WO2020174224A1

WO2020174224A1 - Apparatus for selectively illuminating a target field, for example, in a self dimming headlight system

Info

Publication number: WO2020174224A1
Application number: PCT/GB2020/050431
Authority: WO
Inventors: Neil Richard Haigh
Original assignee: Colordyne Limited
Priority date: 2019-02-27
Filing date: 2020-02-24
Publication date: 2020-09-03
Also published as: GB201902668D0

Abstract

A light emitting and detecting apparatus comprising a catadiptric lens body containing an integral reflector within a spherical lens and defining first and second conjugate focal planes at which a light emitting array and a light detector are arranged to emit and detect light incident on a target field along a common axis. A controller processes an image received from the detector to determine whether a predefined element is contained in the target field and selectively adapts the output of a subset of the light emitting elements of the array to modify the illumination of the corresponding region of the target field.

Description

Apparatus for selectively illuminating a target field, for example, in a self dimming headlight system.

This invention relates to self dimming headlights and other apparatus for selectively illuminating a target field.

Vehicle headlights may be arranged to detect an oncoming vehicle and to selectively reduce the intensity of illumination of a portion of the target field so as to avoid dazzling the oncoming driver. However, the possibilities for adjustment may be limited.

It is a general object of the present invention to provide an apparatus that can provide selective adjustment of the illumination over a target field.

In accordance with the present invention there is provided an apparatus for emitting and detecting light travelling along a first axis, including a lens body, a controller, and first and second light handling units.

The lens body includes a ball and a reflector contained within the ball. The ball is transparent and has a surface, the surface defining a total surface area of the ball and having substantially spherical curvature over substantially all of the total surface area.

A reflector plane is defined as a nominal plane passing centrally through the ball and normal to the first axis. When the reflector is considered as projected along the first axis onto the reflector plane, the reflector occupies less than all of an area of the reflector plane bounded by the surface.

The apparatus is arranged to define first and second conjugate focal planes relative to a subject plane, and to transmit light entering or leaving the lens body along the first axis and travelling between the lens body and the subject plane, such that: a first portion of the light travels through the ball and past the reflector between the subject plane and the first light handling unit located at the first conjugate focal plane, and a second portion of the light travels through the ball and is reflected from the reflector between the subject plane and the second light handling unit located at the second conjugate focal plane. A respective one of the first and second light handling units includes a light emitter, and the respective other one of the first and second light handling units includes a light detector. The light emitter comprises an array of light emitting elements, each of the light emitting elements being individually controllable by the controller.

The apparatus is arranged to project light emitted from the array along the first axis to illuminate a target field of the subject plane, such that the light emitted from each of the light emitting elements illuminates less than ail of the target field.

The detector is arranged to generate a signal representing an image of the target field.

The controller is arranged: to receive the signal from the detector; to process the signal to identify whether a predefined element is present in the image; and then, responsive to identifying the predefined element, to identify a subset of the light emitting elements from which light is emitted and projected onto a region of the target field containing said predefined eiement,and to selectively adjust the light emitting elements to obtain a different light output condition of the light emitting elements contained in the subset relative to the light emitting elements not contained in the subset.

The arrangement of the reflector in the ball enables two beam paths to be combined together and accurately aligned on a common axis, while the conjugate focussing properties of the ball allow the individual emitters of the array to be mapped to individual regions of the sensed field of illumination, so that the illumination of multiple regions of the field can be more selectively adjusted responsive to identifying one or more predefined elements in those regions.

Further advantageously, the apparatus allows the reflected beam to transmit light to the field from the second light handling unit substantially without loss, while the beam travelling to or from the first light handling unit remains substantially unobstructed with very little loss. The apparatus can thus be used for higher power lighting applications such as vehicle headlamp systems where energy efficiency is an important consideration. Further features and advantages of the invention will be appreciated from the various illustrative embodiments which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which:

Fig. 1 shows an apparatus in accordance with an embodiment of the invention in a first configuration, in whic h the lens body transmits light past the reflector to or from the first light handling unit;

Fig. 2 shows the apparatus in a second, alternative configuration wherein the lens body transmits light through an aperture in the reflector to or from the first light handling unit;

Fig. 3 shows how the reflector is projected along the first axis onto the nominal reflector plane P1 to determine its projected area in the reflector plane;

Fig. 4 shows the apparatus in the first configuration, looking in the direction of the arrows IV - IV along the first axis X1 towards the reflector plane P1 as shown in Fig. 1;

Fig. 5 shows the apparatus in the first configuration, looking in the direction of the arrows V - V towards the plane P2 containing the surface of the reflector;

Fig. 6 shows the apparatus in the second configuration, looking in the direction of the arrows Vi - VI along the first axis X1 towards the reflector plane P1 as shown in Fig. 2;

Fig. 7 shows the apparatus in the second configuration, looking in the direction of the arrows VII - V!i towards the plane P2 containing the surface of the reflector;

Fig. 8 shows the apparatus in an embodiment including a user interface and a beam director;

Fig. 9 shows one of the light handling units;

Fig. 10 shows one of the light handling units comprising an array;

Fig. 11 shows one element of the array comprising a sub-array;

Fig. 12 illustrates one mounting configuration of the apparatus, referred to hereinafter as "mounting configuration A1", in which both light handling units are arranged in fixed relation to the lens body;

Fig. 13 and 14 illustrate another mounting configuration of the apparatus, referred to hereinafter as "mounting configuration A2", in which both light handling units are arranged in fixed relation to the lens body;

Fig. 15 illustrates another mounting configuration of the apparatus, referred to hereinafter as "mounting configuration B1", in which the second light handling unit is arranged in fixed relation to the lens body, and is rotatable together with the lens body relative to the first light handling unit;

Fig. 16 illustrates another mounting configuration of the apparatus, referred to hereinafter as "mounting configuration C", In which the lens body is rotatable relative to both of the first and second light handling units;

Fig. 17 illustrates one of the light handling units configured as an array in which each light detecting or emitting element is coupled to the respective conjugate focal plane by a respective waveguide;

Fig. 18 shows an embodiment in which the second light handling unit includes the light emitter and the first light handling unit includes the light detector, both the emitter and the detector being configured as an array;

Fig. 19 shows as variant of the embodiment of Fig. 18 wherein the reflector surrounds an apeture, corresponding to the second configuration of Figs. 2, 6 and 7;

Fig. 20 shows an image of the target field in an embodiment configured for forward lighting in a motor vehicle, and

Fig. 21 shows the image of Fig. 20 wherein a subset of the light emitting elements are selectively extinguished.

Reference numerals occurring in more than one of the figures indicate the same or

corresponding elements in each of them. in this specification, light means electromagnetic radiation of any frequency, whether visible or non-visibie, that can be focused by the lens body.

The reflector plane is a nominal flat plane.

A beam director means any element of the apparatus capable of moving or directing a beam of the light or the respective, first or second portion of the light with respect to the subject plane or the first or second light handling unit. A beam director may include an actuator (which can be any mechanism for moving a mechanical part, for example, a motorised drive unit) which is arranged to rotate or otherwise move an optical element of the apparatus. The optical element may be the lens body, the first or second light handling unit, or a first, second or third optical element (for example, a reflector, a lens or a refractor) located in the path of the light respectively between the lens body and the first light handling unit, between the lens body and the second light handling unit, or on the first axis between the lens body and the subject plane, or any combination of two or more of those components.

A scanning light detector means a detector for detecting light from a small region of the subject plane, generally referred to herein as a point or pixel, without differentiating between different spatial parts of the small region. Thus, the signal generated from a scanning light detector may define one or more parameters, such as illuminance, of a single point or pixel of an image generated from the signal. By scanning the target point over the subject plane many such points or pixels can be arranged in a spatial array to form the image.

An image may be any representation or data set that is displayed or is capable of being displayed as a spatial array. For example, light received from the subject plane may be displayed as an image comprising a two-dimensional or three-dimensional or quasi-three-dimensionai visible picture of a target object or region in the subject plane, and an image may be projected onto the subject plane to form a visible projection of an object in an object plane located at the respective, first or second conjugate focal plane, wherein the object may be a static picture or slide, a drawing, or a moving image.

An optical element means any element of the optical system that reflects or refracts or otherwise transmits the light, including for example the lens body and any additional reflectors or lenses or waveguide elements.

Referring to Figs. 1 and 2, the apparatus includes a lens body 1, a first light handling unit 10, and a second light handling unit 20, and is arranged to define first and second conjugate focal planes F1, F2 relative to a subject plane F3.

The first light handling unit 10 is located at the first conjugate focal plane F1, and the second light handling unit 20 is located at the second conjugate focal plane F2.

In this specification, the subject plane means a nominal plane, which may iie at a finite distance or an infinite distance or within a range of distance from the lens body, at which distance or within which range of distance the light received from or projected onto a subject surface or body can be focused to project an image of the subject onto the conjugate focal planes, or to project an image from the conjugate focal planes onto the subject plane. Said distance or range of distance is defined by the conjugate focal distance of the subject plane relative to the first and second conjugate focal planes. References to scanning a region of the subject plane or moving the target point or the light emitted from the lens body across the subject plane should be construed accordingly to include scanning or moving the light across a subject or target surface or body, which may be flat or may have depth in the direction of the light beam depending on the conjugate focal distance.

The first and second conjugate focal planes are defined by their optical relationship to the subject plane as defined by the optical characteristics of the lens body and any other optical elements of the system, and not by their straight line distance from the lens body. So for example, the straight Sine distance between the lens body and the first or second light handling unit located at the corresponding conjugate focal plane may be reduced or extended by another optica! element such as a reflector or refractor or focussing arrangement interposed between the iens body and the first or second light handling unit.

The lens body 1 includes a ball 2 and a reflector 4 contained within the ball 2. The ball 2 is transparent and has a surface 3, the surface 3 defining a total surface area of the ball 2 and having substantially spherical curvature over substantially all of the total surface area.

The lens body and the first and second light handling units form a catadioptric conjugate imaging system, which is to say, an optical system in which a reflector and a lens are combined to define a focal relationship between the subject plane F3 and the first and second conjugate focal planes F1, F2.

Those skilled in the art will appreciate that a catadioptric system may be arranged so that the field of view remains entirely visible as light is refracted past (around or through) the reflector, despite the fact that the reflector is positioned on the axis of the optical system. This may be achieved by positioning the reflector at a position other than a "field stop" location, for example, at an "aperture stop'location, so that the normal rules of conjugate imaging apply. The transparent ball functions as a biconvex lens or "thick" lens . The curvature of the surface of the bail and its refractive index effectively define the focal length of the "thick" lens and thereby its conjugate imaging properties. Typically for example, for an acrylic ball of diameter 70 mm and refractive index n = 1.5, the back vertex focal length of the lens is of the order of 17 mm or so. Those skilled in the art will readily select the materials and dimensional parameters to suit applications involving near or distant target planes.

In this specification, a ball as included in the iens body means a spherical or spheroidal or aspherical body that functions as a lens with conjugate imaging properties. That is to say, the optical characteristics of the ball including its surface (which may be polished) are suitable for focusing the light transmitted by the bail between the conjugate focal planes F1, F2 and the subject plane F3. For example, if the light travels from the subject plane F3 to the conjugate focal planes F1, F2 then the ball 2 will focus the light to form an image at the conjugal focal planes F1, F2.

Spherical curvature means the curvature of a sphere.

Substantially spherical curvature means a spherical curvature that is modified to a degree that allows the ball 2 to function as a lens with conjugate imaging properties, and in particular, to a degree necessary to reduce spherical aberration. Thus, the ball 2 may be a sphere or may be a spheroid or asphere, for example, an oblate or prolate sphere, with its surface curvature selected to minimise spherical aberration.

The ball may be made from a solid material such as glass or a transparent plastic such as acrylic.

In order to reduce spherical aberration the bail may comprise a plurality of concentric spherical shells, each shell having a different refractive index from the other shells. The refractive index of the shells relative to each other may vary progressively inwardly from the outer surface 3 of the ball towards its centre. For example, the refractive index of each shell (other than the outermost shell) may be greater than that of the immediately radially outwardly adjacent shell, which is to say, the refractive index of the shells increases progressively inwardly towards the centre of the ball 2. In alternative embodiments the ball may comprise a transparent shell containing a transparent liquid or gel.

The reflector may be for example, a mirrored solid body, a mirrored internal surface of the ball, or a reflective surface of an optical discontinuity such as a void space within the ball.

The reflector may be arranged in fixed relation to the ball, as shown in the illustrated embodiments. In alternative embodiments (not shown), the reflector may be rotatable or otherwise movable within the ball and relative to the ball.

The apparatus Is arranged to emit or detect light travelling along a first axis X1, which may be defined in a reference position, which may be a default or rest position of the lens body as shown for example in Figs, 1 and 2. It will be understood that where the lens body or reflector is movable relative to the first and/or second light handling unit, the two light handling units may emit or receive Sight along different axes depending on the relative position of the respective components, but will emit or receive light along the common, first axis X1 in their reference position. Thus, embodiments may allow one beam axis to move angularly around the other to scan a region of the subject plane, when the two beams are directed to or from the two respective light handling units, as further explained below.

The first axis X1 may pass through the geometric centre of the ball, which may be the centre of rotation about which the lens body or reflector rotates, as shown in each of the illustrated embodiments.

Referring also to Fig. 3, a reflector plane P1 is defined as a nominal plane passing centrally through the ball 2 and normal to the first axis X1. The reflector 4 may be considered as projected along the first axis X1 onto the reflector plane P1, as shown in Fig. 3. The area A1 of the reflector plane P1 occupied by the reflector 4 when so projected is less than all of the area A2 of the reflector plane P1 bounded by the surface 3 of the ball 2, as can be seen in each of Figs. 4 - 7.

The reflector plane P1 passes centrally through the ball 2, so that where the ball 2 is spherical (as shown), the reflector plane P1 will be an equatorial plane bisecting the ball 2. The reflector is preferably 100% reflective, but could be less than 100% reflective.

As illustrated, the reflector 4 may be located centrally within the ball 2, and may be circular.

The reflector may be flat or curved, and may lie in (or, if curved, may define a central axis of symmetry normal to) a plane P2 which intersects the nominal reflector plane P1.

In all of the illustrated embodiments, the reflector 4 is flat and circular and lies in a plane P2 which intersects the nominal reflector plane P1.

Referring to Figs. 1, 4 and 5, in a first configuration (and as also illustrated in all of the embodiments apart from Figs. 2, 6 and 7 and Fig. 19), when the reflector 4 is considered as projected along the first axis X1 onto the reflector plane P1, the reflector 4 is spaced apart from the surface 3 of the ball 2 by a gap 5, the gap 5 surrounding the reflector 4,

Referring to Figs. 2, 6 and 7, in a second configuration the reflector surrounds an aperture 6, the aperture passing through the reflector. The first axis X1 may pass centrally through the aperture, as shown (in Fig. 2 the reflector is shown edge-on and schematically, and for clarity, the portion of the reflector lying in front and behind the aperture 6 from the direction of view is not shown, but it will be understood that the reflector is annular, as shown in Figs. 6 and 7.)

Referring also to Figs. 18 and 19, the apparatus is arranged to transmit light entering or leaving the lens body 1 along the first axis X1 and travelling between the lens body 1 and the subject plane F3, such that a first portion L1 of the light travels through the ball 2 and past the reflector 4 between the subject plane F3 and the first light handling unit 10 (located at the first conjugate focal plane F1), and a second portion L2 of the light travels through the ball 2 and is reflected from the reflector 4 between the subject plane F3 and the second light handling unit 20 (located at the second conjugate focal plane F2).

In the first configuration (Figs. 1, 4 and 5) the first portion of the light L1 travels around the reflector 4 through the gap 5, while in the second configuration (Figs. 2, 6 and 7), the first portion of the light L1 travels through the aperture 6. The first or second configuration may be adopted in any embodiment of the invention.

The first portion L1 of the light may travel between the lens body 1 and the first light handling unit 10, either directly or via additional optical elements.

The second portion L2 of the light may travel between the lens body 1 and the second light handling unit 20, either directly or via additional optical elements. The first and second portions L1, L2 of the light may travel between the lens body 1 and the subject plane F3, either directly or via additional optical elements.

Additional optical elements (not shown) may be provided to adjust focus and/or to correct spherical aberration or for other purposes. The or each additional optical element may include, for example, a focusing element, e.g. a distance adjustment mechanism or an adjustable lens, .e.g. a liquid or tuneable lens, or a distortion or correction plate, a lens or a reflector or a refractor or a filter, or an object display for displaying an image or graphic object to be projected onto the subject plane. In each embodiment of the invention, a respective one of the first and second light handling units includes a light emitter, which comprises an array of light emitting elements, and the respective other one of the first and second light handling units includes a light detector.

In a first possible arrangement, the first light handling unit 10 may include the light detector, while the second light handling unit 20 includes the light emitter comprising the array 30, as shown in the example of Figs. 18 and 19. In such configurations the emitted light beam is reflected from the reflector 4 substantially without loss.

Alternatively, in a second possible arrangement, the second light handling unit 20 may include the light detector, while the first light handling unit 10 includes the light emitter comprising the array 30. The first and second possible arrangements may be used alternatively in each embodiment of the invention. Although the second possible arrangement is not illustrated, it may correspond to the arrangement of Figs. 18 and 19 wherein the direction of the light rays is reversed from that indicated by the arrows.

Referring to Fig. 8 and Fig. 9, each of the light handling units may comprise two or more functional units, which may be light emitters or light detectors, wherein one of the functional elements in one of the light handling units is the light emitting array, and one of the functional elements in the other one of the light handling units is a light detector for generating an image of the target field.

For example, each light handling unit 10, 20 may include two light emitters 11 or 21 or two light detectors 12 or 22 or a light emitter 11 or 21 and a light detector 12 or 22.

As long as one of the light emitters is an array of light emitting elements, each of the other light emittesr and/or each of the light detector may be either an array 30 of light emitting or detecting elements 31 or a scanning light emitter or detector for emitting or detecting light onto or from a target point on the subject plane F3, or different ones of the other light emitters and/or light detectors may be respectively an array and a scanning emitter or detector.

The or each light emitter (including the essential light emitting array) and they or each light detector (including the essential light detector for generating an image) may be arranged to emit and detect visible or non-visible light in the same frequency range or in different frequency ranges. For example, they may emit and detect visible light, or infra-red light, or the emitter may emit visible light and the detector may detect non-visble light, or vice versa.

Where the respective, first or second light handling unit includes two or more functional units such as a light emitter and a light detector (or two or more light emitters or detectors), the functional units may be arranged concentrically with an outer unit 10', 20' (light emitter or light detector) surrounding an inner unit 10", 20" (light emitter or light detector) when considered in a direction along the emission axis, as shown in Fig, 9. Irrespective of how many functional units are combined in each light handling unit, each functional unit (light emitter or light detector) may be configured as a light emitting or detecting array, or to emit or detect iight along a single axis, as long as the essential light emitting array is present.

As shown in Fig. 8, the apparatus may further include a user interface 60. The controller may include a processor 51 and memory 52 and may send and/or receive signals to and from the light emitter(s) and/or detector(s) of each Iight handling unit 10, 20 and the user interface 60. Where a beam director 70, e.g. an actuator 71 is provided for directing the Iight or target point over the subject plane F3, the controller 50 may also control the beam director 70 as further explained below. The user Interface may include controls for issuing commands to control elements of the apparatus such as the Iight handing units and/or the beam director, and/or indicating means for conveying information from those elements of the apparatus to the user, and will vary according to the intended application. In some applications the user interface may include for example a display screen and/or a keyboard and/or a mouse (not shown), while in other applications the interface may include a head-up display in a vehicle (not shown).

Referring to Fig. 10, a Iight emitting or detecting array 30 forming a functional unit of a respective Iight emitter or Iight detector 10, 20 comprises an array of light emitting or light detecting elements 31. If the elements 31 are light detecting elements then they may detect an image projected onto the array from the subject plane F3 to generate a signal to the controller 50. If the elements 31 are Iight emitting elements then they may generate an image responsive to a signal from the controller 50 and/or user interface 60 which is projected onto the subject plane F3.

Referring to Fig. 17, where the array 30 is configured as the (or a) light emitter, each of the iight emitting elements 31 may be provided with a respective waveguide 120, the waveguide being arranged to transmit iight from the respective light emitting element 31 to the respective conjugate focal plane F1 or F2.

Referring to Fig. 11, each element 31 may comprise a sub-array of sub-elements 31' which are individually controllable by the signals. For example, where the array 30 is a Iight emitting array, the sub-elements 31' may be selectively controllable to emit Iight at different frequencies. For example, the sub-elements 31' might be LEDs emitting light at different frequencies. Where the array 30 is a light detecting array, the sub-elements 31' might be detectors for detecting light at different frequencies to send a signal Indicating more than one image, the images being superimposed, each image representing the light emitted from the subject plane F3 at a different one of those frequencies.

The apparatus may be arranged with the first and second light handling units in fixed relation to the lens body. Optionally in such arrangements, the entire apparatus including the first and second Sight handling units and the lens body may be either fixedly or adjustably mounted to a support, for example, the body or chassis of a vehicle.

Referring nowto Figs. 12 - 16, the apparatus may include a beam director 70 which is operable (e.g. by the controller 50 and/or responsive to user commands via the user interface 60) to rotate at least one optical element of the apparatus relative to the subject plane F3 to move at least one of the first and second portions of light L1, L2, or to move a target point T1 (Fig. 18,

Fig. 19) from which at least one of the first and second portions L1, L2 of light is received, across the subject plane F3.

The at least one optica! element of the apparatus may be at least one of the lens body 1, the first light handling unit 10, the second light handling unit 20, a first additional optical element interposed between the first light handiing unit 10 and the lens body 1, a second additional optica! element interposed between the second light handling unit 20 and the lens body 1, and a third additional optical element interposed between the lens body 1 and the subject plane F3.

The beam director 70 may include an actuator 71 for moving the lens body 1, e.g. in rotation, preferably about its central point. For this purpose the lens body 1 may be movably, e.g.

rotatably mounted in any convenient manner, for example, slidably supported on a surface such as a circular or cylindrical frame, or, as illustrated, in gimbals 80 for rotation about one, two or three axes as required.

As illustrated, the reflector 4 may be arranged in fixed relation to the ball, and the beam director 70 may include an actuator 71 operable to move, preferably to rotate, the lens body 1 (including the reflector 4) relative to the subject plane F3. Alternatively, if the reflector 4 is movabie relative to the ball 2, then the beam director 70 may be operable to move the reflector 4, preferably in rotation, relative tothe ball 2. In this case the arrangements illustrated in Figs. 12 - 16 and discussed below may be adapted mutatis mutandis.

The beam director 70 may include a first actuator 71' for moving the light or target point to a desired region of the subject plane F3, and a second actuator 71" for scanning the light or target point rapidly over the desired region. The or each actuator may include several actuator units. As shown in Figs. 12, 13 and 14, the first and second light handling units 10, 20 may be arranged in fixed relation to the lens body 1, and the actuator 71 operable to rotate the lens body 1 together with the first and second light handling units 10, 20 relative to the subject plane.

Where both of the first and second light handling units 10, 20 are fixed in relation to the reflector and the lens body 1, the first axis X1 may be defined in a fixed position relative to the reflector, in which case both units 10, 20 will receive or emit light traveiling along the first axis X1 in all rotational positions of the lens body 1.

In mounting configuration A1 as shown in Fig. 12, a single actuator 71 is arranged to perform both rapid scanning and scan area selection functions. in mounting configuration A2 as illustrated in Figs. 13 and 14, separate actuators 71', 71" are provided for those two functions. Referring to Fig 15, alternatively a respective one of the first and second light handling units 10, 20 may be arranged in fixed relation to the lens body 1, the actuator 71 or second actuator 71" being operable to rotate the lens body 1 together with said respective one of the first and second light handling units 10, 20 relative to the subject plane F3 and relative to the respective, other one of the first and second light handling units 10, 20. The second actuator 71" may accomplish this movement for example to scan the subject plane F3.

In such arrangements, the lens body 1 and both of the first and second light handling units 10,

20 may be movabie, e.g. rotatable, relative to the subject plane F3 by the actuator 71 or first actuator 71', as illustrated in Fig, 15, so as to move the scanned region to a desired part of the subject plane F3.

Thus, motion of 1, 10 and 20 together may be accomplished independently of motion of 1 and 20 relative to 10 in mounting configuration B1, or in the alternative mounting configuration B2 discussed below, independently of motion of 1 and 10 relative to 20.

In mounting configuration B1 as shown in Fig. 15, the second light handling unit 20 is arranged in fixed relation to the lens body 1, and is rotatable by the actuator 71" together with the lens body 1 relative to the first light handling unit 20.

Alternatively, in a similar mounting configuration B2 (not shown), the first light handling unit 10 is arranged in fixed relation to the lens body 1, and is rotatable together with the lens body 1 relative to the second light handling unit 20. The apparatus may be mounted on gimbals 80 and movable by the actuator 71 in a similar arrangement to that of Fig. 15 with the gimbai frames adapted to support 10 and 20 in the required manner.

Referring to Fig. 16, in alternative mounting configuration C the actuator 70 may be operable to rotate the lens body 1 relative to both of the first and second light handling units 10, 20. Again, a first actuator 7G and second actuator 71" may be provided respectively for aiming and scanning the beam or target point over the target surface.

It should be understood that references herein to the different mounting configurations ( A1,

A2, B1, B2, C) refer broadly to the relationship of movement between the first and second light handling units 10, 20 and the reflector 4 and/or lens body 1 and not to the details of the gimbals or other mechanical mounting arrangements which can be adapted by the skilled person as required.

Although specific mounting and rotation arrangements are further discussed below, it should be understood that in each of its embodiments as discussed herein, the apparatus may be mounted in accordance with any of the above mentioned arrangements including in a fixed position or in any of mounting configurations A1, A2, B1, B2, C. Referring now to Figs. 18 - 21, for simplicity only a small number of the light emitting elements 31 of the light emitting array forming part of the second! Sight handling unit 20 are shown and are identified respectively as A, B, C, D and E. In the illustrated example the light detector forms part of the first light handling unit 10 and is also configured as an array 30 of light detecting elements 31, of which again only a few are shown and are identified respectively as A", B", C", D" and E”.

Each of the light emitting elements 31 of the array forming the light emitter is individually controllable by the controller 50, which is to say, the controller can modify the output of the individual element relative to that of the other elements, for example, by switching it on or off, or by changing the intensity or wavelength of the light output from that element 31.

The coaxial, conjugate imaging and focusing properties of the lens body allow the respective emitting elements A, B, C, D and E to be mapped to their respective counterpart detecting elements A", B", C", D" and E" and pixels or regions A', B', C', D' and E' of the target surface at the subject plane F3, so that the controller 50 is able to identify a subset of the light emitting elements A, B, C, D and E corresponding to an identified subset of the target pixels or regions A', B', C', D', E' of the target field and light detecting elements A", B", C", D" and E", as shown by the indicated ray traces of which only a few are shown for clarity. Those skilled in the art will understand where the other ones go.

Such mapping could be stored in the memory of the controller 50 or could be done Iteratively by detecting a pattern projected onto the target surface, or could be achieved (e.g. by an algorithm, or heuristica!ly) by the controller selectively modifying the light output of the individual emitting elements until the modification of the identified subset is detected by the light detector.

As shown, the apparatus is arranged to project light emitted from the array 30 along the first axis X1 to illuminate a target field of the subject plane F3 (corresponding to the image 101').

The light emitted from each of the light emitting elements 31 illuminates less than all of the target field; which is to say, the light from each element 31 falls on a corresponding region or pixel of the target field at the subject plane F3 that is less than the whole of the target field, while the whole array illuminates the whole of the target field.

Each element 31 will illuminate a region of the target field different from that illuminated by the other elements 31 of the light emitting array - which is to say, a region that may overlap with the regions illuminated by the other elements 31 but which is not perfectly conterminous with those other regions.

The pixels or regions of the target field are shown as squares in the image 101' as shown in Figs. 20 and 21 and a few of them are indicated by the same iettters A', B', C, D', E' as the corresponding regions as shown in Figs, 18 and 19,

The detector (corresponding to the first iight handiing unit 10 in the illustrated example) is arranged to generate a signal S1 representing an image 101' of the target field, which is illustrated graphically in Figs, 20 and 21 and which could be displayed the same way on a display of the user interface 60, for example, on a screen or a head-up display.

The controller 50 is arranged to receive the signal S1 from the detector 10 and to process the signalSl to identify whether a predefined element is present in the image

The predefined element might be for example a pedestrian 130 or part of a pedestrian, or a vehicle 140 or part of a vehicle, as shown in the illustrated example, or any other identifiable object or shape, e.g. a weapon or the outline of a specific vehicle such as a ship or an aircraft, or a type of animal. Thus, the controller may be programmed with image processing software as known in the art to recognise such elements depending on the required application.

The controller 50 is further arranged, responsive to identifying the predefined element 130,

140, to identify a subset of the Iight emitting elements from which Iight is emitted and projected onto a region of the target field containing the or each predefined element 130, 140, and to selectively adjust the Iight emitting eiementsB1 of the array 30 to obtain a different Iight output condition of the light emitting elements 31 contained In the subset relative to the Iight emitting elements not contained in the subset. In the illustrated example, the controller 50 has identified the head region of the pedestrian 130 whieih is contained in pixel C' of the Image 101', and the region of the vehicle 140 in which the driver is seated and which is contained in pixel F' of the image 101', in order not to dazzle the pedestrian or the oncoming driver located at the corresponding region or pixel of the target field, the controller 50 dims or extinguishes the light output from the corresponding light emitting elements E (which is shown in the drawings) and F (not shown).

As an alternative response, the controller might be configured to change the emitted frequency of the light from those elements (or in other applications, for example, to initiate light emission from those elements or to increase the intensity of light emission from those elements.)

As shown, the light detector may comprise an array 30 of light detecting elements, the lens body 1 being arranged to project an image 100' from the subject plane F3 onto the array.

Alternativeliy, the light detector may be a scanning light detector for detecting light from a target point T1 on the subject plane. In such embodiments the apparatus further includes a beam director 70. The beam director 70 is arranged to scan a region of the subject plane F3 by moving the target point across the region of the subject plane F3 while directing the respective, first or second portion L1, L2 of the light received from the target point to enter the lens body 1 to travel to the scanning light detector. The controller 50 is arranged to control the beam director 70 and to process the signal from the scanning light detector to generate the image of the target field. In such embodiments, the light detector may be arranged in the second light handling unit 20 while the light emitter is arranged in the first light handling unit 10.

Aithough only a few light emitting or detecting elements are shown in the example of Figs. 18 and 19, in any embodiment the array 30 of light emitting elements may include at least 25 light emitting elements, with the controller 50 being operable to identify and selectively adjust a subset comprising any combination of the 25 light emitting elements.

The controller 50 may be configured to selectively extinguish or reduce a radiant intensity of the light emitted by the identified subset of light emitting elements. Optionally, each of the light emitting elements 31 may comprise a plurality of sub-elements 31', for example as shown in Fig. 11, which are configured to emit light at different wavelengths and individually controllable by the controller 50, which is configured to selectively alter a wavelength of the light emitted by the identified subset of light emitting elements.

For example, if a head-up display or other display is provided, such as in a motor vehicle or other application, then the controller 50 might be configured to show theimage 101' on the display wherein the subset of pixels corresponding to the subset of light emitting elements 31' are shown in the modified wavelength (e g. infra-red) so that the driver or other user can maintain awareness of the elements of the image contained in those pixels but no longer illuminated by the primary wavelength, e.g. v isible light.

The apparatus may be mounted on a vehicle to provide forward illumination, for example, as one headlight of the vehicle, in which case the apparatus may be arranged in a fixed position on the vehicle or may be adjustably mounted in accordance with any of the above described mounting configurations. Where a beam director 70 is provided, the beam director 70 or actuator 71 may be arranged to provide load compensation or other adjustment of the direction of the beam from the lens body as known in the art.

The array 30 may be arranged to detect iight in a first frequency range, while another scanning light detector 12 or 22 is arranged to detect Iight in a second, different frequency range.

In each embodiment, a separate Iight source, for example, a millimetre wave source, may be arranged to illuminate the subject with the light (whether visible or Invisible) that is detected by the or each Iight detector.

Optionally, a display such as a screen may be arranged to receive and display a first image generated from a signal from the array 30 and a second image generated from the signal from the scanning light detector, the first and second images being superimposed.

Where a user interface 60 is provided, the controller may be arranged to receive via the user interface 60 a user input defining a region of a first image 101' generated by the array 30, and to operate the beam director 70 (e.g, actuator 71) to scan the region of the subject plane corresponding to the region of the first image defined by the user input.

The light emitter or emitters may be arranged to project separate illumination and detection light beams, wihch may be emitted by different light emitting elements (e.g. laser and LED) and may be chosen as required from different bands of the electromagnetic spectrum, for example, ultraviolet, visible, and/or infrared. For example, a detection beam may be emitted in one part of the spectrum (e.g. infra red) and superimposed onto an image emitted in another part of the spectrum, e.g. the visible part of the spectrum. The detection beammight be detected by the detector and used for example by projecting a pattern onto the target surface to build a 3D Image of the surface or as a graticule to identify the spatial coordinates of each pixel of the image.

A light detector may comprise a simple light detector for discriminating between the presence and absence of light, and/or any other suitable means for detecting light in the visible or non- visible parts of the spectrum, which may be emitted from the subject plane and/or reflected from ambient light or from the illumination or detection light beams projected onto the subject piane.

The or each light detector may detect radiant intensity, wavelength, and/or other measurable parameters. The detector may be arranged to provide a response to the detected light, for example, to indicate the intensity of light detected in a particular wavelength. The detector might provide an indication that the detected light falling on a target surface, e.g. a human body surface or a group of growing plants, is deficient in a particu!ar wavelength.

A light detector confgured as an array 30 may comprise a charge coupled device or digital camera system for resolving images. The detector may be configured to produce an output signal representing an image of the target surface, wherein the signal can be processed by the controller 50 to indicate individual pixels of the image 101' representing the light received from individual portions or pixels of the target surface. Thus, the processor may determine from the signal the distribution of light over the target surface. The digitised image from the detecto may comprise a matrix of pixels, each pixei corresponding to a spatial coordinate in the observed target field, which may be mapped (e.g by means of a data record held in the memory of the controller) to individual pixels or light emitting elements of the light emitter or emitters.

The controller 50 may form part of a computer system including a processor, a memory, a physical user interface 60 with a screen and keyboard, suitable software for procesing signals from the or each detector and controlling the or each light emitter, and/or actuators71 for focussing and rotating the lens body 1 or other adjustable optica! element of the system. The processor may control the projected light responsive to signals from the detector which receives the light emitted or reflected from the target surface. For example, the processor may analyse the signal from the detector and invoke an adjustment of the direction of the beam or the wavelength or intensity of the illumination from the light emitter. For example, if the signal indicates a deficiency in a particular wavelength of light falling on the target surface, the processor might be arranged to energise the light source to emit light in the deficient portion of the spectrum, for example, to enhance the therapeutic application of natural daylight to the human body, or to promote healthy plant growth in a greenhouse.

Each light emitting element may be a single source such as an LED or may be a compound element comprising an array of primary light emitting elements, e.g. LEDs, each emitting light at a different wavelength. An example is the LZ7 7 wavelength emitter supplied by Led Engin of California, USA. The primary light emitting elements, e.g. LEDs may be individually addressable. The controller may be configured to select a desired wavelength of the emitted light by adjusting together all the primary light emitting elements of the same wavelength, e.g. to increase the output at the red end of the spectrum relative to the blue end of the spectrum. The spatial distribution of light across the target surface will be determined by the optical system and by the spatial distribution of light across the 2D array of light emitters and so can be adjusted by individually adjusting the radiant intensity (power input) of each group of primary light emitting elements forming a compound light emitting element - i.e. the power to the compound element can be adjusted to tweak up or down the output of all its primary elements. Thus, overall wavelength can be adjusted across the whole light source, and radiant intensity can be adjusted pixel by pixel. Of course, other adjustment regimes may be implemented by suitably configuring the electrical control lines (not shown) to address the LEDs individually or group by group, as required. A waveguide or a bundle ofwaveguides (one for each light emitting element) may be arranged to conduct light from the light emitting array to the lens body. The waveguide or waveguide bundle may further be arranged for safety to scramble the light rays from each point light source to provide a family of non-parallel rays within a small cone angle, the rays being randomised within the beam so that the light source cannot be imaged onto the user's retina.

Due to the potential for complex mode paths in the waveguide there may not be a simplistic relationship between the nature of the light field at the emitting end of the waveguide relative to the illumination at the launch end. However, a complex spatial relationship may exist, so that the light emitting elements can still be correlated with individual, perhaps overlapping target points or pixels on the illuminated subject plane.

In summary, embodiments provide a light emitting and detecting apparatus comprising a catadiptric lens body containing an integral reflector within a spherical lens and defining first and second conjugate focal planes at which a light emitting array and a light detector are arranged to emit and detect light incident on a target field along a common axis. A controller processes an image received from the detector to determine whether a predefined element is contained in the target field and selectively adapts the output of a subset of the light emitting elements of the array to modify the illumination of the corresponding region of the target field.

The features of the various aspects and embodiments of the invention may be combined together in any desired combination. Further possible adaptations within the scope of the claims will be apparent to those skilled in the art.

In the claims, reference numerals and characters in parentheses are provided for ease of reference and should not be construed as limiting features.

Claims

1. An apparatus for emitting and detecting light travelling along a first axis, including: a controller,

a lens body, and

first and second light handling units;

the lens body including a bail and a reflector contained within the ball,

the bail being transparent and having a surface, the surface defining a total surface area of the ball and having substantially spherical curvature over substantially all of the total surface area;

wherein, when the reflector is considered as projected along the first axis onto a reflector plane, the reflector plane being a nominal plane passing centrally through the bail and normal to the first axis, the reflector occupies less than all of an area of the reflector plane bounded by the surface;

the apparatus being arranged to define first and second conjugate focal planes relative to a subject plane,

and to transmit light entering or leaving the lens body along the first axis and travelling between the lens body and the subject plane, such that:

a first portion of the light travels through the ball and past the reflector between the subject plane and the first light handling unit located at the first conjugate focal plane, and a second portion of the Sight travels through the ball and is reflected from the reflector between the subject plane and the second light handling unit located at the second conjugate focal plane;

wherein a respective one of the first and second Sight handling units includes a light emitter, and the respective other one of the first and second light handling units includes a light detector;

and the light emitter comprises an array of light emitting elements,

each of the light emitting elements being individually controllable by the controller, and the apparatus is arranged to project light emitted from the array along the first axis to illuminate a target field of the subject plane, such that the light emitted from each of the light emitting elements illuminates less than all of the target field;

and the detector is arranged to generate a signal representing an image of the target field; and the controller is arranged:

to receive the signal from the detector;

to process the signal to identify whether a predefined element is present in the image;

and then, responsive to identifying the predefined element,

to identify a subset of the light emitting elements from which light is emitted and projected onto a region of the target field containing said predefined element, and

to selectively adjust the light emitting elements to obtain a different light output condition of the light emitting elements contained in the subset relative to the light emitting elements not contained in the subset.

2. An apparatus accordiing to claim 1, wherein the light detector comprises an array of light detecting elements.

3. An apparatus accordiing to claim 1, wherein the light detector is a scanning light detector for detecting light from a target point on the subject plane;

and further including a beam director;

the beam director being arranged to scan a region of the subject plane by moving the target point across the region of the subject plane while directing the respective, first or second portion of the light received from the target point to enter the lens body to travel to the scanning light detector;

the controller being arranged to control the beam director and to process the signal from the scanning light detector to generate the image of the target field.

4. An apparatus according to any of claims 1 - 3, wherein the first light handling unit includes the light detector, and the second light handling unit includes the light emitter.

5. An apparatus according to any of claims 1 - 3, wherein the second light handling unit includes the light detector, and the first light handling unit includes the light emitter.

6. An apparatus according to any preceding claim, wherein the array includes at least 25 light emitting elements, and the controller is operable to identify and selectively adjust a subset comprising any combination of the 25 light emitting elements.

7. An apparatus according to any preceding claim, wherein the controller is configured to selectively extinguish or reduce a radiant intensity of the light emitted by the identified subset of light emitting elements.

8. An apparatus according to any preceding claim, wherein each of the light emitting elements comprises a plurality of sub-elements configured to emit light at different wavelengths and individually controllable by the controller, and the controller is configured to selectively alter a wavelength of the light emitted by the identified subset of light emitting elements.

9. An apparatus according to any preceding claim, wherein each of the light emitting elements is provided with a respective waveguide, the waveguide being arranged to transmit light from the respective light emitting element to the respective conjugate focal plane.

10. An apparatus according to any preceding claim, wherein the apparatus is mounted on a vehicle to provide forward illumination.