KR101518066B1 - Flexible printed circuit board, input module and mobile apparatus - Google Patents

Abstract

A flexible printed wiring board in which a front surface and a back surface of a conductive pattern are covered with an insulating layer, the flexible printed wiring board comprising a light introducing portion for introducing light from a light source into an insulating layer, and a light emitting portion for emitting light introduced from the light introducing portion, It is possible to reduce the number of components and reduce the sheet joining operation by providing the emitting portion and also to provide a flexible printed material capable of improving the feeling of clicking, the good dimming of the key input operation portion, Provided are a wiring board, an input module having a flexible printed wiring board, and a portable device having an input module.

Description

FLEXIBLE PRINTED CIRCUIT BOARD, INPUT MODULE AND MOBILE APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a flexible printed wiring board, an input module having the flexible printed wiring board, and a portable device having the module.

BACKGROUND ART [0002] Portable devices such as a mobile phone, a notebook computer, and a digital camera generally use input modules to perform required input operations. A flexible printed wiring board having a switching fixed contact on a conductive pattern may be used as a part of the input module so that a switch operation is performed in accordance with an input operation.

Further, portable apparatuses such as portable telephones are provided with a key input operation sheet having an input key, and the input keys and the like are often made to shine so as to facilitate key input operation in this key input operation sheet .

As a conventional technique for illuminating an input key of a key input operation sheet or the like, dimming is provided.

For example, Japanese Unexamined Patent Publication (Kokai) No. 2004-79442 discloses a method in which a switch 11 and an LED 13 are mounted on a flexible substrate 27 and a surface of a flexible substrate 27 other than the mounting portion is covered with a white paint 29 To thereby reflect light from the LED in the direction of the key sheet 26 with a white paint. According to this configuration, the number of sheets or the like to be combined can be reduced, the joining process can be simplified, and the module can be made thinner.

Further, as a prior art in which an input key or the like of a key input operation sheet is illuminated, a so-called light guide plate is combined as a member different from a key input operation sheet or a flexible printed wiring board (a board on which a conductive pattern or the like is mounted) .

For example, Japanese Patent Application Laid-Open No. 9-55143 discloses a key sheet 2 having a key top, a print plate 4 having a switch contact portion 6 and a chip LED 8, A key backlight illumination effect device comprising a light guide plate 3 made of acrylic resin is disclosed

Japanese Unexamined Patent Application Publication No. 2005-268165 discloses a lighting device including a circuit board 22 on which a key switch 25 and an LED for illumination 28 are mounted, a light guide plate 26 for guiding light generated from the LED 28, , And a key sheet (27) having a key top (31).

In the prior art disclosed in Japanese Patent Application Laid-Open No. 2004-79442, dimming is performed by a mechanism that only reflects light from a light source on the surface of the surface of the flexible substrate 27. Therefore, the light can not be guided to a distant place, and a problem that a large number of LEDs (light sources) are required, dim light is easily dispersed, and a problem that it is impossible to focus a desired position on a desired position.

In the prior art disclosed in Japanese Patent Laid-Open Nos. 9-55143 and 2005-268165, the number of light sources can be reduced by providing a light guide plate, thereby making it possible to reduce the thickness and cost. However, The light guide plate is provided separately from the key sheet or the flexible printed wiring board, which causes problems such as a decrease in click feeling and an increase in a joining step for joining the sheets together.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems in the prior art and to reduce the number of parts and alleviate the sheet joining operation and to improve the feeling of clicking, The present invention provides a flexible printed wiring board capable of further reducing the thickness of the flexible printed wiring board, an input module having the flexible printed wiring board, and a portable device having the input module.

A flexible printed wiring board according to the present invention is a flexible printed wiring board in which a front surface and a back surface of a conductive pattern are covered with an insulating layer and has a light introducing portion for introducing light from a light source into the insulating layer, And a light emitting portion that emits from the inside of the insulating layer to the outside of the layer is provided.

In addition to the first feature, the flexible printed wiring board of the present invention is characterized in that the insulating layer provided with the light introducing portion and the light emitting portion is a base film or a cover-lay film of a flexible printed wiring board .

In addition to the first or second feature, the flexible printed wiring board of the present invention is characterized in that the light emitting portion is provided in the vicinity of the switching fixed contact forming part of the conductive pattern.

In the flexible printed wiring board according to the present invention, in addition to any one of the first to third features, the light emitting portion is configured to emit light in the direction of the key top disposed above the switching fixed contact As a fourth feature.

In addition to the fourth feature, the flexible printed wiring board of the present invention is characterized in that the light emitting portion is formed by obliquely cutting the end face of the coverlay film surrounding the periphery of the switching fixed contact point .

The sixth aspect of the flexible printed wiring board of the present invention is that the light emitting portion is constituted by a dot pattern using a light beam provided on the insulating layer in addition to any one of the first to fourth features .

In addition to the sixth feature, the flexible printed wiring board of the present invention is the seventh feature that the dot pattern is formed by a pattern of concavo-convex shapes.

In addition to the sixth feature, the flexible printed wiring board of the present invention is characterized in that the dot pattern is formed by printing with ink containing a light scattering agent.

Further, the flexible printed wiring board of the present invention is characterized in that, in addition to any one of the sixth to eighth aspects, the dot pattern is located at a higher position from the light source.

The tenth feature of the flexible printed wiring board of the present invention is that the density adjustment is performed by adjusting the distance between the dot patterns in addition to the ninth feature.

In addition to the ninth feature, the flexible printed wiring board of the present invention has the eleventh feature that the density is adjusted by adjusting the size of the dot pattern.

In addition to any one of the sixth to eleventh features, the flexible printed wiring board of the present invention is characterized in that the dot pattern is provided only in a region corresponding to the key top.

In addition to the twelfth feature, the flexible printed wiring board of the present invention has the thirteenth feature that the dot pattern has a specific shape such as letters, numbers, and symbols.

The flexible printed wiring board of the present invention is characterized in that, in addition to any one of the first to thirteenth aspects, the insulating layer having the light introducing portion and the light emitting portion is made of any one of polycarbonate, polyethylene terephthalate and polyester 14 features.

Further, an input module of the present invention is characterized by comprising: the flexible printed wiring board according to any one of the first to fourteenth features; a key input operation sheet to be combined with the wiring board; And a dome-shaped movable contact sheet which is pressed to perform switching of the flexible printed wiring board.

In addition, the portable device of the present invention is the sixteenth feature that the portable device has the input module described in the fifteenth feature.

According to the flexible printed wiring board according to the first aspect of the present invention, since the insulating layer of the flexible printed wiring board itself is provided with the light introducing portion for introducing the light from the light source and the light emitting portion for emitting the introduced light, It is not necessary to use a light guide plate as a separate member, so that the click sense can be improved and the operation time for joining the light guide plate in the form of a layer can be omitted. Of course, the number of components can be reduced. In addition, since light can be introduced directly from the light source into the insulating layer of the flexible printed wiring board through the light introducing portion, and can be emitted from the light emitting portion to a desired place through the inside, Therefore, efficient dimming becomes possible. In addition, it is possible to provide a flexible printed wiring board capable of further reducing the thickness of the obtained module or device, an input module having the flexible printed wiring board, and a portable device having the input module.

According to the flexible printed wiring board according to the second aspect of the present invention, in addition to the action and effect of the first aspect of the present invention, the insulating layer provided with the light introducing portion and the light emitting portion is provided on the base film of the flexible printed wiring board, As the film is used, the function and action of light introduction and emission can be used both as a base film made of a conductive pattern substrate or as a coverlay film for insulating a conductive pattern, if necessary.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, the light-emitting portion is formed in the vicinity of the switching fixed contact forming part of the conductive pattern The light emitted from the vicinity of the switching fixed contact enables dimming in the vicinity of switching.

According to the flexible printed wiring board according to the fourth aspect of the present invention, in addition to the operation effects of any one of the first to third aspects of the present invention, the light emitting portion is disposed above the switching fixed contact Since the light is emitted in the direction of the key top, light control of the key top can be selected and effectively performed.

According to the flexible printed wiring board according to the fifth aspect of the present invention, in addition to the operation effect of any one of the first to fourth aspects of the present invention, the light emitting portion surrounds the fixed contact for switching The light guided from the light introducing portion through the coverlay film can reliably be emitted obliquely upward or obliquely downward from the periphery of the switching fixed contact point, It is possible to indirectly dim the light directly or through the reflecting means.

According to the flexible printed wiring board according to the sixth aspect of the present invention, in addition to the action and effect of the fourth aspect of the present invention, the light emitting portion is constituted by the dot pattern for use in the light plate provided on the insulating layer, By the dot pattern, the total reflection condition of the light guided through the inside of the insulating layer can be canceled and scattered, and the light can be surely emitted in the direction of the key top.

According to the flexible printed wiring board according to the seventh aspect of the present invention, in addition to the action and effect of the sixth aspect of the present invention, the dot pattern is formed by a pattern of irregularities, Light can be reliably scattered at the position of the pattern of the physical uneven shape and can be emitted in the key top direction.

According to the flexible printed wiring board according to the eighth aspect of the present invention, since the dot pattern is formed by printing with the ink containing the light scattering agent, in addition to the operation effect of the sixth aspect of the present invention, The light which has been guided to the total reflection state in the layer can be surely scattered at the position of the print pattern including the light scattering agent and released in the key top direction.

According to the flexible printed wiring board according to the ninth aspect of the present invention, in addition to the operation effects according to any one of the sixth to eighth aspects of the present invention, the dot pattern is farther away from the light source, Therefore, the farther the light intensity is reduced, the better the light emission efficiency becomes, and accordingly, the uniform light control becomes possible irrespective of the position of the light source.

According to the flexible printed wiring board according to the tenth feature of the present invention, since the density adjustment is performed by adjusting the distance between the dot patterns in addition to the function and effect of the ninth aspect of the present invention, The density between the dot patterns increases as the position is reduced, so that the light emission efficiency is improved, and homogeneous dimming becomes possible irrespective of the position of the light source.

According to the flexible printed wiring board according to the eleventh aspect of the present invention, the density is adjusted by adjusting the size of the dot pattern in addition to the operation effect according to the ninth aspect of the present invention. Therefore, The dot becomes larger and the light emitting efficiency becomes better, and homogeneous dimming becomes possible irrespective of the position of the light source.

According to the flexible printed wiring board of the twelfth aspect of the present invention, the dot pattern is provided only in the region corresponding to the key top, and in addition to the effect of any one of the sixth to eleventh aspects of the present invention, It is possible to concentrate the light reflected and emitted from the dot pattern on the key top. Therefore, the key top can be illuminated more than the other areas.

According to the flexible printed wiring board of the thirteenth aspect of the present invention, in addition to the action and effect of the twelfth aspect of the present invention, the dot pattern has a specific shape such as letters, numbers, Therefore, a specific shape of letters, numbers, symbols, etc. by light can be brought to the keytop side.

According to a fourteenth aspect of the present invention, in addition to the functional effects of any one of the first to thirteenth aspects of the present invention, the insulating layer provided with the light introducing portion and the light emitting portion is made of poly Carbonates, polyethylene terephthalates, and polyesters, it is possible to exert an effect as a good light-guiding layer.

The input module according to the fifteenth aspect of the present invention includes the flexible printed wiring board according to any one of the first to fourteenth aspects, a key input operation sheet combined with the wiring board, By providing at least the dome-shaped movable contact sheet which is pressed by the input operation on the sheet and performs switching of the flexible printed wiring board, the product can be further reduced in thickness and the number of components can be reduced. In addition, since the light guide plate is unnecessary, it is possible to improve the click feeling and omit the time for the light guide plate joining operation. In addition, it is possible to select a desired place such as an input operation unit for dimming, and efficient dimming becomes possible.

Further, according to the portable device according to the sixteenth aspect of the present invention, since the input module described in the fifteenth feature is provided, it is possible to further reduce the thickness, the click feeling, and the number of components of the product . In addition, it is possible to select a desired place such as an input operation unit for dimming, and efficient dimming becomes possible.

According to the flexible printed wiring board, the input module and the portable device of the present invention, the insulating layer of the flexible printed wiring board is provided with a light introducing portion for introducing the light from the light source into the insulating layer, It is not necessary to use a light guide plate as a separate member, so that it is possible to improve the click feel, the thickness of the product, and the number of components. Of course, the light from the light source can be efficiently guided to a desired place and dimmed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A flexible printed wiring board, an input module, and a portable device according to a first embodiment of the present invention will be described with reference to the following drawings to help understand the present invention. However, the following description is an embodiment of the present invention and is not intended to limit the scope of the claims.

1 shows a portable telephone as a portable device according to a first embodiment of the present invention. Fig. 2 is a plan view of an input module of the cellular phone shown in Fig. 1, Fig. 3 is a cross-sectional view showing a part of the input module shown in Fig. 2, and Fig. 4 is a view showing an example of a light source and a light-

1, the mobile phone 1 according to the present embodiment includes an input unit 1a and a display unit 1b. The display portion 1b is capable of opening and closing the input portion 1a with the hinge portion 1c therebetween.

2 and 3, the input unit 1a is provided with an input module 2 in its case. The input module 2 is provided with a key input operation sheet 10, a dome-shaped movable contact sheet 20, a light source 30 such as an LED, and a flexible printed wiring board 40.

The key input operation sheet 10 is a portion for performing an input operation and has a key top 11 exposed to the input portion 1a. On the opposite side of the key top 11, a presser bar 12 may be provided as necessary to protrude. The key input operation sheet 10 can be formed of a sheet having appropriate elasticity such as rubber.

The dome-shaped movable contact sheet 20 is a sheet having a dome-shaped movable contact 21 called a metal dome, and can be formed of a soft elastic sheet such as rubber. The dome-shaped movable contact sheet 20 is provided on the flexible printed wiring board 40.

The light source 30 may be composed of, for example, an LED. This light source 30 is provided on the flexible printed wiring board 40.

The flexible printed wiring board 40 includes a base film 41, a conductive pattern 42 formed on the upper surface thereof, and a coverlay film 43 covering the conductive pattern 42. In other words, the flexible printed wiring board 40 has a configuration in which the conductive pattern 42 and the front and back surfaces thereof are sandwiched by the insulating base film 41 and the coverlay film 43.

The base film 41 may be made of an insulating resin material.

The conductive pattern 42 can be formed by, for example, forming a pattern of copper foil on the base film 41. [

The coverlay film 43 may also be made of an insulating resin material.

When the base film 41 and the coverlay film 43 are integrated using an adhesive, an adhesive layer (not shown) is present.

The conductive pattern 42 is provided with a first fixed contact 421 and a second fixed contact 422 as a switching fixed contact 420 in a part thereof.

The first fixed contact 421 is an island-shaped fixed contact and the second fixed contact 422 is an annular fixed contact that surrounds the first fixed contact 421.

On the second fixed contact 422, the dome-shaped movable contact 21 of the dome-shaped movable contact sheet 20 is provided correspondingly.

When the key top 11 of the key input operation sheet 10 is pressed down, the central portion of the dome-shaped movable contact 21 of the dome-shaped movable contact sheet 20 is pushed downward to sink to the first fixed contact 421, Respectively. The first fixed contact 421 and the second fixed contact 422 are made conductive through the dome-shaped movable contact 21 by this grounding.

The coverlay film 43 functions to cover and insulate the conductive pattern 42 formed on the base film 41. However, in the present embodiment, the light from the light source 30 also serves as a function of guiding light through the inside thereof.

Therefore, in the present embodiment, the coverlay film 43 is an insulating layer that guides light, and an insulating material having good light transmission properties such as polycarbonate, polyethylene terephthalate, and polyester is used.

The coverlay film 43 is provided with a light introducing portion 431 for receiving the light from the light source 30 into its own layer and a light emitting portion 432 for emitting the light guided in the layer out of the layer have.

The light introducing portion 431 may be a thicker surface of the coverlay film 43 facing the light emitting portion of the light source 30, for example. Light that has entered the layer of the coverlay film 43 from the light introducing portion 431 travels in the layer while being totally reflected on the front and back surfaces of the coverlay film 43.

In order to smoothly receive the light from the light source 30, the light introducing portion 431 of the coverlay film 43 is provided with a cover layer film 43 which faces the light source 30 A part or all of the cross section may be formed into a tapered shape to increase its thickness.

The light source 30 may be provided with a condensing means such as a lens 31 for efficiently guiding light to the thin coverlay film 43.

The light emitting portion 432 is provided in the vicinity of the switching fixed contact 420 of the coverlay film 43 in the present embodiment. More specifically, the light emitting portion 432 is provided around the second fixed contact 422 of the switching fixed contact 420.

In the present embodiment, the coverlay film 43 is not covered with the switching fixed contact 420 and is exposed. The cover end portion of the coverlay film 43 around the second fixed contact 422 is cut obliquely upward to form the light-emitting portion 432 as a cut portion. The light that has passed through the layer of the coverlay film 43 is emitted out of the layer from the cut portion.

The light is emitted obliquely upward from the light emitting portion 432 around the second fixed contact 422 so that the key top of the key input operation sheet 10 disposed above the switching fixed contact 420 Light is emitted in the direction of the key top 11 (indicated by an arrow in Fig. 3), and the key top 11 is dimmed. In this case, the light emitted from the light emitting portion 432 passes around the dome-shaped movable contact 21, passes through the dome-shaped movable contact sheet 20, and travels toward the key top 11. Therefore, the dome-shaped movable contact sheet 20 is made of the above-described light-permeable material.

Next, a flexible printed wiring board and an input module according to a second embodiment of the present invention will be described. The portable device having the flexible printed wiring board and the input module according to the second embodiment is the same as the portable device shown in Fig. 1 described above.

5 is a cross-sectional view for explaining the configuration of the input module, and corresponds to Fig. 3 above. Fig. 6 shows an example of adjusting the density of the dot pattern by the distance between the dot patterns. Fig. 7 shows an example of adjusting the density of the dot pattern by the size of the dot pattern. In the case of providing only the area corresponding to the key top, the shape of the dot pattern is formed into a specific shape such as a letter, a number, and a symbol in accordance with the shape of the key top or the like.

5, the input module 3 of the second embodiment includes a key input operation sheet 50, a dome-shaped movable contact sheet 60, a light source 70, a flexible printed wiring board 80, (90). The key input sheet 10, the dome-shaped movable contact sheet 60, the light source 70, and the flexible printed wiring board 80 in the first embodiment are the same as the key input sheet 10, The sheet 20, the light source 30, and the flexible printed wiring board 40 shown in Fig.

The key input operation sheet 50 is provided with a key top 51. The key top 51 has the same function and function as the key top 11 in the first embodiment. In the present embodiment, nothing corresponding to the pressure bar 12 is provided.

The dome-shaped movable contact sheet (60) has a dome-shaped movable contact (61). These correspond to the dome-shaped movable contact sheet 20 and dome-shaped movable contact 21 according to the first embodiment.

The dome-shaped movable contact sheet 60 differs from the input module 2 of the first embodiment in that the dome-shaped movable contact sheet 60 is disposed on the opposite side of the flexible printed wiring board 80 from the key input operation sheet 50.

The light source 70 corresponds to the light source 30 according to the first embodiment.

However, in the second embodiment, light emitted from the light source 70 is introduced into the layer of the base film 81 of the flexible printed circuit board 80, which will be described later.

The flexible printed wiring board 80 includes a base film 81, a conductive pattern 82, and a coverlay film 83. The conductive pattern 82 is provided with a first fixed contact 821 and a second fixed contact 822 as a switching fixed contact 820 in a part thereof. These points are the same as those of the conductive pattern 42 according to the first embodiment.

However, the flexible printed wiring board 80 according to the second embodiment is different from the flexible printed wiring board 20 according to the first embodiment in that the directions are reversed.

The support substrate 90 is provided for more reliably switching operation when the key top 51 of the key input operation sheet 50 is operated. The key top 51 and the dome-shaped movable contact 61 And a pressure bar 91 is provided at a corresponding position.

When the key top 51 is pressed, the pressure bar 91 of the support substrate 90 pushes the dome-shaped movable contact 61 through the dome-shaped movable contact sheet 60, .

In the second embodiment, the light from the light source 70 is configured to be guided into the base film 81 of the flexible printed wiring board 80.

That is, the base film 81 forms the conductive pattern 82 thereon. In this embodiment, the base film 81 serves also as a function of guiding light from the light source 70 through the inside thereof.

Therefore, in the second embodiment, as the insulating film for guiding light, an insulating material having good light transmittance such as polycarbonate, polyethylene terephthalate, and polyester is used for the base film 81.

The base film 81 is provided with a light introducing portion 811 for receiving the light from the light source 70 that can be provided on the base film 81 and the supporting substrate 90 into its own layer, And a light emitting portion 812 for emitting the guided light out of the layer is provided.

The light introducing portion 811 may be a thicker surface of the base film 81 facing the light emitting portion of the light source 70, for example. Light entering from the light introducing portion 811 into the layer of the base film 81 is totally reflected on the front and back surfaces of the base film 81 and proceeds in the layer.

The light emitting portion 812 is provided in the vicinity of the fixed contact 820 for switching of the base film 81 in the present embodiment. More specifically, the light emitting portion 812 is provided on the upper surface of the base film 81 corresponding to the fixed contact 820 of the base film 81, that is, the key top 51.

In the second embodiment, the light emitting portion 812 is constituted by the dot patterns P for use in light use. This dot pattern P for use in the light panel can be constructed by scattering light in the direction of the key top 51.

The dot pattern P can be formed by a pattern of concavo-convex shapes. In this case, the concave-convex shape can be formed by hot stamping, injection molding, micro-blasting, or other methods.

The dot pattern P can be formed by printing with ink containing a light-scattering agent.

The light that has passed through the layer of the base film 81 by the dot pattern P is emitted from the cut portion to the outside of the layer and advances in the direction of the key top 51 to dim the key top 51.

As the configuration of the dot pattern P, the dot pattern P can be formed at a higher density as far as the dot pattern P is located farther from the light source 70. Thus, the plurality of key tops 51 can be uniformly dimmed.

The adjustment of the density of the dot pattern P can be performed by adjusting the distance between the dot patterns P, that is, the distance from the light source 70, as shown in Fig. 6, by shortening the distance between the dot patterns P have.

The density of the dot pattern P can be adjusted by adjusting the size of the dot pattern P, that is, the position farther from the light source 70, as shown in Fig. 7 have.

In addition, by providing the dot pattern P only in the area corresponding to the key top 51, it is possible to effectively dim the key top 51 effectively.

8, the dot pattern P may have a pattern shape corresponding to the shape of the key top 51 or the like, and may be a character, a number, And a symbol. Accordingly, it becomes possible to display the specific shape in a state in which the specific shape is floated by the light.

In the case where the dot pattern P is provided only in the area corresponding to the key top 51, each dot pattern P may be formed as an aggregate of small dots p as shown in Fig. Thus, the pattern shape of the dot pattern P can be easily matched to the shape of the key top 51 or the like.

The input module 3 having the flexible printed wiring board 80 according to the second embodiment described above can be applied to a portable device such as a cellular phone shown in Fig. Such a portable device is also included in the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used industrially as a portable device such as a cellular phone, an input module used therein, and a flexible printed wiring board used therefor.

1 is a perspective view showing a cellular phone as a portable device according to a first embodiment of the present invention,

2 is a plan view of an input module of a portable telephone,

3 is a sectional view showing a part of an input module,

4 is a view showing an example of a light source and a light introducing portion,

5 is a sectional view for explaining a configuration of an input module according to a second embodiment of the present invention,

6 is a diagram showing an example of adjusting the density of the dot pattern to a distance between the dot patterns,

7 is a diagram showing an example of adjusting the density of a dot pattern to the size of a dot pattern,

8 is a view showing an example in which the shape of the dot pattern is formed into a specific shape such as a letter, a number and a symbol in accordance with the shape of the key top or the like when the dot pattern is provided only in the area corresponding to the key top,

9 is a view showing an example in which each dot pattern is constituted by a small dot pattern in order to facilitate the matching of the shape of each dot pattern to the shape of the key top when the dot pattern is provided only in the area corresponding to the key top .

DESCRIPTION OF THE REFERENCE NUMERALS

1: portable switch 1a: input part

1b: display portion 1c: hinge portion

2: input module 10: key input operation sheet

20: dome-shaped movable contact sheet 30: light source

40: Flexible printed wiring board 11: Key top

Claims (16)

1. A flexible printed wiring board in which the front and back surfaces of a conductive pattern are covered with an insulating layer, In the insulating layer, A light introducing portion for introducing the light from the light source into the insulating layer, A light emitting portion for emitting the light introduced from the light introducing portion from the inside of the insulating layer to the outside of the layer; In addition, Wherein the insulating layer provided with the light introducing portion and the light emitting portion is a coverlay film of a flexible printed wiring board, The flexible printed wiring board is provided below the dome-shaped movable contact sheet which is pressed by an input operation on the key input operation sheet to perform switching of the flexible printed wiring board, Constituent And the flexible printed wiring board. 1. A flexible printed wiring board in which the front and back surfaces of a conductive pattern are covered with an insulating layer, In the insulating layer, A light introducing portion for introducing the light from the light source into the insulating layer, A light emitting portion for emitting the light introduced from the light introducing portion from the inside of the insulating layer to the outside of the layer; In addition, Wherein the insulating layer provided with the light introducing portion and the light emitting portion is a base film of a flexible printed wiring board, The flexible printed wiring board is provided between a key input operation sheet for performing a predetermined operation and a dome-shaped movable contact sheet which is pressed by an input operation in the key input operation sheet to perform switching of the flexible printed wiring board, Constitute And the flexible printed wiring board. 3. The method according to claim 1 or 2, And the light emitting portion is provided in the vicinity of the switching fixed contact forming part of the conductive pattern. 3. The method according to claim 1 or 2, Wherein the light emitting portion is configured such that light is emitted in the direction of the key top disposed above the switching fixed contact forming part of the conductive pattern. The method according to claim 1, Wherein the light emitting portion is constituted by obliquely cutting the end face of the coverlay film surrounding the periphery of the switching fixed contact forming part of the conductive pattern. 3. The method according to claim 1 or 2, Wherein the light emitting portion is constituted by a dot pattern using a light beam provided on the insulating layer. The method according to claim 6, Wherein the dot pattern is formed by a concavo-convex pattern. The method according to claim 6, Wherein the dot pattern is formed by printing with ink containing a light scattering agent. The method according to claim 6, Wherein the dot pattern is formed at a higher density in a position far from the light source. 10. The method of claim 9, And the density is adjusted by adjusting the distance between the dot patterns. 10. The method of claim 9, And the density is adjusted by adjusting the size of the dot pattern. The method according to claim 6, Wherein the dot pattern is provided only in a region corresponding to the key top. 13. The method of claim 12, Wherein the dot pattern has a specific shape of letters, numbers, and symbols. 3. The method according to claim 1 or 2, Wherein the insulating layer provided with the light introducing portion and the light emitting portion is made of any one of polycarbonate, polyethylene terephthalate and polyester. The flexible printed wiring board according to claim 1 or 2, A key input operation sheet to be combined with the wiring board, A dome-shaped movable contact sheet which is pressed by an input operation in the key input operation sheet to perform switching of the flexible printed wiring board And at least one input module. A portable device comprising the input module according to claim 15.

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