This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-059017 filed on Mar. 8, 2007, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a projector type lamp that can be used in a vehicular head-lamp.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2005-235419 discloses a projector type lamp. The projector type lamp includes: a casing formed with a front open end; a concave mirror formed on an inside face of the casing; a light source provided at or around the first focal point of the concave mirror; and a convex lens fitted in the front open end of the casing and configured to refract a reflected light that is emitted from the light source and reflected on the concave mirror so as to project a substantially parallel pencil beam forward from the project type lamp.
The casing is formed by connecting an upper casing member and a lower casing member together and fastening the casing members by screws.
In the conventional art, the casing members are coupled together and fastened by screws so that the convex lens is fixedly supported between the casing members. When fastening the casing members by screws to assemble the projector type lamp, assembly workers have to grasp the casing members tightly to prevent the convex lens from falling off the casing members. This makes the assembly of the projector type lamp difficult.
An aspect of the present invention provides a projector type lamp. The projector type lamp comprises a casing formed with a front open end, the casing formed by connecting an upper casing member and a lower casing member; a concave mirror formed on an inside face of the casing; a light source provided at or around the first focal point of the concave mirror; a convex lens configured to be held between the upper casing member and the lower casing member at the front open end of the casing and adapted to refract a reflected light that is emitted from the light source and reflected on the concave mirror so as to project a substantially parallel pencil beam forward from the project type lamp; provisional fixing members formed at the upper casing member and the lower casing member respectively and configured to latch one another so as to provisionally fix the casing members to one another; and a fastener configured to fasten the provisionally-fixed casing members together.
Embodiments according to the present invention will be described with reference to the drawings.
A projector type lamp of a first embodiment will be described with reference to
In
Next, the configuration of the projector type lamps 10a to 10j will be explained in detail with reference to
The projector type lamp 10 includes a tubular resin casing 14 formed with an opening at the front end, the resin convex projection lens 6 covering the front open end of the casing 14, and an LED 11 functioning as a light source fixed to the casing 14 via a base plate 9 (See
As shown in
A front portion of the upper casing member 12 functions as a reflector portion 7 and a back portion functions as an upper holding portion 15.
The upper holding portion 15 is formed in a horizontally extending tubular shape with its lower half cut off. An inside face of the upper holding portion 15 is formed with an upper groove 15a at the front end thereof which extends in the circumferential direction.
The reflector portion 7 is formed in a substantially half dome shape and formed with a concave mirror 7a on an inside face thereof. The concave mirror 7a is formed as a spheroidal surface or a free-curved surface that is base on a spheroidal surface.
A back portion of the lower casing member 13 functions as a shade 4 and a front portion functions as a lower holding portion 16.
The lower holding portion 16 is formed in a horizontally extending tubular shape with its upper half cut off. An inside face of the lower holding portion 16 is formed with a lower groove 16a at the front end thereof which extends in the circumferential direction.
The shade 4 of the lower casing member 13 extends from the rear end of the lower holding portion 16 and forms an L-shaped plate in a cross section.
A folded portion 4a of the L-shaped shade 4 is disposed at a second focal point F2 of the concave mirror 7a and has a scaling relationship with a cut line CL of a projection pattern LP (see
The lower casing member 13 and the upper casing member 12 are connected to each other to form the casing 14, so that a cylindrical holding portion (15, 16) is formed at the front portion of the casing 14 and a cylindrical groove (15a, 16a) is formed at the inside face of the front open end of the holding portion (15, 16).
The convex lens 6 is fixedly supported between the casing members 12, 13 to be held by casing 14 so that a flange 6a of the convex lens 6 is inserted and fitted in the cylindrical groove (15a, 16a) of the casing 14.
The convex lens 6 can be made of transparent thermoplastic resin such as polycarbonate resin or acrylate resin. The casing members 12, 13 forming the casing 14 may be made of light-blocking thermoplastic resin such as polycarbonate resin or acrylate resin. Thermoplastic resin has sufficient strength and is easily formed, so that the convex lens 6 and the casing members 12, 13 can be accurately molded. Preferably, the convex lens 6 is made of acrylate resin that has high-optical property.
The concave mirror 7a can be formed as a reflective layer by vapor-depositing, such as a silver reflective layer on the inside face of the upper casing member 12.
The LED 11 as a light source is disposed at a first focal point F1 of the concave mirror 7a such that a light emitting portion 11 a of the LED 11 faces the concave mirror 7a. An optical axis of the light emitting portion 11a is orthogonal to an optical axis Z of the lamp 10, that is, an optical axis Z of the concave mirror 7a. The first focal point F1 of the concave mirror 7a and the center of the convex lens 6 lie on the optical axis Z of the lamp 10.
A chamber in the casing 14 includes a front chamber 14a and a rear chamber 14b. The front chamber 14a is defined by the convex lens 6 and the upper holding portion 15 and the lower holing portion 16 so as to be in a substantially cylindrical shape. The rear chamber 14b is defined by an upper side 4b of the shade 4 and the concave mirror 7a so as to be in a substantially half dome shape.
As shown in
As shown in
A connecting direction of the provisional fixers 12d, 13d corresponds to a connecting direction of the casing members 12, 13. Those directions are shown vertically in
An assembly process of the projector type lamp 10 will be described with reference to
Firstly, the LED 11 is pre-assembled to the base plate 9, as shown in
Next, as shown in
Next, as shown in
When provisionally fixing the casing members 12, 13 to each other, the flange 6a of the convex lens 6 is inserted and fit in the cylindrical groove (15a, 16a) of the casing members 12, 13 such that the casing members 12, 13 hold the convex lens 6 in between.
Next, the flanges 12a, 13a of the casing members 12, 13 are fastened to each other by the screw 8 as the fastening step, and the assembling of the projector type lamp 10 is completed.
Next, all of the assembled projector type lamps 10 are mounted to the housing body 22 by the mounting brackets 23, and then the outer lens 21 is attached to the front open end of the housing body 22. With this process, the assembling of the head lamp A is completed.
In the respective projector type lamps 10a to 10j of the headlamp A, the light emitting portion 11a of the LED 11 emits light to the concave mirror 7a. The light is reflected on the concave mirror 7a, converged on the second focal point F2 of the concave mirror 7a at or around the edge 4a of the shade 4, refracted by the projector lens 6, and then projected forward from the respective project type lamps 10a to 10j.
The projected light is in the form of substantially pencil which has the projection pattern LP with the cut line CL (see
The projector type lamps 10a to 10j may have different projection patterns depending on mounting positions thereof in the headlamp.
Next, effects of the first embodiment will be explained.
According to the first embodiment, a projector type lamp 10 includes: a casing 14 formed with a front open end that is formed by connecting an upper casing member 12 and a lower casing member 13; a concave mirror 7a on an inside face of the casing 14 and having a surface formed as an ellipsoid of revolution or an elliptic free-curved surface; a light source 11 provided at or around the first focal point F1 of the concave mirror 7a; a convex lens 6 configured to be held between the upper casing member 12 and the lower casing member 13 at the front open end of the casing 14 and adapted to refract a reflected light that is emitted from the light source 11 and reflected on the concave mirror 7a so as to project a substantially parallel pencil beam forward from the project type lamp 10; provisional fixers 12d, 13d formed at the upper casing member 12 and the lower casing member 13 respectively and configured to latch one another so as to provisionally fix the casing members 12, 13 one another; and a fastening 8 configured to fasten the provisionally-fixed casing members 12, 13 together.
With this configuration, the casing members 12, 13 can be provisionally fixed to each other by the provisional fixers 12d, 13d thereof, prior to fastening of the casing members 12, 13 by the fastener 8. This makes the fastening operation of the casing members 12, 13 easy and improves operability of the projector type lamp 10 in assembly operations.
According to the projector type lamps 10a to 10j of the first embodiment, the provisional fixers 12d, 13d are a latch claw 13d and a latch hole 12d respectively. This simplifies the structures of the provisional fixers 12d, 13d and suppresses an increase of production cost.
According to the projector type lamp 10 of the first embodiment, a connecting direction of the provisional fixers 12d, 13d corresponds to a connecting direction of the casing members 12, 13.
With this structure, when connecting the casing members 12, 13 to each other, the provisional fixers 12d, 13d are also latched with each other. This improves the operability of the projector type lamp 10 in assembly operations.
Next, a second embodiment according to the present invention will be explained.
The projector type lamp 10 of the second embodiment does not include the cylindrical groove (15a, 16a) at the inside face of the front open end of the casing 14. Instead, a ring member 31 is provided to prevent the casing members 12, 13 from disassembling or separating from each other.
As shown in
A connecting direction of the ring member 31 to the front end of the casing corresponds to the optical axis Z of the projector type lamp 10. In other words, the connecting direction of the ring member 31 and the connecting direction of the casing members 12, 13 (the connecting direction of the provisional fixers 12d, 13d) are cross (perpendicular) to one another, that is, not parallel to one another. In the second embodiment, the connecting directions are at right angle to each other.
The ring member 31 is formed with a recess that opens toward the rear side and receives the flange 6 of the convex lens 6 and the front end of the casing 14 therein. In other wards, the ring member 31 is formed integrally with a cylindrical tubular portion 31a that has an inside face formed along the outside face of the flange 6a of the convex lens 6, and a flat plate portion 31b that extends from the front end of the tubular portion 31a toward an inner side of the tubular portion 31a.
The flange 6a of the convex lens 6 is received in the tubular portion 31a of the ring 31, and the flange 6a is sandwiched between the rear end face of the flat portion 31b of the ring member 31 and the front end face of the casing 14.
The ring member 31 is formed integrally with locking parts 33 that are adopted to latch with locking parts 35 that are formed at the upper casing member 12 and the lower casing member 13, respectively.
The locking parts 33, 35 are configured to maintain the connection of the ring member 31 to the casing 14, that is to say, to prevent detachment of the ring member 31 from the casing 14.
In this second embodiment, each of the locking parts 33 of the ring member 31 is formed as a latch claw 33 and each of the locking parts 35 of the casing members 12, 13 is formed as a latch hole 35 that catches the latch claw 33.
The latch claws 33 are formed at a rear end of an elastic arm 32 that project from the tubular portion 32.
In addition to the effects of the first embodiment, the second embodiment provides effects as described below.
According to the second embodiment, the projector type lamp 10 further includes the ring member 31 configured to fit around the front end of the casing 14 so as to enclose and tighten the casing members 12, 13. With this structure, the ring member 31 firmly tightens the front end of the provisionally fixed casing members 12, 13, together so that the fastening operation of the screw 8 becomes easier.
According to the second embodiment, the ring member 31 and the casing 14 are formed with locking parts 33, 35 respectively that latch each other. With this configuration, the ring member 31 does not fall off the casing 14, so that the fastening operation of the screw 8 becomes much easier.
According to the second embodiment, the connection direction of the ring member 31 to the casing 14 is the same as the connection direction of the locking parts 33, 35. With this structure, when the ring member 31 and the casing 14 are connected to each other, the locking parts 33, 35 are connected so as to be latched with each other. Therefore, the projector type lamp 10 provides improved efficiency in the assembling operations.
As described above, the present invention provides a projector type lamp with an improved assembly efficiency.
Although the present invention has been described above by reference to certain embodiments, the present invention is not limited to these embodiments. Modifications and variations of the embodiments can be made without departing from the spirit or scope of the appended claims. The embodiments are only for illustrative purposes and are not intended to limit the present invention.
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