Patent Application
20150158422
This disclosure generally relates to a light-pipe suitable for use in a vehicle instrument panel assembly, and more particularly relates to a light-pipe cut from a sheet of light-transmissive material.
It is known to form a light-pipe using injection molding processes. However, if a thin (<3 mm) but larger area (>100 sq-mm) light-pipe is needed, injection molding a part with such an aspect ratio can be difficult and expensive.
In accordance with one embodiment, a vehicle instrument panel assembly is provided. The assembly includes a light source and a light-pipe. The light-pipe is configured to guide light emitted from the light source to a location on the assembly remote from the light source. The light-pipe is cut from a sheet of light-transmissive material.
In another embodiment, a light-pipe suitable for use in a vehicle instrument panel assembly is provided. The light-pipe is configured to guide light emitted from a light source to a location on the assembly remote from the light source. The light-pipe is cut from a sheet of light-transmissive material.
In yet another embodiment, a method of forming a light-pipe suitable for use in a vehicle instrument panel assembly is provided. The method includes the step of providing a sheet of light-transmissive material. The method also includes the step of cutting the light-pipe from the sheet.
Further features and advantages will appear more clearly on a reading of the following detailed description of the preferred embodiment, which is given by way of non-limiting example only and with reference to the accompanying drawings.
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
In order to illuminate or backlight the applique 18, the assembly 12 includes a light source 28. By way of example and not limitation, the light source 28 may be a plurality of light emitting diodes (LEDs). The LEDs may be mounted onto a circuit board 30. The LED's may be operated (turned ON, turned OFF) individually to, for example, illuminate one of the graphics such as a high-beam indictor, or may be operated in groups to, for example, illuminate the numerals to which the pointer 26 points. The circuit board 30 may be formed of the well-known FR-4 circuit board material with conductor traces formed of copper foil. The LED's may be attached to the circuit board 30 by soldering, as will be recognized by those in the art. The assembly 12 may include a gasket 32 that defines openings 34 separated by barriers 36 so light emitted by an LED intended to illuminate, for example, the high-beam indicator does not ‘leak’ and undesirably illuminate an adjacent graphic such as a low-tire-pressure indicator.
The a light-pipe 40 configured to guide light emitted from the light source 28 to a location on the assembly 12 remote from the light source 28. In general, the idea of using transparent or light-transmissive material such as a clear acrylic to form a light-pipe is known. Typically, light-pipes are formed by injection molding a light-transmissive material. However, as is the case in the example instrument panel assembly shown, the height or thickness 42 (
The light-pipe 40 may be advantageously formed by cutting the light-pipe 40 from a sheet (i.e. sheet stock) of light-transmissive material. A description of how to cut a sheet of light-transmissive material is presented in a co-owned U.S. Pat. No. 5,645,666 issued to Jones on Jul. 8, 1997, the entire contents of which are hereby incorporated by reference herein. By way of example and not limitation, a suitable sheet material from which the light-pipe can be cut is available from PLASKOLITE Inc. of Columbus, Ohio, USA, Item # 1AG000QA in a thickness of 1.50 mm. It is recognize that the sheet material may also include a coating on one or both sides of the sheet to promote propagation of light through the light-pipe 40.
Continuing to refer to
In the non-limiting example illustrated in
With the LED's arranged about the perimeter of the light-pipe 40 being configured to emit light into the cut end 48 of the segments 50 that form the light-pipe, it is generally preferable for the cut end 48 to normal or perpendicular to the plane 52. That way, light propagating through the segments 50 propagates in a direction that is generally parallel to the cut edge 46 and upper and lower surface of the segments 50 so that the majority of light is reflected back toward the interior of the segment as opposed to escaping from the segment through the cut edge 46 and upper and lower surface of the segments 50.
To direct light from the light-pipe 40 toward the applique 18 to illuminate the indicia 24 of the applique 18, the end of each of the segments 50 opposite the cut end 48 may advantageously include a beveled portion 54 configure to direct light traveling through each of the segments 50 toward the applique. By way of further explanation and not limitation, the beveled portion 54 may be characterized as being at an angle substantially less than normal relative to the plane 52 defined by the sheet or the light-pipe 40. As used herein, an angle substantially less than normal includes angles from thirty degrees (30°) to sixty degrees (60°). Preferably, the angle of the beveled portion is forty-five degrees (45°) relative to the plane 52. It is recognized that 45° would generally provide for the greatest light intensity, but other angles could be used to spread the light in any of the segments 50 over a larger area of the applique 18. In this way, the size of the indicia 24 is not limited by the thickness 42 of the light-pipe.
Accordingly, the applique 18 may be configured to define a translucent section 56 that define the indicia 24 and are positioned to align with the beveled portion 54 when the assembly is assembled as shown in
Referring again to
Step 510, PROVIDE SHEET OF LIGHT-TRANSMISSIVE MATERIAL, may include unrolling a sheet of light-transmissive material from a roll of the material.
Step 520, PROVIDE LASER, may include programing a laser 62 based cutting machine with the data or coordinates necessary to define the shape of the object (e.g. the light-pipe 40) that is going to be produced by cutting the sheet provided.
Step 530, MAKE 90° CUTS, may include adjusting the direction of the laser 62 to make cuts normal to the plane 52, and making the cuts in the sheet material that define the cut edge 46 and cut end 48 of the segments 50. cutting the light-pipe from the sheet.
Step 540, MAKE 45° CUTS, may include adjusting the direction of the laser 62 to make cuts at 45° to the plane 52, and making the cuts in the sheet material that define the beveled portion 54 of the segments 50.
Accordingly, a vehicle instrument panel assembly (the assembly 12), a light-pipe 40 for the assembly 12, and a method 500 of forming a light-pipe suitable for use in a vehicle instrument panel assembly is provided. By cutting the light-pipe 40 from sheet stock, the light-pipe 40 can be made thinner than is economically feasible using traditional injection molding techniques. Furthermore, by using a laser 62 to cut the light pipe from the sheet stock, the various edges (cut edge 46, cut end 48, and beveled portion 54) will have surface finishes that are advantageous for the performance of the light-pipe 40 without any additional edge polishing processes.
While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.
