1 Description Title of Invention: PNEUMATIC TIRE Technical Field [0001] The present invention relates to a pneumatic tire having a tire identification mark on at least one of a pair of sidewall portions. Background Art [0002] A tire identification mark constituted of letters, symbols, or a combination of them representing a name of a manufacturer and a tire type is provided on a surface of a sidewall portion of a pneumatic tire. There is a technique which has already been proposed and in which either one of a tire identification mark and a region surrounding letters and symbols of the tire identification mark is constituted of a large number of ridges and the other of them is constituted of a flat and smooth face to improve identification of the tire identification mark in a prior-art pneumatic tire (see Patent Documents 1 and 2). [0003] In each of the tires described in the Patent Documents 1 and 2, the tire identification mark is constituted of a large number of ridges, the letters and symbols of the tire identification mark are surrounded with a flat and smooth face, and the tire identification mark and the flat and smooth face are arranged between two regions constituted of a large number of ridges on opposite sides of the tire circumferential direction. This type of tire can be expected to exert a certain degree of visibility of the tire identification mark. Citation List Patent Literature [0004] [PTL1] Japanese Patent Application Laid-Open No. 2009-90950 [PTL2] Japanese Patent Application Laid-Open No. 2009-67355 Summary of the Invention [0005] However, there is always a demand for a higher level of visibility of the tire identification mark. It is a preferred aim of the present invention to provide a pneumatic tire with further improved visibility of a tire identification mark formed on a sidewall portion.
2 [0006] In one broad form, the invention provides a pneumatic tire having a tire identification mark on at least one of a pair of sidewall portions thereof. The tire includes: at least two decoration regions, each decorated with a large number of ridges; a no-decoration region arranged between the decoration regions in a tire circumferential direction and having a flat and smooth face without ridges; and a mark indicating region including the tire identification mark made up of a letter, a symbol, or a combination of the letter and the symbol, each of the letter and the symbol surrounded with the no-decoration region. Each of the decoration regions has at least two kinds of regions having different ridge intervals. The tire comprises a tire outer decoration region disposed to be adjacent to an outside of the no-decoration regions in a tire radial direction and including a large number of ridges. Each of the decoration regions includes a first ridge portion adjacent to the no-decoration region and a second ridge portion adjacent to a side of the first ridge portion extending away from the no-decoration region and having wider ridge intervals than those of the first ridge portion. Ridge intervals in the tire outer decoration region are wider than the ridge intervals in the first ridge portion and narrower than the ridge intervals in the second ridge portion. [0007] Preferably, the mark indicating region is a recessed portion region having a bottom portion recessed from the flat and smooth face and a large number of ridges protruding from the bottom portion and heights of the ridges in the mark indicating region from the bottom portion are smaller than the recessed depth of the bottom portion from the flat and smooth face. [0008] In an embodiment of the tire, the first ridge portion is formed in a substantial triangular shape made up of a vertex and an opposite side facing to the vertex of the substantial triangular shape, the opposite side disposed along a side of the no-decoration region. A boundary between the first ridge portion and the second ridge portion is extended and inclined at 10 to 45 degrees with respect to the tire circumferential direction. [0009] In the embodiment, ridges in the first and second ridge portions are preferably formed in the same direction at least in a portion where the first ridge portion and the second ridge portion are in contact with each other. [0010] In embodiments of the tire, two marks are displayed at opposite positions on a tire circumference of at least one of the pair of sidewall portions, and each of the two marks is indicated as the tire identification mark in the mark indicating region. [0011] In embodiments of the tire, two marks are indicated away from each other as the tire 3 identification mark on a tire circumference of at least one of the pair of sidewall portions. The decoration regions are provided on opposite sides in the tire circumferential direction and sandwiching the no-decoration regions which respectively surround the two marks. Each of the decoration regions includes two first ridge portions provided to extend closer to each other and a second ridge portion sandwiched between the two first ridge portions and having the different ridge intervals from those of the first ridge portions. Each of the first ridge portions is formed in a substantial triangular shape including a vertex and an opposite side facing to the vertex of the substantial triangular shape, the opposite side disposed along a side of the no-decoration region, and the second ridge portion is formed in a substantial crescent shape. [0013] The pneumatic tire may further include a tire inner decoration region disposed to be adjacent to an inside of the no-decoration region(s) in the tire radial direction and including a large number of ridges. Ridge intervals in the tire inner decoration region are preferably wider than those of the ridge intervals in the first ridge portion and narrower than those of the ridge intervals in the second ridge portion. [0014] Preferably, ridge intervals in the tire outer decoration region are narrower than ridge intervals in the tire inner decoration region. [0015] Preferably, ridge intervals in the mark indicating region are wider than the ridge intervals in the first ridge portion and narrower than the ridge intervals in the second ridge portion. Advantageous Effects of Invention [0016] In the pneumatic tire according to the above aspects, the two kinds of ridge portions having different ridge intervals appear to be dark and light in the decoration regions so that the decoration regions easily attract attention of a person who looks at the tire. As a result, eyes of the person who looks at the tire are easily directed to the mark indicating regions which are on extended lines from the decoration regions in the circumferential direction and visibility of the tire indication marks increases. Brief Description of Drawings [0017] [fig.1] HG. 1 is a side view of a pneumatic radial tire of an embodiment. [fig.2] HG. 2 is an enlarged partial side view of a part of a sidewall portion of the pneumatic radial tire illustrated in FIG. 1. [fig.3] HG. 3 is a sectional view of the sidewall portion along the line A-A in HG. 2. [fig.4A] HG. 4A indicates specifications of examples and prior-art examples of the embodiment.
4 [fig.4B] FIG. 4B indicates specifications of examples and prior-art examples of the embodiment. [fig.5A] FIG. 5A indicates specifications of examples of the embodiment. [fig.5B] FIG. 5B indicates specifications of examples of the embodiment. [fig.5C] FIG. 5C indicates specifications of examples of the embodiment. [fig.6A] FIG. 6A indicates specifications of examples of the embodiment. [fig.6B] FIG. 6B indicates specifications of examples of the embodiment. [fig.6C] FIG. 6C indicates specifications of examples of the embodiment. Description of Embodiments [0018] A pneumatic tire of the invention will be described below in detail. FIG. 1 is a side view of a pneumatic radial tire (hereafter referred to as "tire") 10 of a present embodiment. The tire 10 is a tire for a passenger car. A sidewall portion (described later) of the tire 10 can be used for a tire for heavy load, a tire for an aircraft, a tire for a construction vehicle, a tire for a two-wheel vehicle, and the like and is not limited to use for a certain type of tire. Heights of ridges and ridge intervals described below are numerical examples of the tire for the passenger car. The tire 10 includes a tread portion 12, sidewall portions 14, and bead portions 16. The tire 10 also includes a carcass layer, an inner liner layer, a belt layer, and the like, though they are not illustrated. The sidewall portions 14 and the bead portions 16 are disposed on opposite sides of a tire width direction to sandwich the tread portion 12 and pair up with each other, respectively. FIG. 1 illustrates only visible outlines in a tire radial direction of the tread portion 12 and the bead portions 16. In the description, the tire width direction refers to a direction parallel to a tire rotation axis, the tire circumferential direction refers to a circumferential direction of rotation when the tire is seen as a rotating body, and the tire radial direction refers to a radial direction when the tire is seen as the rotating body. [0019] As the tread portion 12, the bead portions 16, the carcass layer, the inner liner layer, the belt layer, and the like, well-known members may be employed or new members may be employed and they are not especially limited in the tire 10. A surface of at least one of the sidewall portions 14 has a form illustrated in FIGS. 1 or 2 and mark indicating regions 11, no-decoration regions 3, decoration regions 5, a tire outer decoration region 8, and a tire inner decoration region 9 are formed on the surface. Each of the mark indicating regions 11 is positioned in the no-decoration region 3. These regions 11, 3, 5, 8, and 9 may be provided on one or 5 both of the pair of sidewall portions 14. If they are provided on one of the sidewall portions 14, they are preferably provided on a sidewall portion 14 positioned on an outer side of a vehicle to which the tire 10 is mounted. [0020] (Mark Indicating Region) The mark indicating region 11 is a region in which a tire identification mark (hereafter referred to as "mark") constituted of letters, symbols, or a combination of them is indicated. The mark indicating region 11 may be disposed on the tire circumference or the plurality of mark indicating regions 11 may be disposed away from each other on the tire circumference. In this embodiment, the mark indicating regions 11 are disposed at two opposite positions of the tire 10 on the tire circumference. Specifically, the mark indicating regions 11 are disposed at such tire circumferential positions that their central positions in the tire circumferential direction are away from each other by 160 degrees to 200 degrees. The mark 1 is constituted of the letters, the symbols, or the combination of them representing the name of a manufacturer, the name of a brand, the tire size, and the like. The number of letters and symbols constituting the mark 1 may be one or more. The symbols include numbers. The letters and the symbols respectively include designs thereof. In the tire 10 illustrated in FIG. 1, the mark 1 in the upper mark indicating region 11 is constituted of a design of a letter y disposed at the left end and a string of letters, "YOKOHAMA" disposed to the right of and to be adjacent to the design. The mark 1 in the lower mark indicating region 11 is constituted of a string of letters, "ABCDE". The letters and the symbols constituting the mark 1 are respectively surrounded with the no-decoration regions 3. [0021] The mark indicating region 11 excluding a region of the design of the letter y includes recessed portion regions 1c each having a bottom portion la recessed with reference to a flat and smooth face 3a (described later) of the no-decoration region 3 and a large number of ridges lb protruding from the bottom portion la as illustrated in FIGS. 2 and 3. FIG. 2 is an enlarged view of a part of the sidewall portion 14 of the tire 10. FIG. 3 is an A-A cross section at a position of "0" of "YOKOHAMA" in FIG. 2. Because the mark indicating region 11 has these recessed portion regions 1c, it looks darker than the other region on the side face of the tire 10 to improve visibility of the mark 1. For example, the no-decoration region 3 looks whitish (low density of the surface color) due to components of specularly-reflected light and the like of light on the flat and smooth face 3a in the no-decoration region 3, while the mark indicating region 11 looks dark (high density of the surface color) due to components of scattered reflected light. In each of the recessed portion regions 1c, the heights of the ridges lb from the bottom portion la are preferably smaller than the recessed depth of 6 the bottom portion la from the flat and smooth face 3a in order to suppress the specularly reflected light in the mark indicating region. For example, the height of the ridges lb from the bottom portion 1 a is 0.3 mm while the recessed depth of the recessed portion region 1c is 0.5 mm from the flat and smooth face 3a as illustrated in FIG. 3. [0022] The ridge intervals between the ridges lb are preferably wider than the ridge intervals of ridges 6c of first ridge portions 6 (described later) and are preferably narrower than ridge intervals of ridges 7a of second ridge portions 7 (described later) in order to obtain an optimum range of reflected light. The ridge interval in the invention refers to a distance between highest points of the two adjacent ridges. The direction in which the ridges lb extend is not especially limited. The direction is, for example, the same as the direction in which the ridges 6c in the first ridge portions 6c and the ridges 7a in the second ridge portions 7 extend. The region of the design of the letter y of the mark indicating region 11 is constituted of a recessed portion region having the bottom portion la recessed with reference to the flat and smooth face 3a and does not include a large number of ridges. It is of course possible to form the large number of ridges lb in the region of the letter y similarly to "YOKOHAMA". [0023] (No-decoration Region) The no-decoration regions 3 are disposed at two opposite positions on the tire circumference to correspond to the positions on the tire circumference where the two mark indicating regions 11 are disposed. Each of the no-decoration regions 3 is arranged and sandwiched between the decoration regions 5 on the opposite sides in the tire circumferential direction. Each of the no-decoration regions 3 is constituted of the flat and smooth face 3a which is flat and smooth. [0024] (Decoration Region) The decoration regions 5 are disposed at two positions on the tire circumference and the two no-decoration regions 3 and the decoration regions 5 are disposed alternately side by side in the tire circumferential direction. Each of the decoration regions 5 is a region decorated with a large number of ridges and includes at least two types of regions having different ridge intervals, e.g., first ridge portions 6 and second ridge portions 7. [0025] The first ridge portions 6 are respectively disposed on opposite sides of each of the two mark indicating regions 11 and have such shapes as to direct eyes of a person who looks at the tire to each of the two mark indicating regions 11. Specifically, each of the first ridge portions 6 has a substantial triangular shape from the viewpoint of improvement of design quality and enhancement of visibility of the mark 1. The substantial triangular shape means that a triangular shape is modified for 7 corresponding to the annular sidewall portion into the substantial triangular shape. The substantial triangular shape has an end portion 6a on the side of the second ridge portion 7 as a vertex and a ridge 6b positioned at an edge of the first ridge portion 6 adjacent to the no-decoration region 3 as an opposite side facing to the vertex of the triangular shape. The ridge 6b corresponds to an opposite side facing to the vertex of the substantial triangular shape and is disposed along a side of the no-decoration region 3. The ridge 6b is a ridge protruding outward in the tire width direction from the flat and smooth face 3a to enhance a boundary with the no-decoration region 3. [0026] The first ridge portion 6 further includes the large number of ridges 6c in its inner region. The ridges 6c are formed to protrude from a bottom portion recessed from the same level as the flat and smooth face 3a of the no-decoration region 3. The height of the ridges 6c from the bottom portion is 0.5 mm while the recessed depth of the bottom portion is 0.5 mm. The intervals between the ridges 6c are 0.7 to 0.9 mm, for example, and are preferably 0.8 mm. The ridges 6c are formed to extend in the direction inclined to the tire circumferential direction from the tire radial direction. [0027] Each of the first ridge portions 6 further includes a ridge 6d extending from an end portion of the ridge 6b on the tire inner position toward the tip end portion 6a on a boundary with the second ridge portion 7. The ridge 6d is for enhancing the boundary with the second ridge portion 7 and is formed to have the same height as that of the ridge 6b. An angle of inclination of the ridge 6d with respect to the tire circumferential direction, i.e., an angle q which the ridge 6d forms with a ridge 9a in a tire inner decoration region 9 (described later) is preferably 10 to 45 degrees from a viewpoint of increase of the area of the first ridge portion 6 and enhancement of visibility of the mark 1, for example, 30 degrees. [0028] Each of the second ridge portions 7 is disposed adjacent to the first ridge portion 6 on the opposite side of the no-decoration region 3 in the tire circumferential direction and is sandwiched between the two first ridge portions 6 corresponding to the decoration regions 5. Each of the second ridge portions 7 is substantially in a shape of a crescent. [0029] Each of the second ridge portions 7 includes the large number of ridges 7a. The ridges 7a are formed to protrude from a bottom portion which is recessed from the same level as that of the flat and smooth face 3a of the no-decoration region 3. The height of the ridges 7a from the bottom portion is 0.5 mm while the recessed depth of the bottom portion is 0.5 mm, for example. The intervals between the ridges 7a are different from the intervals between the ridges 6c in the first ridge portions 6. The intervals between the ridges 7a are preferably wider than the ridge intervals in the first ridge portions 6. For example, the intervals between the ridges 7a are 1.3 to 3.0 times the intervals between the ridges 6c 8 in the first ridge portions 6. By setting the intervals between the ridges 7a like this, the two ridge portions 6 and 7 having different ridge intervals appear to be dark and light (different in lightness) on the sidewall portion 14 of the tire 10 so that the decoration regions 5 easily attract attention of the person who looks at the tire. As a result, the eyes of the person who looks at the tire are easily directed to the no-decoration regions 3 and the mark indicating regions 11 adjacent to the decoration regions 5 in the tire circumferential direction and the visibility of the marks 1 increases. In this embodiment, the intervals between the ridges 6c in the first ridge portions 6 are the narrowest and the first ridge portions 6 look dark on the sidewall portion 14 of the tire 10, which emphasizes lightness of the no-decoration regions 3 adjacent to the first ridge portions 6 to effectively enhance visibility of the marks 1 surrounded with the no-decoration regions 3. The ridges 7a of the second ridge portion 7 are inclined in the tire circumferential direction at the same angle as the inclination angle of the ridges 6c of the first ridge portion 6 in the tire circumferential direction. Therefore, it is possible to naturally direct the eyes of the person who looks at the tire to the marks 1 without recognition of a change of the region between the first ridge portion 6 and the second ridge portion 7. Furthermore, it is possible to suppress reversal of darkness and lightness of the second ridge portions 7 and the first ridge portions 6 due to an angle at which the side face of the tire 10 is seen, thereby avoiding reduction in the visibility of the marks 1. [0030] (Tire Outer Decoration Region) The tire outer decoration region 8 is disposed to be adjacent to the no-decoration regions 3 and the decoration regions 5 on the outer side of the regions 3 and 5 in the tire radial direction. The tire outer decoration region 8 includes the ridge 8a extending in the tire circumferential direction on boundaries with the no-decoration regions 3 and the decoration regions 5. The ridge 8a is for enhancing the boundaries with the nodecoration regions 3 and the decoration regions 5. For example, the ridge 8a is formed to have the same height as that of the ridge 6b. [0031] The tire outer decoration region 8 further includes a large number of ridges 8b slightly spaced from the ridge 8a on the outer side in the tire radial direction. The ridges 8b are formed to protrude from a bottom portion which is recessed from the same level as the flat and smooth faces 3a of the no-decoration regions 3. The height of the ridges 8b from the bottom portion is 0.5 mm while the recessed depth of the bottom portion is 0.5 mm. The intervals between the ridges 8b are preferably wider than the intervals between the ridges 6c in the first ridge portions 6 and are preferably narrower than the intervals between the ridges 7a in the second ridge portions 7 from a viewpoint of enhancement of the visibility of the marks 1. For example, the intervals between the ridges 8b are 1.1 9 to 2.0 times the intervals between the ridges 6c in the first ridge portions 6. The intervals between the ridges 8b are preferably narrower than the intervals between ridges 9b in a tire inner decoration region 9 (described later). By setting the intervals between the ridges 8b this way, it is possible to attract attention to the tire outer decoration region 8 to enhance visibility of the marks 1 surrounded with the no-decoration regions 3 adjacent to the tire outer decoration region 8. The direction in which the ridges 8b extend is not especially limited. The direction is, for example, the same as the direction in which the ridges 6c in the first ridge portions 6 and the ridges 7a in the second ridge portions 7 extend. [0032] (Tire Inner Decoration Region) The tire inner decoration region 9 is disposed to be adjacent to the no-decoration regions 3 and the decoration regions 5 on the inner side of the regions 3 and 5 in the tire radial direction. The tire inner decoration region 9 includes the ridge 9a extending in the tire circumferential direction on boundaries with the no-decoration regions 3 and the decoration regions 5. The ridge 9a is for enhancing the boundaries with the no-decoration regions 3 and the decoration regions 5. For example, the ridge 9a is formed to have the same height as that of the ridge 6b. [0033] The tire inner decoration region 9 further includes a large number of ridges 9b being in contact with the ridge 9a. The ridges 9b are formed to protrude from a bottom portion which is recessed from the same level as that of the flat and smooth faces 3a of the no-decoration regions 3. The height of the ridges 9b from the bottom portion is 0.5 mm while the recessed depth is 0.5 mm, for example. The intervals between the ridges 9b are preferably wider than the intervals between the ridges 6c in the first ridge portions 6 and are preferably narrower than the intervals between the ridges 7a in the second ridge portions 7. For example, the intervals between the ridges 9b are 1.2 to 2.5 times the intervals between the ridges 6c in the first ridge portions 6. By setting the intervals between the ridges 9b in this manner, it is possible to attract attention also to the tire inner decoration region 9 to enhance visibility of the marks 1 surrounded with the no-decoration regions 3 adjacent to the tire inner decoration region 9. A direction in which the ridges 9b extend is not especially limited. The direction in which the ridges 9b extend is a direction orthogonal to the directions in which the ridges 6c in the first ridge portions 6, the ridges 7a in the second ridge portions 7, and the ridges 8b in the tire outer decoration region 8 extend. [0034] In the embodiment, the mark indicating regions may not include the large number of ridges. Each of the mark indicating regions may include faces at the same level as that of the flat and smooth portion or faces protruding from the flat and smooth portion instead of the recessed portion regions and the large number of ridges formed on the faces. The large number of ridges in the mark indication 10 regions may have the same height as that of the large number of ridges in the first ridge portions. Each of the decoration regions may include three or more regions having different ridge intervals. The angles of the boundaries between the first ridge portions and the second ridge portion with respect to the tire circumferential direction may be smaller than 10 degrees or greater than 45 degrees. The direction in which the large number of ridges in the first ridge portions extend and the direction in which the large number of ridges in the second ridge portions extend may not be the same but may be orthogonal to each other. The large number of ridges in each of the second ridge portions may be extending in the same direction as that of the ridges in each of the first ridge portions only in a region (e.g., in the same tire circumferential region as the first ridge portion) adjacent to the boundary with the large number of ridges in the first ridge portion. [0035] The first ridge portions and the second ridge portions do not necessarily include the substantial triangular shapes and the substantial crescent shapes, respectively. They may be formed in rectangular shapes extending along the tire circumferential direction. The ridge intervals in the tire outer decoration region may be wider than or the same as the ridge intervals in the tire inner decoration region. The dimensional relationships between the ridge intervals between the large number of ridges in the first ridge portions, the second ridge portions, and the tire outer decoration region, the dimensional relationships between the ridge intervals between the large number of ridges in the first ridge portion, the second ridge portion, and the tire inner decoration region, and the dimensional relationships between the ridge intervals between the ridges in the mark indicating regions and the large number of ridges in the first ridge portions and the second ridge portions are not limited to those described above. Although the tire outer decoration region and the tire inner decoration region are provided in the embodiment, these regions need not be provided. [0036] (Example) To study effects of the tire of the invention, tires (195/65R15 91H) having various different specifications of sidewall portions were produced experimentally and visibility of marks was evaluated. Evaluation of the visibility was carried out by mounting the experimentally produced tire to a rim, inflating the tire up to internal pressure of 210 kPa, mounting the tire to a passenger car. Whether 20 monitors, who stood at a distance of 1m in a direction inclined 45 degrees leftward with respect to a tire width direction respectively and saw the tire, could visually recognize the mark or not was checked. The result of the check was obtained as indexes. The higher the index, the more excellent the visibility 11 is. [0037] (Examples 1 to 18, Prior-art Examples 1 and 2) Detailed specifications and evaluation results of the embodiments 1 to 18 and prior art examples 1 and 2 are indicated in Tables 1A to 3C of FIGs.4A to 6C. In Tables 1A to 3C, in the row of "disposed positions of a large number of ridges with reference to no-decoration region", "circumferential opposite sides of no-decoration region" mean that only the first ridge portions are formed as regions adjacent to the no-decoration region and that the tire outer decoration region and the tire inner decoration region are not formed. "Four sides of no-decoration region" mean that the first ridge portions, the tire outer decoration region, and the tire inner decoration region are formed as regions adjacent to the no-decoration region. With regard to hyphenated "large", "intermediate", "small", and "no ridges", "large-intermediate-small" in the row of "Dimensional relationships between ridge intervals between a large number of ridges in first ridge portion, second ridge portion, and tire outer decoration region" means that the ridge intervals in the first ridge portions are the largest, the ridge intervals in the tire outer decoration region are the smallest, and the ridge intervals in the second ridge portion are intermediate between them, for example. In the row, "intennediate-intennediate-no ridges" means that there is no difference between the ridge intervals in the first ridge portion and the ridge intervals in the second ridge portion and that a large number of ridges are not formed in the tire outer decoration region. Similarly, with regard to hyphenated substantial triangle and substantial crescent, "substantial triangle-substantial crescent-substantial triangle shape" in the row of "shapes of first ridge portion, second ridge portion, and first ridge portion disposed in one decoration region" means that the two first ridge portions are substantially triangular and the second ridge portion is in the substantial crescent shape, for example. "Substantial parallelogram" means that the first ridge portion and the second ridge portion are rectangular shapes extending in the tire circumferential direction, respectively. [0038] In the row of "Height of mark indicating region from flat and smooth face in recessed portion region", "-0.5 mm" means that the mark indicating region is recessed 0.5 mm from the flat and smooth region and "0.5 mm" means that the mark indicating region is protruding 0.5 mm from the flat and smooth face. In the row of "Relationship between extending direction of the large number of ridges in the first ridge portion and extending direction of the large number of ridges in the second ridge portion", "parallel" means that the large number of ridges in the first ridge portion and the large number of ridges in the second ridge portion are extending in the same direction at the same inclination angle and 12 "perpendicular" means that the two types of ridges are extending in directions orthogonal to each other. [0039] From the evaluation results of the prior-art example 2 and the examples 1 to 18, it is found that excellent visibility can be obtained, by making the ridge intervals in the first ridge portion and the ridge intervals in the second ridge portion different from each other. From the evaluation results of the prior-art example 1 and the examples 1 to 18, it is found that excellent visibility can be obtained, by making the ridge intervals in the first ridge portion and the ridge intervals in the second ridge portion different from each other and by disposing the mark indicating region in the recessed region which is recessed from the flat and smooth face. From the evaluation results of the examples 1 and 3, it is found that more excellent visibility can be obtained, by making the ridge intervals in the first ridge portion narrower than those in the second ridge portion. From the evaluation results of the examples 2 and 3, it is found that more excellent visibility can be obtained, by forming the large number of ridge portions in the mark indicating region. From the evaluation results of the examples 3 and 4, it is found that more excellent visibility can be obtained, by making the heights of the large number of ridges in the mark indicating region are smaller than recessed depth from flat and smooth face. [0040] From the evaluation results of the examples 3 and 5 to 8, it is found that more excellent visibility can be obtained, by setting the angle of the boundary between the first ridge portion and the second ridge portion with respect to the tire circumferential direction to 10 to 45 degrees. From the evaluation results of the examples 3 and 9, it is found that more excellent visibility can be obtained, by making the large number of ridges in the first ridge portion and the large number of ridges in the second ridge portion parallel. From the evaluation results of the examples 3 and 10, it is found that more excellent visibility can be obtained, by forming the first ridge portions in the substantial triangular shapes and the second ridge portions in the substantial crescent shape. From the evaluation results of the examples 3 and 11, it is found that more excellent visibility can be obtained, by forming the large numbers of ridges in the tire outer decoration region and the tire inner decoration region. [0041] From the evaluation results of the examples 3 and 12, it is found that more excellent visibility can be obtained, by making the ridge intervals in the tire outer decoration region narrower than those in the second ridge portion and by making the ridge intervals in the tire outer decoration region narrower than those in the tire inner decoration region.
13 From the evaluation results of the examples 3 and 13, it is found that more excellent visibility can be obtained, by making the ridge intervals in the first ridge portion narrower than those in the tire outer decoration region. From the evaluation results of the examples 3 and 14, it is found that more excellent visibility can be obtained, by making the ridge intervals in the tire inner decoration region narrower than those in the second ridge portion. From the evaluation results of the examples 3 and 15, it is found that more excellent visibility can be obtained, by making the ridge intervals in the first ridge portion narrower than those in the tire inner decoration region. From the evaluation results of the examples 3 and 16, it is found that more excellent visibility can be obtained, by making the ridge intervals in the tire outer decoration region narrower than those in the tire inner decoration region. From the evaluation results of the examples 3 and 17, it is found that more excellent visibility can be obtained, by making the ridge intervals in the first ridge portion narrower than those in the mark indicating region. From the evaluation results of the examples 3 and 18, it is found that more excellent visibility can be obtained, by making the ridge intervals in the mark indicating region narrower than those in the second ridge portion. [0042] Although the pneumatic tire of the invention has been described above in detail, it is needless to say that the invention is not limited to the above embodiment and can be improved or changed in various ways without departing from the gist of the invention. [0043] The term "comprise" and variants of that term such as "comprises" or "comprising" are used herein to denote the inclusion of a stated integer or integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive interpretation of the term is required. [0044] Reference to prior art disclosures in this specification is not an admission that the disclosures constitute common general knowledge in Australia.
14 Reference Signs List [0043] 1 tire identification mark la bottom portion 1b, 6c, 7a, 8b, 9b ridge 3 no-decoration region 3a flat and smooth face 5 decoration region 6 first ridge portion 6a tip end portion (vertex) 6b ridge (opposite side) 7 second ridge portion 8 tire outer decoration region 9 tire inner decoration region 10 pneumatic tire 11 mark indicating region 12 tread portion 14 sidewall portion