JP2010032232A - Lighting system for indicator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system for an indicator efficiently lighting the indicator with a small number of light sources. <P>SOLUTION: This lighting system for an indicator is equipped with the light sources 3, the indicator 4 emitting light by thereinto introducing light from the light sources through a light receiving part 43, and a ring-shaped light guide 5 guiding the light from the light sources 3 to the indicator 4. The light guide 5 includes a light entering surface 51, a light exiting surface 54, and a reflective surface 53. The exiting surface 54 consists of a condensing surface having a circular arc-shaped cross-section in the radial direction DM in a domain corresponding at least to a rotational track RO of the receiving part 43 and smoothly continuing in the circumferential direction C with the circular arc shape maintained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pointer illumination device applied to, for example, a vehicle meter.

As this kind of pointer illumination device, for example, one described in Patent Document 1 below is known. The pointer illumination device includes a light source composed of a light emitting diode, a pointer composed of a translucent material that emits light upon receiving light from the light source, and a rotation axis of the pointer between the pointer and the light source. And a ring-shaped light guide that guides light from the light source to the pointer.
The ring-shaped light guide has a light incident surface facing the light source and a light exit surface facing the pointer side, and a plurality of light sources are arranged so as to face the light incident surface. A plurality of convex lens surfaces corresponding to each are formed, and light is collected by this convex lens and irradiated onto the pointer.
JP 2001-31633 A

  However, since the illumination device for the pointer described in the above publication has a configuration in which each of the plurality of light sources is arranged in a one-to-one correspondence with each of the plurality of convex lenses, the entire rotation operation range of the pointer is not uneven in brightness. In order to illuminate completely, there is a problem that a large number of light sources are required and an increase in cost cannot be avoided.

  The present invention focuses on the above-described problems and provides a pointer illumination device that can efficiently illuminate the pointer with a small number of light sources.

In order to solve the above-mentioned problems, the present invention provides a light source, a pointer that introduces light from the light source from a light receiving unit, and emits light, and the rotation axis of the pointer between the pointer and the light source. In a pointer illumination device provided with a ring-shaped light guide that is provided as described above and guides light from the light source to the pointer, a light incident surface on which the ring-shaped light guide enters light from the light source, A light exit surface that is formed on a wall surface facing the pointer side and irradiates the pointer with light; and a reflective surface that is formed on a wall surface facing the light exit surface and reflects light incident on the light exit surface toward the light exit surface side. The light exit surface has a radial cross section at least in a region corresponding to the rotational trajectory of the light receiving section, and the light exit surface is a condensing surface smoothly continuing in the circumferential direction while maintaining the arc shape. It is characterized by becoming.
According to this, light can be reflected to the light exit surface through the reflective surface, and the reflected light can be supplied to the pointer through the light exit surface composed of a condensing surface (magnifying lens surface) smoothly smoothly in the circumferential direction. The pointer can be efficiently illuminated with a small number of light sources and with reduced luminance unevenness. In other words, since the light exit surface is formed as a condensing surface that is smoothly continuous in the circumferential direction, the reflective surface can be enlarged when viewed from the pointer side, thereby emitting the light exit surface in a band shape with high brightness. Therefore, the pointer can be efficiently illuminated with a small number of light sources.

  Further, according to the present invention, it is possible to suppress the influence of luminance unevenness exerted by the light source by providing the light source so as to face the light incident surface at a position off the rotational path of the light receiving unit.

  Further, the present invention is such that light entering through the light incident surface is set so as to go in the circumferential direction, and the reflecting surface is set in a sawtooth shape toward the circumferential direction. Illumination efficiency can be increased by increasing the amount of light directed to the surface.

  ADVANTAGE OF THE INVENTION According to this invention, the initial objective can be achieved and the pointer illuminating device which can illuminate a pointer efficiently with few light sources can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 4 show a first embodiment of a pointer illumination device according to the present invention. FIG. 1 is a cross-sectional view showing the overall configuration (hatching other than the ring-shaped light guide is omitted), and FIG. 1 is an exploded perspective view (a part of the ring-shaped light guide is shown in cross section), FIG. 3 is an enlarged perspective view showing the ring-shaped light guide of FIG. 2 alone, and FIG. 4 is a ring-shaped light guide of FIG. It is a perspective view when seeing from the light source side.

  1 and 2, the pointer illumination device according to the present embodiment includes a stepping motor 1, a circuit board 2, a light source 3, a pointer 4, and a ring-shaped light guide 5.

  The stepping motor 1 rotates the pointer shaft 11 in accordance with a measurement amount such as speed and engine speed, and is attached to the back side of the circuit board 2 so that the pointer shaft 11 penetrates the circuit board 2.

  The circuit board 2 is a hard circuit board on which circuit patterns and various circuit elements (not shown) are mounted.

  The light source 3 is composed of, for example, a surface-mount type light emitting diode, and is mounted on the surface of the circuit board 2 so that the pointer 4 is illuminated by one light source 3.

  The pointer 4 includes a cover 41 made of a light-transmitting synthetic resin and made of a light-shielding synthetic resin. The pointer 4 is connected to the pointer shaft 11 of the stepping motor 1 and is provided so as to rotate in accordance with the measured amount. The pointer 4 indicates an indicator portion (not shown) of the scale plate indicated by a one-dot chain line in FIG. A light receiving unit 43 that receives light from the light source 3, and a pointer reflecting surface 44 that reflects light received from the light receiving unit 43 toward the pointing unit 42.

  The ring-shaped light guide 5 is made of a translucent synthetic resin, and is provided between the pointer 4 and the light source 3 so as to surround a rotation axis RA (see FIG. 3) that coincides with the axis of the pointer shaft 11. The light from the light source 3 is guided to the pointer 4 and is fixedly fixed inside a cylindrical light guide reflection wall that surrounds the pointer shaft 11 (not shown).

  As shown in detail in FIGS. 3 and 4, the ring-shaped light guide 5 includes a light incident surface 51 for receiving light from the light source 3 and light incident from the light incident surface by dividing the light into two. A light incident reflection surface 52 that reflects toward the light source, a reflection surface 53 that reflects light from the light incident reflection surface 52 toward the light receiving portion 43 of the pointer 4, and a light receiving portion of the pointer 4 that reflects light from the reflection surface 53. The cross section in the radial direction DM of the region corresponding to the rotation path RO of the light receiving portion 43 of the pointer 4 is substantially “D” having a straight line on the circuit board 2 side. It is a letter shape.

  The light incident surface 51 is formed on the outer wall surface of the protrusion 55 that protrudes in a cylindrical shape from a part of the back surface of the ring-shaped light guide 5 (the surface on the circuit board 2 or the light source 3 side) toward the light source 3. .

  The light incident reflecting surface 52 is a circular shape so that the light that faces the light incident surface 51 can be divided into two and reflected in the circumferential direction using the wall surface facing the pointer 4 side of the ring-shaped light guide 5. A circumferential cross section is formed in a V shape.

  The light incident surface 51, the light incident reflection surface 52, and the protruding portion 55 are formed at positions off the rotational path RO of the light receiving section 43, and the light source 3 is also positioned at a position off the rotational path RO of the light receiving section 43 ( In FIG. 3, it is provided so as to face the light incident surface 51 by a dotted line continuous with the rotation trajectory RO indicated by a solid line). With this configuration, the position of the light source 3 and the position of the light introduction portion are provided. The brightness variation caused by is suppressed.

  The reflecting surface 53 is formed in a sawtooth shape toward the circumferential direction C by using the side wall surface of the circuit board 2 which is a straight portion having a substantially “D” cross section facing the light exit surface 54. These ridge lines and valley lines extend radially around the rotation axis RA. The reflection surface 53 reflects the light reflected in the circumferential direction through the light incident reflection surface 52 to the light exit surface 54 side. Further, the reflection surface 53 is formed only in a region corresponding to the rotation path RO of the light receiving portion 43 of the pointer 4.

  The light exit surface 54 extends in the circumferential direction C so as to cover the rotation path RO of the light receiving unit 43 using a wall surface facing the pointer 4 side. The cross section of the light exit surface 54 in the radial direction DM is an arc shape, and is formed of a condensing surface that smoothly continues without a step in the circumferential direction while maintaining the arc shape. Therefore, when the light exit surface 54 is viewed from the pointer 4 side, it functions as a magnifying lens surface that magnifies the reflective surface 53.

  In the present embodiment configured as described above, the light from the light source 3 enters the ring-shaped light guide 5 from the light incident surface 51, reaches the light incident reflection surface 52 through the protruding portion 55, and this light incident reflection. The surface 52 is reflected in the circumferential direction C. The light reflected in the circumferential direction in this way is further reflected to the light exit surface 54 side through the reflective surface 53, and is emitted from the light exit surface 54 toward the light receiving portion 53, so that the pointer 4 emits light.

As described above, in the present embodiment, the light source 3, the pointer 4 that emits light from the light source 43 through the light receiving unit 43, and the rotation axis RA of the pointer 4 between the pointer 4 and the light source 3. In a pointer illuminating device provided with a ring-shaped light guide 5 provided so as to surround light from the light source 3 to the pointer 4, the ring-shaped light guide 5 receives light from the light source 3. A light exit surface 54 that is formed on the surface 51, a wall surface facing the pointer 51 side, and irradiates the pointer 4 with light; and a light incident on the light exit surface 51 that is formed on the wall surface facing the light exit surface 54. The light exit surface 54 has a circular cross section in the radial direction DM at least in a region corresponding to the rotation orbit RO of the light receiving portion 43, and the circumference of the light exit surface 54 is maintained while maintaining the arc shape. By comprising a condensing surface that continues smoothly in direction C, Light can be reflected through the light emitting surface 53 toward the light emitting surface 54, and the light reflected in this way can be supplied to the pointer 3 through the light emitting surface 54 that is a condensing surface (magnifying lens surface) that smoothly continues in the circumferential direction C. Therefore, it is possible to efficiently illuminate the pointer with a small number of light sources while suppressing luminance unevenness.
That is, since the light exit surface 54 is formed as a condensing surface that smoothly continues in the circumferential direction, the reflective surface 53 can be enlarged when viewed from the pointer 3 side, thereby making the light exit surface 54 highly bright. Therefore, the pointer can be efficiently illuminated with a small number of light sources.

  Further, according to the present embodiment, the light source 3 is provided so as to face the light incident surface 51 at a position off the rotational path RO of the light receiving unit 34, so that the light of the light source 3 directly reaches the pointer 4. This can be prevented, and the influence of uneven brightness due to the light source 3 can be suppressed.

  Further, according to the present embodiment, the light incident through the light incident surface 43 is set so as to go in the circumferential direction C, and the reflecting surface 53 is set in a sawtooth shape toward the circumferential direction C. As a result, the amount of light traveling toward the light exit surface 54 can be increased to increase the illumination efficiency.

  In the present embodiment, the light source 3 is single, but a plurality of light sources 3 may be provided.

  In this embodiment, the reflective surface 53 has a sawtooth shape, but the shape is arbitrary as long as it reflects light toward the circumferential direction C to the light output surface 54 side. It may be.

  FIG. 5 is a plan view showing a ring-shaped light guide according to the second embodiment of the present invention. In this embodiment, the ring-shaped light guide 5 enters light from the light source 3 along the circumferential direction C. FIG. An example of light will be shown.

  That is, in the present embodiment, the light introduction projecting portion 55 extends in a direction perpendicular to the rotation axis RA (parallel to the substrate surface of the circuit board 2), and the light incident surface 51 provided at the end portion is provided on the light source 3. Opposite. The light source 3 is provided so as to be able to irradiate light in a direction orthogonal to the rotation axis RA, whereby the ring-shaped light guide 5 receives light from the light source 3 along the circumferential direction C.

  According to the second embodiment configured as described above, the same effect as that of the first embodiment can be expected.

1 is a cross-sectional view showing an overall configuration of a pointer illumination device according to a first embodiment of the present invention. The exploded perspective view of FIG. The expansion perspective view which shows the ring-shaped light guide of FIG. The perspective view when the ring-shaped light guide of FIG. 3 is seen from the light source side. The front view of the ring-shaped light guide by the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 2 Circuit board 3 Light source 4 Pointer 5 Ring-shaped light guide 11 Pointer shaft 41 Cover 42 Instruction part 43 Light-receiving part 44 Pointer reflecting surface 51 Light incident surface 52 Light incident reflecting surface 53 Reflecting surface 54 Light emitting surface 55 Projection C Circumferential direction DM Radial direction RA Rotating axis RO Rotating orbit

Claims (3)

A light source, a pointer for emitting light by introducing light from the light source from the light receiving unit, and a light guide provided between the pointer and the light source so as to surround a rotation axis of the pointer. In a pointer illumination device comprising a ring-shaped light guide that leads to
The ring-shaped light guide is formed on a light incident surface on which light from the light source is incident, a light exit surface that is formed on a wall surface facing the pointer side, and irradiates the pointer with light, and a wall surface that faces the light exit surface. And a reflecting surface that reflects the light incident through the light incident surface to the light exit surface side,
The light exit surface is a condensing surface that is smoothly continuous in the circumferential direction while maintaining a circular cross section in a radial direction in a region corresponding to the rotation trajectory of the light receiving unit. The indicator lighting device. 2. The pointer illumination device according to claim 1, wherein the light source is provided so as to face the light incident surface at a position off the rotational orbit of the light receiving unit. 2. The light entering through the light incident surface is set so as to go in the circumferential direction, and the reflecting surface is set in a sawtooth shape in the circumferential direction. Pointer lighting system.

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