JP2011129160A - Keyboard device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a keyboard device that improves luminance of a lamp at the top of a key. <P>SOLUTION: The keyboard device 1 includes: a membrane substrate 50 having contacts 511, 521; a holding plate 20 holding the keytops 10 so as to be moved toward and away from the membrane substrate 50 in a position facing the contacts 511, 521; a light guide plate 40 having light transmittance and guiding light to the keytops 10; and a rubber dome 35 having light transmittance and biasing the keytops 10 in a direction of moving the keytops 10 away from the membrane substrate 50. The light guide plate 40 is disposed closer to the keytops 10 than the membrane substrate 50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a keyboard device with an illumination function used for a notebook computer or a desktop computer.

  As a keyboard capable of visually recognizing a key even in the dark, a keyboard that irradiates light on a key top through a light guide plate is known (see, for example, Patent Document 1).

JP 2002-260478 A

  In the keyboard device described above, the light diffused from the light guide plate is guided to the key top through the substrate holding the key top or the membrane substrate, so that there is a problem that the illumination brightness is low at the key top.

  The problem to be solved by the present invention is to provide a keyboard device capable of improving the luminance of illumination at a key top.

  According to the first aspect of the present invention, the first contact is formed, the first sheet on which the light guide plate is directly laminated, and the second contact facing the first contact through a predetermined interval. A circuit board having a formed second sheet, a spacer laminated between the first sheet and the second sheet, and a key at a position facing the first and second contacts. A holding plate that holds the top so as to be close to and away from the circuit board, a light-transmitting light guide plate that guides light to the key top, a light-transmitting material, and the key top that holds the circuit board. A rubber dome that biases in a direction away from the keyboard, wherein the light guide plate is disposed between the holding plate and the circuit board and closer to the key top than the circuit board. At the same time as the rubber dome. The keyboard device is arranged on the road board side.

  The invention of claim 2 is the keyboard device according to claim 1, wherein the first sheet is made of white polyethylene terephthalate or white polyethylene naphthalate. .

  A third aspect of the invention is the keyboard device according to the first or second aspect, wherein the light guide plate is made of a urethane resin or a silicone resin.

  The invention of claim 4 is the keyboard device according to any one of claims 1 to 3, wherein the rubber dome is directly joined to the light guide plate.

  The invention of claim 5 is the keyboard apparatus according to claim 4, wherein the rubber dome has a refractive index relatively higher than that of the light guide plate.

  A sixth aspect of the present invention is the keyboard apparatus according to the fifth aspect, wherein the rubber dome is made of a silicone-based resin.

  The invention according to claim 7 is the keyboard device according to claim 6, wherein the rubber dome has an index of refraction greater than or equal to the refractive index of the light guide plate and less than or equal to the index of refraction of the rubber dome. A keyboard device characterized by being joined to a light guide plate.

  The invention of claim 8 is the keyboard device according to any one of claims 1 to 7, wherein the holding plate holds the key top via a link mechanism.

  The light guide plate may be made of a material having a Young's modulus of 1000 [MPa] or less, or the light guide plate may be made of a material having a Young's modulus of 300 [MPa] or less. Good.

  In the present invention, since the light guide plate is disposed between the holding plate and the circuit board and closer to the key top side than the circuit board, it is possible to improve the luminance of illumination at the key top.

FIG. 1 is a cross-sectional view showing the overall configuration of the keyboard device according to the first embodiment of the present invention. FIG. 2 is a plan view showing the key top in the first embodiment of the present invention. FIG. 3 is a plan view showing a state where the key top shown in FIG. 2 is illuminated in the dark. FIG. 4 is an enlarged cross-sectional view showing a portion IV in FIG. FIG. 5 is an enlarged cross-sectional view showing a keyboard device according to the second embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view showing the keyboard device according to the third embodiment of the present invention. FIG. 7 is a photograph showing the luminance distribution measurement result of Sample 1. FIG. 8 is a photograph showing spots set in the luminance distribution measurement results shown in FIG. FIG. 9 is a photograph showing the luminance distribution measurement result of Sample 2.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a cross-sectional view showing the overall configuration of the keyboard device according to the present embodiment, FIGS. 2 and 3 are plan views showing key tops according to the present embodiment, and FIG. 4 is an enlarged cross-sectional view showing the IV part of FIG.

  A keyboard device 1 according to the present embodiment is a keyboard used for a notebook computer or the like. As shown in FIG. 1, a key top 10, a holding plate 20, a rubber dome sheet 30, a light guide plate 40, and a membrane substrate are used. 50 and a housing 60.

  As shown in FIG. 2, the key top 10 has a key surface 11 to which characters 12 such as English and Japanese are attached, and when the input person presses the key surface 11 with a finger, the characters Is input to the notebook computer. Instead of the characters 12, numbers, symbols, figures, or the like may be attached to the key surface 11.

  In the present embodiment, on the key surface 11, the character 12 portion is transparent, while the other portions are opaque. For this reason, when light is applied to the key top 10 from below, the light is transmitted only from the portion of the character 12, so that the key can be visually recognized in the dark as shown in FIG. In addition, the part of the character 12 may be opaque and the other part of the key surface 11 may be transparent.

  A large number of such key tops 10 are arranged on the upper surface of the keyboard device 1. As shown in FIG. 4, each key top 10 is held by a holding plate 20 through a link mechanism 15 so as to be movable up and down.

  The link mechanism 15 is a pantograph link mechanism including two arm members 16 and 17. The first arm member 16 and the second arm member 17 intersect in an X shape in a side view.

  The upper end of the first arm member 16 is slidably connected to the lower surface of the key top 10, and the lower end of the first arm member 16 is rotatably connected to the holding plate 20. On the other hand, the upper end of the second arm member 17 is rotatably connected to the lower surface of the key top 10, and the lower end of the second arm member 17 is slidably connected to the holding plate 20.

  When the key top 10 is pushed down, the first arm member 16 rotates about its lower end, and its upper end slides on the lower surface of the key top 10. At the same time, the second arm member 17 rotates about its upper end, and its lower end slides on the holding plate 20.

  Since such a link mechanism 15 is interposed between the key top 10 and the holding plate 20, the key top 10 moves up and down while maintaining the same position (position facing the contacts 511 and 521 of the membrane substrate 50). The key top 10 is prevented from falling off from the keyboard device 1.

  The link mechanism in the present invention is not limited to the above-described pantograph type link mechanism 15. For example, a gear link mechanism is also included in which gears formed at the ends of two arm members are engaged with each other and the arm members are combined in an inverted V shape.

  The holding plate 20 is provided with a pair of protrusions 21 and 22 for one key top 10. The first projection 21 rotatably holds the lower end of the first arm member 16 of the link mechanism 15. On the other hand, the second protrusion 22 is formed with a groove 221 that opens toward the first protrusion 21 and has a depth along the planar direction of the holding plate 20. The lower end of the arm member 17 is slidably inserted.

  In the holding plate 20, an opening 23 is formed between the first protrusion 21 and the second protrusion 22. A rubber dome 35 of the rubber dome sheet 30 protrudes from the opening 23 toward the key top 10.

  The holding plate 20 is laminated on the rubber dome sheet 30. The rubber dome sheet 30 includes a seat body 31 and a rubber dome 35. The sheet body 31 is made of, for example, polyethylene terephthalate (PET). On the other hand, the rubber dome 35 is made of, for example, a transparent silicone resin. The rubber dome 35 is joined to the sheet main body 31 by a leg portion 37 via a transparent adhesive.

  The rubber dome 35 has a convex portion 36 that protrudes downward. On the other hand, an opening 32 is formed in the seat body 31 at a position facing the pressing portion 36 of the rubber dome 35, and the on load of the contacts 511, 521 when the key top 10 is pressed (the contacts 511, 521 come into contact The load that is turned on automatically) is reduced.

  When the key top 10 is pushed down, the rubber dome 35 is pressed and the leg portion 36 is buckled, so that the convex portion 36 of the rubber dome 35 is contacted with the contact point 511 of the membrane substrate 50 via the light guide plate 40. 521 is pressed. On the other hand, when the pressing of the key top 10 is released, the leg portion 37 restores the initial shape by elastic force, the contacts 511 and 521 are separated, and the key top 10 is pushed up by the restoring force of the leg portion 37.

  The rubber dome sheet 30 is laminated on the light guide plate 40. The light guide plate 40 is a transparent film that guides light incident from the light emitting diode 54. The light guide plate 40 is preferably made of a flexible material. Specifically, a material having a Young's modulus of 1 to 1000 [MPa] is preferable, and a flexible material having a Young's modulus of 1 to 300 [MPa] is particularly preferable. Specific examples of the material having such Young's modulus include, for example, urethane resins (Young's modulus: about 5 to 300 [MPa]), silicone resins (Young's modulus: about 1 to 5 [MPa]), and the like. be able to.

  In the present embodiment, since the light guide plate 40 is interposed between the rubber dome 35 and the membrane substrate 50, the light guide plate is made of polycarbonate (Young's modulus: about 2000 to 3000 [MPa]) or acrylic resin (Young's modulus: If it is configured at about 3000 to 3500 [MPa], the light guide plate becomes hard and the contacts 511 and 521 may not be turned on. In contrast, by configuring the light guide plate 40 with a flexible material having a Young's modulus in the above range, the contacts 511 and 521 can be turned on with a small load. The on-load of the contacts 511 and 521 may be reduced depending on the inner diameter of the opening 531 formed in the spacer 53 of the membrane substrate 50 and the thickness of the membrane base material.

  A diffusion portion 41 for diffusing the light in the light guide plate 40 to the outside is provided at a location corresponding to the rubber dome 35 in the light guide plate 40. The diffusion portion 41 is formed by screen printing white ink on the back surface of the light guide plate 40. By diffusing the light by the diffusion portion 41, the light is diffused from the light guide plate 40 to the outside, and the light guide plate 40 emits light upward. The diffusion portion 41 may be formed by laser processing or roughening the surface of the light guide plate 40. Further, the diffusion part 41 may be formed on the upper surface of the light guide plate 40.

  The light guide plate 40 is laminated on the membrane substrate 50. The membrane substrate 50 includes an upper sheet 51, a lower sheet 52, and a spacer 53.

  The upper sheet 51 is made of a flexible white resin film such as white polyethylene terephthalate or white polyethylene naphthalate (PEN). White PET or white PEN can be obtained by mixing PET or PEN with a white pigment or foaming PET or PEN itself.

  A first contact 511 is formed on the lower surface of the upper sheet 51. The first contact 511 is formed by screen-printing silver paste on the upper sheet 51, for example.

  By making the upper sheet 51 on which the light guide plate 40 is directly laminated white, the upper sheet 51 can be provided with the function of a reflector. Thereby, compared with the case where an exclusive reflector is laminated between the light guide plate 40 and the membrane substrate 50, the keyboard device 1 as a whole can be made thinner. In addition, the function of a reflecting plate may be imparted to the upper sheet 51 and the housing 60 by applying white ink on the inner surface of the upper sheet 51 and the housing 60.

  The lower sheet 52 is also made of, for example, polyethylene terephthalate or polyethylene naphthalate. A second contact 521 is formed at a position facing the first contact 511 on the upper surface of the lower sheet 52. Similar to the first contact 511, the second contact 521 is formed, for example, by screen printing a silver paste on the lower sheet 52. The lower sheet 52 does not need to be white and may be transparent. Further, instead of providing the function of the reflecting plate to the upper sheet 51, the upper sheet 51 may be made transparent, and the function of the reflecting plate may be given to the spacer 53, or the upper sheet 51 and the spacer 53 may be made transparent, The lower sheet 52 may be provided with a function of a reflecting plate.

  The spacer 53 is made of the same material as the lower sheet 52. The spacer 53 has an opening 531 corresponding to the first and second contacts 511 and 521. The spacer 53 need not be white and may be transparent like the lower sheet 52.

  In this embodiment, the upper sheet 51 and the lower sheet 52 are laminated via the spacer 53, and the first contact 511 and the second contact 521 are opposed to each other via the opening 531 so as to be able to approach / separate. Yes.

  When the key top 10 is pushed down, the convex portion 36 of the rubber dome 35 presses the upper sheet 51 of the membrane substrate 50 through the light guide plate 40. Thereby, since the upper sheet | seat 51 deform | transforms, the 1st contact 511 contacts the 2nd contact 521, and the contacts 511 and 521 will be in an ON state. On the other hand, when the pressing of the key top 10 is released, the upper sheet 51 is restored to the initial shape by the elastic force, and the contacts 511 and 521 are turned off.

  A light emitting diode (LED) 54 is mounted on the membrane substrate 50. The light-emitting diode 54 is a side-illuminated LED, and is mounted on the membrane substrate 50 so that the irradiation surface 541 faces the incident surface 41 of the light guide plate 40 as shown in FIG.

  When the light emitting diode 54 emits light, the light irradiated from the irradiation surface 541 of the light emitting diode 54 enters the light guide plate 40 through the incident surface 41 and propagates while reflecting in the light guide plate 40.

  And in the location where the diffusion part 41 was formed in the light guide plate 40, the light in the light guide plate 40 diffuses in the diffusion part 41, and leaks upward. The light leaked upward from the light guide plate 40 passes through the rubber dome 35 and reaches the lower surface of the key top 10. This light is transmitted through only the portion of the character 12 in the key top 10 and does not transmit the other portion. Therefore, when the keyboard device 1 is viewed from above, only the portion of the character 12 is lit. For this reason, the key can be visually recognized even in the dark.

  In the present embodiment, as shown in FIG. 1, the membrane substrate 50, the light guide plate 40, the rubber dome sheet 30, and the holding plate 20 are stacked in this order from the lower side, and these are stacked in the housing portion 61 of the housing 60. Contained. The rubber dome sheet 30, the light guide plate 40, and the membrane substrate 50 are sandwiched between the holding plate 20 and the housing 60 by engaging the periphery of the holding plate 20 with the folded portion 62 of the housing 60. ing.

  As described above, in this embodiment, the light guide plate 40 is arranged on the key top 10 side from the membrane substrate 50, thereby guiding the light diffused from the light guide plate 40 to the key top 10 without passing through the membrane substrate 50. Therefore, the brightness of illumination in the key top 10 is improved.

  Further, in the conventional keyboard device, the holding plate is laminated under the membrane substrate, and a through hole for allowing the protrusion of the holding plate to pass through is formed in the membrane substrate. On the other hand, when the through hole is formed in the light guide plate, it causes light leakage, and therefore the light guide plate is laminated below the holding plate. On the other hand, in the present embodiment, the light guide plate 40 is disposed between the holding plate 20 and the membrane substrate 50 and the holding plate is disposed above the light guide plate 40, so that the protrusion 21 of the holding plate 20. , 22 does not need to be formed in the light guide plate 40, and the brightness of the illumination at the key top 10 can be further improved.

<< Second Embodiment >>
FIG. 5 is an enlarged cross-sectional view showing a keyboard device according to the second embodiment of the present invention.

  The present embodiment is different from the first embodiment in that the rubber dome sheet body is not provided and the rubber dome is directly joined to the light guide plate, but the other configurations are the same as the first embodiment. It is the same. Hereinafter, only the points of the keyboard device 1B according to the second embodiment that are different from those of the first embodiment will be described, and portions having the same configurations as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  In the present embodiment, as shown in FIG. 5, the rubber dome 35 is directly joined to the light guide plate 40 by the legs 37 via a transparent adhesive. This adhesive has a refractive index greater than or equal to the refractive index of the light guide plate 40 and less than or equal to the refractive index of the rubber dome 35. Specifically, for example, an adhesive composed of silicone resin or urethane resin. Can be illustrated.

  Here, the urethane resin constituting the light guide plate 40 has a refractive index of about 1.4 to 1.5. On the other hand, the silicone resin constituting the rubber dome 35 has a refractive index of about 4.0 to 4.5, and the refractive index of the rubber dome 35 is higher than the refractive index of the light guide plate 40. Yes.

  In general, when members having different refractive indexes are in close contact, light travels from a member having a low refractive index to a member having a high refractive index. In addition, since the light in the member having a high refractive index is totally reflected and refracted on the contact surface with the member having a low refractive index, the light traveling into the member having a high refractive index returns to the member having a low refractive index. There is no end to it. Therefore, in the present embodiment, the light that has propagated through the light guide plate 40 actively proceeds into the rubber dome 35 through the portion where the leg portion 37 of the rubber dome 35 is joined.

  In the present embodiment, similarly to the first embodiment, the light guide plate 40 is disposed closer to the key top 10 than the membrane substrate 50, so that the light diffused from the light guide plate 40 can be transmitted without passing through the membrane substrate 50. 10, the luminance of the illumination at the key top 10 is improved.

  Further, in the present embodiment, since the light guide plate 40 is disposed between the holding plate 20 and the membrane substrate 50 as in the first embodiment, holes for penetrating the protrusions 21 and 22 of the holding plate 20 are provided. Is not required to be formed on the light guide plate 40, and the luminance of the illumination on the key top 10 can be further improved.

  Furthermore, as described above, in the present embodiment, in addition to the light emission by the diffusion unit 41, the light guide plate 40 is directly guided into the rubber dome 35 using the difference in refractive index. The luminance can be further improved. Moreover, in this embodiment, since the sheet | seat main body 31 of the rubber dome sheet | seat 30 demonstrated in 1st Embodiment becomes unnecessary, the thickness reduction of the keyboard apparatus 1B whole can be achieved.

  In the present embodiment, the rubber dome 35 is directly bonded to the light guide plate 40 with an adhesive, and this adhesive has a refractive index that is equal to or higher than the refractive index of the light guide plate 40 and equal to or lower than the refractive index of the rubber dome 35. Therefore, the light traveling from the light guide plate 40 to the rubber dome 35 is not obstructed.

<< Third Embodiment >>
FIG. 6 is an enlarged sectional view showing a keyboard device according to the third embodiment of the present invention.

  This embodiment is different from the first embodiment in that the structure of the key top and the holding plate is different, but the other configuration is the same as that of the first embodiment. Only the points of the keyboard device 1C according to the third embodiment that are different from the first embodiment will be described below, and portions having the same configurations as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The keyboard device 1C in the present embodiment is a keyboard used for a desktop personal computer.

  From the lower surface of the key top 10C of the keyboard device 1C, an abutment rib 13 and an engagement rib 14 protrude downward. The contact rib 13 is in contact with the rubber dome 35. On the other hand, the engagement rib 14 is engaged with the base 64 of the holding plate 20C.

  Although not particularly illustrated, as in the first embodiment, a character 12 is also attached to the key surface 11 of the key top 10C of the present embodiment, and the character 12 portion on the key surface 11 is transparent. On the other hand, the other part in the key surface 11 is opaque.

  A pedestal 64 is formed on the holding plate 20 </ b> C instead of the first and second protrusions 21 and 22. A protrusion 641 projecting inward is formed on the periphery of the upper opening of the pedestal 64, and the engaging claw 141 of the engaging rib 14 is engaged with the protrusion 641.

  When the key top 10C is pushed down, the rubber dome 35 is deformed, and the convex portion 36 presses the contacts 511 and 521 of the membrane substrate 50 via the light guide plate 40. On the other hand, when the pressing of the key top 10C is released, the rubber dome 35 is restored to the initial shape and pushes up the key top 10C. At this time, the pedestal 64 and the engagement rib 14 are engaged to prevent the key top 10C from falling off the keyboard device 1C.

  In the present embodiment, similarly to the first embodiment, the light guide plate 40 is arranged on the key top 10C side with respect to the membrane substrate 50, so that the light diffused from the light guide plate 40 can be transmitted without passing through the membrane substrate 50. Since it can lead to 10C, the luminance of illumination in the key top 10C is improved.

  Further, in the present embodiment, since the light guide plate 40 is disposed between the holding plate 20 and the membrane substrate 50 as in the first embodiment, holes for penetrating the protrusions 21 and 22 of the holding plate 20 are provided. Need not be formed on the light guide plate 40, and the luminance of the illumination at the key top 10C can be further improved.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the keyboard device 1 </ b> C according to the third embodiment, as described in the second embodiment, the rubber dome may be directly joined to the light guide plate using an adhesive made of a transparent silicone resin.

  The membrane substrate in the present embodiment corresponds to an example of the circuit board in the present invention, the upper sheet in the present embodiment corresponds to an example of the first sheet in the present invention, and the lower sheet in the present embodiment corresponds to the present invention. It corresponds to an example of a second sheet, and the rubber dome in the present embodiment corresponds to an example of an urging member in the present invention.

  Below, the effect of the present invention was confirmed by a sample that further embodied the present invention.

<< Example 1 >>
Sample 1 and Sample 2 below are for confirming the effect of improving the luminance of illumination in the keyboard device in the above-described embodiment.
<Sample 1>
For sample 1, a sample of a keyboard device having the same configuration as that of the first embodiment was produced.

  In the sample of Sample 1, a 100 μm-thick PET film (HS made by Teijin DuPont Films Ltd.) was used as the rubber dome sheet, and a transparent rubber dome (Shin-Etsu Polymer Co., Ltd.) was placed on the PET film. It joined with the adhesive agent (LCR0628A by Toa Gosei Co., Ltd.).

  Moreover, a 200-micrometer-thick urethane sheet (M-FILM-NY02-A by Nippon Matai Co., Ltd.) was used as the light guide plate. Further, a white ink (4700M white manufactured by Jujo Chemical Co., Ltd.) was screen-printed on the lower surface of the urethane sheet to form a diffusion portion.

  Also, a white PET film with a thickness of 100 μm (FW2 manufactured by Teijin DuPont Films, Inc.) is used as the upper sheet of the membrane substrate, and a PET film with a thickness of 100 μm (HS manufactured by Teijin DuPont Films, Inc.) is used as the lower sheet and spacer. Using.

  Moreover, on the upper sheet and the lower sheet, a conductive paste containing a silver filler (DX-351H-30 manufactured by Toyobo Co., Ltd.) is screen-printed, so that the first and second contacts having a thickness of 10 μm are respectively provided. Formed.

  A side-emitting LED (CL-432F manufactured by Citizen Electronics Co., Ltd.) having a length of 2.8 mm, a width of 1.0 mm, and a height of 0.6 mm is applied to the membrane substrate, and a conductive adhesive (3302B manufactured by ThreeBond Co., Ltd.). Implemented using.

  In addition, in the sample of Sample 1, when mounting the LED on the lower sheet, a circuit pattern for LED mounting is formed on the lower sheet, and a through hole for inserting the LED mounted on the lower sheet is provided on the upper sheet. And a spacer.

  The LED of the sample 1 is energized with a current of 100 mA using a low-voltage current generating power supply (R6142 manufactured by Advantest Co., Ltd.), and the luminance distribution of the illumination at the key top in a state where the LED is turned on is a two-dimensional color luminance meter. It measured using (Konica Minolta Sensing Co., Ltd. CA-2000). The brightness distribution measurement result at this time is shown in FIG. Also, spots as shown in FIG. 8 were set for each key, and the average value of the luminance of all spots was calculated. The calculation results are shown in Table 1. In FIG. 8, a solid line frame is a spot.

<Sample 2>
In sample 2, a sample of the keyboard device having the same configuration as that of sample 2 was produced except that the stacking order of each member was changed. That is, in the sample of Sample 2, the light guide plate, the holding plate, the membrane substrate, and the rubber dome sheet were stacked from the lower side in this order (the stacking order described in JP-A-2002-260478 described above).

  In addition, with this change in the stacking order, a reflection sheet (FW2 manufactured by Teijin DuPont Films, Inc.) composed of a white PET film having a thickness of 100 μm was added below the light guide plate. The upper sheet of the membrane substrate was changed to a transparent PET film (HS made by Teijin DuPont Films Ltd.) similar to the lower sheet and spacer. Further, through holes through which the first and second protrusions of the holding plate penetrate were formed in the rubber dome sheet and the membrane substrate.

  For the sample of Sample 2, the LED was turned on in the same manner as Sample 1, and the luminance distribution of illumination at the key top was measured. The luminance distribution measurement result at this time is shown in FIG. Moreover, the same spot as the sample 1 was set to each key, and the average value of the luminance of all the spots was calculated. The calculation results are shown in Table 1 above.

<Discussion>
As shown in FIGS. 7 and 9, the luminance of the key top is improved overall in the sample 1 as shown in FIGS. As shown in FIG. 1, the luminance is improved about twice.

  From this, it can be understood that the luminance of the illumination at the key top is improved by arranging the light guide plate between the holding plate and the membrane substrate and closer to the key top side than the membrane substrate.

<< Example 2 >>
Next, the presence or absence of an increase in the on-load of the keyboard device in the above-described embodiment was confirmed by using Samples 3 to 9 described below.

<Sample 3>
In Sample 3, a keyboard device sample having the same configuration as Sample 1 was prepared, except that a 150 μm-thick urethane sheet (M-FILM-NY02-A manufactured by Nippon Matai Co., Ltd.) was used as the light guide plate. Table 2 shows the configuration of the light guide plate of Sample 3.

With respect to the sample of Sample 3, the load at the time when the contacts of the membrane substrate contacted each other and turned on electrically was measured (on load). The measurement results are shown in Table 3.

<Sample 4>
In Sample 4, a sample of a keyboard device having the same configuration as Sample 1 described above was prepared, except that a 200 μm-thick urethane sheet (M-FILM-NY02-A manufactured by Nippon Matai Co., Ltd.) was used as the light guide plate. did. The structure of the light guide plate of Sample 4 is shown in Table 2 above.

  On load of the sample 4 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Sample 5>
For Sample 5, a keyboard device sample having the same configuration as Sample 1 described above was prepared, except that a 150 μm-thick silicone sheet (Light Guide Film manufactured by Fuji Polymer Industries Co., Ltd.) was used as the light guide plate. The structure of the light guide plate of Sample 5 is shown in Table 2 above.

  On load of the sample 5 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Sample 6>
In Sample 6, a sample of a keyboard device having the same configuration as Sample 1 described above was prepared, except that a 200 μm-thick silicone sheet (Light Guide Film manufactured by Fuji Polymer Industries Co., Ltd.) was used as the light guide plate. The structure of the light guide plate of Sample 6 is shown in Table 2 above.

  On load of the sample 6 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Sample 7>
In Sample 7, a sample of the keyboard device having the same configuration as Sample 1 described above was prepared except that the light guide plate was not provided. That is, in the sample of Sample 7, the rubber dome sheet was directly laminated on the membrane substrate without interposing a light guide plate between the membrane substrate and the rubber dome sheet. The configuration of Sample 7 is shown in Table 2 above.

  On load of the sample 7 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Sample 8>
For Sample 8, a keyboard device sample having the same configuration as Sample 1 described above was prepared, except that a polycarbonate sheet having a thickness of 130 μm (LC1500 manufactured by Idemitsu Kosan Co., Ltd.) was used as the light guide plate. The structure of the light guide plate of Sample 8 is shown in Table 2 above.

  On load of the sample 8 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Sample 9>
In Sample 9, a keyboard device sample having the same configuration as Sample 1 described above was prepared, except that a 200 μm thick soft acrylic sheet (SA-00-R manufactured by CRD Corporation) was used as the light guide plate. . The structure of the light guide plate of Sample 9 is shown in Table 2 above.

  On load of the sample 9 was measured in the same manner as the sample 3. The measurement results are shown in Table 3 above.

<Discussion>
Samples 3 to 6 using a flexible sheet (urethane sheet, silicone sheet) as the light guide plate have values close to those of sample 7 that does not include the light guide plate. On the other hand, in the samples 8 and 9 using a relatively hard sheet (polycarbonate, soft acrylic) as the light guide plate, the on-load is greatly increased as compared with the samples 3 to 7. Samples 8 and 9 are reference examples for confirming the effect of reducing the on-load of the keyboard device.

  From the above, it can be seen that by adopting a urethane sheet or a silicone sheet as the light guide plate, it is possible to reduce the on-load to the same extent as the configuration without the light guide plate.

DESCRIPTION OF SYMBOLS 1, 1B, 1C ... Keyboard apparatus 10, 10C ... Key top 11 ... Key surface 12 ... Character 15 ... Link mechanism 20, 20C ... Holding plate 30 Rubber dome sheet 31 ... Sheet main body 35 ... Rubber dome (biasing member)
40 ... Light guide plate 50 ... Membrane substrate (circuit board)
51. Upper sheet (first sheet)
511: First contact 52: Lower sheet (second sheet)
521 ... Second contact 53 ... Spacer 54 ... LED
60 ... Case

Claims (8)

A first sheet in which a first contact is formed, a first sheet in which the light guide plate is directly laminated, and a second sheet in which a second contact facing the first contact through a predetermined interval is formed. And a circuit board having a spacer laminated between the first sheet and the second sheet,
A holding plate for holding the key top so as to be close to and away from the circuit board at a position facing the first and second contacts;
A light guide plate having light transparency and guiding light to the key top;
A rubber dome having light permeability and urging the key top away from the circuit board; and a keyboard device comprising:
The light guide plate is disposed between the holding plate and the circuit board, on the key top side with respect to the circuit board, and on the circuit board side with respect to the rubber dome. Characteristic keyboard device. The keyboard device according to claim 1,
The keyboard device, wherein the first sheet is made of white polyethylene terephthalate or white polyethylene naphthalate. The keyboard device according to claim 1 or 2,
The said light-guide plate is comprised from urethane type resin or silicone type resin, The keyboard apparatus characterized by the above-mentioned. The keyboard device according to any one of claims 1 to 3,
The keyboard dome, wherein the rubber dome is directly joined to the light guide plate. The keyboard device according to claim 4,
The keyboard device according to claim 1, wherein a refractive index of the rubber dome is relatively higher than a refractive index of the light guide plate. The keyboard device according to claim 5,
The said rubber dome is comprised from silicone resin, The keyboard apparatus characterized by the above-mentioned. The keyboard device according to claim 6,
The keyboard device, wherein the rubber dome is bonded to the light guide plate with an adhesive having a refractive index that is equal to or higher than the refractive index of the light guide plate and equal to or lower than the refractive index of the rubber dome. The keyboard device according to claim 1,
The keyboard apparatus, wherein the holding plate holds the key top via a link mechanism.