Laser measurement method and laser measurement device

Abstract

The present invention pertains to a laser measurement method that is a height measurement method for measuring the height of a plurality of pins (3) by radiating laser light onto a to-be-measured object (1A), which has the plurality of pins (3) standing upright from one surface of a base material (2) and in which the plurality of pins (3) are respectively arranged with gaps therebetween in a first direction (D1) and a second direction (D2) that intersect each other within the plane of the base material (2), and measuring the laser light that is reflected by and returns from the to-be-measured object (1A) while the laser light is scanned within the plane of the base material (2). The height of the plurality of pins (3) is measured while scanning the laser light in a third direction (D3) in which the gap between two of the pins (3), from among four of the pins (3) adjacent to each other in the first direction (D1) and the second direction (D2), is greater than the gap in the first direction D1 and the gap in the second direction (D2).

Description

Laser measurement method and laser measurement device

[0001] The present invention relates to a laser measurement method and a laser measurement device. This application claims priority to Japanese Patent Application No. 2023-139706, filed on August 30, 2023, the contents of which are incorporated herein by reference.

[0002] The heat sink has pin-shaped (columnar) fins (so-called pin fins) that stand up from one side of a plate-shaped base material (substrate), and these multiple pin fins are arranged in a staggered or lattice pattern with spaces between each other in directions that intersect with each other within the surface of the substrate.

[0003] In heat sinks with such pin fins, the heights of the pin fins are measured using a laser measuring device (see, for example, Patent Document 1 listed below).

[0004] Specifically, the height of multiple pin fins is measured by irradiating a heat sink, which is the object to be measured, with laser light, scanning the laser light across the surface of the substrate, and measuring the laser light that is reflected back from the heat sink.

[0005] JP 2013-102053 A

[0006] However, with the conventional laser measurement method described above, when measuring the height from the base of the pin fin, the spot of laser light irradiated between the pin fins can interfere with adjacent pin fins, making it difficult to accurately measure the height of multiple pin fins.

[0007] On the other hand, if the spot diameter of the laser light is reduced to avoid interference of the laser light between adjacent pin fins, the tolerance for misalignment of the laser light with respect to the pin fins when scanning with the laser light will decrease.

[0008] In particular, the narrower the spacing between adjacent pin fins, the more laser light with a spot diameter smaller than the spacing must be emitted to avoid interference between the pin fins, which reduces the tolerance for positional deviation of the laser light.

[0009] The present invention has been proposed in view of the above-described conventional circumstances, and has an object to provide a laser measurement method and laser measurement device that can increase the tolerance for positional deviation of laser light while avoiding interference of laser light.

[0010] To achieve the above object, one aspect of the present invention has the following means. [1] A laser measurement method for measuring heights of a measurement object having a plurality of pins standing from one surface of a base material, the plurality of pins being arranged at intervals in a first direction and a second direction intersecting each other within the surface of the base material, by irradiating a laser beam onto the measurement object and measuring the laser beam reflected and returning from the measurement object while scanning the laser beam within the surface of the base material, the method comprising: measuring the heights of the plurality of pins while scanning the laser beam in a third direction in which the interval between two adjacent pins among four pins adjacent to each other in the first direction and the second direction is larger than the interval in the first direction and the interval in the second direction; [2] The laser measurement method described in [1], characterized in that the laser beam is irradiated onto the measurement object while being focused; [3] The laser measurement method described in [2], characterized in that the spot diameter of the laser beam is set smaller than the gaps formed between three adjacent pins among the four pins. [4] The laser measurement method according to [1], characterized in that the plurality of pins are arranged in a staggered pattern within the surface of the base material. [5] The laser measurement method according to [1], characterized in that the plurality of pins are arranged in a lattice pattern within the surface of the base material. [6] The laser measurement method according to [1], characterized in that the object to be measured is a heat sink.[7] A laser measurement device that irradiates a laser beam onto an object to be measured, the object having a plurality of pins standing up from one surface of a base material, the plurality of pins being arranged at intervals in a first direction and a second direction that intersect with each other within the surface of the base material, and measures the height of the plurality of pins by measuring the laser beam reflected and returning from the object to be measured while scanning the laser beam within the surface of the base material, the laser measurement device comprising: an optical unit that irradiates the object to be measured with the laser beam; a scanning unit that scans the laser beam within the surface of the base material; a light-receiving unit that receives the laser beam reflected and returning from the object to be measured; and a calculation unit that calculates and measures the height of the plurality of pins based on the measurement results of the laser beam received by the light-receiving unit, wherein the scanning unit scans the laser beam in a third direction in which the interval between two adjacent pins, out of four pins that are adjacent to each other in the first direction and the second direction, is larger than the interval in the first direction and the interval in the second direction. [8] The laser measurement device according to [7], wherein the optical unit irradiates the laser light onto the object to be measured while concentrating the laser light. [9] The laser measurement device according to [8], wherein the optical unit makes the spot diameter of the laser light smaller than the gaps formed between three adjacent pins out of the four pins.

[0011] As described above, the present invention provides a laser measurement method and laser measurement device that can increase the tolerance for laser positional deviation while avoiding interference of laser light.

[0012] FIG. 1 is a plan view of a heat sink for explaining a laser measurement method according to a first embodiment of the present invention. FIG. 2 is a side view of the heat sink shown in FIG. 1. FIG. 3 is a plan view showing the dimensions of each portion of adjacent pin fins of the heat sink shown in FIG. 1. FIG. 4 is a schematic view showing the configuration of a laser measurement device. FIG. 5 is a side view showing a state in which laser light is irradiated onto the heat sink shown in FIG. 1 or 6. FIG. 6 is a plan view for explaining the spot diameter of laser light irradiated onto the heat sink shown in FIG. 1. FIG. 7 is a plan view of a heat sink for explaining a laser measurement method according to a second embodiment of the present invention. FIG. 8 is a graph showing the results of measuring the heights of multiple pin fins of a heat sink using the laser measurement method of an example. FIG. 9 is a graph showing the results of measuring the heights of multiple pin fins of a heat sink using the laser measurement method of a comparative example.

[0013] An embodiment of the present invention will be described in detail below with reference to the drawings. The drawings used in the following description may show characteristic portions enlarged for ease of understanding, and the dimensional ratios of the components may not be the same as those in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not necessarily limited to them. Appropriate modifications may be made within the scope of the present invention.

[0014] First Embodiment First, as a first embodiment of the present invention, a laser measurement method (height measurement method) and a laser measurement device 100 shown in explanatory diagrams in, for example, FIGS. 1 to 6 will be described.

[0015] FIG. 1 is a plan view of a heat sink 1A for explaining the laser measurement method according to the first embodiment. FIG. 2 is a side view of the heat sink 1A. FIG. 3 is a plan view showing the dimensions of each portion of adjacent pin fins 3 of the heat sink 1A. FIG. 4 is a schematic diagram showing the configuration of a laser measurement device 100. FIG. 5 is a side view showing a state in which laser light L is irradiated onto the heat sink 1A. FIG. 6 is a plan view for explaining the spot diameter of the laser light L irradiated onto the heat sink 1A.

[0016] (Heat sink) The heat sink 1A, which is the object to be measured in this embodiment, comprises a plate-shaped base material (hereinafter referred to as "substrate") 2 and a plurality of pin-shaped (columnar) fins (hereinafter referred to as "pin fins") 3 standing upright from one surface of the substrate 2, as shown in Figures 1 and 2.

[0017] The heat sink 1A can be made of, for example, aluminum, aluminum alloy, copper, copper alloy, iron, or iron alloy. Alternatively, the heat sink 1A can be made of a clad material (composite material) made by bonding two or more metals together. However, the material of the heat sink 1A is not limited to these metals or alloys, and various metal materials commonly used for the heat sink 1A can be used. The heat sink 1B, which will be described later, can also be made of the same material as the heat sink 1A.

[0018] The heat sink 1A has a structure in which a plurality of pin fins 3 are arranged in a staggered pattern with intervals provided in a first direction D1 and a second direction D2 that intersect with each other within the plane of the substrate 2. In other words, the pin fins are arranged so that the nearest neighbors are not aligned in orthogonal directions (e.g., vertical and horizontal) within the plane of the substrate 2, but are alternately shifted.

[0019] The shape of the pin fins 3 is not particularly limited, and examples thereof include a circular shape, an elliptical shape, a rectangular shape such as a square or a diamond shape in a plan view.

[0020] The heat sink 1A has cylindrical pin fins 3 each having the same diameter and height, arranged in a staggered pattern at equal intervals in both the first direction D1 and the second direction D2.

[0021] In this embodiment, as shown in Fig. 3, the third direction D3 is the direction in which the distance between two adjacent pin fins 3 among four pin fins 3 adjacent to each other in the first direction D1 and the second direction D2 is larger than the distance in the first direction D1 and the distance in the second direction D2. That is, the heat sink 1A shown in Fig. 3 is shown with the distance between two pin fins 3 in the third direction D3 larger than the distance between two pin fins 3 in the first direction D1 and the distance between two pin fins 3 in the second direction D2.

[0022] 2 and 3, the center-to-center spacing in the first direction D1 and the center-to-center spacing in the second direction D2 are designated "d", and the height of the pin fins 3 is designated "h". In the field of heat sinks, many pin fins with a height (h) of about 3d to 4d are commercially available.

[0023] Of the four pins that are adjacent to each other in the first direction D1 and the second direction D2, the distance between two adjacent pins is defined as "s". In the heat sink 1A shown in a plan view in FIG. 3, the distance between the first direction D1 and the second direction D2 is (s-d) in terms of the inner distance. The distance between the third direction D3 is (3 １／２ s), and the inner interval is {(3 １／２ Therefore, the spacing in the third direction D3 is greater than the spacing in the first direction D1 and the spacing in the second direction D2, that is, (s−d).

[0024] The above dimensions are merely examples and are not necessarily limited to these dimensions. The dimensions of each part can be changed as appropriate depending on, for example, the tongue ratio.

[0025] 4 , the laser measurement device 100 of this embodiment includes an optical unit 101 that irradiates one surface of the substrate 2 of the heat sink 1A, which is the object to be measured, with laser light L, a scanning unit 102 that scans the laser light L within the surface of the substrate 2, a light receiving unit 103 that receives the laser light L reflected back from the one surface of the substrate 2 of the heat sink 1A, and a calculation unit 104 that measures the heights of the multiple pin fins 3 by calculation based on the measurement results of the laser light L received by the light receiving unit 103, and these are arranged inside the device main body 105. The laser light L is irradiated onto the surface of the substrate 2 on which the pin fins 3 are provided.

[0026] The optical unit 101 includes a light source 1011 such as a semiconductor laser and a focusing optical system 1022 such as a lens that focuses the laser light L emitted from the light source, and irradiates the laser light L onto one surface of the substrate 2 of the heat sink 1A while focusing it.

[0027] Furthermore, the optical unit 101 can adjust the spot diameter of the laser light L irradiated onto one surface of the substrate 2 by moving the lens in the optical axis direction of the laser light L.

[0028] The scanning unit 102 scans the laser light L within the surface of the substrate 2 by moving either the stage 106 on which the heat sink 1A is placed or the device body 105 relative to the other.

[0029] In the laser measurement device 100 , it is also possible to rotate the stage 106 and move the device body 105 relative to the stage 106 in a direction perpendicular to the plane of the substrate 2 .

[0030] The light receiving unit 103 includes a light receiving element 1031 such as a CCD or CMOS, receives the laser light L reflected and returned from one surface of the substrate 2 of the heat sink 1A, and transmits a light reception signal to the calculation unit 104. In addition, the optical unit 101 transmits an output light signal of the laser light L to the calculation unit 104.

[0031] The calculation unit 104 measures the difference in distance (height difference) between one surface (bottom surface) of the substrate 2 and the top surface of the pin fin 3 based on the light output signal from the optical unit 101 and the light receiving signal from the light receiving unit 103, and calculates the height of the multiple pin fins 3 from the measurement results.

[0032] The measurement method of the laser measurement device 100 is not particularly limited, and examples thereof include a triangulation method, a time-of-flight method such as a phase difference distance method or a pulse propagation method, and the like.

[0033] (Laser measurement method) In the laser measurement method (height measurement method) of this embodiment, as shown in FIG. 5 , the above-mentioned laser measurement device 100 is used to irradiate one surface of the substrate 2 of the heat sink 1A, which is the object to be measured, with concentrated laser light L, and while scanning the laser light L within the surface of the substrate 2, the laser light L reflected and returned from the one surface of the substrate 2 of the heat sink 1A is measured, thereby measuring the heights of the multiple pin fins 3.

[0034] That is, the height of the pin fins 3 can be measured by measuring the difference in distance (height difference) between one surface (bottom surface) of the substrate 2 and the top surface of the pin fin 3 .

[0035] In this embodiment, the spot diameter of the laser light L is approximately 500 μm at the maximum at the measurement point.

[0036] In the laser measurement method of this embodiment, the heights of the pin fins 3 are measured while scanning the laser light L in a third direction D3, as indicated by the arrow "A" in FIG.

[0037] That is, the scanning direction of the laser light L is the third direction D3 in which the distance between two adjacent pin fins 3 out of the four adjacent pin fins 3 in the first direction D1 and the second direction D2 described above is greater than the distance in the first direction D1 and the distance in the second direction D2.

[0038] This makes it possible to increase the distance over which the laser light L scans between adjacent pin fins 3, thereby stabilizing the measurement results.

[0039] 6, the spot diameter of the laser light L is preferably smaller than the diameter of the pin fin 3, and more preferably smaller than the diameter of the gap "G" formed between three adjacent pin fins 3 of the above-mentioned four adjacent pin fins 3. In FIG. 6, gap G is the gap formed between three pin fins 3 of the above-mentioned four adjacent pin fins 3, such that the triangle formed by connecting the centers of gravity of the pin fins 3 forms a triangle with no obtuse angle in plan view.

[0040] This makes it possible to avoid interference of the laser light L between adjacent pin fins 3, while using laser light L with a larger spot diameter, thereby increasing the tolerance for positional deviation of the laser light L relative to the pin fin 3 when scanning the laser light L.

[0041] Furthermore, as shown by arrow B in Figure 6, when laser light L' is scanned in the first direction D1, if the spot diameter of this laser light L' is not made smaller than the inner spacing between adjacent pin fins 3 in the first direction D1, the spot of laser light L' irradiated between adjacent pin fins 3 will interfere with the two pin fins 3.

[0042] In contrast, in the laser measurement method of this embodiment, by scanning the laser light L in the third direction D3 described above, it is possible to accurately measure the heights of multiple pin fins 3 on the heat sink 1A while preventing the spot of the laser light L irradiated between adjacent pin fins 3 from interfering with the pin fins 3.

[0043] In the above embodiment, the heat sink 1A is illustrated in which the triangle formed by connecting the centers of gravity of three adjacent pin fins 3 when viewed in plan is an equilateral triangle, but the present invention is not limited to this. The same method can be applied to any heat sink in which adjacent pin fins are regularly arranged so that they are offset from one another in the first direction D1 and the second direction D2.

[0044] Second Embodiment Next, as a second embodiment of the present invention, a laser measurement method (height measurement method) will be described, one example of which is shown in a reference diagram in FIG.

[0045] 7 is a plan view of the heat sink 1B for explaining the laser measurement method according to the second embodiment. In the following explanation, the same parts as those in the heat sink 1A will not be described and will be denoted by the same reference numerals in the drawings.

[0046] 7, the heat sink 1B, which is the object to be measured in this embodiment, has a structure in which a plurality of pin fins 3 are arranged in a lattice pattern at intervals in a first direction D1 and a second direction D2 that intersect each other (orthogonal in this embodiment) within the plane of the substrate 2. In other words, the pin fins 3 are arranged in a uniform pattern in two orthogonal directions within the plane of the substrate 2.

[0047] In this embodiment, cylindrical pin fins 3 having the same diameter and height are arranged in a lattice pattern at equal intervals in the first direction D1 and the second direction D2.

[0048] In this embodiment, the third direction D3 is the direction in which the spacing between two adjacent pin fins 3 out of four adjacent pin fins 3 in the first direction D1 and the second direction D2 is greater than the spacing in the first direction D1 and the spacing in the second direction.

[0049] In this embodiment, it is possible to select, as the third direction D3, two directions that intersect with each other (orthogonal in this embodiment) within the plane of the substrate 2. In other words, in these two directions, the intervals between adjacent pin fins 3 in the third direction D3 are equal.

[0050] (Laser measurement method) In the laser measurement method of this embodiment, as shown in FIG. 5 , the laser measurement device 100 is used to irradiate one surface of the substrate 2 of the heat sink 1B, which is the object to be measured, with focused laser light L, and while scanning the laser light L within the surface of the substrate 2, the laser light L reflected and returned from the one surface of the substrate 2 of the heat sink 1B is measured, thereby measuring the heights of the multiple pin fins 3.

[0051] In the laser measurement method of this embodiment, the heights of the pin fins 3 are measured while scanning the laser light L in a third direction D3, as shown by the arrow C in FIG.

[0052] That is, the scanning direction of the laser light L is the third direction D3 in which the distance between two adjacent pin fins 3 out of the four adjacent pin fins 3 in the first direction D1 and the second direction D2 described above is greater than the distance in the first direction D1 and the distance in the second direction D2.

[0053] This makes it possible to increase the distance over which the laser light L scans between adjacent pin fins 3, thereby stabilizing the measurement results.

[0054] Furthermore, it is preferable that the spot diameter of the laser light L is smaller than the diameter of the pin fin 3, and more preferably, it is smaller than the gap G formed between three adjacent pin fins 3 out of the four adjacent pin fins 3 described above.

[0055] This makes it possible to avoid interference of the laser light L between adjacent pin fins 3, while using laser light L with a larger spot diameter, thereby increasing the tolerance for positional deviation of the laser light L relative to the pin fin 3 when scanning the laser light L.

[0056] In the laser measurement method of this embodiment, by scanning the laser light L in the third direction D3 described above, it is possible to accurately measure the heights of multiple pin fins 3 on the heat sink 1B while preventing the spot of the laser light L irradiated between adjacent pin fins 3 from interfering with the pin fins 3.

[0057] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0058] For example, in the above embodiment, heat sinks 1A and 1B are exemplified as measurement objects, but the measurement object is not necessarily limited to a heat sink, and may be any measurement object to which the laser measurement method of the present invention can be applied.

[0059] Furthermore, when the laser measurement device 100 is a V-shaped laser displacement meter in which thin linear or thin band-like laser light travels through different paths as incident light and reflected light, or a coaxial laser displacement meter in which incident light and reflected light travel through the same path, and in which the diameter of the laser light from the light-emitting part is wide and the diameter becomes narrower towards the tip, a particularly high effect can be obtained by applying the laser measurement method of the present invention.

[0060] Throughout this disclosure, singular expressions should be understood to include the plural concept unless otherwise specified. Therefore, singular articles (e.g., "a," "an," "the," etc. in English) should be understood to include the plural concept unless otherwise specified.

[0061] The effects of the present invention will be made clearer by the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0062] In this embodiment, the cylindrical pin fins 3 having the same diameter and height as described above are arranged in a staggered pattern at equal intervals in the first direction D1 and the second direction D2 on a heat sink 1A. The heights of the pin fins 3 were measured while scanning the heat sink 1A with laser light L in the third direction D3, and the results are shown in the graph in Figure 8.

[0063] On the other hand, as a comparative example, the heights of the pin fins 3 were measured while scanning the heat sink 1A with the laser light L' in the first direction D1, and the results are shown in the graph of FIG.

[0064] 8 and 9, the graphs are shown with the scales of the graphs successively enlarged in the order of upper (a), middle (b), and lower (c).

[0065] As shown in Figures 8 and 9, when laser light L is scanned in the third direction D3, it is possible to measure the heights of multiple pin fins 3 on the heat sink 1A with greater accuracy than when laser light L' is scanned in the first direction D1.

[0066] DESCRIPTION OF SYMBOLS 1A, 1B... Heat sink (measurement object) 2... Substrate (base material) 3... Pin fin (pin) 100... Laser measurement device 101... Optical section 102... Scanning section 103... Light receiving section 104... Calculation section 105... Device body 106... Stage D1... First direction D2... Second direction D3... Third direction L... Laser light G... Gap

Claims

1. A laser measurement method for measuring heights of a plurality of pins by irradiating a laser beam onto an object to be measured, the object having a plurality of pins standing from one surface of a substrate, the plurality of pins being arranged at intervals in a first direction and a second direction which intersect with each other within the surface of the substrate, and measuring the laser beam reflected and returning from the object to be measured while scanning the laser beam within the surface of the substrate, the method comprising: measuring heights of the plurality of pins while scanning the laser beam in a third direction in which the interval between two adjacent pins among four pins which are adjacent to each other in the first direction and the second direction is greater than the interval in the first direction and the interval in the second direction.

2. A laser measurement method according to claim 1, characterized in that the laser light is irradiated onto the object to be measured while being focused.

3. A laser measurement method according to claim 2, characterized in that the spot diameter of the laser light is made smaller than the gaps formed between three adjacent pins among the four pins.

4. A laser measurement method according to claim 1, wherein the plurality of pins are arranged in a staggered pattern within the surface of the base material.

5. The laser measurement method according to claim 1, wherein the plurality of pins are arranged in a lattice pattern within the surface of the base material.

6. The laser measurement method according to claim 1, wherein the object to be measured is a heat sink.

7. A laser measurement device which irradiates a laser beam onto an object to be measured, the object having a plurality of pins standing from one surface of a substrate, the plurality of pins being arranged at intervals in a first direction and a second direction which intersect with each other within the surface of the substrate, and measures the height of the plurality of pins by measuring the laser beam reflected back from the object to be measured while scanning the laser beam within the surface of the substrate, the laser measurement device comprising: an optical unit which irradiates the object to be measured with the laser beam; a scanning unit which scans the laser beam within the surface of the substrate; a light receiving unit which receives the laser beam reflected back from the object to be measured; and a calculation unit which calculates and measures the height of the plurality of pins based on the measurement result of the laser beam received by the light receiving unit, the laser measurement device being characterized in that the scanning unit scans the laser beam in a third direction in which the interval between two adjacent pins among four pins which are adjacent to each other in the first direction and the second direction is greater than the interval in the first direction and the interval in the second direction.

8. The laser measurement device according to claim 7, wherein the optical section irradiates the laser light onto the object to be measured while concentrating the laser light.

9. The laser measurement device according to claim 8, characterized in that the optical unit sets the spot diameter of the laser light to be smaller than the gaps formed between three adjacent pins among the four pins.

Images