Key unit and electronic apparatus

Abstract

To provide a key unit and an electronic apparatus that can be made thin.SOLUTION: A key unit includes a case and a key top. The case has a first frame extending in a predetermined direction, and a second frame extending parallel to the first frame and provided at a predetermined distance from the first frame. The key top has one end supported by the first frame, and a predetermined portion other than the one end is provided so as to be movable in the space between the first frame and the second frame with the one end as a fulcrum.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic device, such as an electronic dictionary, and a key unit. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as a key unit for electronic dictionaries or notebook computers, for example, there is known one in which a plurality of key tops are attached in a predetermined arrangement to a plate-like base member having a plurality of contacts via a rotating shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-86591 A Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple key tops are arranged in layers on a plate-like base member as in the conventional key unit described above, it is difficult to make the key unit sufficiently thin.

[0005] An object of the present invention is to provide a key unit and an electronic device that can be made thin. [Means for solving the problem]

[0006] In one aspect of the present invention, a key unit includes a case and a key top. The case includes a first frame extending in a predetermined direction, and a second frame extending parallel to the first frame and spaced a predetermined distance from the first frame. The key top has one end supported by the first frame, and a predetermined portion other than the one end is movable within a space between the first frame and the second frame with the one end as a fulcrum. Effect of the Invention

[0007] According to one aspect of the present invention, a key unit and an electronic device that can be made thin can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an external perspective view of an electronic dictionary equipped with a key unit according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the key unit of FIG. [Diagram 3] FIG. 3 is an enlarged perspective view of the case of FIG. [Figure 4] FIG. 4 is a partially enlarged perspective view showing an area F4 in FIG. [Diagram 5] FIG. 5 is a partially enlarged perspective view showing a main part of the case in FIG. [Figure 6] 6 is a perspective view showing a key top of the key unit of FIG. 2. FIG. [Figure 7] FIG. 7 is a perspective view of the key top of FIG. 6 as viewed from the back side. [Figure 8] FIG. 8 is an explanatory diagram for explaining the mounting method of the key top of FIG. [Figure 9] FIG. 9 is an explanatory diagram for explaining the mounting method of the key top of FIG. [Figure 10] 10 is an enlarged perspective view showing an engagement recess that engages with the engagement protrusion of FIG. 6. FIG. [Figure 11] 11 is a perspective view showing a state in which the engagement projection of FIG. 6 is engaged with the engagement recess of FIG. [Figure 12] FIG. 12 is a perspective view showing the layout of the front row of key tops and the second row of key tops. [Figure 13] FIG. 13 is a perspective view in which the frame of FIG. 12 is omitted. [Figure 14] FIG. 14 is a perspective view showing a connection structure of a key top in a key unit according to the second embodiment of the present invention. [Figure 15]FIG. 15 is a perspective view showing a connection structure of a key top in a key unit according to the third embodiment of the present invention. [Figure 16] FIG. 16 is a perspective view showing a main part of a key unit according to the fourth embodiment of the present invention. [Figure 17] FIG. 17 is a perspective view showing a state in which the key top of FIG. 16 is pressed in. FIG. [Figure 18] FIG. 18 is a perspective view showing a state in which the key top of FIG. 16 is placed at an initial position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of an electronic dictionary 100, which is an example of an electronic device. FIG. 1 shows a state in which a second housing 4 is opened with respect to a first housing 2 of the electronic dictionary 100. The first housing 2 is formed in a flat rectangular plate shape, and includes a key unit 10 according to a first embodiment of the present invention. The second housing 4 is formed in a flat rectangular plate shape, and includes a display 5. The key unit 10 accepts input operations by a user. The display 5 displays various information for the user and accepts input operations by the user. The display 5 is a so-called touch panel. The electronic dictionary 100 is used, for example, by placing the back surface of the first housing 2 in contact with the top surface of a desk or the like, and the second housing 4 is opened as shown in the figure.

[0010] The electronic dictionary 100 includes a hinge unit 6 that connects the first housing 2 and the second housing 4. The hinge unit 6 rotatably connects the rear end of the first housing 2 and the lower end of the second housing 4. The second housing 4 can be placed in an open position shown in FIG. 1 in which it is open relative to the first housing 2, and in a closed position (not shown) in which the second housing 4 is placed on the top surface of the first housing 2. The open position (rotation angle) of the second housing 4 relative to the first housing 2 can be changed arbitrarily. When the second housing 4 is in the open position, the key unit 10 can be operated and the display 5 can be viewed. When the second housing 4 is in the closed position, the display 5 is placed on top of the key unit 10, and the electronic dictionary 100 is folded.

[0011] In the following description, regardless of the rotational position of second housing 4, the front end side of first housing 2 is defined as the front of electronic dictionary 100, the rear end side where hinge portion 6 is located is defined as the rear of electronic dictionary 100, and the up-down direction of electronic dictionary 100 is defined with the back surface of first housing 2 positioned horizontally. In addition, the left-right direction of electronic dictionary 100 is defined when first housing 2 is viewed from the front.

[0012] As an example, the key unit 10 has 29 key tops 12 arranged in three rows from front to back. The 29 key tops 12 are arranged with almost no gap between adjacent key tops 12 in the front to back and left to right directions. The first housing 2 has a rectangular opening 3 for exposing the 29 key tops 12 of the key unit 10 to the front side.

[0013] The nine key tops 12 in the second row adjacent to the rear of the ten key tops 12 in the front row are respectively arranged between the key tops 12 in the front row. The ten key tops 12 in the third row at the rear are respectively arranged shifted by half a pitch from the key tops 12 in the second row. Therefore, the ten key tops 12 in the front row and the ten key tops 12 in the third row are positioned facing each other in the front and rear with the nine key tops 12 in the second row in between.

[0014] As shown in Fig. 6 and Fig. 7, the key top 12 is a substantially rectangular plate-like shape, and has a surface 12a that is pressed by the user's finger, a back surface 12b opposite to the surface 12a, a tip 12F, and a rear end 12R. The tip 12F and the rear end 12R have end faces perpendicular to the rear surface 12b. The surfaces 12a of the multiple key tops 12 have a ridge line that extends linearly in the left-right direction between the tip 12F and the rear end 12R, and include a flat surface that connects the tip 12F and the ridge line and a flat surface that connects the ridge line and the rear end 12R. The surfaces 12a of the multiple key tops 12 form the surface of the key unit 10.

[0015] The back surfaces 12b of the multiple key tops 12 are arranged on the same flat imaginary surface when all the key tops 12 are arranged in the initial positions shown in Fig. 1. The tips 12F and rear ends 12R of the key tops 12 in each row are aligned in a straight line in the left-right direction. The rear ends 12R of the multiple key tops 12 in the front row and the tips 12F of the multiple key tops 12 in the second row are close to each other with almost no gaps, and the rear ends 12R of the multiple key tops 12 in the second row and the tips 12F of the multiple key tops 12 in the third row are also close to each other with almost no gaps.

[0016] As shown in Fig. 2, the key unit 10 includes the multiple key tops 12 described above, as well as a circuit board 1, a contact rubber sheet 7, and a case 11. The case 11 holds the rear ends 12R of the multiple key tops 12 so that they can rotate independently, and is attached in the above-mentioned arrangement. The contact rubber sheet 7 is then placed on top of the circuit board 1, and the case 11 with the multiple key tops 12 is placed on top of the contact rubber sheet 7. Most of the volume of the multiple key tops 12 is placed within the thickness of the case 11, and there is almost no portion that overlaps with the case 11 vertically.

[0017] The circuit board 1 has 29 contacts (not shown) at positions facing respectively below the multiple key tops 12. The contact rubber sheet 7 has 29 substantially cylindrical bulging portions 8 at positions facing respectively below the multiple key tops 12. In other words, the multiple bulging portions 8 of the contact rubber sheet 7 overlap the multiple contacts of the circuit board 1, and the multiple key tops 12 overlap the multiple bulging portions 8.

[0018] With the key unit 10 assembled, the protruding tips of the multiple bulging portions 8 of the contact rubber sheet 7 come into contact with the rear surfaces 12b of the multiple key tops 12, and the bulging portions 8 are slightly compressed in the vertical direction due to elastic deformation, and the key tops 12 are biased upward by the restoring force of the bulging portions 8. In other words, with the key unit 10 assembled, the bulging portions 8 of the contact rubber sheet 7 have a thickness (vertical protruding height) that is sufficient to bias the opposing key tops 12 upward.

[0019] The bulging portion 8 is formed by partially bulging the contact rubber sheet 7 toward the key top 12. The contact rubber sheet 7 has a carbon conductor (not shown) applied to its back surface (the inner surface of the bulging portion 8) on the circuit board 1 side. The contact rubber sheet 7 can be formed of an elastic material such as silicone rubber or elastomer.

[0020] When the user presses the surface 12a of the key top 12 downward, the carbon conductor on the inner surface of the bulging portion 8 of the contact rubber sheet 7 conducts the contact of the circuit board 1, and key input is performed. When the user releases his / her finger from the surface 12a of the key top 12, the restoring force of the bulging portion 8 urges the key top 12 upward and returns it to its initial position.

[0021] As shown in FIG. 3, the case 11 has a frame portion 13 and three frames 14, 15, and 16. The frame portion 13 is formed in a rectangular frame shape sized to fit inside the opening 3 of the first housing 2. The frame portion 13 has a front portion 13F and a rear portion 13R that are spaced apart from each other in the front-rear direction and extend in the left-right direction. The three frames 14, 15, and 16 are provided further inside the frame portion 13. The front portion 13F of the frame portion 13 and the three frames 14, 15, and 16 are, for example, rod-shaped frames with a substantially rectangular cross section over their entire length. The case 11 can be formed, for example, by integral molding using resin.

[0022] Frame 14, which is the frontmost of the three frames 14, 15, and 16, is disposed between the frontmost key top 12 and the second row key top 12, with a specified distance behind front portion 13F of frame portion 13. Frame 15 is disposed between the second row key top 12 and the third row key top 12, with a specified distance behind frame 14. Frame 16 is connected to rear portion 13R of frame portion 13 at the rear end side of the third row key top 12, with a specified distance behind frame 15.

[0023] That is, the three frames 14, 15, and 16 are arranged parallel to each other and spaced apart from each other in the front and rear, and extend over the entire length of the frame portion 13 in the left-right direction. Note that there are two plate-like portions 11L and 11R on the inside of both left and right ends of the frame portion 13, which do not have key tops 12. The two plate-like portions 11L and 11R are located between the frames 14 and 15.

[0024] As shown in Figs. 4 and 5, the frames 14, 15, and 16 have a plurality of pairs of bearing recesses 17L, 17R for rotatably mounting two pivot shafts 22L, 22R (Fig. 7) protruding from the rear end 12R of the key top 12. The frames 14, 15 also have a plurality of engagement recesses 18 for engaging the engagement protrusions 24 (Figs. 6 and 7) protruding from the tip 12F of the key top 12. A plurality of engagement recesses 18 are also provided in the front portion 13F of the frame member 13 for engaging the engagement protrusions 24 of the front row of key tops 12. The engagement protrusions 24 of the key top 12 are an example of an abutting portion, and the frames 14, 15, and the engagement recesses 18 provided in the front portion 13F of the frame member 13 are an example of an abutted portion. The frames 14, 15 each have a plurality of pairs of bearing recesses 17L, 17R and a plurality of engagement recesses 18 at positions shifted in the longitudinal direction. The pairs of bearing recesses 17L, 17R have the same structure, and the engaging recesses 18 also have the same structure. Therefore, in the following description, the bearing recesses 17L, 17R and the engaging recesses 18 provided in the frame 15 will be representatively described.

[0025] As shown in Figs. 6 and 7, the key top 12 includes two rotation shafts 22L, 22R and an engagement protrusion 24. The key top 12 is formed in a substantially rectangular plate shape, and the two rotation shafts 22L, 22R protrude from the rear end 12R of the key top 12. The two rotation shafts 22L, 22R are provided spaced apart in the left-right direction of the key top 12. The engagement protrusion 24 protrudes from the tip 12F of the key top 12. The engagement protrusion 24 is provided at the center of the key top 12 in the left-right direction. The key top 12 including the two rotation shafts 22L, 22R and the engagement protrusion 24 can be formed, for example, by integral molding using resin.

[0026] The key top 12 has a shape that is symmetrical with respect to an imaginary central plane that passes through the center in the left-right direction and extends in the up-down direction. Therefore, the two rotation shafts 22L and 22R also have shapes that are symmetrical with respect to the imaginary central plane. Therefore, the left rotation shaft 22L will be mainly described here as a representative, and the description of the right rotation shaft 22R will be omitted.

[0027] The pivot shaft 22L is suspended downward from the back surface 12b near the rear end 12R of the key top 12 at a position spaced to the left of the left-right center of the key top 12. The pivot shaft 22L has a substantially rectangular block-shaped support portion 22a protruding downward from the back surface 12b of the key top 12, and a substantially cylindrical shaft portion 22b extending rightward from the lower end of the support portion 22a toward the left-right center of the key top 12. The shaft portions 22b of the left and right pivot shafts 22L and 22R are coaxially arranged.

[0028] 6 and 7, the engagement protrusion 24 has a support portion 24a protruding downward from the back surface 12b near the tip 12F at the center in the left-right direction of the key top 12, and an engagement portion 24b protruding forward from a side surface 241 (described later) of the support portion 24a. The support portion 24a is formed in a triangular prism shape whose cross section is a right-angled isosceles triangle. The engagement portion 24b is formed in a substantially quadrangular pyramid shape having a flat top surface 248 at the top.

[0029] The support portion 24a has a flat side surface 241 that is a continuous axial line of one short side sandwiching the right angle of the right-angled isosceles triangle in the cross section, and a flat side surface 242 that is a continuous axial line of the other short side sandwiching the right angle of the right-angled isosceles triangle in the cross section. One side surface 241 of the support portion 24a is perpendicular to the back surface 12b of the key top 12 and is disposed flush with the front end of the key top 12, and the other side surface 242 is integrally protruded from the back surface 12b of the key top 12 so as to be connected to the back surface 12b of the key top 12.

[0030] The engagement portion 24b has a flat rectangular bottom surface 243 extending horizontally and a joint surface 244 extending vertically upward from the rear end edge of the bottom surface 243. The joint surface 244 is one side surface of a quadrangular pyramid, and is a surface that connects to one side surface 241 of the support portion 24a. The lower end of the joint surface 244 coincides with the lower end of the side surface 241 of the support portion 24a. The upper end of the joint surface 244 is located slightly below the back surface 12b of the key top 12.

[0031] In addition, the engagement portion 24b has three inclined surfaces 245, 246, and 247 that are inclined so as to converge from the remaining three sides of the bottom surface 243 toward the apex of the quadrangular pyramid. The apex surface 248 near the top end of the quadrangular pyramid where the four surfaces 244, 245, 246, and 247 of the engagement portion 24b join is a surface that is parallel to the back surface 12b of the key top 12 and is located slightly below the back surface 12b.

[0032] 4, the two bearing recesses 17L, 17R of the frame 15 that receive the two rotation shafts 22L, 22R of the key top 12 have shapes that are symmetrical with respect to an imaginary plane perpendicular to the frame 15. Therefore, here, only the left bearing recess 17L will be described, and a description of the right bearing recess 17R will be omitted.

[0033] The bearing recess 17L is a recess for fitting the left rotating shaft 22L of the key top 12. The bearing recess 17L has a cylindrical bearing portion 171 into which the shaft portion 22b of the rotating shaft 22L is press-fitted, and a groove portion 172 for receiving the support portion 22a of the rotating shaft 22L. The groove portion 172 extends upward from the left end of the bearing portion 171, and its lower end is connected to the bearing portion 171. The bearing portion 171 opens to the front surface 15a of the frame 15, and is located between the upper surface 15c and the lower surface 15d of the frame 15. The groove portion 172 opens to the front surface 15a and the upper surface 15c of the frame 15.

[0034] When attaching the pivots 22L, 22R of the key top 12 to the bearing recesses 17L, 17R of the frame 15, the key top 12 is attached from the back side of the case 11 as shown in Fig. 8. In this case, the key top 12 is first placed in the illustrated position with the pivots 22L, 22R positioned upward, and then the key top 12 is moved backward in this position, and the shaft portions 22b of the pivots 22L, 22R are pressed into the bearing recesses 17L, 17R of the frame 15, and the shaft portions 22b are fitted into the bearing portions 171. This state is shown on the right side of Fig. 8.

[0035] 9, the tip 12F of the key top 12 is rotated upward around the shaft portion 22b, the support portions 22a of the rotation shafts 22L, 22R are inserted into the groove portions 172 of the bearing recesses 17L, 17R, and the engagement protrusion 24 on the tip 12F of the key top 12 is engaged with the engagement recess 18 of the frame 14. When the key unit 10 is in an assembled state, the restoring force of the bulging portion 8 of the contact rubber sheet 7 presses the engagement protrusion 24 against the engagement recess 18. The engagement between the engagement protrusion 24 and the engagement recess 18 prevents the key top 12 from jumping out upward.

[0036] As shown in Fig. 10, the engagement recess 18 of the frame 15, which engages with the engagement protrusion 24 of the key top 12, is a recess that opens to the rear surface 15b and the bottom surface 15d of the frame 15. The engagement recess 18 has a first portion 18a that is a rectangular parallelepiped having a predetermined thickness in the vertical direction, and a second portion 18b that is substantially pyramidal and into which the engagement protrusion 24 of the key top 12 fits. A cross section of the first portion 18a cut at an arbitrary height position on a horizontal plane is a rectangle that is slightly larger than the bottom surface 243 of the engagement protrusion 24. The second portion 18b is continuous with the upper portion of the first portion 18a.

[0037] The inner surface of the second portion 18b is continuous with the inner surface of the first portion 18a. The second portion 18b has, on its inner surface, an inclined receiving surface 185 that comes into surface contact with the inclined surface 245 of the engagement protrusion 24, an inclined receiving surface 186 that comes into surface contact with the inclined surface 246 of the engagement protrusion 24, an inclined receiving surface 187 that comes into surface contact with the inclined surface 247 of the engagement protrusion 24, and a rectangular bottom surface 188 that comes into surface contact with the top surface 248 of the engagement protrusion 24. The three inclined receiving surfaces 185, 186, and 187 are inclined in a direction converging from the inner surface of the first portion 18a toward the bottom surface 188. The bottom surface 188 of the second portion 18b of the engagement recess 18 is located slightly below the upper surface 15c of the frame 15. In other words, there is a thin portion 15e between the bottom surface 188 of the second portion 18b and the upper surface 15c of the frame 15.

[0038] 11 shows the state in which the engagement protrusion 24 of the key top 12 is engaged with the engagement recess 18 of the frame 15. When the engagement protrusion 24 is engaged with the engagement recess 18, the inclined surface 245 of the engagement protrusion 24 and the inclined receiving surface 185 of the engagement recess 18 come into surface contact, the inclined surface 246 of the engagement protrusion 24 and the inclined receiving surface 186 of the engagement recess 18 come into surface contact, and the inclined surface 247 of the engagement protrusion 24 and the inclined receiving surface 187 of the engagement recess 18 come into surface contact. At this time, the top surface 248 of the engagement protrusion 24 faces the bottom surface 188 of the engagement recess 18, and the two may or may not come into contact with each other.

[0039] When the key unit 10 is assembled, the key top 12 is biased upward by the bulging portion 8 of the contact rubber sheet 7, so that the engagement protrusion 24 is pressed upward toward the engagement recess 18. Therefore, the three sets of inclined surfaces that are inclined in a direction converging toward the pressing direction (upward) press against each other and come into close contact. At this time, the surface where the engagement protrusion 24 and the engagement recess 18 come into contact has a sufficiently large area, so that the engagement protrusion 24 can be stably engaged with the engagement recess 18.

[0040] On the other hand, if the engagement protrusion is made into a plate-like shape having a thickness in the vertical direction and no inclined surface is provided, the engagement protrusion needs to have a sufficient thickness in the vertical direction to ensure sufficient mechanical strength of the engagement protrusion. In this case, the vertical thickness of the engagement protrusion affects the vertical thickness of the key unit 10. In other words, in order to press the key top 12 to make the contact of the circuit board 1 conductive, the key top 12 needs a stroke in the vertical direction, and it is necessary to prevent the engagement protrusion from interfering with the contact rubber sheet 7 of the circuit board 1 when the key top 12 is pressed to the position where the contact is conductive. For this reason, if the thickness of the engagement protrusion is increased, the vertical thickness of the frame 15 needs to be increased accordingly, and the key unit 10 becomes thicker.

[0041] In the key unit 10 of this embodiment, since the engagement recess 18 of the frame 15 has the first portion 18a, when the engagement protrusion 24 of the key top 12 is engaged with the engagement recess 18 (as shown in FIG. 11), a vertical step 18c is formed between the bottom surface 243 of the engagement protrusion 24 and the lower surface 15d of the frame 15. This step 18c has a vertical length equivalent to the stroke of the key top 12 for pressing the key top 12 to conduct the contact of the circuit board 1. Therefore, when the key top 12 is pressed, the bottom surface 243 of the engagement protrusion 24 does not protrude below the lower surface 15d of the frame 15, and the bottom surface 243 does not contact the contact rubber sheet 7. On the other hand, since the joint surface 244 of the engagement protrusion 24 is integrated with the tip 12F of the key top 12, the engagement protrusion 24 can have sufficient mechanical strength. The inclined surfaces 245, 246, and 247 of the engagement protrusion 24 are configured to enable the movement of the key top 12 within the vertical width of the frame 15, and are configured to contribute to making the key unit 10 thinner.

[0042] As shown in FIG. 12, for example, when focusing on the frame 14 arranged between the key top 12 in the front row and the key top 12 in the second row, one frame 14 has a plurality of pairs of bearing recesses 17L, 17R for holding the pivot shafts 22L, 22R of the key top 12 in the front row, and an engagement recess 18 for engaging the engagement protrusion 24 of the key top 12 in the second row. In addition, the rear end 12R of the key top 12 in the front row is arranged overlapping on the upper surface 14c of the frame 14. Therefore, the rear end 12R of the key top 12 in the front row and the tip 12F of the key top 12 in the second row are arranged close to each other with almost no gap. In other words, when the key unit 10 is viewed from the direction shown in FIG. 1, the frames 14, 15, and 16 cannot be seen between the plurality of key tops 12.

[0043] As described above, most of the key top 12 can be contained within the thickness of the case 11, but the part on the rear end 12R side overlapping the upper surface 14c of the frame 14 exceeds the thickness of the case 11. However, since the front surface 12a of the key top 12 overlapping the upper surface 14c of the frame 14 is inclined toward the rear surface 12b toward the rear end 12R, the part close to the rear end 12R is thinner. Therefore, the thickness of the key unit 10 can be kept slightly larger than the thickness of the case 11.

[0044] 13, when the frames 14 and 15 are removed, it can be seen that the engagement protrusion 24 protruding from the tip 12F of the second row key top 12 on the rear end 12R side of the front row key top 12 overlaps the back surface 12b of the front row key top 12. As described above, by arranging the rear end 12R of the front row key top 12 and the tip 12F of the second row key top 12 close to each other, the engagement protrusion 24 of the second row key top 12 is arranged overlapping under the front row key top 12.

[0045] The above-mentioned layout of the multiple key tops 12 in the front row and the multiple key tops 12 in the second row is also the same for the multiple key tops 12 in the second row and the multiple key tops 12 in the third row, thereby realizing a close arrangement of all 29 key tops 12 in the front-to-rear direction.

[0046] As described above, according to the key unit 10 of the first embodiment, most of the volume of the multiple key tops 12 can be arranged within the thickness of the case 11, making it possible to reduce the thickness of the key unit 10. Also, according to the first embodiment, multiple sets of bearing recesses 17L, 17R are provided in the frames 14, 15, 16 of the case 11, and multiple key tops 12 are directly attached to the case 11, so there is no need to provide a structure for rotatably attaching the key tops 12 separately from the case 11, and the number of parts constituting the key unit 10 can be reduced, making it possible to manufacture the key unit 10 at low cost.

[0047] Also, according to the first embodiment, when attaching the key tops 12 to the frames 14, 15, and 16 of the case 11, it is only necessary to press the rotation shafts 22L, 22R of the key tops 12 into the bearing recesses 17L, 17R of the frames 14, 15, and 16 from the back side of the case 11, thereby reducing the number of assembly steps. Also, the case 11 with multiple key tops 12 attached can be handled as a single unit, making it easier to assemble the key unit 10.

[0048] The key unit 10 of the first embodiment described above has a configuration in which the pivot shafts 22L, 22R provided at the rear end 12R of the key top 12 are press-fitted into the bearing recesses 17L, 17R provided in the case 11, but the pivot shafts and the bearing recesses may be reversed. Figure 14 shows the mounting structure of the key top 30 of the key unit according to the second embodiment of the present invention.

[0049] In the second embodiment, two protrusions 34L, 34R are provided protruding from the rear end of the key top 30, and the support shafts 32L, 32R of the frame 15 are press-fitted into the engagement recesses 34a of the protrusions 34L, 34R. According to the second embodiment, the key top 30 is moved backward toward the frame 15 while being placed in the illustrated posture, so that the two support shafts 32L, 32R of the frame 15 can be press-fitted into the engagement recesses 34a of the two protrusions 34L, 34R of the key top 30. Therefore, compared to the first embodiment described above, a process of rotating the key top after pressing the shafts into the recesses is not required, and the number of assembly steps can be reduced.

[0050] In the above-mentioned first and second embodiments, the key tops 12, 30 are attached to the frame 15 so as to be rotatable about an axis extending in the left-right direction. However, an attachment structure that does not include a rotation axis may be adopted as in the third embodiment shown in Fig. 15. The attachment structure of the third embodiment includes two connection pieces 44L, 44R integrally provided at the rear end of the key top 40 and two support protrusions 42L, 42R provided on the frame 15.

[0051] The support protrusions 42L, 42R of the frame 15 are generally cylindrical protrusions protruding downward from the frame 15. The connection pieces 44L, 44R of the key top 40 are formed in a rectangular plate shape curved in an L shape toward the frame 15, and each has a fitting hole 44a at the tip side in the protruding direction. The fitting hole 44a penetrates the connection pieces 44L, 44R in the up-down direction.

[0052] When attaching the key top 40 to the frame 15, the key top 40 is moved upward from the rear surface side of the case 11, and the two support protrusions 42L, 42R of the frame 15 are press-fitted into the fitting holes 44a of the two connection pieces 44L, 44R of the key top 40. In this state, the key top 40 becomes movable in the up and down direction due to the elastic deformation of the two connection pieces 44L, 44R of the key top 40.

[0053] According to the third embodiment, compared to the first and second embodiments, the vertical width equivalent to the diameter of the pivot shaft is not required, so the mounting structure itself can be made thinner in the vertical direction. Therefore, it can be said to be a more advantageous structure in terms of making the key unit thinner. Also, the mounting of the key top 40 to the frame 15 can be made easier compared to the first embodiment, the number of assembly steps can be reduced, and the manufacturing cost can be kept down.

[0054] Furthermore, in the first to third embodiments described above, the engagement protrusions 24 are provided at the tips of the key tops 12, 30, and 40, but the engagement protrusions 24 can be omitted by adopting a configuration in which the rear end 12R of the key top 12 overlaps the upper surface 15c of the frame 15 as in the first embodiment. Figures 16 to 18 show a fourth embodiment.

[0055] As shown in Fig. 16, according to the fourth embodiment, the multiple key tops 50 do not have an engagement protrusion at the tip. As shown in Fig. 17, when the finger is released from the pressed state of the key top 50, the key top 50 is urged upward by the bulging part 8 of the contact rubber sheet 7 and is returned to the initial position as shown in Fig. 18. In this case, the key top 50 is not returned to the initial position determined by the engagement between the engagement protrusion and the engagement recess, but is arranged in the initial position determined by the contact of the lower surface 50b behind the rotation center of the key top 50 with the upper surface 15c of the frame 15.

[0056] In other words, by abutting the lower surface 50b, which is located behind the rotation center of the key top 50, against the upper surface 15c of the frame 15, further upward rotation of the key top 50 can be prevented, and the key top 50 can be placed in its initial position.

[0057] According to the fourth embodiment, since no engagement protrusion is provided at the tip of the key top 50, the engagement protrusion does not come into contact with the contact rubber sheet 7 when the key top 50 is pressed down as shown in Fig. 17, and the frame 15 can be made thinner. In other words, according to the fourth embodiment, the key unit 10 can be made thinner compared to the above-mentioned first to third embodiments.

[0058] Incidentally, rather than omitting the engagement protrusion as in the fourth embodiment, taking into consideration the reduction in mechanical strength, it is also possible to make the engagement protrusion thinner and add a configuration in which the lower surface of the engagement protrusion abuts against the upper surface of the frame at the rear end side of the pivot center of the key top.

[0059] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. In addition, the embodiments may be implemented in appropriate combination, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [Explanation of symbols]

[0060] 1...circuit board, 2...first housing, 3...opening, 4...second housing, 6...hinge portion, 7...contact rubber sheet, 8...bulging portion, 10...key unit, 11...case, 12...key top, 12a...surface, 12b...back, 12F...tip, 12R...rear end, 13...frame portion, 13F...front portion, 13R...rear portion, 14, 15, 16...frame, 15a...front surface, 15b...rear surface, 15c...upper surface, 15d...lower surface, 15e...thin portion, 17L, 17R...bearing recess, 171...bearing portion, 172...groove portion, 18...engagement recess, 18a...first portion, 18b...second portion, 185, 186, 187...inclined receiving surface, 188...Bottom surface, 22L, 22R...Rotation shaft, 22a...Support part, 22b...Shaft part, 24...Engagement protrusion, 24a...Support part, 24b...Engagement part, 241, 242...Side surface, 243...Bottom surface, 244...Joint surface, 245, 246, 247...Slope surface, 248...Top surface, 100...Electronic dictionary.

Claims

1. a case having a first frame extending in a predetermined direction and a second frame extending parallel to the first frame and spaced a predetermined distance from the first frame; a key top having one end supported by the first frame, the key top being provided so that a predetermined portion other than the one end can move within a space between the first frame and the second frame with the one end as a fulcrum; A key unit equipped with

2. The key top has a contact portion at the other end portion on the second frame side, the second frame has a contact portion provided on a bottom surface side of the second frame and capable of contacting the contact portion; The key unit according to claim 1 .

3. The contact portion of the key top has a contact surface inclined with respect to a moving direction of the key top, The abutted portion of the second frame has a receiving surface that comes into surface contact with the abutment surface. The key unit according to claim 2 .

4. The receiving surface includes a plurality of receiving surfaces inclined in different directions, and the abutment surface includes a plurality of abutment surfaces inclined in the same direction as the receiving surfaces. The key unit according to claim 3.

5. a rotation shaft for rotatably mounting the one end of the key top to the first frame; The key unit according to claim 1 .

6. The rotation axis is disposed within a thickness of the first frame. The key unit according to claim 5.

7. the case has a third frame provided parallel to the second frame at a predetermined interval on an opposite side of the first frame with respect to the second frame, The key top includes a first key top having one end supported by the first frame and the other end on the second frame side, and a second key top having one end supported by the second frame and a predetermined portion other than the one end being movable within a space between the second frame and the third frame with the one end as a fulcrum. The key unit according to claim 1 .

8. the first key top has a contact portion at the other end, the second frame has a contact portion provided on a bottom surface side of the second frame and capable of contacting the contact portion of the first key top, and a support portion supporting the one end portion of the second key top; The key unit according to claim 7.

9. The contact portion of the first key top is a protrusion that overlaps with the one end portion of the second key top. The key unit according to claim 8.

10. An electronic device comprising the key unit according to claim 1 .

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