This disclosure relates to motor vehicle instrument clusters and gauges. More particularly, a structure and assembly of a uniformly illuminated pointer for motor vehicle instrument clusters and gauges having an isotropic luminance that provides uniform intensity when viewed from all angles.

BACKGROUND ART

Motor vehicles usually include instrument clusters to display visual contents or information to a driver. An instrument cluster may have a cluster mask with several gauges that display information such as speed, level of fuel in fuel tank, engine rpm, amongst others. A pointer is used as an indicator to show the parameters on the gauge .

For safety reasons, a driver shall not keep his eyes off the road for prolonged period of time. Thus it is desirable to have an instrument cluster and more specifically, a pointer that allows the driver to view the readings of the gauge efficiently. Shape, size and structural design of a pointer may vary depending on desired outcome, such as uniform illumination of pointer, or aesthetic appearance such as three-dimensional effect when in operation .

One issue when designing a pointer adapted for a flat gauge surface is the problem of a non-homogenous light distribution within the illuminated pointer, which causes appearance of a dark area and results in the presence of hot spot. An existing method for solving hot spots problem include using printed foil on both top and bottom of the pointer shaft. However, such method increases material costs and uniform illumination effects are dependent on the size of pointer structure, for example, optimization of such techniques works best if pointer structure is relatively thin and long.

Another method is to work on the design of pointer structure, such as that disclosed in US 9499097 B2. US 9499097 B2 discloses a pointer for a vehicle instrument cluster and gauge that include design features in the pointer structure for uniform illumination. Structure of the pointer includes two curved light reflecting surfaces disposed adjacent to and contacting each other, so that light can be uniformly propagated to the pointer tip. While US 9499097 B2 discloses a manner of uniformly propagating light in a pointer, the structural design as disclosed in US 9499097 B2 does not produce an isotropic luminance, which allows an observer to easily read the parameters on a gauge.

In another example, US 20150151677 Al discloses a gauge assembly comprising of a curved gauge surface and a pointer assembly having a pointer bent at an end point which corresponds to the curve structure of the gauge surface, to produce a three-dimensional appearance. However, US 20150151677 Al does not solve the problem of adjusting the uniformity of illuminating a pointer.

It is therefore desirable to design and develop a pointer that achieves uniform reflection, providing a homogenously illuminated pointer for a gauge surface, in particular, a pointer that produces an isotropic luminance which allows a user or observer to view the pointer with the same intensity of brightness from all angle of view. SUMMARY OF INVENTION

In a first aspect, a pointer for a gauge of a motor vehicle is disclosed. The pointer comprises a hub to receive light rays supplied from a light source in a first direction and a shaft extending from the hub, the shaft having an arch extending within a body of the shaft, wherein light rays travelling through the shaft are diffused off the arch. Advantageously, the aforesaid pointer structure enables light rays to be kept within the pointer structure, thereby achieving a homogenously illuminated pointer when in operation.

In some implementations, the hub may have a reflective pane to reflect light received from the first direction to a second direction, towards the arch of the shaft. Once the light rays are received by the hub, the reflective pane reflects the light rays received in a first direction into a second direction, towards the arch of the pointer. This allows reflected light rays to be distributed towards the arch, of which the reflected light rays are diffused off the arch in multiple directions, achieving diffuse reflection due to the irregular surface and reflective characteristics of the arch. When describing reflective characteristics of the arch, diffuse reflection, as opposed to specular reflection, is meant. Specifically, the arch may possess lambertian properties to allow light rays to be diffused off the arch .

To achieve the above effect, the arch may be a reflective surface . The arch may be fabricated with a reflective material, or coated with a reflective material. An alternative method is to layer surface of the arch with a reflective printed foil . The reflective material may comprise porous particles or possess a measure of surface roughness so that light is able to diffuse. The arch may be positioned within the body of the shaft at a location suitable to catch most of the light rays travelling in the second direction. For example, the arch may be positioned in the middle of the shaft, towards a first end of the shaft nearer to the hub, or in the alternative, towards a second end of the shaft nearer to the tip of the pointer, according to desired results . The pointer may be made of transparent material, which enables light to propagate through the pointer, without scattering the light rays, such that light rays will not be diffused. Accordingly, an observer may be able to see the pointer when light travels through the pointer. An example of a suitable transparent material may be for example polycarbonate.

To improve the aesthetics of the pointer when viewed or observed by an observer, in particular to provide an isotropic luminance defining a geometrical outline of the pointer, it is possible to include an opaque portion in the pointer. An edge of the pointer may be transparent such that light rays propagating from the transparent edge define an outline of the pointer. Alternatively, the pointer may be completely transparent and may further include an opaque housing defining a geometrical shape of the pointer. The opaque housing may enclose the transparent pointer to an extent that light rays propagating from the transparent pointer define an outline of the pointer. The opaque housing may be of a shape corresponding to the pointer and covers the pointer to an extent that light is diffused out of the pointer around the edge of the housing to thereby define a geometrical outline of the pointer.

In a second aspect, a gauge assembly for motor vehicles is disclosed. The gauge assembly comprises a gauge surface to display visual contents; a pointer assembly to indicate a parameter on the gauge surface; and a stepper motor to support and provide rotational movement to the pointer assembly about an axis of the pointer assembly. The pointer assembly includes a light source to supply light rays and a pointer overlaying the gauge surface. The pointer further comprises a hub to receive light rays supplied from the light source in a first direction and a shaft extending from the hub, the shaft having an arch extending within a body of the shaft, wherein light rays propagating through the shaft are diffused off the arch. Advantageously, the introduction of an arch extending within the body of the pointer achieves a homogenously illuminated pointer when in operation.

The gauge surface may be a flat surface. The arch may be a reflective surface. The arch may be fabricated with a reflective material, or coated with a reflective material, for eg. a white reflective printed foil.

The pointer may be made of transparent material, which enables light to emit through the pointer, without scattering the light rays . Suitable type of transparent material may be for example polycarbonate .

Preferably, the hub may include a reflective pane to reflect light received from the first direction to a second direction, towards the arch of the shaft. The reflective pane reflects light rays received by the hub, from a first direction into a second direction, towards the arch of the pointer, thus allowing light rays to be diffused off the irregular surface area and reflective surface of the arch. This allows reflected light rays to be distributed towards the arch, of which the reflected light rays are diffused off the arch in multiple directions, achieving diffuse reflection due to the irregular surface area and reflective characteristics of the arch.

The pointer may further include an opaque housing defining a geometrical shape of the pointer, thereby enclosing light rays propagating from the uniformly or homogenously illuminated pointer within the opaque housing. Advantageously, the opaque housing defines a geometrical outline of the illumination from the homogenously illuminated pointer, providing a pointer with an isotropic luminance when observed from different angle of views .

In a third aspect, a motor vehicle having a gauge assembly as described is disclosed. Advantageously, a pointer with an isotropic luminance when observed from different angle of views is useful for night driving conditions for drivers, as well as motorcyclists .

DESCRIPTION OF DRAWINGS

Other objects and aspects will become apparent from the following description of embodiments with reference to the accompany drawings in which:

Fig. 1 shows a side view and an exploded view of a pointer according to a preferred embodiment.

Fig. 2a shows a top view of the pointer assembly on a gauge surface according to a preferred embodiment.

Fig. 2b shows a side view of a gauge assembly for motor vehicle comprising a pointer according to a preferred embodiment. Fig. 2c shows an exploded view of a gauge assembly for motor vehicle comprising a pointer according to a preferred embodiment.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments provided herein relate to a uniformly illuminated pointer having an isotropic outline.

With reference to Fig. 1 which shows a side view of a pointer 100 according to a preferred embodiment. The pointer 100 may be adapted for a gauge of a motor vehicle. Pointer 100 includes a hub 106 to receive light rays supplied from a light source 102 in a first direction A, as shown in Fig. 1. Suitable type of light sources may be for example, a light emitting diode (LED) . It shall be understood by a person skilled in the art the color of light emitting from the diode may vary according to design requirements. A shaft 108 extends from the hub 106. The shaft 108 has an arch 110 extending within a body of the shaft 108. Specifically, light rays reflected from the hub 106 propagate towards the arch 110, and are diffused in multiple directions within the shaft 108 due to an irregular surface provided by the arch 110.

The hub 106 has a reflective pane 112 to reflect light received from the first direction A to a second direction B, towards the arch of the shaft 106. The arch 110 is made of a reflective surface. This may be achieved during fabrication process, for example using a reflective material to fabricate the arch 110 or coating the arch 110 with a reflective material. Another possible method is to layer the arch with a reflective printed foil. The reflective printed foil may be white or near white in color. The pointer may include an opaque housing 116, also known as a pointer cap for defining a geometrical shape of the pointer 110. Conventionally, a pointer cap is used as a cover to protect pointer or pointer needle from dust and particles. In a preferred embodiment, the use of an opaque housing 116 or pointer cap encloses the light rays within the pointer 110. In this embodiment, the pointer 110 is transparent and comprises the opaque housing 116 enclosing the transparent pointer to an extent that light rays propagating from the transparent pointer define an outline of the pointer. Specifically, light rays reflected from the reflective pane 112 of the hub 106 is reflected towards the arch 110 of the shaft 108. Any light rays that emit towards the arch 110 are diffused off the arch 110 in multiple directions, within the body of the shaft 108, thereby producing a homogenously illuminated pointer. Due to the irregular surface area and reflective characteristics of the arch 110, light rays diffuses off the arch in multiple direction producing a uniform illumination. The opaque housing 116 encloses the light rays propagating from the pointer within the opaque housing 116, when in operation. This defines a geometrical outline of the pointer, thus achieving an isotropic luminance with substantially constant light intensity when viewed from different angles.

Fig. 2a which shows a top view of a gauge assembly 200a with a pointer assembly 202 according to the preferred embodiment as described above. From the top view, one may identify at least one part of the pointer assembly 202 visible against a flat gauge surface 204. In Fig. 2a, the pointer assembly 202 shown is relatively short, thick and small in size against the gauge assembly, compared to conventional pointers . It shall be apparent to a person skilled in the art that the position of the pointer assembly can be at different portions of a gauge assembly, according to design requirements. Referring now to Fig. 2b which shows a side view of a gauge assembly 200b with a pointer assembly 202 according to a preferred embodiment, wherein the pointer assembly 202 overlays a flat gauge surface 204, the flat gauge surface 204 configured to display visual contents. The pointer assembly 202 is configured to indicate a parameter on the flat gauge surface 204, to enable a user to easily view the readings on the gauge . The gauge assembly 200b may also include a stepper motor 206 to support and provide rotational movement to the pointer assembly 100 about an axis of the pointer assembly 202. The pointer assembly 202 may include a light source 210 for example, a light emitting diode (LED) , configured to supply light rays, and a pointer 212 (also refer to Fig. 1 for details) overlaying the flat gauge surface 204. The pointer 212 has a hub 214 to receive light rays supplied from the light source 210 in a first direction A. The pointer 212 further comprises a shaft 216 extending from the hub 214, the shaft 216 having an arch 218 extending within a body of the shaft 216. Light rays propagating through the shaft are diffused off the arch 218.

Additionally, the hub 214 has a reflective pane 224 to reflect light received from the first direction A to a second direction B, towards the arch 218. The arch may be a reflective surface fabricated from reflective materials, or coated with reflective materials. Alternatively, a reflective printed foil may be used for layering the arch. Due to the irregular surface area and reflective characteristics of the arch 218, light rays reflected from reflective pane 224 onto the arch 218 are diffused off in multiple directions and contained with pointer, producing a uniform or homogenously illuminated pointer. The pointer 212 may be made of transparent material such as polycarbonate, thus enabling light to emit through the pointer 212, without scattering the light rays. The pointer assembly 202 may include an opaque housing 222 to define a geometrical shape of the pointer 212. The effect of the opaque housing encloses light rays propagating from the pointer, thus outlining the geometrical shape of the pointer. An isotropic luminance outlining the geometrical shape of the pointer is observed, allowing an observer to view the pointer with an isotropic luminance when observed from different angles of view. Additionally, the gauge assembly 200b may be electrically connected to a printed circuit board (PCB) 220 for supplying power to the gauge assembly 200b. It shall be understood by a person skilled in the art the PCB may be a separate circuitry or directly connected to the gauge assembly 200b.

Fig. 2c shows an exploded side view of a gauge assembly 200c according to a preferred embodiment. The gauge assembly 200c comprises of an opaque housing 222, a pointer 212 having a hub 214 with a reflective pane 224. The hub 214 is configured to receive light rays supplied from a light source 210, such as a light emitting diode (LED) . Preferably the LED may be white or near white in color. However, the color of the LED may vary according to design requirements. The pointer 212 has a shaft 216 extending from the hub 214. The shaft 216 has an arch 218 extending within a body of the pointer 212. When in operation, light rays supplied from 210 into hub 214 is reflected from a first direction A into a second direction B (refer to Fig. 1), towards the arch 218 by the reflective pane 224. The light rays that touch a surface of the arch are diffused in multiple directions within the shaft 216. A homogenously illuminated pointer is thus achieved. The pointer as described above overlays a flat gauge surface 204. The gauge assembly 200c may include a light housing 206. The light housing 206 may be a white or near white, with reflective properties. A stepper motor 208 supports the pointer 212 and its components thereof, and provide rotational movement about an axis of the pointer. The gauge assembly 200c may be electrically connected to a printed circuit board (PCB) 220.

When in operation, a homogenous illumination emitting from the pointer 212 outlines the geographical shape of the pointer 212 due to the opaque housing 222, which encloses the homogenously illuminated pointer, defining a geometrical shape of the pointer 212 against a flat gauge surface 204, thereby producing an isotropic luminance with substantially constant intensity of illumination outlining the pointer when observed.

While the preferred embodiment and alternative embodiments of the invention have been disclosed and described in detail herein, it may be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope thereof.