Light irradiator

Abstract

The present invention provides a light irradiator that suppresses excessive thermal stress and excessive shock stress due to vibration on the components of the light irradiator, such as glass plates. [Solution] The light irradiator comprises a light source, a housing that houses the light source and has an opening in the direction of light emission from the light source, and a glass plate provided in the opening that transmits light from the light source. The device comprises a locking member for locking the glass plate to the housing, the locking member comprising a first locking portion that contacts the end of the main surface of the light-emitting side of the glass plate, a second locking portion made of an elastic material that contacts the side surface of the glass plate, and a mounting portion for attaching the locking member to the housing, the glass plate being detachable from the housing by disengaging contact between the locking member and the first locking portion.

Description

Technical Field

[0001] The present invention relates to a light irradiator.

Background Art

[0002] Light irradiators that irradiate a workpiece with light emitted from a light source such as an LED element are known. For example, Patent Document 1 describes a UV light irradiator that cures UV-curable ink applied on a workpiece. The light irradiator includes a housing that covers the light source, and takes out the light emitted from the light source through a window (opening) of the housing.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In order to prevent dust in the environment from adhering to the light source of the light irradiator, or to prevent an operator's fingers, tools, or other objects inside the light irradiator from coming into contact with the light source of the light irradiator, it is preferable to arrange a glass plate for protecting the light source in the light emission direction of the light source. The glass plate is detachably supported by the housing of the light irradiator.

[0005] The light irradiator is transported from the manufacturing and assembly site of the light irradiator to the place where the light irradiator is used. However, there is a gap between the glass plate and the housing to enable detachment and attachment, and this gap becomes a cause of vibration during transportation. Vibration generated during transportation increases the risk of damage to the glass plate and the housing.

[0006] Transporting the light irradiator with the glass plate removed avoids vibration problems. However, considering the increased risk of dust adhering to the light source during transport, and the increased risk of workers' hands or tools coming into contact with the light source at the installation site, it is desirable to transport the light irradiator with the glass plate attached to the housing from the manufacturing and assembly site to the usage location. This requires securing the glass plate with a small gap between it and the housing, while ensuring that vibrations during transport do not impose excessive impact stress on the glass plate and the housing.

[0007] Furthermore, the light irradiator heats up as light is emitted. This creates a difference in thermal expansion between the glass plate and the housing, which can generate excessive thermal stress in the glass plate. This excessive thermal stress can potentially damage the glass plate. Light irradiators used to heat objects, such as those used to heat semiconductor substrates, have a particularly large temperature rise, making them especially prone to generating excessive thermal stress and damaging the glass plate.

[0008] Therefore, the objective is to provide a light irradiator that suppresses excessive thermal stress and excessive shock stress due to vibration on the components of the light irradiator, such as glass plates. [Means for solving the problem]

[0009] The light irradiators disclosed herein are Light source and A housing that houses the light source and has an opening in the direction of light emission from the light source, A glass plate is provided in the opening and transmits light from the light source, The glass plate is secured to the housing by a locking member, The aforementioned locking member is A first locking portion that contacts the end of the main surface of the light-emitting side of the glass plate, A second locking portion made of an elastic material and in contact with the side surface of the glass plate, The locking member is provided with a mounting portion for attaching it to the housing, The glass plate can be attached to and detached from the housing by severing contact with the first locking portion of the locking member.

[0010] In the aforementioned light irradiator, the first locking portion contacts the main surface of the glass plate on the light-emitting side, preventing the glass plate from flying out and detaching from the housing. The second locking portion, made of an elastic material, contacts the side surface of the glass plate, supporting the glass plate while the elastic material absorbs vibrations of the glass plate during transport, thus suppressing excessive stress on the glass plate. Furthermore, the second locking portion, made of an elastic material, suppresses excessive thermal stress caused by the temperature rise of the light irradiator. The main surface of the glass plate refers to the surface with a significantly larger area than the other surfaces (side surfaces). The glass plate has two opposing main surfaces and a side surface located between the two main surfaces.

[0011] The housing has a notch that penetrates the side of the housing, When the glass plate is locked to the housing, the notch may provide a space in which the second locking portion exists.

[0012] The locking member may be attached to the housing so as to close the notch.

[0013] The housing may have a support surface that supports the end of the main surface of the light source side of the glass plate.

[0014] The locking member may be configured to be spaced apart from the support surface of the housing.

[0015] The second locking portion may be made of a leaf spring.

[0016] The locking member may be configured so as not to protrude from the housing in the direction of light emission.

[0017] The locking member may be configured so as not to protrude from the housing in a direction perpendicular to the light emission direction.

[0018] The locking members may be respectively provided on opposing side surfaces of the glass plate.

[0019] The light irradiator may be a light irradiator for heating a semiconductor substrate.

Effects of the Invention

[0020] It is possible to provide a light irradiator that suppresses excessive thermal stress applied to components of the light irradiator such as a glass plate and excessive impact stress caused by vibration.

Brief Description of Drawings

[0021] [Figure 1] It is a perspective view of one embodiment of the light irradiator. [Figure 2] It is a diagram in which the glass plate is removed from the light irradiator of Fig. 1. [Figure 3] It is an enlarged view of the region m1 in Fig. 2. [Figure 4] It is an enlarged perspective view of the locking member. [Figure 5] It is an enlarged perspective view of the locking member. [Figure 6] It is a partially enlarged view showing a glass plate fitted into a housing of the light irradiator. [Figure 7] It is a partially enlarged view of the periphery of the locking member of the light irradiator as viewed in the -Z direction. [Figure 8] It is a perspective view of the locking member according to a first comparative example. [Figure 9] It is a perspective view of a light irradiator using the locking member according to a second comparative example.

Mode for Carrying Out the Invention

[0022] Each embodiment of the light irradiator will be described with reference to the drawings. Note that the drawings disclosed in the present specification are merely schematic illustrations. That is, dimensional ratios in the drawings do not necessarily match actual dimensional ratios, and dimensional ratios also do not necessarily match between respective drawings.

[0023] The drawings are described with reference to the XYZ coordinate system. In this specification, when directions are expressed, positive and negative directions are distinguished and indicated with a sign, such as "+X direction" and "-X direction". When directions are expressed without distinguishing between positive and negative directions, they are simply described as "X direction". In other words, in this specification, when simply described as "X direction", both "+X direction" and "-X direction" are included. The same applies to the Y direction and Z direction.

[0024] [Overview of light irradiators] An example of a light irradiator for heating a semiconductor substrate will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of a light irradiator 100 for heating a semiconductor substrate. As shown in Figure 1, the light irradiator 100 comprises a housing 2 that houses a light source (not shown), a glass plate 3 that transmits light from the light source, and a locking member 5 that locks the glass plate 3 to the housing 2. Figure 2 is a perspective view of the light irradiator 100 shown in Figure 1 with the glass plate 3 removed.

[0025] In Figure 1, the housing 2 is long in the X and Y directions and short in the Z direction, and is flat overall, with a bottom, and has a rectangular tubular shape. Therefore, the housing 2 comprises a bottom, short side walls surrounding the bottom, and an opening 6 (see Figure 2). A glass plate 3 is placed in the opening 6 of the housing 2 (see Figure 1). When the housing 2 of this embodiment is viewed in the -Z direction, the housing 2 is square, but it does not necessarily have to be square. The housing 2 may be rectangular, triangular, pentagonal, hexagonal, or heptagonal or more, or it may be circular or elliptical. The material of the housing 2 is not particularly limited, but it is preferable that it be a material with excellent heat resistance and light resistance. From the viewpoint of heat resistance and light resistance, it is preferable that the housing 2 is made of a metallic material such as aluminum alloy or steel.

[0026] In Figure 1, the glass plate 3 is shown hatched with multiple diagonal lines. When the glass plate 3 of this embodiment is viewed in the -Z direction, the glass plate 3 is square, just like the housing 2, but it does not necessarily have to be square. The glass plate 3 may be rectangular, triangular, pentagonal, hexagonal, or heptagonal or more, just like the housing 2, or it may be circular or elliptical. The shape of the glass plate 3 should be determined according to the shape of the light source.

[0027] There are no particular restrictions on the dimensions of the glass plate 3, and the thickness and material of the glass plate 3 should be determined according to the dimensions of the glass plate 3. The shape and dimensions of the glass plate 3 should be such that the loss of light emitted from the light source is minimized when extracting it. For this reason, the shape and dimensions of the glass plate 3 should be determined according to the shape and dimensions of the light source. For example, the dimensions (maximum diameter or side length) of the glass plate 3 should be between 50 mm and 700 mm, preferably between 100 mm and 600 mm, and more preferably between 300 mm and 500 mm. The glass plate 3 may be, for example, fused silica glass, borosilicate glass, or soda-lime glass.

[0028] Two locking members 5 are arranged on each side of the housing 2. Therefore, locking members 5 are provided on both opposing sides of the glass plate 3. However, the number and position of the locking members 5 are not particularly limited. Details of the locking members 5 will be described later.

[0029] In Figure 2, the substrate 1 shown with multiple diagonal lines is a substrate 1 equipped with multiple light sources. The substrate 1 is located on the bottom inside the housing 2. Preferably, the dimensions of the substrate 1 in the X / Y direction are small enough that the light emitted from the light sources is not obstructed and can be emitted from the openings. Although not shown in Figure 2, the housing 2 has through-holes on its bottom or part of its side for passing power cables, communication cables, or refrigerant pipes that supply power to the substrate 1 (light sources), or for cooling the substrate 1 (light sources).

[0030] In the light irradiator 100 of this embodiment, LED elements are used as the light source. The emission spectrum of the light emitted by the LED elements shows a main intensity in the range of 300 nm to 900 nm, for example. The number of LED elements arranged on the substrate 1, the arrangement density of the LED elements, and the arrangement shape pattern of the LED elements are not particularly limited. The light emitted from the multiple LED elements passes through the glass plate 3 (not shown in Figure 2) placed in the aperture 6 and is emitted in the +Z direction.

[0031] The emission wavelength of the light source is set or selected according to the purpose of the light irradiator. A semiconductor laser element may also be used as the light source. Furthermore, a bare chip product (a product in which the light source elements are not covered by protective material) with only the light source elements placed on a substrate 1 may be used, as may a packaged product (a product in which each light source element is covered by protective material).

[0032] [Locking member] The details of the locking member 5 and its mounting method will be explained. Figure 3 is an enlarged view of area m1 in Figure 2. In Figure 3, of the surfaces constituting the housing 2, the surfaces along the XY plane are hatched with diagonal lines, while the other surfaces (surfaces along the YZ plane or XZ plane) are not hatched. As shown in Figure 3, the housing 2 has a step 2s on the inside of the side wall. The inner step 2s is the support surface for the glass plate 3. The glass plate 3 is supported by the housing 2 by placing the glass plate 3 on the support surface 2s such that the support surface 2s contacts the end of the -Z side main surface (light source side main surface) of the glass plate 3. A notch 2c is provided in the side wall of the housing 2. The locking member 5 is then placed in the notch 2c.

[0033] Figures 4 and 5 are enlarged perspective views of the locking member 5, respectively, with the viewing orientation of the locking member 5 differing between Figure 4 and Figure 5. Figure 6 shows the glass plate 3 fitted into the housing 2, with an enlarged view of the portion to which the locking member 5 is attached. To clearly show the shape of the portion of the housing 2 to which the locking member 5 is attached, the locking member 5 is not shown in Figure 6. Figure 7 is a partially enlarged view of the area around the positioned locking member 5 in the light irradiator 100, viewed in the -Z direction.

[0034] The locking member 5 comprises a first locking portion 5a that presses against the main surface of the glass plate 3, a back plate 5d, a second locking portion 5b that presses against the side surface of the glass plate 3, and a mounting portion 5e for attaching the locking member 5 to the housing 2 (see Figures 4 and 5). The first locking portion 5a and the back plate 5d are formed by bending a single sheet of metal at a right angle.

[0035] The first locking portion 5a contacts the end of the main surface of the light-emitting side of the glass plate 3 (see Figure 1). Without the first locking portion 5a, for example, if the light irradiator 100 is positioned so that the light emission direction is aligned with the direction of gravity, the glass plate 3 may fly out and detach from the housing 2. However, when using the locking member 5 of this embodiment, the first locking portion 5a holds the glass plate 3 in place, preventing the glass plate 3 from flying out and detaching from the housing 2. In Figure 4, the 5f attached to the center of the second locking portion 5b indicates the joint portion where the second locking portion 5b and the back plate 5d are joined. The joint between the second locking portion 5b and the back plate 5d may be performed by welding, for example.

[0036] The second locking portion 5b of the locking member 5 is made of an elastic material. In this embodiment, a leaf spring is used as the elastic material. The leaf spring in this embodiment is a double-wing spring, with cantilevered leaf springs extending on both sides from the joint portion 5f (see Figure 4). As shown in Figure 7, the tips 5b1 at the ends of the two wings of the second locking portion 5b contact the side surface of the glass plate 3, and the second locking portion 5b biases the side surface of the glass plate 3 in the +X direction. In other words, the elastic second locking portion 5b is always in a flexed state, with the two tips 5b1 in contact with the side surface of the glass plate 3. This makes it possible to mitigate the impact stress when the glass plate 3 separates from the second locking portion 5b due to vibration and then re-contacts the second locking portion 5b, and also allows thermal stress to be released when the temperature rises.

[0037] It is preferable that a pair of locking members 5 be positioned opposite each other with the glass plate 3 in between. When a pair of locking members 5 are positioned opposite each other with the glass plate 3 in between, it is preferable that the pair of locking members 5 use springs of the same design. For example, if the biasing force of the second locking portion 5b of one locking member 5 is too large, the spring of that locking member 5 may return to its natural length, and the tip 5b1 of the spring may separate from the glass plate 3. Furthermore, in the second locking portion 5b of the other locking member 5 positioned opposite each other with the glass plate 3 in between, even without vibration, the spring of that other locking member 5 may be compressed, and the side surface of the glass plate 3 may come into contact with the housing 2. To prevent such problems, it is preferable to position a pair of locking members 5 with springs of equal biasing force opposite each other with the glass plate 3 in between, so that the biasing forces are balanced. Since springs of the same design are typical examples of springs with equal biasing force, it is preferable that the pair of locking members 5 use springs of the same design. If the glass plate 3 is circular, it is preferable to arrange springs of the same design at equal circumferential intervals.

[0038] It is preferable to design the locking members 5 such that the biasing force of the second locking portion 5b of each locking member 5 is within an appropriate range so as to be sufficient to prevent damage to the glass plate 3 even when vibration or other forces are applied, while maintaining constant contact between the glass plate 3 and the second locking portion 5b.

[0039] The displacement of the second locking portion 5b is designed considering various conditions such as the weight of the glass plate 3 and the material of the second locking portion 5b, and is not particularly limited. However, if we were to specify, the biasing force from the locking member 5 may cause the tip 5b1 of the second locking portion 5b to be displaced by 0.05 mm to 5 mm in the direction away from the glass plate 3 (the -X direction in Figure 7), or by 0.08 mm to 3 mm. In this embodiment, the two tips 5b1 of the second locking portion 5b are fixed slightly apart from the support surface 2s of the housing 2. This prevents the tips 5b1 from being difficult to displace due to contact friction force from the support surface 2s.

[0040] The support surface 2s functions as a guide for the position of the locking member 5 when attaching it to the housing 2. Therefore, when the locking member 5 is temporarily attached to the housing 2, the second locking portion 5b may be in contact with the support surface 2s. After the locking member 5 is completely attached to the housing 2, the second locking portion 5b becomes floating (separated) from the support surface 2s. At this time, the locking member 5 contacts the glass plate 3 with its two ends 5b1, the first locking portion 5a and the second locking portion 5b. The first locking portion 5a contacts the surface 3s (see Figure 6) of the glass plate 3, providing a Z-direction positioning function for the glass plate 3 together with the support surface 2s. The two ends 5b1 of the second locking portion 5b contact the side surface 3w of the glass plate 3, providing an XY-direction positioning function for the glass plate 3 together with the other locking member 5. Details of the method for attaching the locking member 5 will be described later.

[0041] The glass plate 3 is detachably attached to the housing 2, and to mitigate thermal stress caused by the difference in thermal expansion between the glass plate 3 and the housing 2, when the glass plate 3 is fitted into the housing 2, there is a small gap G1 between the inner wall of the housing 2 and the side surface of the glass plate 3 (see Figure 7). Due to the presence of this gap G1, vibration of the glass plate 3 occurs during the transport of the light irradiator 100. However, since the tip 5b1 of the second locking portion 5b contacts the side surface of the glass plate 3 and the second locking portion 5b undergoes elastic deformation, the second locking portion 5b absorbs the vibration of the glass plate 3. This suppresses the impact stress applied to the glass plate 3. In addition, the second locking portion 5b also suppresses excessive thermal stress associated with the temperature rise during light irradiation.

[0042] The second locking portion 5b is not limited to a double-wing spring having cantilevered leaf springs on both sides as described above. For example, a cantilevered spring (single-wing spring) on ​​only one side may be used as the second locking portion 5b, or metal springs of various shapes such as coil springs, spiral springs, or torsion springs may be used. The second locking portion 5b should be made of an elastic material that elastically deforms to store force and returns to its original shape. As the material for the elastic material, for example, a metal material such as spring steel or nickel alloy may be used. Alternatively, a flexible polymer material including rubber may be used as the elastic material. Considering that the second locking portion 5b is exposed to high temperatures and light, it is more preferable that the metal material or flexible polymer material used is a material with excellent heat resistance and light resistance.

[0043] Regarding the first locking portion 5a, the portion of the first locking portion 5a described above is composed of a flat surface in the part facing the main surface of the glass plate 3. However, the first locking portion 5a may also be composed of a flat surface and an elastic member connected to the flat surface. Similar to the second locking portion 5b, various springs and materials can be applied to the elastic member used in the first locking portion 5a.

[0044] In this embodiment, the mounting portion 5e is a through hole provided in the back plate 5d. With a male screw (not shown) inserted into the through hole, it engages with a female screw 2e provided in the mounting portion 2d of the locking member 5 on the housing 2. The back plate 5d is sandwiched between the head of the male screw and the mounting portion 2d of the housing 2, thereby fixing the locking member 5 to the housing 2.

[0045] In this embodiment, the mounting portion 2d for attaching the locking member 5 to the housing 2 consists of a male screw, a female screw, and a through hole in the locking member 5. However, the locking member 5 may be fixed to the housing 2 by a method other than screws. For example, a fastener stopper (toggle latch) that hooks onto a projection and lowers a lever may be used, or a magnet or clip may be used.

[0046] The thickness t1 of the locking member 5 (see Figure 4) should be designed to be as thin as possible while still being able to secure the glass plate 3. The thickness t1 is preferably between 0.2 mm and 3.0 mm, and more preferably between 0.5 mm and 1.0 mm. The material of the locking member 5, excluding the second locking portion 5b, should preferably be a metal material such as stainless steel.

[0047] As shown in Figure 6, when the glass plate 3 is placed on the housing 2, the notch 2c provided in the housing 2 allows the inside and outside of the housing 2 to pass through, and the presence of the notch 2c can cause dust to enter the inside of the housing 2 (light irradiator). However, in this embodiment, when the locking member 5 is attached to the housing 2, the notch 2c is closed by the back plate 5d and the first locking portion 5a of the locking member 5, separating the inside of the housing 2 from the outside of the housing 2 and reducing the risk of dust entering the inside of the housing 2.

[0048] The housing 2 has a notch 2c that penetrates the side of the housing 2. When the glass plate 3 is locked to the housing 2, the notch 2c provides a space where the second locking portion 5b exists. The locking member 5 is attached to the housing 2 such that the first locking portion 5a and the back plate 5d close the notch 2c.

[0049] The glass plate 3 can be attached to and detached from the housing 2 by severing contact with the first locking portion 5a of the locking member 5. The method for removing the glass plate 3 will be explained with reference to Figure 6. First, the male screw is removed from the housing 2 and the locking member 5 is pulled out in the +Z direction. Then, the worker places their fingers in the notch 2c and, while holding down the side surface 3w of the glass plate 3 exposed through the notch 2c, lifts the glass plate 3 in the +Z direction. This allows the glass plate 3 to be removed from the housing 2.

[0050] As shown in Figure 6, the mounting portion 2d of the locking member 5 in the housing 2 is recessed by a depth t2 compared to the outer surface of the housing 2 on the ±Y sides of the mounting portion 2d. The mounting portion 2d is larger than the locking member 5, and the depth t2 is preferably greater than the thickness t1 of the locking member 5. By fitting the locking member 5 into the recessed mounting portion 2d, the locking member 5 is configured not to protrude from the housing 2 in the X / Y direction perpendicular to the light emission direction. This makes it difficult for the thin, low-rigidity locking member 5 to come into contact with peripheral equipment of the light irradiator 100, and also makes it easier to attach and detach the locking member 5 and the glass plate 3 in a light irradiation system in which the light irradiator 100 is incorporated into a narrow space.

[0051] As shown in Figure 3, the Z position of the first locking portion 5a of the locking member 5 is the same as the Z position of the side wall edge portion 2a of the housing 2. This is because the locking member 5 is designed not to protrude from the housing 2 in the direction of light emission. This makes it less likely for the light irradiator 100 to come into contact with peripheral equipment, and also makes it easier to attach and detach the locking member 5 and the glass plate 3 in a light irradiation system in which the light irradiator 100 is incorporated in a narrow space.

[0052] The details of the embodiments and modifications have been described above. However, the present invention is not limited in any way to the embodiments and modifications described above, and various changes or improvements may be made without departing from the spirit of the present invention. The locking member 5 is not limited to the shape described above. The light irradiator 100 described above was an example of a light irradiator for heating semiconductor substrates, but the above contents are also applicable to light irradiators for other purposes. [Examples]

[0053] [Random vibration test] A random vibration test was conducted using four light irradiators. The configurations of the four light irradiators (samples 1-4) are shown below. Sample 1: The light irradiator 100 shown in Figure 1 was used. When the housing 2 is viewed in the -Z direction, the housing 2 is square. The dimensions of the sides of the housing 2 extending in the X / Y directions are 400 mm. The material of the housing 2 is aluminum alloy A5052. The glass plate 3 is also square. Fused silica glass with a thickness of 3 mm was used for the glass plate 3. Two locking members 5, shown in Figures 3 to 7, were used on each side. The material of the first locking portion 5a and back plate 5d of the locking member 5 is stainless steel SUS304, and the material of the second locking portion 5b is spring stainless steel SUS304-CSP-H. Sample 2: A circular housing with a diameter of 182 mm was used when viewed in the -Z direction. The glass plate 3 was also circular. Fused silica glass with a thickness of 3 mm was used for the glass plate 3. The shape of the locking member 5 and the material of the housing are the same as in Sample 1. The material of the first locking portion 5a and the back plate 5d of the locking member 5 is SUS304 stainless steel, and the material of the second locking portion 5b is SUS304-CSP-1 / 2H, a spring stainless steel. Sample 3 (comparative configuration): This is the same light irradiator 100 as Sample 1, and the shape and dimensions of the housing 2 and glass plate 3 are the same as in Sample 1. However, in Sample 3, the locking member 95 shown in Figure 8 was used as the locking member. As shown in Figure 8, the locking member 95 has a first locking portion 5a to prevent the glass plate 3 from detaching from the housing 2 in the +Z direction, but does not have a second locking portion 5b. There is a slight gap between the housing 2 and the glass plate 3, and the glass plate 3 has some play in the X / Y direction relative to the housing 2. Sample 4 (comparative configuration): This is the same light irradiator as Sample 2, and the shape and dimensions of the housing 2 and glass plate 3 are the same as in Sample 2. However, in Sample 4, the locking member 95 shown in Figure 8 was used as the locking member. As shown in Figure 8, the locking member 95 has a first locking portion 5a to prevent the glass plate 3 from detaching from the housing 2 in the +Z direction, but does not have a second locking portion 5b. There is a slight gap between the housing 2 and the glass plate 3, and the glass plate 3 has some play in the X / Y direction relative to the housing 2.

[0054] For the random vibration tests, an i220 / SA1M single-axis electrodynamic combined vibration tester manufactured by IMV Corporation was used, and the random vibration tests were carried out in principle based on the conditions specified in Japanese Industrial Standard JIS Z 0232:2020 (Packaged goods - Vibration test methods). After the tests, the glass plates 3 were removed from each sample and visually inspected.

[0055] Table 1 shows the observation results of glass plate 3 after the random vibration test. The observation results are shown in three stages: A, B, and C. "A" means "no damage," and no damage to glass plate 3 was observed visually. "B" means "minor damage," and small scratches or trace amounts of deposits were observed on glass plate 3. "C" means "major damage," and significant scratches or a large amount of deposits were observed on glass plate 3.

[0056] [Table 1]

[0057] This confirms that the second locking portion 5b of the locking member 5, which is made of an elastic material, absorbs vibrations of the glass plate 3 and prevents damage to the glass plate 3.

[0058] [Calculation of surface pressure on the side of the glass] Even if there is a gap G1 between the housing 2 and the glass plate 3, vibrations can be suppressed if the glass plate 3 is firmly secured to the housing 2. On the other hand, the glass plate 3 and its surroundings, which constitute the emission surface of the light irradiator, are heated by light irradiation, but as mentioned above, the surface pressure applied to the side surface of the glass plate 3 may become excessive due to the difference in thermal expansion between the housing 2 and the glass plate 3 as the temperature rises. Therefore, two samples were considered, and the surface pressure applied to the side surface of the glass plate 3 was calculated for each of the two samples.

[0059] Let me explain the two samples. Sample 1: This is the same light irradiator 100 as Sample 1 used in the random vibration test. The light irradiator 100 uses two locking members 5 on each side, as shown in Figures 3 to 7. The other details of the light irradiator 100 are the same as those of Sample 1. Each locking member 5 presses and fixes the side surface of the glass plate 3. Even at room temperature, the locking members 5 apply a pressing force that is sufficient to prevent the glass plate 3 from vibrating. Sample 5: This sample assumes a light irradiator 200 as shown in Figure 9. The light irradiator 200 comprises a housing 2, a glass plate 3 positioned in the opening 6 of the housing 2, and a light source (not shown). Instead of using the locking members 5 shown in Figures 3 to 7 to secure the glass plate 3, a grub screw 20 is used. The grub screw 20 is inserted from outside the housing 2 into the female thread of the housing 2 and presses and fixes the glass plate 3 located inside the housing 2. Even at room temperature, the grub screw 20 applies a pressing force that is not sufficient to prevent the glass plate 3 from vibrating.

[0060] Assuming that the temperature of the locking member 5 (grub screw 20) and its surroundings rises by 100°C when the light irradiator (100,200) is irradiated with light, the amount of thermal expansion of the housing, locking member 5, and glass plate 3 was calculated, and the surface pressure applied to the side surface of the glass plate 3 was calculated. Table 2 shows the surface pressure (glass side surface pressure) applied to the side surface of the glass plate 3 after the temperature rises by 100°C and thermal expansion occurs.

[0061] [Table 2]

[0062] In the case of Sample 1, even when the glass plate 3, locking member 5, and housing 2 undergo thermal expansion, the glass side pressure only changes by about 20 MPa, and does not cause a pressure fluctuation that would result in a numerical difference of an order of magnitude. In contrast, in the case of Sample 5, when the glass plate 3, locking member 5, and housing 2 undergo thermal expansion, a significant increase in the glass side pressure is observed. As a result, it can be said that the surface pressure of Sample 1 is suppressed to less than 1% of that of Sample 5, which uses a grub screw 20. When the glass plate 3 is fused silica glass, its compressive strength is about 1100 MPa. Since the glass side pressure of Sample 1 is less than the compressive strength of fused silica glass, there is little risk of the locking member 5 damaging the glass plate 3. In contrast, since the glass side pressure of Sample 5 is greater than the compressive strength of fused silica glass, there is a risk that the glass side pressure from the grub screw 20 in Sample 5 may be excessively stressed due to thermal expansion, potentially damaging the glass plate 3. The same can be said for materials other than fused silica glass.

[0063] The tensile strength of fused silica glass is approximately 50 MPa. While surface pressure applied to the side of glass usually acts as a compressive force, if there are minute scratches or other defects in the glass, the surface pressure can locally act as a tensile force. When a surface pressure (compressive force) of 4000 MPa is applied to sample 5, a tensile force exceeding the tensile strength of the fused silica glass may be generated locally at the scratches, which can be one of the causes of fracture of the fused silica glass.

[0064] Based on the above, it was confirmed that Sample 1 and Sample 2 can provide a light irradiator that suppresses excessive thermal stress and excessive impact stress due to vibration on the glass component. [Explanation of Symbols]

[0065] 1: Circuit board 2: Cabinet 2a: Side wall edge 2c: Notch 2d: Mounting part 2e: Female thread 2s: Support surface (of the glass plate) 3: Glass plate 3w: (The side of a glass plate) 3s: (The surface of a glass plate) 5: Locking member 5a: First locking part 5b:Second locking part 5b1: (The tip of the second locking part) 5d: back plate 5e: Mounting part 5f: Joint (between the second locking part and the back panel) 6: (Opening of the enclosure) 95:Locking member 100,200: Light irradiator G1: Gap

Claims

1. Light source and A housing that houses the light source and has an opening in the direction of light emission from the light source, A glass plate is provided in the opening and transmits light from the light source, The glass plate is secured to the housing by a locking member, The aforementioned locking member is A first locking portion that contacts the end of the main surface of the light-emitting side of the glass plate, A second locking portion made of an elastic material and in contact with the side surface of the glass plate, The locking member is provided with a mounting portion for attaching it to the housing, The light irradiator is characterized in that the glass plate is detachable from the housing by severing contact with the first locking portion of the locking member.

2. The housing has a notch that penetrates the side of the housing, The light irradiator according to claim 1, characterized in that, when the glass plate is locked to the housing, the notch provides a space in which the second locking portion exists.

3. The light irradiator according to claim 2, characterized in that the locking member is attached to the housing so as to close the notch.

4. The light irradiator according to any one of claims 1 to 3, characterized in that the housing has a support surface that supports the end of the main surface of the light source side of the glass plate.

5. The light irradiator according to claim 4, characterized in that the locking member is configured to be spaced apart from the support surface of the housing.

6. The light irradiator according to any one of claims 1 to 3, characterized in that the second locking portion is composed of a leaf spring.

7. The light irradiator according to any one of claims 1 to 3, characterized in that the locking member does not protrude from the housing in the direction of light emission.

8. The light irradiator according to any one of claims 1 to 3, characterized in that the locking member does not protrude from the housing in a direction perpendicular to the light emission direction.

9. The light irradiator according to any one of claims 1 to 3, characterized in that the locking members are provided on opposing sides of the glass plate.

10. The light irradiator according to any one of claims 1 to 3, characterized in that the light irradiator is a light irradiator for heating a semiconductor substrate.

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