SYSTEM AND METHOD FOR IDENTIFYING AN ARTICLE TO WHICH A LABEL IS ATTACHED

Abstract: A system and method for identifying an article to which a label is attached, the label comprising a radiation responsive or absorbing device which is exposed to radiation of a predetermined frequency or group of frequencies. The response to or absorption of the radiation is detected to identify the label and hence the article to which it is attached.

Description: The present invention relates to a system and method for identifying a textile or other type of article to which a lable is attached. The identification of a textile article from 5 amongst large numbers of similar or identical articles, as is often required in for example laundries, is most frequently achieved using a lable which is secured to the article and which comprises information concerning, the identity of the article. Unfortunately 10 in order to ascertain the information carried by the lable it is necessary for " an operator first to find the lable and then visually or physically to examine it. This is a laborious, time-consuming and con¬ sequently expensive procedure especially where large 15 numbers of substantially identical articles are in olved. It is an object of the present invention to obviate or mitigate the above problem. According to the present invention, there is 20 provided a system for identifying ah article to which a lable ' is attached, characterised in that the label comprises means adapted to absorb or respond to radiation of a predetermined frequency or range of frequencies, means for exposing the label to radiation 25 at said predetermined frequency or range of frequencies, and means for detecting the absorption of or response to the radiation by the label. Preferably the label comprises a device which is normally in a quiescent state but which-when exposed SUBSTITUTE SHEET " to said radiation of a predetermined frequency or range of frequencies-assumes an excited state, and the detecting means comprise means for detecting the excitation of the device. The invention also provides a method for identifying an article to which a label is attached; characterised in that the label comprises means adapted to absorb or respond to radiation of a predetermined frequency or range of frequencies, the label is exposed to radiation at said predetermined frequency or range of frequencies, and the absorption of or response to the radiation by the label is detected. Preferably the label comprises a device which is normally in a quiescent state but which when exposed to said radiation of a predetermined- frequency or range of frequencies assumes an excited state, and the excitation of the device is detected. The device may be magnetically coupled to the means for exposing the label to radiation. In one form of the invention the device is in the form of a tuned circuit which may be caused to resonate by placing the circuit near to a coil energised with an AC signal. Oscillation of the tuned circuit changes the current through the coil and this current change can be detected. As an alternative, the device may be fabricated from a material which may be excited by radiation at one frequency to emit radiation at a second.frequency. SUBSTITUTE c- ~~ " " - As a further alternative, the device may be fabricated from a material which selectively absorbs radiation at said predetermined frequency or frequencies. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which : Fig. 1 shows a label embodying the present invention incorporating a tuned circuit; and Fig. 2 illustrates the construction of a label embodying the present invention. With reference to Fig. 1 there is shown a label 1 incorporating a tuned circuit comprising an inductor 2, a capacitor 3 and a resistor 4. The resonant frequency of the tuned circuit is determined by the component values of the inductor 2 and the'capacitor 3. As a result the label 1 may be identified according to the resonant frequency of the tuned circuit incorporated therein. In use the resonant frequency of the tuned circuit is determined by bringing the label into close proximity to a coil 5 which is excited by a variable frequency AC generator (not shown) . The magnetic _ flux generated by the coil 5 magnetically couples the coil 5 to the inductor 2, the coil 5 and inductor 2 effectively forming the primary and secondary windings of a transformer. As a result an alternating voltage is induced into the inductor 2. When the frequency • of the alternating voltage induced into the inductor 2 corresponds to the resonant frequency of the tuned circuit resonance occurs, which results in the current SUBSTITUTE SHEET . - - _ in the coil 5 increasing significantly, the actual value attained being dependent on the value of resist 4. This increase in current may be detected using known apparatus 6, for example a current meter. 5 As an alternative to detecting the increase in curren in the coil 5 the step change in the phase angle between the voltage and current in the coil 5 which occurs at resonance may be used. Again, known appara may be used to detect the change in phase. 10 In order that the label may be flexible, and wash and dry clean resistant in use, the circuit is preferably incorporated in or laminated, printed or etched on a flexible substrate which is then sealed or encapsulated within the label as shown in Fig. 2. 15 Alternatively the label may be rigid or semi-rigid, particularly if its physical dimensions are small. Fig. 2 shows a schematic view of a label 7 applied to an article 8. A substrate 9 comprising the circuit elements is sealed using a lacquer within -20 .the label 7. Alternatively the label 7 may be coated using an injection moulding process or dip •" coated or powder coated and sintered. '•' - A capacitor may be- produced by printing, etchin or laminating adjacent layers of conducting and 25 dielectric materials onto the substrate 8. A coil and a resistor may be produced simply by printing, etching or laminating coaductors onto the substrate 8. The label employed in the present ' invention may OMPI SUBSTITUTE SHEET " ϊ p δ " usefully comprise a heat transfer or heat sealable element made from a resin system capable of being transferred to a substrate by the application of heat . and pressure. Such a heat transfer may be made in accordance with one of our previous patents, e.g. British Patents 928 347, 1 201 713, 1 215007, 1 287452, 1 386 392 and 1 523869 and German Published Specification 28 22 411. Alternatively, the label may be inserted into a pouch formed in the article to be labelled. The label could thus be concealed if desired. It will be appreciated that the circuit incorporated into the label need not be as simple as a tuned circuit. By the addition of further circuit elements band pass, or band stop filters may be incorporated into the label. Active elements such as transistors, diodes and integrated circuits may also be produced on the substrate. As a result a label which incorporates a small receiver/trans itter may be provided. Power may be derived from the voltage induced in a coil on the substrate and a frequency characteristic of the label is transmitted. This arrangement eliminates the need to provide a variable frequency AC generator as a number of receivers each tuned to a characteristic frequency •may be used. As a further embodiment of the present invention materials such as pigments may be incorporated into the label which respond by emitting radiation at a SUBSTITUTE characteristic frequency or which selectively absorb radiation at a characteristic frequency when irradiate with for example ultra-violet, infra red or X-ray radiation. OMPI WIPO SUBSTITUTE SrϊE__T &as ΔT ia*

Claims: CLAIMS : - . A system for identifying an article to which a label is attached, characterised, in that the label comprises means adapted to absorb or respond to radiation of a- predetermined frequency or range of frequencies, means for exposing the label to radiation at said predetermined frequency or range of frequencies, and means for detecting the absorption of or response to the radiation by the label. 2. A system according to claim 1, characterised in that the label comprises a device which is normally in a quiescent state but which when exposed to said radiation of a predetermined frequency or range of frequencies assumes an excited state, and the detecting means comprise, means for detecting the excitation of the device. 3. A system according to claim 2, characterised in that the device is magnetically coupled to the means for exposing the label τo radiation. 4. A system according to claim 3, characterised in that the device comprises a tuned circuit, and the means for exposing the label to radiation comprises a coil energised with an AC signal, the tuned cir?uit being adapted to resonate when placed near to the coil.- 5. A system according to claim 4, wherein the detecting means comprise means for detecting -variations in the current through the coil. 6. A system according to claim 2, characterised in that when the device is in said excited state it OMPI WIPO #_-_-» ■ r~ ■—"-T-'r. '-r", ITT"* <C" » - -— '- ■ ^ Zn emits radiation at a frequency different from the said predetermined frequency or range of frequencies, and the detecting means comprises means for detecting the radiation emitted by the device. 5 7. A system according to claim 6, characterised in that the device comprises a material which responds by emitting radiation at said different frequency when irradiated with radiation at said predetermined frequency or frequencies. 10 8. A system according to claim 1, characterised in that the device comprises a material which selectively absorbs radiation at said predetermined frequency or frequencies. 9. A method for identifying an article to 15 which a label is attached, characterised in that the label comprises means adapted to absorb or respond to radiation of a predetermined frequency or range cf frequencies, the label is exposed to radiation at said predetermined frequency or range of frequencies, 20 and the absorption of or response to the radiation by the label is detected. 10. A method according to claim 9 , characterised in that the label comprises a device which is normally in a quiescent state but which when exposed to said 25 radiation of said predetermined frequency or range of frequencies assumes an excited state, and the excitati of the device is detectec. SUBSTITUTE SHϊ

Inventors: DUDLEY P, HUTCHINSON M
Applicants: DUDLEY P, HUTCHINSON M, POLYMARK INT LTD
Application year: 1981
Main classification: G06K19
IPC codes: G06K19, H04B5