JP2011124492A - Optical package and photoelectric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical package and a photoelectric sensor that easily reduce stray light at low cost. <P>SOLUTION: The optical package includes a projection element 1 which is installed on a mount substrate 2 and powered to emit light, a metal package 3 which is installed on the mount substrate 2 and accommodates the projection element 1 therein, an opening 4 for emitting light emitted by the projection element 1 to the outside, and a coating surface 9 for absorbing the stray light by painting an inner peripheral surface of the metal package 3 in black. The photoelectric sensor uses, as a projection beam, the light of the projection element 1 emitted from the opening 4 of the optical package. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical package with reduced stray light and a photoelectric sensor using the optical package.

  7A and 7B show a configuration of a conventional optical package. FIG. 7A is a plan view and FIG. 7B is a front view (partial cross-sectional view). In FIG. 7, a light projecting element 1 such as a light emitting diode is mounted on a mount substrate 2 and accommodated in a metal package 3. The gap between the metal package 3 and the light projecting element 1 may be sealed with a translucent resin. An opening 4 is formed on the upper surface of the cylindrical metal package 3, and a lead wire 5 for mounting on the circuit board is connected to the lower surface of the mount substrate 2. The light projecting element 1 and the lead wire 5 are connected by the electrodes 6, 7 and the electrode line 8, and the light projecting element 1 emits light when energized. The light emitted from the light projecting element 1 is projected upward from the opening 4 in FIG. 7B, but a part of the light is internally reflected by the inner surface of the outer wall of the metal package 3 and is indicated by an arrow in the figure. It becomes stray light.

  FIG. 8 is a diagram showing a beam pattern of a photoelectric sensor using the conventional optical package shown in FIG. The photoelectric sensor projects the light of the light projecting element 1 emitted from the opening 4 into a detection beam through a light projecting lens installed on the opening 4 to the detection area. In the example of FIG. 8, the light projection beam A (square surface shape) of the light projecting element 1 is the brightest region among the beam patterns of the photoelectric sensor. Internally reflected light appears as annular stray light B around it. Then, the output operation of the photoelectric sensor may become unstable due to stray light B generated in the detection region. In addition, a disc-shaped insensitive zone C darker than the projection beam A appears at the center of the projection beam A because the light emitted from the projection element 1 is blocked by the electrode 6. The shadow of not only the electrode 6 but also the electrode line 8 may appear.

  Such stray light B is generated not only in the metal package 3 but also in a resin mold package, for example. FIG. 9 is a front view showing a configuration of an optical package in which the light projecting element 1 is sealed with a resin mold package 10. Even in this configuration, light is reflected to some extent on the inner peripheral surface of the resin mold package 10 due to the difference in refractive index between air and resin, so that stray light appears in the beam pattern of the photoelectric sensor.

  FIG. 10 is a diagram showing a beam pattern of a conventional rectangular parallelepiped optical package. In FIG. 10A, light from a light projecting element (not shown) installed in a rectangular parallelepiped optical package 11 passes through a light projecting lens 12 installed at a distance d [mm] away from a light projecting beam. And is projected onto the detection region 13 installed at a position 200 mm away. FIGS. 10B to 10I show beam patterns that appear in the detection region 13 when the distance d between the optical package 11 and the projection lens 12 is variable from 7.0 to 7.7 mm in this configuration. 10B to 10I, the light projection beam A is the brightest region, and stray light B appears around it. Further, in FIG. 10H, a dead zone C appears at the center of the projection beam A. As described above, although the shape of the beam pattern changes depending on the distance d, stray light other than the image formation of the light projecting element is generated in any case. Although not shown, the shape of the beam pattern changes depending on the shape of the projection lens 12 as well as the distance d. Even in that case, stray light is generated.

  Thus, for example, in the photoelectric conversion device disclosed in Patent Document 1, a light shielding plate is attached so as to cover the gap between the light projecting element and the inner peripheral surface of the metal package, thereby blocking the reflected light on the inner surface, thereby preventing the generation of stray light. It was.

JP 2004-31560 A

  Since the conventional optical package is configured as described above, in order to prevent stray light, a member that structurally blocks stray light, such as a light shielding plate, must be provided, which increases the cost. It was.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical package and a photoelectric sensor that can easily reduce stray light at low cost.

  An optical package according to a first aspect of the present invention is a light projecting element that is installed on a substrate and emits light when energized, a package that is installed on the substrate and accommodates the light projecting element, and a light that the light projecting element emits light. Is provided with an opening of the package and a painted surface on which the inner surface of the package is painted.

  An optical package according to a second aspect of the present invention is a light emitting element that is installed on a substrate and emits light when energized, a resin mold package that encapsulates the light emitting element on the substrate, and light emitted by the light projecting element. Is provided with an opening of the resin mold package and a painted surface on which the outer surface of the resin mold package is painted.

  An optical package according to a third aspect of the present invention is a light projecting element that is installed on a substrate and emits light when energized, a package that is installed on the substrate and accommodates the light projecting element, and light emitted from the light projecting element. Is provided with an opening portion of the package and a rough surface obtained by roughening the inner surface of the package.

  An optical package according to a fourth aspect of the present invention is a light emitting element that is installed on a substrate and emits light when energized, a resin mold package that encapsulates the light emitting element on the substrate, and light emitted by the light projecting element. Are provided with an opening of the resin mold package and a rough surface obtained by roughening the outer surface of the resin mold package.

  A photoelectric sensor according to a fifth aspect of the invention includes the optical package, and uses light emitted from an opening of the optical package as a projection beam.

  According to the invention of claim 1 or claim 2, since the inner surface of the package or the outer surface of the resin mold package is provided with a painted surface, the stray light of the light projecting element can be absorbed by the painted surface, An optical package that can easily reduce stray light at low cost can be provided.

  According to the invention of claim 3 or claim 4, since the inner surface of the package or the outer surface of the resin mold package is provided with a roughened surface, the stray light of the light projecting element is diffusely reflected by the rough surface. Thus, it is possible to provide an optical package that can easily reduce stray light at low cost.

  According to invention of Claim 5, since it was set as the photoelectric sensor provided with the said optical package, the photoelectric sensor which reduced the stray light easily at low cost can be provided.

The structure of the optical package which concerns on Embodiment 1 of this invention is shown, Fig.1 (a) is a top view, FIG.1 (b) is a front view. It is a figure which shows the beam pattern of the photoelectric sensor using the optical package shown in FIG. The optical package of the resin mold package 10 which concerns on Embodiment 1 of this invention is shown, Fig.3 (a) is a top view, FIG.3 (b) is a front view. It is a front view which shows the modification of the optical package which concerns on Embodiment 1 of this invention, and the electrode 6 is provided in two places on a diagonal line. It is a figure which shows the beam pattern of the photoelectric sensor using the optical package shown in FIG. It is a front view which shows the other structural example of the optical package which concerns on Embodiment 1 of this invention, FIG.6 (a) is the case where the resin mold package 10 is trapezoid shape, FIG.6 (b) is a hemispherical shape, FIG. 6C shows a mountain shape. The structure of the conventional optical package is shown, Fig.7 (a) is a top view, FIG.7 (b) is a front view. It is a figure which shows the beam pattern of the photoelectric sensor using the conventional optical package shown in FIG. It is a front view which shows the structure of the conventional optical package, and the case of the resin mold package 10 is shown. It is a figure which shows the beam pattern of the conventional rectangular parallelepiped optical package, The structure for beam pattern observation is shown to Fig.10 (a), and the beam pattern in the detection area 13 is shown to FIG.10 (b)-(i). .

Embodiment 1 FIG.
1A and 1B show a configuration of an optical package according to Embodiment 1 of the present invention. FIG. 1A is a plan view and FIG. 1B is a front view. In the optical package shown in FIG. 1, the same or corresponding parts as those of the conventional optical package shown in FIG.
The optical package shown in FIG. 1 is newly provided with a painted surface 9 in which a black paint is painted on the inner peripheral surface of the metal package 3. Since the painted surface 9 absorbs light emitted from the light projecting element 1 toward the inner surface of the outer wall of the metal package 3, internal reflection does not occur. Therefore, no stray light is generated. Further, since it is not necessary to separately provide a member for blocking stray light, stray light can be easily prevented at low cost. Further, after providing the painted surface 9, the metal package 3 may be sealed with a permeable resin.

FIG. 2 is a diagram showing an example of a beam pattern of a photoelectric sensor using the optical package shown in FIG. 1, and the same or corresponding parts as those in FIG. If the light projected from the opening 4 of the optical package shown in FIG. 1 is used as the light projection beam of the photoelectric sensor, the light projection beam A and the insensitive band C appear in the beam pattern as shown in FIG. (Ie, internally reflected light) does not appear.
However, as previously described with reference to FIG. 10, also in the case of the photoelectric sensor according to the first embodiment, the shape of the beam pattern is the distance between the light projecting element 1 and the light projecting lens (not shown), and the light projecting. It varies depending on the shape of the lens. In addition, the shadow of the electrode line 8 may appear in the beam pattern. An example of variously changing beam patterns is shown in FIG. 2, but stray light can be prevented by providing the painted surface 9 even if the shape of the beam pattern changes.

  In addition, you may shape | mold the package of the same shape as the metal metal package 3, for example using resin other than a metal. Also in the case of this configuration, a painted surface 9 is provided by painting a black paint on the inner peripheral surface of the resin package. Further, the resin package may be sealed with a translucent resin.

  Or the coating surface 9 can also be provided in the resin mold package which sealed the light projection element 1 inside. 3A and 3B show the configuration of the optical package of the resin mold package 10, FIG. 3A is a plan view, and FIG. 3B is a front view (partial sectional view). In the case of the resin mold package 10, the outer peripheral surface of the cylindrical resin mold package 10 is painted with a black paint to provide a painted surface 9, and the upper surface left unpainted is the opening 4. Even in this configuration, no internal reflection of the resin mold package 10 occurs, so that no stray light is generated.

Although the through-hole mounting type is illustrated as an example of the metal package 3 and the surface mounting type is illustrated as an example of the resin mold package 10, the metal package 3 may be configured as a surface mounting type or the resin mold package 10 Needless to say, may be configured as a through-hole mounting type.
Preferably, the surface mount type resin mold package 10 is an optical package having a configuration in which the inner peripheral surface of the package is perpendicular to the mount substrate 2. In the case of this configuration, the painted surface 9 is easy to paint and the internal reflection light is less likely to occur.

  Furthermore, the optical package used for the photoelectric sensor is preferably a surface-mount type resin mold package 10 as shown in FIG. 4, in which the electrode 6 is provided at the end instead of the center of the light projecting element 1. Good package. FIG. 4 shows an optical package having a configuration in which two electrodes 6 are provided on the upper diagonal of the light projecting element 1, and FIG. 5 shows an example of a beam pattern of a photoelectric sensor using this optical package. In the case of this configuration, since the insensitive zone C does not occur at the center of the projection beam A, the output operation of the photoelectric sensor becomes more stable. The shape of the beam pattern shown in FIG. 5 also varies depending on the shape of the projection lens, etc., as in FIGS. 2 and 8, but stray light can be prevented in either case.

As described above, according to the first embodiment, the light package is installed on the mount substrate 2 and emits light when energized, and the light projector 1 is installed on the mount substrate 2 and has the light projecting device 1 inside. The metal package 3 to be accommodated, the opening 4 for emitting light emitted from the light projecting element 1 to the outside, and the painted surface 9 in which the inner peripheral surface of the metal package 3 is painted black are provided. For this reason, stray light can be prevented by absorbing the inner surface reflected light reflected by the inner surface of the metal package 3 by the painted surface 9. Therefore, it is possible to provide an optical package that can easily reduce stray light at low cost.
Moreover, stray light can be easily reduced at low cost by applying this optical package to a photoelectric sensor and using the light of the light projecting element 1 emitted from the opening 4 of the optical package as a light projection beam. A photoelectric sensor can be provided.

  In the first embodiment, the cylindrical metal package 3 and the resin mold package 10 have been described as examples. However, the package shape is not limited to the cylindrical shape. FIG. 6 is a front view showing another configuration example of the optical package. When the resin mold package 10 has a trapezoidal shape as shown in FIG. 6A, for example, the trapezoidal side surface is the painted surface 9 and the upper surface is the opening 4. Further, when the resin mold package 10 has a hemispherical shape as shown in FIG. 6B, the mounting substrate 2 side of the hemispherical surface is the painted surface 9, and the opening 4 is directly above the light projecting element 1. To do. Further, in the case where the resin mold package 10 has a mountain shape as shown in FIG. 6C, the mount substrate 2 side of the mountain-shaped surface is the painted surface 9, and the opening 4 is directly above the light projecting element 1. To do. Note that the positional relationship and the area ratio between the painted surface 9 and the opening 4 may be appropriately determined according to the shape of the resin mold package 10 and the like.

  In the first embodiment, the painted surface 9 is formed by applying the black paint on the inner peripheral surface of the metal package 3 or the outer peripheral surface of the resin mold package 10, but the color of the paint is not limited to black. In addition, a paint having a color that can be easily absorbed in accordance with the emission color of the light projecting element 1 may be applied.

In the first embodiment, the coating surface 9 is formed on the inner peripheral surface of the metal package 3 (or resin package) or the outer peripheral surface of the resin mold package 10 to absorb stray light. However, the present invention is not limited to this. For example, instead of the painted surface 9, the surface may be roughened so that stray light is diffused and reflected to be scattered light. In this configuration, stray light on the beam pattern of the photoelectric sensor cannot be completely prevented, but the outline can be blurred and darkened as a whole. As a result, the output operation can be stabilized.
Furthermore, the coating surface 9 may be roughened to absorb and diffusely reflect stray light.

  Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific shape and structure of the package is not limited to the configuration of the above-described embodiment, and does not depart from the gist of the present invention. Needless to say, the present invention includes any design changes.

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Mount substrate 3 Metal package 4 Opening part 5 Lead wire 6,7 Electrode 8 Electrode line 9 Painted surface 10 Resin mold package 11 Rectangular-shaped light package 12 Light projection lens 13 Detection area A Light projection beam B Stray light C Insensitive zone

Claims (5)

A light emitting element installed on a substrate and emitting light when energized;
A package installed on the substrate and containing the light projecting element therein;
An opening of the package for emitting light emitted from the light projecting element to the outside;
An optical package comprising a painted surface on which an inner surface of the package is painted. A light emitting element installed on a substrate and emitting light when energized;
A resin mold package for sealing the light projecting element on the substrate inside;
An opening of the resin mold package that emits light emitted from the light projecting element to the outside;
An optical package comprising a painted surface on which an outer surface of the resin mold package is painted. A light emitting element installed on a substrate and emitting light when energized;
A package installed on the substrate and containing the light projecting element therein;
An opening of the package for emitting light emitted from the light projecting element to the outside;
An optical package comprising a rough surface obtained by roughening an inner surface of the package. A light emitting element installed on a substrate and emitting light when energized;
A resin mold package for sealing the light projecting element on the substrate inside;
An opening of the resin mold package that emits light emitted from the light projecting element to the outside;
An optical package comprising a rough surface obtained by roughening an outer surface of the resin mold package.   A photoelectric sensor comprising the optical package according to any one of claims 1 to 4, wherein light emitted from an opening of the optical package is used as a light projection beam.

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