JP2004045181A - Pointer illuminating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pointer illuminating structure 1 for improving the luminance of a pointer 10 and keeping the luminance uniform in an entire rotation area of the pointer 10 using one lighting source. <P>SOLUTION: The pointer luminance structure is equipped with the transparent pointer 10, one light emitting diode 30 for illuminating the pointer 10, and a light guide body 20 provided between the pointer 10 and the light emitting diode 30. The light guide body 20 has a light emitting surface 22 emitting light from the light emitting diode 30 to the pointer 10 and a plurality of reflective surfaces reflecting light entered into the light guide body 20. The light emitting surface 22 emits light by light passing through the light emitting body 20 directly to the light emitting surface 22, by light reflected on one reflective surface 24 and passed to the light emitting surface 22, and by light sequentially reflected on three reflective surfaces 25, 26 and 27 and passed to the light emitting surface 22. Thus, one light emitting diode 30 can improve the luminance of the pointer 10 and keep the luminance uniform in the entire rotation area of the pointer 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pointer lighting structure used for an instrument device using a pointer such as a vehicle.
[0002]
[Prior art]
For a pointer illumination structure used in an instrument device that uses a pointer such as a vehicle, it is necessary to obtain sufficient luminance of the pointer over the entire pointer indication range, that is, the entire rotation range of the pointer. It is required to prevent uneven brightness. In order to satisfy such demands, various ideas have been devised in the conventional pointer lighting structure. As a conventional pointer illumination structure, for example, there is one shown in Japanese Patent Application Laid-Open No. 2001-215138. This includes a pointer provided with an indicator for transmitting light, a plurality of pointer illumination light sources provided for illuminating the pointer, and a light guide provided between the pointer and the pointer illumination light source. A plurality of light receiving portions for condensing light from the pointer illumination light source are provided for each pointer illumination light source on the pointer illumination light source side of the light guide. This makes it possible to increase the brightness of the hands and at the same time prevent unevenness in brightness of the hands due to the rotation of the hands, that is, to keep the brightness of the hands constant regardless of the rotation angle of the hands.
[0003]
[Problems to be solved by the invention]
However, in the pointer illumination structure disclosed in Japanese Patent Application Laid-Open No. 2001-215138, a plurality of light sources are used, and four light sources are used in the embodiment. For this reason, problems such as an increase in cost and an increase in temperature of the drive circuit due to an increase in current consumption of the light source occur.
[0004]
As a countermeasure for this, for example, it is conceivable to reduce the number of light sources and to mix a light diffuse reflection material into the light guide. Thus, it is possible to make the luminance of the light emitting surface of the light guide uniform with a small number of light sources, and to prevent unevenness in the brightness of the hands accompanying rotation of the hands. However, in this case, the light use efficiency of the light source decreases due to the light diffuse reflection material. Therefore, it is necessary to use a light source with higher luminance, that is, a higher price, so that a sufficient luminance of the pointer can be obtained, and there is a problem that the cost also increases.
[0005]
The present invention has been made in view of the above points, and an object of the present invention is to provide a pointer illumination structure capable of increasing the luminance of a pointer over the entire rotation range of the pointer and maintaining the luminance of the pointer uniformly with one light source. I do.
[0006]
[Means for Solving the Problems]
The present invention employs the following technical means to achieve the above object.
[0007]
The pointer illumination structure according to claim 1 of the present invention includes a pointer made of a translucent material, one light source for illuminating the pointer, and a light guide provided between the pointer and the light source. The light guide includes a light emitting surface for emitting light from the light source toward the pointer and a plurality of reflecting surfaces for reflecting light incident from the light source into the light guide, and the light emitting surface emits light directly in the light guide. Light is emitted by light traveling toward the surface, light traveling toward the light-emitting surface after being reflected by one reflection surface, and light traveling toward the light-emitting surface by being continuously reflected by the three reflection surfaces. As a result, the entire circumference of the light emitting surface can be illuminated with high brightness and uniform brightness by using one light source, so that the brightness of the hands is increased and the brightness of the hands is maintained uniform over the entire rotation range of the hands. it can. Here, the angle of incidence of light from the light source on each reflection surface of the light guide is the total reflection angle of the light guide material, that is, the angle at which the entire amount of light incident on the reflection surface is reflected (in the case of acrylic resin). , About 45 degrees), or by setting the shape of the light guide so as to have an angle close to the angle, the loss of light from the light source incident on the light guide is substantially zero, that is, the light source incident on the light guide Almost 100% of the light from is available for illumination of the hands. In addition, since the number of reflections inside the light guide is suppressed to a maximum of three times, the difference in light emission luminance of each part corresponding to light passing through the above three types of paths on the light emitting surface can be extremely small. The unevenness of the luminance on the light emitting surface of the body can be almost eliminated.
[0008]
According to the second aspect of the invention, the light guide has a convex surface facing the light source. Accordingly, a part of the light incident on the light guide from the light source can be refracted by the convex surface and travel as parallel rays toward the light guide directly in the light guide, thereby increasing the brightness of the light emitting surface.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example in which a pointer lighting structure according to an embodiment of the present invention is applied to a pointer lighting structure 1 in a combination meter mounted on an automobile will be described with reference to the drawings.
[0010]
The combination meter 100 is provided in front of the driver's seat in the cabin of the vehicle, and displays the operating state (running speed, engine speed, etc.) of the vehicle so that the driver can visually recognize the operating state by turning the pointer 10. .
[0011]
Hereinafter, the structure of the combination meter 100 will be briefly described. FIG. 1 is a cross-sectional view of a combination meter 100 including a pointer lighting structure 1 according to an embodiment of the present invention.
[0012]
The combination meter 100 rotates the hands 10 along the surface of the dial 50 and indicates a predetermined physical quantity by the angle of the hands 10.
[0013]
The graduation plate 50 is formed of a thin plate such as a resin or metal, and has graduations and numerals (not shown) on its surface (the right surface in FIG. 1).
[0014]
On the back side of the dial 50 (the left side in FIG. 1), a printed circuit board 60 that forms an electric circuit portion of the combination meter 100 is arranged.
[0015]
One light emitting diode 30 as one light source for illuminating the pointer 10 is mounted on the printed circuit board 60. The movement 40 for rotating the hands 10 is attached to the printed board 60.
[0016]
The movement 40 includes, for example, a cross-coil type driving unit (not shown), and rotates the shaft 41 by an angle corresponding to an external electric signal. The shaft 41 extends from the center hole 51 of the dial 50 toward the surface of the dial 50, and the pointer 10 is fixed to the tip thereof.
[0017]
The pointer 10 is formed of a translucent material such as a transparent acrylic resin or a polycarbonate resin. The light guide 20 is arranged between the pointer 10 and the light emitting diode 30. A through hole 21 is provided in the light guide 20, and a shaft 41 is inserted substantially coaxially into the through hole 21. The end face of the through hole 21 on the pointer 10 side is an annular light emitting surface 22. The light guide 20 is mounted on the printed circuit board 60 so as to cover the light emitting diode 30, and the light emitted from the light emitting diode 30 causes the light emitting surface 22 to emit light in a ring shape, and the light illuminates the pointer 10. I have. That is, by causing the light emitting surface 22 to emit light in a ring shape, the hands 10 are displayed with a constant brightness regardless of the rotation angle. The pointer 10 is provided with a light-shielding cap 11 made of resin or metal. The light-shielding cap 11 prevents light emitted from the light-emitting surface 22 of the light guide 20 from directly going to the driver's eyes and dazzling the driver.
[0018]
The above-mentioned scale 50, printed circuit board 60, movement 40 and the like are accommodated and fixed in a resin case 70. Further, a transparent cover 80 is attached to the case 70.
[0019]
In the combination meter 100 described above, the pointer 10, the light guide 20, and the light emitting diode 30 constitute the pointer illumination structure 1.
[0020]
By the way, in the pointer lighting structure 1 according to one embodiment of the present invention, as shown in FIG. 1, the light emitting surface 22 of the light guide 20 is formed annularly around the through hole 21. On the other hand, as a light source for emitting light from the light emitting surface 22, one light emitting diode 30 is arranged offset to the outer peripheral side of the through hole 21. Therefore, merely guiding the light from the light emitting diode 30 to the light emitting surface 22 only causes a part of the light emitting surface 22, that is, a portion corresponding directly above the light emitting diode 30 to emit light. It cannot emit light in a ring. Therefore, in the pointer illumination structure 1 according to the embodiment of the present invention, the shape of the light guide 20 is devised, that is, a plurality of reflection surfaces 24 to 27 are provided, and light from the light emitting diode 30 is transmitted to each of the reflection surfaces 24 to 27. The light is reflected at 27 and guided to the light emitting surface 22, so that the light emitting surface 22 emits light in a ring shape.
[0021]
Next, the pointer illumination structure 1 according to one embodiment of the present invention will be described focusing on the shape of the light guide 20 and its light guiding action, which are features of the structure.
[0022]
First, the configuration of the light guide 20 will be described in detail.
[0023]
FIG. 2 shows a perspective external view of the light guide 20 in the pointer lighting structure 1 according to one embodiment of the present invention. FIG. 3 is a top view of the light guide 20, and is a view as seen in the direction of the arrow III in FIG. FIG. 4 is a bottom view of the light guide 20 and is a view taken in the direction of the arrow IV in FIG. 5 to 9 are cross-sectional views of the light guide 20, and FIGS. 5, 6, 7, and 9 are cross-sectional indication lines VV, IV-IV, and IIV-IIV in FIG. , IX-IX. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. In FIGS. 5, 6, 7, and 9, the printed circuit board 40 and the light emitting diode 30 are also illustrated.
[0024]
The light guide 20 is formed of a transparent resin, for example, an acrylic resin or a polycarbonate resin.
[0025]
The light guide 20 is provided with a through hole 21. In the combination meter 100, as shown in FIG. 1, the shaft 41 of the movement 40 extends through the through hole 41 toward the front side of the dial 50. . Here, the shaft 41 is disposed substantially coaxially with the through hole 41.
[0026]
The light guide 20 includes a light emitting surface 22 facing the pointer 10. The light emitting surface 22 is formed in a ring shape around the through hole 21 as shown in FIGS. 2 and 3. Therefore, when the light emitting diode 30 is turned on, the light emitting surface 2 emits light in a ring shape to illuminate the pointer 10. Thus, the pointer 10 always emits light with a constant brightness regardless of the rotation angle.
[0027]
On the lower surface side of the light guide 20, a convex surface 23 facing the light emitting diode 30 is formed. The convex surface 23 is formed so as to project toward the light emitting diode 30 as shown in FIG. As shown in FIG. 5, the light guide 20 is mounted on the printed circuit board 60 so that the central axis of the convex surface 23 and the optical axis of the light emitting diode 30 substantially match.
[0028]
In addition, the light guide 20 has a plurality of reflection surfaces 24, 25, 26, and 27 that reflect light that has entered the light guide 20 from the light emitting diode 30, as shown in FIGS. Is formed. The reflecting surface 24 is a single surface that is symmetrical and continuous with respect to the line VV in FIG. 3, and the reflecting surfaces 25, 26, and 27 are a pair of surfaces that have the line VV in FIG. , That is, two each are provided.
[0029]
Next, the light guiding action of the light guide 20 will be described.
[0030]
The light emitting diode 30 emits light in all directions upward in FIG. 5, but most of the light amount is concentrated within a conical area having a predetermined central angle. The role of the light guide 20 in the pointer lighting structure 1 according to one embodiment of the present invention is to guide light emitted from the light emitting diode 30, mainly light within the above-described predetermined central angle conical range, to the light emitting surface 22 with high efficiency. That is, light is emitted from the light source toward the pointer 10 as a light beam parallel to the shaft 41. Therefore, in the pointer lighting structure 1 according to the embodiment of the present invention, the light from the light emitting diode 30 is guided to the light emitting surface 22 in the light guide 20 through three paths. Hereinafter, each of these paths will be described.
[0031]
(1) Light traveling directly toward the light emitting surface 22 in the light guide 20.
[0032]
In this case, as shown by an arrow in FIG. 5, the light emitted from the light emitting diode 30 enters the light guide body 20 from the convex surface 23, is refracted by the convex lens function of the convex surface 23, and is refracted in the axial direction of the through hole 21. That is, the light travels toward the light emitting surface 22 in parallel with the axial direction of the shaft 41. This light causes the light emitting section 22a to emit light on the light emitting surface 22, as shown in FIG. In addition, by providing the convex surface 23, light from the light emitting diode 30 can be condensed toward the light emitting surface 22, so that the luminance of the light emitting unit 22a can be increased.
[0033]
(2) Light reflected by one reflection surface 24 toward the light emitting surface.
[0034]
In this case, as shown by an arrow in FIG. 6, light emitted from the light emitting diode 30 and entering the light guide 20 is reflected by the reflection surface 24 and is parallel to the axial direction of the shaft 41 (the light emission surface 22). To the light emitting surface 22). This light causes the light emitting portion 22b to emit light on the light emitting surface 22, as shown in FIG.
[0035]
Here, since the reflecting surface 24 is set to have a shape acting as a concave mirror having the light emitting diode 30 as a focal point, almost all of the light from the light emitting diode 30 incident on the reflecting surface 24 is emitted from the light emitting unit 22b. Can be.
[0036]
(3) Light continuously reflected by the three reflecting surfaces 25, 26, and 27 and traveling toward the light emitting surface.
[0037]
In this case, the light emitted from the light emitting diode 30 first enters the light guide body 20 from the convex surface 23 as shown by an arrow in FIG. 7, and is refracted by the convex lens function of the convex surface 23 to become substantially parallel light. As a result, the light is incident on the reflection surface 25, is reflected on the reflection surface 25 toward the reflection surface 26, and is incident on the reflection surface 26 as substantially parallel light rays. Next, the light incident on the reflection surface 26 is reflected by the reflection surface 26 and is incident on the reflection surface 27 as indicated by an arrow in FIG. Subsequently, the light incident on the reflecting surface 27 is reflected by the reflecting surface 27 and is parallel to the axial direction of the shaft 41 (the direction of incidence on the light emitting surface 22 at an incident angle of 0) as indicated by an arrow in FIG. It proceeds toward the light emitting surface 22. This light causes the light emitting portion 22c to emit light on the light emitting surface 22, as shown in FIG.
[0038]
Here, each of the reflection surfaces 25, 26, and 27 is such that the angle of incidence of light from the light emitting diode 30 on each of the reflection surfaces 25, 26, and 27 is the total reflection angle of the material of the light guide 20, ie, each of the reflection surfaces 25, The positional relationship is set so that the angle is such that the entire amount of light incident on 26 and 27 is reflected (about 45 degrees in the case of acrylic resin), or an angle close thereto. Therefore, the light that has entered the reflecting surface 25 from the light emitting diode 30 is emitted from the light emitting surface 22 with the loss in the optical path being almost zero.
[0039]
As described above, the light incident on the light guide 20 from one light emitting diode 30 is guided to the light emitting surface 22 through the three paths described above, and the light emitting portions 22a, 22b, and 22c of the light emitting surface 22 are respectively formed. By emitting light, the light emitting surface 22 can emit light in a ring shape.
[0040]
In the pointer illumination structure 1 according to the embodiment of the present invention described above, the pointer 10 made of a translucent material, one light emitting diode 30 for illuminating the pointer 10, the pointer 10 and the light emitting diode 30 And a light guide 20 provided between the light guides 20, and the light guide 20 is incident on the light guide 20 from the light emitting surface 22 and the light emitting diode 30 for emitting light from the light emitting diode 30 toward the pointer 10. The light emitting surface 22 includes a plurality of reflecting surfaces 24 to 27 that reflect light, and the light emitting surface 22 directs light inside the light guide 20 to the light emitting surface 22 and light reflected by one reflecting surface 24 toward the light emitting surface 22. Each of the light-emitting portions 22a, 22b, and 22c emits light by the light and the light sequentially reflected by the three reflection surfaces 25, 26, and 27 and traveling toward the light-emitting surface 22. As a result, the entire circumference of the light emitting surface 22 can be illuminated with high luminance and uniform brightness by using one light emitting diode 30, so that the luminance of the pointer 10 can be increased over the entire rotation range of the pointer 10 and the pointer 10 can be increased. Brightness can be maintained uniform.
[0041]
In the pointer lighting structure 1 according to the embodiment of the present invention described above, the light emitting diode 30 is used as a light source, but another light source, for example, a light bulb or the like may be used.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a combination meter 100 using a pointer lighting structure 1 according to an embodiment of the present invention.
FIG. 2 is a perspective external view of a light guide 20 of the pointer lighting structure 1 according to one embodiment of the present invention.
FIG. 3 is a top view of the light guide 20, and is a view as viewed in the direction of the arrow III in FIG.
FIG. 4 is a bottom view of the light guide 20, and is a view taken in the direction of the arrow IV in FIG.
FIG. 5 is a sectional view taken along line VV in FIG. 3;
FIG. 6 is a sectional view taken along line VI-VI in FIG. 3;
FIG. 7 is a sectional view taken along line VII-VII in FIG.
8 is a sectional view taken along line VIII-VIII in FIG.
FIG. 9 is a sectional view taken along line IX-IX in FIG. 3;
[Explanation of symbols]
1 pointer illumination structure 10 pointer (pointer illumination structure)
20 Light guide (pointer lighting structure)
21 Through-hole 22 Light-emitting surface 22a, 22b, 22c Light-emitting part 23 Convex surface 24 Reflection surface 25 Reflection surface 26 Reflection surface 27 Reflection surface 30 Light-emitting diode (light source, pointer illumination structure)
Reference Signs List 40 Rotating inner machine 41 Pointer shaft 50 Dial 60 Printed circuit board 70 Case 80 Transparent cover 100 Combination meter

Claims (2)

A guide made of a translucent material;
One light source for illuminating the pointer,
Comprising a light guide provided between the pointer and the light source,
The light guide includes a light emitting surface that emits light from the light source toward the pointer and a plurality of reflection surfaces that reflect light that has entered the light guide from the light source,
The light-emitting surface reflects the light directly toward the light-emitting surface and the light reflected by one of the reflective surfaces in the light guide, and continuously reflects the light toward the light-emitting surface and the three reflective surfaces. A pointer lighting structure characterized in that light is emitted by light traveling toward. The pointer lighting structure according to claim 1, wherein the light guide includes a convex surface facing the light source.

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