Patent Description:
Transparent cylinders are widespread in various fields such as laboratory glassware in the form of beaker or metering cylinder, food container in the form of tub or bottle or medical glassware in the form of vial, cartridge or syringe. Whatever the field considered, these different containers require a high degree of quality and cleanliness, especially in the medical field where quality and/or cleanliness issues may have a direct impact on the safety of patients and medical staff.

Indeed, transparent cylinders, made of glass or plastic, are produced by complex manufacturing processes that may result in the formation of particles or defects in the material itself or on its surface. A careful inspection step of such transparent cylinders is thus required before delivery to the customer.

Such an inspection step is usually made automatically by cameras using a back end light positioned behind the transparent cylinder. However, this kind of inspection does not allow the detection of small-size cosmetic defects and/or glass particles. Furthermore, such an inspection system is not specific as it cannot differentiate the different types of observed defects.

The document <CIT> discloses a method of detecting defects in a bottle body, wherein light is projected by a light source from outside the field of view to the body of the bottle, and the transmitted refraction / scattered light is received by an imaging device through the light-transmitting part of the light-blocking member. A shielding plate having a diameter smaller than the body of the bottle is placed between the light source and the body of the bottle.

There is therefore a need for a reliable system able to detect small glass particles and cosmetic defects.

A goal of the present invention is to propose an improved inspection system able to detect small-sized glass particles and defects. Another goal of the present invention is to provide an inspection system able to discriminate the different types of defects.

The goals are achieved by the inspection system as defined in claim <NUM>.

According to the claimed invention the system comprises acquisition means substantially aligned with the light source and the mask along the inspection axis for acquiring an image of the transparent cylinder such that, when the transparent cylinder is positioned in the system for inspection, the acquisition means are opposite to the mask relative to the transparent cylinder.

According to an embodiment, the system further comprises a holder capable of supporting the transparent cylinder such that the longitudinal axis is perpendicular to the inspection axis.

The expression "substantially aligned" means that the light source, the mask and the acquisition means are aligned on the inspection axis, although a small deviation is acceptable. The specific set-up of the inspection system according to the present invention can be easily realized by a skilled person in the art by checking the image acquired by the acquisition means.

All kind of transparent cylinders can be inspected with the inspection system of the present invention, such as laboratory glassware, food containers or medical glass wares. Examples of such cylinders are beakers, metering cylinders, bottles, jars, medical vial, cartridges or syringes. Any other cylinders may be inspected as long as they are made of a transparent material. Thanks to the partial illumination of the transparent cylinder, any particle inside the non-illuminated part of the transparent cylinder is illuminated by an indirect light refracted by the illuminated portion of the transparent cylinder and is clearly visible in front of the mask acting as a dark background. Such illuminated particles may be easily detected by the acquisition means such as a human eye or a video camera.

The non-illuminated portion of the transparent cylinder may range from <NUM> to <NUM>% of the diameter of the transparent cylinder, preferably <NUM> to <NUM>% and more preferably <NUM> %.

The mask may be positioned in the inspection system with regard to the transparent cylinder such as to prevent illumination of a central portion, around the longitudinal axis of the transparent cylinder, in such a way that only the radial peripheries of the transparent cylinder are illuminated by the light source. This configuration of the inspection system is especially adapted to detect glass particles at the surface of the transparent cylinder or inside the transparent cylinder itself. In another configuration, the mask may be positioned such as to prevent illumination of a longitudinal periphery of the transparent cylinder, in such a way that a single radial periphery of the transparent cylinder is illuminated by the light source. Preferably, the illumination of the transparent cylinder may be prevented on a half of its diameter, the longitudinal axis being therefore a limit between the illuminated and the non-illuminated portion of the transparent cylinder. This configuration allows detecting both scratches and particles, the scratches being detectable in the illuminated central portion of the transparent cylinder and the particles in the non-illuminated portion of the transparent cylinder.

According to the configuration of the inspection system, both particles and scratches may be detected during a single inspection step. Such an inspection system is thus able to differentiate a particle from a scratch which allows an accurate inspection of transparent cylinders.

In embodiments, the mask is opaque to the light emitted by the light source and preferably black-colored. This allows for an optimized contrast to detect easily particles above <NUM>. The mask may be made from any appropriate material such a wood, cardboard, plastic or metal.

The light source is preferably able to generate a white light. LEDs, halogen bulbs or neon tube may be used.

In embodiments, the inspection system is further provided with rotary means able to rotate the transparent cylinder with regard to the inspection system or to rotate the inspection system with regard to the transparent cylinder. The rotation of the inspection system or the rotation of the inspected cylinder allows in both cases a fast and comprehensive inspection of the transparent cylinder.

The goals are also achieved by the method to inspect a transparent cylinder as defined in claim <NUM>.

In embodiments, the method to inspect a transparent cylinder further comprises a rotation of the transparent cylinder around its longitudinal axis with regard to the mask and the light source.

In embodiments, the method to inspect a transparent cylinder further comprises a rotation of the mask and the light source around the longitudinal axis of the transparent cylinder.

Both rotations allow a fast and comprehensive inspection of the transparent cylinder.

<FIG> shows a syringe <NUM> as an example of a transparent cylinder that can be inspected by a system according to the present invention. Others examples of transparent cylinders include cartridges, vials as well as bottles and glassware such as glasses, beakers or metering cylinders (not shown). The syringe <NUM> of <FIG> includes a cylindrical transparent barrel <NUM> having a diameter D, a longitudinal axis A and defining a tubular chamber <NUM> with two extremities. One of the extremities of the syringe <NUM> corresponds to a tip <NUM> used for the injection of medical products and that may be provided with a staked needle or an adaptor for connecting an intravenous line or any other types of connectors. The other extremity of the cylindrical transparent barrel <NUM> corresponds to a flange <NUM> used for gripping the syringe <NUM>. The syringe <NUM> may be made from any transparent material such as glass or plastic, for example polyethylene, polypropylene, polycarbonate or cyclic polyolefin and any combination thereof.

In <FIG>, a schematic inspection system <NUM> comprises a black mask <NUM>, a light source <NUM> and acquisition means <NUM>. The mask <NUM>, the light source <NUM> and the acquisition means <NUM> are aligned on an axis B, hereinafter called inspection axis. To perform an inspection, the syringe <NUM> is placed between the mask <NUM> and the acquisition means <NUM> so that its longitudinal axis A is perpendicular to the axis B. The acquisition means <NUM> may be any acquisition means capable of obtaining an image of the cylinder, for example the eye of an operator or a video camera.

The operational principle of the inspection system <NUM> according to the present invention is described with reference to <FIG>. As already mentioned, the light source <NUM>, the mask <NUM>, the transparent cylinder under inspection, for example a syringe <NUM>, and the acquisition means <NUM> are aligned on the inspection axis B, the syringe <NUM> being placed between the mask <NUM> and the acquisition means <NUM>. To that end, the syringe may be supported by a holder (not shown) or handheld by an operator. When the light source <NUM> is switched on, a portion of the emitted light EL is blocked by the mask <NUM> and only the peripheral light L passing around the mask <NUM> thus reaches the syringe barrel <NUM>. Because of the cylindrical shape of the syringe barrel <NUM>, the light is refracted to illuminate particles and for instance, a particle P. As shown in <FIG>, which shows the syringe and mask from the point of view of the acquisition means, the illuminated particle P is easily detectable on an image acquired by the acquisition means <NUM>, thanks to the black mask that acts as a black background. A rotation of the syringe <NUM> around its longitudinal axis A or a rotation of the light source, the mask and the acquisition means around the longitudinal axis A of the syringe <NUM> is preferable in order to inspect the whole circumference of the syringe <NUM>.

The width and the positioning of the mask <NUM> with regard to the light source <NUM> and the syringe <NUM> must be chosen in order to block the illumination of <NUM> to <NUM> % of the diameter of the syringe <NUM>. Preferably, <NUM> to <NUM> % of the diameter of the syringe <NUM> are not illuminated, more preferably <NUM> %, as shown in <FIG>. The dimensions and the positioning of the mask <NUM> with regard to the light source <NUM> and the syringe <NUM> may thus be selected for each specific inspection device according to the size of the transparent cylinders to be inspected. In the same way, the arrangement of the mask <NUM>, the transparent cylinder <NUM>, the light source <NUM> and the acquisition means <NUM> into the inspection system <NUM> may be optimized to obtain an acquired image as the one shown in <FIG>.

Moreover, the mask <NUM> is preferentially a plain plate, and as such, configured to block incoming light over the entirety of its exposed surface that receives light from the light source.

In addition, <FIG> show different positioning of the mask <NUM> with respect to the syringe <NUM>, as viewed by the acquisition means <NUM>. In <FIG> and <FIG>, the mask is centered relative to the longitudinal axis A of the syringe <NUM>. This prevents illumination of a central portion of the syringe and this specific configuration is optimal for the detection of glass particles, which are particularly visible in the middle of the transparent barrel <NUM>. In <FIG>, the mask <NUM> is decentered radially relative to the longitudinal axis A of the syringe <NUM> and only covers half of the diameter D, above or below the longitudinal axis A. This position prevents illumination on a half of the diameter D of the longitudinal barrel <NUM> and allows the detection of both scratches and particles as it will be explained below.

In <FIG>, the mask <NUM> has the same length as the barrel <NUM>, which allows inspection of the whole barrel length. However, specific applications may require a mask covering only a partial length of the syringe <NUM>.

Furthermore, the mask <NUM> is preferably positioned parallel to the syringe axis A, although a small deviation may be acceptable.

Finally, the mask <NUM> is preferably opaque to the light emitted by the light source and black-colored in order to provide the greatest possible contrast with particles P. It may be made from any suitable materials such as metal, plastic, paper or cardboard.

Thanks to the mask <NUM>, the syringe <NUM> is illuminated on only a limited portion of its diameter D, the mask <NUM> both blocking part of the light from the light source <NUM> and acting as a dark background for the detection of illuminated particles. The inspection system <NUM> therefore provides a simple and reliable way to detect small size particles, for example particles above <NUM>.

In addition to the detection of particles, the configurations of the inspection system as shown in <FIG> also allow the detection of scratches. Indeed, if the particles remain visible by contrast with the mask <NUM>, the scratches are easily visible under direct illumination, in the portion where the light is not masked by the mask <NUM>. This case is illustrated in <FIG> where the acquisition means <NUM> are able to detect simultaneously both a scratch S in the "white" illuminated region and a particle P in the "black" non-illuminated region.

The light source <NUM> may be any light source producing a homogeneous light. Preferably, the light is a white color light that may be obtained for example with LEDs, halogen bulbs or neon tubes.

In case the acquisition means comprise a video camera, the acquired pictures may be processed with commercially available software designed to identify particles and scratches. Such software may also measure the size of the detected defects and help to reject cylindrical containers having unacceptable defects with respect to the targeted quality level.

In a first embodiment of the present invention visible in <FIG>, a portable inspection system <NUM> comprises a light source <NUM> and an integrated mask <NUM>. The inspection system <NUM> is further provided with a switch button <NUM> and integrated batteries (not shown). For example, this portable inspection system <NUM> may be used manually by an operator for random manual inspections on a manufacturing line. A syringe <NUM> may be positioned by the operator at the right distance from the inspection device <NUM> in order to obtain an image as the ones shown in <FIG> or <FIG>. The syringe <NUM> may also be rotated appropriately by the operator to inspect the whole barrel circumference.

In a second embodiment of the present invention visible in <FIG>, an inspection system <NUM> is set up to inspect syringes <NUM> on an in-line manufacturing process. Syringes <NUM> are carried on a transportation system <NUM> comprising holders such as plugs <NUM> able to maintain the syringes in a vertical positioning. The inspection system <NUM> comprises a rotatable axis <NUM> and a horizontal frame <NUM>. The mask <NUM>, the light source <NUM> and the acquisition means <NUM> are held by the horizontal frame <NUM> and aligned on the inspection axis B. When a syringe <NUM> is presented to the inspection system <NUM>, the light source <NUM> is switched on and the rotatable axis <NUM> is motorized by an electric motor (not shown) in order to rotate the mask <NUM>, the light source <NUM> and the acquisition means <NUM> around the longitudinal axis of the syringe <NUM>. A set of pictures is acquired by the acquisition means <NUM> to inspect the whole circumference of the syringe barrel <NUM> in a very short period of time without removing the inspected syringe from the in-line manufacturing process. The optimal rotating speed depends on the size of the syringe itself, the size of the defects to be detected as well as the quality and the parameters of the acquisition means. For example, <NUM> images with a <NUM> MPx camera may be captured in <NUM> to <NUM> seconds. A casing (not shown) may be provided around the inspection system <NUM>, to prevent or limit light coming from other sources that may reduce the efficiency of the light source <NUM>, the casing thus enhancing the contrast and the detection quality of the inspection device <NUM>.

In a third embodiment disclosed in <FIG>, an inspection system <NUM> is set-up for the automated inspection of a syringe <NUM>. This inspection system <NUM> is provided with a frame <NUM> supporting a mask <NUM>, a light source <NUM> and acquisition means <NUM>. The syringe <NUM> is accommodated on a rotary holder <NUM> comprising two axes (not shown) provided with three wheels (only two are visible in <FIG>, the third wheel being hidden by one the two visible wheels). At least one of the two axes is coupled to an electric motor (not shown) in order to maintain the syringe <NUM> in rotation, the second axis being either motorized or free to rotate. This rotary holder <NUM> allows the full rotation of the syringe <NUM> in order to inspect the whole circumference of the syringe barrel <NUM>. The inspection <NUM> means may be either a video camera similar to the inspection means <NUM> or a magnifying glass for a direct visual inspection. The inspection system <NUM> according to this embodiment is especially adapted for an in-depth inspection of high quality syringes or transparent cylinders before their delivery to customers that will proceed to filling with medical products.

Claim 1:
Inspection system (<NUM>, <NUM>, <NUM>, <NUM>) for detecting a particle and a scratch in a wall of a transparent cylinder (<NUM>) having a longitudinal axis (A) and a diameter (D), the inspection system comprising:
- a light source (<NUM>, <NUM>, <NUM>, <NUM>) able to illuminate a transparent cylinder (<NUM>),
- a mask (<NUM>, <NUM>, <NUM>, <NUM>) able to block at least part of the light coming from the light source,
the light source (<NUM>, <NUM>, <NUM>, <NUM>) and the mask (<NUM>, <NUM>, <NUM>, <NUM>) being arranged such that, when the transparent cylinder (<NUM>) is positioned in the system for inspection, the light source, the mask and the transparent cylinder are substantially aligned along an inspection axis (B) perpendicular to the longitudinal axis (A) of said transparent cylinder and the mask (<NUM>, <NUM>, <NUM>, <NUM>) is interposed between the light source (<NUM>, <NUM>, <NUM>, <NUM>) and the transparent cylinder (<NUM>) so as to prevent direct illumination from the light source of a first portion of the transparent cylinder having a width smaller than the diameter (D) of the transparent cylinder while allowing illumination of a second portion of the transparent cylinder,
- image acquisition means substantially aligned with the light source and the mask along the inspection axis (B), opposite the mask relative to the transparent cylinder, for acquiring an image of an illuminated portion and a non-illuminated portion of the transparent cylinder,
the mask and the image acquisition means being configured so that a scratch present in the wall of the transparent cylinder, located in the second portion of the transparent cylinder, is visible by the acquisition means under direct illumination, and a particle present in the wall of the transparent cylinder, located in the first portion of said transparent cylinder and indirectly illuminated by light refracted by the second portion of the transparent cylinder, is visible by the acquisition means by contrast with the mask, wherein the mask is acting as a dark background.