JP3490141B2 - External light triangular distance measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device, and more particularly to an external light triangular distance measuring device used in an autofocus camera or the like.

[0002]

2. Description of the Related Art First, the principle of a distance measuring device using the external light triangle method will be described. FIG. 6 is a schematic diagram showing an optical system of an external light triangulation distance measuring device. The light rays 51a and 51b emitted from the subject S have two equal lenses 52a and 5b.
After passing through 2b, the two sets of photosensors 53a and 53b in the distance measuring sensor module 54 are irradiated respectively. Two
By passing the two lenses 52a and 52b, the subject S
Two images are projected on the optical sensors 53a and 53b.

On the optical sensors 53a and 53b, two images are projected at a position where the length of the phase difference x is added from the base line length B, and the distance between the two images is (B + x). The baseline length B is the interval between two images projected on the optical sensors 53a and 53b via the two lenses 52a and 52b when the subject S is located at infinity.

The distance f between the lens and the sensor is equal to that of the lens 52.
An optical sensor 5 from which an optical image of a subject is projected from a and 52b
It is the distance to the surfaces 3a and 53b. The distance measurement value L is the distance from the subject S to the lenses 52a and 52b, and this distance is measured as the distance to the subject S.

Since a right-angled triangle having a base B and a height L is similar to a right-angled triangle having a base x and a height f, the distance measurement value L is calculated by the following equation: the base line length B and the lens-sensor distance f. Product of Bf
Is divided by the phase difference x.

L = (B · f) / x FIG. 7 is a schematic diagram showing the configuration of an optical module of a conventional external light triangulation distance measuring device. AF modules (lenses for autofocus) 6
2, the lens barrel 61, and a sensor module 63 having a semiconductor chip on which a pair of line sensors are formed can be divided into three parts. The AF lens 62 includes two equal lenses arranged at a predetermined interval B1 so that their optical axes are parallel to each other, and is fixed to the distance measuring sensor module 63 via the lens barrel 61. The light incident on the AF lens 62 passes through the lens barrel 61 and forms an image on the optical sensor in the sensor module 63.

The AF lens 62 and the lens barrel 61 are joined to each other at a joint portion 65.
The lens barrel 61 and the sensor module 63 are fixed to each other at the joints 66a and 66b with an adhesive. That is, the AF lens 62 and the lens barrel 61
And the three parts of the sensor module 63 include the joint 6
5a, 65b and the joining portions 66a, 66b are bonded in two stages.

In order to improve the accuracy of the distance measurement value L measured by this distance measuring device, it is desirable that the lengths B1, B2, f at the three locations do not change with time. The change with time is caused by a change in temperature or humidity. The length B1 is the distance between the two lenses included in the AF lens 62, and corresponds to the base line length B in FIG. The length B2 is determined by the sensor module 63
It is the distance between the two sets of optical sensors inside and corresponds to the baseline length B in FIG. The length f is the length between the AF lens 62 and the optical sensor in the sensor module 63.
Corresponds to the inter-sensor distance f.

The change over time of the length B1 is determined by the material of the AF lens 62, and the change over time of the length B2 is determined by the material of the sensor module 63. On the other hand, the change of the length f with time mainly depends on the AF lens 62 and the sensor module 6.
3, the material of the lens barrel 61 and the joint portion 65a,
It depends on the adhesive structure of 65b, 66a and 66b.

Therefore, it is necessary to prevent the length f from changing with time by using a highly rigid material for the lens barrel 61 holding the AF lens 62 and the sensor module 63. Ideally, all of the AF lens 62, the lens barrel 61, and the sensor module 63 should not expand or contract, but in reality, they will change slightly due to changes in temperature or humidity. In consideration of such thermal expansion, it is desirable that all three parts are made of materials having the same expansion coefficient and expand by the same amount due to changes in temperature and the like. For example, if only the length B1 becomes longer due to expansion and the lengths B2 and f do not change, the distance measurement value L with high accuracy cannot be obtained.

However, as described above, since the lens barrel 61 needs to have high rigidity to hold the AF lens 62 and the sensor module 63, a material having an expansion coefficient different from that of the AF lens 62 or the sensor module 63 is used. I had no choice. Therefore, there is a strong possibility that a difference in the expansion of each component will occur due to a change in the surrounding temperature or the like and an error will occur in the distance measurement value L.

[0012]

Since the lens barrel 61 in the conventional external light triangular distance measuring device holds the lens 62 and the sensor module 63, it is necessary to have high rigidity. If the rigidity of the lens barrel 61 is increased, the expansion rate of the lens barrel 61 must be different from that of the AF lens 62 and the sensor module 63. These differences in the expansion coefficient cause a decrease in distance measurement accuracy due to a change in the surrounding temperature.

Further, the three parts of the AF lens 62, the lens barrel 61 and the sensor module 63 are joined to each other by the joint portions 65a, 6a.
Since it is necessary to bond the 5b and the joints 66a and 66b in two steps, the process becomes complicated and the cost increases.

An object of the present invention is to provide an external light triangular distance measuring device capable of improving the positional accuracy between constituent parts.

[0015]

SUMMARY OF THE INVENTION An external light triangulation distance measuring device of the present invention is integrally molded and has a lens member having two optical lens portions, and is directly adhesively fixed to the lens member so that the two external members are externally attached. A light-receiving member having a light-receiving element for receiving light incident on the optical lens portion, and light that is tightly fixed to the lens member and the light-receiving member and is housed in an enclosed manner, and that enters the light-receiving element from other than the optical lens portion. And a lens barrel for shielding the object, and calculates the distance to the object according to the light amount distribution from the external object that passes through the two optical lens units and is irradiated on the light receiving element.

[0016]

[0017]

1 is a schematic view showing components of an optical module of an external light triangulation distance measuring device according to a reference example of the present invention. The components of the optical module are roughly classified into AF
It comprises a lens member 2, two lens barrel parts 1A and 1B, and a distance measuring sensor module 3.

The lens barrel parts 1A and 1B are completely the same in shape and made of one mold, and the lens barrel is constructed by combining the two parts 1A and 1B. Parts 1A, 1
B is assembled by sandwiching the AF lens member 2 in the middle.

The lens barrels 1A and 1B have the same shape, and the lower claw portion 1
0a and the upper hole 11b are respectively provided at the left ends when viewed from the inside of the lens barrels 1A and 1B, and the upper claw 10b and the lower hole 11a are provided.
Are provided at the right end of the lens barrel 1A and the left end of the lens barrel 1B, respectively. The two lower claw portions 10a provided at the left and right ends of the lens barrels 1A and 1B are fitted into the two opposing lower hole portions 11a, respectively. Further, the two left and right upper claw portions 10b are fitted into the two upper hole portions 11b facing each other.

The AF lens member 2 includes two lens portions 5a and 5b whose optical axes are parallel to each other, and includes lens barrel parts 1A and 1B.
Sandwiched between. A sandwiched between lens barrels 1A and 1B
The bottoms 12a and 12b of the F lens member 2 are adhered to the upper ends 13a and 13b of the sensor module 3, respectively, with an adhesive. The bonding is performed by applying an adhesive to the bonding surfaces 12a, 12b and 13a, 13b, superposing the adhesives on each other, aligning the AF lens member 2 and the sensor module 3 and then curing. An optical sensor 14 that receives light from a subject is embedded in the sensor module 3.

As described above, the AF lens member 2 and the lens barrel 1
The main fixing points of the parts of A, 1B and the sensor module 3 are two sets by adhesion and fitting. One is
Fixing the lens barrel component 1A and the lens barrel component 1B by the claw portions 10a and 10b and the hole portions 11a and 11b, and the other is AF.
The AF lens member 2 and the sensor module 3 are fixed by adhering the lens member bottoms 12a and 12b to the sensor module upper ends 13a and 13b.

Since the lens barrel parts 1A and 1B are fitted together, the AF lens member 2 is brought into close contact with the lens barrels 1A and 1B with almost no clearance, so that the lens barrel 1 is substantially used.
A and 1B are fixed to the AF lens member 2 and the sensor module 3. Therefore, it is possible to reduce the bonding process using the adhesive when fixing each component. However, bonding can also be performed.

Regarding the distance measurement accuracy, the positional accuracy between the AF lens member 2 and the sensor module 3 is required to be high, but the positions of the lens barrels 1A and 1B need to be high. Instead, it is sufficient if it can play the role of a lens barrel. The role of the lens barrel will be described later with reference to the drawings.

FIG. 2 is a sectional view of an optical module in which the components shown in FIG. 1 are assembled. The lens barrel component 1A shown in FIG.
The lens barrel configured by the combination of 1B is the diaphragm unit 1.
a, a lens barrel wall member 28, and a light blocking member 21.

The diaphragm 1a is provided above the AF lens member 2 as a part of the lens barrel in order to block light incident on the outer peripheral portion of the lens. The lens barrel wall member 28 is configured by fitting the claw portions 10a and 10b and the hole portions 11a and 11b shown in FIG.

The AF lens member 2 is bonded to the sensor module 3 at the joints 4a and 4b. In the conventional optical module of FIG. 7, it is necessary to bond two sets of the joints 65a and 65b and the joints 66a and 66b, whereas in the optical module according to the reference example of FIG. 2, the joints 4a and 4b are bonded. Since it is sufficient to bond only one set of
The bonding process can be reduced and the cost can be reduced.

Since the AF lens member 2 is directly adhered to the sensor module 3 without interposing the lens barrel, the positional accuracy is improved. Originally, the AF lens member 2 and the sensor module 3 can be made of materials having substantially the same expansion coefficient. Furthermore, since the parts can be directly bonded to each other, high positional accuracy can be realized.

Since the lens barrel no longer needs the function of holding the AF lens member 2 and the sensor module 3,
It is not always necessary to use a material having high rigidity. However,
In order to match the expansion of the AF lens member 2 and the sensor module 3, the lens barrel is preferably made of a material having an expansion coefficient close to that of the AF lens member 2 and the sensor module 3 regardless of the rigidity.

Next, consider two subjects S1 and S2.
The subject S1 is located in the distance measuring area 20, and
2 is located outside the distance measuring area 20. Throttle 1a
The light narrowed down by the light passes through the AF lens member 2.
The diaphragm area 1a of the lens barrel 1 determines the distance measuring area 20 of the distance measuring device.

The light ray 23a emitted from the subject S1 is
The optical image 25a is formed on the optical sensor 14 in the sensor module 3 through the one lens portion 5a of the AF lens member 2. The light ray 23b emitted from the subject S1 passes through the other lens portion 5b of the AF lens member 2 and the optical sensor 14
An optical image 25b is formed on the top.

On the other hand, a light ray 24 emitted from the subject S2
The light a passes through the lens portion 5a and is reflected by the lens barrel wall member 28, but is blocked by the stray light prevention member 22 and the optical sensor 1
It doesn't reach 4. In this way, the stray light prevention member 22 is
It prevents light incident from the outside of the distance measuring area 20 from being reflected by the lens barrel wall member 28 and reaching the optical sensor 14 (prevention of stray light).

Further, a light ray 24 emitted from the subject S2
After passing through the lens portion 5b, b is shielded by the stray light prevention member 22 provided in the light shielding member 21. Shading member 2
1, the light ray 24b which is emitted from the subject S2 and is incident on one lens portion 5b of the AF lens member 2 and the light ray 23a which is emitted from the subject S1 and is incident on the other lens portion 5a are overlapped, and are combined on the optical sensor 14. It has a function to prevent images.

FIG. 3 is a schematic view for explaining an adverse effect of an optical module using a lens barrel without a stray light prevention member. The light rays 23a and 23b emitted from the subject S1 in the distance measuring area 20 respectively pass through the AF lens member 2 and the optical sensor 14 in the sensor module 3 as described above.
The light images 25a and 25b are formed on the top.

On the other hand, the light rays 24a and 24b emitted from the subject S2 outside the distance measuring area 20 pass through the lens portions 5a and 5b of the AF lens member 2, respectively, and the lens barrel wall portion 28 '.
And is formed as optical images 27a and 27b on the optical sensor 14.

Since the light images 27a and 27b overlap the light images 25a and 25b of the subject S1, it is impossible to accurately extract the light images 25a and 25b of the subject S1, which is the original measurement target. Therefore, the accurate subject S1
It is impossible to measure the distance measurement value L up to.

As described above, the stray light prevention member 22 shown in FIG. 2 is required to block the light reflected on the inner surface of the lens barrel wall portion 28 '. FIG. 4 is a schematic diagram for explaining an adverse effect of an optical module using a lens barrel having no light blocking member.

Light rays 23a and 23b emitted from the subject S1 in the distance measuring area 20 are respectively detected by the AF
Optical images 25a and 25b are formed on the optical sensor 14 in the sensor module 3 via the lens portions 5a and 5b of the lens member 2.

On the other hand, a light ray 24 emitted from the subject S2
Since b does not have a light blocking member, it is directly formed as an optical image 26 on the optical sensor area via the lens portion 5b of the AF lens member 2.

The light ray 24a emitted from the subject S2 outside the distance measuring area 20 does not have a stray light preventing member, so that the lens barrel wall member 2 passes through the lens portion 5a of the AF lens member 2.
8'is reflected internally and is formed as an optical image 26 on the optical sensor 14.

The light image 26 is the light image 2 of the subject S1.
Since it overlaps 5a and interferes with the extraction of the optical image 25a, it becomes impossible to measure the accurate distance measurement value L. As described above, in order to prevent the light incident from one lens portion 5b of the AF lens member 2 from being mixed with the light incident from the other lens portion 5a to form an optical image on the optical sensor 14, The light shielding member 21 shown in 2 is required.

The lens barrel is made of an opaque member such as black having a low transmittance and a low reflectance in order to shield light or prevent stray light. On the other hand, since the AF lens member has a lens portion that allows light to pass therethrough, it is made of a transparent member.

The lens barrel is not limited to the shape shown in FIG. 2, and it is sufficient that it has the functions of preventing stray light and shielding the other optical sensor as described above, and the AF lens member 2 and the sensor. Since it is not necessary to hold the module 3, the rigidity may be high or low.

FIG. 5 is a schematic view showing components of an optical module of the external light triangulation distance measuring device according to the embodiment. The AF lens member 32 is one of the hexahedrons with a hollow inside.
It has a shape in which only the surface becomes an opening. 2 on 1 of 6 faces
Individual lenses 35a and 35b are provided, and an opening 40 is provided on the opposing surface thereof. The remaining four sides are covered with walls.

The lens barrel part 31A and the lens barrel part 31B are inserted into the cavity of the AF lens member 32 through the opening 40 in combination. The lens barrel parts 31A and 31B have the same shape, are assembled facing each other, and fit into the AF lens member 32 with almost no space.

The lens barrels 31A and 31B are attached to the AF lens member 32.
After being fitted into the inside, the AF lens member 32 and the distance measuring sensor module 33 are bonded. The adhesion is performed by the end surfaces 36a and 36b of the AF lens member 32 and the sensor module 33.
The adhesive is applied to the end faces 38a and 38b of the above, and the end faces 38a and 38b are superposed and then cured. Further, the end surfaces 37a and 37b of the AF lens member 32 may be adhered to the end surfaces 39a and 39b of the sensor module 33, respectively.

Lens parts 35a, 3 of the AF lens member 32
The light entering 5b passes through the inside of the lens barrels 31A and 31B and reaches the sensor module 33. As described above, in the optical module of the present embodiment, the AF lens member and the sensor module are directly bonded and fixed without interposing the lens barrel, so that high position accuracy can be realized.
Further, since it is not necessary to bond the lens barrel and the AF lens member to each other and only the AF lens member and the sensor module need to be bonded to each other, it is resistant to temperature changes and the like, and the cost can be reduced by reducing the bonding process.

Since the lens barrel is composed of two parts of the same shape, it can be easily manufactured by using one mold.
The cost can be reduced. Although the present invention has been described above with reference to the embodiments, the present invention is not limited thereto. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0048]

As described above, according to the present invention,
Since the lens member having the two optical lens portions is directly bonded and fixed to the light receiving member, the lens barrel does not need to support and fix the two of the lens member and the light receiving member, and it is not necessary to consider the rigidity of the material. Further, since the lens member and the light receiving member are directly adhered and fixed, the positional accuracy of the optical lens portion of the lens member and the light receiving member is improved, and highly accurate distance measurement can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view showing components of an optical module of an external light triangulation distance measuring device according to a reference example of the present invention.

FIG. 2 is a cross-sectional view of the assembled optical module of the present embodiment.

FIG. 3 is a cross-sectional view of an optical module using a lens barrel without a light prevention member.

FIG. 4 is a cross-sectional view of an optical module using a lens barrel without a light blocking member.

FIG. 5 is a perspective view showing components of the optical module of the external light triangulation distance measuring device according to the embodiment.

FIG. 6 is a schematic diagram showing the principle of an external light triangular optical system.

FIG. 7 is a cross-sectional view showing a configuration of an optical module of a conventional external light triangulation distance measuring device.

[Explanation of symbols]

1A, 1B lens barrel 1a throttle part 2 AF lens member 3 Sensor module for distance measurement 4a, 4b joint 5a, 5b lens part 10a, 10b claws 11a, 11b holes 14 Optical sensor S1, S2 subject 20 ranging area 21 Light-shielding member 22 Stray light prevention member 28 Lens barrel wall member 23a, 23b, 24a, 24b rays 25a, 25b, 26, 27a, 27b Optical image 31A, 31B lens barrel 32 AF lens member 33 Distance measuring sensor module 35a, 35b lens part 40 opening S subject 51a, 51b rays 52a, 52b lens 53a, 53b Optical sensor 54 sensor module 62 AF lens 63 Distance measuring sensor module

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-303032 (JP, A) JP-A-54-40663 (JP, A) JP-A-3-157602 (JP, A) JP-A-54- 61522 (JP, A) Fukukaihei 2-39221 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01C 3/00-3/32 G01B 11/00-11/30 102 G02B 7/28-7/40 G03B 13/32-13/36

Claims (3)

(57) [Claims] 1. A light receiving member having a lens member integrally molded and having two optical lens portions, and a light receiving element that is directly adhered and fixed to the lens member and that receives light incident on the two optical lens portions from the outside. And a lens barrel that is tightly fixed to the lens member and the light receiving member, is enclosed and housed, and shields light that enters the light receiving element from a portion other than the optical lens portion. An external light triangular distance measuring device that calculates a distance to an object according to a light amount distribution from an external object that passes through a lens unit and is irradiated on the light receiving element. 2. The external light triangular distance measuring device according to claim 1, wherein the lens member has a transparent color and the lens barrel has an opaque color. 3. The external light triangular distance measuring device according to claim 1, wherein the lens barrel is arranged by combining two light blocking members of the same shape between the optical lens portion and the light receiving element.