JP2007199390A - Cylindrical light guiding member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical light guiding member which is easy to manufacture and in which point lighting is prevented in a center section of a light emitting surface. <P>SOLUTION: The cylindrical light guiding members 18L and 18R which are located between translucent direction indicate display sections 11L and 11R provided in a compartment side of a combination meter device 1 of a vehicle, and LEDs 7L and 7R for respectively transmitting and illuminating the direction indicate display sections 11L and 11R from a rear side, guide light which is emitted from each of the LEDs 7L and 7R to each of the direction indicate display sections 11L and 11R. In the LEDs 7L and 7R side of each cylindrical light guide members 18L and 18R, cylindrical sections 12L and 12R with a circular inner face, in which a long direction cross section shape of an inner face is a circle, and in the direction indicate display sections 11L and 11R side, cylindrical sections 14L and 14R with a rectangular inner face, in which a long direction cross section shape of the inner face is a rectangle, are provided in the cylindrical light guide members 18L and 18R. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light guide member used in a vehicle combination meter device.

  Conventionally, a cylindrical light guide member shown in FIGS. 1 and 2 is known. FIG. 1 is an exploded perspective view of a vehicle combination meter device.

  1 is a combination meter device, 2 is a wiring board, 3 is a lower housing, 4 is a dial, 5 is an upper housing, and 6 is a translucent cover.

  LEDs 7 </ b> L and 7 </ b> R are mounted on the front surface of the passenger compartment on the wiring board 2, and the wiring board 2 is mounted on the back side of the lower housing 3.

  The lower housing 3 is formed of white resin, and cylindrical tubular light guide members 8L and 8R are integrally formed vertically from the housing wall 3a of the lower housing 3 toward the passenger compartment side.

  A dial 4 printed with characters, pictograms, and the like is attached to the lower housing 3 on the passenger compartment side, and the upper portion of the dial 4 is cut to avoid contact with the cylindrical light guide members 8L and 8R. Notches 9L and 9R are provided.

  The upper housing 5 is attached to the lower housing 3 from the vehicle compartment side via the dial 4. The upper housing 5 covers the casing 4 side of the dial 4 for makeup.

  The upper housing 5 is provided with holes 10L and 10R through which the cylindrical light guide members 8L and 8R pass, and a translucent cover 6 is mounted on the upper housing 5 on the vehicle compartment side.

  The semi-transparent cover 6 is provided with direction indication display portions 11L and 11R, and the direction indication display portions 11L and 11R are respectively printed with left and right arrows for direction indication.

  FIG. 2A is a perspective view mainly showing the cylindrical light guide member 8R, and FIG. 2B is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 2A, the cylindrical light guide member 8R includes an inner circular cylinder portion 12R and an inner circular cylinder portion 13R.

  The light emitted from the LED 7R is reflected by the inner wall surface 13Ra of the inner circular cylinder portion 13R, guided to the illumination surface 11Ra on the back surface side of the direction indication display portion 11R, and illuminates the direction indication display portion 11R from the back surface side.

  Although illustration of the cylindrical light guide member 8L is omitted, the light emitted from the LED 7L is similarly guided to illuminate the direction indication display portion 11L from the back side.

  In the cylindrical light guide members 8L and 8R configured as described above, when one of the LEDs 7L and 7R emits light, one of the corresponding direction indication display units 11L and 11R is lit by the emitted light. Thus, the driver can be informed of the steering direction.

  In addition, about the code | symbol of each part of the left cylindrical light guide member 8L etc. which abbreviate | omitted illustration, R shall be attached | subjected instead of L in the code | symbol of each part of the corresponding right cylindrical light guide member 8R.

In addition, a navigation instrument of Patent Document 1 that transmits and illuminates a rectangular liquid crystal panel with a circular light guide is known.
JP-A-4-143193

  However, as will be described later, in the conventional tubular light guide member 8R, the intensity of light applied to the central point P of the illumination surface 11Ra is higher than that around the central point P. There has been a problem that the central portion of the viewed direction indication display portion 11R is lit brightly and shines in comparison with the surroundings. The same applies to the direction instruction display portion 11L.

  For this reason, in the cylindrical light guide members 8L and 8R of the conventional example, the direction indication display portions 11L and 11R may be deteriorated in appearance.

  Here, taking the case where the LED 7R is lit as an example, the cause of this flashing will be described with reference to FIG.

  As shown in FIG. 2, a light emitting point O of the LED 7R is used as an origin, a z axis that coincides with the optical axis of light emitted from the LED 7R (symmetrical axis of directivity) and travels in the light traveling direction, The x axis and the y axis are orthogonal to each other on a plane that passes through O and is perpendicular to the z axis.

  When the driver looks at the combination meter device 1 from the passenger compartment side, the x-axis is set to the right in the horizontal direction, and the y-axis is set upward to the combination meter device 1.

  A three-dimensional polar coordinate system (r, θ, φ) corresponding to such a three-dimensional orthogonal coordinate system (x, y, z) is defined. That is, the length of the radius from the origin to an arbitrary point (x, y, z) is r, the polar angle formed by the radius with the z axis is θ, and the orthogonal projection of the radius to the xy plane is the x axis. Let azimuth be φ.

  By the way, the light emitted from the LED 7R is radiated into a cone that spreads with the light emitting point O of the LED 7R as the apex and the z axis as the axis of symmetry.

  In particular, light rays spreading in a conical surface having a certain polar angle θ have substantially the same intensity at the same radius r and an arbitrary azimuth angle φ. That is, the directivity of light emitted from the LED 7R has rotational symmetry with the optical axis as the symmetry axis.

Here, for example, a light beam emitted from the light emitting point O, reflected by the point M1 on the inner wall surface 13Ra and traveling to the center point P of the illumination surface 11Ra is defined as a light beam B1, and the polar angle θ in the radiation direction of the light beam B1. Is θ ₀ .

  Further, it is assumed that the reflection point M1 is on a circle C that is an intersection line between a plane including the point M on the z axis and perpendicular to the z axis, and the cylindrical inner wall surface 13Ra.

By the way, the light ray B2 radiated in the direction of the azimuth angle φ different from the light ray B1 at the same polar angle θ ₀ is reflected at a point M2 different from the point M1 on the circle C, and the central point P of the illumination surface 11Ra. To reach.

This is because the inner wall surface 13Ra is cylindrical and has rotational symmetry with respect to the optical axis (z-axis), and the polar angle θ in the radiation direction of the light beam B1 and the polar angle θ in the radiation direction of the light beam B2 are. Since they are the same θ ₀ , the incident angle of the light beam B1 to the inner wall surface 13Ra and the incident angle of the light beam B2 to the inner wall surface 13Ra are equal.

Therefore, the reflection angle of the light beam B1 from the inner wall surface 13Ra and the reflection angle of the light beam B2 from the inner wall surface 13Ra are also equal, and further, the distance a ₁ from the point M to the point M1 and the distance from the point M to the point M2. a ₂ and because of equal distance from the intersection of the beam B1 and the optical axis to the point M, and, since coincides with the distance from the intersection of the beam B2 and the optical axis and the point M, light B2 also illumination surface 11Ra Converge to the central point P.

Moreover, due to the rotational symmetry of the inner wall surface 13Ra with respect to the optical axis (z-axis), all the light rays emitted in the different azimuth angle φ directions at the same polar angle θ ₀ all pass from the light emitting point O to the central point P of the illumination surface 11Ra. Since the optical path lengths up to and including these central points P are all in phase, they interfere and strengthen each other.

  In order to suppress the focusing of the illumination by the LEDs 7L and 7R to the central portion, there is a method of diffusing light by providing fine irregularities on the inner peripheral surface of the inner circular cylindrical portions 13L and 13R. There is a problem that it is difficult to manufacture by press molding.

  Therefore, an object of the present invention is to provide a cylindrical light guide member that is easy to manufacture and in which the central portion of the illumination surface does not light up.

In order to achieve the above-mentioned object, the invention described in claim 1 is provided between a translucent display unit provided on a vehicle compartment side of a vehicle meter device and a light source that transmits and illuminates the display unit from the back side. A cylindrical light guide member that guides light emitted from the light source to the display unit,
An inner circular tube portion whose inner circumferential surface has a circular cross section on the light source side, and an inner square tube portion whose inner circumferential surface has a square shape on the display portion side, and It features a cylindrical light guide member having

  According to the first aspect of the present invention configured as described above, the light beam is distributed around the central portion of the display unit by making the longitudinal cross-sectional shape of the inner peripheral surface of the inner rectangular tube part a rectangular shape. Thus, it is possible to prevent the light beam from being focused on the central portion of the display portion, and to prevent the central portion of the display portion from being lit up.

  For this reason, when the display unit is viewed from the passenger compartment side of the vehicle, the display unit does not light up and looks good.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a best mode for carrying out a cylindrical light guide member of the invention will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected about the part thru | or equivalent to a prior art example.

<Constitution>
FIG. 3 is an exploded perspective view of the vehicle combination meter device.

  1 is a combination meter device, 2 is a wiring board, 3 is a lower housing, 4 is a dial, 5 is an upper housing, and 6 is a translucent cover.

  On the wiring board 2, LEDs 7L and 7R are mounted on the surface on the passenger compartment side, and there are a movement (not shown) for driving the pointer of the meter, a plurality of LEDs for transmitting illumination (not shown) in addition to the LEDs 7L and 7R, and the like. Has been implemented.

  The wiring board 2 is mounted on the back side of the lower housing 3. The lower housing 3 is formed of a white resin, and a plurality of light guide holes are provided to guide the illumination of the LEDs other than the LEDs 7L and 7R to the dial 4.

  In the lower housing 3, cylindrical light guide members 18L and 18R are integrally formed vertically from the housing wall 3a toward the passenger compartment.

  A dial 4 on which characters, pictograms, and the like are printed is attached to the passenger compartment side of the lower housing 3, and these characters, pictograms, and the like are transmitted and illuminated from the back side by LEDs other than the LEDs 7L and 7R.

  The dial 4 is provided with a hole through which a movement shaft (not shown) is inserted, and notches 9L and 9R are provided at the top of the dial 4 to avoid contact with the cylindrical light guide members 18L and 18R. Is provided.

  The upper housing 5 is attached to the lower housing 3 from the passenger compartment side via the dial 4 and covers the passenger compartment side of the dial 4 for makeup. Further, a pointer (not shown) is attached to the shaft of the inserted movement.

  The upper housing 5 is provided with a display window for displaying a speedometer, a tachometer, a fuel fuel gauge, and the like. At the upper part of the upper housing 5, holes 10L and 10R through which the cylindrical light guide members 18L and 18R penetrate are provided. Is provided.

A translucent cover 6 is attached to the upper housing 5 on the vehicle compartment side. The semi-transparent cover 6 is provided with direction indication display portions 11L and 11R, and arrows directed to the left and right for direction indication are printed on the direction indication display portions 11L and 11R, respectively.
<Configuration of cylindrical light guide member 18R>
4A is a perspective view mainly illustrating the cylindrical light guide member 18R, and FIG. 4B is a cross-sectional view taken along the line BB in FIG. 4A.

  As shown in FIG. 4A, the cylindrical light guide member 18R is interposed between the LED 7R and the direction indication display portion 11R, and is integrally formed perpendicularly to the housing wall 3a.

  The cylindrical light guide member 18 </ b> R is formed of a white resin that reflects the light well with the same color as the lower housing 3.

  The cylindrical light guide member 18R has an inner circular tube portion 12R whose inner circumferential surface has a circular shape on the LED 7R side and a square shape whose inner circumferential surface has a square shape on the illumination surface 11Ra side. It is comprised by 14R of inner side square cylinder parts which exhibited. Moreover, the longitudinal cross-sectional shape of the outer peripheral surface of the cylindrical light guide member 18R has a circular shape.

  The inner wall surface 12Ra of the inner circular tube portion 12R has a cylindrical side surface shape, and a columnar cylindrical space 12Rb surrounded by the inner wall surface 12Ra is formed inside the inner circular tube portion 12R. Further, the length of the inner circular cylindrical portion 12R is formed to be less than 1/5 of the length of the cylindrical light guide member 18R.

  As shown in FIG. 4B, the inner wall surface 15R of the inner rectangular tube portion 14R is composed of planar inner wall surfaces 15Ra, 15Rb, 15Rc, and 15Rd. A quadrangular prism space 16 surrounded by inner wall surfaces 15Ra, 15Rb, 15Rc and 15Rd is formed.

  When the driver looks at the combination meter device 1 from the passenger compartment side, the intersection line 17Ra between the inner wall surface 15Rd and the inner wall surface 15Ra is on the right side in the horizontal direction, and the intersection line 17Rc between the inner wall surface 15Rb and the inner wall surface 15Rc is in the horizontal direction. On the left side, an intersection line 17Rb between the inner wall surface 15Ra and the inner wall surface 15Rb is located on the upper side, and an intersection line 17Rd between the inner wall surface 15Rc and the inner wall surface 15Rd is located on the lower side.

  The configuration of the cylindrical light guide member 18R has been described above. Since the left and right cylindrical light guide members 8L and 8R are symmetrical to each other, the cylindrical light guide member 18L will be described in the same manner.

In addition, about the code | symbol of each part of the left cylindrical light guide member 18L etc. which abbreviate | omitted illustration, R shall be attached | subjected instead of L in the code | symbol of each part of the corresponding right cylindrical light guide member 18R.
<Operational effect by the cylindrical light guide member 18R>
When the LED 7R is turned on, the light emitted from the LED 7R is guided to the illumination surface 11Ra on the back surface side of the direction indication display portion 11R via the cylindrical space 12Rb and the rectangular column space 16.

  At this time, some light is transmitted directly to the illumination surface 11Ra, and some light is reflected and transmitted to the inner wall surface 12Ra and the inner wall surface 15R.

  Although illustration of the cylindrical light guide member 18L is omitted, the light emitted from the LED 7L is similarly guided to illuminate the direction indication display portion 11L from the back side.

  In the cylindrical light guide members 18L and 18R configured as described above, when one of the LEDs 7L and 7R emits light, one of the corresponding direction indication display units 11L and 11R is lit by the emitted light. Thus, the driver can be informed of the steering direction.

The operational effects of the cylindrical light guide member 18R have been described above, but the cylindrical light guide member 18L is also described in the same manner.
<Coordinate axis setting>
As shown in FIG. 4, the light emitting point O of the LED 7R is used as an origin, the z-axis that coincides with the optical axis of light emitted from the LED 7R (the symmetry axis of directivity) and travels in the light traveling direction, The x axis and the y axis are orthogonal to each other on a plane that passes through O and is perpendicular to the z axis.

  When the driver looks at the combination meter device 1 from the passenger compartment side, the x-axis is set to the right in the horizontal direction, and the y-axis is set upward to the combination meter device 1.

  That is, the extension line of the intersection line 17Ra intersects the positive x-axis perpendicularly, the extension line of the intersection line 17Rc intersects the negative x-axis perpendicularly, the extension line of the intersection line 17Rb intersects the positive y-axis perpendicularly, The coordinate axis is taken so that the extended line of the intersection line 17Rd intersects the negative y axis perpendicularly.

A three-dimensional polar coordinate system (r, θ, φ) corresponding to such a three-dimensional orthogonal coordinate system (x, y, z) is defined. That is, the length of the radius from the origin to an arbitrary point (x, y, z) is r, the polar angle formed by the radius with the z axis is θ, and the orthogonal projection of the radius to the xy plane is the x axis. Let azimuth be φ.
<Direction of light>
By the way, the light emitted from the LED 7R is radiated into a cone that spreads with the light emitting point O of the LED 7R as the apex and the z axis as the axis of symmetry.

In particular, light rays spreading in a conical surface having a certain polar angle θ have substantially the same intensity at the same radius r and an arbitrary azimuth angle φ. That is, the directivity of light emitted from the LED 7R has rotational symmetry with the optical axis as the symmetry axis. Well, the LED 7L has the same directivity.
<Attenuation of light intensity due to light reflection>
Although the cylindrical light guide member 18R of the present embodiment is made of a white resin that reflects light well, the reflectance is usually about 70% to 90%.

For example, when the reflectance of the white resin used for the cylindrical light guide member 18R is 70%, when the light is reflected by the inner wall surface 12Ra and the inner wall surface 15R, the amount of reflected light with respect to the amount of incident light. Is attenuated to 70% by one reflection, 49% by two reflections, and 34.3% by three reflections. (Here, the amount of light is the energy of light passing through a unit area per unit time.)
Therefore, when illuminating the illumination surface 11Ra, the light whose number of reflections on the inner wall surface 12Ra and the inner wall surface 15R is three times or more is neglected because the amount of light is weaker than the light reflected once or twice. can do. Note that light attenuation also occurs in the cylindrical light guide member 18L.
<About the length of the inner circular cylindrical portion 12R>
FIG. 5 is a cross-sectional view taken along the line CC of the cylindrical light guide member 18 </ b> R shown in FIG. In FIG. 5, the number of reflections of the light emitted from the LED 7R increases with the inner wall surface 12Ra and the inner wall surface 15R shown in FIG.

  Since the length of the inner circular cylindrical portion 12R is formed to be less than 1/5 of the length of the cylindrical light guide member 18R, as shown in FIG. 5, among the light rays emitted from the LED 7R, The light beam L1 that is reflected on the inner wall surface 12Ra of the inner circular cylinder portion 12R is reflected at least three times by the inner wall surface 12Ra and the inner wall surface 15R before reaching the illumination surface 11Ra.

  Therefore, the amount of light that reaches the center point P of the illumination surface 11Ra is weak among the light rays that are reflected by the inner wall surface 12Ra of the inner circular cylinder portion 12R.

  Further, due to the directivity characteristics of the LED 7R, the amount of light emitted by the LED 7R becomes weaker as the polar angle θ in the light emission direction approaches 0 ° to 90 °, and is therefore reflected by the inner wall surface 12Ra of the inner circular cylindrical portion 12R. Thus, the light reaching the illumination surface 11Ra has a smaller amount of light and can be ignored.

In addition, as shown in FIG. 5, the light beam that is reflected on the inner peripheral surface of the inner rectangular tube portion 14R among the light beams emitted from the LED 7R reaches the inner surface 12Ra before reaching the illumination surface 11Ra. And it is reflected twice (light ray L2) or reflected once (light ray L3) by the inner peripheral surface of the inner side square cylindrical portion 14R. This also applies to the inner circular cylindrical portion 12L.
<Dispersion of light rays by the inner rectangular tube portion 14R>
FIG. 6 is a perspective view mainly illustrating the cylindrical light guide member 18R.

  First, based on FIG. 6, a light beam having one reflection on the inner peripheral surface of the inner rectangular tube portion 14 </ b> R will be described.

Among the light rays emitted from the light emitting point O, the light rays that are reflected once on the inner peripheral surface of the inner rectangular tube portion 14R and then converge on the center point P of the illumination surface 11Ra are azimuth angles as shown in FIG. φ is radiated in the directions of φ = 0 °, 90 °, 180 °, and 270 °, and at points E, F, G, and H on the intersecting lines 17Ra, 17Rb, 17Rc, and 17Rd of the inner side rectangular tube portion 14R, respectively. 4 rays that are reflected and converged to the central point P;
As shown in FIG. 6B, the azimuth angle φ is radiated in the directions of φ = 45 °, 135 °, 225 °, and 315 °, respectively, on the inner wall surfaces 15Ra, 15Rb, 15Rc, and 15Rd of the inner rectangular tube portion 14R. There are a total of 8 rays, 4 rays that are reflected at each point Q, R, S, T and converge at the central point P.

  The light beams emitted in the direction of the azimuth angle φ other than these eight light beams are not focused on the central point P of the illumination surface 11Ra by one reflection on the inner peripheral surface of the inner rectangular tube portion 14R. This will be described with reference to FIG.

  FIG. 7A is a perspective view of the cylindrical light guide member 18R, and FIG. 7B is a front view of the cylindrical light guide member 18R of FIG. 7A viewed from the z direction.

  For example, as shown in FIG. 7, a light beam radiated in the direction of the azimuth angle φ satisfying the azimuth angle 0 ° <φ <90 ° is reflected once at a point Q on the inner wall surface 15Ra, and then the illumination surface 11Ra. It reaches the upper point R and does not converge to the central point P.

  Next, based on FIG. 8, a description will be given of a light beam having two or more reflections on the inner peripheral surface of the inner rectangular tube portion 14R. FIG. 8 is a front view of the cylindrical light guide member 18R viewed from the z direction.

  As shown in FIG. 8 (a), in the case of the inner side rectangular tube portion 14R having a square cross-sectional shape in the longitudinal direction of the present embodiment, the reflection is focused on the central point P of the illumination surface 11Ra in two reflections. Rather, as shown in an example in FIG. 8B, at least three reflections are required to focus on the central point P of the illumination surface 11Ra.

  If the number of reflections is 3 or more, the amount of reflected light is so weak that it is neglected and the total of 4 rays reflected at points E, F, G, H and 4 rays reflected at points Q, R, S, T. Light rays other than the eight light rays are not focused on the central point P of the illumination surface 11Ra.

From the above description, if the light beam reflected three times or more is ignored, the azimuth angle φ is radiated in the directions of φ = 0 °, 90 °, 180 °, and 270 °, and the intersecting lines of the inner rectangular tube portion 14R respectively. Four rays that are reflected at the points E, F, G, and H on 17Ra, 17Rb, 17Rc, and 17Rd and converge to the central point P;
The azimuth angle φ is radiated in the directions of φ = 45 °, 135 °, 225 °, and 315 °, and the respective points Q, R, S, and the like on the inner wall surfaces 15Ra, 15Rb, 15Rc, and 15Rd of the inner rectangular tube portion 14R, respectively. Only a total of 8 rays, 4 rays reflected at T and focused on the central point P, are focused on the central point P on the illumination surface 11Ra.

  The reflected light at these points E, F, G, and H and the reflected light at points Q, R, S, and T have different optical path lengths from the light emitting point O to the central point P of the illumination surface 11Ra. It is not always the phase, and these lights interfere with each other and do not strengthen each other, but in the case of the same phase, these eight rays strengthen each other, and the center point P of the illumination surface 11Ra is the brightest illumination. Is done.

  In this way, eight rays of the reflected light at the points E, F, G, and H and the reflected light at the points Q, R, S, and T among the rays that are reflected once or twice and reach the illumination surface 11Ra. Only the central point P is reached, and the light emitted at other azimuth angles is dispersed to points other than the central point P.

  By the way, as described above, in the cylindrical light guide members 8L and 8R of the conventional example, light beams in an arbitrary azimuth angle φ direction are focused on the central point P of the illumination surface 11Ra.

  In addition, in the cylindrical light guide members 8L and 8R of the conventional example, it is described that the light beam having the number of reflections of 2 or more is focused on the center point P in the same manner as described above.

  Therefore, the cylindrical light guide members 18L and 18R whose longitudinal cross-sectional shape of the present embodiment is partly square compared to the conventional cylindrical light guide members 8L and 8R whose longitudinal cross-sectional shape is a circle are The light beam is difficult to focus on the central point P of the illumination surface 11Ra and is dispersed around the central point P.

  For this reason, it becomes difficult to light the center part of the direction indication display parts 11L and 11R seen from the passenger compartment side, and the direction indication display parts 11L and 11R have good appearance.

As described above, the dispersion of the light beam by the cylindrical light guide member 18R (the light beam does not converge on the central point P on the illumination surface 11Ra) has been described, but this is also described for the cylindrical light guide member 18L.
<Effects of Example>
By making the longitudinal cross-sectional shape of the inner peripheral surfaces of the inner side square cylindrical portions 14L and 14R partly square, light is dispersed around the center portions of the direction indication display portions 11L and 11R, and the direction indication display portion It is possible to prevent the light rays from being focused on the central portions of 11L and 11R, and to prevent the central portions of the direction indication display portions 11L and 11R from flashing.

  For this reason, when the direction indication display portions 11L and 11R are viewed from the passenger compartment side, the direction indication display portions 11L and 11R do not light up and look good.

  By the way, the longitudinal cross-sectional shape of the outer peripheral surface is longer than that of the cylindrical light guide member in which the longitudinal cross-sectional shape of the outer peripheral surface is circular and the longitudinal cross-sectional shape of the inner peripheral surface is also circular. In the case of a cylindrical light guide member having a circular shape and a square cross-sectional shape in the longitudinal direction of the inner peripheral surface, a thick portion is formed between the inner peripheral surface and the outer peripheral surface, and the cylindrical guide The amount of the optical member increases.

  Therefore, as described above, the inner surface 12Ra of the inner wall surface 12Ra crosses in the longitudinal direction in the inner circular tube portion 12R that does not greatly affect the light quantity of the light guided to the direction indication display portions 11L and 11R because the number of reflections is three or more. By making the surface shape a circular shape, an increase in cost due to an increase in the amount of members can be suppressed.

  Furthermore, since the inner wall surface 15R is composed of planar inner wall surfaces 15Ra, 15Rb, 15Rc, and 15Rd, it can be easily molded by injection molding or the like.

  The embodiment of the best mode of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and the design does not depart from the gist of the present invention. Such modifications are included in the present invention.

  In the present embodiment, the inner and outer diameters of the cylindrical light guide members 18L and 18R are not specifically mentioned, but the inner and outer diameters may be changed depending on the convenience of press molding such as injection molding. May be expanded or contracted in the longitudinal direction.

  Moreover, although the inner side square cylinder part 14R whose longitudinal direction cross-sectional shape is a square was used, regular n square (n> = 3, n is a natural number) may be sufficient. Generally, as long as it is a cylindrical light guide member that does not have continuous rotational symmetry with respect to the optical axis, the longitudinal cross-sectional shape may be any shape.

  However, when the cross-sectional shape in the longitudinal direction is a regular n-gon, the light rays in the 2n azimuth direction are focused on the central point P. Therefore, as the value of n increases, the dispersion effect of the light from the central point P is reduced. It will fade.

  Therefore, it is appropriate that the value of n is 3 to 6.

  The cylindrical light guide member 18R has been described above as an example, but the same applies to the cylindrical light guide member 18L.

FIG. 1 is an exploded perspective view of a conventional combination meter device. FIG. 2A is a perspective view mainly illustrating a cylindrical light guide member of a conventional example, and FIG. 2B is a cross-sectional view taken along line AA in FIG. FIG. 2 shows how light rays are focused on the center point of the illumination surface. FIG. 3 is an exploded perspective view of the combination meter device according to the embodiment. FIG. 4A is a perspective view mainly illustrating the cylindrical light guide member of the embodiment, and FIG. 4B is a cross-sectional view taken along line BB in FIG. FIG. 5 is a cross-sectional view taken along the line C-C of the cylindrical light guide member of the embodiment shown in FIG. 4A, where the first reflection is performed in the inner circular tube portion and the inner rectangular tube. It is a figure explaining the difference in the frequency | count of reflection with the case where 1st reflection is performed in a part. FIG. 6 is a perspective view mainly illustrating the cylindrical light guide member of the embodiment. In particular, FIG. 6A shows the state of four light beams that are reflected once at a point on the intersection of the inner wall surfaces and converge to the center point of the illumination surface, and FIG. It shows the state of four rays that are reflected once at a point and converge to the central point of the illumination surface. Fig.7 (a) is a perspective view of the cylindrical light guide member of an Example. Moreover, FIG.7 (b) is the front view which looked at the cylindrical light guide member of Fig.7 (a) from the z direction. FIG. 7 shows a state in which the light beam that illuminates the illumination surface does not converge to the center point. FIG. 8 is a front view of the cylindrical light guide member of the embodiment as viewed from the z direction. FIG. 8A shows a state in which the light beam does not converge to the center point due to two reflections, and FIG. Represents a state in which the light beam converges to the center point only after three reflections.

Explanation of symbols

1 Combination meter device (meter device)
7L, 7R LED (light source)
11L, 11R Direction indication display part (display part)
12L, 12R Internal circular cylindrical portions 14L, 14R Internal rectangular cylindrical portions 18L, 18R Cylindrical light guide members

Claims (1)

The light emitted from the light source is guided to the display unit by interposing between a translucent display unit provided on the vehicle compartment side of the vehicle meter device and a light source that transmits and illuminates the display unit from the back side. A cylindrical light guide member that shines,
An inner circular tube portion whose inner circumferential surface has a circular cross section on the light source side, and an inner square tube portion whose inner circumferential surface has a square shape on the display portion side, and The cylindrical light guide member characterized by having.

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