JPWO2006016504A1 - Optical element for photoelectric sensor and photoelectric sensor using the same - Google Patents

Abstract

An optical element 1 in which a lens body of a coaxial optical system and a mirror for changing a light projecting path are integrated, and the front surface thereof has a convex light receiving surface (11) around a light projecting surface (10). The back surface (12) is formed as a flat surface on which concave portions (13) functioning as prism portions are formed. A collimating lens (15) is integrally provided on the side surface (14) facing the slope of the prism portion (13). A light emitting element (2) is provided at a position facing the collimating lens (15). The light from the light emitting element (2) is collimated by the collimating lens (15) and guided to the inclined surface of the prism part (13), and further totally reflected by this inclined surface to reach the front projection surface (10) for detection. It is guided to the detected object S as a beam. The reflected light from the detected object S received by the light receiving surface (11) is guided toward the back surface (12) while converging inside the optical element (1), and is at a predetermined position behind the back surface (12). Concentrate with. A light receiving element (3) is provided at this condensing position.

Description

  The present invention relates to a reflection type photoelectric sensor that detects the presence or absence of an object, or measures the distance to the object, the size of the object, and the like by receiving reflected light from an object to be detected or a return reflector. In particular, the present invention relates to a photoelectric sensor having a coaxial optical system in which a light projecting path and a light receiving path are set on the same axis.

  FIG. 29 shows a configuration of a typical photoelectric sensor having a coaxial optical system. The photoelectric sensor includes a light projecting unit 205 including a light emitting element 201 and a light projecting lens 202, a light receiving unit 206 including a light receiving element 203 and a light receiving lens 204, and a half mirror 207. The light projecting unit 205 and the light receiving unit 206 are arranged so that their optical axes are orthogonal to each other, and the half mirror 207 is inclined 45 degrees with the reflecting surface facing the light receiving unit 206 at a position where the optical axes intersect. Deployed in state. Light from the light projecting unit 205 is emitted toward the detected object S ahead through the half mirror 207. The reflected light from the detected object S is reflected by the half mirror 207 and guided to the light receiving unit 206.

  In Japanese Patent Publication No. 2004-28598, in addition to the photoelectric sensor having the configuration shown in FIG. 29, the relationship between the light projecting unit and the light receiving unit is reversed, and light from the light projecting unit is transmitted by 90 degrees. A photoelectric sensor having a configuration in which the direction is changed and guided to an object to be detected is described. Further, as an improvement of the configuration of FIG. 29, a photoelectric sensor of a type in which an opening for allowing light from the light projecting unit to pass through is formed at the center of the mirror, or light from the light projecting unit is guided forward. A photoelectric sensor having a configuration in which a light projection guide is provided is described.

  Japanese Published Patent Publication No. 1998,256612 discloses an example in which the light emitting element and the light receiving element are mounted on the same substrate when the light projecting part and the light receiving part are arranged in the same manner as in FIG. ing. In this example, the light receiving element is mounted with its light receiving surface parallel to the substrate surface, while the light emitting element is mounted with its terminals bent 90 degrees so that the light exit surface is orthogonal to the substrate surface. (See FIG. 1 of the same publication).

The numerical aperture of the light receiving lens can be increased by increasing the lens diameter φ and decreasing the focal length f.
On the other hand, in the photoelectric sensor of the type that changes the light receiving path 90 degrees as shown in FIG. 29, in order to efficiently receive the reflected light from the detected object S, the length L that the half mirror 207 occupies on the optical axis. It is desirable to adjust the relationship between the two so that the length corresponds to the diameter of the light receiving lens 204. In such a configuration, if the diameter of the lens 204 is increased in order to increase the amount of received light, the length L must also be increased, so that the depth and thickness of the sensor body also increase. Further, if the length L is reduced in order to reduce the size of the sensor body, the diameter of the lens 204 is reduced. For this reason, it is difficult to simultaneously reduce the size of the sensor body and improve the amount of received light.

  Even in the photoelectric sensor of the type that changes the light projection path side by 90 degrees, even if the focal length of the light receiving lens is shortened for thinning, the sensor body is thinned because the mirror is arranged in front of the light receiving lens. Difficult to do. Further, when the mirror is disposed on the back surface of the light receiving lens, the mirror is disposed in the path condensed by the light receiving lens, so that the amount of light guided to the part other than the light receiving element by the mirror is increased. In addition, in this type of photoelectric sensor, noise due to stray light is generated such that a light projection beam that has not been able to enter the mirror is reflected by the wall or opening of the housing and is incident on the light receiving portion, and the S / N ratio. There is also a problem of lowering.

Further, as described in the second publication, mounting the light emitting element and the light receiving element on the same substrate is also a factor that hinders downsizing of the sensor. This is because an area sufficient to arrange two elements on the substrate must be secured. Moreover, in the configuration of this publication, in order to make the optical axes of the light emitting element and the light receiving element orthogonal to each other, it is necessary to lengthen the connection terminal of one of the elements or to bend and mount it. Will increase.
Further, in the conventional photoelectric sensors, since the lens body and the mirror body are configured as independent parts, there is a problem that the number of assembling steps increases.

  The present invention has been made paying attention to the above-mentioned problems. An optical element in which a lens body and a mirror body are integrated using a resin material is manufactured, and a coaxial optical system is configured using the optical element. Accordingly, the first object is to improve the performance by downsizing the photoelectric sensor and increasing the amount of received light and reducing noise due to stray light.

  A second object of the present invention is to significantly reduce the number of man-hours for assembling a photoelectric sensor and to facilitate manufacture by using the optical element.

A first optical element according to the present invention is a molded body made of a resin material having translucency, and is continuously formed on a light projecting surface for emitting light for detecting an object and outside the light projecting surface. A light receiving surface that forms the front surface of the molded body together with the light projecting surface, a right-angle prism formed as a recess having an opening on the back surface of the molded body, and light incident on the inclined surface of the right-angle prism. A light incident surface. The right-angle prism is formed in a state where the inclined surface faces one side surface of the molded body, and the light incident from the light incident surface is totally reflected by the inclined surface and guided to the light projecting surface. Further, at least one of the light receiving surface and the back surface of the front surface is formed as a lens surface, and the light received by the light receiving surface of the front surface is condensed behind the back surface by the lens surface.
In this specification, the surface of the optical element or photoelectric sensor facing the object to be detected is referred to as “front surface”.

  According to said structure, a coaxial optical system can be comprised by providing a light emitting element in the position which opposes a light-incidence surface, and providing a light receiving element in the position where the light behind a back surface condenses. The light incident surface can be formed on the side surface of the molded body that faces the inclined surface of the right-angle prism, except for the fifth and seventh aspects described later. As will be described later, it is desirable to form the light incident surface as a lens surface. However, the present invention is not limited to this, and if a separate lens is disposed between the light incident surface and the light emitting element, the light incident surface is It may be a flat surface.

  According to the coaxial optical system using the optical element described above, the light from the light emitting element enters the optical element from the light incident surface, is guided to the inclined surface of the right-angle prism, and is then totally reflected by this inclined surface and guided to the light projecting surface. Then, it is emitted forward as a detection beam to the detected object. On the other hand, the reflected light with respect to the detection beam enters the optical element from the light receiving surface on the front surface, travels toward the back surface, passes through the back surface, and enters the light receiving device.

  The front surface of the optical element can be a surface in which a light receiving surface is continuously formed around a light projecting surface. Or it can also be set as the surface of the structure which pinched | interposed the light projection surface by a pair of light-receiving surface like the optical element of the compound eye structure mentioned later. Further, in accordance with the shape of a light projecting / receiving package which will be described later, a surface for sealing and light shielding may be made continuous around the front light receiving surface.

The optical element described above can be considered as an integrated lens body for receiving light and a mirror body for changing the light projection path. Here, the right-angle prism corresponding to the mirror body may have a size corresponding to the width of light incident on the optical element. That is, the thickness of the optical element does not increase even if the mirror for changing the projection path is integrated.
On the other hand, when the aperture of the light receiving lens is increased, the thickness of the optical element is increased, but the distance from the front surface to the condensing point is shortened by increasing the aperture of the light receiving lens. Therefore, even if the lens has a high aperture, the thickness of the optical element does not increase significantly, and the optical element can be thinned.

  In the above optical element, it is desirable to irradiate light having a small variation in angle with respect to the gradient direction of at least the inclined surface of the right-angle prism (preferably light having a constant angle with respect to the gradient direction, that is, collimated light).

  Furthermore, according to the optical element described above, the number of parts constituting the coaxial optical system can be reduced. In addition, since this optical element can be easily manufactured by a method such as injection molding, it is possible to reduce labor and cost required for assembly.

  Further, even when there is light that is incident at an angle that is not guided to the slope of the prism from the side surface including the light incident surface, such as by being reflected from the outside of the optical element, the incident angle is When the angle is larger than the critical angle of total reflection on the back surface, the light is guided to the side surface opposite to the incident side while reflecting the inner surface of the element. Therefore, stray light to the front-side detected object and the back-side light receiving element can be reduced, and noise can be reduced.

As preferred embodiments of the first optical element, seven embodiments are shown below.
First, in the first aspect, the lens surface is formed on one of the light receiving surface and the back surface of the front surface of the molded body, and the other is formed as a flat surface.
When the front light-receiving surface is formed as a lens surface, a part of the light incident on the lens surface (light incident on a portion relatively close to the light projecting surface) is guided in a direction other than the back surface by the lower prism. Therefore, the amount of received light may decrease accordingly. However, even light incident near the outer periphery of the light-receiving surface can be guided to the light-receiving element without escaping to the outside, so that it is possible to cover the loss of the amount of light received by the prism part, and to receive light necessary for object detection. The amount can be secured.

  When the front light-receiving surface is formed as a flat surface and the back surface is formed as a lens surface, light incident near the outer periphery of the light-receiving surface may escape to the outside, but the traveling direction is changed by the right-angle prism. Can reduce the amount of light. With this, the light receiving efficiency can be increased, so that the amount of received light necessary for object detection can be ensured.

  In the second aspect of the optical element, the lens surface is formed on both the front light receiving surface and the back surface of the molded body. According to this configuration, since the two front and rear surfaces of the optical element are lens surfaces, the degree of freedom in designing the lens can be increased and the light condensing performance can be improved.

  In the third preferred aspect of the optical element, the light receiving surface of the front surface is formed as a pair of lens surfaces positioned with the light projecting surface interposed therebetween, and the light received by each lens surface is behind each lens surface. Configured to converge.

The optical element according to the third aspect is an optical element having a compound eye structure in which the light receiving surface is divided into two. When the light receiving surface is formed as a single surface so as to surround the light projecting surface, as described above, a part of the reflected light irradiated to the front surface is guided to the direction other than the back surface by the lower right prism. A loss occurs in the amount of received light. In particular, when the light receiving surface is a lens surface, there is a high possibility that the curvature is set for the entire front surface including the light projecting surface, but if the lens curvature is increased to increase the numerical aperture of the lens, The area affected by the right-angle prism is also increased, and the loss of received light is further increased.
On the other hand, in the optical element having the above-described compound eye structure, the curvature is set for each lens surface for light reception and the light is individually converged, so that it becomes difficult to be affected by the right-angle prism and the loss of light reception is reduced. be able to.

  In the fourth aspect of the optical element, a collimating lens is integrally formed on a side surface of the molded body facing the inclined surface of the right-angle prism, and the light incident surface is formed by a lens surface of the collimating lens.

  According to the above aspect, the light incident on the optical element is immediately converted into collimated light and irradiated as light having an angle of about 45 degrees with respect to the inclined surface of the right-angle prism. Therefore, most of the light incident on the optical element becomes light satisfying the condition of total reflection, and the amount of light guided to the light projecting surface can be increased, so that the intensity of the detection beam can be ensured. Further, it is not necessary to provide a lens between the optical element and the light emitting element, and the number of parts can be reduced.

In the fifth aspect of the optical element, the side surface facing the inclined surface of the right-angle prism and the front light-projecting surface of the molded body are formed as lens surfaces, respectively, and the light incident surface is the side surface facing the inclined surface of the right-angle prism. The lens surface is formed. The light incident surface converts incident light into light having a certain angle with respect to the gradient direction of the inclined surface of the right-angle prism or light converged with respect to the gradient direction. The light projecting surface reflects light guided to the light projecting surface after being totally reflected by the inclined surface of the right-angle prism, or light having a constant width along the width direction of the inclined surface of the right-angle prism or along the width direction. Convert to convergent light.
The light incident surface and the light projecting surface can be formed as a lens surface of a cylindrical lens or a toric lens.

  This aspect is useful when a laser diode is used as the light emitting element and importance is attached to the collimating property of the detection beam. The cross section of the laser light from the laser diode is generally an ellipse with different sizes in two orthogonal directions. However, if this cross section is parallelized with this elliptical cross section, the smaller the diameter, the more depending on the characteristics of the light wave. And collimation is lost.

  When the optical element of the fifth aspect is used, it is necessary to adjust the installation direction of the light emitting element so that the direction in which the divergence of the laser light is large follows the slope of the right prism. When the laser light from the light emitting element adjusted in this way passes through the light incident surface, the light becomes light having a constant width or converges in a direction in which the divergence is large. Further, since the direction in which the divergence is large corresponds to the gradient direction of the inclined surface of the right-angle prism, most of the irradiation light satisfies the condition of total reflection and is guided to the light projecting surface.

  On the other hand, the laser light is emitted in a diverged state in the width direction of the inclined surface of the right-angle prism. Since this diverging state continues after total reflection, the width of the light in this direction gradually increases. However, when passing through the light projection surface, the diverging direction is also converted so as to have a constant width or converge. Therefore, it is possible to emit a detection beam having a substantially circular cross section and a high collimation property or a detection beam having a good light collecting property from the light projecting surface.

  In the sixth aspect of the optical element, a protrusion as a second right-angle prism having a slope parallel to the slope of the right-angle prism is integrally formed on a side surface of the molded body that faces the slope of the right-angle prism. . Further, a collimating lens is integrally formed on the bottom surface of the second right-angle prism (it is considered to be located on the back side in the optical element), and the light incident surface is formed by the lens surface of the collimating lens.

According to the above aspect, when the light emitting element is arranged at a position facing the light incident surface, the light incident from the light emitting element is immediately collimated, and then is formed by the concave portion on the back surface via the second right-angle prism. The light is guided to the first right-angle prism and guided to the light projecting surface. Also in this case, since light having an angle of about 45 degrees with respect to the gradient direction of the slope of the first right-angle prism can be irradiated, most of the irradiation light can be totally reflected and guided to the light projecting surface. .
According to this aspect, since the light incident surface is provided not on the side surface of the optical element but on the back side, the light emitting element can be provided on the back side of the optical element in the same manner as the light receiving element.

Also in the seventh aspect of the optical element, a second right-angle prism similar to the sixth aspect is provided. Further, the bottom surface of the second right-angle prism and the light projection surface of the front surface are each formed as a lens surface, and the light incident surface is formed by a lens surface on the bottom surface side of the second right-angle prism. The light incident surface converts incident light into light having a certain angle with respect to the gradient direction of the slope of the second right-angle prism or light converged with respect to the gradient direction. The light projecting surface reflects light guided to the light projecting surface after being totally reflected by the slope of the first right-angle prism, or light having a constant width along the width direction of the right-angle prism. Convert to light that converges along.
In this embodiment as well, the light incident surface and the light projecting surface can be formed as lens surfaces of a cylindrical lens or a toric lens.

  In the seventh aspect, similarly to the sixth aspect, a light incident surface is formed on the back side of the optical element, and in the same manner as in the fifth aspect, both the light incident surface and the light projecting surface are the lens surfaces. By doing so, the collimating property and light condensing property of the detection beam are improved.

  Next, a second optical element according to the present invention is a molded body made of a resin material having translucency, and is continuous with a light projecting surface for emitting light for detecting an object and the outside of the light projecting surface. The light receiving lens surface that forms the front surface of the molded body together with the light projecting surface, the slit hole that opens on the upper surface or the lower surface side of the molded body, and the slit as a recess having an opening on the upper surface of the molded body A right angle prism formed behind the hole, a light incident surface formed at a position facing one side of the slit hole on the side surface of the molded body, and reflected light from the inclined surface of the right angle prism on the lower surface of the molded body. And a lens surface that protrudes at a passing position. The surface of the slit hole that faces the light incident surface faces a direction in which the light incident from the light incident surface can be totally reflected and guided to the light projecting surface. The right-angle prism is formed such that its inclined surface faces the lower surface of the molded body, and the front light-receiving lens surface converges light received by the surface in the lateral width direction and guides it to the inclined surface of the right-angle prism. The right-angle prism reflects convergent light from the light-receiving lens surface and guides it to the lower lens surface. The lower-surface lens surface transmits reflected light from the inclined surface of the right-angle prism below the lens surface. Collect light.

Even with the optical element having the above configuration, light is projected and received on the front surface, but the received light is condensed below the lower surface of the optical element. That is, light incident from the light incident surface on the side surface is totally reflected by the reflecting surface of the slit hole and guided to the light projecting surface. The light received by the light receiving lens surface is guided to the right-angle prism while converging in the lateral width direction, reflected by the inclined surface, and then passes through the lower lens surface and is condensed below the lens surface.
In addition, since the upper surface and the lower surface of the optical element are for convenience, the received light can be condensed at a position above the optical element if the upper surface is disposed downward in use.

  In the case of the above configuration, the light receiving lens surface needs to have a curvature in the lateral width direction. If the light receiving lens surface is formed in a horizontally long shape using this, the thickness in the vertical direction can be reduced while ensuring the amount of received light. Therefore, it is considered useful when the upper and lower margins of the accommodation space are small.

  The first and second optical elements reflect on the detection beam on the assumption that when the detection beam from the light projecting surface is irradiated onto the object to be detected, the reflected light from the object enters the light receiving surface. It can be used for a photoelectric sensor of a type that outputs an object detection signal when the amount of received light exceeds a predetermined threshold value. It can also be used as a type of photoelectric sensor that is used as a pair with a regressive reflector and outputs an object detection signal when the amount of reflected light with respect to the light from the projection surface falls below a predetermined threshold. it can.

  A photoelectric sensor according to the present invention includes a light projecting / receiving package incorporating the first optical element, a light projecting unit, and a light receiving unit. The light projecting / receiving package is provided with a support portion for supporting the optical element in a state where the light projecting surface and the lens surface are opened forward, and a shielding portion is provided at a rear position of the optical element supported by the support portion. Provided. In addition, an aperture for allowing the light converged by the optical element to pass through is formed in the shielding part, and the light projecting part is disposed on the front side of the shielding part so as to face the light incident surface of the optical element. At the same time, the light receiving unit is arranged on the back side so that the light receiving surface faces the aperture.

The light projecting portion mainly includes a light emitting element such as a laser diode, and can include a support substrate for the light emitting element, a collimating lens, and the like as necessary. The light receiving unit is preferably composed of a photo IC, but is not limited thereto, and may be composed of only a light receiving element such as a photodiode.
In addition, it is desirable to secure a space (including the space by the aperture) according to the focal length of the light receiving system between the optical element and the light receiving unit.

In the case of using the optical element other than the fifth and seventh aspects described above, the light projecting portion is arranged in a state where the light emitting surface is opposed to the light incident surface formed on the side surface of the optical element. The
On the other hand, when the optical elements according to the fifth and seventh aspects are used, the light projecting portion faces the light emitting surface on the front surface side of the shielding portion and the incident surface formed on the back surface side of the optical element. Deployed. In this case, since the light projecting unit is located on the back surface of the optical element in the same manner as the light receiving unit, the light projecting unit is shielded from the space between the optical element and the aperture on the front surface side of the shielding unit. It is desirable to provide a wall for this purpose.

  In the photoelectric sensor according to the present invention, the light emitting / receiving package can be thinned by incorporating the optical element described above. Further, by arranging the light projecting part and the light receiving part in the front and rear sides with the shielding part in between, the width of the package can be reduced, so that the entire sensor can be miniaturized.

  When assembling, for example, the main body of the light emitting / receiving package is arranged with the back side facing the front, the light receiving unit is mounted, then the main body is inverted and the light projecting unit is mounted. An optical element can be attached. As described above, the assembling work is also facilitated, and the production efficiency can be improved.

  In a photoelectric sensor having a preferred configuration, the light emitting / receiving package is housed in a main body case together with a control board. In addition to the drive circuit for the light projecting / receiving unit, the control board can be equipped with a circuit (amplifier circuit, comparator, etc.) for processing the received light amount signal from the light receiving unit.

  In the photoelectric sensor according to a more preferable aspect, the light projecting / receiving package is configured as a three-dimensional injection molded part (MID) in which a circuit for connecting the light projecting unit and the light receiving unit is formed. According to such a configuration, it is possible to easily fix and electrically connect the light projecting unit and the light receiving unit to the shielding unit. In addition, since the package body can be easily manufactured even if the shape is somewhat complicated, it is possible to reduce the labor and time required for manufacturing the sensor and to reduce the cost.

  Furthermore, the light projecting / receiving package is configured as a three-dimensional injection molded part in which a circuit for connecting the light projecting unit and the light receiving unit and a connector unit for connecting to a separate substrate are integrally formed on the surface. Can do. According to such a configuration, the light emitting / receiving package can be easily connected to the substrate by providing the substrate with the connector portion that engages with the connector portion. Also, since the optical element and the light emitting / receiving package are resin molded products, when connecting by soldering, the possibility of deformation or misalignment due to heat must be taken into account. It is not necessary to consider such problems.

  According to the present invention, the coaxial optical system is configured by using an optical element in which a lens body and a mirror body are integrated, so that the photoelectric sensor can be reduced in size, and the amount of received light can be increased and noise caused by stray light can be reduced. The performance can be improved. In addition, the integration of the sensor can reduce the number of assembly steps of the sensor, and the optical element can be easily manufactured by molding using a resin. Therefore, the labor and cost for manufacturing can be greatly reduced. , Mass production can be realized.

It is a perspective view which shows the external appearance of the optical element of the basic composition concerning this invention. It is a front view of the optical element of FIG. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of FIG. It is explanatory drawing which shows the advancing state of the light which injected into the optical element at an angle larger than a critical angle. It is explanatory drawing of the optical element which showed the area which cannot light-receive. It is explanatory drawing which shows the structure of the coaxial optical system by the preferable aspect of the optical element of basic composition. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 1. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 2. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 3. It is a perspective view which shows the external appearance of the optical element of the variation 4. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 4. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 5. It is a perspective view which shows the external appearance of the optical element of the variation 6. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 6. It is explanatory drawing which shows the characteristic of the emitted light of a laser diode. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 7. It is a perspective view which shows the external appearance of the optical element of the variation 8. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 8. It is explanatory drawing which shows the structure of the coaxial optical system using the optical element of the variation 8. It is a disassembled perspective view which shows the structure of a light projection / reception package. It is sectional drawing which shows the structure of a light projection / reception package. It is sectional drawing which shows the other structure of a light projection / reception package. It is sectional drawing which shows the structure of the photoelectric sensor incorporating the light projection / reception package of FIG. It is a perspective view which shows the other example of a connection of a light projection / reception package and a board | substrate. It is a perspective view which shows the other example of a connection of a light projection / reception package and a board | substrate. It is sectional drawing which shows the example which mounts an optical element in a printed circuit board. It is sectional drawing which shows the example which attaches a shielding member to the board | substrate of FIG. It is explanatory drawing which shows a structure when the automatic adjustment function of the light quantity of a laser diode is integrated. It is explanatory drawing which shows the structure of the conventional typical coaxial optical system.

(1) Basic Configuration of Optical Element FIG. 1 shows a configuration example of an optical element for a photoelectric sensor according to the present invention.
The optical element 1 of this embodiment is a molded body made of an optical plastic material such as polymethyl methacrylate (PMMA) or polycarbonate, and an antireflection film is formed on the surface. Note that in FIG. 1 and the following respective drawings (excluding FIGS. 17, 18, 19, and 20) representing the same optical elements, the front surface of the optical element 1 that faces the object to be detected is shown facing upward.

The optical element 1 is used in a reflective photoelectric sensor, and has a front surface in which a convex light receiving surface 11 is continuously formed around a flat circular light projecting surface 10.
The back surface 12 of the optical element 1 is formed as a flat surface, and a recess 13 is formed at the center thereof. The concave portion 13 is a right triangular prism having a rectangular opening, and is adjusted so that the outer contour circumscribes the front projection surface 10 as shown in FIG.

FIG. 3 shows a configuration example of a coaxial optical system using the optical element 1 described above.
In this coaxial optical system, a light emitting element 2 (for example, a laser diode) is disposed at a position facing the slope of the concave portion 13 of the optical element 1, and a light receiving element 3 (for example, a photodiode) is disposed behind the back surface 12. . A collimating lens 25 is disposed between the light emitting element 2 and the optical element 1.

  In the above, after the light from the light emitting element 2 is collimated by the collimating lens 25, the light enters the optical element 1 from the side surface 14 facing the slope of the concave portion 13 of the optical element 1 and reaches the concave portion 13. . In this case, collimated light travels from an optically dense medium (resin) toward a rough medium (air), and the boundary between the two media becomes an inclined surface having an inclination angle of 45 degrees. Collimated light is totally reflected. That is, the concave portion 13 functions as a right-angle prism that guides collimated light to the light projecting surface. Therefore, hereinafter, the concave portion 13 is referred to as a “prism portion 13”.

  The collimated light is totally reflected on the front surface side by the slope of the prism portion 13, passes through the light projecting surface 10, and is applied to the detected object S as a detection beam. If the detected object S is an object having diffuse reflectivity, the reflected light with respect to the irradiation light is irradiated to the front surface of the optical element 1 including the light receiving surface 11. Since the light receiving surface 11 of this embodiment is formed as a convex lens surface, the reflected light that has passed through the light receiving surface 11 is guided to the back surface 12 while converging. In this embodiment, the curvature of the light receiving surface 11 and the refractive index of the optical element are adjusted so that the convergent light is condensed at a predetermined position after passing through the back surface 12. The light receiving element 3 is arranged in accordance with the condensing position of the reflected light.

  In the above embodiment, the light projecting surface 10 is a flat surface, but the present invention is not limited to this. For example, when the detected object S is small, it is desirable to generate a detection beam that converges with the projection surface 10 as a convex surface. Further, when measuring the size (area) of the detection object S, it is desirable to generate a detection beam that diverges with the projection surface 10 as a concave surface.

The optical element 1 can be considered as an integration of a lens body for condensing the reflected light from the detection object S and a mirror body that changes the direction of collimated light from the side by 90 degrees.
In general, when the numerical aperture of the light receiving system is increased, the diameter of the lens can be increased and the focal length can be decreased. In the case of the optical element 1, the numerical aperture can be increased by changing the curvature of the light receiving surface 11, but the thickness of the optical element increases as the curvature increases. On the other hand, the integrated mirror part (prism part 13) that changes the direction of collimated light from the side by 90 degrees only needs to have a size corresponding to the lens diameter of the collimating lens 25. It is not a factor to increase the thickness of 1. Therefore, the thickness of the optical element 1 is increased by increasing the numerical aperture of the light-receiving lens, but the distance from the front surface of the optical element 1 to the condensing point is shortened. Is possible.

Therefore, even if the numerical aperture is increased to increase the amount of received light, the optical element can be reduced in size.
In addition, since the optical element 1 can be integrally formed by injection molding, 2P method, or the like, it is easy to manufacture and the cost can be reduced.

In this embodiment, a shielding member 40 for absorbing light leaking from the lens 25 is provided below the light emitting element 2 and the collimating lens 25. However, there is a possibility that part of the light is reflected by the surface of the shielding member 40 without being absorbed, and the reflected light is incident on the optical element 1 at an angle that is not guided to the slope of the prism portion 13.
However, in the optical element 1 of this embodiment, the light incident at an angle larger than the critical angle of total reflection on the front surface and the back surface is refracted on the inner surface and the side surface opposite to the incident surface as shown in FIG. Proceed to. For this reason, the stray light to the to-be-detected object S side and the light receiving element 3 side can be suppressed, and it becomes possible to reduce noise significantly.

  However, in this optical element 1, since the front light receiving surface 11 is formed as a lens surface, the traveling direction of the reflected light incident on the central portion of the front surface including the light projecting surface 10 is changed by the prism portion 13. There is a problem that the light receiving element 3 is not reached.

FIG. 5 schematically shows a region 100 (hereinafter referred to as “non-light-receiving region 100”) where incidence on the light receiving element is blocked on the front surface of the optical element 1.
In this optical element 1, the curvature of the light receiving surface 11 is set by considering the entire front surface as a lens surface by design. Therefore, when the curvature on the outer peripheral side of the light receiving surface 11 is increased in order to increase the amount of light received, The curvature in the vicinity also increases, and as a result, the non-light-receiving area 100 also increases. Therefore, if the curvature of the light receiving surface 11 is too large, there arises a problem that the light receiving efficiency is deteriorated.

  In the case where the detection of the object S to be detected is hindered by the non-light-receiving area 100 described above, in addition to the light projecting surface 10, the part including the non-light-receiving area 100 is a flat surface and the outer part is a curved surface. You may make it form. Or you may change a design like the variations 1 and 4 etc. which are mentioned later.

FIG. 6 shows a configuration of a coaxial optical system when the optical element 1 is changed to a preferred embodiment.
In the optical element 1 of this embodiment, a collimating lens 15 is integrally provided on the side surface 14 facing the slope of the prism portion 13. The collimating lens 15 replaces the collimating lens 25 of FIG. 3, and the light emitting element 2 is disposed at a position facing the lens surface.

  According to said structure, since the collimating lens 15 is integrated with the optical element 1, the number of parts can further be reduced. Further, it is not necessary to align the lens, and the coaxial optical system can be easily assembled.

(2) Example of optical element design change Hereinafter, the optical element 1 having the configuration shown in FIG. In the following description, the optical elements 1A to 12H are referred to as variations 1, 2,. In any variation, the same or corresponding components as those of the basic optical element 1 are denoted by the same reference numerals in the drawing. Further, description of a configuration that is not different from the basic configuration is omitted or simplified.

<Variation 1>
FIG. 7 shows a configuration of a coaxial optical system including the optical element 1A of variation 1.
In this optical element 1A, the light projecting surface 10 and the light receiving surface 11 are formed as a series of flat surfaces, and the back surface 12 is formed as a convex lens surface. About another structure, it is the same as that of the variation 1 mentioned above.

  According to the above configuration, the reflected light from the object to be detected S is refracted toward the outside by the light receiving surface 11, then travels inside the optical element 1 and reaches the back surface 12. When passing through the back surface 12, the traveling direction of the reflected light is changed to a convergence direction, and as a result, the light is condensed at a predetermined position behind the back surface 12.

  In the optical element 1A, since the light receiving surface 11 is a flat surface, there is a possibility that light incident near the outer periphery of the light receiving surface 11 may escape to the outside. However, the area of the non-light-receiving region 100 described above may be reduced. It is possible to increase the light receiving efficiency.

<Variation 2>
FIG. 8 shows a configuration of a coaxial optical system including the optical element 1B of variation 2.
In this optical element 1B, the front light receiving surface 11 and the back surface 12 are both formed as convex lens surfaces. By providing the lens surfaces having a curvature in this way, the degree of freedom in lens design is improved and the light condensing performance is enhanced. However, if the light receiving surface 11 is curved, the light non-light-receiving area 100 becomes large. Therefore, when the loss of the amount of light received by this area 100 becomes large, it is desirable to make the portion corresponding to the light non-light-receiving area 100 flat. .

<Variation 3>
FIG. 9 shows a configuration of a coaxial optical system including the optical element 1C of variation 3.
In the optical element 1 </ b> C, a right triangular prism-shaped protrusion 16 is integrally provided on a side surface 14 facing the inclined surface of the prism portion 13. The slope of the protrusion 16 is set to be parallel to the slope of the prism portion 13. A collimator lens 15 is integrally provided on the back surface of the protrusion 16. In the optical element 1C, the front light receiving surface 11 is formed as a lens surface and the back surface 12 is formed as a flat surface, as in the basic structure. However, the present invention is not limited to this, and the structures of variations 1 and 2 are adopted. Is also possible.

In the optical element 1 </ b> C, the light emitting element 2 is disposed at a position facing the collimating lens 15, that is, on the back side of the optical element 1. Thereby, the lens surface of the collimating lens 15 functions as an incident surface for incident light for projection, and the protrusion 16 functions as a second prism portion. Therefore, the light from the light emitting element 2 is incident on the lens surface of the collimator lens 14 to be parallel, then totally reflected by the inclined surface of the protrusion 16 and guided to the prism portion 13. Further, the light totally reflected by the prism portion 13 is guided to the detected object S through the light projection surface 10 as in the above-described embodiments. In this manner, the detection beam can be generated by causing total reflection twice in the light incident from the back side.
In this embodiment, since the light emitting element 2 is arranged in the same direction as the light receiving element 3, a shielding part 41 is provided between them.

<Variation 4>
FIG. 10 shows the appearance of the optical element 1D of variation 4, and FIG. 11 shows the configuration of a coaxial optical system including the optical element 1.
In this optical element 1D, the light receiving surface 11 has a compound eye structure in consideration of the problem that the light receiving efficiency is lowered due to the presence of the non-light receiving area 100.

  Specifically, the front surface of the optical element 1 </ b> D has a configuration in which the light receiving surfaces 11 </ b> A and 11 </ b> B are continuously formed on both sides of the band-shaped light projecting surface 10. Each of the light receiving surfaces 11A and 11B is formed as a convex surface having a predetermined curvature, and the direction in which the light receiving surfaces 11A and 11B and the light projecting surface 10 are aligned is parallel to the length direction of the inclined surface of the prism portion 13. I am doing so.

  On the other hand, the back surface 12 is formed as a flat surface as in the basic configuration, and the size and position of the prism portion 13 are adjusted so as to face the light projecting surface 10. In this embodiment, the external collimating lens 25 is used as in the example of FIG. 3, but the collimating lens 15 may be integrated with the side surface 14 as in the example of FIG.

  The light received by each of the light receiving surfaces 11A and 11B converges behind the surfaces and is condensed at different positions. Behind the back surface 12, light receiving elements 3A and 3B are provided for the light condensing positions of the regions 11A and 11B, respectively.

  According to the optical element 1D having the above configuration, the curvatures of the light receiving surfaces 11A and 11B are individually set. Therefore, even if the curvature near the light projecting surface 10 is increased, the curvature of the prism portion 13 is not affected. Reflected light can be guided to the back side, and the light receiving efficiency can be increased. Further, when setting the same numerical aperture as that of the optical element 1 having a configuration in which the light receiving surface 11 is not divided (monocular configuration), by setting the curvature for each of the light receiving surfaces 11A and 11B, the light receiving surfaces 11A and 11B Since the total area can be made smaller than the area of the light receiving surface 11 having a monocular structure, the optical element 1 can be made smaller.

<Variation 5>
FIG. 12 shows a configuration of a coaxial optical system including the optical element 1E of variation 5.
The concave portion 13 of the optical element 1E has a shape in which a triangular prism is connected to the tip of a quadrangular prism whose cross section is much smaller than that of the concave portion 13 of the previous embodiments, and the triangular prism 13a at the tip functions as a prism portion. A condensing lens 17 is integrally provided on the side surface 14 facing the slope of the prism portion 13a. Further, a collimating lens 18 is integrally provided at the center of the front surface, and the lens surface is set as the light projecting surface 10. The light receiving surface 11 is a lens surface similar to the basic configuration, and the back surface 12 is also formed as a flat surface similar to the basic configuration.

  The lens surface of the condenser lens 17 on the side surface 14 functions as a light incident surface that receives light from the light emitting element 2. The formation position of the prism portion 13 a is adjusted so that the prism portion 13 a is located at a height facing the upper portion of the condenser lens 17. Further, the optical axis of the light emitting element 2 is set lower than the optical axis on the condenser lens 17 side so that the refraction direction of the light incident on the upper part of the condenser lens 17 from the light emitting element 2 becomes substantially horizontal. By such adjustment, most of the light incident on the condenser lens 17 from the light emitting element 2 satisfies the condition of total reflection with respect to the inclined surface of the prism portion 13a. This makes it possible to guide the same amount of light to the light projecting surface 10.

The light that has reached the light projecting surface 10 is converted into collimated light when passing, and is irradiated on the detected object S as a detection beam. The optical path followed by the reflected light from the detected object S is the same as the basic configuration.
According to the optical element 1E configured as described above, since the prism portion 13a is minimized, the area of the non-light-receiving region 100 can be extremely reduced. Therefore, the light receiving efficiency can be increased.

<Variation 6>
FIG. 13 shows the appearance of the optical element 1F of variation 6, and FIG. 14 shows the configuration of the coaxial optical system including this optical element 1F.
In this optical element 1 </ b> F, cylindrical lenses 101 and 102 are integrally provided on portions corresponding to the side surface 14 facing the slope of the prism portion 13 and the front projection surface 10, respectively. Since the light emitting element 2 is disposed opposite to the cylindrical lens 101 on the side surface, the lens surface functions as a light incident surface.

  In this variation 6, a laser diode 21 having the characteristics shown in FIG. In this laser diode 21, laser light emitted from the front light emitting layer 21a becomes light having different degrees of divergence in two orthogonal directions (x direction and y direction), that is, light spreading in an elliptical shape. When such light passes through the collimating lens, the cross-section of the light after being collimated also becomes elliptical, but due to the nature of the light wave, it gradually spreads in the small diameter direction (x direction). Collimation is lost.

The optical element 1F of the variation 6 corrects the cross section of the laser beam into a circular shape, and uses the corrected laser beam as a projection beam.
In FIG. 14, the laser diode 21 is arranged with the y direction aligned with the vertical direction on the paper surface and the x direction aligned with the direction perpendicular to the paper surface. The cylindrical lens 101 on the side surface 14 converts the light emitted from the laser diode 21 into light whose divergent state in the y direction is corrected, that is, light that travels along the horizontal direction. This light spreads with respect to the width direction of the slope of the prism portion 13, but the light is irradiated at an angle of about 45 degrees with respect to the slope direction of the slope, so that most of the light is totally reflected. The condition is satisfied and guided to the light projecting surface 10. Even after the light is reflected, the diverging state in the direction corresponding to the x direction continues, so the width of the light in this direction gradually increases. However, when the light passes through the cylindrical lens 102 on the front surface, Is converted into collimated light that is maintained. Accordingly, it is possible to emit a detection beam having a nearly circular cross section from the light projecting surface 10 and having a high collimating property.

  A toric lens may be provided in place of the cylindrical lens 102. Since the cross section of the laser light immediately before being emitted from the light projecting surface 10 is close to a circle, by providing a toric lens on the light projecting surface 10, the laser light close to the circular shape is converged with a good light collecting property. Can be converted to light. In addition, the cylindrical lenses 101 and 102 are both changed to toric lenses, and the cross-section of the laser beam immediately before being emitted from the light projecting surface 10 is controlled to be closer to a circle, so that the collimation property and light condensing property of the detection beam are increased. You may make it raise.

  For the optical element 1C of the variation 3 shown in FIG. 9, the collimating lens 15 is changed to a cylindrical lens or a toric lens for the same purpose as the variation 6, and the light projecting surface 10 is also a cylindrical lens or a toric lens. It can be formed as a lens surface.

<Variation 7>
FIG. 16 shows a configuration of a coaxial optical system including the optical element 1G of variation 7.
The configuration of the optical element 1G is almost the same as the basic configuration, but a large number of minute recesses 111 are formed on the light receiving surface 11. These micro concave portions 111 allow the optical element 1 to function as a diffractive lens. Therefore, the curvature of the light receiving surface 11 can be reduced, and the non-light receiving area 100 can be reduced. Moreover, since the light condensing power can be increased by the individual minute recesses 111, the thickness of the optical element 1 can be reduced.

In addition, according to the optical element 1G, the degree of freedom in design can be improved, for example, the positions of the prism portion 13 and the light projecting surface 10 can be easily changed.
In order to efficiently guide light from the prism portion 13 upward, it may be better to dispose the prism portion 13 and the light projecting surface 10 away from the center. All of the optical elements of the embodiments presented so far are made by molding, but it is difficult to manufacture the mold unless it is a surface of the axis, so the position of the front projection surface is biased. There is a problem that such an optical element cannot be easily manufactured.

  On the other hand, in the variation 7, after forming the main body of the optical element 1G, the minute concave portion 111 can be formed on the front surface by using a photolithography technique. It can be easily changed. Therefore, the positions of the prism portion 13 and the light projecting surface 10 can be easily changed according to the circumstances of the design, the degree of freedom in design can be improved, and the function of the optical element 1 can be enhanced.

<Variation 8>
FIG. 17 shows the configuration of the optical element 1H of variation 8. Further, FIG. 18 shows a configuration of the coaxial optical system including the optical element 1H viewed from above, and FIG. 19 shows a configuration of the same coaxial optical system viewed from the lateral direction.
In this optical element 1H, laterally long light receiving surfaces 112 and 113 are continuously formed on both sides of the band-shaped light projecting surface 10, respectively. The light receiving surfaces 112 and 113 constitute a cylindrical lens together with a portion behind the light receiving surfaces 112 and 113.

  Further, the optical element 1H is provided with a slit hole 131 having a predetermined thickness and a triangular prism-shaped concave portion 132 that functions as a prism portion. All of these open at the upper surface 121 of the optical element 1H. A collimating lens 15 similar to the basic configuration is provided on the side surface 14 that receives light from the light emitting element 2. The slit hole 131 is in a state where the width direction thereof is inclined by about 45 degrees with respect to the main axis L of the optical element 1H, and the rear end side is close to the side surface 14.

  On the other hand, the concave portion 132 is formed so that the inclined surface faces the slit hole 131 and the lower surface 122 of the optical element 1H. Further, a cylindrical lens 103 for condensing light is integrally provided at a position facing the inclined surface of the concave portion 132 of the lower surface 122.

  The light emitting element 2 is provided at a position facing the collimating lens 15 on the side surface 14, and the light receiving element 3 is provided at a position facing the cylindrical lens 103 on the lower surface 122. Light from the light emitting element 2 is collimated by the collimating lens 15 and reaches the slit hole 131. The facing surface 133 of the slit hole 131 to the collimating lens 15 functions as a reflecting surface that totally reflects light from the collimating lens 15, similarly to the slope of the prism portion 13 having the basic configuration. Therefore, the collimated light is totally reflected by the surface 133 of the slit hole 131 and guided to the light projecting surface 10 and is emitted as a detection beam.

  On the other hand, the light received by each of the light receiving surfaces 112 and 113 travels toward the back surface 12 while converging in the lateral width direction of the optical element 1, and is irradiated onto the inclined surface of the prism portion 132 in the middle of the path. Each of the light receiving surfaces 112 and 113 is set so that the vertical direction (up and down direction of the optical element 1H) is a flat surface or its curvature is small. Small and light from a direction close to the horizontal direction can be irradiated. Therefore, most of the light applied to the slope of the prism portion 132 is totally reflected and guided to the cylindrical lens 103 below, and the light condensed by the lens 103 enters the light receiving element 3.

  In the optical element 1H configured as described above, since the slit hole 131 and the prism portion 132 must be disposed, the depth becomes slightly longer. However, since it is necessary to converge the received light in the lateral width direction, the thickness in the vertical direction can be suppressed while securing the amount of received light by making the front surface a horizontally long shape. Therefore, it can be said that the optical element 1 of the variation 8 is a configuration suitable for installation in a space where there is no allowance in the vertical direction.

In the above configuration example, the opening of the slit hole 131 is set to the upper surface 121, but the present invention is not limited to this, and the opening may be made on the lower surface 122. Or you may comprise as a through-hole which opened both the upper surface 121 and the lower surface 122. FIG.
Further, the upper surface 121 and the lower surface 122 of the optical element 1H are for convenience, and may be reversed upside down according to the convenience of use.

  Moreover, the variation of an optical element is not limited to eight types mentioned above, You may combine the structure concerning these variations suitably. For example, for an optical element having a compound eye structure such as variation 4, the front light-receiving surfaces 11A and 11B may be formed as flat surfaces and the back surface 12 as a lens surface. Further, variations 4 and 6 may be combined, and the light incident surface and the light projecting surface of an optical element having a compound eye structure may be configured as a lens surface of a cylindrical lens or a toric lens.

(3) Configuration Example of Light Emitting / Receiving Package The optical elements 1 and 1A to 1H of the basic configuration and variations 1 to 8 described above are incorporated into a resin package together with the light emitting element 2 and the light receiving element 3. Hereinafter, a package in which these elements are integrated is referred to as a “light emitting / receiving package”.

20 and 21 show specific examples of the light projecting / receiving package.
The light emitting / receiving package 5 has a main body 4 that is a three-dimensional injection-molded part (MID) made of a high heat-resistant liquid crystal polymer or the like, and is integrally formed with a shielding part 43 having an aperture 45 therein. is there. An accommodation space 46 for the optical element 1 and the light projecting unit 20 is formed in front of the shielding unit 43. A step portion 42 for supporting the optical element 1 is formed at the front end portion of the inner peripheral surface of the main body portion 4. An accommodation space 47 for the light receiving unit 30 is formed between the back surface of the shielding unit 43 and the rear end edge of the main body unit 4. Furthermore, a circuit pattern 48 for connecting to the control board 6 to be described later is formed on the outer peripheral surface of the frame portion 3 and the mounting positions of the light projecting portion 20 and the light receiving portion 30.

  In this embodiment, the optical element 1 having the basic configuration shown in FIG. 6 is used. However, the optical element 1 of this embodiment is slightly modified in accordance with the shape of the main body 4. Specifically, the light receiving surface 11 is formed in a circular shape, and a plate-like body 105 is continuously formed around the light receiving surface 11. The outer shape and size of the plate-like body 105 correspond to the stepped portion 42 of the main body portion 4. Further, the light receiving surface 11 and the light projecting surface 10 are on one side of the plate-like body 105 (on the left side in the illustrated example) so that the collimating lens 15 and the light projecting portion 20 facing the collimating lens 15 are hidden by the plate surface of the plate-like body 105. It is deployed with bias.

The light receiving unit 30 is a photo IC in which a photodiode 31 and a signal processing circuit (not shown) are integrated. The photo IC 30 is flip-chip mounted on a circuit pattern 48 formed on the back side of the shielding portion 43 via an underfill material (not shown). On the other hand, the light projecting unit 20 has a configuration in which the laser diode 21 is mounted on the silicon intermediate substrate 22, and is wire-bonded and die-bonded to the circuit pattern 48 formed on the front surface of the shielding unit 43. The optical element 1 is disposed in the front space 46 of the shielding part 43 so that the lower surface of the plate-like body 16 is supported on the step part 42 after the light projecting part 20 is mounted. The optical element 1 is fixed in the main body 4 by adhering a joint portion between the plate-like body 16 and the frame portion 4 with a photocurable resin 49 or the like.
For the purpose of automatically adjusting the light quantity of the laser diode 21, a photodiode for detecting the light quantity of the laser diode 21 may be provided on the intermediate substrate 22.

  The aperture 45 of the shielding portion 43 communicates the front and rear spaces 46 and 47 and is formed at a position corresponding to a light passing region that converges from the optical element 1. Further, the arrangement position of the photodiode 31 of the photo IC 30 is also adjusted so as to correspond to the outlet of the aperture 45.

  The laser diode 21 of the light projecting unit 20 of this embodiment is of a side emission type. The light emitted from the laser diode 21 enters the collimating lens 15 of the optical element 1 and is collimated, then totally reflected by the inclined surface of the prism portion 13, and further, the object to be detected via the light projecting surface 10. To S. Reflected light from the object to be detected S passes through the optical element 1 through the light receiving surface 11, and then is guided from the back surface 12 to the photodiode 31 through the aperture 45.

  The optical element 1 having a lens-shaped light incident surface (shown in FIGS. 1 and 3) and the optical elements 1A, 1B, 1E, 1F, and 1G of variations 1, 2, 5, 6, and 7 are used. Also in the case of using, the main body 4 having the same configuration as in FIG. 20 can be used. Further, when the variation 4 optical element 1D is used, the configuration is the same as that of FIG. 20 except that two apertures are formed in the shielding portion 43 and two photodiodes 31 are incorporated in the photo IC 30. Can do. On the other hand, when the optical element 1H of the variation 8 is used, a main body having a shape corresponding to the optical element 1H is created, and the aperture 45 and the photo IC 30 are positioned on the lower surface side of the optical element 1H. Need to be changed.

  FIG. 22 shows a configuration of the light projecting / receiving package 5 when the configuration of the optical element 1C of the variation 3 is applied. The main body portion 4 of this embodiment is basically of a construction in which a shielding portion 43 is formed inside, as in the embodiment of FIGS. It is formed behind the embodiment of FIG. In this embodiment, since the light projecting unit 20 is disposed on the back side of the optical element 1, the thickness of the shielding unit 43 is reduced, and the light from the light projecting unit 20 is formed on the front side of the shielding unit 43. A wall 41a is formed to project the light. The tip of the wall 41a is aligned with the step 42.

  A support portion 106 having a width and thickness suitable for the step portion 42 is integrally provided on the outer periphery of the optical element 1 of this embodiment. Since the support portion 106 is formed so as to surround the second prism portion 16 on the side, a triangular prism-shaped recess 107 is also formed on the front side.

  The light receiving unit 30 is configured by a photo IC similar to the embodiment of FIG. 21 and is mounted on the back side of the shielding unit 43. On the other hand, the light projecting unit 20 of this embodiment is composed of only the laser diode 21 and is mounted in a region surrounded by the shielding unit 43 and the wall 41a. The laser diode 21 of this embodiment is of the type having a light emitting surface on a surface parallel to the mounting surface (upper surface in the drawing).

  In the light emitting / receiving package 5 shown in FIGS. 21 and 22, the optical element 1 can be made thin. Furthermore, since the light projecting unit 20 and the light receiving unit 30 can be arranged forward and backward by utilizing the fact that the main body unit 4 is configured by three-dimensional injection molding, the width direction of the main body unit 4 can also be reduced. Thus, the light emitting / receiving package 5 can be reduced in size. Further, as described above, the light receiving efficiency can be increased by increasing the numerical aperture of the optical element 1 and the noise due to stray light can be reduced. Therefore, the detection accuracy of the detected object can be greatly increased.

  In any example, after mounting the photo IC 30 with the back side of the main body 4 facing the front, the main body 4 is inverted and the light projecting unit 20 is mounted, and finally the optical elements 1 and 1C are attached. Thus, the light emitting / receiving package 5 can be completed. Therefore, the assembly work is extremely easy. In addition, since the optical elements 1 and 1C and the main body 4 can be easily manufactured by integral molding, the manufacturing efficiency can be improved, the cost can be reduced, and mass production can be realized. it can.

(4) Configuration Example of Photoelectric Sensor FIG. 23 shows a configuration of a photoelectric sensor in which the light projecting / receiving package 5 according to the embodiment of FIGS. Although the photoelectric sensor to which the embodiment of FIG. 21 is applied is not shown, it can be configured in substantially the same manner as this embodiment.

  The photoelectric sensor of this embodiment is constructed by incorporating the light emitting / receiving package 5 and the control board 6 in a case body 7 having a front opening. The light emitting / receiving package 5 is supported with the front surface of the optical element 1 facing the opening of the case body 7, and a control board 6 is provided behind it. The control board 6 is mounted with a drive circuit for the laser diode 21, a circuit for secondary processing of the output from the signal processing circuit of the photo IC 30, and a circuit for relaying the output to the outside. The circuit pattern 48 of the light emitting / receiving package 5 is soldered to a terminal (not shown) on the control board 6. In the figure, 61 and 62 are components on the control board 6, and 71 is a cable including a power supply line and a signal line.

  However, since the optical sensor 1 and the main body 4 of the light projecting / receiving package 5 are formed of resin, the photoelectric sensor having the above configuration can be deformed by heat during processing when soldered to the substrate 6 as described above. There is sex. Further, the resin 49 that bonds the optical element 1 and the main body 4 may melt, and the optical element 1 may be displaced.

24 and 25 show a configuration example for solving the above problem. In these embodiments, the components 61 and 62 on the substrate 6 are not shown.
In the embodiment of FIG. 24, a male connector 50 is integrally formed at the lower end edge of the main body 4, and a female connector 60 corresponding to the connector 50 is also provided on the substrate 6. On the surface of the connector 50, terminals 48a of the circuit pattern 48 are formed. Since the main body 4 of the light emitting / receiving package 5 is an MID, the connector 50 can be easily formed.

  In the embodiment of FIG. 25, a male connector 51 is formed to protrude from the side surface of the main body 4. On the other hand, the substrate 6 is narrow and slightly thick, and a female connector (not shown) is provided on one side thereof.

24 and 25, it is possible to connect the light emitting / receiving package 5 and the substrate 6 very easily. Moreover, there is no possibility that the main body 4 and the optical element 1 are affected by heat, and the performance of the photoelectric sensor can be improved.
Further, in the embodiment of FIG. 25, since the substrate 6 is attached to the side surface of the light emitting / receiving package 5, the photoelectric sensor can be made thinner than the embodiment of FIG. 24 in which the light emitting / receiving package 5 is stacked on the substrate 6. it can.

FIG. 26 shows another example of a photoelectric sensor using the optical element 1.
The photoelectric sensor of this embodiment does not use the light emitting / receiving package 5 described above, but is a type in which the optical element 1 is mounted on a printed circuit board 64. The optical element 1 is the same as the basic structure described above, but extension portions 108 and 109 each having a predetermined width are continuously formed on both sides. Further, the optical element 1 is supported horizontally between a pair of support walls 114 and 115 that can stand vertically. These support walls 114 and 115 are also formed integrally with the main body of the optical element 1.

Three through holes 65, 66 and 67 are formed in the substrate 64. Among them, the left and right through holes 65 and 66 are for inserting the support walls 114 and 115, and the central through hole 67 functions as an aperture through which the light received by the optical element 1 passes.
Further, a light projecting unit 20 is provided on the front side of the substrate 64, and a light receiving unit (photo IC) 30 is provided on the back side. The light projecting unit 20 and the photo IC 30 are both the same as those in the example of FIGS. 21 and 22, but a spacer member 23 is provided between the light projecting unit 20 and the substrate 6. In addition, an underfill material 33 is injected into the gap between the photo IC 30 and the substrate 6 for buffering.

  In order to assemble the photoelectric sensor having the above configuration, first, the photo IC 30 is mounted on the back surface side of the substrate 64 in a state where the photodiode 31 is aligned with the through hole 67. Next, the light projecting unit 20 is mounted at a predetermined position on the front surface. Thereafter, the support walls 108 and 109 are inserted into the through holes 65 and 66, and the position of the optical element 1 is adjusted while confirming the collimating property of the detection beam and the amount of light received by the photo IC 30. When this adjustment is completed, the photocurable resin 49 is injected into the gap between the through holes 65 and 66 to fix the optical element 1. Finally, the polarizing filter 8 is attached to the support walls 108 and 109 so as to block the front of the optical element 1.

  The substrate 64 on which the optical element 1 is mounted is accommodated in a case body (not shown) constituting the main body of the photoelectric sensor. Since the optical element 1 can be made thin, the case body can also be made thin, and the downsizing of the photoelectric sensor can be realized.

  In the configuration example of FIG. 26, light from the light projecting unit 20 may enter the photodiode 31 through the through hole 67. Therefore, as shown in FIG. 27, it is desirable to shield the space between the light projecting unit 20 and the through hole 67 by inserting a shielding member 74 into the through hole 67.

(5) Light quantity control of photoelectric sensor The photoelectric sensor according to the present invention can be added with a function (APC control) for automatically adjusting the light quantity of the laser diode using the characteristics of the optical element 1.
FIG. 28 shows the configuration of the photoelectric sensor when this APC control is added. In the optical element 1 of this embodiment, a second prism portion 19 is added to the basic configuration. The second prism portion 19 is formed so as to protrude from the side surface facing the collimating lens 15 with the prism portion 13 interposed therebetween. Further, the photo IC 30 includes a photodiode 32 for receiving the total reflected light from the second prism portion 19 in addition to the photodiode 31 for receiving the reflected light collected by the optical element 1. Is deployed. The photo IC 30 is also provided with a signal processing circuit (not shown) for the second photodiode 32.

  The light that has passed through the collimating lens 15 on the side surface 14 is guided to the light projecting surface 10 by the central prism portion 13 and is totally reflected. However, the slope of the prism portion 13 is completely reflected on the slope of the prism portion 13 due to errors during molding processing. Therefore, some light that goes straight through the space constituting the prism portion 13 is generated. In this embodiment, light that has traveled straight without being reflected by the central prism portion 13 is received by the second prism portion 19 and guided to the second photodiode 32 of the photo IC 30. Then, in the signal processing circuit of the photo IC 30, the amount of light received by the second photodiode 32 is measured, and the measured value is fed back to the drive circuit of the laser diode 21, thereby adjusting the light quantity of the laser diode 21.

  The photoelectric sensor using the optical element having each configuration described above receives the reflected light from the object to be detected with respect to the detection beam from the light projecting surface, thereby detecting the object, the distance to the object, and the size of the object. It can be configured to measure the thickness. Further, by using it as a pair with the regressive reflecting plate, it is also possible to configure so that an object is detected when the reflected light with respect to the light from the light projecting surface falls below a predetermined threshold value.

Claims (12)

A molded body made of a resin material having translucency,
A light projecting surface for emitting light for detecting an object, a light receiving surface formed continuously outside the light projecting surface and forming the front surface of the molded body together with the light projected surface, and an opening in the back surface of the molded body A right angle prism formed as a recess having a light incident surface for allowing light guided to the inclined surface of the right angle prism to be incident,
The right angle prism is formed in a state in which the inclined surface faces one side surface of the molded body, and the light incident from the light incident surface is totally reflected by the inclined surface and led to the light projecting surface,
At least one of the light receiving surface on the front surface and the back surface is formed as a lens surface, and this lens surface is an optical element for a photoelectric sensor that collects light received by the light receiving surface on the front surface behind the back surface.   The optical element for a photoelectric sensor according to claim 1, wherein the lens surface is formed on one of a light receiving surface and a back surface on the front surface of the molded body, and the other is formed as a flat surface.   The optical element for a photoelectric sensor according to claim 1, wherein the lens surface is formed on both a light receiving surface and a back surface of the front surface of the molded body.   2. The photoelectric sensor according to claim 1, wherein the light receiving surface of the front surface is formed as a pair of lens surfaces positioned with a light projecting surface interposed therebetween, and light received by each lens surface is converged behind each lens surface. Optical element for sensors.   2. The optical sensor for a photoelectric sensor according to claim 1, wherein a collimator lens is integrally formed on a side surface of the molded body facing the inclined surface of the right-angle prism, and the light incident surface is formed by a lens surface of the collimator lens. element. The side surface facing the inclined surface of the right-angle prism of the molded body and the light projecting surface of the front surface are each formed as a lens surface, and the light incident surface is formed by the lens surface of the side surface facing the inclined surface of the right-angle prism,
The light incident surface converts incident light into light having a certain angle with respect to the gradient direction of the inclined surface of the right-angle prism or light converged with respect to the gradient direction, and the light projection surface is the right-angle prism. 2. The light guided to the light projecting surface after being totally reflected by the inclined surface of the right angle prism is converted into light having a constant width along the width direction of the inclined surface of the right-angle prism or light converged along the width direction. An optical element for the described photoelectric sensor. A protrusion as a second right-angle prism having a slope parallel to the slope of the right-angle prism is integrally formed on a side surface of the molded body facing the slope of the right-angle prism.
The optical element for a photoelectric sensor according to claim 1, wherein a collimating lens is integrally formed on a bottom surface of the second right-angle prism, and the light incident surface is formed by a lens surface of the collimating lens. A protrusion as a second right-angle prism having a slope parallel to the slope of the right-angle prism is integrally formed on a side surface of the molded body facing the slope of the right-angle prism.
The bottom surface of the second right-angle prism and the light projection surface of the front surface are each formed as a lens surface, and the light incident surface is formed by a lens surface on the bottom surface side of the second right-angle prism,
The light incident surface converts incident light into light having a certain angle with respect to the gradient direction of the slope of the second right-angle prism or light converged with respect to the gradient direction, The light totally reflected by the slope of the first right-angle prism and guided to the projection surface is converted into light having a constant width along the width direction of the right-angle prism or light converged along this width direction. An optical element for a photoelectric sensor according to claim 1. A molded body made of a resin material having translucency,
A light-projecting surface for emitting object detection light; a light-receiving lens surface that is continuously formed on the outside of the light-projecting surface and forms the front surface of the molded body together with the light-projected surface; and an upper surface of the molded body or A slit hole that opens on the lower surface side, a right-angle prism formed behind the slit hole as a recess having an opening on the upper surface of the molded body, and a position that faces the slit hole on one side of the molded body A light incident surface, and a lens surface formed to project at a position where reflected light from the inclined surface of the right-angle prism on the lower surface of the molded body passes,
The surface of the slit hole on the side facing the light incident surface faces a direction in which the light incident from the light incident surface can be totally reflected and guided to the light projecting surface,
The right-angle prism is formed in a state where the inclined surface faces the lower surface of the molded body, and the front light-receiving lens surface converges light received by the surface in the lateral width direction and guides it to the inclined surface of the right-angle prism. The right-angle prism reflects convergent light from the light-receiving lens surface and guides it to the lower lens surface, and the lower-surface lens surface transmits reflected light from the inclined surface of the right-angle prism below the lens surface. Optical element for photoelectric sensor to condense. A photoelectric sensor comprising an optical element made of a molded body made of a resin material having translucency, and a light projecting / receiving package incorporating a light projecting part and a light receiving part,
The optical element includes a light projecting surface for emitting light for detecting an object to the outside, a light receiving surface that is continuously formed outside the light projecting surface, and forms a front surface of the molded body together with the light projecting surface; A right-angle prism formed as a recess having an opening on the back surface of the molded body, and a light incident surface for allowing light guided to the inclined surface of the right-angle prism,
The right angle prism is formed in a state in which the inclined surface faces one side surface of the molded body, and the light incident from the light incident surface is totally reflected by the inclined surface and led to the light projecting surface,
At least one of the light receiving surface and the back surface of the front surface is formed as a lens surface, and by this lens surface, the light received by the light receiving surface of the front surface is condensed behind the back surface,
The light emitting / receiving package is provided with a support portion that supports the optical element in a state where the light projecting surface and the light receiving surface are opened forward, and a shielding portion is provided at a rear position of the optical element supported by the support portion. Provided,
An aperture for allowing the light converged by the optical element to pass through is formed in the shielding part, and the light projecting part is arranged on the front side of the shielding part so as to face the light incident surface of the optical element. In addition, the photoelectric sensor is arranged on the back side so that the light receiving unit is disposed so that the light receiving surface faces the aperture.   The photoelectric sensor according to claim 10, wherein the light projecting / receiving package is a three-dimensional injection-molded part in which a circuit for connecting the light projecting unit and the light receiving unit is integrally formed on a surface.   11. The three-dimensional injection-molded part in which the light projecting / receiving package is formed integrally on the surface with a circuit for connecting the light projecting unit and the light receiving unit and a connector unit for connecting to a separate substrate. The photoelectric sensor described in 1.

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