TW201341832A - Reflection light sensor - Google Patents

Abstract

To provide a reflection light sensor performing a measurement based on a triangulation principle, which can easily reduce a noisy light effect on a light-receiving element without extra cost. In a two-partition light-receiving element 1 inserted in a distance-setting reflection light sensor, a light-receiving area of a Near-side light-receiving element 1N, which receives a reflection light from a place comparatively near the sensor, gradually decreases as the distance from an interface with a Far-side light-receiving element 1F increases. Because the reflection light with high intensity in wide range enters the Near-side light-receiving element 1N, the light-receiving quantity required for detection can be ensured even if the light-receiving area decreases. Further, the quantity that the noisy light enters can be reduced by decreasing the light-receiving area.

Description

Reflective light sensor

The present invention relates to a reflective light sensor that emits light by a light projecting element and that receives light reflected from the object to be detected by the light receiving element, and then uses the light received by the light receiving element. The amount of received light is measured according to the principle of triangulation.

As such a photosensor, for example, there is a distance setting type photo sensor that uses a two-divided light receiving element or a PSD as a light receiving element, and performs a pair of received light amount signals output from the light receiving element. After the difference operation, the difference level is compared with a predetermined threshold value, thereby detecting an object located at the reference point. Also, an object that reaches a predetermined reference position or a person who measures the displacement of the object is detected. Further, there is also a distance measuring type sensor which uses a charge storage type light receiving element such as a CMOS or a CCD to generate a light distribution amount data over the entire area of the light receiving surface, according to a peak in the distribution The position of the value, the distance to the object is measured.

Fig. 11 is a diagram showing the basic configuration of an optical system common to these reflective photosensors together with the detection principle.

In Fig. 11, reference numeral 1 denotes a light-receiving element 1, and reference numeral 2 denotes a light-emitting element in which a light projecting portion is incorporated. The light-receiving element 1 has a direction (in FIG. 11 Down direction) Long light receiving surface. The light emitted from the light projecting element 2 is emitted to the outside through the light projecting lens L2, and a part of the light reflected by the detection object SB is incident on the light receiving element 1 via the light receiving lens L1. Since the imaging position of the reflected light changes depending on the distance from the light receiving lens L2 to the detection target SB, the light receiving element 1 adjusts the position or posture so that the longitudinal direction coincides with the changing direction of the imaging position of the reflected light.

When the detection target SB is located at point A in FIG. 11 , the reflected light from the detection target SB is formed at the center position in the longitudinal direction of the light-receiving element 1 (the dotted line in the light-receiving element 1 in FIG. 11 is shown). The location of the location). As the detection target SB moves forward from the point A, the imaging position of the reflected light moves from the center position to the lower side in FIG. 11; as the detection object SB moves rearward from the point A, the incident position of the reflected light is from the center. Move to the top of Figure 11.

Hereinafter, point A is referred to as a reference point. In the light-receiving surface of the light-receiving element 1, the direction in which the image-forming position of the reflected light is moved when the object to be detected SB approaches the sensor is referred to as the "Near side", and the object to be detected SB is moved away from the sensor. The direction in which the imaging position of the reflected light is moved is referred to as "Far side". In the two-divided light-receiving element, the light-receiving element on the near side is referred to as a "Near-side element", and the light-receiving element on the Far side is referred to as a "Far-side element".

As a conventional example of a reflective photosensor, Patent Document 1 discloses a sensor configured to mount a light projecting portion including a light projecting element and a light projecting lens in the same clamp portion. The light receiving unit that is configured to divide the light receiving element and the lens is housed in the same casing (see paragraphs 0026 to 0027, Fig. 2, and the like). Further, in Patent Document 1, it is described In the detection principle described above, the distance or displacement to the detection target (workpiece) is detected using the differential signal of the received light amount of each light receiving element (see paragraphs 0848 to 0051, Fig. 6 to Fig. 8, etc.).

Next, Patent Document 2 is cited as a document related to the features of the present invention described below.

The person disclosed in Patent Document 2 uses a position detecting sensor of the PSD. In this document, it is described that the plate-shaped light-shielding body is slidably provided in order to solve the problem that the detection accuracy is lowered by the light received by the distance-dependent light (normal reflection light of the light of the light beam extending to the hem, etc.). On the front side of the light-receiving element (PSD), the light-shielding body shields all of the light-receiving surfaces other than the moving range of the imaging light (see paragraphs 0013, 0015, 0026 to 0031, 1st, 7th, 8th, and 8th). 10 maps, etc.).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-33162

[Patent Document 2] Japanese Patent No. 3677868

Generally, when a light receiving element emits strong light, noise called loose noise is generated. The scattered noise is superimposed on the received light amount signal as white noise when processed by the light receiving circuit. In particular, in the case of a reflective photosensor using a triangulation, it is necessary to correspond to the range of movement of the reflected light. Since a light-receiving element having a wide light-receiving surface is used, the influence of the noise component on the received light signal becomes strong, and may be The test has an adverse effect.

Fig. 12 is a view showing a light-receiving amount signal obtained when the reflected light SL of the detection target is incident on the light-receiving element 1 and a light-receiving amount signal in a state where the noise light NL is incident (Fig. 12 (1) )(2)). As shown in the graph below, when the noise light NL caused by the white light is incident on the reflected light SL, fine vibration is generated in the received light amount signal due to white noise. When the vibration becomes large, a malfunction may occur in the detection operation of the sensor.

Fig. 13 is a view showing an example of signal processing in which a two-divided light-receiving element is used as a photodetector of the light-receiving element 1, and an example of a malfunction caused by the influence of noise light is schematically indicated. Further, in Fig. 13, the light receiving amount signal of the Near side element is P _N , and the light receiving amount signal of the Far side element is P _F . P _N -P _F

First, refer to Fig. 13 (1) on the left side to explain the signal processing method. In this example, the difference between the received light amount difference signal P _N -P _F and the addition signal P _N +P _{F is} compared with the two threshold values which are different from each other. Hereinafter, the threshold value at which the value is relatively high is referred to as a conduction threshold, and the threshold at which the value is relatively low is referred to as a non-conduction threshold. The comparison result of the differential signals P _{N -} P _F is output as a differential control signal, and the comparison result of the addition signals P _N + P _F is output as an addition control signal.

In the signal processing of the differential signal, when the differential signal is higher than the conduction threshold, the differential control signal is set to the on state, and when the differential signal is lower than the non-conduction threshold, the differential control signal is set to not On state. The same applies to the signal processing of the addition signal. When the addition signal is higher than the conduction threshold, the addition control signal is set to the on state, and when the addition signal is lower than the non-conduction threshold, The addition control signal is set to a non-conducting state.

While both the differential control signal and the addition control signal are in an on state, it is determined that the detection target SB is located in front of the reference point. When the detection target SB moves in a direction away from the position before the reference point, the differential signal changes from a state higher than the conduction state to a state lower than the non-conduction threshold value, and the differential control signal changes from the conduction state to the non-conduction state. On state. Further, when the detection target SB moves to a position far from the reference point, the addition signal changes from a state higher than the conduction state to a state lower than the non-conduction threshold value, and the addition control signal changes from the conduction state to the non-conduction state. On state.

Contrary to the above, when the detection target SB moves from the far side in the direction approaching the reference point, first, the addition control signal changes from the non-conduction state to the on state, and then the differential control signal changes from the non-conduction state to the on state.

When a light-receiving amount signal with a noise component as shown in Fig. 12 (2) is generated, the same vibration occurs in the differential signal or the addition signal. When the amplitude of the noise component of the differential signal or the addition signal is greater than the difference between the conduction threshold and the non-conduction threshold, as shown in FIG. 13 (2), the conduction or non-conduction occurs in the differential control signal or the addition control signal. Switching phenomenon (vibration) at small intervals.

The influence of the white noise is not limited to the two-divided light-receiving element, and erroneous detection may occur in the same manner in a reflective photosensor using another type of light-receiving element.

Further, in the light receiving element, the dynamic range is fixed, and if light exceeding the maximum value of the range is incident, the amount of received light indicated by the received light amount signal becomes saturated. . Therefore, when a strong noise light is incident and the received light amount signal becomes saturated, a signal reflecting the incident position of the reflected light cannot be obtained, and a detection error occurs.

In order to avoid the influence of such noise light, a lens having a function of cutting off light in the near-infrared band or an optical filter that cuts light in the near-infrared band has been used as a countermeasure for a light-receiving lens. However, since the optical element of the wavelength type is expensive, the cost is increased.

As a method of not increasing the cost, there is a method of reducing the amplitude of the noise component by reducing the gain of the light-receiving signal in the range of the detection-free detection (refer to Fig. 14 (A-1), (A-2). )). However, when the gain is lowered, the amplitude of the entire received light amount signal is also suppressed, and the degree of change of the signal is alleviated, so that the responsiveness is deteriorated.

(B) is a differential signal of the received light amount signal (signal of Fig. 14 (A-1)) in a state where the gain of the received light amount is not reduced by the sensor using the two-divided light receiving element, and The differential signal of the received light amount signal (the signal of Fig. 14 (A-2)) when the gain is lowered is targeted, and the change indicates the change in the vicinity of the threshold. As shown in Fig. 14(B), when the gain is lowered, since the degree of change of the signal becomes gentle, the range of the signal obtained at the level between the conduction threshold and the non-conduction threshold is expanded, which is inferior. The distance becomes longer and the responsiveness decreases.

The present invention has been made in view of the above problems, and a reflective photosensor measured according to the principle of triangulation has an object of improving the detection accuracy by easily reducing the influence of noise light on the light receiving element without increasing the cost.

The present invention is applied to a reflective photosensor which is a light projecting element that projects light and a reflected light that is received by an object that receives light from a light projecting element by receiving light in one direction. The light-receiving light-receiving element is provided in such a relationship that the imaging position of the reflected light in the longitudinal direction of the light-receiving surface changes in accordance with the distance of the object that generates the reflection.

According to a first aspect of the invention, the light receiving element is configured such that when the object that reflects the light from the light projecting element approaches the sensor, the light receiving area that is gradually narrowed in a direction in which the image forming position of the reflected light is moved is accepted. Light.

Hereinafter, this feature will be described using Fig. 15.

Fig. 15 shows a state in which the reflected light (the images of the reflected light) SP _A , SP _B , and SP _C of the light receiving element 1 are formed by the reflected light from the respective points A, B, and C shown in Fig. 11 .

In the case where the object to be detected is in the vicinity of the point A of the reference point, the center of the light receiving point SP _A is substantially equal to the center line L which divides the longitudinal direction of the light receiving element, so that it is divided by the center line L of the light receiving surface. The amount of light received in the left and right areas is substantially equal.

Further, from the relationship between the light-receiving points SP _B and SP _{C in} FIG. 15 and the points _B and _C of the foregoing eleventh diagram, it is known that when the detection target SB approaches the sensor, it is far from the detection target SB. Compared with the sensor, the degree of movement of the light receiving point is greater, and the diameter of the light receiving point is also greatly expanded.

As described above, the closer the imaging position of the reflected light is to the area on the near side, the larger the area of the light receiving point. Further, since the intensity of the reflected light incident on the detection object SB is closer to the sensor, the region closer to the near side than the center line L (the region on the left side in Fig. 15), even if not Accepting all of the reflected light that can be injected also ensures the amount of light required for detection. On the other hand, since the noise light has a possibility of entering the entire light-receiving surface without selecting a position, if the light-receiving area on the near side is reduced, the incident amount of the noise light can be reduced only in accordance with the removed light-receiving area. The amount of area.

According to the first aspect of the invention, the width of the light receiving region is gradually narrowed as the near side of the strongly reflected light is incident on the near side. According to this configuration, the area of the surface from which the reflected light from the position close to the sensor receives light is greatly reduced. However, since the reflected light from the close range is irradiated over a wide range, even a narrow light receiving area occurs. The possibility of being missed by light is also low. Further, since the amount of reflected light is increased, even if the ratio of the light that is blocked is increased, the amount of received light required for detection can be ensured. On the other hand, since the incident light amount of the noise light is greatly reduced in accordance with the reduction of the light receiving region, the noise component in the light receiving signal is drastically reduced, and malfunction can be prevented.

As an embodiment of the first invention, it is as follows.

First, in the first embodiment, in the front of the light receiving element, the case where the object reflecting the light from the light projecting element is brought close to the sensor has a width which gradually narrows in the direction in which the image forming position of the reflected light moves. The shielding member of the opening of the shape shields a part of the reflected light that can enter the light receiving surface by the shielding member. In other words, instead of receiving the size or shape of the light surface itself, a part of the light receiving surface is shielded by the light shielding member and the opening portion in front of the light surface, thereby reducing the light receiving region.

Further, Patent Document 2 listed above discloses a technical concept of preventing the entrance of noise light by shielding a part of the light receiving surface. but According to the invention described in Patent Document 2, the specular light from the object is used as the noise light, and the range of the incident light is conceivable, and the intended range is shielded from light. On the other hand, in the present invention, it is possible to reduce the incident range of the light, and to reduce the influence of the disturbing light which is likely to be incident on the entire light-receiving surface as a part of the light-shielding range in which the light required for detection is incident. Therefore, the technical concept is largely different from Patent Document 2.

Here, referring to Fig. 15, according to the characteristics of the optical system of the reflective sensor, the degree of movement of the light receiving point on the Far side on the light receiving surface of the light receiving element is smaller than that of the light receiving point on the Near side. After a certain location, it becomes a state in which the light receiving point is almost immovable. In the example of Fig. 15, the outer side of the limit position generated by the light receiving point SP _C is a wasteful area in which reflected light is not incident.

Therefore, if the length of the light-receiving surface is set in advance so that the vicinity of the edge on the Far side of the light-receiving surface of the light-receiving element becomes the limit position of the light-receiving point on the Far side, the wasted area on the Far side can be reduced, and the light-shielding member can also be used. The amount of incident light of the noise light can be reduced, so that the noise component can be greatly reduced.

However, when it is difficult to adjust the length of the light-receiving surface, and a wasteful area is always generated on the Far side, the shielding member and the light-receiving surface of the light-receiving element are opposed to each other, and the area of the opening to the Far side is set to be free of ratio. The range outside the extreme position where the reflected light is imaged may be. In this way, the wasted area on the Far side is shielded by the light shielding member, and the possibility that the noise component increases due to the entrance of the wasted light to the wasted area disappears.

A form of the concept of the lower order of the first embodiment The surface of the light-receiving element is applied to the clamp portion of the light-receiving element to act as a shielding member, and the light-receiving window formed on the surface for guiding the reflected light to the light-receiving element acts as an opening. That is, the area of the light receiving region can be easily adjusted by working under the shape of the light receiving window of the optical jig.

In another aspect of the second aspect of the first embodiment, the shielding member is provided between the surface located before the light receiving element and the light receiving element in the jig portion incorporated in the light receiving element. Further, a light receiving window larger than the opening of the shielding member is formed on the surface located before the light receiving element. According to the present embodiment, the reflected light is transmitted through the light receiving window on the front surface of the light receiving element, and a part of the shielding member provided between the front surface and the light receiving element is shielded from light, thereby adjusting the light receiving area of the light receiving element. Area.

In the reflective photosensor according to the second embodiment, the light-receiving surface of the light-receiving element is divided into a region covered with a resin having a light-shielding property and a region not covered, and the region not covered with the resin. The shape is set such that the object that reflects the light from the light projecting element approaches the sensor gradually narrows in width in the direction in which the image forming position of the reflected light moves. In this manner, the area of the light receiving region of the light receiving element can be adjusted by processing the light receiving element itself.

In the second embodiment, the length of the light-receiving surface is adjusted so that the extreme position of the light-receiving point on the Far side is preferably in the vicinity of the edge of the Far side. However, if it is not possible, the resin having the light-shielding property is covered. The area on the Far side is outside the limit position imaged by the reflected light.

In this way, it is possible to prevent the waste of the noise light from entering the non-reflected light. The area can reduce the amount of incident light of more noise light.

In the third embodiment, the light-receiving surface of the light-receiving element has a shape in which the object that reflects the light from the light-emitting element approaches the sensor, and the width gradually decreases in the direction in which the image-forming position of the reflected light moves. That is, it is made to reduce the light receiving area by the shape of the light receiving element itself.

In the third embodiment, it is preferable that the vicinity of the edge of the region on the Far side of the length of the light-receiving surface is the limit position at which the reflected light is imaged. In this way, if the width of the area of the Far is narrowed, the wasted area in which the reflected light does not enter can be greatly reduced, and the amount of incident light of the noise light can be further reduced.

In the reflection type photosensor of the second aspect of the invention, the two-divided light-receiving element is used as the light-receiving element, and the detection signal is output based on the difference value of the amount of received light between the two light-receiving elements, and is received by the two-divided light-receiving element. The Near side element of the reflected light from the position relatively close to the sensor is received in the light receiving area whose width gradually narrows away from the boundary of the Far side element that receives the reflected light from the position relatively far from the sensor. Light.

In the two-divided light-receiving element, since the range of the incident light of the reflected light to the near-side element is increased and the intensity is increased, even if the reflected light that can be incident on all of the near-side elements 1N is not received, the detection is required. The amount of light received. Further, since the noise light system has a possibility of entering the entire surface of each light-receiving element without selecting a position, if the light-receiving area of the near-side element is reduced, the amount of incident light of the noise light can be reduced only by the light-receiving light that is removed. The amount of area of the area.

The second invention focuses on the above characteristics and is divided into two light-receiving In the element, the light-receiving area on the near side where the strongly reflected light is incident is made to gradually narrow in width as it goes away from the boundary with the Far side. According to this configuration, the area of the surface from which the reflected light from the position close to the sensor receives light is greatly reduced. However, since the reflected light from the close range is irradiated over a wide range, even a narrow light receiving area occurs. The possibility of being missed by light is also low. Further, since the amount of reflected light is increased, even if the ratio of the light that is blocked is increased, the amount of received light required for detection can be ensured. On the other hand, since the incident light amount of the noise light is greatly reduced in accordance with the reduction of the light receiving region, the noise component in the light receiving signal is drastically reduced, and malfunction can be prevented.

In the reflective photosensor according to the embodiment of the second aspect of the invention, a shielding member having an opening portion having a shape that gradually narrows in width away from the boundary of the Far side element is provided in front of the light receiving element on the near side. By the shielding member, a part of the reflected light that can be incident on the Near side element itself is shielded. In other words, the light-receiving surface of the near-side element itself is not changed, but the light-receiving area is narrowed by shielding a part of the light-receiving surface with the front light-shielding member and the opening.

The shielding member is disposed at least in a range facing the near side element, but may be opposed to the entire front surface of the two-divided light receiving element. In this case, the opening portion extends over the boundary position between the light-receiving elements and extends to a partial range of the Far-side element, and the reflected light from the opening side of the Far-side element is farther from the reflected light than the near-side element. It becomes a state of being imaged on the Far side element. In this manner, since the reflected light that shields the Far side element by the shielding member does not enter the wasted area, the amount of incident light of the noise light can be greatly reduced.

In a mode in which the second-order light-receiving element is incorporated in the jig portion of the second-division light-receiving element, the surface located before the two-divided light-receiving element acts as a shielding member, and the reflected light is guided to the two-divided light-receiving element. The light receiving window formed on the surface functions as an opening. That is, the area of the light receiving region can be easily adjusted by working under the shape of the light receiving window of the optical jig.

In another aspect of the second-order concept of the first embodiment, the shielding member is provided between the surface located before the two-divided light-receiving element and the two-divided light-receiving element in the jig portion. Further, a light receiving window larger than the opening of the shielding member is formed on the surface located before the two-divided light receiving element. According to the present embodiment, the reflected light is transmitted through the light receiving window on the surface before the two-divided light receiving element, and a part of the shielding member provided between the front surface and the light receiving element is shielded from light, thereby adjusting the two-divided light receiving. The area of the light receiving area of the component.

In the third aspect of the invention, the type of the light-receiving element is not limited, and an optical filter having a transmittance gradually decreasing as the region away from the Far side is provided in front of the region on the near side of the light-receiving surface of the light-receiving element. In other words, the third invention is intended to reduce the amount of incident light of the noise light by reducing the amount of light incident on the near side in sections. In the area on the near side, the reflected light is greatly restricted from entering the position away from the Far side. However, since the intensity of the reflection system from the close distance is strong, even if the ratio of the light blocked by the optical filter is increased, the detection station can be ensured. The amount of light required.

On the other hand, since the amount of incident light of the noise light is greatly reduced, malfunction caused by the noise light can be prevented. Moreover, since the optical filter that does not select a wavelength is relatively inexpensive, it is possible to suppress an increase in cost.

When the length of the light receiving surface is adjusted so that the extreme position of the light receiving point on the Far side is in the vicinity of the edge on the Far side, the optical filter is provided at least in a range facing the front side of the area on the near side. . However, when the length of the light-receiving surface cannot be adjusted and the area of the waste outside the limit position of the light-receiving point becomes larger, the optical filter and the light-receiving surface of the light-receiving element are opposed to each other, and the contrast reflected light is incident. The range outside the extreme position may be set to a non-transmissive state. In this manner, it is possible to prevent the noise light from entering the position where the reflected light in the area on the Far side does not enter, and suppress the noise component overlapping the received light amount signal.

According to the present invention, it is possible to greatly reduce the amount of incident light of the noise light by limiting the amount of light received by the region on the near side where the diameter or intensity of the reflected light is sufficiently large in the range of the detection. .

Therefore, it is possible to prevent malfunction caused by noise light. Further, since the noise component is reduced, it is not necessary to reduce the gain of the amplification processing of the received light amount signal, and stable detection processing can be performed.

1‧‧‧Light-receiving components

1N‧‧‧Near side components

1F‧‧‧Far side components

2‧‧‧Lighting elements

3‧‧‧Clamping Department

4‧‧‧Shielding board

5‧‧‧Optical filter

10, 40‧‧‧ openings

11‧‧‧Shielding members

16‧‧‧ Sealing resin

30‧‧‧Clamp body

31‧‧‧ recess

100‧‧‧Receiving window

Fig. 1 is a view showing the relationship between a two-divided light-receiving element and a light-shielding member introduced by a photo-electrical sensor.

Fig. 2 is a graph showing the relationship between the addition signal from the light-receiving amount signals of the two light-receiving elements and the distance from the sensor to the detection target.

Fig. 3 is a graph showing the relationship between the position of the light receiving point generated by the two-divided light receiving element and the distance from the sensor to the object to be detected.

Fig. 4 is a view showing a modification of the opening of the light shielding member.

Fig. 5 is a front view and a perspective view of a jig portion of a two-divided light-receiving element to which the configuration of Fig. 1 is applied.

Fig. 6 is a front view and a side view of a jig portion of another embodiment to which the configuration of Fig. 1 is applied.

Fig. 7 is a view showing an example in which the configuration of Fig. 1 is applied, and the configuration of the CSP including the two-divided light receiving element is changed.

Fig. 8 is a view showing an example in which the configuration of Fig. 1 is applied and the shape of the two-divided light-receiving element is changed.

Fig. 9 is a view showing an example in which the amount of light incident on the two-divided light-receiving element is adjusted using an optical filter.

Fig. 10 is a view showing an example of a configuration of an optical system that satisfies Scheimpflug conditions and a light receiving point of a light receiving element formed in the optical system.

Fig. 11 is a view showing the basic configuration and detection principle of the optical system of the reflective photosensor.

Figure 12 is a graph illustrating the effect of the incoming light of the noise light on the received light signal.

Fig. 13 is a view showing a state in which a malfunction caused by noise occurs in signal processing of a distance-set photodetector according to a pattern diagram.

Fig. 14 is a diagram showing the relationship between the gain of the received light amount signal and the noise according to the pattern diagram.

Fig. 15 is a view showing an example in which the reflected light from each of the points A, B, and C in Fig. 11 is formed on the light receiving point of the two-divided light receiving element.

[Formation of the Invention]

Fig. 1 shows an application example of the present invention to a two-divided light-receiving element used in a distance-setting type reflective photosensor. In addition, hereinafter, the symbol 1 indicates the entirety of the two-divided light-receiving element, and the symbol 1N indicates the Near side element, and the symbol 1F indicates the Far side element. In the following description, the direction in which the Near side element 1N and the Far side element 1F are arranged is defined as the x direction, and the direction orthogonal to the x direction is referred to as the y direction. Further, the width in the x direction is referred to as a horizontal width, and the width in the y direction is referred to as a vertical width.

The two-divided light-receiving element 1 of the present embodiment is disposed in the same relationship as the one shown in FIG. 11 with respect to the light-emitting element 2. Since the detection principle is the same as that described in the column of the prior art, the respective light receiving points are denoted by the same reference numerals SP _A , SP _B , and SP _C as those in FIGS. 11 and 15 , and the description thereof will be omitted.

In front of the two-divided light-receiving element 1 of the present embodiment, a shielding member 11 having an opening 10 is provided. The opening portion 10 is expanded in the x direction to the full width of the Near side element 1N, and further expanded to a portion of the Far side element 1F across the boundary between the elements 1N and 1F. The range of the opening portion 10 in the y direction is set to a position close to the Far side element 1F and the Near side element 1N, and is set to include the entire width of the element, but the width of the opening in the y direction of the Near side element 1N is gradually increased. It is gradually narrowed away from the boundary with the Far side member 1F.

From the relationship between the respective light receiving points SP _A , SP _B , and SP _{C in} Fig. 1 and the opening 10, it is known that the reflected light from the reference point (point A) and the reflected light from the position farther than the reference point are almost all It passes through the opening 10 and is imaged as the light receiving points SP _A and SP _C .

On the other hand, in the reflected light from the position ahead of the reference point, light that blocks the light entering the Near side element 1N by the shielding member 11 is generated. Further, since the width of the opening portion 10 gradually narrows as it approaches the outer edge of the near side, the proportion of the light that is blocked is increased.

In addition, since the range of the incident light of the reflected light gradually increases as the object to be detected approaches the sensor, the range in which the reflected light passes is relatively wide with respect to the narrow portion of the width of the opening 10. Further, since the intensity of the reflected light from the close distance is strong, even if the ratio of the light entering the light is reduced, a sufficient amount of received light can be obtained.

2 is a sensor of a conventional type in which the shielding member 11 is not provided, and the addition amount P _{N of the} Near side element 1N and the light receiving amount P _F of the Far side element 1F are added in a manner of patterning according to the real side value. A graph of the level of the signal and the relationship from the sensor to the distance of the object being detected.

When the object to be detected than the reference point SB move forward, only to a state of the reflected light incident side Near 1N element, the light receiving system and the level of the amount of addition of 1N Near side element signal P _N consistent. When the detection target SB is located close to the sensor and cannot enter the reflected light, the amount of received light P _N decreases, but the reflected light from the detection target SB located farther away from the position where the reflected light can be received. The amount of received light P _N is indicated by an arrow F in the figure, indicating a very high value.

As shown in the graph of Fig. 2, the intensity of reflected light from a close distance is strong. According to the example of Fig. 1, the light receiving point SP _B from the reflected light at the close point _B is much smaller than the originally formed range (indicated by a dotted line), and is formed in other light receiving points SP _A Since the SP _{C is} wider, the amount of light received with sufficient intensity can be obtained.

Next, Fig. 3 is a graph showing the relationship between the position of the center point of the light receiving point of the two-divided light-receiving element 1 and the distance from the sensor to the object to be detected (the mode indicates that the object to be detected SB is from the near side) The result of measuring the position of the light receiving point while moving toward the Far side). As shown in the figure, when the detection target SB is located in the vicinity of the sensor, the position of the detection target SB changes, and the light receiving point also largely moves. However, as the detection target SB moves away from the sensor, the degree of change in the position of the light receiving point gradually becomes slower. In particular, when the detection target SB is moved to the rear of a predetermined distance or more from the reference point, the light receiving point is in a state of being almost immovable.

The opening end edge on the Far side of the opening portion 10 shown in Fig. 1 is set to be in the vicinity of the extreme position in which the range of the light receiving point SP _C is aligned, according to the characteristics shown in Fig. 3 . In addition, since the opening width in the y direction from the edge of the Far side to the vicinity of the position where the light receiving point SP _{C is} formed is set to be slightly wider than the vertical width of the light receiving elements 1N and 1F, the reference point and the reference point are derived. Almost all of the reflected light from the rear passes through the opening 10 and enters the two-divided light-receiving element 1.

On the other hand, the ratio of the Far side element 1F to the outside of the range in which the light receiving point SP _C is formed is shielded by the shielding member 11 .

In addition to the reflected light from the detection target SB, the opening portion 10 is likely to have noise light such as sunlight or illumination light. The noise light system has the possibility of entering the full range of the two-divided light-receiving element 1, but because in the present embodiment, the shielding member 11 shields a considerable amount of impurities. Xunguang, so the noise component overlapping with the received light signal is greatly reduced. In addition, since the light receiving region at the position where the strong reflected light from the close distance is received is narrowed, the range of the Far side element 1F for detecting that the reflected light is not incident is blocked. It does not hinder the detection, but reduces the amount of incident light of the noise light.

Since the noise component superimposed on the received light amount signal in this way becomes small, malfunction such as shown in Fig. 13 (2) can be prevented from occurring. Further, since it is not necessary to reduce the gain of the amplification of the amount of received light, the inclination indicating the change of the differential signal or the addition signal can be made steep, and the responsiveness can be prevented from being lowered.

Further, in the example of Fig. 1, the range formed by the light receiving points SP _A and SP _C from the reference point and the reflected light behind the reference point is such that the opening 10 is formed so as to include the entire width in the opening 10 . The vertical width is widened, but as long as the amount of reflected light required for detection can be ensured, the aspect ratio of the opening portion 10 in the range in which the light receiving points SP _A and SP _C are formed can be received as shown in Fig. 4 (1). The aspect width of the element 1F is narrower. Further, as long as the amount of received light of the intensity required for detection can be ensured, the vertical width of the opening portion 10 in the range in which the light receiving point SP _A is formed by the reflected light from the reference point can be made narrower, and the reference point can be shielded from the reference point. Part of the reflected light.

The opening end edge of the opening portion 10 of the Near side element 1N does not necessarily have to be linearly changed, and may be changed in a curved shape as shown in Fig. 4 (2). Further, in the example of Fig. 1 or Fig. 4 (1) and (2), the opening end edge of the opening portion 10 is gently inclined. However, the opening end edge may be changed in a stepwise manner. In this case, it is also possible to gradually change the step as it approaches the Near side. Also, in each case, an upper and lower opening is formed The end edge is an opening portion 10 having a shape symmetrical with respect to the center line divided into two in the longitudinal direction, but an opening portion in which the upper and lower opening end edges are asymmetric in shape may be provided. Further, the width of the opening portion can be changed by changing only the inclination of the opening end edge of one of the upper and lower sides.

Further, it is also possible to adopt a method of forming a plurality of slit-shaped openings without using one opening, and changing the width of each opening or the number of openings in the y direction from the Far side closer to the Near side. The degree of shading.

Further, it is possible to sufficiently reduce the noise component. However, as shown in Fig. 4 (3), the range of the light-shielding can be set to be the range in which only the reflected light of the Far-side element 1F does not enter. The opening portion 10 corresponding to the entire range of the incident. Conversely, an opening 10 that opens the opening of the near side element 1N and opens in a range facing the entire Far side element 1F may be formed.

Fig. 5 is a view showing an example in which the configuration of Fig. 1 is applied to a jig portion to which a photodetector is mounted.

The jig unit 3 of the present embodiment has a configuration in which a pair of light guiding paths 31 and 32 are formed inside the substantially cylindrical jig body 30 for supporting the optical system, and the rear end portion is mounted and mounted with the light projecting unit 20 or The substrate 36 of the CSP (Chip Size Package) 14 of the light receiving element 1 is divided. Fig. 5 (1) is a front view of the jig portion 3, and Fig. 5 (2) is a perspective view showing a configuration of the back side of the jig portion.

The light projecting window 200 is formed on the rear end surface (the surface on the front side of the CSP 14) of the light guide path 32 on the right side in Fig. 5 (1), and the light receiving window 100 is formed on the rear end surface of the light guide path 31 on the left side. Also, in each light guide The open end faces of the roads 31 and 32 are respectively fitted into the lenses L1 and L2 shown in Fig. 11 .

The light projecting unit 20 is supported in a state of being housed in the accommodating portion 35 provided on the back side of the light guiding path 32. In this state, the light projecting element 2 is in a state of being located at the center of the light projecting window 200.

In the CSP 14 , the two-divided light-receiving element 1 is mounted on the interposer 15 and the front surface of the elements is sealed by the sealing resin 16 , and is supported by the accommodating portion 37 on the back side of the light guiding path 31 . In this supported state, the two-divided light-receiving element 1 is in a state of being opposed to the light-receiving window 100.

In the present embodiment, the rear end surface of the light guiding path 31 of the jig body 30 and the light receiving window 100 function as the shielding member 11 and the opening portion 10 shown in Fig. 1, respectively. That is, the longitudinal width of the light receiving window 100 of the Near side element 1N gradually narrows as it goes away from the boundary with the Far side element 1F. The range of the light receiving window 100 of the Far side element 1F is limited to the range of the range in which the light receiving point SP _{A is} formed, but the vertical width is set to be slightly larger than the vertical width of the Far side element 1F. The length of the range in which the reflected light from the reference point is incident on the near side element 1N is formed to be slightly larger than the near side element 1N.

According to the embodiment of Fig. 5, the area of the light receiving area of each of the light receiving elements 1N and 1F is reduced by the rear end surface of the light guiding path 31 of the jig main body 30 and the light receiving window 100, and the noise component can be reduced. Moreover, since the function of the shielding part 11 is provided in the clamp part 3, the number of parts does not increase, and the increase of the cost is suppressed.

Fig. 6 is a view showing another example of applying the jig unit 3 having the configuration shown in Fig. 1 in a front view and a side view. In addition, by pair and 5th The same components are denoted by the same reference numerals as in FIG. 5, and the description of the details is omitted.

In this example, a shielding plate 4 having an opening 40 is provided between the back surface of the concave portion 31 of the jig body 30 and the CSP 14 including the two-divided light receiving element 1. The light receiving window 100 of the present embodiment is formed to have a size in which the CSP 14 is almost completely exposed, and the shielding plate 4 and the opening portion 40 thereof function as the shielding member 11 and the opening portion 10 shown in Fig. 1 . Therefore, as in the example of Fig. 5, the light receiving regions of the respective light receiving elements 1N and 1F are reduced, and the noise component can be reduced.

According to the configuration of Fig. 6, the number of parts is one more than that of the example of Fig. 5. However, since the added component (shading plate 4) is a simple configuration, the clamp portion 3 having the existing configuration can be used, so the cost is not Become expensive. Further, the photodetector provided with the spacer in order to prevent electromagnetic noise to the substrate 36 may also function as the shield plate 4.

Fig. 7 shows another example in which the configuration of Fig. 1 is applied.

As shown in the fifth and sixth figures, the two-divided light-receiving element 1 is placed in the jig unit 3 in a state in which the CSP 14 is mounted. Fig. 7 (1) shows the state of the CSP 14 viewed from the front. Since the front resin 16 is transparent, the entire divided light-receiving element 1 can be visually recognized.

In the example of Fig. 7 (2), by changing a part of the resin 16 to the resin 16a in which the light-shielding pigment is mixed, the Near side element 1N and the Far side element 1F are respectively shielded from the first side. The member 11 has the same range of shading. In other words, the transparent resin 16 is disposed in a range corresponding to the opening 10 of the first drawing, and the light-shielding resin 16a is disposed at another position, whereby the light receiving region of the Near side member 1N is kept away from The width of the Far side element 1F is gradually narrowed. In addition, the light receiving region of the Far side element 1F is a range from the boundary with the near side element 1N to the vicinity of the limit position where the light receiving point SP _{C is} formed, and the outer side of the range is shielded from light.

In the example of Fig. 7 (2), the light-shielding resin 16a functions to reduce the amount of incident light to each of the light-receiving elements 1N and 1F, similarly to the concave portion 31 of the example of Fig. 5 or the shielding plate 4 shown in Fig. 6 . By means of this, the noise component is cut. In the present configuration example, the step of sealing the resin when the CSP 14 is produced becomes a little complicated. However, since it is not necessary to change the number of parts or the configuration of the jig unit 3, it is possible to prevent an increase in cost.

In the embodiment described so far, each of the light-receiving elements 1N and 1F is partially shielded from light, and each of the light-receiving regions is reduced. However, as shown in FIG. 8, the light-receiving elements 1N and 1F may be changed as shown in FIG. The shape of the method adjusts the light receiving area.

Fig. 8 (1) and (2) show the two-divided light-receiving element 1 in the CSP 14 (the pattern is applied to the internal light-receiving elements 1N and 1F for easy understanding). In either case, the front is sealed by a transparent resin 16.

The two-divided light-receiving element 1 shown in Fig. 8 (1) has a general shape (Near-side element 1N and Far-side element 1F have a rectangular shape of the same size), and in the example of Fig. 8 (2), the Far-side element 1F The horizontal width is reduced to the length of the range in which the reflected light is incident. Further, the Near side element 1N is also formed in a shape that gradually narrows in width as it goes away from the boundary with the Far side element 1F.

By changing the shape of the light receiving elements 1N and 1F themselves in this manner, the light receiving regions of the respective light receiving elements can be reduced. Therefore, the light-receiving area is narrowed under the condition that the reflected light of the required intensity can be detected, It can reduce the amount of incident light of the noise light.

Next, an optical filter that is divided into regions of various transmittances is disposed in front of the two-divided light-receiving element 1 to adjust the amount of light incident on each of the light-receiving elements, and the amount of noise light can be reduced. An example is shown in Figure 9.

In the example of Fig. 9, the optical filter 5 including the size of the entire two-divided light-receiving element 1 is provided in front of the two-divided light-receiving element 1 having a general shape. The optical filter 5 is provided between the back surface of the concave portion 31 of the jig body 30 and the CSP 14 including the two-divided light-receiving element 1 as in the example of the seventh embodiment.

The optical filter 5 is not a mode in which a wavelength is selected, and the light transmittance varies depending on the position in the x direction. Specifically, a range slightly from the outer edge of the Far side to the center portion (corresponding to the boundary between the light-receiving elements 1N and 1F) is set to a completely light-shielding state (transmittance 0%), and includes The range from the center portion to the one side of the near side is set to a completely light transmitting state (transmittance 100%). Further, the outer side (the left side in FIG. 9) having a transmittance of 100% on the near side is divided into a plurality of band regions 50 having different transmittances. The transmittance of each of the belt regions 50 is sequentially reduced in accordance with the distance from the center portion, and the transmission ratio at a distance of 0 is also set in the outermost belt region 50.

In the example of Fig. 9, in the range where the transmittance is set to 100%, the reflected light from the reference point and the reflected light from the point farther than the reference point are incident, but the transmittance is set to 0%. It does not emit light other than noise light. Therefore, the Far side element 1F is reduced in the light receiving area in a range that does not hinder the reception of the reflected light, as in the previous embodiments.

On the other hand, for the Near side element 1N, the light receiving area is not reduced, but by reducing the transmittance of the optical filter 5 in sections, the ratio of the light incident on the Near side element 1N is farther away from the Far side element. The 1F boundary is more and more cut. Therefore, the same effect as that of the light receiving region gradually narrowing in the width direction can be obtained.

Therefore, in the example of Fig. 9, if the transmittance of each band region 50 is adjusted by the range of the amount of received light for which the required intensity is detected by the near-side element 1N, the adjustment and the light-receiving region of the Far-side element 1F are used. The reduction of the amount of incident light of the noise light is drastically reduced, and the detection operation can be stabilized.

Further, as shown in Fig. 10 (1) and (2), in the case where the optical system of the sensor is configured to satisfy the Scheimpflug condition, the diameters of the light receiving points are substantially the same regardless of the position of the object SB to be detected, and As it becomes smaller, it is difficult to adopt a method of shielding the light-receiving surface as shown in Fig. 1 or Fig. 7 and the like. However, the method of the optical filter 5 described above can be introduced regardless of the size of the diameter of the light receiving point. Since the diameter of the light receiving point SP _B generated on the near side is small and the strength is also increased, the amount of received light required for detection can be ensured by the optical filter having a low transmittance.

Since the optical filter 5 described above is not a type that selects the wavelength to be transmitted, it can be produced relatively inexpensively. Therefore, the noise component can be reduced to the same extent as other embodiments without increasing the cost.

Further, in the example of Fig. 9, the optical filter 5 is disposed in front of the two-divided light-receiving element 1 in the same manner as the shielding plate 4 of the example of Fig. 6, but the optical filter is also not limited thereto. Lighter 5 sticks to the The surface of the resin 16 sealed by the light-receiving element 1 is divided.

Each of the above-described embodiments is not limited to a two-divided light-receiving element, and is applied to a light-receiving element used in a reflective photosensor measured according to the principle of triangulation by a one-dimensional or two-dimensional CMOS, CCD, or the like. The amount of incident light of the noise light can be greatly reduced, and the detection operation becomes stable.

10‧‧‧ openings

11‧‧‧Shielding members

SP _A , SP _B , SP _C ‧‧‧ light spot

Light-receiving element on the 1N‧‧‧Near side

1F‧‧‧Far side light-receiving element

Claims (16)

A reflective photosensor is a light-emitting element that projects light and a light-receiving element that receives light from an object that receives light from a light-emitting element by receiving light in one direction, in the longitudinal direction of the light-receiving surface. A reflective photosensor provided in accordance with a relationship in which an imaging position of the reflected light changes in accordance with a distance at which the reflected object is generated is characterized in that the light receiving element is in proximity to an object that reflects light from the light projecting element. In the case of the detector, light is received in a light receiving region whose width gradually decreases in a direction in which the image forming position of the reflected light is moved. A reflective photosensor according to claim 1, wherein in the front of the light receiving element, the case where the object reflected by the light from the light projecting element is brought close to the sensor has an image along the reflected light The shielding member of the opening portion having a shape in which the width in the direction in which the position moves is gradually narrowed, and the shielding member shields a part of the reflected light that can enter the light receiving surface. The reflective photosensor of claim 2, wherein the shielding member is integrally opposed to the light receiving surface of the light receiving element, and the opening portion receives the reflected light from a position relatively far from the sensor. The area on the Far side is set to be outside the range outside the limit position imaged by the reflected light. The reflective photosensor according to claim 2, wherein a surface of the jig portion mounted in the light receiving element before the light receiving element functions as the shielding member, and the reflected light passes through and is guided to the light receiving element. The light receiving window formed on the surface functions as the opening. A reflective photosensor according to claim 2 or 3, wherein the The shielding member is disposed between the surface of the light receiving element and the light receiving element, and the surface of the light receiving element is placed on the surface of the light receiving element so that the reflected light passes through and is guided to the light receiving element. A light receiving window having a large opening portion of the shielding member. The reflective photosensor according to claim 1, wherein the light-receiving surface of the light-receiving element is divided into a region covered with a light-shielding resin and an uncoated region, and is not covered with the resin. The area is set to a shape in which the object that reflects the light from the light projecting element approaches the sensor gradually narrows in width in the direction in which the image forming position of the reflected light moves. The reflective photosensor of claim 6, wherein the region of the Far side of the reflected light from the position of the sensor relatively far from the light receiving surface of the light receiving element is imaged by the reflected light The outer side of the extreme position is covered with a light-shielding resin. The reflective photosensor of claim 1, wherein the light receiving surface of the light receiving element has an image forming position of the reflected light when the object reflecting the light from the light projecting element is brought close to the sensor. The shape in which the direction of the movement is gradually narrowed. The reflective photosensor of claim 8, wherein the length of the light receiving surface is set to receive an edge of a region on the Far side of the reflected light from a position of the sensor relatively far from the light receiving surface. The vicinity becomes the extreme position where the reflected light is imaged. A reflective photosensor is a light-emitting element that projects light and a two-divided light-receiving element that receives light from an object that receives light from a light-emitting element, and the reflected light is formed in an array direction of each light-receiving element. A reflection type photosensor in which a position is changed in accordance with a relationship in which the position of the object to be reflected changes, and a detection signal is output based on a difference value of the amount of received light between the respective light receiving elements, characterized in that the two divisions are In the light receiving element, the light receiving element on the near side that receives the reflected light from the position relatively close to the sensor is at the boundary of the light receiving element on the Far side that is away from and receives the reflected light from the position relatively far from the sensor. The light-receiving area whose width is gradually narrower accepts light. The reflective photosensor according to claim 10, wherein the front side of the light receiving element on the near side is provided with an opening having a shape that gradually narrows in width as it goes away from the boundary of the light receiving element on the Far side. The shielding member shields a part of the reflected light that can enter the light receiving element on the near side by the shielding member. The reflective photosensor of claim 11, wherein the shielding member is opposed to the front surface of the two-divided light-receiving element, and the opening portion extends across the boundary between the light-receiving elements and is extended to the light side of the Far side. The partial range of the element is formed on the Far side light-receiving element by the reflected light from the far side of the reflected light of the light-receiving element formed on the near side via the opening portion of the light-receiving element on the Far side. The reflective photosensor according to claim 11 or 12, wherein a surface of the clamp portion in which the two-divided light-receiving element is placed before the two-divided light-receiving element functions as the shielding member, in order to pass the reflected light The light receiving window formed on the surface by the two-divided light receiving element acts as the opening. Such as the reflective type photo sensor of claim 11 or 12, wherein The shielding member is disposed between the surface located before the two-divided light-receiving element and the two-divided light-receiving element in the jig portion that is incorporated in the two-divided light-receiving element, and is located on the surface before the two-divided light-receiving element, in order to make the reflection The light passes through and is guided to the light receiving element to form a light receiving window larger than the opening of the shielding member. A reflective photosensor is a light-emitting element that projects light and a light-receiving element that receives light from an object that receives light from a light-emitting element by receiving light in one direction, in the longitudinal direction of the light-receiving surface. A reflective photosensor equipped with a relationship in which an imaging position of the reflected light changes in accordance with a distance at which the reflected object is generated, wherein the light receiving surface of the light receiving element is received from a relatively close proximity to the sensor. The front side of the region on the near side of the reflected light at the position is provided with an optical filter designed to have a gradually decreasing transmittance as it goes away from the area on the Far side that receives the reflected light from the position relatively far from the sensor. The reflective photosensor of claim 15, wherein the optical filter is opposed to the light-receiving surface of the light-receiving element as a whole, and the contrast light is reflected in a portion opposite to the area on the Far side. The range outside the extreme position of the image is set to a non-transmissive state.