JP2006279781A - Illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator which uniformly and efficiently irradiates a rectangular illumination range with illuminating light. <P>SOLUTION: The illuminator includes: a columnar light transmission member 1 disposed approximately in parallel with a long side direction of a rectangular illumination range 200; a light source part 7 disposed near both ends of the columnar light transmission member 1; a band-like light scattering member 3 disposed in the long side direction in the outer periphery of the columnar light transmission member 1; and a reflection member 5 which is disposed at a side opposing the light scattering member 3 with respect to a central axis of the columnar light transmission member 1 and includes a reflection plane 5a comprised of a curved surface. In such a case, light from the light source part 7 is scattered and reflected on a light scattering plate 3, emitted from the columnar light transmission member 1, reflected on the reflection plane 5a of the reflection member 5 and converged within the rectangular illumination range 200. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device that illuminates a rectangular region used in an image input device or the like.

Conventionally, an illumination device that illuminates a rectangular region of an image input device such as a scanner has been proposed. In particular, using a cylindrical light guide member such as glass, the light source light is introduced from the end face of the light guide member, and the light source light is irregularly reflected by a scattering plate arranged along the axial direction on a part of the outer periphery of the light guide member. There has been proposed an illuminating device that illuminates a rectangular region by emitting light scattered and emitted from a light guide member from a strip-shaped gap of a cylindrical reflection member provided around the light guide member (for example, a patent) Reference 1).
Japanese Patent Laid-Open No. 9-9006

  However, in the disclosed example of Patent Document 1, the illumination light emitted from the strip-shaped gap of the cylindrical reflecting member is divergent light that spreads in the width direction of the gap as it is away from the gap, so that the illumination efficiency is reduced. There is a problem to say.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination device that irradiates illumination light uniformly and efficiently over a rectangular illumination range.

  In order to achieve the above object, the present invention provides a columnar light guide member disposed substantially parallel to the long side direction of the rectangular illumination range, a light source unit disposed near both ends of the columnar light guide member, A strip-shaped light diffusion member disposed along the long side direction on the outer periphery of the cylindrical light guide member, and a curved surface disposed on the side facing the light diffusion plate with respect to the central axis of the cylindrical light guide member The rectangular illumination by reflecting the light from the light source part by being scattered and reflected by the light diffusing plate, being emitted from the cylindrical light guide member, and reflected by the reflecting surface of the reflecting member. Provided is an illuminating device that is focused on a range.

  Moreover, in the illuminating device of this invention, it is preferable that the said rectangular illumination range is located in the surface substantially perpendicular | vertical to the straight line which connects the curvature center of the said reflective surface, and the center of the said cylindrical light guide member.

  Moreover, in the illuminating device of this invention, it is preferable that the said reflective surface consists of a combination of circular arc shape, elliptical shape, parabolic shape, or a plane mirror.

  Moreover, in the illuminating device of this invention, it is preferable that the curvature radius of the said reflective surface is 3 times or more of the radius of the said cylindrical light guide member.

  Moreover, in the illuminating device of this invention, it is preferable that the said cylindrical light guide member and the said rectangular illumination range are positioned optically substantially conjugate with respect to the said reflective surface.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which irradiates illumination light uniformly and efficiently to a rectangular illumination range can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall perspective view of a lighting device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along plane AA in FIG. FIG. 3 is a diagram for explaining a light guide state of a cylindrical light guide member used in the present embodiment.

  1 and 2, the illumination device 100 according to the present embodiment is provided on the outer peripheral side surface of a cylindrical light guide member 1 (hereinafter referred to as a light guide member) formed of glass or an optically transparent resin material. The light diffusing member 3 is disposed along the long axis direction of the light guide member 1 and the reflecting member 5 is disposed on the side facing the light diffusing member 3 with respect to the central axis O of the light guide member 1. ing.

  The light diffusing member 3 is formed by sticking an elongated belt-like light diffusing sheet on the side surface of the light guide member 1. The reflecting member 5 is composed of a reflecting surface 5a made of a curved surface having a radius of curvature R.

  In the vicinity of both ends 1 a and 1 b of the light guide member 1, substrates 9 and 9 on which a plurality of light sources 7 (for example, LEDs, hereinafter referred to as LEDs) are fixed are arranged. On the surface of the substrate 9 on the light guide member 1 side where the LED 7 is not fixed, a reflective surface that reflects the light of the LED 7 is formed.

  As shown in FIG. 3, light from a plurality of light sources 7 disposed in the vicinity of both ends 1 a and 1 b of the light guide member 1 enters the light guide member 1 from the end surfaces 1 a and 1 b of the light guide member 1. . The light incident on the light guide member 1 travels by being totally reflected by the inner surface of the light guide member 1, enters the light diffusion member 3, is scattered, and is emitted from the side surface of the light guide member 1. The scattered light is mainly emitted in a direction facing the light diffusion member 3 with respect to the central axis O of the light guide member 1.

  Of the light emitted from the LED 7 on one end face 1 a, the light that has not entered the light scattering member 3 travels through the light guide member 1, reaches the other end face 1 b, and is reflected by the reflecting surface of the substrate 9. Then, it enters the light guide member 1 again, is scattered by the light scattering member 3, and is emitted from the light guide member 1. In this way, the light from the LED 7 is scattered by the light scattering member 3 while reciprocating in the light guide member 1, and almost all is emitted from the light guide member 1.

  By covering the circumferential surface of the light guide member 1 widely with the light scattering member 3, the light emitted in the direction of the reflection member 5 can be increased, but on the other hand, total reflection in the light guide member 1 is prevented. The uniformity of the illumination light in the axial direction of the light guide member 1 is impaired. Accordingly, the region where the light scattering member 3 covers the circumferential surface of the light guide member 1 is determined from the balance between the uniformity of the illumination light in the axial direction and the illumination efficiency. It is desirable to configure so as to cover half or less of the circumferential surface.

  The light emitted from the light guide member 1 enters the reflection surface 5a of the reflection member 5 and is reflected, and is collected on the rectangular illumination region 200 by the reflection surface 5a. At this time, since the light guide member 1 and the rectangular illumination region 200 are disposed in a substantially conjugate positional relationship, the light emitted from the light guide member 1 can efficiently illuminate the rectangular illumination region 200.

  The rectangular illumination area 200 is disposed in a plane X that is substantially perpendicular to a straight line OP that connects the center O of the light guide member 1 and the center of curvature P of the reflecting surface of the reflecting member 5. Further, the radius of curvature R of the reflecting member 5 is three times or more the radius r of the light guide member 1. For example, when r = 5 mm, R = 41 mm (about 8 times), R = 25 mm (about 5 times), R = 18 mm (about 3.6 times), etc. were used.

  By setting the radius of curvature R of the reflecting surface 5a of the reflecting member 5 to be three times or more the radius r of the light guide member 1, a certain amount of space between the light guide member 1 and the reflecting member 5 can be secured. Uniformity can be ensured, and more light emitted from the light guide member 1 can be reflected, so that the illumination light rate can be improved. If it is less than three times, it is possible to reduce the size of the illumination device 100, but the distance between the light guide member 1 and the reflection member 5 becomes too narrow, and it becomes difficult to ensure the uniformity of the illumination light. It becomes difficult to improve efficiency.

  Thus, the illuminating device 100 which concerns on this embodiment is comprised.

FIG. 4 is a diagram illustrating an example of the illuminance distribution of the lighting apparatus according to the present embodiment. The horizontal axis represents the distance (unit: mm) in the major axis or minor axis direction with the center position in the major axis direction of the rectangular illumination area 200 as the origin. The vertical axis represents the illumination intensity (unit: W / mm ² ). The broken line indicates the distribution in the long axis direction, and the solid line indicates the distribution in the short axis direction. As compared with the conventional method using the same light source 7 and the same light guide member 1, it was confirmed that the illumination intensity is strong and the fluctuation range is small in both the long axis direction and the short axis direction.

  As described above, according to the present invention, the light that is incident on the light guide member 1 from the light source 7, is scattered by the light scattering member 3, and is emitted from the light guide member 1 is efficiently collected by the reflection member 5. The rectangular illumination area 200 provided at a position substantially conjugate with 1 can be illuminated uniformly and brightly.

  In addition, it is also possible to arrange | position RGB LED other than white LED, and to irradiate color illumination light to LED7 of a light source. Moreover, the reflective surface 5a of the reflective member 5 may be configured by an elliptical shape, a parabolic shape, or a curved surface obtained by combining a plurality of planes, in addition to the circular arc shape.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

It is a whole perspective view of the illuminating device which concerns on embodiment of this invention. It is sectional drawing along the AA surface of FIG. The figure explaining the light guide state of the cylindrical light guide member used by this Embodiment. It is a figure which shows an example of the illumination intensity distribution of the illuminating device which concerns on this Embodiment.

Explanation of symbols

1 Cylindrical light guide member (light guide member)
3 Light diffusing member 5 Reflecting member 7 Light source (LED)
9 Substrate 100 Lighting device 200 Rectangular illumination area

Claims (5)

A cylindrical light guide member disposed substantially parallel to the long side direction of the rectangular illumination range;
A light source unit disposed in the vicinity of both ends of the cylindrical light guide member;
A strip-shaped light diffusing member disposed along the long side direction on the outer periphery of the cylindrical light guide member;
A reflective member having a reflective surface disposed on the side facing the light diffusion plate with respect to the central axis of the cylindrical light guide member,
Illumination characterized in that light from the light source unit is scattered and reflected by the light diffusing plate, emitted from the cylindrical light guide member, reflected by the reflecting surface of the reflecting member, and collected in the rectangular illumination range. apparatus.   The illumination device according to claim 1, wherein the rectangular illumination range is positioned in a plane substantially perpendicular to a straight line connecting the center of curvature of the reflecting surface and the center of the cylindrical light guide member.   The lighting device according to claim 1, wherein the reflection surface is formed of an arc shape, an ellipse shape, a parabolic shape, or a combination of flat mirrors.   4. The lighting device according to claim 1, wherein a radius of curvature of the reflecting surface is three times or more of a radius of the cylindrical light guide member.   5. The illumination device according to claim 1, wherein the cylindrical light guide member and the rectangular illumination range are positioned optically conjugate with respect to the reflective surface. 6.

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