JP2009181742A - Linear lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear illumination device capable of forming linear illumination light of uniform illuminance in a simple design. <P>SOLUTION: By dividing a light guide part 20 guiding light from a light source 11 to a converging lens 25 with a plurality of light guide cells 21 linearly and continuously arranged along the light source 11, light emitted from each part of the light source 11 is to contribute in limited way as illumination light for each specific area regulated by each light guide cell 21. At that time, side walls 23 of each light guide cell 21 are structured of reflecting faces expanded toward a converging lens 25 side from a light-emitting part 12 side, and incident light from the light-emitting part 12 is made reflected at the side walls 23 and guided toward a converging lens 25 side, thereby, the light incident into the converging lens 25 from each light guide cell 21 is uniformalized and made closer to parallel light. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear illumination device that condenses illumination light linearly in a continuous linear narrow range.

  In a copying machine, a facsimile machine, and the like, a linear illumination device that forms an elongated linear illumination light is used as illumination light for image reading. In general, a cylindrical lens (condenser lens) is used in this linear illumination device for forming a linear beam at a focal point by changing incident light only in one axial direction.

In this type of illumination device, a light guide is connected to the incident side of the cylindrical lens in order to obtain a linear illumination light with uniform illuminance by smoothing the amount of light incident on each part of the cylindrical lens from the light source. It is common. As an illuminating device including such a light guide unit, for example, in Patent Document 1, light sources made of LED chips or the like are attached to both end faces in the longitudinal direction of a light guide unit formed continuously with a condenser lens unit. At the same time, a technique is disclosed in which a diffuse reflection part that faces the cylindrical lens is provided with a light guide part interposed therebetween.
JP 2000-21221 A

  However, in the technique disclosed in Patent Document 1 described above, in order to smooth the amount of light incident on the cylindrical lens, a complicated design such as changing the area of the diffuse reflection portion according to the relative distance to the light source is used. Need. That is, in the above-described technique, the light diffused from the diffuse reflection part located in each part of the light guide part affects each other. For example, the diffuse reflection parts are simply arranged uniformly along the longitudinal direction of the light guide part. With such a configuration, the amount of light incident on the cylindrical lens cannot be made uniform, and there is a possibility that the illuminance distribution of the linear illumination light may be uneven due to the concentration of diffused light at the center.

  An object of this invention is to provide the linear illuminating device which can form the linear illumination light of uniform illumination intensity by simple design.

  The present invention provides a light source in which light emitting units are arranged in a straight line, a light guide unit arranged in a straight line facing the light source, and light guided from the light source through the light guide unit in a straight line. A condensing lens that condenses the light guide, and the light guide unit is configured by a plurality of light guide cells arranged linearly along the light source, and the peripheral surface of each light guide cell is It is characterized by comprising a reflecting surface that expands from the light emitting part side to the condenser lens side.

  According to the linear illumination device of the present invention, it is possible to form linear illumination light with uniform illuminance by a simple design.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is an exploded perspective view showing a part of the lighting device in a cutaway state, FIG. 2 is a perspective view showing a part of the lighting device in a cutaway state, and FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is a sectional view taken along the line V-V in FIG. 3, and FIG. FIG. 7B is an explanatory diagram showing the behavior of the illumination device along the longitudinal direction of the illumination device. FIG. 7B is an explanatory diagram showing the behavior of the illumination light along the short direction of the illumination device. FIG. It is.

  The illuminating device 1 of this embodiment shown in FIGS. 1 and 2 is, for example, for forming linear illuminating light for a copying machine. For example, the illuminating device 1 has light emitting portions arranged linearly. A light source unit 2 and an optical member 3 for dimming light from the light source unit 2 into a linear light beam.

  The light source unit 2 includes, for example, a glass substrate 10 having a substantially rectangular shape in plan view, and a light source 11 made of electroluminescence (EL) is disposed on the glass substrate 10.

  Specifically, the light source 11 according to the present embodiment is configured by arranging a plurality of (for example, four) light emitting units 12 made of EL in a straight line. A plurality of (for example, four) positive electrodes 15 and a single negative electrode 16 are disposed on the back surface of the substrate 10 (see FIG. 3).

  Each positive electrode 15 is composed of, for example, a strip-shaped transparent conductive film made of ITO or the like, and these are arranged in parallel at predetermined equal intervals so as to extend along the short direction of the glass substrate 10, respectively. ing.

  On the other hand, for example, the negative electrode 16 is formed by continuously forming strip-shaped first and second conductive portions 16a and 16b made of a metal conductive film having high reflectivity such as aluminum in an L shape. The first conductive portion 16 a constituting the negative electrode 16 is arranged in parallel with the positive electrode 15 so as to extend along the short direction of the glass substrate 10. On the other hand, the second conductive portion 16 b extends along the longitudinal direction of the glass substrate 10 and is superimposed on the upper layer of one end portion of each positive electrode 15.

  A hole transport layer, a light emitting layer, and an electron transport layer (all not shown) are interposed in the overlapping region of each positive electrode 15 and the negative electrode 16, and between the positive electrode 15 and the negative electrode 16. When a voltage is applied to the light emitting layer, the light emitting layer emits light by combining the holes that have passed through the hole transporting layer and the electrons that have passed through the electron transporting layer. The light emitted from the light emitting layer is reflected by the negative electrode 16 and transmitted through the positive electrode 15 and the glass substrate 10 or directly transmitted through the positive electrode 15 and the glass substrate 10 to be emitted. . Thereby, the area | region where the positive electrode 15 and the negative electrode 16 overlapped functions as the light emission part 12 which light-emits planarly by making the surface side of the glass substrate 10 into a light emission surface.

  The optical member 3 includes a light guide unit 20 disposed to face the light source 11 and a condensing lens 25 that condenses light guided from the light source 11 via the light guide unit 20 in a linear shape.

  The light guide unit 20 is composed of a plurality of light guide cells 21 arranged linearly along the light source 11. In the present embodiment, each light guide cell 21 has an incident surface 22 in contact with the glass substrate 10 corresponding to the light emitting unit 12 on the base end side, and four side walls 23 continuous to the incident surface 22 are light emitting units. It is inclined to expand from the 12 side to the condensing lens 25 side. Thereby, each light guide cell 21 is constituted by a prism-shaped member having a substantially inverted pyramid shape whose front ends are connected to each other, and guides incident light from the incident surface 22 to the condenser lens 25 while internally reflecting (FIG. 6).

  At that time, by setting the inclination angle θ (see FIGS. 4 and 5) of the side wall 23 to an appropriate value, the light guide cell 21 adjusts the light emitted from the light emitting unit 12 to be close to parallel light by reflection. However, the light is guided to the condenser lens 25. In the present embodiment, the inclination angle θ of each side wall 23 is set within a range of 18 ° to 20 °, for example.

  A condensing lens 25 is connected to the tip of the light guide 20 in which the light guide cells 21 are continuously arranged. In the present embodiment, the condensing lens 25 is configured by a cylindrical lens that condenses incident light from each light guide cell 21 by changing only the short direction of the optical member 3 (see FIG. 6). Here, the condensing lens 25 can be configured as a member separate from the light guide unit 20, but in the present embodiment, it is guided by a light-transmitting resin material for the purpose of simplifying the structure. It is integrally formed with the optical part 20.

  For example, as shown in FIG. 2, the optical member 3 configured in this manner has the light source unit 2 in which the incident surface 22 of each light guide cell 21 is bonded to the glass substrate 10 via a transparent adhesive or the like. Fixed. In this case, the refractive index of the transparent adhesive is close to the refractive index of the glass substrate 10 or the optical member 3 in order to prevent the light from the light emitting unit 12 from being totally reflected by the incident surface of each light guide cell 21. desirable. In order to prevent unnecessary light leakage, the optical member 3 is held in a state in which the periphery of the light guide 20 is surrounded by the frame body 27.

  According to such an embodiment, the light guide 20 that guides the light from the light source 11 to the condenser lens 25 is divided and configured by the plurality of light guide cells 21 that are linearly provided along the light source 11. Thus, the light emitted from each part on the light source 11 can be limitedly contributed as illumination light for each specific region defined by each light guide cell 21. Therefore, the illuminance of the linear illumination light can be homogenized over the entire light without performing complicated design or the like. In this case, in particular, the side wall 23 (circumferential surface) of each light guide cell 21 is configured by a reflection surface that expands from the light emitting unit 12 side to the condenser lens 25 side, and incident light from the light emitting unit 12 is transmitted by the side wall 23. By guiding to the condensing lens 25 side while reflecting, the light incident on the condensing lens 25 from each light guide cell 21 can be homogenized and can be brought close to parallel light. Thereby, the illuminance of the illumination light condensed linearly by the condenser lens 25 can be made more uniform, and the light condensing degree can be improved. In addition, when the side wall 23 of the light guide cell 21 is inclined, a part of the light can be leaked to the adjacent light guide cell 21 side, and the light guide unit 20 is divided by the plurality of light guide cells 21. Moreover, it can suppress exactly that a dark part is formed in the illumination light between the light guide cells 21. Accordingly, in the linear illumination device 1 of the present embodiment, for example, as shown in FIG. 7, linear illumination light without uneven illuminance can be obtained.

  In this case, the light supplied from the light source 11 can be used efficiently as illumination light by disposing the light emitting unit 12 intermittently corresponding to the incident surface 22 of each light guide cell 21.

  Further, by using an EL or the like that emits surface light as each light emitting unit 12, light incident on the condenser lens 25 from each light guide cell 21 can be easily homogenized.

  By the way, the light source unit 2 used in the linear illumination device 1 of the present invention is not limited to a light emitting unit that is arranged in a straight line, such as an EL, for example. A plurality of light emitting elements that emit light in the form of dots, such as diodes (LEDs), may be arranged in a straight line. In this case, for example, as shown in FIG. 8, the light source unit 2 employs a circuit board 30 such as a printed wiring board instead of the glass substrate, and includes a dotted light emitting portion 31 a on the circuit board 31. The main part is configured by mounting a plurality of LEDs 31 linearly. At that time, it is possible to arrange a single LED 31 corresponding to each light guide cell 21 on the circuit board 31. For example, as shown in FIG. A plurality of (for example, two) LEDs 31 may be arranged corresponding to each other.

  Here, although it is generally difficult to obtain linear illumination light with a short irradiation distance using a point light source, in such a case as well, incident light from each point light emitting unit 31a is used. With the above-described configuration in which the light is guided to the condensing lens 25 while being totally reflected in the light guide cell 21, and is condensed only in the short direction in the condensing lens 25, for example, as shown in FIG. As a result, it is possible to obtain linear illumination light that is sufficiently free of illuminance unevenness in a practical range.

  In the above-described embodiment, an example in which a plurality of light emitting units 12 are intermittently arranged in a straight line to configure a light source has been described. However, the present invention is not limited to this example. Of course, the light source may be constituted by a series of (single) elongate light emitting portions with respect to the light cell.

Exploded perspective view showing a part of the lighting device broken away The perspective view which fractures | ruptures and shows a part of illuminating device A plan view of the lighting device viewed from the bottom side Cross-sectional view of essential parts along line IV-IV in FIG. FIG. 3 is a cross-sectional view of an essential part taken along line VV in FIG. (A) is explanatory drawing which shows the behavior of illumination light along the longitudinal direction of an illuminating device, (b) is explanatory drawing which shows the behavior of illumination light along the transversal direction of an illuminating device. Chart showing illuminance distribution characteristics by lighting device (A) is explanatory drawing which shows the behavior of illumination light along the longitudinal direction of an illuminating device, (b) is explanatory drawing which shows the behavior of illumination light along the transversal direction of an illuminating device. Chart showing illuminance distribution characteristics by lighting device

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Linear illuminating device, 2 ... Light source unit, 3 ... Optical member, 10 ... Glass substrate, 11 ... Light source, 12 ... Light emission part, 15 ... Positive electrode, 16 ... Negative electrode, 16a ... 1st electroconductive part, 16b ... 2nd conductive part, 20 ... Light guide part, 21 ... Light guide cell, 22 ... Incident surface, 23 ... Side wall (circumferential surface), 25 ... Condensing lens, 27 ... Frame

Claims (4)

A light source in which light emitting parts are arranged in a straight line;
A light guide portion arranged linearly facing the light source;
A condensing lens that linearly condenses the light guided from the light source via the light guide,
The light guide unit is composed of a plurality of light guide cells arranged linearly along the light source,
The linear illumination device characterized in that the peripheral surface of each light guide cell is configured by a reflective surface that expands from the light emitting unit side to the condenser lens side.   The linear illumination device according to claim 1, wherein the light guide unit is formed integrally with the condenser lens.   3. The linear illumination according to claim 1, wherein the light source includes a plurality of light emitting units intermittently arranged linearly in each region corresponding to an incident surface of the light guide cell. apparatus.   The linear illumination device according to claim 3, wherein each of the light emitting units emits light in a planar shape or a dot shape.

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