JP2000277796A - Photosensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensor with which the light projected form a light emitting element is not reflected fully on the surface of resin, even if the object is at a very close position. SOLUTION: This photosensor 1 has a light emitting element 4 and a light receiving element 5 in a pair and a screen wall 6 made outside it and is provided with an opening which serves as a light path. In this case, the light emitting element 4 and the light receiving element 5 are coated with transmissive resin, and the interior of the screen wall 6 is made hollow, and this hollow is filled with air. Many pieces of photosensors 1 are formed integrally on an assembling board, and then they are diced and manufactured into individual photosensors 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensor and a method of manufacturing the same, and more particularly, to a photosensor having a pair of light emitting elements and light receiving elements provided side by side, and emitting light from the light emitting elements. The present invention relates to a photo sensor that projects light onto a measurement object, receives light reflected by the measurement object with a light receiving element, and detects the presence or absence of the measurement object based on the amount of light, and particularly, the photo sensor is very close to the photo sensor. The present invention relates to a photosensor suitable for detecting a measurement target existing at a position and a method for manufacturing the same.

[0002]

2. Description of the Related Art A photosensor according to the present invention detects the presence or absence of an object to be measured in a non-contact manner. In practice, the photosensor simply detects the presence or absence of reflected light caused by the presence or absence of the object to be measured. Not only does it detect presence,
A portion having a different reflectance is provided on the measurement object to change the amount of the reflected light, and the change in the amount of the reflected light detects the presence or absence of a portion having a high reflectance (or a portion having a low reflectance). It is used for detecting the number of revolutions of a rotating body such as a motor, detecting the end of paper or film, or a marked position. Further, it may be used for detecting an analog light amount change due to a change in the distance or angle to the reflection unit.

FIG. 5 shows the basic structure of a photosensor according to the present invention. Photo sensor 50 shown in FIG.
Is a light emitting element 52 (for example, an infrared ray LE) on an insulating substrate 51.
D) and the light receiving element 53 (for example, a phototransistor) is 1
They are juxtaposed as a pair, and have a structure in which the periphery is shielded by a shielding wall 54 made of a light-shielding resin. The shielding wall 54 constitutes an entire casing and includes an outer wall (external shielding wall) 54a for shielding the light-emitting element 52 and the light-receiving element 53 (particularly, the light-emitting element 52) from external light, and the light-emitting element 52 and the light-receiving element 53. And an intermediate wall (intermediate shielding wall) 54b that shields the light emitting elements 5 from each other.
The opening 54c on the second side and the opening 54d on the light receiving element 53 side
Is formed as an optical path of light projected from the light emitting element 52, reflected by the measurement object 55, and received by the light receiving element 53. A light-transmitting protective resin 56 capable of transmitting light is molded inside the shielding wall 54, and the light-emitting element 5 is formed.
2 and the light receiving element 53 are sealed and protected.

In this photosensor 50, light emitted from a light emitting element 52 is projected from an opening 54 c on the light emitting element 52 side as shown by an arrow and reflected by a measurement object 55, and the reflected light is reflected by a light receiving element 53. Light receiving element 5 through the opening 54d on the side
3 and the light amount is detected by the light receiving element 53. In this case, the amount of light detected by the light receiving element 53 increases or decreases depending on the presence or absence of the measurement object 55 (the presence or absence of a portion where the reflectance of the measurement object 55 changes), thereby increasing or decreasing the output from the light receiving element 53. The presence or absence of the measurement object 55 (the presence or absence of a portion where the reflectance of the measurement object 55 changes) is detected by the increase or decrease of the output of the light receiving element 53.

FIG. 6 shows such a photosensor.
As shown in the example, heretofore, it was individually manufactured one by one. That is, the photo sensor 60 shown in FIG.
The light emitting element 6 is connected to the lead terminals 62 and 63 disposed on
4 and the light-receiving element 65, respectively, and a light-transmitting resin 66 such as an epoxy resin is molded on the light-receiving element 65 to seal and protect the light-emitting element 64 and the light-receiving element 65. The package 67 is formed by molding a package 67 made of a light-shielding resin such as a resin or a polyphenylene sulfide resin (hereinafter, referred to as a PPS resin). The translucent resin 66 here is
It means a resin that transmits the light projected from the light emitting element 64, not a so-called transparent resin. For example, when the light emitting element 64 is an infrared LED, an opaque visible light blocking epoxy resin that transmits infrared light and blocks visible light is often used.

However, in such a method of manufacturing a photosensor, since the photosensors are individually manufactured one by one, the manufacturing cost has to be extremely high. For this reason, a manufacturing method of a multi-cavity photosensor using a collective substrate in which a large number of photosensors are formed on a collective substrate formed of a large-sized insulating substrate and then diced and divided into individual photosensors has been developed. An example of a method for manufacturing this multi-cavity photosensor is shown in FIG. 4 which is an embodiment of the present invention.

In this method of manufacturing a multi-cavity photosensor, as shown in FIG. 4, a large number of light emitting elements 4 and light receiving elements 5 are arranged and bonded on a collective substrate 11 composed of a large insulating substrate. Conductive patterns 3a and 3b are provided in parallel, and through holes 12a and 12b connected to the conductive patterns 3a and 3b are connected to connection terminals (not shown) provided on the lower surface side of the collective substrate 11. Then, the light emitting element 4 and the light receiving element 5 are juxtaposed and bonded at predetermined positions on the collective substrate 11.

The light emitting element 4 and the light receiving element 5 are arranged side by side, and a collective substrate 11 made of a large-sized insulating substrate bonded is molded with a light transmitting resin (epoxy resin or the like). The light receiving element 5 is sealed and protected. As shown in FIG. 7, which is a diagram of a photosensor divided and individually divided, a resin block 74a for sealing the light emitting element 72 and a resin block 74b for sealing the light receiving element 73 In addition, the resin blocks 74a and 76b have a package (shielding wall) made of a light-shielding resin (epoxy resin containing black pigment, PPS resin, or the like) on the entire outside except for the opening on the upper surface. Molded at 75, a large number of photosensors are integrally formed on the collective substrate 11.

By dicing the plurality of photosensors into individual photosensors 70, as shown in FIG. 7, a pair of light emitting elements 72 and light receiving elements 73 are provided.
A light shielding element (package 75) that shields the light from each other and also shields external light, and obtains a photosensor 70 in which light projected from an opening thereof is reflected by a measurement object 76 and received by a light receiving element 73. be able to.

Alternatively, a resin block 74a for sealing the light emitting element 72 and a resin block 74 for sealing the light receiving element 73
By coating a light-shielding film 77 on the outer periphery except for the opening on the upper surface with the light-receiving element b, as shown in FIG. A photosensor 70 having a wall (a light-shielding film 77), in which light projected from an opening thereof is reflected by the measurement object 76 and received by the light-receiving element 73, can be obtained. Here, FIG. 8A shows an example in which the insides of the side surfaces of the resin blocks 74a and 74b made of a translucent resin are formed perpendicular to the insulating substrate 71, and FIG. The inside of the side surfaces of 74a and 74b is formed on an inclined surface having a small diameter on the opening side, and the light reflected on the inside of these side surfaces is also projected on the measurement object 76, so that the light receiving element 7
3 is an example in which the light amount of the light received at 3 is to be increased.

[0011]

In each of these photosensors 70, the light-emitting element 72 and the light-receiving element 73 are molded with a translucent resin 74 such as an epoxy resin. As described above, when the light projected from the light emitting element is refracted when projected from the sealing resin 80 to the outside air layer, and when this angle θ exceeds the critical angle
As shown in (b), the light is totally reflected and no light is projected to the outside.

When the measuring object 76 is in a very close position, as is clear from FIGS. 7 and 8,
Since the angle of light projected from the light emitting element 72 and reflected by the measurement object 76 and received by the light receiving element 73 increases,
The light may be totally reflected within the resin 74 beyond the critical angle θc and may not be projected to the outside. In particular, as shown in FIG. 8B, a light-shielding film 77 is coated with an inclined outer wall surface of a translucent resin 74, and the light reflected on the inner surface of the outer wall surface is also projected on the measurement object 76. In the case where the light amount is to be increased by this, when the measurement object 78 is approached, the light is totally reflected immediately and cannot contribute to the increase in the light amount. When the angle θ of the light approaches the critical angle θc, the transmitted light becomes polarized and the transmittance of the light decreases, and the light is reflected by the measurement object 76, even if the light does not reach total reflection. The light amount of the light received by the light receiving element 73 is also greatly reduced.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pair of light emitting element and light receiving element juxtaposed on an insulating substrate, and the pair of light emitting element and light receiving element are mutually connected. Shielding and shielding from external light, and a shielding wall having an opening on the light emitting element side and the light receiving element side forming an optical path for receiving light projected from the light emitting element with the light receiving element, The light emitted from the light emitting element is projected from the opening on the light emitting element side, and the reflected light reflected by the object to be measured is received by the light receiving element through the opening on the light receiving element side, and the light amount is used as the light quantity. In a photosensor for detecting the presence or absence of an object to be measured, the shielding wall surrounds both the pair of the light emitting element and the light receiving element, and an external shielding wall formed as a whole as a hollow, the light emitting element and the light receiving element In between The light-emitting element and the light-receiving element are coated with a translucent resin, and the inside of the external shield wall is formed as a hollow part, and the hollow part is filled with air. The present invention provides a photosensor characterized in that:

Here, it is preferable that the inside of the external shielding wall is formed as an inclined surface having a small diameter on the opening side. Further, it is preferable that a light reflecting film is formed on an inclined surface having a small diameter at least on the opening side inside the external shielding wall.

According to another aspect of the present invention, there is provided a light emitting element and a light receiving element provided side by side, and a pair of the light emitting element and the light receiving element are shielded from each other and external light is provided. And a shielding wall having an opening that forms an optical path for receiving light emitted from the light emitting element with the light receiving element, through the opening provided in the shielding wall, and The light receiving element receives the reflected light emitted from the light emitting element and reflected by the object to be measured, and includes a photosensor for detecting the presence or absence of the object to be measured based on the amount of light. After arranging and forming a large number of photosensors on a collective substrate, a method for manufacturing a multi-cavity photosensor using a collective substrate that is diced and divided into individual photosensors, the light emitting element on the collective substrate and A resin coating step of coating the outer periphery of the light receiving element with a translucent protective resin; an outer shielding wall formed in a hollow surrounding the light emitting element and the light receiving element in pairs; Said shielding wall consisting of an intermediate shielding wall arranged in the middle of the element,
A shielding wall forming step of forming as an aggregate of a large number of shielding walls corresponding to the arrangement of the pair of light emitting elements and the light receiving elements on the aggregate substrate; And a shielding wall joining step in which the light emitting element and the light receiving element are joined at predetermined positions in which a pair of the light emitting elements and the light receiving elements are respectively accommodated.

Here, it is preferable that a reflecting film forming step of forming a light reflecting film on the inner surface of the shielding wall formed in the shielding wall forming step is provided as a step before the shielding wall bonding step.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the photosensor of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a partially cutaway perspective view. As shown in the figure, in the photosensor 1 of the present invention, a light emitting element 4 such as an LED and a light receiving element 5 such as a phototransistor are arranged side by side on conductive patterns 3a and 3b provided on an insulating substrate 2. And the surrounding area is covered by a shielding wall 6 so as to shield external light. The shielding wall 6 includes an external shielding wall 6a for shielding external light, and a plate-shaped intermediate shielding wall 6b for mutually shielding between the light emitting element 4 and the light receiving element 5. An opening 6c on the light emitting element 4 side and an opening 6d on the light receiving element 5 side, which are optical paths of the light to be received and the light received by the light receiving element 5, are provided. This shielding wall 6
Is made of a light-shielding resin such as an epoxy resin or a PPS resin containing a black pigment, as described above, or a light reflection film is formed on the inner surface to prevent light from transmitting therethrough. The transmission of light other than 6d is blocked.

The outer circumferences of the light emitting element 4 and the light receiving element 5 are coated in a thin film with translucent resins 7 and 8, such as epoxy resin, to protect the light emitting element 4 and the light receiving element 5. Here, as described above, the term “translucent resin” means a resin that transmits light projected from the light emitting element 4 and is not limited to a so-called transparent resin.
For example, when the light emitting element 4 is an LED that projects visible light, a so-called transparent resin is used.
Is an infrared LED, an apparently black and opaque visible light blocking epoxy resin that transmits infrared light and blocks visible light can be used.

The shielding wall 6 in the embodiment of the present invention is shown in FIG.
As shown in FIG. 8B, the inside of the side surface is formed on an inclined surface where the opening has a small diameter, and as described in the description of FIG.
The light reflected by the inclined surface inside the side surface is also projected on the measurement object 9 to increase the amount of light received by the light receiving element 4. The inner surface of the side surface of the shielding wall 6 can increase the amount of light reflected on the inner surface of the shielding wall 6 by making the inner surface a smooth glossy surface. Further, by depositing or plating metal as a thin film on the inner surface of the shielding wall 6, a metal thin film is coated on the surface to form a reflective film 10, and light reflected on the inner surface of the side surface of the shielding wall 6 is formed. Can be further increased. The inside of the shielding wall 6 surrounded by the outer shielding wall 6a and the intermediate shielding wall 6b is a hollow portion,
This hollow portion is filled with an air space.

The photosensor 1 of the present invention is manufactured by the following steps. That is, as shown in FIG.
Conductive patterns 3a and 3b for arranging and bonding a large number of light emitting elements 4 and light receiving elements 5 on a collective substrate 11 composed of a large-sized insulating substrate are provided in parallel by a collective substrate manufacturing process similar to the prior art. Conductive patterns 3a, 3
b and connection terminals (not shown) provided on the lower surface side of the collective substrate 11 by through holes 12a and 12b, and then, by a bonding process, a predetermined portion of the collective substrate 11 manufactured in the previous collective substrate manufacturing process. The light emitting element 4 and the light receiving element 5 are arranged side by side at a position and are bonded.

The outer periphery of the light emitting element 4 and the light receiving element 5 bonded side by side on the collective substrate 11 in this bonding step are coated with light-transmitting protective resins 7 and 8 such as epoxy resin in a thin film form, respectively. A resin coating process is performed. The light-transmitting protective resins 7 and 8 coated in this resin coating step are
It is intended to prevent the light-receiving element 5 from being deteriorated by exposing the light-receiving element 5 to the air, and as described above, is a resin that transmits light projected from the light-emitting element (not a transparent resin). For example, in the case of visible light, a transparent epoxy resin or the like is used. In the case where the light emitting element 4 is an infrared LED, an opaque visible light blocking epoxy resin or the like that transmits infrared light and blocks visible light is used. used.

In this resin coating step, a monomer of a light-transmitting protective resin such as a transparent epoxy resin or an opaque visible light-blocking epoxy resin is diluted with a solution, and the diluted solution is luminescent by spin coating or brushing. It is applied to the periphery of the element 4 and the light receiving element 5, dried, and coated to a thickness of several μm to several tens μm.

On the other hand, in the shielding wall forming step, the pair of the light emitting element 4 and the light receiving element 5 are shielded from each other, the external light is shielded, and the light projected from the light emitting element 4 passes through a predetermined optical path. A shielding wall assembly (not shown) in which a large number of shielding walls 6 having openings 6c and 6d for receiving the reflected light by the light receiving element 5 via a predetermined optical path and reflected by the measurement object 9 are arranged in a matrix. To manufacture. This shielding wall assembly has a plate-shaped intermediate portion in which a hollow portion formed by an external shielding wall 6a surrounding a pair of the light emitting element 4 and the light receiving element 5 is disposed between the light emitting element 4 and the light receiving element 5. Two hollow portions are separated by the shielding wall 6b, and these hollow portions have shapes continuous with the openings 6c and 6d, respectively, and the outer shielding walls 6a are arranged in a matrix in a continuous manner with each other. Therefore, a large number of hollow portions arranged two by two are arranged in a matrix at the same pitch as the light emitting element 4 and the light receiving element 5. Then, this shielding wall assembly is molded by a single resin molding process.

As described above, the shielding wall 6 is made of a light-shielding resin such as an epoxy resin or a PPS resin containing a black pigment, or a light reflection film is formed on the inner surface thereof so as not to transmit light. I do. The reflection film forming step of forming the light reflection film is performed by depositing or plating a metal as a thin film on the inner surface of the shielding wall 6, and coating the surface with the metal thin film to form the reflection film 10.

The shield wall assembly manufactured in this manner is joined to a predetermined position on the collective substrate 11 by a shield wall joining step. It goes without saying that this joining position is joined to a predetermined position where the pair of light emitting element 4 and light receiving element 5 are shielded and housed. In this bonding step, any bonding method such as bonding with an adhesive or a double-sided tape or ultrasonic bonding can be adopted.

In the photosensor assembly thus joined, the inside of the shielding wall 6 has a hollow portion, and it is clear that the hollow portion has an air layer filled with air. . Finally, the photosensor assembly process is completed by dicing the photosensor assembly into individual photosensors 1. The dicing method is well known and will not be described in detail here.

[0027]

According to the photosensor of the present invention, the light-transmitting resin for sealing and protecting the light-emitting element and the light-receiving element is coated only in a thin film, and is molded with the light-transmitting resin. Since it has not been done, as shown in FIG.
Since the light emitted from the light emitting element is projected and reflected by the measurement target as shown by the light path indicated by the arrow, the light emitted from the light emitting element is projected from the sealing resin to an external air layer. In this case, the light is not refracted when the light is transmitted, and it never happens that the light is totally reflected beyond the critical angle and the light is not projected to the outside. Further, the transmitted light is polarized as the light angle approaches the critical angle, and the light transmittance does not decrease.

For this purpose, a light-emitting element and a light-receiving element are provided side by side, and the light emitted from the light-emitting element is projected onto the object to be measured, and the light reflected by the object is received. In a photosensor that receives light by an element and detects the presence or absence of a measurement target based on the amount of light, it is possible to reliably detect a measurement target even at a very close position. In addition, the inside of the side surface of the light-transmitting resin is inclined to have a smooth surface, or a reflective film is coated. However, the reflected light that is not totally reflected beyond the critical angle and reflected inside the side surface can be used effectively.

Further, according to the photosensor manufacturing method of the present invention, it is possible to easily manufacture the photosensor of the present invention, which can detect an object to be measured in a very close position. In addition, a step of sealing with a light-transmitting resin is not required, and a mold for sealing the light-transmitting resin is not required, so that the device can be manufactured at lower cost as compared with the related art.

Further, in the photosensor of the present invention, since the protective resin such as epoxy resin for protecting the light emitting element and the light receiving element is only coated in a thin film shape, the resin stress due to cooling during molding or a change in temperature is reduced. Does not occur, and it is also possible to prevent current-carrying deterioration particularly likely to occur in infrared LEDs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a photosensor of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially cutaway perspective view of the embodiment of FIG. 1;

FIG. 4 is a perspective view of a collective substrate showing a multi-cavity manufacturing method.

FIG. 5 is a schematic diagram showing a basic configuration of a photosensor according to the present invention.

FIG. 6 is a cross-sectional view showing an example of a conventional photosensor.

FIG. 7 is a cross-sectional view showing an example of a conventional photosensor manufactured by a multi-cavity manufacturing method.

8A and 8B are cross-sectional views illustrating another example of a conventional photosensor manufactured by a multi-cavity manufacturing method, wherein FIG.
Is an example in which the shielding wall is vertical, and (B) is an example in which the shielding wall is inclined.

FIG. 9 is an explanatory view showing refraction of light on the surface of a translucent resin, where (a) shows an example in which light is refracted and projected;
(B) is an example of total reflection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensor 1 2 Insulating substrate 3a, 3b Conductive pattern 4 Light emitting element 5 Light receiving element 6 Shielding wall 6a External shielding wall 6b Intermediate shielding wall 6c Opening 7,8 Translucent resin 9 Object to be measured 10 Reflective film 11 Assembly substrate 12a, 12b Through hole

Claims (5)

[Claims] 1. A pair of light-emitting and light-receiving elements juxtaposed on an insulating substrate, mutually shielding the pair of light-emitting and light-receiving elements from external light, and projecting light from the light-emitting element. And a shielding wall having an opening on the light emitting element side and an opening on the light receiving element side for forming an optical path for receiving the light to be received by the light receiving element, and an opening on the light emitting element side for emitting light emitted from the light emitting element. A photosensor that receives light reflected by the measurement object through the opening on the light receiving element side and receives the light reflected by the measurement object, and detects the presence or absence of the measurement object based on the amount of light. An outer shielding wall surrounding the pair of the light emitting element and the light receiving element and formed as a whole as a whole, and an intermediate shielding wall disposed between the light emitting element and the light receiving element. Element and said Photosensor, characterized in that coated by translucent resin on the outer periphery of the optical element, the inside of the outer shield wall and a hollow portion, the air is filled in the hollow portion. 2. The photosensor according to claim 1, wherein the inside of said external shielding wall is formed on an inclined surface having a small diameter on the opening side. 3. The photosensor according to claim 1, wherein a light reflection film is formed on an inclined surface having a small diameter at least on the opening side inside the external shielding wall. 4. A pair of light emitting element and light receiving element provided side by side, and shielding the pair of light emitting element and light receiving element from each other and from outside light, and projecting light from the light emitting element. And a shielding wall having an opening for forming an optical path for receiving the light with the light receiving element, through the opening provided in the shielding wall, and projecting light from the light emitting element, depending on an object to be measured. The reflected light is received by the light receiving element,
It consists of a photo sensor that detects the presence or absence of the object to be measured by the amount of light, and after forming and arranging a large number of the photo sensors on a collective substrate made of a large insulating substrate, the collective substrate is divided into individual photo sensors. In the method for manufacturing a multi-cavity photosensor, a resin coating step of coating the outer periphery of the light emitting element and the light receiving element on the collective substrate with a transparent protective resin; The above-mentioned shielding wall consisting of an external shielding wall formed in a hollow surrounding each pair and an intermediate shielding wall disposed between the above-mentioned pair of light-emitting elements and the light-receiving element is provided by the above-mentioned pair of light-emitting elements on the collective substrate. A shaping wall forming step of shaping the shading as an aggregate of a large number of shielding walls corresponding to the arrangement of the light receiving elements; A multi-piece photo-printing method using a collective substrate, comprising: a shielding wall joining step in which a pair of chips are respectively housed in predetermined positions in which a pair is accommodated; and a dicing step in which dicing is performed and divided into individual photo sensors. Manufacturing method of sensor. 5. A shielding film forming step of forming a light reflecting film on an inner surface of the shielding wall formed in the shielding wall forming step, as a pre-process of the shielding wall joining step. A manufacturing method of the photosensor described in the above.