Vehicle lighting device

A vehicle lighting device includes a light emitting unit, a holding unit, a light guide, a cover and an attachment unit. The light emitting unit has one or more light emitting elements. The holding unit holds the light emitting unit. The light guide guides light emitted from the light emitting unit and emits the light from a tip which is on a tip side opposite to a light emitting unit side. The cover has a first fixation unit to be fixed to the holding unit and a second fixation unit which has a diameter smaller than a diameter of the first fixation unit and internally fixes the light guide thereto in a state of exposing the tip. The attachment unit is formed in the second fixation unit in a shape attachable to a reflector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priorities from Japanese Patent Application No. 2013-099656, filed on May 9, 2013 and Japanese Patent Application No. 2013-114683, filed on May 30, 2013; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a vehicle lighting device.

BACKGROUND

A vehicle lighting device using a light emitting element as a light source is employed in front combination lamps and rear combination lamps. When the light emitting element is used in a lighting device, thermal management for the light emitting element is one important item. This is because the light emitting element has characteristics that light emitting efficiency is decreased due to a temperature rise of the element itself. In particular, in order to be mounted on a vehicle, the vehicle lighting device needs to maintain a function under an operating environment from a low temperature environment of −40° C. to a high temperature environment of 85° C. In this regard, the thermal management under the high temperature environment is important. In addition, the vehicle lighting device needs to be miniaturized, thereby precluding a heat radiating area from being sufficiently secured. Accordingly, the thermal management becomes more important. If a plurality of LED units previously unitized to be mountable on a board is simply mounted on a printed circuit board, the printed circuit board is increased in size, thereby resulting in an inevitably increased size of the vehicle lighting device. Incidentally, the lighting device includes those which have a light guide for guiding light emitted from the light emitting element.

If the thermal management or the fact that the printed circuit board is internally accommodated is considered, miniaturization of the vehicle lighting device cannot be achieved. As a result, an outer diameter of the vehicle lighting device is increased. An attachment unit in which the vehicle lighting device is attached to a lamp, for example, which emits the light from the vehicle lighting device, is disposed on an outer peripheral surface of the vehicle lighting device. In this case, the attachment unit is caused to have the larger outer diameter according to the diameter of the vehicle lighting device. In this regard, when the vehicle lighting device is generally attached to the lamp, a portion of the vehicle lighting device is protruded into the lamp. For this reason, an insertion port for inserting the vehicle lighting device is formed in the lamp. Since the attachment unit is attached to the lamp in the vicinity of the insertion port, the insertion port is increased in size so as to match the outer diameter of the vehicle lighting device. Therefore, if the diameter of the vehicle lighting device is increased, when a front surface of the vehicle lighting device is viewed from outside of the lamp, there is a problem in that a proportion occupied by a light non-emitting region which does not emit the light is relatively increased as compared to a light emitting region which emits the light such as the light emitting element.

The exemplary embodiments described herein aim to provide a vehicle lighting device which can decrease the proportion occupied by the light non-emitting region with respect to the light emitting region when viewed from the front.

DETAILED DESCRIPTION

Vehicle lighting devices1A to1I according to embodiments described below include a light emitting unit2, a holding unit3, a light guide4, a cover5and an attachment unit6. The light emitting unit2has one or more light emitting elements21. The holding unit3holds the light emitting unit2. The light guide4guides light emitted from the light emitting unit2and emits the light from a tip4awhich is an opposite side to the light emitting unit2side. The cover5has a first fixation unit51to be fixed to the holding unit3and a second fixation unit52which has a diameter smaller than that of the first fixation unit51and internally fixes the light guide4thereto in a state of exposing the tip4a. The attachment unit6attaches the vehicle lighting devices1A to1I to a light emitting object (lamp)100to which the light guided from the light guide4is emitted, and is formed in the second fixation unit52.

In addition, in the vehicle lighting devices1A to1I according to the embodiments, the light guide4has a cylindrical shape, and a ratio D1/D2of an outer diameter D1of the light guide4to an outer diameter D2of the second fixation unit52has a relationship of 0.1≦D1/D2≦0.9.

In addition, in the vehicle lighting devices1A,1B and1H according to the embodiments, the tip4aof the light guide4has a recess41.

In addition, in the vehicle lighting device1B according to the embodiment, the recess41has a recessed surface41awith which reflection materials42to44or scattering materials are in close contact.

In addition, in the vehicle lighting devices1A to1I according to the embodiments, the cover5to which the light guide4is fixed is attachable to and detachable from the holding unit3.

In addition, in the vehicle lighting devices1D to1H according to the embodiments, the cover5has an opening53to which the light guide4is inserted in a state of exposing the tip4a, and accommodates a portion of the light guide4and the light emitting unit2in a space S formed between the holding unit3and the cover5. In addition, the light guide4has light guide fixation portions47aand47bto be fixed to the cover5in a state of being inserted into the opening53, and has an outer diameter D12from the light guide fixation portions47aand47bto the tip4aside, which is larger than an outer diameter D11from the light guide fixation portions47aand47bto the light emitting unit2side.

In addition, in the vehicle lighting devices1D, and1F to1H according to the embodiments, the cover5has a positioning portion54which opposes the light guide4in a radial direction of the light guide4, and at least one of the positioning portions54is formed in the space S in a circumferential direction.

In addition, in the vehicle lighting devices1D to1H according to the embodiments, the light guide fixation portions47aand47bare protruded in the radial direction of the light guide4, and at least one of the light guide fixation portions47aand47bis formed in the circumferential direction.

In addition, in the vehicle lighting devices1D,1E and1H according to the embodiments, an outer diameter D13of the light guide fixation portion47ais larger than the outer diameter D12from the light guide fixation portion47ato the tip4aside, and the light guide fixation portion47ais internally fixed to the cover5inside the cover5.

In addition, in the vehicle lighting device1G according to the embodiment, the light guide fixation portion47bis externally fixed to the cover5outside the cover5.

In addition, in the vehicle lighting device1I according to the embodiment, the cover5has the opening53to which the light guide4is inserted in a state of exposing the tip4a, and accommodates a portion of the light guide4and the light emitting unit2in the space S formed between the holding unit3and the cover5. In addition, the light guide4has a light guide fixation portion47cto be fixed to the cover5in a state of being inserted into the opening53. The outer diameter D12from the light guide fixation portion47cto the tip4aside is the same as the outer diameter D11from the light guide fixation portion47cto the light emitting unit2side, and the outer diameter D13of the light guide fixation portion47cis larger than the outer diameter D12from the light guide fixation portion47cto the tip4aside.

Hereinafter, the vehicle lighting devices according to the embodiments will be described with reference to the drawings. The same reference numerals are given to the same elements in the embodiments, and description thereof will be omitted.

First Embodiment

A first embodiment will be described with reference toFIGS. 1 to 3.FIG. 1illustrates a relationship between a vehicle lighting device and a lamp according to the first embodiment.FIG. 2is a perspective view illustrating the vehicle lighting device according to the first embodiment.FIG. 3illustrates light distribution characteristics of the vehicle lighting device according to the first embodiment. InFIG. 3(FIGS. 5 and 11are also the same), an axis in a radial direction represents intensity of light emitted from the vehicle lighting device (intensity of light is stronger outward), and an axis in a circumferential direction represents an emitting angle. In addition, a solid line illustrated inFIG. 3represents the light distribution characteristics on a horizontal plane, and a one-dot chain line illustrated inFIG. 3represents the light distribution characteristics on a vertical plane orthogonal to the horizontal plane. An upward direction from the paper surface inFIG. 3represents a light emitting direction.

A vehicle lighting device1A of the present embodiment is a vehicle lighting device which is used in an exterior or an interior of a vehicle, and for example, includes a stop lamp, a tail lamp, a turn signal lamp and a fog lamp which configure front combination lamps and rear combination lamps. As illustrated inFIG. 1, in the present embodiment, the vehicle lighting device1A emits the light to a lamp100. The vehicle lighting device1A is configured to include the light emitting unit2, the holding unit3, the light guide4, the cover5and the attachment unit6. In the vehicle lighting device1A, the light emitting unit2and the holding unit3are accommodated in the cover5and the light guide4is fixed to the cover5. In the present embodiment, one vehicle lighting device1A is mounted on the lamp100. However, without being limited thereto, two or more vehicle lighting devices1A may be mounted on the lamp100.

Here, the lamp100is a light emitting object, and emits the light emitted from the vehicle lighting device1A, that is, emits the light emitted from the light guide4outward using predetermined light distribution. In the present embodiment, the lamp100emits the light outward from a vehicle (not illustrated). The lamp100is configured to include a reflector101, a lens102and a reception unit103. In the lamp100, the lens102is exposed outward from the vehicle, and the reflector101and the vehicle lighting device1A are arranged inside the vehicle.

The reflector101is formed in a concave shape, and is arranged to surround the vehicle lighting device1A. The reflector101is generally formed of a resin material, and an inner peripheral surface thereof has a reflection layer formed by using a reflection material such as aluminum. In this manner, the inner peripheral surface of the reflector101is formed as a reflection surface (mirror surface). The reflector101has an insertion port104for internally exposing the vehicle lighting device1A. A portion of a second fixation unit52(to be described later) of the cover5is inserted into the insertion port104of the reflector101, and a portion between the reflector101and the vehicle lighting device1A is sealed with a packing (not illustrated).

The lens102is a clear lens which is formed of a material having transparency, for example, in the present embodiment, a transparent colorless resin material or glass, and is adapted to close an interior of the reflector101. Since the lens102has transparency, the light emitted from the vehicle lighting device1A or the light reflected on the reflection surface of the reflector101is transmitted through the lens102and emitted outward from the lamp100, that is, emitted outward from the vehicle.

The reception unit103supports and fixes the vehicle lighting device1A to the lamp100by engaging with the attachment unit6of the vehicle lighting device1A. The reception unit103is formed to protrude to both of the lens102side and the opposite side of the insertion port104, and has a space portion103ato which the attachment unit6is inserted. The reception unit103is formed to have the number corresponding to the number of the attachment units6(to be described later), and is arranged around the insertion port104. A distance between the adjacent reception units103is set so that the attachment unit6can be inserted in the axial direction of the vehicle lighting device1A. In addition, an opening (not illustrated) which communicates with the space portion103ais formed on one lateral surface within lateral surfaces in the circumferential direction of the reception unit103.

The light emitting unit2emits the light and for example, has the light emitting element21mounted on a substrate22having heat radiation performance. The light emitting element21is a light emitting semiconductor device such as an LED and an LD. One or more light emitting elements21, in the present embodiment, a plurality of light emitting elements is directly mounted on the substrate22in series or in parallel. As illustrated inFIG. 1, each light emitting element21is electrically connected to the substrate22via a wire23. The light emitting unit2is disposed so that all light emitting elements21are surrounded by the reflector24which reflects the light emitted from each light emitting element21. The reflector24has a tilted surface24ain which an inner peripheral surface thereof is widened from the substrate22side to the light guide4side. In the light emitting unit2, in order to prevent damage to each light emitting element21and cutting of the wire23, a resin25having the transparency is filled with a space portion generated by the reflector24, that is, a light emitting container for containing each light emitting element21. In this manner, each light emitting element21is sealed with the resin. Therefore, since the plurality of light emitting elements21is accommodated in the reflector24, it is possible to decrease the light source in size and to miniaturize the substrate as compared to a case where a plurality of LED units previously unitized so as to be mountable on the substrate is mounted on the printed circuit board. The substrate22is a mounting substrate for mounting each light emitting element21and a driving substrate for mounting a drive circuit which supplies power to the light emitting unit2. The substrate22is configured so that the light guide4side serves as a component placement surface, and each light emitting element21described above and a control element (not illustrated) to control the reflector24or each light emitting element21are mounted thereon. The substrate22is configured so that an opposite side to the component placement surface serves as heat radiation surface, and is fixed in a contact state with a mount31of the holding unit3in the present embodiment. In addition, the substrate22is an insulating substrate formed of materials in which the heat generated by the light emitting element21is easily transferred, such as metal or ceramic having high heat conductivity. The substrate22is connected to a power supply member (not illustrated). The power supply member is electrically connected to an external power source (not illustrated) disposed outside the vehicle lighting device1A. Accordingly, the power of the external power source is supplied to each light emitting element21via the power supply member. Each light emitting element21may be connected to the power supply member either in parallel or in series.

The holding unit3holds the light emitting unit2and also serves as a heat radiation member which radiates heat from the light emitting unit2. Within the holding unit3, a main body32including the mount31on which the light emitting unit2is placed is configured to have a resin material. In the present embodiment, as illustrated inFIG. 1, in order to improve heat radiation performance, a heat sink33formed of a metallic material is attached to the main body32configured to have the resin material. The heat sink33is to expand a surface area exposed outward of the holding unit3. Accordingly, an area for the heat radiation is improved and a heat radiation effect is improved. The main body32and the heat sink33of the holding unit3may be integrally molded with the resin having high heat radiation.

The light guide4guides the light emitted from the light emitting unit2and emits the light to the lamp100. The light guide4is formed in a cylindrical shape and emits the light from the light emitting unit2, which is guided from the tip4aof the opposite side to the light emitting unit2side. For example, the light guide4is formed of a material having high light transmittance such as transparent acrylic resin, glass and polycarbonate. The light guide4is arranged so that the opposite side to the tip4aopposes the light emitting unit2in the axial direction. In order to guide all of the light or most of the light emitted from the light emitting unit2, the light guide4is in contact with or is optically connected to the light emitting unit2with a slight gap. That is, the light emitted from the light emitting unit2is incident through the end portion of the light emitting unit2side of the light guide4, is totally reflected inside the light guide4and is emitted outward from the tip4a, that is, emitted into the lamp100.

Here, the light guide4in the present embodiment has a recess41in the tip4a. The recess41is formed in a circular truncated conical shape (trapezoidal shape to be flared toward the tip4ain a cross-sectional shape on a plane including the axis of the light guide4), and acts as a space portion communicating with the outside. Accordingly, the light emitted to an axially tilted portion within a recessed surface41awhich is a boundary surface between the light guide4having the recess41and the outside is condensed in the light emitting direction. The light guide4in the present embodiment is formed of a transparent resin material such as acrylic in a cylindrical shape of 9 mm in outer diameter and 24 mm in height. The recess41is in the circular truncated conical shape in which the diameter is 9 mm in the tip4aand the depth is 5 mm, and the diameter is 4 mm in the bottom surface (end portion inside the light guide4).

The cover5fixes the holding unit3and the light guide4, and is configured to include the first fixation unit51, the second fixation unit52and the opening53. The first fixation unit51is fixed to the holding unit3and is formed in a bottomed cylindrical shape. The first fixation unit51together with the holding unit3is adapted to close the light emitting unit2to be protected from the outside. The first fixation unit51internally communicates with the opening53. In the present embodiment, if the first fixation unit51is fixed to the main body32of the holding unit3, a portion of the light emitting unit2is left in a state of being inserted into the opening53. Accordingly, it is possible to prevent the light emitted from the light emitting unit2from being emitted to between the first fixation unit51and the holding unit3. The first fixation unit51is fixed to the holding unit3via a packing (not illustrated) configured to have an elastic material. That is, it is possible to prevent the outside atmosphere from entering through a portion fixed to the holding unit3of the cover5by using the packing. The first fixation unit51is fixed to the main body32so that the heat sink33is protruded outward further than the first fixation unit51. The second fixation unit52internally fixes the light guide4. The second fixation unit52has a cylindrical shape and internally has the opening53. Here, the outer diameter D2of the second fixation unit52is set to be smaller than the outer diameter D3of the first fixation unit51. It is preferable that the outer diameter D2of the second fixation unit52be as small as possible so as to approach the outer diameter D1of the light guide4, on the assumption that when the vehicle lighting device1A is attached to the lamp100by using the attachment unit6, the second fixation unit52sufficiently withstands the external force during the travelling of the vehicle and when the vehicle lighting device1A is attached to or detached from the lamp100. The second fixation unit52fixes the light guide4inserted into the opening53in a state of exposing the tip4a.

Here, a ratio D1/D2of the outer diameter D1of the light guide4to the outer diameter D2of the second fixation unit52has a relationship of 0.1≦D1/D2≦0.9. If the ratio D1/D2is less than 0.1, a proportion occupied by the light non-emitting region greatly causes design quality to be degraded. In contrast, if the ratio D1/D2is beyond 0.9, the strength of the attachment unit6is weakened, and thus damage occurs due to vibrations and shocks.

The attachment unit6is adapted to attach the vehicle lighting device1A to the lamp100which is the light emitting object. The attachment unit6is formed in the second fixation unit52and engages with the reception unit103. The attachment unit6of the present embodiment is configured so that a plurality of attachment units6is formed in the circumferential direction of the second fixation unit52. When the vehicle lighting device1A is attached to the lamp100by using the attachment unit6, the tip4aof the light guide4is first inserted into the insertion port104from the opposite side to the lens102side, and the second fixation unit52is inserted into the insertion port104until each attachment unit6opposes each reception unit103in the circumferential direction. Then, the vehicle lighting device1A is rotated around the axis of the lamp100, and each attachment unit6is inserted into each space portion103afrom the opening. Thus, each attachment unit6is engaged with each reception unit103. In this manner, the vehicle lighting device1A is attached to the lamp100in a state where the tip4aof the light guide4is exposed to the inside of the lamp100.

Next, an operation of the vehicle lighting device1A will be described. The vehicle lighting device1A is fixed to the lamp100as described above, and the power supply member is electrically connected to the external power source. If the power supply from the external power source is started, the power supplied from the external power source to the substrate22via the power supply member is supplied to each light emitting element21and each light emitting element21emits the light using the supplied power, thereby allowing the light emitting unit2to emit the light. The light emitted from the light emitting unit2is emitted to the light guide4from the end surface opposing to the light emitting unit2inside the opening53. The light guided into the light guide4is emitted into the lamp100from the tip4a, passes through the lens102from the inside of the lamp100, and is emitted outward, that is, is emitted outward from the vehicle.

Here, as illustrated inFIG. 3, in the light distribution characteristics of the light emitted from the vehicle lighting device1A, the light is emitted so as to be condensed from the vehicle lighting device1A, that is, from the tip4aof the light guide4toward the light emitting direction. In particular, the intensity of the light emitted toward the light emitting direction is adapted to be the strongest. Accordingly, the vehicle lighting device1A can obtain the light distribution characteristics having a directional strongpoint in the light emitting direction by forming the recess41in the light guide4. That is, if the recess41is formed in the light guide4, as compared to a case without forming the recess41, it is possible to adjust the directivity of the light, and thus it is possible to obtain desired light distribution characteristics.

As described above, in the vehicle lighting device1A according to the present embodiment, the outer diameter D2of the second fixation unit52to which the light guide4is fixed in a state of exposing the tip4ais smaller than the outer diameter D3of the first fixation unit51, and the vehicle lighting device1A is attached to the lamp100by using the attachment unit6formed in the second fixation unit52. Accordingly, it is possible to decrease the outer diameter of the attachment unit6, and it is possible to decrease the diameter of the insertion port104through which the vehicle lighting device1A of the lamp100is protruded. In addition, a portion exposed to the lamp100within the vehicle lighting device1A is the light guide4and the second fixation unit52. That is, it is possible to arrange the first fixation unit51so as not to be visible from the lamp100. Accordingly, when the vehicle lighting device1A is viewed from the front, it is possible to decrease the proportion occupied by the cover5which is the light non-emitting region with respect to the light guide4which is the light emitting region. In this manner, when the vehicle lighting device1A is viewed from the outside of the lamp100, it is possible to prevent the cover5from being noticeable, and it is possible to reduce the influence of the light non-emitting region on the design quality of the lamp100.

In addition, the second fixation unit52having the attachment unit6attached to the lamp100is a separate member from the light guide4. Accordingly, it is possible to change a fixing position of the light guide4with respect to the second fixation unit52in the axial direction. Therefore, it is possible to change the height of the tip4aof the light guide4with respect to the lamp100. As a result, it is possible to optionally change the light distribution characteristics of the vehicle lighting device1A with respect to the lamp100.

In addition, the light emitting unit2can be separated from the lamp100. Accordingly, it is possible to prevent the lamp100from being affected by thermal deformation, for example, due to the heat radiation from the vehicle lighting device1A. In addition, it is possible to prevent the heat from being radiated into the lamp100which is likely to accumulate the heat through the vehicle lighting device1A. Accordingly, it is possible to prevent the heat radiation performance from being degraded due to the attachment of the vehicle lighting device1A to the lamp100. In addition, as compared to a shape of the first fixation unit51which is determined by a shape of the substrate22or the like, a shape of the second fixation unit52has no limitation if the attachment unit6can be formed and the light guide4can be internally fixed. Accordingly, it is possible to optionally select a shape of the light non-emitting region, that is, a shape of the second fixation unit52when the vehicle lighting device1A is viewed from the outside of the lamp100. In this manner, it is possible to improve the design quality of the vehicle lighting device1A.

In the first embodiment described above, the recess41having the circular truncated conical shape has been described. However, the shape of the recess41is not limited thereto. The shape may be formed in a bottomed cylinder shape (for example, horizontal bottom surface), a conical shape, an elliptical conical shape or the like. In addition, in the recess41, an outer peripheral line in the cross-sectional shape may be either a straight line or a curve. In addition, an outer peripheral surface of the tip4aof the light guide4may be formed, for example, so as to be flared from the tip4aside to the light emitting unit2side, that is, may be formed in a tapered shape.

In addition, in the first embodiment described above, the recessed surface41aof the recess41may be formed to have a rough surface. For example, the recessed surface41ais formed to have the rough surface so that surface roughness Ra of the recessed surface41ais equal to or greater than 0.2. Accordingly, the light incident on the recessed surface41ais scattered and emitted outward from the recessed surface41asince the recessed surface41ais the rough surface. Therefore, it is possible to change the light distribution characteristics determined when the recessed surface41ais not formed to have the rough surface so as to be different light distribution characteristics. For example, it is possible to change the light distribution characteristics so as to have an incandescent bulb shape.

Second Embodiment

Next, a second embodiment will be described.FIG. 4illustrates a vehicle lighting device of the second embodiment.FIG. 5illustrates light distribution characteristics of the vehicle lighting device of the second embodiment. A vehicle lighting device1B illustrated inFIG. 4is different from the vehicle lighting device1A in that the reflection material42is in close contact with the recessed surface41aof the recess41.

The recess41of the light guide4has a conical shape. The recess41is filled with the reflection material42, thereby bringing the reflection material42into close contact with the recessed surface41a. For example, the reflection material42is a material in which the same material as the material forming the light guide4is used as a base material and reflection materials (white particles of titanium oxide, barium sulfate, calcium carbonate and the like) are included. A filling portion formed to have the reflection material42may be integrally molded with the light guide4or may be optically connected to the light guide4using a separate member. The reflection material42is configured so that the light incident on the reflection material42emitted from the light guide4is reflected into the light guide4. Accordingly, the light is prevented from being emitted outward of the light guide4from the reflection material42. The light guide4in the present embodiment is formed of the transparent resin material such as acrylic, in a cylindrical shape where the outer diameter is 9 mm and the height is 24 mm. The recess41is formed in a conical shape where the diameter in the tip4ais 9 mm and the depth is 5 mm.

Here, the light distribution characteristics of the light emitted from the vehicle lighting device1B are as follows. As illustrated inFIG. 5, the light is rarely emitted from the vehicle lighting device1B, that is, from the tip4aof the light guide4, in the light emitting direction. The light is mostly emitted from the outer periphery of the light guide4. In particular, the light is emitted diagonally further rearward (to the light emitting unit2side and radially outward of the light guide4) from the tip4aof the light guide4. Accordingly, in the vehicle lighting device1B, the recess41is filled with the reflection material42so that the reflection material42is brought into close contact with the recessed surface41a. Accordingly, it is possible to obtain the light distribution characteristics having a directional strongpoint in a sideway direction orthogonal to the light emitting direction or in a rearward direction opposite to the light emitting direction. That is, if the reflection material42is brought into contact with the recessed surface41aof the light guide4, as compared to a case of forming only the recess41, it is possible to adjust the directivity of the light, and thus it is possible to obtain desired light distribution characteristics.

In addition, in the second embodiment described above, the recess41is filled with the reflection material42, but the configuration is not limited thereto.FIG. 6illustrates a first modification example of the vehicle lighting device of the second embodiment.FIG. 7illustrates a second modification example of the vehicle lighting device of the second embodiment. For example, as illustrated inFIG. 6, a reflection material43may be brought into close contact with the recessed surface41aby bonding the reflection material43formed from a sheet-like member to the recessed surface41aof the recess41using a transparent adhesive. In addition, for example, as illustrated inFIG. 7, a reflection material44may be brought into close contact with the recessed surface41awithout filling the whole recess41by applying and drying the reflection material44having a liquid state or a paste state to the recessed surface41aof the recess41.

In addition, in the second embodiment described above, the reflection materials42to44are brought into close contact with the recessed surface41a, but a scattering material may be brought into close contact with the recessed surface41a. For example, the scattering material is a material in which the same material as the material forming the light guide4is used as a base material and scattering materials (scattering particles of titanium oxide, barium sulfate, calcium carbonate and the like) are included. If the scattering material is brought into close contact with the recessed surface41a, the light incident on the scattering material via the recessed surface41ais scattered and emitted outward from the recess41. Accordingly, it is possible to change the light distribution characteristics determined when the recessed surface41ais not formed to have the rough surface so as to be different light distribution characteristics.FIG. 8illustrates a third modification example of the vehicle lighting device of the second embodiment.FIG. 9illustrates a fourth modification example of the vehicle lighting device of the second embodiment. For example, as illustrated inFIG. 8, a scattering material45may be brought into close contact with the recessed surface41aby filling the circular truncated cone-shaped recess41with the scattering material45. In this case, it is possible to change the light distribution characteristics so as to have light distribution spreading all around the periphery. For example, as illustrated inFIG. 9, a scattering material46may be brought into close contact with the recessed surface41aby filling a bottomed cylindrical recess41with the scattering material46. In this case, it is possible to change the light distribution characteristics so as to have light distribution where the light is emitted while being diffused from the tip4aof the light guide4to the light emitting direction. The light guide4inFIG. 9is formed of the transparent resin material such as acrylic in a cylindrical shape of 9 mm in outer diameter and 24 mm in height. The recess41is formed in a cylindrical shape where the diameter in the tip4ais 2.5 mm and the depth is 5 mm.

Third Embodiment

Next, a third embodiment will be described.FIG. 10illustrates a vehicle lighting device of the third embodiment.FIG. 11illustrates light distribution characteristics of the vehicle lighting device of the third embodiment. A vehicle lighting device1C illustrated inFIG. 10is different from the vehicle lighting device1A in that the recess41is not formed in the light guide4.

The tip4aof the light guide4is formed in a plane. Accordingly, the light guided by the light guide4is emitted outward as it is without changing an optical path thereof. Accordingly, as illustrated inFIG. 11, in the light distribution characteristics of the light emitted from the vehicle lighting device1C, the light is emitted while being diffused from the vehicle lighting device1C, that is from the tip4aof the light guide4to the light emitting direction. However, in particular, intensity of the light in the light emitting direction is lower than intensity of the light around the light emitting direction.

The vehicle lighting device1C can be applied not only to a case where the light is directly emitted to the lamp100for example, but also to a case where the light is emitted via a lamp side light guide plate (not illustrated) for example. When the light is indirectly emitted to the lamp100, it is preferable that the light distribution characteristics of the vehicle lighting device1C be similar to the light distribution characteristics of the light emitted from the optically connected lamp side light guide plate. Accordingly, without changing the light distribution characteristics of the light emitted from the light guide4having the same function as the lamp side light guide plate, the light is emitted to the lamp side light guide plate as it is. In this manner, if those which are different from the expected light distribution characteristics (light distribution characteristics of the vehicle lighting device1C) are applied thereto as are in the light distribution characteristics of the vehicle lighting devices1A and1B, it is possible to prevent the light distribution characteristics of the light emitted from the lamp side light guide plate from being different from desired light distribution characteristics.

In addition, the light guide4of the first to third embodiments described above is formed in a cylindrical shape. The light guide4is formed so as to have a range of dimensions where the outer diameter is 5 mm to 20 mm, the height of a portion protruding from the cover5is 0 mm to 50 mm, and the height of a portion inserted into the opening53is 1 mm to 30 mm. In addition, when the recess41is formed in the light guide4, the light guide4is formed in a circular truncated conical shape, a conical shape or a cylindrical shape. The light guide4is formed so as to have a range of dimensions where the diameter in the tip4ais 2 mm to 19 mm (not exceeding the outer diameter of the light guide4), the depth is 1 mm to 40 mm (not exceeding the height of the light guide4), and the diameter in the bottom surface (end portion inside the light guide4) is 0 mm to 19 mm (not exceeding the outer diameter of the light guide4).

Fourth Embodiment

A fourth embodiment will be described with reference toFIGS. 12 to 14.FIG. 12is a partial cross-sectional view of a vehicle lighting device of the fourth embodiment.FIG. 13is a plan view illustrating a light guide of the vehicle lighting device of the fourth embodiment.FIG. 14is a plan view illustrating a cover of the vehicle lighting device of the fourth embodiment.FIG. 12(FIGS. 15,17to20are also the same) mainly illustrates the light guide4and the cover5in a cross-sectional shape on a plane including the axial direction. In the fourth embodiment, a case will be described where each lighting element21of the light emitting unit2is not sealed with the resin and the holding unit3has no mount31.

The light guide4is configured to include a light guide fixation portion47aand a light emitting unit inserting recess48.

The light guide fixation portion47ais to be fixed to the cover5, and is formed to protrude in the radial direction of the light guide4in a substantially center portion in the axial direction, that is, in the vertical direction of a vehicle lighting device1D. In the present embodiment, as illustrated inFIG. 13, two light guide fixation portions47aare formed with equal intervals in the circumferential direction. Here, within the light guide4, the tip4aside from the light guide fixation portion47ais referred to as a tip side portion4band the light emitting unit2side is referred to as a light emitting unit side portion4c. The tip side portion4band the light emitting unit side portion4chave a cylindrical shape, and are formed so that an outer diameter D12of the tip side portion4bis larger than an outer diameter D11of the light emitting unit side portion4c. In addition, an outer diameter D13of the light guide fixation portion47a(twice the distance between the center axis of the light guide4and the outer peripheral surface which is farthest from the center axis within the light guide fixation portion47a) is formed to be the largest outer diameter of the light guide4. That is, the outer diameter D11of the light emitting unit side portion4c, the outer diameter D12of the tip side portion4band the outer diameter D13of the light guide fixation portion47ahave a relationship of D11<D12<D13. Accordingly, the outer diameter D12from the light guide fixation portion47ato the tip4aside is larger than the outer diameter D11from the light guide fixation portion47ato the light emitting unit2side. In addition, the outer diameter D12of the tip side portion4bis set so that between the light beams (L1and L2illustrated inFIG. 12) guided from the light emitting unit2to the light guide4, the light beam (L1) passing through a boundary between the light guide fixation portion47aand the light emitting unit side portion4cis not incident on a surface of the tip4aside of the light guide fixation portion47a.

The light emitting unit inserting recess48is formed on an end surface (lower surface) of the light emitting unit2side, and the light emitting unit2is inserted. Since the light emitting unit2is surrounded by the light emitting unit inserting recess48, it is possible to prevent the light emitted from the light emitting unit2in the horizontal direction of the light emitting unit2from leaking out from the light guide4. The light guide4is in contact with or is optically connected to the light emitting unit2with a slight gap. That is, the light emitted from the light emitting unit2is incident through the end surface of the light emitting unit2side of the light guide4, is totally reflected inside the light guide4and is emitted outward from the tip4a, that is, the end surface (upper surface) of the tip4aside in the present embodiment.

A space S is formed between the cover5and the holding unit3. The light emitting unit2is accommodated in the space S and is not exposed outward.

The opening53is formed in a center portion on an upper surface5aof the cover5, and the light guide4is inserted. In the present embodiment, the light guide4is inserted from the upper surface5aside. A portion of the light guide4, that is, the light emitting unit side portion4cand the light guide fixation portion47aare accommodated in the space S. Here, if the light guide fixation portion47ais fixed to the cover5in a state where the light guide4is inserted into the opening53a, the tip4ais exposed from the opening53. The opening53has a notched portion53a. Two notched portions53aare formed to protrude in the radial direction of the opening53with equal intervals in the circumferential direction so as to enable each light guide fixation portion47ato be inserted as illustrated inFIG. 14in the present embodiment. The diameter of the opening53is set so that when the light guide4is fixed to the cover5, the outer peripheral surface of the light guide4and the cover5are in contact with each other in the horizontal direction, or oppose each other with a gap. When preventing leakage of the light guided by the light guide4from the boundary between the light guide4and the cover5to the cover5side, it is preferable to form a gap between the outer peripheral surface of the light guide4and the cover5in the opening53, that is, it is preferable to cause the outer peripheral surface of the light guide4and the cover5to oppose each other so as not to be in contact with each other.

As illustrated inFIG. 12, the positioning portion54opposes the light guide4in the radial direction of the light guide4, and is formed in the space S. In the present embodiment, the positioning portion54is arranged in a substantially center portion of the space S in the vertical direction of the vehicle lighting device1D inFIG. 12. In addition, as illustrated inFIG. 14, the positioning portion54is formed to protrude toward a center O of the cover5in a substantially fan shape. Two positioning portions54are formed to oppose each other in the radial direction of the light guide4. In a state where the light guide4is inserted into the opening53, the positioning portion54opposes the light emitting unit2side from the light guide fixation portion47awithin the light guide4, that is, the light emitting unit side portion4c, in the radial direction of the light guide4. A positioning space portion55formed between two positioning portions54is set so that a width D4including the center O of the cover5is slightly larger than the outer diameter of the light guide4, here, the outer diameter D11of the light emitting unit side portion4c. That is, it is prevented that the light guide4is fixed to the cover5in a state where each positioning portion54is in contact with the light guide4. Accordingly, it is possible to prevent the light guided by the light guide4from leaking out from the boundary between the light guide4and the cover5to the cover5side by bringing the outer peripheral surface of the light guide4into contact with the cover5.

Next, assembly of the vehicle lighting device1D will be described. As illustrated inFIG. 12, the holding unit3is first caused to hold the light emitting unit2in advance. Then, in a state where the light guide fixation portion47aand the notched portion53aoppose each other in the vertical direction of the vehicle lighting device1D inFIG. 12, the light guide4is inserted into the opening53of the cover5. At this time, the light emitting unit side portion4cpasses through the positioning space portion55. Then, if the light guide fixation portion47ais positioned in the inner side (space S) of the cover5via the notched portion53a, in a state where the light guide4is inserted into the opening53, the light guide fixation portion47ais fixed to the cover5by being rotated around the axis of the cover5. In this manner, the light guide fixation portion47acomes into contact with and is fixed to the cover5in the space S side of the upper surface5awithin the cover5, that is, in the inner side of the cover5. Then, the holding unit3is inserted into and fixed to the cover5to which the light guide4is fixed. At this time, the light emitting unit2is inserted into the light emitting unit inserting recess48of the positioned light guide4in the radial direction of the light guide4by using the positioning portion54and in the axial direction of the light guide4by using the light guide fixation portion47a. Accordingly, when the light guide4is inserted into the cover5, it is possible to perform positioning of the light guide4in the axial direction by using the positioning portion54. In addition, it is possible to reliably perform the positioning of the light guide4in the axial direction by bringing the light guide fixation portion47aprotruding in the radial direction of the light guide4into contact with the space S side of the upper surface5a. In this manner, the positioning of the light guide4in the axial direction and the radial direction is performed in advance. Therefore, it is possible to prevent the light guide4from coming into contact with the light emitting unit2even when the cover5is fixed to the holding unit3. Furthermore, an attachment unit (not illustrated) allows the vehicle lighting device1D to be attached to the lamp in a state of exposing the tip4aof the light guide4into the lamp.

Next, an operation of the vehicle lighting device1D will be described. The vehicle lighting device1D is attached to a lamp as described above, and a power supply member is electrically connected to an external power source. If power supply from the external power source is started, the power supplied from the external power source to the substrate22via the power supply member is supplied to each light emitting element21and each light emitting element21emits the light using the supplied power, thereby allowing the light emitting unit2to emit the light. The light beams (L1and L2illustrated inFIG. 12) emitted from the light emitting unit2are incident on the light guide4from the light emitting unit inserting recess48. The light guided into the light guide4is emitted into the lamp from the tip4a, passes through a lens (not illustrated) from the inside of the lamp, and is emitted outward, that is, is emitted outward from a vehicle.

Here, when the light guide4is used, it is necessary to fix the light guide4to the cover5in which the light emitting element21is accommodated. For example, a method may be considered in which a flange-shaped fixation portion is formed in the light emitting element21side of the light guide4opposing the light emitting element21, the fixation portion is inserted into a reception portion formed inside the cover5, and an opposite side to the light emitting element21side is brought into close contact with and is fixed to the cover5from the fixation portion within the light guide4. In this case, there is a possibility that the light emitted from the light emitting element21and guided by the light guide4may leak out to the cover5side in the boundary between the light guide4and the cover5, thereby causing a problem in that a light-extraction efficiency of the light emitted from the light guide4is degraded.

As described above, in a state where the light guide4is inserted to the opening53of the cover5, the vehicle lighting device1D according to the present embodiment is fixed to the cover5by using the light guide fixation portion47a. Thus, it is possible to reduce a contact area between the light guide4and the cover5. Accordingly, the light guide4can mostly come into contact with the space S, that is, an air layer. Therefore, by bringing the outer peripheral surface of the light guide4into contact with the cover5, it is possible to prevent the light guided by the light guide4from leaking out from the boundary between the light guide4and the cover5to the cover5side.

In addition, the light guide4is fixed to the cover5by using the light guide fixation portion47a, and the outer diameter D12of the tip side portion4bis larger than the outer diameter D11of the light emitting unit side portion4c. Thus, it is possible to prevent an increase in the frequency of refraction until the light emitted from the light emitting unit2and guided by the light guide4is reflected on a surface of the tip4aside of the light guide fixation portion47aand is guided to the tip4a. Accordingly, it is possible to prevent the optical path from being lengthened, and it is possible to decrease the light emitted outward from the light guide fixation portion47a. In this manner, by fixing the light guide4to the cover5, it is possible to prevent the light-extraction efficiency of the light emitted from the light guide4from being degraded.

In the fourth embodiment described above, the positioning portion54is disposed in the cover5, but the embodiments described herein are not limited thereto.FIG. 15is a partial cross-sectional view illustrating a modification example of the vehicle lighting device of the fourth embodiment.FIG. 16is a plan view illustrating a cover in the modification example of the vehicle lighting device of the fourth embodiment. As illustrated inFIG. 15, the cover5of a vehicle lighting device1E may not include the positioning portion54illustrated inFIG. 12. In this case, in a state where the light guide fixation portion47aand opening53oppose each other in the vertical direction of the vehicle lighting device1E inFIG. 15, the light guide4can be inserted into the opening53from the space S side. Accordingly, as illustrated inFIG. 16, the cover5may not include the notched portion53aillustrated inFIG. 14.

In the fourth embodiment described above, the shape of the light guide4is the cylindrical shape, but the embodiment is not limited thereto.FIG. 17is a partial cross-sectional view illustrating a first modification example of the vehicle lighting device of the fourth embodiment.FIG. 18is a partial cross-sectional view illustrating a second modification example of the vehicle lighting device of the fourth embodiment.FIG. 19is a partial cross-sectional view illustrating a third modification example of the vehicle lighting device of the fourth embodiment. The outer diameter D12of the tip side portion4bmay not be constant from an end portion of the light emitting unit2side to the tip4a. As illustrated inFIG. 17, a vehicle lighting device1F may be configured so that a portion from the light emitting unit2side of the tip side portion4bto a portion exposed from the cover5is set to be a constant outer diameter D12, an outer diameter of the tip4aside is more decreased than the outer diameter D12, and the tip4ais allowed to have an outer diameter D14which is smaller than the outer diameter D12. In addition, as illustrated inFIG. 18, a vehicle lighting device1G may be configured so that an outer diameter from an end portion of the light emitting unit2side of the tip side portion4bto the tip4ais increased and the tip4ais allowed to have an outer diameter D16which is larger than the outer diameter D12of the end portion of the light emitting unit2side. That is, the outer diameter D12of the end portion of the light emitting unit2side of the tip side portion4bis larger than the outer diameter D11of the light emitting unit side portion4c, the light distribution characteristics may be changed by changing the shape of the tip4aand changing the optical path of the guided light beams (L3and L4illustrated inFIG. 17, L5and L6illustrated inFIG. 18). As illustrated inFIG. 18, the light guide fixation portion47bmay be formed so as to surround the tip side portion4b(the outer diameter D13of the end portion of the light emitting unit2side of the fixation unit43is the same as the outer diameter D12of the end portion of the light emitting unit2side of the tip side portion4b). That is, the tip side portion4bmay be caused to function as the light guide fixation portion47b. In this case, similar to a fifth embodiment (to be described later), the light guide fixation portion47bis fixed to an outer side of the cover5.

In addition, as illustrated inFIG. 19, a vehicle lighting device1H may be configured so that the recess41is formed in the tip4aas in the vehicle lighting device1A of the first embodiment described above. The recess41may be formed in a conical shape, an elliptical cone shape, a bottomed cylinder shape (for example, horizontal bottom surface), a circular truncated conical shape (trapezoidal shape to be flared toward the tip4ain a cross-sectional shape on a plane including the axis of the light guide4). The recess41may be configured so that the outer peripheral line in a cross-sectional shape may be either a straight line or a curve. In addition, the recessed surface of the recess41may be formed to have a rough surface. For example, the recessed surface is formed to have the rough surface so that surface roughness Ra of the recessed surface is equal to or greater than 0.2. Accordingly, the light incident on the recessed surface is scattered and emitted outward from the recessed surface since the recessed surface is the rough surface. Therefore, it is possible to change the light distribution characteristics determined when the recessed surface is not formed to have the rough surface so as to be different light distribution characteristics. For example, it is possible to change the light distribution characteristics so as to have an incandescent bulb shape. The reflection material or the scattering material may be brought into close contact with the recessed surface of the recess41. For example, the reflection material is a material in which the same material as the material forming the light guide4is used as a base material and reflection materials (white particles) are included. By reflecting the light incident on the reflection material from the light guide4into the light guide4, it is possible to prevent the light from being emitted outward from the light guide4from the reflection material. For example, the scattering material is a material in which the same material as the material forming the light guide4is used as a base material and scattering materials (scattering powder) are included. The light incident on the scattering material via the recessed surface is scattered and emitted outward from the recess41. Accordingly, it is possible to change the light distribution characteristics determined when the recessed surface41ais not formed to have the rough surface so as to be different light distribution characteristics. That is, by changing the shape of the tip4a, it is possible to change the light distribution characteristics of the vehicle lighting device1H to be desired light distribution characteristics.

Fifth Embodiment

Next, a fifth embodiment will be described.FIG. 20is a partial cross-sectional view illustrating a vehicle lighting device of the fifth embodiment.FIG. 21is a plan view illustrating the vehicle lighting device of the fifth embodiment. A vehicle lighting device1I illustrated inFIG. 20is different from the vehicle lighting device1D in that a light guide fixation portion47cis fixed to the outer side of the cover5.

The light guide4has the tip side portion4bof the tip4aside from the light guide fixation portion47cand the light emitting unit side portion4cof the light emitting unit side from the light guide fixation portion47c, two portions of which have a different outer diameter. The tip side portion4bis positioned in an outer portion side which is the opposite side to the space S side of the upper surface5aof the cover5. The light emitting unit side portion4cis positioned in the space S of the upper surface5a. The tip side portion4band the light emitting unit side portion4chave a cylindrical shape. The outer diameter D12of a portion excluding the light guide fixation portion47cof the tip side portion4bis the same as the outer diameter D11of the light emitting unit side portion4c. The light guide fixation portion47cis formed in the tip side portion4b. In the present embodiment, the light guide fixation portion47cis formed to protrude in the radial direction of the light guide4in the tip side portion4b. As illustrated inFIG. 21, two light guide fixation portions47care formed in the circumferential direction with equal intervals. In addition, the outer diameter D13of the light guide fixation portion47d(twice the distance between the center axis of the light guide4and the outer peripheral surface which is farthest from the center axis within the light guide fixation portion47a) is formed to be the largest outer diameter of the light guide4. That is, the outer diameters D11to D13have a relationship of D11(=D12)<D13. The outer diameter D12of the tip4aside from the light guide fixation portion47cis the same as the outer diameter D11of the light emitting unit2side from the light guide fixation portion47c. The outer diameter D13of the light guide fixation portion47cis larger than the outer diameter D12of the tip4aside from the light guide fixation portion47c. Here, in the present embodiment, the light guide fixation portion47cis formed to extend to the tip4a. However, the height from the upper surface5aof the cover5may be lower than the height of the tip side portion4b.

When assembling the vehicle lighting device1I, if the light guide4is inserted into the opening53of the cover5, the light emitting unit side portion4cis caused to pass through the positioning space portion54and the light guide fixation portion47cis brought into contact with the upper surface5aof the cover5. In this state, the light guide fixation portion47cis fixed to the cover5. In this manner, the light guide fixation portion47cis brought into contact with and fixed to the outer portion side of the upper surface5awithin the cover5, that is, the outer side of the cover5. It is possible to reliably perform the positioning of the light guide4in the axial direction by bringing the light guide fixation portion47cprotruding in the radial direction of the light guide4into contact with outer portion side of the upper surface5a.

As described above, the vehicle lighting device1I according to the present embodiment demonstrates an effect which is the same as that of the fourth embodiment described above. It is possible to perform the positioning of the light guide4with respect to the cover5simply by inserting the light guide4into the opening53of the cover5. Accordingly, it is possible to improve efficiency of the assembly work. Here, the fifth embodiment can employ the modification examples illustrated inFIGS. 17 to 19.

In the fourth and fifth embodiments and the first to third modification examples of the fourth embodiment, when the light guide fixation portions47ato47care brought into contact with the upper surface5aof the cover5, a recess into which the light guide fixation portions47ato47care inserted may be formed on the upper surface5ain advance. In the fourth and fifth embodiments and the first to third modification examples of the fourth embodiment, without forming the light emitting unit inserting recess48in the light guide4, similar to the first to third embodiments, the end portion of the light emitting unit2side of the light guide4may be arranged to oppose the light emitting unit2.

The fixing method of the light guide4with respect to the cover5in the above-described embodiments (including all embodiments and all modification examples) is not particularly limited. Any fixing method such as mechanical fixing by using engagement members and fastening members or chemical fixing by using an adhesive may be used.

In addition, in the above-described embodiments, the cover5to which the light guide4is fixed may be attachable to and detachable from the holding unit3. In this case, the light guide4and the cover5are unitized together in advance by fixing the light guide4which is different in a type corresponding to each embodiment (modification example) to the cover5in advance. In contrast, the light emitting unit2is held by the holding unit3to be unitized together in advance. Then, a unit of the light guide4and the cover5which satisfies the light distribution characteristics is selected for the vehicle lighting device required according to the lamp to be attached, and the selected unit is mounted on the unit of the light emitting unit2and the holding unit3. In this manner, the unit of the light guide4and the cover5is selected and replaced with respect to the unit of the light emitting unit2and the holding unit3. Therefore, it is possible to provide a vehicle lighting device having desired light distribution characteristics.

In addition, in the above-described embodiments, the substrate22functions as the mounting substrate and the driving substrate, but may be used separate from the mounting substrate and the driving substrate. In this case, the driving substrate does not need to focus on heat transfer, since components generating a lot of heat such as each light emitting element21are not mounted thereon. Therefore, it is possible to provide an insulating substrate formed of inexpensive materials such as paper phenol, paper epoxy, glass epoxy and the like.

As described above, according to the above-described embodiments, it is possible to decrease the proportion occupied by the light non-emitting region with respect to the light emitting region when viewed from the front.

In addition, according to the above-described embodiments, by fixing the light guide4to the cover5, it is possible to prevent the light-extraction efficiency of the light emitted from the light guide4from being degraded.