Light irradiation device

Abstract

To provide a light irradiation device capable of eliminating space restrictions caused by the presence of a screw head in an LED arrangement area as much as possible and preventing a screw from falling onto a workpiece side with as simple configuration as possible.SOLUTION: A light irradiation device comprises a substrate having a plurality of LEDs mounted on one surface thereof, and a support member supporting the substrate, where the substrate is fixed to the support member by a screw screwed in from a surface opposite to a mounting surface on which the LEDs are mounted, a screw hole for fixing the screws is formed in the substrate, and a plurality of screw holes is formed within an LED arrangement area, which is an area of the substrate where the LEDs are mounted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light irradiation device used for inspection, exposure, illumination, and the like. [Background technology]

[0002] In an inspection light irradiation device having a board mounted with multiple LEDs as shown in Patent Document 1 and a housing that houses the board, the board has conventionally been fixed to the housing by screwing a screw into a screw hole formed in the housing from the side of the board on which the LEDs are mounted, as shown in Figure 12. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-082423 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional light irradiation devices, the screw heads are present on the surface of the board on which the LEDs are mounted, and therefore the LED arrangement pitch needs to be at least wider than the outer diameter of the screw heads. More specifically, an insulating area is provided on the board to prevent electrical conduction between the screw head and the board or LEDs, and this insulating area is made larger than the outline of the screw head to take into account manufacturing variations, so the arrangement pitch of the LEDs needs to be even wider than the insulating area. Furthermore, if a screw comes loose when light is shining onto the object (work) from above, there is a risk that the screw will fall onto the workpiece, so a configuration to prevent the screw from falling, such as providing protective glass, is required. Furthermore, if the screw head is taller (protruding) than the LED, as in Figure 12, the light from the LED will be blocked by the screw head, reducing the uniformity of the irradiance distribution on the work surface.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a light-irradiation device that can eliminate space limitations caused by the presence of screw heads in the LED arrangement area as much as possible, and can prevent screws from falling onto the workpiece with as simple a configuration as possible. [Means for solving the problem]

[0006] That is, the light irradiation device according to the present invention includes a substrate having a plurality of LEDs mounted on one surface thereof, and a support member for supporting the substrate. The substrate is fixed to the support member by a screw that is screwed into the support member from a surface opposite to a mounting surface on which the LED is mounted, The present invention is characterized in that a screw hole for fixing the screw is formed in the substrate, and a plurality of the screw holes are formed within an LED arrangement area, which is an area of ​​the substrate where the LED is mounted.

[0007] With the light irradiation device configured in this way, even if it is necessary to tighten a number of screws in the LED arrangement area to firmly fix the board to a support member such as a case, the screw heads are not present in the LED arrangement area, so the degree of freedom in designing the LED arrangement area can be greatly improved. As a result, the LED arrangement pitch can be made smaller than before, and the irradiance distribution on the work surface can be improved compared to before.

[0008] Furthermore, since the area used for screwing in the LED arrangement area can be minimized, the heat dissipation or conductive pattern in the LED arrangement area can be arranged more freely than before. As a result, heat can be easily spread in the direction of the LED mounting surface of the board, improving heat dissipation performance. Since it is possible to pass more current while suppressing the effects of heat, it is also possible to increase the irradiance on the work surface compared to before.

[0009] Furthermore, even if the screw becomes loose and comes off, the screw head is present on the support member side, so the screw can be prevented from falling onto the workpiece. As a result, there is no need to install protective glass or the like on the workpiece side of the light irradiation device to prevent the screw from falling off, which reduces the manufacturing cost of the light irradiation device and eliminates the risk of glass breaking due to careless handling. In addition, the decrease in light utilization efficiency caused by, for example, Fresnel reflection on the surface of the protective glass can be reduced.

[0010] In a specific embodiment of the present invention, the substrate is made of a metal.

[0011] If the screw holes are bottomed holes formed from the support member side of the substrate toward the mounting surface side, the arrangement pitch of the LEDs on the LED mounting surface of the substrate and the freedom of the heat dissipation or conductive patterns can be further improved.

[0012] If the tip of the screw is flat, it is preferable because the engagement allowance of the screw in the screw hole can be made larger than when the tip of the screw is tapered.

[0013] In order to increase the irradiance on the work surface, it is preferable that the reflectance of the light of the wavelength emitted from the LED on the mounting surface is 50% or more.

[0014] The light source may further include an optical member disposed between the LED and the workpiece. Effect of the Invention

[0015] According to the present invention, since there can be no screw heads in the LED mounting area, the degree of freedom in designing the LED mounting area can be significantly improved. As a result, the LED arrangement pitch can be made smaller than before, and the uniformity of the irradiance distribution on the work surface can be improved. Also, the degree of freedom of the heat dissipation or conductive pattern in the LED arrangement area can be improved, and the heat dissipation performance can be improved. As a result, it is possible to increase the irradiance on the work surface compared to before. Furthermore, even if the screw becomes loose and comes off, the screw head is present on the support member side, so the screw can be prevented from falling onto the workpiece side. As a result, protective glass or the like for preventing the screw from falling onto the workpiece side of the light irradiation device can be omitted. [Brief description of the drawings]

[0016] [Figure 1] 1 is an overall schematic diagram of a light irradiation device according to one embodiment of the present invention. [Diagram 2] 3 is a schematic diagram of a substrate of the light irradiation device according to the embodiment. FIG. [Diagram 3] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 4] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram showing the behavior of light in the light irradiation device shown in FIG. [Figure 6] FIG. 5 is a schematic diagram showing the behavior of light in the light irradiation device shown in FIG. 3(a) and FIG. 4(a). [Figure 7] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 8] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 9] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 10] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 11] FIG. 13 is a schematic diagram illustrating a light irradiation device according to another embodiment of the present invention. [Figure 12] FIG. 1 is a schematic diagram showing a conventional light irradiation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of a light irradiation device 100 according to the present invention will be described with reference to the drawings.

[0018] A light irradiation device 100 according to this embodiment is used, for example, for inspecting various workpieces, and includes a substrate 1 and a support member 2 that supports the substrate 1, as shown in FIG.

[0019] The substrate 1 is equipped with a plurality of surface-mounted LEDs 11 that emit light of a specific wavelength. Note that the specific wavelength is not limited to a specific wavelength, and may include one or more types of wavelengths, or may include a certain wavelength range.

[0020] The support member 2, for example, constitutes a part of a rectangular parallelepiped housing C having an opening for emitting light from the above-mentioned LED 11 to the outside. In this embodiment, the support member 2 and the housing C are integrally formed, for example, and are made of metal.

[0021] The substrate 1 is accommodated inside the housing C so that light can be emitted from the opening. More specifically, the substrate 1 is fixed to the housing C with a surface 1b (hereinafter also referred to as the support member side surface) opposite to a surface 1a (hereinafter also referred to as the mounting surface) on which the LEDs 11 are mounted positioned on the support member 2 side, and with the surface 1b on the support member 2 side in direct contact with the support member 2.

[0022] The substrate 1, as shown in FIG. 2, for example, is a rectangular flat plate, and has an LED mounting area 111 on one surface 1a thereof, on which the LEDs 11 are mounted. In the LED arrangement region 111, an LED row 11A consisting of the LEDs 11 arranged in a row at an equal pitch along the long side of the substrate 1 is provided. In this embodiment, a plurality of the LED rows 11A are arranged in parallel at a pitch that is the same as or different from the pitch. In this specification, the LED arrangement region 111 refers to a region including mounting locations where the LEDs 11 are mounted and between these mounting locations, that is, a region surrounded by the LEDs 11 arranged on the outermost side among the group of LEDs 11 arranged at an equal pitch on the substrate 1. When a plurality of the substrates 1 are provided, one or more LED arrangement regions 111 are set in each substrate 1.

[0023] The substrate 1 is formed from a metal such as aluminum, and it is preferable that the reflectance of the light having a wavelength emitted from the LED 11 on the mounting surface 1a is 50% or more. Although not shown in the drawings, in the LED arrangement area 111 of the substrate 1, for example, conductive wiring for supplying power to the LEDs 11 and a heat dissipation pattern for dissipating heat generated in the LEDs are formed.

[0024] In this embodiment, a plurality of screw holes 3 are formed in the LED arrangement area 111 of the substrate 1, and a plurality of screws 4 are screwed into the screw holes 3 from the support member 2 side, thereby fixing the substrate 1 to the housing C.

[0025] The screw hole 3 is a female screw formed in the thickness direction of the substrate 1, and in this embodiment is a bottomed hole formed from the surface 1b side opposite to the mounting surface 1a.

[0026] The screw 4 has a screw head 4a and a threaded portion 4b extending from the screw head 4a toward the tip. The threaded portion 4b is formed with a male thread 4c that can be engaged and fixed into the screw hole 3. There is no need to prepare a special screw 4, and a commercially available screw (for example, a pan head screw or a CAP bolt) can be used. In this embodiment, the support member 2 is also formed with a screw accommodating hole 5 for accommodating the screw 4 therein. The screw accommodating hole 5 has a small inner diameter portion 5a and a large inner diameter portion 5b from the substrate 1 side of the support member 2 to the opposite side, and the screw portion 4b is accommodated in the small inner diameter portion 5a and the screw head 4a is accommodated in the large inner diameter portion 5b, so that, for example, the screw head 4a does not protrude outward from the housing C.

[0027] According to the light irradiation device 100 configured in this manner, the substrate 1 is fixed to the housing C by screwing in the screws 4 from the housing C side, so that even when a plurality of screws are fastened within the LED arrangement area 111, it is possible to eliminate space limitations due to the presence of the screw heads 4a within the LED arrangement area 111. As a result, by arranging the LEDs 11 as densely as possible within the LED arrangement area 111, it is possible to further improve the uniformity of the irradiance on the work surface compared to the conventional case.

[0028] Furthermore, since the screw head 4a is present on the side of the housing C, even if the screw 4 loosens and comes off, the screw 4 can be prevented from falling onto the workpiece.

[0029] Furthermore, since there is no restriction due to the presence of the screw head 4a in the LED mounting area 111 of the substrate 1, it is possible to greatly improve the design freedom of the wiring and heat dissipation pattern in the LED mounting area 111. As a result, it is possible to adopt a pattern that dissipates heat as easily as possible, so it is also possible to increase the irradiance on the work surface by passing a larger current through the LED 11 than before.

[0030] In this embodiment, furthermore, since the screw holes 3 are bottomed holes, no screw holes 3 are formed in the LED mounting area 111 of the substrate 1, and the tips of the screws 4 do not protrude, it is possible to further increase the degree of freedom in designing the arrangement pitch of the LEDs 11, wiring, heat dissipation pattern, and the like in the LED mounting area 111. Furthermore, since there are no screw holes 3 or tips of the screws 4, it is possible to further increase the light reflectance on the surface 1a of the substrate 1.

[0031] The present invention is not limited to the above-described embodiment. For example, in the above embodiment, the screw holes are blind holes, but the screw holes may be through holes as shown in Figs. When the screw holes are through holes, a sufficient amount of engagement can be ensured even if the substrate is thin. As a result, it is possible to make the substrate as thin as possible and reduce the overall thickness of the light irradiation device. In addition, by making the screw engagement as long as possible, the substrate and the housing can be in contact with each other with sufficient strength, which reduces the contact thermal resistance between the substrate and the housing and allows the heat from the LED to be dissipated more efficiently. If the screw holes are through holes, it is possible to fasten the board to the housing with a nut without threading the screw holes, but in the case of the present invention, the board is threaded and the screw is fixed, thereby preventing the nut from falling onto the work side.

[0032] As shown in Figures 3 and 4, the screws used in the present invention may have either a tapered tip or a flat tip. If the tip of the screw is flat as shown in Figures 4 and 5, even if the screw hole is a through hole as described above and the tip of the screw protrudes toward the direction of light irradiation from the LED, the protruding length can be kept as small as possible to prevent a decrease in the uniformity of the irradiance distribution on the work surface caused by light from the LED hitting the screw.

[0033] Furthermore, if there is light that is reflected from the workpiece side and returns to the surface of the substrate, the light that hits the tip of the screw is likely to return directly to the workpiece side, so a flat screw tip rather than a tapered one can improve the uniformity of the irradiance distribution on the workpiece surface and the irradiance, as shown in Figure 6.

[0034] In the case where the screw hole is a through hole, the screw may be any screw that can fix the board and the housing by fitting into the female thread of the screw hole, and the position of the tip of the screw is not particularly limited as shown in Figures 3 and 4, but it is preferable that the tip of the screw is located closer to the board than the end of the LED opposite the board in the axial direction of the screw as shown in (a) in each figure so as not to block the light emitted from the LED toward the work as much as possible. The tip of the screw may not protrude from the surface of the board on the side where the LED is mounted, but may be inside the through hole (b), or the tip of the screw may be located on the same plane as the surface of the board on the side where the LED is mounted (c). By positioning the tip of the screw closer to the substrate in the axial direction of the screw than the end of the LED opposite the substrate, it is possible to increase the design freedom, for example by positioning the optical component 6 as close as possible to the LED, as shown in Figure 9, to reduce the size of the device or achieve higher optical performance.

[0035] The light irradiation device may further include one or more optical members 6 disposed between the substrate and the workpiece, as shown in, for example, FIGS. The optical member 6 has the properties of diffusing, transmitting, reflecting the light from the LED, or a combination of these, and examples thereof include a diffuser plate, a lens, a half mirror, and a cover glass. Even if a part of the light from the LED that reaches the optical member 6 is returned to the substrate side due to Fresnel reflection on the surface of the optical member 6, for example, the absence of screw heads in the LED arrangement area increases the probability that the light can be further reflected by the substrate and reused, and the light utilization efficiency can be increased compared to conventional products.

[0036] In addition to the above-mentioned configuration, the light irradiation device may further include a heat dissipation structure 7 such as a heat sink, as shown in Figures 10 and 11. In this case, the heat sink may be provided so as to contact the surface of the housing opposite to the substrate, and the heat sink may have a through hole for receiving the screw therein. With the structure shown in Figure 11, the substrate can be removed without removing the heat dissipation structure 7 such as the heat sink, so that the ease of assembly is not impaired.

[0037] The present invention is not limited to applications for workpiece inspection, but can be widely applied to light irradiation devices for exposure and other light irradiation devices.

[0038] The materials constituting each part are not limited to those described above, and can be changed as appropriate depending on the purpose and use. For example, the screw holes may be formed by insert nuts instead of directly forming them in the board. Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0039] 100...Light irradiation device 1. Circuit Board 1a Mounting surface 11 LED 111...LED installation area 2 Support member C···Case 3 Screw holes 4 screws 6 Optical components

Claims

1. A substrate having a plurality of LEDs mounted on one surface thereof and a support member supporting the substrate, The substrate is fixed to the support member by a screw that is screwed into the support member from a surface opposite to a mounting surface on which the LED is mounted, A light irradiation device characterized in that a screw hole for fixing the screw is formed in the substrate, and the screw hole is formed in a plurality of areas within an LED arrangement area, which is an area of ​​the substrate where the LED is mounted.

2. The light irradiation device according to claim 1 , wherein the screw hole is a blind hole formed from the surface of the substrate on the support member side toward the mounting surface.

3. The light irradiation device according to claim 1 , wherein the tip of the screw is flat.

4. The light irradiation device according to claim 1 , wherein the light reflectance on the mounting surface is 50% or more.

5. The light irradiation device according to claim 1 , further comprising an optical member disposed between a workpiece to be irradiated and the LED.

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