JP2012043545A - Light guide structure of light guide layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide structure of a light guide layer that suppresses a leak of a light beam from an edge nearby a boundary between a peripheral surface of a pressing element and the light guide layer, and prevents an illumination property of an operation key and designability of an operation input layer from becoming worse as the pressing element serves as a bright point.SOLUTION: The light guide structure includes a circuit board 20 which has metal domes 22 arrayed on a surface, and an operation input layer 30 which has operation keys 31 opposed to the metal domes 22, and has the light guide layer 40, guiding a light beam from an LED 21, interposed between the circuit board 20 and the operation input layer 30 to irradiate the operation keys 31 with the light beam guided to the light guide layer 40. Substantially columnar pressing elements 50 which are pressed against the metal domes 22 to turn on the metal domes are integrally formed on a reverse surface of the light guide layer 40, and at least opposite surfaces 54 of peripheral surfaces 51 of the pressing elements 50 which are positioned on opposite sides from the LED 21 are inclined at an angle of inclination of ≤45°.

Description

  The present invention relates to a light guide layer light guide structure used in portable devices, information communication devices, and the like.

  The light guide structure of the conventional light guide layer is not shown, but includes a circuit board in which a plurality of metal domes are arranged, and an operation input layer in which operation keys are opposed to the plurality of metal domes on the circuit board. A light guide layer for guiding light from the LED is interposed between the substrate and the operation input layer, and the light guided to the light guide layer is irradiated to a plurality of operation keys of the operation input layer. It functions (see Patent Document 1). The light guide layer is formed with a cylindrical pressing element, or a pressing layer having a cylindrical pressing element is laminated, and the pressing element is brought into pressure contact with the metal dome of the circuit board to be turned on.

  In the above configuration, when the LED emits light, the light beam is guided while being reflected from the LED into the light guide layer, irradiated from the light guide layer to a plurality of operation keys of the operation input layer, and each operation key is illuminated. The

JP 2010-62086 A

  The light guide structure of the light guide layer in the past is configured as described above, and the presser that turns on the metal dome of the circuit board is simply a cylinder, so the vertical peripheral surface of the presser and the boundary with the light guide layer The light beam guided from the edge of the light leaks and emits light, which may hinder the light guide. In particular, there is a high risk of light leakage from the opposite surface located on the opposite side of the LED or the base edge of the peripheral surface of the presser. As a result, there is a problem that the pressing element, particularly the peripheral surface thereof, becomes a bright spot and shines abnormally, and the illumination of the operation key is deteriorated or the design of the operation input layer is impaired.

  The present invention has been made in view of the above, and suppresses the leakage of light from the peripheral surface of the presser and the edge near the boundary with the light guide layer, and the presser becomes a luminescent spot to illuminate and operate the operation keys. An object of the present invention is to provide a light guide layer light guide structure capable of preventing deterioration in design of an input layer.

In order to solve the above problems, the present invention includes a circuit board having a contact switch on the surface, and an operation input layer that opposes an operation key to the contact switch of the circuit board. In between, a flexible light guide layer for guiding the light from the light source is interposed, and the light guided to the light guide layer is irradiated to at least the operation key of the operation input layer,
A substantially columnar pressing element is integrally formed on either one of the front and back surfaces of the light guide layer so as to be pressed on the contact switch of the opposite circuit board to be turned on, and at least of the peripheral surface of the pressing element opposite to the light source. The opposite surface located on the side is inclined so as to gradually spread at an inclination angle of 45 ° or less.

A presser is integrally formed on the back surface of the light guide layer, and a light emitting pattern located above the presser is formed on the surface of the light guide layer, and the light beam guided by the light emitting pattern is transmitted to the operation input layer. At least the operation keys can be irradiated.
Further, the pressing element can be formed in a substantially truncated cone shape.
Moreover, it is preferable to round and form the boundary part of the press-contact surface which press-contacts to the contact switch of a presser, and the inclined surrounding surface.

  Here, the contact switch, the operation key, the light source, and the presser in the claims do not particularly have to be singular. The contact switch is preferably a metal dome type that can be warped from the viewpoint of extending the life cycle. The light source can be appropriately arranged at the front end portion, the end portion, the one side portion, the other side portion, or the like of the peripheral surface of the light guide layer. Further, an air layer, an adhesive layer, or the like may be interposed between the operation input layer and the light guide layer. It is preferable to impart light transparency to at least the operation keys of the operation input layer.

According to the present invention, when the light source emits light, the light beam is guided while being reflected from the light source into the light guide layer, irradiated from the light guide layer to the operation key of the operation input layer, and at least a part of the operation key is irradiated. Illuminated.
At this time, the light beam also enters the presser integral with the light guide layer, but at least the opposite surface of the peripheral surface of the presser that is likely to leak light is not vertical, but at an inclination angle of 45 ° or less. Since it is gradually inclined, there is little light emission due to leakage from the inclined peripheral surface of the presser or the edge near the boundary with the light guide layer.

  According to the present invention, light is prevented from leaking from the peripheral surface of the presser or the edge near the boundary with the light guide layer, and the presser becomes a luminescent spot, and the illumination of the operation key and the design of the operation input layer There is an effect that it is possible to prevent the deterioration.

  According to the second aspect of the present invention, since the presser is not formed in a complicated shape having a plurality of irregularities or notches, but is formed in a truncated cone shape, for example, both ends of the light guide layer, front and rear, left and right Even if a plurality of light sources are installed and light is guided from a plurality of different directions, the light can be prevented from leaking from the peripheral surface of the presser or the edge near the boundary with the light guide layer. Simplification and ease of manufacture can be expected.

  According to the invention described in claim 3, the boundary between the press contact surface and the peripheral surface of the presser is not angular, and it is possible to prevent a change in the reflection angle of the light beam. It is possible to suppress leakage and excessive increase in luminance of the presser.

It is a disassembled perspective view which shows typically the mobile telephone in embodiment of the light guide structure of the light guide layer which concerns on this invention. It is a fragmentary sectional view showing typically an embodiment of a light guide structure of a light guide layer concerning the present invention. It is an expansion explanatory view showing typically a presser in an embodiment of a light guide structure of a light guide layer concerning the present invention. It is a fragmentary sectional view showing typically a 2nd embodiment of a light guide structure of a light guide layer concerning the present invention. It is a partial section explanatory view showing typically the example and comparative example of the light guide structure of the light guide layer concerning the present invention. It is a fragmentary sectional view showing typically the comparative example of the light guide structure of the light guide layer concerning the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A light guide structure of a light guide layer in the present embodiment includes a circuit board 20 built in a mobile phone 1 as shown in FIGS. A light guide layer 40 for guiding a light beam from the LED 21 between the circuit board 20 and the operation input layer 30. The operation key 31 of the operation input layer 30 is irradiated with the guided light beam, and the light guide layer 40 is formed with a presser 50 that turns on the metal dome 22 of the circuit board 20. The peripheral surface 51 is inclined at a predetermined inclination angle.

  As shown in FIG. 1, the mobile phone 1 includes a first housing 3 having a mouthpiece 2 and a second housing 9 that is pivotally supported at the tip of the first housing 3 so as to be foldable. The earpiece 10 is provided at the tip of the second housing 9. The first housing 3 includes a front cover 4 and a back cover 5 that sandwich and sandwich the circuit board 20, the operation input layer 30, and the light guide layer 40, and between the front cover 4 and the back cover 5. Includes a small microphone (not shown). A storage hole 7 for storing the thin battery 6 is formed in the back surface of the back cover 5 so that the battery cover 8 for the battery 6 is detachably attached to the storage hole 7 from the outside.

  The second housing 9 includes a front cover 13 and a rear cover 14 that sandwich the display device 12 that is electrically connected to the circuit board 20 via the flexible board 11. Between the front cover 13 and the back cover 14, a small speaker 15 and a camera (not shown) are built. An infrared input / output device 16 is attached to the end of the display device 12.

  As shown in FIG. 1 and FIG. 2, the circuit board 20 has a plurality of metal domes 22 arranged in the XY direction together with a wiring pattern on the surface, and the plurality of metal domes 22 function as contact switches. A pair of LEDs 21 are disposed at the end of the surface of the circuit board 20 with an interval, and the pair of LEDs 21 are adjacent to the opposing portions of the peripheral surface of the light guide layer 40 with a slight interval, White or blue light rays indicated by arrows in FIG. 2 are irradiated.

  Each metal dome 22 is formed in a hollow, substantially hemispherical shell shape that can be elastically deformed using a thin SUS plate or the like from the viewpoint of obtaining a good click feeling. The metal dome 22 is deformed by being pressed from above, and the circuit of the circuit board 20 is turned on. The pressure is released, and the circuit is turned off by returning to the original form.

  As shown in FIG. 1 and FIG. 2, the operation input layer 30 is made of a thin sheet having a flexible elongated flat rectangular shape, etc., and is flattened with a double-sided adhesive tape or adhesive on the surface peripheral portion of the light guide layer 40. It is adhered and is almost flush with the front cover 4 of the mobile phone 1. The sheet of the operation input layer 30 is not particularly limited, and examples thereof include a sheet made of polycarbonate (PC) or polyethylene terephthalate (PET) that is excellent in dimensional stability and strength.

  On the flat surface of the operation input layer 30, a plurality of operation keys 31 respectively positioned directly above the plurality of metal domes 22 of the circuit board 20 are integrally arranged at a predetermined interval, and each operation key 31 has a planar rectangular shape. After the section is formed, an operation pattern (letters, numbers, symbols, etc.) is printed on the surface. Each operation key 31 is provided with light transmissivity for illumination at least at the periphery.

  As shown in the figure, the light guide layer 40 is made of a thin flat rectangular sheet or film having flexibility, and is laminated on the circuit board 20 and adhered to the peripheral edge of the back surface of the operation input layer 30. The light guide layer 40 is not particularly limited. For example, the light guide layer 40 is made of a transparent silicone rubber or polyurethane having excellent light guiding properties, and has a thickness of about 0.1 to 0.2 mm, preferably about 0.125 mm. It is formed into a long and thin flat rectangle with a film.

  On the flat surface of the light guide layer 40, light emission patterns 41 respectively positioned immediately below the plurality of operation keys 31 of the operation input layer 30 are dot-printed with white ink or the like. Each light emitting pattern 41 functions to irradiate and illuminate the operation key 31 of the operation input layer 30 with the light beam guided as the light emitting pattern.

  As shown in FIGS. 2 and 3, the pressing members 50 are integrally arrayed and formed on the flat back surface of the light guide layer 40 at a predetermined interval, and respectively face the plurality of metal domes 22 of the circuit board 20 from above. At the same time, they are positioned below the plurality of light emitting patterns 41, and are pressed against the metal dome 22 to be deformed, thereby turning on the circuit of the circuit board 20.

  Each pressing element 50 is formed into a low-profile transparent frustoconical shape having a height of about 0.2 mm, for example, and all peripheral surfaces 51 are 45 ° or less, preferably from the viewpoint of reducing material costs and preventing light leakage. It inclines so that it may spread gradually at an inclination angle of 5 ° to 45 °, more preferably 10 ° to 45 °. The boundary portion 53 between the flat pressure contact surface 52 that presses against the curved surface of the metal dome 22 of the presser 50 and the inclined peripheral surface 51 is smoothly rounded and rounded to prevent light leakage. .

  In the above configuration, when a predetermined operation key 31 of the operation input layer 30 is pressed, the corresponding pressure element 50 is pressed against the metal dome 22 of the circuit board 20 while the light guide layer 40 is bent, and the corresponding metal dome is pressed. 22 is crushed and deformed, the circuit of the circuit board 20 is turned on, and predetermined functions of the cellular phone 1 (for example, telephone transmission function, new mail creation and transmission function, etc.) are executed.

  Next, when a predetermined operation key 31 of the operation input layer 30 is pressed and the pair of LEDs 21 emits light, light rays are guided from each LED 21 while being repeatedly totally reflected in the XY directions in the light guide layer 40. A plurality of operation keys 31 are diffused and irradiated from the light emission pattern 41 on the surface of the light guide layer 40, and at least the peripheral edge of each operation key 31 is illuminated.

  At this time, the light beam also enters the pressing member 50 integrated with the light guide layer 40. However, since the peripheral surface 51 of the pressing member 50 is not vertical but is inclined at an inclination angle of 45 ° or less, the reflection angle is reduced. Therefore, there is almost no change, and no light is leaked outside from the peripheral surface 51 of the presser 50 or the edge near the boundary with the light guide layer 40 to emit light. Accordingly, the light beam is guided while being totally reflected while being confined in the light guide layer 40 without leaking from the presser 50 to the outside.

  According to the above configuration, the peripheral surface 51 of the pressing element 50 is gradually inclined, and light rays are incident at a predetermined incident angle and are reflected almost completely at the interface. Therefore, the peripheral surface 51 of the pressing element 50 and the light guide layer 40 It is possible to effectively prevent light rays from leaking from the edge near the boundary. In particular, of the peripheral surface 51 of the presser 50, there is no leakage of light from the opposite side of the LED 21, in other words, the opposite surface 54 on the light guide direction side or the edge of the root thereof, and a good light beam. Can be obtained. Accordingly, the peripheral surface 51 of the presser 50 becomes a bright spot, and the presser 50 and the light emission pattern 41 are prevented from being excessively shined locally, the illumination of the operation key 31 is deteriorated, or the operation input layer 30 is It is possible to prevent the designability from being impaired.

  Further, the boundary portion 53 between the press contact surface 52 and the peripheral surface 51 of the presser 50 is not angular, and it is prevented from being changed by the R processing and the reflection angle of the light beam. It is possible to suppress an excessive increase in luminance of the child 50 and the light emission pattern 41. Further, since the presser 50 is formed in a truncated cone shape and the entire circumferential surface 51 is inclined, for example, the LEDs 21 are disposed at both ends of the surface of the circuit board 20, respectively, from opposite directions (for example, left and right in FIG. 2). Even if the light beam is guided, it is possible to effectively prevent the light beam from leaking from the peripheral edge 51 of the pressing member 50 and the edge near the boundary with the light guide layer 40, and the structure can be simplified and the manufacturing can be facilitated. become.

  Moreover, since the peripheral surface 51 of the pressing element 50 is inclined at an inclination angle of 5 ° or more, it can be expected to prevent interference between the peripheral surfaces 51 of the adjacent pressing elements 50. In addition, the light guide layer 40 and the pressing member 50 are not laminated separately, but the light guide layer 40 and the pressing member 50 are integrated and thinned. it can.

  Next, FIG. 4 shows a second embodiment of the present invention. In this case, each presser 50 is basically formed in a cylindrical shape, and of the peripheral surface 51 of this presser 50, At least the opposite side of the LED 21, in other words, the opposite surface 54 in the light guide direction is inclined so as to gradually spread at an inclination angle of 45 ° or less, and the boundary between the press contact surface 52 of the presser 50 and the inclined peripheral surface 51. The portion 53 is slightly rounded. The other parts are substantially the same as those in the above embodiment, and thus description thereof is omitted.

  In the present embodiment, it is obvious that the same operational effects as those of the above embodiment can be expected, and the shape of the presser 50 can be diversified.

  In the above embodiment, the presser 50 is formed on the back surface of the light guide layer 40, but the present invention is not limited to this, and may be formed on the surface of the light guide layer 40, for example. Moreover, in the said embodiment, although the plunger function and the leakage prevention function of the light beam were provided to the presser 50, it is not limited to this. For example, the presser 50 may be further provided with a lens function or the like to collect light, and the operation key 31 may be efficiently illuminated via the light emission pattern 41 with the collected light.

Hereinafter, examples of the light guide structure of the light guide layer according to the present invention will be described together with comparative examples.
[Example 1]
As shown in FIG. 5, a light guide layer for guiding the light from the LED is horizontally stacked on a circuit board having a metal dome mounted on the surface, and the light is diffusely irradiated on the surface of the light guide layer. A luminous pattern (made by Konica Minolta: product name CS-100) is installed above the light-emitting pattern with dots printed with white ink. Was molded.

  The LED was installed at the end of the surface of the circuit board and opposed to the opposing portion of the peripheral surface of the light guide layer at a slight interval, and the distance to the center of the presser was 30 mm. The light guide layer was molded using silicone rubber. The presser was integrally formed into a truncated cone shape located below the light emission pattern, and its entire peripheral surface was inclined so as to gradually spread at a predetermined inclination angle θ. The inclination angle θ of the peripheral surface of the presser was adjusted to 40 °.

When configured in the above-described structure, the LED was caused to emit light, and the light beam was irradiated to the opposing portion of the light guide layer, and the average luminance of the light emission pattern and the luminance of the bright spot portion, that is, the luminance of the peripheral surface of the presser were measured with a luminance meter. As a result of the measurement, the average luminance of the light emission pattern was 45 [cd / m ² ], and the luminance of the peripheral surface of the presser was 47 [cd / m ² ], and good measurement results were obtained.
In addition, although it measured also when the inclination | tilt angle (theta) of the surrounding surface of a presser was 40 degrees or less, the favorable measurement result was obtained similarly.

[Example 2]
Basically the same as in Example 1, but the inclination angle θ of the peripheral surface of the presser was changed to 45 °. If it comprised in such a structure, LED was light-emitted, the light ray was irradiated to the opposing part of the light guide layer, and the average brightness | luminance of the light emission pattern and the brightness | luminance of the presser peripheral surface were measured with the luminance meter. As a result of the measurement, the average luminance of the light emission pattern was 46 [cd / m ² ], and the luminance of the peripheral surface of the presser was 48 [cd / m ² ].

[Comparative Example 1]
Basically the same as in Example 1, but the inclination angle θ of the peripheral surface of the presser was changed to 50 °. After changing in this way, the LED was caused to emit light, and the light beam was irradiated to the opposite portion of the light guide layer, and the average luminance of the light emission pattern and the luminance of the peripheral surface of the presser were measured with a luminance meter. As a result of measurement, the average luminance of the light emission pattern was 46 [cd / m ² ] and the luminance of the peripheral surface of the presser was 85 [cd / m ² ], and the peripheral surface of the presser appeared to shine.

[Comparative Example 2]
Although basically the same as the embodiment, the presser was formed in a conventional cylindrical shape as shown in FIG. 6 and the inclination angle θ of the entire circumferential surface thereof was changed to 90 °.
If comprised in this way, LED was made to light-emit, the light beam was irradiated to the opposing part of the light guide layer, and the average brightness | luminance of the light emission pattern and the brightness | luminance of the presser peripheral surface were measured with the luminance meter. When measured, the average luminance of the light emission pattern was 49 [cd / m ² ] and the luminance of the presser peripheral surface was 185 [cd / m ² ]. The pressing element shone excessively as a bright spot.

  As described above, in the case of the example, since the inclination angle θ of the peripheral surface of the presser is 45 ° or less, unlike the comparative example, the peripheral surface of the presser becomes a bright spot and the presser and the light emission pattern are locally formed. Very little result was obtained with very little over-shine.

  The light guide layer light guide structure according to the present invention can be used in the fields of music equipment, home appliances, portable equipment, computer equipment, information communication equipment, in-vehicle equipment, and the like.

1 Cellular phone 20 Circuit board 21 LED (light source)
22 Metal dome (contact switch)
30 operation input layer 31 operation key 40 light guide layer 41 light emitting pattern 50 presser 51 peripheral surface 52 pressure contact surface 53 boundary 54 opposite surface

Claims (3)

A circuit board having a contact switch on the surface, and an operation input layer that opposes an operation key to the contact switch of the circuit board, and guides a light beam from a light source between the circuit board and the operation input layer. A light guide layer light guide structure for interposing a flexible light guide layer and irradiating at least an operation key of the operation input layer with a light beam guided to the light guide layer,
A substantially columnar pressing element is integrally formed on either one of the front and back surfaces of the light guide layer so as to be pressed on the contact switch of the opposite circuit board to be turned on, and at least of the peripheral surface of the pressing element opposite to the light source. The light guide structure of a light guide layer, wherein the opposite surface located on the side is inclined so as to gradually spread at an inclination angle of 45 ° or less.   The light guide layer light guide structure according to claim 1, wherein the presser is formed in a substantially truncated cone shape.   3. The light guide layer light guide structure according to claim 1 or 2, wherein the light guide layer is formed by rounding a boundary portion between a pressure contact surface that is in pressure contact with the contact switch of the presser and an inclined peripheral surface.

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