METHOD FOR DETECTING THE PRESENCE OR ABSENCE OF AN OPHTHALMIC LENS WITHIN A RECEPTACLE

Abstract

The present invention relates to a method and a lens detection station for detecting the presence or absence of an ophthalmic lens capable of absorbing UV-light, in particular a contact lens, in a receptacle. The method comprises the steps of: irradiating at least a portion of said receptacle where said ophthalmic lens is supposedly accommodated with UV-light, said receptacle having an absorbance for said UV-light which is significantly different from that of the ophthalmic lens, detecting UV-light coming from said irradiated portion of said receptacle where said ophthalmic lens is supposedly accommodated, analyzing said detected UV-light, and from said analysis of said detected UV-light determining the presence or absence of a said ophthalmic lens.

Claims

1.-11. (canceled)

12. A method for detecting the presence or absence of an ophthalmic lens capable of absorbing UV-light, in a receptacle, the method comprising the steps of: irradiating at least a portion of said receptacle where said ophthalmic lens is supposedly accommodated with UV-light, said receptacle having an absorbance for said UV-light which is significantly different from that of the ophthalmic lens, detecting UV-light coming from said irradiated portion of said receptacle where said ophthalmic lens is supposedly accommodated, analyzing said detected UV-light, and from said analysis of said detected UV-light determining the presence or absence of a said ophthalmic lens in said receptacle.

13. The method according to claim 12, wherein said step of irradiating comprises irradiating said portion of said receptacle with radiation comprising UV-light of a wavelength in the range of 280 nm to 380 nm.

14. The method according to claim 12, wherein said step of irradiating is performed using a UV-laser.

15. The method according to claim 13, wherein said step of detecting UV-light is performed using a detector capable of detecting said UV-light of a wavelength in the range of 280 nm to 380 nm, wherein further said step of analyzing said detected UV-light comprises comparing the intensity of said detected UV-light of a wavelength in the range of 280 nm to 380 nm detected by said detector with a predefined threshold, and wherein in case the intensity of said detected UV-light of a wavelength in the range of 280 nm to 380 nm detected by said detector is less than said predefined threshold the presence of said ophthalmic lens is determined.

16. The method according to claim 14, wherein said step of detecting UV-light is performed using a detector capable of detecting said UV-light of a wavelength in the range of 280 nm to 380 nm, wherein further said step of analyzing said detected UV-light comprises comparing the intensity of said detected UV-light of a wavelength in the range of 280 nm to 380 nm detected by said detector with a predefined threshold, and wherein in case the intensity of said detected UV-light of a wavelength in the range of 280 nm to 380 nm detected by said detector is less than said predefined threshold the presence of said ophthalmic lens is determined.

17. The method according to claim 12, wherein said step of irradiating said portion of said receptacle with the said UV-light and said step of detecting said UV-light coming from the said irradiated portion of said receptacle are performed with said receptacle being filled with a liquid.

18. The method according to claim 13, wherein said step of irradiating said portion of said receptacle with the said UV-light and said step of detecting said UV-light coming from the said irradiated portion of said receptacle are performed with said receptacle being filled with a liquid.

19. The method according to claim 15, wherein said step of irradiating said portion of said receptacle with the said UV-light and said step of detecting said UV-light coming from the said irradiated portion of said receptacle are performed with said receptacle being filled with a liquid.

20. The method according to claim 12, wherein said portion of said receptacle is irradiated with said UV-light from beneath a bottom of said receptacle or from above a top surface of said receptacle, and wherein said UV-light coming from said portion of said receptacle is detected on a side of said receptacle opposite to that side from which said portion of said receptacle is irradiated.

21. The method according to claim 15, wherein said portion of said receptacle is irradiated with said UV-light from beneath a bottom of said receptacle or from above a top surface of said receptacle, and wherein said UV-light coming from said portion of said receptacle is detected on a side of said receptacle opposite to that side from which said portion of said receptacle is irradiated.

22. The method according to claim 12, wherein a removable cover which is non-transparent to said UV-light is attached to a top surface of said receptacle, and wherein both said step of irradiating said portion of said receptacle with said UV-light as well as said step of detecting said UV-light coming from said irradiated portion of said receptacle are performed from beneath a bottom of said receptacle.

23. The method according to claim 13, wherein a removable cover which is non-transparent to said UV-light is attached to a top surface of said receptacle, and wherein both said step of irradiating said portion of said receptacle with said UV-light as well as said step of detecting said UV-light coming from said irradiated portion of said receptacle are performed from beneath a bottom of said receptacle.

24. The method according to claim 14, wherein a removable cover which is non-transparent to said UV-light is attached to a top surface of said receptacle, and wherein both said step of irradiating said portion of said receptacle with said UV-light as well as said step of detecting said UV-light coming from said irradiated portion of said receptacle are performed from beneath a bottom of said receptacle.

25. The method according to claim 15, wherein a removable cover which is non-transparent to said UV-light is attached to a top surface of said receptacle, and wherein both said step of irradiating said portion of said receptacle with said UV-light as well as said step of detecting said UV-light coming from said irradiated portion of said receptacle are performed from beneath a bottom of said receptacle.

26. The method according to claim 17, wherein a removable cover which is non-transparent to said UV-light is attached to a top surface of said receptacle, and wherein both said step of irradiating said portion of said receptacle with said UV-light as well as said step of detecting said UV-light coming from said irradiated portion of said receptacle are performed from beneath a bottom of said receptacle.

27. The method to claim 12, wherein said receptacle is made of polypropylene.

28. A lens detection station for detecting the presence or absence of an ophthalmic lens capable of absorbing UV-light, in a receptacle, the lens detection station comprising a UV-light source which is arranged to in operation irradiate with UV-light at least a portion of said receptacle where said ophthalmic lens is supposedly accommodated, the lens detection station further comprising a detector capable of and arranged to in operation detect UV-light coming from said portion of said receptacle where said ophthalmic lens is supposedly accommodated, said detector further being adapted to analyze said detected UV-light and to determine from said analysis the presence or absence of a said ophthalmic lens in said receptacle.

29. The lens detection station according to claim 28, wherein said UV-radiation source is adapted to in operation irradiate said portion of said receptacle with UV-light of a wavelength in the range of 280 nm to 380 nm, and wherein said detector is capable of detecting UV-light of a wavelength in said range of 280 nm to 380 nm.

30. The lens detection station according to claim 28, wherein said UV-radiation source is a UV-laser.

31. The lens detection station according to claim 29, wherein said UV-radiation source is a UV-laser.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further advantageous aspects of the invention become apparent from the following description of embodiments of the invention with the aid of the drawings in which:

[0036] FIG. 1 shows a method and lens detection station according to a first embodiment of the invention with no contact lens being present in the receptacle;

[0037] FIG. 2 shows the method and lens detection station according to FIG. 1 with a contact lens being present in the receptacle;

[0038] FIG. 3 shows a method and lens detection station according to a second embodiment of the invention with no contact lens being present in the receptacle;

[0039] FIG. 4 shows the method and lens detection station of FIG. 3 with a contact lens being present in the receptacle;

[0040] FIG. 5 shows a diagram representing the transmittance of polypropylene as a function of the wavelength;

[0041] FIG. 6 shows a diagram representing the absorbance of water as a function of the wavelength; and

[0042] FIG. 7 shows a diagram representing the transmittance of a contact lens as a function of the wavelength.

DETAILED DESCRIPTION OF EMBODIMENTS

[0043] FIG. 1 and FIG. 2 illustrate a method and lens detection station 1 according to a first embodiment of the invention, the lens detection station 1 comprising a receptacle 10 for accommodating a contact lens 3, a UV-light source 11 and a detector 12 capable of detecting UV-light. A UV-diode laser may be used as UV-light source 11, for example the diode laser Stradus 375-60 available from the company Vortran Laser Technology, Inc., Sacramento, Calif., U.S.A., providing UV-light at a wavelength of 375 nm, or can be a simple UV-laser diode. The receptacle 10 may be made of polypropylene and is more or less transparent to light over a broad wavelength range, including UV-light. FIG. 5 shows a diagram representing the transmittance T.sub.R of the polypropylene receptacle to light in percentages as a function of the wavelength at an intensity of 1 W/cm.sup.2, for example. As can be seen in FIG. 5, at a wavelength of 375 nm (UV-A range) the transmission T.sub.R is about 84% (dashed vertical line indicating 375 nm and dashed horizontal line indicating about 84% T.sub.R).

[0044] Although not mandatory, the receptacle 10 may be filled with a liquid, for example saline (which is mainly water containing a small amount of sodium chloride and some small amounts of preservatives). The absorbance of saline practically corresponds to the absorbance of water, at least for the purpose of the present invention. The absorbance Aw of water in percentages as a function of the wavelength is shown in the diagram of FIG. 6, and is representative for the absorbance of saline, at least for the purpose of the present invention. As can be seen in FIG. 6, and illustrated by the dashed lines, at the afore-mentioned wavelength of 375 nm (which is in the UV-A range) the absorbance A.sub.W is about 2.5% corresponding to a transmission of about 97.5%.

[0045] The diagram shown FIG. 7 represents the transmittance T.sub.CL of the contact lens 3 as a function of the wavelength. As can be seen in FIG. 7 at the afore-mentioned wavelength of 375 nm (which is in the UV-A range) the transmission T.sub.CL is about 13%. As can be seen further in FIG. 7, in the UV-B range (280 nm-315 nm) the transmission is practically zero, the UV-light of that wavelength range is practically completely absorbed by the contact lens 3.

[0046] The UV-light source 11 is arranged to in operation irradiate with UV-light 14 at least a portion of the receptacle 10 where the contact lens 3 is supposedly accommodated.

[0047] As shown in FIG. 1 and FIG. 2, the UV-light source 11 is arranged beneath a bottom of the receptacle 10 to irradiate the receptacle 10 from beneath. The detector 12 is arranged above a top surface of the receptacle 10 to detect UV-light 15 of the said wavelength of 375 nm coming from the irradiated portion of said receptacle 10 where the contact lens 3 is supposedly accommodated.

[0048] In case no contact lens 3 is present in the receptacle as is shown in FIG. 1, the detector 12 detects the intensity of the detected UV-light 15 that has passed through the irradiated portion of the receptacle 10, however, as there is no contact lens 3 contained in the receptacle 10, the intensity of the detected UV-light 15 is not reduced by such contact lens 3. In case a contact lens 3 is present in the receptacle, the intensity of the detected UV-light 15 is reduced as absorption by the contact lens 3 has occurred, or no detected UV-light 15 is detected by the detector 12 (in the case that all UV-light has been absorbed by the contact lens), as this is indicated in FIG. 2.

[0049] This difference in the intensity of the detected UV-light 15 can be readily determined by an evaluation component 16 of the detector 12. The evaluation component 16 analyzes the intensity of the detected UV-light 15 and, from the intensity of the detected UV-light 15, determines whether or not a contact lens 3 is present in the receptacle 10. This determination can be performed, for example, by comparing the intensity of the detected UV-light 15 with a predefined threshold. The predefined threshold can be chosen such that the detected intensity of the UV-light 15 is sufficiently above the predefined threshold in case no contact lens 3 is present in the receptacle 10, and is sufficiently below the predefined threshold in case a contact lens 3 is present in the receptacle 10. The threshold can be predefined, for example, on the basis of one or more calibration measurements in which no contact lens 3 is present in the receptacle 10, and on the basis one or more calibration measurements in which a contact lens 3 is present in the receptacle 10. The predefined threshold is then set between these intensities (obtained from the calibration measurements with and without contact lens), so that once the predefined threshold has been set only a comparison of the actual intensity of the detected UV-light 15 with the predefined threshold must be performed to determine whether or not a contact lens 3 is present in the receptacle 10.

[0050] Alternatively, the intensity of the UV-light 14 of the UV-light source 11 irradiating the portion of the receptacle 10 can be adjusted such that in case a contact lens 3 is present in the receptacle 10 no detected UV-light 15 is detected by the detector 12, whereas in case no contact lens 3 is present in the receptacle 10, detected UV-light 15 can be detected by the detector 12.

[0051] FIG. 3 and FIG. 4 illustrate a second embodiment of the method and a lens detection station 2 according to the invention. Some of the above discussed aspects related to the first embodiment also apply to the second embodiment. Thus, they are not discussed again. Concerning these aspects, reference is made to the description of the first embodiment.

[0052] In the second embodiment, the lens detection station 2 comprises a receptacle 20 for accommodating a contact lens 3, a UV-light source 21 and a detector 22. A removable cover 23 (for example an aluminum foil) which is non-transparent to UV-light is attached (e.g. laminated) onto a top surface of the receptacle 20 (see FIG. 3 and FIG. 4).

[0053] The UV-light source 21 and the detector 22 are both arranged beneath a bottom surface of the receptacle 20 in a manner such that the UV-light source 21 in operation irradiates with UV-light 24 a portion of the receptacle 20 where the contact lens 3 is supposedly accommodated. The detector 22 is arranged to detect UV-light 25 coming from the irradiated portion of the receptacle 20. The receptacle 20 is filled with liquid (e.g. saline).

[0054] The principle of operation is somewhat similar to that of the first embodiment, except that in the second embodiment detection is not performed in transmission. Instead, UV-light 25 coming back from the receptacle 20 is detected by the detector 22. In case no contact lens 3 is present in the receptacle 20, the UV-light 24 of the UV-light source 21 irradiating the portion of the receptacle 20 passes through the receptacle 20, is reflected or diffracted at the cover 23, and passes through the receptacle 20 again before the UV-light 25 coming from the receptacle 20 is detected by the detector 22. In case a contact lens 3 is present in the receptacle 20, the UV-light 24 of the UV-light source 20 passes through the contact lens 3, is reflected or diffracted at the cover 23 and passes again through the contact lens 3, so that either UV-light 25 of reduced intensity is detected by the detector 22, or no UV-light 25 is detected by the detector 22 (in the case that the UV-light has been completely absorbed by the contact lens 3), see FIG. 6. The evaluation component 26 of the detector 22 again determines the presence or absence of a contact lens 3 through comparison with a suitable predefined threshold, as has been described for the first embodiment.

[0055] Embodiments of the invention have been described above with the aid of the drawings, however, it is obvious that many changes and/or modifications are possible without departing from the teaching underlying the invention. Therefore, such changes or modifications are intended to be within the scope of protection which is defined by the appended claims.