JPS6234457Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a photodetecting semiconductor device that completely eliminates the influence of ambient light and improves light conversion efficiency.

A photodetector semiconductor device (hereinafter referred to as a photointerrupter) that combines a visible light and near-infrared monochromatic light-emitting element with a highly sensitive light-receiving element and is covered with an envelope is capable of combining logic circuits, position detection, timing detection, and rotation. Widely used for speed detection, photoelectric switches, etc. Here, the structure of a conventional photointerrupter is shown in FIG. In Figure 1, figure A is a perspective view, figure B is a perspective view, and figure B is a perspective view.
1 is a cross-sectional view, and C is a perspective view showing a translucent epoxy resin covering the light-emitting element or the light-receiving element.
As shown in FIG. 1A, the photointerrupter has an envelope 11 made of a material that does not transmit light and has two tubes 11a and 11b. The cylinder 11a
and 11b each have a space inside, and the cylinder 11
A light emitting element is incorporated in a, and a light receiving element is incorporated in the cylinder 11b. Further, slits 12 are provided on the opposing surfaces of the tubes 11a and 11b, respectively, so that light emitted from the light emitting element in the tube 11a is incident on the light receiving element in the tube 11b. Further, in FIG. 1B, reference numeral 13 denotes a gallium phosphide or gallium arsenide pellet as a visible light and near-infrared monochromatic light emitting element, and an electric signal is inputted to the pellet via a lead frame 14. Further, a tube 15a made of a translucent epoxy resin is provided inside the tube 11a. In addition, 16 is a silicon pellet as a highly sensitive light receiving element.
An electrical signal is output from the pellet via the lead frame 17. Further, a tube 15b made of a translucent epoxy resin is provided inside the tube 11b. Further, Figure C is a perspective view of the tubes 15a and 15b, and the opposing surfaces of the tubes 15a and 15b have protrusions 18a and 18b, which serve as light guide paths.

FIG. 2 shows an example in which the photointerrupter shown in FIG. 1 is used to detect the rotational speed of, for example, a motor. In Figure A, 21 is a rotating shaft of a motor, and a rotary plate 22 having a shape as shown in Figure B is attached to this rotating shaft 21. The rotating plate 22 has sector-shaped through holes 23 and 2.
4 is provided. Therefore, when the rotating plate 22 rotates together with the rotating shaft 21, the light emitted from the light emitting element reaches the light receiving element 16 when the through hole 23 or 24 is interposed between the slits 12. Therefore, as the rotational speed of the rotating shaft 21 increases, the period of light reaching the light receiving element becomes shorter, and by detecting this, the rotational speed of the rotating shaft 21, that is, the motor, is detected.

However, in conventional photointerrupters, the light emitted from the light emitting element passes through the outside of the envelope 11 to reach the light emitting element, which has the disadvantage that ambient light enters the light receiving element, causing the photointerrupter to malfunction. . Furthermore, since the light emitted from the light emitting element is radiated outside the envelope 11, there is a drawback that the light escapes to others and the light conversion efficiency is low. Furthermore, smoke or dust in the atmosphere enters the inside of the photointerrupter through the slit 12, causing the photointerrupter to malfunction and reducing its reliability.

This idea was made in view of the above points,
The aim is to provide a photodetecting semiconductor device that can completely eliminate the influence of ambient light and improve light conversion efficiency.

An embodiment of this invention will be described below with reference to the drawings. FIG. 3A is an external perspective view of the photointerrupter. In the same figure A, a non-transparent envelope 3
1 has a rotating rod 32 inserted therein. Further, a space in which a light emitting element and a light receiving element are installed is present in the envelope 31 in a direction perpendicular to the rotary rod 32 at positions facing each other with the rotary rod 32 interposed therebetween. Figure B shows envelopes 32a and 33 made of translucent epoxy resin and containing light-emitting elements or light-receiving elements incorporated in the space inside the envelope 31.
It is b. Then, each envelope 33a or 33
A lead wire 34 or 35 extends from b. FIG. 3C shows a cross section of FIG. 3A. In the figure, a space is provided in the envelope 31 to accommodate the envelopes 33a and 33b at a position perpendicular to the rotating shaft 32.
Optical path 36 that guides light emitted from the light emitting element in a
is provided. Further, the rotating shaft 32 is provided with a single through hole 37 perpendicular to the axial direction, and when the rotating rod 32 is in the position shown in FIG. and through hole 37
and reaches the light receiving element. In this state, the photointerrupter is turned on. However, when the rotating rod 32 rotates and the through hole 37 is in the position shown in FIG. do not. In this state, the photointerrupter is turned off. Therefore, the frequency at which the photointerrupter is turned on increases in proportion to the speed at which the rotary rod 32 rotates, and this is detected to obtain the rotation speed.

Figure 4 shows another embodiment of this invention.
Figure A is a perspective view, and Figure B is a sectional view. In FIG. 4A, reference numeral 41 denotes a non-light-transmitting envelope, into which a rotating rod 42 is inserted. An optical path 43 is provided in the envelope 41 in a direction perpendicular to the rotating rod 42 . An envelope 44a in which a light emitting element is disposed and an envelope 44b in which a light receiving element is disposed are inserted into both ends of the optical path 43. The optical path 43 serves as an optical path for light emitted from the light emitting element, and as shown in FIG. 4B, the rotating rod 43
2, the light emitted from the light emitting element reaches the light receiving element via the optical path 43 and the through hole 45. In this state, the photointerrupter is turned on. In other words, the frequency at which the photointerrupter is turned on increases in proportion to the rotation speed of the rotating shaft 32, and this is detected to obtain the rotation speed.

Furthermore, another embodiment of this invention will be explained using FIG. 5. In the figure, reference numeral 51 denotes a non-transparent envelope, into which a rotating rod 52 is inserted. This rotary rod 52 has a through hole 53 perpendicular to the axial direction.
1 to 534 are consecutively provided. Further, each through hole is arranged at a position 90 degrees out of phase with respect to the rotation direction. Also, 541 to 544
denotes an envelope in which a light receiving element is disposed, and each envelope is embedded in the envelope 51 at a predetermined interval. Also,
Reference numerals 551 to 554 designate envelopes in which the light receiving elements are disposed, and each envelope is embedded within the envelope 51 at a position facing the envelopes 541 to 544. Further, the light emitted from the light emitting elements in the envelopes 541 to 544 is transmitted to the light receiving elements in the envelopes 551 to 554 through through holes that are connected at a predetermined interval in a direction perpendicular to the rotary rod 52. reach. That is, as the rotary rod 52 rotates, electrical signals with different timings are obtained from the light receiving elements 551 to 554.

As detailed above, according to this invention, there is an optical path that guides the light emitted from the light emitting element embedded in the non-transparent envelope to the light receiving element, so the influence of ambient light is reduced. Malfunctions can be prevented without any problems.
Furthermore, since the light passing through the optical path does not escape to the outside, the light conversion rate can be improved. In addition, because the light emitting element, the light receiving element, and the optical path that guides the light emitted from the light emitting element to the light receiving element are sealed in the envelope, there is no influence of external smoke, dust, dirt, etc., and the photo Interrupter reliability can be improved.

[Brief explanation of the drawing]

Figures 1 and 2 are views showing conventional examples, respectively. Figure 1A is a perspective view, Figure 1B is a sectional view, and Figure 1B is a sectional view.
Figure C is a perspective view, Figure 2A is a side view, Figure 2B is a plan view of the rotating plate, and Figure 3 shows an embodiment of this invention. 4 is a perspective view, C and D are sectional views, and FIG. 4 shows another embodiment of this invention. FIG. 4A is a perspective view, B is a sectional view, and FIG. FIG. 7 is an exploded perspective view showing another embodiment. 31... Envelope, 32... Rotating rod, 33a, 3
3b... Envelope, 34, 35... Lead wire.

Claims (1)

[Scope of utility model registration request] A light-emitting element and a light-receiving element are embedded opposite each other in a non-transparent envelope, an optical path is provided between the light-emitting element and the light-receiving element, and an optical path is provided between the elements so as to block the optical path. What is claimed is: 1. A photodetecting semiconductor device comprising: a rotary rod rotatably provided in an envelope portion of the semiconductor device and having a through hole partially communicating with the optical path.