GB2472269A

GB2472269A - Illuminated pointer display

Info

Publication number: GB2472269A
Application number: GB0913418A
Authority: GB
Inventors: Samir Mezouari
Original assignee: Visteon Global Technologies Inc
Current assignee: Visteon Global Technologies Inc
Priority date: 2009-07-31
Filing date: 2009-07-31
Publication date: 2011-02-02
Anticipated expiration: 2029-07-31
Also published as: GB0913418D0; GB2472269B

Abstract

Illuminating a pointer arm and display area using a light source to illuminate the shaft of a rotatable pointer; the shaft acts as a light pipe to convey light within the shaft in order to illuminate the display area and the pointer arm of the rotatable pointer. The display area and pointer arm can be illuminated by using a reflective cover portion which conceals the shaft of the rotatable pointer, wherein a first portion of light is deflected along the pointer arm from the shaft and a second portion of light is reflected off the cover portion to illuminate the display area. Alternatively the shaft may have a notch between its two ends such that the notch causes the light to be deflected out of the shaft and onto the display area. The notch may extend around the circumference of the shaft. The pointer arm may be formed of the same light transmissive material as the shaft. The light may be separated at a junction between the pointer arm and the shaft. The cover may have reflective underside or be translucent and have a reflective coating on its upper surface. The light source may be a light emitting diode.

Description

Pointer Display

BACKGROUND

a. Field of the Invention

The present invention relates to a pointer display and method for illuminating a pointer arm and display area, and more specifically to a pointer display and method for use in a motor vehicle display.

b. Related Art Currently, it is more common for a vehicle instrument panel to be back-lit as this does not require lighting components to be mounted in front of the instruments. In these instrument clusters, the design of the display is relatively complex, as portions of the display area, in particular the display indicia, must be translucent in order to permit light, from light sources placed behind the display panel, to shine through the required regions to illuminate the display. In addition, back lighting usually requires a plurality of light sources to illuminate the whole area of the display and a further, more complex arrangement is required to illuminate the pointer.

It is known that front-lit panels have an improved appearance over backlit panels and furthermore the information bearing surface of the display can have a simpler design. However, additional costs and complexity arise from the requirement for flexible connectors and light guides to direct the light from the light sources to the required areas of the display. Furthermore, the problem remains of how to illuminate the display area evenly. Front lighting from a point source often produces shadows, making certain regions of the display too dark to be clearly visible to a viewer of the display.

SUMMARY OF THE INVENTION

According to the invention, there is provided a pointer display comprising: -a display area; -a rotatable pointer, the pointer having a shaft and a pointer arm, the pointer arm extending away from the shaft; -means for rotating the rotatable pointer; -a light source for illuminating the pointer arm and the display area; and -a cover, the cover being arranged to conceal part of the rotatable pointer about the shaft and having a reflective portion; wherein the shaft of the pointer is arranged to receive light from the light source, the pointer shaft acting as a light pipe to convey within the shaft said received light, a first portion of said conveyed light being deflected along the pointer arm to illuminate the pointer arm and a second portion of said conveyed light escaping from the pointer and being directed to illuminate the display area after reflection from the reflective portion of the cover.

Also according to the invention, there is provided a pointer display comprising: -a display area; -a rotatable pointer including a shaft, the shaft having a first end and a second end and having a notch between said first and second ends; -means for rotating the rotatable pointer; and -a light source for illuminating the pointer and the display area; wherein the shaft of the pointer is arranged to receive light from the light source at the first end, the pointer shaft acting as a light pipe to convey within the shaft said received light to the second end, and a portion of said conveyed light being deflected by the notch out of the shaft before reaching said second end to illuminate the display area.

Also according to the invention there is provided a method of illuminating a pointer arm and display area, the method comprising: -providing a pointer having a shaft and a pointer arm, the pointer arm extending away from the shaft; -providing a light source arranged to project light into a first end of said shaft; -providing a cover at a second end of said shaft, the cover having a reflective portion; -conveying said projected light from the first end of the shaft to the second end; -deflecting a first portion of said conveyed light along the pointer arm to illuminate said arm; and -directing a second portion of said conveyed light to illuminate the display area after reflection from the reflective portion of the cover.

Also according to the invention, there is provided a method of illuminating a display area, the method comprising: -providing a pointer including a shaft, the shaft having a first end and a second end and having a notch between said first and second ends; -providing a light source arranged to project light into said first end; -conveying said projected light from the first end of the shaft to the second end; and -deflecting, using said notch, a portion of said conveyed light out of the shaft before reaching said second end to directly illuminate the display area.

Preferably the pointer arm acts as a light pipe to convey the first portion of light within the pointer arm towards an end of the pointer arm. It may then be advantageous to make the pointer arm and shaft from the same light transmissive material.

Alternatively it may be desirable to deflect the first portion of light to externally illuminate the pointer arm, in which case the pointer arm may be made from an opaque material.

In a preferred embodiment, the reflective portion of the cover is a reflective underside of the cover. However, it may be desirable to make the cover from a translucent material in which case the reflective portion may be a reflective coating on an upper surface of the cover.

For simplicity the light source may be mounted behind the display area.

In a preferred embodiment, the second portion of light escapes from the pointer at a junction between the shaft and pointer arm.

Because the pointer display of the present invention only requires a single light source to illuminate both the pointer arm and the display area, the light source may be a single light emitting diode.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a plan view of an automotive display unit including a dial display; Figure 2 is a cross-sectional view of one embodiment of a pointer display of the present invention; and Figure 3 is a cross-sectional view of a second embodiment of a pointer display of the present invention.

DETAILED DESCRIPTION

Figure 1 shows an automotive main display unit 1 having a dial display 2. The dial display 2 includes a centre dial 3 having main display area 5 on which are a plurality of display indicia 7. In this example, the display indicia 7 comprise a series of scale marks and numbers indicating the speed of the vehicle. Because the display area 5 and indicia 7 are not transparent or translucent, this portion of the dial 3 needs to be illuminated from the front of the display area 5.

A rotatable pointer 9 is provided in the centre of the dial 3. The rotatable pointer 9 comprises a shaft 11 that extends perpendicularly from the front face of the display area 5. In this example, the shaft 11 is rod-shaped and has a substantially cylindrical outer surface. A pointer arm 13 is rigidly connected at its first end 15 to an upper portion 17 of the shaft 11, and extends outwards from the shaft 11 approximately perpendicularly to the rotational axis 19 of the shaft 11. In this example, the pointer arm 13 is integrally formed with the shaft 11.

A sloped surface 21 in the upper portion 17 of the shaft 11 and in particular the region of intersection of the shaft 11 and pointer arm 13 forms both a top surface of the upper portion 17 of the shaft 11 and an end surface of the arm 13. The function of the sloped surface 21 will be described hereinafter.

The pointer arm 13 has a substantially rectangular vertical cross-section and the width of the pointer arm 13 is substantially less than its depth. In addition, as shown in Figure 2, the pointer arm 13 is tapered so that the thickness of the arm 13 is greater at the first end 15 of the arm 13 than at the second, distal end 23.

The length of the pointer arm 13 is such that the second end 23 of the arm 13 overlies at least a part of the display indicia 7. Means 25 for rotating the pointer 9 are provided, and in this example include a shaftless stepper motor 25. The stepper motor is linked to sensors (not shown) that detect the speed of the vehicle (not shown). In this way, as the vehicle speed changes, signals from the sensors cause the pointer 9 to rotate, and the pointer arm 13 covers different values on the display indicia 7 indicating different vehicle speeds.

A cover or cap 27 is provided above the shaft 11 of the pointer 9 to conceal the shaft 11 from a viewer of the display 2. As shown in Figure 2, the cover 27 is a substantially flat circular disc and covers the shaft 11 and a part of the pointer arm 13 proximal its first end 15. In this example the cover 27 is mounted on mounting means (not shown) such that the cover 27 rotates with the pointer 9. In alternative embodiments the cover 27 may be mounted so that the cover 27 stays stationary with respect to the rotation of the pointer 9. The cover 27 includes a reflective portion 29, which in this example is a reflective layer 29 on the underside 31 of the cover 27 adjacent the top surface of the pointer shaft 11. The reflective layer 29 of the cover 27 may be formed from any suitable reflective material, such as a metallic foil layer, or may be formed by painting the underside 31 of the cover 27

white for example.

The pointer shaft 11 and pointer arm 13 are both formed from light transmissive materials. In this embodiment the arm 13 and shaft 11 are formed from the same light transmissive material, which is preferably acrylic or polycarbonate.

A light source 33, in this example a light emitting diode (LED), is located adjacent a first or lower end 35 of the pointer shaft 11, and is arranged to project light into the first end 35 of the shaft 11. The light source 33 may be mounted behind the dial display 2. The shaft 11 acts as a light pipe and conveys the light from the first end 35 to the upper region 17 of the shaft 11.

At the top of the shaft 11, some of the light is deflected by the sloped surface 21 so that this deflected portion of the light travels along the pointer arm 13, as shown in Figure 2. In this embodiment, as the pointer arm 13 is also formed of a light transmissive material, it acts as a second light pipe and the deflected portion of the light is conveyed within the pointer arm 13 to the second end 23 of the arm 13, such that the entire length of the pointer arm 13 is illuminated. The proportion of the light that is deflected by the sloped surface 21 along the pointer arm 13 will depend on the angle between the sloped surface 21 and the axis 19 of the shaft 11 and also the angle of incidence of the light that strikes the sloped surface 21.

The majority of the light that is not deflected by the sloped surface 21 escapes from the pointer 9 in the upper region 17 of the shaft 11. This second portion of light is reflected by the reflective layer 29 of the cover 27 and directed towards the dial display area 5. The reflection may be due to specular reflection or diffuse reflection (scattering) or a combination of both. The reflected light therefore illuminates the display area 5, in particular the display indicia 7, from the front of the display 2.

Because the light escaping the upper portion 17 of the pointer shaft 11 strikes the underside 31 of the cover 27 at different angles, the reflected light is diffuse and evenly illuminates the display area 5.

In a preferred embodiment, the cover 27 is formed from an opaque material so that a viewer of the display 2 does not see light directly from the light source 33, but only after reflection by the cover 27 or deflection along the pointer arm 13.

It will be appreciated that the cover 27 may be of any suitable size and shape to fulfil the above-described functions. For example the cover 27 may be curved so that the underside 31 of the cover 27 has a concave profile, or the cover 27 may be conical or in the shape of a truncated cone. Furthermore the horizontal cross-sectional shape of the cover 27 may not be circular, but may be hexagonal or any other desired shape.

In the embodiment described hereinbefore, the cover 27 is opaque with a reflective layer 29 on the underside 31. In alternative embodiments, the cover 27 may be made from a translucent or transparent material. The reflective portion 29 may then comprise a reflective coating or layer on the upper surface 37 of the cover 27. In these embodiments, light escaping from the upper portion 17 of the shaft 11 travels through the thickness of the cover 27 and is reflected by the reflective coating and directed towards the dial display area 5.

In one embodiment, the shaft 11 of the pointer 9 is designed such that there is minimal loss of light along the length of the shaft 11, and most of the light being conveyed in the shaft 11 propagates along the shaft 11 by total internal reflection.

If light were able to escape along the length of the shaft 11 not only would less light be available to illuminate both the pointer arm 13 and the dial display area 5, but minimising the amount of light escaping from the shaft 11 in this way decreases the formation of a light halo around the shaft 11 and cover 27, or a region of bright light in the centre of the dial display area 5.

It will be appreciated that the description of the pointer 9 hereinbefore is one example only. In alternative embodiments, the shaft 11 and pointer arm 13 may not be integrally formed and the first end 15 of the pointer arm 13 may be positioned on top of the shaft 11 or the pointer arm 13 may extend from the side of the shaft 11 at a distance from the top of the shaft 11. Additionally, when the shaft and pointer arm are not integrally formed they may be made from different materials. In some embodiments, the shaft 11 may have an opaque coating (not shown) on the outer surface to reduce or eliminate light loss along the length of the shaft 11.

In one embodiment of the invention, the pointer arm 13 is connected to the side of the pointer shaft 11. Deflection means are provided in the shaft 11 of the pointer 9 that deflects a portion of the light conveyed in the shaft 11 towards the pointer arm 13. In this example, this first portion of the light escapes from a side of the shaft 11 adjacent the first end of the pointer arm 13 and externally illuminates the pointer arm 13. The pointer arm may be formed of a translucent or opaque material, and may be painted white or have a reflective coating so that the light also reflects off the surface of the pointer arm 13.

Figure 3 shows a further embodiment of the present invention, and similar features to those described hereinbefore have been shown with reference numerals incremented by 100. In this example, the shaft 111 includes a circumferential notch 41 extending around the shaft 111. The notch 41 has a V-shaped cross-section and in this example the depth of the notch 41 is approximately one third of the diameter of the shaft 111 at this point.

The notch 41 acts to deflect a portion of the light conveyed within the shaft 111 radially out of the shaft 111 to directly illuminate at least a part of the display area 105. The notch 41 may be of any suitable depth and cross-sectional shape such that the required amount of light is deflected out of the shaft 111 at this point and such that the deflected light illuminates the required region of the display area 105 without reflecting off the reflective portion 129.

The notch 41 may not extend fully around the circumference of the shaft 111, so that the deflected light illuminates a sector of the display area 105. Furthermore, the shaft 111 may include more than one notch 41 spaced along the length of the shaftill.

The light that is not deflected by the notch 41 continues to the upper region 117 of -10 -the shaft 111. At the top of the shaft 111, a second portion of the light is deflected by the sloped surface 121 to illuminate the pointer arm 113, as described previously. A third portion of light not deflected by the sloped surface 121 then escapes from the pointer 109 in the upper region 117 of the shaft 111, this third portion of light being reflected by the reflective layer 129 of the cover 127 and directed towards the dial display area 105.

An advantage of the display pointer 9 of the present invention is that both the display area 5 and the pointer arm 13 may be illuminated with a single light source 33. Furthermore, the display area 5 is evenly lit due to the diffuse reflection of the light by the cover 27.

The invention therefore provides a convenient and economical arrangement and method for front illuminating a display area in conjunction with an illuminated pointer arm. -11 -

Claims

CLAIMS1. A pointer display comprising: -a display area; -a rotatable pointer, the pointer having a shaft and a pointer arm, the pointer arm extending away from the shaft; -means for rotating the rotatable pointer; -a light source for illuminating the pointer arm and the display area; and a cover, the cover being arranged to conceal part of the rotatable pointer about the shaft and having a reflective portion; wherein the shaft of the pointer is arranged to receive light from the light source, the pointer shaft acting as a light pipe to convey within the shaft said received light, a first portion of said conveyed light being deflected along the pointer arm to illuminate the pointer arm and a second portion of said conveyed light escaping from the pointer and being directed to illuminate the display area after reflection from the reflective portion of the cover.
2. A pointer display as claimed in any preceding claim, in which the shaft includes a notch to deflect a portion of said conveyed light out of the shaft to illuminate directly the display area.
3. A pointer display as claimed in Claim 2, in which the notch extends around a circumference of the shaft and said deflected portion of light is emitted in a radial direction from the shaft.
4. A pointer display comprising: -a display area; -a rotatable pointer including a shaft, the shaft having a first end and a second end and having a notch between said first and second ends; -means for rotating the rotatable pointer; and -a light source for illuminating the pointer and the display area; wherein the shaft of the pointer is arranged to receive light from the light source at -12 -the first end, the pointer shaft acting as a light pipe to convey within the shaft said received light to the second end, and a portion of said conveyed light being deflected by the notch out of the shaft before reaching said second end to illuminate the display area.
5. A pointer display as claimed in Claim 4, in which the notch extends around a circumference of the shaft.
6. A pointer display as claimed in Claim 4 or Claim 5, in which the pointer has a pointer arm, the pointer arm extending away from the shaft; and -a cover, the cover being arranged to conceal part of the rotatable pointer about the shaft and having a reflective portion; wherein a first portion of said conveyed light remaining in the shaft after deflection by the notch being deflected along the pointer arm to illuminate the pointer arm and a second portion of said conveyed light remaining in the shaft after deflection by the notch escaping from the pointer and being directed to illuminate the display area after reflection from the reflective portion of the cover.
7. A pointer display as claimed in any one of Claims 1 to 3 and 6, in which the pointer arm acts as a light pipe to convey the first portion of light within the pointer arm towards an end of the pointer arm.
8. A pointer display as claimed in Claim 7, in which the pointer arm and shaft are formed from the same light transmissive material.
9. A pointer display as claimed in any one of Claims 1 to 3 and 6, in which said first portion of light externally illuminates the pointer arm.
10. A pointer display as claimed in any one of Claims ito 3 and 6 to 9, in which the second portion of light escapes from the pointer at a junction between the shaft and pointer arm.
11. A pointer display as claimed in any preceding claim, in which the reflective portion of the cover is a reflective underside of the cover.
12. A pointer display as claimed in any of Claims ito 3, and 6 to 10 in which the cover is translucent and the reflective portion is a reflective coating on an upper surface of the cover.
13. A pointer display as claimed in any preceding claim, in which the light source is mounted behind the display area.
14. A pointer display as claimed in any preceding claim, in which the light source is a single light emitting diode.
15. A method of illuminating a pointer arm and display area, the method comprising: -providing a pointer having a shaft and a pointer arm, the pointer arm extending away from the shaft; -providing a light source arranged to project light into a first end of said shaft; -providing a cover at a second end of said shaft, the cover having a reflective portion; -conveying said projected light from the first end of the shaft to the second end; -deflecting a first portion of said conveyed light along the pointer arm to illuminate said arm; and -directing a second portion of said conveyed light to illuminate the display area after reflection from the reflective portion of the cover.
16. A method as claimed in Claim 15, in which the pointer shaft includes a notch and wherein the method further comprises deflecting a third portion of said conveyed light out of the shaft to illuminate the display area.
17. A method of illuminating a display area, the method comprising: -providing a pointer including a shaft, the shaft having a first end and a second end and having a notch between said first and second ends; -providing a light source arranged to project light into said first end; -conveying said projected light from the first end of the shaft to the second end; and -deflecting, using said notch, a portion of said conveyed light out of the shaft before reaching said second end to directly illuminate the display area.
18. A pointer display substantially as herein described with reference to or as shown in Figure 2.
19. A method of illuminating a pointer arm and display area substantially as herein described with reference to the accompanying drawings.