JP2009004612A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board capable of satisfactorily radiating heat emitted by a light emitting element. <P>SOLUTION: The printed wiring board is constituted so that a wiring part is provided with first and second connection lands 70 and 71 where a first light emitting element 21 emitting a first light emission color can be mounted and third and fourth connection lands 80 and 81 where a second light emitting element 2 emitting a second light emission color can be mounted, wherein the first connection land 70 and third connection land 80 are connected together through a conduction part C1 in a state in which the first light emitting element 21 is mounted on the first and second connection lands 70 and 71. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printed wiring board in which a light emitting element is mounted on a pair of connection lands provided in a wiring pattern.

  Conventionally, as this type of printed wiring board, for example, the one described in Patent Document 1 below is known. Such a printed wiring board described in Patent Document 1 is a light emitting element composed of a light emitting diode that emits a predetermined color to a pair of connection lands 110 and 120 provided on a predetermined wiring pattern (wiring portion) 100 as shown in FIG. 130 is implemented. The heat generated when the light emitting element 130 emits light can be dissipated into the atmosphere through the connection lands 110 and 120. That is, this means that the connection lands 110 and 120 have a function as a heat radiating part that radiates heat generated when the light emitting element 130 emits light into the atmosphere.

Note that the printed wiring board on which the light emitting element 130 is mounted in this way is, for example, a light emitting element between the illuminated member and the printed wiring board so as to uniformly illuminate an illuminated member (liquid crystal display panel or the like) (not shown). A configuration in which a case body is disposed so as to surround 130, and a diffusion plate is disposed between the case body and an illuminated member is known. According to such a configuration, the illumination light emitted from the light emitting element 130 mounted on the printed wiring board is substantially uniformed by the diffusion plate, so that the illuminated member is uniformly illuminated. Further, when the member to be illuminated is a liquid crystal display panel, the light emitting element 130 mounted on the printed wiring board serves as a backlight light source that illuminates the liquid crystal display panel from behind.
JP 2006-1000068 A

  By the way, in the printed wiring board mentioned above, the design specification change (namely, new model design) that only the luminescent color of the light emitting element 130 changes according to a vehicle model may exist, for example. In this case, for example, when the light emission color of the light emitting element 130 is changed from orange to white due to a change in design specifications, the light emission brightness of the white light emitting element is lower than that of the orange light emitting element. Therefore, in order to set the emitted light from the illuminated member to be approximately the same when the white light emitting element emits light and when the orange light emitting element emits light, the number of the light emitting elements 130 is the same as the number of white light emitting elements. It is necessary to provide more than the number of light emitting elements. For example, when the number of orange light-emitting elements is six, the number of white light-emitting elements needs to be eight, so that when the design specification is changed such that only the light-emitting color of the light-emitting element 130 differs depending on the vehicle model, A dedicated printed wiring board was designed separately for each design specification.

  However, by changing the design specification in which only the emission color of the light emitting element 130 is changed from orange to white, if a printed wiring board is separately designed and dealt with for each design specification, the design work of the printed wiring board is enormous. In addition, a large number of man-hours are required, and management of the printed wiring board becomes troublesome in mass production (mass production) of a device (for example, a display unit having a liquid crystal display panel) on which the printed wiring board is mounted.

  In order to solve this problem, for example, a printed wiring board that can mount six orange light emitting elements or eight white light emitting elements is prepared, and six pieces are provided on the printed wiring board according to the design specifications. Only the orange light-emitting elements are mounted, or only eight white light-emitting elements are mounted and mounted on the printed wiring board according to the design specifications (the orange light-emitting element group and the white light-emitting element group). Control may be performed so that all of one) emit light.

  For example, six orange light emitting elements are connected to the first switch means, eight white light emitting elements are connected to the second switch means, and six light emitting elements are controlled by the control signal from the control means. When the orange light emitting element is mounted, the first switch means is on-controlled, and when eight white light emitting elements are mounted, the second switch means is on-controlled. It has become. In this case, six orange light-emitting elements or eight white light-emitting elements are arranged in a row so as to form a pair of rows on the printed wiring board behind the illuminated member (for example, a liquid crystal display panel). Each is connected to a pair of 14 connected lands provided.

  At this time, in the configuration in which six orange light emitting elements are arranged in a concentrated manner or in the configuration in which eight white light emitting elements are arranged in a concentrated manner, illumination unevenness is likely to occur when the illuminated member is illuminated. Thus, it is necessary to connect each light emitting element to each corresponding connection land in a dispersed state as shown in the mounting state diagram of the light emitting element shown in FIG. 6, for example. There is.

  Here, in FIG. 6, P is a printed wiring board, 131 is an orange light emitting element, 132 is a white light emitting element arranged in parallel with the orange light emitting element 131, and 111 is patterned in a shape capable of mounting the orange light emitting element 131. A negative-side connection land (hereinafter referred to as a first connection land) 112 is a positive-side connection land (hereinafter referred to as a second connection land) patterned in a shape capable of mounting the orange light emitting element 131. It is. Reference numeral 121 denotes a negative-side connection land (hereinafter, referred to as a third connection land) patterned in a shape capable of mounting the white light-emitting element 132, and 122 denotes a pattern formed in a shape capable of mounting the white light-emitting element 132. It is assumed that this is a positive-side connection land (hereinafter referred to as a fourth connection land). In FIG. 6, the white light emitting element 132 that is a dotted line portion is not mounted on the printed wiring board P.

  In such a configuration, for example, the orange light emitting element 131 is connected to the first and second connection lands 111 and 112, and the white light emitting element 132 is not connected to the third and fourth connection lands 121 and 122. The heat generated when the orange light emitting element 131 emits light is introduced into the atmosphere by the first and second connection lands 111 and 112 that are conductively connected to a pair of first terminal portions (not shown) provided in the orange light emitting element 131. Heat is dissipated.

  Conversely, for example, in a state where the orange light emitting element 131 is not connected to the first and second connection lands 111 and 112, and the white light emitting element 132 is connected to the third and fourth connection lands 121 and 122, The heat generated when the white light emitting element 132 emits light is radiated to the atmosphere by the third and fourth connection lands 121 and 122 connected to a pair of second terminal portions (not shown) provided in the white light emitting element 132. Being done.

  That is, when only the orange light emitting element 131 is mounted, heat generated when the orange light emitting element 131 emits light is only in the first and second connection lands 111 and 112 that are conductively connected to the pair of first terminal portions. When only the white light emitting element 132 is mounted, the heat generated when the white light emitting element 132 emits light is electrically connected to the pair of second terminal portions. However, when the orange light emitting element 131 or the white light emitting element 132 is applied as a backlight light source and the liquid crystal display panel is backlit, a sufficient amount of light is obtained. Therefore, it is necessary to pass a large amount of current through the orange light emitting element 131 and the white light emitting element 132.

  If a large amount of current is supplied to the orange light-emitting element 131 or the white light-emitting element 132, naturally, the amount of heat generated when the orange light-emitting element 131 or the white light-emitting element 132 emits light increases. A structure in which heat generated during light emission of the orange light emitting element 131 during mounting is dissipated by the first and second connection lands 111 and 112 connected to the pair of first terminal portions, or a white light emitting element when only the white light emitting element 132 is mounted When the heat generated during the light emission of 132 is radiated by the third and fourth connection lands 121 and 122 connected to the pair of second terminal portions, the amount of heat generated by the orange light-emitting element 131 or the white light-emitting element 132 However, sufficient heat dissipation cannot be performed.

In addition, when the orange light emitting element 131 emits light, the first connection land 111 that is the connection land on the negative electrode side of the orange light emission element 131 has more heat than the second connection land (positive connection land) 112. Similarly, when the white light emitting element 132 emits light, the third connection land 121, which is the negative side connection land of the white light emitting element 132, is the fourth connection land (positive side connection land) 121. Since more heat is more easily transferred, it has been desired to sufficiently dissipate heat particularly in the connection lands (first and third connection lands 111 and 121) on the negative electrode side.
Accordingly, an object of the present invention is to provide a printed wiring board capable of radiating heat generated by a light emitting element satisfactorily in order to cope with the above-described problems.

  In the present invention, the first and second connection lands that can mount the first light emitting element that emits the first light emission color and the second light emitting element that emits the second light emission color can be mounted. , A fourth connection land and a printed wiring board provided in the wiring portion, wherein the first light emitting element is mounted on the first and second connection lands, and the second light emitting element. Is mounted on the third and fourth connection lands, at least one of the first and second connection lands, and the third and third connection lands. One of the four connection lands is connected to the connection land through a conductive portion.

  According to the present invention, the first and second connection lands that can mount the first light emitting element that emits the first light emitting color and the second light emitting element that emits the second light emitting color can be mounted. In the printed wiring board in which the third and fourth connection lands are provided in the wiring portion, the state in which the first light emitting element is mounted on the first and second connection lands, and the second light emission In at least one of a state in which an element is mounted on the third and fourth connection lands, the first connection land, the third connection land, and the second connection land and the The fourth connection lands are connected to each other through a conductive portion.

  ADVANTAGE OF THE INVENTION According to this invention, the printed wiring board which can achieve an initial objective and can thermally radiate the heat | fever which a light emitting element emits favorably can be provided.

  Hereinafter, an embodiment of a printed wiring board according to the present invention will be described based on the accompanying drawings. 1 is a front view of a principal part of the printed wiring board showing a state where the light emitting device according to the present embodiment is mounted, and FIG. 2 shows a control circuit for controlling light emission / non-light emission of the light emitting device according to the present embodiment. FIG. 3 is a block diagram showing an enlarged front view of a printed wiring board showing an A portion in FIG.

  In FIG. 1, a printed wiring board 10 according to the present embodiment includes a plurality of backlight light sources (light emitting elements) 20 for backlighting a liquid crystal display panel (illuminated member) (not shown) mounted on a vehicle meter, for example. Is composed of a circuit board mounted in a row (one row).

In this case, the backlight source 20 emits six orange light-emitting elements (first light-emitting elements) 21 that emit orange light that is the first emission color, and 8 that emits white light that is the second emission color. White light emitting elements (second light emitting elements) 22.
The backlight light source 20 is mounted in a row (one row) on the surface portion 11 of the printed wiring board 10 which is a portion facing the liquid crystal display panel.

  In the case of the present embodiment, the design specification is such that only six orange light emitting elements 21 of the backlight light source 20 are mounted on the surface portion 11, and the eight white light emitting elements 22 are provided on the surface portion. It is assumed that the specification is not implemented in No. 11.

  Further, in another design specification different from the design specification, only eight white light emitting elements 22 (see the dotted line portion in FIG. 1) of the backlight light source 20 are provided in correspondence with the design specification. Needless to say, the six orange light-emitting elements 21 are not mounted on the surface portion 11 at this time. .

  Here, when the six orange light emitting elements 21 (or eight white light emitting elements 22) are mounted on the surface portion 11, each orange light emitting element 21 (or each white light emitting element 21) is provided to uniformly illuminate the liquid crystal display panel. It is necessary to mount the light emitting elements 22) in a dispersed state as shown in FIG. Although not shown in detail, a case body is disposed between the liquid crystal display panel and the printed wiring board 10 so as to surround each orange light emitting element 21 (or each white light emitting element 22), and It is assumed that a diffusion plate is disposed between the case body and the liquid crystal display panel.

  Next, a control circuit for controlling the light emission / non-light emission of the orange light emitting element 21 will be described with reference to FIG. In FIG. 2, a control circuit for controlling light emission / non-light emission of the single orange light emitting element 21 mounted on the printed wiring board 10 (surface portion 11) will be described.

  In the present embodiment, only six orange light emitting elements 21 are applied, and eight white light emitting elements 22 are not applied. Therefore, in FIG. 2, the common circuit portion B <b> 1 indicated by the one-dot chain line is configured so that one orange light emitting element 21 and one white light emitting element 22 can be alternatively mounted. There may be a maximum of 6 sets of circuit parts B1, but these common circuit parts B1 are all commonly connected at the circuit connection part B2 in FIG.

  The control circuit is provided on a single printed wiring board 10, and includes a backlight light source 20, a first switch unit 30, a second switch unit 40, a first limiting resistor 50, and a second limiter. The limiting resistor 60, a pair of first and second connection lands 70 and 71, and a pair of third and fourth connection lands 80 and 81 are provided.

  As described above, the backlight light source 20 includes an orange light emitting element (first light emitting element) 21 including a light emitting diode that emits orange light (first light emitting color), and light emission that emits white light (second light emitting color). In this embodiment, only the orange light emitting element 21 is mounted on the surface portion 11, and the white light emitting element 22 is the surface portion. 11 is a design specification that is not implemented on the board.

  The backlight light source 20 (in this case, the orange light emitting element 21) is mounted on the surface portion 11 of the printed wiring board 10 corresponding to (opposed to) the liquid crystal display panel, and its cathode side is grounded to the ground level. .

  The first switch means 30 is for controlling the light emission of the orange light-emitting element 21 by switching the on / off state in accordance with a control signal from the control means (not shown). The circuit connecting portion B2) is connected, and the other end is connected to the first limiting resistor 50.

  The second switch means 40 is configured to switch an on / off state according to a control signal from the control means when the white light emitting element 22 is mounted on the surface portion 11 in the other design specifications. The white light emitting element 21 is for controlling light emission, and one end side thereof is connected to the power supply 90 (circuit connection part B2), and the other end side is connected to the second limiting resistor 60.

  As the control means, for example, a microcomputer can be applied, and an operation input signal (pulse signal) output from an operation means (operation switch or the like) is connected to a device such as a CAN (Controller Area Network) communication cable or an ignition switch. Based on this operation input signal, a control signal for controlling the on / off state of one of the first switch means 30 and the second switch means 40 is generated, and the first switch means 30 or the first switch means 30 The second switch means 40 is controlled to be turned on / off.

  The control means includes a CPU for performing arithmetic processing based on the operation input signal, a readable / rewritable RAM for temporarily storing arithmetic processing results and the like in the CPU, and a ROM for storing a control program and the like. A storage unit configured, and an input / output interface connected by a bus for exchanging the input signal, the control signal, and the like.

  The first limiting resistor 50 is composed of a resistor element such as a chip resistor for adjusting (setting) the current value supplied to the orange light emitting element 21, one end side of which is connected to the first switch means 30, and the other end side thereof. It is connected to the anode side of the orange light emitting element 21.

  The second limiting resistor 60 is a chip resistor for adjusting (setting) a current value supplied to the white light emitting element 22 when the white light emitting element 22 is mounted on the surface portion 11 in the other design specifications. The other end side is connected to the anode side of the white light emitting element 22 and the other end side is connected to the second switch means 40.

  The first and second connection lands 70 and 71 are formed of a pair of lands that are pattern-printed in a shape that allows the orange light emitting element 21 to be mounted (see FIG. 3). Among these, the first connection land 70 has a substantially rectangular shape and corresponds to the connection land on the negative electrode side (ground line side) in the orange light emitting element 21, and the second connection land 71 has a substantially rectangular shape. Thus, it corresponds to the connection land on the positive electrode side (power supply 90 side) in the orange light emitting element 21.

  The third and fourth connection lands 80 and 81 are pattern-printed in a shape that allows the white light emitting element 22 to be mounted when the white light emitting element 22 is mounted on the surface portion 11 in the other design specifications. The lands form a pair and are arranged in parallel so as to form a pair with the first and second connection lands 70 and 71 (see FIG. 3).

  Of the third and fourth connection lands 80 and 81, the third connection land 80 has a substantially rectangular shape, and the white light emitting element 22 is mounted on the surface portion 11 in the other design specifications. In this case, it corresponds to the connection land on the negative electrode side (ground line side) in the white light emitting element 22, and the fourth connection land 81 has a substantially rectangular shape, and in the other design specifications, the surface portion 11 is white. When the light emitting element 22 is mounted, it corresponds to the connection land on the positive electrode side (power supply 90 side) in the white light emitting element 22.

  In the present embodiment, both are connection lands on the negative electrode side, and the first connection land 70 and the third connection land 80 arranged in parallel are connected through the conduction portion C1. In the case of the present embodiment, the conduction portion C1 thermally and electrically connects both the connection lands 70 and 80 so as to completely fill the gap portion existing between the first connection land 70 and the third connection land 80. It consists of a substantially rectangular conductive pattern for connection.

  According to this configuration, when the operation input signal is input to the control unit, the control unit outputs the control signal that turns on the first switch unit 30. The first switch means 30 receives this control signal, switches the first switch means 30 to the on state, and causes the orange light emitting element 21 to emit light, so that the liquid crystal display panel is backlit substantially uniformly. .

  The heat generated when the orange light emitting element 21 emits light is transmitted to the first and second connection lands 70 and 71 connected to the first terminal portion (not shown) provided in the orange light emitting element 21. However, of the first and second connection lands 70 and 71, the first connection land 70, which is the negative-side connection land, heats more than the second connection land 71, which is the positive-side connection land. Is transmitted.

  By the way, in this embodiment, when the orange light emitting element 21 emits light when the first light emitting element 21 is mounted on the first and second connection lands 70 and 71, the orange light emitting element 21 emits light. Accordingly, the first connection land 70 to which more heat is transmitted is electrically and electrically connected to the third connection land 80 through the conduction portion C1. Accordingly, in the present invention, more heat transferred to the first connection land 70 is radiated to the atmosphere only by the first connection land in the prior art. Since heat is dissipated into the atmosphere through a heat dissipation area having a larger surface area formed by the portion C1 and the third connection land 80, it is possible to dissipate heat generated by the orange light emitting element 21 satisfactorily. A printed wiring board can be provided.

  In the present embodiment, an example in which the conductive portion C1 is formed in a substantially rectangular shape so as to fill a gap portion formed between the first connection land 70 and the third connection land 80 has been described. As long as the first and third connection lands 70 and 80 can be connected to each other, the conductive portion C1 can have any shape, and the first and third connection lands 70 and 80 can be used. Needless to say, it is preferable to set the surface area of the heat radiation region formed by the conductive portion C1 to be larger.

  In the present embodiment, the example in which the conduction portion C1 is provided between the first connection land 70 and the third connection land 80 has been described. For example, the conduction portion C1 is connected to the second connection land 71 and the fourth connection land C4. Provided between the first and second connection lands 81, or when the two connection lands 71 and 81 are connected to each other, or the conductive portion C1 is connected between the first and third connection lands 70 and 80 and the second and fourth connection lands. Needless to say, even if it is provided between 71 and 81, the same effect as the effect described in the present embodiment can be obtained. In particular, when the conduction portions C1 are provided in the connection lands 70 and 80 and the connection lands 71 and 81, the heat generated by the orange light emitting element 21 can be radiated more effectively.

  In the present embodiment, the state in which the first light emitting element 21 is mounted on the first and second connection lands 70 and 71 has been described. For example, in the case of the other design specifications, the orange light emitting element 21 is used. Even if the white light emitting element 22 is mounted on the third and fourth connection lands 80 and 81 instead of the first connection land 70 and the third connection land 80, It goes without saying that the heat generated by the white light emitting element 22 can be dissipated if the conduction portion C1 is provided in at least one of the connection land 71 and the fourth connection land 81.

  In the present embodiment, the case where the orange light emitting elements 21 (or the white light emitting elements 22) are mounted on the printed wiring board 10 is described. However, for example, the orange light emitting elements 21 can be mounted as shown in FIG. The arrangement positions of the first and second connection lands 70 and 71 in FIG. 4 are slightly different from the arrangement positions of the third and fourth connection lands 80 and 81 that enable the white light emitting element 22 to be mounted. Even if the first connection land 70 and the fourth connection land 81 are connected by connecting the first connection land 70 and the fourth connection land 81, the conductive portion C 1 is provided between the first connection land 70 and the fourth connection land 81. Good. Although not shown in detail, the white light emitting element 22 can be mounted at the positions where the first and second connection lands 70 and 71 capable of mounting the orange light emitting element 21 can be mounted, contrary to the above-described configuration. The third and fourth connection lands 80 and 81 are set slightly below the opposite side to the upper side of the arrangement position of the second connection land 71 and the third connection land 80. The second connection land 71 and the third connection land 80 may be connected by providing a conduction portion C1 therebetween.

  In the present embodiment, the orange light emitting element 21 emits light in a state where only the orange light emitting element 21 is mounted on the printed wiring board 10, or only the white light emitting element 22 is mounted on the printed wiring board 10. The configuration in which the white light emitting element 22 emits light in the state has been described. For example, in a state in which the orange light emitting element 21 and the white light emitting element 22 are mounted on the printed wiring board 10, both the light emitting elements 21 and 22 emit light. Also good.

  In this case, the ground terminal connected to the second switch means 40, the second limiting resistor 60, and the third connection land 80 in the control circuit (particularly the common circuit section B1) of the light emitting element shown in FIG. And the third and fourth connection lands 80 and 81 need to be connected in parallel to the first and second connection lands 70 and 71.

  Even in such a configuration, one of the first and second connection lands 70 and 71 and one of the third and fourth connection lands 80 and 81 are electrically connected. By adopting a configuration that is connected through the part C1, the heat radiation efficiency can be improved by the amount of provision of the conduction part C1. Further, if the first connection land 70 and the third connection land 80, and the second connection land 71 and the fourth connection land 81 are connected through the conduction part C1, the two conduction parts C1 are provided. The heat radiation efficiency can be improved by the amount provided.

It is a principal part front view of the printed wiring board which shows the state in which the light emitting element by this embodiment was mounted. FIG. 3 is a block diagram showing a control circuit for controlling light emission / non-light emission of the light emitting element according to the embodiment. It is an enlarged front view of the printed wiring board which expands and shows the A section in FIG. It is an enlarged front view of the printed wiring board by the modification of this invention. It is a principal part front view of the printed wiring board by a prior art. It is a principal part front view of the printed wiring board which shows the state in which the light emitting element by a prior art was mounted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printed wiring board 11 Surface part 20 Backlight light source (light emitting element)
21 1st light emitting element (orange light emitting element)
22 2nd light emitting element (white light emitting element)
30 1st switch means 40 2nd switch means 50 1st limiting resistance 60 2nd limiting resistance 70 1st connection land 71 2nd connection land 80 3rd connection land 81 4th connection land 90 Power supply B1 common circuit part B2 circuit connection part C1 conduction part

Claims (2)

First and second connection lands capable of mounting a first light emitting element emitting a first emission color;
In the printed wiring board in which the third and fourth connection lands that can mount the second light emitting element that emits the second emission color are provided in the wiring portion,
At least one of a state where the first light emitting element is mounted on the first and second connection lands and a state where the second light emitting element is mounted on the third and fourth connection lands. In one state
One of the first and second connection lands is connected to one of the third and fourth connection lands through a conductive portion. Printed wiring board. First and second connection lands capable of mounting a first light emitting element emitting a first emission color;
In the printed wiring board in which the third and fourth connection lands that can mount the second light emitting element that emits the second emission color are provided in the wiring portion,
At least one of a state where the first light emitting element is mounted on the first and second connection lands and a state where the second light emitting element is mounted on the third and fourth connection lands. In one state
The printed wiring board, wherein the first connection land and the third connection land, and the second connection land and the fourth connection land are connected through a conductive portion.

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