Wristwatch

Abstract

To provide a wristwatch which achieves both suppression of reduction in power generation amount when a part of a solar panel is shielded from light and suppression of total extension of a boundary line.SOLUTION: A solar panel 4 of a wristwatch 1 includes a plurality of solar cells connected in series, the plurality of solar cells have equal light receiving areas, each of the solar cells has a first region disposed on a nine o'clock side and a second region disposed on a three o'clock side with respect to an imaginary line IL connecting twelve o'clock and six o'clock, in one of the solar cells, a light receiving area of the first region and a light receiving area of the second region are equal, a boundary Bj between two adjacent solar cells has a first end B11, B21, B31, B41, B51 located on the nine o'clock side and a second end B12, B22, B32, B42, B52 located on the three o'clock side with respect to the imaginary line, and the first end and the second end are disposed at positions facing each other with the imaginary line interposed therebetween.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wristwatch. [Background technology]

[0002] There have been conventional timepieces equipped with solar cells. Patent Document 1 discloses an electronic timepiece equipped with a solar cell, which includes a solar cell and a translucent dial attached to the front side of the solar cell. The solar cell includes a first solar cell, a second solar cell, and a third solar cell, which are divided into three sectors by a dividing line passing through the center of the dial. The first and second solar cells are arranged across two left and right regions separated by a line connecting the 12 o'clock and 6 o'clock markers on the dial, and the third solar cell is arranged in only one of the two left and right regions.

[0003] Patent Document 2 discloses a solar panel having a plurality of solar cells arranged in a substantially circular shape. In Patent Document 2, the plurality of solar cells are formed by dividing a pointer that moves above the solar cells into a substantially spiral shape that always overlaps at least two of the plurality of solar cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-108908 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-169916 Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable for a wristwatch to be able to suppress a decrease in power generation when a portion of the solar panel is shaded by the user's sleeve, etc. For example, in the solar-powered electronic watch of Patent Document 1, if the area where the third solar cell is located, one of the two left and right areas, is shaded, the solar cell will not be able to generate power. It is preferable that even if one of the two areas on the solar panel is shaded, the other area can still generate power.

[0006] Furthermore, in a solar panel having a plurality of solar cells, if the total length of the boundary lines between adjacent solar cells becomes long, this will result in a decrease in the light-receiving area.

[0007] The object of the present invention is to provide a wristwatch that can simultaneously suppress the decrease in power generation when part of the solar panel is shaded and suppress the total length of the boundary line. [Means for solving the problem]

[0008] The wristwatch of the present invention comprises a dial and a solar panel arranged on the back side of the dial, the solar panel including a plurality of solar cells connected in series, the plurality of solar cells having equal light-receiving areas, each of the solar cells having a first region arranged on the 9 o'clock side of an imaginary line connecting 12 o'clock and 6 o'clock, and a second region arranged on the 3 o'clock side of the imaginary line, the light-receiving area of ​​the first region and the light-receiving area of ​​the second region being equal in one solar cell, the boundary between two adjacent solar cells having a first end located on the 9 o'clock side of the imaginary line and a second end located on the 3 o'clock side of the imaginary line, and the first end and the second end of one of the boundary lines being arranged in positions facing each other with the imaginary line between them. [Effects of the Invention]

[0009] In a wristwatch according to the present invention, the boundary between two adjacent solar cells has a first end located on the nine o'clock side of an imaginary line and a second end located on the three o'clock side of the imaginary line, and the first end and second end of each boundary are positioned opposite each other with the imaginary line between them. A wristwatch according to the present invention has the effect of suppressing a decrease in power generation when part of the solar panel is shaded, while also suppressing the total length of the boundary. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view of a wristwatch according to an embodiment. [Figure 2] FIG. 2 is a plan view of the solar panel according to the embodiment. [Figure 3] FIG. 3 is a plan view showing the positional relationship between the solar panel and the hour characters according to the embodiment. [Figure 4] FIG. 4 is a plan view showing the positional relationship between the solar panel and the cutout according to the embodiment. [Figure 5] FIG. 5 is a plan view showing the protruding portion of the first cell according to the embodiment. [Figure 6] FIG. 6 is a plan view showing the overlap between the solar panel and the pointer. [Figure 7] FIG. 7 is a plan view showing the overlap between the solar panel and the pointer. [Figure 8] FIG. 8 is a plan view showing the protruding portion of the second cell according to the embodiment. [Figure 9] FIG. 9 is a plan view showing the overlap between the solar panel and the pointer. [Figure 10] FIG. 10 is a plan view showing the protruding portion of the third cell according to the embodiment. [Figure 11] FIG. 11 is a plan view showing the overlap between the solar panel and the pointer. [Figure 12] FIG. 12 is a plan view showing the protruding portion of the fifth cell according to the embodiment. [Figure 13]FIG. 13 is a plan view showing the overlap between the solar panel and the pointer. [Figure 14] FIG. 14 is a plan view showing the protruding portion of the sixth cell according to the embodiment. [Figure 15] FIG. 15 is a plan view showing the overlap between the solar panel and the pointer. [Figure 16] FIG. 16 is a plan view of another solar panel according to the embodiment. [Figure 17] FIG. 17 is a plan view of another solar panel according to the embodiment. [Figure 18] FIG. 18 is a plan view of another solar panel according to the embodiment. [Figure 19] FIG. 19 is a plan view of another solar panel according to the embodiment. [Figure 20] FIG. 20 is a plan view of another solar panel according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A wristwatch according to an embodiment of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to this embodiment. Furthermore, the components in the following embodiments include those that would be easily conceivable to a person skilled in the art or that are substantially identical.

[0012] [Embodiment] An embodiment will be described with reference to Figs. 1 to 20. This embodiment relates to a wristwatch. The wristwatch 1 of this embodiment is a timepiece worn on the user's wrist, such as an electronic watch. As shown in Fig. 1, the wristwatch 1 of this embodiment has an outer case 2, hands 3, a solar panel 4, a crystal 11, a battery 12, a dial 31, a first button 35, a second button 36, and a crown 37. The hands 3 have a second hand 32, a minute hand 33, and an hour hand 34. The outer case 2 has a substantially cylindrical case body 21 and a lug 22.

[0013] First button 35, second button 36, and crown 37 are disposed on case body 21. First button 35 and second button 36 are push buttons that protrude from the outer peripheral surface of case body 21. First button 35 and second button 36 are disposed at intervals along the circumferential direction of case body 21. Crown 37 is disposed between first button 35 and second button 36.

[0014] The hands 3, dial 31, solar panel 4, and battery 12 are housed in the internal space of case body 21. A transparent crystal 11 closes the opening on the front side of case body 21. The solar panel 4 is a photoelectric conversion device that generates electricity from the light it receives. The solar panel 4 is connected to battery 12 via a control circuit. The electricity generated by the solar panel 4 is stored in battery 12. The control circuit is, for example, a control IC that controls wristwatch 1. The control circuit has the function of controlling the charging and discharging of battery 12. The control circuit prohibits the battery 12 from storing electricity when the voltage of battery 12 has risen to a sufficient voltage due to charging.

[0015] The solar panel 4 is disposed on the back side of the dial 31. In other words, the solar panel 4 is disposed on the opposite side of the dial 31 from the crystal 11 side. The dial 31 in this embodiment has a circular shape. The dial 31 is configured to transmit light from the crystal 11 side to the solar panel 4 side.

[0016] A plurality of hour characters N are provided on the radially outer edge of the dial 31. The wristwatch 1 of this embodiment has twelve hour characters N, from hour character N1 located at the 1 o'clock position to hour character N12 located at the 12 o'clock position. The twelve hour characters N are arranged at equal intervals along the circumferential direction centered on the rotation axis 3x of the hands 3. The illustrated hour characters N are bar-shaped. The hour characters N extend in the radial direction centered on the rotation axis 3x.

[0017] As shown in FIG. 2, the solar panel 4 is arranged around the rotation axis 3x of the hand 3. The rotation axis 3x of the hand 3 is connected to a motor via a gear train and is driven to rotate by the motor. The operation of the motor is controlled by a control circuit. The control circuit outputs a drive signal using power from a battery 12, and the drive signal rotates the motor. The solar panel 4 in this embodiment has a substantially circular shape. The solar panel 4 is arranged coaxially with the rotation axis 3x. A through hole 4c corresponding to the rotation axis 3x is provided in the center of the solar panel 4. The rotation axis 3x is inserted through the through hole 4c.

[0018] The solar panel 4 includes a plurality of solar cells connected in series. The solar panel 4 illustrated in Fig. 2 has six solar cells. More specifically, the solar panel 4 has a first cell 5, a second cell 6, a third cell 7, a fourth cell 8, a fifth cell 9, and a sixth cell 10. The cells 5, 6, 7, 8, 9, and 10 are all solar cells that convert received light into electricity.

[0019] In the solar panel 4 of this embodiment, the multiple solar cells have the same light-receiving area. That is, the light-receiving area S1 of the first cell 5 is equal to the light-receiving areas Si (i=2, 3, 4, 5, 6) of the other five cells 6, 7, 8, 9, 10. In other words, the light-receiving areas Si (i=1, 2, 3, 4, 5, 6) of the six cells 5, 6, 7, 8, 9, 10 are all the same value.

[0020] The solar panel 4 has a first side E1 and a second side E2, bounded by an imaginary line IL. As shown in FIG. 1 , the imaginary line IL is a straight line connecting twelve o'clock and six o'clock on the wristwatch 1. The imaginary line IL passes through the center line of the twelve o'clock hour symbol N12 and the center line of the six o'clock hour symbol N6. The imaginary line IL extends in the direction in which the two lugs 22 protrude from the case body 21. The first side E1 is on the nine o'clock side of the imaginary line IL. The second side E2 is on the three o'clock side of the imaginary line IL. The imaginary line IL is perpendicular to the rotation axis 3x of the hands 3 and is, for example, a straight line that bisects the dial 31 when viewed from the front.

[0021] On the imaginary line IL, the first cell 5, second cell 6, third cell 7, fourth cell 8, fifth cell 9, and sixth cell 10 are arranged in this order from the twelve o'clock position to the six o'clock position. Of these, the first cell 5, second cell 6, and third cell 7 are arranged on the twelve o'clock side of the rotation axis 3x. The fourth cell 8, fifth cell 9, and sixth cell 10 are arranged on the six o'clock side of the rotation axis 3x. The six cells 5, 6, 7, 8, 9, and 10 are connected in series in this order, for example.

[0022] As will be described below, each of the cells 5, 6, 7, 8, 9, and 10 of this embodiment has a light receiving portion on both the first side E1 and the second side E2. Therefore, the solar panel 4 of this embodiment can generate electricity even if either the light receiving portion on the first side E1 or the light receiving portion on the second side E2 is shaded.

[0023] As shown in FIG. 2, the first cell 5 has a first region 51 and a second region 52. The first region 51 is disposed on a first side E1 with respect to the imaginary line IL. The second region 52 is disposed on a second side E2 with respect to the imaginary line IL. The first region 51 has a light-receiving area S11. The second region 52 has a light-receiving area S12. The light-receiving areas S of the two regions 51 and 52 are equal. That is, the shape and arrangement of the first cell 5 are set so that the following formula (1) is established. S11=S12 (1)

[0024] The second cell 6 has a first region 61 disposed on a first side E1 with respect to the imaginary line IL, and a second region 62 disposed on a second side E2 with respect to the imaginary line IL. The first region 61 has a light-receiving area S21. The second region 62 has a light-receiving area S22. As shown in the following formula (2), the light-receiving areas S of the two regions 61 and 62 are equal. S21=S22 (2)

[0025] The third cell 7 has a first region 71 disposed on a first side E1 with respect to the imaginary line IL, and a second region 72 disposed on a second side E2 with respect to the imaginary line IL. The first region 71 has a light-receiving area S31. The second region 72 has a light-receiving area S32. As shown in the following formula (3), the light-receiving areas S of the two regions 71 and 72 are equal. S31=S32 (3)

[0026] The fourth cell 8 has a first region 81 disposed on a first side E1 of the imaginary line IL and a second region 82 disposed on a second side E2 of the imaginary line IL. The first region 81 has a light-receiving area S41. The second region 82 has a light-receiving area S42. As shown in the following formula (4), the light-receiving areas S of the two regions 81 and 82 are equal. S41=S42 (4)

[0027] The fifth cell 9 has a first region 91 disposed on a first side E1 of the imaginary line IL and a second region 92 disposed on a second side E2 of the imaginary line IL. The first region 91 has a light-receiving area S51. The second region 92 has a light-receiving area S52. As shown in the following formula (5), the light-receiving areas S of the two regions 91 and 92 are equal. S51=S52 (5)

[0028] The sixth cell 10 has a first region 101 disposed on a first side E1 with respect to the imaginary line IL, and a second region 102 disposed on a second side E2 with respect to the imaginary line IL. The first region 101 has a light-receiving area S61. The second region 102 has a light-receiving area S62. As shown in the following formula (6), the light-receiving areas S of the two regions 101 and 102 are equal. S61=S62 (6)

[0029] In the solar panel 4 illustrated in Fig. 2, the first cell 5, the second cell 6, the fifth cell 9, and the sixth cell 10 have shapes that are line-symmetric with respect to the imaginary line IL. However, the shapes of the cells 5, 6, 9, and 10 are not limited to line-symmetric shapes. The third cell 7 and the fourth cell 8 in Fig. 2 have the same shape. The shape of the fourth cell 8 is equal to the shape obtained when the third cell 7 is rotated 180 degrees around the rotation axis 3x.

[0030] The solar panel 4 has a boundary line Bj (j=1, 2, 3, 4, 5) between two adjacent solar cells. For example, the solar panel 4 has a first boundary line B1 that is a boundary line between the first cell 5 and the second cell 6. The first boundary line B1 may be a small gap between the first cell 5 and the second cell 6. The solar panel 4 also has a second boundary line B2, a third boundary line B3, a fourth boundary line B4, and a fifth boundary line B5. The second boundary line B2 is a boundary line between the second cell 6 and the third cell 7, and the third boundary line B3 is a boundary line between the third cell 7 and the fourth cell 8. The fourth boundary line B4 is a boundary line between the fourth cell 8 and the fifth cell 9, and the fifth boundary line B5 is a boundary line between the fifth cell 9 and the sixth cell 10.

[0031] Each of the boundary lines B1, B2, B3, B4, and B5 has a first end and a second end. For example, the first boundary line B1 has a first end B11 and a second end B12. The first end B11 is the end of the first boundary line B1 on the nine o'clock side. The second end B12 is the end of the first boundary line B1 on the three o'clock side. The first boundary line B1 extends from the first end B11 to the second end B12. The first boundary line B1 extends while curving between the first end B11 and the second end B12.

[0032] The second boundary line B2 has a first end B21 on the nine o'clock side and a second end B22 on the three o'clock side. The third boundary line B3 has a first end B31 on the nine o'clock side and a second end B32 on the three o'clock side. The fourth boundary line B4 has a first end B41 on the nine o'clock side and a second end B42 on the three o'clock side. The fifth boundary line B5 has a first end B51 on the nine o'clock side and a second end B52 on the three o'clock side. Each of the boundary lines B2, B3, B4, and B5 extends while curving between the first end and the second end.

[0033] In the solar panel 4 of this embodiment, at one boundary line Bj, the first end and the second end are arranged in positions facing each other with the imaginary line IL in between. For example, at the first boundary line B1, the first end B11 and the second end B12 are arranged in positions facing each other with the imaginary line IL in between. Similarly, at the second boundary line B2, the first end B21 and the second end B22 are arranged in positions facing each other with the imaginary line IL in between. At the other boundary lines B3, B4, and B5, the first end B31, B41, and B51 and the second end B32, B42, and B52 are arranged in positions facing each other with the imaginary line IL in between.

[0034] As described above, by arranging the first end and the second end of one boundary line Bj so that they face each other with the imaginary line IL in between, it is possible to reduce the total length of the boundary line Bj. It is also possible to prevent the shape of each solar cell from becoming complicated. Furthermore, it is less likely that an increase in resistance will occur in each solar cell due to the formation of narrow portions.

[0035] In the solar panel 4 of this embodiment, the first end and the second end are disposed at positions that are line-symmetrical with respect to the imaginary line IL at one boundary line Bj. For example, at the first boundary line B1, the positions of the first end B11 and the second end B12 are line-symmetrical with respect to the imaginary line IL. Similarly, at the other boundary lines Bj (j=2, 3, 4, 5), the positions of the first end B21, B31, B41, B51 and the second end B22, B32, B42, B52 are line-symmetrical with respect to the imaginary line IL.

[0036] The above-described arrangement of the two ends makes it difficult for bias in the light-receiving area of ​​the solar cell to occur, as will be explained below with reference to Figure 3. Figure 3 shows the positional relationship between each end of the boundary line Bj and the hour character N. In the first boundary line B1, the first end B11 overlaps with the hour character N11 at eleven o'clock. The second end B12 of the first boundary line B1 is located in a position symmetrical to the first end B11 with respect to the imaginary line IL, and overlaps with the hour character N1 at one o'clock. This makes it difficult for bias in the light-receiving area of ​​the first cell 5 and the second cell 6 to occur.

[0037] For example, in the first region 51 of the first cell 5, the light is blocked by the hour character N11 in the portion overlapping with the hour character N11, reducing the amount of light received. Similarly, in the second region 52 of the first cell 5, the amount of power generated is reduced in the portion overlapping with the hour character N1. Therefore, it is unlikely that a large difference will occur between the effective value of the light-receiving area in the first region 51 and the effective value of the light-receiving area in the second region 52.

[0038] For example, when the user wears the watch on the left hand and the first region 51 is blocked by the user's sleeve, the second region 52 generates power. On the other hand, when the user wears the watch on the right hand and the second region 52 is blocked by the user's sleeve, the first region 51 generates power. Because the difference in the effective light-receiving areas of the two regions 51 and 52 is small, even if either of the two regions 51 and 52 is blocked, there is unlikely to be a large difference in the amount of power generated by the first cell 5. This maximizes the power generation capacity of the first cell 5. The same is true for the second cell 6, where there is unlikely to be a large difference in the effective light-receiving areas between the first region 61 and the second region 62.

[0039] The first end B11 overlaps with the hour character N11 while extending in the radial direction centered on the rotation axis 3x. Furthermore, the second end B12 overlaps with the hour character N1 while extending in the radial direction centered on the rotation axis 3x. By arranging the boundary line B1 in a position shielded by the hour characters N1 and N11 in this way, the decrease in the power generation capacity of the two cells 5 and 6 is suppressed. The first end B11 extends radially and overlaps with the hour character N11, which reduces the difference in light receiving area between the two first regions 51 and 61. Similarly, the second end B12 extends radially and overlaps with the hour character N1, which reduces the difference in light receiving area between the two second regions 52 and 62.

[0040] At the second boundary line B2, the first end B21 overlaps with the ten o'clock character N10. The second end B22, which is positioned symmetrically with the line, overlaps with the two o'clock character N2. At the third boundary line B3, the first end B31 overlaps with the nine o'clock character N9. The second end B32, which is positioned symmetrically with the line, overlaps with the three o'clock character N3. At the fourth boundary line B4, the first end B41 overlaps with the eight o'clock character N8. The second end B42, which is positioned symmetrically with the line, overlaps with the four o'clock character N4. At the fifth boundary line B5, the first end B51 overlaps with the seven o'clock character N7. The second end B52, which is positioned symmetrically with the line, overlaps with the five o'clock character N5.

[0041] With the above-described arrangement, a large difference in the effective light-receiving area between the first regions 61, 71, 81, 91, 101 and the second regions 62, 72, 82, 92, 102 in each cell 6 is unlikely to occur.

[0042] Furthermore, each of the first ends B21, B41, and B51 extends in a radial direction centered on the rotation axis 3x and overlaps with the corresponding hour character N. This makes it difficult for differences to occur in the effective values ​​of the light-receiving areas between the two first regions 61 and 71, between the two first regions 81 and 91, and between the two first regions 91 and 101.

[0043] Each second end B22, B42, B52 extends in the radial direction and overlaps with the corresponding hour letter N. This makes it difficult for differences to occur in the effective light-receiving area between the two second regions 62, 72, between the two second regions 82, 92, and between the two second regions 92, 102.

[0044] In the third boundary line B3, the first end B31 overlaps with the nine o'clock character N9, but the extending direction is different from the radial direction. The second end B32 overlaps with the three o'clock character N3, but the extending direction is different from the radial direction.

[0045] The nine o'clock hour character N9 mainly overlaps with the first region 81 of the fourth cell 8. In this case, the shape of the fourth cell 8 may be designed so that the following formula (7) holds. In the following formula (7), S40 is the total area of ​​the first region 81, and S4d is the area of ​​the portion of the first region 81 that overlaps with the nine o'clock hour character N9. In other words, the light receiving area S41 of the first region 81 may be the area of ​​the portion of the total area S40 of the first region 81 that does not overlap with the nine o'clock hour character N9. S41=S40-S4d=S42 (7)

[0046] The three o'clock character N3 mainly overlaps with the second region 72 of the third cell 7. In this case, the shape of the third cell 7 may be designed so that the following formula (8) holds. In the following formula (8), S30 is the total area of ​​the second region 72, and S3d is the area of ​​the portion of the second region 72 that overlaps with the three o'clock character N3. In other words, the light receiving area S32 of the second region 72 may be the area of ​​the portion of the total area S30 of the second region 72 that does not overlap with the three o'clock character N3. S32=S30-S3d=S31 (8)

[0047] In the solar panel 4 of this embodiment, the first ends B11, B21, B31, B41, and B51 are arranged to equally divide the outer periphery of the dial 31 on the nine o'clock side of the imaginary line IL. In other words, in the dial 31, the outer periphery of the first side E1 on the imaginary line IL is divided into six equal parts by the five first ends B11, B21, B31, B41, and B51.

[0048] The second end portions B12, B22, B32, B42, and B52 are arranged to equally divide the outer circumference of the dial 31 on the 3 o'clock side of the imaginary line IL. In other words, on the dial 31, the outer circumference of the second side E2 on the imaginary line IL is divided into six equal parts by the five second end portions B12, B22, B32, B42, and B52.

[0049] Dividing the outer periphery of the dial 31 into equal parts has the following effects, for example. Figure 4 shows a wristwatch 1 having divisions M. The divisions M are marks placed on the dial 31 and are formed, for example, by printing. The divisions M are placed between adjacent hour characters N to indicate the position of each minute. In other words, four divisions M are placed between each two adjacent hour characters N.

[0050] By dividing the periphery equally by the boundary lines Bj, the number of segments M overlapping each solar cell is less likely to vary. For example, in the solar panel 4 shown in Fig. 4, four segments M overlap the first region 51 of the first cell 5, and four segments M also overlap the second region 52. In other words, eight segments M overlap the first cell 5. Similarly, four segments M each overlap the two regions 61 and 62 of the second cell 6, and four segments M each overlap the two regions 71 and 72 of the third cell 7.

[0051] In this way, eight segments M are distributed across all solar cells. By having an equal number of segments M overlapping each solar cell, variations in the effective light-receiving area of ​​the solar cells are less likely to occur. Note that the effect of equally dividing the outer periphery of the dial 31 is not limited to when the wristwatch 1 has segments M. For example, a similar effect can be expected when various decorations or markings are arranged around the dial 31.

[0052] Furthermore, in the wristwatch 1 of this embodiment, the solar cell has a shape that reduces the impact of light being blocked by the hands 3. If the shadow of the hands 3 is concentrated on one solar cell, the amount of power generated by the solar panel 4 is likely to decrease. As will be explained below, the solar panel 4 of this embodiment makes it possible to distribute the shadow of the hands 3 across multiple solar cells.

[0053] As shown in FIG. 5, the second region 52 of the first cell 5 has a protruding portion 52p that protrudes toward the second cell 6. The illustrated protruding portion 52p has a shape that is convex in the clockwise direction CW toward the second region 62 of the second cell 6. The tip of the protruding portion 52p is curved in a substantially arc-like shape. The first boundary line B1 has a curved portion B13 that is curved so that the first cell 5 has the protruding portion 52p. The curved portion B13 is curved in a substantially arc-like shape.

[0054] FIG. 5 shows a dashed line R1. The line R1 connects the second end B12 of the first boundary line B1 and the rotation axis 3x of the pointer 3. More specifically, the line R1 extends radially from the central axis of the rotation axis 3x toward the second end B12. The protrusion 52p protrudes toward the second cell 6 with respect to the line R1. Therefore, the curved portion B13 of the first boundary line B1 intersects with the line R1. The protrusion 52p is an area that extends beyond the line R1 toward the second cell 6.

[0055] By providing the protrusion 52p described above, the shadow of the hand 3 is less likely to be concentrated on one solar cell. Figure 6 shows the hand 3 positioned between 12 o'clock and 1 o'clock. In this case, the hand 3 overlaps with three cells 5, 6, and 7. In other words, the influence of the shadow of the hand 3 is dispersed among the three cells 5, 6, and 7.

[0056] FIG. 7 shows the pointer 3 overlapping the protrusion 52p. The pointer 3 is positioned slightly past its temporary rotation position. The middle portion of the pointer 3 in the longitudinal direction overlaps the protrusion 52p. Therefore, the pointer 3 overlaps with the three cells 5, 6, and 7. As a result, the shadow of the pointer 3 is dispersed among the three cells 5, 6, and 7, and a decrease in the amount of power generated by the solar panel 4 is suppressed.

[0057] As a comparative example, consider a case where the second region 52 of the first cell 5 does not have a protruding portion 52p. In this case, the second region 52 is formed so that no portion extends beyond the straight line R1 in FIG. 5. In the comparative example, most of the pointer 3 located in the position shown in FIG. 7 overlaps with the second cell 6. In other words, the shadow of the pointer 3 is concentrated on the second cell 6. As a result, a decrease in the amount of power generated by the solar panel 4 is likely to occur. In contrast, with the solar panel 4 of this embodiment having the protruding portion 52p, a decrease in the amount of power generated by the solar panel 4 is less likely to occur.

[0058] As shown in FIG. 2, the first region 51 of the first cell 5 has a protrusion 51p similar to the protrusion 52p. The protrusion 51p protrudes counterclockwise toward the first region 61 of the second cell 6. The first boundary line B1 has a curved portion B14 corresponding to the protrusion 51p. The curved portion B14 protrudes toward the second cell 6 while intersecting with a straight line connecting the first end B11 of the first boundary line B1 and the rotation axis 3x. The protrusion 51p can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL.

[0059] Next, the protrusion of the second cell 6 will be described. As shown in FIG. 8, the second region 62 of the second cell 6 has a protrusion 62p that protrudes toward the third cell 7. The illustrated protrusion 62p has a shape that is convex in the clockwise direction CW toward the second region 72 of the third cell 7. The tip of the protrusion 62p is curved in a substantially arc shape. The second boundary line B2 has a curved portion B23 that is curved so that the second cell 6 has the protrusion 62p. The curved portion B23 is curved in a substantially arc shape.

[0060] FIG. 8 shows a dashed line R2. The line R2 connects the second end B22 of the second boundary line B2 and the rotation axis 3x of the pointer 3. The protrusion 62p protrudes toward the third cell 7 with respect to the line R2. Therefore, the curved portion B23 of the second boundary line B2 intersects with the line R2. The protrusion 62p is an area that extends beyond the line R2 toward the third cell 7.

[0061] FIG. 9 shows the pointer 3 positioned so as to overlap the protrusion 62p of the second cell 6. The pointer 3 is positioned slightly past the two o'clock rotation position. The middle portion of the pointer 3 in the longitudinal direction overlaps the protrusion 62p. Therefore, the pointer 3 overlaps with at least two cells 6 and 7. As a result, the shadow of the pointer 3 is dispersed over at least two cells 6 and 7, and a decrease in the amount of power generated by the solar panel 4 is suppressed.

[0062] As a comparative example, consider a case where the second cell 6 does not have the protrusion 62p. In this case, almost the entire pointer 3 positioned as shown in FIG. 9 overlaps with the second cell 6. In other words, the shadow of the pointer 3 is concentrated on the second cell 6. As a result, a decrease in the amount of power generated by the solar panel 4 is likely to occur. In contrast, in the solar panel 4 of this embodiment, the protrusion 62p suppresses the decrease in the amount of power generated.

[0063] As shown in FIG. 2, the first region 61 of the second cell 6 has a protrusion 61p similar to the protrusion 62p. The protrusion 61p protrudes counterclockwise toward the first region 71 of the third cell 7. The second boundary line B2 has a curved portion B24 corresponding to the protrusion 61p. The curved portion B24 protrudes toward the third cell 7 while intersecting with a straight line connecting a first end B21 of the second boundary line B2 and the rotation axis 3x. The protrusion 61p can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL.

[0064] Next, the protrusion of the third cell 7 will be described. As shown in FIG. 10, the second region 72 of the third cell 7 has a protrusion 72p that protrudes toward the fourth cell 8. The illustrated protrusion 72p has a shape that is convex in the clockwise direction CW toward the second region 82 of the fourth cell 8. The tip of the protrusion 72p is curved in a substantially arc-like shape. The third boundary line B3 has a curved portion B33 that is curved so that the third cell 7 has the protrusion 72p. The curved portion B33 is curved in a substantially arc-like shape.

[0065] FIG. 10 shows a dashed dotted line R3. The line R3 connects the second end B32 of the third boundary line B3 and the rotation axis 3x of the pointer 3. The protruding portion 72p protrudes toward the fourth cell 8 with respect to the line R3. Therefore, the curved portion B33 of the third boundary line B3 intersects with the line R3. The protruding portion 72p is an area that extends beyond the line R3 toward the fourth cell 8.

[0066] FIG. 11 shows the pointer 3 positioned so that it overlaps the protrusion 72p of the third cell 7. The position of the pointer 3 at this time is slightly past the three o'clock rotation position. The tip end portion of the pointer 3 overlaps the protrusion 72p. In addition, the base end portion of the pointer 3 overlaps the fourth cell 8. Therefore, the pointer 3 overlaps with at least two cells 7 and 8. As a result, the shadow of the pointer 3 is dispersed over at least two cells 7 and 8, and a decrease in the amount of power generated by the solar panel 4 is suppressed.

[0067] As shown in FIG. 2, the first region 81 of the fourth cell 8 has a protrusion 81p similar to the protrusion 72p. The protrusion 81p protrudes clockwise (CW) toward the first region 71 of the third cell 7. The third boundary line B3 has a curved portion B34 corresponding to the protrusion 81p of the fourth cell 8. The curved portion B34 protrudes toward the third cell 7 while intersecting with a straight line connecting the first end B31 of the third boundary line B3 and the rotation axis 3x. The protrusion 81p can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL.

[0068] Next, the protrusion of the fifth cell 9 will be described. As shown in FIG. 12, the second region 92 of the fifth cell 9 has a protrusion 92p that protrudes toward the fourth cell 8. The illustrated protrusion 92p has a shape that is convex in the counterclockwise direction (CCW) toward the second region 82 of the fourth cell 8. The tip of the protrusion 92p is curved in a substantially arc-like shape. The fourth boundary line B4 has a curved portion B43 that is curved so that the fifth cell 9 has the protrusion 92p. The curved portion B43 is curved in a substantially arc-like shape.

[0069] FIG. 12 shows a dashed dotted line R4. The line R4 connects the second end B42 of the fourth boundary line B4 and the rotation axis 3x of the pointer 3. The protrusion 92p protrudes toward the fourth cell 8 with respect to the line R4. Therefore, the curved portion B43 of the fourth boundary line B4 intersects with the line R4. The protrusion 92p is an area that extends beyond the line R4 toward the fourth cell 8.

[0070] FIG. 13 shows the hand 3 overlapping the protrusion 92p of the fifth cell 9. The hand 3 is positioned slightly forward of the four o'clock position. The longitudinal middle of the hand 3 overlaps the protrusion 92p. The base and tip of the hand 3 overlap the fourth cell 8. Therefore, the hand 3 overlaps at least two cells 8 and 9. As a result, the shadow of the hand 3 is dispersed across at least two cells 8 and 9, minimizing the reduction in the amount of power generated by the solar panel 4. The protrusion 92p, which bulges counterclockwise (CCW), also contributes to ensuring the necessary light-receiving area of ​​the fifth cell 9 to equalize the light-receiving areas of the cells 5, 6, 7, 8, 9, and 10.

[0071] As shown in FIG. 2, the first region 91 of the fifth cell 9 has a protrusion 91p similar to the protrusion 92p. The protrusion 91p protrudes counterclockwise toward the first region 81 of the fourth cell 8. The fourth boundary line B4 has a curved portion B44 corresponding to the protrusion 91p of the fifth cell 9. The curved portion B44 protrudes toward the fourth cell 8 while intersecting with a straight line connecting a first end B41 of the fourth boundary line B4 and the rotation axis 3x. The protrusion 91p can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL.

[0072] Next, the protrusion of the sixth cell 10 will be described. As shown in FIG. 14, the second region 102 of the sixth cell 10 has a protrusion 102p that protrudes toward the fifth cell 9. The illustrated protrusion 102p has a shape that is convex in the counterclockwise direction (CCW) toward the second region 92 of the fifth cell 9. The tip of the protrusion 102p is curved in a substantially arc-like shape. The fifth boundary line B5 has a curved portion B53 that is curved so that the sixth cell 10 has the protrusion 102p. The curved portion B53 is curved in a substantially arc-like shape.

[0073] FIG. 14 shows a dashed line R5. The line R5 connects the second end B52 of the fifth boundary line B5 and the rotation axis 3x of the pointer 3. The protrusion 102p protrudes toward the fifth cell 9 with respect to the line R5. Therefore, the curved portion B53 of the fifth boundary line B5 intersects with the line R5. The protrusion 102p is an area that extends beyond the line R5 toward the fifth cell 9.

[0074] FIG. 15 shows the hand 3 overlapping the protrusion 102p of the sixth cell 10. The hand 3 is positioned slightly forward of the five o'clock position. The middle portion of the hand 3 in the longitudinal direction overlaps the protrusion 102p. The base end of the hand 3 overlaps two cells 8 and 9, and the tip end of the hand 3 overlaps the fifth cell 9. Therefore, the hand 3 overlaps at least three cells 9 and 10. As a result, the shadow of the hand 3 is dispersed across at least three cells 9 and 10, suppressing a decrease in the amount of power generated by the solar panel 4. The protrusion 102p, which bulges counterclockwise (CCW), also contributes to ensuring the necessary light-receiving area of ​​the sixth cell 10 to equalize the light-receiving areas of the cells 5, 6, 7, 8, 9, and 10.

[0075] As shown in FIG. 2, the first region 101 of the sixth cell 10 has a protrusion 101p similar to the protrusion 102p. The protrusion 101p protrudes clockwise toward the first region 91 of the fifth cell 9. The fifth boundary line B5 has a curved portion B54 corresponding to the protrusion 101p of the sixth cell 10. The curved portion B54 protrudes toward the fifth cell 9 while intersecting with a straight line connecting a first end B51 of the fifth boundary line B5 and the rotation axis 3x. The protrusion 101p can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL.

[0076] The number of solar cells in the solar panel 4 is not limited to six. The solar panel 4 may be composed of five solar cells, as shown in FIG. 16. The solar panel 4 in FIG. 16 has a first cell 5, a second cell 6, a third cell 7, a fourth cell 8, and a fifth cell 9. The five cells 5, 6, 7, 8, and 9 are connected in series. The light-receiving area S1 of the first cell 5 is equal to the light-receiving areas Si (i=2, 3, 4, 5) of the other four cells 6, 7, 8, and 9. In other words, the light-receiving areas Si (i=1, 2, 3, 4, 5) of the five cells 5, 6, 7, 8, and 9 are all the same value.

[0077] On the imaginary line IL, a first cell 5, a second cell 6, a third cell 7, a fourth cell 8, and a fifth cell 9 are arranged in this order from the twelve o'clock position to the six o'clock position.

[0078] The first cell 5 has a first region 51 arranged on a first side E1 with respect to the imaginary line IL and a second region 52 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 51 and 52 are equal. The second cell 6 has a first region 61 arranged on a first side E1 with respect to the imaginary line IL and a second region 62 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 61 and 62 are equal.

[0079] The third cell 7 has a first region 71 arranged on a first side E1 with respect to the imaginary line IL and a second region 72 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 71 and 72 are equal. The fourth cell 8 has a first region 81 arranged on a first side E1 with respect to the imaginary line IL and a second region 82 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 81 and 82 are equal. The fifth cell 9 has a first region 91 arranged on a first side E1 with respect to the imaginary line IL and a second region 92 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 91 and 92 are equal.

[0080] 16, all of the cells 5, 6, 7, 8, and 9 have shapes that are line-symmetric with respect to the imaginary line IL. However, the shapes of the cells 5, 6, 7, 8, and 9 are not limited to line-symmetric shapes.

[0081] At the first boundary line B1, the first end B11 and the second end B12 are positioned opposite each other with the imaginary line IL in between. The same is true for the other boundary lines B2, B3, and B4, where the first end parts B21, B31, and B41 are positioned opposite the second end parts B22, B32, and B42, respectively, with the imaginary line IL in between. The first end parts B11, B21, B31, and B41 may be positioned symmetrically to the second end parts B12, B22, B32, and B42 with respect to the imaginary line IL.

[0082] When any of the first ends B11, B21, B31, and B41 is positioned so as to overlap the hour character N, the corresponding second end B12, B22, B32, and B42 may also be positioned so as to overlap the hour character N. For example, when the first end B11 of the first boundary line B1 overlaps the hour character N, the corresponding second end B12 may also be positioned so as to overlap the hour character N.

[0083] The four first end portions B11, B21, B31, and B41 are arranged, for example, as shown in FIG. 16 , to equally divide the outer periphery of the dial 31 on the nine o'clock side of the imaginary line IL. In this case, one hour character N can be arranged in each of the five first regions 51, 61, 71, 81, and 91. The four second end portions B12, B22, B32, and B42 are arranged, for example, to equally divide the outer periphery of the dial 31 on the three o'clock side of the imaginary line IL. In this case, one hour character N can be arranged in each of the five second regions 52, 62, 72, 82, and 92. In the first cell 5, a twelve o'clock character N12 is arranged at the boundary between the first region 51 and the second region 52. In the fifth cell 9, a six o'clock character N6 is arranged at the boundary between the first region 91 and the second region 92.

[0084] The first cell 5 has two protrusions 51p, 52p. The protrusion 51p is part of the first region 51 and protrudes toward the first region 61 of the second cell 6. The first boundary line B1 has a curved portion B14 that curves so that the first cell 5 has the protrusion 51p. The curved portion B14 protrudes toward the second cell 6 while intersecting with the straight line connecting the first end B11 and the rotation axis 3x.

[0085] The protruding portion 52p is a part of the second region 52 and protrudes toward the second region 62 of the second cell 6. The first boundary line B1 has a curved portion B13 that is curved so that the first cell 5 has the protruding portion 52p. The curved portion B13 protrudes toward the second cell 6 while intersecting with the straight line connecting the second end B12 and the rotation axis 3x.

[0086] The second cell 6 has two protrusions 61p, 62p. The protrusion 61p is part of the first region 61 and protrudes toward the first region 71 of the third cell 7. The second boundary line B2 has a curved portion B24 that curves so that the second cell 6 has the protrusion 61p. The curved portion B24 protrudes toward the third cell 7 while intersecting with a straight line connecting the first end B21 of the second boundary line B2 and the rotation axis 3x.

[0087] The protruding portion 62p is a part of the second region 62 and protrudes toward the second region 72 of the third cell 7. The second boundary line B2 has a curved portion B23 that is curved so that the second cell 6 has the protruding portion 62p. The curved portion B23 protrudes toward the third cell 7 while intersecting with the straight line connecting the second end B22 and the rotation axis 3x.

[0088] The fourth cell 8 has two protrusions 81p, 82p. The protrusion 81p is part of the first region 81 and protrudes toward the first region 71 of the third cell 7. The third boundary line B3 has a curved portion B34 that curves so that the fourth cell 8 has the protrusion 81p. The curved portion B34 protrudes toward the third cell 7 while intersecting with a straight line connecting the first end B31 of the third boundary line B3 and the rotation axis 3x.

[0089] The protruding portion 82p is a part of the second region 82 and protrudes toward the second region 72 of the third cell 7. The third boundary line B3 has a curved portion B33 that is curved so that the fourth cell 8 has the protruding portion 82p. The curved portion B33 protrudes toward the third cell 7 while intersecting with a straight line connecting the second end B32 of the third boundary line B3 and the rotation axis 3x.

[0090] The fifth cell 9 has two protrusions 91p, 92p. The protrusion 91p is part of the first region 91 and protrudes toward the first region 81 of the fourth cell 8. The fourth boundary line B4 has a curved portion B44 that curves so that the fifth cell 9 has the protrusion 91p. The curved portion B44 protrudes toward the fourth cell 8 while intersecting with a straight line connecting the first end B41 of the fourth boundary line B4 and the rotation axis 3x.

[0091] The protruding portion 92p is part of the second region 92 and protrudes toward the second region 82 of the fourth cell 8. The fourth boundary line B4 has a curved portion B43 that is curved so that the fifth cell 9 has the protruding portion 92p. The curved portion B43 protrudes toward the fourth cell 8 while intersecting with a straight line connecting the second end B42 of the fourth boundary line B4 and the rotation axis 3x.

[0092] The solar panel 4 in Fig. 16 has curved portions B14, B24, B34, and B44, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL. Also, the solar panel 4 in Fig. 16 has curved portions B13, B23, B33, and B43, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the second side E2 with respect to the imaginary line IL.

[0093] The solar panel 4 may be configured with four solar cells, as shown in FIG. 17. The solar panel 4 in FIG. 17 has a first cell 5, a second cell 6, a third cell 7, and a fourth cell 8. The four cells 5, 6, 7, and 8 are connected in series. The light-receiving area S1 of the first cell 5 is equal to the light-receiving areas Si (i=2, 3, 4) of the other three cells 6, 7, and 8. In other words, the light-receiving areas Si (i=1, 2, 3, 4) of the four cells 5, 6, 7, and 8 are all the same value.

[0094] On the imaginary line IL, a first cell 5, a second cell 6, a third cell 7, and a fourth cell 8 are arranged in this order from the twelve o'clock position to the six o'clock position.

[0095] The first cell 5 has a first region 51 arranged on a first side E1 with respect to the imaginary line IL and a second region 52 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 51 and 52 are equal. The second cell 6 has a first region 61 arranged on a first side E1 with respect to the imaginary line IL and a second region 62 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 61 and 62 are equal.

[0096] The third cell 7 has a first region 71 disposed on a first side E1 with respect to the imaginary line IL and a second region 72 disposed on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 71 and 72 are equal. The fourth cell 8 has a first region 81 disposed on a first side E1 with respect to the imaginary line IL and a second region 82 disposed on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 81 and 82 are equal.

[0097] 17, the first cell 5 and the fourth cell 8 have shapes that are line-symmetric with respect to the imaginary line IL. However, the shapes of the first cell 5 and the fourth cell 8 are not limited to line-symmetric shapes. The second cell 6 and the third cell 7 have the same shape.

[0098] At the first boundary line B1, the first end B11 and the second end B12 are positioned opposite each other with the imaginary line IL in between. The same applies to the other boundary lines B2 and B3, where the first end B21 and B31 are positioned opposite each other with the imaginary line IL in between, the second end B22 and B32, respectively. The first end B11, B21, and B31 may be positioned symmetrically to the second end B12, B22, and B32 with respect to the imaginary line IL.

[0099] When any of the first ends B11, B21, B31 is positioned so as to overlap the hour character N, the corresponding second end B12, B22, B32 may also be positioned so as to overlap the hour character N. For example, when the first end B21 of the second boundary line B2 overlaps the hour character N, the corresponding second end B22 may also be positioned so as to overlap the hour character N.

[0100] The three first end portions B11, B21, and B31 are arranged, for example, as shown in FIG. 17 , so as to equally divide the outer periphery of the dial 31 on the nine o'clock side of the imaginary line IL. In this case, at least one hour character N can be arranged in each of the four first regions 51, 61, 71, and 81. The three second end portions B12, B22, and B32 are arranged, for example, so as to equally divide the outer periphery of the dial 31 on the three o'clock side of the imaginary line IL. In this case, at least one hour character N can be arranged in each of the four second regions 52, 62, 72, and 82. In the first cell 5, a twelve o'clock character N12 is arranged at the boundary between the first region 51 and the second region 52. In the fourth cell 8, a six o'clock character N6 is arranged at the boundary between the first region 81 and the second region 82.

[0101] The first cell 5 in Fig. 17 has two protruding portions 51p and 52p, similar to the first cell 5 in Fig. 16. The first boundary line B1 has two curved portions B14 and B13 corresponding to the two protruding portions 51p and 52p. The curved portion B14 protrudes toward the second cell 6 while intersecting with a straight line connecting the first end B11 of the second boundary line B2 and the rotation axis 3x. The curved portion B13 protrudes toward the second cell 6 while intersecting with a straight line connecting the second end B12 of the second boundary line B2 and the rotation axis 3x.

[0102] The second cell 6 has one protrusion 62p. The protrusion 62p is part of the second region 62 and protrudes toward the second region 72 of the third cell 7. The protrusion 62p has a shape that is convex in the clockwise CW direction. The second boundary line B2 has a curved portion B23 that is curved so that the second cell 6 has the protrusion 62p. The curved portion B23 protrudes toward the third cell 7 while intersecting with a straight line connecting the second end B22 of the second boundary line B2 and the rotation axis 3x.

[0103] The third cell 7 has one protrusion 71p. The protrusion 71p is part of the first region 71 and protrudes toward the first region 61 of the second cell 6. The protrusion 71p has a shape that is convex in the clockwise CW direction. The second boundary line B2 has a curved portion B24 that is curved so that the third cell 7 has the protrusion 71p. The curved portion B24 protrudes toward the second cell 6 while intersecting a straight line connecting the first end B21 of the second boundary line B2 and the rotation axis 3x.

[0104] The fourth cell 8 in FIG. 17 has two protrusions 81p and 82p. The third boundary line B3 has two curved portions B34 and B33 corresponding to the two protrusions 81p and 82p. The protrusion 81p is part of the first region 81 and protrudes toward the first region 71 of the third cell 7. The protrusion 81p has a convex shape in the clockwise (CW) direction. The protrusion 82p is part of the second region 82 and protrudes toward the second region 72 of the third cell 7. The protrusion 82p has a convex shape in the counterclockwise (CCW) direction.

[0105] The curved portion B34 protrudes toward the third cell 7 while intersecting with a straight line connecting the first end B31 of the third boundary line B3 and the rotation axis 3x. The curved portion B33 protrudes toward the third cell 7 while intersecting with a straight line connecting the second end B32 of the third boundary line B3 and the rotation axis 3x.

[0106] The solar panel 4 in Fig. 17 has curved portions B14, B24, and B34, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 with respect to the imaginary line IL. Also, the solar panel 4 in Fig. 17 has curved portions B13, B23, and B33, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the second side E2 with respect to the imaginary line IL.

[0107] The solar panel 4 may be composed of three solar cells, as shown in FIG. 18. The solar panel 4 in FIG. 18 has a first cell 5, a second cell 6, and a third cell 7. The three cells 5, 6, and 7 are connected in series. The light-receiving area S1 of the first cell 5 is equal to the light-receiving areas Si (i=2, 3) of the other two cells 6 and 7. In other words, the light-receiving areas Si (i=1, 2, 3) of the three cells 5, 6, and 7 are all the same value.

[0108] On the imaginary line IL, the first cell 5, the second cell 6, and the third cell 7 are arranged in this order from the twelve o'clock position to the six o'clock position.

[0109] The first cell 5 has a first region 51 arranged on a first side E1 with respect to the imaginary line IL and a second region 52 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 51 and 52 are equal. The second cell 6 has a first region 61 arranged on a first side E1 with respect to the imaginary line IL and a second region 62 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 61 and 62 are equal. The third cell 7 has a first region 71 arranged on a first side E1 with respect to the imaginary line IL and a second region 72 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 71 and 72 are equal.

[0110] 18, all of the cells 5, 6, and 7 have shapes that are line-symmetric with respect to the imaginary line IL. However, the shapes of the cells 5, 6, and 7 are not limited to line-symmetric shapes.

[0111] In the first boundary line B1, the first end B11 and the second end B12 are disposed in positions facing each other with the imaginary line IL in between. The same applies to the second boundary line B2, where the first end B21 is disposed in a position facing the second end B22 with the imaginary line IL in between. The first end B11 and B21 may be disposed in positions symmetrical to the second end B12 and B22 with respect to the imaginary line IL.

[0112] When either of the first ends B11, B21 is positioned so as to overlap the hour character N, the corresponding second end B12, B22 may also be positioned so as to overlap the hour character N. For example, when the first end B11 of the first boundary line B1 overlaps the hour character N, the corresponding second end B12 may also be positioned so as to overlap the hour character N. Furthermore, when the first end B21 of the second boundary line B2 overlaps the hour character N, the corresponding second end B22 may also be positioned so as to overlap the hour character N.

[0113] 18, the first end B11 of the first boundary line B1 overlaps with the ten o'clock hour character N10, and the second end B12 overlaps with the two o'clock hour character N2. Furthermore, the first end B21 of the second boundary line B2 overlaps with the eight o'clock hour character N8, and the second end B22 overlaps with the four o'clock hour character N4. Each of the ends B11, B12, B21, and B22 may overlap with the corresponding hour character N while extending radially around the rotation axis 3x of the hands 3.

[0114] The first cell 5 in FIG. 18 has two protrusions 51p and 52p similar to the protrusions 61p and 62p of the second cell 6 in FIG. 2. The first boundary line B1 also has two curved portions B14 and B13 corresponding to the two protrusions 51p and 52p. The curved portion B13 is curved so that the first cell 5 has the protrusion 52p. The curved portion B13 protrudes toward the second cell 6 while intersecting with a straight line connecting the second end B12 of the first boundary line B1 and the rotation axis 3x. The curved portion B14 is curved so that the first cell 5 has the protrusion 51p. The curved portion B14 protrudes toward the second cell 6 while intersecting with a straight line connecting the first end B11 of the first boundary line B1 and the rotation axis 3x.

[0115] The third cell 7 in FIG. 18 has two protrusions 71p and 72p similar to the protrusions 91p and 92p of the fifth cell 9 in FIG. 2. The second boundary line B2 has two curved portions B24 and B23 corresponding to the two protrusions 71p and 72p. The curved portion B23 is curved so that the third cell 7 has the protrusion 72p. The curved portion B23 protrudes toward the second cell 6 while intersecting with a straight line connecting the second end B22 of the second boundary line B2 and the rotation axis 3x. The curved portion B24 is curved so that the third cell 7 has the protrusion 71p. The curved portion B24 protrudes toward the second cell 6 while intersecting with a straight line connecting the first end B21 of the second boundary line B2 and the rotation axis 3x.

[0116] The solar panel 4 in Fig. 18 has curved portions B14 and B24, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the first side E1 of the imaginary line IL. Also, the solar panel 4 in Fig. 18 has curved portions B13 and B23, which can suppress a decrease in the amount of power generated by the solar panel 4 when the pointer 3 is on the second side E2 of the imaginary line IL.

[0117] The solar panel 4 may be composed of two solar cells, as shown in Fig. 19. The solar panel 4 in Fig. 19 has a first cell 5 and a second cell 6. The two cells 5, 6 are connected in series. The light-receiving area of ​​the first cell 5 is equal to the light-receiving area of ​​the second cell 6. On the imaginary line IL, the first cell 5 and the second cell 6 are lined up in this order from the twelve o'clock position to the six o'clock position.

[0118] The first cell 5 has a first region 51 arranged on a first side E1 with respect to the imaginary line IL and a second region 52 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 51 and 52 are equal. The second cell 6 has a first region 61 arranged on a first side E1 with respect to the imaginary line IL and a second region 62 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 61 and 62 are equal.

[0119] 19, the two cells 5 and 6 have the same shape. However, the shapes of the first cell 5 and the second cell 6 are not limited to being the same shape.

[0120] In the first boundary line B1, the first end B11 and the second end B12 are positioned opposite each other with the imaginary line IL in between. The first end B11 may be positioned symmetrically to the second end B12 with respect to the imaginary line IL. When the first end B11 is positioned to overlap with the hour character N, the second end B12 may also be positioned to overlap with the hour character N. In the solar panel 4 of FIG. 19, the first end B11 of the first boundary line B1 overlaps with the hour character N9 at nine o'clock, and the second end B12 overlaps with the hour character N3 at three o'clock. The two ends B11, B12 may overlap with the corresponding hour character N while extending in a radial direction centered on the rotation axis 3x.

[0121] The first cell 5 in Fig. 19 has a protrusion 52p similar to the protrusion 72p of the third cell 7 in Fig. 2. The second cell 6 in Fig. 19 has a protrusion 61p similar to the protrusion 81p of the fourth cell 8 in Fig. 2. The two protrusions 52p, 61p have a shape that is convex in the clockwise (CW) direction.

[0122] The first boundary line B1 has a curved portion B13 corresponding to the protrusion 52p and a curved portion B14 corresponding to the protrusion 61p. The curved portion B14 protrudes toward the first cell 5 while intersecting with the straight line connecting the first end B11 and the rotation axis 3x. The curved portion B13 protrudes toward the second cell 6 while intersecting with the straight line connecting the second end B12 and the rotation axis 3x.

[0123] The shape of the solar cells may be set so that the time that the pointer 3 overlaps multiple solar cells can be extended. For example, as shown in Fig. 20, two curved portions B14, B16 may be provided on the first boundary line B1 between the first end B11 and the rotation axis 3x. For example, two curved portions B13, B15 may be provided on the first boundary line B1 between the rotation axis 3x and the second end B12.

[0124] The solar panel 4 in Figure 20 is composed of a first cell 5 and a second cell 6. The two cells 5, 6 are connected in series. The light-receiving area of ​​the first cell 5 is equal to the light-receiving area of ​​the second cell 6. On the imaginary line IL, the first cell 5 and the second cell 6 are lined up in this order from the twelve o'clock position to the six o'clock position.

[0125] The first cell 5 has a first region 51 arranged on a first side E1 with respect to the imaginary line IL and a second region 52 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 51 and 52 are equal. The second cell 6 has a first region 61 arranged on a first side E1 with respect to the imaginary line IL and a second region 62 arranged on a second side E2 with respect to the imaginary line IL. The light-receiving areas of the two regions 61 and 62 are equal.

[0126] 20, the two cells 5 and 6 have the same shape. However, the shapes of the first cell 5 and the second cell 6 are not limited to being the same.

[0127] In the first boundary line B1, the first end B11 and the second end B12 are positioned opposite each other with the imaginary line IL in between. The first end B11 may be positioned symmetrically to the second end B12 with respect to the imaginary line IL. When the first end B11 is positioned to overlap with the hour character N, the second end B12 may also be positioned to overlap with the hour character N. In the solar panel 4 of FIG. 20, the first end B11 of the first boundary line B1 overlaps with the hour character N9 at nine o'clock, and the second end B12 overlaps with the hour character N3 at three o'clock. The two ends B11, B12 may overlap with the corresponding hour character N while extending in a radial direction centered on the rotation axis 3x.

[0128] The first cell 5 in FIG. 20 has protrusions 51p and 52p. The protrusion 51p is part of the first region 51 and protrudes counterclockwise (CCW) toward the first region 61 of the second cell 6. The protrusion 52p is part of the second region 52 and protrudes clockwise (CW) toward the second region 62 of the second cell 6. The first boundary line B1 has two curved portions B16 and B13 corresponding to the two protrusions 51p and 52p. The curved portion B16 of the first side E1 protrudes toward the second cell 6 while intersecting with the straight line connecting the first end B11 and the rotation axis 3x. The curved portion B13 of the second side E2 protrudes toward the second cell 6 while intersecting with the straight line connecting the second end B12 and the rotation axis 3x.

[0129] The second cell 6 in FIG. 20 has protrusions 61p and 62p. The protrusion 61p is part of the first region 61 and protrudes in the clockwise direction (CW) toward the first region 51 of the first cell 5. The protrusion 62p is part of the second region 62 and protrudes in the counterclockwise direction (CCW) toward the second region 52 of the first cell 5. The first boundary line B1 has two curved portions B14 and B15 corresponding to the two protrusions 61p and 62p. The curved portion B14 of the first side E1 protrudes toward the first cell 5 while intersecting with the straight line connecting the first end B11 and the rotation axis 3x. The curved portion B15 of the second side E2 protrudes toward the first cell 5 while intersecting with the straight line connecting the second end B12 and the rotation axis 3x.

[0130] In the solar panel 4 of Figure 20, when the hand 3 is on the first side E1 of the imaginary line IL, the hand 3 overlaps with two cells 5 and 6 just before and after the nine o'clock position. Also, when the hand 3 is on the second side E2 of the imaginary line IL, the hand 3 overlaps with two cells 5 and 6 just before and after the three o'clock position. Therefore, the solar panel 4 of Figure 20 increases the time period during which the hand 3 overlaps with the two cells 5 and 6, thereby preventing a decrease in the amount of power generation.

[0131] As described above, the wristwatch 1 of this embodiment has a dial 31 and a solar panel 4 arranged on the back side of the dial 31. The solar panel 4 includes multiple solar cells connected in series. The multiple solar cells have an equal light-receiving area S. Each solar cell has a first area 51, 61, 71, 81, 91, 101 arranged on the nine o'clock side of an imaginary line IL connecting twelve o'clock and six o'clock, and a second area 52, 62, 72, 82, 92, 102 arranged on the three o'clock side of the imaginary line IL. In one solar cell, the light-receiving area of ​​the first area is equal to the light-receiving area of ​​the second area.

[0132] The boundary line Bj between two adjacent solar cells has first ends B11, B21, B31, B41, B51, and B61 located on the nine o'clock side of the imaginary line IL, and second ends B12, B22, B32, B42, B52, and B62 located on the three o'clock side of the imaginary line IL. In each boundary line Bj, the first and second ends are positioned facing each other with the imaginary line IL in between. This arrangement of the two ends makes it possible to reduce the total length of the boundary line Bj. Furthermore, since the light-receiving areas of the first and second regions in each solar cell are equal, a decrease in power generation when part of the solar panel 4 is shaded is reduced.

[0133] The first and second ends of one boundary line Bj may be arranged in line-symmetrical positions with respect to the imaginary line IL. This arrangement makes it possible to minimize the total length of the boundary line Bj. Furthermore, the symmetrical arrangement makes it less likely that an imbalance in the light-receiving area will occur due to the influence of the time character N.

[0134] The first end may be positioned so as to equally divide the outer periphery of the dial 31 on the nine o'clock side of the imaginary line IL. The second end may be positioned so as to equally divide the outer periphery of the dial 31 on the three o'clock side of the imaginary line IL. With this positioning, the influence of the dividing portion M and the like is distributed in a balanced manner to each solar cell.

[0135] The wristwatch 1 may have hands 3 and an hour character N arranged on the dial 31. In this case, at least one boundary line Bj may have a first end that extends radially around the rotation axis 3x of the hands 3 and overlaps with the hour character N, or may have a second end that extends radially and overlaps with the hour character N. By overlapping at least one of the first end or second end with the hour character N, it is possible to maximize the amount of power generation in the solar panel 4.

[0136] The wristwatch 1 may have hands 3. In this case, the boundary line Bj may have curved portions B13, B14, B23, B24, B33, B34, B43, B44, B53, and B54, which are curved so that one of two solar cells adjacent to each other across the boundary line Bj has a protrusion that protrudes toward the other solar cell. If this protrusion is located on the nine o'clock side of the imaginary line IL, the curved portion preferably intersects with a line connecting a first end connected to the curved portion and the rotation axis 3x of the hand 3. If the protrusion is located on the three o'clock side of the imaginary line IL, the curved portion preferably intersects with a line connecting a second end connected to the curved portion and the rotation axis 3x of the hand 3. By having the curved portion intersect with a line connecting an end of the boundary line Bj and the rotation axis 3x in this way, the hand 3 is more likely to overlap with multiple solar cells. As a result, a decrease in the amount of power generated by the solar panel 4 is suppressed.

[0137] In the wristwatch 1 of this embodiment, the portion of each boundary line Bj excluding the first and second ends is curved, but the shape of the boundary line Bj is not limited to this. For example, the boundary line Bj may have a portion that extends linearly in addition to the first and second ends.

[0138] In this embodiment, examples of the solar panel 4 including two solar cells to six solar cells have been described. However, the upper limit of the number of solar cells included in the solar panel 4 is not limited to six. The solar panel 4 may also be configured with seven or more solar cells. In this embodiment, "equal areas" of solar cells means that differences in area of, for example, about 5% due to the influence of manufacturing errors are allowed. Also, for example, through holes may be provided on the dividing lines of solar cells to provide small hands on wristwatch 1, and "equal areas" of solar cells means that differences in area of ​​about 5% caused by the influence of the through holes are allowed.

[0139] The contents disclosed in the above embodiments can be implemented in appropriate combinations. [Explanation of symbols]

[0140] 1: Wristwatch 2: outer case, 3: pointer, 3x: rotating axis 4: Solar panel, 4c: Through hole 5: First cell, 6: Second cell, 7: Third cell, 8: Fourth cell 9: Fifth cell, 10: Sixth cell 11: Windshield, 12: Battery 21: Case body, 22: Can 31: Dial, 32: Second hand, 33: Minute hand, 34: Hour hand, 35: First button 36: Second button, 37: Crown 51,61,71,81,91,101:First area 52,62,72,82,92,102:Second area 51p, 61p, 71p, 81p, 91p, 101p: Protrusion 52p, 62p, 72p, 82p, 92p, 102p: Protrusion B1,B2,B3,B4,B5:Border line B11, B21, B31, B41, B51, B61: First end B12, B22, B32, B42, B52, B62: Second end B13, B14, B23, B24, B33, B34, B43, B44, B53, B54: curved section CW: Clockwise, CCW: Counterclockwise E1: First side, E2: Second side IL: Virtual line M: cut N,N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11,N12: Time character R1,R2,R3,R4,R5: Straight line S1,S2,S3,S4,S5,S6: Light receiving area S11, S21, S31, S41, S51, S61: light receiving area of ​​the first region S12, S22, S32, S42, S52, S62: light receiving area of ​​the second region

Claims

1. The dial and a solar panel disposed on the back side of the dial; Equipped with The solar panel includes a plurality of solar cells connected in series; The plurality of solar cells have equal light-receiving areas, Each of the solar cells has a first region disposed on the nine o'clock side of an imaginary line connecting twelve o'clock and six o'clock, and a second region disposed on the three o'clock side of the imaginary line, In one solar cell, the light receiving area of ​​the first region and the light receiving area of ​​the second region are equal, a boundary line between two adjacent solar cells has a first end located on the nine o'clock side of the imaginary line and a second end located on the three o'clock side of the imaginary line, In one of the boundary lines, the first end and the second end are disposed at positions facing each other with the imaginary line therebetween. A wristwatch characterized by

2. At one of the boundary lines, the first end and the second end are arranged at positions symmetrical with respect to the imaginary line.

2. The wristwatch according to claim 1.

3. the first end portion is disposed so as to equally divide the outer periphery of the dial on the nine o'clock side of the imaginary line, The second end portion is disposed so as to equally divide the outer periphery of the dial on the 3 o'clock side of the imaginary line.

2. The wristwatch according to claim 1.

4. Guidelines and hour characters arranged on the dial; Equipped with At least one of the boundary lines has the first end portion that extends in a radial direction around the rotation axis of the hand and overlaps with the hour character, or the second end portion that extends in the radial direction and overlaps with the hour character.

2. The wristwatch according to claim 1.

5. With guidelines, the boundary line has a curved portion that is curved so that one of the two solar cells adjacent to each other across the boundary line has a protruding portion that protrudes toward the other solar cell, When the protruding portion is located on the nine o'clock side of the imaginary line, the curved portion intersects with a straight line connecting the first end portion connected to the curved portion and the rotation axis of the hand, When the protrusion is located on the three o'clock side of the imaginary line, the curved portion intersects with a straight line connecting the second end connected to the curved portion and the rotation axis of the pointer.

2. The wristwatch according to claim 1.

Images