Testing Equipment and Testing Methods

Abstract

The present invention relates to a test device (1) for detecting defects of a test specimen (5), in particular an ophthalmic lens, using an illumination device (2) for irradiating a transparent test specimen (5) to be inspected and an image acquisition device (3) for imaging the test specimen (5) irradiated by the illumination device (2). The illumination device (2) includes a plurality of linearly adjustable light sources (8) for generating a fringe pattern (7). In order to capture the fringe pattern (7), the acquisition duration of the image acquisition device (3) can be adjusted such that the light emitted by each of these light sources (8) is detected as a light stripe (19.1). Additionally, the present invention relates to a test method for detecting defects of a transparent specimen.

Description

[0001] The present invention relates to a testing device for detecting defects of a test sample, in particular an ophthalmic lens, using an illumination device for transilluminating a transparent test sample to be inspected and an image acquisition device for imaging the test sample transilluminated by the illumination device. The present invention further relates to a testing method for detecting defects of a transparent sample, in particular an ophthalmic lens, comprising:

[0002] (a) an image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the aid of an illumination device;

[0003] (b) a reconstruction step in which the overall image is reconstructed from the fringe records; and

[0004] (c) A defect detection step in which possible defects are detected from the overall image.

[0005] In the production of transparent test specimens, in particular transparent test specimens with an optical effect, such as ophthalmic lenses like spectacle lenses, quality control is usually very time-consuming and is carried out visually without an automated process suitable for the safe and reliable detection of defects. This manual or visual inspection of the test specimens is carried out by trained employees who have to check each test specimen individually for defects during the production process. Typical defects occurring on and / or in the test specimens can be divided into three different categories according to their visual impact. These categories are light absorption defects, light refraction defects and light diffraction defects. In addition, however, defects contained in the test specimens may also belong to several of the aforementioned categories.

[0006] The problem associated with manual or visual testing is that the results of such tests are subjective and can be influenced by various factors. For example, the quality of the quality control and therefore the results depend largely on the tester's daily report, his or her mental state, the time of inspection or other factors. In addition, due to the monotony of the task, the inspection is very tiring for the employees, so that the results are usually not reproducible. In addition, it has proven disadvantageous that the inspection results vary between employees, making it difficult to achieve uniform results. In order to further make the inspection results consistent, extensive training is therefore necessary, which has to be verified within the framework of the measurement system analysis. In addition, it usually takes a very long period of several months to train the inspection personnel, which means that it is impossible to expand the production capacity at short notice.

[0007] In the context of the present invention, a transparent test specimen is understood to mean in particular a test specimen made of a material that can be used for the production of optical components, i.e., in particular a test specimen made of an optical material according to DIN EN ISO 13666:2019-12, section 3.3.1. In particular, in the context of the present invention, a transparent test specimen can be a blank according to DIN EN ISO 13666:2019-12, section 3.8.1, i.e., a piece of optical material with an optically finished surface for the manufacture of ophthalmic lenses, or it can also be a finished ophthalmic lens according to DIN EN ISO 13666:2019-12, section 3.8.7, i.e., an ophthalmic lens with two optically finished surfaces, where edge processing has already been carried out or still needs to be carried out. In addition, the transparent test specimen can also be other blanks or pressings or can also be precision ground parts.

[0008] In the context of the present invention, the terms "linear adjustment" and "linear movement" are used interchangeably.

[0009] Therefore, efforts have been made for some time to automate the inspection of defects in such test specimens in order to ensure reproducible defect detection.

[0010] A comparable test device is also known from US 8,081,840 B2, in which a fringe pattern is displayed by a display that also serves as an illumination device, and the display emits light through a transparent test specimen arranged between the illumination device and the camera and is recorded by the camera. In US 8,081,840 B2, the content depicted on the display is controlled in order to change the position of the fringes between the individual images.

[0011] EP 1 016 860 B1 describes an inspection device in which only the defects on the outer edge of a contact lens are inspected. In EP 1 016 860 B1, for this purpose, the other areas of the contact lens to be inspected are masked such that light from a light source penetrates the contact lens only in the area of the outermost edge region and is guided from there to the camera.

[0012] A test device for inspecting contact lenses is known from EP 1 248 092 A1, in which two images are recorded under different illumination conditions. These images are then evaluated in a downstream step in order to be able to draw conclusions about any defects present in or on the contact lens.

[0013] A test device and a test method of the type mentioned at the beginning are known from WO 2019 / 243568A1, which is considered the closest prior art. Here, a display is used as the lighting device, and geometric patterns with different brightness values, more precisely a stripe pattern with alternating light or white and dark stripes, are displayed on the display, and then these patterns are detected by a camera, wherein a transparent test specimen is arranged between the display serving as the lighting device and the camera. In other words, the display irradiates the test specimen, and the camera captures the corresponding image of the irradiated test specimen. Then, the positions of the light and dark stripes on the monitor change between the individual images. Then, the captured stripe records (or stripe images) can be combined in a recombination step to form an overall image and evaluated for defect detection, for example, as detailed in WO 2019 / 243568 A1. However, WO 2019 / 243568 A1 shows that it is disadvantageous that the individual pixels of the display are also imaged by the camera, which has a negative impact on the automatic detection of defects and thus on the test results.

[0014] Therefore, the object of the present invention is to reduce the above-mentioned disadvantages and to provide an improved test device and an improved test method for defect control.

[0015] This object related to the test device is achieved by the present invention according to any one of claims 1 to 3. The object related to the improved test method for defect control is achieved by the present invention according to one of claims 14 to 16.

[0016] According to a first aspect of a test device for detecting defects in a transparent test specimen, in particular an ophthalmic lens, the test device comprises a lighting device for irradiating the test specimen to be inspected and an image acquisition device for imaging the test specimen irradiated by the lighting device. The lighting device comprises a plurality of light sources which can be linearly moved in a first direction by a first driver to generate a stripe pattern. In order to capture the stripe pattern, the acquisition duration of the image acquisition device can be adjusted such that the light emitted by each light source linearly moved in the first direction by the first driver is detected as a light stripe.

[0017] In other words, the light source moves linearly in a common direction while the image acquisition device captures an image of the test specimen illuminated by the light source. The acquisition duration of the image acquisition device is adapted to the speed of the linear adjustment of the light source such that the light source is not captured or imaged as a separate point by the image acquisition device, but rather as a light stripe, where adjacent light stripes are each separated by a dark stripe. Since each light stripe is ultimately generated by a single light source, it is ensured that when generating the stripe pattern, the stripes all have a uniform shape and, for a test specimen with a fairly flat curvature, at a constant speed, especially within the light stripes - a consistently bright light distribution, which improves the detection of defects in the test specimen. However, depending on the curvature of the test specimen, the light stripes may not exhibit a consistent bright light distribution. The light source is preferably a point light source, such as an LED. In particular, LEDs with a small emission area have proven to be particularly preferred. The test specimen is positioned between the illumination device and the image acquisition device such that the transparent test specimen is transilluminated by the illumination device from one side (e.g., from the rear surface) and captured by the image acquisition device from the other side (e.g., the front surface). In the case of an ophthalmic lens, the front surface of the test specimen complies with DIN EN ISO 13666:2019-12, section 3.2.13, and when used as intended, the surface of the lens should be assembled away from the eye, and the rear surface complies with DIN EN ISO 13666:2019-12, section 3.2.14, and the surface of the lens is assembled closer to the eye side.

[0018] According to a second aspect of a test device for detecting defects in a transparent test specimen, in particular an ophthalmic lens, the test device comprises an illumination device for transilluminating the test specimen to be inspected and an image acquisition device for imaging the test specimen transilluminated by the illumination device. The illumination device comprises a plurality of light sources which are arranged on a light carrier which is linearly movable in a first direction to generate a stripe pattern. In order to capture the stripe pattern, the acquisition duration of the image acquisition device can be adjusted such that the light emitted by each light source arranged on the light carrier and linearly movable in the first direction is detected as a light stripe.

[0019] In a third aspect of the invention, a test device for detecting defects in a transparent test specimen, in particular an ophthalmic lens, comprises an illumination device for transilluminating the test specimen to be inspected and an image acquisition device for imaging the test specimen transilluminated by the illumination device. The illumination device comprises a plurality of point light sources which are designed as LEDs and are linearly movable in a first direction for generating a stripe pattern. In order to capture the stripe pattern, the acquisition duration of the image acquisition device can be adjusted such that the light emitted by each light source linearly movable in the first direction is detected as a light stripe.

[0020] In the present text, it is also demonstrated that it is particularly advantageous to provide a first driver for linear adjustment (i.e., movement of the light source in a first direction) and / or to provide a second driver for linear adjustment of the light source in a second direction that is substantially perpendicular to the first direction, where the first and second directions are in each case substantially perpendicular to the observation path of the image acquisition device. The first driver for linearly adjusting (i.e., moving) the light source in the first direction is used to generate a fringe pattern. According to the invention, the second driver for adjusting the light source in a second direction perpendicular to the first direction is used to reposition the light source between individual fringe recordings. In the context of the present invention, a fringe recording refers to an image of the illuminated test specimen captured by the image acquisition device (which can be a camera) when the light source is linearly adjusted in the first direction. The first driver also ensures that the light source of the lighting device can be adjusted linearly as uniformly as possible, thereby ensuring the uniform generation of light-colored fringes. However, in the context of the present invention, it is also contemplated here that the variation in the position of the light-colored fringes in the second direction between two fringe recordings is affected by the fact that the distance between adjacent light sources is ultimately very small. During the capture of each individual fringe recording, only a part of the light sources are activated, while the remaining light sources remain deactivated. The linear adjustment of the light source in the second direction between fringe recordings can alternatively be performed by the second driver as described above, and then in each case the linear movement is solved by deactivating the previously activated (i.e., illuminating) light source during the next fringe recording and activating one of the adjacent light sources. In other words, only every x-th light source is operated when forming the first fringe recording, and when forming the second fringe recording, the (x + 1)-th light source is operated. The advantage of this is that a second driver is not required.

[0021] To ensure that the light source can be adjusted uniformly in the first and / or second direction, it is also demonstrated that it is advantageous to arrange the light source on a light carrier. In this case, it is also particularly advantageous to demonstrate that the light carrier extends along the second direction. In addition, the light source can be positioned on the light carrier in a particularly simple but at the same time precise manner. In a preferred embodiment, the light carrier is formed as a cuboid whose longitudinal axis extends parallel to the second direction. Moreover, the light carrier can be designed as a one-dimensional grid, i.e., a thin and narrow structure or a cuboid.

[0022] In addition, it has also been shown to be useful to arrange the light sources equidistantly from each other. Thus, the captured fringe recordings are as uniform as possible, which simplifies the downstream evaluation of defect detection. Additionally, the equal distance between the light sources also makes the distances of the light-colored fringes originating from the light sources equal. Therefore, knowing the distance between the light-colored fringes allows the position of the light source to be linearly adjusted appropriately in the second direction between the individual fringe recordings in order to ensure that the entire test specimen is covered with different light-colored fringes.

[0023] It has also proven advantageous that the distance D between adjacent light sources is greater than 3 mm, preferably greater than 5 mm and further preferably less than 12 mm, preferably less than 10 mm, particularly preferably 7 mm. If the distance between adjacent light sources is too small or too large, this has a negative impact on the test device according to the invention and on the detection of defects in the test specimen. For example, if the distance is too large, the number of fringe recordings required increases. On the other hand, if the distance between adjacent light sources is too small, the dark fringe between two light fringes is over-illuminated and it is no longer possible to separate the adjacent light fringes. Moreover, light from two different spatial directions may be superimposed, such that the defects may no longer be visible. In addition, the number of light sources has to be increased in an unfavorable manner.

[0024] It has also been shown that it is advantageous if the number of light sources is greater than 1, preferably greater than 8, particularly preferably greater than 12 and further preferably less than 50, preferably less than 30, most preferably 23. In the case where the test specimen exhibits a strong optical effect, it has proven disadvantageous to use too few light sources, since the outer edge region of the test specimen cannot be illuminated due to the insufficient number of LEDs. Additionally, more fringe recordings have to be captured, which has an adverse effect on the duration of defect detection. On the other hand, if the number of light sources is too large, the technical complexity increases.

[0025] In order to keep the acquisition cycle of the image acquisition device as short as possible, it has been shown that the speed of the first drive for moving the light source in the first direction and / or the speed of the second drive for moving the light source in the second direction is greater than 1,000 mm / s, preferably greater than 2,000 mm / s, particularly preferably greater than 2,500 mm / s and further preferably less than 5,000 mm / s, preferably less than 4,000 mm / s, particularly preferably less than 3,500 mm / s, most preferably 3,000 mm / s. However, with increasing speed, the complexity of the device also increases, and thus a speed of 3,000 mm / s has proven to be a very good compromise. It must also be noted here that it has been shown that a lower speed of the second drive than that of the first drive for linearly adjusting the light source in the first direction is sufficient for adjusting the light source in the second direction. In particular, the linear displacement of the light source in the second direction is significantly lower than that in the first direction, such that a lower speed of the linear displacement of the light source in the second direction between fringe recordings does not necessarily require a significantly longer duration of defect detection.

[0026] The same applies to acceleration: on the one hand, the aim is the highest possible acceleration value in order to achieve the desired speed of the linear movement of the light source as quickly as possible. On the other hand, the higher the acceleration, the higher the technical effort required to achieve these high accelerations. Thus, it has been shown that the acceleration of the first drive and / or the acceleration of the second drive is greater than 10,000 mm / s 2 , preferably greater than 15,000 mm / s 2 , particularly preferably greater than 18,000 mm / s 2 and further preferably less than 30,000 mm / s 2 , preferably less than 25,000 mm / s 2 , particularly preferably less than 22,000 mm / s 2 , most preferably 20,000 mm / s 2 is useful. In particular, an acceleration of 20,000 mm / s 2 proves to be a good compromise. At these high acceleration values, it is particularly ensured that the capture of the fringe recording is not adversely affected by areas where the speed of the light source in the first direction is too low, resulting in a local increase in brightness.

[0027] It has also been shown that it is advantageous for the image acquisition device to include a camera with a telecentric lens. The use of such a telecentric lens provides a limited acceptance angle in order to facilitate the visualization of brightness differences caused by defects, in particular by weakly refractive defects. In addition, even if the test specimen is out of focus, this ensures that the image capture remains accurate. Furthermore, the depth of field is increased and even smaller distortions are achieved. In this context, it has also been shown that it is advantageous to arrange a collimating lens between the illumination device and the test specimen, thereby guiding the light incident on the test specimen in a preferred manner.

[0028] According to a first aspect of the test method, the method comprises: (a) an image acquisition step in which a plurality of fringe recordings are captured by an image acquisition device and generated with the help of an illumination device; (b) a reconstruction step in which the overall image is reconstructed from these fringe recordings; and (c) a defect detection step in which possible defects are detected from the overall image. The illumination device for generating the fringe pattern includes a plurality of light sources that are linearly moved in a first direction by a first drive during the image acquisition step. In order to capture the fringe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by the linearly moved light source is detected as a light fringe respectively.

[0029] According to a second aspect of the testing method, the method comprises: (a) an image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the help of an illumination device; (b) a reconstruction step, in which an overall image is reconstructed from these fringe records; and (c) a defect detection step, in which possible defects are detected from the overall image. The illumination device for generating the fringe pattern comprises a plurality of light sources arranged on an optical carrier, which linearly moves in a first direction during the image acquisition step. In order to capture the fringe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by the linearly moved light sources is respectively detected as light fringes.

[0030] According to a third aspect of the testing method, the method comprises: (a) an image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the help of an illumination device; (b) a reconstruction step, in which an overall image is reconstructed from these fringe records; and (c) a defect detection step, in which possible defects are detected from the overall image. The illumination device for generating the fringe pattern comprises a plurality of point light sources, which are designed as LEDs and linearly move in a first direction during the image acquisition step. In order to capture the fringe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by the linearly moved light sources is respectively detected as light fringes.

[0031] Although the reconstruction step and the defect detection step are known, for example, from WO 2019 / 243568 A1, the method according to the invention differs from the prior art precisely in the image acquisition step. According to the invention, the light source is linearly adjusted during the image acquisition step, and the acquisition duration of the image acquisition device is adapted such that the linear adjustment of the light source can be detected as a fringe pattern.

[0032] Within the scope of the invention, it is also provided in this case that, during the image acquisition step for shifting the fringe pattern between the individual fringe records, the light source is shifted in a second direction oriented substantially perpendicular to the first direction.

[0033] However, it has also proven advantageous to generate the fringe pattern in the individual fringe records by respectively using different light sources during the image acquisition step, and to shift the fringe pattern by using different light sources during the image acquisition step to produce the fringe pattern. If the distance between the light sources is chosen correspondingly small, the fringe pattern can be shifted without having to linearly adjust the light sources themselves for this purpose.

[0034] It has also been shown to be advantageous to record the location of detected defects during or after the defect detection step. For example, the location of detected defects can be determined relative to permanent engravings deliberately machined into test specimens during the manufacturing process. By detecting the location of defects on the test specimen and preferably storing them in a database or memory, it can be decided how to continue processing the test specimen, especially in downstream evaluation steps. Based on the defect location that can be stored in the database, for example, if the detected defect is located in the center of the test specimen or can only be used for certain production processes, it can be decided whether the test specimen of concern must be discarded. However, if the defect is located in the peripheral area of the test specimen, it can be cut out during downstream processing, for example, in the case of ophthalmic lenses, so that the test specimen does not have to be discarded, thus saving a large amount of cost. In this context, it is also contemplated to record the density of defects. The type of defect can also be recorded and, if needed, stored in a database or repository so that it can be decided whether the test specimen should be discarded or not based on the type of defect, i.e., whether the defect can be corrected, for example, by post-processing.

[0035] Further features, properties, and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings.

[0036] Figure 1 Perspective view of the test device;

[0037] Figures 2a) to 2e) Schematic view of a first embodiment of the optical carrier and a corresponding stripe recording;

[0038] Figures 3a) to 3e) Schematic view of a second embodiment of the optical carrier and a corresponding stripe recording; and

[0039] Figure 4 Flowchart of the test method according to the present invention.

[0040] Figure 1 A perspective view of a test device 1 for detecting defects in a transparent test specimen 5 is shown, which in this exemplary embodiment is formed by an ophthalmic lens. The test device 1 includes an illumination device 2 that illuminates the test specimen 5 to be inspected by transmission. Thereby, the light transmitted through the test specimen 5 is detected by an image acquisition device 3, which is designed as a camera 4 in this exemplary embodiment. To be able to illuminate the test specimen 5 by transmission, the test specimen is positioned on the observation path 6 of the image acquisition device 3 by a processing system, which is not shown in Figure 1 for the sake of clarity. To be able to detect any defects that may be present in and / or on the surface of the test specimen 5, the entire surface of the test specimen 5 is not irradiated, but rather it is irradiated with a stripe pattern 7. This stripe pattern 7 is in Figure 1implemented in the illustrated embodiment, wherein the lighting device 2 includes a plurality of light sources 8, which are formed as LEDs that can be linearly adjusted in a first direction 9. For this purpose, the light sources 8 with an equal distance D between each light source are arranged on a light carrier 11, which can be linearly moved in the first direction 9 by a first driver 12, as Figure 1 indicated by the double arrows in. The light carrier 11 extends along a second direction 10 that is substantially perpendicular to the first direction 9. If the image acquisition device 3, which is designed as a camera 4 in the illustrated example, is to take a picture of the test object without the light carrier 11 being linearly adjusted in the first direction 9, only the light spots will be captured by the camera 4. Merely adapting the acquisition duration of the image acquisition device 3 - or the exposure duration of the camera 4 - to the speed of the linear adjustment of the light carrier 11 in the first direction 9 will ultimately result in a fringe record 19. However, in order to be able to perform defect detection of the test specimen 5, additional fringe records 19 are required, in which the fringes have different positions relative to the second direction 10. In Figure 1 the illustrated embodiment, this is achieved by providing a second driver 13, which linearly adjusts the light carrier 11 in the second direction 10, as Figure 1 indicated by the double arrows in. The adjustment of the light carrier 11 in the first direction 9 and / or in the second direction 10 clearly includes linear adjustment in two opposite directions, as indicated by the double arrows in the first direction 9 and in the second direction 10. This can be used to further reduce the time required to capture the required fringe records 19. Thus, when capturing the individual fringe records 19, the light carrier 11 can be linearly adjusted alternately in the first direction 9 and in the opposite direction. In other words, the light carrier 11 can be adjusted in the first direction 9 to detect the first fringe record 19, and the light carrier can be adjusted in the opposite direction to detect the second fringe record 19. The first direction 9 and the second direction 10 are both perpendicular to each other and also perpendicular to the observation path 6.

[0041] As described above, the light sources 8 have an equal distance D between adjacent light sources 8, which is generally greater than 3 mm, preferably greater than 5 mm, and further preferably less than 12 mm, preferably less than 10 mm, and is 7 mm in this embodiment. According to the invention, the number of light sources 8 is greater than 1, preferably greater than 8, more preferably greater than 12, further preferably less than 50, preferably less than 30, and most preferably 23. Therefore, in Figure 1In the present embodiment shown, a total of 23 light sources 8 are used. The speed of the first driver 12 is greater than 1,000 mm / s, preferably greater than 2,000 mm / s, more preferably greater than 2,500 mm / s and further preferably less than 5,000 mm / s, preferably less than 4,000 mm / s, more preferably less than 3,500 mm / s and is 3,000 mm / s in the embodiment shown. Due to the acceleration of the first driver 12, this acceleration is greater than 10,000 mm / s 2 、preferably greater than 15,000 mm / s 2 、particularly preferably greater than 18,000 mm / s 2 and further preferably less than 30,000 mm / s 2 、preferably less than 25,00 mm / s 2 、particularly preferably less than 22,000 mm / s 2 、more specifically 20,000 mm / s 2 , the time until the light carrier 11 reaches the predetermined speed is so small that it can be neglected and does not have an adverse effect on the acquisition of the fringe record 19. Therefore, once the light carrier 11 moves in the first direction 9, the camera 4 can start acquiring the fringe record 19. When the linear adjustment of the light carrier 11 ends, the recording of the fringe record 19 ends. Therefore, once the light carrier 11 moves in the first direction 9, the camera 4 can start acquiring the fringe record 19. When the linear adjustment of the light carrier 11 ends, the acquisition of the fringe record 19 ends. For a typical fringe length of about 168 mm, the typical acquisition duration of the image acquisition device 3 is in the range of about 5 / 100 seconds to 6 / 100 seconds. The collimating lens 14 is arranged between the illumination device 2 and the processing system 5. The camera 4 also has a telecentric lens 15 and is connected to a control device 16, which is capable of implementing image acquisition suitable for the linear displacement of the light carrier 11 in the first direction 9 and / or the second direction 10, and which specifies the start and the duration of the image acquisition. The control device 16 also controls the first driver 12 and the second driver 13. In addition, the control device 16 includes a memory 17 and an evaluation device 18. Individual fringe records 19 can be stored in the memory, and the captured fringe records 19 are evaluated using the evaluation device. To provide sufficient stability, the test device 1 is mounted on a support 20.

[0042] Figures 2a) to 2e) shows a schematic view of the light carrier 11 according to the first embodiment, which is ultimately also used in Figure 1 the test device 1 shown. For the sake of clarity, compared with Figure 1 , only the number of light sources 8 arranged on the light carrier 11 is reduced in FIG. 2. In Figures 2a) to 2e)In [description], the optical carrier 11 is shown at the upper part of the figure in each figure, and the lower part of the figure shows a part of the fringe record 19 captured by the camera 4 in each figure, which is achieved by the linear displacement of the optical carrier 11 in the first direction 9 and the acquisition duration of the adjusted camera 4. The fringe record 19 has alternating light fringes 19.1 and dark fringes 19.2. As indicated by the arrows and as shown by the comparison of each Figures 2a) to 2e) the position of the optical carrier 11 between the respective fringe records 19 is adjusted in the second direction 10 by the second driver 13. After adjusting the position of the optical carrier 11 in the second direction 10, the next fringe record 19 can be captured by linearly adjusting the optical carrier 11 in the first direction 9, and another fringe record 19 is captured by the camera 4 simultaneously. Figures 2a) to 2e) The comparison of [description] further reveals that the position of the light fringe 19.1 then moves relative to the previously recorded fringe record 19.

[0043] In Figures 3a) to 3e) the second embodiment of the optical carrier 11 shown in the upper half of each of [description], the number of light sources 8 formed by LEDs is significantly increased, and the distance D between the respective light sources 8 is shorter compared to the first embodiment of the optical carrier 11 shown in Figures 2a) to 2e) However, during the formation of the fringe record 19, only some of the light sources 8.1 are activated in each case, while the remaining light sources 8.2 remain deactivated during the corresponding image. This is indicated by the light rays at the activated light sources 8.1 and the light rays at the deactivated light sources 8.2 shown in dark in Figure 3a to Figure 3e After the corresponding fringe record 19 has been captured, the previously active light sources 8.1 are deactivated again and the adjacent light sources 8.1 are activated, whereby the light fringe 19.1 - similar to the first embodiment - wanders in the second direction 10, but the second driver 13 does not have to be provided.

[0044] Figure 4 shows a flow chart of a test method for detecting defects of a transparent test specimen 5, in particular an ophthalmic lens, according to the invention. The method includes an image acquisition step S100, in which the image acquisition device 3 captures a plurality of fringe records 19, which are generated with the help of the lighting device 2. In this embodiment, as already referred to in Figure 1 and Figures 2a) to 2e)Explained in detail, the lighting device 2 for generating the stripe pattern 7 includes a plurality of light sources 8, which are linearly displaced in a first direction 9 by a first driver 12 during the image acquisition step S100. At the same time, in order to capture the stripe pattern 7, the acquisition duration of the image acquisition device 3 is set such that the light emitted from each linearly adjusted light source 8 is captured as a light stripe 19.1 in each case. In a preferred embodiment, between the individual stripe recordings 19, the lighting device 2 is linearly adjusted in a second direction 10 which is substantially perpendicular to the first direction 9. Furthermore, the method according to the invention includes a reconstruction step S200 and a defect detection step S300, in which the overall image is reconstructed from the stripe recordings 19 and in which defects are detected from the overall image. The detected defects are further characterized in particular by their nature and their position relative to a coordinate system, which can be defined by a permanent engraving or other markings on the test specimen 5.

[0045] List of reference signs:

[0046] 1 Test device

[0047] 2 Lighting device

[0048] 3 Image acquisition device

[0049] 4 Camera

[0050] 5 Test specimen

[0051] 6 Observation path

[0052] 7 Stripe pattern

[0053] 8 Light source

[0054] 8.1. Activated light source

[0055] 8.2. Deactivated light source

[0056] 9 First direction

[0057] 10 Second direction

[0058] 11 Light carrier

[0059] 12 First driver

[0060] 13 Second driver

[0061] 14 Collimating lens

[0062] 15 Telecentric lens

[0063] 16 Control device

[0064] 17 Memory

[0065] 18 Evaluation device

[0066] 19 Stripe recording

[0067] 19.1 Light stripe

[0068] 19.2 Dark stripe

[0069] 20 Bracket

[0070] D Distance

[0071] S100 Image acquisition step

[0072] S200 Reconstruction step

[0073] S300 Defect detection step

Claims

1. A test device for detecting defects in transparent test specimens, which transparent test specimens include ophthalmic lenses, the test device comprising: Illuminating means for transilluminating the test specimen to be inspected; and Image acquisition means for imaging the test specimen transilluminated by the illuminating means, wherein the illuminating means includes a plurality of light sources which can be linearly moved in a first direction by a first driver for generating a fringe pattern, and wherein, in order to capture the fringe pattern, the acquisition duration of the image acquisition means can be adjusted such that the light emitted by each of the light sources linearly moved in the first direction by the first driver is detected as a light fringe.

2. The test device according to claim 1, wherein, A second driver is provided for repositioning the light sources between individual fringe recordings in a second direction substantially perpendicular to the first direction.

3. The test device according to claim 2, wherein, The first direction and the second direction are each substantially perpendicular to the observation path of the image acquisition means.

4. The test device according to claim 1, wherein, The light sources are arranged on a light carrier.

5. The testing device according to claim 1, wherein, The light sources are arranged equidistantly from one another.

6. The test device according to claim 5, wherein, The distance between adjacent light sources is greater than 3 mm, or greater than 5 mm; and / or less than 12 mm, or less than 10 mm; or is 7 mm.

7. The test device according to claim 1, wherein, The number of the light sources is greater than 1, or greater than 8, or greater than 12; and / or less than 50, or less than 30; or is 23.

8. The test device according to claim 2, wherein, The speed of the first driver for moving the light sources in the first direction and / or the speed of the second driver for moving the light sources in the second direction is greater than 1,000 mm / s, or greater than 2,000 mm / s, or greater than 2,500 mm / s; and / or less than 5,000 mm / s, or less than 4,000 mm / s, or less than 3,500 mm / s; or is 3,000 mm / s.

9. The test device according to claim 2, wherein, The acceleration of the first driver and / or the acceleration of the second driver is greater than 10,000 mm / s 2 , or greater than 15,000 mm / s 2 , or greater than 18,000 mm / s 2 ; and / or less than 30,000 mm / s 2 , or less than 25,000 mm / s 2 , or less than 22,000 mm / s 2 ; or is 20,000 mm / s 2 .

10. The test device according to claim 1, wherein, The image acquisition means includes a camera with a telecentric lens.

11. A test device for detecting defects in transparent test specimens, which transparent test specimens include ophthalmic lenses, the test device comprising: Illuminating means for transilluminating the test specimen to be inspected; and Image acquisition means for imaging the test specimen transilluminated by the illuminating means, wherein the illuminating means includes a plurality of light sources arranged on a light carrier which can be linearly moved in a first direction for generating a fringe pattern, and wherein, in order to capture the fringe pattern, the acquisition duration of the image acquisition means can be adjusted such that the light emitted by each of the light sources arranged on the light carrier and linearly moved in the first direction is detected as a light fringe.

12. The test device according to claim 11, wherein, A first driver is provided for linearly moving the light sources in the first direction.

13. A test device for detecting defects in transparent test specimens, which transparent test specimens include ophthalmic lenses, the test device comprising: Illuminating means for transilluminating the test specimen to be inspected; and Image acquisition means for imaging the test specimen transilluminated by the illuminating means, Among them, the lighting device includes a plurality of point light sources, which are designed as LEDs and can linearly move in a first direction to generate a fringe pattern. And, in order to capture the fringe pattern, the acquisition duration of the image acquisition device can be adjusted such that the light emitted by each of these point light sources linearly moving in the first direction is detected as a light-colored fringe.

14. A test method for detecting defects in a transparent specimen, the transparent specimen including an ophthalmic lens, the test method comprising: (a) An image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the help of a lighting device; (b) A reconstruction step, in which an overall image is reconstructed from these fringe records; And (c) A defect detection step, in which possible defects are detected from the overall image; Among them, the lighting device for generating the fringe pattern includes a plurality of light sources, and in the image acquisition step, these light sources linearly move in a first direction through a first driver. And, in order to capture the fringe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by these linearly moving light sources is respectively detected as light-colored fringes.

15. The test method according to claim 14, wherein, In the image acquisition step for shifting the fringe pattern between respective fringe records, these light sources are shifted in a second direction substantially perpendicular to the first direction.

16. The test method according to claim 14, wherein, In the image acquisition step, different light sources are used in each case to generate the fringe pattern in respective fringe records.

17. The test method according to claim 14, wherein The defect detection step captures the positions of the identified defects.

18. A test method for detecting defects in a transparent specimen, the transparent specimen including an ophthalmic lens, the test method comprising: (a) An image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the help of a lighting device; (b) A reconstruction step, in which an overall image is reconstructed from these fringe records; And (c) A defect detection step, in which possible defects are detected from the overall image; Among them, the lighting device for generating the fringe pattern includes a plurality of light sources arranged on an optical carrier, and in the image acquisition step, these light sources linearly move in a first direction. And, in order to capture the fringe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by these linearly moving light sources is respectively detected as light-colored fringes.

19. A test method for detecting defects in a transparent specimen, the transparent specimen including an ophthalmic lens, the test method comprising: (a) An image acquisition step, in which a plurality of fringe records are captured by an image acquisition device and generated with the help of a lighting device; (b) A reconstruction step, in which an overall image is reconstructed from these fringe records; And (c) A defect detection step, in which possible defects are detected from the overall image; Wherein, the illumination device for generating the stripe pattern includes a plurality of point light sources, which are designed as LEDs and linearly move in a first direction during the image acquisition step, and wherein, in order to capture the stripe pattern, the acquisition duration of the image acquisition device is set such that the light emitted by these linearly moving light sources is respectively detected as light stripes.

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