Abstract: A golf ball 2 has, on a surface thereof, a plurality of types of dimples 8 having different diameters from each other. The standard deviation of the curvature radii of cross sections of all the dimples 8 is 0.90 mm or less. The average of the curvature radii of the cross sections of all the dimples 8 is greater than 40% but 50% or less of the diameter of the golf ball 2. The sum of the volumes of all the dimples 8 is 280 mm3 or greater but 350 mm3 or less. The average of the diameters of all the dimples 8 is 3.9 mm or greater but 4.5 mm or less. The ratio of the sum of the areas of all the dimples 8 to the surface area of a phantom sphere of the golf ball 2 is 75% or greater but 95% or less.

Abstract: A golf ball 2 includes a core 4, an envelope layer 6, a mid layer 8 and a cover 10. A thickness Tm of the mid layer 8 is less than 1.2 mm. A thickness Tc of the cover 10 is less than 0.6 mm. The sum of the thicknesses Tm and Tc is equal to or less than mm. A hardness Hs of the envelope layer 6 is 50 or greater. A hardness Hm of the mid layer 8 is 30 or greater and 60 or less. A hardness Hc of the cover 10 is less than 40. The hardness Hs, the hardness Hm, and the hardness Hc satisfy the following formula (1). Hs?Hm?Hc??(1) The base material of the envelope layer 6 is ionomer resin. The base material of the midlayer 8 is polyurethane. The base material of the cover 10 is polyurethane.

Abstract: A golf ball 2 includes a core 4, an envelope layer 6positioned outside the core 4, a mid layer 8 positioned outside the envelope layer 6, and a cover 10 positioned outside the mid layer 8. The core 4 includes a spherical center 12 and a core outer layer 14 positioned outside the center 12. The center 12 has a diameter of 1 mm or greater and 15 mm or less. The difference (H4?H3) between the JIS-C hardness H4 of the core 4 at its surface and the JIS-C hardness H3 of the core outer layer 14 at its innermost portion is equal to or greater than 10. The cover 10 has a Shore D hardness H7 less than 40. The Shore D hardnesses H5, H6 and H7 of the envelope layer 6, the mid layer 8, and the cover 10 satisfy that H5>H6?H7.

Abstract: An object of the present invention is to provide a golf ball which has excellent durability and wear-resistance and provides an excellent shot feeling. The present invention is directed to a golf ball comprising: a core; and a cover covering the core, wherein the cover is formed from a cover composition containing a thermoplastic polyurethane (A), a polyisocyanate (B) having at least two isocyanate groups, and a polyhydroxyether (C) as a resin component, and wherein the core has a surface hardness of 85 or smaller in JIS-C hardness.

Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 positioned outside the core 4. The golf ball 2 further has dimples 8 on a surface thereof. The core 4 is obtained by crosslinking a rubber composition. The difference between a hardness H(5.0) at a point that is located at a distance of 5 mm from the central point of the core 4, and a hardness Ho at the central point is equal to or greater than 6.0. The difference between a hardness H (12.5) at a point that is located at a distance of 12.5 mm from the central point, and the hardness H(5.0) is equal to or less than 4.0. The difference between a hardness Hs at the surface of the core 4 and the hardness H(12.5) is equal to or greater than 10.0. The difference between the hardness Hs and the hardness Ho is equal to or greater than 22.0. There is no zone in which a hardness decreases from the central point to the surface. The rubber composition of the core 4 includes 2-naphthalenethiol. A cross-sectional shape of each dimple 8 is a wave-like curve.

Abstract: A modulation method according to the invention is applied to a modulation device in which a light source is driven by a differential signal while a modulation circuit and the light source are capacitively coupled. In the modulation method of the invention, when an average potential fluctuates at an input terminal of the light source, a potential fluctuation is externally provided using a control circuit such that a normal phase side and a reverse phase side become equal to each other in a time constant of the fluctuation in average potential, and transient states of the average potentials at the normal phase side and reverse phase side are equalized and cancel each other as in-phase components of a signal input to the light source, which allows an optical signal to be normally transmitted from the light source.

Abstract: A golf ball 2 includes a spherical core 4, a mid layer 6, and a cover 8. The core 4 is obtained by crosslinking a rubber composition. The difference between: a hardness H(5.0) at a point which is located at a distance of 5 mm from the central point of the core 4; and a hardness Ho at the central point is 6.0 or greater. The difference between: a hardness H(12.5) at a point which is located at a distance of 12.5 mm from the central point; and the hardness H(5.0) is 4.0 or less. The difference between a hardness Hs at the surface of the core 4 and the hardness H(12.5) is 10.0 or greater. The difference between the hardness Hs and the hardness Ho is 22.0 or greater. There is no zone in which a hardness decreases from the central point to the surface. A Shore D hardness H3 of the cover is greater than a Shore D hardness H2 of the mid layer.

Abstract: At all points Pa in a zone A extending over a distance range from equal to or greater than 1 mm to less than 5 mm from the central point of a core 4, a mathematical formula, Ha2?Ha1<5, is satisfied. At any of points Pb in a zone B extending over a distance range from equal to or greater than 5 mm to equal to or less than 10 mm from the central point of the core 4, a mathematical formula, Hb2?Hb1?5, is satisfied. Ha1 and Ha2 indicate JIS-C hardnesses at points Pa1 and Pa2 located radially inward and outward of each point Pa at a distance of 1 mm from the point Pa. Hb1 and Hb2 indicate JIS-C hardnesses at points Pb1 and Pb2 located radially inward and outward of the point Pb at a distance of 1 mm from the point Pb.

Abstract: In the present invention, unlike a conventional circuit, discrimination is not made by integrating a logical code that includes “0” and “1” to some extent and produced from a random code, but repetition of an identical pattern of a well-known preamble signal added to a head portion of a signal is discriminated when a bit-rate of the signal is changed. More specifically, the repetition of the identical pattern is converted into a consecutive identical signal to generate the consecutive identical signal (having a length of tens bits to thousands bits). Although the consecutive identical signal is longer than a same-code continuation length included in the signal, and is shorter than a time constant necessary to the conventional circuit by about one to three digits. Therefore, an integration time can be shortened to the same degree as the generated consecutive identical signal length, and the bit-rate can be discriminated at high speed within a preamble signal receiving time.

Abstract: Golf ball 2 has core 4, cover 6 and paint layer 12. The base polymer of the cover 6 includes a thermoplastic polyurethane elastomer. The cover includes 0.1 parts by weight or more and 10 parts by weight or less of a hindered amine heat and light resistance stabilizer having a hindered phenol group, per 100 parts by weight of the base polymer. Preferably, the hindered amine heat and light resistance stabilizer has two or more hindered phenol groups in the molecule. It is preferred that the cover 6 further includes an ultraviolet ray absorbing agent and a heat resistance stabilizer. Provided that the molar concentration of the hindered amine heat and light resistance stabilizer is defined as A, and the molar concentration of the ultraviolet ray absorbing agent is defined as B, the molar ratio (A/B) is preferably 0.01 or greater and 2.5 or less. The cover 6 may further include a heat resistance stabilizer.

Abstract: A cross-sectional shape of each of dimples 8 of a golf ball is a wave-like curve. The wave-like curve has two first projections 16, two second projections 18, two first recesses 20, and two second recesses 22. A circular arc 14 passes through one edge Ed, a deepest point Pd, and another edge Ed. Each first projection 16 is located above the circular arc 14. Each second projection 18 is located above the circular arc 14. Each first recess 20 is located below the circular arc 14. Each second recess 22 is located below the circular arc 14. The ratio of the distance Lp from an edge Ed to a peak Pp to the radius (Di/2) of the dimple 8 is equal to or greater than 20% but equal to or less than 70%.

Abstract: A ball 2 has, in a ball surface layer area, an aroma layer 16 including a scent component. The aroma layer 16 is provided locally. The aroma layer 16 may be provided on the entire surface. The scent component is preferably at least one member selected from the group consisting of terpenes, ester compounds, aromatic compounds, ether compounds, aldehyde compounds, alcohol compounds, natural essential oils, hydrocarbons, ketone compounds, lactone compounds, and nitrogen-containing compounds. A perfume-material-encapsulating microcapsule may be used. The local aroma layer 16 is preferably provided by stamping. The aroma layer may be formed by spraying. A scent adsorbent may be further used. Preferably, the golf ball 2 is put into a package 20.

Abstract: At all points Pa included in zone “A” away from the central point of the core 4 at a distance of 1 mm or greater and less than 5 mm, the following mathematical expression (I) is satisfied, and at any point Pb included in zone “B” away from the central point of the core 4 at a distance of 5 mm or greater and 10 mm or less, the following mathematical expression (II) is satisfied. Ha2?Ha1<5??(I) Hb2?Hb1?5??(II) Ha1 represents the hardness at a point Pa1 that is located inside the point Pa along the radial direction and away from the point Pa at a distance of 1 mm, and Ha2 represents the hardness at a point Pa2 that is located outside the point Pa along the radial direction and away from the point Pa at a distance of 1 mm.

Abstract: A golf ball 2 has a spherical core 4, a mid layer 6 situated on the external side of the core 4, and a cover 8 situated on the external side of the mid layer 6. The core 4 has a spherical center 10 and an envelope layer 12 situated on the external side of the center 10. At all points P included in a zone away from the central point of the core 4 at a distance of 1 mm or greater and 15 mm or less, the following mathematical expression is satisfied. H2?H1?5 In the above mathematical expression, H1 represents the JIS-C hardness at a point P1 that is located inside the point P along the radial direction and away from the point P at a distance of 1 mm, and H2 represents the JIS-C hardness at a point P2 that is located outside the point P along the radial direction and away from the point P at a distance of 1 mm.

Abstract: A cross-sectional shape of each of dimples 8 of a golf ball 2 is a wave-like curve. The wave-like curve has two first curves 14, two second curves 16, two third curves 18, and one fourth curve 20. Each first curve 14 and each third curve 18 are upwardly convex. Each second curve 16 and the fourth curve 20 are downwardly convex. Each first curve 14 is connoted to a land 10 at an edge Ed. Each second curve 16 is connected to the first curve 14 at a first inflexion point 22. Each third curve 18 is connected to the second curve 16 at a second inflexion point 24. The fourth curve 20 is connected to the third curves 18 at third inflexion points 26. In the wave-like curve, the upwardly convex curves 14 and 18 and the downwardly convex curves 16 and 20 are alternately arranged.

Abstract: Golf ball 2 has spherical core 4, surrounding layer 6 situated on the external side of the core 4, mid layer 8 situated on the external side of the surrounding layer 6, cover 10 situated on the external side of the mid layer 8, and paint layer 12 situated on the external side of the cover 10. The mid layer 8 has a thickness Tm of 0.1 mm or greater and 1.2 mm or less. The ratio (Tc/Tm) of the thickness Tc of the cover 10 to the thickness Tm of the mid layer 8 is no greater than 0.50. The cover 10 has a Shore D hardness Hc of no greater than 35. The Shore D hardness Hm of the mid layer 8 is greater than the Shore D hardness Hc of the cover 10. The base material of the surrounding layer 6 is an ionomer resin. The base material of the mid layer 8 is a polyurethane. The base material of the cover 10 is a polyurethane.

Abstract: A modulation method according to the invention is applied to a modulation device in which a light source is driven by a differential signal while a modulation circuit and the light source are capacitively coupled. In the modulation method of the invention, when an average potential fluctuates at an input terminal of the light source, a potential fluctuation is externally provided using a control circuit such that a normal phase side and a reverse phase side become equal to each other in a time constant of the fluctuation in average potential, and transient states of the average potentials at the normal phase side and reverse phase side are equalized and cancel each other as in-phase components of a signal input to the light source, which allows an optical signal to be normally transmitted from the light source.

Abstract: The golf ball 2 has a northern hemisphere N and a southern hemisphere S. The northern hemisphere N is adjacent to the southern hemisphere S across an equatorial line Eq. Each of the northern hemisphere N and the southern hemisphere S has a pole vicinity region 14 and an equator vicinity region 16. Each of the pole vicinity region 14 and the equator vicinity region 16 has a large number of dimples. The dimple pattern of the pole vicinity region 14 includes three units that are rotationally symmetrical to each other about a pole Po. The dimple pattern of the equator vicinity region 16 includes six units that are rotationally symmetrical to each other about the pole Po. The sum (Ps+Pp) of a peak value Ps and a peak value Pp of the golf ball 2 is equal to or greater than 600 mm.

Abstract: An object of the present invention is to provide a golf ball having an individualized and improved appearance by imparting the luster, without lowering durability and a color developing property of the paint film and/or the mark. Another object of the present invention is to provide a golf ball having an improved visibility, which the mark should inherently provide. The present invention provides a golf ball comprising a golf ball body, a mark formed on the golf ball body, a paint film coating the golf ball body and the mark, wherein the mark and/or the paint film contains a luster material, wherein the luster material has a core material having a transparent base and a first transparent layer formed on the transparent base; and at least one composite layer formed on the core material and consisting of a second transparent layer having a lower refractive index than the first transparent layer, and a third transparent layer having a higher refractive index than the second transparent layer.

Abstract: A golf ball 2 includes a spherical core 4, a mid layer 6 positioned outside the core 4, and a cover 8 positioned outside the mid layer 6. The core 4 includes a spherical center 10 and an envelope layer 12 positioned outside the center 10. The center 10 has a diameter of 1 mm or greater and 15 mm or less. The center 10 has a JIS-C hardness H1, at its central point, of 20 or greater and 50 or less. The difference (H4?H3) between the JIS-C hardness H4 of the core 4 at its surface and the JIS-C hardness H3 of the envelope layer 12 at its innermost portion is equal to or greater than 10. The cover 8 has a flexural modulus of 300 MPa or greater and 1000 MPa or less, and has a tensile modulus of 400 MPa or greater and 1500 MPa or less.