JPH07280513A - Optical device - Google Patents

Abstract

PURPOSE:To eliminate error measurement by the influence of an edge and contrive the lengthened distance of a distance measurement range by making two or more of light flux casted on an object from a light casting part in an optical device for distance measurement. CONSTITUTION:At least two pieces of light flux different in optical axes are casted on an object by emission elements 1a, 1b and two pieces of reflection light of the light flux reflected from the object are received by a light receiving element 2 divided into at least two areas. The spot of the reflection light is formed at a separated position on the light receiving element 2, and a distance of the light receiving signal to the object can be measured. In addition, judgement can be performed on whether the object is within a specified distance range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention emits light to an object,
The present invention relates to an optical device that measures the distance to an object by receiving the reflected light.

[0002]

2. Description of the Related Art As a conventional optical device for distance measurement, there is a photoelectric sensor using a triangular distance measurement method having a structure as shown in FIG. The optical system of this apparatus comprises a light emitting element 1 and a light projecting lens 3 for projecting light, a light receiving element 2 and a light receiving lens 4 for receiving light, and the light receiving element 2 can detect the position of a spot in a one-dimensional direction. , For example, a two-part photodiode or P
SD or the like is used. Device to object (M1, M2, M3)
When the distance to is changed, the spot of the reflected light from the object on the light receiving surface of the light receiving element 2 becomes, as shown in FIG.
Move to a position corresponding to the distance of the object in a fixed direction. The position of the spot is detected by the light receiving element 2, and the distance from the position to the object is measured.

[0003]

However, such a conventional optical device has the following problems. First, as shown in FIG. 3, when the object is located at the position M2 and only a part of the projected projection beam is reflected by the object, the spot is generated due to the edge of the object. Light is received as shown in FIG. 4A, and in this case, output 1
The ratio of (output corresponding to area 1) and output 2 (output corresponding to area 2) is as shown in FIG.
The ratio of the output 1 and the output 2 at the position is the same. That is, as shown in FIGS. 4C and 4D, when the shaded portion X of the spot is missing due to the influence of the edge, (A1
When -X) / B1 = A1 '/ B1', the object at the position of M2 is erroneously measured as the position of M1. That is, although the object is at the position of M2, it is determined to be at the position of M1 and the distance measurement is erroneous. Note that the dividing lines in the figure are the regions 1 and 2 of the light receiving element 2.
Indicates the boundary of. Secondly, in order to increase the distance of the distance measuring range, the point A where the central optical axes of the light projection and the light reception intersect in FIG. 1 is set far and the angle θ is reduced. Distance measurement becomes difficult in a close range, and it is possible to shorten the distance between the light emitting element and the light receiving element, but this is limited due to the size of the lens and the like. For these reasons, there is a limit to increasing the distance.

The present invention solves the above-mentioned problem. In an optical device for distance measurement, by using two or more luminous fluxes to illuminate an object from a light projecting portion, erroneous measurement due to the influence of edges is eliminated. It is an object of the present invention to provide an optical device capable of achieving a long distance measurement range.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 is such that a light projecting portion for emitting at least two luminous fluxes having different optical axes toward an object and the object is reflected by the object. And a light receiving element divided into at least two regions for receiving the reflected light of the two light fluxes through a condensing element or an aperture, and the light receiving element has the reflected light at different positions on the light receiving element. And a distance measuring means for measuring a distance to an object based on a light receiving signal from the light receiving element. According to a second aspect of the present invention, a light projecting unit that emits at least two light beams having different optical axes toward an object and a reflected light of the two light beams reflected by the object is passed through a condensing element or an opening. A light-receiving element divided into at least two regions, each light-receiving element being arranged so that the reflected light forms a spot at a different position on the light-receiving element; An object detection means for determining whether or not the object exists within a predetermined distance range based on the light reception signal from the light receiving element. According to a third aspect of the present invention, in the optical device according to the first or second aspect, the two spots formed on the light receiving element are present one by one in two divided areas of the light receiving element. It is a thing. According to a fourth aspect of the invention, in the optical device according to the third aspect, the two spots formed on the light receiving element have the same distance from the dividing line of the light receiving element to the center of each spot. The invention of claim 5 is
In the optical device according to a third aspect of the present invention, the two spots formed on the light receiving element have a movement direction of the spot substantially parallel to the dividing line of the light receiving element when the object moves. According to a sixth aspect of the present invention, in the optical device according to any one of the first to fifth aspects, the light projecting section alternately emits the light beam, and the light receiving section outputs the light receiving signal in synchronization with the emission timing of the light beam. It is something to process. The invention of claim 7 is
In the optical device according to any one of claims 1 to 6 (the same applies hereinafter), the light projecting unit emits two light beams having different optical axis directions. According to the invention of claim 8, the light projecting section emits two light beams whose optical axes are displaced in parallel. According to the invention of claim 9, the light projecting portion includes two light emitting elements. According to a tenth aspect of the present invention, the light projecting section includes one light emitting element and a light beam separating means for separating a light beam emitted from the light emitting element into two light beams. According to the invention of claim 11, the light projecting portion emits two light beams having different wavelengths. According to the twelfth aspect of the invention, the light projecting section emits two light beams having different polarizations. According to the thirteenth aspect of the invention, the light projecting portion emits two light beams having different divergence angles. According to a fourteenth aspect of the present invention, the light receiving portion includes a color sensor divided into at least two regions. According to the invention of claim 15, the light receiving portion is provided with a divided light receiving element divided into at least four regions by three parallel dividing lines. Claim 1
According to a sixth aspect of the present invention, the light receiving portion includes a divided light receiving element divided into at least three regions by two parallel dividing lines. According to a seventeenth aspect of the present invention, the light receiving portion includes a divided light receiving element divided into at least four regions by two dividing lines intersecting each other. The invention according to claim 18 is provided with a detecting means for detecting whether or not the emitted light beam is correctly reflected by the target object from the received light amount of the reflected light from the target object for each of the two light fluxes. Is. The invention according to claim 19 is provided with a detecting means for obtaining distance information for each of the two light fluxes and for detecting whether or not the distance information obtained for each light flux matches. According to a twentieth aspect of the present invention, in the optical device according to the nineteenth aspect, the distance to the object is measured only when the distance information obtained for each light beam is the same.

[0006]

According to the optical device of the present invention, at least two luminous fluxes having different optical axes are emitted toward the object by the light projecting section, and the reflected light of the two luminous fluxes reflected by the object is condensed by the condensing element or Through the opening, light is received by a light receiving section composed of a light receiving element divided into at least two regions. The spots of the reflected light are formed at different positions on the light receiving element, and the distance to the object can be measured by the distance measuring means from the light receiving signal of the light receiving element. Since two light fluxes are used,
The influence of the edge of the object is reduced. Further, the object detecting means can determine whether or not the object exists within a predetermined distance range.

[0007]

【Example】

(Embodiment 1) A configuration of an optical device (distance measuring sensor) according to Embodiment 1 is shown in FIG. 5, (a) is a side view of a light projecting portion, and (b) is an overall top view. FIG. 6 shows a state of a spot in which the reflected light from the object M1 is received by the two-division light receiving element,
(A) shows a spot by the light emitting element 1a, (b) shows a spot by the light emitting element 1b, and (c) shows a distance measuring range. The device includes light receiving elements 1a and 1b that form a light projecting unit that emits two light beams having different optical axes toward an object, and two regions that receive the reflected light of the two light beams reflected by the object. The light receiving element 2 has a divided light receiving portion, and the light receiving element 2 forms spots at different positions on the light receiving element 2 and the moving direction of the spot when the object moves. Are arranged so as to be parallel to the dividing line of the light receiving element 2. In detail, the center of the spot in FIG. 6 moves parallel to the dividing line while the spot diameter increases as the object moves away. 2 at the light receiving part due to the change of the spot diameter
Distance measurement is performed from the change in the ratio of the amount of received light in one area.

Now, comparing FIG. 2 and FIG. 6 (c),
The range-finding range in FIG. 2 is the range where the spot intersects the dividing line. On the other hand, in the present embodiment of FIG. 6, the center of the spot moves parallel to the dividing line, so the dividing line and the spot always intersect, and the distance measuring range is the width of the light receiving element. As described above, according to this embodiment, the range can be expanded. FIG. 7A and FIG. 7B show the distance measuring ranges of the conventional example and the present example in comparison. FIG. 8 shows an example of a light receiving signal processing circuit in this embodiment. In the processing circuit of FIG.
The light emitting elements 1a and 1b alternately emit light, and the reflected light of the emitted light by the object is received by the two-divided light receiving element 2. By processing the received light signal in synchronization with the light emission timing, the outputs A1 to B2 in FIG. 6 can be separated. Replace A1 and B2 with {(A1 + A2)-(B1 + B
2)} / {(A1 + A2) + (B1 + B2)} and the distance is measured from the output value.

(Embodiment 2) The present embodiment 2 is different from the embodiment 1 only in the processing circuit, and has the same optical system configuration as shown in FIG. The processing circuit is shown in FIG. In the optical system shown in FIG. 5, two light beams are alternately emitted from the light projecting portion including the two light emitting elements 1a and 1b and the light projecting lens 3. The light receiving section receives the reflected light reflected by the object by the light receiving element 2 via the light receiving lens 4. It is assumed that the light receiving element 2 can detect the position change of the spot on the light receiving surface of the two-divided photodiode, PSD or the like. Since the two light beams are emitted alternately, the two states of FIGS. 6A and 6B are repeated on the light receiving surface. Further, the light receiving unit is configured such that the positions of the spots (a) and (b) are symmetrical with respect to the dividing line.
FIG. 9 shows the light emitting elements 1a and 1b and the outputs 1 and 2 of FIG. 6, and the states of (a) and (b) are repeated. When the output of FIG. 9 is processed by the processing circuit of FIG. 10 in synchronization with the emission timing, the received light signals A1 and B2 of each spot can be separated. So A
It is determined whether or not the formula of 1: B1 = A2: B2 is satisfied, and if satisfied, the processing circuit of FIG.
If not satisfied, distance measurement is not performed.

The effects of the second embodiment are as follows. Figure 5
As shown in (a), when the object is at the position of M2 and the influence of the edge is present, the states of FIGS. 11 (a) and 11 (b) are repeated on the light receiving surface. In this case, FIG. 6 (a) and FIG.
Comparing (a) clearly shows that in the case of FIG.
Output value becomes smaller. Then A1: B1 = A2: B
2 will not hold. This is common to all cases where there is an influence of an edge, and erroneous measurement due to the influence of an edge can be eliminated by measuring the distance only when A1 = B1 and A2 = B2 are satisfied. Moreover, since the configuration of the first embodiment is also satisfied,
The effect of expanding the range is also obtained.

(Embodiment 3) FIG. 12A is a side view of the entire apparatus according to Embodiment 3. The two light fluxes alternately emitted from the light projecting portion travel toward the object M in parallel with the distance measuring direction. The light receiving element 2 is arranged at the midpoint between the two light emitting elements 1a and 1b. The light reflected by the object M is received by the light receiving element 2 as shown in FIGS. The two spots are located symmetrically with respect to the dividing line of the two-divided light receiving element. Since this is the same state as in the first and second embodiments, the same effect as in the first and second embodiments can be obtained.

(Embodiment 4) FIG. 13A is a side view of a light projecting portion according to Embodiment 4, and FIG. 13B is an overall top view. In the fourth embodiment, a two-wavelength light emitting diode (LED) is used as the light emitting element 1, and the wavelength λ emitted from this is used.
The dichroic mirror (DCM) 5 splits the light fluxes of 1 and λ2 and uses the mirror 6 to direct them to the object M as two light fluxes. The light reflected by the object M is spectrally separated for each wavelength using the dichroic mirror 7, and is received by separate light receiving elements 2a, 2b via the light receiving lenses 4a, 4b. FIG. 14 shows the positions of spots on the light receiving elements 2a and 2b. The light receiving elements 2a and 2b are arranged so that the spots are symmetrical with respect to the dividing line, and A1: B1 and A2: B are arranged.
Compare the two ratios. Then, depending on whether or not the ratio is the same, it is determined whether or not distance measurement should be performed (similar to the second embodiment).
Perform distance measurement. The processing circuit shown in FIG. 15 is used. The effect of the present embodiment is the same as that of the second embodiment in that erroneous measurement due to the influence of the edge is eliminated, and the expansion of the distance measuring range is performed in the first embodiment.
Is the same as.

(Embodiment 5) FIG. 16A is a top view of a light receiving portion according to the embodiment 5, and FIG. 16B is a side view of the light emitting portion.
This embodiment is the same as the dichroic mirrors 5 and 7 of the fourth embodiment.
Are arranged in the divergent light path of the light projecting section and in the converging light path of the light receiving section respectively, and the processing of the light reception signal is the same as that described above. According to this embodiment, the device can be downsized as compared with the fourth embodiment, and the same effect as that of the fourth embodiment can be obtained.

(Sixth Embodiment) FIG. 17A shows the structure of a light projecting portion according to the sixth embodiment. The light projecting section has two light emitting elements 1a,
1b and a polarization beam splitter 8 are provided, and the light emitting element 1a,
Alternately emit 1b. The light receiving unit may be the same as that shown in FIG. With this configuration, the light projecting unit emits two light beams having different polarization directions (see FIGS. 17B and 17C) toward the object. Since the light emitting elements 1a and 1b emit light alternately, the light flux 1 and the light flux 2 are emitted alternately. The light reflected by the two light beams is received by the light receiving section. The light receiving section is configured such that the two spots on the light receiving surface are symmetrical with respect to the dividing line, and its output is processed in the same manner as in the second embodiment (the values of the ratios are compared, and if they are the same, measurement is performed). Distance, if not, do not measure). According to the sixth embodiment, the distance measurement is performed by determining only when there is no influence of the edge, so that there is no erroneous measurement. Further, by emitting two light beams with different polarization directions from the light emitting element 1, it is possible to eliminate the loss due to the reflection and transmission at the polarization beam splitter 8. Further, the same effect as that of the first embodiment is obtained.

(Seventh Embodiment) FIG. 18 is a side view of a light projecting portion according to a seventh embodiment. The light projecting unit includes two light emitting elements 1a and 1b that alternately emit light and a half mirror 9. The half mirror 9 transmits one light beam 1 and reflects the other light beam 2 to emit the light toward an object. A two-divided light receiving element similar to that shown in FIG. 5 is used for the light receiving portion that receives the reflected light from the object. The light receiving unit is configured such that the two spots are symmetrical with respect to the dividing line. By processing the output from the light receiving unit in the same manner as in the second embodiment, the same effect as in the first and second embodiments can be obtained.

(Embodiment 8) FIGS. 19A and 19B are a side view and an overall top view of a light projecting portion according to an embodiment 8. The same light emitting unit as that used in Examples 4 and 5 was used for the light emitting unit, and one color sensor 12 was used for the light receiving unit instead of the two light receiving elements. The light beams projected from the light emitting elements 1a and 1b are transmitted and reflected by the dichroic mirror 5, and are projected onto the object M as two light beams having different wavelengths. The light receiving lens 4 receives the light reflected by the object M.
The light is received by the color sensor 12 via.

FIG. 20 shows a state where the color sensor 12 receives light. In the figure, output 1 is the amount of received light of wavelength 1 in region 1, output 2 is the amount of received light of wavelength 1 in region 2, output 1'is the amount of received light of wavelength 2 in region 1, The output 2 ′ is the amount of received light of wavelength 2 in region 2. Here, if the spots formed by the two light fluxes are made to be symmetrical with respect to the dividing line of the color sensor 12, the same state as that of the first embodiment is obtained, so that the distance measuring range can be expanded. Further, outputs 1 to 2'correspond to A1 to B2 of the second embodiment, and output 1 / output 2
By comparing output 2 '/ output 1'and measuring the distance only when the values are the same, erroneous measurement due to the influence of edges can be eliminated. Further, when there is no influence of the edge, the same effect as that of the first embodiment can be obtained. Further, the size can be reduced by changing the two light receiving elements to the color sensor 12. The processing circuit of this embodiment is shown in FIG.

FIG. 22A is a side view of the light projecting portion according to the ninth embodiment, and FIGS. 22B and 22C are views showing spots on the light receiving element by the objects M1M2. The light projecting section causes the two light emitting elements 1a and 1b to alternately emit light, and projects the two light beams having different divergence angles. The light flux with a small divergence angle is always arranged within the range of the light flux with a large divergence angle. The same light receiving unit as that shown in FIG. 5 is used, and the reflected light reflected by the object is received by one two-divided light receiving element via the light receiving lens. When the distance from the distance measuring sensor to the object changes, the spot of the reflected light moves on the light receiving surface, but the dividing line of the two-divided light receiving element is made parallel to the moving direction. Then, as shown in FIG. 22B, the spot formed by the light flux having a large divergence angle is divided in half by the dividing line,
The spot with a small divergence angle is configured so that its center is not on the dividing line.

The output from the light receiving element is processed by the processing circuit of FIG. 23, and the distance is measured by the output. Here, only the light flux with a small divergence angle is used for distance measurement, and the spot due to this light flux has a spot diameter when the distance from the object to the distance measurement sensor changes, as shown in the diagram on the left side of FIG. Since it changes, the ratio of A1 and B1 changes and distance measurement can be performed. This is the same as in the first embodiment. Also, take the ratio of B2 and A2 and confirm that this is 1: 1. When B2: A2 = 1: 1 is not satisfied, an error signal is output. According to the ninth embodiment,
When there is an edge effect like the object M2, the light is received on the light receiving surface as shown in FIG. 22 (c), the ratio of B2 and A2 is not 1: 1, and the output of A1 and B1 is affected by the edge. When exiting, the ratio of B2 and A2 is not always 1: 1. Therefore, when B2: A2 = 1: 1, distance measurement is performed and B2: A2 ≠
In the case of 1: 1, an error signal is output to eliminate erroneous measurement due to the influence of edges, and only correct distance measurement can be performed. Further, since the light receiving element is in the same state as that of the first embodiment, the same effect can be obtained.

(Embodiment 10) This embodiment 10 is shown in FIGS. In the tenth embodiment, the configuration of the optical system,
The light projecting / light receiving method and the like are the same as those in the first embodiment shown in FIG. 5, only the processing circuit is different, and the distance measuring range is expanded. The processing circuit shown in FIG. 27 is used. Example 1
At 0, the device is used as a distance setting type photoelectric switch that determines whether or not the object is within a predetermined distance range. In many cases, the device for this purpose is used in such a manner that when a conveyed work passes in front of the device, it is detected and the switch is turned on. Therefore, due to the work's own edge,
Even if the work is detected closer than it actually is, there is no problem because the output is definitely ON. On the other hand, even if the work is detected farther than it actually is, the work always passes in front of the device, so that the work always comes to a position where there is no influence of the edge. At that time, the switch is turned on, so there is no problem. The problem is the work
This is a case in which the background is erroneously detected due to the influence of the edge such as the background and the switch is turned on although the background is in the OFF state due to the absence of the background. This means that in the distance setting type photoelectric switch, detecting the object before the original position becomes a problem.

In the prior art and the present embodiment, consider a case where an object is detected in advance due to the influence of edges. Conventionally, according to the positional relationship between the light emitting / receiving unit in FIG. 3, the spot moves to the left as shown in FIG. 4B to FIG. 4A when the object becomes far.
Therefore, if the area of A1 in (c) becomes large, it will be detected far. Therefore, as shown in FIG. 4C, when the area of the region 1 is lacking due to the influence of the edge, the original M
It is detected closer than the position 2. In the present embodiment, the values of (A1 + A2) and (B1 + B) are obtained from the four outputs (see FIGS. 5 and 6) obtained from the two light emitting elements which emit light alternately.
Calculate the value of 2) and measure the distance from that value. FIG. 28 shows changes in the amount of received light depending on the position of the object. In FIG. 28, it can be seen that (A1 + A2) decreases and (B1 + B2) increases when the object M is closer. That is, (A1 + A2) becomes smaller due to the influence of the edge, and (A1 + A2) becomes smaller.
If the value of + A2) / (B1 + B2) becomes smaller, the object M is detected closer to the original position.

FIG. 25 and FIG. 26 are diagrams showing the state of spots by the light emitting elements 1b and 1a when the edge of the object is at various positions. Here, consider a case where the position is detected closer than the state where the original position can be detected (the edge is below the point S in FIG. 24). The shaded area in the figure is the area where there is no reflected light. (1) Edge is above point P: (A) of FIG. 25 and (a) of FIG. 26, (A1 + A2) / (B1 + B2)
= ∞ and it is detected in the distance. (2) Edge is between P and Q: In the states of (a) of FIG. 25 and (b) of FIG. 26, the outputs of B1 and A2 are 0. A
Although 1 and B2 have outputs, B2 has a larger area reduction rate due to the influence of the edge as compared with the case where there is no influence of the edge (because the center of the spot is not on the dividing line). Therefore, (A1 + A2) / (B1 + B2) becomes large and is detected at a distance. (3) The edge is between Q and S: the states of (b) of FIG. 25, (c) of FIG. 25, (c) of FIG. 25 and (c) of FIG. 26. In the former case, the reverse of the above. A2 is greatly affected by the edge, and (A1 + A2) / (B1 + B2)
Will be smaller and will be detected nearby. In the latter case, only A2 is affected by the edge, and (A1 + A2) /
(B1 + B2) becomes smaller and is detected in the vicinity. (4) Edge is below S: Distance is correctly measured. As described above, the problem is when the edge is between Q and S, and the performance only in this case will be described below in comparison with the related art.

When the detection is made closer to the original position due to the influence of the edges, the comparison of the conventional example with the present example shows that the received light signal processing is the same in the conventional example (see FIGS. 3 and 4) and the present example. Yes, (α−β) / (α + β) α, β: received light signal of each region of the two-divided light receiving element. The conventional method is the symbol in FIG. 4, α = A1, β = B1, and the present embodiment is the symbol in FIG. 29, α = A1 + A2, β =
B1 + B2. When the influence of the edge appears (when the portion X in FIG. 4 and FIG. 29 is not received), the value of α or β changes as compared with the case where there is no influence of the edge, and therefore (α−β) / (α
+ Β) output changes. Therefore, erroneous measurement is performed. That is, the error depends on the degree of change in the value of α or β. In the conventional method (see FIG. 4), the change in the value of α is A1 → A1
-X, change rate is (A1-X) / A1 = 1- (X / A1)
In contrast, in the present embodiment (see FIG. 29), the change in the value of α is (A1 + A2-X) / (A1 + A2) = 1- {X / (A
1 + A2)} Since A1 = A2 in this embodiment, 1- {X / (A1 + A2)} = 1- {X / 2 · A1}. Therefore, according to the present embodiment, the effect that the error detected closer (previously) than the actual one becomes smaller than the conventional one.

(Embodiment 11) FIG. 30 is a side view of a light projecting portion according to embodiment 11, and FIG. 31 is an overall top view including a light receiving portion. The light projecting unit includes two light emitting elements 1a and 1b and an optical element 13. The light emitting element 1b has two different wavelengths 1 and 2.
Of light, the surface of the optical element 13 reflects the wavelength 1 and
The optical multilayer film that transmits the wavelength 2 is provided, and the back surface is provided with the optical multilayer film that reflects the wavelength 2. That is, the light emitted from the light emitting element 1b by the optical element 13 has a different optical axis.
It is emitted as a light flux of a book. The luminous flux emitted from the light emitting element 1a has a wavelength 3 different from the wavelengths of the two luminous fluxes, passes through the optical element 13, and is emitted. Further, the light emitting elements 1a and 1b alternately emit light. As shown in FIG. 31, the light receiving section disperses the reflected light of three wavelengths, and the light receiving element 2
Light is received by a, 2b, and 2c.

FIG. 32 shows a state of a spot irradiated on an object. The light flux with wavelengths 1 and 2 is within the range of the light flux with wavelength 3. FIG. 33 shows the appearance of spots on each light receiving element. The spots of wavelength 1 and wavelength 2 are configured to be symmetrical with respect to the dividing line of the two-divided light receiving element. Therefore, the conditions of Example 1 are satisfied. FIG. 34 shows a processing circuit. When the spot on the light receiving element in FIG. 33 has an influence from the top or bottom, if A3 = B3, there is no influence, and processing is performed with α = A1 + A2 and β = B1 + B2. If A3> B3, there is an edge effect in the area on the B3 side, so processing is performed with α = A1 and β = B2. A3 <B
If it is 3, for the same reason, processing is performed with α = A2 and β = B1. When A3 or B3 = 0, an error signal is emitted.
In this embodiment, since A1 = A2 and B1 = B2, correct distance measurement can be performed by the above method except when A3 or B3 = 0. Also, in the case of A3 or B3 = 0, an erroneous measurement can be prevented by outputting an error signal. Further, the distance measuring range is expanded because it satisfies the configuration of the first embodiment.

(Embodiment 12) In Embodiment 12, the light receiving element of Embodiment 2 is replaced with a four-divided light receiving element. The configuration of the light emitting / receiving unit is similar to that of the first embodiment shown in FIG. 5, and the same effect as that of the first embodiment can be obtained. FIG. 35 shows the state of the spot. There are eight outputs A to D and A'to D'from the light receiving element. In the second embodiment (see FIG. 5), A1, B1, A
The distance was measured from the four outputs B2 and B2. The distance measuring method is A + C = α, A ′ + C ′ = α in this embodiment.
It is the same as processing each corresponding to A1, A2, B1 and B2 by setting ', B + D = β, B ′ + D ′ = β ′. The processing for the influence of the edge is the same as that of the second embodiment, and the same effect can be obtained by making the outputs correspond to each other and performing the processing of the second embodiment as described above.

In this embodiment, first, A + B,
When the value of C + D is calculated and either value is 0 (when the spot does not intersect the dividing line 1), α = A + C,
As α ′ = A ′ + C ′, β = B + D, β ′ = B ′ + D ′, {(α + α ′) − (β + β ′)} / {(α + α ′) +
(Β + β ′)}. And A + B ≠ 0 and C + D ≠ 0
In the case of, α, α ′, β, β ′ are respectively A + B,
By switching to A '+ B', C + D, C '+ D', processing is performed by the above equation. The processing circuit shown in FIG. 37 is used.

The movement of the spot when there is no influence of the edge and the object moves away from the sensor is as shown in FIG. 35 (the optical system is FIG. 5). The spots of the light emitting elements 1a and 1b are located symmetrically with respect to the dividing line 2, and when the object moves away, the radius of the spot increases and the center moves parallel to the dividing line 2. Considering the change in the amount of received light in each area when the spot moves, consider the case where the right side of the spot is in contact with the dividing line 1 and the left side is in contact with it, as shown in FIG. The spot formed by the element 1b is symmetrical with respect to the dividing line 2 and is not shown in the drawing).

Here, assuming that the distance measurement is performed with a value of (α-β) / (α + β) (actually, there is also a spot output by the light emitting element 1b, {(α + α ')-(β + β')} /
The expression {(α + α ′) + (β + β ′)} is used. In this case, since α = α ′ and β = β ′, α ′ and β ′ do not have to be taken into consideration), and α = A + B and β = C + D, (α-
The value of β) / (α + β) is β = 0 in the state of (c), so α / α = 1, and in the state of (d) is α = 0, and thus −β / β = −1. . On the other hand, α = A + C, β = B
Considering the case where the amount of change in the value of (α−β) / (α + β) is the largest as + D, the center of the spot is the dividing line 2
Since it moves parallel to, when the radius is infinite, (α-β) /
The minimum is (α + β) = 0, and the maximum is (α−β) / (α + β) = α / when the dividing line 2 is in contact as shown in (c).
α = 1. The former is a change from -1 to 1, while the latter is a change from 0 to 1. Therefore, while the spot intersects the dividing line 1, α = (A + B), β =
By switching to (C + D) and performing the distance measurement with that value, the sensitivity to the displacement of the spot is increased and the distance measurement sensitivity is increased.

Considering the case where there is an influence of an edge, since the conventional method and each method of the first to eleventh embodiments use a two-divided light receiving element, as shown in FIG. 4C, FIG. 25 and FIG. In addition, a large measurement error occurred when the influence of the edge appeared parallel to the dividing line. However, in this embodiment, the spot is shown in FIG.
Since the distance is measured by the dividing line 1 while the dividing line 1 of 6 is intersected, there is also an effect that the influence of the edge having a large error in the related art is reduced. In the present invention, it is sufficient that at least two light beams have different optical axes, and the directions may be different or may be parallel. Also, three or more light beams may be used.

[0031]

As described above, according to the optical device of the present invention, at least two light beams having different optical axes are projected toward the object, and the reflected light reflected by the object is received by the light receiving element. By doing so, a spot is formed at another position on the light receiving surface, and the distance to the object is measured by this received light amount, so compared to the conventional one that projects one light beam to form one spot. Thus, the measurement error due to the influence of the edge of the object can be reduced, and an error can be output when there is the influence of the edge, and erroneous measurement can be eliminated. It is also possible to determine whether the object is within a predetermined distance range based on the amount of received light. Furthermore, by setting the moving direction of the spot when the object moves to be parallel to the dividing line of the light receiving element, the distance measuring range can be expanded as compared with the related art.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical system of a conventional triangulation method.

FIG. 2 is a diagram showing a movement of a spot in the triangulation method.

FIG. 3 is a diagram of an optical system showing an influence of an edge of an object.

FIG. 4 is a diagram for explaining an influence of an edge of an object.

FIG. 5 is a diagram showing a configuration of an optical system of an optical device according to Example 1 of the present invention.

FIG. 6 is a diagram showing the movement of spots in the first embodiment.

FIG. 7 is a diagram showing a comparison between a conventional example and an example.

FIG. 8 is a block diagram of a processing circuit according to the first embodiment.

FIG. 9 is a diagram showing how light is received and output.

FIG. 10 is a block diagram of a processing circuit according to second, third, sixth, seventh and ninth embodiments.

FIG. 11 is a diagram showing a state of a spot on a light receiving element.

FIG. 12 is a diagram showing a configuration of an optical system of Example 3 and a state of spots on a light receiving element.

FIG. 13 is a diagram showing a configuration of an optical system of Example 4.

FIG. 14 is a diagram showing how light is received in the fourth embodiment.

FIG. 15 is a block diagram of a processing circuit according to the fourth and fifth embodiments.

FIG. 16 is a diagram showing a configuration of an optical system of Example 5.

FIG. 17 is a diagram showing a configuration of an optical system and a luminous flux of Example 6.

FIG. 18 is a diagram showing a configuration of an optical system of Example 7.

FIG. 19 is a diagram showing a configuration of an optical system of Example 8.

20 is a diagram showing a color sensor used in Example 8. FIG.

FIG. 21 is a block diagram of a processing circuit according to an eighth embodiment.

FIG. 22 is a diagram showing a configuration of an optical system of Example 9 and a state of spots on a light receiving element.

FIG. 23 is a block diagram of a processing circuit according to a ninth embodiment.

FIG. 24 is a diagram showing the structure of the optical system of Example 10;

FIG. 25 is a diagram showing the appearance of spots in Example 10. FIG. 26 is a diagram showing the appearance of spots in Example 10;

FIG. 27 is a block diagram of a processing circuit according to the tenth embodiment.

28 is a diagram showing changes in the amount of received light in Example 10. FIG.

FIG. 29 is a diagram showing the appearance of spots in Example 10.

FIG. 30 is a diagram showing a configuration of a light projecting section of an optical system of Example 11;

FIG. 31 is a diagram showing the overall structure of an optical system of Example 11;

FIG. 32 is a diagram showing how an object is irradiated in Example 11.

FIG. 33 is a diagram showing the appearance of spots.

FIG. 34 is a block diagram of a processing circuit according to the eleventh embodiment.

FIG. 35 is a diagram showing the appearance of spots in Example 12;

FIG. 36 is a diagram showing an effect of Example 12;

FIG. 37 is a block diagram of a processing circuit according to the twelfth embodiment.

[Explanation of symbols]

 1, 1a, 1b Light emitting element 2, 2a, 2b Light receiving element 3 Light emitting lens 4, 4a, 4b Light receiving lens 5, 7 Dichroic mirror 6 Mirror 12 Color sensor 13 Optical element

Claims (20)

[Claims] 1. A light projecting unit that emits at least two light fluxes having different optical axes toward an object, and receives reflected light of the two light fluxes reflected by the object through a condensing element or an opening. A light-receiving element divided into at least two regions, the light-receiving element being arranged so that the reflected light forms spots at different positions on the light-receiving element; An optical device, comprising: a distance measuring unit that measures a distance to an object based on the received light signal. 2. A light projecting unit that emits at least two light fluxes having different optical axes toward an object, and receives reflected light of the two light fluxes reflected by the object through a condensing element or an opening. A light-receiving element divided into at least two regions, the light-receiving element being arranged so that the reflected light forms spots at different positions on the light-receiving element; And an object detection unit that determines whether or not the object exists within a predetermined distance range based on the received light signal in 1. 3. The two spots formed on the light receiving element have a center of the spot which is divided into two parts.
2. One in each area.
Or the optical device according to 2. 4. The optical device according to claim 3, wherein the two spots formed on the light receiving element have the same distance from the dividing line of the light receiving element to the center of each spot. 5. The two spots formed on the light receiving element are characterized in that a moving direction of the spot when an object moves is substantially parallel to a dividing line of the light receiving element. The optical device described. 6. The light projecting section alternately emits a light beam, and the light receiving section processes a light receiving signal in synchronization with a timing at which the light beam is emitted. The optical device according to. 7. The optical device according to claim 1, wherein the light projecting unit emits two light beams having different optical axis directions. 8. The light projecting unit emits two light beams whose optical axes are shifted in parallel.
The optical device according to any one of 1. 9. The optical device according to claim 1, wherein the light projecting section includes two light emitting elements. 10. The light projecting unit comprises one light emitting element and a light beam separating means for separating a light beam emitted from the light emitting element into two light beams. The optical device according to any one of 1. 11. The optical device according to claim 1, wherein the light projecting unit emits two light beams having different wavelengths. 12. The optical device according to claim 1, wherein the light projecting unit emits two light beams having different polarizations. 13. The optical device according to claim 1, wherein the light projecting unit emits two light beams having different divergence angles. 14. The optical device according to claim 1, wherein the light receiving unit includes a color sensor divided into at least two regions. 15. The optical device according to claim 1, wherein the light receiving unit includes a divided light receiving element divided into at least four regions by three parallel dividing lines. apparatus. 16. The optical device according to claim 1, wherein the light receiving unit includes a divided light receiving element divided into at least three regions by two parallel dividing lines. apparatus. 17. The light receiving section comprises a divided light receiving element divided into at least four regions by two dividing lines intersecting with each other.
The optical device according to any one of 1. 18. A detection means for detecting whether or not the emitted light flux is correctly reflected by the target object based on the amount of received light of the reflected light from the target object for each of the two light fluxes. The optical device according to any one of claims 1 to 6, which is characterized. 19. A detection means for determining distance information for each of the two light fluxes, and detecting whether or not the distance information obtained for each light flux matches. 7. The optical device according to any one of 6 to 6. 20. The optical device according to claim 19, wherein the distance to the object is measured only when the distance information obtained for each light flux matches.