JPH10302587A - Optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct proper detection always by setting the light spot size of reflection light and the beam width (a spot diameter) of an irradiation ray in an optical sensor detecting the existence of a person and the like. SOLUTION: An LED(light emitting diode) 2, a condenser lens 4 which condenses light from the LED 2, a PD(photo diode) 3 receiving reflection light which is from a body to be detected and passes through the condenser lens 4, and an image focusing lens 5 which image focuses the reflection light on the PD 3 are arranged in a case 1. Thread grooves 4a, 5a are provided on the outer peripheries of the respective lens 4, 5, and simultaneously thread grooves 1a, 1b are provided on the lens hold portion of the case 1 so as to threadedly engaged with the thread grooves 4a, 5a so that positions of the LED 2 and the PD 3 against the respective lens 4, 5 can be easily adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor for detecting, for example, the presence of a person, and more particularly to an optical sensor for detecting reflected light from an object to be detected.

[0002]

2. Description of the Related Art Conventionally, as this type of optical sensor, for example, one shown in FIG. 4 is known. FIG. 4 is a sectional view showing a schematic configuration thereof.

In this sensor, an LED (light emitting diode) 2 and a PD (photodiode) 3 are fixed to one end side (bottom) inside a case 1 with a partitioning plate interposed therebetween, and light is condensed at a predetermined distance from these. The lens 4 and the imaging lens 5 are arranged, and each of the lenses 4 and 5 is fixed between the side wall of the case 1 and the partition plate.

In the sensor having the above-described structure, light from the LED 2 irradiates the object to be detected through the lens 4, and light reflected by the object is guided to the PD 3 through the lens 5. Therefore, the presence or absence of the detection target can be detected by measuring the output of PD3.

Here, the height of the lenses 4 and 5 (the distance between the elements 2 and 3) cannot be adjusted, and the quality of the product depends on the dimensional accuracy of the case 1 and the lenses 4 and 5. Will be determined.

That is, P due to light reflected from the object to be detected
The light spot on D3 changes according to the height of the lens 5 as shown in FIG. 2, and when the image is formed correctly, the light spot has a predetermined size like the light spot S1 indicated by the solid line. When the image is blurred, the light spot S2 becomes larger as indicated by a broken light spot S2.

The light beam width of the light from the LED 2, that is, the diameter of the light spot on the object to be detected, which is a reflection object, also varies depending on the height of the lens 4, as shown in FIG. At this time, the light beam has a predetermined width (diameter) as indicated by the solid line light beam 1L. When the light beam is not condensed correctly and spreads and is irradiated, the light beam becomes large as indicated by the broken line light beam L2.

[0008]

Since the conventional optical sensor is configured as described above and cannot adjust the height of the lens (focus adjustment), the light spot of the reflected light spreads depending on the position of the lens, resulting in blurring. In addition, there has been a problem that a predetermined light beam width (spot diameter) at which the irradiation light becomes parallel light cannot be obtained, and proper detection cannot be performed.

The present invention has been made in view of the above-mentioned problems, and the size of the light spot of the reflected light and the light beam width (spot diameter) of the irradiation light can be set correctly, so that it is always appropriate. It is an object of the present invention to provide an optical sensor capable of performing accurate detection.

[0010]

SUMMARY OF THE INVENTION An optical sensor according to the present invention comprises a light emitting element, a condensing lens for condensing light from the light emitting element, and an object to be detected passing through the condensing lens. A light receiving element for receiving the reflected light from the body, and an imaging lens for forming an image of the reflected light on the light receiving element; and a position of the condensing lens with respect to the light emitting element and an image forming for the light receiving element. Adjusting means for adjusting the position of the lens.

The adjusting means comprises a screw groove provided on an outer peripheral portion of each lens and a screw groove provided on a lens holding portion of the case so as to be screwed into the screw groove. The light receiving element is a photodiode.

[0012]

FIG. 1 is a sectional view showing a schematic configuration of an optical sensor according to the present invention, and the same reference numerals as those in FIG. 4 denote the same components.

In FIG. 1, reference numeral 1 denotes a case, and reference numerals 2 and 3 denote an LED (light emitting element) and a PD (light receiving element) arranged below the case 1, which are shielded from each other by a partition plate.
Reference numeral 4 denotes a condensing lens for condensing light from the LED 2, and a screw groove 4 a provided on an outer peripheral portion is screwed with a screw groove 1 a provided on a lens holding portion of the case 1.
The position (height) with respect to the ED 2 is configured to be adjustable. Reference numeral 5 denotes an image forming lens for forming an image of the reflected light from the detection object passing through the condensing lens 4 on the PD 3, and a screw groove 5 a provided on the outer peripheral portion of the case 1 like the condensing lens 4.
Is screwed into the thread groove 1b provided in the lens holding portion of the camera, and the position (height) with respect to the PD 3 can be adjusted.

FIG. 2 shows a single unit of each of the lenses 4 and 5. As shown, screw grooves 4a and 5a are provided on the outer periphery other than the lens surface through which light passes, so that the height position can be easily adjusted. FIG. 3 is a perspective view showing the shape of the case 1 from which the lenses 4 and 5 have been removed.

In the optical sensor having the above-described structure, similarly to the sensor shown in FIG. 4, light from the LED 2 is applied to the object through the lens 4 and reflected light from the object is guided to the PD 3 through the lens 5. The presence or absence of the object to be detected is detected from the output of PD3.

At this time, as described above, proper detection cannot be performed unless the heights of the lenses 4 and 5 are appropriate.
In the present embodiment, the means for adjusting the lens position is provided by the screw grooves 4a and 5a of the lenses 4 and 5 and the screw grooves 1a and 1b of the lens holding portion of the case 1 screwed thereto, so that the reflected light can be easily formed. The size of the light spot and the beam width (spot diameter) of the irradiation light can be set correctly, and appropriate detection can always be performed.

That is, there are screw grooves on the side of the lens and the inside of the case, and the height of the lenses 4 and 5 can be easily changed by the principle of screws by a simple operation just by rotating the lenses 4 and 5. And the dimensional accuracy of the lenses 4 and 5 can be easily corrected. This precision depends only on the pitch of the thread groove, and the precision can be improved as required.

[0018]

As described above, according to the present invention, since the means for adjusting the position of each lens with respect to the light emitting element and the light receiving element is provided, the size of the light spot of the reflected light and the light width of the irradiation light (spot width) Diameter) can be set correctly,
There is an effect that appropriate detection can always be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an optical sensor according to the present invention.

FIG. 2 is a view showing the shape of each lens in FIG. 1;

FIG. 3 is a perspective view showing the shape of the case of FIG. 1;

FIG. 4 is a cross-sectional view showing a schematic configuration of a conventional optical sensor.

FIG. 5 is an explanatory diagram showing a light spot on a PD in FIG. 4;

FIG. 6 is an explanatory diagram showing light rays from the LED of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 1a Screw groove 1b Screw groove 2 LED (light emitting element) 3 PD (light receiving element) 4 Condensing lens 4a Screw groove 5 Imaging lens 5a Screw groove

Claims (3)

[Claims] A light-emitting element; a condensing lens for condensing light from the light-emitting element; a light-receiving element for receiving reflected light from an object passing through the condensing lens; An image forming lens for forming an image of the reflected light on the light receiving element, and adjusting means for adjusting the position of the condensing lens with respect to the light emitting element and the position of the image forming lens with respect to the light receiving element. An optical sensor characterized in that: 2. The adjusting means comprises a screw groove provided on an outer peripheral portion of each lens, and a screw groove provided on a lens holding portion of the case so as to be screwed into the screw groove.
An optical sensor as described in the above. 3. The light emitting device according to claim 1, wherein the light emitting device is a light emitting diode, and the light receiving device is a photodiode.
Or the optical sensor according to 2.