JPH07273365A - Photo-sensor and assembling method thereof - Google Patents

Abstract

PURPOSE:To perform accurately the respective alignments of the optical axes of the light projecting and receiving lenses of a photo-sensor, by providing at least a pair of aligning holes in a printed circuit board, and by providing the aligning pins to be engagement-inserted into the aligning holes in the light projecting and receiving lenses of the photo-sensor. CONSTITUTION:In the state wherein aligning pins 45a, 45a of a lens base are engagement-inserted respectively into engagement-inserting holes 6a, 6a of an optical tube 6, the end parts of the aligning pins 45a, 45a are further engagement-inserted respectively into aligning holes 3a, 3a of a printed circuit board 3. Then, both the aligning pins 45a, 45a and the aligning holes 3a, 3a are used as refereces, and thereby, a light projecting element 1 and a light receiving element 2 can be provide respectively in one-opening parts of a pair of light guiding holes 6b, 6c provided in the optical tube 6, and a light projecting lens 4 and a light receiving lens 5 can be provided respectively in the other opening parts of a pair of light guiding holes 6b, 6c, while the respective alignments of the optical axes of the two lenses 4, 5 are performed. Therefore, since the aligning pins 45a, 45a are engagement-inserted directly into the respective aligning holes 3a, 3a, the respective alignments of the optical axes of the light projecting and receiving lenses 4, 5 are made possible simply and accurately.

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 an object and a method for assembling the optical sensor.

[0002]

2. Description of the Related Art Conventionally, there is an optical sensor of this type shown in FIG. This is a light projecting element A that inputs an electrical signal and emits light, a light projecting lens B that collimates the light emitted from the light projecting element A, and a light receiving device that collects the reflected light reflected by an object. Lens C and light-receiving element D that converts the incident light received from light-receiving lens C into an electrical signal and outputs it.
And an optical tube E having a pair of light guide holes E ₁ and E ₂ through which light passes.
And the light emitting element connected to the wiring part of the input / output electric signal
And a printed circuit board P on which the A and the light receiving element D are mounted.

More specifically, the optical tube E has a pair of light guide holes E ₁ and E ₂ with one opening E ₁₀ and E ₂₀ formed to match the outer shapes of the light projecting lens B and the light receiving lens C, and the other opening. The part E ₃₀ is formed by connecting both light guide holes so as to fit the outer shape of the printed circuit board P.

The light emitting element A and the light receiving element D are so-called discrete type, that is, the terminals led out from one side of the main body portion are inserted into the holes provided in the printed board P and then soldered to the wiring portion. The printed circuit board P is attached to the other opening E ₃₀ of the optical tube E, and the light projecting lens B and the light receiving lens C are respectively connected to the one opening E ₁₀ and E ₂₀ of the optical tube E. Be fitted.

[0005]

In the above-mentioned conventional optical sensor, the light projecting lens B and the light receiving lens C are formed in one opening of the pair of light guide holes E ₁ and E ₂ provided in the optical tube E. E ₁₀ , E ₂₀
, And the light emitting element A and the light receiving element D, respectively.
Are soldered to the wiring portions of the printed circuit board P through which electric signals are input and output, and then the printed circuit board P is fitted in the other opening E ₃₀ of the optical tube E.
The optical axes of the light projecting lens B and the light receiving lens C with respect to the light projecting element A and the light receiving element D are indirectly aligned via the optical tube E, and a pair of light guide holes E ₁ , E
_If the position of ₂ varies, it may not be accurate.

The light emitting element A and the light receiving element D are so-called discrete type in which terminals led out from one side of the main body are inserted into holes provided in the printed board P and then soldered to wiring portions. Therefore, in general, the height of the height including the terminals becomes high, and the entire photosensor becomes large.

To reduce the height of the back, the light emitting element A
Further, if the light receiving element D is a so-called surface mounting type (SMD type) that is surface-mounted by solder connection to the wiring portion printed on one surface of the printed board P, the height can be further reduced,
It is difficult to accurately position each element on the wiring part printed on one surface of the printed circuit board P, and the light-emitting element A and the light-receiving element D cannot be heated by the resin that forms the body part by sealing the elements themselves. Since it is weak, it cannot be soldered by reflow, which is generally performed when mounting an SMD type component, and automation is difficult, and it is necessary to mount by hand soldering.

The present invention has been made in view of the above circumstances. A first object of the present invention is to provide an optical system capable of easily and accurately aligning the optical axes of the light projecting lens and the light receiving lens with respect to the light projecting element and the light receiving element. A second object of the present invention is to provide an assembling method of a sensor and its optical sensor, and a second object is to provide an assembling method of an optical sensor capable of automatically mounting a light projecting element and a light receiving element on a printed circuit board.

[0009]

In order to solve the above-mentioned problems, according to a first aspect of the present invention, a light projecting element for inputting an electric signal to emit light and a light projecting from the light projecting element are parallel to each other. A light projecting lens for converting light, a light receiving lens for collecting reflected light reflected by an object, a light receiving element for converting incident light received from the light receiving lens into an electric signal and outputting the electric signal, and a pair of light guides through which the light passes. In an optical sensor including an optical tube having a hole and a printed board on which a light projecting element and a light receiving element are mounted by being connected to a wiring part for input / output electric signals, at least a pair of positioning holes are printed. Positioning pins that are provided on the substrate and that are inserted into the positioning holes are provided on the light projecting lens and the light receiving lens.

According to a second aspect of the present invention, in the first aspect, the positioning pin is provided on a supporting member of the optical fiber, and the light projecting lens and the light receiving lens have fitting insertion holes provided therein. It is arranged by being inserted into.

According to a third aspect of the present invention, the light, which is input from the light emitting element and emitted from the light emitting element and then becomes parallel by the light emitting lens, is reflected by an object and then condensed by the light receiving lens on the light receiving element. An optical sensor for detecting an object by converting it to an electric signal and outputting the electric signal, wherein the light sensor and the light receiving element are mounted on a printed circuit board by being connected to a wiring portion of the electric signal to be input and output. In the method, a light projecting element and a light receiving element are housed in a recess provided in a positioning jig, and a positioning pin at a predetermined position with respect to the recess is fitted into at least a pair of positioning holes provided in a printed circuit board to project the light. The optical element and the light receiving element are mounted on a printed circuit board.

According to a fourth aspect of the present invention, in the third aspect, the positioning jig has a through window through which the terminals of the light emitting element and the light receiving element can be seen, and the terminals are printed from the through window. It is designed to be soldered to the wiring part of the board.

According to a fifth aspect, in the fourth aspect, the terminal is soldered to the wiring portion of the printed circuit board by irradiating light from the through window.

[0014]

According to the first aspect of the present invention, the positioning pins provided on the light projecting lens and the light receiving lens serve as positioning means for at least one pair of printed circuit boards which serve as a reference for the wiring portion on which the light projecting element and the light receiving element are mounted. Since it is directly inserted into the hole, the optical axes of the light projecting lens and the light receiving lens can be easily and accurately aligned with the light projecting element and the light receiving element.

According to the second aspect of the present invention, when the optical fiber is connected to the light projecting lens and the light receiving lens, the positioning pin provided on the supporting member of the optical fiber is provided on the light projecting lens and the light receiving lens. The positioning pins are fitted into the fitting holes and integrally arranged, and the positioning pins are directly fitted into at least a pair of positioning holes provided on the printed board.

According to the third aspect of the invention, the light projecting element and the light receiving element are accommodated in the recess of the positioning jig and positioned, and the positioning pin at a predetermined position is printed in the recess. Since it is fitted into at least a pair of positioning holes provided in the board, it can be accurately mounted on the wiring portion of the printed board formed with the positioning holes as a reference.

According to another aspect of the present invention, as the light emitting element and the light receiving element, the terminals extend to both sides of the main body portion in plan view and are surface-mounted on the wiring portion of the printed circuit board.
A so-called SMD type is used, and in a state where the positioning jig is mounted on the printed circuit board, the terminal seen through the through window is soldered to the wiring portion of the printed circuit board.

According to the fifth aspect of the invention, by irradiating the terminal viewed through the through window with light, the solder is melted by the heat and the terminal is connected to the wiring portion of the printed board.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

Reference numeral 1 is a light projecting element, which is an element such as an LED (light emitting diode) which emits light by inputting an electric signal, and 2 is a light receiving element which receives incident light from a PSD (position detecting element) or the like. It is composed of an element for converting into an electric signal and outputting it, or an element including a processing circuit for processing the electric signal.

The light projecting element 1 and the light receiving element 2 are formed in a flat plate shape by sealing the elements themselves with a resin material so that light can be projected and received on the upper surface, and the terminals 1a and 2a are main bodies in plan view. It is so-called surface mount type (SMD type) so that it extends to both sides of the part and can be surface-mounted on the wiring part of the printed circuit board 3 which will be described later and protrudes slightly from the lower surface of the main body part.

3 is a printed circuit board, which is formed in a flat plate shape,
A pair of circular positioning holes 3a, 3a are penetrated at both ends, and wiring parts for electric signals input / output to / from the light emitting element 1 and the light receiving element 2 with reference to the positioning holes 3a, 3a are provided. It is formed of copper foil on one surface.

Denoted at 4 and 5 are a light projecting lens and a light receiving lens, which are made of a transparent material and are provided on both sides of the center of a flat lens base 45 so as to project in a convex shape at predetermined intervals.
A pair of positioning holes provided on the printed circuit board 3 at both ends of the
A pair of positioning pins 45a, 45a having the same pitch as the holes that can be fitted into the holes 3a, 3a are provided upright on the side opposite to the protruding direction of the lens.

Reference numeral 6 denotes an optical tube, which is formed of a molding material in a rectangular parallelepiped shape and has a pair of fitting pins having the same pitch as the pair of positioning pins 45a, 45a provided on the lens base 45 at both ends thereof. The insertion holes 6a, 6a are penetrated, and a pair of light guide holes 6b, 6c penetrating at the same intervals as the predetermined intervals of the light projecting lens 4 and the light receiving lens 5 are provided on both sides in the center in the thickness direction.

The above-mentioned members are assembled as follows. First, when the light projecting element 1 and the light receiving element 2 are mounted on the printed circuit board 3, the positioning jig 7 is used.

As shown in FIGS. 5 and 6, the positioning jig 7 is formed in a flat plate shape, and both ends of the positioning jig 7 can be fitted into the pair of positioning holes 3a, 3a provided in the printed circuit board 3. A pair of positioning pins 7a, 7a with the same pitch as that of the positioning pins 7a, 7a are erected on both sides of the center. Square recesses 7b, 7c that can accommodate the main body of 2 are formed in the standing direction of the positioning pins 7a, 7a, and through windows 7d, 7e are formed on both sides of the recesses 7b, 7c.
Are provided respectively.

Then, as shown in FIG.
Positioning pins 7a and 7a of 7 into the positioning holes of printed circuit board 3.
As shown in FIG. 4, when the light emitting element 1 and the light receiving element 2 are fitted into the recesses 7b and 7c, the terminals 1a and 2a can be seen through the through windows 7d and 7e. The printed circuit board 3 is positioned on the wiring part of the printed circuit board 3 in the closed state. Therefore, the terminals 1a, 2a are applied with a soldering iron from the through windows 7d, 7e,
The light emitting element 1 and the light receiving element 2 are surface-mounted on the printed circuit board 3 by being soldered to the wiring portion.

After that, the positioning jig 7 is attached to the printed circuit board 3
And the positioning pins 45a, 45a of the lens base 45 are fitted into the fitting holes 6a, 6a of the optical tube 6, and the tip ends of the positioning pins 45a, 45a are further positioned in the positioning holes 3a, 3a of the printed circuit board 3. When it is inserted into 3a, the positioning pins 45a, 45a and the positioning holes 3a, 3a serve as a reference, as shown in FIG.
The light projecting element 1 and the light receiving element 2 are arranged in one opening of the pair of light guide holes 6b, 6c provided in the optical tube 6, and the light projecting lens 4 and the light receiving lens 5 are respectively arranged in the other opening so that their optical axes are aligned. Is arranged.

The above-mentioned optical sensor detects an object by utilizing triangulation, and the light emitted from the light projecting element 1 must pass through the light guide hole 6b and enter the light projecting lens 4. It becomes a parallel light. This parallel light is reflected by an object at a predetermined distance and then enters the light receiving lens 5 to be condensed, passes through the light guide hole 6c, is focused on the light receiving element 2, and detects the object. is there.

In such an optical sensor, as described above, the light projecting element 1 and the light receiving element 2 are housed in the recesses 7b and 7c of the positioning jig 7 and positioned, and the recess 7
Since the positioning pins 7a, 7a located at the predetermined positions with respect to b, 7c are fitted into the positioning holes 3a, 3a provided on the printed circuit board 3,
Printed circuit board formed based on the positioning holes 3a, 3a
It will be mounted on the wiring section 3 with high accuracy.

The light emitting element 1 and the light receiving element 2 are
By using the so-called SMD type in which 1a and 2a extend to both sides of the main body part in plan view, the terminals are drawn out from one side of the main body part and the height is higher than in the conventional example using the so-called discrete type. Lowers the overall size of the optical sensor, and the positioning jig 7 is attached to the printed board.
By allowing the terminals 1a and 2a to be seen through the through windows 7d and 7e in a state where the terminals are mounted on the wiring board 3, the wiring portion of the printed circuit board 3 can be easily soldered.

Further, the positioning pins 45a, 45a provided on the light projecting lens 4 and the light receiving lens 5 serve as the positioning holes 3a of the printed circuit board 3 which serve as a reference for the wiring portion on which the light projecting element 1 and the light receiving element 2 are mounted. Since it is directly inserted into 3a, the optical axes of the light projecting lens 4 and the light receiving lens 5 with respect to the light projecting element 1 and the light receiving element 2 can be aligned easily and accurately.

In this embodiment, since the pair of positioning holes 3a, 3a provided on the printed board 3 are both circular, the pair of positioning pins 7 of the positioning jig 7 is formed.
a, 7a and a pair of positioning pins 45a provided on the lens base 45,
If the pitch of 45a varies even a little, it will be difficult to insert it into the pair of positioning holes 3a, 3a, so only one positioning hole 3a is circular and the other positioning hole 3a is shown in Fig. 7 (a). It may be a long hole as shown or a notched hole as shown in FIG.

Further, in this embodiment, the light projecting lens 4 and the light receiving lens 5 are integrally formed by the lens base 45, but they may be separately formed. A pin is provided on each lens, and a positioning hole to be inserted into each pair of positioning pins is provided on the printed circuit board 3.
Need to be installed.

Next, a second embodiment will be described with reference to FIGS. 8 and 9. The members having substantially the same functions as those in the first embodiment are designated by the same reference numerals, and only the differences from the first embodiment will be described.

That is, the light projecting lens 4 and the light receiving lens 5
In the first embodiment, the light passing through is reflected directly to the object, but in this embodiment, the light is reflected to the object through the optical fibers 8 and 9 fixedly supported by the optical fiber supporting member 89.

More specifically, the support member 89 is formed in a flat plate shape, and has a pair of positioning pins 89a, which have the same pitch as the holes that can be fitted into the pair of positioning holes 3a, 3a formed in the printed board 3 at both ends. 89a is erected, and a pair of support holes 89b and 89c are formed on both sides of the center of the light projecting lens 4 and the light receiving lens 5 at the same intervals as the optical fiber.
8, 9 are connected in series with the tip portions fixedly supported in the support holes 89b, 89c.

In addition, the lens base 45 is, in the first embodiment,
A pair of positioning holes 3 provided on the printed circuit board 3 at both ends.
Although a pair of positioning pins 45a, 45a that can be inserted into a, 3a are provided, in the present embodiment, a pair of positioning pins 89a, 89a of the above-mentioned optical fiber supporting member 89 are provided at the same position.
A pair of fitting holes 45b, 45 with the same pitch as the same pin
b is attached.

The support member 89 has positioning pins 89a,
As shown in FIG. 9, 89a is inserted into the insertion holes 45b, 45b and is disposed on the lens base 45, that is, the light projecting lens 4 and the light receiving lens 5, and the optical tube 89a is similar to the first embodiment. The tip end portion is further inserted into the positioning holes 3a and 3a of the printed circuit board 3 while being inserted into the insertion holes 6a and 6a of the printed circuit board 6.

In such an optical sensor, the projection lens 4
Even if the optical fibers 8 and 9 are connected to the light receiving lens 5, the positioning pins 89a and 89a provided on the support member 89 of the optical fiber are the insertion holes 6a and 6a provided on the light projecting lens 4 and the light receiving lens 5, respectively. Since the positioning pins 89a, 89a function as the positioning pins 45a, 45a of the first embodiment by being inserted into the 6a and integrally arranged, the same effect as that of the first embodiment is obtained. Become.

Next, a third embodiment will be described with reference to FIGS. The members having substantially the same functions as those in the first embodiment are designated by the same reference numerals, and only the differences from the first embodiment will be described.

That is, the light projecting element 1 and the light receiving element 2 are
When surface-mounted on the printed circuit board 3, in the first embodiment,
Although the soldering iron is applied to the terminals 1a and 2a viewed through the through-holes 7d and 7e of the positioning jig 7, the wiring is soldered, but in the present embodiment, light is emitted from the through-holes 7d and 7e. It is supposed to be implemented.

Specifically, the printed circuit board 3 includes the light projecting element 1
And the wiring part of the electric signal input / output to / from the light receiving element 2 is formed by applying cream solder.
As shown in, the heat-resistant electronic component 3b other than the light emitting element 1 and the light receiving element 2 is soldered by reflow and mounted on the printed circuit board 3. At this time, the cream solder has hardened.

Then, the positioning jig 7 having stepped portions 7f, 7f at both ends thereof so as not to contact the electronic component 3b is used to position the positioning pins 7a, 7a on the printed circuit board 3 in the same manner as in the first embodiment. When the light emitting element 1 and the light receiving element 2 are inserted into the holes 3a and 3a, only the terminals 1a and 2a are inserted into the through window as shown in FIG.
Looking from 7d and 7e, the main body made of a resin having relatively low heat resistance is positioned on the wiring portion of the printed circuit board 3 in a state of being housed in the recesses 7b and 7c and hidden. Therefore, when light L is emitted from the through windows 7d and 7e of the positioning jig 7, the hardened cream solder is melted and solidified by the heat of the light L, and the terminals 1a and 2a are soldered to the wiring portion. .

In the method of assembling such an optical sensor, as described above, the terminals 1a and 2a seen through the through windows 7d and 7e of the positioning jig 7 are different from the conventional example in which they are mounted by hand soldering. When L is irradiated, the heat melts the solder and connects it to the wiring portion of the printed circuit board 3, so that the light projecting element 1 and the light receiving element 2 can be automatically mounted on the printed circuit board 3.

In each of the first to third embodiments, only one pair of the positioning holes 3a are provided in the printed board 3, but if the mounting area of the printed board 3 is large, three holes are required. More than one may be provided.

[0047]

According to the first aspect of the present invention, the positioning pins provided on the light projecting lens and the light receiving lens serve as a reference for the wiring portion on which the light projecting element and the light receiving element are mounted, and at least a pair of positioning of the printed circuit board is performed. Since it is directly inserted into the hole, the optical axes of the light projecting lens and the light receiving lens can be easily and accurately aligned with the light projecting element and the light receiving element.

According to the second aspect of the present invention, even if the optical fiber is connected to the light projecting lens and the light receiving lens, the positioning pin provided on the supporting member of the optical fiber is provided on the light projecting lens and the light receiving lens. Since the positioning pin is directly inserted into at least one pair of positioning holes provided on the printed circuit board, the same effect as that of claim 1 can be obtained. You can

According to a third aspect of the present invention, the light projecting element and the light receiving element are accommodated in the recess of the positioning jig and positioned, and the positioning pin at a predetermined position with respect to the recess is provided on the printed circuit board. Since it is fitted into at least one pair of positioning holes provided, it can be accurately mounted on the wiring portion of the printed circuit board formed with the positioning holes as a reference.

In addition to the effect of the third aspect, the light emitting element and the light receiving element in the fourth aspect have terminals extending to both sides of the main body portion in plan view, and a wiring portion of the printed circuit board. Using the so-called SMD type, which is surface-mounted on, with the positioning jig mounted on the printed circuit board,
The terminals that are viewed through the through window can be easily soldered to the wiring portion of the printed circuit board. .

In addition to the effect of the invention according to claim 4, in addition to the effect of claim 4, by irradiating the terminal through the through window with light, the solder is melted by the heat and the terminal is printed. Since it is connected to the wiring portion of the board, the light projecting element and the light receiving element can be automatically mounted on the printed board.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention.

FIG. 2 is a front sectional view of the above.

FIG. 3 is an exploded perspective view showing a state in which the above positioning jig is used.

FIG. 4 is a front cross-sectional view showing a state where the above positioning jig is used.

FIG. 5 is a front sectional view of the above positioning jig.

FIG. 6 is a bottom view of the above positioning jig.

FIG. 7 is a plan view showing a modified example of the above printed circuit board.

FIG. 8 is an exploded perspective view showing a second embodiment of the present invention.

FIG. 9 is a front sectional view of the above.

FIG. 10 is an exploded perspective view showing a state in which a positioning jig is used according to the third embodiment of the present invention.

FIG. 11 is a front cross-sectional view showing a state in which the above positioning jig is used.

FIG. 12 is an exploded perspective view showing a conventional example.

[Explanation of symbols]

 1 Light emitting element 1a Terminal 2 Light receiving element 2a Terminal 3 Printed circuit board 3a Positioning hole 4 Light emitting lens 5 Light receiving lens 45a Positioning pin 45b Fitting hole 6 Optical tube 6a Fitting hole 6b Light guiding hole 6c Light guiding hole 7 Positioning jig 7a Positioning pin 7b Recess 7c Recess 7d Through window 7e Through window 8 Optical fiber 9 Optical fiber 89 Support member

Claims (5)

[Claims] 1. A light projecting element which inputs an electric signal and emits light, a light projecting lens which collimates the light emitted from the light projecting element, and a light receiving lens which collects reflected light reflected by an object. Connected to the light receiving element that converts the incident light received from the light receiving lens into an electric signal and outputs it, the optical tube having a pair of light guide holes through which the light passes, and the wiring part of the electric signal to be input and output. A printed circuit board on which the light emitting element and the light receiving element are mounted,
In the optical sensor including, at least a pair of positioning holes are provided in the printed circuit board, and positioning pins fitted into the positioning holes are provided in the light projecting lens and the light receiving lens. Sensor. 2. The positioning pin is provided on a supporting member of an optical fiber, and is also provided on the light projecting lens and the light receiving lens by being fitted into a fitting hole provided therein. The optical sensor according to claim 1. 3. The light, which is input by an electric signal and is emitted from the light projecting element and then becomes parallel by the light projecting lens, is reflected by an object and is then condensed by the light receiving element by the light receiving element to be output as an electric signal. In the method of assembling an optical sensor in which the light emitting element and the light receiving element are mounted on the printed circuit board by connecting to the wiring part of the input / output electric signal, the optical sensor is used to detect the object. The light emitting element and the light receiving element are housed in the concave portion, and the positioning pin at a predetermined position with respect to the concave portion is fitted into at least a pair of positioning holes provided in the printed circuit board, so that the light projecting element and the light receiving element are mounted on the printed circuit board. A method for assembling an optical sensor, characterized in that the optical sensor is mounted on. 4. The positioning jig has a through window through which the terminals of the light projecting element and the light receiving element can be seen, and the terminal is soldered to the wiring portion of the printed circuit board through the through window. A method for assembling the described optical sensor. 5. The method for assembling an optical sensor according to claim 4, wherein the terminal is soldered to the wiring portion of the printed circuit board by irradiating light from the through window.