the ratio to the storage elastic modulus (E ′) corresponding to the curve (a) to (g) in FIG. Corresponds to the temperature dependence of the loss tangent (tan δ) of each of samples 1 to 7. Sample 1 to samples 1 to 7 each have a peak of the loss tangent (tan δ) at a predetermined temperature shown on the horizontal axis of FIG. In the present embodiment, the processing in thermocompression bonding The thermal temperature is higher than the glass transition temperature of Samples 1 to 7. In the temperature range of Fig. 5, the glass transition temperature is about 65 ° C for Sample 1 (curve (a)) and about 2 for Sample 2. 58 ° C. (curve (b)), sample 3 has about 10 ° C. and about 54 ° C. (curve (c)), sample 4 has about 13 ° C. and about 50 ° C. (curve (d)), sample 5 is about 7 ° C. and about 45 ° C. (curve (e)), and sample 6 is about 7 ° C. (curve (f)).

≪ (2) Identification of thermocompression bonding time≫
The dust removing material of Sample 3 was bonded to the glass substrate by thermocompression bonding, and then cooled and peeled off, and a test for confirming the appearance of the glass substrate and whether or not peeling was possible was performed. Specifically, the dust removing material was stacked on the glass substrate so that the hot melt layer was in contact with the glass substrate, and was pressed with a hand roller while being heated with a hot plate heated to 120 ° C. Then, it cooled to normal temperature and peeled the dust removing material. Here, the peeling angle was 180 °.

  Table 3 shows the results of the appearance of the glass substrate and whether or not it can be peeled when this test was performed with the thermocompression bonding time set to 5 seconds, 15 seconds, 30 seconds, 45 seconds, and 60 seconds. Although this glass substrate does not have an uneven surface, there is no problem because this test is merely a test for determining a good pressure bonding time condition. In [Table 3], “HM” means hot melt.

  When the thermocompression bonding time was 5 seconds, 15 seconds, and 30 seconds, it was easily peelable. And the change on an external appearance was not seen by the glass substrate after peeling, and the original glass substrate. That is, the thermoplastic resin of the hot melt layer was not transferred onto the glass substrate.

  On the other hand, when the thermocompression bonding time was 45 seconds or longer, it was not possible to peel easily or not at all. Then, the thermosetting resin of the hot melt layer is transferred and adhered onto the glass substrate, and peeling occurs at the interface between the polyester film as the base material of the dust removing material and the hot melt layer, and the hot melt layer is heated on the glass substrate surface. The thermosetting resin of the layer has remained.

  From this test result, it was found that when the thermocompression bonding temperature is 120 ° C., the thermocompression bonding time is preferably 5 to 30 seconds.

≪ (3) Thermocompression test (dust removal test etc.) ≫
A hot-melt layer of the dust removing material of Samples 1 to 9 was placed in contact with the lens surface in a microlens array having a lens radius of 2 μm and a center distance between adjacent lenses of 30 μm. A dust filler having an average particle diameter of about 4 μm and a maximum particle diameter of 20 μm or less was distributed on the lens. Thereby, the presence of about 10 particles / mm ² of foreign matter (mainly dust filler) was confirmed with a microscope. A resist layer is formed in the concave portion between the lenses.

Next, a 120 ° C. elastic body heating head (Shore A50 based on JIS K6253) is brought into contact with the polyester film surface of the dust removing material, heated at a pressure of 500 g / m ² for 30 seconds, and hot melted between the curved lens surface and the lens. The layer was thermocompression bonded. After thermocompression bonding, the dust removing material was left until it returned to room temperature, and the dust removing material was peeled off from the lens surface at an angle of 90 °. After peeling, (1) peeling strength, (2) presence / absence of microlens destruction, (3) dust removal state, and (4) resin transfer state in Samples 1 to 9 were examined. A similar test was also performed for a heating temperature of 120 ° C. and a thermocompression bonding time of 10 seconds, and a heating temperature of 80 ° C. and a thermocompression bonding time of 30 seconds. Hereinafter, the evaluation method will be described and the evaluation results are shown in [Table 4].

(1) Peel strength Using Tensilon (manufactured by Orientec Co., Ltd.) as a measuring device, the peel strength of Samples 1 to 9 was measured at a peel rate of 5 m / min. If a peel strength of 100 g / cm or more is obtained as a measurement result, it can be said that the peel strength is sufficient. This is because if the peel strength is less than 100 g / cm, the dust removing material may peel off during work.

(2) Destruction of microlens After the dust removing material was peeled off under the condition (1), whether or not the surface of the microlens was destroyed was visually confirmed using a microscope having a magnification of 200 times. Here, the case where the surface of the microlens was not broken was evaluated as “◎”. On the other hand, the case where destruction was confirmed on the surface of the microlens was evaluated as “x”.

(3) Observation of dust removal After the dust removing material was peeled off under the condition (1), whether or not the dispersed dust filler was removed was visually confirmed using a microscope with a magnification of 200 times.

  Here, the case where the dust filler was completely removed in the first dust removing operation was evaluated as “◎”. Also, some dust filler is confirmed in the first dust removal operation, but the dust filler can be completely removed by performing the (second) dust removal operation again, and there is no practical problem. Evaluated as “◯”. On the other hand, in the first dust removal operation, a case where a large amount of dust filler remained was evaluated as “x”.

(4) Observation of transfer of hot melt layer Whether or not the hot melt layer was transferred to the surface of the microlens after peeling the dust removing material under the condition (1) using a microscope with a magnification of 200 times. It was confirmed visually.

  Here, the case where there was no transfer of the hot melt layer in one dust removal operation was evaluated as “◎”. On the other hand, although transfer of the hot melt layer was confirmed in one dust removal operation, the case where there was no practical problem was evaluated as “◯”. On the other hand, the case where transfer of the hot melt layer was clearly confirmed in one dust removal operation was evaluated as “x”. In addition, unlike the dust, it was difficult to remove the hot melt layer even if the removal operation was performed again.

(5) Comprehensive evaluation The dust removing material in the present embodiment requires thermocompression bonding conditions for obtaining results that are satisfactory in all the evaluations of (1) to (4). Therefore, two or more of the above three conditions in thermocompression bonding (heating temperature 120 ° C. and thermocompression bonding time 30 seconds, heating temperature 120 ° C. and thermocompression bonding time 10 seconds, heating temperature 80 ° C. and thermocompression bonding time 30 seconds) In the condition, the case where all the evaluations of (1) to (4) are satisfied is evaluated as “◎”, and the case where all the evaluations in (1) to (4) are satisfied only under one condition is set as “◯” evaluated. On the other hand, the case where all the evaluations (1) to (4) were not satisfied under any condition was evaluated as “x”.

  As shown in [Table 4], samples 1, 6, 8, and 9 having a softening temperature in the range of 110 to 170 ° C. obtained good evaluation results for each evaluation item in one of the three conditions of thermocompression bonding. It was found that it can be used practically. In addition, sample 2 in which resin A having a softening temperature of 120 ° C. and resin B having a softening temperature of 165 ° C. is blended at a blending ratio of 1: 9 is good for each evaluation item in one of the three thermocompression bonding conditions. An evaluation result was obtained, and it was found that it could be used practically. In addition, it was found that samples 3 and 5 can be used practically under two of the three thermocompression bonding conditions and sample 4 under all three thermocompression bonding conditions.

  From this result, when using a thermoplastic resin having a softening temperature in the range of 110 ° C. to 170 ° C., a predetermined blend of a plurality of thermoplastic resins having different softening temperatures is used rather than using one kind of thermoplastic resin. It has been found that the use of a material blended in a ratio gives a more preferable result in practical use of the dust removing material. Moreover, it turned out that it is preferable that the softening temperature of these several thermoplastic resins is the range of 110 to 170 degreeC, respectively.

  And among a plurality of thermoplastic resins, the blending ratio (A) / low softening temperature thermoplastic resin (A) and high softening temperature thermoplastic resin (B) each having a softening temperature in the range of 110 ° C to 170 ° C. It was found that (B) = 3/7 to 9/1 is particularly preferable.

  Next, a sample of a typical dust remover (samples 1, 4, and 6) was peeled off by pressing on the surface of the CMOS sensor, peel strength was measured, and microscopic images of the surface of the CMOS sensor and the sample surface were taken. .

Specifically, first, a CMOS sensor (1 cm square) was attached to a glass plate with a double-sided tape, and a microscope image of the lens surface of the CMOS sensor was taken (FIG. 6A). Next, dust (trade name P-4) was dispersed on the lens surface of the CMOS sensor and diffused by air blow, and a microscope image of the lens surface of the CMOS sensor was taken (FIG. 6B). Next, a DR sheet (samples 1, 4, 6) was set on the durometer, and the DR sheet was pressed against the lens surface of the CMOS sensor at a speed of 5.7 and a weight of 500 g / cm ² . Thermocompression bonding was performed with a thermocompression bonding time of 30 seconds. Next, the DR sheet was peeled off with ACF Tensilon at a speed of 5 mm / min. The peel strength was measured, and after peeling, microscopic images of the lens surface and DR sheet surface of the CMOS sensor were taken (FIGS. 6 (c) and 6 (d), respectively).

  As shown in FIG. 6C, in Sample 1, the thermosetting resin of the hot melt layer was transferred and remained on the lens surface of the CMOS sensor. This is presumably because the peel strength between the hot melt layer and the lens surface of the CMOS sensor was greater than the peel strength (adhesive strength) between the hot melt layer and the polyester film. The peel strength of Sample 1 under the above measurement conditions was 484 g. In sample 4, the resin was not transferred to the lens surface of the CMOS sensor, and dust was removed cleanly. The peel strength of Sample 4 under the above measurement conditions was 223 g. In sample 6, the resist on the lens surface of the CMOS sensor was broken. This is presumably because the peel strength between the hot melt layer and the polyester film and the peel strength between the hot melt layer and the lens surface were both large. The peel strength of Sample 6 under the above measurement conditions was 408 g. As for sample 1, as shown in FIG. 6D, the glue on the sheet side of the sample was destroyed, and an image could not be taken.

DESCRIPTION OF SYMBOLS 1 Dust removal material, 2 Plastic film, 3 Hot melt layer, 3A Low softening temperature thermoplastic resin, 3B High softening temperature thermoplastic resin, 11 Uneven surface, 12 Dust, 21 Unwinding roll, 22 Winding roll, 23 Auxiliary roll , 24 cover sheet, 25 workpiece, 26 heater, 27 cooler, 28 pressing head, 29 elastic body, 31 support base

Claims (15)

A dust removing material for forming a hot melt layer on a surface of a support, pressing the hot melt layer on a concave / convex surface of an object to be removed, and cooling the dust to remove the dust attached to the concave / convex surface,
The dust removing material, wherein the hot melt layer is a thermoplastic resin composition layer formed of a plurality of thermoplastic resins having different softening temperatures.   The hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature, and the low softening temperature thermoplastic resin and the The dust removing material according to claim 1, which is a thermoplastic resin composition layer in which the softening temperature of the high softening temperature thermoplastic resin is in the range of 110 to 170 ° C. The hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature, and the low softening layer based on the formula (1) The dust removing material according to claim 1, wherein an average softening temperature of the temperature thermoplastic resin and the high softening temperature thermoplastic resin is in a range of 110 ° C to 170 ° C.
Formula (1): Average softening temperature (° C.) = WL × TL + WH × TH
WL: Weight ratio of low softening temperature thermoplastic resin WH: Weight ratio of high softening temperature thermoplastic resin TL: Softening temperature of low softening temperature thermoplastic resin TH: Softening temperature of high softening temperature thermoplastic resin   The dust removing material according to any one of claims 1 to 3, wherein the thermoplastic resin is a polyester resin.   A dust removing material, wherein a hot melt layer is formed on a surface of a support, and the hot melt layer is thermocompression-bonded to an uneven surface of a dust removal object and then cooled to remove dust attached to the uneven surface. The hot-melt layer is a thermoplastic resin composition layer formed of a thermoplastic resin having a softening temperature in the range of 110 ° C to 170 ° C. A dust removing method for removing dust on an uneven surface of a dust removal object with a dust removing material having a hot melt layer formed on a surface of a support,
After forming the hot melt layer as a thermoplastic resin composition layer comprising a plurality of thermoplastic resins having different softening temperatures, and thermocompression bonding the hot melt layer to the uneven surface at a temperature lower than the softening temperature of the thermoplastic resin Cooling and peeling off the dust removing material from the uneven surface. The hot melt layer contains a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature, and the low softening temperature thermoplastic resin and the A thermoplastic resin composition layer in which the softening temperature of the high softening temperature thermoplastic resin is in the range of 110 to 170 ° C., respectively.
The hot melt layer is thermocompression-bonded to the uneven surface at a temperature not higher than the softening temperature of the low softening temperature thermoplastic resin, and then cooled, and the dust removing material is peeled from the uneven surface. The dust removal method as described. Forming the hot melt layer as a thermoplastic resin composition layer comprising a low softening temperature thermoplastic resin having a relatively low softening temperature and a high softening temperature thermoplastic resin having a relatively high softening temperature; The low softening temperature thermoplastic resin based on the formula (1) and the high softening temperature thermoplastic resin are formed as a thermoplastic resin composition layer having an average softening temperature in the range of 110 ° C to 170 ° C.
The hot melt layer is thermocompression-bonded to the uneven surface at a temperature not higher than the softening temperature of the low softening temperature thermoplastic resin, and then cooled, and the dust removing material is peeled from the uneven surface. The dust removal method as described.
Formula (1): Average softening temperature (° C.) = WL × TL + WH × TH
WL: Weight ratio of low softening temperature thermoplastic resin WH: Weight ratio of high softening temperature thermoplastic resin TL: Softening temperature of low softening temperature thermoplastic resin TH: Softening temperature of high softening temperature thermoplastic resin   The dust removal method according to any one of claims 6 to 8, wherein a heating temperature in the thermocompression bonding is equal to or higher than a glass transition temperature of the low softening temperature thermoplastic resin.   The back side of the object to be removed with the uneven surface is supported by a support base, and the dust removing material is pressed against the uneven surface by a pressing head having at least a tip portion made of an elastic body. The dust removing method according to claim 9, wherein the removing material is heated and cooled.   The back side of the dust removal object having the uneven surface is supported by a support base, and the dust removing material is pressed against the uneven surface by a pressing head having at least a tip portion made of an elastic body. The dust removing method according to claim 9, wherein the removing material is heated and cooled.   The dust removing method according to claim 10 or 11, wherein the long dust removing material is sequentially fed out.   The dust removing method according to claim 6, wherein the uneven surface is a surface of a microlens.   The dust removing method according to any one of claims 6 to 13, wherein a polyester resin is used as the thermoplastic resin. A dust removing method for removing dust on an uneven surface of a dust removal object having an uneven surface of the dust removal object by a dust removing material having a hot melt layer formed on a surface,
The hot melt layer is formed as a thermoplastic resin composition layer containing a thermoplastic resin having a softening temperature in the range of 110 to 170 ° C.
Dust removal, wherein the hot melt layer of the dust removing material is thermocompression-bonded to the uneven surface at a temperature not higher than the softening temperature of the thermoplastic resin, and then cooled to peel the dust removing material from the uneven surface. Method.

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