Protective cover

Abstract

To provide a protective cover that maintains the orthogonality of light emission / injection of an optical element while securing a sufficient storage space for the optical element.SOLUTION: A protective cover 5 includes a cap 6 composed of a peripheral wall 62 and a ceiling, and a cover glass 11, and a cover glass 11 is attached to a window 8 formed in the ceiling of the cap 6, and the cap 6 is manufactured by press working, and the peripheral wall 62 of the cap 6 has a thick portion 62B that is arranged on the window 8 side and connected to a thin portion 62A.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a protective cover using a light-transmitting amorphous or crystalline material. [Background technology]

[0002] Optical devices that emit or receive infrared light, visible light, ultraviolet light, etc. with wavelengths of 150 nm to 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 covered with a protective cover having a light-transmitting cover glass (amorphous or crystalline material) to protect them from the outside.

[0003] The protective cover is configured by sealing a cover glass with low melting point glass so as to cover a window in the ceiling of a hat-shaped cap, and the flange part of the cap is fixed in a hermetically sealed manner to a stem on which an optical element is mounted by welding, brazing material, etc. In addition, the cap is formed by pressing a metal plate, and is excellent in terms of its high strength and high heat resistance (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-40647 A (page 2, figure 1) Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, as optical devices have become smaller, there has been a demand for smaller protective covers, and it has become necessary to form the cap with a smaller outer shape and thinner wall, making it difficult to maintain the strength of the cap while ensuring sufficient storage space for the optical elements inside the cap. For example, when an optical device is placed sideways so that light is emitted / incident in the horizontal direction, if a load such as vibration is applied in the vertical direction, the ceiling side of the cap will tilt slightly, deteriorating the perpendicularity of the cover glass with respect to the light emission / input, and there is a risk of compromising the precision of the optical device.

[0006] The present invention has been made in response to these problems, and aims to provide a protective cover that ensures sufficient storage space for optical elements while maintaining the orthogonality of the exit / entrance light of the optical elements. [Means for solving the problem]

[0007] 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 that is continuous with the thin portion and is 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 light emission / incoming. 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 light emission / incoming is maintained.

[0008] 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.

[0009] 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.

[0010] The ceiling is formed by pressing. This feature allows a thin, smooth surface to be prepared at low cost.

[0011] 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. [Brief description of the drawings]

[0012] [Figure 1] 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. [Diagram 2] FIG. 2 is an exploded perspective view of a protective cover before assembly, with a portion of the cap cut away in the embodiment. [Diagram 3] FIG. 2 is a front cross-sectional view showing a protective cover in the embodiment. [Figure 4] 1A is a schematic diagram showing the fiber flow of a cap produced by press working, and FIG. 1B is a schematic diagram showing the fiber flow of a cap produced by cutting working. [Diagram 5] 11 is an explanatory diagram showing an aspect in which the protective cover in the embodiment is placed sideways and the cap is deformed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A protective cover according to the present invention will be described below with reference to the following examples. EXAMPLES

[0014] A protective cover according to a first embodiment and a manufacturing method thereof will be described with reference to Fig. 1 to Fig. 5. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of the protective cover, and the up, down, left and right directions when viewed from the front side will be used as references.

[0015] As shown in FIG. 1, 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 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 stem 3 and hermetically seals and protects the optical device elements 2.

[0016] 2 and 3, the protective cover 5 includes a metal cap 6 having a generally hat-shaped structure when viewed from the front, and a cover glass 11 (amorphous or crystalline material) that seals from below a window 8 serving as a circular opening formed in a ceiling 16 of the cap 6. 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.

[0017] The cap 6 is formed by pressing a thin plate of an Fe-Ni alloy, and is mainly composed of a ceiling 16 having a substantially annular shape and a substantially uniform thickness, a peripheral wall 62 extending downward from the outer diameter side of the ceiling 16 to form a cylindrical shape, and a flange portion 63 extending a predetermined distance toward the outer diameter side from the lower end of the peripheral wall 62. 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 be used.

[0018] 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 are formed to have substantially the same outer diameter, and the inner diameter of the thin portion 62A is formed to be larger than the inner diameter of the thick portion 62B, so that the thin portion 62A is thinner than the thick portion 62B.

[0019] 3, in this embodiment, the thickness T1 of the thin portion 62A is about 0.2 mm, and the thickness of the thick portion 62B is about two to three times the thickness T1 of the thin portion 62A. The thickness T3 of the ceiling 16 is approximately the same as or slightly thicker than the thickness T1 of the thin portion 62A. As will be described later, the thin portion 62A and the thick portion 62B are formed when the cap 6 is pressed.

[0020] The cover glass 11 is disk-shaped and includes 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.

[0021] The low-melting glass 9 is bismuth- or tellurium-based low-melting glass formed into a ring-shaped tablet before sealing (see FIG. 2). As described later, the low-melting glass 9 becomes molten 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. Furthermore, the low-melting glass 9 may be other than the above-mentioned bismuth- or tellurium-based glass, and powder glass may be formed into a tablet, or a paste may be applied.

[0022] The following describes the manufacture and assembly of the protective cover 5. First, the cap 6 will be described with reference to FIG.

[0023] First, a cylindrical punch is pressed against a metal sheet of uniform thickness placed on a base several times by a press machine to form thin-walled portion 62A, thick-walled portion 62B that is thicker than thin-walled portion 62A, and ceiling 16. Also, window 8 is formed in ceiling 16 by drilling. In this manner, cap 6 is manufactured as shown in FIG. 2.

[0024] 2, 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), heated to 500° C. in a nitrogen gas atmosphere, and held for 10 minutes in that state. The low-melting point glass 9 is melted, and the cover glass 11 is fused and sealed to the underside 16a of the ceiling 16 of the cap 6.

[0025] Here, the fiber flow of the cap 66 manufactured by pressing shown in Fig. 4(a) and the fiber flow of the cap 6 of this embodiment manufactured by cutting shown in Fig. 4(b) will be described. The fiber flow refers to the flow of the fibrous metal structure that can be confirmed using a microscope or the like, and differs depending on the processing method. The cap 66 and the cap 6 have approximately the same shape.

[0026] 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 width 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 those of the cut cap 66. This makes it possible to maintain strength even when the thin-walled portion 62A is formed thin.

[0027] For reference, the fiber groves of the cap 66, which is machined from a cylindrical metal material, extend in the radial direction, approximately perpendicular to the axial direction in which the peripheral wall 66A rises, as shown in Fig. 4(b), and the widths between adjacent fiber groves at the peripheral wall 66A and the ceiling 66B are approximately uniform and long. Furthermore, the length from the starting end to the terminal end of each fiber grove is short.

[0028] Furthermore, 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 applied to the optical device 1. The peripheral wall 62 of the cap 6 of the present invention has a thick portion 62B arranged in the circumferential direction on the window 8 side, so that the rigidity of the window 8 side of the cap 6 is increased, 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.

[0029] In addition, as shown in FIG. 3, since the thickness from the outer peripheral surface to the inner peripheral surface of thick-walled portion 62B is sufficiently large, it is possible to secure region H as a highly rigid flat surface consisting of the upper surface of ceiling 16 and the upper surface of thick-walled portion 62B, making it easy to perform welding, etc., in region H.

[0030] In addition, the fiber flow in region H is continuous with the peripheral wall 62 extending in the axial direction, bent at approximately 90 degrees, and extends in the inner diameter direction, so that the cap 6 is less likely to deform and the orthogonality of the light emission / incidence between the cover glass 11 and the optical device element 2 is maintained (see Figure 4(a)).

[0031] In this manner, the protective cover 5 includes the cap 6 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 connected to the thin portion 62A and disposed on the window 8 side, so that the orthogonality between the cover glass 11 and the light emission / incoming can be maintained and a sufficient space can be secured to accommodate 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.

[0032] Furthermore, since the thick portion 62B and the thin portion 62A are formed to have substantially the same outer diameter, the cap 6 can be formed compactly without being bulky in the width direction while ensuring a space for accommodating the optical device element 2.

[0033] Furthermore, since the ceiling 16 is formed thinner than the thick portion 62B, the weight of the upper portion of the cap 6 can be reduced, so that 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 or the like.

[0034] Furthermore, since the ceiling 16 is formed by pressing, a thin, smooth surface can be prepared at low cost.

[0035] Furthermore, since the cap 6 is molded from a single piece of material with a uniform thickness, the cap 6 is molded as a single piece, ensuring strength.

[0036] 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.

[0037] For example, in the above embodiment, an Fe-Ni alloy is used as the material of 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.

[0038] In addition, in the above embodiment, a form in which a disk-shaped cover glass 11 is attached to the window 8 is exemplified, but the present invention is not limited to this. For example, a spherical lens, an aspherical lens, or a fused lens may be attached.

[0039] In addition, in the above embodiment, a form in which a flange portion 63 is formed at the lower end of the peripheral wall 62 of the cap 6 is exemplified, but the present invention is not limited to this, and the cap may be a bottomed cylindrical body in which the flange portion is omitted.

[0040] In addition, in the above embodiment, the outer diameters of the thin-walled portion 62A and the thick-walled portion 62B are formed to be approximately the same, but the present invention is not limited to this, and the cap 6 may be configured such that the inner diameters of the thin-walled portion 62A and the thick-walled portion 62B are approximately the same but the outer diameters are different.

[0041] In addition, in the above embodiment, the window 8 is illustrated as being formed in a circular shape, but the present invention is not limited to this, and the window 8 may be formed in a shape other than a circle, such as a square, polygonal, or elliptical shape.

[0042] In addition, in the above embodiment, the cap 6 is illustrated as being formed in a circular shape when viewed from above, but the present invention is not limited to this, and the cap 6 may be formed in a shape other than a circular shape when viewed from above, such as a square shape, a polygonal shape, or an elliptical shape when viewed from above.

[0043] 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.

[0044] In addition, in the above embodiment, the peripheral wall 62 is exemplified as being 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 a peripheral wall having three or more different thicknesses.

[0045] In addition, in the above embodiment, the ceiling 16 is exemplified as being formed by press working so that it is approximately perpendicular to the peripheral wall 62, but the present invention is not limited to this, and after the ceiling 16 and the peripheral wall 62 are formed by press working, the ceiling 16 may be bent so that it is approximately perpendicular to the peripheral wall 62. [Explanation of symbols]

[0046] 1. Optical Devices 2. Optical device elements (optical elements) 3. Stem 4 Terminals 5 Protective cover 6 Cap 8. Windows 9. Low-melting glass 11 Cover glass (amorphous or crystalline) 16 Ceiling 62 Peripheral wall 62A Thin section 62B Thick wall part 63 Flange

Claims

1. 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 is disposed on the window side; The ceiling is a protective cover formed to be thinner than the thick portion.

2. 2. The protective cover according to claim 1, wherein the thin-walled portion and the thick-walled portion have substantially the same outer diameter.

3. 3. The protective cover according to claim 1, wherein the ceiling is formed by pressing.

4. 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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