JP7184557B2 - dial, solar-powered watch - Google Patents

Description

The present invention relates to a dial and a solar-powered timepiece.

2. Description of the Related Art A solar-powered timepiece uses a light-transmitting dial to allow light to enter the solar cell. The solar cell has a unique dark purple color, and if the solar cell is seen through the dial, it may spoil the appearance. Therefore, for example, in the dial disclosed in Patent Document 1, unevenness is formed on the lower surface, which is composed of mountain and valley portions whose cross-sectional shape is approximately right-angled, thereby dispersing and diffusing light. It is devised to erase the color tone of the battery.

JP 2011-174948 A

As disclosed in Patent Document 1, when the lower surface of the dial is uneven, the reflectance of light on the dial increases, and the visibility of the internal structure of the watch provided on the lower side of the dial decreases. On the other hand, there is a possibility that the amount of power generated by the solar cell will decrease due to the decrease in light transmittance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a dial for a solar-powered timepiece and a solar-powered timepiece that can secure a power generation amount without impairing the appearance. It is in.

The invention disclosed in the present application for solving the above problems has various aspects, and the outlines of typical aspects are as follows.

(1) A light-transmitting dial for a timepiece with a solar cell, wherein the lower surface of the dial comprises a valley portion recessed toward the upper surface of the dial and the valley portion adjacent to the valley portion. The depth of the valley portion and the height of the mountain portion in the thickness direction of the dial are equal, and the direction intersecting the thickness direction in a cross-sectional view. , wherein the width of the valley portion is larger than the width of the mountain portion.

(2) The dial according to (1), wherein the radius of curvature of the bottom portion of the valley portion is larger than the radius of curvature of the top portion of the mountain portion in a cross-sectional view.

(3) The dial according to (1) or (2), wherein the bottom portion of the valley portion has a rounded shape in a cross-sectional view.

(4) The dial according to (3), wherein the top of the ridge portion is rounded in a cross-sectional view, and the bottom is larger and more rounded than the top.

(5) In any one of (1) to (4), the top surface of the dial is flat, and the maximum inclination angle of the bottom of the valley portion with respect to the top surface in a cross-sectional view is A dial that is smaller than the maximum inclination angle of the top of the dial.

(6) The dial according to any one of (1) to (5), wherein the valley portion and the mountain portion are concentrically or spirally formed on the lower surface.

(7) In any one of (1) to (6), the dial is made of polycarbonate resin or acrylic resin.

(8) A solar battery timepiece including the dial according to any one of (1) to (7) and a solar battery arranged on the lower surface side of the dial.

(9) The solar battery watch according to (8), wherein the unevenness is formed at a position overlapping at least the solar battery in a plan view.

According to aspects (1) to (9) of the present invention, it is possible to provide a dial for a solar-powered timepiece and a solar-powered timepiece that can secure a power generation amount without impairing the appearance. .

1 is a plan view showing an electronic timepiece according to this embodiment; FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; 1 is a cross-sectional view showing an outline of a dial and a solar cell of this embodiment; FIG. It is the top view which looked at the dial|plate of this embodiment from the lower surface side. FIG. 10 is a schematic diagram for explaining a comparison of light transmission through uneven grooves formed on a dial of a conventional example and light transmission through uneven grooves formed on a dial of the present embodiment; FIG. 4 is a schematic diagram illustrating transmission of light in grooves and grooves formed on the dial of the present embodiment. FIG. 4 is a schematic diagram illustrating transmission of light in the uneven mountain stripes formed on the dial of the present embodiment. It is a schematic diagram explaining reflection of light in this embodiment, and transmission. FIG. 4 is a schematic diagram for explaining the details of the shape of the unevenness on the lower surface of the dial according to the embodiment; FIG. 4 is a schematic diagram for explaining the details of the shape of the unevenness on the lower surface of the dial according to the embodiment; FIG. 4 is a schematic diagram for explaining the details of the shape of the unevenness on the lower surface of the dial according to the embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention (hereinafter referred to as the present embodiment) will be described in detail below with reference to the drawings.

FIG. 1 is a plan view showing a solar battery watch according to this embodiment. FIG. 2 is a cross-sectional view taken along line AA of FIG. In FIG. 2, the crown 13, which will be described later, is omitted from the illustration, and in order to make the arrangement of the hands easier to understand, the minute hand 16 is directed toward 9 o'clock, and the hour hand 15 and second hand 17 are directed toward 3 o'clock. It shows a state facing the direction of

FIG. 1 shows a case 10, which is the exterior (watch case) of the solar-powered timepiece 1, a dial 14 arranged inside the case 10, and an hour hand 15, a minute hand 16, and a second hand 17, which are hands indicating the time. there is In addition, hour characters 49 are provided at predetermined positions on the dial 14 . Band fixing portions 11 for fixing the band extend from the sides of the trunk 10 on the 12 o'clock side and the 6 o'clock side. A button 12 and a crown 13 are arranged on the side of the barrel 10 on the 3 o'clock side for the user to perform various operations.

Note that the clock design shown in FIG. 1 is an example. In addition to what is shown here, for example, the barrel 10 may be rectangular instead of round, and the presence/absence, number, and arrangement of buttons 12 and crown 13 are arbitrary. In addition, in this embodiment, three hands, the hour hand 15, the minute hand 16, and the second hand 17, are used. However, the present invention is not limited to this. , radio wave reception status, remaining battery level, pointers for various displays, date display, and the like may be added.

In this specification, the solar-powered timepiece 1 receives a satellite signal from a satellite that transmits a satellite signal including information on date and time, such as a GPS (Global Positioning System) satellite, and 1 shows a satellite radio-controlled wristwatch having the function of correcting the internal time held inside the watch based on information about the time. However, it is not limited to this, and it may be a radio-controlled watch that receives a general standard radio wave and adjusts the internal time, or a watch that does not have such a time-adjusting function.

As shown in FIG. 2 , the solar-powered timepiece 1 has a windshield 32 made of a transparent material such as glass so as to cover the dial 14 , and the windshield 32 is attached to the case 10 . A back cover 36 is attached to the case 10 on the opposite side of the windshield 32 . In this specification, the side on which the windshield 32 of the watch is arranged (the front side of the page in FIG. 1) is called the upper side, and the side on which the back cover 36 is arranged (the back side of the page in FIG. 1) is called the lower side.

A solar cell 30 is arranged on the lower side of the dial 14, and power is generated by the light that passes through the dial 14 and is incident on the solar cell 30 from the upper side. Therefore, the dial 14 is made of a material that transmits light rays to some extent. For example, the dial 14 may be made of polycarbonate resin or acrylic resin. Further, the resin is not limited to those resins, and any transparent resin such as a fluorinated resin or an ethylene resin may be used.

In this embodiment, as indicated by the dashed line in FIG. 1, the solar cell 30 has a substantially circular shape and is fan-shaped from the 10 o'clock direction to the 2 o'clock direction. A patch antenna 20 for receiving satellite signals is arranged in this notched portion (area where the solar cell 30 does not exist) on the lower side of the dial 14 . In this way, by arranging patch antenna 20 so as not to overlap solar cell 30 in plan view, it is possible to suppress the influence of the electrodes included in solar cell 30 on the reception sensitivity of patch antenna 20 . Note that the shape of the solar cell is not limited to one in which the fan-shaped notch is formed. For example, it may be a ring-shaped (doughnut-shaped) solar cell in which the central portion is cut off, or a C-shaped solar cell in which a part of the ring shape is cut off. Furthermore, the outer shape is not limited to a circular one, and a solar cell having a rectangular outer shape may be used.

As shown in FIG. 2 , the solar-powered timepiece 1 further includes a transflective plate 47 provided between the dial 14 and the solar battery 30 and a movement 38 provided below the solar battery 30 . The movement 38 includes a train wheel and a motor for driving hands, a clock circuit including a crystal oscillator for keeping time, a controller for controlling the entire solar-powered clock 1, etc., all assembled together in a frame called a main plate. be. The movement 38 operates by receiving power from a storage battery attached to the movement 38 . The storage battery stores power generated by the solar cell 30 while supplying power to the movement 38, and is, for example, a button-type lithium secondary battery.

In this embodiment, the solar cell 30 is provided integrally with the movement 38 . Further, the movement 38 is provided with a needle shaft projecting from the upper surface of the dial plate 14, and a second hand 17, a minute hand 16 and an hour hand 15 are attached to the tip of the needle shaft. A windshield 32 is fixed to the trunk 10 so as to cover them.

Next, the configuration of the dial 14 of this embodiment will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a cross-sectional view showing an outline of the dial and solar cell of this embodiment. FIG. 4 is a plan view of the dial of the present embodiment as viewed from below.

Between the dial 14 and the solar cell 30, as shown in FIG. 2, a semi-transmissive reflector 47 may be provided in order to properly transmit and reflect incident light. 3, illustration of the semi-transmissive reflector 47 is omitted. Also, in FIG. 3, hatching is omitted to avoid complicating the drawing. Further, as shown in FIG. 3, the space between the lower surface of the dial 14 and the solar cell 30 is an air layer 24 . Since the dial 14 and the air layer 24 have different refractive indices, light is refracted or reflected at the interface between the lower surface of the dial 14 and the air layer 24 .

In this embodiment, the lower surface of the dial 14 is formed with unevenness, which consists of a valley portion 141 recessed upward and a mountain portion 142 protruding downward adjacent to the valley portion 141. . The reason why the unevenness is formed on the lower surface of the dial 14 is that light is reflected at the interface between the lower surface of the dial 14 and the air layer 24, so that the lower surface of the dial 14, such as the solar cell 30, is visible from the outside. This is to make the internal structure provided in the inconspicuous. The height and pitch of the unevenness are preferably several tens of μm to one hundred and several tens of μm.

In this embodiment, the most recessed portion of the lower surface of the dial 14 is called a bottom portion 141a, and the most projected portion is called a top portion 142a. Further, in the present embodiment, the valley portion 141 is a portion above the intermediate portion between the bottom portion 141a and the top portion 142a in the thickness direction of the dial 14, and the mountain portion 142 is a portion in the thickness direction of the dial 14. It is defined as a portion below the middle between the bottom portion 141a and the top portion 142a. That is, in this embodiment, the depth of the valley portion 141 and the height of the mountain portion 142 in the thickness direction of the dial 14 are equal. Details of the definition of the valley portion 141 and the mountain portion 142 will be described later with reference to FIG.

In the present embodiment, as shown in FIG. 3, the unevenness is formed so that the bottom portion 141a of the valley portion 141 in a cross-sectional view is larger and more rounded than the top portion 142a of the mountain portion 142 . In other words, the unevenness is formed so that the radius of curvature of the bottom portion 141a of the valley portion 141 in a cross-sectional view is larger than the radius of curvature of the top portion 142a of the mountain portion 142 .

The unevenness may be formed concentrically as shown in FIG. 4(a) on the lower surface of the dial 14, or may be formed in a spiral shape as shown in FIG. 4(b). 4(a) and 4(b), the solid line indicates the top portion 142a of the ridge portion 142, and the portion between the solid lines indicates the bottom portion 141a of the valley portion 141. As shown in FIG. However, the shape of the unevenness shown in FIGS. 4(a) and 4(b) is an example, and may be formed, for example, in a stripe shape or a radial shape. pattern may be formed. 4(a) and 4(b) show an example in which unevenness is formed in the entire region of the dial 14, but the present invention is not limited to this, and overlaps with the solar cell 30 at least in plan view. It suffices if the region is formed with unevenness. That is, for example, in the area overlapping the area where the patch antenna 20 shown in FIG.

Further, the details of light transmission through the unevenness formed on the dial 14 will be described with reference to FIGS. 5 to 7. FIG. FIG. 5 is a schematic diagram for explaining a comparison of light transmission through the uneven grooves formed on the dial of the conventional example and light transmission through the uneven grooves formed on the dial of the present embodiment. It is a diagram. 6A and 6B are schematic diagrams for explaining the transmission of light in the uneven grooves formed on the dial of the present embodiment. 7A and 7B are schematic diagrams for explaining the transmission of light in the uneven mountain stripes formed on the dial of the present embodiment.

In order to reflect light at the interface between the lower surface of the dial 14 and the air layer 24, it has been conventional to form unevenness on the lower surface of the dial 14. It was a rectangular shape such as a right angle. A dashed line in FIG. 5 indicates the bottom of the valley portion in the conventional example. The dashed arrows in FIG. 5 indicate the optical path of light in the conventional example, and the incident light l1 incident on the interface between the lower surface of the dial 14 and the air layer 24 and the transmitted light (refracted light) at the interface. l2 and reflected light l3. Solid arrows in FIG. 5 indicate optical paths of light in the present embodiment, and include incident light L1 incident on the interface between the lower surface of the dial 14 and the air layer 24, and transmitted light (refracted light) at the interface. L2 is shown.

Here, it is known that the reflectance of light depends on the angle of incidence (Fresnel's equation). Specifically, it is known that the reflectance increases as the incident angle of light incident on the interface increases, and the reflectance decreases as the incident angle decreases. In other words, it is known that the transmittance decreases as the incident angle of light incident on the interface increases, and the transmittance increases as the incident angle decreases. In other words, the transmittance of light (incidence angle of 0 degrees) that is perpendicularly incident on the interface is the highest. Here, the reflectance is the ratio of the reflected light flux to the light flux incident on the interface between substances having different refractive indices. Also, the transmittance is the ratio of the transmitted light flux to the light flux incident on the interface between different substances.

In FIG. 5, in order to simplify the explanation, light incident perpendicularly (at 90 degrees) to the upper surface 145 of the dial 14 is positioned between the lower surface of the dial 14 and the air layer 24 at the bottom 141 a of the valley portion 141 . An example of reflection and transmission at the interface with is shown. In this embodiment, the upper surface 145 of the dial 14 is flat.

Here, in the conventional example, the cross-sectional shape of the bottom portion of the valley portion is square, and a slope inclined at a predetermined angle with respect to the upper surface 145 is formed. The light l1 that is incident perpendicularly to the upper surface 145 of the dial 14 is incident on the slope forming the bottom at a predetermined angle of incidence, and is partially reflected.

On the other hand, in the present embodiment, the cross-sectional shape of the bottom portion 141a of the valley portion 141 is rounded. Therefore, the cross-sectional shape of the bottom portion 141a of the valley portion 141 is less inclined with respect to the top surface 145 of the dial 14 (nearly parallel to the top surface 145) compared to the configuration of the conventional example. Therefore, in this embodiment, the angle of incidence of light incident on the interface between the bottom portion 141a of the valley portion 141 and the air layer 24 is smaller than in the conventional example. Due to such a configuration, in this embodiment, the reflectance of light at the interface between the bottom 141a of the valley portion 141 and the air layer 24 is low and the transmittance is high as compared with the conventional example. Therefore, in the present embodiment, the amount of light reaching the solar cell 30 arranged on the lower side of the dial 14 is greater than in the conventional example, and the amount of power generated by the solar cell 30 is large.

As described above, by making the cross-sectional shape of the bottom portion 141a of the valley portion 141 rounded, the transmittance of light can be improved, and the amount of power generated by the solar cell 30 can be improved. Furthermore, by making the top portion 142a of the ridge portion 142 have a rounded cross-sectional shape, the light transmittance can be improved and the amount of power generated by the solar cell 30 can be increased. However, as described below, the cross-sectional shape of the bottom 142a of the valley portion 141 is rounded rather than the cross-sectional shape of the top portion 142a of the mountain portion 142 is rounded. more power generation can be expected. Therefore, in the present embodiment, the unevenness is formed so that the bottom portion 141a of the valley portion 141 in a cross-sectional view is larger and more rounded than the top portion 142a of the mountain portion 142 .

As shown in FIG. 6, the interface between the bottom portion 141a of the groove portion 141 and the air layer 24 receives light from multiple directions, including light traveling substantially parallel to the upper surface 145 of the dial 14. Light is transmitted through the interface between the valley portion 141 and the air layer 24 .

On the other hand, as shown in FIG. 7, at the apex portion 142a of the ridge portion 142, the light incident on the apex portion 142a at a small angle of inclination (dotted line arrow in FIG. 7) It is not transmitted light that passes through the interface with 24 . This is because the light indicated by the dotted arrow in FIG. 7 is incident on the dial 14 from the outside of the dial 14 . As described above, the light indicated by the dotted arrow in FIG. 7 does not participate in the transmitted light at the interface, so that the cross-sectional shape of the top portion 142a is rounded to improve the transmittance. can be said to be less effective than improving the transmittance by making the shape rounded.

Therefore, in the present embodiment, the cross-sectional shape of the bottom portion 141a of the valley portion 141, which is expected to further improve the transmittance, is made into a large rounded shape. In the present embodiment, the cross-sectional shape of the apex 142a of the ridge portion 142 is also rounded, but the cross-sectional shape of the apex 142a is not limited to this. It may be rectangular such as a right angle. Also, the bottom portion 141 a of the valley portion 141 does not necessarily have to have a rounded shape, as long as it has a surface with a small inclination with respect to the upper surface 145 . That is, the bottom portion 141a may include a plane parallel to the top surface 145, for example.

Furthermore, the visibility of the solar cell 30 will be described with reference to FIGS. 8 to 10. FIG. As described above, the higher the transmittance of the dial 14, the more light is incident on the solar cell 30, and the greater the amount of power generated. On the other hand, the user visually recognizes the solar cell 30 through the dial 14 according to the transmittance of the light reflected by the surface of the solar cell 30 through the dial 14 . Here, since the solar cell 30 has a unique dark purple color, it is preferable from an aesthetic point of view that it is not conspicuous from the outside. Moreover, the solar cell 30 has a partially notched shape as shown in FIG. Some solar cells 30 are divided into cells, and when such a solar cell 30 is used, it is not aesthetically pleasing if the dividing lines between the cells are seen through the dial 14 . That is, it can be said that a configuration in which reflected light from the solar cell 30 is less likely to pass through the dial 14 is more aesthetically pleasing.

FIG. 8 is a schematic diagram for explaining reflection and transmission of light in this embodiment. In FIG. 8, the transmitted light L11 transmitted through the bottom portion 141a of the valley portion 141, the transmitted light L12 transmitted through the top portion 142a of the mountain portion 142, and the transmitted light incident on the solar cell 30 are reflected by the solar cell 30. reflected light L13, transmitted light L14 transmitted through the bottom portion 141a of the valley portion 141 of the reflected light L13, and transmitted light L15 transmitted through the top portion 142a of the mountain portion 142 of the reflected light L13. In addition, the length of the arrow in FIG. 8 schematically represents the relative amount of light.

Transmitted light L11 and transmitted light L12 enter solar cell 30 . As a result, power is generated in the solar cell 30, and part of the light is reflected toward the dial 14 as reflected light L13. The user visually recognizes the solar cell 30 by the reflected light L13.

Here, the transmittance of the reflected light L13 increases as the incident angle with respect to the interface between the lower surface of the dial 14 and the air layer 24 decreases. Reflected light L13 is incident on the apex 142a of the ridge portion 142 from the most directions. Regarding this point, in the present embodiment, the cross-sectional shape of the top portion 142a of the ridge portion 142 is less rounded than the cross-sectional shape of the bottom portion 141a of the valley portion 141 . Therefore, in the present embodiment, the transmittance of the reflected light L13 to the dial 14 is not so high, and the solar cell 30 is difficult to see from the outside and is inconspicuous.

As described above, according to the configuration of the solar cell-equipped timepiece 1 of the present embodiment, the transmittance of light incident from the upper surface 145 side of the dial 14 is high, and the amount of power generated by the solar cell 30 is improved. Further, according to the structure of the solar cell timepiece 1 of the present embodiment, the interface between the lower surface of the dial 14 and the air layer 24 in the light reflected by the solar cell 30 and directed from the lower surface of the dial 14 to the upper surface 145 side. , the transmittance is not so high, and the solar cell 30 is hardly noticeable from the outside.

Further, details of the uneven shape of the lower surface of the dial 14 of the present embodiment will be described with reference to FIGS. 9 to 11. FIG. 9 to 11 are schematic diagrams for explaining the details of the uneven shape of the lower surface of the dial of this embodiment.

As described above, in the unevenness of the conventional example, the cross-sectional shape of the bottom portion of the valley portion and the top portion of the mountain portion is rectangular, and the valley portion and the mountain portion have substantially the same outer shape. In this embodiment, it is preferable to adopt a shape in which the square shape of the conventional example is rounded. In this embodiment, the bottom portion 141a of the valley portion 141 is larger than the top portion 142a of the mountain portion 142 and has a rounded shape. The solid line in FIG. 9 indicates the valley portion 141 and the mountain portion 142 of this embodiment, and the broken line indicates the bottom portion of the valley portion and the top portion of the mountain portion in the conventional example.

Further, as described above, the depth of the valley portion 141 and the height of the mountain portion 142 in the thickness direction of the dial 14 are defined to be equal. In the conventional example, as shown in FIG. 9, the upper portion is defined as the valley portion and the lower portion is defined as the mountain portion with respect to the midpoint C1 between the bottom portion and the top portion. On the other hand, in the present embodiment, the valley portion 141 is defined above the middle C2 between the bottom portion 141a and the top portion 142a, and the mountain portion 142 is defined below. The midpoint C2 is located below the midpoint C1 because the roundness of the valley portion 141 is large. Therefore, as shown in FIG. 9, in this embodiment, the width W1 of the valley portion 141 in the direction perpendicular to (crossing) the thickness direction of the dial 14 is larger than the width W2 of the mountain portion 142. .

10, the relationship between the bottom portion 141a of the ridge portion 141 and the top portion 142a of the ridge portion 142 in this embodiment will be described from a different point of view. It can be said that the maximum inclination angle θ1 of the bottom portion 141 a of the portion 141 is smaller than the maximum inclination angle θ2 of the top portion 142 a of the ridge portion 142 with respect to the upper surface 145 . Here, the bottom portion 141a indicates a region from the most recessed portion to a predetermined length x1, and the top portion 142a indicates a region from the most projecting portion to a predetermined length x2. be of equal length.

Further, the relationship between the bottom portion 141a of the ridge portion 141 and the top portion 142a of the ridge portion 142 in the present embodiment will be described from another point of view. It can be said that the curvature radius R1 of the bottom portion 141a is larger than the curvature radius R2 of the top portion 142a of the ridge portion 142 . According to the knowledge of the inventors of the present application, the larger the radius of curvature, the higher the light transmittance. Particularly, by increasing the radius of curvature of the bottom portion 141a, the transmittance can be further improved.

Although the embodiment according to the present invention has been described above, the specific configuration shown in this embodiment is shown as an example, and it is not intended to limit the technical scope of the present invention to this. Those skilled in the art may modify these disclosed embodiments as appropriate, and it should be understood that the technical scope of the invention disclosed herein includes such modifications.

1 solar battery watch, 10 case, 11 band fixing part, 12 button, 13 crown, 14 dial, 141 root part, 141a bottom part, 142 mountain part, 142a top part, 145 upper surface, 15 hour hand, 16 minute hand, 17 Second hand, 20 patch antenna, 30 solar cell, 32 windshield, 36 back cover, 38 movement, 47 transflective plate, 49 hour letter.

Claims (9)

A light-transmissive dial for a solar-powered timepiece , comprising a single plate having an upper surface and a lower surface ,
the lower surface includes unevenness formed by a valley portion recessed toward the upper surface side and a mountain portion protruding toward the lower surface side adjacent to the valley portion;
the depth of the ridge portion and the height of the ridge portion in the thickness direction of the dial are equal,
In a cross-sectional view, the width of the valley portion in a direction intersecting the thickness direction is larger than the width of the mountain portion,
The unevenness is formed directly on the lower surface and is exposed to an air layer below the dial.
dial. The lower surface includes a bottom portion that is a part of the valley portion and is the most depressed portion, and a top portion that is a portion of the mountain portion and is the most protruding portion,
The bottom portion is positioned above a central position between the valley portion and the mountain portion in the thickness direction of the dial,
The top portion is positioned below a center position between the valley portion and the mountain portion in the thickness direction of the dial,
the depth of the bottom portion and the height of the top portion in the thickness direction of the dial are equal,
In a cross-sectional view, the radius of curvature of the bottom of the valley portion is larger than the radius of curvature of the top of the mountain portion.
The dial according to claim 1. In a cross-sectional view, the shape of the bottom of the valley portion is rounded.
The dial according to claim 2 . In a cross-sectional view, the shape of the apex of the ridge portion is a rounded shape,
the bottom is larger and more rounded than the top;
The dial according to claim 3. The upper surface of the dial is flat,
The maximum inclination angle of the bottom with respect to the top surface in a cross-sectional view is smaller than the maximum inclination angle of the top with respect to the top surface,
The dial according to any one of claims 2-4 . The valley section and the mountain section are formed concentrically or spirally on the lower surface,
The dial according to any one of claims 1-5. Made of polycarbonate resin or acrylic resin,
The dial according to any one of claims 1-6. A dial according to any one of claims 1 to 7;
a solar cell arranged on the lower surface side of the dial;
including,
A clock with a solar battery. The unevenness is formed at a position overlapping at least the solar cell in plan view,
The solar-powered timepiece according to claim 8.

Images