JPH04345148A - Production of light shielding vane for camera - Google Patents

Abstract

PURPOSE:To reduce the cost of production in the process for forming the light shielding vanes for cameras which are formed by laminating prepreg sheets impregnated with a matrix resin in unidirectionally oriented carbon fibers, then heating and pressurizing the laminated sheets. CONSTITUTION:A resin film 20 coated with a light shieldable and/or lubricative coating material 20a is laminated on at least one surface of a laminate and the laminated sheets and film are simultaneously heated and pressurized at the time of laminating the prepreg sheets 2(3) formed by impregnating the matrix resin 6(8) into the unidirectionally oriented carbon fibers 5(7). Since the resin film 20 coated with such coating material is thereby tightly adhered to the laminate, the stage for separately applying the coating material on the surfaces of the vanes is saved and the cost of the production is reduced. In addition, the direction of the carbon fibers 7 of the prepreg sheets 3 of the intermediate layers is set in the transverse direction of the vanes and Panne family which are inferior in elasticity but are light in weight and inexpensive are used for the carbon fibers 7 by which the cost of production is further reduced and the weight is reduced while the sufficient rigidity is retained.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for manufacturing light shielding blades for cameras, and more specifically, the invention relates to a method for manufacturing light shielding blades for cameras, and more specifically, shutter blades or aperture blades of focal plane shutters or lens shutters of cameras that are required to move at high speed. The present invention relates to a method of manufacturing a light-shielding blade.

0002

[Prior Art] For example, efforts are being made to increase the shutter speed in order to increase the photographic area of focal plane shutters, but with the structure of the light-shielding blades using duralumin plates, there is a limit to thinning in order to maintain rigidity. Yes, the limit is a shutter speed of about 1/4000 seconds. Therefore, in order to achieve higher speeds, blades using carbon fiber-reinforced thermosetting resin sheets that are lightweight and have high specific rigidity are being developed.

[0003] Conventionally, blades using carbon fiber-reinforced thermosetting resin sheets are made by laminating a plurality of unidirectionally reinforced prepregs in which carbon fibers are arranged in one direction so that the directions of the carbon fibers are perpendicular to each other, and then heat-pressing the sheets. The product was produced by solidifying the product, cutting it into the shape of a feather, and coating the surface of the blade with a paint to enhance light-shielding properties and/or lubricity.

0004

[Problems to be Solved by the Invention] Therefore, there are two steps: a step of laminating unidirectionally reinforced prepregs and heat pressing them, a step of cutting them into the shape of a blade, and a step of forming the surface of the blade with light-shielding properties and/or lubrication properties. The problem is that there are many manufacturing steps, it takes time to manufacture, and therefore the manufacturing cost increases.

[0005] Furthermore, since the carbon fiber used as the reinforcing material is expensive, there is also the problem that the manufacturing cost of the light shielding blade increases.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for manufacturing light shielding blades for cameras that can reduce manufacturing costs.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a camera light shielding blade of the present invention involves orienting carbon fibers in one direction and impregnating the carbon fibers with a matrix resin to form a prepreg sheet. A plurality of these prepreg sheets are laminated, and a resin film coated with a paint having light-shielding properties and/or lubricating properties is laminated on at least one surface of the laminate of prepreg sheets, thereby producing a laminated resin film. And the prepreg sheet is heated and pressurized at the same time.

[0008]

[Action] When the laminated resin film and prepreg sheet are heated and pressurized at the same time, the prepreg sheets adhere to each other, and at the same time, the resin film coated with light-shielding and/or lubricating paint adheres to the mutually adhered sheets. This eliminates the need for a separate process of applying a light-shielding and/or lubricating paint.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. ◆One light-shielding blade 1 is shown in FIG. 3, and as shown in FIG. 1, it is composed of two prepreg sheets 2 serving as a surface layer and a prepreg sheet 3 serving as an intermediate layer. The prepreg sheet 2 serving as the surface layer is made of pitch-based carbon fibers 5, which are expensive but have high elasticity, arranged in a thin plate shape in one direction, and then coated with a thermosetting resin such as epoxy or unsaturated polyester. By impregnating the matrix resin 6, a B-stage (semi-cured) sheet having a thickness of, for example, 30 μm is formed.

The prepreg sheet 3 serving as the intermediate layer is made of PAN-based carbon fibers 7, which have poor elasticity but low specific gravity and are inexpensive, aligned in one direction and arranged in a thin plate shape. A matrix resin 8 made of a thermosetting resin such as epoxy or unsaturated polyester is impregnated to form a B-stage sheet having a thickness of, for example, 30 μm. The carbon fibers 7 in the intermediate layer are oriented in the width direction of the blade to strengthen the stiffness in the same direction, and since the stiffness in the same direction is smaller than the stiffness in the longitudinal direction, PAN-based carbon Fiber is also sufficient.

Next, the direction of the carbon fibers 7 of the prepreg sheet 3 that will become the intermediate layer is determined to be perpendicular to the direction of the carbon fibers 5 of the prepreg sheet 2 that will become the two surface layers, and these are laminated. (Figure 1).

Next, as shown in FIG. 2, a paint 20a is prepared in which a black pigment for light-shielding properties and a solid lubricant such as carbon black, molybdenum disulfide, or fluorine for lubrication properties are mixed. A resin film 20 coated with, for example, 5 μm thick is laminated on both outer surfaces of the prepreg sheet laminate. As the resin film 20, a film made of polyphenylene sulfide, polyester, polyimide, etc. and having a thickness of about 5 μm to 10 μm can be used. Note that both thermoplastic and thermosetting resin films can be used as the resin film 20. In the case of thermoplastic, it melts during the heat pressing described below and has good adhesion to the prepreg sheet, and even in the case of thermosetting, the adhesiveness of the prepreg causes the prepreg to melt during the heat pressing described below. Close contact with.

[0013]Then, the laminated resin film and prepreg sheet are heated using a heat press, for example, at a weight of 5 kg/cm.
2. Pressurize at 130°C for 2 hours (not shown). Then, the prepreg sheets and the prepreg sheet and the resin film come into close contact with each other to form a fiber reinforced plastic (FRP) sheet having a thickness of, for example, about 100 μm and having a light-shielding and lubricating paint on its surface.

Then, the blade 1 is positioned so that the direction of the carbon fibers 5 in the surface layer is in the longitudinal direction of the blade 1, and the direction of the carbon fibers 7 in the intermediate layer is in the width direction of the blade 1. Cut out the shape. As a result, the blade 1 shown in FIG. 2 having a light-shielding and lubricating paint on its surface is obtained. The moment of inertia of the blade, which is related to the bending rigidity in the longitudinal direction of the blade, is mainly determined by the carbon fibers 5 of both the upper and lower surface layers, and is therefore sufficiently large, and since the intermediate layer carbon fiber is made of PAN, It is designed to be lightweight.

The blade 1 thus formed is shown in FIG.
As shown in the figure, the holes 1a are attached to the arms 10, 11 by attaching them to the connecting shafts 12, 13, and the other three blades 15, 16, 17 are attached to the arms 9, 10, 11 in the same way.
11. These arms 9, 10, 11
is fixed to the blade receiving plate 19, and the window hole 19a is fixed to the blade 1, 15.
, 16, and 17 to form a shutter. When the rotating portion 18 is rotated by a predetermined means, the blades 1, 15, 16, and 17 are moved in parallel by the parallel crank mechanism to open and close the shutter. The blades are lightweight and highly rigid, and the resin film adheres to their surfaces, making it possible to open and close at high speed without any problems while ensuring the blades' light-shielding and sliding properties. It is.

In this example, the light-shielding and lubricating paints are applied to the blades by laminating a resin film coated with these paints on a laminate of prepreg sheets and simultaneously heating and pressurizing them. Therefore, there is no need to separately provide a coating process for these paints, which simplifies the manufacturing process and reduces manufacturing costs.

In addition, the carbon fibers of the intermediate layer prepreg sheet are oriented in the blade width direction, which requires less reinforcement of rigidity, and inexpensive PAN-based carbon fibers are used for these carbon fibers. Cost reduction is achieved.

In the above embodiment, the resin film 20 was laminated on both sides of the prepreg sheet laminate, but if the resin film is present between the overlapping blades, sliding properties etc. are maintained. It may be laminated on at least one surface of a laminate of prepreg sheets.

Further, in the above embodiment, the prepreg sheets were laminated in three layers, but the present invention is of course applicable to cases in which there are four or more layers.

Further, in the above embodiment, a resin film coated with a paint having light shielding properties and lubricating properties was used, but the present invention uses a resin film coated with a paint having only either light blocking properties or lubricating properties. Of course, it is also applied when laminating a laminate of prepreg sheets.

[0021]

Effects of the Invention The present invention involves laminating a plurality of prepreg sheets, laminating a resin film coated with a light-shielding or lubricating paint on this laminate, and then heating and pressurizing them. Because it is integrated, there is no need to apply paint to the heated and pressurized prepreg sheet as in the past, simplifying the manufacturing process. And it is possible to reduce manufacturing costs.

Furthermore, the surface layer of the prepreg sheet laminate is composed of pitch-based carbon fibers, and the intermediate layer is composed of PAN-based carbon fibers. By arranging them in the same direction, it is possible to reduce weight and cost while maintaining sufficient rigidity.

[Brief explanation of the drawing]

[Figure 1] Enlarged cross-sectional view showing the state in which three prepreg sheets are laminated

[Fig. 2] An enlarged cross-sectional view showing a state in which films coated with light-shielding and lubricating paint are laminated on both outer sides of a prepreg sheet.

[Figure 3] Plan view of the light-shielding blade

[Figure 4] Plan view of focal plane shutter

[Explanation of symbols]

1, 15, 16, 17 Camera light shielding blade 2 Surface layer prepreg sheet 3 Intermediate layer prepreg sheet 5, 7 Carbon fiber 6, 8 Matrix resin 20 Resin film

Claims (2)

[Claims] 1. Orienting carbon fibers in one direction, impregnating the carbon fibers with a matrix resin to produce a prepreg sheet, laminating a plurality of the prepreg sheets, and at least one surface of the laminate of the prepreg sheets. A method for producing a light-shielding blade for a camera, comprising: laminating a resin film coated with a paint having light-shielding properties and/or lubricating properties, and heating and pressurizing the laminated resin film and prepreg sheet at the same time. 2. Among the laminated prepreg sheets, in the surface layer prepreg sheet, the carbon fibers are pitch-based carbon fibers and their orientation direction is the longitudinal direction of the blade, and the intermediate layer is sandwiched between the surface layers. 2. The method for manufacturing a light-shielding blade for a camera according to claim 1, wherein the carbon fibers in the prepreg sheet of the layer are PAN-based carbon fibers, and the direction of orientation thereof is in the width direction of the blade.