JPH0326773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is an optical detection device with easy sensitivity adjustment, and is particularly suitable for detecting ambient brightness in an automobile.

[Conventional technology]

Conventionally, this type of sensitivity adjustment mechanism has a light-transmitting part between an optical system that collects light from a light source and a light receiving element, such as the photoelectric switch shown in Japanese Utility Model Application Publication No. 53-158880. There is a device in which a disc-shaped mask is movably supported approximately in the direction of the optical axis, and by moving the position of the mask, the amount of light incident on the light-receiving element is controlled and the sensitivity of the light-receiving element is adjusted.
This allows you to raise or lower the sensitivity without making any changes to the electrical circuit.

[Problem to be solved by the invention]

However, since this conventional example adjusts the optical axis between the light emitting part (light source) and the light receiving part (light receiving element), an optical system that condenses the light from the light source is considered essential. However, such an optical system is generally not necessary when the object to be detected is a uniform light source such as the sky and the surrounding brightness is to be detected.

In this case, the direction of the light incident on the light receiving element varies, and if you want the incident light to come from a specific direction, especially if you want to avoid being affected by the incident light from an oblique direction, the above-mentioned conventional The disk-shaped mask shown in the example has a problem in that the farther the mask is from the light receiving element, the more susceptible it is to the effects.

Also, in order to avoid being affected by incident light from an oblique direction, it is possible to make the disk-shaped mask thicker, but the thicker the mask, the narrower the range of light receiving sensitivity that can be detected. As a result, there is a problem that the adjustable sensitivity range becomes narrow.

The present invention has been made in view of the above-mentioned problems, and is intended to prevent an optical detection device that does not have an optical system for condensing light from a light source from being affected by incident light from directions other than a specific direction. It is possible,
Another object of the present invention is to provide an optical detection device that can adjust the light receiving sensitivity over a wider range.

[Means to solve the problem]

In order to achieve the above object, an optical detection device according to the present invention includes: a base body; a light receiving element supported by the base body and placed in an atmosphere of a uniform light source; a cylindrical body disposed with a transmitting part and supported such that the distance between the light receiving element and the base body changes in the front direction of the light receiving element, the cylindrical body , has a predetermined thickness in the front direction so that the light source from the front direction selectively enters the light receiving element through the light transmission section, and the predetermined shape of the light transmission section. adopts a technical means in which the cylindrical body has a shape in which the light transmission area gradually decreases toward the light receiving element in the thickness direction.

[Action and effect]

That is, in the above configuration, the distance between the cylinder and the light-receiving element changes by moving the cylinder provided with the light-transmitting part relative to the base in the front direction of the light-receiving element.

At this time, since the cylindrical body has a predetermined thickness in the front direction, the amount of light that enters the light receiving element through the light transmitting portion is almost the same as the light that enters from the front direction, i.e. The amount of light is adjusted to be determined by the solid angle when viewing the light transmitting section from the light receiving element.

At this time, since the shape of the light transmitting part has a shape in which the light transmitting area gradually decreases toward the light receiving element in the thickness direction of the cylindrical body, from the light receiving element to the light transmitting part When the cylinder moves and approaches the light-receiving element, the light transmission area increases, so the amount of light incident on the light-reception element increases; conversely, as the cylinder moves away from the light-receiving element, the light transmission area increases. becomes small, the solid angle becomes small accordingly, and the amount of light incident on the light receiving element becomes small.

In this way, by moving the cylinder relative to the substrate, the light transmission area changes according to the predetermined shape of the light transmission section, and the amount of light incident on the light receiving element is adjusted.

Further, the range of the amount of light incident on the light receiving element can be set wider depending on the predetermined shape of the light transmitting portion.

As described above, according to the present invention, it is possible to prevent the influence of incident light from a direction other than a specific direction without having an optical system, and the light receiving sensitivity can be adjusted over a wider range. The effect is produced.

〔Example〕

The present invention will be described below with reference to embodiments shown in the accompanying drawings. FIG. 1 is a sectional view of an optical detection device according to an embodiment of the present invention, and FIG. 2 is an explanatory assembly diagram showing individual components of this optical detection device.

In FIGS. 1 and 2, 1 is a filter made of optically transparent resin or glass;
2 is a housing that serves as a base when the whole is assembled; 3 is a cover that houses each element of the adjustment mechanism; 4 is an annular body (ring) that is rotated during adjustment.
It is. A through hole 12 is provided in the housing 2 so that the ring 4 can be rotated from the outside, and a groove 3b is formed in the cover 3 for the same purpose. A female thread 4b is formed on the inside of the ring 4, and serrations are formed on the outside for convenient rotation. Downward protrusion 1 of filter 1
a has the role of preventing the ring 4 from moving up and down.

Reference numeral 5 denotes a cylindrical body (cylinder) in which a cone-shaped light transmitting portion 5b is formed, and a male thread 5c is formed on the outer periphery of the cylinder, which is adapted to mesh with a female thread 4b.
A groove 5a extending in the axial direction is formed in the cylinder 5, and this groove 5a forms a protrusion 3a formed in the cover 3.
By loosely fitting the cylinder 5 to the ring 4,
This prevents them from rotating together.

6 is a hybrid IC board as a circuit part, on which an amplifier circuit and other circuit parts are mounted.
Reference numeral 7 denotes a photodiode 7 as a light receiving element arranged on the hybrid IC 6. 6a is a lead pin for making an electrical connection between the hybrid IC 6 and the outside; 8 is a terminal to be connected to the lead pin 6a by soldering; 9 is a terminal holder; 1
0 is a lead wire connected to the terminal 8 within the terminal holder 9, and 11 is a back cover.

Here, filter 1, housing 2, cover 3, hybrid IC 6, holder 9 and back cover 1
1 are fixed to each other by adhesive. Furthermore, the housing 2, cover 3, ring 4, cylinder 5, holder 9, and back cover 11 are made of resin.

In the above configuration, referring to FIG. 1, the cylinder 5 is located at the lowest position and is closest to the light receiving element 7. At this time, the light-receiving range of the light-receiving element 7 is represented by a solid angle a defined by the widened upper end of the conical light-transmitting portion 5b of the cylinder 5.

When the ring 4 is rotated with a thin screwdriver or the like through the through hole 12 provided in the housing 2 and the groove 3b provided in the cover 3, the ring 4 rotates at a position sandwiched between the cover 3 and the protrusion 1a of the filter 1. . The cylinder 5 does not rotate due to the action of the groove 5a and the projection 3a, but is displaced in the axial direction by a distance corresponding to each rotation of the ring 4. In other words, the distance between the conical light transmitting portion 5b and the light receiving element 7 increases.

Assuming that the cylinder 5 has now moved to the position shown by the broken line in FIG. 1, the light receiving range of the light receiving element 7 becomes a solid angle indicated by b defined by the narrowed lower end of the conical light transmitting portion 5b.

If the object to be detected by this optical detection device is a uniform surface light source such as the sky, the amount of light received by the light receiving element 7 is proportional to the solid angle. Therefore, the solid angle a
The detection sensitivity when the ring 4 has a solid angle b is better than that when the solid angle b
can be arbitrarily selected from a continuous range depending on the rotation angle of. It goes without saying that by setting the pitch of the threads between the ring 4 and the cylinder 5, the adjustment range of the sensitivity to the rotation angle of the ring 4 can be arbitrarily selected.

Furthermore, since the cylinder 5 is thick in the movable direction, the thickness can block incident light from an oblique direction, especially when the cylinder 5 moves to the position shown by the broken line in FIG. The amount of light incident on the light-receiving element 7 can be limited to the amount determined by the solid angle b.

Note that the screw 4 of the ring 4 in the above embodiment
b and the screw 5c of the cylinder 5 may be modified such as the relationship between the protrusion 4c and the screw 5c shown in FIG. 3, or the relationship between the protrusion 4d and the spiral groove 5b shown in FIG.

In addition, the shape and material of each component can be changed and selected as necessary, and the fixing means is not limited to adhesive, as shown in FIG.
a, 13a, 14a and recesses 12b, 12b, 12
It may be fixed by fitting with c.

For example, the cylinder 5, which is a cylindrical body, is not completely cylindrical, and may have a shape in which a portion, for example, the groove 5a, is completely cut off.

The light transmitting portion 5b of the cylinder 5 may be made of resin or glass that is transparent to light.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an explanatory assembly diagram showing its constituent parts, and FIGS. 3, 4, and 5 are assembly explanatory diagrams showing the above-mentioned modification. 1... Filter, 2... Housing (base body),
3...Cover, 4...Ring (annular body), 4a...
...Female thread, 5...Cylinder, 5c...Male thread, 7
……Light receiving element.

Claims (1)

[Scope of Claims] 1: a base; a light-receiving element supported by the base and placed under a uniform light source atmosphere; a light-transmitting part of a predetermined shape provided on the front surface of the light-receiving element; a cylindrical body supported such that the distance between the light receiving element and the base body changes in the front direction of the light receiving element, and the cylindrical body selects the light source from the front direction. The light transmitting part has a predetermined thickness in the front direction so that the light enters the light receiving element through the light transmitting part, and the predetermined shape of the light transmitting part has a predetermined thickness in the thickness direction of the cylindrical body. An optical detection device characterized in that the optical detection device has a shape in which a light transmission area gradually decreases toward the light receiving element.