Vehicle interior lighting system

A vehicle interior lighting system includes: a designed cover 10 attached to a ceiling wall in an inside of a vehicle compartment; and a light source unit 20 arranged in the rear of the designed cover. In this system, a light beam emitted from an emission port 25 of the light source unit illuminates the inside of the vehicle compartment through two irradiation holes 15 for spot illumination, which are provided in the designed cover. A light guide 50 is arranged between the emission port 25 of the light source unit and the two irradiation holes 15 of the designed cover. The light guide 50 is configured to divide the light beam emitted from the light source unit into two directions, and to guide the thus-divided light beams to the respective irradiation holes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle interior lighting system which is installed in the ceiling of a vehicle compartment.

2. Description of the Related Art

FIG. 1shows a conventional example of the vehicle interior lighting system which is installed in the ceiling of the compartment (see Japanese Patent Application Laid-Open No. 2003-175765).

This vehicle interior lighting system200includes: a main illuminator210configured to illuminate a wide area in the compartment; two spot illuminators220each configured to illuminate a narrow area in the compartment; and a switch230, which are provided to a designed cover201attached to the ceiling wall of a vehicle. The main illuminator210is provided with multiple LEDs211functioning as a light source and an outer lens212. Each spot illuminator220is provided with an LED (not illustrated) and an outer lens222.

In the conventional vehicle interior lighting system200, each of the illuminators210,220and220is equipped with at least one LED. This increases the number of parts, thus causing weight and cost increase. Furthermore, the two spot illuminators220tend to exhibit unevenness in color and illuminance even if two LEDs with the same color are used for the two spot illuminators220, because the two LEDs vary from each other. This may cause difference in appearance among illuminated areas depending on which LED to be used.

SUMMARY OF THE INVENTION

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a vehicle interior lighting system which makes it possible to reduce weight and cost, and to be easily assembled by reducing the number of light sources, as well as to reduce unevenness in color and illuminance by sharing a single light source among multiple illuminators.

To achieve the object, according to a first aspect of the present invention, there is provided a vehicle interior lighting system includes: a designed cover attached to a ceiling wall in the inside of a vehicle compartment; and a light source unit arranged in the rear of the designed cover. In this configuration, a light beam emitted from an emission port of the light source unit illuminates the inside of the compartment through multiple illuminators provided in the designed cover. Moreover, a light guide is arranged between the emission port of the light source unit and the multiple illuminators in the designed cover, the light guide being configured to divide the light beam emitted from the emission port of the light source unit into multiple light beams which travel in different directions, and thereby to guide the light beams thus divided to the respective multiple illuminators.

The first aspect of the present invention makes it possible to make the number of light source units smaller than the number of illuminators provided in the designed cover, since the light beam from the light source unit is divided into the multiple light beams and thereby the multiple light beams are guided to the multiple illuminators. This makes it possible to guide the light beam from the single light source unit to the two illuminators, for example. Consequently, the reduction in the number of light source units enables weight and cost reduction. Concurrently, the reduction in the number of wirings enables this system to be easily assembled. Furthermore, since the light from the common light source unit is guided to the multiple illuminators, unevenness in color and illuminance of the light beams can be reduced, which would otherwise lo occur due to variations among light source units themselves.

A second aspect of the present invention is the vehicle interior lighting system according to the first aspect thereof, in which: as the multiple illuminators, the designed cover is provided with multiple irradiation holes for spot illumination, through which small areas away from each other are respectively illuminated; the light source unit is arranged in a location away from the multiple irradiation holes by almost the same distance; the light guide includes a light incident surface, a light dividing unit, arms and light emitting surfaces. The light incident surface is configured so that the light beam emitted from the emission port of the light source unit is incident thereon. The light dividing unit is configured to divide the light beam incident on the light incident surface into the multiple light beams which travel in the different directions. The number of the different directions corresponds to the number of the irradiation holes. The arms are configured to guide the light beams divided by the light dividing unit to the irradiation holes, respectively. The light emitting surfaces are provided on the respective end portions of the arms so as to correspond to the irradiation holes, and thereby configured to emit the light beams having come to the light emitting surfaces through the arms to the irradiation holes, respectively.

The second aspect of the present invention makes it easy to perform control such that the amounts of light beams through the multiple illuminators can be equal to one another, since the light source unit is arranged in the location away from the multiple illuminators by almost the same distance.

A third aspect of the present invention is the vehicle interior lighting system according to the first or the second aspect thereof, in which: as the multiple illuminators, the designed cover is provided with multiple irradiation holes for spot illumination, through which small areas away from each other are respectively illuminated; the light source unit is arranged in a location opposed to one irradiation hole among the multiple irradiation holes; and the light guide includes a light incident surface, a light dividing unit, a first light emitting surface, arms, and second light emitting surfaces. The light incident surface is configured so that the light beam emitted from the emission port of the light source unit is incident thereon. The light dividing unit is configured to divide the light beam incident on the light incident surface into the multiple light beams which travel in the different directions. The number of the different directions corresponds to the number of the irradiation holes. The first light emitting surface is configured to emit one light beam toward the one irradiation hole located opposed to the light source unit. The one light beam is one of the light beams having been divided by the light dividing unit and thus traveling in one direction. The arms are configured to respectively guide the other light beams toward the other irradiation holes. The other light beams are the other of the light beams which have been divided by the light dividing unit and thus traveling in the other directions, respectively. The second light emitting surfaces are provided on the respective end portions of the arms so as to correspond to the other irradiation holes, and thereby configured to emit the light beams having come to the second light emitting surfaces through the arms toward the other irradiation holes, respectively.

The third aspect of the present invention makes it possible to guide the light from the single light source unit to the illuminators at desired positions, and to cause the light beams to illuminate the inside of the vehicle compartment through the illuminators, respectively, by setting appropriately the number, directions and lengths of the arms. That is because the light source unit is arranged in the location opposed to one of the multiple illuminators, and because the rest of illuminators receive the light beams through the arms of the light guide, respectively.

A fourth aspect of the present invention is the vehicle interior lighting system according to any one aspect among the first aspect to the third aspect thereof, in which: as the multiple of illuminators, the designed cover is provided with an irradiation hole for spot illumination, through which a small area is illuminated, and a surface-shaped illuminator ( a flat-surface-shaped illuminator) configured to emit light in a shape of a plane; the light source unit is arranged in a location opposed to the irradiation hole for spot illumination; and the light guide includes a light incident surface, a light dividing unit, a first light emitting surface, an arm, and a second light emitting surface. The light incident surface is configured so that the light beam emitted from the emission port of the light source unit is incident thereon. The light dividing unit is configured to divide the light beam incident on the light incident surface into two light beams. The first light emitting surface is configured to emit one of the two light beams having divided by the light dividing unit toward the irradiation hole. The arm is configured to guide the other of the two light beams having divided by the light dividing unit toward the surface-shaped illuminator. The second light emitting surface is provided in the arm so as to correspond to the surface-shaped illuminator, and thereby configured to emit the light beam having come to the second light emitting surface toward the surface-shaped illuminator in the shape of a plane.

In a case where, for example, a designed unit formed of optical transparent resin is illuminated from its rear by surface light emission, the fourth aspect of the present invention needs no light source unit for the designed unit besides the light source unit for spot illumination, thus reducing the number of light source units, and thereby enabling size reduction. That is because the light beam from the light source unit is divided into a light beam for the spot illumination and a light beam for a surface-shaped illuminator (a light beam for the illumination by surface light emission).

A fifth aspect of the present invention is the vehicle interior lighting system including: a designed cover attached to a ceiling wall in an inside of a vehicle compartment; and a light source unit arranged in a rear of the designed cover. In this configuration, a light beam emitted from an emission port of the light source unit illuminates the inside of the vehicle compartment through a single illuminator provided in the designed cover; and a prism-shaped light guide is arranged between the emission port of the light source unit and the single illuminator in the designed cover. The light guide is configured to divide the light beam from the emission port of the light source unit into multiple light beams which travel in different directions, and thus to emit the light beams thus divided in the different directions through the single illuminator.

In a case where spot light beams illuminate different directions, the fifth aspect of the present invention makes it possible to reduce the number of light source units. That is because the provision of the prism-shaped light guide allows the light to illuminate the different directions through the single illuminator. Accordingly, the reduction in the number of light source units enables weight and cost reduction. Concurrently, the reduction of the number of wirings enables this system to be easily assembled, as well as enables size and space reduction. Moreover, since the light from the common light source unit is guided to the multiple illuminators, unevenness in color and illuminance of the light beams can be reduced, which would otherwise occur due to variations among light source units themselves.

A sixth aspect of the present invention is the vehicle interior lighting system according to any one aspect among the first aspect to the fifth aspect, in which: as a light source, an LED is provided in the light source unit; and a fluorescent agent for changing a hue of light from the LED is contained in the light guide.

The sixth aspect of the present invention enables cost reduction, since use of a fluorescent agent contained in the light guide enables the blue light from a low-cost blue LED, for example, to be changed into white light.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Descriptions will be provided hereinafter for embodiments of the present invention by referring to drawings.

Referring now toFIGS. 2 to 10, a first embodiment according to the present invention will be explained hereinbelow.

As shown inFIGS. 2 and 3, a vehicle interior lighting system1includes: a housing2located in the rear of this system; a functional unit5located in the rear thereof; a cover3for a sunglass holder; a lens cover4for a main illuminator; and a designed cover10for spot illuminators. The housing2and the functional unit5are embedded in a ceiling in the inside of a vehicle compartment. The cover3, the lens cover4and the designed cover10are coverings located in the front of this system.

The designed cover10for the spot illuminators is capable of being attached to and detached from the housing2. As shown inFIGS. 4 and 5, a light guide50and a light source unit20are fitted to the rear of the designed cover10.

Two spot irradiation holes (illuminators)15for a map lamp and a switch12are provided in a center portion of the designed cover10. The spot irradiation holes (hereinafter simply referred to as “irradiation holes”) are located away from each other, and penetrate the center portion of the designed cover10. A designed unit11for the switch12is provided in a vicinity of the switch12. The irradiation holes15are transparent holes for spot illumination, through which to illuminate small areas away from each other, respectively. In the designed unit11, a character part with optical transparency is configured to shine when the designed unit11is illuminated from its rear (from the inside of the designed cover10).

As shown inFIGS. 6A and 6B, the light source unit20includes an LED (not illustrated) in the inside of a light-shielding case21as a light source. With one-touch operation, the light source unit20is configured to be fixed to a predetermined location by causing engaged parts (for example, claws)22provided on the sides of the case21to be engaged with engaging parts (for example, engagement holes)17of a light source unit attaching unit16provided in the rear of the designed cover10. The light source unit20includes, in its front, an emission port25through which a light beam from the LED goes out to the outside. In this embodiment, the light source unit attaching unit16is arranged in a location which is away from the irradiation holes15by almost the same distance, i.e., in the middle between the two irradiation holes15.

The light guide50is provided between the emission port25of the light source unit20and the two irradiation holes15of the designed cover10, and is configured to divide a light emitted from the emission port25into two directions, and thus to guide the resultant two light beams to the corresponding irradiation holes15. The light guide15is made of transparent resin such as acryl or polycarbonate.

As shown inFIGS. 7A and 7B, the light guide50is provided with a light incident surface51, a light dividing unit52, left and right arms53, light emitting surfaces55, and holed brackets58. The light incident surface51is configured to receive the incident light emitted from the emission port25of the light source unit20. The light dividing unit52is configured to divide the light incident on the light incident surface51into multiple directions (two directions in this case) whose number corresponds to the number of irradiation holes15. The left and right arms53are configured to guide the resultant multiple light beams divided by the light dividing unit52to the respective irradiation holes15. The light emitting surfaces55are provided on the respective end portions of the arms53so as to correspond to the irradiation holes15, whereby the light beams having traveled through the arms53are caused to go out toward the irradiation holes15from the light emitting surfaces55, respectively. The brackets58are configured to attach the light guide50to the designed cover10.

As attaching units18to attach the light guide50to the designed cover10, bosses18awith ribs18bare provided to the designed cover10. As shown inFIG. 9B, the light guide50is fixed to the designed cover10through the following process. First, the bosses18aare fitted into the holes of the brackets58, respectively. Then, the brackets58are caused to abut on the abutment surfaces of the ribs18b,respectively. Subsequently, the end portions of the bosses18aare melted, whereby the brackets58are welded to the respective attaching units18. The light guide50may be fixed to the designed cover10with screws instead of by welding.

Furthermore, as shown inFIG. 8, the light source unit20is attached and fixed to the light source unit attaching unit16of the designed cover10by putting the light source unit20over the light guide50thus fixed. Thereby, as shown inFIG. 9A, the emission port25of the light source unit20and the light incident surface51of the light guide50are positioned to each other in a non-contact manner with an appropriate space in between. Simultaneously, as shown inFIG. 9B, the light emitting surfaces55of the light guide50and the irradiation holes15of the designed cover10are positioned to each other in a non-contact manner with an appropriate space in between.

Note that, in consideration of the dimensional tolerance and the like, the light incident surface51of the light guide50is larger than the emission port25of the light source unit20, and each light emitting surface55of the light guide50is larger than each irradiation hole15.

With the configuration described above, as shown by hollow arrows inFIG. 10, the light beam from the light source unit20is divided into the two directions by the light dividing unit52of the light guide50. Then, the resultant two light beams are guided to the two irradiation holes15through the left and right arms53, respectively. Thereby, two spotlight beams S can illuminate predetermined areas in the inside of the compartment from the irradiation holes15, respectively.

In this case, light is supplied to the two irradiation holes15in the designed cover10from the single light source unit20. Thereby, the number of light source units20can be reduced, thus resulting in weight and cost reduction. Additionally, since the number of wirings is reduced, this system can be assembled more easily. Furthermore, since the light beam from the common light source unit20is guided to the two irradiation holes15so as to illuminate the irradiation holes serving as the spotlight beams, it is possible to reduce unevenness in color and illuminance of the illuminated light beams, which would otherwise occur due to product variations of LEDs themselves serving as light sources. Moreover, in the case of the vehicle interior lighting system according to this embodiment, the light source unit20is arranged in the location which is away from the two irradiation holes15by almost the same distance. This makes it easy to perform control such that the amounts of light beams emitted through the two irradiation holes15can be equal to each other.

Descriptions will be provided hereinbelow for a second embodiment by referring toFIGS. 11 to 15.

As shown inFIGS. 11 and 12, a light guide60and a light source unit20are attached to the rear of a designed cover10B for spot illuminators. Two spot irradiation holes (illuminators, hereinafter “irradiation holes”)15for a map lamp are provided to the designed cover10B. The two irradiation holes15are located away from each other, and penetrate the designed cover10B. A light source unit attaching unit16is provided to one side of the rear of the designed cover10B so that the light source unit20can be attached so as to face one of the two irradiation holes15. The configuration of the light source unit20and attaching means thereof are the same as those of the first embodiment. Thus, the same components lo will be denoted by the same reference numerals, and descriptions thereof will be omitted.

The light guide60is configured to divide a light beam emitted from an emission port25of the light source unit20into two directions, and thus to guide the resultant two light beams to the respective irradiation holes15. The light guide60is made of transparent resin such as acryl or polycarbonate. As shown inFIGS. 13A and 13B, the light guide60is provided with a light incident surface61, a light dividing unit62, a first light emitting surface65A, an arm63, a second light emitting surface65B, and holed brackets68. The light incident surface61is configured to receive the incident light emitted from the emission port25of the light source unit20. The light dividing unit62is configured to divide the light beam incident on the light incident surface61into two directions. The first light emitting surface65A is configured to emit one light beam toward a first irradiation hole15located opposed to the light source unit20. This light beam is one of the light beams having divided by the light dividing unit62and thus travels in a first direction. The arm63is configured to guide the other light beam to a second irradiation hole15located away from the first irradiation hole15. This light beam is the other of the light beams having divided by the light dividing unit62and thus travels in the other direction. The second light emitting surface65B is provided on the end portion of the arm63so as to correspond to the second irradiation hole15. Thereby, the light beam having traveled through the arm63is caused to go out toward the second irradiation hole15from the second light emitting surface65B. The brackets68are configured to attach the light guide60to the designed cover10B.

As attaching units18to attach the light guide60to the designed cover10B, bosses18awith ribs18bare provided to the designed cover10B, similar to the first embodiment. Thus, the light guide60is fixed to the designed cover10B through the following process. First, the bosses18aare fitted into the holes of the brackets68, respectively. Then, the brackets68are caused to abut on the abutment surfaces of the ribs18b, respectively. Subsequently, the end portions of the bosses18aare melted. Thereby, the brackets68are welded to the respective attaching units18. Thereafter, as shown inFIG. 14, the light source unit20is attached and fixed to a light source unit attaching unit16of the designed cover10B by putting the light source unit20over the light guide60. Thereby, an emission port25of the light source unit20and the light incident surface61of the light guide60are positioned to each other in a non-contact manner. Simultaneously, light emitting surfaces65A and65B of the light guide60and the irradiation holes15of the designed cover10B are positioned to each other in a non-contact manner. In this case, the light guide60may be attached to the designed cover10B with screws as well.

According to this embodiment, the light source unit20is arranged in the location opposed to one of the two irradiation holes15, and one light beam is guided to the other irradiation hole15through the arm63of the light guide60. Thus, a light beam from the single light source unit20can be guided to the irradiation holes15located in desired positions by setting the direction and length of the arm63appropriately. Accordingly, as shown by the two hollow arrows inFIG. 15, the two spotlight beams S from the respective irradiation holes15in the designed cover10B can illuminate predetermined areas in the inside of the compartment. Thereby, the number of light source units20can be reduced, thus resulting in weight and cost reduction. Additionally, the reduction in the number of wirings makes it easier for this system to be assembled. Moreover, since one light beam from the common light source unit20is guided to the multiple irradiation holes15so as to illuminate the irradiation holes serving as the spotlight beams, it is possible to reduce unevenness in color and illuminance of the illuminated light beams, which would otherwise occur due to product variations of LEDs themselves as light sources.

Descriptions will be provided hereinbelow for a third embodiment by referring toFIGS. 16 to 18.

As multiple illuminators, a designed cover10C includes: an irradiation hole15for spot illumination, through which a small area is illuminated; and a designed unit11which functions as a surface-shaped illuminator (a flat-surface-shaped illuminator), and is configured to emit light in the shape of a plane (of two dimensions). In the designed unit11, a character part with optical transparency is configured to shine when the designed unit11is illuminated from its rear (from the inside of the designed cover10C).

A light source unit20is arranged in a location opposed to the irradiation hole15for spot illumination. A light guide80is provided with a light incident surface81, a light dividing unit82, a first light emitting surface85, an arm83and a second light emitting surface86. The light incident surface81is configured to receive a light beam emitted from an emission port25of the light source unit20. The light dividing unit82is configured to divide the light beam incident on the light incident surface81lo into two light beams. The first light emitting surface85is configured to emit one of the two light beams having divided by the light dividing unit82toward the irradiation hole15. The arm83is configured to guide the other light beam to the designed unit11which is the surface-shaped illuminator. The second light emitting surface86is provided to the arm83so as to correspond to the designed unit11, and thus is configured to emit the light beam having traveled through the arm83to the designed unit11in the shape of a plane.

The designed cover10C is provided with an attaching unit (not illustrated) for attaching the light guide80. When the light guide80is attached to the attaching unit, the first light emitting surface85of the light guide80is positioned to a location corresponding to the irradiation hole15of the designed cover10C, and the second light emitting surface86is positioned to a location corresponding to the designed unit11of the designed cover10C. Thereafter, when the light source unit20is attached and fixed to a light source unit attaching unit16of the designed cover10C, the emission port25of the light source unit20and the light incident surface81of the light guide80are positioned to each other. The rest of the configuration is the same as that of each of the first and second embodiments. Thus, the same components are denoted by the same reference numerals, and descriptions thereof will be omitted.

According to this embodiment, one light beam from the single light source unit20is supplied to the irradiation hole15for spot illumination and the luminescent designed unit11. This makes it unnecessary to prepare another light source unit for the designed unit11in addition to that for the spot illumination. This makes it possible to reduce the number of light source units20, and thereby to reduce the weight and costs. Additionally, the reduction in the number of wirings makes it easier for this system to be assembled. Moreover, since one light beam from the common light source unit20is guided to the two illuminators (the irradiation hole15and the designed unit11) so as to illuminate the two illuminators, it is possible to reduce unevenness in color and illuminance of the illuminated light beams, which would otherwise occur due to product variations of LEDs themselves as light sources. Particularly, this embodiment enables the predetermined design of the designed cover10C to be caused to emit light. Thus, the designed unit11can be illuminated at night without adding a light source for the designed illumination, even in the designed unit11which is desired to be always lit but is difficult to be provided with a light source.

Descriptions will be provided hereinbelow for a fourth embodiment by referring toFIGS. 19 to 21.

A designed cover10D according to this embodiment is provided with only a single irradiation hole15for spot illumination in its center portion. A light guide70is shaped like a prism as shown inFIG. 20, and includes: two flat-surface-shaped light incident surfaces71, which form an angle, in its rear; and a curved light emitting surface75in its front. The light guide70is configured to divide a light beam S incident on the light incident surfaces71in its rear from the light source unit20to two directions, and thus to emit the resultant two light beams diagonally through the single irradiation hole15in different directions. The rest of the configuration of the light source unit20and the like is the same as that of the first embodiment.

Since the prism-shaped light guide70is provided in this embodiment, the spotlight beams S can illuminate the different directions through the single irradiation hole15provided in the designed cover10D. This makes it possible to reduce the number of light source units20, and accordingly to reduce the weight and costs. Further, the reduction in the number of wirings enables this system to be easily assembled, and to save the space.

Moreover, because one light beam from the common light source unit20is divided into the two spotlight beams S by the prism-shaped light guide70, it is possible to reduce unevenness in color and illuminance of the illuminated light beams, which would otherwise occur due to product variations of LEDs themselves as light sources of the light source unit20.

Note that, for example, when a low-cost blue LED is used, if a fluorescent agent for changing the hue of light from the light source unit20is contained in the light guides50,60,70and80in the above embodiments, blue light can be changed into white light by the fluorescent agent contained in the light guides50,60,70and80. This makes it possible to reduce the costs.

The first, the second and the third embodiments show the case where at least one of two types of illuminators (the irradiation hole15and designed unit11) is provided in each of the designed covers10,10B and10C so that the light beam from the light source unit20can be divided by each of the light guides50,60and80into the two directions. Instead, the light beam may be divided by each of the light guides50,60and80into three or more directions so that the light beam can be supplied to three or more illuminators. Similarly, in the fourth embodiment, the light beam from the light source20may be divided into three or more directions.

The entire contents of Japanese Patent Application P2007-323218 (filed on Dec. 14, 2007) are incorporated herein by reference.