Optical sensor

Abstract

To provide an optical sensor having stable light shielding performance.SOLUTION: A copper foil pattern is disposed on a straight line connecting the light emitting means and the light receiving means on the surface of the substrate, the copper foil pattern is disposed with a space with respect to a surrounding copper foil pattern, the space is disposed in the first region and the second region, and the space disposed in at least one of the first region and the second region is shielded from light by a light shielding member disposed so as to be in contact with the substrate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a stray light suppression method for improving the detection accuracy of an optical sensor by suppressing the generation of stray light through a substrate. [Background technology]

[0002] In an optical sensor in which light is irradiated onto an irradiated portion from a light emitting means mounted on a substrate and reflected light is received by a light receiving means, unintended light from the light emitting means may enter the light receiving means via the substrate (hereinafter referred to as stray light). If stray light enters the light receiving means, there is a risk that detection accuracy will deteriorate. As a countermeasure against stray light entering the light receiving means, a method has been considered in which the entire surface of the substrate is covered with black resist or light-shielding paint (silk), as in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-354832 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method of covering the entire surface of the substrate with black resist or light-shielding paint (silk) as in Patent Document 1, if there are unevenness in the formed black resist or light-shielding paint, light may pass through the uneven parts, which may not be an adequate measure against stray light.

[0005] In view of the above problems, an object of the present invention is to provide an optical sensor having stable light-blocking performance. [Means for solving the problem]

[0006] In order to achieve the above object, the optical sensor of the present invention comprises a light emitting means for emitting light toward an object to be irradiated, a light receiving means for receiving light that has been emitted from the light emitting means and then reflected by the object to be irradiated, a substrate on which the light emitting means and the light receiving means are mounted on the same surface, and a housing that is installed on the surface of the substrate on which the light emitting means is mounted, and that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which light emitted from the light emitting means passes and a second hole portion through which light reflected by the object to be irradiated passes, and An optical sensor having a first region which is the region projected onto the surface of the substrate and a second region which is the region where the second space is projected onto the surface of the substrate, wherein a copper foil pattern is arranged on a straight line connecting the light-emitting means and the light-receiving means on the surface of the substrate, the copper foil pattern is arranged with a space between it and the surrounding copper foil patterns, the space is arranged in the first region and the second region, and the space arranged in at least one of the first region and the second region is shielded by a light-shielding member arranged to contact the substrate.

[0007] In order to achieve the above object, another optical sensor of the present invention includes a light emitting means for emitting light toward an object to be irradiated, a light receiving means for receiving light that has been emitted from the light emitting means and then reflected by the object to be irradiated, a substrate on which the light emitting means and the light receiving means are mounted on the same surface, and a housing that is installed on the surface of the substrate on which the light emitting means is mounted, and that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which the light emitted from the light emitting means passes and a second hole portion through which the light reflected by the object to be irradiated passes, and and a second area where the second space is projected onto the surface of the substrate, wherein a first copper foil pattern for passing current to the light-emitting means and a second copper foil pattern for passing current to the light-receiving means are arranged on a straight line connecting the light-emitting means and the light-receiving means on the surface of the substrate, the first copper foil pattern and the second copper foil pattern are arranged with a space between them, and the part of the housing that separates the first space and the second space is arranged so that it overlaps with the space when viewed in a direction perpendicular to the surface of the substrate, so that the space is not arranged in at least one of the first area and the second area. [Effects of the Invention]

[0008] As described above, according to the present invention, it is possible to provide an optical sensor having stable light blocking performance. [Brief explanation of the drawings]

[0009] [Figure 1] Schematic diagram of an optical sensor in Example 1 [Figure 2] Wiring diagram on the board in Example 1 [Figure 3] Schematic diagram of an optical sensor in Example 2 [Figure 4] Wiring diagram on the board in Example 2 [Figure 5] Wiring diagram on the board in a modified example of the second embodiment DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0011] First, Figure 1 shows a schematic diagram (side view) of the optical sensor in this implementation. The numbers in the figure represent an LED (Light Emitting Diode) 100, which is a light-emitting means; a PD (Photo Diode) 110, which is a light-receiving means; a substrate 105 on which the LED 100 and PD 110 are mounted on the same surface; an aperture (housing) 120 that narrows the light emitted from the LED 100 and received by the PD 110; and a reflector (irradiated object) 140 that reflects the light from the LED 100. The aperture 120 is installed on the surface of the substrate 105 on which the LED 100 and PD 110 are mounted. As an example, the substrate 105 is an inexpensive paper phenolic substrate. The light emitted from the LED 100 forms an optical path A narrowed by the aperture 120. Of the light along optical path A, light emitted from a first hole in a first space within aperture 120 is reflected by reflector 140, and of the reflected light, light along optical path B that passes through a second hole in aperture 120 is received by PD 110 in the second space. Because aperture 120 is made of a material with high light-blocking properties, there is very little light that penetrates aperture 120 from the inside and leaks out, and very little light that penetrates aperture 120 from the outside and enters.

[0012] An LED copper foil pattern 101, which is a first copper foil pattern for supplying power by energizing the LED 100, is wired on the substrate 105. The LED copper foil pattern 101 and a surrounding copper foil pattern 115 are wired with an LED wiring space 102 between them. Similarly, a PD copper foil pattern 111, which is a second copper foil pattern for supplying power and signals by energizing the PD 110, is wired with a distance of 112 between it and the surrounding copper foil pattern 115. Furthermore, a plurality of wiring copper foil patterns 114 for operating peripheral circuits are wired with a distance of 116 between them and the surrounding copper foil pattern 115 and a light-shielding copper foil pattern 117, which is a third copper foil pattern. Depending on the wiring method, the LED copper foil pattern 101 and the PD wiring pattern may be wired between the LED 100 and the PD 110, like the wiring copper foil pattern 114. The area where the first space is projected onto the surface of the substrate 105 and where the aperture 120 does not contact the substrate 105 is referred to as a first area 121, which is an apertureless area. The area where the second space is projected onto the surface of the substrate 105 and where the aperture 120 does not contact the substrate 105 is referred to as a second area 122, which is an apertureless area. In other words, the optical sensor has a first area and a second area. The LED copper foil pattern 101, the PD copper foil pattern 111, and the wiring copper foil pattern 114 are made of metal and do not transmit light. On the other hand, the LED wiring space 102, the PD wiring space 112, and the wiring space 116 are not covered with a highly light-blocking material and therefore easily transmit light emitted from the LED.

[0013] Most of the light emitted from LED 100 follows optical path A or optical path B. However, as shown by optical path C, some of the light passes through wiring space 116, which is easily transparent, and is diffusely reflected inside substrate 105, emitted from wiring space 116, and may be received by PD 110 as stray light.

[0014] Figure 2 shows a wiring diagram (Top View) of the optical sensor on the board. Figure 1 shows cross section A of Figure 2. Outside the first region 121 and the second region 122, the board and the aperture are in contact, so very little light enters from the outside.

[0015] Here, the wiring copper foil pattern 114 may be electrically connected to the LED copper foil pattern 101, the PD copper foil pattern 111, and the surrounding copper foil pattern 115, or may be a copper foil pattern that is not electrically connected.

[0016] Furthermore, the light-shielding copper foil pattern 117 provided between the LED 100 and the PD 110 may be a copper foil pattern that is not electrically connected to the LED copper foil pattern 101, the PD copper foil pattern 111, the wiring copper foil pattern 114, or the surrounding copper foil patterns 115.

[0017] First, we will explain measures against stray light in the first region 121. The first region 121 includes the LED wiring space 102 and the wiring space 116. There is a possibility that light emitted from the LED 100 may enter the interior of the substrate 105 via the LED wiring space 102 and the wiring space 116. The wiring space 116 is located on a straight line between the LED 100 and the PD 110, and stray light entering from the wiring space 116 has a significant impact on false detection and deterioration of accuracy in the PD 110. Therefore, in this patent, a light-blocking member 181 is placed above the wiring space 116 in the first region 121 to suppress the effects of stray light.

[0018] Next, the second area 122 includes the PD wiring space 112 and the wiring space 116. In both areas, light emitted from the LED 100 may enter the inside of the substrate 105. As already explained, the wiring space 116 has a large impact on false detection and deterioration of accuracy in the PD 110. Therefore, in this patent, a light-shielding member 181 is disposed above the wiring space 116 in the second area 122 to suppress the effects of stray light.

[0019] The light blocking member 181 may be any material with high light blocking properties, such as a light blocking tape or black silk.

[0020] As described above, by arranging a light-shielding member in the wiring space 116 of the first region 121 and the second region 122, which is a source of stray light, it is possible to suppress false detections and deterioration of accuracy due to stray light with a minimum of additional members.

[0021] The light blocking member 181 may also be configured to cover the wiring space 116 in either the first region 121 or the second region 122 .

[0022] The optical sensor of this embodiment may be used as, for example, a sensor for detecting a sheet in an image forming apparatus. [Example]

[0023] In this embodiment, as shown in Figures 3 and 4, the aperture 120 also serves as a light-blocking member, eliminating the wiring space 116 within the first region 121 and the second region 122, thereby suppressing false detection and deterioration of accuracy due to stray light.

[0024] An LED copper foil pattern 101, which is a first copper foil pattern for supplying power by energizing the LED 100, is wired on the substrate 105. The LED copper foil pattern 101 and a surrounding copper foil pattern 115 are wired with an LED wiring space 102 between them. Similarly, a PD copper foil pattern 111, which is a second copper foil pattern for supplying power and signals by energizing the PD 110, is wired with an interval of PD wiring space 112 between it and the surrounding copper foil pattern 115. In addition, a plurality of wiring copper foil patterns 114 for operating peripheral circuits are wired with an interval of wiring space 116 between them and the surrounding copper foil pattern 115 and a light-shielding copper foil pattern 117, which is a third copper foil pattern.

[0025] Here, the wiring copper foil pattern 114 may be electrically connected to the LED copper foil pattern 101, the PD copper foil pattern 111, and the surrounding copper foil pattern 115, or may be a copper foil pattern that is not electrically connected.

[0026] Furthermore, the light-shielding copper foil pattern 117 provided between the LED 100 and the PD 110 may be a copper foil pattern that is not electrically connected to the LED copper foil pattern 101, the PD copper foil pattern 111, the wiring copper foil pattern 114, or the surrounding copper foil patterns 115.

[0027] 3 shows a schematic diagram (side view) of the configuration of the second embodiment, which corresponds to cross section B in FIG. 4. The same parts as those in the first embodiment are given the same reference numerals and their explanations will be omitted. When viewed in a direction perpendicular to the surface of the substrate 105, the part of the aperture 120 that separates the first space and the second space is arranged to overlap with the wiring space 116.

[0028] 4 shows a wiring diagram (Top View) on the board when viewing the optical sensor of Example 2. The wiring space 116 is arranged on a straight line between the LED 100 and the PD 110, but is not located in the first area 121 or the second area 122. Therefore, the light emitted from the LED 100 does not enter the wiring space 116, and false detection and deterioration of accuracy in the PD 110 due to stray light can be suppressed.

[0029] Furthermore, as shown in FIGS. 5(a) and 5(b), the wiring space 116 may be configured to be in contact with the aperture 120 in at least one of the first region 121 and the second region 122, which also has the effect of suppressing stray light.

[0030] As described above, by devising the shape of the aperture 120 and the wiring position of the wiring space 116, it is possible to suppress erroneous detection and deterioration of accuracy due to stray light without adding a new light-blocking member compared to the first embodiment.

[0031] The optical sensor of this embodiment may be used as, for example, a sensor for detecting a sheet in an image forming apparatus.

[0032] [Note] The disclosure of the present embodiment also includes the following configuration examples and method examples.

[0033] (Item 1) a light emitting means for emitting light toward an object to be irradiated; a light receiving means for receiving light that is emitted from the light emitting means and then reflected by the object to be irradiated; a substrate on which the light emitting means and the light receiving means are mounted on the same surface; a housing that is installed on a surface of the board on which the light emitting means is mounted, that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which light emitted from the light emitting means passes and a second hole portion through which light reflected by the irradiated object passes; Equipped with a first region on a surface of the substrate, the first space being a region where the first space is projected onto the surface of the substrate; and a second region on a surface of the substrate, the second space being a region where the second space is projected onto the surface of the substrate. an optical sensor in which a copper foil pattern is disposed on a straight line connecting the light emitting means and the light receiving means on the surface of the substrate, and the copper foil pattern is disposed with a space between it and surrounding copper foil patterns; the spaces are arranged in the first area and the second area, An optical sensor characterized in that the space disposed in at least one of the first region and the second region is shielded from light by a light-shielding member disposed in contact with the substrate.

[0034] (Item 2) Item 1, an optical sensor according to item 1, An optical sensor characterized in that a copper foil pattern arranged between the space arranged in the first region and the space arranged in the second region is not electrically connected to the light emitting means and the light receiving means.

[0035] (Item 3) The optical sensor according to items 1 and 2, The optical sensor is characterized in that the light-shielding member is a tape having light-shielding properties.

[0036] (Item 4) The optical sensor according to items 1 to 3, The optical sensor is characterized in that the light-shielding member is silk having light-shielding properties.

[0037] (Item 5) a light emitting means for emitting light toward an object to be irradiated; a light receiving means for receiving light that is emitted from the light emitting means and then reflected by the object to be irradiated; a substrate on which the light emitting means and the light receiving means are mounted on the same surface; a housing that is installed on a surface of the board on which the light emitting means is mounted, that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which light emitted from the light emitting means passes and a second hole portion through which light reflected by the irradiated object passes; Equipped with a first region on a surface of the substrate, the first space being a region where the first space is projected onto the surface of the substrate; and a second region on a surface of the substrate, the second space being a region where the second space is projected onto the surface of the substrate. an optical sensor in which a first copper foil pattern for supplying current to the light-emitting means and a second copper foil pattern for supplying current to the light-receiving means are arranged on a straight line connecting the light-emitting means and the light-receiving means on the surface of the substrate, and the first copper foil pattern and the second copper foil pattern are arranged with a space between them; An optical sensor characterized in that the part of the housing that separates the first space and the second space is positioned so as to overlap with the space when viewed in a direction perpendicular to the surface of the substrate, so that the space is not located in at least one of the first area and the second area.

[0038] (Item 6) Item 5. The optical sensor according to item 5, An optical sensor characterized in that a third copper foil pattern that is not electrically connected to the first copper foil pattern and the second copper foil pattern is provided in the space.

[0039] (Item 7) The optical sensor according to items 1 to 6, The optical sensor is characterized in that the substrate is a paper phenol substrate. [Explanation of symbols]

[0040] 100 LED 101 LED wiring pattern 102 LED wiring space 105 PCB 110PD 111 PD copper foil pattern 112 PD wiring space 114 Wiring copper foil pattern 115 Surrounding copper foil pattern 116 Wiring space 117 Light-shielding copper foil pattern 120 aperture 121 First Area 122 Second Area 140 Reflector

Claims

1. a light emitting means for emitting light toward an object to be irradiated; a light receiving means for receiving light that is emitted from the light emitting means and then reflected by the object to be irradiated; a substrate on which the light emitting means and the light receiving means are mounted on the same surface; a housing that is installed on a surface of the board on which the light emitting means is mounted, that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which light emitted from the light emitting means passes and a second hole portion through which light reflected by the irradiated object passes; Equipped with a first region on a surface of the substrate, the first space being a region where the first space is projected onto the surface of the substrate; and a second region on a surface of the substrate, the second space being a region where the second space is projected onto the surface of the substrate. an optical sensor in which a copper foil pattern is disposed on a straight line connecting the light emitting means and the light receiving means on the surface of the substrate, and the copper foil pattern is disposed with a space between it and surrounding copper foil patterns; the spaces are arranged in the first region and the second region, An optical sensor, characterized in that the space disposed in at least one of the first region and the second region is shielded from light by a light shielding member disposed in contact with the substrate.

2. 2. The optical sensor according to claim 1, wherein a copper foil pattern disposed between the space disposed in the first region and the space disposed in the second region is not electrically connected to the light emitting means and the light receiving means.

3. 2. The optical sensor according to claim 1, wherein the light-shielding member is a tape having light-shielding properties.

4. 2. The optical sensor according to claim 1, wherein the light-shielding member is silk having light-shielding properties.

5. a light emitting means for emitting light toward an object to be irradiated; a light receiving means for receiving light that is emitted from the light emitting means and then reflected by the object to be irradiated; a substrate on which the light emitting means and the light receiving means are mounted on the same surface; a housing that is installed on a surface of the board on which the light emitting means is mounted, that forms a first space that includes the light emitting means and a second space that includes the light receiving means, and that has a first hole portion through which light emitted from the light emitting means passes and a second hole portion through which light reflected by the irradiated object passes; Equipped with a first region on a surface of the substrate, the first space being a region where the first space is projected onto the surface of the substrate; and a second region on a surface of the substrate, the second space being a region where the second space is projected onto the surface of the substrate. an optical sensor in which a first copper foil pattern for supplying current to the light-emitting means and a second copper foil pattern for supplying current to the light-receiving means are arranged on a straight line connecting the light-emitting means and the light-receiving means on the surface of the substrate, and the first copper foil pattern and the second copper foil pattern are arranged with a space between them; An optical sensor characterized in that the part of the housing that separates the first space and the second space is positioned so that it overlaps with the space when viewed in a direction perpendicular to the surface of the substrate, so that the space is not located in at least one of the first area and the second area.

6. 6. The optical sensor according to claim 5, wherein a third copper foil pattern not electrically connected to the first copper foil pattern and the second copper foil pattern is provided in the space.

7. 7. The optical sensor according to claim 1, wherein the substrate is a paper phenol substrate.

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