Vehicle lighting

Abstract

The present invention provides a vehicle lighting device that suppresses light flux loss and enables the emission of a single thick line of light and multiple thin lines of light parallel to it. [Solution] A first reflective structure is provided in a first circumferential position on the side surface of a columnar light guide, in a first band-shaped region along the longitudinal direction of the columnar light guide. A second circumferential position on the side surface of the columnar light guide is connected to the side surface of a plate-shaped light guide so as to be aligned with the longitudinal direction of the columnar light guide. A second reflective structure is provided on the surface of the plate-shaped light guide in one or more second band-shaped regions along the longitudinal direction of the columnar light guide. The second reflective structure includes a groove containing an inclined surface continuous in the longitudinal direction of the second band-shaped region, and a plurality of reflective cuts arranged at intervals on the surface of the inclined surface along the longitudinal direction of the second band-shaped region.

Description

Technical Field

[0001] The present invention relates to a vehicle lamp that combines a columnar light guide and a plate-shaped light guide.

Background Art

[0002] In recent years, in vehicle lamps, due to the diversification of designs, the number of those that require linear and uniform light emission has been increasing. Therefore, for example, Patent Document 1 discloses a lamp in which a reflecting step is formed in a strip shape along the long-axis direction on the side surface of a rod-shaped light guide. When light is incident on this rod-shaped light guide from the proximal end side, while guiding the incident light in the long-axis direction toward the distal end side, a part of the light is reflected by the reflecting step and emitted in a direction substantially orthogonal to the long-axis direction. Thereby, linear and uniform-intensity light is emitted from the side surface of the rod-shaped light guide toward the front of the lamp.

[0003] Further, Patent Document 1 also discloses a light guide having a structure in which one side surface of a plate-shaped light guide is connected to the side surface of a rod-shaped light guide. The plate-shaped light guide is connected such that one side surface thereof coincides with the longitudinal direction of the rod-shaped light guide. Two rows of reflecting steps are provided on the side surface of the rod-shaped light guide. One reflecting step is used to emit linear light from the side surface of the rod-shaped light guide toward the front. The other reflecting step is used to make light incident from the rod-shaped light guide into the plate-shaped light guide. The plate-shaped light guide is provided with a plurality of reflecting steps in the plane and is configured to emit surface light toward the front of the lamp.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is a need for a vehicle light fixture that can produce a single thick line of light and multiple thin lines of light parallel to it. Such light emission can be achieved by using a light guide that connects a rod-shaped light guide and a plate-shaped light guide, with the rod-shaped light guide emitting a thick line of light and the plate-shaped light guide emitting multiple thin lines of light.

[0006] However, experiments conducted by the inventors revealed that the structure disclosed in Patent Document 1, which connects a rod-shaped light guide and a plate-shaped light guide, has a low utilization rate of luminous flux, making it difficult to emit light from the rod-shaped light guide with a thick, line-shaped, high brightness. Since vehicle lighting fixtures must achieve the light distribution specified by regulations, a decrease in the luminous flux utilization rate of a columnar light guide makes it difficult to achieve the predetermined light distribution.

[0007] According to the inventors, in the structure disclosed in Patent Document 1, which connects a rod-shaped light guide and a plate-shaped light guide, the reason for the low utilization rate of the luminous flux is thought to be that some of the light passes through the reflective steps formed on the side surface of the rod-shaped light guide, resulting in a loss of luminous flux. For example, if a stepped pattern of irregularities is provided as the reflective steps, some of the light is reflected by the reflective steps and emitted in the desired direction, but some of the light passes through the reflective steps and is emitted in the opposite direction. The light emitted in the opposite direction cannot be utilized, and the overall luminous flux utilization rate of the vehicle lighting device decreases.

[0008] Furthermore, when using rod-shaped or plate-shaped light guides to emit line-shaped light, brightness unevenness generally occurs due to differences in the optical path length of the light from the light source. Specifically, the amount of light emitted is relatively reduced at the tip, where the optical path length from the light source is longer, compared to the position where the optical path length from the light source is shorter. Therefore, a structure is needed that minimizes the loss of light beam in the columnar light guide while guiding the light to the tip, which is far from the light source.

[0009] The object of the present invention is to provide a vehicle light fixture that suppresses light flux loss and can realize a single thick line of light emission and one or more thin lines of light emission parallel to it. [Means for solving the problem]

[0010] A vehicle light fixture according to one aspect of the present disclosure includes a columnar light guide, a plate-shaped light guide connected to the circumferential side surface of the columnar light guide, and a light source that incidents light on the end of the columnar light guide. A first reflective structure is provided in a first band-shaped region along the longitudinal direction of the columnar light guide at a first circumferential position on the side surface of the columnar light guide, and the side surface of the plate-shaped light guide is connected along the longitudinal direction of the columnar light guide at a second circumferential position on the side surface of the columnar light guide. A second reflective structure is provided on the surface of the plate-shaped light guide in one or more second band-shaped regions along the longitudinal direction of the columnar light guide. The second reflective structure includes a groove including an inclined surface continuous in the longitudinal direction of the second band-shaped region, and a plurality of reflective cuts arranged at intervals on the surface of the inclined surface along the longitudinal direction of the second band-shaped region. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a vehicle lighting device that suppresses light flux loss and can realize a single thick line of light emission and multiple thin lines of light emission parallel to it. [Brief explanation of the drawing]

[0012] [Figure 1] (a) to (c) are a front view, a perspective view, and a cross-sectional view AA of a vehicle lighting device 1 according to an embodiment of the present invention. [Figure 2] View from arrow B in Figure 1(c). [Figure 3] View from arrow C in Figure 1(a). [Figure 4] View from arrow D in Figure 1(b). [Figure 5] (a) is a top view of the vehicle lighting device of the embodiment, and (b) and (c) are enlarged views of the second reflective structure of the vehicle lighting device of the embodiment. [Figure 6] Enlarged view of Figure 1(c). [Figure 7] (a) is a photograph taken from the front of the vehicle lamp 1 of the embodiment when it emits light, (b) is a diagram showing the light emission state of the vehicle lamp 1 of the embodiment calculated by simulation, and (c) is an enlarged perspective view of the columnar light guide of the vehicle lamp of the comparative example.

Mode for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

[0014] The vehicle lamp of the present embodiment is a lamp that realizes a single thick line-shaped light emission and one or more thin line-shaped light emissions parallel thereto.

[0015] FIGS. 1(a) to (c) are a front view, a perspective view, and an A-A cross-sectional view of the vehicle lamp 1 of the present embodiment. FIG. 2 is a view taken in the direction of arrow B in FIG. 1(c), FIG. 3 is a view taken in the direction of arrow C in FIG. 1(a), and FIG. 4 is a view taken in the direction of arrow D in FIG. 1(b). FIG. 5(a) is a top view of the vehicle lamp, and FIGS. 5(b) and (c) are enlarged views of the second reflection structure. FIG. 6 is an enlarged view of FIG. 1(c).

[0016] Note that FIGS. 3 and 5(b) and (c) are views of the second reflection structure 35 on the back side from the upper surface of the plate-shaped light guide 30 through the plate-shaped light guide 30.

[0017] The xyz directions orthogonal to FIGS. 1 to 6 are shown. The vehicle lamp 1 emits light forward (y direction).

[0018] As shown in FIGS. 1(a) to (c), the vehicle lamp 1 includes a columnar light guide 20, a plate-shaped light guide 30 connected to the circumferential side surface of the columnar light guide 20, and a light source 10. The longitudinal direction of the columnar light guide 20 coincides with the x direction.

[0019] As shown in FIGS. 1(c) and 2, a first strip region 21 is provided along the longitudinal direction of the columnar light guide 20 at a first position in the circumferential direction on the side surface of the columnar light guide 20 (a position in the -y direction with respect to the central axis of the columnar light guide 20). The first strip region 21 is provided with a first reflection structure 21a that reflects light guided in the columnar light guide 20 in the y direction.

[0020] Further, at a second position in the circumferential direction on the side surface of the columnar light guide 20 (a position in the z direction with respect to the central axis of the columnar light guide 20), the base portion 30a of the plate-like light guide 30 is connected along the longitudinal direction of the columnar light guide 20.

[0021] As shown in FIG. 6, the thickness of the plate-like light guide 30 is thinner at a portion farther from the columnar light guide 20 than at a portion closer to the columnar light guide 20. Also, the upper surface of the plate-like light guide 30 is curved in the yz plane such that the tip 30b on the side not connected to the columnar light guide 20 is located behind (-y direction) the columnar light guide 20. In the present embodiment, the upper surface of the plate-like light guide 30 is curved at an angle θ5 (= 60 degrees) with respect to the z axis. Note that the bending angle θ5 is not limited to 60 degrees with respect to the z axis, and can be designed to a desired angle within a range of, for example, 30 degrees to 60 degrees.

[0022] As shown in FIGS. 1(a) to (c), FIG. 3, and FIG. 4, one or more second strip regions 31 are provided on the surface (-z direction side surface) of the plate-like light guide 30 along the longitudinal direction (x direction) of the columnar light guide 20. Here, seven second strip regions 31 are provided.

[0023] As shown in FIGS. 3 and 6, the second strip region 31 is provided with a second reflection structure 35 that reflects light guided in the plate-like light guide 30 in the y direction.

[0024] The second reflective structure 35 includes a groove 32 that is inclined with respect to the surface of the plate-shaped light guide 30 and includes inclined surfaces 32a and 32b that are continuous in the longitudinal direction of the second band-shaped region 31, and a plurality of reflective cuts 33 provided on the inclined surface 32a. The reflective cuts 33 have a substantially V-groove shape that protrudes toward the inside of the plate-shaped light guide 30, and the tip has a curved shape. The reflective cuts 33 reflect light that is guided within the plate-shaped light guide 30. The depth direction (protrusion direction) of the reflective cuts 33 is forward (y direction). The angles of the inclined surfaces 33a and 33b that constitute the reflective cuts 33 will be described later.

[0025] Multiple reflective cuts 33 are arranged at intervals along the longitudinal direction of the second band-shaped region 31 on the surface of the inclined surface 32a.

[0026] The cross-sectional shape of the groove 32 is a triangle with rounded corners, as shown in Figures 3 and 6. The inclined surface 32a, on which the reflection cut 33 is provided, is formed in a direction that reflects forward (y-direction) the light that reaches the inclined surface 32a from a predetermined first direction among the light guided inside the plate-shaped light guide 30.

[0027] Specifically, for example, as shown in Figure 6, the inclined surface 32a is formed to form an angle θ3 (=3 degrees) with respect to the z-axis, and the inclined surface 32b is formed to form an angle θ4 (=10 degrees) with respect to the y-axis.

[0028] On the other hand, the reflection cut 33 is designed to reflect forward (y-direction) light that reaches the reflection cut 33 from a predetermined direction different from the first direction, out of the light guided inside the plate-shaped light guide 30.

[0029] Specifically, the shape of the reflective cut 33 is a triangular groove (V-groove) with rounded corners in cross-section, as shown in Figure 3, and the major axis of the reflective cut 33 is in a direction intersecting the longitudinal direction of the second band-shaped region 31 (here, the short direction (z direction) of the inclined surface 32a). The reflective cut 33 has inclined surfaces 33a and 33b, as shown in Figures 5(b) and (c).

[0030] Specifically, as shown in Figures 5(b) and (c), the inclined surface 33a is formed to make an angle θ1 (= approximately 101 degrees) with respect to the x-axis, and the inclined surface 33b is formed to make an angle θ2 (= approximately 143 to 149 degrees) with respect to the x-axis.

[0031] As shown in Figure 5, the depth of the reflection cut 33 of the second reflection structure 35 is designed such that the reflection cut 33 in the part of the second band-shaped region 31 that is farther from the light source 10 is deeper than the reflection cut 33 in the part of the second band-shaped region 31 that is farther from the light source 10. Specifically, for example, the depth of the reflection cut 33 in the part of the second band-shaped region 31 that is farther from the light source 10 (Figure 5(c)) is approximately 0.2 mm, while the depth of the reflection cut 33 in the part of the second band-shaped region 31 that is farther from the light source 10 (Figure 5(b)) is approximately 0.3 mm.

[0032] Furthermore, the depth of the grooves 32 of the second reflective structures 35, which are provided in each of the multiple second band-shaped regions 31, is designed so that the second band-shaped regions 31 closer to the columnar light guide 20 are deeper than the second band-shaped regions 31 further from the columnar light guide 20.

[0033] Because the reflective cuts 33 and grooves 32, which have greater depth, have larger reflective surfaces than the reflective cuts 33 and grooves 32, which have less depth, the reflectivity of the guided light within the plate-shaped light guide 30, which decreases in intensity as it moves away from the light source, can be increased. Therefore, the amount of reflected light can be made uniform in the part of the plate-shaped light guide 30 that is close to the light source 10 and the part that is far from the light source 10.

[0034] On the other hand, the first reflective structure 21a is a structure in which bumps and dips are arranged along the longitudinal direction of the first strip-shaped region 21. The height of the bumps and dips of the first reflective structure 21a is designed to be higher in the part of the first strip-shaped region 21 that is further from the light source 10 than in the part that is closer to the light source 10.

[0035] As a result, the first reflective structure 21a, which has a large height of irregularities, has a larger reflective surface than the part of the first reflective structure 21a with a small height of irregularities. Therefore, the reflectivity of the guided light within the columnar light guide 20, which decreases in intensity as it moves away from the light source, can be increased. Thus, the amount of reflected light can be made uniform in the part of the columnar light guide 20 that is close to the light source 10 and the part that is far from the light source 10.

[0036] Next, we will explain the effects of each part on the light emitted from the light source 10.

[0037] Light emitted from the light source 10 enters the columnar light guide 20 facing the light source 10 from its end face and is repeatedly reflected off the inner surface of the columnar light guide 20, guiding it in the x-direction.

[0038] Of the light guided within the columnar light guide 20, the light that reaches the position of the first band-shaped region 21 on the side surface of the columnar light guide 20 is reflected in the y-direction (forward) by the irregularities of the first reflective structure 21a formed in the first band-shaped region 21. As shown in Figure 1(c), the light reflected in the y-direction (forward) passes through the side surface of the columnar light guide 20 that is opposite to the first band-shaped region 21 where the first reflective structure 21a is provided, and is emitted in the y-direction (forward).

[0039] The height of the irregularities in the first reflective structure 21a is designed to be higher in the part of the first band-shaped region 21 that is further from the light source 10 than in the part that is closer to the light source 10 in the longitudinal direction. As a result, the proportion of reflected light is greater in the part that is further from the light source 10. Therefore, the first reflective structure 21a of the columnar light guide 20 can emit guided light, which attenuates as the distance guided in the x direction increases, in a line shape from the columnar light guide 20 almost uniformly in the x direction.

[0040] On the other hand, of the light guided within the columnar light guide 20, the light that reaches the position where the base 30a of the plate-shaped light guide 30 on the side surface of the columnar light guide 20 is connected enters the interior of the plate-shaped light guide 30.

[0041] In this embodiment, since the columnar light guide 20 is not provided with any light-controlling structure such as a reflective structure to allow light to enter the plate-shaped light guide 30, the direction of light entering the plate-shaped light guide 30 from the columnar light guide 20 is not unidirectional but in various directions. Light that enters the interior of the plate-shaped light guide 30 is guided by being repeatedly reflected by the front and back surfaces of the curved plate-shaped light guide 30. The direction of guidance is the sum of the direction from the base 30a to the tip 30b and the x-direction, but the respective directional components are not constant.

[0042] The inclined surfaces 32a of the grooves 32 of the multiple second reflective structures 35 formed on the plate-shaped light guide 30 are formed at an angle that reflects the component of the directional light guided by the plate-shaped light guide 30 that travels from the base 30a to the tip 30b in the y-direction. On the other hand, the inclined surface 33b of the reflection cut 33 formed on the inclined surface 32a is formed at an angle that reflects the x-direction component of the light guided by the plate-shaped light guide 30 in the y-direction. As a result, the inclined surface 33b formed on the inclined surface 32a reflects the light in the y-direction, which is the sum of the component traveling from the base 30a to the tip 30b and the x-direction component.

[0043] Thus, in this embodiment, not only are there inclined surfaces 32a of the grooves 32 of the multiple second reflective structures 35, but also inclined surfaces 33a and 33b of multiple reflective cuts 33 formed at intervals on the inclined surfaces 32a, so that light guiding in various directions within the plate-shaped light guide 30 can be reflected in the y direction.

[0044] Light reflected in the y-direction by the inclined surfaces 32a of the grooves 32 of the multiple second reflective structures 35 and the inclined surfaces 33a and 33b of the reflective cuts 33 passes through the plate-shaped light guide 30 and is emitted in the y-direction from the upper surface of the plate-shaped light guide 30, as shown in Figure 1(c).

[0045] The depth of the grooves 32 of the second reflective structure 35, which are provided in each of the multiple second band-shaped regions 31, is greater in the second band-shaped region 31 closer to the columnar light guide 20 than in the second band-shaped region 31 further from the columnar light guide 20. Also, the depth of the reflection cuts 33 of the second reflective structure 35 is greater in the reflection cuts 33 of the second band-shaped region 31 further from the light source 10 than in the reflection cuts 33 of the second band-shaped region 31 closer to the light source 10 in the longitudinal direction.

[0046] Therefore, multiple second reflective structures 35 of the plate-shaped light guide 30 can emit nearly uniform line-shaped light in the x-direction with almost equal intensity.

[0047] Due to the actions of the parts described above, the vehicle light fixture 1 of this embodiment can achieve a single thick line of light emission and one or more thin lines of light emission parallel to it.

[0048] In this embodiment, the vehicle lamp 1 has only one reflective structure, the first reflective structure 21a, provided on the columnar light guide 20, and does not have a reflective structure for inducing light into the plate-shaped light guide 30. Therefore, the amount of luminous flux lost by passing through the reflective structure in the columnar light guide 20 of the vehicle lamp 1 of this embodiment can be reduced compared to a vehicle lamp that has a reflective structure for inducing light into the plate-shaped light guide 30.

[0049] Therefore, a thick, high-intensity line of light can be uniformly emitted from the columnar light guide 20, and the legal light distribution requirements can be met. Furthermore, because the light flux lost in the columnar light guide 20 is suppressed, the amount of light incident on the plate-shaped light guide 30 is also large, and a high-intensity line of light can be uniformly emitted from each of the multiple second reflective structures 35.

[0050] <Variation> In the above-described embodiment, the length of the thick, high-intensity line of light emitted from the columnar light guide 20 and the length of one or more line-shaped lights emitted from the plate-shaped light guide 30 are the same. However, it is also possible to configure the plate-shaped light guide 30 to emit one or more line-shaped lights only partially, thereby changing the design of the emitted light of the vehicle lamp 1.

[0051] When partially emitting a line of light from the plate-shaped light guide 30, the second reflective structure 35 provided on the plate-shaped light guide 30 only needs to be provided in the area where the line of light is to be emitted.

[0052] <Industrial application fields> The vehicle lighting device 1 of this embodiment can be used as a position lamp, daytime running light (DRL), front and rear turn signal lamp, tail lamp, stop lamp, etc. [Examples]

[0053] An embodiment of the vehicle lighting device of the present invention will be described. As an example, a vehicle light fixture 1 with the structure of the embodiment described above was manufactured. The columnar light guide 20 and the plate-shaped light guide 30 were made of polycarbonate. The chromaticity of the light emitted from the light source 10 is X=0.557, Y=0.410 in chromaticity coordinates.

[0054] On the other hand, as shown in Figure 7(c), a comparative vehicle lamp was manufactured in which, in addition to the first reflective structure 21a, a light incidence reflective structure 22 for inducing light into the plate-shaped light guide 30 was provided on the columnar light guide 20. The other structures of the comparative vehicle lamp were the same as those of the example.

[0055] Figure 7(a) shows a photograph taken from the front of the vehicle light fixture 1 of the embodiment with the light fixture illuminated. Figure 7(b) also shows the illumination state of the vehicle light fixture 1 of the embodiment as calculated by simulation.

[0056] As shown in Figures 7(a) and (b), the vehicle light fixture 1 of the embodiment emitted a line of light with high brightness and nearly uniform brightness in the x-direction from the columnar light guide 20, and emitted multiple lines of light with uniform brightness in the x-direction from the plate-shaped light guide 30.

[0057] Furthermore, when the brightness of the light beam emitted from the columnar light guide 20 in the forward direction (y-direction) was measured, the vehicle lamp 1 of the example measured 99.65 lumens, while the vehicle lamp of the comparative example measured 90.23 lumens. The light incident from the columnar light guide 20 to the plate-shaped light guide 30 measured 5.44 lumens for the example and 7.34 lumens for the comparative example.

[0058] In other words, in the vehicle lighting fixture 1 of the embodiment, the screen luminous flux emitted from the columnar light guide 20 increased by 9.42 lumens compared to the comparative example, while the luminous flux incident on the plate-shaped light guide 30 decreased by only 2.10 lumens, resulting in an improvement in the overall light emission efficiency of the vehicle lighting fixture.

[0059] Thus, the vehicle lamp 1 of the embodiment can improve the overall luminous efficiency of the lamp while minimizing the loss of luminous flux. [Explanation of Symbols]

[0060] 1. Vehicle lighting fixtures 10 light source 20 Columnar light guide 21 First Zone Region 21a First reflection structure 22 Reflective structure for light incidence 30 Plate-shaped light guide 30a base 30b tip 31. Second Zone Region 32 Groove 32a Slope 32b Slope 33 Reflective Cut 33a Slope 33b Slope 35. Second Reflection Structure

Claims

1. The device comprises a columnar light guide, a plate-shaped light guide connected to the circumferential side surface of the columnar light guide, and a light source that incidents light on the end of the columnar light guide. A first reflective structure is provided at a first circumferential position on the side surface of the columnar light guide, in a first band-shaped region along the longitudinal direction of the columnar light guide, which reflects light guiding through the interior of the columnar light guide toward a predetermined forward direction. At a second circumferential position on the side surface of the columnar light guide, the end of the plate-shaped light guide is connected so as to be aligned with the longitudinal direction of the columnar light guide. The surface of the plate-shaped light guide is provided with a second reflective structure in one or more second band-shaped regions along the longitudinal direction of the columnar light guide, which reflects light guiding through the interior of the plate-shaped light guide toward the forward direction. The second reflective structure includes a groove containing an inclined surface continuous in the longitudinal direction of the second strip-shaped region, and a plurality of reflective cuts arranged at intervals along the longitudinal direction of the second strip-shaped region on the surface of the inclined surface. A vehicle lighting device characterized by the following features.

2. The vehicle lamp according to claim 1, characterized in that the reflective cut of the second reflective structure is a groove with a triangular cross-section, and the major axis of the reflective cut is in a direction intersecting the longitudinal direction of the second strip-shaped region.

3. The vehicle lamp according to claim 1, characterized in that the depth of the reflection cut of the second reflection structure is deeper in the portion of the second strip-shaped region that is further from the light source than in the portion of the second strip-shaped region that is closer to the light source in the longitudinal direction.

4. The plate-shaped light guide is provided with multiple of the second band-shaped regions arranged side by side. The vehicle lamp according to claim 1, characterized in that the depth of the grooves of the second reflective structure provided in the plurality of second strip-shaped regions is deeper in the second strip-shaped region closer to the columnar light guide, as well as in the second strip-shaped region further from the columnar light guide.

5. The vehicle light fixture according to claim 1, characterized in that the thickness of the plate-shaped light guide is thinner in the portion farther from the columnar light guide than in the portion closer to the columnar light guide.

6. The vehicle light fixture according to claim 1, characterized in that the plate-shaped light guide has a curved main plane.

7. The vehicle lamp according to claim 1, wherein the first reflective structure has a structure in which irregularities are arranged along the longitudinal direction of the first strip-shaped region, and the height of the irregularities of the first reflective structure is higher in the portion of the first strip-shaped region that is further from the light source than in the portion that is closer to the light source in the longitudinal direction of the first strip-shaped region.

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