LED unilateral oblique light source suitable for defect detection

Abstract

The invention provides an LED unilateral oblique light source suitable for defect detection, which comprises a base profile, a light-emitting module and a shell, the base profile is mounted in the shell, and the light-emitting module is mounted on the base profile; a light-emitting unit of the light-emitting module comprises an LED circuit board and an inclined block, the LED circuit board is mounted on an inclined mounting surface of the inclined block, and an included angle is formed between the inclined mounting surface and the surface to be detected; light rays emitted by the LED circuit board are emitted in the normal direction of the inclined mounting surface, and after passing through the light emitting part of the shell, the light rays irradiate the surface to be detected at an angle inclined to the surface to be detected, so that a strip-shaped effective illumination area is formed. According to the invention, by adopting the light source which is inclined in one direction, scratches and bubbles distributed along the movement direction of the plate can be clearly presented, the light field distribution of an effective illumination area does not depend on a cross geometrical relationship any more, and the installation distance of the light source can be greatly expanded, so that the problem of environmental risk caused by close-distance installation is solved.

Description

Technical Field

[0001] The present invention relates to the field of visual inspection technology, and in particular to an LED single-sided oblique light source suitable for defect detection. Background Art

[0002] With the continuous development of industrial inspection technology, machine vision plays an increasingly important role in plate surface defect detection. Among them, the design of the light source system directly determines the defect imaging quality and detection accuracy. The single cylindrical lens focusing LED line light source collimates the light emitted by the LED into a parallel beam through the cylindrical lens, which has excellent light collimation and uniform distribution characteristics. However, because the output light is ideally parallel light, when detecting linear scratches or bubbles extending along the direction of plate movement, the parallel light cannot form a sufficient light intensity gradient change at the edge of the defect, resulting in insufficient defect imaging contrast.

[0003] Bidirectional cross-oblique light sources are currently the mainstream in the market, such as the patent document with publication number CN215446100U. This light source uses two sets of symmetrically arranged line light sources to cross-irradiate at a specific angle, forming a stripe field of alternating light and dark on the surface of the plate. Scratches and bubbles distributed along the direction of movement of the plate can be clearly presented. However, bidirectional cross-oblique light sources have limitations in actual use. Since the intersection area of the light source light is the effective illumination area, the object distance requirement for the light source is relatively close. In surface inspection projects in some special industries, the light source will face the risk of enduring harsh environments such as high temperature and being hit by other objects. This is a great challenge for the light source itself. Summary of the Invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide an LED single-side oblique light source suitable for defect detection.

[0005] The LED single-side oblique light source suitable for defect detection provided by the present invention comprises a base profile, a light-emitting module and a housing, wherein the base profile is installed inside the housing, and the light-emitting module is installed on the base profile;

[0006] The light-emitting unit of the light-emitting module includes an LED circuit board and an inclined block, the LED circuit board is mounted on an inclined mounting surface of the inclined block, and an angle exists between the inclined mounting surface and the surface to be detected;

[0007] The light-emitting module includes multiple light-emitting units, and the light emitted by the multiple light-emitting units is emitted along the normal direction of the inclined mounting surface to form a single-sided inclined light, and is emitted from the light-emitting portion of the shell. The light is irradiated to the surface to be detected at an angle inclined to the surface to be detected, forming a strip-shaped effective lighting area.

[0008] Preferably, the light emitting module comprises a plurality of light emitting units arranged in parallel, and the light emitted by the plurality of light emitting units is inclined toward the same side, forming a continuous and uninterrupted effective lighting area.

[0009] Preferably, the housing comprises a side plate, a first end cover and a second end cover;

[0010] The first end cover and the second end cover are respectively installed at two ends of the base profile, and the side panels are installed in pairs at both sides of the base profile.

[0011] Preferably, an aviation plug connector and a quick-connect connector are installed at the bottom of the first end cover and / or the second end cover.

[0012] Preferably, the top of the housing is a hollow light-emitting portion, a light-transmitting substrate is installed in the light-emitting portion, and the side of the light-transmitting substrate is arranged on the step of the side plate and fixed by a pressing sheet;

[0013] The light emitted by the light emitting module is emitted to the surface to be detected through the light-transmitting substrate.

[0014] Preferably, a first heat conducting sheet is provided between the light emitting module and the base profile, and the first heat conducting sheet is attached to the bottom of each light emitting unit of the light emitting module.

[0015] Preferably, the light emitting unit comprises an inclined block, a mounting plate, a cover plate, an LED circuit board, a lens and a transparent round rod;

[0016] The mounting plate is mounted on the base profile in a direction parallel to the base profile, the inclined block is mounted on the mounting plate through its horizontal mounting surface, and the cover plate is mounted on the top surface of the inclined block;

[0017] The LED circuit board is covered with a lens, and the transparent round rod is fixedly installed between the end of the mounting plate and the end of the cover plate and is located outside the lens;

[0018] The light emitted by the LED circuit board is emitted to the lens, and after the primary light distribution of the lens, it is emitted to the transparent round rod for secondary light distribution. After the secondary light distribution, the light is emitted from the light output part of the shell and irradiates the surface to be detected.

[0019] Preferably, the LED circuit board is a strip-shaped structure, on which a plurality of LED lamp beads are arranged in parallel, and the LED circuit board is arranged along the length direction of the inclined mounting surface of the inclined block;

[0020] The lens is a strip structure matching the LED circuit board, on which a plurality of aspheric lenses are arranged in parallel. The lenses are fixedly mounted on the inclined mounting surface of the inclined block through fixing columns.

[0021] Preferably, a second heat conducting sheet is provided between the LED circuit board and the inclined mounting surface of the oblique block, and the second heat conducting sheet is attached to the bottom of each LED lamp bead of the LED circuit board.

[0022] Preferably, there are multiple light-emitting units, and the mounting plates of the multiple light-emitting units are connected end to end and mounted on the base profile along the length direction;

[0023] The top surface of the inclined block is perpendicular to the inclined mounting surface, the cover plate is parallel to the light emitting direction, and among adjacent light emitting units, the bottom end of the transparent round rod of the rear light emitting unit is higher than the rear end of the cover plate of the front light emitting unit.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. By adopting a unidirectional inclined light source, the present invention can clearly present scratches and bubbles distributed along the movement direction of the plate, and the light field distribution in the effective illumination area no longer depends on the cross-geometric relationship. The installation distance of the light source can be greatly expanded, thereby solving the environmental risk problem caused by close-range installation.

[0026] 2. The present invention can highlight measurement features, simplify image processing algorithms, overcome the interference of ambient light, ensure image stability, improve image signal-to-noise ratio, and enable software algorithms to clearly identify defects on the surface of the plate, such as longitudinal scratches and bubbles, thereby improving the detection rate of defects and reducing false detections and missed detections due to unstable image quality. It has high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 Schematic diagram of the explosion of the light emitting module in the present invention;

[0030] Figure 3 It is an explosion diagram of the present invention;

[0031] Figure 4 Schematic diagram of the detection results of the present invention.

[0032] The figure shows:

[0033] Base profile 1 Lens 47

[0034] Side panel 2 fixed column 48

[0035] First heat conducting sheet 3 transparent round rod 49

[0036] Light-emitting module 4 Light-transmitting substrate 5

[0037] Mounting plate 41 Pressing piece 6

[0038] Inclined block 42 First end cover 7

[0039] Cover plate 43 Second end cover 8

[0040] Second heat conducting sheet 44 Aviation plug connector 9

[0041] First LED circuit board 45 Quick connector 10

[0042] Second LED circuit board 46 DETAILED DESCRIPTION

[0043] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0044] The present invention discloses an LED single-sided oblique light source suitable for defect detection. By adopting a unidirectionally inclined light source, scratches and bubbles distributed along the movement direction of the plate can be clearly presented, and the light field distribution in the effective illumination area no longer depends on the cross-geometric relationship. The installation distance of the light source can be greatly expanded, thereby solving the environmental risk problem caused by close-range installation.

[0045] According to the present invention, the LED single-side oblique light source suitable for defect detection is provided, such as Figure 1-3 As shown. It includes a base profile 1, a light-emitting module 4, and a housing. The base profile 1 is installed inside the housing, and the light-emitting module 4 is installed on the base profile 1. The light-emitting unit of the light-emitting module 4 includes an LED circuit board and an inclined block 42. The LED circuit board is installed on the inclined mounting surface of the inclined block 42. There is an angle between the inclined mounting surface and the surface to be detected.

[0046] The light-emitting module 4 includes a plurality of light-emitting units arranged in parallel. The light emitted by the plurality of light-emitting units is emitted along the normal direction of the inclined mounting surface, inclined toward the same side to form a unilaterally inclined light, and emitted from the light-emitting portion of the shell. The light is irradiated onto the surface to be detected at an angle inclined to the surface to be detected, forming a continuous and uninterrupted strip-shaped effective lighting area.

[0047] The present invention uses multiple light-emitting units that can emit unidirectional inclined light to form an effective illumination area without relying on cross-geometric relationships, thereby expanding the object distance range. Taking the defect detection of stainless steel plates as an example, Figure 4 The figure shows the images of scratches and bubbles on the plate surface collected when the present invention is used for defect detection. It can be seen from the figure that sufficient light intensity gradient changes can be formed at the edge of the defect, thereby obtaining a higher defect imaging contrast, which is convenient for subsequent software algorithm recognition.

[0048] like Figure 3 As shown, the shell includes a side panel 2, a first end cover 7 and a second end cover 8; the first end cover 7 and the second end cover 8 are respectively installed at the two ends of the base profile 1, and the side panels 2 are installed in pairs on both sides of the base profile 1. An aviation plug connector 9 and a quick-connect connector 10 are installed at the bottom of the first end cover 7 and / or the second end cover 8. The top of the shell is a hollow light-emitting portion, in which a light-transmitting substrate 5 is installed. The side of the light-transmitting substrate 5 is arranged on the step of the side panel 2 and is fixed by a pressing piece 6; the light emitted by the light-emitting module 4 is emitted to the surface to be detected through the light-transmitting substrate 5. Among them, the light-transmitting substrate 5 is preferably ultra-white tempered glass.

[0049] In a preferred example, in order to achieve good heat dissipation performance, a first heat conducting sheet 3 is provided between the light emitting module 4 and the base profile 1 , and the first heat conducting sheet 3 is attached to the bottom of each light emitting unit of the light emitting module 4 .

[0050] In a preferred embodiment, Figure 2 As shown, the light-emitting unit includes an inclined block 42, a mounting plate 41, a cover plate 43, an LED circuit board, a lens 47 and a transparent round rod 49; the mounting plate 41 is installed on the base profile 1 in a direction parallel to the base profile 1, the inclined block 42 is installed on the mounting plate 41 through its horizontal mounting surface, and the cover plate 43 is installed on the top surface of the inclined block 42; the LED circuit board is covered with a lens 47, and the transparent round rod 49 is fixedly installed between the end of the mounting plate 41 and the end of the cover plate 43, and is located on the outside of the lens 47; the light emitted by the LED circuit board is emitted to the lens 47, and after the primary light distribution of the lens 47, it is emitted to the transparent round rod 49 for secondary light distribution. The light after the secondary light distribution is emitted from the light emitting part of the shell and irradiates the surface to be detected.

[0051] In a preferred embodiment, two rows of LED circuit boards are installed on the oblique block 42, namely the first LED circuit board 45 and the second LED circuit board 46; the LED circuit board is a strip structure, on which a plurality of LED lamp beads are arranged side by side, and the LED circuit board is arranged along the length direction of the inclined mounting surface of the oblique block 42; the ultra-bright LED particles on the circuit board are arranged in a single row, centered and compactly, thereby ensuring the brightness and uniformity of the light source; the lens 47 is a strip structure that matches the LED circuit board, on which a plurality of aspheric lenses are arranged side by side, and the lens 47 is fixedly mounted on the inclined mounting surface of the oblique block 42 by a fixing column 48. The present invention uses dual lenses for light distribution. The aspheric lens close to the circuit board performs primary light distribution, which improves the utilization rate of LED light output; the transparent round rod away from the circuit board performs secondary light distribution to achieve light convergence;

[0052] In a preferred example, in order to achieve good heat dissipation performance, a second heat conducting plate 44 is provided between the LED circuit board and the inclined mounting surface of the inclined block 42 , and the second heat conducting plate 44 is attached to the bottom of each LED lamp bead of the LED circuit board.

[0053] In a preferred embodiment, Figure 3 As shown, there are multiple light-emitting units, and the mounting plates 41 of the multiple light-emitting units are connected end to end and installed on the base profile 1 along the length direction. The top surface of the inclined block 42 is perpendicular to the inclined mounting surface, and the cover plate 43 is parallel to the light emission direction. Among adjacent light-emitting units, the bottom end of the transparent round rod 49 of the rear light-emitting unit is higher than the rear end of the cover plate 43 of the front light-emitting unit. This ensures that when light is emitted, the light emitted by the light-emitting unit on the rear side is not blocked by the light-emitting unit on the front side, thereby forming a dark area.

[0054] In a preferred embodiment, an embedded control module is integrated inside the second end cap 8, which includes a light intensity sensor array, a microprocessor, and a PWM dimming circuit. The light intensity sensor array is composed of a plurality of photodiodes, which are arranged at equal intervals along the length of the light-emitting portion at the inner edge of the light-transmitting substrate 5 to monitor the illuminance distribution of the effective lighting area in real time. The microprocessor dynamically adjusts the driving current of each light-emitting unit by analyzing the sensor feedback data: when it is detected that the illuminance attenuation in a local area exceeds the set threshold, the driving power of the LED circuit board in the corresponding light-emitting unit is automatically increased, and the light intensity is fine-tuned through PWM dimming. This design can improve the uniformity of illuminance in the effective area and is suitable for the detection of composite materials with large differences in reflectivity.

[0055] The assembly steps of the present invention are:

[0056] Step 1: Make the light-emitting module 4. Use screws to fix the inclined block 42 on the top of the mounting plate 41. Place a second heat-conducting sheet 44 on the inclined block 42. Place the first LED circuit board 45 and the second LED circuit board 46 on the second heat-conducting sheet 44. Place the fixing column 48 on the LED circuit board. Screws pass through the fixing column 48 to fix the LED circuit board and the aspheric lens 47. Place the transparent round rod 49 in the groove of the mounting plate 41. Place the cover plate 43 on the inclined block 42 and use it to press the transparent round rod 49.

[0057] Step 2: Lay a first heat conducting sheet 3 on the heat dissipation profile, i.e., the base profile 1, place the light emitting module 4 on the first heat conducting sheet 3, and fasten it with screws, so that the modules are connected in parallel;

[0058] Step 3: Fix the side panels 2 on both sides of the heat dissipation profile;

[0059] Step 4: Fix the first end cap 7 and the second end cap 8 to the two ends of the heat dissipation profile, fix the aviation plug connector 9 and the quick connector 10 to the bottom of the second end cap 8, and connect the aviation plug connector 9 to the terminal wire inside the light source;

[0060] Step 5: Place the ultra-clear tempered glass on the step between the two side panels 2 and fix both sides with L-shaped pressing pieces 6. There are sealing strips between the pressing piece and the glass, and between the glass and the step to prevent dust and provide buffering.

[0061] Step 6: The high-power LED single-side oblique light source suitable for defect detection is manufactured, and then aging test and uniformity test are carried out;

[0062] Step 7: Install the embedded control module, embed the flexible circuit board of the light intensity sensor array into the edge slot of the light-transmitting substrate 5, and connect it to the microprocessor in the second end cover 8;

[0063] Specifically, of the two optical lenses, the aspheric lens 47 is close to the LED circuit board, and the transparent round rod 49 is far away from the LED circuit board. The number of cylindrical mirrors on the aspheric lens 47 is the same as the number of LED lamp beads, and the arc diameter of the cylindrical mirror is four twenty-fifths of the diameter of the transparent round rod 49; the angle between the bottom plane of the LED circuit board and the horizontal plane ranges from 0° to 90°, and is parallel to the axis of the bottom plane of the aspheric lens 47 and the transparent round rod 49.

[0064] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0065] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. An LED single-side oblique light source suitable for defect detection, characterized in that: It comprises a base profile (1), a light-emitting module (4) and a housing, wherein the base profile (1) is installed inside the housing, and the light-emitting module (4) is installed on the base profile (1); The light-emitting module (4) has a light-emitting unit comprising an LED circuit board and an inclined block (42); the LED circuit board is mounted on an inclined mounting surface of the inclined block (42); an angle exists between the inclined mounting surface and the surface to be detected; The light emitting module (4) comprises a plurality of light emitting units, and the light emitted by the plurality of light emitting units is emitted along the normal direction of the inclined mounting surface to form a single-sided inclined light, and is emitted from the light emitting portion of the housing. The light is irradiated onto the surface to be detected at an angle inclined to the surface to be detected, forming a strip-shaped effective illumination area.

2. The LED single-side oblique light source suitable for defect detection according to claim 1, characterized in that: The light-emitting module (4) comprises a plurality of light-emitting units arranged in parallel, and the light emitted by the plurality of light-emitting units is inclined toward the same side, forming a continuous and uninterrupted effective lighting area.

3. The LED single-side oblique light source suitable for defect detection according to claim 1, characterized in that: The housing comprises a side plate (2), a first end cover (7) and a second end cover (8); The first end cover (7) and the second end cover (8) are respectively installed at the two ends of the base profile (1), and the side panels (2) are installed in pairs on both sides of the base profile (1).

4. The LED single-side oblique light source suitable for defect detection according to claim 3, characterized in that: An aviation plug connector (9) and a quick-connect connector (10) are installed at the bottom of the first end cover (7) and / or the second end cover (8).

5. The LED single-side oblique light source suitable for defect detection according to claim 3, characterized in that: The top of the housing is a hollow light-emitting portion, a light-transmitting substrate (5) is installed in the light-emitting portion, and the side of the light-transmitting substrate (5) is arranged on the step provided by the side plate (2) and is fixed by a pressing sheet (6); The light emitted by the light-emitting module (4) is emitted to the surface to be detected through the light-transmitting substrate (5).

6. The LED single-side oblique light source suitable for defect detection according to claim 1, characterized in that: A first heat conducting sheet (3) is provided between the light-emitting module (4) and the base profile (1), and the first heat conducting sheet (3) is attached to the bottom of each light-emitting unit of the light-emitting module (4).

7. The LED single-side oblique light source suitable for defect detection according to claim 2, characterized in that: The light-emitting unit comprises an inclined block (42), a mounting plate (41), a cover plate (43), an LED circuit board, a lens (47) and a transparent round rod (49); The mounting plate (41) is mounted on the base profile (1) in a direction parallel to the base profile (1), the inclined block (42) is mounted on the mounting plate (41) via its horizontal mounting surface, and the cover plate (43) is mounted on the top surface of the inclined block (42); The LED circuit board is covered with a lens (47), and the transparent round rod (49) is fixedly mounted between the end of the mounting plate (41) and the end of the cover plate (43), and is located outside the lens (47); The light emitted by the LED circuit board is emitted to the lens (47), and after the primary light distribution of the lens (47), it is emitted to the transparent round rod (49) for secondary light distribution. After the secondary light distribution, the light is emitted from the light emitting portion of the shell and irradiated to the surface to be detected.

8. The LED single-side oblique light source suitable for defect detection according to claim 7, characterized in that: The LED circuit board is a strip-shaped structure, on which a plurality of LED lamp beads are arranged in parallel, and the LED circuit board is arranged along the length direction of the inclined mounting surface of the inclined block (42); The lens (47) is a strip-shaped structure matching the LED circuit board, on which a plurality of aspheric lenses are arranged in parallel. The lens (47) is fixedly mounted on the inclined mounting surface of the inclined block (42) via a fixing column (48).

9. The LED single-side oblique light source suitable for defect detection according to claim 8, characterized in that: A second heat conducting sheet (44) is provided between the LED circuit board and the inclined mounting surface of the inclined block (42), and the second heat conducting sheet (44) is attached to the bottom of each LED lamp bead of the LED circuit board.

10. The LED single-side oblique light source suitable for defect detection according to claim 7, characterized in that: There are multiple light-emitting units, and the mounting plates (41) of the multiple light-emitting units are connected end to end and mounted on the base profile (1) along the length direction; The top surface of the inclined block (42) is perpendicular to the inclined mounting surface, the cover plate (43) is parallel to the light emission direction, and among adjacent light-emitting units, the bottom end of the transparent round rod (49) of the rear light-emitting unit is higher than the rear end of the cover plate (43) of the front light-emitting unit.

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