JPWO2017110366A1 - Vehicle lighting device - Google Patents

Abstract

  Provided is an illumination device that can uniformly emit a long light guide and can reduce the length of a harness for supplying power to a light source. In addition, there is provided an illumination device that suppresses an increase in the required number of LED substrates and eliminates problems in terms of cost, process, and design. A long light guide having a pair of end surfaces is provided, and a light incident portion having an incident surface is integrally formed on the light guide on one side surface of the light guide between the pair of end surfaces. In addition, a vehicle lighting device in which a light source is disposed so as to face the incident surface.

Description

Related applications

  This application claims the priority of Japanese Patent Application No. 2015-252314 filed on December 24, 2015, the entirety of which is cited as a part of this application by reference.

  The present invention relates to a vehicular illumination device including a long light guide and a light source.

  Patent Document 1 discloses a vehicle interior lighting device that linearly illuminates the ceiling by extending linearly along the front-rear direction on the left and right sides of the ceiling in the vehicle interior. This illuminating device includes a light guide that extends linearly and a light emitting diode (LED) that introduces light into the light guide from an end of the light guide. Further, in this document, a minute reflecting means is formed on the rear surface facing the front surface which is the light output surface of the light guide so that the light introduced into the light guide is efficiently emitted to the front surface. It is stated that it is good.

  Patent Document 2 discloses a vehicular lamp including a plurality of light sources and a single light guide capable of guiding light emitted from the plurality of light sources from one end surface. The light guide body is called a single extending element that extends in a predetermined direction and emits the light to be guided from the surface of the light guide body or the other end surface opposite to the plurality of light sources. It has a body part. The light guide is arranged at one end of the extending element so as to be branched from the extending element, and the incident surface on which light emitted from each of the plurality of light sources is incident (corresponding to the one end face) And a plurality of branch portions called a plurality of incident elements.

JP 2005-306233 A JP 2013-222540 A

  In the illumination devices described in Patent Documents 1 and 2, a light source is arranged so as to face an end surface in the longitudinal direction of a long light guide, and light emitted from the light source is taken in from the end surface. If the light source is arranged only on the end face side of one end of the light guide, if the length (extension distance) of the light guide becomes longer, the light does not reach the end face side of the other end, or the amount of light that reaches It will be insufficient, and it is difficult to emit light uniformly. In addition, when the light sources are arranged on both end faces of the light guide, the power harness connecting each light source is required for the length of the light guide, or for the length of the light guide or more. As a result, the cost increases and the workability of arranging the harness deteriorates, and design restrictions such as securing a mounting space for the harness occur. In addition, when LEDs are disposed as light sources on both end faces of the light guide, two or more substrates for mounting the LEDs are required. For this reason, since it becomes necessary to provide the fixed shape for positioning each LED board, while the cost and the assembly man-hour increase, the design restrictions accompanying the mounting space of an LED board arise.

  In view of the above, an object of the present invention is to provide an illumination device that can uniformly emit a long light guide and can reduce the length of a harness for supplying power to a light source. In addition, an object of the present invention is to provide an illuminating device that suppresses an increase in the required number of LED substrates and eliminates cost, process, and design problems.

  The vehicular lighting device according to the present invention includes a long light guide having a pair of end surfaces, and a light incident portion having an incident surface on one side surface of the light guide between the pair of end surfaces. A light source is disposed integrally with the light guide and is opposed to the incident surface.

  In the field of a vehicular illumination device using a long or large light guide, the vehicular illumination device according to the present invention has a pair of end surfaces instead of the end surfaces of the light guide due to the configuration having the light incident portion. Since the light from the light source can be introduced into the light guide from the middle part between the two, the long light guide can be made to emit light uniformly, and in addition, for example, when a plurality of light sources are arranged However, since the light sources are close to each other, the number of the substrates and the harness connecting the plurality of substrates can be reduced by making the substrates for the light sources common. In addition, since the vehicle lighting device according to the present invention has a light source in the middle of the light guide, the length of the power harness can be reduced as compared with the conventional one, and the assembly structure of the board can be abolished and saved. Excellent effects on cost, process, and design, such as space saving, can be obtained.

  In addition, when light sources are arranged at both ends of the light guide, from the point of uniformity of light emission, it is impossible to emit light near the both ends where the light sources are arranged. Although it is limited, in the vehicle lighting device according to the present invention, the light emitting range in the light guide including the vicinity of both ends of the light guide is not limited, and the light emitting range is maximized. Can be secured.

  In addition, as a conventional vehicle lighting device, only a function as an atmosphere illumination by indirect lighting has been required, but as a vehicle interior illumination by the recent vehicle lighting device has become widespread, as a functional lighting capable of direct lighting Needs are growing. According to the vehicular illumination device according to the present invention, the vehicular illumination device having added value that can cope with such functional illumination requiring a large amount of light and further lengthening and enlargement of the light guide. Can be provided.

  The light incident part is preferably formed to protrude from the one side surface of the light guide, and may further have a leg part branched into a plurality together with the structure, and an incident surface is formed on the leg part. Each is preferably formed. With this protruding structure and the configuration of the incident surface, light from the light source can be efficiently guided to the light guide. Further, the light branched from the incident surface of one leg is guided to one end surface of the light guide by the legs branched into a plurality, and the light from the incident surface of the other leg is guided to the other end of the light guide. The light can be guided toward.

  The light incident part is formed so as to protrude in a direction different from the light exiting direction from the light exiting surface that is one of the side surfaces of the light guide, so that the direction of each normal of the incident surface and the light exiting surface is Preferably they are different. With this configuration, it is possible to reduce the leaked light output rate at which light from the light incident part exits to the outside of the light guide (specifically, from the light exit surface to the outside). Furthermore, the angle formed by the normal line of the incident surface of the light entrance of the light guide and the normal line of the light output surface of the light guide is approximately 90 °. Is preferred. At this time, the leakage light output rate can be reduced most.

  The light incident part of the light guide may have a wide part with a large cross-sectional area as it approaches the connection part between the light guide and the light incident part at a base part protruding from one side of the light guide. Good. With this configuration, light can be efficiently incident from the entire root portion to the elongated main body portion of the light guide body, and the length of the light guide body can be reduced while reducing the amount of leakage light in the light incident portion. The light guide efficiency to the can be increased.

  A convex portion positioned opposite to the light incident portion may be formed on the other side surface facing the one side surface where the light incident portion is formed. By the convex portion, it is possible to avoid or suppress the light guided from the light incident portion becoming leakage light on the other side surface and being emitted to the outside of the light guide near the light incident portion.

  A plurality of recesses may be formed on the reflecting surface of the light guide opposite to the light exit surface so as to be aligned in the longitudinal direction of the light guide with a space therebetween. In the vicinity of the light portion, the concave portions may be partially arranged in a plurality of rows. With the above-described configuration of the plurality of recesses that are the reflecting means, light from the light source can be uniformly emitted over the entire light exit surface. In addition, there is a possibility of uneven brightness in the vicinity of the light incident part. By forming recesses in a plurality of rows in the vicinity of the light incident part, light is scattered in the vicinity of the light incident part. The light guide can be made to emit light uniformly.

  The light guide may have a rectangular cross-sectional shape orthogonal to the longitudinal direction. In this case, the light incident portion is formed on the first side surface, and the second side adjacent to the first side surface. The light exit surface is formed on the side surface, the reflective surface is formed on the third side surface facing the second side surface, and the convex portion is formed on the fourth side surface facing the first side surface. Preferably it is. Thereby, a light guide can be easily injection-molded.

  Any combination of at least two configurations disclosed in the claims and / or the specification and / or drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the present invention.

  The present invention will be understood more clearly from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.

It is a disassembled perspective view of the illuminating device which concerns on one Embodiment of this invention. It is a front view of the said illuminating device. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is the A section enlarged view of FIG. 3A. It is a perspective view which shows the light guide which concerns on one Embodiment. It is a perspective view which shows the other example of the said light guide. It is a perspective view which shows the light-incidence part of the light guide which concerns on one Embodiment. It is the perspective view seen from the lower part which shows a recessed part. It is a cross-sectional view of a recessed part. FIG. 3 is a transparent enlarged view of a portion C in FIG. 2. It is IX-IX sectional drawing of FIG. It is the B section enlarged view of FIG. 9A. It is a perspective view for demonstrating the extension angle with respect to the light guide of a light-incidence part. It is the figure which looked at FIG. 10A in the longitudinal direction of the light guide. It is a characteristic view which shows the relationship between the extension angle and the leaking light emission rate in the light emission surface. It is a top view for demonstrating the protrusion angle with respect to the longitudinal direction of a light guide of the leg part of a light-incidence part. It is a characteristic view which shows the relationship between a protrusion angle, the leakage light emission rate in the light emission surface, and the light guide efficiency to the main-body part of a light guide. It is a top view for demonstrating the protrusion length from the main-body part of a light guide of the branch part of a light-incidence part. It is a characteristic view which shows the relationship between protrusion length, the leak light emission rate in the light emission surface, and the light guide efficiency to the main-body part of a light guide. It is a top view for demonstrating the inclination angle with respect to the longitudinal direction of a light guide of a convex part. It is a characteristic view which shows the relationship between an inclination angle, the leakage light emission rate in the light emission surface, and the light guide efficiency to the main-body part of a light guide. It is a top view for demonstrating the amount of top line movements of the convex part from the main-body part of a light guide. It is a characteristic view showing the relationship between the amount of movement of the top line, the leaked light output rate on the light output surface, and the light guide efficiency to the main body of the light guide. It is a schematic plan view which shows the advancing direction of the light in the light-incident part periphery. It is a characteristic view of the result of having simulated the relationship between the position in the longitudinal direction of a light guide, and the luminance distribution of a light guide.

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

  FIG. 1 shows an exploded perspective view of the lighting device 1 according to the present embodiment, and FIG. 2 shows a front view of the lighting device 1. Here, the front side is the surface side that emits light from the lighting device 1. The illuminating device 1 is, for example, a skin-transmitting illuminating type illuminating device that is attached to a decoration member (ornament) such as a door trim of an automobile. The lighting device 1 includes at least a skin 100, an outer lens 200, a fastening portion 300, a front case 400, a light guide 500, a light emitting portion 600, a fixing claw 700 for attaching the light guide 500 to the front case 400, and A back case 800 is included, and these components are stacked in this order from the front side to the back side.

  The skin 100 is an outermost member that covers the front side of the lighting device 1, and the material is preferably a knit fabric, for example. However, the material of the skin 100 can be widely used as long as it transmits light. Although the illuminating device 1 of this embodiment employ | adopts the above-mentioned skin transmission type which covered the light emission side of the illuminating device 1 with the skin 100, it is not limited to this. Illumination device 1 may be, for example, a direct illumination type that is not a skin transmissive type, and when used for the ceiling of an automobile, a ceiling base material (not shown) whose surface is bonded to the surface is used as the skin. It is also possible to use a lighting device that is embedded in a hollow portion formed in a long hole shape in the ceiling base material and is cut out and the outer lens 200 described later is exposed in the vehicle interior.

  The outer lens 200 is disposed oppositely in the immediate vicinity of the light exit surface 550 of the light guide 500, as shown in the enlarged view (A) (FIG. 3B) of the A part of the III-III sectional view (FIG. 3A) of FIG. It has a function of transmitting and protecting the light guide 500. The outer lens 200 is formed, for example, by molding a transparent or translucent acrylic resin such as PMMA (polymethyl methacrylate) or a thermoplastic resin such as PC (polycarbonate). The outer lens 200 may be added with a scattering agent or colored milky white. Thereby, since the recessed part 561 formed in the reflective surface 560 of the below-mentioned light guide 500 can be blurred, since the favorable appearance as an interior material can be ensured, it is preferable.

  The fastening part 300 and the front case 400 in FIG. 1 are applied to fix the skin 100 to the lighting device 1 with the outer periphery of the skin 100 sandwiched therebetween. Each material of the fastening part 300 and the front case 400 is not particularly limited as long as this fixing can be achieved. The fastening portion 300 can be omitted when the lighting device 1 is a direct illumination type that is not a skin-transmitting type as described above, for example. In this case, the front case 400 may be the ceiling base material. A back case 800 is fastened to the front case 400 on the opposite side of the fastening portion 300. The fastening method between the front case 400 and the back case 800 is as shown in FIG. 3B. A known fastening method can be applied, for example, by fastening the fixing screw BS through TH1 and TH2.

  The light guide 500 is a member that causes incident light to be reflected on the inner surface to propagate inside, and to emit light from various places to the outside. Therefore, the light guide 500 is preferably made of, for example, a transparent thermoplastic resin that can be injection molded such as acrylic or PC, or a thermosetting resin such as silicone. However, the material of the light guide 500 is not limited to this, and a transparent material such as glass that is not a resin can also be used. As shown in FIG. 4, the light guide 500 according to the present embodiment has a long shape and is a portion between both end surfaces 511 and 512 in the longitudinal direction X, and is a side surface different from the both end surfaces 511 and 512. One light incident portion 520 is provided in the middle of a certain side surface. Note that there may be a plurality of light incident portions 520 as shown in FIG.

  As shown in FIG. 6, the light incident portion 520 is integrally formed so as to extend from one side surface 530 of the light guide 500, and is branched into a bifurcated shape at the branch portion 525, and the method is started from one side surface 530. It has the 1st leg part 521 and the 2nd leg part 522 which are the multiple (2 in this embodiment) leg part which protrudes in the direction away from a linear direction. The end surfaces of the first leg 521 and the second leg 522 are incident surfaces 523 and 524, respectively, and corresponding LEDs 610 and 611 (FIG. 1) so as to face the incident surfaces 523 and 524, respectively. ) Is arranged. The first leg portion 521 and the second leg portion 522 protrude from the side surface of the light guide so as to bend outward, and light from the LEDs 610 and 611 entering from the incident surfaces 522 and 523 is respectively reflected on the other side. The light is guided into the light guide 500 while being directed toward the legs. Specifically, the light from the incident surface 523 of the first leg 521 is guided toward the one end surface 511 (FIG. 4) of the light guide 500 by the legs 521 and 522 branched in two. Light from the incident surface 524 of the second leg 522 can be guided toward the other end surface 512 (FIG. 4) of the light guide 500. By using the light guide 500 according to the present embodiment provided with the light incident part 520 described above, a relatively short light guide used in a door or the like as well as a long light guide disposed on the ceiling of the vehicle. Even so, the present invention can be applied to a portion of the light guide that cannot secure a space for mounting the light source at both ends.

  Each of the first leg 521 and the second leg 522 in FIG. 6 has a rectangular cross section orthogonal to the light incident direction, for example, and has a constant cross-sectional area in the vicinity of the incident surfaces 523 and 524. Wide portions 526 and 527 are formed in the base portion near the connection portion 528 to the light guide 500, and the cross-sectional area perpendicular to the traveling direction of light increases as the distance from the intermediate portion approaches the connection portion 528. The wide portions 526 and 527 allow light to efficiently enter the entire base portions of the first leg portion 521 and the second leg portion 522 and the long main body portion of the light guide 500. It becomes possible to increase the light guide efficiency in the longitudinal direction X (and -X direction) of the light guide 500 while reducing the amount of light leakage at the first leg 521 and the second leg 522. Can do.

  The light guide 500 has a rectangular cross section orthogonal to the longitudinal direction X of the main body portion, for example, and is one of the light guides in which the first leg portion 521 and the second leg portion 522 are protruded. On the other side surface 540 facing the side surface 530, a convex portion 541 is integrally formed and extended. The convex part 541 is located opposite to the connection part 528, and the light guided from the first leg part and the second leg part by the convex part 541 becomes leakage light on the other side surface 540. In addition, it is possible to avoid or suppress the emission to the outside of the light guide 500 in the vicinity of the light incident part 520. Specifically, the convex portion 541 has four surfaces, and is inclined ± 20 ° with respect to the top surface and the bottom surface orthogonal to the one side surface 530 and the other side surface 540 and the side surface of the light guide. It has two side surfaces 541a and 541b that are formed. Since the light reflected by the two side surfaces 541a and 541b of the convex portion 541 is guided more efficiently in the longitudinal direction X of the light guide 500, the light guiding efficiency can be further increased and the convexity can be increased. Abnormal light emission near the light incident part 520 that frequently occurs when the part 541 is not present can be suppressed. The side surface of the convex portion 541 is planar, but may be formed so as to curve outward. According to this curved shape, the light guide efficiency can be further increased.

  The light output from the light guide 500 is made from the light output surface 550 which is one of the remaining two side surfaces of the light guide 500 orthogonal to the one side surface 530 and the other side surface 540. That is, the direction of the normal line N1 of the incident surfaces 523 and 524 of the light incident portion 520 parallel to the one side surface 530 is different from the direction of the normal line N2 of the light output surface 550. In this embodiment, both normal lines N1 and N2 form. The angle is approximately 90 °. The fourth side surface is a reflection surface 560 that faces the light exit surface 550. In FIG. 6, the light exit surface 550 forms a lower surface, and the reflection surface 560 forms an upper surface. That is, a light incident portion 520 is formed on one side surface 530 that is the first side surface, a light exit surface 550 is formed on a second side surface adjacent to the first side surface 530, and a third surface that faces the second side surface 550. A reflection surface 560 is formed on the side surface of the first side surface, and a convex portion 541 is formed on the fourth side surface 540 facing the first side surface 530. As described above, the first leg 521 and the second leg 522 are formed so as to protrude in a direction different from the light emission direction (light emission direction) from the light guide 500.

  A plurality of fine concave portions (optical patterns) 561 serving as reflecting means are arranged in the longitudinal direction X of the light guide 500 at intervals on the reflective surface 560 that is a surface facing the light exit surface 550 of the light guide 500. It is formed as follows. In the optical pattern 561, for example, as can be grasped from the perspective view seen from below shown in FIG. In the vicinity of 520, the major axis of the ellipse is inclined by about tens to hundreds of degrees with respect to the light guide direction in the light guide 500, that is, the longitudinal direction X (hereinafter, this angle is referred to as an arrangement angle It is also arranged in a predetermined pattern. As shown in FIG. 7B, the cross section perpendicular to the major axis of the prism P is a semicircular shape with a radius R. If the prism P is arranged so that the major axis thereof is perpendicular to the light guide direction, too much light is emitted from the prism P toward the outside of the light guide 500. In order to prevent this, it is preferable that the prism P is arranged to be inclined at an arrangement angle in the above-described range other than 90 ° to control the light output.

  Technically, it is possible to control how light is emitted by arranging a small prism P having a radius R adjusted to about several to several tens of μm so that the arrangement angle with respect to the longitudinal direction X is vertical. However, since the mold cost of such a small prism is expensive and a cost problem arises, and there is a limit to the minimization of the radius R due to production technology restrictions, the light emission amount as described above is adjusted. As a device, the arrangement angle of the prism P is variable with respect to the longitudinal direction X. In principle, the prism P is arranged at an arrangement angle in which the major axis direction of the prism P is perpendicular to the light guide direction. In the vicinity of the light incident part 520, in order to reduce light leakage, As described above, the arrangement angle of the prism P is changed.

  On the other hand, the radius R and the depth D of the prism P are adjusted so as to be smaller than the other portions in the vicinity of the light incident portion 520. This is because the entire light guide 500 is caused to emit light uniformly by reducing the amount of light emitted in the vicinity of the light incident portion 520. The optical pattern 561 is formed simultaneously with the injection molding of the light guide 500, for example. Specifically, a fine optical pattern such as the optical pattern 561 can be formed by processing the molding die of the light guide 500 by blasting, laser processing, etching, or the like.

  Furthermore, for example, as shown in FIG. 6, the concave portions are formed so as to be arranged in three rows only in the vicinity of the light incident portion 520. In the vicinity of the light incident part 520, there is a possibility that a brightness deviation occurs in the width direction Y orthogonal to the longitudinal direction X of the light guide 500. Therefore, by forming the concave portions so as to form a plurality of rows in the width direction Y of the light guide 500, light scattering is increased in the vicinity of the light incident portion 520, and the light guide 500 emits light uniformly. That is, it is possible to emit light uniformly from the light exit surface 550 of the light guide 500.

  The first and second leg portions 521, 522 and the convex portion 541 are unevenly distributed on the side opposite to the light exit surface side in the one side surface 530 and the other side surface 540, that is, these light guides are arranged. 6 is formed so as to be positioned substantially on the upper half side, which is the upper side in FIG. 6, and the connection portion 528 of the light incident portion 520 and the like are formed on the lower half sides of both side surfaces 530 and 540. No fitting part 580 is formed. On the other hand, in the upper half portion of the light guide 500, in addition to the light incident portion 520 and the like, a flange portion 570 protrudes outward in the same plane as the reflective surface 560 at the edge of both side surfaces 530 and 540. Thus, the light guide 500 is formed along the longitudinal direction X. With this structure, the fitting portion 580 shown in FIG. 6 of the light guide 500 is fitted into the long groove formed in the front case 400 or the ceiling base material shown in FIG. The light guide 500 can be locked to position the light guide 500 in the fitting direction, and the light exit surface 550 is substantially flush with the front side of the front case 400 or the ceiling base material in FIG. It becomes possible to improve the designability. Although the flange portion 570 of FIG. 6 is formed over almost the entire length of the light guide 500, only the portions corresponding to the light incident portion 520 and the convex portion 541 are not formed. This is to prevent the above-described function of the convex portion 541, that is, the function of improving light guiding efficiency and the function of suppressing abnormal light emission from being deteriorated.

  The light emitting unit 600 of FIG. 1 includes two light sources 610 and 611, for example, LEDs, an FPC (flexible printed circuit board) 630, and a heat sink 650. As shown in FIG. 8, which is a transmission enlarged view of part C in FIG. 2, the LEDs 610 and 611 allow the luminescence light to enter the corresponding incident surfaces 523 and 524, respectively. The LEDs 610 and 611 can be selected widely regardless of the manufacturer or the like as long as the area of the light emitting surface is the same as or smaller than the area of the incident surfaces 523 and 524. The FPC 630 is a substrate on which an electric circuit is formed by bonding an insulating flexible base film (polyimide or the like) and a conductive metal such as copper foil, and an LED substrate to which an LED is attached and which receives power supply It is. The LEDs 610 and 611 are attached to one FPC in this embodiment, but may be attached to separate FPCs.

  The heat sink 650 is made of a material having high thermal conductivity such as aluminum, copper, or iron, and has a configuration in which the area of the heat radiating surface is increased. FIG. 9B), the LED 610, 611 or the FPC 630 is disposed in contact with or near the LED 610, 611 or the FPC 630, thereby dissipating heat generated from the LEDs 610, 611. The heat sink 650 can prevent problems such as the incident surfaces 523 and 524 of the light guide 500 being melted by the generated heat and the peripheral components of the LEDs 610 and 611 being burnt. In addition, the lifetime of the LEDs 610 and 611 themselves can be prevented from being reduced due to heat generation. Here, the heat sink 650 may be omitted depending on the required brightness of the lighting device, that is, depending on the type of LED used, because such a separate heat dissipation component is not necessary.

  The fixing claw 700 is formed separately from the front case 400 and the light guide 500, and is inserted into a hole HL formed in the front case 400 as shown in FIG. It is used to fix the light guide 500 to the front case 400 by locking it to the side surface of 570 with mechanical frictional force. The material of the fixing claw 700 is not particularly limited as long as it has vibration resistance, heat resistance, and the like in order to fix the light guide 500 to the front case 400.

  The back case 800 is made of a resin such as PMMA, PC, or ABS, or another material, and functions as a housing that houses the light guide 500 and the like. The back case 800 is preferably made of a black light-shielding material so as not to cause light leakage.

  As described above, according to the illuminating device 1 according to the present embodiment, light is incident on the middle of one side surface 530 of the light guide 500 different from the both end surfaces 511 and 512 in the longitudinal direction X of the light guide 500 in FIG. By having the portion 520, the long or large light guide 500 can uniformly emit light, and the LEDs 610 and 611 in FIG. 8 are in the middle of one side surface 530 of the light guide 500. Since it exists close to the vicinity, it is possible to provide an illumination device that can reduce the length of the harness for supplying power to the LEDs 610 and 611. In addition, according to the present embodiment, since the LEDs 610 and 611 are present in the vicinity of the light incident part 520 in the middle of the light guide 500, the LEDs 610 and 611 can be mounted on one LED substrate, It is possible to provide an illuminating device that suppresses an increase in the required number of LED substrates and eliminates problems in cost, process, and design.

  In addition, when the LEDs 610 and 611 are disposed on the one end surface 511 and the other end surface 512 that are both ends of the light guide 500, light is emitted from the vicinity of both ends where the LEDs 610 and 611 are disposed in terms of light emission uniformity. However, the light-emitting range in the light guide 500 is limited, but the lighting device 1 according to the present embodiment maximizes the light-emitting range including the vicinity of both ends of the light guide 500. Can be secured.

  Next, the optimum value of the extension angle θ1 of the light incident part 520 with respect to the light guide 500 will be described. As shown in FIG. 10A, when the height direction (upward direction in the figure) Z orthogonal to both the longitudinal direction X and the width direction Y of the light guide 500 is set to a direction opposite to the light exit direction, FIG. As shown in FIG. 10B, which is a view in the −X direction, the direction Z is the extension angle θ1 = 0 °. The extension angle θ1 changes as 0 ° ≦ θ1 ≦ 90 °. When the extending angle θ1 = 0 °, the light incident portion 520 extends from the upper surface 560, and when the extending angle θ1 = 90 °, the light incident portion 520 extends from the one side surface 530.

  The light (hereinafter also referred to as leakage light) from which the light from the light incident part 520 exits from the periphery of the connection part 528 to the outside of the light guide 500 is critical in the propagation process of light that repeats total reflection inside the light guide 500. Occurs because it exceeds the corner. That is, it means that light exits beyond a critical angle from either one of two surfaces that are not parallel to the light propagation direction. Conversely, light that has repeatedly undergone total reflection between two surfaces completely parallel to the propagation direction does not exceed the critical angle and does not emit light. FIG. 10C shows the extension angle θ1 and the light exit surface 550 when the extension angle θ1 is changed from the direction parallel to the light exit direction (θ1 = 0 °) to the direction perpendicular to the light exit direction (θ1 = 90 °). The characteristic figure with the leak light emission rate in is shown. The leaked light output rate is a ratio of the leaked light in the light output direction to the entire incident light to the light guide 500. Referring to FIG. 10C, it can be seen that the leakage light emission rate tends to decrease as θ1 = 90 ° approaches the light emission direction, and the preferred angle of the extension angle θ1 has the lowest leakage light emission rate. It can be said that 75 ° ≦ θ1 ≦ 90 °. In the present embodiment, in order to completely prevent the generation of leakage light, the extension angle θ1 = 90 °, and the light incident part 520 extends so as to protrude from the one side surface 530 in the normal direction as described above. I'm out.

  Next, the optimum value of the protrusion angle θ2 of the first leg portion 521 of the light incident portion 520 with respect to the longitudinal direction X of the light guide 500 will be described. As shown in FIG. 11A, the angle formed by the side plane 521a of the wide portion 526 of the first leg 521 facing the second leg 522 and the longitudinal direction X is the protrusion angle θ2. FIG. 11B shows the relationship between the protrusion angle θ2 when the protrusion angle θ2 is changed from 15 to 60 °, the leakage light output rate at the light output surface 550, and the light guide efficiency to the main body of the light guide 500. A characteristic diagram is shown. Here, the light guide efficiency is obtained by a calculation formula of “remaining light quantity at the end of the light guide body (the one end surface 511 and the other end surface 512) / the total luminous flux emitted from the LEDs 610 and 611”. According to FIG. 11B, the leaked light output rate decreases most in the range of 25 ° ≦ θ2 ≦ 35 ° (the light guide efficiency increases most), and the leak light output rate increases as the distance from the range increases (the light guide efficiency). It can be seen that there is a tendency to decrease. Therefore, it can be said that the preferable angle of the protrusion angle θ2 is 25 ° ≦ θ1 ≦ 35 °. Therefore, in the present embodiment, the protrusion angle θ2 = 35 °. The above applies to the second leg portion 522 as well.

  Next, the optimum value of the projecting length L in the Y direction from the main body of the light guide 500 at the branching part 525 of the light incident part 520 will be described. As shown in FIG. 12A, the position where the branching portion 525 protrudes from the main body of the light guide 500 by the length of the width of the light guide 500 (for example, 5 (mm) in this embodiment) is set to L = 0. (Mm). In FIG. 12B, when the protrusion length L is changed from −2.5 to 7.5 (mm), to the protrusion length L, the leaked light emission rate at the light output surface 550, and the main body of the light guide 500. The characteristic view which shows the relationship with the light guide efficiency of is shown. According to FIG. 12B, the leaked light output rate decreases most in the range of −1 ≦ L ≦ 1 (mm) (the light guide efficiency increases most), and the leaked light output rate increases as the distance from the range increases. It can be seen that the light efficiency tends to decrease. Therefore, it can be said that the preferable range of the protrusion length L is −1 ≦ L ≦ 1 (mm). Therefore, in the present embodiment, the protruding length L = 0 (mm).

  Next, the optimum value of the inclination angle θ3 of the convex portion 541 with respect to the longitudinal direction X of the light guide 500 will be described. As shown in FIG. 13A, the angle formed between the side surface 541a of the convex portion 541 and the longitudinal direction X is the inclination angle θ3. FIG. 13B shows the relationship between the tilt angle θ3, the leaked light output rate at the light output surface 550, and the light guide efficiency to the main body of the light guide 500 when the protrusion angle θ3 is changed by 10 to 45 °. A characteristic diagram is shown. According to FIG. 13B, the leaked light output rate is the lowest (the light guide efficiency is the highest) in the range of 15 ° ≦ θ3 ≦ 25 °, preferably in the range of 18 ° ≦ θ3 ≦ 23 °, and departs from this range. It can be seen that the leakage light output rate tends to increase (light guide efficiency decreases). Therefore, it can be said that the preferable angle of the inclination angle θ3 is 18 ° ≦ θ3 ≦ 23 °. Therefore, in the present embodiment, the design is such that θ3 = 20 °. The above applies to the side surface 541b as well.

  Next, an optimum value of the amount of movement h of the top line in the −Y direction from the main body of the light guide 500 of the convex portion 541 will be described. As shown in FIG. 14A, when the intersection line 541c (FIG. 6) of the side surfaces 541a and 541b of the convex portion 541 is called the top line of the convex portion 541, the top line 541c protrudes from the main body of the light guide 500. The position where there is no h is 0 (mm). In FIG. 14B, the top line movement amount h when the top line movement amount h is changed from 1 to 7 (mm), the leaked light emission rate at the light exit surface 550, and the light guide to the main body of the light guide 500. The characteristic view which shows the relationship with efficiency is shown. According to FIG. 14B, the leaked light output rate is the lowest in the range of 1.7 ≦ h ≦ 2.8 (mm) (light guide efficiency is the highest), and the leaked light output is increased as the distance from the range is increased. It can be seen that the rate tends to increase (light guide efficiency decreases). Therefore, it can be said that a preferable range of the amount of movement of the top line h is 1.7 ≦ h ≦ 2.8 (mm). In this range, the minimum value of leakage light emission rate (maximum value of light guide efficiency) of the amount of light leaked from the top line h is 2.25 (mm). Therefore, in this embodiment, the amount of top line movement h = 2.25. (Mm).

  FIG. 15 is a schematic plan view of the traveling direction of light when using the extension angle θ1, the protrusion angle θ2, the protrusion length L, the inclination angle θ3, and the top line movement amount h described above, and FIG. Shown in FIG. 15 shows the traveling direction of light around the light incident portion 520 in FIG. 14A. In FIG. 15, light enters the light guide 500 from the light entrance 520 through the connection portion 528 without leaking from the light entrance 520 and the light guide 500 in FIG. 14A. FIG. 16 shows the relationship between the position in the longitudinal direction of the light guide 500 in FIG. 14A and the luminance distribution of the light guide 500, specifically, the intermediate portion in the longitudinal direction X of the connection portion 528 as a reference point. It is a characteristic view of the result of having simulated the relationship between the distance P in the longitudinal direction X from the said reference point, and the luminance distribution of the light guide 500 at the time. In FIG. 16, the luminance change characteristic around the reference point P = 0 (mm) is a pulsation characteristic that is almost inferior to the luminance change characteristic in other parts other than the vicinity of P = 0 (mm).

  As shown in FIGS. 15 and 16, light leakage from the vicinity of the light incident portion 520 in FIG. 14A is reduced, and dark spots and hot spots (abnormally light emitting portions that are specifically bright portions and dark portions on the light exit surface 550). These are called hot spots and dark spots, respectively). Therefore, in the illuminating device 1 of this embodiment, the illuminating device such as uneven brightness and glare due to dark spots and hot spots, which are likely to occur when the light incident portion 520 is provided in the middle of the longitudinal direction X of the light guide 500. The cause of the performance degradation in the appearance of has been eliminated. As described above, it is possible to reduce the abnormal light emission by allowing light to enter the light guide 500 from a light exit direction, that is, a direction different from the vertical direction of the light exit surface 550, preferably a direction orthogonal to this direction. The inventors of the present application have found that this is possible, and has made it possible to provide an illumination device 1 that is characterized in that light is incident from a light incident portion 520 in the middle of the long light guide 500.

  As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily understand various changes and modifications within the obvious scope by looking at the present specification. Therefore, such changes and modifications should be construed as being within the scope of the invention defined by the claims or within the scope equivalent thereto.

500 Light guide 511, 512 End face 520 Light incident part 521, 522 Leg part 523, 524 Incident face 526, 527 Wide part 528 Connection part 530 One side surface 540 Other side surface 541 Convex part 550 Light exit surface 560 Reflective surface 561 Optical pattern (plurality) Recess)
610, 611 Light source X Longitudinal direction

Claims (8)

A long light guide having a pair of end faces,
A light incident portion having an incident surface is formed integrally with the light guide on one side surface of the portion between the pair of end surfaces of the light guide, and a light source is disposed so as to face the incident surface. The vehicle lighting device.   2. The light incident portion according to claim 1, wherein the light incident portion is formed to project from the one side surface of the light guide body, has a plurality of leg portions branched, and an incident surface is formed on each of the leg portions. Vehicle lighting device.   The light incident part is formed so as to protrude in a direction different from the light exiting direction from the light exiting surface that is one of the side surfaces of the light guide, so that the direction of each normal of the incident surface and the light exiting surface is The illumination device for vehicles according to claim 1 or 2 which differs.   The angle formed by the normal line of the incident surface of the light incident portion of the light guide and the normal line of the light output surface of the light guide is approximately 90 °. The vehicle lighting device described in 1.   The light incident part of the light guide is formed with a wide part having a larger cross-sectional area as it approaches a connection part between the light guide and the light incident part at a base part protruding from one side of the light guide. Item 5. The vehicle lighting device according to any one of Items 1 to 4.   The vehicle according to any one of claims 1 to 5, wherein a convex portion that faces the light incident portion is formed on another side surface that faces the one side surface on which the light incident portion is formed. Lighting equipment.   A plurality of recesses are formed on the reflecting surface of the light guide opposite to the light exit surface so as to be aligned in the longitudinal direction of the light guide with a space therebetween. The vehicular illumination device according to claim 3, wherein the recesses are arranged in a plurality of rows.   A cross-sectional shape perpendicular to the longitudinal direction of the light guide is rectangular, the light incident portion is formed on a first side surface, and the light exit surface is formed on a second side surface adjacent to the first side surface. The formed reflective surface is formed on a third side surface facing the second side surface, and the convex portion is formed on a fourth side surface facing the first side surface. Vehicle lighting device.

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