JP2011014301A - Linear lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear lighting device capable of forming a linear light of high illuminance free from non-uniform brightness, using efficiently a light emitted from a light source.SOLUTION: A light emitting part 12 of the light source 11 is formed into a band shape extended linearly. An optical member 3 for converting the emitted light from the light emitting part 12 into the linear light is constituted to include a light guide part 20 with an incident face 21 extended oppositely to the light emitting part 12, a cylindrical lens part 22 formed integrally with the light guide part 20 in an opposite side of the incident face 21, and a reflecting optical part 23 formed integrally in short-directional both sides of the light guide part 20. A reflecting face 32 extended adjacently to a side face 24 is formed further in an outgoing side of the reflecting optical part 23, by a frame 4 surrounding the optical member 3. Thus, the linear light of high illuminance free from non-uniform brightness is formed, using efficiently the light emitted from the light source 11.

Description

  The present invention relates to a linear illumination device that collects illumination light in a continuous linear 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 this linear illumination device, a cylindrical lens is generally used as a condensing lens for forming a linear beam by changing only one axial direction with respect to the incident side.

  As such a linear illumination device, for example, in Patent Document 1, a rectangular parallelepiped light guide unit is integrally provided on the incident side of the cylindrical lens unit, and LED chips or the like are provided at both ends in the longitudinal direction of the light guide unit. A technique is disclosed in which a light source composed of the above is attached and a diffuse reflection part for diffusing and reflecting light incident on the light guide part from the light source is provided on the surface on the light guide part facing the cylindrical lens part.

JP 2000-21221 A

  By the way, when the linear illumination light is formed by arranging the LED chip or the like at the end portion in the longitudinal direction of the light guide as in the technique disclosed in the above-mentioned Patent Document 1, the linear illumination light with high illuminance is formed. There is a limit to forming the film over a wide range.

  Therefore, a surface on the light guide portion extending on the opposite side of the cylindrical lens portion (that is, a surface on the light guide portion located immediately below the cylindrical lens portion) is set as an incident surface, and an LED is formed along the incident surface. It is conceivable to arrange them in a straight line.

  However, when an LED that is a point light source is arranged directly below the cylindrical lens portion, luminance unevenness easily occurs in the illumination light. In general, since light emitted from a light emitting unit such as an LED is emitted in a wide range, it is difficult to condense all the light into a linear shape by the cylindrical lens unit, which may reduce the light use efficiency. There is.

  On the other hand, instead of a point light source such as an LED, it may be possible to improve luminance unevenness of illumination light by continuously arranging a surface light source such as organic electroluminescence (organic EL) along the incident surface. .

  However, when a surface light source such as an organic EL is employed instead of a point light source such as an LED, more light is diffused out of the optical path of the cylindrical lens portion, so that the reduction in light use efficiency becomes more noticeable. .

  An object of this invention is to provide the linear illuminating device which can form the linear light of high illuminance without the brightness nonuniformity using the light radiated | emitted from a light source efficiently.

  The present invention is integrally formed in the light guide unit, the surface light source in which the light emitting unit is formed in a strip shape, the light guide unit in which the incident surface extends opposite to the light emitting unit, and the opposite side of the incident surface, A cylindrical lens unit that condenses light incident on the light guide unit into a linear shape by refraction, and a cylindrical lens unit that is integrally formed on both sides of the light guide unit in the short-side direction and that is incident on the light guide unit. A reflection optical unit that totally reflects light emitted outside the optical path to the lens unit on the side surface and emits the light toward the focal point of the cylindrical lens unit, and a reflection surface that extends continuously to the side surface. And a reflecting member formed on the light exit side.

  According to the linear illumination device of the present invention, it is possible to form linear light with high illuminance without uneven brightness by efficiently using light emitted from a light source.

1 is an exploded perspective view showing a schematic configuration of a linear illumination device according to a first embodiment of the present invention. Same as above, top view of organic EL from bottom side Same as above, main part sectional view along the short direction of the linear illumination device As above, an explanatory diagram showing the behavior of the illumination light along the short direction of the linear illumination device As above, an explanatory diagram showing the illuminance distribution of illumination light along the short direction of the linear illumination device The principal part sectional view which concerns on the 2nd Embodiment of this invention, and follows the transversal direction of a linear illuminating device. As above, an explanatory diagram showing the behavior of the illumination light along the short direction of the linear illumination device As above, an explanatory diagram showing the illuminance distribution of illumination light along the short direction of the linear illumination device Same as above, main part sectional view showing a modification of the linear illumination device along the short direction Same as above, main part sectional view showing a modification of the linear illumination device along the short direction Same as above, main part sectional view showing a modification of the linear illumination device along the short direction

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
A linear illumination device 1 shown in FIG. 1 is, for example, for forming linear illumination light for a copying machine. For example, the linear illumination device 1 has a light emitting portion formed in a linear strip shape. The light source unit 2 includes an optical member 3 that converts light from the light source unit 2 into a linear light beam, and a frame 4 that houses the optical member 3 on the light source unit 2. For example, when the linear illumination device 1 is used as an illumination device for image reading of a copying machine, the linear illumination device 1 is applied to an irradiation target 100 such as a paper as shown in FIG. They are arranged opposite each other with a predetermined irradiation distance D (D = about several mm) apart. This irradiation distance is set to, for example, about D = 4 mm, although it depends on the specifications of the copying machine to be applied.

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

  Specifically, the light source 11 of the present embodiment includes a light emitting unit 12 interposed between a positive electrode 15 and a negative electrode 16 stacked on the back side of the glass substrate 10 to form a main part. (See FIGS. 1 and 2).

  The positive electrode 15 is composed of, for example, a strip-shaped transparent electrode film made of ITO or the like, and is arranged linearly so as to extend along the longitudinal direction of the glass substrate 10. Further, in the middle of the positive electrode 15, a terminal portion 15 a extending to one side in the short direction of the glass substrate 10 is integrally formed.

  On the other hand, the negative electrode 16 is composed of a strip-shaped electrode film made of a metal conductive film having high reflectivity such as aluminum, and is a straight line extending along the longitudinal direction of the glass substrate 10 on the upper layer of the positive electrode 15. Arranged in a shape. Further, terminal portions 16 a extending to one side in the short direction of the glass substrate 10 are integrally formed at both ends of the negative electrode 16, and these terminal portions 16 a are predetermined with respect to the terminal portion 15 a of the positive electrode 15. Spaced apart.

  Further, the light emitting portion 12 interposed in the overlapping region of the positive electrode 15 and the negative electrode 16 has a multilayer structure including a hole transport layer, a light emitting layer, an electron transport layer, and the like (all not shown). When a voltage is applied between the positive electrode 15 and the negative electrode 16, light is emitted by combining holes that have passed through the hole transport layer and electrons that have passed through the electron transport layer. The light emitted from the light emitting unit 12 is reflected by the negative electrode 16 and then transmitted through the positive electrode 15 and the glass substrate 10 or directly transmitted through the positive electrode 15 and the glass substrate 10. Is done. Thereby, on the surface side of the glass substrate 10, light is emitted from a linear (band-shaped) light emitting region A having a predetermined width substantially corresponding to the light emitting portion 12.

  The optical member 3 is configured with a light guide 20 made of a light transmissive material such as a transparent resin material as a center. The light guide unit 20 is formed of a long member extending along the light emitting unit 12, and an incident surface 21 for incident radiation light from the light emitting unit 12 is provided on the side facing the glass substrate 10. Have. As shown in FIGS. 1 and 2, the incident surface 21 is formed to have a longer length in the longitudinal direction and a shorter direction than the light emitting portion 12. Then, the incident surface 21 is fixed to the region including the light emitting region A on the glass substrate 10 via the transparent adhesive 5, so that the light from the light emitting unit 12 is received in the light guide unit 20. Incident. In this case, in order to reduce the loss of light incident on the optical member 3 side from the glass substrate 10 side, the transparent adhesive 5 having a refractive index close to that of the optical member 3 and the glass substrate 10 is used. It is desirable that

  Further, in the optical member 3, a cylindrical lens portion 22 is integrally formed of the same light transmissive material as that of the light guide portion 20 on the emission side of the light guide portion 20 facing the entrance surface 21. As shown in FIGS. 1 and 3, the cylindrical lens portion 22 is, for example, a lens curved surface having a substantially arc shape along the short direction of the optical member 3 (that is, the direction orthogonal to the extending direction of the light guide portion 20). 22a. As shown in FIG. 4A, the cylindrical lens unit 22 mainly includes a narrow angle in which the radiation angle in the short direction of the light guide unit 20 is less than a predetermined angle out of the light incident on the light guide unit 20. The light radiated at is condensed at the focal point F by refraction to form linear illumination light.

  Here, as shown in FIG. 3, the top portion of the cylindrical lens portion 22 is the most convex portion of the optical member 3, and in this embodiment, the top portion of the cylindrical lens portion 22 extends from the incident surface 21 of the light guide portion 20. For example, the height T is about T = 7 mm. Further, the distance from the top of the cylindrical lens unit 22 to the focal point F is set so as to substantially match the irradiation distance D from the linear illumination device 1 to the irradiation object 100. In other words, the shape of the lens curved surface 22a of the cylindrical lens portion 22 is designed based on the irradiation distance D.

  Further, in the optical member 3, the reflective optical parts 23 are integrally formed on both sides of the light guide part 20 in the short direction by the same light transmissive material as the light guide part 20. For example, as shown in FIG. 3, the reflecting optical unit 23 includes a side surface 24 that widens from the base side to the front end side of the optical member 3, a front end portion of the side surface 24, and a lens curved surface 22 a of the cylindrical lens unit 22. And a front end face 25 continuous with the base. In the present embodiment, the side surface 24 is constituted by a curved surface defined by, for example, a high-order polynomial approximation curve, and totally reflects light guided into the reflective optical unit 23 from the light guide unit 20 side. It functions as a reflecting surface that leads to the front end face 25 side. Further, the front end face 25 has a function as an emission face for emitting the light totally reflected by the side face 24 to the outside. Here, in order to effectively function the side surface 24 as a reflecting surface, the polynomial approximate curve that defines the shape of the side surface 24 is optimized based on experiments, simulations, and the like. Then, by optimizing the shape of the side surface 24 in this way, for example, as shown in FIG. 4B, the reflection optical unit 23 is incident on the light guide unit 20 through the incident surface 21. Among them, predetermined light emitted outside the optical path to the cylindrical lens portion 22 is totally reflected by the side surface 24 and guided to the front end surface 25, and is emitted from the front end surface 25 toward the focal point F.

  As shown in FIG. 1, in the frame body 4, a pair of wall portions 30 extending in the longitudinal direction of the optical member 3 and a pair of wall portions 31 extending in the short direction of the optical member 3 are integrally joined. It is comprised with the substantially square tube-shaped member made. The frame body 4 is disposed on the glass substrate 10 and surrounds the periphery of the optical member 3 by the wall portions 30 and 31.

  Here, as shown in FIG. 3, the front end portions of the wall portions 30 and 31 protrude forward from the front end surface 25 of the reflective optical portion 23. More specifically, in the present embodiment, the height of each wall 30, 31 is set to a height equivalent to the height T of the optical member 3. The front end portion protrudes to a position equivalent to the top portion of the cylindrical lens portion 22. In addition, among the wall portions 30 and 31 constituting the frame body 4, at least the wall portions 30 extending in the longitudinal direction are made of a reflecting member whose inner surface is mirror-finished. Thereby, the frame 4 (wall part 30) forms the reflective surface 32 continuously extended to the side surface 24 on the output side of the reflective optical part 23. And the reflective surface 32 is light radiated | emitted out of the optical path to the cylindrical lens part 22 among the light which injected into the light guide part 20 via the incident surface 21, for example, as shown in FIG.4 (b). In addition, a part of the light emitted from the front end face 25 without being reflected by the side face 24 of the reflection optical unit 23 is guided to the focal point F by reflection.

  According to such an embodiment, the light emitting unit 12 of the light source 11 is formed in a strip shape extending linearly, and the optical member 3 that converts the emitted light from the light emitting unit 12 into linear light is used as the light emitting unit. 12 on the opposite side of the incident surface 21, a cylindrical lens unit 22 formed integrally with the light guide 20 on the opposite side of the incident surface 21, and both sides of the light guide 20 in the short direction. And a reflection optical part 23 formed integrally, and further, a reflection surface 32 extending continuously from the side surface 24 is provided on the output side of the reflection optical part 23 by the frame 4 surrounding the optical member 3. Thus, it is possible to efficiently use the light emitted from the light source 11 to form linear light with high illuminance without luminance unevenness.

  That is, by configuring the light source 11 using a surface light source such as an organic EL, continuous light can be supplied to the optical member 3, and luminance unevenness can be suitably reduced. In this case, among the light emitted from the light emitting unit 12 of the light source 11 and incident on the light guide unit 20, light that radiates mainly at a narrow angle with a short-side radiation angle less than a predetermined angle is linearly formed by the cylindrical lens unit 22. And condensing mainly the light radiated at a wide angle with a short-angle radiation angle of a predetermined angle or more at the focal point F of the cylindrical lens unit 22 by total reflection at the side surface 24 of the reflection optical unit 23, Light emitted from the light emitting unit 12 can be efficiently used as linear illumination light. Further, a part of the light emitted from the front end face 25 without being reflected by the side face 24 of the reflection optical unit 23, which is mainly emitted in a wide angle whose emission angle in the short direction is a predetermined angle or more, is reflected on the reflection surface 32. By reflecting the light and guiding it to the focal point F, it is possible to further improve the utilization efficiency of the light emitted from the light emitting unit 12. Accordingly, it is possible to realize linear illumination light with high illuminance by using light emitted from the light emitting unit 12 without waste as linear illumination light (see a solid line in FIG. 5). In FIG. 5, the two-dot chain line indicates the illuminance distribution of the illumination light when the optical member 3 and the frame body 4 (reflection surface 32) are not used.

  In this case, the height of the frame 4 is set to a height substantially equal to the height T of the optical member 3, and the projection amount of the reflecting surface 32 is limited with the top of the cylindrical lens portion 22 as a limit. The radiated light from the light emitting unit 12 can be effectively used without increasing the size of the illumination device 1. Further, by limiting the amount of protrusion of the reflecting surface 32, the ratio of the light collected at the focal point F via the cylindrical lens unit 22 is relatively increased, so that the light distribution control by the cylindrical lens unit 22 and the optical system therefor are controlled. Design can be made easy.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, in the linear illumination device 1 of the present embodiment, the distal end portion of the frame body 4 extends forward from the top portion of the cylindrical lens portion 22 that is the most convex portion of the optical member 3. Thus, the effective area of the reflecting surface 32 continuous with the side surface 24 of the reflecting optical unit 23 is enlarged forward.

  Further, as the front end of the frame 4 extends forward from the top of the cylindrical lens portion 22, the irradiation distance D of the linear illumination device 1 when mounted on a copying machine or the like is the frame 4 It is set with reference to the tip part.

  In addition, in order to arrange the focal point F of the cylindrical lens unit 22 that is relatively retracted by the extension of the frame 4 in the vicinity of the irradiation target 100, the cylindrical lens unit 22 of the present embodiment has an in-focus distance of the irradiation distance D. The lens curved surface 22a and the like are optimized so as to be longer (see FIGS. 6 and 7A). Furthermore, in order to guide the reflected light from the side surface 24 of the reflecting optical unit 23 to the focal point F, a polynomial approximation curve that defines the shape of the side surface 24 is optimized based on experiments, simulations, and the like (FIGS. 6 and 7 ( b)).

  According to such a configuration, by extending the reflecting surface 32, for example, as shown in FIG. 7B, the cylindrical lens unit out of the light incident on the light guide unit 20 through the incident surface 21. The light emitted from the front end face 25 without being reflected by the side face 24 of the reflection optical unit 23 is efficiently guided to the focal point F by reflection. it can. Accordingly, it is possible to realize linear illumination light with high illuminance by using light emitted from the light emitting unit 12 without waste as linear illumination light (see a solid line in FIG. 8). In FIG. 8, the alternate long and short dash line indicates the illuminance distribution of the illumination light when the frame 4 (reflecting surface 32) is not used, and the two-dot chain line uses the optical member 3 and the frame 4 (reflecting surface 32). The illuminance distribution of the illumination light when not present is shown.

  Here, when the frame body 4 is projected forward as in the present embodiment, a sufficiently long reflecting surface 32 can be secured in front of the front end surface 25 of the reflecting optical unit 23. It is also possible to improve the degree of concentration of the reflected light at the focal point F by configuring it with a predetermined curved surface.

  In this case, for example, as shown in FIG. 9, the shape of the reflecting surface 32 can be defined according to a polynomial approximation curve that defines the side surface 24 of the reflecting optical unit 23, and the reflecting surface 32 integral with the side surface 24 can be formed. It is.

  Further, in consideration of the refraction of the radiated light at the front end face 25 of the reflection optical unit 23, in order to further improve the degree of condensing light at the focal point F, for example, as shown in FIG. It is also possible to define the shape of In this case, for example, of the two focal points f1 and f2 defining the ellipse, one focal point f1 coincides with the focal point F of the cylindrical lens unit 22, and the other focal point f2 is set in consideration of refraction at the front end face 25. By setting the position offset forward of the light emitting unit 12, the degree of light collection at the focal point F by the reflecting surface 32 can be improved (see FIG. 11).

  DESCRIPTION OF SYMBOLS 1 ... Linear illuminating device, 2 ... Light source unit, 3 ... Optical member, 4 ... Frame, 5 ... Transparent adhesive, 10 ... Glass substrate, 11 ... Light source (surface light source), 12 ... Light emission part, 15 ... Positive electrode , 15a ... terminal part, 16 ... negative electrode, 16a ... terminal part, 20 ... light guide part, 21 ... incident surface, 22 ... cylindrical lens part, 22a ... curved lens surface, 23 ... reflective optical part, 24 ... side face, 25 ... Front end face, 30 ... wall part (reflective member), 31 ... wall part, 32 ... reflective surface, 100 ... irradiation target

Claims (3)

A surface light source in which the light emitting part is formed in a strip shape;
A light guide portion having an incident surface extending opposite the light emitting portion;
A cylindrical lens unit that is integrally formed with the light guide unit on the opposite side of the incident surface, and that condenses light incident on the light guide unit into a linear shape by refraction;
The light guide unit is integrally formed on both sides in the short-side direction, and the light emitted from the light path to the cylindrical lens unit out of the light incident on the light guide unit is totally reflected on the side surface of the cylindrical lens unit. A reflective optical unit that emits toward the focal point;
A linear illumination device comprising: a reflection member that forms a reflection surface continuously extending on the side surface on an emission side of the reflection optical unit.   The linear illumination device according to claim 1, wherein the amount of protrusion of the reflecting surface is set with the top of the cylindrical lens portion as a limit.   The linear illumination device according to claim 1, wherein the reflection surface is configured by a curved surface protruding forward from the cylindrical lens portion.

Images