TWI567589B - Back light module of keyboard - Google Patents

Description

Keyboard backlight module

The present invention relates to a backlight module, and more particularly to a backlight module suitable for a keyboard.

As shown in FIG. 1, the backlight module 10 of the conventional illuminated keyboard has a flexible circuit board 11 generally having an extension portion 12 extending outwardly to extend electrically to the connector connector of the system. However, in order to match the position of the connector joint of the system, the shape of the flexible circuit board 11 becomes complicated, causing excess waste to be generated after the board is cut. Further, in this design, the flexible circuit board 11 uses a connector joint 13, and the membrane switch layer 14 also uses a connector joint 15, which causes an increase in assembly complexity and an increase in manufacturing cost.

Therefore, there is a need to propose a solution that simplifies the shape and circuit design of a flexible circuit board.

Therefore, the present invention provides a backlight module that simplifies the appearance and circuit design of a flexible circuit board.

According to an embodiment of the invention, a backlight module suitable for a keyboard is proposed. The backlight module comprises a membrane switch layer, a flexible circuit board, a plurality of light sources and a light guide plate. The membrane switch layer has a first connecting unit, and the first connecting unit has There are several first lines and several second lines. The flexible circuit board partially overlaps the membrane switch layer, and the flexible circuit board has a plurality of third lines, and the third lines are electrically connected to the second lines. The light source is disposed on the flexible circuit board, and the light sources are electrically connected to the third lines. The light guide plate has a plurality of holes for accommodating the light sources.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

10, 130‧‧‧Soft circuit board

11‧‧‧Extension

100, 200‧‧‧ backlight module

110‧‧‧Light source

110u‧‧‧Lighting surface

120‧‧‧membrane switch layer

121‧‧‧First connection unit

1211‧‧‧First line

1212‧‧‧second line

1213‧‧‧ first floor

1214‧‧‧ second floor

1214a‧‧‧Second opening

1215‧‧‧ spacer

1215a‧‧‧First opening

122‧‧‧ Subject

131‧‧‧Second connection unit

1311‧‧‧ third line

132‧‧‧ board

135‧‧‧ conductive adhesive

140‧‧‧Light guide plate

150‧‧‧reflector

160‧‧‧floor

170‧‧‧Support institutions

180‧‧‧Key Cap

D1‧‧‧ first direction

D21‧‧‧ second direction

D22‧‧‧ third direction

L1‧‧‧Light

FIG. 1 is a diagram showing the appearance of a flexible circuit board of a conventional backlight module.

FIG. 2A is a rear view of a backlight module according to an embodiment of the invention.

FIG. 2B is a front view of the backlight module of FIG. 2A.

Figure 2C is a cross-sectional view of the backlight module of Figure 2A taken along the direction 2C-2C'.

FIG. 2D is a schematic diagram showing the first connecting unit and the second connecting unit of FIG. 2A being reversely folded.

FIG. 3A is a rear view of a backlight module according to another embodiment of the present invention.

FIG. 3B is a schematic diagram showing the reverse connection of the first connecting unit of FIG. 3A.

Figure 3C is a cross-sectional view of the backlight module of Figure 3B taken along the direction 3C-3C'.

FIG. 2A is a rear view of the backlight module 100 according to an embodiment of the invention, FIG. 2B is a front view of the backlight module 100 of FIG. 2A, and FIG. 2C is a second embodiment of the backlight module of FIG. 100 is a cross-sectional view of the direction 2C-2C'. The backlight module 100 includes a plurality of light sources 110, a membrane switch layer 120, a flexible circuit board 130, a conductive paste 135 (FIG. 2C), a light guide plate 140, and a reflection sheet 150.

As shown in FIGS. 2B and 2C, the light source 110 is disposed on the flexible circuit board 130. The light sources 110 are arranged along the first direction D1. Each light source 110 has a light emitting surface 110u. The light emitting surface 110u faces the second direction D21 or the third direction D22. The second direction D21 and the third direction D22 emit light, and the second The direction D21 is substantially opposite to the third direction D22, and the first direction D1 is substantially perpendicular to the second direction D21 or the third direction D22. Since the light emitting surface 110u of the adjacent two light sources 110 respectively faces the opposite second direction D21 and the third direction D22, the light emitting range of the light source 110 may cover the entire membrane switch layer 120 along the second direction D21 and the third direction D22. In addition, the flexible circuit board 130 is located in the middle area of the membrane switch layer 120, so that the difference in optical path length between the light source 110 and the backlight module 100 is reduced, thereby uniformly distributing the light.

As shown in FIGS. 2A and 2C , the membrane switch layer 120 includes a first connecting unit 121 and a main body 122 , wherein the first connecting unit 121 is electrically connected to the main body 122 , and a plurality of membrane switches (not shown) are located in the main body 122 . It is not located at the first connection unit 121. The flexible circuit board 130 includes a second connection unit 131, wherein the first connection unit 121 is electrically connected to the second connection unit 131. The first connection unit 121 of the membrane switch layer 120 has a plurality of first lines 1211 and a plurality of second lines 1212. The second connecting unit 131 of the flexible circuit board 130 has a plurality of third lines 1311 electrically connected to the second lines 1212. As shown in FIG. 2C, the second line 1212 and the third line 1311 are arranged to face each other in the direction in which the membrane switch layer 120 and the flexible circuit board 130 are arranged. The light source 110 is electrically connected to the third lines 1311, and the light source 110 can be electrically connected to the membrane switch layer through the third line 1311. The second line 1212 of 120 receives external power. In addition, in order to clearly show the various layers of components in the backlight module 100, FIG. 2C intentionally enlarges the components. In fact, the height of the backlight module 100 is about 0.3 millimeters (mm), and the overall height of the keyboard (top surface of the key cap 180 to the bottom plate) The height of the 160 base) is approximately 5 mm.

In this embodiment, the second line 1212 and the third line 1311 are power lines. A power source (not shown) can supply power to the light source 110 through the second line 1212 and the third line 1311 to drive the light source 110 to emit light. Further, the number of the second lines 1212 is two, which are the first positive line and the first negative line, respectively. The number of the third lines 1311 is two, which are respectively a second positive line and a second negative line, wherein the first positive line is electrically connected to the second positive line, and the first negative line is electrically connected to the second negative line, so that the light source 110 is The first positive line and the first negative line are supplied to the second positive line and the second negative line of the flexible circuit board 130 to drive the light source 110 to emit light. In this embodiment, the flexible circuit board 130 is electrically connected only through the membrane switch layer 120. That is to say, the flexible circuit board 130 is not directly electrically connected to other components except for being directly electrically connected to the membrane switch layer 120.

Since the membrane switch layer 120 provides a line for electrically connecting the flexible circuit board 130, the flexible circuit board 130 does not require special consideration for the layout of the externally connected wiring. In this way, the shape of the flexible circuit board 130 can be simplified (in consideration of the layout of the external electrical connection, a more complicated flexible circuit board shape needs to be designed), so that the flexible circuit board 130 can be cut during the board cutting stage. Reducing waste generation and allowing the same sheet to cut a greater number of flexible circuit boards 130. In this embodiment, the flexible circuit board 130 is elongated, for example, rectangular, but may be other polygons.

As shown in FIG. 2C, the first connecting unit 121 includes a first layer 1213, a second layer 1214, and a spacer layer 1215. The first line 1211 (not shown in FIG. 2C) and the second line 1212 may be formed in the first On layer 1213. The spacer layer 1215 is located between the first layer 1213 and the second layer 1214, and the spacer layer 1215 and the second layer 1214 respectively have a first opening 1215a and a second opening 1214a, and the first line 1211 and the second line 1212 are from the first The opening 1215a and the second opening 1214a are exposed. In addition, the elastomer is omitted in FIG. 2C, and the elastic system provides a button restoring force and triggers a switch on the membrane switch layer 120.

The conductive paste 135 is formed in the first opening 1215a and the second opening 1214, and electrically connects the second line 1212 and the third line 1311 through the first opening 1215a and the second opening 1214a, so that power can be transmitted through the second line. The 1212 and third line 1311 are transmitted to the light source 110 to drive the light source 110. In one embodiment, the conductive paste 135 is, for example, an anisotropic conductive film (ACF). As shown in FIG. 2C, since the second line 1212 and the third line 1311 are electrically connected through the first opening 1215a and the second opening 1214a located outside the main body 122, any holes can be avoided in the main body 122, which simplifies The design of the body 122.

As shown in FIG. 2C, the light guide plate 140 is disposed between the flexible circuit board 130 and the membrane switch layer 120. The light L1 of the light source 110 is guided by the light guide plate 140 and then directed to the 180-key cap. In addition, the light guide plate 140 has a plurality of holes 140a (only one is shown in FIG. 2C) for accommodating a plurality of light sources 110, respectively.

As shown in FIG. 2C, the backlight module 100 can be combined with the bottom plate 160, at least one supporting mechanism 170 and at least one keycap 180 to form a keyboard, wherein the bottom plate 160 is thin. The membrane switch layer 120 is between the support mechanism 170. The support mechanism 170 connects the bottom plate 160 and the key cap 180 to lift and lower the key cap 180 to move the key cap 180 up and down, so that the key cap 180 moves relative to the metal bottom plate between the unpressed position and the pressed position. As shown in FIG. 1C, the support mechanism 170 is, for example, a scissor mechanism.

FIG. 2D is a schematic diagram showing the first connecting unit 121 and the second connecting unit 131 reversing in FIG. 2A. In order to reduce the area of the backlight module 100, the first connecting unit 121 and the second connecting unit 131 may be folded back. As shown in the figure, the flexible circuit board 130 further includes a board body 132, wherein the board body 132 is connected to the second connecting unit 131. After folding back, the second connecting unit 131 of the flexible circuit board 130 and the board body 132 overlap each other.

FIG. 3A is a rear view of the backlight module 200 according to another embodiment of the present invention, FIG. 3B is a schematic diagram showing a reverse folding of the first connecting unit 121 of FIG. 3A, and FIG. 3C is a third drawing of FIG. A cross-sectional view of the backlight module 200 in the direction 3C-3C'. The backlight module 200 includes a plurality of light sources 110 (not shown), a membrane switch layer 120, a flexible circuit board 130, a conductive paste 135, a light guide plate 140, and a reflective sheet 150.

The membrane switch layer 120 includes a first connection unit 121 and a body 122. Different from the backlight module 100 of the foregoing embodiment, the entire flexible circuit board 130 of the present embodiment overlaps with the main body 122 of the membrane switch layer 120. In detail, as shown in FIG. 3B, after the first connecting unit 121 of the membrane switch layer 120 is folded back, the first connecting unit 121 partially overlaps with the flexible circuit board 130.

As shown in FIG. 3C, the bottom plate 160, the support mechanism 170 and the key cap 180 may be disposed on the membrane switch layer 120, and the relative relationship is similar to that of FIG. 2C, and details are not described herein again. In addition, similar to the structure shown in FIG. 2C, the first connection of FIG. 3C The unit 121 includes a first layer 1213, a second layer 1214, and a spacer layer 1215. The first line 1211 (not shown in FIG. 3C) and the second line 1212 are formed on the first layer 1213. The spacer layer 1215 is located between the first layer 1213 and the second layer 1214, and the spacer layer 1215 and the second layer 1214 respectively have a first opening 1215a and a second opening 1214a, and the second line 1212 is from the first opening 1215a and the The second opening 1214a is exposed. The conductive paste 135 is electrically connected to the second line 1212 and the third line 1311 through the first opening 1215a and the second opening 1214a, so that a power source (not shown) can be transmitted to the light source 110 through the second line 1212 and the third line 1311. In addition, in order to clearly show the various layer elements in the backlight module 100, FIG. 3C intentionally shows each element in an enlarged manner.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧Backlight module

120‧‧‧membrane switch layer

121‧‧‧First connection unit

1211‧‧‧First line

1212‧‧‧second line

122‧‧‧ Subject

130‧‧‧Soft circuit board

131‧‧‧Second connection unit

1311‧‧‧ third line

Claims (9)

A backlight module suitable for a keyboard, comprising: a membrane switch layer having a first connecting unit, the first connecting unit having a plurality of first lines and a plurality of second lines; and a flexible circuit board having a plurality of strips a third line electrically connecting the second lines; a plurality of light sources disposed on the flexible circuit board, the light sources being electrically connected to the third lines; and a light guide plate having a plurality of holes The light source is configured to receive the light source; wherein the second line and the third line are disposed opposite to each other along a direction in which the membrane switch layer and the flexible circuit board are arranged. The backlight module of claim 1, wherein the flexible circuit board is located in an intermediate portion of the membrane switch layer. The backlight module of claim 1, wherein the flexible circuit board is elongated. The backlight module of claim 1, wherein the flexible circuit board is rectangular. The backlight module of claim 1, wherein the soft battery The road board includes a board body and a second connecting unit connected to the first connecting unit, the second connecting unit overlapping the board system. The backlight module of claim 1, wherein the first connecting unit comprises a first layer, a second layer, a spacer layer, and the first lines and the second lines, the spacer layer Between the first layer and the second layer, the spacer layer and the second layer respectively have a first opening and a second opening, and the first line and the second line are disposed in the first layer One layer is exposed from the first opening and the second opening. The backlight module of claim 6, further comprising: a conductive adhesive electrically connecting the third circuit and the first circuit of the flexible circuit board through the first opening and the second opening Connecting the first lines of the unit. The backlight module of claim 1, wherein the flexible circuit board is externally electrically connected only through the thin film barrier layer. The backlight module of claim 1, wherein the second lines comprise a first positive line and a first negative line, and the third lines comprise a second positive line and a second negative line. The first positive line is electrically connected to the second positive line, and the first negative line is electrically connected to the second negative line.