GB2500366A

GB2500366A - Media exposure device system and method

Info

Publication number: GB2500366A
Application number: GB201201765A
Authority: GB
Inventors: Trevor Elworthy
Original assignee: Lumejet Holdings Ltd
Current assignee: Lumejet Holdings Ltd
Priority date: 2012-02-01
Filing date: 2012-02-01
Publication date: 2013-09-25
Also published as: GB201201765D0; WO2013114130A2; WO2013114130A3

Abstract

A media exposure device 10 includes a plurality of radiating elements 22; radiation emitted by one or more of the radiating elements 22 corresponds to one of a set of aligned points located on an outwardly facing surface of the device; the radiating elements 22 being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time. The points preferably form a two dimensional array; the radiating elements are preferably infrared micro light emitting diodes and the device forms part of a printhead.

Description

MEDIA EXPOSURE DEVICE, SYSTEM AND METHOD The present invention relates to a media exposure device, system and method.

STATEMENTS OF INVENTION

According to a first aspect of the invention there is provided a media exposure device, the media exposure device including a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time.

According to a second aspect of the invention, there is provided a media exposure device, the media exposure device including a plurality of radiating elements; and radiation modification means for modifying radiation originally emitted by the radiating elements to a uniform field of radiation and for emitting from the device the uniform

field of radiation.

According to a third aspect of the invention there is provided a system for exposing a media of which a surface area contains a photopolymer substance, the system including a first infrared media exposure device, the first infrared media exposure device including a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time; the first infrared media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the radiation emitted from the points located along the outwardly facing surface of the device, such that each surface area of the media which is to be exposed can be exposed to radiation emitted from one or more of the points of a particular one of the sets of points.

The system may include an ultraviolet media exposure device, the ultraviolet media exposure device including a plurality of ultraviolet radiating elements; and ultraviolet radiation modification means for modifying radiation originally emitted by the ultraviolet radiating elements to a uniform field of ultraviolet radiation and for emitting from the device the uniform field of ultraviolet radiation; the first infrared media exposure device and the ultraviolet media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the uniform field of ultraviolet radiation from the ultraviolet media exposure device in rapid succession to the exposure by the first media exposure device.

The system may include a second infrared media exposure device including a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time; the first infrared media exposure device, the ultraviolet media exposure device and the second infrared media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the radiation emitted from the points located along the outwardly facing surface of the second infrared media exposure device in rapid succession to the exposure by the ultraviolet media exposure device and wherein each surface area of the media which is to be exposed can be exposed to radiation emitted from one or more of the points of a particular one of the sets of points of the second infrared media exposure device, the set of points of the second infrared media exposure device corresponding to a set of points of the first infrared media exposure device.

According to a fourth aspect of the invention there is provided a method of exposing a media of which a surface area contains a photopolymer substance, the colour of the photopolymer substance being determined by the degree of polymerisation thereof, the method including the following steps in sequence for each surface area spot which is to be exposed: exposing the surface area spot to a first series of exposures of infrared radiation within a predetermined time, thereby cumulatively increasing the temperature of the photopolymer substance of the surface area spot to at least a predetermined activation temperature to allow for the polymerisation of the photopolymer substance of the surface area spot on the subsequent application of ultraviolet radiation of a predetermined amplitude and a predetermined duration to the surface area spot; exposing the surface area spot to the ultraviolet radiation of the predetermined amplitude and the predetermined duration; and exposing the surface area spot to a second series of exposures of infrared radiation within a predetermined period of time, thereby cumulatively further polymerising the photopolymer substance of the surface area spot to a degree determined by the required colour of the surface area spot.

According to a further broad aspect of the invention, there is provided a media exposure device for exposing a media, the media exposure device including a plurality of radiating elements, the radiating elements being aligned with one another in sets; and means for controlling the radiating elements so that radiation is emitted from one or more radiating elements in a particular set one after the other in the order in which the radiating elements are aligned such that the cumulative power of the radiation emitted from a particular set within a predetermined time is sufficient to at least partially activate a particular area of the media as the media moves relative to the device.

The terms medium I media, as used herein, refer to any media that may be exposed so that an image, pattern or mark can then be generated on the media. An illustrative example of such media is photographic paper. It should also be remembered that where the term printing' or other related terms are used, we do not intend to refer to the deposition of inks and such like onto media. In general terms, printing' in the context of the present application is the exposure of print media with light and/or radiation, and the treatment of that media to yield an image, pattern or mark.

The invention extends to any novel aspects or features described and/or illustrated herein.

Further features of the invention are characterised by the other independent and dependent claims.

The invention extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features disclosed in the description, and (where appropriate) the claims and drawings in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.

Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

BRIEF DESCRIPTION OF DRAWINGS

Further features of the invention are described hereinafter by way of a non-limiting example of the invention with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings: Figure 1 shows a schematic view of a media exposure device in accordance with the invention; Figure 2 shows a schematic view of the emission of radiation from points corresponding to multiple radiation elements by a media exposure device in accordance with the invention; Figure 3 shows a schematic view of a microlens array of the media exposure device of Figure 1; Figure 4 shows a schematic view of micro LEDs, a plurality of telecentric lenses and an optic fibre bundle corresponding to each telecentric lens of a media exposure device in accordance with the invention; Figure 5a shows a front view of an ultraviolet media exposure device in accordance with the invention, together with a side view of the ultraviolet media exposure device; Figure Sb shows a top view of the ultraviolet media exposure device of Figure 5a together with a side view of the ultraviolet media exposure device sectioned along section lines B-B; Figure Sc shows a top view of the ultraviolet media exposure device of Figure 5a with the cylindrical lens removed; Figure 6 shows a schematic view of a system for exposing a media of which a surface area contains a photopolymer substance in accordance with the invention; Figure 7 shows a flowchart describing a method for exposing a media of which a surface area contains a photopolymer substance in accordance with the invention; Figure 8 shows a schematic view of another example of a system for exposing a media in accordance with the invention; Figure 9 shows a media preheating device and a first infrared media exposure device of the system of Figure 8 together with the first infrared media exposure device of the system of Figure 6; and Figure 10 shows a flowchart describing another example of a method for exposing a media of which a surface area contains a photopolymer substance in accordance with the invention.

DETAILED DESCRIPTION

With reference to Figure 1 and Figure 3 of the drawings, a media exposure device for exposing a media, in accordance with a first aspect of the invention, is designated, generally, by the reference numeral 10.

The media exposure device 10 includes, broadly, a plurality of radiating elements 12 mounted on a mounting structure 14 and radiation modification means 16.

The mounting structure is in the form of an elongated bar 18. The elongated bar includes a plurality of elongated chips 20 which are aligned end-to-end and in abutment with one another. The plurality of radiating elements is in the form of micro Light Emitting Diodes (LED5) 22. The radiation modification means is in the form of a microlens array 24.

A different subset of the micro LEDs 22 are mounted on each of the chips 20 in an arrangement wherein they are substantially equidistantly spaced in columns and rows of a substantially two dimensional array along a surface area of the chip. Each of the micro LEDs are mounted on the chip in the same orientation. The chips are accurately aligned with one another in an arrangement wherein the micro LED arrays of the individual chips together constitute a substantially equidistantly spaced two-dimensional array of micro LEDs with the same orientation along the length of the bar 18. Adjacent columns and rows of the two-dimensional array of the bar are offset relative to one another.

More specifically, each of the chips 20 is fabricated on a single substrate by monolithic (solid-state) techniques, each chip including the micro LEDs 22, interconnections and drive circuitry. The construction of the chips will allow for them to be accurately aligned with one another either by mechanical means (e.g. plugged into a base board) or physical means (e.g. solder bumps in combination with a micro bench), such that the micro LED spacing is preserved from one chip to the next, to create a finished bar 18 of chips of the required length. The length of the bar may, for example, be dictated by the width of the media which is to be exposed by the media exposure device.

Each micro LED 22 is individually controllable by high speed digital logic (FPGAs or ASICs) to set its current, voltage and exposure time. Each of the micro LEDs is powered to the same extent when switched on. Each of the micro LEDs consequently emits radiation with substantially the same radiation pattern and substantially the same amplitude when switched on. Alternatively, each of the individual LEDs is variably powered, the micro LEDs consequently emitting radiation of the same radiation pattern but with variable amplitudes.

In use, each micro LED 22 exposes one surface area spot at a time on the surface of the media. The offset of the columns and rows of micro LEDs in successive rows provide some Gaussian overlap of adjacent exposed surface area spots to avoid micro-banding effects on the exposed media.

In use, the micro LEDs 22 in each row are capable of rapid ripple firing, thereby to allow for the same surface area spot of the media to be exposed multiple times as the media passes under the LEDs. The exposures by the individual LEDs are thus added together to create an overall level of power of exposure determined by the size of each micro LED, the number of micro LEDs in each row, the output power of each micra LED, the length of time each micra LED is on and the speed of the media passing under the micro LEDs.

The microlens array 24 is mounted adjacent to the two-dimensional array of micro LEDs 22 in an arrangement wherein each lens of the microlens array is aligned with a particular micro LED.

In use, radiation emitted by each micro LED 22 is emitted from the media exposure device from a point located along an outwardly facing surface of the lens of the microlens array 24 which is aligned with the micro LED. Each lens focuses the radiation of its corresponding LED at a distance which is within a particular range of distances from the device.

The micro LEDs 22 have a predetermined size ranging in the micro range, typically from 2Opm to 150pm and a predetermined wavelength ranging from 1000-l500nm (infrared) for printing and patterning of photo-activated polymers.

With reference to Figure 2 of the drawings, another example of the media exposure device in accordance with the first aspect of the invention is designated, generally, by the reference numeral 50.

This example of the media exposure device 50 differs from the media exposure device 10 described hereinabove in the respect that it includes radiation combination means in the form of a polarising beam splitter 52. The polarising beam splitter combines the radiation 54 emitted by pairs of corresponding micro LEDs. The combined radiation 56 of each pair of corresponding micro LEDs is then focused by a corresponding lens of the microlens array at a distance which is within a particular range of distances from the device.

In yet another example (not shown) of a media exposure device in accordance with the first aspect of the invention, the media exposure device differs from the media exposure device described hereinabove in that the radiation modification means comprises one telecentric lens.

In use, radiation emitted by each micro LED is emitted from this example of the media exposure device from a point located along an outwardly facing surface of the telecentric lens. The telecentric lens focuses radiation emitted by the micro LEDs at a distance which is within a particular range of distances from the device.

With reference to Figure 4 of the drawings, a further example of a media exposure device in accordance with the first aspect of the invention is designated, generally, by the reference numeral 100. The media exposure device 100 differs from the media exposure device described hereinabove in that the radiation modification means comprises of a plurality of telecentric lenses 102, each telecentric lens corresponding to a different subset of the micro LEDs 104; and a bundle of optic fibres 106 corresponding to each telecentric lens.

In use, radiation emitted by each micro LED 104 is emitted from the media exposure device from a point located at the end of an optic fibre bundle 106 corresponding to the telecentric lens 102 which corresponds to the micro LED. The radiation of the micro LED is emitted by the telecentric lens and then conducted by the bundle of optic fibres corresponding to the telecentric lens. The bundle of optic fibres then focuses the radiation emitted by the micro LED at a distance which is within a particular range of distances from the device. The ends of the bundles of optic fibres from where the radiation is emitted are arranged adjacent and in line with one another, thereby focusing the radiation emitted by the micro LEDs as equidistantly spaced beams of radiation which are in alignment at a distance from the device which is within a particular range of distances from the device.

In a further example (not shown) of a media exposure device in accordance with the first aspect of the invention, the media exposure device differs from the media -10-exposure device described hereinabove in that the radiation modification means comprises of a tapered bundle of optic fibres. The fibres are of a predetermined length. The tapered bundle defines a wide end and a narrow end and is disposed in an arrangement wherein the points are defined along the narrow end of the tapered bundle.

In use, radiation emitted by each micro LED propagates from the wide end to the narrow end of the tapered bundle. Radiation emitting from the narrow end of the tapered bundle is focused at a distance from the media exposure device.

In yet a further example (not shown) of a media exposure device in accordance with the first aspect of the invention, the media exposure device differs from the media exposure device described hereinabove in that the radiation modification means comprises a macrolens array (e.g. a FOCAL lens as provided by Nippon Glass).

Each lens of the macrolens array is disposed in an arrangement wherein the radiation emitted by a group of micro LEDs is focused by it at a distance which is within a particular range of distances from the device.

The applicant envisages that the use of micro LEDs together with one of a telecentric lens, a plurality of telecentric lenses and corresponding optic fibre bundles, a tapered bundle of optic fibres or a macrolens array will allow for the printing or patterning of smaller (sub-bum) surface area spot sizes as are required for patterning of Thin-film Transistors and other electronic components, conductor tracks etc. in flexible substrates.

It will be appreciated that should a high resolution of radiation points not be a requirement, macro LEDs can be substituted for micro LEDs in the above examples wherein the radiation modification means include one of a telecentric lens, a plurality of telecentric lenses and corresponding optic fibre bundles, a tapered bundle of optic fibres or a macrolens array. More particularly, wafer scale macro LEDs with a diameter in the range of 0.25 mm to 1 mm can be substituted for the micro LEDs. For detail on the use of macro LEDs together with a telecentric lens in a media exposure device, please refer to the United Kingdom patent application filed by the present applicant on the same day as this application, entitled "RADIATING DEVICE AND MEDIA EXPOSURE DEVICE" (Agent Reference: P38047GB), the entire contents of which is hereby incorporated by reference herein.

It will be further appreciated that the radiation elements may be constituted by a plurality of any one of fibre coupled laser diodes, edge emitting lasers or other radiation elements, provided that the required resolution of surface area spots can be achieved.

With reference to Figures 5a to Sc of the drawings, a media exposure device, in accordance with a second aspect of the invention, is designated, generally, by the reference numeral 150.

The media exposure device includes, broadly, a plurality of ultraviolet radiating elements 152 mounted on a mounting structure 154 and radiation modification means 156.

The radiating elements are in the form of macro ultraviolet Light Emitting Diodes 158.

The mounting structure is in the form of an elongated bar 160. The radiation modification means is in the form of an elongated cylindrical lens 162.

The macro ultraviolet Light Emitting Diodes 158 are substantially equidistantly spaced with the same orientation in a two-dimensional array and substantially co-planar. The cylindrical lens 162 is disposed transverse to the direction of the radiation emitted by the radiating elements.

In use, the cylindrical lens 162 modifies radiation originally emitted by the macro ultraviolet Light Emitting Diodes 158 to a uniform field of radiation and emits from the

device the uniform field of radiation. -12-

It will be appreciated that the ultraviolet radiating elements may be radiating elements other than ultraviolet macro LEDs.

The applicant envisages that the media exposure device will be utilised for overall illumination of media containing photo-activated polymers as well as in ultraviolet curing applications.

With reference to Figure 6 of the drawings, a system for exposing a media of which a surface area contains a photopolymer substance, in accordance with a third aspect of the invention is designated, generally, by the reference numeral 250. The system includes, broadly, a first infrared media exposure device 252, an ultraviolet media exposure device 254 and a second infrared media exposure device 256.

The first infrared media exposure device 252 is the example 10 of the media exposure device of the first aspect of the invention described hereinabove.

The ultraviolet media exposure device 254 is the example 150 of the media exposure device of the second aspect of the invention described hereinabove.

The second infrared media exposure device 256 is the example 10 of the media exposure device of the first aspect of the invention described hereinabove.

The ultraviolet media exposure device 254 is disposed between and adjacent to the first infrared exposure device 252 and the second infrared media exposure device 256. The first and second infrared media exposure devices are arranged such that the radiation emitted from the lenses of the microlens arrays of the first and the second infrared media exposure devices have spatial radiation patterns with substantially the same orientation. The uniform field of ultraviolet radiation emitted from the ultraviolet radiation device has substantially the same direction as the radiation emitted from the microlens arrays. The media exposure devices define radiation faces from which the media can be exposed. -13-

In use, the media disposed in parallel and in motion relative to the radiation faces of the devices can be exposed in rapid succession to infrared radiation from a plurality of points of the first infrared media exposure device 252, followed by ultraviolet radiation from the ultraviolet media exposure device 254, followed by infrared radiation from a plurality of points of the second infrared media exposure device 256.

Radiation from each point of the second infrared media exposure device excites substantially the same surface area of the media as radiation from a corresponding point of the first infrared media exposure device, thereby to print onto the media.

With reference to Figure 7 of the drawings, a method for exposing a media of which a surface area contains a photopolymer substance is designated, generally, by the reference numeral 300.

The colour of each surface area spot of the media is determined by the degree of polymerisation of the photopolymer substance thereof. The method comprises a number of steps in sequence for each surface area spot which is to be polyrnerised.

The surface area spot is first exposed (Block 302) to exposures of infrared radiation of a common predetermined amplitude and a common predetermined duration a predetermined number of times in rapid succession. The temperature of the surface area spot is increased to a predetermined activation temperature to allow for the polymerisation of the photopolymer substance thereof on the application, immediately after the application of the infrared radiation, of ultraviolet radiation of a predetermined amplitude and duration. Alternatively, the predetermined number of exposures can each have a predetermined particular amplitude and a predetermined particular duration particular to the exposure.

The surface area spot is then exposed (Block 304) to the ultraviolet radiation of the predetermined amplitude and duration.

Immediately after the exposure of the surface area spot with ultraviolet radiation, the surface area spot is exposed (Block 306) with further exposures of infrared radiation, -14-thereby further polymerising the photopolymer substance of the surface area spot.

The amplitude and duration of each exposure of the further infrared radiation is determined by the required degree of polymerisation of the surface area spot as determined by the required colour of the surface area spot.

The method 300 can be implemented utilising the system 250 for exposing a media of which a surface area contains a photopolymer substance described hereinabove.

More specifically, in the implementation of the method 300 using the system 250, surface area spots falling along lines transverse to the movement of the media through the system are exposed simultaneously by columns of the infrared micro LEDs of the first infrared media exposure device as the media moves relative to the device. Each surface area spot which is to be printed is exposed a number of times equal to the number of micro LEDs in each row of the first infrared media exposure device 252. Since the first infrared media exposure device exposes surface area spots for purposes of increasing the temperature of the surface area spot to the predetermined activation temperature, exposed spots are all exposed to the same degree. Each micro LED in the row of the first infrared media exposure device corresponding to the spot is switched on and radiating at the common amplitude for the common duration as the spot passes its radiation path. Alternatively, each micro LED is switched on and radiating at the particular amplitude and the particular duration for the micro LED and the spot as the spot passes the micro LED's radiation path. The exposures of infrared radiation cumulatively increase the temperature of the surface area spot to the predetermined activation temperature. The micro LEDs are switched off for spots which are not exposed as the spots passes their respective radiation paths Further, the ultraviolet macro LEDs of the ultraviolet media exposure device 254 are always on as the media passes through the system. Consequently, all the surface area spots of the media are exposed by the ultraviolet media exposure device to the same extent as the media passes through the radiation path of the ultraviolet media exposure device. The ultraviolet exposure of surface area spots which were exposed -15-by the first media exposure device results in the polymerisation of the photopolymer substance of the spots, thereby resulting in the surface area spots obtaining a blue colour.

Still further, surface area spots falling along lines transverse to the movement of the media are exposed simultaneously by columns of the infrared micro LEDs of the second infrared media exposure device 256 as the media moves relative to the device. Each printed surface area spot which is to undergo a colour change is exposed a number of times equal to the number ot micro LEDs in each row of the second infrared media exposure device. Since the second infrared media exposure device exposes surface area spots for purposes of polymerising the spot to the extent required for the spot to obtain its required colour, each micro LED in the row of the second infrared media exposure device corresponding to the spot is switched on and radiating at a predetermined amplitude and for a predetermined duration as the spot passes its radiation path. The amplitude and duration is common to all the exposures of the spot by the micro LEDs of the row. The amplitude and duration is determined by the cumulative radiation of the micro LEDs of the row required to achieve the required colour of the spot.

Alternatively, each micro LED in the row of the second infrared media exposure device corresponding to the spot is switched on and radiating at a predetermined amplitude and a predetermined duration as the spot passes the micro LED's radiation path. The amplitude and duration is particular to each micro LED. The cumulative radiation of the micro LEDs of the row achieves the required colour ot the spot.

With reference to Figure 8 of the drawings, another example of a system for exposing a media of which a surface area contains a photopolymer substance in accordance with a third aspect of the invention is designated, generally, by the reference numeral 350. The system 350 differs from the system 250 in that it includes a media preheating device 358. The devices of the system 350 which corresponds with those of the system 250 are designated by corresponding reference numerals. -16-

The media preheating device 358 is disposed adjacent the first infrared exposure device. The media preheating device 358 includes a plurality of radiating elements in the form of macro infrared LEDs 360 which are in an arrangement wherein the radiation is emitted from an outwardly facing surface of the media preheating device.

Alternatively, the media preheating device is in the form of a heated roller (not shown) over which the media can be passed.

With reference to Figure 10 of the drawings, another example of a method for exposing a media of which a surface area contains a photopolymer substance in accordance with the invention using the system 350 is designated, generally, by the reference numeral 400. The method 400 differs from the method 300 in that it includes preheating (Block 408) of the media. The method steps of the method 400 which corresponds with those of the method 300 are designated by corresponding reference numerals.

The media is pre-heated by the media preheating device 358 to a predetermined first temperature which is lower than the predetermined activation temperature before it is exposed to the infrared radiation of the first infrared media exposure device 352. The degree of thermal excitation by the first infrared media exposure device 352 required per surface area spot which is being exposed by the first infrared media exposure device is that required to increase the temperature from the predetermined first temperature to the predetermined activation temperature. Consequently, with reference to Figure 9, the number of required micro LEDs per row of the first infrared media exposure device 352 of the system 350 is less than the number of required LEDs of the first infrared media exposure device 252 of the system 250. For example, where a first media exposure device with 20 micro LEDs per row was required to excite a spot on the media to the predetermined activation temperature without a media preheating device, the system for exposing a media 350 may require a first media exposure device having only 2 micro LEDs per row.

A further example (not shown) of a method for exposing a media of which a surface area contains a photopolymer substance in accordance with the invention and using -17-the system 250 differs from the method 300 in that the shade of the colour of each exposed surface area spot is determined by the extent to which the temperature of the photopolymer substance of the spot is increased above the activation temperature before the photopolymer substance of the spot is polymerised.

The cumulative exposures by the first infrared media exposure device of each surface area spot which is being exposed thus increases the temperature of the surface area spot to a temperature which exceeds the activation temperature to an extent determined by the required shade of the colour ot the surface area spot.

The applicant envisages that the media exposure device, system and method will be utilised for printing and patterning photo-activated media, such as black-and-white and colour-change polymers in inkless printing applications such as labelling and packaging.

The applicant also envisages that variations on the preferred example of the media exposure device, system and method will provide for exposure of a media at visual, ultraviolet and other wavelengths. Chips and bars of different radiating element sizes, wavelengths and power can be assembled for other applications e.g. photo printing on silver halide based coatings, printed circuit boards and printed electronics patterning using photo-resists.

It will be understood that the present invention has been described above purely by way ot example, and modifications of detail can be made within the scope of the invention.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims. -18-

Claims

Claims: 1. A media exposure device, the media exposure device including: a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time.
2. A media exposure device according to claim 1, wherein the timing and amplitude of the radiation emitted by each radiating element is individually controllable.
3. A media exposure device according to claim 1 or claim 2, wherein the points are substantially equidistantly spaced and substantially co-planar.
4. A media exposure device according to any one of claims 1 to 3, wherein the points are arranged in a two-dimensional array of which adjacent columns and rows are offset relative to one another.
5. A media exposure device according to any one of claims 1 to 4, wherein the radiation emitted from each point has substantially the same radiation pattern. -19-
6. A media exposure device according to any one of claims 1 to 5, wherein the radiation emitted from each point has substantially the same amplitude.
7. A media exposure device according to any one of claims 1 to 6, wherein the radiating elements are substantially equidistantly spaced and substantially co-planar.
8. A media exposure device according to any one of claims 1 to 7, wherein the radiating elements are arranged in a two-dimensional array of which adjacent columns and rows are offset relative to one another.
9. A media exposure device according to any one of claims 1 to 8, wherein the radiation emitted by each radiating element has substantially the same radiation pattern.
10. A media exposure device according to any one of claims 1 to 9, wherein the radiation emitted by each radiating element has substantially the same amplitude.
11. A media exposure device according to any one of claims 1 to 10, including radiation combination means for combining radiation emitted by more than one radiating elements corresponding to a point, the combined radiation being emitted from the point.
12. A media exposure device according to claim 11, wherein the radiation combination means is in the form of an polarising beam splitter.
13. A media exposure device according to any one of claims 1 to 12, including radiation modification means for modifying and emitting from the device radiation originally emitted by the radiating elements, each point being defined by a surface area of the radiation modification means from which the radiation -20 -originating from the corresponding particular one or more radiating elements emits from the device.
14. A media exposure device according to claim 13, wherein the radiation modification means includes a tapered bundle of optic fibres of a predetermined length, each fibre having substantially the same orientation and substantially the same tapered profile, the tapered bundle thereby defining a planar wide end and a planar narrow end and being disposed in an arrangement wherein the points are defined along the narrow end of the tapered bundle.
15. A media exposure device according to claim 13, wherein the radiation modification means includes at least one lens, each lens being disposed in an arrangement wherein one or more of the points are defined by a surface area of the lens, the radiation emitted by the device from each of the points being focused by the lens at a distance which is within a particular range of distances from the device.
16. A media exposure device according to claim 15, wherein the radiation modification means comprises a macrolens array.
17. A media exposure device according to claim 15, wherein the radiation modification means comprises at least one telecentric lens.
18. A media exposure device according to claim 15, wherein the radiation modification means comprises a plurality of telecentric lenses and a bundle of optic fibres corresponding to each telecentric lens.
19. A media exposure device according to claim 15, wherein the radiation modification means comprises a microlens array.

-21 -
20. A media exposure device according to any one of claims 1 to 18, wherein the radiating elements comprise macro Light Emitting Diodes.
21. A media exposure device according to any one of claims 1 to 19, wherein the radiating elements comprise micro Light Emitting Diodes.
22. A media exposure device, the media exposure device including: a plurality of radiating elements; and radiation modification means for modifying radiation originally emitted by the radiating elements to a uniform field of radiation and for emitting from thedevice the uniform field of radiation.
23. A media exposure device according to claim 22, wherein the plurality of radiating elements are substantially equidistantly spaced in a two-dimensional array and substantially co-planar.
24. A media exposure device according to claim 22 or claim 23, wherein the plurality of radiating elements comprises a plurality of macro Light Emitting Diodes.
25. A media exposure device according to any one of claims 22 to 24, wherein the radiation modification means is in the form of elongated cylindrical lens, the lens being disposed transverse to the direction of the radiation emitted by the radiating elements.
26. A system for exposing a media of which a surface area contains a photopolymer substance, the system including: a first infrared media exposure device, the first infrared media exposure device including: -22 -a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time; the first infrared media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the radiation emitted from the points located along the outwardly facing surface of the device, such that each surface area of the media which is to be exposed can be exposed to radiation emitted from one or more of the points of a particular one of the sets of points.
27. A system according to claim 26, the system including: an ultraviolet media exposure device, the ultraviolet media exposure device including: a plurality of ultraviolet radiating elements; and ultraviolet radiation modification means for modifying radiation originally emitted by the ultraviolet radiating elements to a uniform field of -23 -ultraviolet radiation and for emitting from the device the uniform field of ultraviolet radiation; the first infrared media exposure device and the ultraviolet media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the uniform field of ultraviolet radiation from the ultraviolet media exposure device in rapid succession to the exposure by the first media exposure device.
28. A system according to claim 27, the system including: a second infrared media exposure device including: a plurality of radiating elements; radiation emitted by the radiating elements being emitted from the device from one or more sets of points located along an outwardly facing surface of the device, the points of each set being aligned with one another, each point corresponding with a different one or more of the radiating elements; the radiating elements corresponding to each set of points being operable to cause radiation to be emitted from one or more points of the set one after the other in the order in which the points of the set are aligned such that, cumulatively, radiation of a predetermined power is emitted from the points of the set within a predetermined time; the first infrared media exposure device, the ultraviolet media exposure device and the second infrared media exposure device being disposed in an arrangement wherein the media in motion relative to the system can be exposed to the radiation emitted from the points located along the outwardly facing surface of the second infrared media exposure device in rapid -24 -succession to the exposure by the ultraviolet media exposure device and wherein each surface area of the media which is to be exposed can be exposed to radiation emitted from one or more of the points of a particular one of the sets of points of the second infrared media exposure device, the set of points of the second infrared media exposure device corresponding to a set of points of the first infrared media exposure device.
29. A system according to any one of claims 26 to 28, including a media preheating device, the media preheating device increasing the temperature of the media before it is exposed by the first media exposure device.
30. A system according to claim 29, wherein the media preheating device includes a plurality of infrared radiating elements.
31. A system according to claim 29, wherein the media preheating device includes a heated roller.
32. A system according to any one of claims 28 to 31, wherein the points of the first and second infrared media exposure devices, respectively, are substantially equidistantly spaced in a two-dimensional array of which adjacent columns and rows are offset relative to one another.
33. A system according to any one of claims 28 to 32, wherein the radiating elements of the first and second infrared media exposure devices, respectively, are substantially equidistantly spaced in a two-dimensional array of which adjacent columns and rows are offset relative to one another.
34. A system according to any one of claims 26 to 33, wherein the radiation emitted from each point of the first infrared media exposure device has substantially the same radiation pattern.

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35. A system according to any one of claims 26 to 34, wherein the radiation emitted from each point of the first infrared media exposure device has substantially the same amplitude.
36. A system according to any one of claims 26 to 35, wherein the radiation emitted by each radiating element of the first infrared media exposure device has substantially the same radiation pattern.
37. A system according to any one of claims 26 to 36, wherein the radiation emitted by each radiating element of the first infrared media exposure device has substantially the same amplitude.
38. A system according to any one of claims 26 to 37, wherein the first infrared media exposure device includes radiation combination means for combining the radiation emitted by more than one radiating elements corresponding to a point, the combined radiation to be emitted from the point.
39. A system according to claim 38, wherein the radiation combination means is in the form of a polarising beam splitter.
40. A system according to any one of claims 28 to 39, wherein the radiation emitted from each point of the second infrared media exposure device has substantially the same radiation pattern.
41. A system according to any one of claims 28 to 40, wherein the radiation emitted from each point of the second infrared media exposure device has substantially the same amplitude.
42. A system according to any one of claims 28 to 41, wherein the radiation emitted by each radiating element of the second infrared media exposure device has substantially the same radiation pattern.

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43. A system according to any one of claims 28 to 42, wherein the radiation emitted by each radiating element of the second infrared media exposure device has substantially the same amplitude.
44. A system according to any one of claims 28 to 43, wherein the second infrared media exposure device includes radiation combination means for combining radiation emitted by more than one radiating elements corresponding to a point, the combined radiation being emitted from the point.
45. A system according to claim 44, wherein the radiation combination means is in the form of a polarising beam splitter.
46. A system according to any one of claims 26 to 45, wherein the first infrared media exposure device includes infrared radiation modification means for modifying and emitting from the device radiation originally emitted by the infrared radiating elements, each point being defined by a surface area of the radiation modification means from which the radiation originating from the corresponding particular one or more infrared radiating elements emits from the device.
47. A system according to claim 46, wherein the infrared radiation modification means of the first infrared media exposure device includes a tapered bundle of optic fibres of a predetermined length, each fibre having substantially the same orientation and substantially the same tapered profile, the tapered bundle thereby defining a planar wide end and a planar narrow end and being disposed in an arrangement wherein the points are defined along the narrow end of the tapered bundle.
48. A system according to claim 46, wherein the infrared radiation modification means of the first infrared media exposure device includes at least one lens, each lens being disposed in an arrangement wherein one or more of the points are defined by a surface area of the lens, the radiation emitted by the -27 -device from each of the points being focused by the lens at a distance which is within a particular range of distances from the device.
49. A system according to claim 48, wherein the infrared radiation modification means of the first infrared media exposure device comprises a rnacrolens array.
50. A system according to claim 48, wherein the infrared radiation modification means of the first infrared media exposure device comprises one telecentric lens.
51. A system according to claim 48, wherein the infrared radiation modification means of the first infrared media exposure device comprises a microlens array.
52. A system according to any one of claims 26 to 50, wherein the infrared radiating elements of the first infrared media exposure device comprise macro Light Emitting Diodes.
53. A system according to any one of claims 26 to 51, wherein the infrared radiating elements of the first infrared media exposure device comprise micro Light Emitting Diodes.
54. A system according to any one of claims 28 to 53, wherein the second infrared media exposure device includes infrared radiation modification means for modifying and emitting from the device radiation originally emitted by the infrared radiating elements, each point being defined by a surface area of the radiation modification means from which the radiation originating from the corresponding particular one or more infrared radiating elements emits from the device.

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55. A system according to claim 54, wherein the infrared radiation modification means of the second infrared media exposure device includes a tapered bundle of optic fibres of a predetermined length, each fibre having substantially the same orientation and substantially the same tapered profile, the tapered bundle thereby defining a planar wide end and a planar narrow end and being disposed in an arrangement wherein the points are defined along the narrow end of the tapered bundle..
56. A system according to claim 54, wherein the infrared radiation modification means of the second infrared media exposure device includes at least one lens, each lens being disposed in an arrangement wherein one or more of the points are defined by a surface area of the lens, the radiation emitted by the device from each of the points being focused by the lens at a distance which is within a particular range of distances from the device.
57. A system according to claim 56, wherein the infrared radiation modification means of the second infrared media exposure device comprises a rnacrolens array.
58. A system according to claim 56, wherein the infrared radiation modification means of the second infrared media exposure device comprises one telecentric lens.
59. A system according to claim 56, wherein the infrared radiation modification means of the second infrared media exposure device comprises a microlens array.
60. A system according to any one of claims 28 to 58, wherein the infrared radiating elements of the second infrared media exposure device comprise macro Light Emitting Diodes.

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61. A system according to any one of claims 28 to 59, wherein the infrared radiating elements of the second infrared media exposure device comprise micro Light Emitting Diodes.
62. A system according to any one of claims 27 to 61, wherein the ultraviolet radiating elements are substantially equidistantly spaced in a two-dimensional array and substantially co-planar.
63. A system according to any one of claims 27 to 62, wherein the plurality of ultraviolet radiating elements comprises a plurality of macro Light Emitting Diodes.
64. A system according to any one of claims 27 to 63, wherein the ultraviolet radiation modification means is in the form of elongated cylindrical lens, the lens being disposed transverse to the direction of the radiation emitted by the radiating elements.
65. A method of exposing a media of which a surface area contains a photopolymer substance, the colour of the photopolymer substance being determined by the degree of polymerisation thereof, the method including the following steps in sequence for each surface area spot which is to be exposed: exposing the surface area spot to a first series of exposures of infrared radiation within a predetermined time, thereby cumulatively increasing the temperature of the photopolymer substance of the surface area spot to at least a predetermined activation temperature to allow for the polymerisation of the photopolymer substance of the surface area spot on the subsequent application of ultraviolet radiation of a predetermined amplitude and a predetermined duration to the surface area spot; exposing the surface area spot to the ultraviolet radiation of the predetermined amplitude and the predetermined duration; and -30 -exposing the surface area spot to a second series of exposures of infrared radiation within a predetermined period of time, thereby cumulatively further polymerising the photopolymer substance of the surface area spot to a degree determined by the required colour of the surface area spot.
66. A method according to claim 65, wherein the shade of the colour of the photopolymer substance of each surface area spot is determined by the degree to which the temperature of the photopolymer substance of the surface area spot is increased above the activation temperature before the polymerisation of the surface area spot.
67. A method according to claim 65 or claim 66, wherein the media is pre-heated to a predetermined first temperature which is lower than the activation temperature.
68. A method according to any one of claims 65 to 67, wherein the first series of exposures comprises a predetermined number of exposures of a predetermined amplitude and a predetermined duration.
69. A method according to any one of claims 65 to 67, wherein the first series of exposures comprises a predetermined number of exposures, each of the exposures having a predetermined amplitude and a predetermined duration.
70. A method according to any one of claims 65 to 69, wherein the second series of exposures comprises a predetermined number of exposures of a predetermined amplitude and a predetermined duration.
71. A method according to any one of claims 65 to 69, wherein the second series of exposures comprises a predetermined number of exposures, each of the exposures having a predetermined amplitude and a predetermined duration.

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72. A media exposure device substantially as herein described and/or as illustrated with reference to the accompanying drawings.
73. A system for exposing a media substantially as herein described and/or as illustrated with reference to the accompanying drawings.
74. A method of exposing a media substantially as herein described and/or as illustrated with reference to the accompanying drawings.