Smt tray detection assembly and parameter calculation method thereof

Abstract

The application provides an SMT tray detection assembly and a parameter calculation method thereof, which comprises a PCB circuit board, a transmitter, a receiver, an isolation blocking structure and a light absorption blocking structure on the opposite side. The PCB circuit board is provided with a plurality of tray detection ends, and a tray grid opening is arranged between every two adjacent tray detection ends. A matched pair of transmitter and receiver is arranged on each tray detection end. The transmitter and the receiver are arranged at the two ends of the same tray detection end at a preset installation included angle θ1, and the isolation blocking structure is arranged between the transmitter and the receiver of the same tray detection end. The light absorption blocking structure on the opposite side is arranged on one side of the installation surface of the tray detection end close to the transmitter and the receiver. The application can well avoid the problem of false triggering, is easy to design and implement, can be continuously used, and improves the actual effect and application range of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tray detection, in particular to an SMT tray detection assembly, and further relates to a parameter calculation method applied to the SMT tray detection assembly. BACKGROUND

[0002] In modern electronic device production management, in order to reduce error rate and improve production efficiency, various production enterprises generally use electronic racks to manage materials, and link with production management systems such as manufacturing execution system MES (Manufacturing Execution System) and warehouse management system WMS (Warehouse Management System) to realize data interaction, so as to realize accurate and efficient connection from technical data to production and manufacturing, and to realize advanced and first-out optimization of material management mode of material tray, so as to greatly reduce production and management cost. Among them, the SMT material management mode currently used includes two types of products, namely scanning code type and induction type, and SMT refers to Surface Mount Technology. Since the induction type SMT rack is more convenient to use and can be monitored in real time during operation, it has become the preferred technical solution of various enterprises. However, the traditional induction type SMT rack adopts a sampling method by means of reflection, and in actual production, the scheme realized by this reflection method may not be able to guarantee that the transmitted signal can be reflected or refracted on the surface of the tray and cannot pass through the observation window, thereby causing false detection of no material; it may also cause false triggering and continuous use due to the existence of high-transparency acrylic material in the tray. Therefore, the existing SMT tray detection scheme based on the reflection method obviously limits its actual use effect and application range due to the problems of easy false triggering and continuous use. SUMMARY

[0003] The technical problem to be solved by the present application is to provide an SMT tray detection assembly, which is based on a diffuse reflection method and an optimized structure design, can effectively avoid the problems of false triggering and continuous use, and improve the actual use effect and application range of the SMT tray detection assembly. On this basis, a parameter calculation method applied to the SMT tray detection assembly is also provided and applied.

[0004] To this end, the present application provides an SMT tray detection assembly, comprising: a PCB circuit board, a transmitter, a receiver, an isolation blocking structure and a cross-side light absorption blocking structure, a plurality of tray detection ends are arranged on the PCB circuit board, and a tray grid opening is arranged between every two adjacent tray detection ends; a matched pair of transmitter and receiver are arranged on each tray detection end, the transmitter and the receiver are arranged at two ends of the same tray detection end at a preset installation angle θ1, the preset installation angle θ1 refers to a preset angle between the installation surface of the transmitter or the receiver and the median line of the tray detection end, and the isolation blocking structure is arranged between the transmitter and the receiver of the same tray detection end; the cross-side light absorption blocking structure is arranged on one side of the tray detection end close to the installation surface of the transmitter and the receiver.

[0005] The detection process of the SMT tray detection assembly is as follows: the transmission light of the transmitter to the receiver of the same tray detection end is isolated and blocked by the isolation blocking structure; if the transmission light of the transmitter to the next tray detection end is absorbed by the corresponding cross-side light absorption blocking structure, the matched receiver cannot receive the transmission signal, at this time, it is judged that the state of the current tray grid opening is no tray; if the matched receiver successfully receives the transmission signal, it is judged that the state of the current tray grid opening is a tray.

[0006] Further improvement of the present application is that the length of the isolation blocking structure is greater than the first preset multiple of the projection length of the transmitter and the receiver in the horizontal direction, and the first preset multiple is greater than 1.

[0007] Further improvement of the present application is that the height of the isolation blocking structure is greater than the second preset multiple of the height of any one of the transmitter and the receiver, and the second preset multiple is greater than 1.

[0008] Further improvement of the present application is that the center points of the transmitter, the receiver and the isolation blocking structure are located on the same vertical line.

[0009] Further improvement of the present application is that the receiver is arranged at the bottom end of the tray detection end, and the transmitter is arranged at the top end of the tray detection end.

[0010] Further improvement of the present application is that the height of the cross-side light absorption blocking structure is consistent with the depth of the tray grid opening, and completely covers the installation surface of the transmitter and the receiver of the tray detection end.

[0011] Further improvement of the present application is that the isolation blocking structure adopts an isolation baffle, and the cross-side light absorption blocking structure adopts a cross-side light absorption plate.

[0012] A further improvement of the present invention is that the depth from the signal reflection point of the transmitter to the bottom of the material tray grid opening is greater than half of the center distance between the transmitter and the receiver.

[0013] The present invention also provides a parameter calculation method for an SMT tray detection component, which is applied to the SMT tray detection component described above and includes the following steps:

[0014] Step S1, calculate the maximum transmission distance L3 of the transmitter by the formula L3=L4-L7, and calculate the minimum transmission distance L8 of the transmitter by the formula L8=L4-L7', where L4 represents the width of the tray opening, L7 represents the thickness of the narrowest tray, and L7' represents the thickness of the widest tray;

[0015] Step S2, by formula (tanθ4)×L5 2 + 2×(L8-L3)×L5 +4×L3×L8×tanθ4= 0 to calculate the center distance L5 between the transmitter and the receiver, where θ4 refers to the half-attenuation angle of the transmitter;

[0016] Step S3: Calculate the angle θ3 using the formula tanθ3 = be / ce = L5 / (2×L3). The angle θ3 refers to the angle between the center of the transmitter lamp and the horizontal plane when the emission angle is equal to 0, at the strongest radiation position. be refers to the distance between the center point of the transmitter and the midpoint between the transmitter and the receiver. ce refers to the distance between the far-end reflection point and the midpoint between the transmitter and the receiver.

[0017] Step S4: using the angle θ3 as the preset installation angle θ1.

[0018] A further improvement of the present invention is that it also includes step S2'. After the center distance L5 is calculated in step S2, step S2' first determines whether L5 / 2 is less than the depth H3 from the signal reflection point of the transmitter to the bottom of the material tray grid opening. If so, it is determined that the current transmitter meets the requirements and jumps to step S3; if not, it is determined that the current transmitter does not meet the requirements, returns to reselect the transmitter, and jumps to step S2 to calculate the corresponding center distance L5 after the transmitter is reselected, until L5 / 2 is less than the depth H3 from the signal reflection point of the transmitter to the bottom of the material tray grid opening, then the parameter calculation and selection are completed, and jumps to step S3.

[0019] Compared with the prior art, the PCB circuit board is provided with a plurality of tray detection ends, and a tray grid is arranged between every two adjacent tray detection ends, so that independent detection of a plurality of trays can be realized at the same time; a matched pair of transmitter and receiver is arranged on each tray detection end, the transmitter and the receiver are arranged at two ends of the same tray detection end at a preset installation included angle θ1, and the isolation blocking structure is arranged between the transmitter and the receiver of the same tray detection end, so that sampling can be realized on the same side of the tray based on the diffuse reflection mode, and the transmission light of the transmitter is effectively avoided from being incorrectly received by the receiver to cause false triggering through the isolation blocking structure; on this basis, the opposite light absorption blocking structure for light absorption is arranged on one side of the tray detection end close to the installation surface of the transmitter and the receiver.

[0020] Therefore, in the state without the tray, the transmission light of the transmitter is blocked by the isolation blocking structure and is also absorbed by the opposite light absorption blocking structure, so that the receiver cannot receive the transmission signal, at this time, it can be quickly judged that the state of the tray grid is no tray; in the state with the tray, the transmission light of the transmitter is blocked by the isolation blocking structure, and the transmission signal close to the tray side will be received by the receiver, even if the tray exists a material such as acrylic with high transparency, the problem of false triggering no longer occurs, so that the detection of the tray can be accurately and quickly realized, the problem of false triggering is well avoided, and the SMT tray detection assembly is easy to design and realize, can be continuously used, and the practical use effect and the application range of the SMT tray detection assembly are effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of an embodiment of the present application;

[0022] Figure 2 is another structural schematic diagram of an embodiment of the present application;

[0023] Figure 3 is a structural schematic diagram of a tray of an embodiment of the present application;

[0024] Figure 4 is a structural schematic diagram of another tray of an embodiment of the present application;

[0025] Figure 5 is a structural schematic diagram of a PCB circuit board of an embodiment of the present application;

[0026] Figure 6 is a structural schematic diagram of an embodiment of the present application in a detection process;

[0027] Figure 7It is a schematic diagram of a local structure method of an embodiment of the present invention;

[0028] Figure 8 yes Figure 7 Schematic diagram of the enlarged structure of A in the middle;

[0029] Figure 9 yes Figure 7 Schematic diagram of the local structure in;

[0030] Figure 10 It is a simplified schematic diagram of an embodiment of the present invention;

[0031] Figure 11 This is a schematic diagram of the workflow of another embodiment of the present invention;

[0032] Figure 12 1 is a schematic diagram of an optimized workflow of step S2 according to another embodiment of the present invention.

[0033] Figure identification: 1-PCB circuit board; 101-tray detection end; 2-emitter; 201-first emitted light; 202-second emitted light; 3-receiver; 4-isolation blocking structure; 5-opposite side light absorption blocking structure; 6-tray opening; 7-tray; 701-tray detection surface; 702-material observation window; 703-material; 704-tray shaft. DETAILED DESCRIPTION

[0034] In the description of the present invention, if any directional description is involved, such as "upper", "lower", "front", "back", "left", "right", etc., the directions or positional relationships indicated are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limitations on the present invention. If a technical feature is referred to as being "disposed", "fixed", "connected", or "installed" on another technical feature, it can be directly disposed, fixed, or connected to the other technical feature, or it can be indirectly disposed, fixed, connected, or installed on the other technical feature.

[0035] In the description of the present invention, if "several" is used, it means more than one; if "plurality" is used, it means more than two; if "greater than," "less than," or "exceeds," it should be understood as excluding the number itself; if "above," "below," or "within" is used, it should be understood as including the number itself. If "first," "second," etc. is used, it should be understood that it is used only to distinguish the names of identical or similar technical features, and should not be understood to imply or indicate the relative importance of the technical features, the number of technical features, or the order of the technical features.

[0036] The preferred embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0037] Before introducing the specific embodiments of the present application, Figure 3 and Figure 4 The two commonly used trays shown are explained and illustrated. Figure 3 and Figure 4 In the diagram, the left side structure shows the front view of the tray 7, and the right side structure shows the side view of the tray 7. Figure 3 The material tray 7 shown has a material observation window 702, and Figure 4 The illustrated tray 7 lacks a material observation window. Material observation window 702 is a window structure used to estimate the remaining material quantity using the tray scale. In both types of trays 7, the tray detection surface 701 serves as the detection surface for the transmitter 2 and receiver 3, enabling detection by diffusely reflected light regardless of front or back. Material 703 refers to the material wrapped around the tray 7, and the tray shaft 704 is used to rotate the tray 7.

[0038] If the traditional through-beam method is used to implement SMT tray detection, since the through-beam method requires reflection or refraction on the surface of the tray 7 and enters the receiving end on the opposite side, the detection is then performed by judging the ratio of the received signal at the receiving end and the threshold. However, in actual applications, various factors may exist and it is impossible to guarantee that the transmitted signal can be reflected or refracted on the surface of the tray, which may easily lead to the signal not being able to pass through the material observation window 702, thereby causing the false detection of no material. In addition, if the tray 7 contains material 703 made of a highly transparent material such as acrylic, in this application scenario of the through-beam method, the transmitted signal changes very little. In this case, not only does a high-precision ADC module need to be used for sampling, but even if a high-precision ADC module is used, due to interference from ambient light, this signal with very little change needs to be judged and processed through a threshold. The setting of the threshold obviously has the problems of high precision, high difficulty and high cost, and will further increase the probability of false triggering, making the tray detection unable to be used continuously.

[0039] Unlike the existing technology, this application adopts diffuse reflection and optimized structural design, which avoids the processing of small signals in principle, because the signal required for reflection is as strong as possible. In the optimized structural design, in the state without a material tray, the transmitted signal has been blocked and absorbed, so there will be no false triggering phenomenon, and there is no need to accurately set the judgment threshold. The overall technical solution is more reasonable and efficient, easy to design and implement, and the continuous service life is greatly improved.

[0040] Specifically, such as Figures 1 to 12As shown, the embodiment provides an SMT tray detection assembly, which comprises a PCB circuit board 1, a transmitter 2, a receiver 3, an isolation blocking structure 4, and a light-absorbing blocking structure 5 on the opposite side. The PCB circuit board 1 is provided with a plurality of tray detection ends 101, and a tray grid opening 6 is arranged between every two adjacent tray detection ends 101. Each tray detection end 101 is provided with a matched pair of transmitter 2 and receiver 3. The transmitter 2 and the receiver 3 are arranged at both ends of the same tray detection end 101 at a preset installation angle θ1. The preset installation angle θ1 refers to the preset angle between the installation surface of the transmitter 2 or the receiver 3 and the median line of the tray detection end 101. The isolation blocking structure 4 is arranged between the transmitter 2 and the receiver 3 of the same tray detection end 101. The tray detection end 101 is provided with the light-absorbing blocking structure 5 on the opposite side. The light-absorbing blocking structure 5 is arranged on the side of the tray detection end 101 close to the installation surface of the transmitter 2 and the receiver 3. If the emitted light of the transmitter 2 is blocked by the isolation blocking structure 4 and absorbed by the light-absorbing blocking structure 5 on the opposite side, the receiver 3 cannot receive the emitted signal. At this time, it is judged that the current tray grid opening 6 is in the state of no tray 7. If the receiver 3 successfully receives the emitted signal, it is judged that the current tray grid opening 6 is in the state of having a tray 7. The installation surface refers to the installation structure of the bottom of the transmitter 2 and the receiver 3.

[0041] In the embodiment, the PCB circuit board 1 is the main control circuit board of the SMT tray detection assembly. The PCB circuit board 1 is provided with a plurality of tray detection ends 101 for realizing the diffuse reflection detection of the tray 7. The tray grid opening 6 is arranged between every two adjacent tray detection ends 101. The tray grid opening 6 refers to the window structure for placing the tray 7, which facilitates the independent detection of multiple trays 7 at the same time.

[0042] As Figure 1 , Figure 2 and Figures 6 to 8As shown, each tray detection end 101 of the embodiment is provided with a matched pair of transmitter 2 and receiver 3, the transmitter 2 and receiver 3 respectively refer to a diffuse reflection transmitter (a diffuse reflection device for emitting light) and a diffuse reflection receiver (a diffuse reflection device for receiving light); that is, the transmitter 2 and receiver 3 are matched and arranged in pairs, a pair of matched transmitter 2 and receiver 3 are arranged on the same side of the tray 7, and the sampling of the transmission signal is realized through the diffuse reflection transmission and reception process, the transmission signal refers to the signal of the emitted light. The transmitter 2 and receiver 3 are respectively arranged at both ends of the same tray detection end 101 with a preset installation angle θ1, the preset installation angle θ1 refers to the preset angle between the installation surface of the transmitter 2 or receiver 3 and the perpendicular of the tray detection end 101, which is preferably calculated by parameters such as the width of the tray grid hole 6, the thickness of the tray 7, and the half-angle θ4 of the transmitter 2 in actual application, or it can be obtained by looking up the table, see the description of the parameter calculation method of the SMT tray detection assembly below. And the isolation blocking structure 4 is arranged between the transmitter 2 and receiver 3 of the same tray detection end 101, which is preferably an isolation baffle, used to isolate and block the transmission of light, therefore, the embodiment can realize sampling based on the diffuse reflection method on the same side of the tray 7, and effectively avoid the false triggering caused by the error reception of the transmitter 2 by the receiver 3 through the isolation blocking structure 4.

[0043] It should be noted that the matched / paired transmitter 2 and receiver 3 of the embodiment adopts a diffuse reflection method, and is arranged on one tray detection end 101, that is, on the same side of the tray 7; while in the corresponding tray grid hole 6, the opposite side light blocking structure 5 is arranged on the other side of the tray 7. And the emission end (the end away from the installation surface) of the transmitter 2 is obliquely incident into the tray 7 at a preset installation angle θ1, so that the diffuse reflection phenomenon of the emitted light can occur on the tray detection surface 701, as shown in Figure 6 The light path of the second emitted light 202 defined in the above is shown, the second emitted light 202 refers to the received emitted light, even if there is a design of the material observation window 702 of the tray 7 or a transparent material 703, as long as part of the second emitted light 202 is successfully received by the receiver 3, it can accurately judge that the current state of the tray grid hole 6 is with the tray 7; therefore, the embodiment does not need to set a very accurate judgment threshold as in the prior art. Therefore, the embodiment can well avoid the problem of false triggering, and can be used continuously; in addition, due to the adoption of the optimized structure design, only it is needed to judge whether the transmission signal is received or not, the threshold setting range is wide, it is no longer necessary to set the threshold accurately and difficultly as in the prior art, the overall technical scheme is more reasonable, efficient and easy to implement.

[0044] In practical application, after part of the second emitted light 202 is successfully received by the receiver 3, the embodiment can preferably deliver to the master control unit MCU after a regular amplification process by an amplification comparison circuit (such as a multi-stage amplifier or other integrated circuits), of course, this process is a preferred implementation and does not belong to the essential features of the embodiment. The emitted light (also referred to as the detection light beam) of the emitter 2 described in the embodiment can be monochromatic light with a wavelength of 940 nm or 860 nm, and can also be other detectable wavelength light beams, as long as the wavelength of the light beam emitted by the emitter 2 matches the wavelength that can be received by the receiver 3.

[0045] On this basis, the tray detection end 101 side of the embodiment is also provided with a light absorption blocking structure 5 on the opposite side for light absorption. There is and only one side of each tray grid hole 6 is provided with the light absorption blocking structure 5 on the opposite side, which preferably adopts a light absorption plate on the opposite side, for realizing the absorption of emitted light when there is no tray 7 (no tray 7); the light absorption blocking structure 5 on the opposite side is arranged on the side of the tray detection end 101 close to the mounting surface of the emitter 2 and the receiver 3, so as to ensure that the emitted light of the previous tray detection end 101 is effectively absorbed when there is no tray 7, so as to avoid the problem that part of the emitted light is successfully received when there is no tray 7, effectively avoiding the disadvantages of false triggering, and reducing the difficulty and requirements for threshold setting.

[0046] As shown in Figure 6 and Figure 7 , the detection process of the SMT tray detection assembly of the embodiment is that the emitted light of the emitter 2 towards the receiver 3 of the same tray detection end 101 is isolated and blocked by the isolation blocking structure 4. In the state of no tray 7, the emitted light of the emitter 2 towards the next tray detection end 101 is absorbed by the light absorption blocking structure 5 (i.e. the corresponding light absorption blocking structure 5) arranged on the next tray detection end 101, at this time, the absorbed emitted light is represented as the first emitted light 201 in Figure 6 , and further makes the receiver 3 unable to receive the emitted signal corresponding to the first emitted light 201, so that the state of the current tray grid hole 6 can be quickly and accurately judged as no tray 7. In the state of having a tray 7, the emitted light of the emitter 2 towards the next tray detection end 101 is incident on the tray detection surface 701 of the tray 7, and is further received by the receiver 3 of the same tray detection end 101 through diffuse reflection, that is, the receiver 3 successfully receives the emitted signal, and judges that the state of the current tray grid hole 6 is having a tray 7; at this time, the received emitted light is represented as the second emitted light 202 in Figure 6The second emitted light 202 is represented in the middle. Since the embodiment adopts a diffuse reflection receiving on the same side of the tray 7, even if the tray 7 has a high-transparency material such as acrylic or the like, the problem of false triggering no longer occurs, and the detection of the tray 7 can be accurately and quickly realized, the problem of false triggering is well avoided, the SMT tray detection assembly can be continuously used, and the practical use effect and the application range of the SMT tray detection assembly are effectively improved.

[0047] In Figures 6 to 10 , the definitions of various parameters are as follows: L1 is the length of the isolation blocking structure 4; L2 is the length (also referred to as the width) of the opposite light-absorbing blocking structure 5; L3 is the designed farthest reflection distance, i.e., the farthest emission distance of the emitter 2; L4 is the width of the tray grid hole 6; L5 is the center distance between the emitter 2 and the receiver 3; L6 is the projection length of the emitter 2 and the receiver 3 in the horizontal plane; L7 is the thinnest tray thickness; L7' is the thickest tray thickness; L8 is the designed nearest reflection distance, i.e., the nearest emission distance of the emitter 2; H1 is the height of the isolation blocking structure 4; H2 is the height of the opposite light-absorbing blocking structure 5, which is also used to represent the depth of the tray grid hole 6; H3 is the depth from the reflection point of the center emission signal to the bottom of the tray grid hole 6, i.e., the depth from the reflection point of the signal of the emitter 2 to the bottom of the tray grid hole 6; θ1 is the preset installation angle between the emitter 2 and the receiver 3 and the vertical line; θ2 and θ5 are auxiliary angles; θ3 is the angle between the central emission signal of the lamp bead and the horizontal plane when the emission angle of the strongest radiation position is equal to 0, i.e., the angle between the central emission signal of the lamp bead of the emitter 2 and the horizontal plane when the emission angle of the strongest radiation position is equal to 0; θ4 is the half-decline angle, which can be obtained from the factory data of the emitter 2 and is used to represent the half-decline angle parameter of the angle between the central light intensity and the 1 / 2 light intensity line of the emitter 2; a is the center point of the receiver 3, b is the center point of the emitter 2, c is the far-end reflection point, d is the near-end reflection point, and e is the intersection point of the auxiliary line passing through the points d and c and the vertical line passing through the points a and b. Since the far-end reflection point c and the near-end reflection point d are both H3 away from the deepest edge of the tray grid hole 6, ce is perpendicular to ab, θ3 is equal to θ3', θ3' is an auxiliary angle, and θ5=θ3'+θ4=θ3+θ4.

[0048] Likewise, it is worth mentioning that, as Figure 7 and Figure 8As shown, preferably, the length L1 of the isolation blocking structure 4 is greater than a first preset multiple of the projection length L6 of the transmitter 2 and the receiver 3 in the horizontal direction, and the first preset multiple is greater than 1. The first preset multiple refers to a preset multiple threshold, which can be set and adjusted according to actual conditions and requirements. In the embodiment, the first preset multiple is 1.2 by default, so that the transmitter 2 in the same tray detection end 101 can completely isolate and block the transmission light from the receiver 3 in the horizontal direction, so as to avoid the possibility of false triggering. The height H1 of the isolation blocking structure 4 is greater than a second preset multiple of the height of any one of the transmitter 2 and the receiver 3, and the second preset multiple is greater than 1. The height H1 of the isolation blocking structure 4 is related to the height of the components of the transmitter 2 and the receiver 3. The second preset multiple refers to another preset multiple threshold, which can be set and adjusted according to actual conditions and requirements. In the embodiment, the second preset multiple is also 1.2 by default, so that the transmitter 2 and the receiver 3 can be completely isolated and blocked in the vertical direction, so as to further avoid the possibility of false triggering.

[0049] In actual production, the isolation and blocking effect between the transmitter 2 and the receiver 3 in the same tray detection end 101 need to be ensured in the horizontal and vertical directions. In addition to the length and height dimensions, the installation position also has an effect. Therefore, the center points of the transmitter 2, the receiver 3 and the isolation blocking structure 4 are located on the same vertical line, as shown in Figures 7 to 8 so as to not only ensure the isolation and blocking effect, but also be more conducive to the processing and production of products and improve the production yield of products.

[0050] In the embodiment, the transmitter 2 and the receiver 3 need to be set in the same tray detection end 101. The receiver 3 can be set at the bottom end of the tray detection end 101, and the transmitter 2 can be set at the top end of the tray detection end 101, as shown in Figure 2 The receiver 3 can be set at the top end of the tray detection end 101, and the transmitter 2 can be set at the bottom end of the tray detection end 101, as shown in Figure 1 The above two actual setting modes can be selected according to application requirements or scenes. Since the receiver 3 is more susceptible to sunlight, preferably, as shown in Figure 2As shown, the receiver 3 is arranged at the bottom end of the tray detection end 101, and the transmitter 2 is arranged at the top end of the tray detection end 101. If the receiver 3 is arranged at the top end of the tray detection end 101, the design requirements will be higher, and therefore, in order to meet various application requirements and improve the application range of the product, in other drawings of the embodiment, the transmitter 2 is preferably arranged at the bottom end of the tray detection end 101, and the receiver 3 is arranged at the top end of the tray detection end 101.

[0051] The height H2 of the opposite light absorption blocking structure 5 in the embodiment is related to the mounting structure, that is, related to the depth of the tray grid hole 6, and needs to ensure that the height completely blocks the structure assembly behind, so that the first emitted light 201 cannot be reflected by other structure components and be received by any receiver 3 when there is no tray 7, so as to avoid false triggering. Therefore, preferably, the height H2 of the opposite light absorption blocking structure 5 in the embodiment is consistent with the depth of the tray grid hole 6, and completely blocks the mounting surface of the transmitter 2 and the receiver 3 of the tray detection end 101.

[0052] It should be noted that, as Figure 10 As shown, the depth H3 from the signal reflection point of the transmitter 2 to the bottom of the tray grid hole 6 is greater than half of the center distance L5 between the transmitter 2 and the receiver 3. The signal reflection point of the transmitter 2 includes a distal reflection point c and a proximal reflection point d. In the embodiment, the depth H3 from the signal reflection point to the bottom of the tray grid hole 6 needs to be greater than half of the center distance L5 between the transmitter 2 and the receiver 3, so as to meet the actual installation requirements of the transmitter 2 and avoid design errors.

[0053] On the basis of providing the SMT tray detection assembly, another technical problem to be solved by the embodiment is how to calculate the preset installation angle θ1 between the transmitter 2 and the receiver 3 and the vertical line according to known parameters, and calculate the center distance L5 between the transmitter 2 and the receiver 3, so as to provide a parameter basis for the production of the SMT tray detection assembly, facilitate the design and production of products meeting the requirements, and ensure the yield of the products. The known parameters include the width L4 of the tray grid hole 6, the thickness L7 of the thinnest tray 7 and the thickness L7' of the widest tray, and the half-angle θ4 of the transmitter 2.

[0054] As shown in the drawings, Figure 11 The embodiment also provides a parameter calculation method of an SMT tray detection assembly, which is applied to the SMT tray detection assembly and includes the following steps:

[0055] Step S1, calculate the farthest transmission distance L3 of the transmitter 2 by the formula L3=L4-L7, and calculate the closest transmission distance L8 of the transmitter 2 by the formula L8=L4-L7', where L4 represents the width of the tray opening 6, L7 represents the thickness of the narrowest tray 7, and L7' represents the thickness of the widest tray 7;

[0056] Step S2, by the formula (tanθ4) × L5 2 + 2×(L8-L3) ×L5 +4×L3×L8×tanθ4= 0 to calculate the center distance L5 between transmitter 2 and receiver 3, where θ4 refers to the half-attenuation angle of transmitter 2;

[0057] Step S3: Calculate the angle θ3 using the formula tanθ3 = be / ce = L5 / (2×L3). The angle θ3 refers to the angle between the center of the transmitter 2 lamp bead and the horizontal plane when the emission angle is equal to 0, at the strongest radiation position. be refers to the distance between the center point of the transmitter 2 and the midpoint between the transmitter 2 and the receiver 3. ce refers to the distance between the far-end reflection point and the midpoint between the transmitter 2 and the receiver 3.

[0058] Step S4: using the angle θ3 as the preset installation angle θ1.

[0059] In this embodiment, if Figure 10 As shown, θ1+θ2 is the 90° angle between the vertical line and the horizontal plane, that is, 90°=θ1+θ2. θ2+θ3 is the 90° angle between the center signal line of transmitter 2 and the mounting surface of transmitter 2, that is, 90°=θ2+θ3. Therefore, θ1=θ3=θ3'. Therefore, we only need to calculate the angle between the center transmitted signal line of transmitter 2 and the horizontal plane, which is the preset installation angle θ1, also known as the lamp bead mounting angle.

[0060] In order to ensure the detection stability of the material tray 7, this embodiment also needs to consider a certain margin. The depth H3 from the signal reflection point of the transmitter 2 to the bottom of the material tray opening 6 is selected by default as half of the height H0 between the bottom of the material observation window 702 and the bottom of the material tray 7, that is, the default value H3=H0 / 2, to ensure that even if the material tray 7 is provided with a material observation window 702, the reflection path of the central light path will not be affected by the position of the material tray 7.

[0061] like Figure 10 As shown, the length of ce is equal to L3, the length of de is equal to L8, and the length of be is equal to L5 / 2. That is, tanθ3' = be / ce = L5 / (2×L3), and tanθ5 = be / de = L5 / (2×L8).

[0062] Since θ5 = θ3 + θ4 = θ3' + θ4, it is substituted into the formula tanθ5 = be / de = L5 / (2×L8), so that tan(θ3' + θ4) = L5 / (2×L8) can be obtained. According to the tangent formula tan(θ3' + θ4) = (tanθ3' + tanθ4) / (1 - tanθ3' tanθ4), the formula tanθ3' = be / ce = L5 / (2×L3) is substituted into the formula tan(θ3' + θ4) = (tanθ3' + tanθ4) / (1 - tanθ3' tanθ4), so that (L5 / (2×L3) + tanθ4) / (1 - L5 / (2×L3) tanθ4) = L5 / (2×L8) can be obtained. After simplifying this formula, (tanθ4) × L5 2 + 2×(L8-L3)×L5 +4×L3×L8×tanθ4= 0 can be obtained.

[0063] Therefore, according to the known width L4 of the tray grid hole 6, the thickness L7 of the narrowest tray 7, the thickness L7' of the widest tray, and the half-angle θ4 of the transmitter 2, the center distance L5 between the transmitter 2 and the receiver 3 is first calculated by the general solution of the quadratic equation, and then the included angle θ3 is calculated by the formula tanθ3 = tanθ3' = be / ce = L5 / (2×L3), and the included angle θ3 is used as the preset installation included angle θ1.

[0064] It should be noted that, as Figure 12 indicated, the embodiment further preferably includes a step S2' of judging whether L5 / 2 is less than the depth H3 of the signal reflection point of the transmitter 2 to the bottom of the tray grid hole 6 after calculating the center distance L5 in step S2. If yes, it is determined that the current transmitter 2 meets the requirements, and jumps to step S3. If not, it is determined that the current transmitter 2 does not meet the requirements, and returns to reselecting the transmitter 2, and jumps to step S2 to calculate the corresponding center distance L5 after reselecting the transmitter 2, until L5 / 2 is less than the depth H3 of the signal reflection point of the transmitter 2 to the bottom of the tray grid hole 6, then the calculation and selection of parameters are completed, and jumps to step S3. The parameters include the center distance L5 between the transmitter 2 and the receiver 3, and the preset installation included angle θ1, so as to accurately find the matching and production-demand-meeting diffuse reflection component, and ensure the production yield of the product.

[0065] Of course, in actual application, the embodiment can also be pre-calculated according to the width L4 of the commonly used tray grid hole 6, the thickness L7 of the narrowest tray 7, the thickness L7' of the widest tray, and the half angle θ4 of the transmitter 2, to obtain the corresponding center distance L5 of the transmitter 2 and the receiver 3, and the preset installation angle θ1, and to establish an index table with a corresponding relationship, and then in actual production, by querying the index table through the known parameters such as the width of the tray grid hole 6, the thickness of the tray 7 (including the thickness L7 of the narrowest tray 7 and the thickness L7' of the widest tray), and the half angle θ4 of the transmitter 2, the corresponding center distance L5 and the preset installation angle θ1 are quickly obtained, so as to improve the production efficiency of the product.

[0066] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can also be made, which should be considered as belonging to the protection scope of the present application.

Claims

1. An SMT tray detection assembly, characterized by, The SMT tray detection assembly comprises a PCB, a transmitter, a receiver, an isolation blocking structure, and a light-absorbing blocking structure on the opposite side, a plurality of tray detection ends are arranged on the PCB, and a tray grid opening is arranged between every two adjacent tray detection ends; a pair of transmitters and receivers matched with each other are arranged on each tray detection end, the transmitter and the receiver are arranged at two ends of the same tray detection end at a preset installation angle θ1, the preset installation angle θ1 refers to a preset angle between the installation surface of the transmitter or the receiver and the median line of the tray detection end, and the isolation blocking structure is arranged between the transmitter and the receiver of the same tray detection end; the light-absorbing blocking structure on the opposite side is arranged on one side of the tray detection end close to the installation surface of the transmitter and the receiver. In the detection process of the SMT tray detection assembly, the transmitter emits light to the receiver of the same tray detection end, and the isolation blocking structure is used for isolation and blocking. If the transmitter emits light to the next tray detection end, and the light is absorbed by the corresponding light-absorbing blocking structure on the opposite side, the matched receiver cannot receive the transmission signal, and at this time, it is determined that the current tray grid opening is empty. If the matched receiver successfully receives the transmission signal, it is determined that the current tray grid opening is full. The parameter calculation method of the SMT tray detection assembly comprises the following steps: Step S1, the farthest transmission distance L3 of the transmitter is calculated by the formula L3=L4-L7, and the nearest transmission distance L8 of the transmitter is calculated by the formula L8=L4-L7', wherein L4 represents the width of the tray grid opening, L7 represents the thickness of the thinnest tray, and L7' represents the thickness of the widest tray; Step S3, the angle θ3 is calculated by the formula tanθ3=be / ce=L5 / (2×L3), wherein the angle θ3 refers to the angle between the central transmission signal of the transmitter lamp bead and the horizontal plane when the strongest radiation position exit angle is equal to 0, be represents the distance between the center point of the transmitter and the midpoint between the transmitter and the receiver, and ce represents the distance between the far-end reflection point and the midpoint between the transmitter and the receiver; Step S2, the center distance L5 between the transmitter and the receiver is calculated by the formula (tanθ4) x L5 2 + 2 x (L8-L3) x L5 + 4 x L3 x L8 x tanθ4 = 0, where θ4 refers to the half angle of the transmitter; Step S4, the angle θ3 is used as the preset installation angle θ1. The length of the isolation blocking structure is greater than the first preset multiple of the projection length of the transmitter and the receiver in the horizontal direction, and the first preset multiple is greater than 1.

2. The SMT tray detection assembly of claim 1, wherein, The height of the isolation blocking structure is greater than the second preset multiple of the height of any one of the transmitter and the receiver, and the second preset multiple is greater than 1.

3. The SMT tray detection assembly of claim 2, wherein, The center points of the transmitter, the receiver, and the isolation blocking structure are located on the same vertical line.

4. The SMT tray detection assembly of claim 2, wherein, The receiver is arranged at the bottom end of the tray detection end, and the transmitter is arranged at the top end of the tray detection end.

5. The SMT tray detection assembly according to any one of claims 1 to 4, characterized in that The height of the light-absorbing blocking structure on the opposite side is consistent with the depth of the tray grid opening, and completely covers the installation surface of the transmitter and the receiver of the tray detection end.

6. The SMT tray detection assembly according to any one of claims 1 to 4, characterized in that The isolation blocking structure adopts an isolation baffle, and the light-absorbing blocking structure on the opposite side adopts a light-absorbing plate.

7. The SMT tray detection assembly according to any one of claims 1 to 4, characterized in that ​ 8. The SMT tray detection assembly according to any one of claims 1 to 4, characterized in that The depth from the signal reflection point of the transmitter to the bottom of the tray grid hole is greater than half of the center distance between the transmitter and the receiver.

9. The SMT tray detection assembly according to any one of claims 1 to 4, characterized in that The parameter calculation method of the SMT tray detection assembly further includes a step S2', which is performed after the center distance L5 is calculated in step S2. First, it is determined whether L5 / 2 is less than the depth H3 from the signal reflection point of the transmitter to the bottom of the tray grid hole. If yes, it is determined that the current transmitter meets the requirements, and the process jumps to step S3. If no, it is determined that the current transmitter does not meet the requirements, and the process returns to the re-selection of the transmitter. Then, the calculation of the corresponding center distance L5 after the re-selection of the transmitter is performed, until L5 / 2 is less than the depth H3 from the signal reflection point of the transmitter to the bottom of the tray grid hole. Then, the calculation and selection of the parameters are completed, and the process jumps to step S3.

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