GB2266374A

GB2266374A - Display apparatus

Info

Publication number: GB2266374A
Application number: GB9304648A
Authority: GB
Inventors: Morgan Daniel Murphy; Robert Joseph Myers
Original assignee: Delco Electronics LLC
Current assignee: Delco Electronics LLC
Priority date: 1992-04-21
Filing date: 1993-03-08
Publication date: 1993-10-27
Also published as: GB9304648D0

Abstract

A vehicle instrument panel 18 is illuminated from behind by a light source 16 and carries a gauge 42 on its rear side whose spindle 24 projects through the panel and carries a pointer 22 which moves across the front of the panel. Pointer 22 is constructed as a light pipe with a forward facing surface 26 coaxial with the spindle and illuminated by a second light source 38. Light from source 38 passes through surface 26 and is reflected internally at surface 28 to illuminate the body of the pointer. As shown source 38 is located in a shielded casing 40 forward of panel 18, but it may be located behind the panel using an extended light pipe (Fig. 3). A front window 20 is part- transparent, so that the display is hidden-until-lit. In Fig. 4 additional illuminated signals are displayed in the same unit, using an inclined half-silvered mirror in front of the main panel. <IMAGE>

Description

DISPLAY APPARATUS This invention pertains to displays apparatus, for example to an instrumentation display suitable for implementation in an automotive vehicle.

In designing automobiles, designers sometimes implement alternative designs into the vehicle instrumentation panel. One such alternative design is the "hidden-until-lit" instrumentation display. In these types of displays, the display remains invisible to the vehicle driver until power is supplied to the display, which usually occurs on ignition of the vehicle. Some of these "hidden-until-lit" displays involve electronic displays and others involve more conventional analogue displays. Providing a good-looking "hidden-until-lit" analogue display typically requires expensive components, such as a gauge pointer within which a bright light source is incorporated, which increases the cost of the display.

The present invention seeks to provide improved display apparatus.

According to an aspect of the present invention there is provided display apparatus comprising a housing; a panel mounted within the housing and including at a first side a viewing surface substantially facing a viewing direction of the display apparatus and at a second side a lighting surface through which in use light passes to illuminate portions of the viewing surface; a first light source disposed on the lighting surface side of the panel for supplying light to the lighting surface of the panel; a gauge disposed on the lighting surface side of the panel and including a spindle extending through an aperture in the panel; a pointer mounted on the spindle at the viewing surface side of the panel and including a light receiving surface disposed substantially coaxially with the spindle and substantially facing the viewing direction, at least one reflective surface and a light emitting surface for emitting light entering-from the light receiving surface of the pointer; a second light source adapted in use to transmit light to the light receiving surface of the pointer; and a cover for preventing viewing of the panel and the pointer when the first and second light sources are unlit and for enabling viewing of the panel and the pointer when the first and second light sources are lit.

This apparatus can provide a high performing "hidden-until-lit" display which includes brightly backlit graphics characters and a brightly lit light pipe pointer in implementations relatively inexpensive to construct.

This invention can also provide a hidden-until-lit instrumentation display which includes an analogue gauge which is well lit to the vehicle driver when power is supplied to the display, but invisible to the vehicle driver when no power is supplied to the display. The display can have a relatively inexpensive construction and may be implemented in a compact display unit.

A preferred embodiment comprises a graphics panel with a viewing surface facing a display direction and a lighting surface opposite the viewing surface for receiving light which illuminates the graphics. A first light source is provided for lighting the panel from the lighting surface side of the panel. An analogue gauge is mounted proximal to the lighting surface and includes a spindle protruding through the panel. A light pipe pointer is mounted to the spindle on the viewing surface side of the panel and has a light receiving surface centred on the spindle axis and facing the display direction. A second light source for lighting the light pipe pointer is preferably mounted proximate and facing the light receiving surface.A housing contains the above described elements and may include at the front thereof a partially transparent, partially opaque cover preventing viewing of the pointer, the mount for the second light source and the panel when the light sources are not lit but through which the panel and pointer are visible when the light sources are lit.

An embodiment of the present invention is described below, by way of illustration only, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view in cross-section of an embodiment of instrument display; Figure 2 is a side elevational view in cross-section of a second embodiment of instrument display; Figure 3 is a side elevational view in cross-section of a third embodiment of instrument display; Figure 4 is a side elevational view in cross-section of a fourth embodiment of instrument display; and Figure 5 shows an embodiment of instrument display as fitted in a vehicle.

Referring to Figure 1, an embodiment of instrument display generally includes an analogue gauge 42, a light pipe pointer 22, a graphics panel 18 and light sources 16 and 38, all mounted within a housing 10. A partially transparent cover 20 through which the display is viewed is mounted on the front of housing 10.

A circuit board 14 is mounted within housing 10 and supports light source 16 and analogue gauge 42, both of which are electrically connected to circuit board 14 in a manner well known to those skilled in the art. The display panel 18 is mounted with its light receiving surface 17 facing the light source 16 and the analogue gauge 42 and with its viewing surface 19 facing the display direction. Spindle 24 of the analogue gauge 42 protrudes through an opening in the display panel 18 so that the light pipe pointer 22 may be attached to the spindle 24 on the viewing surface side of panel 18 as shown.

Light source 16 and reflector 12 together form means for backlighting the panel 18 by shining light onto the light receiving surface 17 of the panel 18. The panel 18 is viewed from the side of viewing surface 19 and, when backlit, shows lit graphics symbols in which, for example, either the graphics characters themselves are lit or the background is lit and the graphics characters appear as blacked-out shadows. The display panel 18 is of a type well known to those skilled in the art.

One way of constructing a display panel such as panel 18 is to provide a generally transparent or translucent panel and apply thereon an opaque mask, for example an opaque paint, in patterns to black out the portions of the panel 18 not intended to be lit.

Filtering may be provided in the panel 18 to provide colouring for the whole or portions of panel 18 when backlit.

The light pipe pointer 22 is attached to the gauge spindle 24 as shown and is formed of a light transmitting material having a light receiving surface 26 centred on the axis of the spindle 24 facing the display direction as shown. Light source 38 is mounted proximate the light receiving portion 26 on the axis of the spindle 24 opposite the light pipe pointer 22 from the panel 18 and provides light to the light pipe pointer 22 via light receiving surface 26. The light from light source 38 travels into the light pipe pointer 22 and is reflected off of reflecting surface 28 into the arm of the light pipe pointer 22. The light then generally reflects off of surface 30 and out of exit surface 32 so that the pointer 22 appears brightly lit.

The axial positioning of light source 38 provides uniformly bright lighting of the pointer 22 throughout all rotational positions of the pointer 22.

Plastics body 44 retains the light piping portions of the light pipe pointer 22 and is opaque to prevent light leaks around the axial portions of the pointer. Light source 38 is supported by support 34 having an arm 36 extending over the axis of the spindle 24 as shown. An opaque plastics cap 40 mounted on light source 38 prevents light leaks from the light source in all directions except towards the light receiving surface 26 of the pointer 22. The support 34 is fixedly mounted to the panel 18 in any suitable manner well known to those skilled in the art.

The cover 20 comprises any suitable partially transmissive, partially opaque, lens. In one implementation, cover 20 is moulded from a dark coloured plastics material with 50 percent or less light transmissivity. In another implementation, a layer of dark coloured plastics material is applied to a conventional clear cover.

The cover 20 prevents viewing of display panel 18, pointer 22 and pointer support 34 when no power is supplied to the display, providing the appearance of a plain dark panel to the vehicle driver. When power is supplied to the display so that light sources 38 and 16 are lit, the pointer 22 and graphics characters of panel 18 become visible to a viewer of the display through the cover 20. The support 34 and other unlit portions of the display remain invisible to a viewer of the display through cover 20.

In the above manner, a high performance hidden-until-lit display which is compact and cost efficient can be provided. The compactness of the display is achieved, in part, through the placement of light source 38 for the light pipe pointer 22, eliminating the need for a light source located between the gauge 42 and the panel 18 and thereby reducing the required thickness of the display. In addition, the axial placement of the light source 38 with respect to pointer 22 provides bright lighting of pointer 22, through all rotational positions thereof, eliminating the need for a bright light source to be incorporated within the arm of pointer 22 itself, as done in certain prior art implementations.

A further advantage associated with the elimination of the need for a bright light source incorporated within the arm of pointer 22 is the simplified attachment of the pointer 22 to the spindle 24. During attachment of pointer 22 to spindle 24, there is no need for attachment of electric power supply wires to the pointer 22 itself, as required in implementations in which a light source is incorporated within the arm of the pointer.

Figure 2 illustrates another embodiment of instrument display. The support 35 is mounted to the panel 18 through a snap mount 14, which may be integrally moulded in the panel 18 or otherwise fastened thereto. Power is supplied to the light source 38 from circuit board 14 through lines 50 (only one shown) and terminals 48 (only one shown). Power reaches the light source 38 from terminals 48 by any one of a number of suitable means including wires embedded in the support 35 or conductive traces applied to the outside of support 35 leading to light source 38.

Referring to Figure 3, an alternative implementation of the gauge and lit pointer is shown with a light source 58 used in place of light source 38 and mounted on the circuit board 60 instead of out in front of the pointer 22. The light from light source 58 is piped to the light receiving surface 26 of light pipe pointer 22 through light pipe 51. Light pipe 51 has a first surface 53 proximate light source 58, a second surface 55 proximate and facing the light receiving surface 26, and internal reflecting surfaces 52 mounted at 45 degree angles to the direction of light travel.

An opaque light shield 56 prevents the light from light source 58 from backlighting the display panel 18, allowing independent lighting of the panel 18 through means such as light source 16 and reflector 12 shown in Figure 1. A generally opaque plastics light cap 54 is snapped into position around light pipe 51 as shown to block light leaks from light pipe 51 so that light pipe 51 remains invisible to a viewer of the display.

The embodiment shown in Figure 4 provides a two-page display, in which the portion of the display similar to Figure 1 provides a first page of information and the portion of the display new to this Figure provides a second page of information. In this embodiment the cover glass 86 is generally transparent and would not prevent the viewing of the pointer 22 and panel 18. Rather, the "hiding" function is performed by partially silvered mirror 90. Partially silvered mirror 90 is coated with a reflective coating 91 to have approximately 50 percent reflectivity and 50 percent transmissivity. Reflective coating 91 may comprise any suitable reflective coating material, including aluminium and silver.

In this manner, when light sources 38 and 16 are not lit, partially silvered mirror 90 prevents viewing of light pipe pointer 22, support 34 and panel 18. However, when power is applied to the display so that light sources 16 and 38 are lit, the light pipe pointer 22 and the backlit graphics of panel 18 become visible through the partially silvered mirror 90.

Included with the display is a second circuit board 74 connected to the first circuit board 14 through connector 72. Mounted on the second circuit board 74 is a display panel 76 such as a vacuum fluorescent display.

The display panel 76, mounted orthogonal to the panel 18, provides a brightly lit electronic display that is reflected off of partially silvered mirror 90 and viewed through substantially transparent cover glass 86. In the implementation shown, the partially silvered mirror 90 is placed at 450 to both the display panel 76 and graphics panel 18, providing a virtual image 77 to a viewer of the display through cover 86. The virtual image 77 is a mirror image of the display panel 76 and in this implementation, appears on substantially the same plane as graphics panel 18. However, the positioning of display 76 can be adjusted so that the image appears on a different plane from that of panel 18.

A bank of warning lights 78 provides warning information in the form of virtual image 85 reflected off of partially silvered mirror 90 Any suitable method of warning may suffice. In the example shown, each warning light (only one of which is shown) comprises a light source 80 with a reflector 82 to light selectively warning graphics on panel 84 providing warning information to a driver of the vehicle. Also included in the display is a PRNDL display 88 (giving an indication of the selected gear ratio of an automatic transmission) which is always visible and is easily implemented by one skilled in the art.

In the two page display described in Figure 4, the analogue and electronic displays may either be operated simultaneously to provide analogue gauge and electronic information together to the viewer or may be selectively viewed so that the viewer has a choice of which information to access or a choice of a combination of information comprising part analogue and part electronic information.

Figure 5 shows how the instrument displays of the examples set forth above are implemented in a motor vehicle instrument panel 104 and viewable by a vehicle driver 106.

In the preferred implementations for the above described displays, the light sources are incandescent bulbs, but any suitable bright light sources, including LEDs and halogen light sources, are considered equivalents. The displays described above have a single analogue gauge with one lit pointer. However, actual implementations may include two or more of the above described displays positioned side-by-side or in some other relative positional relationship to provide a full range of information to the vehicle driver.

The disclosure of our co-pending British patent application No. 930LL7il,b (RJ/3787) filed the same day as this application is incorporated herein by reference.

Claims

Claims:

1. Display apparatus comprising a housing; a panel mounted within the housing and including at a first side a viewing surface substantially facing a viewing direction of the display apparatus and at a second side a lighting surface through which in use light passes to illuminate portions of the viewing surface; a first light source disposed on the lighting surface side of the panel for supplying light to the lighting surface of the panel; a gauge disposed on the lighting surface side of the panel and including a spindle extending through an aperture in the panel; a pointer mounted on the spindle at the viewing surface side of the panel and including a light receiving surface disposed substantially coaxially with the spindle and substantially facing the viewing direction, at least one reflective surface and a light emitting surface for emitting light entering from the light receiving surface of the pointer; a second light source adapted in use to transmit light to the light receiving surface of the pointer; and a cover for preventing viewing of the panel and the pointer when the first and second light sources are unlit and for enabling viewing of the panel and the pointer when the first and second light sources are lit.

2. Display apparatus according to claim 1, wherein the second light source is mounted proximate and facing the light receiving surface of the pointer, the apparatus comprising support means for supporting the second light source substantially coaxially with the spindle of the gauge.

3. Display apparatus according to claim 2, wherein the support means for the second light source is mounted on the panel.

4. Display apparatus according to claim 3, wherein the support means is mounted to the panel with a snap-fit.

5. Display apparatus according to claim 1, comprising a circuit board on which the gauge and the first and second light sources are mounted and a light pipe including a first surface proximate the second light source and a second surface proximate the light receiving surface of the pointer, the light pipe in use transmitting light from the second light source to the light receiving surface of the pointer.

6. Display apparatus according to claim 5, comprising a light shield for preventing the second light source from illuminating the panel.

7. Display apparatus according to claim 5 or 6, comprising an opaque light cap for preventing light leakage from the light pipe and for ensuring that the light pipe is not visible through the cover.

8. Display apparatus according to any preceding claim, wherein the cover has a light transmissivity of less than substantially 50 percent.

9. Display apparatus according to claim 8, wherein the cover is formed of partially transparent plastics material.

10. Display apparatus according to any one of claims 1 to 7, wherein the cover comprises a partially silvered mirror.

11. Display apparatus according to claim 10, comprising second display means in use providing an image which is reflected off of the partially silvered mirror.

12. Display apparatus according to any preceding claim, wherein the first and/or second light sources comprise an incandescent bulb.

13. Display apparatus according to any preceding claim, wherein the first light source comprises a reflector.

14. Display apparatus substantially as hereinbefore described with reference to and as illustrated in Figure 1, 2, 3 or 4 of the accompanying drawings.