JP2014175145A - Plane illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simply-configured and down-sized plane illumination device for achieving a uniform luminance distribution.SOLUTION: A plane illumination device includes a light source 1 and a light guide body 2 having the light source 1 at one end in a longitudinal direction X thereof. The light guide body 2 includes: a light guide part 3 for guiding light from the light source 1 from one end to the other end a horizontal diffusion part 6 having a plurality of grooves 5 with a semicircular cross-section extending in the vertical direction Y that is formed along a longitudinal direction X; the horizontal diffusion part 6 diffusing the light from the light source 1 in the horizontal direction H with respect to an irradiation direction; and, on bottoms 5a of the respective grooves 5 arranged in the longitudinal direction X, a vertical diffusion part 8 having a plurality of recessed portions 7 recessed towards a rear direction Z that is formed along the vertical direction Y, the vertical diffusion part 8 diffusing the light from the light source 1 in the vertical direction V with respect to the irradiation direction. The horizontal diffusion part 6 and the vertical diffusion part 8 are disposed on a face opposite the light source 1.

Description

  The present invention relates to a surface illumination device that is used for illumination such as emblem illumination in a vehicular lamp and changes the diffusion direction of light from a light source.

  Conventionally, as this type of vehicular lamp, a technique is known in which the orientation characteristics of a lamp are symmetrical in the case where light is diffused in a horizontal direction with respect to an irradiation direction with a lens tilted. (For example, patent document 1). FIG. 5 shows the configuration of the lens 91 of this vehicular lamp. In the fog lamp, the lens 91 is disposed in an inclined manner along the shape of the vehicle body. In this case, for example, a concave lens cut 92 for diffusing the light applied to the lens 91 in the horizontal direction is larger than the curvature on the side where the curvature of the lens surface becomes an acute angle with respect to the irradiation direction becomes an obtuse angle. It is set small (radius R1> R2).

  It is also known that light is diffused in the horizontal direction with respect to the irradiation direction by alternately arranging convex and concave cylindrical prism lenses (for example, Patent Document 2).

Japanese Utility Model Publication 5-81902 Japanese Utility Model Publication No. 6-6401

  However, in a surface illumination device (emblem illumination), it is difficult to obtain light emission with a uniform luminance distribution only by diffusing light in the horizontal direction with respect to the irradiation direction using the lens as described above. In order to obtain this light emission, there has been a demand for realizing diffusion in the vertical direction with a simple configuration. In this case, since the space of the surface illumination device in the vehicle is narrow and the direction of light through a plurality of lenses and the like cannot be changed, there has been a demand for downsizing the surface illumination device.

  Further, in the prior art, when the light source and the lens surface are separated from each other, it is difficult to bend the irradiation light from the light source in an arbitrary direction, and it is difficult to efficiently emit light as a whole.

  The present invention solves the above problems and guides light from a light source, diffuses light in a horizontal direction with respect to an irradiation direction, and diffuses in a vertical direction with a simple configuration. An object of the present invention is to provide a surface illumination device that can be realized in a small size and can obtain a uniform luminance distribution.

  In order to achieve the above object, a surface illumination device according to one configuration of the present invention includes a light source and a light guide body disposed at one end in a longitudinal direction so as to face the light source, and the light guide body includes: A light guide that guides light from the light source from the one end to the other end and a groove having a semicircular cross section extending in the longitudinal direction perpendicular to the longitudinal direction along the longitudinal direction X on the surface facing the light source And a horizontal diffusion unit that is formed side by side and diffuses light from the light source in the horizontal direction with respect to the irradiation direction.

  According to this configuration, it is easy to guide the light from the light source from one end to the other end by the light guide part of the light guide, and to diffuse the light in the horizontal direction with respect to the irradiation direction by the horizontal diffusion part. It can be realized with a simple structure and a small size, and a uniform luminance distribution can be obtained for the entire light emission.

  In the present invention, the light guide has a vertical diffusion portion in which a plurality of recessed portions recessed rearward are arranged along the longitudinal direction at the bottom of the groove arranged in the longitudinal direction, and the vertical diffusion portion The light from the light source is preferably diffused in the direction perpendicular to the irradiation direction. In this case, it is easy to guide the light from the light source in the direction from one end to the other, diffuse the light in the horizontal and vertical directions with respect to the irradiation direction, and arbitrarily control the diffusion direction in three dimensions. It can be realized with a simple configuration and a small size, and a more uniform luminance distribution can be obtained for the entire light emission.

  Moreover, it is preferable that the said vertical spreading | diffusion part has a scale-like shape in which the said recessed part was formed adjacent to each in the longitudinal direction and the longitudinal direction. In this case, the entire light guide can be diffused in the horizontal and vertical directions with respect to the irradiation direction.

  Preferably, the vertical diffusion portion has a substantially triangular vertical cross-sectional shape having a long side and a short side sandwiching a corner where the concave portion is round, and the long side is rearward with respect to the bus bar at the bottom of the groove. Inclination angle θ is set in the range of θ ≦ 14 °. Therefore, the light can be diffused better in the direction perpendicular to the irradiation direction, and the vertical diffusion part can be easily formed.

  Preferably, the light guide is made of a material containing a scatterer. Therefore, light can be diffused in a direction perpendicular to the irradiation direction, and light emission whose luminance changes gradually can be obtained.

  In the present invention, the light from the light source is guided in the direction from one end to the other end of the light guide, and the light is diffused in the horizontal direction and / or the vertical direction with respect to the irradiation direction. And a uniform luminance distribution can be obtained for the entire light emission.

It is a perspective view which shows the structure of the surface illumination apparatus concerning one Embodiment of this invention. (A), (B) is a top view which shows the diffusion state of the light by a horizontal diffusion part. (A) is a rear view showing a light guide, (B) is a side view showing a vertical diffusion portion, and (C) is a side view showing a light diffusion state by the vertical diffusion portion. (A)-(C) are the characteristic views which show the evaluation result of this invention. It is sectional drawing which shows an example of the conventional surface illumination apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a surface illumination device according to an embodiment of the present invention. The surface illumination device includes a light source (point light source) 1 and a light guide 2 that has a horizontally long plate shape and is disposed so that the light source 1 is opposed to one end in the longitudinal direction X thereof. For example, an LED (light emitting diode) is used as the light source 1, the light guide 2 is made of a transparent material, and acrylic (PMMA) resin, polycarbonate (PC) resin, or the like is used.

  The light guide 2 has a light guide 3 that guides the irradiation light L from the light source 1 from one end to the other in the longitudinal direction X, and a longitudinal direction Y orthogonal to the longitudinal direction X on the surface facing the light source 1. A plurality of grooves 5 having a semicircular cross section extending in the longitudinal direction X are formed side by side, and the diffusion light L2 is diffused in the horizontal direction H with respect to the direction (irradiation direction) of the irradiation light L from the light source 1. And a diffusion unit 6. A convex portion having a semicircular cross section is formed between the grooves 5.

  2A and 2B are plan views showing a light diffusion state by the horizontal diffusion unit. As shown in FIG. 2B, the irradiation light L from the light source 1 is guided by the light guide 3 and travels from one end of the light guide 2 to the other end in the longitudinal direction X (light L1). At the same time, as shown in FIG. 2A, in the horizontal diffusing unit 6, the groove 5 functions as a concave mirror, and the irradiation light L from the light source 1 is reflected by the inner surface of the groove 5 to the irradiation direction. It can be diffused in a wide angle in the horizontal direction H. Similarly, the guided light L1 is diffused at a wide angle in the horizontal direction H. As a result, the entire light guide 2 can be made to emit light efficiently. In addition, when the light guide 2 contains the scatterer 20 described later, it can be diffused in the vertical direction V with respect to the irradiation direction.

  The light guide 2 also includes a vertical diffusion unit 8 that diffuses light from the light source 1 in a direction V perpendicular to the irradiation direction L. 3A is a rear view showing the vertical diffusion unit 8, FIG. 3B is a side view showing the vertical diffusion unit 8, and FIG. 3C is a side view showing a light diffusion state by the vertical diffusion unit 8.

  As shown in FIG. 3B, the vertical diffusion portion 8 is formed with a plurality of recessed portions 7 recessed along the longitudinal direction Y in the bottom 5a of the grooves 5 aligned in the longitudinal direction X. ing. The recessed portion 7 has a substantially (right-angled) triangular vertical cross-sectional shape having a long side 7b and a short side 7c sandwiching a rounded corner 7a, and the long side 7c with respect to the generatrix m of the bottom 5a of the groove 5 Is inclined within the range of θ ≦ 14 °. More preferably, the inclination angle θ is set in a range of 6 ° ≦ θ ≦ 8 °.

  As shown in FIG. 3A, the vertical diffusion portion 8 has a scale-like shape in which a plurality of recessed portions 7 are formed adjacent to each other in the longitudinal direction X and the longitudinal direction Y. As shown in FIG. 3C, the irradiation light L from the light source 1 is reflected in the inner surface of the recessed portion 7 having a rounded corner portion 7a recessed in the rear direction Z in the vertical diffusion portion 8. Diffused light L3 is diffused in the vertical direction V with respect to the irradiation direction (FIG. 1).

  The vertical diffusion part 8 is formed at the bottom 5a of the groove 5 which is a part of the horizontal diffusion part 6, and it is easy to diffuse the irradiation light L in the horizontal direction and the vertical direction with respect to the irradiation direction. In addition to being realized by the configuration, the apparatus can be miniaturized because it is formed integrally with the horizontal diffusion portion 6.

  The vertical diffusion part 8 is produced by the following method, for example. That is, as shown in FIG. 3B, the cylindrical cutting tool C is cut at an angle of θ = 10 ° with respect to the bottom 5a of the groove 5 to form the recessed portion 7, thereby forming the vertical portion By providing a plurality in the direction Y at intervals of about 1 mm, and similarly providing a plurality in the longitudinal direction X, a scale-like shape as shown in FIG. Thereby, it is possible to perform molding at a small angle with respect to the molding punching direction.

  For example, silicone particles are preferably used as the scatterer 20 in FIG. When the light guide 2 is made to contain the scatterer 20 having a predetermined concentration, the light L4 scattered by the scatterer 20 can be diffused in the vertical direction V and light emission whose luminance changes gradually can be obtained.

(Example)
The horizontal diffusion portion 6 has, for example, a knurled shape in which a plurality of grooves 5 having a radius R of 0.1 mm to 1.0 mm are arranged. In the vertical diffusion portion 8, a plurality of recessed portions 7 inclined at an angle of θ = 10 ° with respect to the bottom 5 a of the groove 5 are provided in the vertical direction Y at an interval of about 1 mm.

Example 1: When only the horizontal diffusion part 6 was provided, the simulation result of horizontal diffusion was the best when the convex semi-cylindrical part 4 was R0.2 and the groove 5 was R0.5.
Example 2: When only the horizontal diffusion part 6 was provided, when the convex semi-cylindrical part 4 was R0.3 and the groove 5 was R0.5, the appearance was good.
Example 3 When the horizontal diffusion unit 6 and the vertical diffusion unit 8 are provided, and the horizontal diffusion unit 6 has the same shape as that of the first example, the irradiation light is horizontally and vertically diffused, which is more than in the first example. Luminescence became a more uniform luminance distribution.

  4A to 4C are characteristic diagrams showing the evaluation results of the present invention. 4A shows the case where only the horizontal diffusion unit 6 is provided, FIG. 4B shows the case where the horizontal diffusion unit 6 and the vertical diffusion unit 8 are provided, and FIG. The case where the vertical diffusing portion 8 is provided and the light guide 2 contains the scatterer 20 is shown. 4 (A) to 4 (C), (C) has a uniform luminance distribution regardless of the observation angle and is in the best appearance state, and in the order of (B) and (A), The uniformity due to the observation angle is reduced, and the appearance is slightly reduced.

  Thus, in the present invention, the light from the light source is guided from one end to the other by the light guide of the light guide, and the light is diffused in the horizontal direction with respect to the irradiation direction by the horizontal diffusion unit. It can be realized with a simple configuration and a small size, and a uniform luminance distribution can be obtained for the entire light emission.

  Further, in the present invention, the light from the light source is guided from one end to the other by the light guide of the light guide, and the horizontal and vertical diffusions are used to guide the light in the horizontal and vertical directions with respect to the irradiation direction. The diffusion direction can be arbitrarily controlled in a three-dimensional manner with a simple configuration and reduced in size, and a more uniform luminance distribution can be obtained for the entire light emission.

  In this embodiment, a horizontal diffusion unit that diffuses in the horizontal direction with respect to the irradiation direction and a vertical diffusion unit that diffuses in the vertical direction are provided, but the vertical diffusion unit may be omitted if necessary.

  In this embodiment, the light guide includes a scatterer, but may not be included if necessary.

1: Light source 2: Light guide 3: Light guide 5: Groove 5a: Bottom of groove 6: Horizontal diffuser 7: Recess 7a: Corner 7b: Long side 7c: Short side 8: Vertical diffuser 20: Scatterer L: Irradiation light H: Horizontal direction V: Vertical direction X: Longitudinal direction Y: Longitudinal direction Z: Backward direction in the thickness direction

Claims (5)

A light source, and a light guide body disposed at one end in the longitudinal direction so as to face the light source,
The light guide includes a light guide that guides light from a light source from the one end to the other end, and a groove having a semicircular cross section extending in a longitudinal direction perpendicular to the longitudinal direction on a surface facing the light source. A surface illuminating device comprising: a horizontal diffusing unit that is formed side by side along a longitudinal direction and diffuses light from a light source in a horizontal direction with respect to an irradiation direction. The claim 1, further comprising:
In the light guide, a vertical diffusion portion in which a plurality of recessed portions recessed rearward are arranged along the longitudinal direction is formed at the bottom of the grooves arranged in the longitudinal direction. A surface illumination device that diffuses light in the direction perpendicular to the irradiation direction. In claim 2,
The said vertical diffusion part is a surface illuminating device which has the scale-like shape in which the said recessed part was formed adjacent to each in the longitudinal direction and the longitudinal direction. In claim 2,
The vertical diffusion part has a substantially triangular vertical cross-sectional shape having a long side and a short side sandwiching a rounded corner of the recessed part, and the long side is inclined rearward with respect to the bus bar at the bottom of the groove part. A surface illumination device in which an inclination angle θ is set within a range of θ ≦ 14 °. In any one of Claims 1-4,
The light guide is a surface illumination device made of a material containing a scatterer.

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