JP2010170973A - Light guide and push-button switch member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide capable of making a display part and/or an input part easy to view with enhanced luminance, and a push-button switch member using the light guide. <P>SOLUTION: The light guide 100 to be disposed oppositely on the reverse side of a display part or input part that is an illumination object, which receives and guides light from a plurality of light sources to the inside, and emits light toward the display part or input part to illuminate it includes: a first light reflecting layer 10 provided in a position facing the display part or input part, on the top surface of a light transmissive light guide plate 12 that is an essential part of the light guide 100, to cover the area other than an opening 5 for emitting light passed through the light guide plate 12; and a second light reflecting layer 20 which covers the reverse surface of the light guide plate 12 to reflect the light passed through the light guide plate 12 to the inside while reducing emission of the light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light guide suitably used for an electronic device and the like, and a push button switch member using the light guide.

  In recent years, in electronic devices such as mobile phones and portable information terminal devices, it has been required to increase the visibility of the display unit and / or the input unit of the electronic device in a dark place. Further, in a small electronic device that is becoming increasingly multifunctional, a plurality of applications are often incorporated in one electronic device, and it is desired that the display unit and / or the input unit can be easily identified for each application. Yes.

  In response to this problem, a push button switch member used for illumination of the following electronic devices has been proposed. For example, a plurality of operation keys for operating the device, a plurality of switching elements that are disposed below the plurality of operation keys and that are switched by pressing the operation keys, and disposed between the operation keys and the switching elements A pushbutton switch member that is provided with a light guide that is operated by introducing light incident from a light source disposed on a side surface or a peripheral portion of the light guide and diffusing the light inside the light guide. An invention is known in which light is projected toward the lower surface and emitted toward the front surface of the operation key. (For example, see Patent Document 1).

  The following push button switch members are also known. It is a member for a push button switch having a key top portion and a base portion integrally formed of transparent silicone rubber, and uses a light guide disposed immediately below the base portion to form a push button switch member and a circuit board. The key top portion is illuminated by supplying light from a light emitting source such as an LED (for example, see Patent Document 2).

JP 2001-167655 A (claims, etc.) Japanese Patent Laid-Open No. 08-273474 (claims)

  However, the conventional illuminated pushbutton switch member has the following problems. In the case of the member for a push button switch disclosed in Patent Literature 1 and Patent Literature 2, it is possible to achieve illumination with high brightness of the push button portion to some extent. However, in such a pushbutton switch member, light is incident from the side end face of the light guide, and light is propagated throughout the lightguide using the internal reflection, so the light emission surface corresponding to the pushbutton portion Light emitted from other places leaks to the outside. For this reason, it is difficult to uniformly illuminate the surface of the push button portion, and there is a problem that uneven illumination or uneven brightness tends to occur. In addition, since only a part of the light from the light source can contribute to improving the visibility of the push button portion, even when large power consumption is used, the luminance is low and the visibility of the push button portion is reduced.

  Accordingly, the present invention has been made to solve the above-described problems, and the object of the present invention is to provide a light guide and a display unit and / or an input unit with higher luminance and easy to visually recognize. The object is to provide a member for a push button switch using the light guide.

  In order to achieve the above object, the present invention is arranged opposite to the back side of a display unit or input unit to be illuminated, receives light from a plurality of light sources, guides it to the inside, and transmits light toward the display unit or input unit. A light guide that emits light to illuminate the light guide, and passes through the inside of the light-transmissive light guide plate at a position on the front side of the light-transmissive light guide plate that is the main part of the light guide and facing the display unit or the input unit. Covers the first light reflecting layer that covers the area other than the opening for emitting the incident light and the back side surface of the translucent light guide plate, and reduces the emission of light that has passed through the translucent light guide plate The light guide has a second light reflecting layer for reflecting light into the inside.

  By setting it as the above light guides, it becomes a light guide with a high brightness | luminance and easy visual recognition of a display part and / or an input part. That is, the first light reflection layer and the second light reflection layer that cover the region other than the opening are formed, so that when the light from the light source is guided through the translucent light guide plate, the first light reflection layer is formed. The light reflecting layer and the second light reflecting layer have a function of reflecting light to be emitted to the inside and returning the light again into the translucent light guide plate. For this reason, the ratio of light leakage from locations other than the opening is extremely low, and light is easily emitted only from the opening. Therefore, the light from the light source can contribute to improving the visibility of the display unit and / or the input unit. That is, light energy can be used without waste and the luminance can be further increased.

  In another invention, in addition to the above-described invention, the light-transmitting light guide plate is disposed at a position facing the display unit or the input unit on at least one of the front side and the back side. The light guide is provided with a light diffusing portion for diffusing light that has passed through the inside and emitting the light from the opening.

  By using such a light guide, light from the light source is reflected toward the surface of the light transmissive light guide plate by the light diffusing portion of the light transmissive light guide plate, so that the light is more efficiently emitted through the opening. be able to.

  In addition to the above-described invention, another invention is to further reduce light emission from the outer surface of the first light reflecting layer and / or the outer surface of the second light reflecting layer. The light guide is further provided as a light guide.

  By setting it as such a light guide, the brightness | luminance itself of an opening part or the brightness | luminance of an opening part is visually recognized relatively high with respect to the circumference | surroundings.

In addition to the above-described invention, another invention is a light guide in which a filter layer for shielding light of a specific color is provided in the opening.

  By providing such a light guide, by providing a filter layer in the opening, light of a specific color can be shielded and only a desired display can be visually recognized.

  In another invention, in addition to the above-described invention, the opening is provided with a display layer having an overlapping display area in which at least the first display area and the second display area partially overlap, The first display area excluding the overlapping display area has the first filter layer, the second display area excluding the overlapping display area has the second filter layer, and the first filter layer has the first filter layer. The second filter layer is a layer that is easier to transmit light in the first predetermined wavelength band than the second filter layer and is less likely to transmit light in the second predetermined wavelength band than the second filter layer. Is a layer that is easier to transmit light in the second predetermined wavelength band than the first filter layer and is less likely to transmit light in the first predetermined wavelength band than the first filter layer, and has an overlapping display region. Is a laser that transmits both light in the first predetermined wavelength band and light in the second predetermined wavelength band. It is set to Togaido.

  By adopting such a light guide, the display layer provided in the opening visually recognizes only the first display area even though the first display area and the second display area overlap. It is also possible to make only the second display area visible. That is, the display can be switched. In addition, since the displays can be arranged in an overlapping manner, the display can be enlarged. Here, at least the first display area and the second display area partially overlap each other in the areas other than the first display area and the second display area. This also includes the case of overlapping the display area.

  In another invention, in addition to the above-described invention, the overlapping display region is a light guide including a third filter layer that transmits both light in the first predetermined wavelength band and light in the second predetermined wavelength band. Yes.

  By using such a light guide, it is possible to make only the first display area visible even though the first display area and the second display area overlap, Only the area can be visually recognized. In addition, the light intensity and color tone of the overlap display area and the first display area excluding the overlap display area, or the overlap display area and the second display area excluding the overlap display area can be made similar. Therefore, the appearance is good.

  In another invention, in addition to the above-described invention, the overlapping display area includes a first dispersed arrangement area in which the material constituting the first filter layer is dispersed and the material constituting the second filter layer is dispersed. The light guide includes a layer that is provided so as not to overlap the second distributed arrangement region to be arranged.

  By using such a light guide, the first display area or the second display area can be visually recognized even though the first display area and the second display area overlap. Further, by using the material constituting the first filter layer and the material constituting the second filter layer, the overlap display area, the first display area excluding the overlap display area, or the overlap display area, and the overlap display area The color tone of the second display area except for can be made the same level.

  According to the present invention, there is provided a member for a push button switch comprising the light guide according to any one of claims 1 to 6.

  By using such a push button switch member, the push button portion can be easily viewed with high luminance. Further, when a display layer is provided in the opening, only the necessary display can be displayed by illuminating the push button portion with high luminance and changing the illumination color.

  ADVANTAGE OF THE INVENTION According to this invention, the member for pushbutton switches using the light guide which uses the light guide for the display part and / or input part to be more highly visible and is easy to visually recognize can be provided.

It is a top view of the light guide which concerns on the 1st Embodiment of this invention. It is AA sectional view taken on the line of the light guide shown in FIG. It is sectional drawing which cut | disconnects and shows the light guide which concerns on the 2nd Embodiment of this invention by the line similar to the AA line of FIG. It is sectional drawing which cut | disconnects and shows the light guide which concerns on the 3rd Embodiment of this invention with the same line as the AA of FIG. It is an enlarged plan view which expands and shows the display layer provided in the opening part of the light guide shown in FIG. It is a top view which shows the pattern displayed when the display of the display layer of FIG. 5 is switched. FIG. 7 is a plan view for explaining the relationship between the position of the first display area in FIG. 5 and the position of the second display area in FIG. 6. It is an expanded sectional view which expands and shows the display layer shown in FIG. It is a top view of the display layer in the light guide which has another embodiment. It is an expanded sectional view which expands and shows the display layer cut | disconnected by the same line as the AA of FIG. It is an external view of the member for pushbutton switches which concerns on this invention. It is sectional drawing at the time of cut | disconnecting the member for pushbutton switches in the DD line | wire of FIG. It is sectional drawing cut | disconnected and shown by the same line as the AA of FIG. 1 in the light guide which concerns on the 4th Embodiment of this invention. It is an expanded sectional view which expands and shows the structure of the area | region C shown by the dashed-dotted line of FIG. It is a flowchart which shows the manufacturing process of the light guide which concerns on the 4th Embodiment of this invention. It is a figure which shows a part of manufacturing process of the light guide which concerns on the 4th Embodiment of this invention in steps.

  Preferred embodiments of a light guide and a push button switch member using the light guide according to the present invention will be described below in detail with reference to the drawings. However, the present invention is not limited to the preferred embodiments described below.

(First embodiment)
FIG. 1 is a plan view of a light guide 100 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the light guide 100 shown in FIG.

  As shown in FIG. 1 and FIG. 2, the light guide 100 has an opening 5 and covers a first light reflecting layer 10, a light transmissive light guide plate 12, and a first light reflecting layer 10. And a second light reflecting layer 20 that is disposed on the opposite side of the light-transmitting light guide plate 12 and is laminated. Since the light source fixed to the circuit board (hereinafter referred to as “substrate”, not shown) on the back side of the light guide 100 is disposed close to the side surface of the light guide 100, the light from the light source is Incident from the side surface of the light guide 100. In this embodiment, the light source is an LED. As the LED, for example, a white LED, a blue LED, a red LED, a yellow LED, an orange LED, and a green LED may be used. Also, a plurality of LEDs may be used. For example, white is generated from LEDs of three colors of red, green, and blue (so-called RGB), or a plurality of LEDs are turned on / off and introduced into the light guide. The light may be switched.

  The translucent light guide plate 12 that is a main component of the light guide 100 is a substantially planar translucent member that emits light from the light source through the opening 5. A material having a refractive index of 1.4 with respect to a refractive index of 1.0 of the air layer, for example, polyethylene terephthalate resin (PET) can be suitably used. For this reason, the incident light can travel inside the translucent light guide plate 12 while being repeatedly reflected on the front side surface and the back side surface of the translucent light guide plate 12, so that light energy can be used without waste. , The brightness can be further increased. However, the translucent light guide plate 12 is made of a resin other than polyethylene terephthalate resin (PET), such as polycarbonate resin (PC), polypropylene resin (PP), polymethyl methacrylate resin (PMMA), benzyl methacrylate resin, MS resin, acrylic resin. It may be made of a resin or an optically transparent resin such as cycloolefin polymer (COP).

  Moreover, the manufacturing method in particular of the translucent light-guide plate 12 is not restrict | limited, A well-known technique can be used. For example, the translucent light guide plate 12 can be manufactured by cast molding using a raw material such as a transparent resin, extrusion molding, injection molding, press molding, or the like.

  Moreover, it is preferable that the light transmissive light guide plate 12 is provided with the light diffusion portion 13 at a position facing the opening portion 5 of the first light reflection layer 10 on at least one of the front side and the back side. In this embodiment, as shown in FIG. 2, a light diffusion portion 13 is formed at a position on the back side of the translucent light guide plate 12 and facing the opening 5. The light diffusing unit 13 is a configuration for efficiently emitting light toward the surface on the front side of the translucent light guide plate 12. In this embodiment, as shown in FIG. 2, the light diffusion part 13 is formed from a plurality of cone-shaped recesses. The shape of the concavo-convex structure constituting the light diffusion portion 13 is not particularly limited, and may be any shape such as a round dot, a square dot, or a chain dot. Further, it may be formed in a stripe shape instead of a dot. As a method of forming the light diffusion portion 13, a known method can be used. For example, a method of forming a convex body on the front or back surface of the light transmissive light guide plate 12 in advance, A method of printing a convex body can be employed.

  The first light reflection layer 10 and the second light reflection layer 20 are layers that reflect light to be emitted from the light transmissive light guide plate 12 to the inside of the light transmissive light guide plate 12. As a method for forming the first light reflection layer 10 and the second light reflection layer 20, for example, high concealment and high whiteness are respectively provided on desired portions of the back side and front side of the translucent light guide plate 12. A white layer in which powders such as titanium dioxide and aluminum that are pigments are dispersed is formed by painting, or a metal thin film layer is formed by plating or vapor-depositing a metal such as aluminum, chromium, or silver, A low refractive index layer made of a material having a lower refractive index than that of the translucent light guide plate 12 may be formed. Among these, it is preferable to form a mirror and a metal thin film layer capable of forming a mirror. A plurality of first light reflection layers 10 and second light reflection layers 20 may be laminated. For this reason, when the light from the light source is guided while being reflected in the translucent light guide plate 12, the light to be emitted to the outside by the first light reflecting layer 10 and the second light reflecting layer 20 is directed to the inside. It has a function of reflecting and returning it into the light-transmissive light guide plate 12 again. Therefore, the ratio of light leakage from locations other than the opening 5 is extremely low, and light is easily emitted only from the opening 5.

  In the light guide 100 having such a configuration, the light incident from the light source into the translucent light guide plate 12 travels while being reflected by the first light reflecting layer 10 and the second light reflecting layer 20, The light is emitted from the opening 5 to the outside. For this reason, the light from the light source can be emitted through the opening 5 without being lost unnecessarily.

(Second embodiment)
Next, a light guide 200 according to a second embodiment of the present invention will be described.

  The light guide 200 according to the second embodiment has a common part with the light guide 100 according to the first embodiment described above. In the following description of the second and subsequent embodiments, the common parts are denoted by the same reference numerals as those in the first embodiment, and the parts having the same structure are duplicated. Description is omitted.

  FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1 in the light guide 200 according to the second embodiment of the present invention.

  In the second embodiment, as shown in FIG. 3, unlike the first embodiment, in the light guide 200, the outer surface of the first light reflecting layer 10 and the outer side of the second light reflecting layer 20 are further provided. On the surface, a light shielding layer 15 and a light shielding layer 16 are provided, respectively. A light diffusing portion 13 is formed at a position corresponding to the opening 5 on the front side surface of the translucent light guide plate 12. The light shielding layers 15 and 16 shield the light incident on the light transmissive light guide plate 12 from a light source fixed on the substrate so as not to leak from a region other than the opening 5 or enter the light transmissive light guide plate 12. This is a reflective layer. The light shielding layers 15 and 16 can be suitably formed using non-translucent ink. However, the present invention is not limited to this, and other non-light-transmitting materials may be used. Here, in order to achieve non-translucency, the total light transmittance is preferably 1% or less. Specifically, the light shielding layers 15 and 16 are formed, for example, by coating with a black or white ink to a thickness of about 1 to 30 μm. The black light shielding layers 15 and 16 can absorb a small amount of light emitted from the first light reflecting layer 10 and the second light reflecting layer 20. For this reason, the brightness of the opening 5 is visually recognized relatively high with respect to the surroundings. On the other hand, the white light shielding layers 15 and 16 can reflect a small amount of light emitted from the first light reflection layer 10 and the second light reflection layer 20 to the inside of the translucent light guide plate 12. For this reason, the quantity of light emitted from the opening 5 increases, and the brightness of the opening 5 increases.

(Third embodiment)
Next, a light guide 300 according to a third embodiment of the present invention will be described.

  FIG. 4 is a cross-sectional view showing a light guide 300 according to the third embodiment of the present invention cut along a line similar to the AA line in FIG. FIG. 5 is an enlarged plan view showing the display layer 30 provided in the opening 5 of the light guide 300 shown in FIG. 4 in an enlarged manner. FIG. 6 is a plan view showing a pattern displayed when the display of the display layer 30 in FIG. 5 is switched.

  In the third embodiment, as shown in FIG. 4, unlike the second embodiment, in the light guide 300, a display layer 30 is further provided in the opening 5.

  When the display layer 30 is illuminated by the light of a first light source (described later) that has passed through the opening 5 from the back side (the back side of the paper in FIG. 1), the first display region 40 (the inner oblique line portion of the circle in FIG. 5). ) Only through the light. For this reason, the user can visually recognize only the first display area 40.

  On the other hand, when the display layer 30 is illuminated from the back side by light from a second light source described later that has passed through the opening 5, the second display area 50 (FIG. 6) is used instead of the first display area 40. Light is transmitted only from the inside diagonal line of the triangle. For this reason, the user can visually recognize only the second display area 50. When both the first light source and the second light source are turned off, the user cannot visually recognize both the first display area 10 and the second display area 20.

  FIG. 7 is a plan view for explaining the relationship between the position of the first display area 40 in FIG. 5 and the position of the second display area 50 in FIG.

  Since the center of the first display area 40 and the center of the second display area 50 are substantially the same, the first display area 40 and the second display area 50 partially overlap. The area where the first display area 40 and the second display area 50 overlap is hereinafter referred to as an overlapping display area 60.

  FIG. 8 is an enlarged cross-sectional view showing the display layer 30 shown in FIG. 4 in an enlarged manner.

  The display layer 30 includes a first filter layer 71, a second filter layer 72, and a filter layer 73 (hereinafter referred to as filter layers 71, 72, and 73). In the present embodiment, the filter layers 71, 72, 73 are print layers formed with colored ink.

  In the present embodiment, the filter layer 71 is provided in an area overlapping the first display area 40 excluding the overlapping display area 60. The filter layer 71 is a layer that transmits only light in a predetermined wavelength region with a transmittance of 80% or more, whereas the transmittance of light in other wavelength regions is 20% or less. For example, the filter layer 71 transmits visible light having a wavelength of 600 nm or more to a transmittance of 80% or more, and absorbs visible light having a wavelength of 600 nm or less. Therefore, the transmittance of visible light having a wavelength of 600 nm or less is 20 % Or less. For example, a red ink layer can be suitably used as the filter layer 71.

  When the region where the filter layer 71 is formed is irradiated with light including visible light having a wavelength of 600 nm or more (that is, red light), the filter layer 71 transmits only red light. Therefore, the user can visually recognize the region of the filter layer 71 that shines red on the surface of the display layer 30.

  On the other hand, when the region where the filter layer 71 is formed is irradiated with light including only visible light having a wavelength of 600 nm or less (for example, blue light emitted from the LED) through the opening 5 of the light guide 300, the user A region where the filter layer 71 is provided on the surface of the display layer 30 cannot be visually recognized. This is because the filter layer 71 absorbs visible light having a wavelength of 600 nm or less.

  The filter layer 72 is provided in a portion of the receiving layer 35 that overlaps the second display area 50 excluding the overlapping display area 60. The filter layer 72 is a layer that transmits light in a wavelength region that can be transmitted by the filter layer 71 only at a transmittance of 20% or less, while transmitting light in a wavelength region that cannot be transmitted by the filter layer 71 at 80% or more. For example, the filter layer 72 is a layer that transmits visible light having a wavelength of 500 nm or less while absorbing visible light having a wavelength of 500 nm or more. As such a filter layer 72, for example, a blue ink layer can be suitably employed.

  When the region where the filter layer 72 is formed is irradiated with light including visible light having a wavelength of 500 nm or less (that is, blue light), the filter layer 72 transmits only blue light. Therefore, the user can visually recognize the region of the filter layer 72 that shines in blue on the surface of the display layer 30.

  On the other hand, when the region where the filter layer 72 is formed is irradiated with light including only visible light having a wavelength of 500 nm or more through the opening 5 of the light guide 300 (for example, red light emitted from the LED), the user The region where the filter layer 72 is provided on the surface of the display layer 30 cannot be visually recognized. This is because the filter layer 72 absorbs visible light having a wavelength of 500 nm or more.

  The filter layer 73 is provided in an area overlapping the overlap display area 60. The filter layer 73 is a layer that can transmit light in the wavelength region that can be transmitted by the filter layer 71 at a transmittance of 80% or more, and can also transmit light in the wavelength region that can be transmitted by the filter layer 72 at a transmittance of 80% or more. As such a filter layer 73, for example, a thin yellow ink layer can be employed.

  For example, assuming that the filter layer 73 is a layer that allows light having a wavelength of 430 nm to 780 nm to pass through, when blue light having a wavelength of 430 nm to 480 nm is incident on the filter 73, the filter layer 73 emits blue light. . Therefore, the user can visually recognize the region of the filter layer 73 that shines blue on the surface of the display layer 30.

  On the other hand, when the filter layer 73 receives red light having a wavelength of 650 nm to 780 nm, the filter layer 73 emits red light. Therefore, the user can visually recognize the region of the filter layer 73 that shines red on the surface of the display layer 30.

  The first light source is a light source that mainly transmits light in a wavelength region that can be transmitted through the filter layer 71 through the opening 5 of the light guide 300 as light in the first predetermined wavelength band and is absorbed by the filter layer 72. is there. In the present embodiment, since the filter layer 71 is a layer that transmits red light, the first light source is a light source that emits light in a wavelength region of about 600 nm to 780 nm. The first light source irradiates at least the first display region 40 and the overlapping display region 60 from the back side of the display layer 30 through the opening 5 of the light guide 300, but the first display region 40 and the overlapping display region 60. In addition, the second display area 50 may be irradiated.

  On the other hand, the second light source mainly transmits light in a wavelength region that can be transmitted through the filter layer 72 through the opening 5 of the light guide 300 as light in the second predetermined wavelength band and is absorbed by the filter layer 71. Light source. In this embodiment, since the filter layer 72 is a layer that transmits blue light, the second light source is a light source that emits light in a wavelength region of about 400 nm to 500 nm. The second light source irradiates at least the second display region 50 and the overlapping display region 60 from the back side of the display layer 30 through the opening 5 of the light guide 300, but the second display region 50 and the overlapping display region 60. In addition, the first display area 40 may also be irradiated.

  As the first light source and the second light source, any light source that mainly emits light in a desired wavelength region can be used, but an LED is particularly preferable. This is because the light emitted from the LED hardly contains light in an undesired wavelength region and has a narrower wavelength distribution range of the emitted light than a light bulb or the like. The wavelength region of light emitted from the LED is determined by the band gap of the material constituting the LED.

  In the above-described third embodiment of the present invention, the first light source illuminates the first display area 40 and the second display area 50 from the back side of the display layer 30 through the opening 5 of the light guide 300. Then, only the first display area 40 is visually recognized on the surface of the display layer 30. This is because the filter layer 72 absorbs the light having the wavelength emitted from the first light source, and thus the light emitted from the first light source cannot pass through the second display region 50 except for the overlapping display region 60. . When the first light source that emits red light is turned on, the first display area 40 including the overlapping display area 60 appears red to the user.

  On the other hand, when the second light source illuminates the first display area 40 and the second display area 50 from the back side of the display layer 30 through the opening 5 of the light guide 300, only the second display area 50 is Visible on the surface of the display layer 30. When the second light source emitting blue light is turned on, the second display area 50 including the overlapping display area 60 appears blue. Therefore, in the first embodiment, although the first display area 40 and the second display area 50 partially overlap, the first display area 40 including the overlapping display area 60, Alternatively, the second display area 50 including the overlapping display area 60 can be illuminated.

  Next, light guides 300 according to embodiments other than those described above will be described with reference to the drawings.

  FIG. 9 is a plan view of the display layer 80 in the light guide 300 having another embodiment. FIG. 10 is an enlarged cross-sectional view showing the display layer 80 cut along a line similar to the line AA in FIG.

  In this embodiment, the display layer 80 includes a filter layer 71 and a filter layer 72. The filter layer 71 is provided in an area overlapping the first display area 40 excluding the overlapping display area 60. The filter layer 72 is provided in an area overlapping the second display area 50 excluding the overlapping display area 60.

  In this embodiment, the overlapping display area 60 is arranged so that the minute dots in which the colored ink constituting the filter layer 71 is dispersed and the minute dots in which the colored ink constituting the filter layer 72 are dispersed do not overlap each other. Configured. The minute dots constituting the overlapping display area 60 are sufficiently smaller than the first display area 40 and the second display area 50. For example, when the vertical and horizontal dimensions of the first display area 40 and the second display area 50 are several millimeters, the overlapping display area 60 is configured with minute dots having a diameter of about 0.05 to 0.3 mm. It is preferable to do. The fine dots may be polygons instead of circles. Further, adjacent minute dots may partially overlap or be separated.

  By forming such an overlapping display area 60, the first display area 40 and the second display area 50 partially overlap, and there is no need to provide another ink layer in the overlapping display area 60. The first display area 40 or the second display area 50 each including the overlapping display area 60 can be visually recognized by the user. This is because the dots arranged in the overlapping display area 60 are minute and light diffuses around the dots, so that the user visually recognizes that the entire overlapping display area 60 is shining in a predetermined color. That is, for the user, even when the first light source illuminates the overlapping display area 60 through the opening 5 of the light guide 300, and when the second light source illuminates the overlapping display area 60, the overlapping display is performed. This is because the entire region 60 appears to emit light.

(Fourth embodiment)
Next, a light guide 400 according to a fourth embodiment of the present invention will be described.

  FIG. 13: is sectional drawing cut | disconnected and shown by the same line as the AA line of FIG. 1 in the light guide 400 which concerns on the 4th Embodiment of this invention. FIG. 14 is an enlarged cross-sectional view showing an enlarged configuration of a region C indicated by a one-dot chain line in FIG.

  In the fourth embodiment, as shown in FIG. 13 and FIG. 14, unlike the first embodiment, in the light guide 400, the surface of the translucent light guide plate 12, the opening 5 and the light. The structure which integrates the spreading | diffusion part 13 is formed. The first light reflecting layer 10 is provided with a concavo-convex portion having a concave portion reaching the translucent light guide plate 12. The opening 5 includes the uneven portion. The surface of the concave portion formed inside the light transmissive light guide plate 12 serves as a light diffusing portion 13 when light that guides the light transmissive light guide plate 12 is emitted from the opening 5.

  Next, a method for manufacturing the light guide 400 according to the fourth embodiment of the present invention will be described.

  FIG. 15 is a flowchart showing manufacturing steps of the light guide 400 according to the fourth embodiment of the present invention. FIG. 16 is a diagram showing a part of the manufacturing process of the light guide 400 according to the fourth embodiment of the present invention step by step.

  First, the 1st light reflection layer 10 and the 2nd light reflection layer 20 are each formed in both surfaces of the translucent light-guide plate 12 (step S101). In this embodiment, as shown in FIG. 16A, for example, powders such as titanium dioxide and aluminum, which are pigments having high concealment and high whiteness, are applied to the back side and the front side of the light-transmitting light guide plate 12, respectively. The dispersed white layer can be formed by painting or the like, or a metal thin film layer can be formed by plating or vapor-depositing a metal such as aluminum, chromium or silver. Among these, it is preferable to form a mirror and a metal thin film layer capable of forming a mirror.

  Next, as shown in FIG. 16B, the molding obtained in the above process is placed in a molding die (step S102).

  Subsequently, as shown in FIG. 16C, the molding die 80 is closed to perform molding (step S103). In this embodiment, the mold 81 and the mold are arranged after the mold 81 is disposed between one mold 81 constituting the molding mold 80 and the other mold 82 having the convex portion. 82 is closed and molding is performed. As a result, a part of the first light reflecting layer 10 is broken by the convex portion of the mold 82, and the opening 5 including a plurality of concave and convex portions is formed.

  Finally, as shown in FIG. 16D, the molding die 80 is opened and the light guide 400 is taken out. Thus, since the opening part 5 and the light-diffusion part 13 can be formed at once, cost reduction can be implement | achieved by labor saving of a manufacturing process.

(Fifth embodiment)
Next, a preferred embodiment of the push button switch member 500 according to the present invention will be described with reference to the drawings. In addition, each embodiment of the member 500 for pushbutton switches demonstrated below includes the light guide 100 which has the structure similar to the above as a part of the structural member. Note that light guides 200, 300, and 400 may be included instead of the light guide 100.

  FIG. 11 is an external view of a pushbutton switch member 500 according to the present invention. FIG. 12 is a cross-sectional view of the pushbutton switch member 500 taken along line DD in FIG. In the cross-sectional view shown in FIG. 12, the scale in the thickness direction is changed in order to make the drawing easier to see.

  The push button switch member 500 is used in an operation unit of an electronic device. A plurality of light sources (not shown) are arranged inside the electronic device, that is, on the back side as viewed from the usage surface. The plurality of light sources are turned on or off as necessary.

  As shown in FIG. 12, the pushbutton switch member 500 is composed of a key top sheet 8 and a light guide 100 (200, 300 or 400). A plurality of key tops (one form 3 of a display unit or an input unit) are formed on the key top sheet 8 at a position facing the opening 5 of the light guide 100 (200, 300, or 400). A member made of polycarbonate resin is preferably 8. A decorative layer having a pattern such as letters, numbers, or a pattern may be formed on the entire surface or a part of the bottom surface of the key top 3. The method for forming the layer is not particularly limited, and can be formed by a known method using an ink or a paint, etc. In order to improve the fixability, adhesion or color development of the ink or paint, etc. It is preferable to modify the surface or bottom surface of the key top 3 in advance by performing various known surface treatments, etc. By forming a decorative layer, the key top sheet is formed. In addition, when a decorative layer is formed on the surface of the key top 3, it is preferable to form a protective layer made of a transparent resin on the outer surface of the decorative layer. If formed, the decorative layer can be effectively protected from trauma.

  When light is incident on the light guide 100 from the light source, the light is emitted from the front surface of the key top 3 through the opening 5 of the light guide 100, 200 or 400 and is visually recognized by the user. When the light guide 300 provided with the display layer 30 is employed, the function display of the key top 3 can be switched by switching the illumination of a plurality of light sources.

  The preferred embodiments of the light guide 100, 200, 300, 400 and the push button switch member 500 using the light guide 100 according to the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The present invention can be implemented in variously modified forms.

  For example, in each embodiment, the shape, size, arrangement, or number of the openings 5 can be appropriately changed according to the required design of the key top 3.

  Further, when the thickness of the translucent light guide plate 12 in the Z-axis direction is thinner than the height of the light source in the Z-axis direction, the translucent light guide plate 12 is contacted from the back surface side of the light source. You may have the light-receiving part which inclines so that it may contact in the edge part by the side of the light source of the translucent light-guide plate 12. FIG. The translucent light guide plate 12 having such a light receiving part can collect light emitted from the light source side inside the translucent light guide plate 12.

  In the third embodiment, the filter layer 71 is a red ink layer, the filter layer 72 is a blue ink layer, and the filter layer 73 is a light yellow ink layer. However, the present invention is not limited to such an ink layer. However, it is desirable that the color of the filter layer 71 and the color of the filter layer 72 have a complementary relationship. Since the wavelength regions of light emitted from the first light source and the second light source are greatly different, light close to the maximum wavelength or light close to the minimum wavelength included in the light emitted from the light source for causing one filter layer to emit light This is because transmission from the filter layer can be reduced.

  In the third embodiment, the overlapping display area 60 is an area in which two types of dots are arranged, but is not limited to such a form. For example, a thin line shape may be used. In the third embodiment, the dot arrangement is regular but may be irregular. The shape of the dot may be round, polygonal, or any other shape.

  The present invention can be used, for example, in industries that manufacture or use portable electronic terminals equipped with a pushbutton switch member.

3. Key top (display unit, input unit)
8 ... key top sheet 5 ... opening 10 ... first light reflection layer 12 ... translucent light guide plate 13 ... light diffusion parts 15, 16 ... light shielding layer 20 ... second light reflection layers 30, 80 ... display layer 40 ... first 1 display area 50 ... second display area 60 ... overlapping display area 71 ... filter layer (first filter layer)
72 ... Filter layer (second filter layer)
73 ... Filter layer (third filter layer)
100, 200, 300, 400 ... Light guide 500 ... Push button switch member

Claims (8)

A light guide that is placed opposite to the back side of the display unit or input unit to be illuminated, receives light from a plurality of light sources, guides it to the inside, and emits light toward the display unit or the input unit to illuminate it. There,
For emitting light that has passed through the interior of the translucent light guide plate to a position on the front side of the translucent light guide plate that is the main part of the light guide and facing the display unit or the input unit. Covering the first light reflecting layer covering the region other than the opening and the back side surface of the translucent light guide plate, reducing the emission of light that has passed through the translucent light guide plate; And a second light reflecting layer for reflecting the light.   The translucent light guide plate diffuses light that has passed through the translucent light guide plate to a position facing the display unit or the input unit on at least one of the front side and the back side. The light guide according to claim 1, further comprising a light diffusing portion for emitting light from the opening.   A light shielding layer for further reducing light emission from the outer surface is further provided on the outer surface of the first light reflecting layer and / or the outer surface of the second light reflecting layer. The light guide according to claim 1, wherein the light guide is a light guide.   The light guide according to any one of claims 1 to 3, wherein the opening is provided with a filter layer for shielding light of a specific color. The opening is provided with a display layer having an overlapping display region in which at least the first display region and the second display region partially overlap,
The first display area excluding the overlapping display area has a first filter layer,
The second display area excluding the overlapping display area has a second filter layer,
The first filter layer transmits light of the first predetermined wavelength band more easily than the second filter layer, and transmits light of the second predetermined wavelength band than the second filter layer. Layer that is hard to do,
The second filter layer is easier to transmit light in the second predetermined wavelength band than the first filter layer, and is less likely to transmit light in the first predetermined wavelength band than the first filter layer. Layer,
4. The light guide according to claim 1, wherein the overlapping display region transmits both the light of the first predetermined wavelength band and the light of the second predetermined wavelength band. 5. .   55. The light guide according to claim 54, wherein the overlapping display region includes a third filter layer that transmits both the light of the first predetermined wavelength band and the light of the second predetermined wavelength band. .   The overlapping display region includes a first dispersion placement region in which the material constituting the first filter layer is dispersedly arranged, and a second dispersion placement region in which the material constituting the second filter layer is dispersedly arranged. The light guide according to claim 54, further comprising a layer provided so as not to overlap each other.   A member for a push button switch, comprising the light guide according to claim 1.

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