Optical Apparatus, Modules and Devices

Examples of the disclosure relate to optical apparatus, modules, and devices. The optical apparatus includes a control panel and at least one light guide. The at least one light guide includes at least; a diffractive in-coupler configured to in-couple one or more input beams of light into the light guide from a first light engine, an expander configured to expand the one or more input beams of light, and an out-coupler configured to out-couple the one or more expanded beams of light from the light guide. The at least one light guide is transparent and is provided overlaying at least part of the control panel and is configured to display virtual images at a longer focal distance than the control panel.

TECHNOLOGICAL FIELD

Examples of the disclosure relate to optical apparatus, modules and devices. Some relate to optical apparatus, modules and devices for providing images within a vehicle such as an automobile or an aircraft.

BACKGROUND

Vehicles such as automobiles or aircraft comprise control panels that a user needs to look at while they are controlling the vehicle. When a user views the control panel they need to look away from the environment around them. When the user then looks back at the environment it can take some time for their eyes to adjust to the different focal distances of objects in the environment.

BRIEF SUMMARY

According to various, but not necessarily all, examples of the disclosure there is provided an apparatus comprising:a control panel;at least one light guiding means comprising at least; in-coupling diffractive means configured to in-couple one or more input beams of light into the light guiding means from a first light engine, expanding means configured to expand the one or more input beams of light, and out-coupling diffractive means configured to out-couple the one or more expanded beams of light from the light guiding means;wherein the at least one light guiding means is transparent and is provided overlaying at least part of the control panel and is configured to display one or more virtual images at a longer focal distance than the control panel.

The apparatus may comprise a plurality of light guiding means arranged in a stacked configuration.

The apparatus may comprise a plurality of light guiding means where a first light guiding means is configured to display a virtual image at a first focal distance and a second light guiding means is configured to display a virtual image at a second focal distance.

The control panel and the plurality of light guiding means may be configured so that the images at different focal distances provide one or more volumetric images.

The apparatus may comprise a head-up display.

The focal distance of the light guiding means overlaying the control panel may be aligned to a focal distance of the head-up display.

A gap may be provided between the at least one light guiding means and the control panel.

The at least one light guiding means may be provided directly over the control panel.

The apparatus may comprise means for adjusting the focal distance of one or more virtual images provided by the apparatus.

The focal distance of the at least one light guiding means may be set to infinity.

The focal distance of the at least one light guiding means may be set to a far or middle distance.

The apparatus may be configured to enable the focal distance of the at least one light guiding means to be adjusted.

The at least one light guiding means may be configured to display a first image for a user's first eye and a second image for a user's second eye.

According to various, but not necessarily all, examples of the disclosure there is provided an apparatus comprising:a control panel;at least one light guide comprising at least; in-coupling diffractive elements configured to in-couple one or more input beams of light into the light guide from a first light engine, one or more expanders configured to expand the one or more input beams of light, and out-coupling diffractive elements configured to out-couple the one or more expanded beams of light from the light guide;wherein the at least one light guide is transparent and is provided overlaying at least part of the control panel and is configured to display virtual images at a longer focal distance than the control panel.

According to various, but not necessarily all, examples of the disclosure there may be provided a module, a device, a vehicle or cab for a vehicle comprising an apparatus as described herein.

DETAILED DESCRIPTION

FIG.1shows an example light guiding means101that can be used in examples of the disclosure. The light guiding means101can be formed on a waveguide, an optical substrate, a transparent plate or any other suitable material.

In this example the light guiding means101comprises an exit pupil expander. The exit pupil expander is configured to increase the size of an exit pupil from a light engine or other optical arrangement. The light engine could be a display means such as a projection engine.

The in-coupling diffractive means103comprise any means that is configured to in-couple one or more beams of light from a light engine into the light guiding means101. The in-coupling diffractive means103is positioned within the light guiding means101so that, in use, the in-coupling diffractive means103can be positioned adjacent to the light engine.

The in-coupled beam of light travels through the light guiding means101via total internal reflection. The refractive index of the material that is used for the light guiding means101, the wavelength of the in-coupled beam, and the parameters of the in-coupling diffractive means103determine the total internal reflection angles.

The expanding means105is positioned within the light guiding means101so that the in-coupled beam of light is provided from the in-coupling diffractive means103to the expanding means105.

The expanding means105comprise any means that is configured to expand the in-coupled beam of light in at least one dimension. The expanding means105can comprise a diffractive means such as a diffraction grating or any other suitable means. In the diffraction grating the in-coupled beam of light is split into two with every internal reflection. The two split sections of the beam travel in different directions and continue splitting and so expand the exit pupil of the light engine. In the example shown inFIG.1the expanding means105has a grating which expands the beam in a horizontal direction.

The out-coupling diffractive means107is positioned within the light guiding means101so that the horizontally expanded beam of light is provided from the expanding means105to the out-coupling diffractive means107.

The out-coupling diffractive means107comprises any means that is configured to out-couple the horizontally expanded light beam out of the light guiding means. The out-coupling diffractive means107can function in a similar manner to the expanding means105so that the expanded beam of light is split into two with every internal reflection. The out-coupling diffractive means107can also be configured to expand the horizontally expanded beam of light in a second dimension. In the example shown inFIG.1the out-coupling diffractive means107has a horizontal grating which expands the horizontally expanded beam in the vertical direction.

The light guiding means101is configured so that the out-coupled expanded beam of light can be viewed by a user. The out-coupled expanded beams of light provide a virtual image that can be observed by a user. The out-coupled beam of light therefore provides an expanded exit pupil.

It is to be appreciated that the variations in the size, shape, position, and expansion direction of the different diffractive means are examples and that other variations could be used in other examples of the disclosure. For example, the expanding means105could expand the light beam in some other direction than horizontal. As another example, the out-coupling diffractive means107could expand the beam in some other direction than vertical. As a third example, the exit pupil of the beam of light in-coupled by the in-coupling diffractive means103would be expanded in the first expansion dimension already prior to in-coupling the beam into the light guiding means101. In this example there would be no expanding means105positioned within the light guiding means101.

The diffractive means that are used for the in-coupling diffractive means103, expanding means105, and out-coupling diffractive means107can comprise any means that can be configured to diffract the input beams of light. The diffractive means can comprise any one or more of a diffractive optical element, diffractive structure, diffraction gratings, holographic gratings, Bragg gratings, rulings, ridges, surface relief diffractive gratings or any suitable optical component or feature having a periodic structure that splits and diffracts light into several beams travelling in different directions.

FIG.2schematically shows a side view of an example apparatus201. The apparatus201comprises a light guiding means101and a control panel203. The apparatus201can comprise additional components that are not shown inFIG.2. For instance, the apparatus201could comprise a HUD, coatings to reduce reflections, and/or any other suitable components.

The control panel203can comprise a control panel for a vehicle or a cab of a vehicle. For instance, the control panel203could comprise the dashboard in car or other type of automobile. The control panel203could also comprise the control panel of an aircraft such as an aeroplane. In some examples the control panel203could be provided within a cab that can be attached to a vehicle or machinery. For instance, the control panel203could be provided within a cab that could be coupled to a digger or crane.

The control panel203can comprise any means that can be configured to provide information relating to the function of a vehicle associated with the control panel203. For instance, the control panel203could comprise one or more gauges or other means for displaying information. The information that is displayed by the control panel203could relate to the speed of the vehicle, a current operating mode of the vehicle, the location of the vehicle, a fuel status of the vehicle, information from a reversing camera or any other suitable type of information.

The light guiding means101could be as shown inFIG.1. The light guiding means101could comprise an exit pupil expander or any other suitable type of light guiding means101.

The light guiding means101could comprise an in-coupling diffractive means103, an expanding means105and an out-coupling diffractive means107. The in-coupling diffractive means103can be configured to in-couple one or more input beams of light into the light guiding means101from a first light engine. The expanding means105can be configured to expand the one or more input beams of light. The out-coupling diffractive means107can be configured to out-couple the one or more expanded beams of light from the light guiding means101.

In some examples the in-coupling diffractive means103, expanding means105and out-coupling diffractive means107can be arranged as shown inFIG.1. Other arrangements of the in-coupling diffractive means103, expanding means105and out-coupling diffractive means107could be used in other examples of the disclosure.

The light guiding means101and the control panel203can be integrated into a single apparatus201. The light guiding means101and the control panel203can be provided as a single unit.

The light guiding means101can be positioned within the apparatus201so that it overlays at least part of the control panel203. In some examples the light guiding means101could overlay all of the control panel203. In some examples the out-coupling diffractive means107of the light guiding means101could overlay all of the control panel203.

In some examples the light guiding means101can be positioned so that it is in contact with the surface of the control panel203. In such examples the light guiding means101can be provided directly overlaying the control panel203so that no gap is provided between the control panel203and the light guiding means101. In other examples a gap could be provided between the control panel203and the light guiding means101.

The light guiding means101can be transparent. The light guiding means101can be transparent so that the control panel203, or at least part of the control panel203can be viewed through the light guiding means101.

The light guiding means101is configured to display virtual images to a user of the control panel203. For instance, if the control panel203comprises the dashboard of a car the light guiding means101is configured to display virtual images to the driver.

The light guiding means101is configured so that the virtual images are displayed at a longer focal distance than the control panel203. For example the virtual images can be displayed at a longer focal distance than the distance to the control panel203and/or at a longer focal distance than images displayed on the control panel203. The control panel203is positioned at a given distance from a user. This may be within a short focal range. The virtual images that are displayed by the light guiding means101can be in a longer focal range. The virtual images that are displayed by the light guiding means101can be in a mid-range focal distance or in a long-range focal distance. In such examples the focal distance of the light guiding means101is set to a far or middle distance. For instance, a curved light guiding means101could be used or optical components such as lenses could be used to adjust the focal distance of a flat light guiding means101. In some examples the virtual images that are displayed by the light guiding means101can be focused at infinity. In such examples the focal distance of the at least one light guiding means101is set to infinity. For instance, a flat light guiding means101could be used.

In some examples focal distance of the virtual images that are displayed by the light guiding means101can be aligned with other objects that the user might be looking at. The aligning can be matching the focal distance or having the focal distances within a given range of each other. For example, if the user is also using a head up-display (HUD) the focal distance of the virtual images displayed by the light guiding means101could be matched to the focal distance of the HUD. In this example the HUD can have a fixed and known focal distance and so matching the focal distance of the images from the light guiding means101to the images in the HUD is possible.

In other examples the user could also be looking at objects around the vehicle. For instance, the user could be looking at a road and other vehicles and potential hazards on the road. In such examples it might not be feasible to align the focal distances of the virtual images and the potential hazards exactly. However, the focal distance of the virtual images from the light guiding means101could be provided within a threshold of the expected focal distance of such objects.

In some examples the light guiding means101can be configured so that the virtual images are only visible to the user of the control panel203. For instance, the virtual images could be displayed so that they can be viewed by the driver of a vehicle but not by any of the passengers in the vehicle. In some examples the exit pupil of the light guiding means101can be controlled so that the virtual images are only visible to the user of the control panel203.

The images provided by the light guiding means101can comprise any useful information for the driver or controller of the vehicle. The images provided by the light guiding means101can comprise information relating to the speed of the vehicle, a current operating mode of the vehicle, the location of the vehicle, a fuel status of the vehicle, information from a reversing camera or any other suitable type of information. The information that is displayed in the virtual images could comprise a subset of information that is displayed in the control panel203. In some examples the information that is displayed in the virtual images could comprise the most important or critical information for the user of the vehicle. The information that is displayed in the virtual images can be related to the environment or the objects around the vehicle.

In the example shown inFIG.2the apparatus101comprises a single light guiding means101. In other examples the apparatus101could comprise a plurality of light guiding means101. The plurality of light guiding means101could be arranged in a stacked configuration. The plurality of light guiding means101could be arranged in a stacked configuration overlaying the control panel203so that each of the light guiding means101within the stack, at least partially, overlays the control panel203. The plurality of light guiding means101could be arranged in a stacked configuration overlaying the control panel203so that each of the light guiding means101within the stack, at least partially, overlays each other. Other arrangements for the light guiding means101could be used in other examples of the disclosure.

In examples where the apparatus201comprises a plurality of light guiding means101the plurality of light guiding means101can be configured so that a first light guiding means provides a virtual image at a first focal distance and a second light guiding means provides a virtual image at a second focal distance. The images at different focal distances can be configured to provide volumetric images. Examples of volumetric images are shown inFIG.8.

In some examples volumetric images could be formed by the control panel203and one or more light guiding means101providing overlaying at least part of the control panel203. For instance, a first light guiding means101can be configured to provide a virtual image at a first focal distance and the control panel203can be configured to provide a real image at a second focal distance. The images at different focal distances can be configured to provide volumetric images

In examples where the apparatus201comprises a plurality of light guiding means101the plurality of light guiding means101can be configured to multiplex colours of the virtual images, to multiplex the focal distances of the virtual images, to control the field of view of the virtual images, to control parameters of the exit pupil or to control any other features.

The apparatus201can comprise additional components that are not shown inFIG.2. For instance, in some examples the apparatus201can comprise means for adjusting the focal distance of the virtual images provided by the apparatus201. In some examples the focal distance of the virtual images could be adjusted by adjusting the light guiding means101. In such examples one or more optical components could be provided and used to adjust the focal distance of the light guiding means101. The optical components could comprise one or more lenses or any other suitable components.

In some examples the focal distance of the virtual images could be adjusted by using different light guiding means101. For instance, the apparatus201could comprise a plurality of light guiding means101where different light guiding means101provide virtual images at different focal distances. The apparatus201could be configured to enable different light guiding means101to be selected as appropriate.

The different focal distances of the virtual images could be selected for any suitable reason. For instance, the different focal distances could be selected to account for users of different heights or to account for different HUDs or for any other suitable reason. In some examples the adjusting of the focal distance apparatus201could be manual. In such examples the adjusting of the focal distance could occur in response to one or more user inputs. In some examples the adjusting of the focal distance apparatus201could be automatic. In such examples the adjusting of the focal distance could occur without any specific user input. In such examples the adjusting of the focal distance could occur in response to an input other than a user input, such as the detection of the height of the driver.

FIG.3shows an example apparatus201in a vehicle301. In this example the apparatus201is provided within a car. In other examples the apparatus201could be used in other vehicles or aircraft or cabs for vehicles.

In the example ofFIG.3the apparatus201comprises a control panel203and a light guiding means101. The control panel203comprises the dashboard of the vehicle301in this example. The control panel203is provided behind a screen311. The screen can be configured to prevent glare and can be configured to protect the control panel203. The control panel203and the screen311are provided behind the steering wheel309of the vehicle301. The control panel203is positioned so that a driver305of the vehicle301can view the control panel203through the steering wheel309. The control panel203is positioned so that when a driver305is driving the vehicle301the control panel203is around 70-90 cm away.

The light guiding means101is positioned between the control panel203and the screen311. In the example ofFIG.3the light guiding means101can be positioned so that it is in contact with the surface of the control panel203. The light guiding means101is provided directly overlaying the control panel203so that only a very small gap or no gap is provided between the control panel203and the light guiding means101. In this example a larger gap is provided between the light guiding means101and the screen311.

The light guiding means101is coupled to a light engine307. The light engine307can comprise a projector or any other suitable means. The light engine can be configured to provide images to the in-coupling diffractive means103of the light guiding means101. The light engine307can be controlled to control the images that are displayed by the light guiding means101.

When the driver305is driving the vehicle301the driver305can look through the wind screen303at objects313that are positioned in front of the vehicle301. For instance, the driver305needs to be aware of what is on the road and any other hazards or objects313around the vehicle313. To view the objects313the driver305focuses their eyes to a focal point that is in a far range.

When the driver305wishes to view the control panel203the driver305has to look down at the control panel203. As the control panel203is positioned close to the driver305the driver305has to adjust the focus of their eyes to a near range.

In examples of the disclosure the addition of the light guiding means101to the control panel enables some information to be displayed at a different focal distance. For instance, the information displayed by the light guiding means101can be displayed with a focal distance corresponding to, or aligned with, the other objects313that the driver305might need to look at. The driver305can therefore view the information provided by the light guiding means101by keeping their eyes focused to a far range focal point.

The apparatus201therefore enables a driver305of a vehicle to easily view both objects313around the vehicle301and information displayed by the apparatus201without having to adjust the focus of their eyes. The adjusting of the focus of their eyes can take some time. This inherent latency can make it difficult for the driver305to interpret visual signals and can increase the risk of accidents occurring. Removing the need for making this adjustment can help therefore the driver305to identify hazards when they change between viewing the information form the apparatus201and viewing the environment around the vehicle301.

In some examples the light guiding means101can be configured so that the virtual images are only visible to the driver305of the vehicle. This can be achieved by controlling one or more parameters of the light guiding means101. The parameters of the light guiding means101that can be controlled could comprise the size and shape of the out-coupling diffractive means107or any other suitable parameters. The size and shape of the out-coupling diffractive means107can be designed so that the virtual images are positioned so that only the driver305of the vehicle301can view them. This can enable the light guiding means101to be used to display personal or private information.

FIGS.4A and4Bshow an example apparatus201in use. The apparatus201can comprise an apparatus201as shown inFIG.3in which a light guiding means101is provided overlaying a control panel203and configured to provide virtual images to the driver305. This example shows the apparatus201in use in a car. The apparatus201could be used in other types of vehicle.

FIG.4Ashows how the apparatus201appears when the driver305focusses their eyes to a near focal point.

In the example ofFIG.4Athe environment405around the vehicle301appears out of focus. The virtual images401displayed by the light guiding means101are also out of focus. The control panel203would be in focus. The control panel203could be viewed through the light guiding means101. In the example ofFIG.4Aan auxiliary control panel403is shown in focus. The auxiliary control panel403is provided to the side of the steering wheel309and can be configured to display navigation information or other suitable types of information.

FIG.4Bshows how the apparatus201appears when the driver305focusses their eyes to a far focal point.

In the example ofFIG.4Bthe environment405around the vehicle301appears in focus. The virtual images401displayed by the light guiding means101are also in focus. The control panel203and the auxiliary control panel403are out of focus.

Having both the virtual images401displayed by the light guiding means101and the environment405around the vehicle301in focus enables the driver305to switch between viewing the environment405and viewing the virtual images401displayed by the light guiding means101without having to refocus their eyes. This can reduce the risk of the driver305not noticing a hazard because they are focussed on the control panel203or because their eyes are still adjusting to look at the environment405.

FIG.5shows an example apparatus201in use. The apparatus201can be as shown inFIGS.3and4A and4Bor could be any other suitable type of apparatus201.

In the example ofFIG.5the light guiding means101is configured to display warning information in the virtual images401. The warning information could be displayed in response to a hazard501being detected. In this example the hazard501is an obstruction the road in front of the vehicle301. Other types of warning for other types of hazards could be provided in other examples.

In this example both the warning information displayed by the light guiding means101and the object501appear in focus at the same time. The focus distance of the warning information displayed by the light guiding means101can be aligned to be the same as or similar to the focus distance for the hazard object501. This can enable a driver305to easily switch between viewing the warning information and the hazard501. For instance, in some examples the distance between the hazard object501and the vehicle301can be estimated. The focal length of the virtual images displayed by the apparatus201can then be adjusted to be matched, or substantially matched, to the distance of the hazard object501. The focal length of the virtual images can be adjusted by uses of one or more optical components such as lenses or by selecting a light guiding means101from a stack of available light guiding means101or by any other suitable means.

FIGS.6A and6Bshow another example apparatus201in use. In this example the apparatus201comprises a HUD601in addition to the light guiding means101provided overlaying a control panel203. This example shows the apparatus201in use in a car. Other types of vehicles could be used in other examples.

The HUD601is displayed on the windscreen303in a location above the steering wheel309. The HUD601could be displayed in other locations in other examples of the disclosure.

The HUD601can be any suitable type of HUD601. The HUD601could be a projector HUD configured so that virtual images are projected from the windscreen. In some examples the HUD601could comprise one or more light guiding means101. The one or more light guiding means101could be as shown inFIG.1. The light guiding means101could be configured to display virtual images to the driver305. Other types of HUD601could be used in other examples of the disclosure.

FIG.6Ashows how the apparatus201and HUD601appear when the driver305focusses their eyes to a near focal point.

In the example ofFIG.6Athe environment405around the vehicle301and the virtual images401displayed by the light guiding means101are out of focus. The images displayed by the HUD601are also out of focus. In this example the control panel203could be viewed through the light guiding means101and would be in focus. The auxiliary control panel403provided to the side of the steering wheel309is also in focus.

FIG.6Bshows how the apparatus201and HUD601appear when the driver305focusses their eyes to a far focal point.

In the example ofFIG.6Bthe environment405around the vehicle301and the virtual images401displayed by the light guiding means101appear in focus. The images displayed by the HUD601also appear to be in focus. The control panel203and the auxiliary control panel403are out of focus.

In this example the focal distance of the light guiding means101overlaying the control panel203can be aligned to the focal distance of the HUD601. The focal distance of the light guiding means101can be the focal distance of the virtual images displayed by the light guiding means101. In some examples the focal distance can be matched to the focal distance of the HUD601. In other examples the focal distance can be aligned so that it is similar to the focal distance of the HUD601or within a predefined threshold of the focal distance of the HUD601.

Having the virtual images401displayed by the light guiding means101aligned to the focal distance of the HUD601enables the driver305to switch between viewing the environment405and viewing the virtual images401displayed by the light guiding means101and also the HUD601without having to refocus their eyes. This can reduce the risk of the driver305not noticing a hazard or critical information displayed on the HUD601because they are focussed on the control panel203or because their eyes are still adjusting to look at the environment405or HUD601.

FIGS.7A and7Bshow another example apparatus201in use. In this example the apparatus201comprises also HUD601in addition to the light guiding means101provided overlaying a control panel203. This example apparatus201can be the same as the apparatus201shown inFIGS.6A and6B.

In the example ofFIGS.7A and7Bthe apparatus201is in use in a car. Other types of vehicles could be used in other examples.

In the example ofFIGS.7A and7Bthe visibility conditions for the HUD601are poor. The visibility of HUD601can be affected by bright lights or any other suitable factor. In the example ofFIGS.7A and7Bthe visibility of the HUD601is reduced due to bright sunlight701. Other sources of bright light could be the headlights of oncoming vehicles or any other suitable source. Other examples of poor visibility conditions for the HUD601could include unwanted diffraction effects propagating towards the driver305, caused by the bright lights on the diffraction gratings off the light guiding means101.

FIG.7Ashows how the apparatus201and HUD601appear when the driver305focusses their eyes to a near focal point.

In the example ofFIG.7Athe environment405around the vehicle301and the virtual images401displayed by the light guiding means101are out of focus. The images displayed by the HUD601are also out of focus. In this example the control panel203could be viewed through the light guiding means101and would be in focus. The auxiliary control panel403provided to the side of the steering wheel309is also in focus.

FIG.7Bshows how the apparatus201and HUD601appear when the driver305focusses their eyes to a far focal point.

In the example ofFIG.7Bthe environment405around the vehicle301appear in focus. The images displayed by the HUD601also appear to be in focus however they appear to be washed out due to the bright light from the sun701. The virtual images401displayed by the light guiding means101appear in focus. These images are not washed out because they are positioned out of the direct path of the bright sunlight.

The control panel203and the auxiliary control panel403are out of focus.

In this example the light guiding means101supports the HUD601as the information displayed by the light guiding means101is still visible, and at a similar focal distance, even when the HUD601appears to be washed out. This can enable the light guiding means101to be used as a back-up for the HUD601. The information displayed on the light guiding means101can be the same as the information displayed on the HUD601or can comprise at least some of the same information as is displayed on the HUD601. This enables the information to always be available to the driver305at a long-range or mid-range focal distance, even during poor visibility conditions for the HUD601.

FIGS.8A and8Bshow volumetric images that can be displayed by the apparatus201in some examples of the disclosure. In this example the apparatus201comprises a control panel203and a light guiding means101. In other examples the volumetric images could be displayed by a plurality of light guiding means101.

The control panel203provides a first image image801A at a first focal distance and the light guiding means101provides a second virtual image801B at a second focal distance. In this example the first focal distance is longer than the second focal distance so that the first image801A appears to be further away than the second virtual image801B.

FIG.8Aschematically shows the control panel203and the light guiding means101and the respective images801A and801B. In this example the first image801A comprises a rear section of a cube and the second virtual image801B comprises a front section of a cube.

FIG.8Bshows how the two images801A and801B would appear to the user. The light guiding means101and the control panel203can be configured so that the images801A and801B appear to be volumetric or three dimensional or include a depth effect. In the example ofFIG.8Bthe light guiding means101and the control panel203are configured so that the two images801A and801B are aligned to provide combined image803. In this example the combined image803comprises a cube that appears three dimensional to the user.

In the examples ofFIGS.8A and8Bthe combined image803comprises a cube. Other types of image could be provided to a user in other examples of the disclosure. For example, the combined virtual image could comprise warning information about hazards or any other suitable information.

Other arrangements of the virtual images could be used in other examples of the disclosure. For instance, the apparatus201could be configured so that the light guiding means101is configured to display a first image for a user's first eye and a second image for a user's second eye. In some examples the apparatus201can comprise a plurality of different light guiding means101and these can be configured so that different images for the different eyes can be displayed by the different light guiding means101. This can enable binocular or stereoscopic images to be provided by the apparatus201.

Variations and modifications can be made to the examples shown in the Figs. And described above. For instance, in some examples the apparatus201can be configured to enable the position of the exit pupil of the apparatus201to be adjusted. The exit pupil of the apparatus201can be adjusted to account for the height or position of the driver305or for any other suitable purpose. The adjustment could be a mechanical adjustment. For example, the apparatus201or parts of the apparatus201could be tilted or otherwise moved so as to adjust the position of the exit pupil. The light engine307or the light guiding means101or any other suitable parts of the apparatus201can be moveable so as to enable the position of the exit pupil to be adjusted.

The moveable parts of the apparatus201can be configured to allow for manual adjustment of the position of the exit pupil. In some examples the moveable parts of the apparatus201can be configured to be adjusted to correspond to a position of the HUD601or any other suitable parts of the vehicle or apparatus201. For instance, if a user adjusts the position of the HUD601a corresponding adjustment to the position of the exit pupil of the apparatus201could be made automatically without any further user input.

Examples of the disclosure therefore provide an apparatus201for blending virtual and real images. The virtual images can be configured to have a focal distance that is aligned with the real images. This can enable a user to easily switch between viewing the virtual images and viewing the real images. This can be useful for drivers of vehicles where the driver should be constantly aware both of potential hazards in their environment and also information being displayed on a control panel203.