Lamp unit and method for manufacturing lamp unit

A lamp unit according to an embodiment is a lamp unit that irradiates with light from a light source, and includes: a circuit board on which the light source is mounted; a housing configured to have an internal space for accommodating the circuit board; a lens configured to be attached to the housing and emit the light from the light source to the outside of the housing, wherein the housing include an insertion hole for inserting the circuit board into the internal space from the outside of the housing to which the lens is attached.

TECHNICAL FIELD

The present disclosure relates to a lamp unit and a method for manufacturing the lamp unit.

BACKGROUND

Conventionally, various lamp units have been known. Japanese Unexamined Patent Publication No. 2012-192879 describes a lamp unit that is fixed by being attached to a back surface of a reflection mirror. The reflection mirror has a light transmitting portion that transmits light and a light non-transmitting portion that reflects the light. The light transmitting portion is formed of transparent glass, and the light not-transmitting portion is formed by depositing a reflective film on a back surface of the transparent glass. The light transmitting portion is formed by peeling the reflective film from the transparent glass by a blast treatment.

The lamp unit includes a circuit board to which a first LED and a second LED are fixed, a lamp housing having an opening for accommodating the circuit board, and a plate-shaped light diffusing portion that is attached to a periphery of the opening of the lamp housing and seals the opening of the lamp housing that accommodates the circuit board. The light diffusing portion is attached to a reflective film provided on a back surface of the reflection mirror via a cushion tape. The light from the first LED and the second LED is emitted to the outside of the reflection mirror through the light diffusing portion and the light transmitting portion of the reflection mirror.

In the lamp unit, the circuit board in which the first LED and the second LED are fixed is accommodated inside the lamp housing. A power supply to the first LED and the second LED is performed from a feeding wiring extending from the lamp housing. The feeding wiring is electrically connected to the first LED and the second LED by passing a connector provided at a tip of the feeding wiring through a notch formed in the lamp housing and inserting the connector into a connector receiving portion of the circuit board.

SUMMARY

In the lamp unit described above, after the circuit board to which the feeding wiring and the connector are connected is accommodated in the lamp housing, the light diffusing portion is fixed to the lamp housing by welding. Since heat and vibration are applied to the welding of the light diffusing portion to the lamp housing, the heat and vibration applied to the circuit board may cause solder cracks or damage to electronic components on the circuit board. In addition, local heat applied to the circuit board may cause deformation of the circuit board due to residual stress.

In addition, annealing treatment may be performed to suppress the deformation of the circuit board due to the residual stress. In the annealing treatment, the lamp housing accommodating the circuit board and the light diffusing portion are heated for a certain period of time. Even when the annealing treatment is performed, the heat is applied to the circuit board, so that the solder cracks and the like may still occur on the circuit board. Therefore, there is room for improvement in terms of the quality of the lamp unit. Further, in the annealing treatment, since the lamp housing is put into a furnace together with the feeding wiring, the number of lamp units that can be put into the furnace is limited. Therefore, there is room for improvement in terms of manufacturing efficiency.

It is an object of the present disclosure to provide a lamp unit and a method for manufacturing the lamp unit capable of improving quality and being efficiently manufactured.

A lamp unit according to one aspect of the present disclosure is a lamp unit that irradiates with light from a light source, and includes: a circuit board on which the light source is mounted; a housing configured to have an internal space for accommodating the circuit board; a lens configured to be attached to the housing and emit the light from the light source to the outside of the housing, in which the housing includes an insertion hole for inserting the circuit board into the internal space from the outside of the housing to which the lens is attached.

The lamp unit has the housing in which the internal space for accommodating the circuit board on which the light source is mounted is formed, and the housing has the insertion hole for inserting the circuit board into the internal space from the outside of the housing to which the lens is attached. Therefore, in the lamp unit, since the lens can be attached to the housing before the circuit board is inserted into the insertion hole, heat and vibration can be prevented from being applied to the circuit board. Therefore, since it is possible to prevent solder cracks from occurring in the circuit board and damage to electronic components mounted on the circuit board, the quality of the lamp unit can be improved. In addition, when the lamp unit is subjected to an annealing treatment, only the lens and the housing can be annealed before the circuit board is inserted, so that the number of lamp units that can be placed in a furnace can be increased. Therefore, since more lamp units can be manufactured by one annealing treatment, the lamp unit can be manufactured efficiently.

The circuit board may have an engaging portion that engages with the housing in the internal space, and the housing may have an engaged portion on which the engaging portion is caught in the internal space. In this case, the engaging portion of the circuit board inserted into the internal space of the housing via the insertion hole engages with the engaged portion of the housing. Therefore, since the circuit board can be inserted from the insertion hole and the engaging portion can be easily engaged with the engaged portion of the housing, the lamp unit can be easily assembled. Therefore, the lamp unit can be manufactured more efficiently.

The lamp unit includes a feeding harness configured to extend from the circuit board; and a tubular grommet configured to have a hole where the circuit board and the harness are inserted, in which the grommet seals the insertion hole in a state in which the circuit board is inserted into the internal space. In this case, the grommet seals the insertion hole of the housing in a state in which the circuit board is accommodated in the internal space of the housing. Therefore, when the grommet seals the insertion hole, it is possible to suppress an intrusion of water or the like into the internal space of the housing, so that a waterproof effect can be exhibited. In addition, by pushing the grommet into the insertion hole in the state in which the circuit board is inserted into the internal space, since the grommet can be mounted at the same time as the circuit board is mounted, the lamp unit can be easily assembled.

A method for manufacturing a lamp unit according to one aspect of the present disclosure is a method for manufacturing a lamp unit that irradiates with light from a light source, and includes: a process of attaching a lens that emits the light from the light source to the outside of a housing to the housing of the lamp unit; and a process of inserting a circuit board on which the light source is mounted into an internal space of the housing from the outside of the housing through an insertion hole formed in the housing after the lens is attached to the housing.

In the method for manufacturing the lamp unit, the lens is preliminarily attached to the housing of the lamp unit in the process of attaching the lens. After that, the circuit board on which the light source is mounted is inserted from the outside through the insertion hole into the internal space of the housing to which the lens is preliminarily attached. Therefore, since the lens is attached to the housing before the circuit board is inserted into the insertion hole, heat and vibration cannot be applied to the circuit board when the lens is attached to the housing. As a result, as in the case of the lamp unit described above, since damage to the circuit board is avoided, the quality of the lamp unit can be improved. In addition, since only the housing and the lens can be annealed when the lens is attached to the housing, the number of lamp units to be put in a furnace at the time of an annealing treatment can be increased. Therefore, since more lamp units can be manufactured by one annealing treatment, the manufacturing can be efficiently performed.

According to the present disclosure, the quality can be improved and the manufacturing can be efficiently performed.

DETAILED DESCRIPTION

Hereinafter, embodiments of a lamp unit according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and a duplicated description will be omitted as appropriate. In addition, the drawings are partially simplified or exaggerated for easy understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

A lamp unit1according to the present embodiment constitutes a BSM unit as an example. The BSM unit constituted by the lamp unit1is attached to, for example, an outer mirror provided on a vehicle body of a vehicle. As a specific example, the BSM unit constituted by the lamp unit1is a mirror-mounted BSM, but may be a visor side surface BSM provided on a side surface of a visor of the outer mirror facing a vehicle body side. In this case, for example, the BSM unit including the lamp unit1can be visually recognized by a driver sitting in a driver's seat, and the lamp unit1can be illuminated to alert the driver when another vehicle approaches.

FIG. 1is a perspective view illustrating the lamp unit1according to the present embodiment.FIG. 2is an exploded perspective view of the lamp unit1. The lamp unit1includes a light source11, a circuit board12on which the light source11is mounted, a housing13having an internal space13bfor accommodating the light source11and the circuit board12, a lens14that emits light from the light source11to the outside of the housing13, and a grommet15that seals the internal space13b.

The lamp unit1irradiates with the light from the light source11. The light source11is, for example, an LED light source. The circuit board12has, for example, a plate shape having a long side12bextending in a first direction D1and a short side12cextending in a second direction D2intersecting the first direction D1. The circuit board12has a plate shape that extends to be long in the first direction D1, and has a thickness in a third direction D3that intersects both the first direction D1and the second direction D2.

The housing13has an insertion hole13cinto which the circuit board12is inserted. The insertion hole13ccommunicates with the internal space13bof the housing13. The insertion hole13cis a hole through which the circuit board12is passed when the circuit board12is accommodated in the internal space13bof the housing13. The insertion hole13cis a hole into which the circuit board12is inserted into the internal space13bfrom the outside of the housing13to which the lens14is attached. Therefore, the maximum value of an interval of the insertion hole13cin the second direction D2is larger than the maximum value of a length of the circuit board12in the second direction D2. In the present embodiment, the above-mentioned “interval” indicates a width of the space in which the circuit board12enters.

The light source11is mounted on one side of the circuit board12in the first direction D1. On the other side of the circuit board12in the first direction D1, a connector portion16and a receptacle portion17that accommodates the connector portion16are mounted. A feeding harness18electrically connected to the light source11via the circuit board12extends from the connector portion16. The grommet15has a small hole15bthrough which the harness18is inserted, and the harness18extends from the small hole15bof the grommet15to the outside of the lamp unit1along the first direction D1.

The housing13has a box-shaped portion13din which the internal space13bis formed, and a tubular portion13fthat protrudes from the box-shaped portion13din the first direction D1and has an insertion hole13cformed inside. The box-shaped portion13dhas a box shape extending in both the first direction D1and the third direction D3and having a thickness in the second direction D2.

The tubular portion13fprotrudes from one side (left side inFIGS. 1 and 2) of the third direction D3on a side surface13gof the box-shaped portion13dfacing the first direction D1. The lens14is attached to the box-shaped portion13dof the housing13. The box-shaped portion13dhas a frame-shaped opening13hextending in both the first direction D1and the third direction D3and facing the second direction D2, and the internal space13band the opening13hare sealed by the lens14. The lens14functions as, for example, a transparent cover.

FIG. 3is a perspective view illustrating the lens14. As illustrated inFIG. 3, the lens14exhibits a plate shape extending in both the first direction D1and the third direction D3. The lens14emits the light from the light source11to the outside of the lamp unit1. For example, the lens14has an exposure surface14bexposed to the outside of the lamp unit1. The exposure surface14bis exposed to the side surface of the visor of the outer mirror, as an example. For example, the exposure surface14bincludes a first exposure surface14cextending in both the first direction D1and the third direction D3, and a second exposure surface14drecessed in the second direction D2in the first exposure surface14c.

The lens14has a convex portion14fprotruding in the second direction D2on an opposite side (lower side inFIG. 3) of the second exposure surface14d. For example, a protruding height of the convex portion14fdecreases from one side (left side inFIG. 3) to the other side (right side inFIG. 3) of the third direction D3. Therefore, a top surface of the convex portion14fis inclined with respect to a plane extending in both the first direction D1and the third direction D3.

For example, a lens cut14gis formed on at least one of the top surface of the convex portion14fand the second exposure surface14d. As an example, the lens cut14gincludes a plurality of unevennesses arranged along the third direction D3, and each of the plurality of unevennesses extends in an arc shape. However, the shape and arrangement of the lens cut14gare not limited to the above examples and can be changed as appropriate.

Since the second exposure surface14dof the lens14corresponds to an emitting portion from which the light emitted from the light source11is emitted, and the lens14includes the lens cut14g, the diffused light diffused by the lens cut14gis output from the second exposure surface14d. In this way, since the diffused light is emitted from the lamp unit1by the lens cut14g, the lamp unit1can be easily and visually recognized.

FIG. 4is a perspective view illustrating the circuit board12on which the light source11is mounted, the grommet15, and the harness18. As illustrated inFIG. 4, the grommet15has a hole portion15cwhere a portion of the circuit board12and the harness18are inserted, and the hole portion15ccommunicates with the small hole15bdescribed above. A width of the hole portion15cis, for example, about the same as a width of an end portion of the circuit board12in the first direction D1. Therefore, it is possible to fit the circuit board12into the hole portion15c.

The grommet15has an annular convex portion15dextending in the second direction D2and the third direction D3. An outer diameter of the annular convex portion15dis about the same as an inner diameter of the insertion hole13cof the housing13. Therefore, when the circuit board12is inserted into the insertion hole13cand the grommet15is pushed into the insertion hole13c, the annular convex portion15dof the grommet15comes into close contact with an inner surface of the insertion hole13c. Such a close contact ensures watertightness inside the housing13.

The grommet15includes, for example, an annular convex portion15fin addition to the annular convex portion15d. The annular convex portion15dand the annular convex portion15fare arranged along the first direction D1, and the annular convex portion15fis in close contact with the inner surface of the insertion hole13cof the housing13together with the annular convex portion15d. Therefore, the watertightness of the housing13is more reliably ensured.

FIG. 5is a perspective view illustrating the housing13. An inner surface13qof the box-shaped portion13dof the housing13is provided with an engaged portion13jto which the circuit board12inserted into the insertion hole13cand accommodated in the internal space13bengages. The inner surface13qis a surface formed along the insertion hole13cand extends in both the first direction D1and the second direction D2. For example, a depth of a bottom surface of the box-shaped portion13dof the housing13becomes deeper as it approaches the inner surface13q.

The engaged portion13jis a rod-shaped portion that protrudes obliquely from the inner surface13q. As a result, the engaged portion13jhas a shape that easily bends in the third direction D3. The engaged portion13jis provided, for example, near the center of the inner surface13qin the first direction D1. The engaged portion13jhas, for example, a base portion13k, a rod-shaped portion13mextending obliquely from the base portion13k, and a tip portion13ppositioned on the rod-shaped portion13mopposite to the base portion13k. For example, the rod-shaped portion13mmay extend obliquely away from the insertion hole13c, and the tip portion13pmay be rounded.

FIG. 6is a perspective view illustrating the circuit board12engaged with the engaged portion13jof the housing13.FIG. 7is a plan view (viewed along the second direction D2) illustrating the circuit board12engaged with the engaged portion13jof the housing13. As illustrated inFIGS. 6 and 7, the circuit board12includes an engaging portion12dthat engages the engaged portion13jof the housing13. Note that inFIGS. 6 and 7, the grommet15is not illustrated.

The engaging portion12dis formed in a concave shape on the end surface of the circuit board12facing the second direction D2, for example. As an example, the engaging portion12dis provided on a tip side of the circuit board12in an insertion direction (right direction inFIG. 7) with respect to the center of the first direction D1of the circuit board12. The engaging portion12dhas, for example, an inclined surface12fthat is recessed obliquely from an end surface facing the second direction D2, a bottom surface12gthat is continuous with the inclined surface12f, and a wall portion12hthat stands up from the bottom surface12gon an opposite side of the inclined surface12f.

When the circuit board12is inserted into the internal space13bthrough the insertion hole13cwith respect to the housing13, a surface of the circuit board12opposite to the mounting surface of the light source11comes into contact with the rod-shaped portion13mof the engaged portion13j, and the engaged portion13jbends in the third direction D3. At this time, the engaged portion13jis elastically deformed in a direction approaching the inner surface13q.

Then, when the circuit board12is further inserted into the insertion hole13c, the elastic deformation is released by the rod-shaped portion13mentering the concave-shaped engaging portion12d. At this time, the tip portion13pof the engaged portion13jfaces the wall portion12hof the engaging portion12dalong the first direction D1, so that even if the circuit board12is pulled, the wall portion12hcomes into contact with the tip portion13pand the disconnection is suppressed. Since the engaging portion12dis caught and engaged with the engaged portion13jin this way, the engaged portion13jand the engaging portion12dcan function as a retainer for the circuit board12. Note that the shapes of the engaging portion12dand the engaged portion13jare not limited to the above examples and can be changed as appropriate.

Next, a method of manufacturing the lamp unit according to the present embodiment will be described. An example of assembling the lamp unit1described above will be described below. For example, as illustrated inFIG. 2, in a state in which the circuit board12, the housing13, the lens14, and the grommet15are disassembled, first, the lens14is attached to the housing13before the circuit board12is inserted into the housing13(process of attaching the lens).

For example, the lens14is fixed to the housing13by placing the lens14on the opening13hof the housing13and welding the lens14to the housing13. As a specific example, after the lens14is placed on the opening13hof the housing13, the housing13and the lens14are heated and vibrated to perform the welding. In addition, the housing13and the lens14may be annealed. In this case, the housing13and the lens14are placed in a furnace and heated.

On the other hand, the circuit board12on which the light source11and the receptacle portion17are mounted, the connector portion16is inserted into the receptacle portion17, and the harness18is connected is passed through the hole portion15cof the grommet15. Then, the circuit board12is inserted from the outside of the housing13into the insertion hole13cof the housing13to which the lens14is attached (process of inserting the circuit board).

When the circuit board12is inserted into the insertion hole13cof the housing13, the circuit board12elastically deforms the engaged portion13jof the housing13in the direction approaching the inner surface13qas illustrated inFIGS. 6 and 7, and then, the engaged portion13jenters the engaging portion12dof the circuit board12, and the circuit board12engages with the housing13. The circuit board12inserted into the insertion hole13cof the housing13is neither heated nor vibrated, for example. After the circuit board12is inserted into the insertion hole13cof the housing13and engaged with the engaged portion13j, a series of processes for manufacturing the lamp unit1is completed.

Next, the action and effect obtained from the lamp unit1and the manufacturing method according to the present embodiment will be described. The lamp unit1has the housing13in which the internal space13bfor accommodating the circuit board12on which the light source11is mounted is formed, and the housing13has the insertion hole13cfor inserting the circuit board12into the internal space13bfrom the outside of the housing13to which the lens14is attached. Therefore, in the lamp unit1, since the lens14can be attached to the housing13before the circuit board12is inserted into the insertion hole13c, the heat and vibration can be prevented from being applied to the circuit board12.

Therefore, since it is possible to prevent solder cracks from occurring in the circuit board12and damage to the electronic components mounted on the circuit board12, the quality of the lamp unit1can be improved. In addition, when the lamp unit1is subjected to the annealing treatment, only the lens14and the housing13can be annealed before the circuit board12is inserted, so that the number of lamp units1that can be placed in the furnace can be increased. Therefore, since more lamp units1can be manufactured by one annealing treatment, the lamp unit1can be manufactured efficiently.

In addition, the circuit board12may have the engaging portion12dthat engages with the housing13in the internal space13b, and the housing13may have the engaged portion13jon which the engaging portion12dis caught in the internal space13b. In this case, the engaging portion12dof the circuit board12inserted into the internal space13bof the housing13via the insertion hole13cengages with the engaged portion13jof the housing13. Therefore, since the circuit board12can be inserted from the insertion hole13cand the engaging portion12dcan be easily engaged with the engaged portion13jof the housing13, the lamp unit1can be easily assembled. Therefore, the lamp unit1can be manufactured more efficiently.

As illustrated inFIGS. 1 and 2, the lamp unit1includes the feeding harness18extending from the circuit board12and the grommet15where the circuit board12and the harness18are inserted, and the grommet15may seal the insertion hole13cwith the circuit board12inserted into the internal space13b. In this case, the grommet15seals the insertion hole13cof the housing13in a state in which the circuit board12is accommodated in the internal space13bof the housing13.

Therefore, when the grommet15seals the insertion hole13c, it is possible to suppress an intrusion of water or the like into the internal space13bof the housing13, so that a waterproof effect can be exhibited. In addition, by pushing the grommet15into the insertion hole13cin the state in which the circuit board12is inserted into the internal space13b, since the grommet15can be mounted at the same time as the circuit board12is mounted, the lamp unit1can be easily assembled.

In the method for manufacturing the lamp unit according to the present embodiment, the lens14is preliminarily attached to the housing13of the lamp unit1in the process of attaching the lens. After that, the circuit board12on which the light source11is mounted is inserted from the outside through the insertion hole13cinto the internal space13bof the housing13to which the lens14is preliminarily attached.

Therefore, since the lens14is attached to the housing13before the circuit board12is inserted into the insertion hole13c, the heat and vibration are not applied to the circuit board12when the lens14is attached to the housing13. As a result, since damage to the circuit board12is avoided, the quality of the lamp unit1can be improved. In addition, since only the housing13and the lens14can be annealed when the lens14is attached to the housing13, the number of lamp units1to be put in the furnace at the time of the annealing treatment can be increased. Therefore, since more lamp units1can be manufactured by one annealing treatment, the manufacturing can be performed efficiently.

The embodiment of the lamp unit according to the present disclosure has been described above. However, the present disclosure is not limited to the above-described embodiment, and may be modified or applied to other things without changing the gist described in each claim. That is, the shape, size, material, number, and arrangement of each portion of the lamp unit according to the present disclosure, and the content and order of each process of the method for manufacturing the lamp unit can be appropriately changed within the scope of the above gist.

For example, in the above-described embodiment, the lamp unit1that constitutes the BSM unit and is attached to the side surface of the visor of the outer mirror facing the vehicle body side has been described. However, the lamp unit according to the present disclosure may be a lamp unit attached to something other than the outer mirror, and can be applied to something other than the BSM unit, and further to something other than the vehicle body.