JP5049148B2 - Semiconductor light emitting module and image reading apparatus using the same - Google Patents

Description

  The present invention relates to a semiconductor light emitting module on which an LED chip that emits red light, green light, and blue light, for example, and an image reading apparatus using the same.

  FIG. 8 shows a conventional semiconductor light emitting module X. The semiconductor light emitting module X shown in the figure includes a lead 91, three LED chips 92, and a resin package 93. The lead 91 is for supplying power to the LED chip 92, and includes a die bonding pad 91a, a wire bonding pad 91b, and a terminal 91c. The die bonding pad 91a is composed of three lands. An LED chip 92 is die bonded to each land. The three LED chips 92 are configured to emit red light, green light, and blue light. Each LED chip 92 is connected to a wire bonding pad 91b by a wire. The terminal 91c is used for connecting the semiconductor light emitting module X to a circuit board or the like and mounting it on the image reading apparatus. The resin package 93 is made of, for example, a white resin and partially covers the leads 91. An opening 93 a is formed in the resin package 93. The opening 93a exposes the three LED chips 92.

  When the semiconductor light emitting module X is used in an image reading device (not shown), a light guide (not shown) is disposed in front of the semiconductor light emitting module X. This light guide is in the shape of a long and narrow bar, and its one end faces the three LED chips 92. The light incident from the end face is appropriately reflected in the width direction of the light guide while traveling in the longitudinal direction of the light guide. And the linear light extended in the longitudinal direction is emitted from the said light guide. This linear light is applied to a document or the like that is an object to be read. The reflected light is received by, for example, a sensor IC chip (not shown), so that the contents described on the original can be read as image data.

  However, in order to obtain clear image data, the linear light needs to be irradiated to the original with uniform and high luminance. As a countermeasure, the arrangement of the three LED chips 92 may be variously changed. When such a change is made, it is forced to change the shape and arrangement of the die bonding pad 91a. As a result, there is a disadvantage that the costs of the semiconductor light emitting module and the image reading device increase.

JP 2007-78916 A

  The present invention has been conceived under the above circumstances, and it is an object of the present invention to provide a semiconductor light emitting module capable of changing the arrangement of semiconductor light emitting elements and an image reading apparatus using the same. And

  A semiconductor light emitting module provided by a first aspect of the present invention is a semiconductor light emitting module comprising a conductive support member having a die bonding pad and a plurality of semiconductor light emitting elements die bonded to the die bonding pad. The plurality of semiconductor light emitting elements are arranged in series along a first direction, and the die bonding pad is arranged with respect to a symmetry axis extending in a second direction that is different from the first direction. The semiconductor light-emitting device has a portion overlapping a virtual die bonding position that is axisymmetric to the die bonding position of the semiconductor light emitting device.

  According to such a configuration, the plurality of semiconductor light emitting elements can be arranged at two positions that are line-symmetric with respect to the symmetry axis. Accordingly, even if there is a change in, for example, the configuration of the image reading apparatus in which the semiconductor light emitting module is used, it is possible to cope with the change without redesigning the die bonding pad. Therefore, an increase in cost of the semiconductor light emitting module can be avoided.

  In a preferred embodiment of the present invention, the die bonding pad has a plurality of lands in which the plurality of semiconductor light emitting elements are individually die bonded, and the plurality of lands are the plurality of semiconductor light emitting elements. That has an arc shape centering on the intersection of the array axis and the symmetry axis, or that has a portion overlapping the intersection. According to such a configuration, the plurality of semiconductor light emitting elements are arranged along an array axis extending in any direction sandwiched between the array axis and an array axis having a line-symmetric relationship with the array axis. be able to.

  In a preferred embodiment of the present invention, the conduction support member includes a lead for constituting the die bonding pad, and the lead extends from at least one of the plurality of lands, and the lead It has the extension part which is not connected with respect to other parts. According to such a structure, when manufacturing the said semiconductor light-emitting module, it can prevent that the said land becomes unstable by supporting the said extension part.

  In a preferred embodiment of the present invention, the die bonding pad includes one land that overlaps all of the die bonding positions of the plurality of semiconductor light emitting elements and the plurality of virtual die bonding positions. According to such a configuration, the plurality of semiconductor light emitting elements can be brought close to each other. This is advantageous for emitting clear white light, for example, by promoting the mixing of red light, green light, and blue light.

  An image reading apparatus provided by the second aspect of the present invention is in the form of an elongated rod made of a light-transmitting material and one or more semiconductor light-emitting modules provided by the first aspect of the present invention. A light guide including an incident surface located in front of the module, a reflective surface extending in the longitudinal direction, and an exit surface extending in the longitudinal direction and located on the opposite side of the reflective surface; and light reflected from the reading object And a light receiving means for receiving light.

  In a preferred embodiment of the present invention, the light guide has two incident surfaces on both ends, and includes the two semiconductor light emitting modules facing the two incident surfaces. According to such a configuration, it is possible to increase the luminance of the linear light emitted from the image reading device and make the luminance distribution uniform.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 and 2 show a first embodiment of a semiconductor light emitting module according to the present invention. The semiconductor light emitting module A1 of this embodiment includes a conduction support member 1, LED chips 2R, 2G, 2B, and wires 3. The semiconductor light emitting module A1 is used as a light source of an image reading device, for example, as will be described later.

  The conduction support member 1 conducts the LED chips 2R, 2G, and 2B to an external electric circuit (not shown) and has a function of supporting them. In the present embodiment, the conduction support member 1 includes a lead 1A and a resin package 1B.

  The lead 1A is made of an alloy such as Cu or Ni, for example, and includes a die bonding pad 11, an extending portion 12, a wire bonding pad 13, and a plurality of terminals 14. The die bonding pad 11 is a portion for die bonding the three LED chips 2R, 2G, and 2B, and includes three lands 11a, 11b, and 11c. The land 11b has a substantially circular shape and is located at the approximate center of the semiconductor light emitting module A1. The lands 11a and 11c are arranged with the land 11b interposed therebetween. Each of the lands 11a and 11c has a substantially arc shape. These shapes are concentric circles centering on an intersection of array axes L1 and L2 and a symmetry axis S described later. The extending portion 12 extends from the land 11 b and the tip thereof is not connected to any of the lands 11 a and 11 c and the wire bonding pad 13.

  The wire bonding pad 13 has a C shape surrounding the die bonding pad 11. One end of three wires 3 is bonded to the wire bonding pad 13. The other ends of these wires 3 are bonded to the LED chips 2R, 2G, 2B. The plurality of terminals 14 extend in parallel with each other from the resin package 1B, and are used to connect the semiconductor light emitting module A1 to a circuit board or the like.

  The resin package 1B is made of, for example, white resin and partially covers the leads 1A. The resin package 1B has sides 15 and 16 that are perpendicular to each other. A hood 17 is formed on the resin package 1B. The hood 17 is used, for example, for aligning the light guide 4 of the image reading apparatus B described later. Inside the hood 17 is an opening exposing the three LED chips 2R, 2G, 2B and the die bonding pad 11.

  The LED chips 2R, 2G, and 2B include, for example, an active layer and an n-type semiconductor layer and a p-type semiconductor layer sandwiching the active layer, and are configured to emit red light, green light, and blue light. The LED chips 2R, 2G, and 2B of this embodiment are of a so-called one-wire type, and have a cathode formed on the bottom surface and an anode formed on the top surface. The LED chip 2R is die-bonded to the land 11a, the LED chip 2G is die-bonded to the land 11b, and the LED chip 2B is die-bonded to the land 11c. The cathode is electrically connected to the die bonding pad 11. A wire 3 is bonded to the anode. As shown in FIG. 1, the LED chips 2R, 2G, and 2B are arranged in series along the arrangement axis L1.

  In the present embodiment, the array axis L1 is inclined about 45 degrees with respect to both the sides 15 and 16. The array axis L2 is an axis that is in a line-symmetric relationship with the array axis L1 with respect to the symmetry axis S. The symmetry axis S extends parallel to the side 15. The virtual die bonding positions 2R 'and 2B' have a line-symmetric relationship with the LED chips 2R and 2B with respect to the symmetry axis S, and are located on the array axis L2. Since the LED chip 2G is located on the symmetry axis S, the LED chip 2G itself can be a virtual die bonding position that is line-symmetric with respect to the symmetry axis S. As is well understood from FIG. 1, the land 11a overlaps both the die bonding position and the virtual die bonding position 2R 'of the LED chip 2R. Similarly, the land 11c overlaps with both the die bonding position and the virtual die bonding position 2B 'of the LED chip 2B. The direction in which the arrangement axis L1 extends corresponds to the first direction in the present invention, and the direction in which the symmetry axis S extends corresponds to the second direction in the present invention.

  3 to 5 show an example of an image reading apparatus according to the present invention. The image reading apparatus B of the present embodiment has two semiconductor light emitting modules A1, and in addition, includes a light guide 4, a lens unit 5, a plurality of sensor IC chips 6, a substrate 7, and a case 8. ing. As shown in FIGS. 4 and 5, the image reading apparatus B has a function of reading the contents described in the document Dc as image data by irradiating the document Dc placed on the document table St, for example, with linear light. Have

  The light guide 4 is a highly transparent member made of an acrylic resin such as PMMA (polymethyl methacrylate), and has a circular cross section in the present embodiment. The light guide 4 has two incident surfaces 41, a reflecting surface 42, and an emitting surface 43. The incident surfaces 41 are provided at both ends of the light guide 4. Both ends of the light guide 4 are fitted into the hoods 17 of the two semiconductor light emitting modules A1. As a result, each incident surface 41 faces the semiconductor light emitting module A1.

  4 is a cross-sectional view of the semiconductor light emitting module A1 located on the left side in FIG. As shown in the figure, the arrangement axis L1 coincides with the direction from the reflection surface 42 toward the emission surface 43. That is, the LED chips 2R, 2G, 2B arranged in series along the arrangement axis L1 are arranged along the direction from the reflecting surface 42 to the emitting surface 43.

  On the other hand, FIG. 5 is a cross-sectional view of the semiconductor light emitting module A1 located on the right side in FIG. In this figure, the arrangement axis L2 coincides with the direction from the reflection surface 42 toward the emission surface 43. The semiconductor light emitting module A1 shown in this figure is different from the semiconductor light emitting module A1 shown in FIG. 4 in that LED chips 2R, 2G, and 2B are arranged in series along the array axis L2. Such a semiconductor light emitting module A1 is manufactured by die bonding the LED chips 2R and 2B to the virtual die bonding positions 2R 'and 2B' in FIG.

  The reflecting surface 42 is a surface for reflecting the light traveling from the incident surface 41 along the longitudinal direction of the light guide 4 toward the emitting surface 43. In the reflecting surface 42, for example, a plurality of grooves are formed. The emission surface 43 is a surface that emits light toward the document Dc, and extends in the longitudinal direction. From the emission surface 43, linear light extending in the longitudinal direction is emitted.

  The lens unit 5 is for converging the light reflected by the document Dc onto the plurality of sensor IC chips 6 at the same erect magnification. The plurality of sensor IC chips 6 are semiconductor chips each having a light receiving portion (not shown), and are mounted on the substrate 7. The sensor IC chip 6 has a photoelectric conversion function and is configured to output an image signal having an output level corresponding to the amount of received light. The substrate 7 is made of, for example, ceramic such as alumina or aluminum nitride, or glass epoxy resin, and has a long rectangular shape. The substrate 7 is attached to the lower end of the case 8 and positioned with respect to the case 8. The case 8 is made of synthetic resin and accommodates the substrate 7, the semiconductor light emitting module A 1, the sensor IC chip 6, the light guide 4, and the lens unit 5.

  Next, operations of the semiconductor light emitting module A1 and the image reading device B will be described.

  According to the present embodiment, the LED chips 2R, 2G, and 2B can be arranged along at least one of the arrangement axes L1 and L2. Therefore, for example, even when two semiconductor light emitting modules A1 are provided at both ends of the light guide 4 of the image reading apparatus B, there is no need to make the leads 1A separately. Therefore, it is possible to avoid an increase in cost of the semiconductor light emitting module A1 and further the image reading apparatus B.

  Since the lands 11a and 11c are concentric, the LED chips 2R and 2B can be arranged along another arrangement axis that may exist between the arrangement axes L1 and L2. Therefore, by appropriately setting the axis on which the LED chips 2R and 2B are arranged between the arrangement axis L1 and the arrangement axis L2, for example, in the image reading apparatus B, the portion where the document Dc is illuminated by the linear light is determined. Fine adjustments can be made.

  In the manufacturing process of the semiconductor light emitting module A1, when forming the resin package 1B, generally, molding using a mold is performed. In this molding, the land 11b extending in a branch shape tends to be unstable. The resin package 1B can be formed in a state where the land 11b is stabilized by molding the extension portion 12 in a state where the extension portion 12 is pressed against a part of the mold with pins or the like. When pressed by the pin, the resin does not wrap around the back side of the extended portion 12, and becomes slightly unstable compared to the land 11b or the like where the resin wraps around. However, since the extending portion 12 is not a portion where the LED chips 2R, 2G, and 2B are die-bonded or the wire 3 is bonded, there is little possibility that the bonding operation becomes unstable.

  The image reading apparatus B is configured such that light from the two semiconductor light emitting modules A1 enters from both sides of the light guide 4. Thereby, while improving the brightness | luminance of the linear light radiate | emitted from the light guide 4, the luminance distribution in a longitudinal direction can be equalize | homogenized.

  FIG. 6 shows a second embodiment of the semiconductor light emitting module according to the present invention. The semiconductor light emitting module A2 of the present embodiment is different from the above-described embodiment in the configuration of the die bonding pad 11. In the figure, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment.

  In the present embodiment, the die bonding pad 11 is constituted by one land 11a. The land 11a has a substantially rectangular shape and overlaps all of the die bonding positions of the LED chips 2R, 2G, and 2B and the virtual die bonding positions 2R 'and 2B'. All of the LED chips 2R, 2G, and 2B are die-bonded to the land 11a. Three wire bonding pads 13 are arranged around the land 11a. Wires 3 are bonded to these wire bonding pads 13, respectively.

  Also in such an embodiment, the LED chips 2R, 2G, and 2B can be appropriately arranged along the arrangement axes L1 and L2. Therefore, it is possible to avoid an increase in cost of the semiconductor light emitting module A2 and, for example, an image reading apparatus using the same. Furthermore, in this embodiment, the LED chips 2R, 2G, and 2B can be made relatively close to each other. This is suitable for appropriately mixing light from the LED chips 2R, 2G, and 2B, and is preferable for emitting clear white light.

  FIG. 7 shows a third embodiment of the semiconductor light emitting module according to the present invention. The semiconductor light emitting module A3 of the present embodiment is different from the above-described embodiments in the configuration of the LED chips 2R, 2G, and 2B. In the figure, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment.

  In the present embodiment, the die bonding pad 11 is constituted by one land 11a. As shown in FIG. 7, all of the LED chips 2R, 2G, and 2B are die-bonded in series along the arrangement axis L1 on the land 11a. The land 11a has a substantially rectangular shape and overlaps all of the die bonding positions of the LED chips 2R, 2G, and 2B and the virtual die bonding positions 2R 'and 2B'.

  The LED chips 2R, 2G, and 2B are of a so-called two-wire type, and a cathode and an anode are formed on the upper surface. Different wires 3 are bonded to the cathode and the anode, respectively. Three wires 3 are bonded to the die bonding pad 11. The anode and the die bonding pad 11 are electrically connected by the wire 3. On the other hand, around the land 11a, three wire bonding pads 13 are arranged. Wires 3 are bonded to these wire bonding pads 13, respectively. The cathode and the wire bonding pad 13 are electrically connected to each other by the wire 3. Also by such embodiment, the effect similar to the above can be acquired.

  The semiconductor light emitting module and the image reading apparatus according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the semiconductor light emitting module and the image reading apparatus according to the present invention can be varied in design in various ways.

  The conduction support member referred to in the present invention is not limited to the one composed of the lead 1A and the resin package 1B. For example, you may comprise a conduction | electrical_connection support member with the board | substrate which consists of an insulating material, and the wiring pattern formed in this. In this case, the die bonding pad referred to in the present invention and the land constituting the same are formed by the wiring pattern. In addition, the semiconductor light emitting device referred to in the present invention is not limited to those emitting red light, blue light, and green light, and other devices emitting light of any wavelength such as visible light, infrared light, and ultraviolet light are used depending on the purpose. Use it. The image reading device B is not limited to the one including the two semiconductor light emitting modules A1 as in the above-described embodiment, and may be configured to include the semiconductor light emitting module A1 only on one side of the light guide 4. Further, the semiconductor light emitting modules A2 and A3 may be used instead of the semiconductor light emitting module A1.

1 is a front view showing a first embodiment of a semiconductor light emitting module according to the present invention. It is sectional drawing which follows the II-II line | wire of FIG. 1 is a cross-sectional view of a main part showing an example of an image reading apparatus according to the present invention. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing which follows the VV line of FIG. It is a front view which shows 2nd Embodiment of the semiconductor light-emitting module which concerns on this invention. It is a front view which shows 3rd Embodiment of the semiconductor light-emitting module which concerns on this invention. It is a front view which shows an example of the conventional semiconductor light-emitting module.

Explanation of symbols

A1, A2, A3 Semiconductor light emitting module B Image reader L1, L2 Arrangement axis S Symmetry axis 1 Conductive support member 1A Lead 1B Resin package 11 Die bonding pads 11a, 11b, 11c Land 12 Extension part 13 Wire bonding pad 14 Terminal 15 16 Side 17 Hood 2R, 2G, 2B LED chip (semiconductor light emitting device)
2R ′, 2B ′ Virtual die bonding position 3 Wire 4 Light guide 41 Incident surface 42 Reflecting surface 43 Output surface 5 Lens unit 6 Sensor IC chip (light receiving means)
7 Substrate

Claims (6)

A conduction support member having a die bonding pad;
A plurality of semiconductor light emitting devices die bonded to the die bonding pad;
A semiconductor light emitting module comprising:
The plurality of semiconductor light emitting elements are arranged in series along the first direction,
The die bonding pad has a portion that overlaps a virtual die bonding position that is axisymmetric with a die bonding position of the plurality of semiconductor light emitting elements with respect to a symmetry axis extending in a second direction that is different from the first direction. A semiconductor light emitting module characterized by comprising: The die bonding pad has a plurality of lands in which the plurality of semiconductor light emitting elements are individually die bonded,
The plurality of lands are those having an arc shape centering on an intersection of the array axis of the plurality of semiconductor light emitting elements and the symmetry axis, or having a portion overlapping the intersection. The semiconductor light emitting module as described. The conduction support member includes a lead for constituting the die bonding pad,
3. The semiconductor according to claim 2, wherein the lead has an extending portion that extends from at least one of the plurality of lands and is not connected to another portion of the lead. Light emitting module.   2. The semiconductor light emitting module according to claim 1, wherein the die bonding pad includes one land that overlaps all of the die bonding positions of the plurality of semiconductor light emitting elements and the plurality of virtual die bonding positions. One or more semiconductor light emitting modules according to claim 1,
An elongated bar made of a light-transmitting material has an incident surface located in front of the semiconductor light emitting module, a reflecting surface extending in the longitudinal direction, and an emitting surface extending in the longitudinal direction and located on the opposite side of the reflecting surface. A light guide comprising:
An image reading apparatus comprising: a light receiving unit configured to receive light reflected from an object to be read. The light guide has two incident surfaces on both ends,
The image reading apparatus according to claim 5, comprising two semiconductor light emitting modules facing the two incident surfaces.

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