Light emitting device

A light emitting device includes a light emitter, a holding portion that slidably holds the light emitter inside a slide rail for a vehicle, and a light transmissive cover that covers the light emitter. According to a configuration, the cover of the light emitting device prevents a decrease in a communication performance of a signal transmission and reception device in which information on an electronic device is transmitted using an LED, as compared with a related art in which the communication performance decreases due to influence of scattering or shielding a light of the LED, the influence being caused by a grease which is heavily applied inside a slide rail of a vehicle and adheres to the LED.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-092375 filed on May 15, 2019, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a light emitting device which is provided inside a slide rail for vehicle.

BACKGROUND ART

In the related art, a signal transmission and reception device described in JP2013-067322A has been proposed as the light emitting device described above. According to the signal transmission and reception device described above, an LED (light emitter) is attached to a lower surface of a slide seat, and to an upper rail slidably attached to a slide rail. Information on an electronic device such as a seating sensor provided in the slide seat is transmitted using the LED.

However, according to the light emitting device described above, the LED slides inside the slide rail in which a large amount of grease is applied. Therefore, the grease in the slide rail may adhere to the LED, and communication performance may decrease due to influence of scattering, shielding, or the like of light which is caused by the grease.

SUMMARY OF INVENTION

The present disclosure is to provide a light emitting device capable of preventing a decrease in the communication performance.

According to a first illustrative aspect of the present disclosure, a light emitting device includes a light emitter, a holding portion that slidably holds the light emitter inside a slide rail for a vehicle, and a light transmissive cover that covers the light emitter.

According to a second illustrative aspect of the present disclosure, the cover has a tubular shape, an opening is formed in the cover, and a direction in which the opening extends is an irradiation direction in which a light is emitted from the light emitter.

According to a third illustrative aspect of the present disclosure, the cover has a bottomed tubular shape, and a bottom portion covering the light emitter is formed in the cover at a position to face the light emitter in an irradiation direction of the light emitter, the irradiation direction being a direction in which the light emitter emits a light towards the bottom portion.

According to a fourth illustrative aspect of the present disclosure, the bottom portion of the cover has a shape that a protrusion amount protruding towards an irradiation direction increases as the bottom portion approaches a central axis of the light emitter on which the light of the light emitter becomes strongest.

According to the first illustrative aspect, since the cover is provided, influence of the grease can be reduced, and a decrease in communication performance can be prevented.

According to the second illustrative aspect, since the cover is provided in a tubular shape and is open on the irradiation direction side of the light emitter, the influence of the grease adhered to the cover can be reduced, and the decrease in the communication performance can be prevented.

According to the third illustrative aspect, the cover is provided in a bottomed tubular shape and has a bottom portion that covers the irradiation direction side of the light emitter. The grease is less likely to be applied over the entire bottom portion since the bottom portion of the cover is larger than the light emitter, and the decrease in the communication performance can be prevented.

According to the fourth illustrative aspect, the bottom portion of the cover is provided in such a shape that the protrusion amount in the irradiation direction increases as the bottom portion approaches the central axis along which the strongest light of the light emitter is emitted. Therefore, the grease is less likely to adhere to a portion of the cover which intersects the central axis, and the decrease in the communication performance can be prevented.

According to the present disclosure, it is possible to provide a light emitting device capable of reducing influence of grease and preventing a decrease in communication performance.

The present disclosure is briefly described as above. Further, details of the present disclosure will be clarified by reading a mode for carrying out the present disclosure (hereinafter, referred to as “embodiments”) described below with reference to the accompanying drawings.

DESCRIPTION OF EMBODIMENTS

As illustrated inFIG. 1, a communication system1includes a light emitting device2of the present disclosure and a light receiving device3. The communication system1of the present embodiment is an optical communication system for transmitting information on an electronic device (a seating switch SW1and a buckle switch SW2in the present embodiment) mounted on a vehicle slide seat10to an electronic device (a meter ECU50in the present embodiment) provided on a vehicle body side.

The slide seat10mainly includes a seat cushion11and a seat back12. With an upper rail20that is attached to a lower surface of the seat cushion11, and with a slide rail30that is disposed below the seat cushion11and to which the upper rail20is slidably attached, the slide seat10is slidable along a longitudinal direction D1of the slide rail30.

In the present embodiment, the slide seat10is provided with the seating switch SW1, the buckle switch SW2, and a battery40.

The seating switch SW1is one of electronic devices mounted on the slide seat10. The seating switch SW1is, for example, disposed in the seat cushion11, is pressed to be turned ON when an occupant sits on the slide seat10, and is turned OFF when the occupant gets out of the slide seat10.

The buckle switch SW2is one of the electronic devices mounted on the slide seat10. The buckle switch SW2is provided in a buckle of a seat belt, is turned OFF when a tongue is inserted into the buckle of the seat belt, and is turned ON when the tongue is pulled out.

As illustrated inFIG. 2, the battery40supplies power to a light emitting diode (hereinafter referred to as “LED”)4serving as a light emitter of the light emitting device2, which will be described below, via the seating switch SW1and the buckle switch SW2that are connected in series.

The upper rail20is obtained by subjecting a metal plate to roll forming, pressing, welding, and the like. As illustrated inFIG. 3, the upper rail20is positioned outside the slide rail30, and includes a seat attachment portion21to which the slide seat10is attached, and a slide portion22positioned inside the slide rail30.

Next, the slide rail30will be described before describing details of the upper rail20. The slide rail30is formed in an elongated tubular shape with a metal plate, and a slit31extending in the longitudinal direction D1is formed in an upper surface thereof. The seat attachment portion21of the upper rail20protrudes from the slit31to the outside of the slide rail30.

The slide rail30has a bottom wall32provided in an elongated shape in the longitudinal direction D1, a pair of side walls33, a pair of upper walls34, and a pair of inner walls35. The bottom wall32overlaps with a floor panel70of an automobile. The pair of side walls33is erected from both ends in a width direction D2of the bottom wall32. The pair of upper walls34extends in directions to approach each other from upper ends of the pair of side walls33. The pair of inner walls35sags from end portions, of the pair of upper walls34, separated from the side walls33. The slide rail30is formed to have the same cross-sectional shape from one end all along to the other end in the longitudinal direction D1.

Grease is applied to an upper surface of the bottom wall32, inner side surfaces in the width direction D2of the pair of side walls33, lower surfaces of the pair of upper walls34, and outer side surfaces in the width direction D2of the pair of inner walls, all of which define an inside of the slide rail30, so that the upper rail20is easy to slide. The slit31refers to a space between the pair of inner walls35.

A mat80is disposed above the floor panel70, and the upper wall34of the slide rail30is exposed from a slit81provided in the mat80. A pair of moors90is attached to the pair of upper walls34of the slide rail30. The pair of moors90covers the slit31to prevent foreign matters from entering the slide rail30. An attachment body212, which will be described below, of the seat attachment portion21of the upper rail20passes between the pair of moors90and protrudes from below the moors90to above the moors90.

Next, details of the upper rail20will be described. The seat attachment portion21includes a pair of outer side walls211and the attachment body212. The pair of outer side walls211is arranged side by side in the width direction D2between the pair of inner walls35, that is, in the slit31. The attachment body212is bent in a substantially rectangular tube shape and is connected to upper ends of the pair of outer side walls211. As illustrated inFIG. 1, the attachment body212is provided to be shorter than the pair of outer side walls211in the longitudinal direction D1; the pair of outer side walls211, and the slide portion22to be described below, protrude more than the attachment body212at one end side in the longitudinal direction D1.

As illustrated inFIG. 3, the slide portion22has a pair of bottom walls221that are provided in an elongated shape in the longitudinal direction D1and a pair of inner side walls222. The pair of bottom walls221is arranged on a lower side of lower ends of the pair of inner walls35, and the pair of outer side walls211is erected from end portions thereof on an inner side in the width direction D2. The pair of inner side walls222is erected from an outer side in the width direction D2of the bottom walls221and is arranged inside the slide rail30. Wheels223running on the bottom wall32of the slide rail30are attached on an outer side in the width direction D2of the inner side walls222.

As illustrated inFIGS. 3 and 4, the light emitting device2includes an LED4, a substrate5on which the LED4is mounted, a holding portion6that slidably holds the substrate5inside the slide rail30, and a light transmissive cover7that covers the LED4. As illustrated inFIG. 2, the LED4is connected to the battery40via the seating switch SW1and the buckle switch SW2. Accordingly, when an occupant is seated and the seat belt is not worn, both the seating switch SW1and the buckle switch SW2are turned on, power is supplied from the battery40to the LED4, and the LED4emits light. The LED4is held by the holding portion6, which will be described below, such that an irradiation direction D3thereof is along the longitudinal direction D1of the slide rail30.

The substrate5is provided in a substantially rectangular shape as viewed from the top, and is disposed inside the slide rail30to be perpendicular to the longitudinal direction D1.

The holding portion6is formed of a synthetic resin. As illustrated inFIG. 4, the holding portion6includes a holding body61that holds the substrate5, and a pair of locking arms62that are locked to one of the pair of inner side walls222. The holding body61is attached to the substrate5so as to cover a side opposite to the LED4of the substrate5.

The pair of locking arms62protrude from the holding body61toward a side opposite to the irradiation direction D3, and a pair of locking claws62A protruding in an upper-lower direction D4are provided at tip ends of the pair of locking arms62. One of the pair of inner side walls222(one on the right side in the example illustrated inFIG. 3) is provided with cutouts222A for locking the locking claws62A of the locking arms62. The cutouts222A are provided at an upper end and a lower end of the inner side wall222, respectively. The pair of locking arms62is provided side by side in the upper-lower direction D4. One of the locking claws62A protruding toward a lower side is provided at the tip end of the locking arm62on an upper side, and the other locking claw62A protruding toward an upper side is provided at the tip end of the locking arm62on a lower side.

When the inner side wall222is vertically sandwiched between the pair of locking arms62, the locking arm62on the upper side is locked to the cutout222A provided at the upper end of the inner side wall222. Further, the locking arm62on the lower side is locked to the cutout222A provided at the lower end of the inner side wall222.

Accordingly, as illustrated inFIG. 3, the holding portion6is accommodated in a space surrounded by the inner wall35, the upper wall34, the side wall33, and the bottom wall32which are on the right side of the slide rail30. The substrate5of the holding portion6is disposed on one end side in the longitudinal direction D1of the slide portion22(inner side wall222) of the upper rail20.

By locking the holding portion6to the upper rail20as described above, the holding portion6slides in conjunction with sliding of the upper rail20and of the slide seat10. The LED4is held by the holding portion6as described above, and is disposed inside the slide rail30.

The cover7is formed of a light transmissive member such as glass or acrylic. As illustrated inFIGS. 4 and 5, the cover7is provided in a rectangular tube shape and is open on an irradiation direction D3side of the LED4. In the present embodiment, the cover7is also open on a side opposite to the irradiation direction D3side. More specifically, the cover7includes a large rectangular tube portion71provided on the side opposite to the irradiation direction D3side, and a small rectangular tube portion72that is smaller than the large rectangular tube portion71and that is provided on the irradiation direction D3side. Holes73of the large rectangular tube portion71and the small rectangular tube portion72have the same size. The LED4is entirely accommodated inside the cover7.

The light receiving device3has a photodiode (not illustrated). As illustrated inFIG. 1, the light receiving device3is introduced inside the slide rail30from an opening at one end in the longitudinal direction D1of the slide rail30and is fixed to one end portion thereof. Accordingly, the LED4of the light emitting device2and the photodiode of the light receiving device3can be disposed to face each other in the longitudinal direction D1. The photodiode detects light emitted from the LED4, and notifies the meter ECU50that the occupant is seated and the seat belt is not worn. In a case where the light receiving device3detects light emitted from the LED4when an ignition is turned on and a vehicle speed is, for example, equal to or greater than 3 km/h, the meter ECU50determines that the occupant is not wearing the seat belt, and displays that as a warning on an indicator60.

According to the embodiment described above, by providing the cover7that covers the LED4, the influence of the grease can be reduced, and the decrease in the communication performance can be prevented.

According to the embodiment described above, the cover7is provided in a tubular shape and is open on the irradiation direction D3side of the LED4. For this reason, since the cover7is not provided on the irradiation direction D3side of the LED4, the influence of the grease adhered to the cover7can be reduced, and the decrease in the communication performance can be prevented.

The present disclosure is not limited to the embodiment described above and may be appropriately modified, improved, or the like. In addition, the material, shape, size, number, arrangement position and the like of each component in the embodiment described above are optional and are not limited as long as the present disclosure can be achieved.

That is, according to the embodiment described above, the cover7is formed in a tubular shape and is open on the irradiation direction D3side of the LED4, and the present disclosure is not limited thereto. As illustrated inFIGS. 6 and 7, the cover7may be provided in a bottomed tubular shape and have a bottom portion74that covers the irradiation direction D3side of the LED4, and the bottom portion74of the cover7may be provided in such a shape that a protrusion amount in the irradiation direction D3increases as it approaches a central axis Z along which the strongest light of the LED4is emitted. As illustrated inFIG. 7, in the present embodiment, the bottom portion74is provided in a quadrangular pyramid shape.

By providing the cover in such a shape, grease is less likely to adhere to a portion of the bottom portion74of the cover7which intersects the central axis Z, and a decrease in communication performance can be prevented. With respect to the shape of the bottom portion74, the grease is less likely to adhere to the apex as an apex that intersects the central axis Z gets sharper, and the decrease in the communication performance can be further prevented.

Further, according to the embodiment illustrated inFIG. 7, the bottom portion74of the cover7is provided in such a shape that the protrusion amount in the irradiation direction D3increases as it approaches a central axis Z along which the strongest light of the LED4is emitted, and the present disclosure is not limited thereto. The bottom portion74may be provided to be flat. When the grease adheres to the entire bottom portion74of the cover7, the communication performance rapidly drops. However, even if the bottom portion74of the cover7is flat as described above, it is almost impossible that the grease adheres to the entire bottom portion74since the bottom portion74of the cover7is larger than the LED4. Therefore, even in a case where the bottom portion74is provided to be flat, a decrease in communication performance can be prevented as compared with a case where the cover7is not provided.

Further, according to the embodiment described above, the holding portion6is locked to the upper rail20by the locking arm62, and the present disclosure is not limited thereto. The holding portion6may be fixed to the upper rail20by a bolt, a nut, or the like.

Further, according to the embodiment described above, the LED4is connected to the battery40via the seating switch SW1and via the buckle switch SW2, and the present disclosure is not limited thereto. For example, a control unit of the LED4such as a microcomputer may be provided on the substrate5, and the control unit may control light emission of the LED4according to states of the seating switch SW1and the buckle switch SW2.

Illustrative aspects according to the present disclosure is described hereinafter.

According to an illustrative aspect of the present disclosure, a light emitting device (2) includes a light emitter (4), a holding portion (6) that slidably holds the light emitter (4) inside a slide rail (30) for a vehicle, and a light transmissive cover (7) that covers the light emitter (4).

According to another illustrative aspect of the present disclosure, the cover (7) has a tubular shape, an opening is formed in the cover, and a direction in which the opening extends is an irradiation direction (D3) in which a light is emitted from the light emitter (4).

According to another illustrative aspect of the present disclosure, the cover (7) has a bottomed tubular shape, and a bottom portion (74) covering the light emitter (4) is formed in the cover (7) at a position to face the light emitter (4) in an irradiation direction (D3) of the light emitter (4), the irradiation direction (D3) being a direction in which the light emitter (4) emits a light towards the bottom portion (74).

According to another illustrative aspect of the present disclosure, the bottom portion (74) of the cover (7) has a shape that a protrusion amount protruding towards an irradiation direction (D3) increases as the bottom portion (74) approaches a central axis (Z) of the light emitter (4) on which the light of the light emitter (4) becomes strongest.

According to another illustrative aspect of the present disclosure, the bottom portion (74) includes a plurality of outer surfaces, and the plurality of outer surfaces intersect with each other at a sharp angle.

According to another illustrative aspect of the present disclosure, the tubular shape of the cover (7) is a rectangular tubular shape. The cover (7) includes a large rectangular tube portion (71) and a small rectangular tube portion (72) that is smaller than the large rectangular tube portion (71), along the irradiation direction (D3) of the light emitter (4).

According to another illustrative aspect of the present disclosure, the opening of the cover (7) is a through hole (73) extending in the irradiation direction (D3). The through hole (73) penetrates the large rectangular tube portion (71) and the small rectangular tube portion (72), in the irradiation direction (D3). A dimension of the through hole (73) in the large rectangular tube portion (71) and a dimension of the through hole (73) in the small rectangular tube portion (72) are same.

According to another illustrative aspect of the present disclosure, the holding portion (6) includes a pair of locking arms (62) which protrudes towards an opposite direction to the irradiation direction of the light emitter (4), and a locking claw (62A) which is respectively provided at tip ends of the pair of locking arms (62), the pair of locking arms (62) being flexible. The locking claw (62A) is configured such that the pair of locking arms (62) are locked to the slide rail (30).