JP5505096B2 - Light source device - Google Patents

Description

  The present invention relates to a light source device for reading a document used in devices such as a facsimile, a copying machine, and a scanner.

Equipment such as facsimiles, copiers, and scanners have a document reading device that reads text and image information on the document surface by reflected light from the document surface, and this document reading device is equipped with a light source device that illuminates the document surface. Has been.
As such a light source device, one in which a light emitting diode is arranged on one end face of a rod-shaped light guide is known (see Patent Document 1).

FIG. 7 is an explanatory cross-sectional view showing a configuration of a main part in an example of a conventional light source device. This light source device has a rod-shaped light guide 70 made of a translucent resin such as acrylic resin, and the light guide 70 emits light whose outer peripheral contour in a cross section perpendicular to the longitudinal direction is an arc. A surface 71 is formed along the longitudinal direction of the light guide 70, and a small prism group 72 is formed on the peripheral surface facing the light emitting surface 71.
A light emitting diode 85 is disposed at one end of the light guide 70 so as to face the one end surface 75 of the light guide 70. Specifically, a power supply wiring board 80 having a wiring (not shown) formed on the surface thereof is disposed so as to face one end surface 75 of the light guide 70, and the electrostatic protection is provided on the surface of the power supply wiring board 80. A light emitting diode 85 is arranged through the diode element 81. The diode element 81 is electrically connected to the power supply wiring board 80 by the conductive adhesive 82 and the wire wiring 83, while the light emitting diode 85 is electrically connected to the diode element 81 by the micro bump 86. A hemispherical sealing body 87 made of a translucent resin is provided so as to cover the entire diode element 81 and the light emitting diode 85.
Further, on the surface of the power supply wiring board 80, a cylindrical light reflection member 90 having a light reflection surface 91 whose diameter increases from the power supply wiring board 80 toward the light guide 70 on the inner peripheral surface is the light reflection surface. 91 is arranged so as to surround the optical path between the light emitting diode 85 and the light guide 70. The light reflecting member 90 is made of a resin material having electrical insulation that is colored in white so that a short circuit does not occur between the wirings even if the light reflecting member 90 contacts the wirings formed on the surface of the power supply wiring board 80. .

  In such a light source device, the light emitted from the light emitting diode 85 is reflected directly or through the light reflecting surface 91 of the light reflecting member 90 via the optical path between the light emitting diode 85 and the light guide 70. The light enters the light guide 70 from one end surface 75 of the light guide 70, and the incident light is guided in the longitudinal direction of the light guide 70 while being reflected by the light guide 70 on the peripheral surface thereof. The reflected light is reflected by the prism group 72 toward the light emitting surface 71, and the reflected light is emitted from the light emitting surface 71 of the light guide 70, and is applied to, for example, the document surface of the document placed on the document table.

  Thus, a light source device mounted on a document reading device is required to have higher illuminance on the document surface. In order to achieve such a light source device with higher illuminance, a light guide device is required. It is necessary to increase the amount of light incident on one end surface of the body, specifically, to use a light-emitting diode with high output or to use a plurality of light-emitting diodes.

Japanese Patent Laid-Open No. 11-84137

However, in the above light source device, when the amount of light incident on one end surface of the light guide 70 is increased, the light reflecting member 90 that surrounds the optical path between the light emitting diode 85 and the light guide 70 is provided. Since the constituent resin has a low heat dissipation property, one end portion of the light guide body 70 is heated to a considerably high temperature, and as a result, the one end portion of the light guide body 70 may be thermally deformed. There is.
Further, when the light reflecting member 90 is made of a metal having high heat dissipation, there is a possibility that a short circuit may occur between the wirings formed on the surface of the power supply wiring board 80.

  The present invention has been made based on the circumstances as described above, and the object thereof is one end of the light guide even when the amount of light incident on one end surface of the light guide is increased. An object of the present invention is to provide a light source device that can suppress the heating of the part to a high temperature and that does not cause a short circuit between the wirings formed on the surface of the power supply wiring board via the light reflecting member. .

The light source device of the present invention includes a rod-shaped light guide,
An LED which is composed of a circuit board, a light emitting diode disposed on the surface of the circuit board, and a light-transmitting sealing body provided so as to cover the light emitting diode, and is disposed so as to face one end surface of the light guide body An implementation,
A power supply wiring board disposed on the back surface of the circuit board in this LED mounting body and electrically connected to the LED mounting body, and having wiring on the surface,
A cylindrical light reflecting surface forming portion having an inner peripheral surface formed with a light reflecting surface whose diameter increases toward the tip from the proximal end positioned close to the power supply wiring board , and the tip of the light reflecting surface forming portion. A cylindrical light guide receiving portion that extends continuously in the longitudinal direction of the light guide, and one end of the light guide is inserted into the light guide receiving portion, and the light reflecting surface Comprising a metal light reflecting member arranged so as to surround an optical path between the LED mounting body and the light guide body,
The light reflecting member has a plurality of projecting leg portions that project from the base end face of the light reflecting surface forming portion toward the power supply wiring board and come into contact with non-wiring regions on the surface of the power supply wiring board. The base end surface of the reflection surface forming portion is disposed so as to be separated from the surface of the circuit board.

In the light source device of the present invention, it is preferable that a light-shielding body that shields light traveling toward a gap between the surface of the power supply wiring board and the base end surface of the light reflecting surface forming portion is provided.
Further, between the circuit board and the light reflecting surface forming portion, the periphery of the sealing body is surrounded, and the back surface located close to the circuit substrate is located close to the light reflecting surface forming portion. It is preferable that an insulating light reflecting member made of an electrically insulating material having a light reflecting surface whose diameter increases toward the surface is provided.
Moreover, it is preferable that the said electric power feeding wiring board is formed by wiring on a metal plate through an insulating layer.

According to the light source device of the present invention, since the light reflecting member is made of a metal with high heat dissipation, even when the amount of light incident on one end surface of the light guide is increased, Since it is suppressed that one end part is heated to high temperature, it can prevent that a heat deformation arises in the one end part of the said light guide. Moreover, the light reflecting member has a plurality of projecting leg portions that protrude from the base end surface of the light reflecting surface forming portion toward the power supply wiring board and come into contact with the non-wiring region on the surface of the power supply wiring board. Since the base end face of the light reflecting surface forming part is separated from the surface of the circuit board, between the wires formed on the surface of the power supply wiring board via the light reflecting member and on the surface of the circuit board in the LED mounting body There is no short circuit between the formed wires.
In addition, according to the configuration in which the light shielding body that shields the light toward the gap between the surface of the power supply wiring board and the base end surface of the light reflection surface forming portion in the light reflecting member is provided, the light reflection surface forming portion and the power supply wiring are provided. Generation of stray light due to light being emitted from between the surfaces of the plates can be prevented.
Further, between the circuit board in the LED mounting body and the light reflecting surface forming portion in the light reflecting member, the light reflecting surface is surrounded from the sealing body in the LED mounting body and is located close to the circuit board. According to the configuration in which the insulating light reflecting member having the light reflecting surface whose diameter is increased toward the surface located close to the surface forming portion, the surface of the power supply wiring board and the light reflecting surface forming portion in the light reflecting member are provided. Since the light which goes to the gap between the base end face is reflected by the insulating light reflecting member and is incident on the one end face of the light guide, a high light utilization rate can be obtained.

It is sectional drawing for description which shows the structure of the principal part in the light source device which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the light reflection member in the light source device shown in FIG. 1, (a) is a top view, (b) is a side view. It is sectional drawing for description which shows the structure of the principal part in the light source device which concerns on the 2nd Embodiment of this invention. It is sectional drawing for description which shows the structure of the principal part in the light source device which concerns on the 3rd Embodiment of this invention. It is sectional drawing for description which expands and shows a part of light source device shown in FIG. It is explanatory drawing which shows the modification of the protrusion leg part in a light reflection member. It is sectional drawing for description which shows the structure of the principal part in an example of the conventional light source device.

Hereinafter, embodiments of the light source device of the present invention will be described.
FIG. 1 is an explanatory cross-sectional view showing a configuration of a main part of the light source device according to the first embodiment of the present invention. The light source device has a rod-shaped light guide 10 made of a light-transmitting resin such as acrylic resin. In the light guide 10, a light emitting surface 11 having an arcuate outer peripheral contour in a cross section perpendicular to the longitudinal direction is formed along the longitudinal direction of the light guide 10 and faces the light emitting surface 11. A small prism group 12 is formed on the peripheral surface.
The light guide 10 is supported on a base 30 made of a metal having rigidity such as aluminum extending along the longitudinal direction of the light guide 10 directly or via an appropriate support.

  At one end of the light guide 10, the LED mounting body 15 is disposed so as to face the one end surface 13 of the light guide 10. The LED mounting body 15 includes a circuit board 16 disposed so as to face the one end surface 13 of the light guide 10, and a light emitting diode 17 is electrically connected to the circuit board 16 on the surface of the circuit board 16. A hemispherical sealing body 18 made of a heat-resistant resin having translucency such as silicone resin is provided so as to cover the light emitting diode 17.

  On the back surface of the circuit board 16 in the LED mounting body 15, a power supply wiring board 25 that is electrically connected to the LED mounting body 15 and has wiring (not shown) on the front surface is provided. The power supply wiring board 25 is configured by forming a wiring on a metal plate made of copper or the like via an insulating layer made of a resin such as a resist. The power supply wiring board 25 supplies electricity to the light emitting diode 17. A power supply (not shown) is connected.

The light source device of this example includes a bottom plate 36 perpendicular to the longitudinal direction of the light guide 10 and a side plate 37 extending along the longitudinal direction of the light guide 10 continuously to the periphery of the bottom plate 36, for example, a metal such as aluminum urine. The support member 35 having an L-shaped cross section is formed, and the power supply wiring board 25 is disposed and fixed on the surface of the bottom plate 36 of the support member 35, while the side plate 37 of the support member 35 is attached to the base 30. It is fixed.
Further, a radiator 38 is provided on the back surface of the bottom plate 36 in the support member 35.

A metal light reflecting member 20 is provided between the light guide 10 and the power supply wiring board 25. Specifically, as shown in FIG. 2, the light reflecting member 20 has a tapered light reflecting surface 22 whose diameter increases from the proximal end located close to the power supply wiring board 25 toward the distal end. The outer peripheral contour formed on the peripheral surface and extending in the longitudinal direction of the light guide 10 was formed integrally with the rectangular cylindrical light reflecting surface forming portion 21 and the tip of the light reflecting surface forming portion 21 continuously. And a cylindrical light guide receiving part 23 extending in the longitudinal direction of the light guide 10, and one end of the light guide 10 is inserted into the light guide receiving part 23 and received, The light reflecting member 20 is disposed so that the light reflecting surface 22 surrounds the optical path between the LED mounting body 15 and the light guide body 10.
The light reflecting member 20 has a plurality of projecting leg portions 24 that protrude from the base end face of the light reflecting surface forming portion 21 toward the power supply wiring board 25 and come into contact with non-wiring regions on the surface of the power supply wiring board 25. They are formed apart from each other. In the illustrated example, a total of four projecting leg portions 24 are formed at the four corners of the base end surface of the light reflecting surface forming portion 21.
The light reflecting member 20 is fixed to the power supply wiring board 25 or the base 30 with, for example, screws.

The light reflecting member 20 is made of, for example, aluminum, and the light reflecting surface 22, that is, the inner peripheral surface of the light reflecting surface forming portion 21 is mirror-finished.
The protruding height of the protruding leg portion 24 is greater than the thickness of the circuit board 16 in the LED mounting body 15, whereby the base end face of the light reflecting surface forming portion 21 is separated from the surface of the circuit board 16 in the LED mounting body 15. It is in a separated state. Since the protruding height of the protruding leg 24 is larger than the thickness of the circuit board 16 in the LED mounting body 15, the light reflecting member 20 is aligned and the power supply wiring board 25 or the base when manufacturing the light source device. When fixing to 30, it is possible to prevent the base end surface of the light reflecting surface forming portion 21 from contacting the surface of the circuit board 16 in the LED mounting body 15 and damaging the wiring of the circuit board 16.
Specifically, the protruding height of the protruding leg 24 is preferably 0.8 to 1.1 mm.
Further, the separation distance between the plane level where the base end face of the light reflecting surface forming portion 21 in the light reflecting member 20 is located and the plane level where the surface of the circuit board 16 is located is 0.12 to 0.42 mm. Preferably there is.

  As an example of the dimensions of each member of the light source device, the light guide 10 has a total length of 340 mm, the maximum diameter is 6.0 mm, and the LED mounting body 15 has a circuit board 16 with a dimension of 3.0 mm × 3.0 mm × 0.68 mm, the diameter of the sealing body 18 is 4.8 mm, the light reflecting member 20 has a length of the light reflecting surface forming portion 21 of 2.2 mm, and an inner diameter of the base end of the light reflecting surface forming portion 21 is 5.2 mm. The inner diameter of the tip of the light reflecting surface forming part 21 is 3.2 mm, the outer circumference of the light reflecting surface forming part 21 is 10 mm × 10 mm, the length of the light guide receiving part 23 is 2.8 mm, and the light guide receiving part 23 has an inner diameter of 5.2 mm, each projecting leg 24 has a projecting height of 0.9 mm, each projecting leg 24 has a vertical and horizontal dimension of 1.5 mm × 1.5 mm, and a power supply wiring board 25 has a dimension of 13 mm. X30 mm x 1.0 mm.

  In the light source device described above, the light emitted from the light emitting diode 17 in the LED mounting body 15 is directly or light reflecting member via the sealing body 17 and the optical path between the LED mounting body 15 and the light guide body 10. The light is incident on the light guide 10 from one end surface 13 of the light guide 10 while being reflected by the light reflecting surface 22, and the incident light is reflected on the peripheral surface by the light guide 10. In addition to being guided in the longitudinal direction of the body 10, it is reflected toward the light exit surface 11 by the small prism group 12, and this reflected light is emitted from the light exit surface 11 of the light guide 10 and placed on, for example, a document table. The original surface of the original is irradiated. At this time, one end portion of the light guide 10 is heated by receiving light and heat from the LED mounting body 15.

  Thus, according to the light source device of the present invention, the light reflecting member 20 having the light reflecting surface forming portion 21 that surrounds the optical path between the LED mounting body 15 and the light guide 10 is made of a metal with high heat dissipation. Therefore, even when the amount of light incident on the one end surface 13 of the light guide 10 is increased, the one end of the light guide 10 is suppressed from being heated to a high temperature. It is possible to prevent thermal deformation from occurring at one end of the light guide 10. In addition, the light reflecting member 20 has a plurality of projecting leg portions 24 that protrude from the base end face of the light reflecting surface forming portion 21 toward the power supply wiring board 25 and come into contact with non-wiring regions on the surface of the power supply wiring board 25. As a result, the base end surface of the light reflecting surface forming portion 21 is separated from the surface of the power supply wiring board 25, so that the wiring between the wires formed on the surface of the power supply wiring board 25 via the light reflecting member 20. And a short circuit does not arise in the surface of the circuit board 16 in the LED mounting body 15. FIG.

FIG. 3 is an explanatory cross-sectional view showing the configuration of the main part of the light source device according to the second embodiment of the present invention. In this light source device, the surface of the power supply wiring board 25 and the base of the light reflecting surface forming portion 21 in the light reflecting member 20 are provided between the circuit board 16 in the LED mounting body 15 and the light reflecting surface forming portion 21 in the light reflecting member 20. The configuration is the same as that of the light source device according to the first embodiment, except that a light blocking body 40 that blocks light traveling toward the gap between the end surface and the end surface is provided.
The light shielding body 40 has a through-hole 41 having a diameter slightly smaller than the diameter of the sealing body 18 in the LED mounting body 15 and is formed of a plate-like body formed of a colored heat-resistant resin material having electrical insulation, The light reflecting surface forming portion 21 has a thickness smaller than the distance between the plane level where the base end face is located and the plane level where the surface of the circuit board 16 is located. By inserting the sealing body 18, the light shielding body 40 is arranged so that the inner peripheral surface of the through hole 41 surrounds the periphery of the sealing body 18.
As the heat resistant resin material constituting the light shielding body 40, polycarbonate, polyether ether ketone, or the like can be used.
Further, the color of the light shielding body 40 is not particularly limited as long as the light shielding property is exhibited.

  According to such a light source device, the same effect as that of the light source device according to the first embodiment can be obtained, and light from the LED mounting body 15 can be reflected by the light shielding member 20 on the light reflecting surface of the light reflecting member 20. It can be prevented from being emitted from the gap between the base end face of the forming portion 21 and the surface of the power supply wiring board 25, and thereby the base end face of the light reflecting surface forming portion 21 and the surface of the power supply wiring board 25 can be prevented. Generation of stray light due to light being emitted from the gap between them can be prevented.

FIG. 4 is an explanatory cross-sectional view showing the configuration of the main part of the light source device according to the third embodiment of the present invention. This light source device has a light reflecting surface 46 that surrounds the periphery of the sealing body 18 in the LED mounting body 15 between the circuit board 16 in the LED mounting body 15 and the light reflecting surface forming portion 21 in the light reflecting member 20. The configuration is the same as that of the light source device according to the first embodiment except that an insulating light reflecting member 45 made of an electrically insulating material is provided.
More specifically, the insulating light reflecting member 45 has a through hole 47 penetrating in the thickness direction, and is formed of a heat-resistant resin material colored in a color having a high visible light reflectance such as white. The light reflecting surface 46 is formed on the inner peripheral surface of the through hole 47. The light reflecting surface 46, which is the inner peripheral surface of the insulating light reflecting member 45, approaches the light reflecting surface forming portion 21 from the back surface close to the circuit board 16, as shown in FIG. It is formed in a tapered shape whose diameter is increased toward the surface where it is located.

  Here, in the cross section along the longitudinal direction of the light guide 10, the angle formed by the longitudinal direction of the light guide 10 and the light reflecting surface 22 of the light reflecting member 20 is the same as the longitudinal direction of the light guide 10 and the insulating light. It is preferably configured to be smaller than an angle formed by the light reflecting surface 46 of the reflecting member 45. According to such a configuration, a high light collecting function is obtained by the light reflecting surface 22 of the light reflecting member 20 and the light reflecting surface 46 of the insulating light reflecting member 45. Can be suitably performed, and thereby a higher light utilization rate can be obtained.

The insulating light reflecting member 45 has a thickness smaller than the distance between the plane level where the base end face of the light reflecting surface forming portion 21 of the light reflecting member 20 is located and the plane level where the surface of the circuit board 16 is located. And the opening diameter of the back surface of the insulating light reflecting member 45 is slightly smaller than the diameter of the sealing body 18 in the LED mounting body 15, and the surface is on the base end face of the light reflecting surface forming portion 21. They are in contact with each other and the back surface is separated from the surface of the circuit board 16 in the LED mounting body 15 via the gap S. According to such a configuration, since the insulating light reflecting member 45 does not come into contact with the surface of the circuit board 16 in the LED mounting body 15, the wiring of the circuit board 16 is damaged during the manufacture of the light source device. This can be prevented.
As the heat resistant resin material constituting the insulating light reflecting member 45, polycarbonate, polyether ether ketone, or the like can be used.

  According to such a light source device, the same effects as the light source devices according to the first and second embodiments can be obtained, and the surface of the power supply wiring board 25 and the light reflecting surface of the light reflecting member 20 can be obtained. Since the light which goes to the gap | interval between the base end surfaces of the formation part 21 is reflected by the insulating light reflection member 45 and enters into the one end surface 13 of the light guide 10, a high light utilization rate can be obtained.

The light source device of the present invention has been described with reference to three embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made.
For example, a plurality of LED mounting bodies 15 may be disposed on the power supply wiring board 25, and a plurality of light emitting diodes 17 may be disposed on the circuit board 16 in the LED mounting body 15. .
In each of the light source devices according to the first to third embodiments, the light reflecting surface 22 of the light reflecting member 20 is a cross section along the axial direction of the light reflecting surface forming portion 21. The line from the proximal end to the distal end of the light reflecting surface forming portion 21 is straight, but the line from the proximal end to the distal end of the light reflecting surface forming portion 21 is parabolic, that is, the light reflecting surface is parabolic. It may consist of a plane mirror.
Further, the projecting leg portion 24 is not limited to the one shown in FIG. 2 as long as the base end surface of the light reflecting surface forming portion 21 is arranged away from the surface of the power supply wiring board 25. For example, FIG. As shown in FIG. 3, the light reflecting surface forming part 21 may have a configuration having two protruding legs 24 formed along one side edge of the base end face and the other side edge opposite to the one side edge.
Further, in the light source device according to the third embodiment, the light reflecting surface 46 of the insulating light reflecting member 45 has a cross section perpendicular to the surface of the insulating light reflecting member 45 in the insulating light reflecting member 45. The line from the back surface to the front surface is straight, but the line from the back surface to the front surface of the insulating light reflecting member 45 is parabolic, that is, the light reflecting surface 46 is a parabolic mirror. Also good.

DESCRIPTION OF SYMBOLS 10 Light guide 11 Light emission surface 12 Micro prism group 13 One end surface 15 LED mounting body 16 Circuit board 17 Light emitting diode 18 Sealing body 20 Light reflection member 21 Light reflection surface formation part 22 Light reflection surface 23 Light guide body acceptance part 24 Projection leg 25 Power supply wiring board 30 Base 35 Support member 36 Bottom plate 37 Side plate 38 Radiator 40 Light shield 41 Through hole 45 Insulating light reflecting member 46 Light reflecting surface 47 Through hole 70 Light guide 71 Light emitting surface 72 Micro prism Group 75 One end face 80 Power supply wiring board 81 Diode element 82 Conductive adhesive 83 Wire wiring 85 Light emitting diode 86 Micro bump 87 Sealing body 90 Light reflecting member 91 Light reflecting surface S Gap

Claims (4)

A rod-shaped light guide,
An LED which is composed of a circuit board, a light emitting diode disposed on the surface of the circuit board, and a light-transmitting sealing body provided so as to cover the light emitting diode, and is disposed so as to face one end surface of the light guide body An implementation,
A power supply wiring board disposed on the back surface of the circuit board in this LED mounting body and electrically connected to the LED mounting body, and having wiring on the surface,
A cylindrical light reflecting surface forming portion having an inner peripheral surface formed with a light reflecting surface whose diameter increases toward the tip from the proximal end positioned close to the power supply wiring board , and the tip of the light reflecting surface forming portion. A cylindrical light guide receiving portion that extends continuously in the longitudinal direction of the light guide, and one end of the light guide is inserted into the light guide receiving portion, and the light reflecting surface Comprising a metal light reflecting member arranged so as to surround an optical path between the LED mounting body and the light guide body,
The light reflecting member has a plurality of projecting leg portions that project from the base end face of the light reflecting surface forming portion toward the power supply wiring board and come into contact with non-wiring regions on the surface of the power supply wiring board. A light source device, characterized in that a base end surface of a reflection surface forming portion is disposed so as to be separated from a surface of the circuit board.   2. The light source device according to claim 1, further comprising: a light shielding unit that shields light traveling toward a gap between a surface of the power supply wiring board and a base end surface of the light reflection surface forming unit.   Between the circuit board and the light reflecting surface forming portion, the surface surrounding the sealing body is located near the light reflecting surface forming portion from the back surface located close to the circuit substrate. The light source device according to claim 1, wherein an insulating light reflecting member made of an electrically insulating material having a light reflecting surface that expands in diameter as it goes is provided. The light source device according to any one of claims 1 to 3, wherein the power supply wiring board is formed by wiring on a metal plate via an insulating layer.

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