JP7645106B2 - Protective cover - Google Patents

Description

The present invention relates to a protective cover made of a light-transmitting amorphous or crystalline material.

Optical devices that emit or receive infrared light, visible light, ultraviolet light, etc. with wavelengths between 150 nm and 15,000 nm use optical device elements (also simply called optical elements) such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes). These optical elements are protected from the outside by being covered with a protective cover that includes a light-transmitting cover glass (amorphous or crystalline material).

The protective cover is constructed by sealing a cover glass with low-melting glass so as to cover a window in the ceiling of a hat-shaped cap, and the flange part of the cap is fixed to the stem on which the optical element is mounted by welding, soldering, etc. in a hermetically sealed manner. In addition, the cap is formed by pressing a metal plate, and is excellent in terms of its high strength and high heat resistance (see, for example, Patent Document 1).

JP 2010-40647 A (page 2, figure 1)

As optical devices have become smaller in recent years, there is a demand for smaller protective covers as well, which requires that the cap be made smaller and thinner in external dimensions, making it difficult to maintain the strength of the cap while ensuring sufficient storage space for the optical elements inside the cap. For example, if an optical device is placed sideways so that light is emitted/incident in the horizontal direction, the ceiling side of the cap will tilt slightly when it is subjected to a load such as vertical vibration, deteriorating the perpendicularity of the cover glass relative to the light emission/input, and there is a risk of compromising the precision of the optical device.

The present invention was made with a focus on these problems, and aims to provide a protective cover that ensures sufficient storage space for optical elements while maintaining the orthogonality of the optical element's light emission/input.

In order to solve the above problems, the protective cover of the present invention comprises:
A protective cover comprising a cap having a peripheral wall and a ceiling, and an amorphous or crystalline material having optical transparency, the amorphous or crystalline material being attached to a window formed in the ceiling of the cap,
The cap is produced by pressing,
The peripheral wall of the cap is characterized by having a thick portion connected to the thin portion and disposed on the window side.
According to this feature, since the thick portion is disposed on the window side of the peripheral wall and the rigidity of the window side of the cap is high, it is possible to secure a sufficient space for accommodating the optical element while maintaining the orthogonality between the amorphous or crystalline material and the outgoing/incoming light. Furthermore, since the cap is manufactured by pressing, it can be manufactured at low cost. For example, even if the protective cover is used in a horizontal position and the cap is subjected to an external force in the vertical direction due to vibration or the like, the window side of the cap deforms so as to move approximately parallel to the stem, so that the orthogonality between the amorphous or crystalline material and the outgoing/incoming light is maintained.

The thick-walled portion and the thin-walled portion are characterized in that they have substantially the same outer diameter.
According to this feature, the cap can be formed compactly without being bulky in the width direction while ensuring a space for accommodating the optical element.

The ceiling is formed to be thinner than the thick portion.
This feature allows the weight of the upper part of the cap to be reduced.

The ceiling is formed by pressing.
This feature allows a thin, smooth surface to be prepared at low cost.

The cap is molded from a single piece of material of uniform thickness.
According to this feature, the cap is molded integrally, so that strength can be ensured.

1 is a front cross-sectional view showing an example in which a protective cover according to an embodiment of the present invention is applied to protection of an element for an optical device. FIG. 2 is an exploded perspective view of a protective cover before assembly, with a portion of the cap cut away in the embodiment. FIG. 2 is a front cross-sectional view showing a protective cover in an embodiment. FIG. 2A is a schematic diagram showing the fiber flow of a cap produced by press working, and FIG. 2B is a schematic diagram showing the fiber flow of a cap produced by cutting working. 11 is an explanatory diagram showing an embodiment in which the protective cover is placed sideways and the cap is deformed. FIG.

The following describes the implementation of the protective cover according to the present invention.

The protective cover and its manufacturing method according to the first embodiment will be described with reference to Figures 1 to 5. In the following description, the front side of the paper in Figure 1 is the front side (front side) of the protective cover, and the top, bottom, left and right directions when viewed from the front side will be used as references.

As shown in FIG. 1, the optical device 1 is mainly composed of a number of optical device elements 2 (optical elements), a disk-shaped metal stem 3 on which the optical device elements 2 are mounted, terminals 4 that are disposed and fixed in through holes in the stem 3 and are electrically connected to the optical device elements 2 by wires (not shown), and a protective cover 5 that is fixed to the stem 3 and hermetically seals and protects the optical device elements 2.

As shown in Figures 2 and 3, the protective cover 5 includes a metal cap 6 that has a generally hat-shaped structure when viewed from the front, and a cover glass 11 (amorphous or crystalline material) that seals a circular window 8 formed in the ceiling 16 of the cap 6 from below. A low-melting-point glass 9 is disposed between the cap 6 and the cover glass 11, and the cover glass 11 is fused to the cap 6.

The cap 6 is formed by pressing a thin plate of an Fe-Ni alloy, and is mainly composed of a ceiling 16 that is generally annular and of generally uniform thickness, a peripheral wall 62 that extends downward from the outer diameter side of the ceiling 16 and forms a cylindrical shape, and a flange portion 63 that extends a predetermined distance from the lower end of the peripheral wall 62 to the outer diameter side. The cap 6 is preferably made of an Fe-Ni alloy from the viewpoints of mechanical strength and a thermal expansion coefficient close to that of the cover glass 11, but other metal materials may also be used.

The peripheral wall 62 is composed of a thin portion 62A and a thick portion 62B. The thin portion 62A is formed on the lower side of the peripheral wall 62, and the thick portion 62B is formed on the upper side of the peripheral wall 62, continuing from the thin portion 62A. The thin portion 62A and the thick portion 62B have approximately the same outer diameter, the inner diameter of the thin portion 62A is larger than the inner diameter of the thick portion 62B, and the thin portion 62A is thinner than the thick portion 62B.

Referring to FIG. 3, in this embodiment, the thickness T1 of the thin portion 62A is approximately 0.2 mm, and the thickness of the thick portion 62B is approximately two to three times the thickness T1 of the thin portion 62A. The thickness T3 of the ceiling 16 is approximately the same as the thickness T1 of the thin portion 62A, or is slightly thicker. As will be described later, the thin portion 62A and the thick portion 62B are formed during the press processing of the cap 6.

The cover glass 11 is disk-shaped and is composed of a top surface 11a, a bottom surface 11b, and a peripheral surface 11c. The cover glass 11 is fused to the bottom surface 16a of the ceiling 16 of the cap 6 from the top surface 11a side via the low-melting point glass 9.

The low-melting glass 9 is a ring-shaped tablet of bismuth- or tellurium-based low-melting glass before sealing (see FIG. 2). As described below, the low-melting glass 9 melts when heated, and seals the cap 6 and the cover glass 11. The low-melting glass 9 is preferably glass that has a low glass transition temperature and softens at 600°C or less. The low-melting glass 9 may be other than the bismuth- or tellurium-based glass described above, and powdered glass may be formed into a tablet, or a paste may be applied.

The following describes the manufacture and assembly of the protective cover 5. First, the cap 6 will be described with reference to Figure 2.

First, a cylindrical punch is pressed multiple times by a press machine against a thin metal plate of uniform thickness placed on a base to form a thin portion 62A, a thick portion 62B that is thicker than the thin portion 62A, and a ceiling 16. A window 8 is also formed in the ceiling 16 by drilling a hole. In this way, the cap 6 is manufactured as shown in FIG. 2.

Next, referring to Figure 2, the assembly and sealing of the cover glass 11 to the cap 6 will be described. The cap 6, low melting point glass 9, and cover glass 11 are stacked in this order, and placed in a heating furnace (not shown). They are heated to 500 degrees in a nitrogen gas atmosphere and held there for 10 minutes, melting the low melting point glass 9 and fusing and sealing the cover glass 11 to the underside 16a of the ceiling 16 of the cap 6.

Here, we will explain the fiber flow of cap 66 manufactured by pressing as shown in FIG. 4(a), and the fiber flow of cap 6 of this embodiment manufactured by cutting as shown in FIG. 4(b). Fiber flow refers to the flow of fibrous metal structure that can be confirmed using a microscope, etc., and differs depending on the processing method. The shapes of cap 66 and cap 6 are approximately the same.

As shown in FIG. 4(a), the cap 6 manufactured by pressing has fiber flows formed along the surface contour of the cap 6. This makes the cap 6 more resistant to tensile stress than the cap 66. Furthermore, in steps 1 to 3, the thin-walled portion 62A of the peripheral wall 62 and the ceiling 16 are formed thin by drawing, so the distance between the fiber flows of the thin-walled portion 62A and the ceiling 16 is narrow. This makes the impact resistance against external forces and fatigue strength higher than the machined cap 66. This makes it possible to maintain strength even when the thin-walled portion 62A is formed thin.

For reference, the fiber flows of the cap 66, which is machined from a cylindrical metal material, extend radially, approximately perpendicular to the axial direction in which the peripheral wall 66A rises, as shown in FIG. 4(b), and the distance between adjacent fiber flows in the peripheral wall 66A and the ceiling 66B is approximately uniform and long. Furthermore, the length from the starting end to the terminal end of each fiber flow is short.

In addition, as shown in FIG. 5, if the optical device 1 is placed sideways and used for a long period of time, the cap 6 may be deformed due to vertical vibrations on the optical device 1. The peripheral wall 62 of the cap 6 of the present invention has a thick portion 62B arranged circumferentially on the window 8 side, so that the rigidity of the window 8 side of the cap 6 is high, and as shown in FIG. 5, the window 8 side of the cap 6 is deformed so as to move approximately parallel to the stem 3. This maintains the orthogonality of the light emission/incoming between the cover glass 11 and the optical device element 2.

In addition, as shown in FIG. 3, the thickness from the outer circumferential surface to the inner circumferential surface of the thick-walled portion 62B is sufficiently large, so that the area H consisting of the upper surface of the ceiling 16 and the upper surface of the thick-walled portion 62B can be secured as a highly rigid flat surface, making it easy to perform welding or the like on the area H.

In addition, the fiber flow in region H is bent at approximately 90 degrees from the peripheral wall 62 extending in the axial direction and continues in the inner diameter direction, so that the cap 6 is less likely to deform and the orthogonality of the light emission/input between the cover glass 11 and the optical device element 2 is maintained (see FIG. 4(a)).

In this way, the protective cover 5 includes the cap 6, which is composed of the peripheral wall 62 and the ceiling 16, and the cover glass 11, and the cover glass 11 is attached to the window 8 formed in the ceiling 16 of the cap 6. The cap 6 is manufactured by pressing, and the peripheral wall 62 of the cap 6 includes the thick portion 62B that is connected to the thin portion 62A and is disposed on the window 8 side, so that the orthogonality between the cover glass 11 and the light emission/incoming can be maintained while a sufficient space can be secured to store the optical device element 2. Furthermore, since the cap 6 is manufactured by pressing, it can be manufactured inexpensively. For example, even if the protective cover 5 is used in a horizontal position and the cap 6 is subjected to an external force in the vertical direction due to vibration or the like, the window 8 side of the cap 6 deforms so as to move approximately parallel to the stem 3, so that the orthogonality between the cover glass 11 and the light emission/incoming can be maintained.

In addition, the outer diameters of the thick-walled portion 62B and the thin-walled portion 62A are formed to be approximately the same, so that the cap 6 can be formed compactly without being bulky in the width direction while ensuring a storage space for the optical device element 2.

In addition, the ceiling 16 is formed thinner than the thick portion 62B, which reduces the weight of the upper part of the cap 6. Therefore, when the cap 6 is placed sideways, it is less likely to deform even if it receives an external force in the vertical direction due to vibration, etc.

In addition, the ceiling 16 is formed by pressing, so a thin, smooth surface can be produced at low cost.

In addition, the cap 6 is molded from a single piece of material with a uniform thickness, so the cap 6 is molded as a single unit, ensuring strength.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

For example, in the above embodiment, an Fe-Ni alloy is used as the material for the cap 6, but the present invention is not limited to this, and for example, a metal material other than an Fe-Ni alloy may be used as the material.

In addition, in the above embodiment, a disk-shaped cover glass 11 is attached to the window 8, but the present invention is not limited to this. For example, a spherical lens, an aspherical lens, or a fused lens may be attached.

In addition, in the above embodiment, a flange portion 63 is formed at the lower end of the peripheral wall 62 of the cap 6, but the present invention is not limited to this, and the cap may be a cylindrical cap with a bottom that omits the flange portion.

In addition, in the above embodiment, the thin-walled portion 62A and the thick-walled portion 62B have been illustrated as having substantially the same outer diameter, but the present invention is not limited to this. The thin-walled portion 62A and the thick-walled portion 62B may have substantially the same inner diameter but different outer diameters as the cap 6.

In addition, in the above embodiment, the window 8 is shown to be circular, but the present invention is not limited to this, and the window may be formed in a shape other than a circle, such as a square, polygonal, or elliptical shape.

In the above embodiment, the cap 6 is illustrated as being circular when viewed from above, but the present invention is not limited to this, and the cap may be shaped other than circular when viewed from above, such as a square, polygonal, or elliptical shape when viewed from above.

In addition, in the above embodiment, the thickness T3 of the ceiling 16 is approximately the same as or slightly thicker than the thickness T1 of the thin-walled portion 62A, but the present invention is not limited to this, and the thickness T3 of the ceiling 16 may be thinner than the thickness T1 of the thin-walled portion 62A.

In addition, in the above embodiment, the peripheral wall 62 is formed from a thin portion 62A and a thick portion 62B, each having a different thickness, but the present invention is not limited to this, and the peripheral wall 62 may be formed from three or more peripheral walls each having a different thickness.

In the above embodiment, the ceiling 16 is formed by pressing so that it is approximately perpendicular to the peripheral wall 62, but the present invention is not limited to this. After the ceiling 16 and the peripheral wall 62 are formed by pressing, the ceiling 16 may be bent so that it is approximately perpendicular to the peripheral wall 62.

1 Optical device 2 Elements for optical devices (optical elements)
3 Stem 4 Terminal 5 Protective cover 6 Cap 8 Window 9 Low melting point glass 11 Cover glass (amorphous or crystalline material)
16 Ceiling 62 Peripheral wall 62A Thin wall portion 62B Thick wall portion 63 Flange portion

Claims (4)

A protective cover comprising a cap having a peripheral wall and a ceiling, and an amorphous or crystalline material having optical transparency, the amorphous or crystalline material being attached to a window formed in the ceiling of the cap,
The cap is produced by pressing,
the peripheral wall of the cap includes a thick-walled portion that is connected to the thin-walled portion and that is disposed on the window side ;
The ceiling is a protective cover formed to be thinner than the thick portion . The protective cover according to claim 1, characterized in that the thin-walled portion and the thick-walled portion are formed with approximately the same outer diameter. 3. The protective cover according to claim 1 , wherein the ceiling is formed by pressing. 4. The protective cover according to claim 1 , wherein the cap is molded from a single piece of material having a uniform thickness.

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