JP2019192440A - Light guide - Google Patents

Abstract

To provide a rod-like light guide that prevents unevenness in lightness and hardly deforms in molding.SOLUTION: There is provided a rod-like light guide which has a plate-like attachment rib (22) formed, the light guide having the attachment rib (22) formed to a substantially overall length in a length direction of the light guide, and also having the other plate-like deformation-preventive rib (23) formed to the substantially overall length of the light guide body in the length direction. The deformation-preventive rib (23) is formed on the opposite side from the attachment rib (22), and in the same shape with the deformation-preventive rib (23), so heat radiation is balanced in cooling for injection molding and unintended deformation can be prevented. Further, both the ribs (22, 23) are formed to the overall length in the length direction to prevent unevenness in lightness in the length direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a light guide, and more particularly to a rod-shaped light guide used for a vehicular lamp.

  Conventionally, in a vehicular lamp such as a tail lamp or a clearance lamp, a configuration including a light guide has been often adopted. When a rod-shaped light guide is arranged inside the lamp, a mounting rib is formed on the light guide body in order to fix it at a predetermined position of the lamp body (for example, Patent Document 1).

JP 2006-119273 A

  However, if the mounting rib is formed only in a part of the rod-shaped light guide body in the longitudinal direction, light leakage easily occurs at the rib portion, and unevenness in brightness in the longitudinal direction of the light guide is generated. For this reason, if it is going to form a rib over the full length of a longitudinal direction, this time, when cooling by injection molding, the whole heat dissipation will become unbalanced by the rib, and it will be shrunk | distributed unevenly and it will be easy to raise | generate a deformation | transformation (warp).

  In view of such circumstances, an object of the present invention is to provide a rod-shaped light guide that prevents unevenness in brightness and is less likely to be deformed during molding.

  In order to achieve the above object, according to an aspect of the present invention, there is provided a rod-shaped light guide formed with a plate-shaped mounting rib, and the mounting rib has a substantially entire length in a longitudinal direction of the light guide. The plate-shaped deformation preventing rib is formed over the substantially entire length in the longitudinal direction.

  According to this aspect, since the rib is formed over substantially the entire length of the light guide in the longitudinal direction, uneven brightness in the longitudinal direction is not generated. In addition, since the deformation preventing ribs balance the heat radiation as a whole when cooling the injection molding, unintended deformation is unlikely to occur.

  Preferably, the deformation preventing rib is formed on the opposite side of the mounting rib. According to this aspect, the two ribs are arranged in a well-balanced manner, and the heat radiation is balanced, so that unintended deformation hardly occurs.

  Preferably, the thickness of the deformation-preventing rib is substantially the same as the thickness of the mounting rib. According to this embodiment, the balance of heat dissipation becomes better and deformation is less likely to occur.

  Preferably, the width of the deformation preventing rib in the horizontal direction perpendicular to the thickness direction and the longitudinal direction of the mounting rib is substantially the same as the width of the mounting rib. According to this embodiment, the balance of heat radiation is improved, and deformation is less likely to occur.

  Preferably, the cross-sectional shape perpendicular to the longitudinal direction including the mounting rib and the deformation preventing rib is symmetrical. According to this aspect, the cross-sectional symmetric shape has a good balance of heat dissipation and is less likely to be deformed.

  Preferably, aluminum deposition is performed on at least one surface of the mounting rib and the deformation preventing rib. According to this embodiment, light leakage from the rib portion can be suppressed by aluminum vapor deposition, and the optical performance can be maintained high.

  As is apparent from the above description, according to the present invention, it is possible to provide a rod-shaped light guide that prevents unevenness in brightness and is difficult to be deformed during molding.

It is a schematic front view of a vehicular lamp provided with the light guide according to the first embodiment. It is sectional drawing along the II-II line of FIG. It is sectional drawing along the III-III line of FIG. It is a perspective view of the light guide concerning a 1st embodiment. It is a schematic front view of a vehicle lamp provided with the light guide which concerns on 2nd Embodiment. It is sectional drawing along the VI-VI line of FIG. It is a perspective view of the light guide which concerns on 2nd Embodiment. It is sectional drawing along the VIII-VIII line of FIG. It is explanatory drawing for demonstrating the effect of the light guide which concerns on 2nd Embodiment.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The embodiments do not limit the invention but are exemplifications, and all features and combinations described in the embodiments are not necessarily essential to the invention.

(First embodiment)
FIG. 1 is a front view of a vehicular lamp 1 including a light guide according to the first embodiment, and FIG. 2 is a cross-sectional view of the vehicular lamp 1 (a cross-sectional view taken along line II-II in FIG. 1). 3 is a vertical cross-section of the vehicular lamp 1 (a cross-sectional view taken along line III-III in FIG. 1). In the present specification, directions such as up / down direction / left / right direction / front / rear direction mean directions in a posture when the vehicular lamp is mounted on the vehicle, and will be described with reference to a state in which the vehicle is viewed from the front. In each figure, each direction is described as (upper: lower: left: right: front: rear = Up: Lo: Le: Ri: Fr: Re).

  The vehicular lamp 1 is a vehicular headlamp, and is mounted on the right side of the front portion of the vehicle.

  As shown in FIG. 1, the vehicular lamp 1 includes a lamp body 2 and a transparent front cover 4 attached to an opening of the lamp body 2. The lamp body 2 and the front cover 4 define a lamp chamber S.

  The vehicular lamp 1 is a combination lamp that houses a high beam lamp A, a low beam lamp B, a turn signal lamp C, and a daytime running lamp D in a lamp chamber S.

  The high beam lamp A, the low beam lamp B, and the turn signal lamp C are arranged in the lamp chamber S side by side in the vehicle width direction. These lamps (A, B, C) may use a well-known configuration, for example, a lamp unit such as a reflection type or a projector type, and the type thereof is not limited.

  The daytime running lamp D is arranged in the upper area in the lamp chamber S along the upper side of the vehicular lamp 1.

  As shown in FIG. 2, the daytime running lamp D includes an LED light source 10 and a light guide 20.

  The LED light source 10 is an LED (light emitting diode) that emits light when supplied with power. The light source diffusely emits white light and supplies light to the light guide 20, and is arranged with its light emitting surface directed toward the left end surface that is the light incident surface of the light guide 20.

  The LED light source 10 is fixed to the heat sink 14. The heat sink 14 is a metal block with high heat dissipation, and dissipates heat generated from the LED light source 10. The heat sink 14 is configured in a shape that can be disposed at a required position in the lamp chamber S, and is fixed to the lamp body 2.

  In the lamp chamber S, an extension member 16 disposed between the LED light source 10 and the front cover 4 is disposed. The structure of the LED light source 10 is covered with an extension member 16 and hidden from the outside.

  The light guide 20 is a rod-shaped optical member, and is formed by injection molding a transparent resin such as acrylic or polycarbonate. The front side along the longitudinal direction of the light guide 20 is configured as an emission surface 20a that emits light. On the rear surface side of the light guide 20, a reflection surface 20 b having a plurality of steps 20 c for reflecting light traveling in the light guide 20 toward the emission surface 20 a is formed. Step 20c has a triangular prism shape, and a cross section along the longitudinal direction has a right triangle shape. The shape of the step is not limited to this, and may be a groove or a dot, for example.

  Light incident from the LED light source 10 travels through the light guide 20 while repeating total reflection. The light incident on the reflection surface 20b is reflected toward the emission surface 20a in step 20c and emitted from the emission surface 20a to the front of the vehicle.

  As shown in FIG. 3, a light guide holder 18 is disposed in the lamp chamber S, and the light guide 20 is supported by the lamp body 2 via the light guide holder 18.

  The light guide 20 includes a cylindrical light guide body 21, an attachment rib 22 that extends upward from the light guide body 21, and a deformation prevention rib 23 that extends downward from the light guide body 21. Composed. Each rib (22, 23) is formed at a different position in the circumferential direction from the emission surface 20a and the reflection surface 20b.

  The light guide holder 18 has a slit-shaped clamping part 18a formed on the upper wall surface and a step part 18b on the lower part, and is arranged so as to cover the light guide 20 from the back side. The light guide 20 is fixed to the light guide holder 18 by the attachment rib 22 being sandwiched by the sandwiching portion 18a and the deformation preventing rib 23 being supported by the step portion 18b at the bottom.

  An extension member 16 is disposed between the light guide holder 18 and the front cover 4, and the fixing structure of the light guide 20 is hidden by the extension member 16.

  FIG. 4 is a perspective view of the light guide 20. Step 20c of the reflecting surface 20b is omitted. At the upper part of the cylindrical light guide body 21, the mounting rib 22 extends over the entire length in the longitudinal direction, and at the lower part of the light guide body 21, that is, on the opposite side to the circumferential direction of the mounting rib 22. The deformation preventing ribs 23 are formed over the entire area. Both ribs (22, 23) are integrally formed with the light guide body 21, and the cross-sectional shape of the light guide 20 perpendicular to the longitudinal direction is the same at any position in the longitudinal direction.

  The mounting rib thickness W22 and width H22, the deformation preventing rib thickness W23 and width H23 are equal (W22 = W23, H22 = H23), and the light guide 20 has a symmetrical cross-sectional shape. Yes.

  In order to dispose the rod-shaped light guide in the lamp chamber S, it is necessary to form plate-shaped mounting ribs on the light guide body, but when the mounting ribs are formed in a part in the longitudinal direction, the ribs There is a problem that light is easily leaked at the portion and brightness unevenness in the longitudinal direction of the light guide is generated. In order to avoid this, if the rib is formed over the entire length in the longitudinal direction, heat is left in the rib formed only in one circumferential direction at the time of cooling of the injection molding. In some cases, the balance is balanced, shrinking in the direction of the ribs unevenly and warping in the longitudinal direction, causing deformation beyond the allowable range and being unable to be mounted on the lamp body.

  In the present embodiment, the mounting ribs 22 are formed over substantially the entire length in the longitudinal direction, and the deformation preventing ribs 23 are formed over substantially the entire length in the longitudinal direction. Since ribs are formed over the entire length in the longitudinal direction, unevenness in the brightness of light in the longitudinal direction can be prevented.

  Further, the mounting rib 22 and the deformation preventing rib 23 have the same shape (the same width, the same thickness, and the same length), and are formed on opposite sides in the circumferential direction, so that the two ribs (22, 23) are guided. It is arranged in a well-balanced manner in the light body main body 21, and the heat radiation is balanced during the cooling of injection molding, so that unintended deformation hardly occurs.

  In the present embodiment, both ribs (22, 23) have the same shape, but even if only the width and the thickness are the same, the effect of preventing deformation can be expected. In addition, each rib may have a shape that matches the mounting structure, such as an L-shaped or T-shaped cross section.

(Second embodiment)
FIG. 5 is a schematic front view of the vehicular lamp 101 including the light guide according to the second embodiment, and FIG. 6 is a cross-sectional view of the vehicular lamp 101 (along line VI-VI in FIG. 5). FIG. Constituent elements that are the same as or equivalent to those in the first embodiment are given the same reference numerals, and redundant descriptions are omitted.

  The vehicular lamp 101 is a clearance lamp and is mounted on the right side of the front portion of the vehicle.

  The vehicular lamp 101 includes a light guide 120 and an LED light source 10 in a lamp chamber S defined by the lamp body 2 and the front cover 4. The lamp body 2 and the front cover 4 have a shape in which the right side is curved toward the rear.

  The rod-shaped light guide 120 is curved in accordance with the shape of the lamp body 2 and has a linear shape from the left end portion to the middle as the incident surface, but gradually from the middle to the right end portion toward the rear. It has a curved shape. Thus, the light guide is not limited to a linear shape, and may have a curved shape that bends along the shapes of the lamp body 2 and the front cover 4.

  The front side along the central axis Z of the light guide 120 is an emission surface 120a that emits light. A reflection surface 120b having a step 120c for reflecting light traveling in the light guide 120 toward the emission surface 120a is formed on the rear surface side opposite to the emission surface 120a in the circumferential direction. Light incident from the LED light source 10 is guided in the light guide 120, and light incident on the reflection surface 120b is emitted from the emission surface 120a.

  7 is a perspective view of the light guide 120, and FIG. 8 is a transverse cross section of the light guide 120 (a cross-sectional view taken along line VIII-VIII in FIG. 5). In addition, the ratio of each thickness in FIG. 8 does not reflect the actual ratio, but schematically represents the configuration.

  As in the first embodiment, along the central axis Z of the curved light guide body 121, the mounting rib 122 is formed over the entire length at the top, and the deformation preventing rib 123 is formed over the entire length at the bottom. . The thickness W122 and the width H122 of the mounting rib, and the thickness W123 and the width H123 of the deformation preventing rib are equal (W122 = W123, H122 = H123), respectively. The cross-sectional shape of the light guide 120 orthogonal to the central axis Z is the same at any position, and the cross-sectional shape is symmetrical.

  As shown in FIG. 8, the attachment ribs 122 and the deformation prevention ribs 123 are subjected to metal vapor deposition on the surfaces, and the entire surfaces are covered with the metal vapor deposition film 30.

  The metal vapor deposition film 30 is selected from, for example, aluminum, SUS, and chromium, and the film thickness is about 100 nm. The metal vapor deposition film 30 is formed by a technique such as vacuum vapor deposition, for example, and is laminated on the surface of each rib with a substantially uniform thickness. The metal vapor deposition film 30 has a property of reflecting light, and reflects the light guided to each rib to the light guide body 121.

  FIG. 9 is an explanatory view for explaining the effect of the metal vapor deposition film. (A) shows a case without a metal vapor deposition film (comparative example), and (B) shows a case with a metal vapor deposition film (this embodiment). It is a cross-sectional view of a light guide, and an arrow shows the path | route of light.

  Light incident on the light guide 120 from the LED light source 10 is repeatedly reflected in the light guide body 121. When the metal vapor deposition film 30 is not present, the light incident on the mounting rib 122 is emitted from the flat portion as it is. When there is a metal vapor deposition film, the light incident on the mounting rib 122 is reflected by the metal vapor deposition film 30 and returns to the light guide body 121. By forming the metal vapor-deposited film 30, light leakage from the flat portion of each rib can be prevented, and deterioration of optical performance can be prevented.

  In the present embodiment, the metal vapor deposition film 30 is formed on both ribs, but even if the metal vapor deposition film 30 is formed only on one of the ribs, the optical performance of the light guide 120 is prevented from being deteriorated. The light guide 120 can maintain high optical performance.

  In the above embodiment, daytime running lamps and clearance lamps have been described, but the present invention is not limited to this, and is widely applied to various vehicle lamps such as turn signal lamps, stop lamps, cowl lamps, cornering lamps, fog lamps and the like. can do. The light source is not limited to an LED, and may be another semiconductor light emitting element such as a laser diode or organic EL (electroluminescence), an incandescent bulb, a halogen lamp, or the like.

  The preferred embodiments of the present invention have been described above. However, the above-described embodiments are examples of the present invention, and these can be combined based on the knowledge of those skilled in the art. Such forms are also within the scope of the present invention. include.

DESCRIPTION OF SYMBOLS 1,101 Vehicle lamp 10 LED light source 20, 120 Light guide 20a, 120a Output surface 20b, 120b (of light guide 20) Reflective surface 20c, 120c (of light guide 20) Step 21, 121 Light guide body 22, 122 Mounting rib 23, 123 Deformation preventing rib 30 Metal vapor deposition film H22, H23, H122, H123 Width W22, W23, W122, W123 Thickness Z Central axis

Claims (6)

A rod-shaped light guide body in which plate-shaped mounting ribs are formed,
The mounting rib is formed over substantially the entire length in the longitudinal direction of the light guide,
One plate-shaped deformation preventing rib is formed over substantially the entire length in the longitudinal direction of the light guide,
A light guide characterized by that. The deformation preventing rib is formed on the opposite side of the mounting rib.
The light guide according to claim 1. 3. The light guide according to claim 1, wherein a thickness of the deformation preventing rib is substantially the same as a thickness of the mounting rib. 4. The width of the deformation preventing rib in the horizontal direction perpendicular to the thickness direction and the longitudinal direction of the mounting rib is substantially the same as the width of the mounting rib.
The light guide according to any one of claims 1 to 3, wherein: The cross-sectional shape perpendicular to the longitudinal direction including the mounting rib and the deformation preventing rib is a symmetric shape,
The light guide according to any one of claims 1 to 4, wherein: Metal deposition is performed on at least one surface of the mounting rib and the deformation preventing rib,
The light guide according to any one of claims 1 to 5, wherein: