JPH10275964A - Flexible printed-circuit board and camera making use of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the reflection of a flexible printed-circuit board in order to prevent a flare, a ghost or the like due to the reflection of leakage light caused by the flexible printed-circuit board used for a signal transmission means in the interior of a camera. SOLUTION: An antireflection layer in which synthetic-resin fine particles in an average particle size of 15 to 50 μm and carbon-black fine particles in an average particle size of 1.0 μm or lower are dispersed into 10 pts.wt. of a synthetic-resin binder such that their ratio is a weight ratio of 1:0 to 1:5 and that their total amount becomes 20 to 500 pts.wt. is formed, or a film, for antireflection, which comprises the antireflection layer is pasted, on a part or the whole of a flexible printed-circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed circuit board for preventing flare and ghost due to reflection of light leakage caused by a flexible printed circuit board used as a signal transmission means inside a camera, and a reflection-prevented flexible printed circuit board. The present invention relates to a camera using a flexible printed board.

[0002]

2. Description of the Related Art In general, various obstacles due to reflection of incident light pose a problem in optical devices such as cameras, copiers and developing machines. For example, in the case of a camera, incident light is reflected on the inner wall to adversely affect the film, or light from a light source is reflected on the inner wall of the camera and enters the finder optical path to make it difficult to view a finder visual field image. In addition, flexible printed circuit boards are used as signal transmission means for driving parts of cameras, copying machines, and the like. Light leakage is reflected on the flexible printed circuit boards, flare is generated, and exposure is performed on a film to be photographed. Adversely affect light, or light enters from the cylindrical portion of the lens portion, and mixes the light from the lens inside the cylinder to cause halation or ghost in the photographed photograph. On the other hand, in a copying machine, when an image is formed on a photoreceptor, light generated from the inside of the copying machine is reflected inside the copying machine, and makes the image on the photoreceptor unclear. Also, in a developing machine, incident light is reflected on an inner wall, and is exposed to a film being developed, or when printing on photographic paper, a photograph becomes out of focus and becomes unclear. I have.

In order to solve such a problem, a photographic lens barrel having a specific length is interlocked between a front surface of an exposure opening of a camera body and a photographic lens barrel moving in an optical axis direction. A camera having a light-shielding means formed on a bellows that expands and contracts (Japanese Patent Laid-Open No. 8-304903) so that the camera can follow the movement of the flexible printed board and move so as to contact the bent end of the flexible printed board. An assembled zoom lens (JP-A-7-63969), and a light-shielding member provided so as to cover at least a part of a shutter blade travel detection unit (JP-A-8-21).
No. 1446) has been proposed. However, these techniques do not provide a satisfactory anti-reflection effect.

[0004]

SUMMARY OF THE INVENTION Under such circumstances, the present invention has been developed to reduce the reflection of a flexible printed circuit board in order to prevent flare and ghost due to the reflection of light leakage caused by a conventional flexible printed circuit board. An object of the present invention is to provide a camera that can effectively prevent the occurrence of flare and ghost.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have applied an antireflection paint having a specific composition onto a flexible printed circuit board,
The object can be achieved by providing an anti-reflection layer or by attaching an anti-reflection film having an anti-reflection layer having a specific thickness formed using the anti-reflection paint to a flexible printed circuit board. This led to the completion of the present invention based on this finding.

That is, the present invention relates to (1) 100 parts by weight of a synthetic resin binder, (A) a weight average particle size of 15 to 50.
μm synthetic resin fine particles and (B) a weight average particle size of 1.0 μm
The following carbon black fine particles are mixed in a weight ratio of 10: 1 to 1: 5, and their total amount is 20 to 500.
A flexible printed circuit board, wherein an antireflection layer dispersed so as to be in parts by weight is provided on a part or the whole surface, and the glossiness of the surface with respect to 60 degrees of incident light is adjusted to 0 to 0.5%; In 100 parts by weight of the synthetic resin binder, (A) synthetic resin fine particles having a weight average particle diameter of 15 to 50 μm and (B) carbon black fine particles having a weight average particle diameter of 1.0 μm or less are used in a weight ratio of 10: 1 to 1: 5. The surface has a gloss of 0 to 60 degrees of incident light and is dispersed in such a manner that the total amount thereof is 20 to 500 parts by weight.
A flexible printed circuit board characterized in that an anti-reflection film having an anti-reflection layer having a thickness of 15 to 100 μm on one surface is attached to a part or the whole surface of the flexible printed circuit board, and 100 parts by weight of a synthetic resin binder. (A) a synthetic resin fine particle having a weight average particle diameter of 15 to 50 μm and (B) a carbon black fine particle having a weight average particle diameter of 1.0 μm or less, in a weight ratio of 1
0: 1 to 1: 5 and their total amount is 2
A flexible printed circuit board having an antireflection layer having a glossiness of 0 to 0.5% with respect to an incident light of 60 degrees on a surface, which is dispersed so as to be 0 to 500 parts by weight, on a part or the entire surface of the substrate, as a signal transmission means. (A) a synthetic resin fine particle having a weight average particle diameter of 15 to 50 μm and (B) a carbon black fine particle having a weight average particle diameter of 1.0 μm or less in 100 parts by weight of a camera and a synthetic resin binder. The surface has a glossiness of 0 to 0.5% at an incident light of 60 degrees and a thickness of 10: 1 to 1: 5, and is dispersed so that the total amount thereof is 20 to 500 parts by weight. An anti-reflection film having an anti-reflection layer having a thickness of 15 to 100 μm on one side is provided on a part or the whole of a flexible printed board, or on a part of a flexible printed board and the inside of a camera. Alternatively there is provided a camera which is characterized in that affixed to both.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The paint used for forming the antireflection layer in the present invention contains a synthetic resin binder, (A) synthetic resin fine particles and (B) carbon black fine particles. As a resin binder,
A curable resin or a thermoplastic resin that is cured by heat or light is used.

In the present invention, among the synthetic resin binders, as the thermosetting resin, for example, an acrylic resin,
Urethane type, phenol type, melamine type, urea type, diallyl phthalate type, polyester type, epoxy type, alkyd type and the like are preferably used. These may be used alone or in combination of two or more. Among these, a thermosetting acrylic resin is particularly preferable because of its excellent heat resistance, moisture resistance, solvent resistance, surface hardness and the like. Examples of the thermoplastic resin include a thermoplastic acrylic resin, a vinyl chloride resin, a butyral resin, and a styrene / butadiene resin.

The synthetic resin binder may contain a crosslinking agent, if desired. Examples of the crosslinking agent include a urea resin, a melamine resin, an isocyanate resin, an aziridine resin, an oxazolidine resin, and the like. Particularly, a melamine resin is preferable because it has excellent heat resistance, solvent resistance, and coating film hardness. The compounding ratio of the crosslinking agent is usually 10 to 50% by weight based on the synthetic resin binder.
Range. If the amount is less than this, desired properties cannot be obtained, and if it is more than this, the coating film is too hard and brittle.
Further, when a crosslinking agent is used, it is desirable to use a reaction catalyst in combination in order to promote the reaction. Examples of the reaction catalyst include ammonia and ammonium chloride. The mixing ratio of the reaction catalyst is usually in the range of 0.1 to 10% by weight based on the crosslinking agent.

Next, examples of the synthetic resin fine particles of the component (A) include fine particles of melamine resin, benzoguanamine resin, benzoguanamine / melamine / formalin condensate, acrylic resin, urethane resin, styrene resin and the like. These may be used alone or in combination of two or more. Among them, acrylic resin is particularly preferable because it can diffusely reflect light on the surface to prevent linear reflection of incident light. The shape of the synthetic resin fine particles is not particularly limited, but is preferably spherical from the viewpoint of improving the flow characteristics of the coating material and providing excellent coating suitability.

The weight average particle size of the synthetic resin fine particles is 15
It needs to be in the range of ５０50 μm. When the weight average particle size is less than 15 μm, the reflectance at a low angle becomes high, and when it exceeds 50 μm, the dispersion stability of the coating material is deteriorated, and the synthetic resin fine particles tend to settle. From the viewpoints of suppression of reflectance at a low angle and dispersion stability of the paint, a particularly preferred weight average particle size of the synthetic resin fine particles is 20 to 40.
It is in the range of μm.

On the other hand, the carbon black fine particles of the component (B) must have a weight average particle diameter of 1 μm or less. When the weight average particle size exceeds 1 μm, the particle difference from the component (A) is reduced, the surface area is reduced, and the packing density of carbon black is reduced, so that the light absorption capacity is reduced and the antireflection property is poor. Become. From the viewpoint of antireflection properties, a particularly preferred weight average particle size of the carbon black fine particles is 0.5 μm or less.

In the present invention, it is necessary that the mixing ratio of the fine synthetic resin particles (A) and the fine carbon black particles (B) is in the range of 10: 1 to 1: 5 by weight. is there. When the proportion of the component (A) is less than the above range, the irregular reflection efficiency of the coating film surface is deteriorated, and the hardness of the coating film is reduced. When the ratio is large, the light absorbency is deteriorated, the degree of blackness is reduced, and the appearance is reduced. Be impaired. In view of the irregular reflection efficiency of the coating film surface, the hardness of the coating film, the appearance, and the like, the particularly preferable mixing ratio of the component (A) and the component (B) is in the range of 5: 1 to 1: 2 by weight.

In the paint used for forming the antireflection layer in the present invention, the total of the components (A) and (B) is 20 parts by weight based on 100 parts by weight of the synthetic resin binder. It is necessary to mix and disperse them in such a ratio that the weight becomes up to 500 weight. When the blending amount is 20
If the amount is less than part by weight, the adhesion to the substrate may be poor, and the reflectance may be high. If the amount is more than 500 parts by weight, the coating film tends to be brittle. From the viewpoint of the properties of the coating film and the antireflection property, the preferable amount of the component (A) and the component (B) is 50 to 2 based on 100 parts by weight of the synthetic resin binder.
It is in the range of 00 parts by weight.

The antireflection coating can be prepared by suspending the synthetic resin binder, the component (A) and the component (B) in water or an organic solvent, or a mixture of water and an organic solvent. At this time, if necessary, various conventionally used additives such as a thickener, a dispersant, a colorant, and an antifoaming agent can be added. In particular, a water-soluble acrylic resin is preferable because it provides an excellent thickening effect and a dispersing effect to the paint. When this water-soluble acrylic resin is blended, the blending ratio is usually 0.1 to the total amount of the synthetic resin binder, the component (A) and the component (B).
It is in the range of 5-5% by weight. 0.5% by weight
If it is less than 5%, the effect of thickening is insufficient, and the effect of improving coating suitability is not sufficiently exhibited. If it exceeds 5% by weight, the liquid viscosity becomes too high, and coating suitability deteriorates.

Next, in the present invention, the antireflection coating is applied to a part or the whole surface of a flexible printed circuit board to form an antireflection layer, or the antireflection coating is applied to one surface of a substrate. To prepare an antireflection film provided with an antireflection layer, and affixed to a part or the entire surface of the flexible printed circuit board so that the back surface thereof is in contact with the film.

At this time, the surface of the antireflection layer formed on a part or the entire surface of the flexible printed circuit board conforms to JIS Z
It is necessary that the glossiness with respect to 60 degrees of incident light when measured by a glossmeter according to 8741 is 0 to 0.5%.
If the gloss exceeds 0.5%, the antireflection effect inside an optical device such as a camera becomes insufficient. The thickness of the antireflection layer is usually in the range of 15 to 100 μm.

On the other hand, when an antireflection film is used, the base material thereof is, for example, paper, synthetic paper, synthetic resin film, or the like. This may be transparent or opaque, but is preferably opaque and has light-shielding properties. In addition, as the synthetic resin film, a film of polyolefin, polyester, polyimide, or the like can be used, and it is preferable that a film in which a black pigment such as carbon black or aniline black is previously kneaded is used. When a synthetic resin film into which a black pigment is kneaded is used, the optical density of the film is 1
It is preferable to use a material having a high light-shielding property of 0 or more. Also, the synthetic resin film can be matted on one side or both sides as needed. The matting can be performed by, for example, a chemical etching method, a sandblasting method, or a chemical matting method comprising a synthetic resin and a roughening forming material. The thickness of the substrate is suitably in the range of 25 to 200 μm. If the thickness is smaller than this, sufficient antireflection properties cannot be obtained, and if the thickness is larger than this, there is a disadvantage in terms of weight reduction.

Next, an anchor layer can be provided on the substrate, if desired, in order to improve the adhesiveness between the substrate and the antireflection layer. The anchor layer is usually made of a urea resin, a melamine resin, a urethane resin, or the like. And, for example, in the case of a urethane-based resin, a solution containing an active hydrogen-containing compound such as a polyisocyanate and a diamine or a diol, and in the case of a urea-based resin or a melamine-based resin, a water-soluble urea-based resin or a water-soluble melamine-based resin Is applied to the surface of the base material and cured to form a layer having a thickness of about 0.5 to 2.0 g / m ² .

In order to manufacture the flexible printed circuit board of the present invention, an antireflection coating containing the above-mentioned synthetic resin binder, component (A) and component (B) on the above-mentioned base material or an optional anchor layer. Is applied to form an antireflection layer. The thickness of this anti-reflection layer is
It needs to be in the range of 15 to 100 μm. If the thickness of the anti-reflection layer is less than 15 μm, the anti-reflection property deteriorates, and if it exceeds 100 μm, the total thickness of the film becomes thick, and the effectiveness in terms of thickness is lost.

The surface of the antireflection layer of the antireflection film must have a gloss of 0 to 0.5% with respect to 60 degrees of incident light when measured with a gloss meter according to JIS Z8741. If the gloss exceeds 0.5%, the antireflection effect inside an optical device such as a camera becomes insufficient. The anti-reflection film has a center line average roughness measured according to JIS B0601 of usually 1.0 to 10.0.
In this case, irregular reflection is performed, whereby an antireflection effect is obtained.

In the antireflection film used in the present invention, a release sheet may be laminated on the surface opposite to the antireflection layer over the entire surface of the substrate and partially with an adhesive layer therebetween. At the time of use, the release sheet is peeled off, and the adhesive sheet can be easily attached to the flexible printed circuit board. The thickness of the adhesive layer is usually 10
２５25 g / m ^2, preferably 12-20 g / m ² .

Examples of the adhesive constituting the adhesive layer include natural rubber, a mixture of natural rubber and styrene-butadiene rubber, an acrylic copolymer, a copolymer of butadiene or isoprene and styrene, a vinyl ether copolymer, and a silicone. Using a rubber or the like as a base material and adding a rosin-based, petroleum-based or terpene-based tackifier to components such as a tackifier, an adhesion improver, an antioxidant, a stabilizer, and a colorant. Among them, a material composed of a base material mainly composed of an acrylate resin is particularly preferable.
Further, in order to prevent reflection based on incident light from the side as much as possible in a cross section or the like, it is advantageous to include a dark colorant.

According to the camera of the present invention, in order to prevent light leaking from the outside of the camera body and the lens member into the camera and reflected on the flexible printed circuit board, the anti-reflection coating is applied to a part or the entire surface of the flexible printed circuit board. Is applied, and the glossiness of the surface with respect to the incident light of 60 degrees is 0 to 0.
It is provided with a 5% antireflection layer.

Further, in order to prevent light leaking from the outside of the camera body and the lens member to the inside of the camera and being reflected on the flexible printed circuit board, another type of camera has the reflective printed circuit formed on a part or the entire surface of the flexible printed circuit board. The anti-reflection film is stuck so that the anti-reflection layer is in contact with light. This anti-reflection film can prevent irregular reflection of light due to light leakage by attaching the anti-reflection film to a part of the flexible printed board and an appropriate place inside the camera. As a method of attaching the anti-reflection film to a flexible printed circuit board or camera, when applying the anti-reflection film, apply an adhesive, or laminate the release sheet in advance with the anti-reflection film via the adhesive layer Then, when applying, peel off the release sheet and attach it to the anti-reflection location, or apply an anti-reflection film to the anti-reflection location with a pressure-sensitive adhesive, and apply the anti-reflection film. You may put on it and stick.

[0026]

In the flexible printed circuit board of the present invention, the anti-reflection layer or the anti-reflection film used for the anti-reflection has excellent light-shielding properties and anti-reflection properties, particularly, anti-reflection properties for light incident at low angles. Therefore, by applying or sticking this antireflection layer or antireflection film on a part or the whole surface of the flexible printed circuit board,
Light leakage is not reflected on the flexible printed circuit board, and no flare or ghost is generated. Therefore, when this is used for a camera, a copying machine, or the like, a clear image free from flare or ghost can be obtained.

[0027]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The physical properties were evaluated according to the following methods. (1) Glossiness (%): Glossiness was measured for incident light at 60, 75, and 85 degrees using a gloss meter according to JIS Z8741. (2) Surface roughness (Ra): Measured as center line average roughness according to JIS B0601. (3) Concentration (visible): Macbath TD
Measured by 904. (4) Camera test: Using a camera using a flexible printed circuit board subjected to an anti-reflection treatment as a signal transmission means, actual shooting was performed while varying the incident angle of sunlight. The degree of reflection of the negative film at that time was visually observed and evaluated as follows. …: No flare, halation or ghost occurred. ×: Flare, halation, and ghost occur.

Example 1 19.5 parts by weight of a thermosetting acrylic emulsion (Movinyl 747, solid content: 43% by weight; manufactured by Hoechst Gosei Co., Ltd.), and carbon black fine particles having an average particle size of 1 μm or less (G
Acrylic resin particles (MBX-30; manufactured by Sekisui Chemical Co., Ltd.) 1 having 38.6 parts by weight of P black # 4613, solid content concentration 12% by weight;
3.5 parts by weight, water-soluble acrylic resin (AC-10H, solid content concentration 20% by weight; Nippon Junyaku Co., Ltd.) 3.6 parts by weight, crosslinking agent (melamine resin, Sumitec Resin M-3, solid content concentration) 80% by weight; 4.5 parts by weight of Sumitomo Chemical Co., Ltd., 4.8 parts by weight of ammonia (5% by weight aqueous solution), 0.9 parts by weight of ammonium chloride (20% by weight aqueous solution), ethanol 10
By weight, 39 parts by weight of water and 39 parts by weight of water were mixed to prepare a coating liquid for forming an antireflection layer.

Next, as a signal transmission means, the antireflection paint was applied to one surface of a flexible printed circuit board present in a zoom lens of a camera to form an antireflection layer. Table 2 shows the physical properties of the thus obtained antireflection layer.
Shown in

Examples 2 and 3 In the coating liquid for forming an anti-reflection layer in Example 1, except that the mixing ratio of each component was changed as shown in Table 1, the coating for forming an anti-reflection layer was performed in the same manner as in Example 1. A working solution was prepared, and an antireflection layer was formed on one surface of the flexible printed circuit board. Table 2 shows the physical properties of the antireflection layer.

Examples 4 to 6 Each of the antireflection paints of Examples 1 to 3 was 100 μm thick.
Is coated on one side of a polyethylene terephthalate film with a wire bar and heated at 130 ° C. for 5 minutes to a thickness of 40
A μm antireflection layer was formed. Table 2 shows the physical properties of the antireflection layer thus obtained.

Comparative Example 1 In Examples 1 and 4, the average particle size of the acrylic resin was 10
An antireflection layer was formed in the same manner as in Example 1 except that the thickness was changed to μm. Table 2 shows the physical properties of this product.

Comparative Examples 2 and 3 An antireflection layer was formed in the same manner as in Examples 1 and 4, except that the coating composition shown in Table 1 was used as the antireflection coating. Table 2 shows the physical properties of this product.

[0034]

[Table 1]

(Note) 1) Thermosetting acrylic emulsion (Movinyl 74)
7, solid content concentration 43% by weight; manufactured by Hoechst Gosei Co., Ltd.) 2) Acrylic resin particles having an average particle diameter of 30 μm (MBX-3
0; manufactured by Sekisui Plastics Co., Ltd.) 3) Fine carbon black particles (G
P black # 4613, solid content concentration 12% by weight; manufactured by Mikuni Pigment Co., Ltd.) 4) Crosslinking agent (melamine resin, Sumitec Resin M-3,
Solid content concentration 80% by weight; manufactured by Sumitomo Chemical Co., Ltd.) 5) Water-soluble acrylic resin (AC-10H, solid content concentration 2)
0% by weight; Nippon Junyaku Co., Ltd.) 6) Ammonia (5% by weight aqueous solution) 7) Ammonium chloride (20% by weight aqueous solution)

[0036]

[Table 2]

As can be seen from Table 2, Comparative Examples 1 to 3 have a high gloss at any angle, or have a low gloss at a high angle but a high gloss at a low angle. On the other hand, in Examples 1 to 6 of the present invention, the glossiness at low and high angles is low, and no flare, halation or ghost occurs during actual shooting.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Yamamoto 4-11-2 Ginza, Chuo-ku, Tokyo Inside Somar Co., Ltd.

Claims (4)

[Claims] A weight ratio of (A) synthetic resin fine particles of 15 to 50 μm and (B) carbon black fine particles of 1.0 μm or less in 100 parts by weight of a synthetic resin binder is 10: 1. And an antireflection layer dispersed at a ratio of 1: 5 and a total amount of 20 to 500 parts by weight is provided on a part or the entire surface, and the glossiness with respect to incident light of 60 degrees on the surface is reduced to 0. A flexible printed circuit board characterized by being adjusted to 0.5%. 2. A synthetic resin binder (100 parts by weight) contains (A) synthetic resin fine particles having a weight average particle diameter of 15 to 50 μm and (B) carbon black fine particles having a weight average particle diameter of 1.0 μm or less at a weight ratio of 10: 1. And a surface having a gloss of 0 to 60 degrees of incident light having a gloss of 0 to 1: 5 and dispersed so that the total amount thereof is 20 to 500 parts by weight.
A flexible printed board, characterized in that an antireflection film having an antireflection layer of 0.5% and a thickness of 15 to 100 μm on one surface is affixed to a part or the whole surface. 3. A synthetic resin binder having 100 parts by weight of (A) synthetic resin fine particles having a weight average particle diameter of 15 to 50 μm and (B) carbon black fine particles having a weight average particle diameter of 1.0 μm or less has a weight ratio of 10: 1. And a surface having a gloss of 0 to 60 degrees of incident light having a gloss of 0 to 1: 5 and dispersed so that the total amount thereof is 20 to 500 parts by weight.
A camera using a flexible printed circuit board having a 0.5% anti-reflection layer on a part or the entire surface of the circuit board as a signal transmitting means. 4. A synthetic resin binder having 100 parts by weight of (A) synthetic resin fine particles having a weight average particle size of 15 to 50 μm and (B) carbon black fine particles having a weight average particle size of 1.0 μm or less has a weight ratio of 10: 1. And a surface having a gloss of 0 to 60 degrees of incident light having a gloss of 0 to 1: 5 and dispersed so that the total amount thereof is 20 to 500 parts by weight.
0.5%, an anti-reflection film having an anti-reflection layer having a thickness of 15 to 100 μm on one surface is provided on a part or the whole of a flexible printed board, or a part of a flexible printed board and the inside of a camera, or A camera characterized by being attached to both.