JP2012099387A - Optical element and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element which does not require a time and effort for manufacture while it can emit light by inclining greatly to an optical axis of a light source, and to provide a lighting system using the same.SOLUTION: An emitting face 11c is inclined to a face orthogonal to the optical axis Z of the light source 12 and a blaze shape 11g is formed. Thus, even when light distribution characteristics which are greatly inclined to the optical axis Z of the light source 12 are given, the inclination angles of the emitting face 11c are suppressed by combined use with the blaze shape 11g to make its structure compact. Further, compared with a case where it is used independently, the level difference of the blaze shape 11g can be made small, and since the total reflection is reduced, the light utilization efficiency can be increased.

Description

  The present invention relates to an optical element and an illuminating device, and more particularly to an illuminating device suitable for illuminating a signboard, a wall surface, and the like, and the optical element.

  When illuminating a self-supporting signboard, extend the column in the horizontal direction from the upper end of the signboard, illuminate the signboard by emitting light from the projector attached to the tip, or emit light from the projector installed on the ground The sign is illuminated. However, as a problem when illuminating a conventional signboard, when a general projector is used, the light distribution is symmetric, so the light spreads to the opposite side of the signboard, so that the projector can be illuminated efficiently and brightly It is necessary to incline to the signboard side. When such an installation method is taken, since a large-sized signboard cannot sufficiently illuminate the upper part of the signboard, a plurality of projectors are required, and waste is increased.

  On the other hand, as shown in Patent Documents 1 and 2, it is conceivable to illuminate the signboard using an optical element having a light distribution characteristic inclined with respect to the optical axis.

Japanese translation of PCT publication No. 2002-528861 JP 2008-103300 A

  Here, Patent Document 1 discloses an optical element that emits light in a direction inclined with respect to the optical axis of a light source by forming a blazed shape on an emission surface. According to the optical element of Patent Document 1, the light distribution characteristic with a narrow range of the emitted light or the light distribution characteristic with a small bending angle with respect to the optical axis of the light source can be realized relatively easily due to the blaze shape provided on the emission surface. It is difficult to obtain a light distribution characteristic having a certain extent necessary for lighting of a signboard. Further, if it is attempted to increase the bending angle with respect to the optical axis of the light source, there is a problem that total reflection tends to occur on the exit surface and the light use efficiency is lowered.

  On the other hand, Patent Document 2 discloses an optical element that has an incident surface, a reflecting surface, and an output surface that are inclined with respect to the optical axis of the light source, and emits light in a direction inclined with respect to the optical axis of the light source. . According to the optical element of Patent Document 2, since there is no blazed shape on the exit surface, it is possible to ensure the utilization efficiency because total reflection hardly occurs when the tilt angle is small, but due to its configuration, with respect to the optical axis of the light source There is a problem that light cannot be emitted with a large tilt. Moreover, when forming the optical element of patent document 2 by shaping | molding, there also exists a problem of how to release.

  The present invention has been made in view of such problems of the prior art, and uses an optical element that does not require a lot of manufacturing, although it can emit a light beam with a large inclination with respect to the optical axis of the light source. An object is to provide a lighting device.

The optical element according to claim 1 is an optical element for a lighting device including a light source and an optical element disposed on at least a light emission side of the light source,
An incident surface on which light from the light source is incident;
A reflective surface that reflects at least a portion of the light incident from the incident surface;
An exit surface for emitting light incident from the entrance surface;
The exit surface is inclined with respect to a surface orthogonal to the optical axis of the light source, and a blazed shape is formed.

  In order to emit the incident light at an angle greatly inclined with respect to the optical axis of the light source, the emission surface may be inclined largely with respect to the optical axis. However, this increases the inclination angle of the exit surface, leading to an increase in the size of the optical element. On the other hand, when a blazed shape is provided on the exit surface, by increasing the step, incident light can be emitted at an angle greatly inclined with respect to the optical axis of the light source, but it becomes difficult to mold the optical element, Moreover, it becomes easy to totally reflect on the exit surface, and the efficiency is lowered.

  On the other hand, according to the present invention, the emission surface is inclined with respect to a plane orthogonal to the optical axis of the light source and has a blazed shape, so that it is greatly inclined with respect to the optical axis of the light source. Even when the light distribution characteristic is given, the combined use with the blazed shape suppresses the inclination angle of the exit surface to make the structure compact, and the step of the blazed shape can be reduced as compared with the case of using it alone. The use efficiency of light can be increased by reducing reflection.

  According to a second aspect of the present invention, the optical element according to the first aspect of the present invention is the most within a range of 25 ± 5 degrees in absolute value with respect to a predetermined plane including the optical axis of the light source, the optical axis direction being 0 degrees. It is characterized by having a strong peak. Thereby, it becomes suitable for using for illumination of a signboard etc.

  According to a third aspect of the present invention, the optical element according to the second aspect of the present invention is the second surface in the range of 60 to 80 degrees in absolute value with the optical axis direction being 0 degrees on a predetermined surface including the optical axis of the light source. Has a strong peak. Thereby, the lower part of a signboard etc. can be illuminated brightly.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the incident surface has a rotationally symmetric surface with respect to the optical axis of the light source. Thereby, an optical element that can be easily molded can be provided.

  An optical element according to a fifth aspect of the present invention is the optical element according to any one of the first to fourth aspects, wherein the reflecting surface is a paraboloid, an aspherical surface, or a Bezier having an axis inclined with respect to the optical axis of the light source. It is a part of a curved surface composed of a curve / spline curve. Thereby, incident light can be efficiently reflected toward the exit surface.

  A lighting device according to a sixth aspect uses the optical element according to any one of the first to fifth aspects.

  The illumination device of the present invention includes a light source and an optical element. The light source according to the present invention is preferably an LED (Light Emitting Diode), but may be another light source such as an incandescent bulb.

  The optical element is preferably formed by molding a mold, and is disposed at least on the light emission side of the light source. An incident surface on which emitted light from the light source is incident; a reflective surface that reflects at least part of the incident light; It has an emission surface for emitting incident light to the outside. Further, the optical element and the light source may be in contact or non-contact.

  A blaze shape is formed on the emission surface. The blaze shape means that the cross-sectional shape of the optical element is a sawtooth shape, and more specifically, a periodic shape composed of a slope and a step surface. The exit surface forming the blazed shape is preferably a flat surface, but may have a large radius of curvature. The exit surface and the blazed shape are preferably inclined in the same direction, but the inclination direction may be different within ± 30 degrees.

  The light emitted from the emission surface preferably has the strongest peak in the range of 25 ± 5 degrees in absolute value with the optical axis of the light source being 0 degree. Moreover, it is preferable that the width of this peak is somewhat large.

  The light emitted from the emission surface preferably has a second highest intensity peak in the range of 60 to 80 degrees in absolute value with the optical axis of the light source being 0 degrees.

  The incident surface preferably has a rotationally symmetric surface with respect to the optical axis of the light source. Such an incident surface may be inclined with respect to the optical axis.

  The optical element is preferably made of glass or plastic. Examples of the plastic constituting the optical element include thermoplastics such as cyclic polyolefin and polycarbonate, thermosetting plastics, photocurable plastics, and UV curable plastics. When a thermoplastic such as cyclic polyolefin or polycarbonate is used, it can be more preferably used because it can be produced by injection molding and the production cost can be greatly reduced. In particular, polycarbonate can be used more preferably.

  ADVANTAGE OF THE INVENTION According to this invention, although it can incline largely with respect to the optical axis of a light source, and can radiate | emit a light ray, the optical element which does not require a manufacturing effort, and an illuminating device using the same can be provided.

It is sectional drawing which cut | disconnects and shows the illuminating device 10 concerning this Embodiment in the cross section containing the optical axis Z of a light source. It is a figure which expands and shows the arrow II part of the structure of FIG. It is a figure which shows the illumination area | region in the state where the illuminating device 10 concerning this Embodiment is set | placed on the origin O, and the lowest position of an output surface touches a YZ surface. It is a figure which shows the light distribution characteristic in the optical element 11 of this Embodiment, takes light intensity in the radial direction, and takes the angle from the optical axis in the circumferential direction. It is sectional drawing similar to FIG. 1 of the illuminating device 10 'concerning a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of the illumination device 10 according to the present embodiment cut along a cross section including the optical axis Z of the light source. In the drawing, the position where the left end LE of the emission surface becomes the highest, The right end RE is the lowest position. FIG. 2 is an enlarged view of an arrow II part of the configuration of FIG. The illumination device 10 according to the present embodiment includes an optical element 11 and a light source 12. The optical axis Z refers to the central axis of the light emitted from the light source 12.

  The optical element 11 has a substantially truncated conical shape, and protrudes horizontally in a bowl shape between the recess 11a covering the light source 12, the outer peripheral surface 11b, the output surface 11c, and the outer peripheral surface and the output surface. And a flange portion 11d. The lower end of the optical element 11 is preferably in contact with a substrate (not shown) on which the light source 12 is formed. The recess 11a has a side incident surface 11e that is rotationally symmetric with respect to the optical axis Z, and an upper surface incident surface 11f that is orthogonal to the optical axis Z. When the optical element 11 is formed from a mold, it is desirable that the side incident surface 11e is inclined with respect to the optical axis Z at an angle that ensures a draft angle. At this time, the mold release direction is parallel to the optical axis Z direction.

  The outer peripheral surface 11b constituting the reflecting surface is a part of a paraboloid formed around an axis inclined with respect to the optical axis Z. The inflection point side of the paraboloid (the lower end side of the optical element 11). ) Is cut out. The outer peripheral surface 11b may be a part of a curved surface formed of an aspherical surface, a Bezier curve or a spline curve.

  The emission surface 11c is inclined with respect to a surface orthogonal to the optical axis Z. Further, a fine blazed shape 11g as shown in FIG. 2 is formed on the emission surface 11c. The blaze shape 11g is a structure formed by periodically repeating a unit composed of an inclined surface 11h and a step surface 11i that are inclined in accordance with the inclination direction (left and right direction in FIG. 1) of the emission surface. As an example, the inclination angle θ of the inclined surface 11h with respect to the emission surface 11c is 13 degrees. The width a of the slope 11h is preferably larger than the height b of the step surface 11i.

  The flange portion 11d is used when the optical element 11 is attached to a support member (not shown).

  Part of the light emitted from the light source 12 is incident on the optical element 11 from the side surface incident surface 11e, and the rest is incident on the upper surface incident surface 11f. A part of the light incident on the optical element 11 is reflected by the outer peripheral surface 11b and travels to the exit surface 11c, and the rest travels directly to the exit surface 11c.

  Since the exit surface 11c is tilted, the light beam exits so as to tilt to the left in FIG. Further, since the blazed shape 11g is provided on the emission surface 11c, the light beam is emitted so as to be inclined further to the left side with respect to the optical axis Z due to the refraction.

  According to the present embodiment, the emission surface 11c is inclined with respect to the surface orthogonal to the optical axis Z of the light source 12, and the blazed shape 11g is formed. Even when a light distribution characteristic which is greatly inclined is given, the inclination angle of the exit surface 11c is suppressed by using the blazed shape 11g in combination, so that the stepped portion of the blazed shape 11g can be reduced as compared with the case where it is used alone. Therefore, the light utilization efficiency can be increased by reducing total reflection.

  FIG. 3 is a diagram illustrating an illumination region in a state where the illumination device 10 according to the present embodiment is placed at the origin O and the lowest position of the emission surface faces the negative side (left side) of the X axis. FIG. 4 is a diagram showing light distribution characteristics in the optical element 11 of the present embodiment. In FIG. 4, graph A shows the characteristics in the XZ plane, graph B shows the characteristics in the plane including the Z axis and extending in the intermediate direction (45-degree direction) of the X axis and the Y axis, and graph C shows the YZ The characteristic in the surface is shown.

  In the state where the optical axis is overlapped in the Z direction (0 degree), as shown in FIG. 4, the first peak PK1 having the strongest light intensity is generated at the position of −22 degrees on the XZ plane, and −67 degrees. A second peak PK2 having the second highest light intensity is generated at the position. Since it has such a light distribution characteristic, the illuminating device 10 is suitable for illuminating a signboard or the like placed on the YZ plane from below. As shown in FIG. 4, in this embodiment, the peak intensity on the XZ plane is larger than the peak intensity on the YZ plane, that is, a strong directivity that suppresses the emission of light rays in directions other than the signboard. I understand that I have it.

  FIG. 5 is a cross-sectional view similar to FIG. 1 of a lighting device 10 ′ according to a modified example, but is reversed left and right. In the present modification, the lowest side of the emission surface 11c in the embodiment shown in FIG. 1 is the right side, and the taper surface having an angle α around the axis S that extends parallel to the optical axis Z and extends in the direction perpendicular to the paper surface. It has a shape obtained by scraping off a part of the outer peripheral surface. Thereby, the outer peripheral surface 11b consists of a part 11j of a paraboloid and a tapered surface 11k having a concave shape when viewed in the optical axis direction. It is preferable that α = 30 degrees. Since other configurations are the same as those of the above-described embodiment, the description thereof is omitted.

  The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is.

DESCRIPTION OF SYMBOLS 10 Illuminating device 11 Optical element 11a Recessed part 11b Outer peripheral surface 11c Outgoing surface 11d Flange part 11e Side surface incident surface 11f Upper surface incident surface 11g Blaze shape 11h Slope 11i Stepped surface 11j Part of outer peripheral surface 11k Tapered surface 12 Light source PK1 First peak PK2 First 2 peaks S axis

Claims (6)

An optical element for a lighting device, comprising: a light source; and an optical element disposed on at least a light emission side of the light source,
An incident surface on which light from the light source is incident;
A reflective surface that reflects at least a portion of the light incident from the incident surface;
An exit surface for emitting light incident from the entrance surface;
The optical element is characterized in that the emission surface is inclined with respect to a surface orthogonal to the optical axis of the light source and has a blazed shape.   The light emitted from the emission surface has a peak with the strongest intensity within a range of 25 ± 5 degrees in absolute value with the optical axis direction as 0 degree on a predetermined surface including the optical axis of the light source. The optical element according to claim 1.   The light emitted from the emission surface has a second highest intensity peak in a range of 60 to 80 degrees in absolute value with the optical axis direction as 0 degrees on a predetermined surface including the optical axis of the light source. The optical element according to claim 2.   The optical element according to claim 1, wherein the incident surface has a rotationally symmetric surface with respect to the optical axis of the light source.   5. The reflection surface according to claim 1, wherein the reflection surface is a paraboloid having an axis inclined with respect to the optical axis of the light source, an aspheric surface, and a part of a curved surface including a Bezier curve / spline curve. An optical element according to any one of the above.   An illumination device using the optical element according to claim 1.