JP7118466B2 - light sensor - Google Patents

Description

The present invention relates to an optical sensor comprising a light-emitting element and a light-receiving element.

As the above optical sensor, there has been proposed an optical sensor comprising a package in which a light-emitting element and a light-receiving element are arranged on a substrate with a predetermined gap therebetween and integrated by resin molding. This optical sensor is a reflective sensor that detects an object by receiving light reflected by a light-receiving element when light emitted from a light-emitting element strikes an object. This reflective sensor is provided with means for preventing light emitted laterally from the light-emitting element from entering the light-receiving element and lowering the detection sensitivity of the light-receiving element. The means for this is a means for performing a light shielding process by evaporating a metal thin film on the side surface of the light receiving element (see, for example, Patent Document 1).

Japanese Patent Publication No. 4-33395

In the optical sensor disclosed in Patent Document 1, the light-emitting element and the light-receiving element are arranged on the substrate with a predetermined gap therebetween. In addition, there is also the inconvenience that the light-shielding process by evaporating a metal thin film is a laborious task.

SUMMARY OF THE INVENTION In view of the above situation, the present invention aims to provide an optical sensor that can reduce the size of the package in the horizontal direction and that does not require light shielding.

In order to solve the above problems, the optical sensor of the present invention is configured in an integrated package by mounting a light emitting element that emits light in a direction away from the light receiving element on the light receiving surface of the light receiving element that receives light. The light-receiving element is set to a wavelength range in which the light emitted by the light-emitting element cannot be received, and the light-emitting element is turned on or off when the light-receiving element receives the incident light. Alternatively, it is characterized in that it is configured to change the lighting state.

According to the above configuration, since the light emitting element that emits light to the side opposite to the light receiving surface is mounted on the light receiving surface of the light receiving element that receives light and is integrated, the light receiving element and the light emitting element are mounted on the substrate. The size in the horizontal direction can be reduced compared to the case where the are arranged at predetermined intervals in the horizontal direction. Moreover, since the light-receiving element is set to a wavelength range in which the light emitted by the light-emitting element cannot be received, it is not necessary to vapor-deposit a metal thin film for light-shielding treatment, and the The output of the light receiving element can be greatly reduced with respect to the irradiated light. Further, when the light receiving element receives the incident light, the light emitting element in the off state lights up, the light emitting element in the on state goes off, or the lighting state changes (the color changes or changes from the lighting state to the blinking state). or change from a blinking state to a lit state), it is possible to confirm that light is incident on the light receiving element simply by looking at the light emitting state of the light emitting element.

In the optical sensor of the present invention, the light-receiving surface of the light-receiving element receives light in a wavelength range different from the wavelength range of the light emitted by the light-emitting element. An optical filter that cuts light in a specific wavelength range may be provided.

As described above, by cutting light in a specific wavelength range in order to receive light in a wavelength range different from the wavelength range of light emitted by the light emitting element with the optical filter, the light incident on the light receiving surface is cut. Light incident on the light-receiving surface of the light-receiving element can be reliably received. Moreover, when an optical filter is provided, the wavelength range can be easily changed by simply replacing it with various optical filters having different characteristics including transmittance and polarization direction.

In the optical sensor of the present invention, a sealing resin for sealing the light receiving element converts light emitted from the light emitting element into light of a wavelength having a low light receiving sensitivity, and It may also contain one or more color phosphors to tone the color of the light emitted from it.

As described above, since the encapsulating resin contains phosphors of one color or multiple colors, the light emitted from the light-emitting element can be converted into light of a wavelength with low light-receiving sensitivity, and light is emitted. The color of the light emitted from the device can be toned.

Further, the optical sensor of the present invention may be configured to operate as a reflection sensor in which light emitted from the light emitting element and reflected by a reflecting object is received by the light receiving element.

According to the present invention, by mounting the light-emitting element on the light-receiving surface of the light-receiving element and providing the light-receiving element for receiving light in a wavelength range different from the wavelength range of the light emitted by the light-emitting element, It is possible to provide an optical sensor that can reduce the size of and does not require a light shielding treatment.

BRIEF DESCRIPTION OF THE DRAWINGS The first embodiment of the optical sensor of the present invention is shown, (a) is a plan view, (b) is a front view, and (c) is a front view in which a reflector is arranged above. 2nd Embodiment of the optical sensor of this invention is shown, (a) is a top view, (b) is a front view, (c) is a front view which has arrange|positioned the reflector above. 2 is a graph showing the intensity of light with respect to the wavelength range of a light-emitting element and a light-receiving element, where (a) shows a case where a light-receiving element with extremely low light-receiving sensitivity to the emission wavelength is used, and (b) shows a predetermined wavelength range. A case of using a cut light-receiving element is shown. FIG. 10 is a front view of an optical sensor in which a wavelength-converting phosphor is mixed in resin, showing a third embodiment of the optical sensor of the present invention. FIG. 12 is a front view showing a fourth embodiment of the optical sensor of the present invention, showing a configuration in which two sensors are arranged to face each other and two-way optical communication is performed.

<First embodiment>
1(a), (b), and (c) show an optical sensor 1. FIG. This optical sensor 1 includes a substrate 2 and a light receiving element 3 mounted on the upper surface 2A of the substrate 2, a light emitting element 4 mounted on the light receiving surface 3A which is the upper surface of the light receiving element 3, and the light emitting element 4 and the light receiving element 3 sealed. A single package is provided with a sealing resin (for example, silicone resin or epoxy resin) 5 made of a translucent material for sealing. Further, two bonding wires 6 and 7 connecting the light emitting element 4 and the substrate 2 and one bonding wire 8 connecting the light receiving element 3 and the substrate 2 are provided.

The substrate 2 is rectangular in plan view (square, circular, or polygonal) and is made of glass epoxy resin or a lead frame structure.

The light-emitting element 4 is arranged at the center of the light-receiving surface 3A of the light-receiving element 3 so that the light from the light-emitting surface 4A is emitted to the side away from the light-receiving element 3 (specifically, as shown in FIGS. 1B and 1C). As shown, the light emitting surface 4A is arranged facing upward in the same manner as the light receiving surface 3A of the light receiving element 3) and is smaller than the light receiving element 3 in a rectangular shape (square, circular, polygonal, etc.). ). Although the light emitting element 4 is arranged in the center of the light receiving surface 3A of the light receiving element 3 here, the light emitting element 4 may be arranged in a position other than the center of the light receiving surface 3A. Further, for example, FIG. 3A shows a wavelength range (sensitivity wavelength range) 9 of the light receiving element 3 indicated by a dotted line in which the light receiving sensitivity to the emission wavelength indicated by a solid line is extremely small. Specifically, the wavelength range of the light emitting element 4 is 380 nm to 440 nm, and the light emitting element 4 emits light with a peak wavelength of 400 nm. FIG. 3(b) also shows the wavelength range 11 of the light receiving element 3 indicated by the dotted line, in which the light receiving sensitivity to the emission wavelength indicated by the solid line is extremely low. The wavelength range 12 of the light emitting element 4 is 400 nm to 500 nm, and the light emitting element 4 may be configured to emit light with a peak wavelength of 450 nm. The wavelength range of the light emitting element 4 of the present invention can be freely changed.

The light-receiving element 3 is formed in a rectangular shape (which may be square, circular, polygonal, or the like) larger than the light-emitting element 4 so that the light-receiving surface 3A is exposed. Moreover, the light receiving element 3 has a wavelength range in which the light receiving sensitivity with respect to the emission wavelength is extremely low, as shown in FIG. 3(a), for example. Specifically, the wavelength range is 400 nm to 1100 nm, and the peak wavelength is 1000 nm. FIG. 3(b) also shows the wavelength range of the light receiving element 3 in which the predetermined wavelength range from 300 nm to 600 nm is cut and the light receiving sensitivity with respect to the emission wavelength is extremely small. Specifically, the light receiving element 3 may have a wavelength range of 600 nm to 1100 nm and a peak wavelength of 780 nm. The wavelength range of the light receiving element 3 of the present invention can be freely changed. In short, the light receiving element 3 is set to have a wavelength range (sensitivity wavelength range) in which the light emitted by the light emitting element 4 cannot be received. In the graphs of FIGS. 3A and 3B, the vertical axis represents relative intensity (sensitivity) and the horizontal axis represents wavelength (nm).

FIG. 1(b) shows a case where the optical sensor 1 constructed as described above is used as an optical sensor with an indicator. The optical sensor 1 includes a control unit (not shown) for causing the light emitting element 4 to emit light based on the received light signal when the light receiving element 3 receives the incident light 13 . Therefore, when the light-receiving element 3 receives the incident light 13, the light-emitting element 4 in the off state emits light (visible light) 14 to operate as an indicator lamp that lights up. At this time, the wavelength range of light received by the light receiving element 3 and the wavelength range of light emitted by the light emitting element 4 are different ranges as described above. Since the light-emitting element 4 is configured to operate as an indicator lamp in this manner, the light is received simply by looking at the light-emitting state of the light-emitting element 4 (in this case, the light (visible light) 14 of the light-emitting element 4 that is lit). It can be confirmed that the light 13 has entered the element 3 . Further, when the light receiving element 3 receives the incident light, the light emitting element 4 in the lighting state is extinguished or the lighting state is changed (the color changes, or the lighting state changes from the lighting state to the blinking state, or from the blinking state to the lighting state). ) configuration.

Further, FIG. 1(c) shows a case where the optical sensor 1 is used as a reflection sensor. That is, the light 17 (light converted into a wavelength range different from the wavelength range of the light 15 emitted from the light emitting element 4) reflected by the reflecting object (object) 16 from the light 14 emitted from the light emitting element 4 is converted into By receiving light with the light receiving element 3, it functions as a reflection sensor capable of detecting the reflecting object 16. FIG.

As described above, since the light-emitting element 4 is mounted on the light-receiving surface 3A of the light-receiving element 3 and integrated, the light-receiving element and the light-emitting element are arranged on the substrate with a predetermined interval in the horizontal direction. Therefore, the horizontal size can be reduced. Moreover, since the light-receiving element 3 is configured to receive light in a wavelength range different from the wavelength range of the light emitted by the light-emitting element 4, it is not necessary to vapor-deposit a metal thin film for light-shielding treatment. , the output of the light receiving element 3 can be greatly reduced with respect to the light emitted from the light emitting element 4 . Further, as shown in FIG. 1(c), when the optical sensor 1 is used as a reflection sensor, the light 15 emitted from the light emitting element 4 hits a reflecting object (object) 16, and the reflected light 17 is converted into light. The light can be efficiently received by the light receiving element 3 arranged at a position as close as possible to the optical axis 4L of the element 4. FIG.

<Second embodiment>
In the first embodiment, the light 13 directly incident on the light receiving element 3 shown in FIG. 1B and the light 15 emitted from the light emitting element 4 shown in FIG. Although the light 17 emitted from the light emitting element 4 has a wavelength range different from that of the light 15 emitted from the light emitting element 4, in FIGS. 2, an optical filter 18 is provided for cutting light in a specific wavelength range in order to receive light in a wavelength range different from the wavelength range of light emitted by the light emitting element 4 from the light incident on the light receiving surface 3A. . FIG. 3(b) shows the wavelength range of the light-receiving element 3 in which the wavelength range of 300 nm to 600 nm is cut by the optical filter 18. As shown in FIG. Moreover, when an optical filter is provided, the wavelength range can be easily changed by simply replacing it with various optical filters having different characteristics including transmittance and polarization direction.

2A, 2B, and 2C, the configurations other than the configuration in which the optical filter 18 is provided on the light receiving surface 3A of the light receiving element 3 are the same as those in FIGS. 1A, 1B, and 1C. Since they are the same, they are denoted by the same reference numerals and their description is omitted. 2(b) shows a case where the optical sensor 1 is used as an optical sensor with an indicator, as in FIG. 1(b), and FIG. It shows the case where the sensor 1 is used as a reflection sensor.

<Third Embodiment>
In the second embodiment, an optical filter 18 is provided on the light-receiving surface 3A of the light-receiving element 3 to convert light incident on the light-receiving surface 3A into light in a wavelength range different from the wavelength range of the light emitted by the light-emitting element 4. Although the case is shown, as shown in FIG. 4, the sealing resin 5 may contain the phosphor 19 of one color or plural colors. The phosphor 19 can convert the light 14 emitted from the light-emitting element 4 into light having a wavelength with low light-receiving sensitivity, and can adjust the color of the light emitted from the light-emitting element 4. . For example, when a blue light-emitting element is used, red and green phosphors or yellow and red phosphors are used so that the light emitted from the sealing resin 5 to the outside of the chip can emit white light. . In FIG. 4, the light 14 emitted from the light emitting element 4 hits the phosphor 19 and is wavelength-converted, and the light receiving element 3 does not receive the wavelength-converted light. Further, the light receiving element 3 is configured not to receive the wavelength range of the light emitted by the light emitting element 4 among the light 13 incident from the outside. That is, the light receiving element 3 of FIG. 4 is configured to receive light in a wavelength range excluding the wavelength range of the light wavelength-converted by the phosphor 19 and the wavelength range of the light emitted by the light emitting element 4. .

<Fourth Embodiment>
In the first to third embodiments, the case where one optical sensor 1 is used is shown, but as shown in FIG. It may be used as an optical communication device capable of optical communication using light and infrared light. In this case, the light emitting element 4 of the first optical sensor 20 on one side (lower side in FIG. 5) emits infrared light 22, and the light receiving element 3 of the second optical sensor 21 on the other side (upper side in FIG. 5) By receiving the infrared light 22 of the first photosensor 20, the light emitting element 4 of the second photosensor 21 emits visible light 23, and the visible light 23 from the second photosensor 21 is transmitted to the first photosensor 20. light receiving element 3 receives the light.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

In the above embodiment, the optical sensor 1 provided with one light emitting element 4 for the light receiving element 3 is shown, but it may be implemented by providing a plurality of light emitting elements (any number of two or more). . Alternatively, the light receiving element may be configured to receive light in a plurality of wavelength ranges.

DESCRIPTION OF SYMBOLS 1... Optical sensor 2... Substrate 2A... Upper surface 3... Light receiving element 3A... Light receiving surface 4... Light emitting element 4A... Light emitting surface 4L... Optical axis 5... Sealing resin 6, 7, 8... Bonding wire, 9... Wavelength range of light receiving element (sensitivity wavelength range), 10... Wavelength range of light emitting element (light emission wavelength range), 11... Wavelength range of light receiving element (sensitivity wavelength range), 12... Wavelength range of light emitting element ( Emission wavelength range), 13, 14, 15, 17... light, 16... reflector, 18... optical filter, 19... phosphor, 20... first optical sensor, 21... second optical sensor, 22, 23... light

Claims (1)

A light-emitting element that emits light in a direction away from the light-receiving element is mounted on the light-receiving surface of the light-receiving element for receiving light, and is integrated into a package,
The light-receiving element is configured to be larger than the light-emitting element so that the light-receiving surface is exposed, and is set to a wavelength range in which the light emitted by the light-emitting element cannot be received,
The light-emitting element is configured to turn on, turn off, or change the lighting state when the light-receiving element receives incident light ,
The wavelength range of the light emitting element is 380 nm to 440 nm, the peak wavelength of the light emitting element is 400 nm,
The optical sensor, wherein the light receiving element has a wavelength range of 400 nm to 1100 nm and a peak wavelength of 1000 nm .

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