GB2348858A

GB2348858A - A head up display (HUD) for a mass-produced motor vehicle

Info

Publication number: GB2348858A
Application number: GB0008900A
Authority: GB
Inventors: Hillary Gil Sillitto
Original assignee: Thales Optronics Ltd
Current assignee: Thales Optronics Ltd
Priority date: 1999-04-14
Filing date: 2000-04-12
Publication date: 2000-10-18
Anticipated expiration: 2020-04-12
Also published as: DE10020140A1; GB9908415D0; GB0008900D0; GB2348858B

Abstract

A head up display (HUD) for a mass-produced motor vehicle comprises a display source (14) for projecting an image, detected by, for example, a CCD camera (20) in the visible and/or infra-red wave bands and<BR> ```a transparent combiner (18) for displaying the projected image in superimposition with the users view of the real world through the combiner (18) when in a deployed or in-use position. The combiner (18) is mounted on an arm which is adapted to move along its length to move the combiner (18) from a retracted or out-of-use position to the deployed position where the combiner (18) is organised and arranged to display the projected image.

Description

HEAD UP DISPLAY The present invention relates to a head up display (HUD). In particular, the present invention relates to a HUD for a mass-produced motor vehicle such as a car or truck, which includes a transparent combiner for displaying a projected image, wherein the combiner is adapted to move between a retracted or out-of-use position and a deployed or in-use position.

HUD's have been proposed for use in mass-produced motor vehicles such as cars. However, a number of problems have been encountered in attempting to put such proposals into practice. One of the main problems is that there is a lack of space for the location of the proposed HUD's in modern cars, particularly in luxury cars including a poweroperated sun roof, roof-mounted multiple light consoles, alarm sensor consoles and the like. This is further hampered by the safety regulations, which require a defined clearance between a user's head and an object protruding from the car roof into the cabin of the car, such that the driver is not injured in the event of an accident.

Furthermore, proposed HUD's comprise a number of separate components which require a skilled operator to mount the HUD in the motor vehicle, and require calibration of the HUD before it can be used. This is time consuming and impractical in mass-produced motor vehicles constructed on an assembly line.

It is amongst the objects of the present invention to obviate or mitigate at least one of the foregoing disadvantages.

According to a first aspect of the present invention, there is provided a head up display (HUD) for a massproduced motor vehicle, the HUD comprising: a display source for projecting an image in the visible waveband; and a transparent combiner for displaying the projected image in superimposition with the users view of the real world through the combiner when in a deployed or in-use position, the combiner being mounted on an arm which is adapted to move along its length to move the combiner from a retracted or out-of-use position to the deployed position where the combiner is organised and arranged to display the projected image.

Preferably, the HUD further comprises mounting means for mounting the arm to the display source. Alternatively, the arm may be mounted to the vehicle separately from the display source. When deployed the combiner is fixed in position and held to an accuracy of 0. 5 milli radians (which equates to 1 pixel at the display source) in order to minimise the misalignment between the scene viewed with the naked eye and that projected by the display source.

Preferably, in the retracted position, the combiner is disposed adjacent to the vehicle windscreen and tilted away from a user of the HUD, and in the deployed position the combiner is disposed in front of and tilted towards the user. Typically the combiner moves within an envelope of about 100 mm maximum distance normal to the windscreen in order to meet vehiclesafety requirements. Alternatively, in the retracted position, the combiner may be disposed adjacent to the roof of the vehicle and tilted towards the user. In a further alternative the combiner is disposed at a fixed angle with respect to the arm in both the retracted and the deployed positions. Conveniently, the combiner rotates relative to the arm from the retracted position to the deployed position. The combiner may rotate simultaneously with the arm as it moves along its length.

Alternatively, the arm may move along its length and the combiner may subsequently rotate to the deployed position.

Preferably, the HUD further comprises an image detector for detecting the image to be projected onto the combiner by the display source. The image defector may include an image intensifier. Preferably, the image detector is adapted to receive radiation emissions in the infra-red spectrum. Conveniently, the image detector is a CCD camera which is sensitive to radiation in both the visible and infra-red wavebands.

The HUD may further comprise a radiation source for emitting radiation in the infra-red spectrum to be reflected and subsequently received by the image detector.

The radiation source may be a lamp disposed on the vehicle, or a bulb disposed within a headlight of the vehicle.

Alternatively, the image detector may receive naturallyemitted radiation in the infra-red spectrum.

Preferably, the camera is mounted in line with the line of sight of the user of the HUD. The camera may be mounted on the combiner. Alternatively, the camera may be mounted on the arm of the HUD. In a further alternative, the camera may be mounted on the vehicle separately from the HUD.

Preferably, the arm is mounted on mounting means which comprise a bearing such as a linear bearing or slide to facilitate movement of the arm between the retracted position and the deployed position. The mounting means may alternatively comprise a V-bracket coupled to the display source and a number of roller bearings adapted to engage the arm of the HUD.

The HUD may further comprise a motor for moving the arm along its length. Conveniently, the HUD further comprises a rack and pinion assembly to facilitate movement of the arm. The rack may be formed on an outer surface of the arm, and the pinion may be coupled to the motor to translate rotational motion of the motor to lateral movement of the arm along its length. Conveniently, the HUD further comprises a mechanical link cable connecting the motor to a cam and follower assembly adapted to rotate the combiner with respect to the arm. Alternatively, the HUD may further comprise a second motor adapted to rotate the combiner with respect to the arm to the deployed position.

The display source may be a cathode ray tube (CRT) with appropriate projection optics. Alternatively, the display source may be inherently digital, such as a liquid display device (utilising transmission or reflective technology) with appropriate projection optics.

Typically, the viewing angle of the display is of the order of 18 degrees.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a view of a HUD in accordance with an embodiment of the present invention, shown mounted in a motor vehicle, and shown with a mounting arm and a combiner of the HUD in both a first, retracted position and a second, deployed position; Fig. 2 is a side view of part of the HUD of Fig. 1, shown with the combiner and the mounting arm in the deployed position; Fig. 3 is a bottom view of the part of the HUD shown in Fig. 2; Fig. 4 is a bottom view of the mounting arm and combiner of Fig. 1 shown in the retracted position; Fig. 5A is a perspective view of part of the HUD of Fig. 1, showing a mounting bracket of the HUD ; Fig. 5B is a rear view of the mounting bracket of Fig.

5A; Fig. 6 is a side view of an alternative retracting arm, combiner and camera of a HUD in accordance with an alternative embodiment of the present invention, showing the mounting arm and the combiner of the HUD in both a first retracted position and a second, deployed position; Fig. 7 is a view of the HUD of Fig. 1 shown with the cfombiner in an alternative retracted position; Fig. 8 is a bottom view of part of a HUD in accordance with an alternative embodiment of the present invention; and Fig. 9 is a side view of the HUD of Fig. 7.

Referring firstly to Fig. 1, there is shown a HUD indicated generally by reference numeral 10, mounted to the inside roof 12 of the cabin of a car (not shown). The HUD 10 is shown mounted in a right hand drive car on the right hand side of the drivers eye position 9.

The HUD 10 comprises a display source 14, (such as a CRT or back lit liquid crystal display with appropriate projection optics), a retractable arm assembly 16, and a rotatable transparent combiner 18. A camera 20 is provided as will be explained to provide the source 14 with an image to be displayed. The combiner 18 is rotatably mounted on an end 22 of the arm assembly 16, to rotate from a retracted, out of use position (indicated by the letter A in Fig. 1) to a deployed position (indicated by the letter B in Fig. 1). In the retracted position, the combiner 18 is folded adjacent to the roof 12 and in the deployed position, the combiner 18 is folded in front of the driver, and tilted towards him. The combiner 18 is moved to the deployed position by the arm assembly 16 extending from the retracted position (A), to the deployed position (B), in response to the driver activating the HUD 10 as will be explained.

The HUD 10 is associated with a night vision system which includes the camera 20 and a radiation source (not shown), such as a bulb located in the headlamp assembly of the car, which emits radiation in the infra-red spectrum.

This radiation is reflected from objects in front of the car and is received by the camera 20. The camera 20 also receives naturally emitted radiation in the infra-red spectrum. An infra-red image of the objects in front of the car is generated by the camera 20 and this image is fed electronically to the display source 14 where it is projected as a visible-spectrum image, possibly with image enhancement, to be displayed on the combiner 18 where the image is viewed by the driver in superimposition with the driver's naked eye view of the real world through the combiner 18 and through the windscreen 24.

Thus, visibility of objects in front of the car viewed by the driver with the naked eye is assisted by the generation of an infra-red-converted image displayed on the combiner and viewed simultaneously by the driver, giving the driver an enhanced view of the road ahead, particularly in low-light conditions, such as night time conditions.

This is typically achieved by the source 14 projecting the visible-spectrum image collimated to a distance of 30 or 40 metres.

The camera 20 is preferably mounted on or in the arm assembly 16, ideally on the drivers line of sight.

Accordingly windscreen 24 if laminated is preferably laminated using a non IR-absorbing plastic sheet between the two glass layers for structural integrity of the laminate plus a thin film coating which is IR absorbing (to limit heat build-up within the vehicle) but with a cut-out in the thin film coating to enable transmission of infrared radiation to the camera 20. Normally in a laminated windscreen the two glass layers are separated by a comparatively thick layer of plastics material which is infra-red absorbing to reduce the heat load within the cabin of the car.

There follows a more detailed description of the HUD 10 of the present invention.

Referring now to Fig. 2, the inside roof 12 of the car carries a roof lining 26 which is moulded to follow the inside roof 12, and to provide a gap 28 between the roof 12 and the lining 26 for the location of electrical wiring etc. The source 14 is mounted in a recess in the lining 26, using suitable mounting brackets or the like, such that part of the source 14 resides above the lining 26 and in the gap 28, and part of the source 14 resides below the lining 26 and protrudes into the cabin of the car through the recess (not shown) in the lining 26. The source 14 is tilted laterally towards the driver and downwards, to project the image onto the combiner 18. The retractable arm assembly 16 is mounted to the source 14 at a point above the lining 26, within the gap 28, and protrudes into the cabin from the front of the lining at a point below the header rail 30 which is at the junction between the roof 12 and the windscreen 24.

In Fig. 2, the arm assembly 16 is shown in the deployed position, corresponding to the position indicated by letter B in Fig. 1 and is disposed such that, in the event of the car being involved in an accident which causes a driver's airbag (not shown) to inflate, the combiner 18 is caused to rotate away from the driver by a rear surface of the airbag as it inflates. This prevents injury to the driver caused by the driver's head striking the combiner 18. Also, because the combiner 18 is disposed tilted away from the driver in the retracted position, this prevents injury to the driver if such an accident occurs during deployment of the combiner 18.

Fig. 3 shows the relative positioning of the source 14, the retractable arm assembly 16 and the combiner 18 in a car having a sunroof 32, with the roof lining 26 removed, for clarity, and with the combiner in the deployed position.

Referring now to Fig. 4, the retractable arm assembly 16 is shown with the combiner 18 in the retracted position corresponding to position A in Fig. 1. The arm assembly 16 comprises a hollow, elongate tube or arm 34, connected at one end 22 to a transverse hollow combiner mounting tube 36. A bracket 38 extending between tubes 34,36 stabilises the assembly 16. The combiner 18 is coupled to a bearing assembly 40 mounted within the tube 36 to facilitate rotation of the combiner 18 relative to the tube 36 between the retracted and deployed positions. The bearing assembly 40 is coupled to a motor 42 via a mechanical link cable 44, such as a Bowden (TM) cable and includes a helical cam and follower arrangement (not shown) for rotating the combiner 18. Thus the combiner 18 is rotated by the motor 42, link cable 44 and the helical cam and follower arrangement, when the HUD 10 is activated, to rotate the combiner to the deployed position.

The motor 42, which conveniently is a stepper motor, also simultaneously moves the arm assembly 16 from the retracted position to the deployed position, via a rack and pinion arrangement (not shown). Of course, motor 42 may alternatively take other forms, and for example may be a solenoid. To facilitate this movement, the arm assembly 16 includes a mounting tube 46, see Fig. 1, in which the elongate tube 34 is mounted. Bearings 48 and 50 are located between the tubes 34,46, to facilitate the movement of the tube 34 along is length to the deployed position.

In this way, when the HUD 10 is activated by the driver, the retractable arm assembly 16 extends from the retracted position to the deployed position by the elongate tube 34 moving along its length to project to a greater extent from the tube 46 whilst the combiner 18 rotates relative to the tubes 34,36 to the deployed position.

When the driver no longer requires the HUD 10, the HUD is de-activated and the tube 34 of the arm assembly 16 and the combiner 18 retract to the retracted position.

The HUD 10 is provided as a single unit which can be mounted directly in a car manufactured on a mass-production assembly line, therefore reducing the installation time to levels acceptable to the car manufacturer, and reducing the requirement of calibration of the HUD 10 which would be required if the components of the HUD were installed separately.

Referring now to Fig. 5A, there is shown the source 14 and a mounting bracket 52 which mounts the hollow elongate tube 34 of the retractable arm assembly 16 directly to the source 14, without the need for the mounting tube 46. The mounting bracket 52 is coupled to the source 14 and permits the tube 34 to move along its length from the retracted to the deployed position of Fig. 1 via a number of bearings 54, as can be seen more clearly in the enlarged view of the mounting bracket 52 shown in Fig. 5B. The mounting bracket 52 includes a V-shaped base 56 coupled to the source 14 and an L-shaped retaining arm 58, which extends from the base 56 to define a passageway 60 along which the tube 34 may traverse being guided by three equi-spaced bearings 34.

The bearings 54 are roller bearings.

Referring now to Fig. 6, there is shown an alternative retractable arm assembly 116 for a HUD which includes a combiner 118, wherein the combiner 118 moves between a retracted position A and a deployed position B. The combiner 118 is disposed in a fixed rotational orientation with respect to the hollow elongate tube 134 of the arm assembly 116, and in the retracted position (shown at A) is disposed out of the line of sight of the driver.

Referring now to Fig. 7, there is shown an alternative HUD 210 of similar structure and operation to the HUD 10 of Fig. 1, however the HUD 210 includes a combiner 218 which, in the retracted position (shown at A in Fig. 7) is disposed adjacent to the roof lining 26'of the car and tilted towards the driver. Thus it will be understood that the combiner 218 rotates from the retracted position A, where it lies adjacent to the roof lining 26, to the deployed position B, by rotating in the opposite direction from the combiner 18 of Fig. 1.

Referring now to Figs. 8 and 9 there is shown a HUD 310 in accordance with an alternative embodiment of the present invention. The HUD 310 comprises a source 314, a mounting assembly 312 and a combiner 318. The HUD 310 is mounted to the roof 12 of a car having a windscreen 24 and sunroof 32. The mounting assembly 312 comprises mounting arms 316 which are mounted to tracks 317 disposed in the gap 28 above roof lining 26, via bearings 319. The arms 316 move along the tracks 317 when the HUD 310 is activated, to move the combiner 318 from a retracted position to the deployed position of Figs. 8 and 9. The combiner 318 is rotatably mounted to a combiner mounting arm 321. In the retracted position (not shown), the arms 316 are retracted above roof lining 26, and combiner 318 is disposed adjacent to the roof 12 and windscreen 24, and tilted away from the driver. In the deployed position shown, the combiner 318 is disposed at an angle to the arms 316, such that the driver may view an image projected by source 314. The arms 316 are moved between retracted and deployed positions via a suitable motor (not shown), which also rotates the combiner 318 via a suitable helical cam and follower arrangement (not shown). The source 314 is mounted in the roof lining 26 separately from the mounting assembly 312. Alternatively, the source 314 may be mounted to the assembly 312.

Various modifications may be made to the foregoing within the scope of the present invention.

For example, the camera 20 may be mounted to the vehicle separately from the HUD but preferably on the drivers line of sight. The HUD may include a second motor to rotate the combiner between retracted and deployed positions. The display source may be a liquid crystal display (LCD). The arm assembly 16 of the HUD may be mounted to the source 14 via a bracket, support tube, or any other suitable means. The arm assembly 16 may be moved between retracted and deployed positions via a screwthreaded drive shaft or the like. The HUD may be located in any suitable vehicle, such as a bus, truck, van, coach or the like, and may be of suitable dimensions to suit the specific vehicle.

Claims

CLAIMS 1. A head up display (HUD) for a mass-produced motor vehicle, the HUD comprising: a display source for projecting an image in the visible waveband; and a transparent combiner for displaying the projected image in superimposition with the users view of the real world through the combiner when in a deployed or in-use position, the combiner being mounted on an arm which is adapted to move along its length to move the combiner from a retracted or out-of-use position to the deployed position where the combiner is organised and arranged to display the projected image.
2. A head-up display as claimed in claim 1, wherein when deployed the combiner is fixed in position and held to an accuracy of +0. 5 milli radians (which equates to 1 pixel at the display source) in order to minimise the misalignment between the scene viewed with the naked eye and that projected by the display source.
3. A head-up display as claimed in either preceding claim, wherein in the retracted position, the combiner is disposed adjacent to the vehicle windscreen and tilted away from a user of the HUD, and in the deployed position the combiner is disposed in front of and tilted towards the user.
4. A head-up display as claimed in either preceding claim, wherein the combiner moves within an envelope of about 100 mm maximum distance normal to the windscreen.
5. A head-up display as claimed in either preceding claim, wherein the HUD further comprises an image detector for detecting the image to be projected onto the combiner by the display source.
6. A head-up display as claimed in claim 5, wherein the image detector is a CCD camera which is sensitive to radiation in both the visible and infra-red wavebands.
7. A head-up display as claimed in claim 6, wherein the camera is mounted in line with the line of sight of the user of the HUD.