JP2009259545A - Linear light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new light-emitting device small in size and light in weight to have a simple structure that is capable of uniformly emitting a sufficient quantity of light along the longitudinal direction. <P>SOLUTION: The light-emitting device 10 linearly emitting light includes an elongated case 2 having an opening 1 almost linearly extending in the longitudinal direction, and a plurality of LED light sources 4 arranged longitudinally at given intervals in the case 2. The case 2 has a diffusion reflection surface 5 inside the case 2. The LED light sources 4 are positioned inside the case 2 in the light-emitting device 10 so that light from the light sources 4 is emitted onto the diffusion reflection surface 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a linear light-emitting device using an LED as a light source, and an optical reading device including the linear light-emitting device.

  An example of a contact type image pickup apparatus 50 such as a conventional copying machine or facsimile is shown in FIG. In general, this type of contact-type imaging device includes a housing 59, a light source 54, a translucent plate 56, a lens 57, and a CCD element 58. The basic operating principle is that a document to be read is placed on a translucent plate 56, light is emitted toward the target to be read, and the light reflected from the document is imaged on a CCD 58 through a lens 57, thereby the document. Is read. Patent Document 1 discloses a fluorescent lamp 54 of an outer electrode type as a light source, an aperture section 51 provided, and this as an optical projection section.

  On the other hand, with the recent increase in brightness and efficiency of LEDs, there is a movement to utilize LEDs as a light source for optical readers such as scanners, taking advantage of the characteristics of LEDs with low power consumption and long life. .

  As one of such examples, as shown in FIG. 9, there is a linear light emitting device in which an LED array 64 in which a large number of LEDs are arranged at equal intervals is mounted on a long substrate 63. The light emission to the document surface was not sufficiently uniform, and there was still a problem as a light source for reading. By increasing the distance between the LED light source 64 and the original reading surface or decreasing the distance between the LEDs 64, the light emission can be made uniform to some extent, but there are problems such as an increase in the size and cost of the apparatus.

Further, Patent Document 2 discloses a method in which an optical film having a predetermined transmittance distribution is provided between an LED light source and a light-transmitting plate so as to reduce the size of the device and secure a sufficient amount of light. However, since the arrangement of the LEDs is inevitably determined according to the transmittance pattern of the optical film, there is no degree of freedom in design and efficiency is also reduced. Another method is to provide an LED element at the end of the light emitting device to obtain linear light emission from the end through the light guide. However, this type of light emitting device does not have sufficient light quantity, There are many problems in practical use, such as taking time to read.
JP 2002-190919 A Japanese Patent Laid-Open No. 10-23208

  Accordingly, an object of the present invention is to provide a compact and lightweight linear light-emitting device having a simple structure in view of various problems of the prior art, and to uniformly emit a sufficient amount of light along the longitudinal direction. The object is to provide a new light-emitting device that enables this.

  The present invention includes a long casing having an opening that extends substantially linearly in the longitudinal direction, and a plurality of LED light sources disposed inside the casing at predetermined intervals in the longitudinal direction. The light-emitting device that emits light in a linear shape, wherein the casing has a diffuse reflection surface therein, and the plurality of LED light sources irradiate the emitted light toward the diffuse reflection surface. It is positioned inside the housing as described above.

  According to the linear light-emitting device of the present invention, the light emitted from each LED light source is diffused and reflected at least once by the diffuse reflection surface provided inside the housing, despite the simple configuration. Since the body is irradiated, uniform light emission with no unevenness can be obtained.

Embodiments of the present invention will be described below with reference to the drawings attached to this specification.
A light-emitting device 10 according to an embodiment of the present invention shown in FIG. 1 includes a housing 2 having an opening 1 in the longitudinal direction, and a plurality of LEDs 4 arranged on an LED substrate 3 provided inside the housing 2. Consists of As is clear from the side sectional view of the light emitting device 10 of this embodiment shown in FIG. 2, the diffuse reflection surface 5 is formed inside the housing 2, and primary reflection of light emitted from the LED 4 is performed. Positioned relative to the LED to occur at the diffuse reflecting surface 5.
In the present specification, the term “inside” of the casing does not necessarily refer to the inner wall surface of the material body constituting the casing, but refers to the inner surface exposed to the space in the casing. Shall. That is, in the case where the reflective material layer is integrally formed on the inner wall of the housing, the reflective material layer formed on the inner wall becomes the “inside” housing.

  The housing 2 can be manufactured using a resin or a metal material by a known method such as extrusion. As an example, the housing 2 can be formed using white or milky white PC (polycarbonate) resin or ABS resin. In this case, the diffuse reflection surface 5 inside the housing 2 may be the inner wall surface of the resin material constituting the housing 2. Further, when the housing 2 is produced by molding a metal, the diffuse reflection surface 5 may be formed by subjecting the inner wall surface of the housing 2 to a surface treatment such as alumite. As another form, the diffuse reflection surface 5 may be configured as a white reflection surface formed by pasting white PET or the like on the inner wall of the housing 2, or a combination of a specular reflection surface and a white reflection surface is used. May be.

  The LEDs 4 are preferably arranged on the LED substrate 3 at substantially equal intervals, but are not necessarily arranged at equal intervals. The shape of the housing 2 or the diffuse reflection surface 5 as described below, and the LED 4 The interval between the LEDs can be appropriately determined by experiments or simulations performed under various conditions such as the arrangement position.

  The LED substrate 3 and the LED 4 can be attached to the housing 2 using various known means such as double-sided tape and adhesive, and a resin support (not shown) is attached to the substrate 3 and the housing 2. A method of fixing the substrate 3 and the LED 4 by using a claw for mounting (not shown) at a predetermined location of the housing 2 and using it to fix the substrate 3 can be adopted. .

  The LED 4 is positioned so that the central axis of the emitted light faces the diffuse reflection surface 5. That is, in the light emitting device 10 of the present invention, substantially all of the light emitted from the LED 4 strikes the diffuse reflection surface 5 at least once and is diffusely reflected, and then emitted through the opening 1. As a result of this diffuse reflection, the light emitted from each LED 4 is scattered and mixed with the light emitted from the other LEDs 4, thereby obtaining a uniform amount of light over the entire length of the opening 1 that is the light exit surface.

  The light emitting device 10 of the present invention can be used as a light source of an optical reading device such as a CIS (Contact Image Sensor) module. For example, linear light emitted from the light emitting device 10 is irradiated onto a reading target such as a document on which characters and images are written, and the reflected light is again taken into the sensor to obtain image information and the like. Although not shown, a publicly known device can be used as the other means constituting the reading device such as a lens and a CCD for collecting reflected light from the reading object.

An example of another embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a side cross-sectional view of the light-emitting device 12 according to one embodiment of the present invention. The light emitting device 12 is composed of the same components as the light emitting device 10 described above, but the cross section of the bottom of the housing 2 and the diffuse reflection surface 5 is formed into a substantially V shape.

  FIG. 4 is a side cross-sectional view of the light-emitting device 14 according to one embodiment of the present invention. In this embodiment, the LED array is configured by using side-emitting LEDs 4. FIG. 5 is a conceptual diagram showing the optical path of the emitted light from the side-emitting LED 4 with arrows. As shown in the drawing, the light emitted from the side surface of the LED 4 is reflected twice by the diffuse reflection surface 5 and then emitted through the opening 1. This embodiment employing the side-emitting LED 4 is advantageous in that the wiring of the LED 4 and the installation of the substrate 3 are easy, and the wall surface for mounting the LED 4 can be substituted by the side of the housing, so that the apparatus can be downsized. There is.

  FIG. 6 is a side sectional view of a light emitting device 16 according to another embodiment of the present invention. The casing 2 'and the diffuse reflection surface 5 of this embodiment are obtained by bending a metal long piece with a diffuse reflection material applied or pasted into a substantially V-shaped cross section. A side-emitting LED 4 is attached to the side surface of the housing 2 '. The basic operation principle is the same as that of the light emitting device 14 of the form shown in FIG.

  FIG. 7 is a perspective view illustrating a configuration example of an optical reading device 18 that uses the light emitting device 16 of the form shown in FIG. 6 as a light source. A pair of light emitting devices 16 are installed so that the light emitting surface (opening 1) is oriented to the reading surface, and sealed with a translucent plate 6 to be configured in the casing 9. The light emitted from the light emitting device 16 passes through the translucent plate 6 and is irradiated to a reading target (not shown), and the reflected light is condensed by the lens array 7 and read by the CCD array 8. As the lens array 7 and the CCD array 8, known ones can be used.

  Although several examples have been described as embodiments of the present invention with reference to the drawings, the shape of the housing 2 and the diffuse reflection surface 5, the arrangement of the LEDs 4, and the like are used for the light emitting device, for example, an optical reader. It can be appropriately determined according to requirements such as the shape and dimensions of the mounting portion. Also, a structure in which a predetermined pattern is provided on the surface of the diffuse reflection surface 5 to increase the scattering effect can be employed as appropriate.

1 is a perspective view illustrating a light-emitting device according to one embodiment of the present invention. FIG. 2 is a side sectional view of the light emitting device of FIG. 1. FIG. 10 is a side cross-sectional view of a light-emitting device of one embodiment of the present invention. FIG. 10 is a side cross-sectional view of a light-emitting device of one embodiment of the present invention. FIG. 5 is a conceptual diagram illustrating an optical path of outgoing light of the light emitting device of FIG. 4. FIG. 10 is a side cross-sectional view of a light-emitting device of one embodiment of the present invention. The perspective view of the optical reader provided with the light-emitting device of this invention. The perspective view which shows the conventional close_contact | adherence imaging device. The figure which shows the LED array light source for contact | adherence imaging devices.

Explanation of symbols

1 Opening 2 Housing 3 LED Board 4 LED
5 diffuse reflection surface 6 translucent plate 7 lens array 8 CCD array 9 casing 10 light emitting device 12 light emitting device 14 light emitting device 16 light emitting device

Claims (7)

A long casing having an opening extending substantially linearly in the longitudinal direction;
A plurality of LED light sources disposed inside the housing at predetermined intervals in the longitudinal direction;
A light emitting device that emits light in a linear form,
The housing has a diffuse reflection surface inside thereof,
The light emitting device according to claim 1, wherein the plurality of LED light sources are positioned inside the housing such that the emitted light is irradiated toward the diffuse reflection surface.   The light emitting device according to claim 1, wherein the LED light source is positioned so that an optical axis center of each LED light source is directed toward the diffuse reflection surface.   The light-emitting device according to claim 1, wherein each LED light source is a side-emitting LED. The light-emitting device according to claim 1, wherein the diffuse reflection surface is a white scattering surface.
Lighting device.   The light emitting device according to any one of claims 1 to 4, wherein the housing is made of metal and a white resin bonded together, and the inside of the housing is a white scattering surface.   The light emitting device according to claim 1, wherein an inner surface of the housing acts as a diffuse reflection surface.   The light-emitting device according to claim 1, wherein the light-emitting device is used as a light source of a CIS module.

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