Clocks

Abstract

Clock. Suppresses distortion of the image seen through a windproof glass. It comprises: a dial (3); a windproof glass (30) protecting the dial (3) and having multiple curved surfaces (FS1, FS2, FS3) with different curvatures (FCn); and hands (11) disposed between the dial and the windproof glass, the windproof glass having: a first curved surface (FS1) having a first curvature (FC1) and containing the center of the windproof glass; and a second curved surface (FS2) adjacent to the first curved surface (FS1) and having a curvature greater than the first curvature (FC1). 2. Curvature (FC2); 3rd surface (FS3), adjacent to 2nd surface (FS2), having a 3rd curvature (FC3) larger than 2nd curvature (FC2), the thickness of the normal direction of the 1st surface is the same as the thickness of the normal direction of the 2nd surface, and in a top view from the dial (3) toward the windshield in the +Z direction, the end (11a) of the pointer is positioned closer to the center (C) of the windshield than the boundary (K23) between the 2nd and 3rd surfaces.

Description

Technical Field

[0001] This invention relates to clocks and watches. Background Technology

[0002] Conventionally, watch cover glass (windproof glass) with curved ends (curved surfaces) is known (e.g., Patent Document 1). For example, when the windproof glass is composed of multiple straight inclined planes, and the windproof glass has ridges at the intersections of these inclined planes, sometimes the dial or hands appear to be cut off by the ridges when viewed through the windproof glass. Patent Document 1 describes a windproof glass with curved ends that does not have ridges; therefore, this defective appearance of the dial and hands being cut off can be eliminated.

[0003] Patent Document 1: Japanese Utility Model Application Publication No. 1-78989

[0004] However, in the windproof glass described in Patent Document 1, there is a situation where the dial and hands appear distorted when viewed through the windproof glass. Summary of the Invention

[0005] Problem-solving methods

[0006] The clock of the present invention comprises: a dial; a windproof glass that protects the dial and has a plurality of curved surfaces with different curvatures; and a hand disposed between the dial and the windproof glass to indicate information other than hours and minutes, the windproof glass having: a first curved surface having a first curvature and including the center of the windproof glass; a second curved surface adjacent to the first curved surface having a second curvature greater than the first curvature; and a third curved surface adjacent to the second curved surface having a third curvature greater than the second curvature, the thickness of the first curved surface in the normal direction being the same as the thickness of the second curved surface in the normal direction, and in a top view from the dial toward the windproof glass in a first direction, the tip of the hand is disposed at a position closer to the center side of the windproof glass than the boundary between the second and third curved surfaces. Attached Figure Description

[0007] Figure 1 This is a top view of the clock as described in the implementation method.

[0008] Figure 2 This is a cross-sectional view of the clock according to the implementation method.

[0009] Figure 3 This is a cross-sectional view of the windshield.

[0010] Figure 4 This is a list showing the radius of curvature, curvature, and thickness of the main parts of the windshield.

[0011] Figure 5It is a photograph showing the state of the grid-like test pattern as seen through the windshield.

[0012] Label Explanation

[0013] 1. Clock; 2. Movement; 3. Dial; 4. Axis; 5. Case; 6. Crown; 8. Hole; 9. Case back; 11. Hands; 11a. End of hand; 12. Hour hand; 12a. End of hour hand; 13. Minute hand; 13a. End of minute hand; 14. Second hand; 14a. End of second hand; 16. Scale; 16a. Outer end of scale; 17. Hour scale; 17a. Outer end of hour scale; 18. Minute scale; 18a. Outer end of minute scale; 30. Window glass. Detailed Implementation

[0014] 1. Implementation Method

[0015] The clock 1 of this embodiment has a movement 2, which is a mechanical body including a drive section. The movement 2, on which the dial 3 and hands 11 are mounted, is housed in a case 5 and protected by a glass barrier 30. Therefore, in the clock 1 of this embodiment, the movement 2, the dial 3, and the glass barrier 30 are arranged sequentially in one direction. Figure 2 Reference).

[0016] In the following description, the direction in which the movement 2, dial 3, and windshield 30 are arranged sequentially is referred to as the +Z direction, and the direction opposite to the +Z direction is referred to as the -Z direction. Furthermore, the direction orthogonal to the +Z direction and extending from the center C of the windshield 30 toward the outer edge E of the windshield 30 is referred to as the X direction.

[0017] Furthermore, the +Z direction is an example of the first direction from the dial toward the windshield in this application. In addition, viewing from the +Z direction side refers to looking down from the first direction from the dial toward the windshield in this application, hereinafter referred to as the top view from the Z direction.

[0018] Additionally, the view taken from the X direction is called the top view from the X direction.

[0019] 1.1 Overview of Clocks

[0020] Figure 1 This is a top view of the clock 1 in this embodiment, illustrating the state of the clock 1 as viewed from the Z direction. Figure 2 yes Figure 1 The cross-sectional view along line AA in this embodiment is a cross-sectional view of clock 1. Figure 1 In the diagram, the center C of the windshield 30 is indicated by a black dot. Figure 2 And then Figure 3 In the diagram, the center of the windshield 30 is indicated by a single-dot dashed line.

[0021] First, refer to Figure 1 and Figure 2 This section describes the outline of clock 1 in this embodiment.

[0022] like Figure 1 As shown, the clock 1 in this embodiment is a three-hand analog watch with a case 5, a dial 3, hands 11, a crown 6, and a windproof glass 30.

[0023] The case 5 is made of a hard metal such as stainless steel or titanium, and houses the movement 2 and the dial 3. The hands 11 include an hour hand 12 to indicate the hour, a minute hand 13 to indicate the minute, and a second hand 14 to indicate the second. Furthermore, the hands lengthen in the order of hour 12, minute 13, and second 14. The crown 6 is the time adjustment knob; pulling it out allows for time correction.

[0024] In addition, the second hand 14 is an example of a pointer in this application that indicates information other than hours and minutes.

[0025] The dial 3 has a scale 16. The scale 16 consists of hour markers 17 and minute markers 18, and is indicated by the hand 11. The hour markers 17 are positioned at the point where one 360-degree circle is divided into 12 parts. The minute markers 18 are positioned at the point where the area between the hour markers 17 and the adjacent hour markers 17 is divided into 5 equal parts. In addition, the hour markers 17 are longer than the minute markers 18.

[0026] In addition, scale 16 (hour scale 17, minute scale 18) is an example of a pointer-indicated scale in this application.

[0027] The windshield 30 is a circular component when viewed from above in the Z direction, protecting the dial 3. Details of the windshield 30 will be described later.

[0028] The X-axis end of the hour hand 12 is the end 12a of the hour hand 12, the X-axis end of the minute hand 13 is the end 13a of the minute hand 13, and the X-axis end of the second hand 14 is the end 14a of the second hand 14. These will be collectively referred to below as the end 11a of the hand 11. Additionally, the X-axis end of the hour scale 17 is the outer end 17a of the hour scale 17, and the X-axis end of the minute scale 18 is the outer end 18a of the minute scale 18. These will be collectively referred to below as the outer end 16a of the scale 16.

[0029] Furthermore, the end 11a of the pointer 11 (the end 12a of the hour hand 12, the end 13a of the minute hand 13, and the end 14a of the second hand 14) is an example of the end of the pointer in this application. The outer end 16a of the scale 16 (the outer end 17a of the hour scale 17 and the outer end 18a of the minute scale 18) is an example of the outer end of the scale in this application.

[0030] like Figure 2As shown, in the clock 1 of this embodiment, a windproof glass 30 is installed on the +Z direction side of the housing 5, and a back cover 9 is installed on the -Z direction side of the housing 5. Between the back cover 9 and the windproof glass 30, a movement 2, a dial 3, and hands 11 are arranged sequentially along the +Z direction.

[0031] That is, the clock 1 of this embodiment has a dial 3, a windproof glass 30 that protects the dial 3, and a pointer 11 disposed between the dial 3 and the windproof glass 30.

[0032] The movement 2 has a shaft 4 for mounting the pointer 11 and a drive mechanism for rotating the shaft 4 (not shown).

[0033] The dial 3 has a hole 8 through which the shaft 4 passes. The shaft 4 extends in the +Z direction relative to the dial 3 through the hole 8. The hands 11 (hour hand 12, minute hand 13, second hand 14) are installed on the part of the shaft 4 that extends in the +Z direction.

[0034] 1.2 Overview of Windproof Glass

[0035] Figure 3 It's a 30mm windshield. Figure 1 The AA-line sectional view in the figure is a sectional view of the windshield 30. Figure 4 This is a list showing the radius of curvature, curvature, and thickness of the main parts of the windshield 30. Figure 5 It is a photograph showing the state of the grid-like test pattern as seen through the windshields 30 and 30A.

[0036] In the following description, the surface of the windshield 30 in the +Z direction is referred to as surface 30a, and the surface of the windshield 30 in the -Z direction is referred to as back surface 30b.

[0037] Next, refer to Figures 1-5 This section provides an overview of the windshield 30.

[0038] The windproof glass 30 is made of sapphire glass. It is manufactured by polishing synthetic sapphire crystals. The windproof glass 30, made of sapphire glass, has the advantages of excellent light transmission and visibility, high hardness, and resistance to damage.

[0039] like Figure 3 and Figure 4As shown, the surface 30a of the windshield 30 has a first surface-side curved surface FS1 including the center C of the windshield 30, a second surface-side curved surface FS2 adjacent to the first surface-side curved surface FS1, and a third surface-side curved surface FS3 adjacent to the second surface-side curved surface FS2. The back surface 30b of the windshield 30 has a first back-side curved surface BS1 including the center C of the windshield 30, a second back-side curved surface BS2 adjacent to the first back-side curved surface BS1, and a third back-side curved surface BS3 adjacent to the second back-side curved surface BS2.

[0040] In addition, the first surface-side curved surface FS1 is an example of the first curved surface in the present application, the second surface-side curved surface FS2 is an example of the second curved surface in the present application, and the third surface-side curved surface FS3 is an example of the third curved surface in the present application.

[0041] In the surface 30a of the windshield 30, the radius of curvature of the first surface-side curved surface FS1 is FR1, the radius of curvature of the second surface-side curved surface FS2 is FR2, and the radius of curvature of the third surface-side curved surface FS3 is FR3. For example, the radius of curvature FR1 is 100 mm, the radius of curvature FR2 is 30 mm, and the radius of curvature FR3 is 5 mm. In the present embodiment, the relationship FR1 > FR2 > FR3 is satisfied.

[0042] In the surface 30a of the windshield 30, the curvature of the first surface-side curved surface FS1 is FC1, the curvature of the second surface-side curved surface FS2 is FC2, and the curvature of the third surface-side curved surface FS3 is FC3. In addition, the curvature is the reciprocal of the radius of curvature. If the radius of curvature increases, the curvature decreases, and if the radius of curvature decreases, the curvature increases. In the present embodiment, the relationship FC1 < FC2 < FC3 is satisfied.

[0043] In addition, the curvature FC1 is an example of the first curvature in the present application, the curvature FC2 is an example of the second curvature in the present application, and the curvature FC3 is an example of the third curvature in the present application.

[0044] In addition, in the following description, the first surface-side curved surface FS1 will be referred to as the first curved surface FS1, the second surface-side curved surface FS2 will be referred to as the second curved surface FS2, and the third surface-side curved surface FS3 will be referred to as the third curved surface FS3.

[0045] On the back surface 30b of the windshield 30, the radius of curvature of the first back-side curved surface BS1 is BR1, the radius of curvature of the second back-side curved surface BS2 is BR2, and the radius of curvature of the third back-side curved surface BS3 is BR3, satisfying BR1 > BR2 > BR3. The curvature of the first back-side curved surface BS1 is BC1, the curvature of the second back-side curved surface BS2 is BC2, and the curvature of the third back-side curved surface BS3 is BC3, satisfying the relationship BC1 < BC2 < BC3.

[0046] Thus, the windshield 30 has multiple curved surfaces with different curvatures (first curved surface FS1, second curved surface FS2, and third curved surface FS3). Moreover, the windshield 30 has: a first curved surface FS1 (first curved surface) having a curvature FC1 (first curvature) and including the center C of the windshield 30; a second curved surface FS2 (second curved surface) adjacent to the first curved surface FS1 and having a curvature FC2 (second curvature) larger than the curvature FC1; and a third curved surface FS3 (third curved surface) adjacent to the second curved surface FS2 and having a curvature FC3 (third curvature) larger than the curvature FC2.

[0047] That is, in the windshield 30, a second surface FS2 with a moderate curvature FCn is provided between the first curved surface FS1 with a smaller curvature FCn located on the center C side and the third curved surface FS3 with a larger curvature FCn located on the outer edge E side. According to this structure, the change in curvature FCn in the direction (X direction) from the center C of the windshield 30 toward the outer edge E is reduced, and the change in curvature FCn in the X direction becomes smooth.

[0048] Furthermore, in the windshield 30, the thickness in the normal direction of the first curved surface FS1 is FT1, the thickness in the normal direction of the second curved surface FS2 is FT2, and the thickness in the normal direction of the third curved surface FS3 is FT3. For example, the thickness FT1 in the normal direction of the first curved surface FS1 is 1 mm.

[0049] In this embodiment, the thickness FT1 in the normal direction of the first surface FS1, the thickness FT2 in the normal direction of the second surface FS2, and the thickness FT3 in the normal direction of the third surface FS3 are the same. That is, the relationship FT1 = FT2 = FT3 is satisfied.

[0050] Thus, this embodiment has a structure in which the thickness FT1 (thickness in the normal direction of the first curved surface FS1) of the windproof glass 30 is the same as the thickness FT2 (thickness in the normal direction of the second curved surface FS2) of the windproof glass 30.

[0051] In this application, "the thickness in the normal direction is the same" means that the deviation of the thickness in the normal direction is less than ±10%. For example, if the thickness FT1 in the normal direction of the first surface FS1 is in the range of 0.9 mm to 1.1 mm and the thickness FT2 in the normal direction of the second surface FS2 is in the range of 0.9 mm to 1.1 mm, then the thickness FT1 in the normal direction of the first surface FS1 and the thickness FT2 in the normal direction of the second surface FS2 are the same, and this is included in the technical scope of this application.

[0052] Generally, when the thickness of the windshield 30 is the same in the normal direction and the curvature FCn is small, the refraction of light through the windshield 30 decreases, and the distortion of the image seen through the windshield 30 decreases. The so-called lens effect weakens, and the image seen through the windshield 30 is less prone to distortion.

[0053] Details will be discussed later. The curvature FC1 of the first surface FS1 and the curvature FCn of the second surface FS2 are relatively small, resulting in less distortion of the images seen through the windshield 30 on the first surface FS1 and the second surface FS2. Figure 5 Reference).

[0054] As a result, in the windshield 30, the first curved surface FS1 and the second curved surface FS2 become viewing surfaces VS that are less prone to image distortion. The user can see the pointer 11 and the scale 16 through the first curved surface FS1 and the second curved surface FS2 of the windshield 30 in a natural state with less image distortion.

[0055] On the other hand, with the same thickness in the normal direction and a large curvature FCn, the refraction of light through the windshield 30 increases, causing the image seen through the windshield 30 to be magnified or reduced, and increasing the distortion of the image. The so-called lens effect becomes stronger, resulting in distortion of the image seen through the windshield 30.

[0056] Details will be discussed later. The curvature FCn of the third surface FS3 is relatively large, resulting in greater distortion of the image seen through the windshield 30 via the third surface FS3 (see reference). Figure 5 ).

[0057] That is, the lens effect becomes extremely large on the third curved surface FS3, and the distortion of the image seen through the third curved surface FS3 becomes greater. Therefore, it is not desirable to use the third curved surface FS3 of the windshield 30 as the observation surface VS, which is not prone to image distortion.

[0058] In the windshield 30, the boundary between the first curved surface FS1 and the second curved surface FS2 is boundary K12, and the boundary between the second curved surface FS2 and the third curved surface FS3 is boundary K23. Figure 3 In the diagram, boundaries K12 and K23 are indicated by black circles. Additionally, in... Figure 1 as well as Figure 2 In the diagram, boundary K12 is shown with a dashed line, and boundary K23 is shown with a double-dotted line.

[0059] In addition, boundary K12 is an example of the boundary between the first surface and the second surface in this application, and boundary K23 is an example of the boundary between the second surface and the third surface in this application.

[0060] like Figure 1 and Figure 2 As shown, in a top view from the Z direction, the outer end 16a of the scale 16 (the outer end 17a of the hour scale 17 and the outer end 18a of the minute scale 18) is positioned between the boundary K23 of the second surface FS2 and the third surface FS3 and the end 11a of the hand 11. More specifically, in a top view from the Z direction, the outer end 16a of the scale 16 (the outer end 17a of the hour scale 17 and the outer end 18a of the minute scale 18) is positioned between the boundary K23 of the second surface FS2 and the third surface FS3 and the end 14a of the second hand 14.

[0061] Furthermore, in a top view from the Z direction, the scale 18 is configured to overlap with the second surface FS2, and the scale 17 is configured to overlap with both the first surface FS1 and the second surface FS2.

[0062] Therefore, the user can see scale 16 through the first curved surface FS1 and the second curved surface FS2 of the windshield 30, and can see scale 16 with less image distortion. As a result, the visibility of scale 16 is improved.

[0063] In a top view from the Z direction, the ends 11a of the pointer 11 (the ends 12a of the hour hand 12, the ends 13a of the minute hand 13, and the ends 14a of the second hand 14) are positioned closer to the center C side of the windshield 30 than the boundary K23 between the second surface FS2 and the third surface FS3.

[0064] In detail, in a top view from the Z direction, the end 12a of the hour hand 12 is positioned on the side of the center C of the windshield 30, closer to the boundary K12. The end 13a of the minute hand 13 and the end 14a of the second hand 14 are positioned between the boundary K12 and the boundary K23.

[0065] Therefore, the user can see the pointer 11 through the first curved surface FS1 and the second curved surface FS2 of the windshield 30, and can see the pointer 11 with less image distortion. As a result, the visibility of the pointer 11 is improved.

[0066] Furthermore, in this embodiment, the area of ​​the first curved surface FS1 in the windshield 30 is the largest when viewed from above in the Z direction.

[0067] Generally, when the thickness in the normal direction is the same, the lens effect depends on the curvature FCn. When the curvature FCn decreases, the lens effect weakens; when the curvature FCn increases, the lens effect strengthens. In the windshield 30 of this embodiment, the curvature FC1 of the first curved surface FS1 is the smallest, therefore, the lens effect is the weakest, and the distortion of the image seen through the first curved surface FS1 is minimal. Therefore, when the area of ​​the first curved surface FS1 is the largest, the portion with the least distortion in the observation surface VS of the windshield 30 is the largest, making it easiest to see time displays, etc. Therefore, the structure with the largest area of ​​the first curved surface FS1 is preferred.

[0068] Furthermore, in this embodiment, in a top view taken from the Z direction, scale 16 does not overlap with the third surface FS3.

[0069] In the third curved surface FS3, the lens effect becomes extremely large, and the distortion of the image seen through the third curved surface FS3 of the windshield 30 becomes greater. Therefore, it is not desirable to use the third curved surface FS3 of the windshield 30 as the observation surface VS, which is less likely to produce image distortion.

[0070] If scale 16 does not overlap with the third curved surface FS3 in a top view from the Z direction, the user will not see scale 16 in a distorted state through the third curved surface FS3 of the windshield 30, thus improving the visibility of scale 16.

[0071] In this embodiment, a second surface FS2 with a moderate curvature FCn is disposed between a first surface FS1 with a small curvature FCn and a third surface FS3 with a large curvature FCn. The second surface FS2 is disposed between the first surface FS1 and the third surface FS3 to reduce the change in curvature FCn in the direction (X direction) from the center C of the windshield 30 toward the outer edge E, so that the change in curvature FCn is smooth.

[0072] For example, the point where the curvature FCn changes becomes the point where optical properties such as light refraction change. The smoother the change, the less noticeable the distortion of the image. In this embodiment, by utilizing the second surface FS2, the change in curvature FCn becomes smaller, and the change in optical properties caused by the change in curvature FCn becomes smaller. As a result, the user can see the pointer 11 and the scale 16 through the first surface FS1 and the second surface FS2 of the windproof glass 30 in a natural state with less image distortion.

[0073] Furthermore, in this embodiment, in addition to the first surface FS1 with a smaller curvature FCn, the second surface FS2 with a moderate curvature FCn can also be effectively used as the observation surface VS with less image distortion. Therefore, compared with the case where the second surface FS2 is not provided, the area of ​​the beneficial region in the windshield 30 that can be used as the observation surface VS becomes larger.

[0074] Figure 5 The photograph shows the following: the windproof glass 30 of this embodiment and the windproof glass 30A of the comparative example are placed on test paper printed with a grid-shaped test pattern, showing what kind of grid-shaped test pattern can be seen through the windproof glass 30 and 30A.

[0075] exist Figure 5 In this embodiment, the windshield 30 is represented by the symbol F, and the windshield 30A of the comparative example is represented by the symbol G.

[0076] exist Figure 5 In this embodiment, the symbol F represents the windshield 30. The windshield 30 of this embodiment has a first curved surface FS1 with a small curvature FCn disposed on the center C side, a second curved surface FS2 with a moderate curvature FCn disposed on the outer edge E side, and a third curved surface FS3 with a large curvature FCn disposed on the outer edge E side. The second curved surface FS2 with a moderate curvature FCn is disposed between the first curved surface FS1 with a small curvature FCn and the third curved surface FS3 with a large curvature FCn.

[0077] On the other hand, Figure 5 In the figure, G is the windshield 30A of the comparative example. The windshield 30A of the comparative example has a first curved surface FS1A with a small curvature FCn disposed on the center C side, a third curved surface FS3A with a large curvature FCn disposed on the outer edge E side, and does not have a second curved surface FS2 with a moderate curvature FCn.

[0078] This is the main difference between the windshield 30 of this embodiment and the windshield 30A of the comparative example. That is, the windshield 30A of the comparative example is characterized by a drastic change in curvature FCn in the direction from the center C of the windshield 30 toward the outer edge E, and the area of ​​the third curved surface FS3A with a large curvature FCn is larger than that of the windshield 30 of this embodiment.

[0079] Furthermore, the curvature FCn (curvature FC1) of the first surface FS1 is approximately the same as the curvature FCn of the first surface FS1A, and the curvature FCn (curvature FC3) of the third surface FS3 is approximately the same as the curvature FCn of the third surface FS3A.

[0080] As mentioned above, when the thickness in the normal direction is the same, the effect of the lensing effect depends on the curvature FCn, and satisfies the following relationship: when the curvature FCn decreases, the effect of the lensing effect weakens, and when the curvature FCn increases, the effect of the lensing effect strengthens.

[0081] like Figure 5As shown in the area J enclosed by the dashed line, in the windshield 30 of this embodiment, when the grid-like test pattern is viewed through the first curved surface FS1 with a small curvature FCn and the second curved surface FS2 with a moderate curvature FCn, no image distortion occurs. However, when the grid-like test pattern is viewed through the third curved surface FS3 with a large curvature FCn, image distortion occurs.

[0082] like Figure 5 As shown in the area K enclosed by the dashed line, in the windshield 30A of the comparative example, no image distortion occurs when the grid-like test pattern is viewed through the first curved surface FS1A with a smaller curvature FCn, but image distortion occurs when the grid-like test pattern is viewed through the third curved surface FS3A with a larger curvature FCn.

[0083] In the windshield 30 of this embodiment, the curvature FC1 of the first curved surface FS1 is the smallest. Therefore, the effect of the lens effect is the weakest, and the distortion of the image seen through the first curved surface FS1 is the smallest.

[0084] The curvature FC2 of the second surface FS2 is greater than the curvature FC1 of the first surface FS1. Therefore, the distortion of the image seen through the second surface FS2 is greater than that seen through the first surface FS1. However, the curvature FC2 of the second surface FS2 is greater than the curvature FC1 of the first surface FS1 and smaller than the curvature FC3 of the third surface FS3. Therefore, the change in curvature Fn can be suppressed to a relatively stable value. In addition, the thickness in the normal direction is the same in the first surface FS1 and the second surface FS2. Therefore, the change in optical properties is smaller, and the distortion of the image seen through the second surface FS2 of the windproof glass 30 becomes extremely slight. In addition to the first surface FS1 of the windproof glass 30, the second surface FS2 of the windproof glass 30 can also be used as an observation surface VS that is less prone to image distortion.

[0085] As a result, when a user sees the pointer 11 and the scale 16 through the first curved surface FS1 and the second curved surface FS2 of the windshield 30, the pointer 11 and the scale 16 can be seen in a natural state with less image distortion.

[0086] On the other hand, the lens effect of the third curved surface FS3 is extremely large, and the distortion of the image seen through the third curved surface FS3 is increased. Therefore, it is not desirable to use the third curved surface FS3 of the windshield 30 as the observation surface VS, which is not prone to image distortion.

[0087] On the other hand, in the windshield 30A of the comparative example, when the grid-like test pattern is seen through the first curved surface FS1A with a smaller curvature FCn of the windshield 30A, image distortion is not easily generated. Therefore, the first curved surface FS1A of the windshield 30A can be used as the observation surface VS that is not prone to image distortion.

[0088] However, in the third curved surface FS3A of the windshield 30A with a large curvature FCn, the lens effect becomes greater, and the distortion of the image seen through the third curved surface FS3A becomes greater. In addition, the area of ​​the third curved surface FS3A in the comparative example is larger than that in this embodiment, reaching the position where it overlaps with the scale 16 or the pointer 11. Therefore, the image of the scale 16 or the pointer 11 is distorted, and it is not easy to obtain the desired appearance.

[0089] Furthermore, in the comparative example windshield 30A, there is no second surface FS2 with a moderate curvature FCn between the first curved surface FS1A with a small curvature FCn and the third curved surface FS3A with a large curvature FCn. Therefore, compared with the windshield 30 of this embodiment, the area that can be used as the observation surface VS in the windshield 30A is smaller.

[0090] Furthermore, a sharp change in curvature FCn occurs at the boundary between the first surface FS1A with small curvature FCn and the third surface FS3A with large curvature FCn. Consequently, significant image distortion may occur in the region where the curvature FCn changes abruptly. That is, the point of change in curvature FCn becomes a point of change in optical properties such as light refraction, and the change becomes rapid, resulting in noticeable image distortion.

[0091] In the windshield 30 of this embodiment, a second surface FS2 with a moderate curvature FCn is disposed between a first surface FS1 with a small curvature FCn and a third surface FS3 with a large curvature FCn. The second surface FS2 is disposed between the first surface FS1 and the third surface FS3, and the change in curvature FCn generated at the boundary K12 between the first surface FS1 and the second surface FS2 and the boundary K23 between the second surface FS2 and the third surface FS3 is smaller.

[0092] As a result, the second curved surface FS2 mitigates the sharp change in curvature FCn, thus reducing the change in optical properties caused by the change in curvature FCn and making the distortion of the seen image less noticeable. That is, in the windshield 30 of this embodiment, the large image distortion that may occur in the windshield 30A of the comparative example is less likely to occur.

[0093] As described above, in this embodiment, in addition to the structure that the thickness FT1 in the normal direction of the first curved surface FS1 of the windproof glass 30 is the same as the thickness FT2 in the normal direction of the second curved surface FS2 of the windproof glass 30, it also has a structure in which a second curved surface FS2 with a moderate curvature FCn is arranged between the first curved surface FS1 with a small curvature FCn and the third curved surface FS3 with a large curvature FCn.

[0094] With this structure, in addition to the first surface FS1 with a smaller curvature FCn, the second surface FS2 with a moderate curvature FCn can also be effectively used as the viewing surface VS with less image distortion, increasing the area of ​​the beneficial region in the windshield 30 that can be used as the viewing surface VS. Furthermore, the abrupt changes in curvature FCn at the boundaries of surfaces with different curvatures are mitigated, and the adverse conditions caused by these abrupt changes in curvature FCn (e.g., large image distortion) are suppressed.

[0095] The above-described embodiments can be modified as follows. The above-described embodiments and the following modifications can be combined with each other to implement them within the scope of technical inconsistency.

[0096] The pointer in this application is not limited to the second hand 14. For example, it can be the GMT pointer in a GMT watch, the timing pointer in a chronograph, or a pointer that indicates functional information other than time.

[0097] The windshield 30 of the above embodiment has a single second surface FS2 with a moderate curvature FCn between a first surface FS1 with a small curvature FCn and a third surface FS3 with a large curvature FCn. The number of surfaces with a moderate curvature FCn disposed between the first surface FS1 and the third surface FS3 is not limited to a single one, but can also be multiple. In other words, the second surface in this application can also be multiple surfaces.

[0098] Furthermore, when the second surface in this application comprises multiple surfaces, it is preferable that the curvature of the multiple surfaces gradually increases from the first surface FS1 with a small curvature FCn towards the third surface FS3 with a large curvature FCn. That is, the second surface in this application preferably has a structure in which the curvature gradually increases from the boundary between the first and second surfaces towards the boundary between the second and third surfaces. In this case, it is preferable that the thickness of the multiple surfaces constituting the second surface FC2 is equal.

[0099] For example, in the comparative example windshield 30A, at the boundary between the first surface FS1A with small curvature FCn and the third surface FS3A with large curvature FCn, a sharp change in curvature FCn may occur, resulting in large image distortion.

[0100] For example, in the windshield 30 of this embodiment, a second surface FS2 with a moderate curvature FCn is arranged between the first surface FS1 with a small curvature FCn and the third surface FS3 with a large curvature FCn. Therefore, the sharp change in curvature FCn at the boundary of the surfaces with different curvatures is mitigated, the possibility of large image distortion is suppressed, and the pointer 11 or scale 16 can be seen in a natural state.

[0101] For example, if multiple surfaces with different curvatures are set between the first surface FS1 with small curvature FCn and the third surface FS3 with large curvature FCn, and the curvature changes gradually, the abrupt changes in curvature FCn at the boundaries of the surfaces with different curvatures are mitigated. Therefore, the possibility of large image distortion is further suppressed, and the pointer 11 or scale 16 can be seen in a more natural state. That is, between the first surface FS1 with small curvature FCn and the third surface FS3 with large curvature FCn, the curvature changes gradually, and the change in curvature is further reduced. Therefore, the distortion of the seen image is further reduced, and the visibility of time displays, etc., can be further improved.

[0102] In this embodiment, the scale 16 is configured to be positioned closer to the center C side of the windshield 30 than the boundary K23 of the second curved surface FS2 and the third curved surface FS3, but it is not excluded that the outer end 16a of the scale is positioned slightly closer to the outer edge E side of the windshield 30 than the boundary K23.

[0103] For example, even if approximately 10% of the scale 16 extends towards the outer edge E of the windshield 30 from the boundary K23, and the outer end 16a of the scale is positioned between the boundary K23 and the outer edge E, the effect of image distortion on the scale 16 is minimal, and the image distortion in a top-down view from the Z direction is not easily observed. Similarly, if approximately 10% of the hand 11 (second hand 14) extends towards the outer edge E of the windshield 30 from the boundary K23, and the end 11a of the hand 11 (end 14a of the second hand 14) is positioned between the boundary K23 and the outer edge E, the effect of image distortion on the hand 11 is also minimal, and the image distortion in a top-down view from the Z direction is not easily observed.

[0104] Thus, if the distortion of the image viewed from above in the Z direction is substantially small, it is not limited to the structure in which the entire scale 16 and pointer 11 are positioned closer to the center C side of the windshield 30 than the boundary K23 between the second surface FS2 and the third surface FS3. A portion of the scale 16 and pointer 11 can also be positioned closer to the outer edge E side of the windshield 30 than the boundary K23 between the second surface FS2 and the third surface FS3.

Claims

1. A clock, characterized in that, It includes: dial; A windproof glass, which protects the dial, has multiple curved surfaces with different curvatures; and A pointer, positioned between the dial and the windshield, indicates information other than hours and minutes. The windproof glass has the following features: A first curved surface, having a first curvature and containing the center of the windshield; A second surface, which is adjacent to the first surface, has a second curvature that is larger than the first curvature; as well as A third surface, which is adjacent to the second surface, has a third curvature that is greater than the second curvature. The thickness of the first surface in the normal direction is the same as the thickness of the second surface in the normal direction. In a top view from the dial toward the windshield in a first direction, the tip of the pointer is positioned closer to the center of the windshield than the boundary between the second and third curved surfaces.

2. The clock according to claim 1, characterized in that, The dial also has a scale indicated by the pointer. In the top view, the outer end of the scale is positioned between the boundary of the second and third surfaces and the end of the pointer.

3. The clock according to claim 2, characterized in that, In the top view, the scale does not overlap with the third curved surface.

4. The clock according to claim 1 or 3, characterized in that, The curvature of the second surface gradually increases from the boundary between the first and second surfaces toward the boundary between the second and third surfaces.

5. The clock according to any one of claims 1 to 3, characterized in that, In the top view, the area of ​​the first curved surface in the windshield is the largest.

6. The clock according to any one of claims 1 to 3, characterized in that, The windproof glass is sapphire glass.

Images