Circuit board detection clamping device and operation method thereof

Abstract

The invention relates to the technical field of circuit board detection, in particular to a circuit board detection clamping device and an operation method thereof. The device comprises a bearing base with an opening and a first clamping module pair, and the module pair comprises a fixed side clamping mechanism and a sliding side clamping mechanism. Each mechanism has a lower carrier and an upper clamping unit to clamp the edge of the PCB. The sliding side mechanism is connected with the first tension displacement module and can be driven to be away from the fixed side so as to apply tensile tension to the PCB to flatten the PCB. A second clamping module can be arranged to perform biaxial stretching, and an ejector rod and a movable supporting module are included to assist in positioning and supporting. According to the invention, the PCB surface deformation can be actively corrected, and the detection precision is improved.

Description

Technical Field

[0001] This invention relates to the field of circuit board testing technology, and in particular to a circuit board testing clamping device and its operating method. Background Technology

[0002] As electronic products become thinner and smaller, the thickness of printed circuit boards (PCBs) continues to decrease, and their rigidity also weakens. When performing optical scanning or electrical testing on these thin PCBs, they must be supported on a testing stage. To accommodate back-drilling processes and avoid backlight interference, the testing stage is usually designed with an open structure in the center. This means that only the edges of the PCB are supported, and the central area is prone to denting or bending due to its own weight.

[0003] Existing technologies mainly rely on passive support and lack active correction methods for board surface deformation. Uneven board surface can cause optical inspection systems to lose focus or result in poor contact of test probes, severely restricting inspection accuracy and yield, and becoming a key technical bottleneck in the manufacturing of high-density, thin PCBs. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the present invention aims to solve the problem of decreased detection accuracy caused by the sagging deformation due to the central suspended support during the inspection of ultra-thin printed circuit boards.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a circuit board inspection and clamping device, comprising: a support base having a base opening; and a first clamping module pair disposed on the support base and including a first clamping mechanism and a second clamping mechanism disposed opposite to each other, wherein the first clamping mechanism and the second clamping mechanism are respectively located on opposite sides of the base opening; the first clamping mechanism is fixed on the support base, and the second clamping mechanism is slidably disposed on the support base; both the first clamping mechanism and the second clamping mechanism include a lower support member and an upper clamping unit disposed opposite to the lower support member, the upper clamping unit being movable relative to the lower support member to clamp and fix the printed circuit board together with the lower support member; the second clamping mechanism is connected to a first tension displacement module, the first tension displacement module being used to drive the second clamping mechanism to move in a direction away from the first clamping mechanism, thereby applying tensile tension to the printed circuit board.

[0007] As a preferred embodiment of the circuit board detection clamping device of the present invention, it further includes: a second clamping module pair, wherein the first clamping module pair is arranged along a first axial direction, and the second clamping module pair is arranged along a second axial direction perpendicular to the first axial direction; the first clamping module pair and the second clamping module pair are used to perform biaxial stretching of the printed circuit board along the first axial direction and the second axial direction, and the first clamping module pair and the second clamping module pair can be operated sequentially to apply tensile tension to the printed circuit board; the second clamping module pair is connected to a second tension displacement module, which is used to drive the second clamping module pair to move along the second axial direction to apply tensile tension to the printed circuit board.

[0008] In a preferred embodiment of the circuit board inspection clamping device of the present invention, the first tension displacement module includes a transmission belt and a slide disposed on the transmission belt; the lower bearing member of the second clamping mechanism is connected to the upper clamping unit and the slide to move synchronously with the slide.

[0009] As a preferred embodiment of the circuit board inspection and clamping device of the present invention, it further includes a top rod, which is vertically and flexibly disposed in the base opening of the bearing base; the top rod can be moved to be flush with the bearing surface of the lower bearing member to assist in positioning the printed circuit board.

[0010] As a preferred embodiment of the circuit board inspection clamping device of the present invention, it further includes: an inspection module disposed on one side of the support base for inspecting the printed circuit board; and a movable support module disposed at the base opening of the support base and including at least one support crossbar; the support crossbar is movable relative to the inspection module to switch between supporting the printed circuit board and avoiding the inspection path of the inspection module.

[0011] The present invention also provides an operation method for a circuit board inspection and clamping device, applicable to the circuit board inspection and clamping device, comprising the following steps: placing a printed circuit board on the support base, and positioning the opposite two sides of the printed circuit board to correspond to the first clamping mechanism and the second clamping mechanism respectively; placing the printed circuit board on the lower support member, and driving the upper clamping unit to move relative to the lower support member to clamp and fix the printed circuit board together with the lower support member; activating the first tension displacement module to drive the second clamping mechanism to move in a direction away from the first clamping mechanism, thereby applying tensile tension to the printed circuit board.

[0012] As a preferred embodiment of the operation method of the circuit board detection clamping device of the present invention, the circuit board detection clamping device further includes a second clamping module pair arranged along the second axis; the operation method further includes: after or simultaneously with the first clamping module pair applying a first axial tensile tension to the printed circuit board, activating a second tension displacement module to drive the second clamping module pair to move along the second axis, applying a second axial tensile tension to the printed circuit board, thereby achieving biaxial tension.

[0013] In a preferred embodiment of the operation method of the circuit board detection clamping device of the present invention, in the step of placing the printed circuit board on the lower support member, the top rod, which is movably disposed in the opening of the base, is first raised so that its top surface is flush with the bearing surface of the lower support member to assist in positioning the printed circuit board; after clamping and fixing the printed circuit board, the top rod is lowered.

[0014] In a preferred embodiment of the operation method of the circuit board inspection clamping device of the present invention, the printed circuit board is inspected using an inspection module disposed on one side of the bearing base; during the inspection process, the position of the support crossbar of the movable support module is controlled so that it moves to provide support under the printed circuit board when needed, and moves away to avoid the inspection path of the inspection module.

[0015] The beneficial effects of this invention are as follows: By incorporating a sliding clamping mechanism and a tension displacement module, after firmly clamping the PCB edge, this invention can actively apply horizontal tensile tension to forcibly flatten the board surface that is sagging due to its own weight, fundamentally eliminating the impact of board bending or dents on detection accuracy. Through the sequential stretching of the dual-axis clamping module, uniform and controllable bidirectional leveling can be achieved, avoiding stress concentration damage to the board. The cooperation between the top rod and the movable support module further ensures the overall flatness and stability during the loading, unloading, and dynamic detection processes. This device has a compact structure and a high degree of automation, significantly improving the alignment accuracy, signal stability, and overall yield of ultra-thin PCBs in optical and electrical testing. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a top view of a traditional testing device supporting a printed circuit board.

[0018] Figure 2 for Figure 1 The diagram shows a cross-sectional view of a conventional testing device and a printed circuit board along its section line 2-2.

[0019] Figure 3 This is a three-dimensional schematic diagram of the combination of multiple circuit board detection clamping devices of the present invention.

[0020] Figure 4 for Figure 3 A magnified 3D view of a single circuit board inspection clamping device.

[0021] Figure 5 This is an exploded perspective view of the support base and printed circuit board of the present invention.

[0022] Figure 6 This is a top view of the printed circuit board supported and clamped by the base of the present invention.

[0023] Figure 7 This is an exploded perspective view of the bearing base, clamping module, and tension displacement module of the present invention.

[0024] Figure 8 For the present invention Figure 6 A cross-sectional view of the device and circuit board along section line 8-8.

[0025] Figure 9 This is a cross-sectional schematic diagram of the clamping unit releasing the printed circuit board in this invention.

[0026] Figure 10 and Figure 11 This is a schematic diagram of the bearing base and top rod under different working conditions according to another embodiment of the present invention.

[0027] Figure 12 This is a three-dimensional layout diagram of the bearing base, detection module, and movable support module according to another embodiment of the present invention.

[0028] Figure 13 and Figure 14 This is a three-dimensional schematic diagram of the bearing base and movable support module in different states according to another embodiment of the present invention.

[0029] Figure 15 This is a bottom view of the support base, movable support module, and supported printed circuit board according to another embodiment of the present invention.

[0030] Figure 16 This is a flowchart illustrating the operation method of the circuit board detection clamping device of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive, either alone or selectively, with other embodiments.

[0034] Example 1, referring to Figures 1-15 The circuit board inspection clamping device 100 provided in the first embodiment of the present invention mainly includes a support base 110 and a first clamping module pair 120 disposed thereon. The support base 110 serves as the supporting body of the device, and has a base opening 112 in its central area. This opening provides the necessary working space for inspection components such as backlight sources, vision cameras, or test probes above, which is a common design for back-drilled process boards. The first clamping module pair 120 includes two clamping mechanisms arranged opposite to each other: a first clamping mechanism 122 and a second clamping mechanism 124. They are arranged on opposite sides of the base opening 112, for example, on the left and right sides of the opening, respectively. The first clamping mechanism 122 is fixedly mounted on the support base 110 by fasteners, forming a fixed clamping reference; the second clamping mechanism 124 is slidably mounted on the support base 110 by a linear guide slider assembly, allowing it to move linearly in a direction parallel to the support base surface. The first clamping mechanism 122 and the second clamping mechanism 124 have the same clamping unit structure, both including a lower support member A and an upper clamping unit B. The upper surface of the lower support member A forms a flat support surface for supporting the edge of the printed circuit board 200; the upper clamping unit B is mounted directly above the lower support member A by a vertically arranged drive member (such as a cylinder or electric cylinder), and can perform vertical lifting and lowering movements. The lower pressing surface of the upper clamping unit B is usually provided with elastic pads or anti-slip textures to ensure firm clamping without damaging the board surface. The second clamping mechanism 124 is drivenly connected to a first tension displacement module 126. The first tension displacement module 126 can be a precision linear drive mechanism, such as including a servo motor, a synchronous belt drive assembly 125, and a slide 127 fixed to the synchronous belt. The base of the second clamping mechanism 124 is fixedly connected to the slide 127, so that the whole can be driven by the synchronous belt.

[0035] The basic operation method of the device is as follows. First, the operator or robot moves the printed circuit board 200 to be inspected horizontally above the support base 110 and lowers it, so that the left and right edges of the circuit board fall onto the lower support members A of the first clamping mechanism 122 and the second clamping mechanism 124, respectively. At this time, since the area of ​​the base opening 112 is suspended, the middle part of the circuit board may have sagged naturally. Next, the upper clamping units B of the first clamping mechanism 122 and the second clamping mechanism 124 are pressed down simultaneously, working together with their respective lower support members A to firmly clamp the two edges of the printed circuit board 200. After reliable clamping is completed, the first tension displacement module 126 is activated. The motor drives the synchronous belt to move, driving the slide 127 and the entire second clamping mechanism 124 fixed thereto, in a direction away from the first clamping mechanism 122 (i.e., Figure 6 As shown in the diagram, the circuit board moves precisely a short distance in the horizontal outward direction. Since the left side of the circuit board is completely fixed by the first clamping mechanism 122, and the right side is pulled outward by the second clamping mechanism 124, the entire board surface is subjected to a uniform tensile tension in the horizontal plane. This actively applied tension effectively overcomes the material's own deflection deformation, "tightening" and "flattening" the core area of ​​the board that has sagged due to gravity, restoring it to a flat state that meets the testing requirements. This process completely changes the situation where traditional stages can only passively support the board; by actively correcting deformation through mechanical tension, it provides a flat and stable reference plane for subsequent high-precision optical scanning or electrical testing.

[0036] To achieve a better two-dimensional leveling effect on the printed circuit board and prevent residual warping in another direction after unidirectional stretching, this invention further introduces a second clamping module 130 on top of the aforementioned basic device, such as... Figure 3 , Figure 4 and Figure 6 As shown. The second clamping module pair 130 is arranged along a second axis D2 perpendicular to the first clamping module pair 120 (first axis D1). It also includes a pair of opposing clamping mechanisms arranged on the other two sides (e.g., front and rear sides) of the base opening 112. The structure of the second clamping module pair 130 can be similar to that of the first clamping module pair 120, with at least one side of its clamping mechanism being a sliding design and connected to an independent second tension displacement module 136 for driving. In actual operation, a step-by-step sequential stretching strategy can be adopted to optimize stress distribution. For example, the first clamping module pair 120 first performs clamping and stretching in the X-axis direction, flattening the circuit board in the X direction and maintaining tension; then, the second clamping module pair 130 performs clamping and stretching in the Y-axis direction. This sequential biaxial stretching avoids local stress concentration or complex distortion of the board material that may be caused by simultaneous force on all four sides, making the leveling process more stable and controllable, and ultimately obtaining a board surface with extremely high overall flatness.

[0037] When placing an extremely thin or large printed circuit board 200, to ensure that it can be placed stably and accurately on the lower support A without excessive drooping due to the middle being suspended, which would cause placement difficulties or positioning deviations, a preferred embodiment of the present invention provides at least one liftable top rod 140 within the base opening 112 of the support base 110. Figure 10 and Figure 11 As shown. The top rod 140 is driven by a lower lifting drive (such as a cylinder or linear motor) and can move up and down vertically. In the initial loading stage, the top rod 140 rises, and its top support surface moves to a height that is coplanar with the support surfaces of all the lower support components A, thus forming a complete temporary support plane together with the surrounding lower support components A. Operators or robots can place the printed circuit board 200 smoothly on this composite plane, achieving rapid and accurate initial positioning, effectively preventing the circuit board from getting stuck in the opening or tilting before it is clamped. After the first clamping module pair 120 and the second clamping module pair 130 have reliably clamped the edge of the circuit board, the top rod 140 descends under the command of the control system, and its top surface drops below the bottom surface of the circuit board, thus completely clearing the space below the base opening 112 and ensuring that the detection light or probes are not obstructed. This top rod mechanism significantly improves the smoothness and positioning accuracy of the loading process, and is especially suitable for automated production lines.

[0038] To further ensure that the circuit remains flat throughout the inspection process after stretching and leveling, especially for thin circuit boards with large spans, and to simultaneously meet the requirement of unobstructed scanning by the inspection module, the device of this invention can also integrate a movable support module 160, such as... Figures 12 to 15 As shown. The active support module 160 is located within the base opening 112 of the support base 110 and typically includes one or more independently driveable support crossbars 162. The support crossbars 162 are driven by a lateral drive mechanism (such as another set of motors and linear modules) and can reciprocate along a direction parallel to the support base surface (e.g., the X-axis or Y-axis). Its working principle is dynamic and intelligent: during the scanning of the printed circuit board 200 by the detection module 150 (e.g., an AOI camera), the support crossbars 162 will move in coordination according to the real-time detection path. When the detection module 150 moves to a certain area of ​​the circuit board to take a picture, the support crossbars 162 located directly below that area will move laterally in advance to make room for the camera's field of view and avoid image obstruction; once the detection module 150 moves past that area, the support crossbars 162 can quickly move back under the circuit board to provide continuous auxiliary support and prevent slight rebound deformation due to large spans. This combination of "dynamic avoidance" and "following support" perfectly resolves the contradiction between "full support to ensure flatness" and "partial avoidance to meet detection requirements," achieving optimized coordination between support and detection in space and time.

[0039] Example 2, refer to Figure 16 This embodiment provides an operation method for the aforementioned circuit board inspection clamping device. This method aims to achieve active stretching, leveling, and efficient inspection of the printed circuit board 200 through a series of orderly and coordinated control steps. The execution entity of this method can be a programmable logic controller (PLC) or an industrial computer electrically connected to the device. The method begins at step S1: the printed circuit board 200 to be inspected is placed on a support base 110 with a base opening 112. In this step, it is necessary to ensure that the opposite two sides of the circuit board (e.g., the left and right sides) are aligned and prepared for placement on the lower support members A of the first clamping mechanism 122 and the second clamping mechanism 124. To assist in achieving accurate and stable placement, especially for easily deformable thin boards, the liftable top rod 140 provided in the base opening 112 can be raised in advance, adjusting its top surface to the same horizontal level as the bearing surfaces of all lower support members A, forming a complete temporary support platform on which the circuit board 200 can be placed stably. Next, step S2 is performed: the upper clamping unit B of the first clamping mechanism 122 and the second clamping mechanism 124 is moved downward relative to their respective lower support members A, thereby firmly clamping and fixing the two sides of the printed circuit board 200 between the lower support member A and the upper clamping unit B. Reliable clamping is the basis for subsequent tension application. Then, the core step S3 is executed: the first tension displacement module 126 connected to the second clamping mechanism 124 is activated. This module (e.g., its internal motor-driven synchronous belt drive) precisely moves the second clamping mechanism 124 as a whole along a direction away from the first clamping mechanism 122 (i.e., outward) by a set displacement. Since one side of the circuit board (the first clamping mechanism side) is fixed, and the other side (the second clamping mechanism side) is pulled outward, a horizontal tensile tension is applied to the entire printed circuit board 200. This tension effectively flattens the board surface, correcting any initial sag or bend.

[0040] This method of operation can be further extended to achieve better biaxial tension leveling when the apparatus used also includes a second pair of clamping modules 130 arranged along the second axis D2. After or in coordination with the clamping and first axial tension of the first clamping module pair 120, a second tension displacement module 136 connected to the second clamping module pair 130 can be activated. This module drives the second clamping module pair 130 to move along the second axis D2, thereby applying tensile tension in a second direction to the printed circuit board 200. In actual control, a sequential action strategy is usually adopted, that is, first completing the tension in one axis (such as the X-axis) and maintaining the tension, and then starting the tension in another axis (such as the Y-axis), to avoid the adverse effects that multi-directional stress may have on the board material if applied simultaneously. After the sub-step regarding the placement of the circuit board in step S2 is completed, and before or during the start of step S3, an auxiliary step can be performed: the previously raised top rod 140 for auxiliary positioning is lowered so that its top is lowered below the lower surface of the printed circuit board 200, thereby making unobstructed space for the detection operation below the base opening 112. After the entire leveling process is completed, the inspection stage begins. In this stage, an inspection module 150, located on one side of the support base 110, scans and inspects the flattened printed circuit board 200 (e.g., optical imaging or electrical testing). Simultaneously with the inspection, a dynamic support coordination step is executed: based on the real-time movement path and position of the inspection module 150, the control system intelligently controls the movement of the support crossbar 162 of the movable support module 160. When the inspection module 150 is about to scan a certain area, the support crossbar 162 is moved laterally away from below that area to avoid obstruction, ensuring an unobstructed inspection view or test path. After the inspection module 150 leaves the area, the support crossbar 162 is moved back to the area below the circuit board to provide support, maintaining the overall flatness of the board surface and preventing new deformation due to prolonged suspension or stress. Through the organic combination and sequential control of the above steps, this method systematically solves the problem of maintaining the flatness of thin circuit boards during the inspection process, significantly improving the accuracy and reliability of the inspection.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A circuit board inspection clamping device, characterized in that: include, A support base (110) having a base opening (112); as well as The first clamping module pair (120) is disposed on the bearing base (110) and includes a first clamping mechanism (122) and a second clamping mechanism (124) disposed opposite to each other. The first clamping mechanism (122) and the second clamping mechanism (124) are respectively located on opposite sides of the base opening (112); The first clamping mechanism (122) is fixed on the bearing base (110), and the second clamping mechanism (124) is slidably disposed on the bearing base (110); Both the first clamping mechanism (122) and the second clamping mechanism (124) include a lower support member (A) and an upper clamping unit (B) disposed opposite to the lower support member (A). The upper clamping unit (B) can move relative to the lower support member (A) to clamp and fix the printed circuit board (200) together with the lower support member (A). The second clamping mechanism (124) is connected to a first tension displacement module (126), which is used to drive the second clamping mechanism (124) to move in a direction away from the first clamping mechanism (122), thereby applying tensile tension to the printed circuit board (200).

2. The circuit board detection clamping device as described in claim 1, characterized in that: It also includes a second clamping module pair (130). The first clamping module pair (120) is arranged along the first axis (D1), and the second clamping module pair (130) is arranged along the second axis (D2) which is perpendicular to the first axis (D1). The first clamping module pair (120) and the second clamping module pair (130) are used to perform biaxial stretching of the printed circuit board (200) along the first axis (D1) and the second axis (D2), and the first clamping module pair (120) and the second clamping module pair (130) can be operated sequentially to apply tensile tension to the printed circuit board (200) one after the other; The second clamping module pair (130) is connected to a second tension displacement module (136), which is used to drive the second clamping module pair (130) to move along the second axis (D2) to apply tensile tension to the printed circuit board (200).

3. The circuit board detection clamping device as described in claim 1, characterized in that: The first tension displacement module (126) includes a transmission belt (125) and a slide (127) disposed on the transmission belt (125). The lower support member (A) of the second clamping mechanism (124) and the upper clamping unit (B) are connected to the slide (127) to move synchronously with the slide (127).

4. The circuit board detection clamping device as described in claim 1, characterized in that: It also includes, A top rod (140) is vertically and flexibly disposed in the base opening (112) of the bearing base (110); The top rod (140) can be moved to be flush with the bearing surface of the lower support member (A) to assist in positioning the printed circuit board (200).

5. The circuit board inspection clamping device as described in claim 1, characterized in that: It also includes, A detection module (150), disposed on one side of the support base (110), is used to detect the printed circuit board (200); and The movable support module (160) is disposed at the base opening (112) of the bearing base (110) and includes at least one support crossbar (162). The support crossbar (162) is movable relative to the detection module (150) to switch between supporting the printed circuit board (200) and avoiding the detection path of the detection module (150).

6. An operation method for a circuit board inspection clamping device, characterized in that: Includes the following steps, A circuit board inspection clamping device is provided as described in any one of claims 1 to 5, wherein a printed circuit board (200) is supported on the support base (110), and the opposite two sides of the printed circuit board (200) correspond to the first clamping mechanism (122) and the second clamping mechanism (124), respectively. The printed circuit board (200) is placed on the lower support member (A), and the upper clamping unit (B) is driven to move relative to the lower support member (A) so as to clamp and fix the printed circuit board (200) together with the lower support member (A). The first tension displacement module (126) is activated, driving the second clamping mechanism (124) to move in a direction away from the first clamping mechanism (122), thereby applying tensile tension to the printed circuit board (200).

7. The operation method of the circuit board detection clamping device as described in claim 6, characterized in that: The circuit board detection clamping device further includes a second clamping module pair (130) arranged along the second axis (D2); The operation method further includes: After or simultaneously with the first clamping module pair (120) applying a first axial (D1) tensile tension to the printed circuit board (200), the second tension displacement module (136) is activated to drive the second clamping module pair (130) to move along the second axial (D2) and apply a second axial (D2) tensile tension to the printed circuit board (200) to achieve biaxial tension.

8. The operation method of the circuit board detection clamping device as described in claim 6, characterized in that: In the step of placing the printed circuit board (200) on the lower support member (A), the top rod (140) which is vertically and vertically disposed in the base opening (112) is first raised so that its top surface is flush with the support surface of the lower support member (A) to assist in positioning the printed circuit board (200). After clamping and securing the printed circuit board (200), the push rod (140) is lowered.

9. The operation method of the circuit board detection clamping device as described in claim 6, characterized in that: The printed circuit board (200) is inspected using a detection module (150) located on one side of the support base (110); During the testing process, the position of the support crossbar (162) of the active support module (160) is controlled so that it can be moved to provide support under the printed circuit board (200) when needed, and moved away to avoid the detection path of the detection module (150).

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