JPH09297256A - Camera lens barrel and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a camera lens barrel which has good moldability, excellent mechanical characteristics, such as strength and excellent dimensional accuracy, such as circularity of molded products, and is made of a lightweight resin by molding camera lens barrel bodies with the liquid crystalline resins. SOLUTION: A first lens group 2 is fixed to a focusing lens barrel 1 and is screwed to the screw threads of a lens barrel body 3. A cam frame 4 is freely turnably fitted to the inner side of the lens barrel body 3. A rear lens barrel 11 is connected to the lens barrel body 3 to fix a third lens group 12. The focusing lens barrel 1, the lens barrel body 3, the rear lens barrel 11 and the cam frame 4 respectively correspond to the camera lens barrel. These camera lens barrel bodies are molded of liquid crystalline resins. The liquid crystalline resins are resins which can form an anisotropic molten phase in melting and are preferably polyester and/or polyester amide and are further preferably selected from fully arom. liquid crystalline polyester, fully arom. liquid crystalline polyester amide, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to moldability, mechanical properties,
The present invention relates to a camera barrel having excellent dimensional accuracy and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, an autofocus function or a zoom function like a VTR camera has been incorporated into a camera mechanism, and therefore, many lens groups are housed in a lens barrel and the resolution is high. The camera barrel is usually made of metal such as aluminum, but it has also been attempted to construct it from plastic.
For example, Japanese Unexamined Patent Publication No. 1-259039 proposes to manufacture a lens barrel body from a polycarbonate resin or a polyphenylene oxide resin containing a specific glass fiber.

[0003]

However, the aluminum lens barrel has various problems that it is easily rusted, its productivity is poor due to poor moldability, and that it is heavy. The camera barrel described in Japanese Patent Laid-Open No. 1-259039 is intended to improve such a defect. However, in the case of a polycarbonate resin or a polyphenylene oxide resin, the roundness of the molded product and the dimensional accuracy of the screw shape are improved. In addition to being defective, there is a drawback that it is difficult to deform due to lack of rigidity, and it is difficult to rotate with a small clearance because the coefficient of thermal expansion is greatly different from the lens, and it is quite useful for practical use. There's a problem.

An object of the present invention is to solve the above-mentioned conventional problems, to provide a light-weight resin having good moldability, excellent mechanical properties such as strength, and excellent dimensional accuracy such as roundness of a molded product. To provide a camera barrel and a manufacturing method thereof.

[0005]

The camera barrel of the present invention comprises:
The lens barrel body is formed of a liquid crystalline resin. The camera barrel manufacturing method according to the present invention is characterized in that the lens barrel body is molded from a liquid crystalline resin.

[0006]

1 is a vertical sectional view showing a lens barrel portion of a VTR camera according to an embodiment of the present invention with a lens incorporated therein. The first lens group 2 is fixed to the focus lens barrel 1 at the front end, the rear end is threaded, and is screwed into the screw of the main body barrel 3. A cam frame 4 is rotatably fitted inside the main body barrel 3, and the cam frame 4
A second group moving frame 6 and a third group moving frame 7 are fixed to the cam follower 5 fixed to. The second lens group 8 is fixed to the second group moving frame 6, and the correction lens 9 is fixed to the third group moving frame 7. Reference numeral 10 denotes a fixed lens fixed to the main body barrel 3. A rear lens barrel 11 is connected to the rear end of the main lens barrel 3 to fix the third lens group 12.

In the barrel of the VTR camera, the focus lens barrel 1, the main barrel 3, the rear barrel 11, and the cam frame 4 correspond to the camera barrel of the present invention. In the present invention, all of these lens barrels or frames may be made of liquid crystalline resin, or some of them may be made of liquid crystalline resin. The camera barrel of the present invention is suitable for the above-mentioned VTR camera, but it can be applied to a lens barrel of a camera for photography and other camera devices having a similar mechanism.

The liquid crystalline resin used for molding the body of the camera barrel of the present invention will be described below. The liquid crystalline resin in the present invention is a resin capable of forming an anisotropic molten phase at the time of melting, and is preferably polyester and / or polyesteramide, and further, wholly aromatic liquid crystalline polyester, wholly aromatic liquid crystalline polyesteramide, It is preferably selected from liquid crystalline polyesters having an ethylenedioxy unit and liquid crystalline polyesteramides having an ethylenedioxy unit.

For example, specifically, a liquid crystalline polyester having a wholly aromatic group, preferably a naphthalene ring, a liquid crystalline polyesteramide having a wholly aromatic group, preferably a naphthalene ring, a liquid crystalline polyester having an ethylene dioxide unit, ethylene. It is a liquid crystalline polyesteramide having a dioxy unit. Preferred examples of the liquid crystalline polyester include a liquid crystalline polyester composed of the following structural units (I), (III) and (IV), a liquid crystalline polyester composed of the structural units (I), (II) and (IV), Or (I),
A liquid crystalline polyester composed of structural units (II), (III) and (IV) can be mentioned.

[0010]

Embedded image (However, R ₁ in the formula is

[0011]

[Chemical 6] It represents one or more groups selected from, R ₂ is

[0012]

[Chemical 7] And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural units (II) and (III)
And the structural unit (IV) are substantially equimolar. )

The above structural unit (I) is a structural unit of polyester produced from p-hydroxybenzoic acid, and (I)
I) is 4,4'-dihydroxybiphenyl, 3,3 ',
5,5'-tetramethyl-4,4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone,
Structural unit formed from an aromatic dihydroxy compound selected from phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane and 4,4'-dihydroxydiphenyl ether The structural unit (II
I) is a structural unit produced from ethylene glycol, and structural unit (IV) is terephthalic acid, isophthalic acid, 4,4'-
Diphenyldicarboxylic acid, 2,6'-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4 '
A structural unit formed from an aromatic dicarboxylic acid selected from dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid. R of these
₁ is

[0014]

Embedded image And R ₂ is

[0015]

Embedded image Is particularly preferred. Further, as the liquid crystalline polyesteramide, in addition to the above structural units (I) to (IV), p-
Polyesteramides which form an anisotropic melt phase containing p-iminophenoxy units formed from aminophenol are preferred.

The liquid crystalline polyester which can be preferably used in the present invention is the above-mentioned structural unit (I), (II) and (IV) or a copolymer comprising (I), (II), (III) and (IV). And the copolymerization amount of the structural units (I), (II), (III) and (IV) is arbitrary. However, the following copolymerization amount is preferred from the viewpoint of fluidity. That is, the above structural unit (II
In the case of containing I), the total of the structural units (I) and (II) is (I), from the viewpoint of heat resistance, flame retardancy and mechanical properties.
The total amount of (II) and (III) is preferably 60 to 95 mol%, more preferably 75 to 93 mol%. The structural unit (III) is 40 to 5 in total of (I), (II) and (III).
Mol% is preferable, and 25 to 7 mol% is more preferable. Further, the molar ratio of the structural units (I) and (II) [(I) / (I
I)] is preferably 75/25 to 95/5, more preferably 78/2 from the viewpoint of the balance between heat resistance and fluidity.
2 to 93/7. Further, the structural unit (IV) is substantially equimolar to the total of the structural units (II) and (III).

On the other hand, when the structural unit (III) is not contained, the structural unit (I) is preferably 40 to 90 mol% of the total of (I) and (II) from the viewpoint of fluidity, It is particularly preferably 60 to 88 mol%, and the structural unit (IV) is substantially equimolar to the structural unit (II).
Further, the liquid crystalline polyester resin used in the present invention preferably has a crystal heat of fusion of 1.5 J / g or more as measured by differential calorimetry.

It is preferable that the melting point (Tm, ° C) satisfies the following formula (1) and the logarithmic viscosity is 1.0 to 3.0 dl / g. −10 <Tm−0.769x ² + 8.20x−401.5 <10 (1) (where x in the formula (1) is (I) of the structural unit (III),
The ratio (mol%) to the total of (II) and (III) is shown. ) When polycondensing the above liquid crystalline polyester preferably used in the present invention, the above structural units (I) to (IV)
In addition to the components constituting the above, aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid and 2,2′-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanedioic acid, Alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, methylhydroquinone, 4,4'-
Aromatic diols such as dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol Aliphatic and alicyclic diols such as 1,4-cyclohexanedimethanol and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and p-aminophenol and p-aminobenzoic acid Can be further copolymerized in a small proportion.

For example, in the production of the above-mentioned preferably used liquid crystalline polyester, the following (1) and (2) are used when the structural unit (III) is not contained, and (3) when the structural unit (III) is contained. A manufacturing method is preferably mentioned. (1) Deacetic acid polycondensation reaction of p-acetoxybenzoic acid and diacylated aromatic dihydroxy compounds such as 4,4′-diacetoxybiphenyl and 4,4′-diacetoxybenzene with aromatic dicarboxylic acids such as terephthalic acid How to manufacture by.

(2) p-hydroxybenzoic acid and 4,
A method in which an aromatic dihydroxy compound such as 4'-hydroxybiphenylhydroquinone and an aromatic dicarboxylic acid such as terephthalic acid are reacted with acetic anhydride to acylate a phenolic hydroxyl group, and then a deacetic acid polycondensation reaction is carried out. (3) by the method of (1) or (2) in the presence of a polyester polymer such as polyethylene terephthalate, an oligomer, or a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid such as bis (β-hydroxyethyl) terephthalate. Method of manufacturing.

These polycondensation reactions proceed without a catalyst, but when it is preferable to add stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, metal compounds such as magnesium metal, etc. is there. Some of the liquid crystalline resins of the present invention are capable of measuring logarithmic viscosity in pentafluorophenol, in which case the value measured at 60 ° C. at a concentration of 0.1 g / dl is 0.5 dl / g. The above is preferable, and particularly when the structural unit (III) is included, 1.0 to 3.0 dl / g is preferable,
2.0 to 10.0 when the structural unit (III) is not included
dl / g is preferred.

The melt viscosity of the liquid crystalline resin in the present invention is preferably 1 to 2000 Pa · s, and particularly 2 to 100 Pa.s.
0 Pa · s is more preferable. Here, the melt viscosity is a value measured by a high-pressure capillary viscometer using a capillary having a diameter of 1 mm and a length (l) ≧ 5 mm under the condition of melting point + 10 ° C. and shear rate of 1000 / sec. Further, the melting point is the endothermic peak temperature (Tm) observed when the resin is measured from room temperature under a temperature rising condition of 20 ° C./min in the differential calorimetric measurement.
After the observation of 1), the temperature was kept at Tml + 20 ° C. for 5 minutes, then once cooled to room temperature under a temperature lowering condition of 20 ° C./minute,
The endothermic peak temperature (Tm2) observed when measured again under the temperature rising condition of 20 ° C./min.

The liquid crystalline resin in the present invention may contain a filler. The filler is not particularly limited, for example, glass fiber, carbon fiber, aramid fiber, potassium titanate fiber, silica, talc, clay,
Examples thereof include mica, glass beads, bentonite, calcium carbonate, calcium oxide, alumina, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide and hydrotalcite, and among them, glass fiber is preferable. The glass fiber is preferably treated with a silane coupling agent or the like.

The amount of the filler compounded is preferably 5 to 300 parts by weight, more preferably 10 to 200 parts by weight, based on 100 parts by weight of the liquid crystalline resin. In the present invention, carbon black can be further blended, and the carbon black that can be used is not particularly limited, but the pH is 3 to 3 from the viewpoint of mechanical properties of the obtained composition.
10 is preferable, and one having a pH of 5 to 9 is particularly preferable. The blending amount of carbon black is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the liquid crystal resin.

In the present invention, an olefin polymer may be further added. Examples of the olefin polymer include polyethylene, polypropylene, a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, a copolymer of propylene and an α-olefin having 4 or more carbon atoms, and ethylene and 3 carbon atoms. It is one or more selected from the above-mentioned copolymers composed of α-olefins and non-conjugated dienes.

The α-olefin having 3 or more carbon atoms is preferably propylene, butene-1, pentene-.
1,3-methylpentene-1, octacene-1, etc. are more preferable, and propylene and butene-1 are more preferable, and these can be used in combination of two or more kinds. Α with 4 or more carbon atoms
Examples of the olefin include α-olefins having 3 or more carbon atoms, excluding propylene, and these can be used in combination of two or more kinds.

The non-conjugated diene is preferably 5-ethylidene-2-norbornene, dicyclopentadiene,
1,4-hexadiene and the like can be used. The copolymerization ratio of ethylene and the α-olefin having 3 or more carbon atoms is usually 40/60 to 99/1 (molar ratio), preferably 70 in the copolymer comprising ethylene and the α-olefin having 3 or more carbon atoms. / 30 to 95/5 (molar ratio).

The copolymerization amount of ethylene in the copolymer consisting of ethylene, an α-olefin having 3 or more carbon atoms and a non-conjugated diene is usually 5 to 96.9 mol%, preferably 30 to 84.5 mol%. The copolymerization amount of the α-olefin having 3 or more carbon atoms is usually 3 to 80 mol%, preferably 15 to 60 mol%, and the copolymerization amount of the non-conjugated diene is usually 0.1. -15 mol%, preferably 0.5-1
0 mol%. The copolymerization amount of propylene in the copolymer of propylene and an α-olefin having 4 or more carbon atoms and a non-conjugated diene is usually 5 to 96.9 mol%, preferably 30 to 84.5 mol%. The copolymerization amount of the α-olefin having 3 or more carbon atoms is usually 3 to 80 mol%, preferably 15 to 60 mol%, and the copolymerization amount of the non-conjugated diene is usually 0.1 to 15 mol%. , Preferably 0.5 to 10 mol%.

Specific examples of these copolymers include ethylene / propylene copolymers, ethylene / butene-1 copolymers, ethylene / pentene-1 copolymers, ethylene / propylene / butene-1 copolymers, propylene. / Penten-
1 copolymer, propylene / butene-1 copolymer, ethylene / propylene / 5-ethylidene-2-norbornene copolymer, ethylene / propylene / 1,4-hexadiene copolymer, propylene / butene-1 / 1 It is a 4-hexadiene copolymer, an ethylene / propylene / dicyclopentadiene copolymer, and the like. Among them, an ethylene / propylene copolymer and an ethylene / butene-1 copolymer are more preferable because of excellent heat resistance.

The above olefin polymers may be used in combination of two or more kinds. Further, these olefin-based polymers, from the viewpoint of fluidity of the resulting composition, an epoxy group,
It is preferable that a monomer containing a carboxylic acid group or the like is not copolymerized. The weight average molecular weight of the olefin polymer is 10,000 to 600,000, preferably 30,000 to 500,000, and more preferably 10.
It is preferably in the range of 50,000 to 450,000. Here, the weight average molecular weight can be measured by a gel permeation chromatograph (GPC) method. Using o-dichlorobenzene as a typical solvent, the molecular weight can be measured based on monodisperse polystyrene having a known molecular weight.

The amount of the above-mentioned olefin polymer added is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the liquid crystalline resin. In the present invention, a liquid crystal resin may be further blended with a flame retardant, and as the flame retardant which can be used, a known organic bromine compound is contained, and a bromine content of 20% by weight or more is particularly preferable.

Specifically, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis (pentabromophenoxy) ethane, ethylene Bis (tetrabromophthalimide), a polycarbonate oligomer produced from tetrabromobisphenol A as a raw material, a copolymer thereof with bisphenol, a brominated epoxy compound (for example, a monoepoxy compound obtained by a reaction of brominated bisphenol A and epichlorohydrin) , Poly (brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A cyanuric and brominated phenol Compounds, halogenated polymers and oligomers such as brominated polystyrene, crosslinked brominated polystyrene, and crosslinked brominated poly α-methylstyrene, and mixtures thereof. Among them, ethylene bis (tetrabromophthalimide), brominated epoxy Oligomer or polymer, brominated polystyrene, crosslinked brominated polystyrene, brominated polyphenylene ether and brominated polycarbonate are preferred, with brominated polystyrene being most preferred.

As the brominated polystyrene, brominated polystyrene and crosslinked brominated polystyrene produced by brominating polystyrene obtained by radical polymerization or anionic polymerization, or radical polymerization or anion polymerization of brominated styrene monomer, Preferable examples include polybrominated styrene produced by radical polymerization, and polybrominated styrene produced from brominated styrene monomer is particularly preferable.

The brominated styrene monomer referred to here is styrene.
2 to 3 bromine sources per aromatic ring
Those introduced by a substitution reaction are preferable,
Monobrominated in addition to styrene and / or tribrominated styrene
It may contain styrene and the like. Polybrominated steel
Ren is dibrominated styrene and / or tribrominated styrene
It is preferable that the content is 60% by weight or more, 70
It is more preferable that the content is at least wt%. Dibromination
In addition to styrene and / or tribrominated styrene, monobrominated
40% by weight or less of thylene, preferably 30% by weight or less
It may be polymerized polybrominated styrene. This poly
The weight average molecular weight of brominated styrene is 1 × 10. ^Four~ 15x
10^FourIs more preferred. The weight average molecular weight is
Value measured using a permeation chromatograph (GPC)
As a typical solvent, tetrahydrofuran (TH
F) is used, and the standard is monodisperse polystyrene of known molecular weight
And the molecular weight was measured.

As the crosslinked brominated polystyrene, polystyrene obtained by brominated porous polystyrene crosslinked with divinylbenzene is preferable. The amount of the organic bromide compounded is preferably 0.5 to 60 parts by weight, particularly 1 to 30 parts by weight, per 100 parts by weight of the liquid crystalline resin. Further, in the liquid crystalline resin molded product of the present invention, the organic bromide is preferably dispersed in the resin composition before molding with an average diameter of 25 μm or less, and more preferably 2.0 μm or less. This dispersion diameter can be determined by cutting the resin composition into flakes and averaging the equivalent diameters of 100 particles using a transmission electron microscope (TEM).

In the resin composition of the present invention, if necessary,
An amount of the thermoplastic resin, which does not impair the object of the present invention,
Additives can be added. The camera barrel of the present invention is molded by an injection molding method. As a preferable injection molding method, for example, the resin is supplied to an in-line type injection molding machine in which the melting point of the liquid crystalline resin is set to 30 ° C. to + 50 ° C. It is recommended to use a method of injection molding into a mold of a molded product in which the mold temperature is set to a temperature condition of about 70 ° C to 150 ° C.

[0037]

【Example】

Synthesis Example 1 994.5 parts by weight of p-hydroxybenzoic acid, 125.7 parts by weight of 4,4′-dihydroxybiphenyl, 117.7 parts by weight of terephthalic acid, and intrinsic viscosity were placed in a reaction vessel equipped with a distillation tube and a stirring blade. 216.2 parts by weight of polyethylene terephthalate of about 0.6 and 960.2 parts by weight of acetic anhydride were charged, and deacetic acid polymerization was carried out under the following conditions.

First, after reacting in a nitrogen atmosphere at 130 to 150 ° C. for 4 hours, the temperature was raised to 250 ° C. over 2.5 hours, and the reaction was continued at 250 ° C. for 2.5 hours. Furthermore, after raising the temperature in the system to 320 ° C. over 2 hours, the pressure in the system was reduced to 0.3 mmHg in 1.5 hours, and the reaction was continued for another 30 minutes to complete the polycondensation. As a result of the above reaction, a beige liquid crystalline polyester resin (A-1) was obtained.

The melting point of this polymer was measured using a Perkin-Elmer DSC-7 model at a temperature rising rate of 20 ° C./min. As a result, Tm was 314 ° C., and the heat of crystal fusion was 2.3.
It was J / g. The liquid crystal starting temperature of this polymer is 2
95 ° C. The logarithmic viscosity of this polymer was 1.8.
dl / g, melt viscosity 324 ° C, shear rate 1000
The fluidity was extremely good at (1 / sec) of 52 Pa · s.

Synthetic Example 2 994.5 parts by weight of p-hydroxybenzoic acid, 501.1 parts by weight of 6-hydroxy-2-naphthoic acid, and 1108 parts by weight of acetic anhydride were charged, and the same method as in Synthetic Example 1 was repeated.
As a result of heating up to 30 ° C. and conducting a deacetic acid polymerization reaction, a beige liquid crystalline polyester resin (A-2) was obtained.

The Tm of this polymer was 280 ° C., the heat of crystal fusion was 1.1 J / g, and the onset temperature of the liquid crystal of this polymer was 2
It was 65 ° C. The logarithmic viscosity of this polymer was 5.5.
dl / g, melt viscosity 290 ° C, shear rate 1000
(1 / second) was 53 Pa · s. Synthesis Example 3 1297 parts by weight of p-acetoxybenzoic acid and 345.9 parts by weight of polyethylene terephthalate having an intrinsic viscosity of about 0.6 were charged, and the temperature was raised to 300 ° C. in the same manner as in Synthesis Example 1 to carry out a deacetic acid polymerization reaction. As a result, a beige liquid crystalline polyester resin (A-3) was obtained.

The Tm of this polymer is 284 ° C., the heat of fusion of crystal is 0.8 J / g, and the liquid crystal starting temperature of this polymer is 2
It was 65 ° C. The logarithmic viscosity of this polymer is 0.7.
dl / g, melt viscosity 294 ° C, shear rate 1000
(1 / second) was 50 Pa · s. Examples 1 to 3 and Comparative Examples 1 to 3 30 parts by weight of glass fibers were melt-kneaded with 70 parts by weight of each of the resins A-1 to A-6, and the roundness described below was obtained for each resin composition. And the rigidity was measured. Table 1 shows the results.

A-1: Liquid crystal polyester resin produced in Synthesis Example 1 A-2: Liquid crystal polyester resin produced in Synthesis Example 2 A-3: Liquid crystal polyester resin produced in Synthesis Example 3 A-4: "Torelina" M2588 (Toray PPS resin) A-5: "Toray PBT resin" 1200S (Toray PB)
T resin) A-6: "Iupilon" S-3000 (PC resin manufactured by Mitsubishi Engineering Plastics Co., Ltd.)-[Roundness] The resin temperature is Tm + 10 ° C (A-6 is 290).
C.) and a mold temperature of 90.degree. C., injection molding was performed to obtain a camera barrel having an outer diameter of 35 mm, a length of 25 mm, and a wall thickness of 1 mm, and the roundness of the lens fitting portion (end portion) was measured.

The roundness was evaluated by measuring the diameter of the lens fitting portion using a precision roundness measuring instrument (manufactured by Tokyo Seimitsu Co., Ltd.) and determining the difference between the longest diameter and the smallest diameter. The smaller the difference between the longest diameter and the smallest diameter, the better the roundness.・ [Rigidity] Length 125 injection molded under the same conditions as above
Bending elastic modulus was measured by performing a bending test with a span of 20 mm and a strain rate of 0.7 mm / min using a test piece of mm, width 12 mm, and thickness 1 mm.

[0045]

[Table 1] Examples 4-6, Comparative Examples 4-6 35 parts by weight of glass fiber and 15 parts by weight of mica were melt-kneaded with 50 parts by weight of each of the resins A-1 to A-6, and each resin composition was obtained. The roundness and the rigidity described above were measured. The results are shown in Table 2.

[0046]

[Table 2]

[0047]

As described above, in the camera barrel of the present invention, since the lens barrel main body is molded of liquid crystal resin, it has excellent mechanical properties such as strength and excellent dimensional accuracy such as roundness. Can be Further, in the production method of the present invention, excellent moldability can be obtained by using the liquid crystalline resin.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a lens barrel portion of a VTR camera incorporating a lens according to an embodiment of the present invention.

[Explanation of symbols]

 1 Focus lens barrel 3 Main barrel 4 Cam frame 6 2nd group moving frame 7 3rd group moving frame 11 Rear lens barrel

Claims (9)

[Claims] 1. A camera barrel in which a barrel body is formed of a liquid crystalline resin. 2. The camera barrel according to claim 1, wherein the molding is injection molding. 3. The camera barrel according to claim 1, wherein the liquid crystalline resin is a liquid crystalline polyester resin. 4. The camera barrel according to claim 3, wherein the heat of crystal fusion of the liquid crystalline polyester resin measured by a differential calorific value is 1.5 J / g or more. 5. The liquid crystalline polyester resin, wherein the liquid crystalline polyester resin comprises the following structural units (I), (III) and (IV), and the liquid crystal comprising structural units (I), (II) and (IV) The camera barrel according to claim 3, wherein the camera barrel is at least one selected from the group consisting of a liquid crystalline polyester and a liquid crystalline polyester composed of structural units (I), (II), (III) and (IV). Embedded image (However, R ₁ in the formula is And R ₂ represents one or more groups selected from And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural units (II) and (III)
And the structural unit (IV) are substantially equimolar. ) 6. R ₁ and R _{2 in} the structural units (II) and (IV) of the liquid crystalline polyester resin are as follows: And the total of the structural units (I) and (II) is (I),
60 to 95 mol% of the total of (II) and (III), and the structural unit (III) is 40 to the total of (I), (II) and (III).
5 mol%, molar ratio of structural units (I) and (II) [(I) /
(II)] is 75/25 to 93/7 and has a melting point (T
m, ° C) satisfies the following formula (1) and the logarithmic viscosity is 1.0 to
The camera barrel according to claim 5, wherein the camera barrel has 3.0 dl / g. −10 <Tm−0.769x ² + 8.20x−401.5 <10 (1) where x in the formula (1) is (I) of the structural unit (III),
The ratio (mol%) to the total of (II) and (III) is shown. 7. The camera barrel according to claim 1, wherein the liquid crystalline resin contains a filler. 8. The camera barrel according to claim 1, wherein the liquid crystalline resin contains a flame retardant. 9. A method of manufacturing a camera barrel, wherein a barrel body is molded from a liquid crystalline resin.