EP4031298A1

EP4031298A1 - Recycling of flat panel displays

Info

Publication number: EP4031298A1
Application number: EP20824079.6A
Authority: EP
Inventors: Arthur MIDDLETON; Brian Sheehan; Cian MC LOUGHLIN
Original assignee: Peregrine Tech Holdings Ltd; Peregrine Technologies Holdings Ltd
Current assignee: Peregrine Tech Holdings Ltd; Peregrine Technologies Holdings Ltd
Priority date: 2019-09-17
Filing date: 2020-09-16
Publication date: 2022-07-27
Also published as: GB201913410D0; WO2021053026A1

Abstract

The present invention concerns the field of safe disposal or recycling of devices which include backlit LCD flat panel displays (FPDs) such as televisions, public information screens and signs, advertising panels, computer monitors and lap-tops, tablets and computers with integrated flat panel displays (100). The disclosure provides a process for the disassembly of backlit LCD FPDs which each comprise a Liquid Crystal Display screen which occupies a front face of the FPD and a housing (101) which accommodates the LCD screen (103), with backlighting means (300) disposed adjacent a backside of the LCD display screen to provide illumination, the housing including a front border region which serves as a frame around the LCD display screen, wherein the method comprises: (i) providing an end-of-life waste FPD, (ii) conveying the FPD to a cutting station and cutting directly into the exposed LCD display screen along cutting paths which are offset inwardly from the front border regions (102), so as to create a generally rectilinear sub-unit (113) of the LCD display screen within the screen border region, (iii) causing or allowing the screen sub-unit to become detached from the screen border, and setting aside or conveying the screen sub-unit for storage, disposal or further processing, and (iv) conveying the FPD chassis remaining after sub-unit detachment to a treatment station, and removing the backlighting means in the housing rendered accessible by removal of the screen sub-unit.

Description

Recycling of Flat Panel Displays

The present invention concerns the field of waste recycling, especially recycling of electrical and electronic goods. The invention relates in particular to the processing of devices which include LCD flat panel displays (FPDs) such as televisions, public information screens and signs, advertising panels, computer monitors and lap-tops, tablets and computers with integrated flat panel displays.

Such FPDs have displaced cathode ray tube (CRT) displays and now form a significant waste stream in domestic and commercial waste. Several types of FPD are known. For example, there are simple liquid crystal displays (LCDs), backlit LCDs (with LED backlighting), plasma screens, organic light-emitting diode (OLED) screens, amongst others. With improvements in the technology screens rapidly become obsolescent as colour rendition and screen resolution improve, and imaging codecs change. Thus, more FPDs enter the waste stream as technology improves.

With such a change in global FPD markets the traditional methods of disposal (such as simple shredding) create environmental and economic challenges. With a declining CRT market and a growing FPD market (4200 million per year) a different approach to recycling is required. There is WHO legislation on the exposure of individuals to hazardous materials such as those contained within the FPD. These levels are specified on a per county basis under the health and safety and welfare legislation. With this understood, high throughput methods of processing FPDs is a requirement. Various companies exist in the market such as Blue box, Erdwich, ALR and MRT that provide different solutions for shredding and or cutting of FPDs.

Regulatory initiatives such as the European Commission’s WEEE Directive (2012/19/EU) have directed that landfill dumping of electronic goods (including TV sets) be strictly limited, and recycling and repair encouraged. Manufacturers are obliged to finance a proportion of the collection, treatment and recovery costs of end-of-life electrical goods, including those which incorporate FPDs, based upon market share of the relevant class of goods. Special provisions exist for screens and monitors having an area of greater than 100 cm², including use of best practice in treatment and disposal of hazardous material, and reporting weight of products processed. Provisions which require cycling and treatment of electrical waste exist or are being developed in many other regions or countries worldwide, including states in Australia, Asia and the US.

US2005/0159068 discloses a method of recycling flat panel displays, in particular to permit re-use of the glass by removing lead-containing components. The display panels include two glass plates, which are separated by cutting, dissolving or melting the frit glass that joins them. This method clearly relates to plasma screens, as only these have the requisite lead content.

WO201 1/073966 discloses a process for removing hazardous material from LCD displays backlit by cold cathode fluorescent tubes (CCFTs) and, in particular, separating the mercury contained in such tubes. This method involves cutting through the front of the housing which provides a border around the viewing screen. This is said to permit removal of the entire LCD panel and access to the tubes behind. These glass tubes are crushed to liberate the mercury-containing fluorescent gas, which is sucked into a collection device. The LCD screen cutting takes place indirectly, through the frame which defines the border of the housing, and then into the edge region of the LCD screen panel. The present inventors have found that if the LCD screen has little overlap behind the border, the cut may fail to detach the LCD screen from the chassis in which it is mounted because the screen panels are usually held in place at the edges thereof. Thus the LCD panel may remain attached to the FPD after the cutting process, at least partially. This means that a costly further step of detaching the screen panel from the housing is necessary, and this may have to be done manually. The present invention seeks to address one or more of the aforementioned problems with prior art processes and to provide a more efficient processing of end-of-life backlit LCD displays.

According to one aspect of the present invention there is provided a process for the disassembly of backlit LCD flat panel display units (FPDs) which each comprise a Liquid Crystal Display screen which occupies a front face of the FPD and a housing which accommodates the LCD display screen, with backlighting means disposed adjacent a backside of the LCD display screen to provide illumination, the housing including a front border region which serves as a frame around the LCD display screen, wherein the method comprises:

(i) providing an end-of-life waste FPD,

(ii) conveying the FPD to a cutting station and cutting directly into the exposed LCD display screen along cutting paths which are offset inwardly from the front border regions, so as to create a generally rectilinear sub-unit of the LCD display screen within the screen border region,

(iii) causing or allowing the screen sub-unit to become detached from the screen border, and setting aside or conveying the screen sub-unit for storage, disposal or further processing.

The method may further comprise: (iv) conveying the FPD chassis remaining after sub-unit detachment to a treatment station, and removing the backlighting means in the housing rendered accessible by removal of the screen sub-unit.

The backlighting means may comprises one or more CCFL tubes. The removal may comprise dislodging and/or breaking the CCFL tubes. The broken or dislodged CCFL tubes may then be collected for safe disposal or further treatment. This includes the CCFL tubes thereby detached and/or any tube debris. The backlighting means may comprise a plurality of LED lighting units. In this case the removal comprises dislodging the lighting units. The dislodged units are preferably collected for disposal or further treatment.

By cutting directly into the LCD screen, inwardly of the border provided by the FPD housing, it is ensured that all or most of the visible portion of the LCD can become detached from the FPD. By cutting directly through the visible part of the screen panel, inwardly from of the border, an LCD screen sub-unit is created which cannot still be attached at its edges, as there are cut through. The sub-unit is simple to remove and typically falls away from an inverted FPD unit. While this leaves behind a frame of LCD screen material, this is usually small in amount and weight - typically 7-12 wt% of the overall LCD screen weight. The cutting paths will typically cross the perpendicular screen borders at opposite ends of the paths.

The disassembly process of the invention can alternatively be considered a method for removing hazardous material from backlit LCD displays. The basic process steps are essentially the same.

The cutting process of the present invention provides a significant improvement in the processing, and by avoiding further processing to detach partially attached screens, facilitates automation of the process by use of robots and/or automated tool stations. The process of WO2011/073966 involves indirect cutting and is carried out blind because the LCD screen edge cannot be seen under the border before cutting commences.

The FPD is preferably conveyed to the cutting station so as to arrive in a face down orientation. Conveying may be manual, by an operator, but will typically be by means of a conveyor such as a belt table, trolley or shuttle amenable to automated feed of FPDs.

The cutting station may comprise at least one saw tool or milling tool for cutting the screen. One example of a suitable milling tool is a router. Preferably the cutting station comprises a first saw tool and at least one further saw tool for cutting the screen. The respective first and further saw tools may be adapted to have generally parallel cutting paths separated by a span distance. In a preferred arrangement, the first saw tool is fixed in position and wherein the further saw tool is adapted to travel with respect to the first cutting tool. This permits a variation in the cutting span to a predetermined distance depending upon one or more dimensions of the FPD screen to be cut. With a larger screen the spans will be set to be wide, whereas with a smaller screen the span will be less wide.

In an alternative cutting arrangement a single milling tool, such as a router, may be provided and controlled to follow a generally rectilinear path when cutting the FPD screen. A robot arm may be used to perform this. This avoids having to rotate the screen between cuts, or the need to provide two sawing tools operating in parallel or at 90 degrees with respect to one another.

In the process the FPD is preferably delivered to the cutting station in a face down orientation, with the cutting blades extending upwards to effect cutting of the LCD screen. The cut-out screen sub-unit may then fall under gravity into, or down a ramp, into a collection bay or bin.

In another aspect of the invention the cutting station may be provided with means for rotating the FPD about a vertical rotation axis, or for rotating the orientation cutting tools with respect to the FPD. Thus, after cutting of the LCD screen along paths in a first direction the screen may be rotated to allow cutting (using the same tool or tools) of the screen along paths in a second direction perpendicular to the first direction. These two pairs of parallel cuts produce the said generally rectilinear sub-unit of the LCD display screen. The means for rotating preferably comprises a robot arm, but could comprise a turntable. Alternatively, a second pair of cutting tools could be provided for cutting in the perpendicular direction, without rotating the FPD. The FPD can be held immobile while a robot arm equipped with a cutting tool provides said two pairs of parallel cuts. In yet another aspect of the invention an FPD characterisation station is provided in advance of, or at, the cutting station. The characterisation station being adapted to obtain or retrieve appropriate cutting path information for the particular FPD, for use in the cutting station. The cutting path information for a range of known FPDs may be stored in a database associated with a data processing system. Each FPD entry in the database includes one or more characterisation variables associated with the FPD. These are stored in the database, so that an obtained characterisation variable may be compared with the stored variables so as to identify a matching stored FPD, or closest match to a stored FPD, or in the absence of these, a null a result.

In a further aspect of the invention, the characterisation station comprises a weigh station adapted to weigh the FPD. This provides a measured weight value for the FPD. This weight value may be sent to the data processing system. Here the measured FPD weight value may be compared with the associated database which comprises known FPD weights, so as to obtain one or more candidate FPD matches based upon identical weight, or closest, weight. This allows the determination of the appropriate cutting path information for use in the subsequent LCD screen cutting, based upon stored screen dimension information for each FPD present in the database.

In yet a further aspect of the invention, the FPD characterisation station comprises an optical scanner. The optical scanner is adapted to measure one or more dimensional variable of the FPD. Typically this will be an externally visible dimension variable. The variable may comprise one or more of: FPD housing width and or length and/or diagonal extent, LCD screen width and/or length, and/or diagonal extent. Other variables may be included to provide a cross check, such as housing depth. Preferably the scanner is a 3D scanner which provides X, Y and Z axis information.

The dimension variables may be combined with weight measurements to provide a more accurate, or rapid, characterisation of each FPD. The dimension variable or variables may be compared to corresponding known FPD dimension variables provided in the database. This permits matching based upon identical, or closest, dimension variable(s), with the appropriate cutting paths thereby being retrieved from the database entry for the identified FPD.

In a particular aspect of the invention the optical scanner measured dimension variable(s) concern the disposition of the LCD screen area within the front face of the FPD, so as to determine appropriate cutting paths directly from the FPD itself. This obviates the need for a stored database of FPD cutting paths, or, alternatively, permits a cross-check or confirmation of the stored values in a database (when available).

This ‘on the fly’ determination of cutting paths may be invoked when a null match, or failure to get a closest match within an acceptable tolerance value, is obtained from the comparison with the database of FPDs, so that the FPD is determined to be unknown. Upon determination of an unknown FPD, the data processing system may establish a new database entry which is populated with characterisation variables and/or appropriate cutting paths.

One or more of the characterisation variables and/or cutting paths may be obtained from the characterisation station. Alternatively, or in addition, one or more of the characterisation variables and/or cutting paths may be obtained manually by prompting a human operator to perform one or more of the characterisation measurements and/or derive the cutting paths, and enter these into the database.

In one more aspect of the invention the FPD is provided with an optical identifier, such as a, brand, QR code, serial number or barcode or hologram or the like. This would typically be present on an external surface of the FPD and the characterisation station comprises an optical identifier reader. By serial number we include alphanumeric combinations in general. The barcode may be two dimensional, or three dimensional. So the optical identifier reader may comprise an optical character recognition (OCR) vision tool for reading the serial number; or may comprise a barcode reader vision tool for reading the barcode. These may be included in the optical scanner system and software, or provided as one or more stand-alone sub-stations. A simple camera may be provided to obtain an image of the identifier from which a serial number or barcode is extracted using suitable software.

Typically, the optical identifier reader obtains the identifier from the FPD and matches the FPD with one of a pre-populated database of said identifiers. The database including FPD dimension and/or cutting path information to be used in the cutting station (as explained above).

The identifier may comprise a product make (i.e. brand) and model number (alphanumeric, or numeric) which is unique to that product or indeed production run.

In a particular aspect of the invention there is provided a process as hereinbefore described, wherein the identity of each FPD processed is logged by the data processing system. This provides an audit of FPD makes and models processed over time. This is an important and useful feature because regulatory requirements require FPD manufacturers to be responsible for recycling and reprocessing of FPDs, with costs payable when this process is carried out by a third party processor.

The dislodgement and or detachment of CCFL tubes may be conducted by a router tool at the tube treatment station. Other tools such as mechanical brushes, grinders, crushers, flails, levers or probes could be used. The CCFL tubes are typically held at opposite ends in clasps (including electrical contacts). Further ties or clamps may be used to hold long tubes in place. The clasps and clamps are typically disposed on the front face of a back plate within the FPD housing, behind the LCD screen, especially in TV sets. In monitors and lap top screens a single pair of CCFL tubes may be present disposed parallel and spaced apart along opposite screen edges. In another particular aspect of the invention a first robot arm may be provided. This may be provided between the cutting station and the treating station. The arm is suitable for holding and translating the FPD up to, or past, the optical scanner, or for lifting the FPD chassis from the cutting station.

This arm may then hold the FPD chassis at an orientation and location suitable for routing to take place at the treating station. The location is generally over a hopper or chute positioned at the tube treatment station so that tubes and tube debris falls into the hopper or chute from the FPD chassis. The collected tubes or tube debris may be conveyed into a shredder or crusher-compactor. Conveniently this may be located below the hopper or chute, to take advantage of gravity feed.

The crushed tube material maybe used to fill storage containers which are hermetically sealed for disposal or further processing. The tubes are typically contaminated with poisonous mercury, so must be isolated safely to avoid hazard.

In a further preferred aspect of the invention the detachment/destruction of CCFL tubes is carried out by a further robot arm equipped with the detachment/destruction tool. Preferably the tool is a router which is provided on a free end of the robot arm. The routing may take place by scanning the router incrementally back and forth across the aperture defined by removal of the LCD screen sub-unit. This impacts the CCFL tubes disposed behind the removed screen sub-unit.

So in a typical process, the first robot arm holds the FPD chassis face-down over the hopper or chute, preferably in an inclined orientation of 10 to 80 degrees from the vertical. The router (or equivalent) tool detaches or destructs any tubes so that any removed tube material falls directly into the hopper or chute below. The incline ensures that the material falls in a controlled way over the ledge defined by the lower edge of the FPD. An optional step is to use a camera on the second robot arm to quality check the chassis for complete backlight removal prior. If this quality control step is failed then the chassis is reprocessed to remove remaining backlight material.

After removal of the CCFL matter, the first robot arm places the FPD chassis onto an exit conveyor for further downstream processing, subsequent storage, recycling or disposal.

The whole process is typically carried out using apparatus located in a controlled room (HVAC) environment which removes air entrained hazardous particles or gases.

Preferably, the process apparatus incudes an air extraction system in which extraction vents are provided in the region of the screen cutting station and/or the conveyer. Air-entrained debris ejected by or from the screen cutting and or conveyer or crusher /shredder is extracted from the cutting or routing locations and accumulated for disposal or recycling. At the routing station a blower may be provided to blow air onto the FPD back panel which entrains surface particles and hazardous dust into an airflow which moves contaminated air away from the routing process.

In an alternative aspect of the invention the process set out above may be modified to provide for disassembly of LCD FPD computer monitors or tablet or laptop screen units as follows:

There is provided a process for the disassembly of backlit LCD flat panel display units (FPDs) which each comprise an LCD screen which occupies a front face of the FPD and a housing which accommodates the LCD screen, with backlights for illuminating a back side of the LCD screen, the backlights comprising at least one CCFL tube disposed at one end region of the housing and at least one further CCFL tube disposed at an opposite end region of the housing, with a light guide plate disposed between the CCFL tubes to provide the back side illumination, the housing including a front border region which serves as a frame around the visible LCD screen, wherein the method comprises: conveying one of said LCD FPDs to a cutting station and cutting into the exposed LCD display screen along two substantially parallel cutting paths which are offset inwardly from the opposite end regions of the housing which contain the CCFL tubes, the cuts being sufficiently deep to completely remove the said end regions of the housing with the CCFL tubes contained therein, so as to produce two end region units and a screen sub-unit comprising the majority of the LCD screen, collecting the two end regions for subsequent treatment of the CCFL units and conveying the LCD screen sub-unit for storage, disposal or further processing.

The subsequent treatment of the CCFLs may comprise removal of hazardous mercury-containing gas.

Following is a description, by way of example only, of one mode for putting the present invention into effect, with reference to figures of the accompanying drawings in which:

Figure 1 is a front view of a typical backlit LCD TV set to be recycled in accordance with the present invention.

Figure 2 is a schematic transverse cross-sectional view through the LCD TV of figure 1 (not to scale).

Figure 3 is another schematic transverse cross-sectional view through an LCD monitor that is backlit using two CCFLs and a light guide plate.

Figure 4 is yet another schematic transverse cross-sectional view of an a backlit LCD TV with an array of LED backlights.

Figure 5 shows the backlit LCD TV of figure 1 with the position of cutting lines projected onto the front face of the screen. Figure 6 is a schematic transverse sectional view of the TV of figures 1 and 2, shown after cutting and removal of a screen sub-unit by the method of the present invention.

Figure 7 is a top view of apparatus used in carrying out the method of the present invention.

Figure 8 is a perspective view of the same apparatus.

Figure 9 is a perspective view of the apparatus located in an isolation cell or room.

Figure 10 is a flowchart of the processing steps involved in processing a backlit LCD TV displays.

Figure 11 is a schematic transverse cross-sectional view through a monitor LCD with backlighting provided by two CCFLs and a light guide plate, as shown in figure 3, with cutting directions indicated.

Figure 12 is a flow chart of the processing steps involved in processing LCD monitors of the type shown in figure 11.

The present invention facilitates the use of a fully robotic (automated) system to depollute FPDs. It permits the identifying and weighing of the FPD and capturing the data. The data may be used to select the appropriate processing technique for each individual type of FPD. The process involves removing the visible screen by cutting it out of the frame. This allows access to the backlights which are removed at the routing station with a robot to remove the lights and holders for the FPD. The waste glass/backlights from the routing may be compressed by shredded before it enters the storage bins. The process equipment is usually freestanding inside a clean room environment with carbon filtration.

The FPD screens are typically removed (cut out) in downward facing position. For TVs, the optical scanner finds the screen bezel and then cuts 0-12mm into the screen side of the bezel to a depth of 0-20mm.

For the processing of LCD computer monitors the cut is a ‘full liberation cut’ to remove the entire border regions typically by cutting to a depth of 40 -100mm through the entire monitor depth. The cuts are made 0-100mm inward from the top of the FPD. The cuts in the screen are made using readily available blades with inserts designed for cutting and/or grinding depending on the process.

Efficient processing in accordance with the present invention involves having access to an accumulation of end-of-life FPDs, typically back-lit LCD TV sets or computer monitors, as described in more detail hereinafter. These may be provided as discrete batches sourced from a waste processing plant, or as a generally continuous stream when the apparatus is integrated into an electrical waste processing plant.

As a preliminary step each FPD unit may be characterised by measuring its weight and/or by using other identifying characteristics such as dimensions.

So the underlying method may include:

- Identifying (e.g. by weight) the FPD type.

- Cutting to liberate the screen of the FPD from the chassis

- Depollute FPD and removing of backlights (and typically the associated holders) in the FPD.

Preferably we cut into the screen of the FPD leaving a border of LCD screen left like a picture frame within the FPD. This differs from previous methods which typically cut around the LCD screen so as to leave it intact. Cutting within the perimeter of the screen facilitates the removal of the screen, as it is usually attached to the FPD screen in the edge regions. Hence in the present method the screen typically falls away from the FPD chassis after cutting. In one embodiment of the method, after the FPD is brand and model identified by weight it is then picked-up from a datum corner position on the weigh station using a robot arm.

A 3D scanner may be used to log the dimensions and screen position so as to inform the subsequent processing cuts or machining.

The cuts may be made so as to leave a border 3-20mm thick of the LCD (glass) screen in the FPD, in the manner of a picture frame. This avoids the need (in prior art processes) to cut into the surrounding support frame or housing of the FPD.

Once the screen has been cut and the inner portion removed the LED back lights or CCFL back lighting tubes may be removed by a tool, such as a router. Preferably this is done using a robot with sensing technology for controlling location and proximity to the back pane of the TV and the CCFL light tubes or LED array. The FPD may be held by the arm at an angle to the ground allowing for the collection of debris in a hopper. This could also be complete by a static tooling station.

The liberation of the CCFL tubes and tube holders is achieved using a mill like cutting tool designed for this purpose, such as a router.

The apparatus will typically use two robots, one equipped with a grasping tool for lifting and moving (translating) the FPD between weighing station and routing station where the backlights (CCFLs or LEDs) are removed. The apparatus can be scaled by increasing the number of FPD feed streams and robot arms.

Offcuts which still hold CCFL tubes or pieces may be further treated by shredding these offcuts along with the liberated CCFL tubes.

The cutting robot may be provided with (or have associated therewith) air nozzles which blow at the FPD while the cutting process in underway, so as to disperse the tube contents. The nozzles may be adjacent suction ducts for removing harmful gas or air-entrained particles arising from the cutting.

The collection of FPD as an end of life waste product means many of the FPDs are damaged and 3D scanning can identify damaged FPDs and take the damage into account, or invoke manual processing if the damage is too severe for an automated process to continue.

It may be necessary to manually identify and select the FPD type in advance of processing. This is important because monitors without back lighting may require a different process to backlit TVs, and may require different cutting tools and gripper tools.

The infeed conveyer feeds the FPD into the machine with the screen facing down. At the end of conveyer it reaches the identification and weighing station where the FPD is lifted to assess weight and read for make and model of FPD. It is gripped in a screen down orientation by the grip end of a robot arm arm.

The FPD may be 3D scanned before the arm moves the FPD to the screen cutting station. The arm positions the FPD face down on the screen cutting station. The 3-D scanner reads high differences, housing size, and shape and allows for damage by comparing a damaged element with a template example stored in the data processing system.

Once picked-up, the end of the robot arm effector (grip) senses the grip finger position to insure the FPD does not distort. In the event of unexpected distortion the grip may be adjusted or removed and re-applied to obtain a better grip. Since the screen is the lowest area on the viewing face (LCD screen) of the FPD, this is cut first by cutting blades (wheels) which project upwards. The two longitudinal (X) and transverse (Y) cuts leave a picture frame of about 0-15mm of screen within the FPD. The cuts extend to a depth of about 5-100mm, depending upon the particular FPD. As the screen is face down (screen down) while being processed allowed for any debris to be captured by dropping down under gravity from the cutting location. Debris may be collected under the cutting station.

In the cutting station one blade may be in a fixed position and the other moveable in the width direction so as to alter the cutting span. A conveyor may be used to feed the FPD into the cutting wheels to produce parallel elongate cuts. The FPD is fed through the screen cutting station by the robot in the manner of a table saw with the short edge leading and once this is cut is complete the robot raises up and rotates the FPD though 90 degrees to cut the long side. The blades may have a fixed height so that they do not travel in the Z. direction.

The liberated screens fall into a chute underneath the screen cutting station and then slide onto the screen outfeed conveyor. Any broken tubes caused by the screen cutting at this stage will fall through a gap between the chute and the conveyor and be diverted to the lamp shredder.

The tube shredding is conducted in a conventional shredder placed over the tube bins. A robot router is used to break the lamps for compaction and easier transport. They are removed by the robot from the FPD using a routing tool on the robot arm.

The circular saw blades vary in size from about 150mm to 480mm diameter and RPM from 2500 to 10000. The blades may be adapted for cutting or grinding.

In the process the screens are liberated from the FPD in the screen cutting station while being held by the end effector of the robot. This allows access to backlights by the robot arm for further processing (to removed remnant CCFL tubes) if required. The screen is held at an angle of between about 10-80 degrees off vertical. The routing robot routes out the backlight and holders from the FPD using a cutting tool. If fitted with hot and/or cold air systems, these assist in the dispersal of the debris into suitable collectors. So the CCFL tubes or shreds fall into the hopper to be fed into the shredder to be broken into particles. The shredders feed bin storage containers with an hermetic seal which allows them to be transported safely for disposal or recycling. This ensures that the mercury containing hazardous waste is separated from the other machining dust and waste generated within the process apparatus by the cutting/routing.

Data from the FPD processing is logged and may be stored on the data processing or kept in the cloud for ease of remote access. The data logs each recycling event and, so far as is possible, the make and model of each FPD that is processed. This facilitates the accounting for reprocessing of electrical goods required by regulatory regimes in which manufacturers of FPD screens are responsible for contributing for recycling costs, so recyclers will be reimbursed for their re-processing. So the data stored is accounted for on a per FPD/TV as well as recording the overall numbers on a holistic level.

The entire process may be carried out in clean room environment using a HVAC system in which ducts exhaust emissions to the environment through a specifically designed carbon filtration system.

The use of robots allows us to automate the process and minimize human intervention within the machine. The speed of the process varies with FPD size from about 15 to about 80 second per FPD. LED displays are processed quicker and backlit CCFL and monitors quicker are than TV’s. The FPD size also has an impact on timing of processing speed. This is a two step fully robotic process. This is not a recycling process it is depollution process to enable the next step of material separation before the components are eventually recycled as secondary raw material. After the depollution the FPD is ready for further processing.

Specific embodiment

A first TV set is shown generally as 100 in figure 1. The TV set comprises a rectilinear housing 101 which forms a perimeter frame 102 around an LCD panel 103 which serves as the viewing screen. A lower end region of the housing is provided with a stand 104 which includes a horizontal base plate 105 which supports the TV set when in use.

In figure 2 sidewalls 106 and 107 and housing back 108 are shown. The LCD panel 103 sits behind the frame 102 and overlaps the underside regions of the frame. Under the LCD panel is a Perspex protective stratum/diffuser 109. Under the stratum is an array of generally cylindrical CCFL tubes 110 arranged parallel and extending longitudinally from side to side across the set. The tubes are accommodated in a metal reflector tray or back plate 111 at attached thereto by plastic retainers (not shown) Under the tray is a RGB layer 112 attached to an inside surface of the housing back 108.

A backlit FPD monitor / laptop screen unit 200 arrangement is shown in figure 3, in which like elements are given corresponding numbering, but prefixed with a 2 rather than 1. . Of note is that there are only two (somewhat larger) CCFL tubes 210 at spaced apart and parallel at opposite ends of the reflector tray 211. Certain models of monitor have pairs of tubes at each opposite end region. The tubes are located and held by plastic retainers (not shown). A Perspex plate 216 extends between the two spaced apart CCFL tubes 210 acts as a light guide/tube for electromagnetic radiation emitted from the tubes. The plate is provided with an upper surface treatment which guides light to emit upwards towards the diffuser and screen 203. This provides uniform illumination so as to provide indirect backlighting of the LCD panel from the CCFLs via the light guide.

In figure 4 and LCD FPD backlit using LEDs is shown generally as 300. As before, like feature are given like numbers, but in the 300 series. Instead of CCFL tubes, this FPD uses LEDs as the light source for backlighting.

In figure 5 the FPD of figures 1 and 2 is shown with the location of cutting paths indicated by the parallel pairs of ghosted lines V1 ,V2 and H1 , H2. The cutting paths define therewithin a sub-unit 113 of the LCD screen 103, which sub-unit is within the border or bezel 102 of the screen housing. Process and apparatus

In a specific embodiment of the present invention a recycling apparatus for flat panel display units is shown generally as 10 in figure 7. As an initial step end of life backlit LCD TV sets or monitors are stripped of any appendages such as external cables and loose stands. The remaining FPD unit (such as those described above with reference to figures 1 to 4) is then manually loaded, screen panel down, and aligned square-on to an elongate inlet feed conveyor 11 comprising a moving conveyor belt 12 which transports the FPD in a longitudinal in feed direction of travel (arrow A).

The conveyor feeds to a weigh station 13 having a series of transverse weigh members 14. The FPD abuts a corner stop which corresponds to a weighing position. The weigh members are then shifted to project upwards to lift the FPD so that the weight is taken by the weigh members and can then be derived from associated pressure sensors/cells (not shown). The weight (+/- an acceptable tolerance) may give a single FPD match, or a set of possible TVs/monitors. An optical scanner 19 is a 3-D scanner which is used to further characterise the FPD. So the set of possible FPDs can be reduced by using the scanner to measure one or more dimensions. If a match is made then pre- loaded processing data and parameters for that set may be invoked to facilitate the subsequent processing.

For example, in identifying a specific TV set, the weight information is communicated to a data processing system server (see control system 30 in figure 8) which includes a stored look-up table of TV sets/monitors by weight.

If several candidates are identified the data processing system invokes a dimension measurement step, which is then carried out on the weighing station by using automated calipers or clamps which span the height and/or width of the TV to measure these. Alternatively the scanner may be used to derive dimension information. This then allows a further look up table of TV dimensions to be used to identify a candidate TV set. The pre-loaded processing data and parameters are used to guide the following cutting and routing operations, so that they may be automated according to predicted dimension and configuration data for each TV set. If the set is not identified a manual process may be invoked with the TV brand and model being logged manually by an operator. The appropriate cutting and routing positions and extents are logged when carried out with the robot arms under manual control. This tool operation data is stored for use to allow automation of the processing of the ‘new’ TV set in the future, with the look-up tables updated appropriately to reflect the newly entered TV set/monitor. The weight value and a sequential identifier code for the FPD are sent to a data processing server in the control system 30 and stored.

An FPD handling robot arm 15 is provided attached to a frame 16 located adjacent the weigh station end, as shown in the figure 8. The robot arm 15 is provided with a turntable base 17 and various articulated joints 18, and a gripper claw 31 for picking up a free corner region of the FPD. The robot is pre-programmed to approach a suitable portion of the FPD housing, such as a corner region, and apply controlled pressure so as to grip but not crush the FPD . The arm then sweeps the FPD past the optical scanner 19. The scanner measures screen panel height and width, and location with respect to any perimeter frame or bezel of the FPD housing. The data processing system stores the dimension data necessary to be able to isolate the screen panel’s location and extent with respect to the gripper position. Should the scanned data not correlate with the pre-loaded data it may be assumed that the FPD is damaged, and it is therefore rejected from further processing by the apparatus and sent for manual processing.

The gripper may include pressure sensors. Should a sudden reduction in pressure be felt, corresponding to mechanical compromise or crushing of the FPD, then the FPD is rejected from further processing and placed by the robot arm onto an outfeed conveyor 20. An alert signal is generated by the data processing system so as to prompt the intervention of an operator who will decide how best to treat the FPD by alternative measures (such as manual disassembly). Having established the screen size, weight and location on the FPD front surface, the robot arm transports the FPD to a cutting station 21. The cutting station has first and second spaced apart rotary cutting saws 22,23. The first and second saws are aligned coaxially and define therebetween a cutting spacing and parallel cutting lines. The second saw 23 is mounted on a traveller 24 so that the saw separation may be varied by travel towards or apart from the first saw blade 22. The data processing system selects a cutting separation corresponding to the desired cutting width or height dimension of the screen panel, or a short distance under this.

The FDP unit is placed face down on the cutting table 25 which is mounted on the frame at an angle of greater than zero and less than 45 (about 30 degrees) from the horizontal. The cut is made by the robot arm translating the screen in a cutting direction, over the cutting saws from one edge region of the FPD unit to the opposite side. The cut depth is usually set to cut through the screen panel thickness and plastic diffuser sheet/films, but not so deep as to shatter the CCFL tubes (if present) behind the screen panel. Once a first cut has been made the FPD is rotated 90 degrees by the robot arm and a second pair of cuts are made, perpendicular in direction with respect to the first cuts. In this way a unitary rectangular cut-out sub-unit 113 (figure 5) of screen panel 103 is produced. Having made the cuts, the robot arm lifts the FPD unit from the table 25, leaving behind a cut-out rectangular glass screen panel and plastic diffuser panel and or protective sheeting/films (underlying the screen) on the table. The slope allows the cut-out panel (and any attached diffuser panel or films) to slide away down onto an outfeed conveyor 26, shown in figure 7. The glass panel is then subject to further processing (not shown), and recycling elsewhere.

In the event that CCFL tubes are present the first robot arm is instructed to move the FDP chassis unit to a position above a hopper 27 located to one side of the cutting table and out feed conveyor, as shown in figure 8. The hopper feeds into a shredding rotor (not visible) which in turn feeds (via an Archimedes screw) into a waste crusher/compactor/shredder 29. The compactor includes collection bins 40 which are removable for safe disposal or further treatment.

A second robot arm 31 is provided on an opposite side of the hopper. The arm has a turntable base 32 and articulated joints 33. A distal end of the arm is provided with a router tool 34. The router tool is then directed by the control system to move in inside the cut-out aperture left by the removed screen panel so as to shatter CCFL tubes and displace any associated retaining mounts and tube ends. The FPD unit is angled so as to present the cut-out aperture to the second robot arm router, but also to ensure that routed pieces of the CCFL and retainers etc. fall down into the hopper under gravity. The CCFL pieces will typically be contaminated with mercury and phosphate and are therefore further crushed and compacted, and then collected in the bins 40 (UN certified contaminant containers) which may be hermetically sealed for transport, decontamination or further treatment.

The remaining FPD unit carcass - comprising housing, PCBs/electrical components and internal chassis frame is (after the routing is complete) placed flat onto a carcass outfeed conveyor 35 which is positioned to have one end adjacent the base of the first robot arm and the opposite end adjacent, but spaced apart from, the infeed conveyor. In this way a single person may deal with manual FPD unit feeding-in and collecting out-fed FPD chassis due to the proximity of conveyors.

Once the chassis is placed on the outfeed conveyor, the data processing system is configured to alert an operative of the FPD type and status, so that it is removed to the appropriate location for any further processing or disassembly.

The apparatus is typically disposed within a ‘clean room’ or other containment enclosure within a larger work space, as shown in figure 9. The infeed conveyor 11 , collection bins 40 and outfeed conveyors 26,35 are disposed so as to be accessible from outside the enclosure, via curtained apertures. In normal use there would be no reason for a person to enter the processing area inside the enclosure, so reducing the risk of mercury contamination and hazard from cutting or routing dust. As an additional measure, forced extraction of air from the enclosure takes place via a filtration system (not shown) so as to prevent escape of mercury to the atmosphere outside the enclosure.

The above method is particularly appropriate for CCFL backlit FPD TV sets. It can also be used to process LCD FPD TV sets which are backlit by LEDs. The process is summarised in the flow chart shown in figure 10.

For computer monitors with backlit LCD screens 203 the internal arrangement often relies upon indirect illumination using a light guide panel 216, as shown in figure 3. In this case, rather than cutting out a portion of the LCD screen panel (as described above), the end regions containing the CCFL tubes can be completely cut off using one pair of parallel cuts C1 , C2 in figure 11. The CFFL tubes inside the cut-off edge regions will be intact if the cut is positioned appropriately. These end regions can then be conveyed out of the enclosure for further treatment. Alternatively they can be placed into the shredding hopper and the FPD carcass/chassis with remaining central screen portion placed on the outfeed conveyor 35.

The above monitor processing method is summarised in the flow chart figure 12.

Claims

1. A process for the disassembly of backlit LCD flat panel display units (FPDs) which each comprise an LCD screen which occupies a front face of the FPD and a housing which accommodates the LCD screen, with backlighting means disposed adjacent a backside of the LCD screen to provide illumination, the housing including a front border region which serves as a frame around the LCD screen, wherein the method comprises:

(i) providing an end-of-life waste FPD,

(iii) causing or allowing the screen sub-unit to become detached from the screen border, and setting aside or conveying the screen sub-unit for storage, disposal or further processing,

(iv) conveying the FPD chassis remaining after sub-unit detachment to a treatment station, and removing the backlighting means in the housing rendered accessible by removal of the screen sub-unit.

2. A process as claimed in claim 1 wherein the backlighting means comprises one or more CCFL tubes, and the removal comprises dislodging and/or breaking the CCFL tubes and collecting the CCFL tubes thereby detached and/or any tube debris.

3. A process as claimed in claim 1 wherein the backlighting means comprises a plurality of LED lighting units and the removal comprises dislodging the lighting units.

4. A process as claimed in any preceding claim wherein the FPD is conveyed to the cutting station so as to arrive in a face down orientation.

5. A process as claimed in claim 1 or claim 2 wherein the cutting station comprises at least one saw tool for cutting the screen and preferably comprises a first saw tool and at least one further saw tool for cutting the screen, and wherein the respective saw tools are adapted to have generally parallel cutting paths separated by a span distance.

6. A process as claimed in claim 4 or 5 wherein the first saw tool is fixed and wherein the further saw tool is adapted to travel with respect to the first cutting tool, so as to permit a variation in the cutting span to a predetermined distance depending upon one or more dimensions of the FPD screen to be cut.

7. A process as claimed in any of the preceding claims wherein the cutting station is provided with means for rotating the FPD about a vertical rotation axis after cutting of the LCD screen along paths in a first direction to allow cutting of the screen along paths in a second direction perpendicular to the first direction so as to produce the said generally rectilinear sub-unit of the LCD display screen.

8. A process as claimed in claim 7 wherein the means for rotating comprises a robot arm.

9. A process as claimed in any of the preceding claims wherein an FPD characterisation station is provided in advance of, or at, the cutting station, the characterisation station being adapted to obtain or retrieve appropriate cutting path information for the FPD for use in the cutting station.

10. A process as claimed in claim 9 wherein cutting path information for a range of known FPDs is stored in a database associated with a data processing system and for each FPD entry in the database one or more characterisation variables associated with the FPD is or are stored in the database, so that the an obtained characterisation variable may be compared with the stored variables so identify a matching stored FPD, or closest match to a stored FPD, or in the absence of these a null a result.

11. A process as claimed in claim 10 or 11 wherein the characterisation station comprises a weigh station adapted to weigh the FPD so as to provide a measured weight value for the FPD, which weight value is sent to the data processing system, the measured FPD weight value being compared with the associated database which comprises known FPD weights so as to obtain one or more candidate FPD matches based upon identical weight, or closest, weight, thereby determining the appropriate cutting path information for use in the subsequent LCD screen cutting.

12. A process as claimed in any of claims 9 to 11 wherein the FPD characterisation station comprises an optical scanner, preferably a 3-D scanner.

13. A process as claimed in claim 12 wherein the optical scanner measures one or more dimensional variable of the FPD.

14. A process as claimed in claim 13 where in the variable comprises one or more of: FPD housing width and or length and/or diagonal extent, LCD screen width and/or length, and/or diagonal extent.

15. A process as claimed in any of claimed 13 or 14 wherein the dimensional variable or variables i s/are compared to corresponding known FPD dimensional variables provided in the database, so as to permit matching based upon identical, or closest, dimension variable(s), with the appropriate cutting paths thereby being retrieved.

16. A process as claimed in any of claims 12 to 15 wherein the optical scanner measured dimension variables concern the disposition of the LCD screen area within the front face of the FPD, so as to determine appropriate cutting paths directly from the FPD itself.

17. A process as claimed in claim 15 which is invoked when a null match, or failure to get a closest match within an acceptable tolerance value, is obtained from the comparison with the database of FPDs, so that the FPD is determined to be unknown.

18. A process as claimed in claim 17 wherein upon determination of an unknown FPD, the data processing system establishes a new database entry which is populated with characterisation variables and/or appropriate cutting paths.

19. A process as claimed in claim 18 wherein one or more of the characterisation variables and/or cutting paths i s/are obtained from the characterisation station.

20. A process as claimed in claim 18 or 19, wherein one or more of the characterisation variables and/or cutting paths is obtained manually by prompting a human operator to perform one or more of the characterisation measurements and/or derive the cutting paths, and enter these into the database.

21. A process as claimed in any of claims 10 to 20 wherein the FPD is provided with an optical identifier on an external surface of the FPD and the characterisation station comprises an optical identifier reader.

22. A process as claimed in claim 21 wherein the optical identifier comprises a product serial number and/or a barcode and/or QR code (2D matrix barcode)

23. A process as claimed in claim 22 wherein the optical identifier reader comprises an optical character recognition (OCR) vision tool for reading the serial number,

24. A process as claimed in claim 22 wherein the optical identifier reader comprises a barcode reader vision tool for reading the barcode.

25. A process as claimed in any of claims 21 to 24 wherein the optical identifier reader obtains the identifier from the FPD and matches the FPD with one of a pre-populated database of said identifiers, the database including FPD dimension and/or cutting path information to be used in the cutting station.

26. A process as claimed in claim 25 wherein the identifier is a product make and/or model number.

27. A process as claimed in any of claims 9 to 26 wherein the identity of each FPD processed is logged by the data processing system, so as to provide an audit of FPD makes and models processed over time.

28. A process as claimed in any of the preceding claims wherein the dislodgement and or detachment of backlight (CCFL tubes/LEDs) is conducted by a router tool at the tube treatment station.

29. A process as claimed in any of the preceding claims wherein a first robot arm holds the FPD chassis at an orientation and location suitable for routing to take place.

30. A process as claimed in claim 29 wherein the location is generally over a hopper or chute positioned that the backlight treatment station so that tubes and tube debris falls into the hopper or chute from the FPD chassis.

31. A process as claimed in any of the preceding claims wherein collected tubes or tube material is conveyed into a shredder or crusher-compactor.

32. A process as claimed in any of the preceding claims wherein crushed tube material is used to fill storage containers which are hermetically sealed for disposal or further processing.

33. A process as claimed in any of claims 28 to 32 wherein the routing is carried out by a further robot arm equipped with the router tool.

34. A process as claimed in claim 33 wherein the routing takes place by scanning the router incrementally back and forth across the aperture defined by removal of the LCD screen sub-unit.

35. A process as claimed in any of claims 29 to 34 wherein the first robot arm holds the FPD chassis face-down over the hopper or chute, preferably in an inclined orientation of 10 to 80 degrees from the vertical, so that any removed tube material falls directly into the hopper or chute.

36. A process as claimed in claim 35 wherein the robot arm thereafter places the FPD chassis onto an exit conveyor for subsequent storage, recycling or disposal.

37. A process as claimed in any of the preceding claims which is carried out using apparatus located in a controlled environment which removes air entrained hazardous particles or gases.

38. A process as claimed in any of the preceding claims wherein the process apparatus incudes an air extraction system in which extraction vents are provided in the region of the screen cutting station and/or the routing station so that air-entrained debris ejected by or from the cutting and or routing stations is extracted from the cutting or routing locations and accumulated for disposal or recycling.

39. A process as claimed in any of the preceding claims wherein the FPD is delivered to the cutting station in a face-down orientation, with the cutting blades extending upwards to effect cutting of the LCD screen.

40. A process for the disassembly of backlit LCD flat panel display units (FPDs) which each comprise an LCD screen which occupies a front face of the FPD and a housing which accommodates the LCD screen, with backlights for illuminating a back side of the LCD screen, the backlights comprising at least one CCFL tube disposed at one end region of the housing and at least one further CCFL tube disposed at an opposite end region of the housing, with a light guide plate disposed between the CCFL tubes to provide the back side illumination, the housing including a front border region which serves as a frame around the visible LCD screen, wherein the method comprises: conveying one of said LCD FPDs to a cutting station and cutting into the exposed LCD display screen along two substantially parallel cutting paths which are offset inwardly from the opposite end regions of the housing which contain the CCFL tubes, the cuts being sufficiently deep to completely remove the said end regions of the housing with the CCFL tubes contained therein, so as to produce two end region units and a screen sub-unit comprising the majority of the LCD screen, collecting the two end regions for subsequent treatment of the CCFL units and conveying the LCD screen sub-unit for storage, disposal or further processing.