TWI556984B - Flexible interconnect circuit for using in printing cartridge - Google Patents

Description

Flexible circuit board for printing ink cartridges

The present invention relates to a flexible interconnect circuit, and more particularly to a flexible interconnect circuit suitable for printing ink cartridges.

With the development of technology and the growth of demand, the current printing and output devices, such as inkjet printers, can not only print a variety of documents and forms, but also provide the output of texts and digital photos, which become a daily life and work. An indispensable output device. In general, the inkjet printers use removable ink cartridges, so that when the ink cartridges stored in the ink cartridges are printed, the user can replace the inks used by the user.匣, and install a new print ink cartridge for inkjet printing. The inkjet printer and the inkjet printer are electrically interconnected so that the operation of printing the ink cartridge can be controlled by the inkjet printer.

The ink jet printer uses a printing ink cartridge as shown in Fig. 1. The ink cartridge 1 is composed of an upper cover 10, a cartridge 11, and an ink jet print head assembly 15, wherein the upper cover 10 is covered. Above the body 11, the ink jet print head assembly 15 is disposed below the body 11, and has a liquid storage space inside the body 11 for storing ink. The body 11 has a wall surface 12, and when the ink cartridge 1 is mounted on an ink jet printer (not shown), the wall surface 12 can be disposed corresponding to a socket (not shown). Flexible circuit on wall 12 A board 13 having a plurality of electrical contact points 14 thereon for electrical contact points on the flexible circuit board 13 through the ink jets 1 when the ink cartridge 1 is placed on the holder of the ink jet printer 14 is electrically connected to a guide (not shown) on the socket to control and/or monitor the electrical signal communication between the ink jet printer and the ink jet print head assembly 15 of the ink cartridge 1. .

However, if the ink jet 1 in the ink jet printer is incorrectly mounted, it may cause damage, for example, if the ink cartridge 1 is offset during installation, or the print is printed. The electrical circuit on the flexible circuit board 13 of the ink cartridge 1 has the problem of tolerance accuracy, or the printing ink cartridge 1 used in other inkjet printers is installed, and the electrical circuit thereof is incorrectly supplied. Energy, if it is severe, can result in damage to the inkjet printer 1, or the inkjet printer, or both, and the damage can cause loss to the user. Therefore, it is necessary to consider and avoid the above-mentioned improper operation of the printing ink cartridge 1 in the ink jet printer, and at the same time, by designing specific interconnecting circuits corresponding to each other, it is suitable for different ink jet printing. The printing ink cartridge 1 of the watch machine cannot be operated or failed after being installed on the machine, and can only be used with the ink cartridge 1 with its specific interconnection circuit, so as to avoid the installation in the inkjet printer. Incorrect printing of ink cartridges 1 caused damage to the inkjet printer 1 and the inkjet printer.

In view of this, how to develop a flexible interconnect circuit suitable for printing ink cartridges to improve the conventional installation of ink cartridges due to incorrect installation of ink cartridges, and the electrical circuit for printing ink cartridges cannot be correctly matched with inkjet printers. Corresponding connections, which in turn lead to the destruction of inkjet printers and inkjet printers, are urgently needed to be solved.

The purpose of this case is to provide a flexible interconnect circuit suitable for printing ink cartridges. The design of specific and corresponding flexible interconnect circuits solves the problem that the electrical circuit for printing ink cartridges cannot correctly correspond to the ink jet printer due to incorrect installation of the ink jets, thereby causing the columns Ink cartridges and inkjet printers are damaged.

In order to achieve the above object, a wider aspect of the present invention provides a flexible circuit board suitable for a column of ink cartridges having an origin hole and a flexible circuit board An interconnecting circuit, the flexible interconnecting circuit comprising: a plurality of conductive channels; a plurality of bonding pads electrically connected to one of the plurality of conductive channels; and an electrical contact point region configured with a plurality of columnar arrays Electrical contact points, wherein each of the electrical contact points is electrically connected to a corresponding one of the other ends of the conductive path, and the plurality of electrical contact points are configured to be disposed on one of the outer first group and the fourth group, a second group and a third group disposed on the inner side, having 3 rows of columns in the first group and the fourth group, and 2 rows in the second group and the third group a column wherein a center of the origin hole of the flexible circuit board is between the column direction (ie, the Y-axis direction) and the geometric center of the electrical contact point closest to the second column of the second group, most recently The straight line distance is at least less than 3 mm.

In order to achieve the above object, another broad aspect of the present invention provides a flexible circuit board suitable for a column of ink cartridges having an origin hole and a flexible plate disposed on the flexible circuit board. a flexible interconnection circuit comprising: a plurality of conduction channels; a plurality of coupling pads electrically connected to one of the plurality of conduction channels; and an electrical contact point region configured with a plurality of columnar arrays Arranging electrical contact points, wherein each of the electrical contact points is electrically connected to the other end of the corresponding conductive path such that each electrical contact point is electrically connected to the other end by the other end of the connected conductive path The number of electrical contacts is 40 for the bond pad.

1‧‧‧Printing ink

10‧‧‧Upper cover

11‧‧‧匣 Body

12‧‧‧ wall

13‧‧‧Circuit board

14‧‧‧Electrical contact points

15‧‧‧Inkjet print head assembly

2‧‧‧Flexible circuit board

20‧‧‧ origin hole

21‧‧‧Transmission channel

210‧‧‧One end of the conduction channel

211‧‧‧The other end of the conduction channel

22‧‧‧Connection gasket

23‧‧‧Electrical contact area

230, A11, A12, A13, A14, A15, A16, A21, A22, A23, A24, A25, A26, A31, A32, B11, B12, B13, B21, B22, B23, C11, C12, C13, D11, D12, D13, D14, D15, D16, C21, C22, C23 and D21, D22, D23, D24, D25, D26, D31, D32, label 1~42‧‧‧ electrical contact points

A‧‧‧First group

A1, B1, C1, D1‧‧‧ first column

A2, B2, C2, D2‧‧‧ second column

A3, D3‧‧‧ third column

P1, P2, P3, L1, L2‧‧‧ distance

Fig. 1 is a schematic view showing the ink jet of a general ink jet printer.

2 is a schematic structural view of a flexible circuit board according to a preferred embodiment of the present invention.

Fig. 3 is a schematic view showing the arrangement of electrical contact points of the flexible circuit board shown in Fig. 2, the electrical contact point area of the flexible interconnection circuit of the board.

Figure 4 is the electrical contact points shown in Figure 3, with the center of the origin of the flexible circuit board as the reference point, indicating the coordinate distribution of the geometric center of all electrical contact points.

Fig. 5 is a view showing another configuration of the flexible interconnection circuit of the flexible circuit board shown in Fig. 2.

Fig. 6 is a schematic view showing the electrical contact point arrangement of the flexible interconnection circuit of the flexible circuit board shown in Fig. 2.

Some exemplary embodiments embodying the features and advantages of the present invention are described in detail in the following description. It should be understood that the present invention is capable of various modifications in various embodiments and is not intended to limit the scope of the invention.

Please refer to FIG. 2, which is a schematic structural view of a flexible circuit board according to a preferred embodiment of the present invention. As shown, the flexible interconnect circuit 24 of the present invention is suitable for use in a row of ink cartridges (not shown). For example, the ink cartridge can be an ink cartridge 1 as shown in FIG. The flexible interconnect circuit 24 is disposed on the flexible printed circuit board 2 of the ink jet, and the flexible circuit board 2 has an origin hole 20. In some embodiments, the flexible circuit board 2 can be disposed on one of the rear wall surfaces (not shown) of the ink cartridge (not shown), or can be disposed on other wall surfaces, and the installation position can be Changes may be made depending on the actual application. And the scratch The interconnecting circuit 24 includes: a plurality of conductive channels 21, a plurality of bonding pads 22, and electrical contact regions 23, wherein the plurality of bonding pads 22 are electrically connected to one end 210 of the plurality of conductive channels 21, respectively, and the bonding pads 22 is also electrically connected to an inkjet printhead assembly (not shown); the electrical contact point region 23 is provided with a plurality of columnar arrays of electrical contact points 230, each of which has a corresponding conductive path The other end 211 of the 21 is electrically connected, that is, the conductive path 21 extends between the electrical contact point region 23 and the bonding pad 22 of the ink jet printhead assembly and provides an electrical connection therebetween. The electrical contact area 23 is used to provide an area for electrical connection to an ink jet print head assembly (not shown) that prints ink cartridges.

In some embodiments, the flexible circuit board 2 is formed of a flexible substrate, such as polyimine (PI) or other elastic polymer materials, but is not limited thereto. As for the flexible interconnection circuit 24 disposed on the flexible circuit board 2, as described above, the bonding pad 22 corresponding to the ink jet print head assembly (not shown), the conduction path 21, and the conduction path 21 are provided. It can be formed by corresponding electrical contact point regions 23, and the material thereof can be formed by copper, gold or any other conductive material, but is not limited thereto. Taking the embodiment as an example, the electrical contact point region 23 is a conductive region exposed by the opening in the flexible substrate, and in the conductive region, the plurality of electrical contact points 230 are in multiple rows of vertical and horizontal directions. Columnar arrays aligned with each other, the shape of the electrical contact points 230 may be, but are not limited to, a circle, an octagon, a square, a square with rounded squares or beveled corners, or some other shape, none of which This is limited.

In this embodiment, the number of the plurality of electrical contact points 230 in the electrical contact point region 23 is 42, but not limited thereto, and sometimes the electrical contact points are electrically connected to the plurality of bonding pads by the conduction path. The plurality of connection pads connected are not useful, and the number of electrical contacts is at least one or plural, so the number can be at least More than 40, sometimes the number of electrical contacts will be less than 40, depending on the design. And the plurality of electrical contact points 230 are configured to form a first group A and a fourth group D respectively disposed on the two outer sides, and a second group B and a third group C disposed on the inner side, wherein the first group The group A, the second group B, the third group C, and the fourth group D are based on the center 20 of the origin hole of the flexible circuit board 2, and are arranged symmetrically with their longitudinal center line C, in other words, That is, the number and arrangement of the plurality of electrical contact points 230 in the first group A are symmetrically arranged and corresponding to the number and arrangement of the plurality of electrical contact points 230 in the fourth group D, and the same The number and arrangement of the plurality of electrical contact points 230 in the second group B and the third group C disposed on the inner side are also symmetrically arranged and corresponding to each other.

In this embodiment, for example, there are three rows of columns A1, A2, and A3 in the first group A, wherein the first column A1, the second column A2, and the third column A3 are respectively from the outside to the inside, and The first column A1 and the second column A2 are each arranged with six electrical contacts A11, A12, A13, A14, A15, A16 and A21, A22, A23, A24, A25, A26, and the third column A3. Two electrical contact points A31 and A32 are arranged; similarly, the fourth group D disposed on the other opposite outer side also has three rows of columns D1, D2, and D3, and the first column is D1 and D1 from the outside to the inside. The two columns D2 and the third column D3, and the first column D1 and the second column D2 are also arranged with six electrical contact points D11, D12, D13, D14, D15, D16 and D21, D22, D23, D24, D25, D26, and the third column D3 are also provided with two electrical contact points D31 and D32.

The second group B disposed on the inner side has two rows of columns B1 and B2, and the first column B1 and the second column B2 are from the outside to the inside, and the second column B2 is adjacent to the flexible circuit board. 2, the origin hole 20 is arranged, and the first column B1 and the second column B2 are arranged with three electrical contact points B11, B12, B13 and B21, B22, B23, but the first column B1 and The electrical contact points B11, B12, B13 and B21, B22, B23 in the second column B2 are not aligned with each other, wherein the three electrical contact points B11, B12, B13 of the first column B1 are first and first. The electrical contact points A14, A15, A16 of the first column A1 in the group A are arranged in parallel with each other, and the three electrical contact points B21, B22, B23 of the second column B2 are spaced apart from each other, wherein The electrical contact point B21 is arranged in parallel with the electrical contact point A11 of the first column A1 in the first group A, and the second electrical contact point B22 is electrically connected to the first column A1 in the first group A. The contact points A13 are arranged in parallel, and the third electrical contact point B23 is arranged in parallel with the electrical contact point A15 of the first column A1 in the first group A. Similarly, the third group C disposed on the inner side is also provided with a first column C1 and a second column C2 from the outside, and the first column C1 and the second column C2 are also arranged with three electrical contacts. Points C11, C12, C13 and C21, C22, C23, and the electrical contact points C11, C12, C13 and C21, C22, C23 are arranged in the same way as the electrical contact points B11, B12, B13 of the second group B and B21, B22, and B23 are symmetrically arranged, and therefore will not be described again.

In another embodiment, the content includes Figures 3 and 4. Please refer to FIG. 3, which is a flexible interconnection circuit of the flexible circuit board shown in FIG. 2, and a schematic view of the electrical contact points in the electrical contact point area of the flexible interconnection circuit is shown.

As can be seen from FIG. 3, the flexible circuit board 2 has an origin hole 20, and the center of the origin hole 20 is used as a reference point, and its coordinates are (0, 0), and all 40 electrical contacts shown in FIG. 2 can be displayed. Point, re-displayed from 1 to 42, in order to facilitate the subsequent addition of the serial number in the middle, especially in the middle of the 29th and 30th, not marked in the third figure. These electrical contacts are all marked with a square graphic of the chamfer.

All 40 electrical contact points in this figure are in electrical contact with the embodiment of Figure 2 above. The dot arrangement positions are all identical, including the first group A having three rows of columns A1, A2, and A3, and the detailed numbers are A11 (label 2), A12 (label 6), A13 (label 10), and A14 (label) 14), A15 (reference numeral 18), A16 (number 24), A21 (number 4), A22 (number 8), A23 (number 12), A24 (number 16), A25 (number 20), A26 (number 26) 14, electrical contact points such as A31 (key 22) and A32 (key 28). The remaining second to fourth groups are the same, so they will not be described again.

Please refer to FIG. 4 again, which is a table column, which is the geometric center of each electrical contact point shown in FIG. 3, under the reference point of the center of the origin hole of the flexible circuit board, The distance, indicating the coordinate distribution of the geometric center of all electrical contact points; the direction of the coordinate is the X axis, and the center of the origin hole extends to the right to a positive value, and vice versa to a left value; The coordinates are in the Y-axis direction, extending from the origin to a positive value, and extending downward from the origin to a negative value.

Therefore, for example, the coordinates of the numeral 1 are (7.715, 10.045), and the coordinates of the numeral 2 are (-7.715, 10.045), so the distance between the two is 15.43 mm (mm) in the direction along the course. For another example, for example, the coordinates of the reference numeral 37 are (0.88, 2.045), so the distance from the center of the origin hole (0, 0), so the distance between the two is 0.88 mm (mm) along the course, along the column The direction distance is 2.045 mm (mm). The rest are all analogous.

Therefore, in the above embodiment, the center of the origin of the 40 electrical contact points and the origin hole 20 of the flexible circuit board is specifically used as a reference point, and the geometric centers of the X-axis and the Y-axis are clearly marked. An embodiment specifically discloses the relative positions of the geometric centers of all electrical contact points. However, other embodiments are not limited.

For another embodiment, please refer to FIG. 4 and FIG. 5 . The geometric center of all electrical contact points indicated in FIG. 4 is not only based on the center of the origin hole 20 of the flexible circuit board, but each of them. The coordinates of the geometric center of all electrical contact points are the same as the (x, y) coordinates of the previous embodiment, that is, as shown in Fig. 4, the present embodiment, as shown in Fig. 5, is also added to and decreased from the original coordinate to the X-axis. 0.68 mm (mm), that is, the new x coordinate range is (x-0.68 to x+0.68); the same is true for the Y axis, that is, the new y coordinate range is (y-0.68 to y+0.68), the unit All are in mm (mm).

Therefore, the geometric center coordinates of each electrical contact point in this embodiment are any points defined to fall within the area of a square, and the vertices of the square area are (x+0.68, y+0.68), (x -0.68, y+0.68), (x-0.68, y-0.68) and (x+0.68, y-0.68) consist of four points, so the geometric center coordinates of any electrical contact point fall within the area of the square Any of the points is covered by this embodiment.

Please refer to FIG. 6. FIG. 6 is a schematic diagram showing the configuration of the flexible interconnection circuit of the flexible circuit board shown in FIG. 2. As shown in the figure, the plurality of electrical contact points 230 of the electrical contact point region 23 of the flexible interconnection circuit 24 of the present embodiment are arranged as described above, and have the first group A and the first symmetrically disposed on the outer side. Four groups D, and second group B and third group C symmetrically disposed on the inner side. In the present embodiment, the electrical contact point A11 of the first column A1 of the first group A disposed outside and the electrical contact point A12 of the adjacent column A1 of the adjacent group A are disposed in the column direction (ie, Y) The linear distance P1 of the axial direction is at least less than 4 mm. In some embodiments, the closest linear distance P1 is preferably from 1.1 mm to 3.8 mm, but not limited thereto. And between the electrical contact point B21 of the second column B2 of the second group B disposed on the inner side and the electrical contact point B22 of the same column B2 adjacent thereto, in the column direction (ie, the Y-axis direction) Straight line distance It is at least less than 6 mm from the P2 system. In other embodiments, the most recent straight line distance P2 is preferably from 3 mm to 5.6 mm, and is not limited thereto. In addition, in the second column B2 of the second group B, the third electrical contact point B23 closest to the origin hole 21 and the origin hole 21 of the flexible circuit board 2 are in the column direction thereof. (ie, the Y-axis direction) the closest straight line distance P3 is at least less than 3 mm, and in other embodiments, the closest straight line distance P3 is preferably from 1.2 mm to 2.8 mm, and is not limited thereto. . Of course, since the fourth group D is symmetrically disposed with the first group A, in the fourth group D, the linear distance between the electrical contact points D11 and D12 of the first column D1 is also P1; The third group C and the second group B are symmetrically arranged, so in the third group C, the linear distance between the electrical contact point C21 of the second column C2 and the electrical contact point C22 is also P2, and the third The closest linear distance between the electrical contact point C23 and the origin hole 21 is also P3.

Referring to FIG. 6 , as shown in the figure, in the electrical contact point region 23, each electrical contact point A11, A12, A13, A14, A15 of the first column A1 of the first group A disposed outside is disposed. The linear distance L1 between the electrical contact points A21, A22, A23, A24, A25, and A26 of the second column A22 parallel to and adjacent to the A16, and the horizontal direction (ie, the X-axis direction) of the A16 is at least less than 3 In some embodiments, the most recent straight line distance L1 is from 0.8 mm to 2.8 mm, and as described above, the fourth group D is symmetrically disposed with the first group A. The distance between the electrical contact points D21, D22, D23, D24, D25, D26 of each electrical contact point D11, D12, D13, D14, D15, D16 in a column D1 and the second column D2 parallel thereto is also L1. And between the second electrical contact point B12 of the first column B1 of the second group B disposed on the inner side and the third electrical contact point B23 of the second column B2 adjacent thereto and adjacent to each other in the course direction The linear distance L2 (ie, the X-axis direction) is at least less than 3 mm, and in other embodiments, The optimum value of the nearest straight line distance L2 is 0.8 mm to 2.8 mm. Similarly, the third group C is also symmetrically arranged with the second group B, and therefore will not be described again.

In some embodiments, the plurality of electrical contact points B11, B12, B13, B23, C11, C12, C13, and C23 adjacent to the origin hole 21 in the second group B and the third group C disposed on the inner side are disposed. Arranging and constituting an array of "H" shapes, but not limited thereto, the array of "H" shapes is composed of 8 electrical contact points, and at the four vertex ends of the H-shape, the electrical contact points thereof The centerline to the centerline has a height of 4 mm and a width of 4.82 mm, but is not limited to this.

In summary, the design of the specific contact point of the electrical contact point in the flexible interconnect circuit of the present invention is correctly set corresponding to the corresponding inkjet printer, thereby avoiding Correct installation of the ink cartridges causes the electrical circuitry of the inkjet printer to fail to properly interface with the inkjet printer, which can result in damage to the inkjet printer and the inkjet printer.

The present invention has been described in detail by the above-described embodiments, and is intended to be modified by those skilled in the art.

2‧‧‧Flexible circuit board

20‧‧‧ origin hole

21‧‧‧Transmission channel

23‧‧‧Electrical contact area

230, A11, A12, A13, A14, A15, A16, A21, A22, A23, A24, A25, A26, A31, A32, B11, B12, B13, B21, B22, B23, C11, C12, C13, D11, D12, D13, D14, D15, D16, C21, C22, C23 and D21, D22, D23, D24, D25, D26, D31, D32, label 1~42‧‧‧ electrical contact points

A‧‧‧First group

A1, B1, C1, D1‧‧‧ first column

A2, B2, C2, D2‧‧‧ second column

A3, D3‧‧‧ third column

P1, P2, P3, L1, L2‧‧‧ distance

Claims (14)

A flexible circuit board suitable for a row of ink cartridges, the flexible circuit board having an origin hole, and the flexible circuit board is provided with a flexible interconnection circuit, the flexible interconnection circuit comprising: a plurality of conductive channels a plurality of bonding pads electrically connected to one end of the plurality of conductive channels; and an electrical contact point region configured with a plurality of electrical contacts of the columnar array arrangement, wherein each of the electrical contact points corresponds thereto The other end of the conductive channel is electrically connected, and the plurality of electrical contact points are configured to be disposed on one of the outer first group and the fourth group, the inner one of the second group, and a third group Having three rows of columns in the first group and the fourth group, and two rows of columns in the second group and the third group, wherein the origin hole of the flexible circuit board is centered on the vertical The shortest linear distance between the column direction (i.e., the Y-axis direction) and the geometric center of the electrical contact of the second column of the second group is less than 3 mm. The flexible circuit board of claim 1, wherein the origin of the flexible circuit board is centered in a column direction (ie, a Y-axis direction) and the second column of the second column of the electrical The shortest straight line distance between the geometric centers of the contact points is 1.2 mm to 2.8 mm. The flexible circuit board of claim 1, wherein the plurality of electrical contact points, each of the electrical contact points are electrically connected to the conductive path, and each of the electrical contact points is through the conductive channel Electrically connected to the plurality of bonding pads, The number of electrical contacts is 40. The flexible circuit board of claim 1, wherein the plurality of electrical contact points and the plurality of bonding pads are electrically connected to each of the electrical contacts by the conductive path The number of electrical contact points is at least one or plural. The flexible circuit board of claim 1, wherein the geometric center of the electrical contact point of the first column of one of the first groups disposed outside is adjacent to the same first column The linear distance between the geometric centers of the electrical contact points in the column direction (ie, the Y-axis direction) is less than 4 mm. The flexible circuit board of claim 5, wherein the geometric center of the electrical contact point of the first column of one of the first groups disposed outside is adjacent to the same first column The shortest linear distance between the geometric centers of the electrical contact points in the column direction (ie, the Y-axis direction) is from 1.1 mm to 3.8 mm. The flexible circuit board of claim 1, wherein the geometric center of the electrical contact point of the second column of the second group disposed on the inner side is adjacent to the same second column The geometric center of the electrical contact point, the shortest linear distance between the longitudinal direction (ie, the Y-axis direction) is less than 6 mm. The flexible circuit board of claim 7, wherein the geometric center of the electrical contact point of the second column of the second group disposed on the inner side is adjacent to the same second column The geometrical center of the electrical contact point, the shortest straight line distance between the longitudinal direction (ie, the Y-axis direction) is preferably from 3 mm to 5.6 mm. The flexible circuit board of claim 1, wherein the geometric center of the electrical contact point of the first column of one of the first groups disposed outside is parallel and adjacent to one of the second columns The closest linear distance between the geometric centers of the electrical contact points in the course direction (ie, the X-axis direction) is at least less than 3 mm. The flexible circuit board of claim 9, wherein the geometric center of the electrical contact point of one of the first columns of the first group disposed outside is parallel and adjacent to one of the second columns The closest linear distance between the geometric centers of the electrical contact points in the course direction (ie, the X-axis direction) is from 0.8 mm to 2.8 mm. The flexible circuit board of claim 1, wherein the second column of one of the second columns of the second group disposed on the inner side is parallel to and adjacent to the second column of the geometric center of the electrical contact point The shortest linear distance between the geometric centers of the electrical contact points in the course direction (ie, the X-axis direction) is at least less than 3 mm. The flexible circuit board of claim 11, wherein the geometrical center of the electrical contact point of the first column of one of the second groups disposed on the inner side is parallel to and adjacent to the second column The shortest linear distance between the geometric centers of the electrical contact points in the course direction (i.e., the X-axis direction) is from 0.8 mm to 2.8 mm. The flexible circuit board of claim 1, wherein the second group disposed on the inner side and the plurality of electrical contact points adjacent to the origin hole of the third group form an H-shaped array. The flexible circuit board of claim 13, wherein the array of H-shapes is composed of eight electrical contact points, and the center line to the center of the electrical contact point at the four vertex ends of the H-shape The line has a height of 4 mm and a width of 4.82 mm.