JP4410615B2 - Shielding blade and optical path opening / closing device using the same - Google Patents

Description

  The present invention relates to a light shielding blade for opening and closing an optical path in an optical apparatus such as a camera and an optical path opening and closing device using the light shielding blade.

  In an optical path opening / closing device such as a shutter or diaphragm that opens and closes the optical path of an optical device such as a camera, the light shielding blades constituting the shutter blades and diaphragm blades must move and stop so as to cross the optical path in a very short time. In order to reduce the load on the drive source, it is desired to be lightweight and highly rigid. In addition, these light-shielding blades need to shield light from a photoconductor such as a film or a CCD. Therefore, the light-shielding blade is required to have a light-shielding property, a low surface reflectance, and a certain level of flatness. Furthermore, many optical path opening and closing devices are configured to operate with a plurality of light shielding blades being overlapped, and lubricity and antistatic properties of contact portions that overlap each other are required. The flatness of the surface of the light shielding blade described above is important in preventing damage due to collision with the adjacent light shielding blade during the operation.

  In order to satisfy the characteristics required for such light shielding blades, those using various materials have been proposed. For example, Patent Document 1 discloses a camera shutter that uses at least one metal layer between film layers of a crystalline polymer compound such as a plurality of polyesters as a light shielding unit. Further, it teaches that a light shielding means is provided by sandwiching one or more coating layers of black paint or the like between plastic film layers. In addition, it is disclosed that at least one layer of the plastic film contains a black pigment or a black dye. In Patent Document 2, a thermosetting matte paint is coated on a biaxially stretched polyester film having a composition with a film thickness of about 100 μm or less, preferably 70 μm or less and an optical density of about 10 or more. Furthermore, a plastic blade for an optical device to which an antistatic material is attached is disclosed. Patent Document 3 uses a film mainly composed of a thermoplastic resin as a base film, and is provided with a light-shielding film by providing layers made of a thermosetting resin containing carbon black, a lubricant, and a matting agent on both sides. Configuration is disclosed. Patent Document 4 discloses a light shielding blade for a camera made of an aluminum alloy material, and Patent Document 5 applies a carbon fiber reinforced thermosetting resin thin plate (hereinafter referred to as CFRP) to the shutter blade. In addition, it is disclosed that light shielding properties can be obtained by mixing a black pigment containing carbon black or the like into the matrix resin. Further, Patent Document 6 discloses CFRP with less warping, and Patent Document 7 discloses that CFRP has light weight, high strength, high elasticity, impact resistance, and vibration damping.

JP 57-60315 A JP-A-57-118226 JP-A-9-274218 JP 57-24925 A JP 49-84232 A Japanese Patent Laid-Open No. 51-14969 JP-A-53-101080

  A light-shielding blade made of polyethylene terephthalate (hereinafter referred to as PET) is widely used in low-price cameras and the like because of its low manufacturing cost and low specific gravity. However, since PET has low mechanical strength such as tensile elastic modulus, the light shielding blades bend due to vibrations or shocks that occur during running or braking. It cannot be used with a focal plane shutter that travels at

  In addition, a light-shielding blade made of a metal such as an aluminum alloy has high mechanical strength and can be incorporated into a high-speed shutter device, but the weight of the light-shielding blade itself is increased due to the large specific gravity of the material itself. , Requires large charge energy. Furthermore, vibrations that occur during running and braking, so-called undulations, are very large, and this undulation state is not easily settled.

  On the other hand, the light-shielding blade made of CFRP is lightweight and has a high elastic modulus, and even when the shutter speed is high, there is very little undulation during running and braking, and even if undulation occurs, it quickly decays. It has the characteristic to end. Accordingly, there is no possibility of collision between the light shielding blades and damage due to this, and extremely high durability can be realized. However, CFRP is expensive in material itself and needs to be manufactured in a very laborious process in which a plurality of prepreg sheets, which are precursors at the time of manufacture, are laminated and heated while being pressed. is there. In addition, the sheet thus obtained is also likely to have defects such as openings due to variations in carbon fiber, and has a high defect generation rate due to variations in strength and warpage, which takes time for quality control. In combination with this, the manufacturing cost becomes very high.

  By the way, when a liquid crystal polymer (hereinafter sometimes referred to as LCP), which is known as an engineering plastic and has a low density similar to that of general polymer substances, is formed into a film by extrusion molding, each domain (polymer chain) Each molecule oriented in a random direction is aligned along the extrusion direction and exhibits orientation. Thereby, LCP exhibits high strength and high elasticity not found in general polymer materials. In other words, since the mechanism of high elasticity in LCP depends on the orientation of domains in the molding direction, the elastic modulus shows anisotropy and has a high elastic modulus along the molding direction. In most cases, the elastic modulus in the orthogonal direction is extremely low. As a result, an LCP film that can be easily split along the forming direction is often produced. Considering the use of LCP as a structural material, the remarkable anisotropy of the elastic modulus as described above causes a lack of reliability and makes its practical use difficult.

  An object of the present invention is to provide an inexpensive light-shielding blade having high strength and stable quality, and an optical path switching device using the same.

The light-shielding blade of the present invention that achieves this object comprises a thermoplastic resin film other than a liquid crystal polymer, and a plurality of liquid crystal polymer films that are symmetrically laminated with the thermoplastic resin film interposed therebetween, and the thermoplastic resin film The crystal orientation directions of the pair of liquid crystal polymer films at symmetrical positions with respect to each other are parallel to each other or cross each other.
The optical path switching device of the present invention is an optical path switching device using the light shielding blade, wherein the crystal orientation directions of the liquid crystal polymer film forming a pair intersect geometrically symmetrically with respect to the moving direction of the light shielding blade. Or the crystal orientation direction of the pair of liquid crystal polymer films located in the outermost layer is substantially orthogonal to the moving direction of the light shielding blade.

  According to the light-shielding blade of the present invention, it is possible to realize an inexpensive light-shielding blade having high strength and high elasticity and having stable quality.

  According to the optical path switching device of the present invention, the light shielding blade according to the present invention is used, and the crystal orientation direction of the liquid crystal polymer film forming a pair is crossed geometrically symmetrically with respect to the moving direction of the light shielding blade, or the outermost layer is formed on the outermost layer. By making the crystal orientation direction of the paired liquid crystal polymer film almost orthogonal to the moving direction of the light shielding blade, it is easy to manufacture, has high strength and high elasticity, and uses a light shielding blade with little warpage It is possible to realize the optical path switching device.

  A first aspect of the present invention comprises a thermoplastic resin film other than a liquid crystal polymer, and a plurality of liquid crystal polymer films laminated symmetrically across the thermoplastic resin film, with the thermoplastic resin film as a reference The light-shielding blade is characterized in that crystal orientation directions of the pair of liquid crystal polymer films in a symmetrical lamination position are parallel to each other or cross each other.

  Specifically, when a light shielding blade having a three-layer structure is formed using two LCP films, a thermoplastic resin film (hereinafter referred to as a thermoplastic resin, this is intentionally free of LCP). The two LCP films can be laminated so that the crossing angle in the crystal orientation direction is 0 °, that is, parallel, for example, 60 ° or 90 °. Further, when a light shielding blade having a five-layer structure is configured by using four LCP films, the crystal orientation direction of the LCP film is, for example, 0 ° in order based on the crystal orientation direction of the LPC film on one side in the stacking direction (0 °). It is possible to laminate the film by crossing such as / 45 ° / thermoplastic resin film / 135 ° / 0 ° or crossing such as 0 ° / 60 ° / thermoplastic resin film / 120 ° / 0 °.

  The LPC used in the present invention is preferably a wholly aromatic LPC from the viewpoint of mechanical strength, and thermotropic LPC which is a kind of polyester resin is particularly effective.

  As a method for forming such an LCP into a film, a known method can be used, but a method of kneading and extruding in a molten state is preferable from an industrial viewpoint. For example, using a uniaxial or biaxial extruder, the molten resin is extruded from a T die and wound after uniaxial stretching or biaxial stretching, or the molten resin is extruded cylindrically from an annular die, cooled and wound The inflation film-forming method to take can be mentioned. In the present invention, among the films formed by such extrusion, the film extrusion direction (hereinafter referred to as MD direction) and the direction perpendicular to the MD direction in the film plane (hereinafter referred to as TD direction). And those having a large anisotropy in mechanical strength. In particular, a film having a ratio of a bending elastic modulus in the MD direction to a bending elastic modulus in the TD direction, that is, anisotropy of the bending elastic modulus (hereinafter referred to as MD / TD) is preferably in the range of 3 to 40. .

Also, an LCP film having a molecular orientation ratio (SOR: Segment Orientation Ratio) of 1.1 to 1.6 is preferable because of its high bending elastic modulus in the MD direction. This degree of molecular orientation (hereinafter referred to as SOR) is an index that gives the degree of molecular orientation of the segments constituting the molecule, and is different from the conventional MOR (Molecular Orientation Ratio) and is not related to the thickness of the sample. Value. This SOR is calculated as follows. That is, first, in a known microwave molecular orientation measuring instrument, this is inserted into a microwave resonant waveguide so that the surface of the LPC film as a sample is perpendicular to the traveling direction of the microwave. The electric field intensity of the transmitted microwave, that is, the microwave transmission intensity is measured. And based on this measured value, the refractive index m is calculated by the following formula 1.
m = (Z ₀ / Δz) × (1−ν _max / ν ₀ ) (Formula 1)
In Equation 1, Z ₀ is a constant of the apparatus, Δz is the average film thickness of the sample, ν _max is the frequency that gives the maximum microwave transmission intensity when the microwave frequency is changed, and ν ₀ is the average film thickness. This is the frequency that gives the maximum microwave transmission intensity when 0, that is, when there is no sample.

When the rotation angle of the sample with respect to the microwave vibration direction is 0 °, that is, the vibration direction of the microwave matches the direction in which the sample molecules are best oriented and give the minimum microwave transmission intensity. the refractive index m of the time and m _0, if the rotation angle of the sample was an index of refraction m when the 90 ° and m _90, SOR is represented by m ₀ / m _90.

  When MD / TD showing the anisotropy of the flexural modulus is less than 3 or SOR is less than 1.1, the difference in mechanical strength based on the anisotropy of the flexural modulus becomes small, and the crystal orientation direction in the film plane However, the mechanical strength becomes small, and for example, the high strength and high elasticity required for a shutter blade operating at high speed cannot be satisfied. Further, when MD / TD exceeds 40 or SOR exceeds 1.6, the strength of the film in the TD direction is too weak, and accidents that easily tear in the forming direction frequently occur.

  By the way, if the number of laminated LCP films having different crystal orientation directions increases, the anisotropy of the flexural modulus is relaxed and approaches isotropic, which is an obstacle to obtaining the remarkable effect of the present invention. In addition, if the number of laminated layers is large, the man-hours for the production increase and the productivity also deteriorates. Therefore, 3 to 9 layers in total including the thermoplastic film, preferably 3 to 5 layers, that is, 2 sheets Or it is optimal to laminate | stack four LCP films so that one thermoplastic film may be pinched | interposed.

  In the light-shielding blade according to the first aspect of the present invention, the crystal orientation directions of the pair of liquid crystal polymer films located in the outermost layer may be parallel to each other as in the above-described example.

When the crystal orientation directions of a pair of liquid crystal polymer films located in the outermost layer are parallel to each other, for example, a biaxially stretched PET film is used as a thermoplastic resin film, and the crystals of two LCP films are sandwiched between the PET films. When laminated with the orientation directions parallel, the bending elastic modulus in the MD direction of the LCP film constituting the outermost layer is E ₁ , the thickness is T _1, and the bending elastic modulus of the PET film located at the center of the laminating direction is E ₂ , where the thickness is T ₂ , the thickness H of the laminated light shielding blades is 2T ₁ + T ₂ , so the overall bending elastic modulus E of the light shielding blades is calculated by the following equation 2. .
E = [E ₂ T ₂ ³ + E ₁ {(2T ₁ + T ₂ ) ³ −T ₂ ³ }] / H ³ (Formula 2)
Assuming T ₁ = T ₂ = T and H = 3T, the above equation 2 is E = (E ₂ + 26E ₁ ) / 27 (Equation 3)
It becomes. That is, the bending elastic modulus in the MD direction of the LCP film located in the outermost layer contributes 26 times to the bending elastic modulus of the entire light shielding blade as compared with the bending elastic modulus of the PET film located in the center in the laminating direction. In other words, with respect to the mechanical strength of the light shielding blade, the physical properties of the LCP film located in the outermost layer greatly affect the crystal orientation direction of the LCP film located in the outermost layer with respect to the moving direction of the light shielding blade in the usage form. It is extremely effective to make them orthogonal. However, in order to obtain a physical balance of the light shielding blades, it is preferable that the crystal orientation directions of the respective LCP films are geometrically symmetrical with respect to a direction orthogonal to the moving direction of the light shielding blades.

  When the crystal orientation directions of the pair of liquid crystal polymer films located on the outermost layer are parallel to each other, the crystal orientation directions of the pair of liquid crystal polymer films located on the inner side of the outermost layer are as in the example of the five-layer structure described above. It is preferable to cross geometrically symmetrically with respect to the crystal orientation direction of the pair of liquid crystal polymer films located in the outermost layer.

  As the thermoplastic resin, well-known resins such as polyester, polyolefin, and polyamide can be adopted, and polyester resins such as PET, polybutylene terephthalate, and polyethylene naphthalate are particularly preferable.

  The ratio of the thickness of the thermoplastic resin film to the thickness of the entire light shielding blade is preferably about 20 to 80%. When the ratio of the thermoplastic resin is 20% or less, a LCP film and a thermoplastic resin film are easily laminated, particularly when heat welding or ultrasonic welding is performed, and the LCP located in the outermost layer. The intensity | strength of the light-shielding blade of the direction orthogonal to the crystal orientation direction of a film will become weak. For this reason, a light-shielding blade will tear easily along the crystal orientation direction of the LCP film located in the outermost layer. Conversely, if the ratio of the thermoplastic resin exceeds 80%, the strength of the light shielding blade along the crystal orientation direction of the LCP film located in the outermost layer becomes about half, and the high elasticity characteristic of the liquid crystal polymer is reduced. The result is lost. Moreover, at present, about 10% of the thickness of the light shielding blade is the limit of the thickness of one LCP film.

Incidentally, when the thickness of the thermoplastic resin film is 20% of the thickness of the light shielding blade, the elastic modulus E of the light shielding blade is T ₂ = T, T ₁ = 2T, and H = 5T. = (E ₂ + 124E ₁ ) / 125 (Formula 4)
It becomes. When the thickness of the thermoplastic resin film is 80% of the thickness of the light shielding blade, the elastic modulus E of the light shielding blade is T ₁ = T, T ₂ = 8T, and H = 10T. = (512E ₂ + 488E ₁ ) / 1000 (Formula 5)
It becomes.

  A light-shielding improvement layer containing a light-shielding agent can be formed between the thermoplastic resin film and the liquid crystal polymer film that overlap each other or between the two liquid crystal polymer films. It is possible to employ an agent. In this case, an adhesive in which a black pigment such as carbon black is mixed is applied between the thermoplastic resin film and the LCP film or between the two layers of LCP film, and these are overlapped, and the LCP film is integrated by heating or the like. It can be made. By integrating the thermoplastic resin film and the LCP film by heat welding or ultrasonic welding, it becomes possible to improve productivity, reduce manufacturing costs, and greatly improve recyclability. In particular, heat welding by hot pressing is preferable. In this case, the reliability and strength of adhesion and welding can be further increased by roughening the surface of the thermoplastic resin film by mat processing or the like.

  A light-shielding agent can be added to the thermoplastic resin film and at least one liquid crystal polymer film. In the case of dispersing the light-shielding agent in the thermoplastic resin film and the LCP film, a known method can be used, but a method of kneading each component in a molten state from an industrial viewpoint is preferable. For this melt-kneading, generally used single-screw or twin-screw extruders and various kneaders such as kneaders can be used, but a twin-screw high-kneader is particularly preferable. In kneading, the respective components may be mixed uniformly in advance with an apparatus such as a tumbler or a Henschel mixer. In some cases, the mixing may be omitted, and a method of separately supplying each of the components separately to the kneading apparatus may be adopted. Is possible.

  A functional layer having at least one of a light shielding property, a lubricating property, and an antistatic property can be formed on the surface of the liquid crystal polymer film located in the outermost layer.

  According to the light-shielding blade of the present invention, it comprises a thermoplastic resin film other than the liquid crystal polymer and a plurality of layers of liquid crystal polymer films laminated symmetrically with the thermoplastic resin film interposed therebetween, and is symmetrical with respect to the thermoplastic resin film. Since the crystal orientation directions of the pair of liquid crystal polymer films at the lamination position are parallel to each other or cross each other, a light-shielding blade having a strength higher than that of a biaxially stretched PET film is obtained when the thickness is the same. Can do. Further, the physical balance as the light shielding blade is improved, and it is possible to obtain a light shielding blade with very little occurrence of warpage. Furthermore, the material itself is opaque and excellent in light-shielding properties compared to PET having an optical density of almost 0, and an LCP film having a film thickness of 25 μm has an optical density of about 0.5. By laminating one or more sheets, the optical density can be increased to about 1.5 to 2, which is further advantageous in terms of light shielding properties.

  When the crystal orientation directions of the pair of liquid crystal polymer films located in the outermost layer are parallel to each other, a large mechanical strength as a light-shielding blade can be expressed, and in particular, the pair of liquid crystal polymer films located in the outermost layer By making the crystal orientation direction orthogonal to the moving direction of the light shielding blade, the mechanical strength required for the light shielding blade can be effectively exerted. In particular, when the crystal orientation direction of the pair of liquid crystal polymer films located on the inner side of the outermost layer is crossed geometrically symmetrically with respect to the crystal orientation direction of the pair of liquid crystal polymer films located on the outermost layer, light shielding The physical property balance as a blade can be further improved, and the occurrence of warpage can be reliably prevented.

  When the thermoplastic resin is a polyester resin, the molecular structure is close to that of the liquid crystal polymer compared to other thermoplastic resins, which is advantageous in terms of thermal weldability and warpage. Moreover, in the case of a polyamide resin, it cannot be said that there is a problem such as swelling due to moisture absorption.

  When a light-shielding improvement layer containing a light-shielding agent is formed between a thermoplastic resin film and a liquid crystal polymer film that overlap each other or between two liquid crystal polymer films, the light-shielding property of the resulting light-shielding blade can be improved. In addition, by forming the light-shielding improvement layer mainly using an adhesive, it is possible to reliably improve the bonding strength of the films that overlap each other.

  When a light-shielding agent is added to the thermoplastic resin film and at least one liquid crystal polymer film, there is no need for complicated work as in CFRP to which a light-shielding agent is added, and a light-shielding agent such as carbon black is used when forming an LCP film. Can be dispersed and kneaded, so that a larger amount of the light-shielding agent can be mixed uniformly, and the light-shielding characteristics can be further improved.

  In the case where a functional layer having at least one of light shielding properties, lubricity, and antistatic properties is formed on the surface of the liquid crystal polymer film located in the outermost layer, the function as a light shielding blade can be further improved.

  According to a second aspect of the present invention, there is provided an optical path opening / closing device using the light shielding blade according to the first aspect of the present invention, wherein the crystal orientation direction of the liquid crystal polymer film forming a pair is geometric with respect to the moving direction of the light shielding blade. The crystal orientation directions of the pair of liquid crystal polymer films located on the outermost layer are substantially orthogonal to the moving direction of the light shielding blades.

  The thickness of the light shielding blade is preferably in the range of 50 to 200 μm, and particularly effective in the range of 70 to 120 μm. When the thickness of the light shielding blade is less than 50 μm, the mechanical strength as the light shielding blade is insufficient and the light shielding property may be insufficient. On the other hand, when the thickness exceeds 200 μm, the mechanical strength increases, but the inertial mass increases with the increase in the weight of the light shielding blade itself, which places a burden on the drive system and the like. In particular, when employed in a focal plane shutter, the distance between the front film and the rear film is increased, and the shutter efficiency is reduced.

  According to the optical path switching device of the present invention, the light shielding blade according to the present invention is used, and the crystal orientation direction of the liquid crystal polymer film forming a pair is crossed geometrically symmetrically with respect to the moving direction of the light shielding blade, or the outermost layer is formed on the outermost layer. By making the crystal orientation direction of the paired liquid crystal polymer film almost orthogonal to the moving direction of the light shielding blade, it is easy to manufacture, has high strength and high elasticity, and uses a light shielding blade with little warpage It is possible to realize the optical path switching device.

  An embodiment in which the light-shielding blade according to the present invention is applied to a focal plane shutter will be described in detail with reference to FIGS. 1 to 4, but the present invention is not limited to such an embodiment, and is within the scope of the claims. All changes and modifications encompassed by the described inventive concept are possible and can of course be applied to other techniques belonging to the spirit of the invention.

  The front shape of the focal plane shutter unit according to the present embodiment is shown in FIG. 1, and the sectional structure taken along the line II-II is shown in FIG. In other words, this focal plane shutter unit 10 is called a so-called vertical running type, and as the leading film 11 and the trailing film 12, a plurality of sheets (5 sheets and 4 sheets in the illustrated example) that overlap each other are shielded. The blades 13, 14, 15, 16, 17, 18, 19, 20, 21 are used. The specific configuration of the focal plane shutter unit 10 itself is well known in Japanese Patent Laid-Open Nos. 10-186448, 2002-229097, 2003-280065, and the like.

  FIG. 3 shows an exploded state of one of the light shielding blades 13 to 21 in the present embodiment (hereinafter, these are represented by 13 for convenience), and FIG. 4 shows a sectional structure thereof. That is, the light shielding blade 13 of the present embodiment is formed by laminating one PET film 22 and two LCP films 23 and 24 so as to sandwich the film, and two LCP films 23 positioned in the outermost layer. , 24 are set parallel to each other. A black paint for improving the light shielding property is applied to both the front and back surfaces of the light shielding blade 13 to constitute the functional layer 25 in the present invention. Further, a light-shielding improvement layer 26 is formed between the PET film 22 and the LCP films 23 and 24 that overlap each other. In FIG. 1, the light shielding blades 13 in the present embodiment traveling in the vertical direction are each formed into a long and narrow rectangular plate shape, and the orientation direction of the two LCP films 23 and 24 located in the outermost layer is the longitudinal direction of the light shielding blade 13. It is cut out so as to extend parallel to the direction. Further, carbon black is uniformly dispersed and mixed in the PET film 22 and the LCP films 23 and 24 to improve the light shielding property. Similarly, carbon black is evenly distributed in the light-shielding improvement layer 26.

  Next, although the specific manufacturing method of the light-shielding blade by this invention is shown below with Comparative Examples 1-3 for comparative reference as Example 1-Example 5, all of these are film thickness of 5 micrometers on both front and back. The black paint was applied as a functional layer and dried. In the case of the light shielding blades on which the LCP films are laminated, the angle of the crystal orientation directions of the LCP films overlapping each other is expressed with the longitudinal direction of the light shielding blades as a reference (0 °).

Example 1
A raw material prepared by mixing 2% by weight of carbon black in Ueno LCP8000 manufactured by Ueno Pharmaceutical was prepared. Then, using Technovel KZW15-30MG2, the cylinder set temperature is 250 ° C, the die set temperature is 270 ° C, the molten raw material is extruded upward from the cylindrical die, and dry air is blown into the hollow portion of the cylindrical film formed thereby. The tubular film was expanded by pumping, then it was cooled, passed through a nip roll and wound up. As a result, a black LCP film having a thickness of 25 μm and an SOR of 1.28 was obtained.

On the other hand, a 25 μm thick biaxially stretched black PET film with a matte surface was prepared and sandwiched between the black LCP films, and the crystal orientation directions of these pair of black LCP films were set to 0 °, respectively. Set. Further, an epoxy adhesive mixed with 33% by weight of carbon black is applied between the PET film and the LCP film in a film thickness of about 5 μm, and the temperature is set to 120 ° C. without first applying a press pressure using a hot press. After preheating for 10 minutes, heat pressing is performed at a pressure of 5 kg / cm ² for 120 minutes while maintaining the processing temperature at 130 ° C., and these are integrated and a black paint is applied to both the front and back surfaces. The shading blade was manufactured by cutting into a shape.

(Example 2)
A black LCP film having a thickness of 25 μm was obtained in the same manner as in Example 1, while a 25 μm-thick biaxially stretched black PET film with a thickness of 25 μm was prepared. Then, the black PET film was sandwiched between the black LCP films, and the crystal orientation directions of the pair of black LCP films were set to 30 ° and 150 °, respectively. Further, an epoxy adhesive mixed with 33% by weight of carbon black was applied between the PET film and the LCP film in a film thickness of about 5 μm, and hot pressing was performed under the same conditions as in Example 1. Were integrated and black paint was applied to both the front and back surfaces, and then cut into a predetermined shape to produce a light shielding blade.

(Example 3)
A black LCP film having a thickness of 25 μm was obtained in the same manner as in Example 1, while a 25 μm thick biaxially stretched black PET film with a thickness of 25 μm was prepared. Then, the black PET film was sandwiched between the black LCP films, and the crystal orientation directions of the pair of black LCP films were set to 45 ° and 135 °, respectively. Further, an epoxy adhesive mixed with 33% by weight of carbon black was applied between the PET film and the LCP film in a film thickness of about 5 μm, and hot pressing was performed under the same conditions as in Example 1. Were integrated and black paint was applied to both the front and back surfaces, and then cut into a predetermined shape to produce a light shielding blade.

Example 4
A black LCP film having a thickness of 25 μm was obtained in the same manner as in Example 1, while a 25 μm-thick biaxially stretched black PET film with a thickness of 25 μm was prepared. Then, the black PET film is sandwiched between the black LCP films, the crystal orientation directions of the pair of black LCP films are set to 0 °, respectively, and preheating is performed at 180 ° C. for 10 minutes without applying press pressure first using a hot press. After that, heat-press for 5 minutes at a pressure of 5 kg / cm ² while maintaining the temperature of 180 ° C., and after integrating them and applying black paint on both the front and back sides, cut out into a predetermined shape and shield the light-shielding blade Manufactured.

(Example 5)
A raw material prepared by mixing 2% by weight of carbon black in Ueno LCP8000 manufactured by Ueno Pharmaceutical was prepared. Then, using Technovel KZW15-30MG2, the cylinder set temperature is 250 ° C, the die set temperature is 270 ° C, the die gap is 0.3mm, the die width is pushed out from the T die with a die width of 120mm. A black LCP film having a thickness of 25 μm and an SOR of 1.46 was obtained.

  On the other hand, a 25 μm thick biaxially stretched black PET film with a matte surface was prepared and sandwiched between the black LCP films, and the crystal orientation directions of these pair of black LCP films were set to 0 °, respectively. Set. Further, an epoxy adhesive mixed with 33% by weight of carbon black was applied between the PET film and the LCP film in a film thickness of about 5 μm, and hot pressing was performed under the same conditions as in Example 1. Were integrated and black paint was applied to both the front and back surfaces, and then cut into a predetermined shape to produce a light shielding blade.

(Comparative Example 1)
A raw material prepared by mixing 2% by weight of carbon black in Ueno LCP8000 manufactured by Ueno Pharmaceutical was prepared. Then, using Technobell KZW15-30MG2, the cylinder set temperature is 250 ° C, the die set temperature is 270 ° C, the die gap is 0.5mm, the die width is pushed out from the T die with 120mm width, A black LCP film with 75 μm and SOR of 1.45 was obtained. And black paint was apply | coated to the front and back both surfaces, it cut out to the predetermined shape, and it was set as the light-shielding blade.

(Comparative Example 2)
A CFRP prepreg with a thickness of 25 μm used as a conventional light-shielding blade (without the addition of a light-shielding agent) is superposed so that the direction of the carbon fiber is 0 ° / 90 ° / 0 °, and a hot press is performed. First of all, pre-heating at 120 ° C. for 10 minutes without applying pressing pressure, then heating to 130 ° C. and hot pressing at a pressure of 5 kg / cm ² for 120 minutes, both sides of the laminated CFRP A black paint was applied to the substrate, and then cut into a predetermined shape to produce a light shielding blade.

(Comparative Example 3)
Carbon black was kneaded with 3% by weight of PET and extruded with a biaxial extruder, and then biaxially stretched to obtain a black PET film having a thickness of 75 μm. And after apply | coating black coating material to the front and back both surfaces, it cut out to the predetermined shape and was set as the light-shielding blade.

  Thus, the light-shielding blades obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were cut into strips of 50 mm along the MD direction and 10 mm along the TD direction of the LCP film located in the outermost layer. Using this as a sample, the film thickness and weight and the flexural modulus were measured. The bending elastic modulus is obtained from the load when both ends of the sample are supported 30 mm apart and a displacement of 4 mm is applied to the center.

  Further, the light-shielding blades obtained in Examples 1 to 5 and Comparative Examples 1 to 3 are incorporated as the front film 11 and the rear film 12 of the focal plane shutter unit 10 shown in FIGS. Evaluation of light leakage when irradiated with light of brightness was performed. Further, an open / close test was conducted 150,000 times at a shutter speed of 1/8000 seconds at normal temperature and humidity, and the durability was also investigated. These results are shown in Table 1.

  In light leakage, “None” indicates that light leakage hardly occurs, and “Yes” in Comparative Example 2 indicates that light leakage frequently occurs. It was confirmed that the light-shielding blade of the present invention has sufficient light-shielding properties due to each LCP film itself, the light-shielding improvement layer between them and the functional layers on both the front and back sides.

  Moreover, in terms of durability, “breakage” in the case of Comparative Example 1 indicates that cracks occurred along the MD direction of the LCP film located in the outermost layer of the light shielding blade at 50,000 times. The “breakage” in the case indicates that the light-shielding blade was damaged after 40,000 times. Regarding this durability, the samples other than the PET single layer of Comparative Example 1 and Comparative Example 3 have no problem with respect to 150,000 open / close tests, and the light-shielding blade of the present invention has a performance equal to or higher than that of the conventional product. Was confirmed.

It is a front view showing the external appearance of one Embodiment which applied the optical path opening / closing apparatus by this invention to the focal plane shutter. It is II-II arrow sectional drawing in FIG. It is a three-dimensional projection figure showing the external appearance of one Embodiment of the light-shielding blade by this invention in a decomposition | disassembly state. It is sectional drawing of the light-shielding blade shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Focal plane shutter unit 11 Lead film 12 Rear film 13-21 Light shielding blade 22 PET film 23, 24 LCP film 25 Functional layer 26 Light shielding improvement layer

Claims (8)

  A thermoplastic resin film other than the liquid crystal polymer, and a plurality of layers of liquid crystal polymer film laminated symmetrically with the thermoplastic resin film interposed therebetween, and the pair of the above-mentioned pair of symmetrically laminated positions with respect to the thermoplastic resin film A light-shielding blade, wherein the crystal orientation directions of the liquid crystal polymer film are parallel to each other or cross each other.   The light-shielding blade according to claim 1, wherein crystal orientation directions of a pair of liquid crystal polymer films located in the outermost layer are parallel to each other. One crystal orientation direction of the tilt angle of the liquid crystal polymer film of pairs located inside the outermost to the crystal orientation of the liquid crystal polymer film of pairs located outermost, the liquid crystal polymer film of pairs located in the outermost layer shielding according to claim 2, characterized in that is tilted by the other of the same angle to the inclination angle and the opposite direction of the crystal orientation direction of the liquid crystal polymer film of pairs located inside the outermost layer against the crystal orientation Feathers. Shielding blade root according to any one of claims 1 to 3, wherein the thermoplastic resin is characterized in that it is a polyester resin.
  The light-shielding property improving layer containing a light-shielding agent is formed between the thermoplastic resin film and the liquid crystal polymer film that overlap each other or between the two liquid crystal polymer films. The light shielding blade according to any one of the above.   The light-shielding blade according to any one of claims 1 to 3, wherein a light-shielding agent is added to the thermoplastic resin film and at least one layer of the liquid crystal polymer film.   The functional layer having at least one of a light shielding property, a lubricating property, and an antistatic property is formed on the surface of the liquid crystal polymer film located in the outermost layer. The light shielding blade according to any one of 6. 8. An optical path opening / closing device using the light shielding blade according to claim 1, wherein a crystal orientation direction of a pair of liquid crystal polymer films is geometrically symmetric with respect to a moving direction of the light shielding blade. An optical path switching device characterized in that the crystal orientation direction of the pair of liquid crystal polymer films located at the outermost layer is substantially orthogonal to the moving direction of the light shielding blade.

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