JP2012212574A - Optical lens, and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical lens used for a tunnel lighting device, which can restrain light unevenness by controlling distribution of light emitted from a light source in a designated direction.SOLUTION: The optical lens 3 includes an incident surface 31 where the light emitted from the light source is incident, and an emitting surface 32 for emitting the light incident to the incident surface 31. The emitting surface 32 takes on a convex outline shape, and a cross-section shape of the emitting surface 32 is made of a plurality of curved lines C1, C2 having different curvature radii. The first curved line C1 having a larger curvature radius is arranged at a location facing to a center part of the incident surface 31, and the second curved lines C2 having a smaller curvature radius each are respectively arranged on both sides of the first curved line C1. According to this structure, part of light from the portion covered with the first curved line C1 of the emitting surface 32 is restrained, and part of light from the portion covered with the second curved lines C2 of the emitting surface 32 can be accelerated, and thus, emitted light from the optical lens 3 can be made uniform.

Description

  The present invention relates to an optical lens that controls light distribution of light emitted from a light source, and an illumination device using the same.

  Light emitting diodes (hereinafter referred to as LEDs) are capable of emitting light with low power and high luminance, and are used as light sources for various electric devices such as displays and lighting equipment. In recent years, blue LEDs have been put into practical use in addition to red LEDs and green LEDs, and various light colors can be emitted by combining these RGB three-color LEDs. In addition, so-called white LEDs in which blue LEDs and yellow phosphors are combined are used in other fields.

  LEDs are used as light sources for traffic lights and various display lamps because they have a longer life than conventional light sources such as fluorescent lamps and require less replacement and maintenance. Moreover, what uses LED as a light source of road illuminations, such as a highway and a general road, is known (for example, refer patent document 1). In the illuminating device described in Patent Document 1, by using an optical lens having first and second converging parts for converging light from LEDs and a diverging part for bridging them, it can be applied to a wide range of roads. Light is irradiated.

  By the way, in the technical field of the tunnel illumination device, as shown in FIG. 14, a plane parallel to the direction in which the vehicle or the like travels is called a B section, and a plane orthogonal to the B section is called an A section. In the tunnel lighting device, it is desired that the light irradiation range in the direction along the B cross section is wide. On the other hand, in the direction along the A cross section, it is only necessary to illuminate a predetermined range of the road surface, and the luminance reduction is suppressed. In order to achieve this, it is preferable that the light irradiation range be limited to some extent.

  Therefore, by using a semi-elliptical optical lens 103 as shown in FIGS. 15A and 15B, the light irradiation range in the A cross-sectional direction and the B cross-sectional direction can be controlled. A light distribution curve of an illuminating device using the optical lens 103 is shown in FIG. By using the optical lens 103, light can be irradiated over a wide range in the direction along the B cross section, and light can be irradiated over a narrow range compared with the B cross section in the direction along the A cross section. Can do.

JP 2010-524170 A

  However, when the optical lens 103 is used, the light distribution curve along the A section has a large bulge at a light distribution angle of 10 to 20 ° (region indicated by L1 in FIG. 16), while the light distribution angle is 30 to 40. Swelling at ° is small (region indicated by L2 in the figure). According to such a light distribution, the luminance at the center of the lane increases, but the luminance near the road shoulder decreases, the luminance of the entire road surface in the tunnel becomes non-uniform, and there is a possibility of causing light unevenness. Further, a part of the light along the A cross section leaked from the side surface of the optical lens 3 (region indicated by L3 in the figure), and the light use efficiency was lowered.

  In the illumination device described in Patent Document 1, light is evenly irradiated over a wide range from the optical lens. However, unevenness of light may occur on the irradiation surface depending on the distance, arrangement, and the like.

  The present invention has been made in view of the above problems, and is mainly used for tunnel illumination. Light distribution from a light source is controlled in a predetermined direction to suppress light unevenness on an irradiation surface (road surface). It is an object of the present invention to provide an optical lens that can be used and an illumination device using the same.

  In order to solve the above-described problems, an optical lens according to the present invention has an incident surface on which light from a light source is incident and an output surface that emits light incident on the incident surface, and emits light from the light source. An optical lens that diffuses and emits, wherein the exit surface has a convex outer shape, and a cross-sectional shape of the exit surface in a plane including a normal passing through a central portion of the entrance surface has a radius of curvature. A first curve having a large curvature radius is arranged at a position facing the central portion of the incident surface, and the radius of curvature is larger than that of the first curve on both sides of the first curve. A small second curve is arranged, respectively.

  In the optical lens, it is preferable that a boundary between the first curve and the second curve is smoothly continuous.

  In the optical lens, it is preferable that an end portion of the second curved line that is continuous with the incident surface is bent toward a center portion of the incident surface.

  In the optical lens, it is preferable that the incident surface has a concave portion at a central portion thereof.

  In the optical lens, it is preferable that a cross-sectional shape of the recess in a plane orthogonal to the one plane is a curve having a different trajectory from a curve forming a cross-sectional shape of the exit surface in the plane.

  In the optical lens, it is preferable that the exit surface is subjected to glare suppression processing in both end regions in a plan view orthogonal to the one plane.

  It is preferably used for the optical lens and the illumination device.

  According to the present invention, the cross-sectional shape of the exit surface is constituted by the first curve having a large radius of curvature and the second curves arranged on both sides of the first curve. A part of the light from the simulated place is suppressed. On the other hand, since a part of the light from the location imitated by the second curve 2 on the emission surface is promoted, unevenness of light on the irradiation surface can be suppressed.

1 is a side sectional view of an optical lens and an illumination device using the same according to an embodiment of the present invention. (A) is the back perspective view seen from the B section (refer to Drawing 14, the following same) of the tunnel of the optical lens, and (b) is the back view. The side view along the A cross section of the tunnel of the optical lens. The side view along the A section of the optical lens, and a partial enlarged view. (A) and (b) are the side sectional views in the A section of the optical lens, and (c) is the back view along the B section. The side view along the B cross section of the same optical lens. The partial enlarged top view along the B cross section of the same optical lens. The back perspective view seen from the B section of the tunnel of the optical lens. The figure which shows the structure of the same optical lens, and the light distribution curve by it. The figure which shows the other structure of the same optical lens, and the light distribution curve by it. (A) is a sectional side view along the A section showing another configuration of the optical lens, and (b) is a diagram showing a light distribution curve thereby. (A) is the side view along the B cross section of the optical lens which concerns on a modification, (b) is the side view seen from the slightly B cross section. The schematic diagram which shows the example using the illuminating device provided with the optical lens which concerns on a modification. The perspective view for demonstrating the A cross section and B cross section in a tunnel. (A) is a top view of the conventional optical lens, (b) is the perspective view. The figure which shows the light distribution curve by the illuminating device provided with the conventional optical lens.

  An illumination device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the illumination device 1 of the present embodiment holds a light source unit 2 having a light source 20, an optical lens 3 disposed on the light source unit 2, and the light source unit 2 and the optical lens 3. Holding plate 4. In addition, although the illuminating device 1 can be used as various illuminating devices, such as a street lamp, the example utilized as an illuminating device for tunnels is demonstrated below. Further, as described above, in the tunnel, a plane parallel to the traveling direction of the vehicle or the like is referred to as a B section, and a plane orthogonal to the B section is referred to as an A section. In this example, as shown in FIG. 1, the light source unit 2 and the optical lens 3 are formed so as to have a longitudinal direction and a lateral direction, and the longitudinal direction thereof is arranged along the B cross section of the tunnel. The configuration will be described.

  In addition to the light source 20, the light source unit 2 includes a base member 21 on which the light source 20 is mounted, and an attachment frame 22 to which the base member 21 is attached. In the light source 20, a plurality of LED chips (not shown) are arranged in a matrix, and the wavelength conversion member containing a phosphor is coated on the light emission surface of the LED chips. For example, a GaN blue LED chip that emits blue light is used as the LED chip. As the wavelength conversion member, for example, a translucent resin such as a silicone resin containing a YAG yellow phosphor is used. The base member 21 includes a concave portion formed by digging in a central region thereof, and a wiring pattern (not shown) electrically connected to the anode electrode and the cathode electrode of the LED chip on the bottom surface of the concave portion. This wiring pattern is connected to an electrode extraction portion (not shown) provided on the back side of the base member 21. The base member 21 is fixed to the mounting frame 22 by screwing or bonding. The mounting frame 22 has a storage portion (not shown) for storing the wiring connected to the electrode extraction portion of the base member 21 at the mounting position of the base member 21 and a wiring port (not shown) for taking out the wiring out of the lighting device 1. ). Moreover, the screw | thread for inserting the screw | thread 51 which fixes the light source unit 2 to the holding plate 4 in the peripheral part of the attachment position of the base member 21 of the attachment frame 22, in this example, the both ends of the longitudinal direction of the said peripheral part. A hole 23 is formed.

  The optical lens 3 has an incident surface 31 on which light from the light source 20 is incident, and an output surface 32 that emits light incident on the incident surface 31. The exit surface 32 has a convex outer shape so that the light incident on the entrance surface 31 can be diffused and emitted. The entrance surface 31 and the exit surface 32 constitute the lens body 30 of the optical lens 3. The lens body 30 is formed so that the width in the B cross-sectional direction is larger than the width in the A cross-sectional direction. In addition, the optical lens 3 including the attachment leg part 35 mentioned later is formed from the material excellent in translucency, such as an acrylic resin, a polycarbonate resin, or glass.

  As shown in FIGS. 2A and 2B, a light source housing portion 33 that houses the base member 21 of the light source unit 2 is dug in the incident surface 31, and faces the light source 20 in the center portion of the light source housing portion 33. A recessed portion 34 is further dug and formed at the place to be formed. The light source storage portion 33 is formed with a recess 36 for storing the screw head of the screw 51.

  At both end portions of the lens body 30 in the longitudinal direction, attachment leg portions 35 are respectively extended. These mounting legs 35 are provided alternately in the lateral direction of the lens body 30. The mounting leg portion 35 includes an extending portion 35a that extends horizontally from the lens body portion 30 and a vertical portion 35c that connects the extending portion 35a to the lens body portion 30. The extending portion 35a and the light source housing The part 33 is formed so as to have a stepped structure through the vertical part 35b. In addition, the vertical part 35b is cut obliquely so that the center of the light source storage part 33 is wide according to the shape of the light source unit 2 (particularly the mounting frame 22). Further, the height of the perpendicular portion 35 b is formed so as to correspond to the length in the longitudinal direction of the mounting frame 22 and the thickness of the mounting frame 22. A screw hole 37 for inserting a screw 52 for fixing the optical lens 3 to the holding plate 4 is formed in the extending portion 35a. The holding plate 4 includes fixing holes 41 and 42 through which the screws 51 and 52 are inserted, and an arbitrary holding structure (not shown) for fixing to the side wall or ceiling of the tunnel.

  As shown in FIG. 3, the optical lens 3 has a plane including the normal line NL passing through the central portion of the incident surface 31, and in this example, the cross-sectional shape of the exit surface 32 in the A cross section of the tunnel has a plurality of different curvature radii. Of the curves C1 and C2. In addition, a first curve C1 having a large curvature radius is disposed at a position facing the central portion of the incident surface 31, and a second curve C2 having a curvature radius smaller than that of the first curve C1 is provided on both sides of the first curve C1. Are arranged respectively.

  The 1st curve C1 and the 2nd curve C2 are not necessarily restricted to the circular arc which comprises a part of perfect circle. For example, the first curve C1 is preferably an arc that forms a part of an ellipse whose major axis is the direction of the normal NL. By doing so, the apex portion P4 of the first curve C1 protrudes, so that it is possible to increase the light irradiation in the normal NL direction.

  Since the first curve C1 and the second curve C2 have different radii of curvature and center positions, a slight step as shown in FIG. 4A occurs at the intersection P3. Therefore, as shown in FIG. 4B, it is preferable that the boundary between the curves C1 and C2 having different curvature radii is processed so as to be smoothly continuous by the inverted R-shaped portion M. By so doing, light unevenness caused by the boundary between the curves C1 and C2 can be suppressed, and more natural light distribution control becomes possible.

  An end C2 'that is continuous with the incident surface 31 of the second curve C2 of the optical lens 3 will be described with reference to FIGS. FIG. 5A is an A1 cross section of FIG. 5C, and FIG. 5B is an A2 cross section of FIG. 5C. The end C2 'is preferably bent toward the center of the incident surface 31, as shown in FIG. According to this configuration, of the light incident on the concave portion 34 (incident surface 31), the light incident on the vicinity of the end C2 ′ of the output surface 32 has a large incident angle with respect to the vicinity thereof, and thus is totally reflected at this interface. It becomes easy. Therefore, light passing through the vicinity of the end C2 'and leaking in the short direction of the optical lens 3 is reduced, and the light from the light source 20 can be used efficiently. Such a bent end C2 'may be formed in the optical lens 3 at a position close to the light source 20, that is, in a cross section A1 passing through the central portion in the B cross section shown in FIG. Accordingly, in the optical lens 3 at a position far from the light source 20, that is, in the cross section A2 passing through the end portion of the incident surface 31 in the B cross section shown in FIG. 5C, the end as shown in FIG. The part C2 ′ may not be bent.

  Further, as shown in FIG. 6, the optical lens 3 has a plane orthogonal to one plane including the normal line NL passing through the central portion of the incident surface 31 described above, in this example, the concave portion 34 along the B cross section of the tunnel. The cross-sectional shape is a curve C4 having a different trajectory from the curve C3 that forms the cross-sectional shape of the exit surface 32. That is, the curve C3 that forms the cross-sectional shape of the exit surface 32 is a curve (arc) that forms part of the perfect circle S1, while the curve C4 that forms the cross-sectional shape of the recess 34 forms part of the ellipse S2. It is a curve to do.

  As described above, by providing the concave portion 34 on the incident surface 32, in addition to the light refraction at the emission surface 32, the light refraction at the incident surface 31 (the concave portion 34) is controlled to control the light distribution in more detail. be able to. Further, as described above, the cross-sectional shape of the recess 34 along the B cross-section is formed by the curve C4 having a different trajectory from the curve C3 forming the cross-sectional shape of the emission surface 32, whereby the arrangement in the direction along the B cross-section is made. Light can be controlled. That is, the optical lens 3 can control the light distribution in the direction along the A cross section by the cross sectional shape of the emission surface 32 along the A cross section, and along the B cross section by the cross sectional shape of the recess 34 along the B cross section. The light distribution in different directions can be controlled.

  Here, the shape of the recessed part 34 is demonstrated in detail with reference to FIG.7 and FIG.8. First, an imaginary rotating piece 5 as shown in FIG. The rotating segment 5 is composed of a plurality of curves or ellipses having different radii of curvature. Then, as shown in FIG. 8, the lens body 30 is moved along the surface of the virtual solid 50 obtained by sweeping the rotating segment 5 along the elliptical orbit S <b> 3, and the incident surface 31 (the light source storage unit 33). The outer shell surface of the concave portion 34 is formed by punching from the side.

  9 and 10 show light distribution curves of the illumination device 1 using the optical lens 3 of the present embodiment configured as described above. FIG. 9 shows an optical lens having a step at the boundary between the first curve C1 and the second curve C2 in the cross-sectional shape along the B cross section of the emission surface 32 as shown in FIG. A light distribution curve when 3 is used is shown. 10 uses the optical lens 3 in which the boundary between the first curve C1 and the second curve C2 is smoothly continuous by the inverted R-shaped portion M, as shown in FIG. 4B. The light distribution curve when

  When the conventional optical lens 103 as shown in FIG. 15 is used, as shown in FIG. 16, the bulge at a light distribution angle of 10 to 20 ° is large in the light distribution curve along the A section (same as above). On the other hand, the bulge at a light distribution angle of 30 to 40 ° was reduced (L2 in the figure). Further, a part of the light along the A section leaked to the side of the optical lens 3 (L3 in the figure).

  On the other hand, when the optical lens 3 of this embodiment is used, as shown in FIG. 9, in the light distribution curve along the A cross section, the bulge at a light distribution angle of 10 to 20 ° is reduced (L1 in the figure). On the other hand, the swelling at a light distribution angle of 30 to 40 ° increased (L2 in the figure). Furthermore, light leakage to the side of the optical lens 3 was also suppressed (L3 in the figure).

  Thus, according to the optical lens 3, in the light distribution curve along the A cross section, the light distribution angle of 10 to 20 ° is determined by the portion (see FIG. 3) imitated by the first curve C1 in the emission surface 32. The bulge in can be reduced. That is, the portion imitated by the first curve C1 functions as a narrow angle portion for controlling the light distribution of the emitted light at a narrow angle, and slightly suppresses the luminance of the light distributed at the narrow angle. Moreover, the bulge in the light distribution angle of 30-40 degrees can be enlarged according to the location simulated by the 2nd curve C2 among the output surfaces 32. FIG. That is, the portion imitated by the first curve C1 functions as a wide angle portion for controlling the light distribution of the narrow angle, and promotes the luminance of the light distributed at the wide angle. Thus, by controlling the light distribution using an optical lens having a narrow-angle part and a wide-angle part as the exit surface 32, the illumination device 1 does not have excessively high luminance at the center of the lane in the tunnel, The brightness near the road shoulder does not become too low, and the entire road surface can be irradiated with light uniformly.

  In the light distribution curve shown in FIG. 9, light unevenness due to a step is seen at the boundary between the first curve C1 and the second curve C2 in the region indicated by L2. On the other hand, when the optical lens 3 in which the boundary between the first curve C1 and the second curve C2 is smoothly continued is used, as shown in FIG. The light unevenness in the region indicated by the middle L2 was reduced.

  Next, the fixture evaluation of the illuminating device 1 using the optical lens 3 of this embodiment was performed. In addition, in this instrument evaluation, it is the structure comprised so that the 1st curve C1 and 2nd curve C2 imitating the output surface 32 may continue smoothly, ie, the structure shown to (A) of FIG. The optical lens 3 having the orientation curve shown in FIG. 10 was used. The results are shown in Table 1 below.

  In Table 1 above, U0 (total uniformity) is an index that affects the appearance of an object on the road surface, and is represented by Lmin (roadway minimum partial brightness) / Lr (roadway average road surface brightness). In tunnel illumination, U0 is preferably 0.4 or more. Ul (lane axis uniformity) is an index that determines the degree of discomfort due to light and darkness in the forward direction, and is expressed by Lmin (l) (minimum partial luminance on the lane center line) / Lr (maximum partial luminance on the lane center line). Is done. Ul is preferably 0.6 or more. The Ti value (glare) is an index that affects the glare of light, and the relative threshold value in tunnel illumination is preferably 15% or less (standard value).

  The results shown in Table 1 above met the target orientation in the evaluation at any point of U0 and Ul. On the other hand, with respect to glare, although the target was not satisfied, it was possible to suppress it to a standard value of 15% or less. Further, the illumination rate exceeded the target, and it was shown that the light utilization efficiency is improved by the optical lens 3.

  In FIG. 5A described above, the optical lens 3 in which the end C2 'continuous with the incident surface 31 of the second curve C2 is bent toward the center of the incident surface 31 is shown. Here, as shown in FIG. 11A, the light distribution curve when the optical lens 3 whose end C2 ′ is not bent toward the center of the incident surface 31 is used is shown in FIG. Show. According to this optical lens 3, the light distribution curve of the cross section of FIG. A slightly spreads in the region indicated by L4 in the drawing, but the volume of the region indicated by L5 in the drawing is reduced. As a result, the light incident on the optical lens 3 is slightly radiated to the outside from the vicinity of the end portion C2 ′ of the emission surface 32, so that the light irradiation range is widened, but the luminance with respect to the front direction is increased. Indicates that it has declined. On the other hand, the lowering of the luminance can be suppressed by bending the end C2 'toward the center of the incident surface 31.

  Next, an optical lens according to a modification of this embodiment will be described with reference to FIGS. As shown in FIGS. 12A and 12B, the optical lens 3 according to this modification has a plan view in which the exit surface 32 is orthogonal to one plane including the normal NL passing through the center of the entrance surface 31, that is, When viewed from the B cross section, glare suppression processing is applied to both end regions G thereof. According to this configuration, in the light distribution curve along the B section, it is possible to suppress glare particularly in light distributed at a wide angle.

  For example, as shown in FIG. 13, a driver D who gets on a car traveling in a tunnel T receives light L <b> 1 from the illumination device 1 located in front. However, in this modification, the light L1 is emitted from the emission surface 32 that has been subjected to the glare suppression process, so that it is possible to make it difficult for the driver D to feel discomfort due to glare. On the other hand, since the light L2 is emitted from the emission surface 32 that has not been subjected to the glare suppression process in the direction along the A cross section, the driver D can clearly see the irradiated object in front.

  In addition, this invention is not restricted to the said embodiment, A various deformation | transformation is possible. For example, the pair of second curves C2 disposed on both sides of the first curve C1 on the exit surface of the optical lens 3 only needs to have a radius of curvature smaller than that of the first curve C1, and the second curve C2 The curvature radii of each other do not necessarily coincide with each other. That is, the cross-sectional shape of the emission surface 32 along the A cross section of the tunnel may be symmetrical with respect to the normal line NL. Further, a further curve having a different radius of curvature may be arranged outside the second curve C2.

DESCRIPTION OF SYMBOLS 1 Illuminating device 20 Light source 3 Optical lens 31 Incident surface 32 Outgoing surface 34 Recessed part C1 1st curve C2 2nd curve NL Normal line which passes along the center part of an incident surface

Claims (7)

An optical lens that has an incident surface on which light from a light source is incident and an output surface that emits light incident on the incident surface, and diffuses and emits light from the light source,
The exit surface has a convex outer shape,
A cross-sectional shape of the exit surface in one plane including a normal line passing through the central portion of the entrance surface is composed of a plurality of curves having different curvature radii, and is located at a position facing the center portion of the entrance surface and having a large curvature radius. An optical lens, wherein a first curve is arranged, and a second curve having a radius of curvature smaller than that of the first curve is arranged on both sides of the first curve.   The optical lens according to claim 1, wherein a boundary between the first curve and the second curve is smoothly continuous.   3. The optical lens according to claim 1, wherein an end portion of the second curved line that is continuous with the incident surface is bent toward a central portion of the incident surface.   The optical lens according to any one of claims 1 to 3, wherein the incident surface has a concave portion at a central portion thereof.   5. The optical lens according to claim 4, wherein a cross-sectional shape of the concave portion in a plane orthogonal to the one plane is a curve having a different trajectory from a curve forming a cross-sectional shape of the exit surface in the plane.   The optical lens according to any one of claims 1 to 5, wherein the emission surface is subjected to glare suppression processing in a region of both ends thereof in a plan view orthogonal to the one plane.   An illumination device comprising the optical lens according to any one of claims 1 to 6.