JP3026846B2 - Optical system assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system assembly in which a lens is attached to a path of light such as laser light or visible light.

[0002]

2. Description of the Related Art FIG. 12 shows an example of a conventional optical system assembly. Lens 102 used in conventional optical system assembly 101
Are held in a circular, cylindrical case (barrel) 103. The position of the lens 102 in the lens barrel 103 is determined by the protrusion 104 formed on the inner circumference of the lens barrel 103 or the lens barrel 103.
Is maintained by spacers 105 disposed therein.

[0003]

SUMMARY OF THE INVENTION A conventional optical system assembly 10
1 is because the lens 102 is disposed in the cylindrical lens barrel 103,
There is a clearance between the lens 102 and the lens barrel 103 for housing the lens 102. For this reason, the centers of the lens 102 and the lens barrel 103 do not coincide, and a slight error occurs in the positional relationship between the lens 102 and the optical axis. Also, when replacing the lens 102, the lens 102 located in the back of the lens barrel 103 cannot be replaced without removing the front lens 102 and other filters. Further, since high accuracy is required for the accuracy of the inner circumference of the lens barrel 103, the conventional optical system assembly 101 has a problem that the cost is increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately assemble a lens and a lens holding lens, and to reduce the positional error between the lens and the optical axis. An object of the present invention is to provide an optical system assembly that can be eliminated.

[0005]

According to the present invention, there is provided an optical system assembly comprising: a lens having a flat portion parallel to an optical axis direction;
A flat substrate on which the flat portion of the lens is mounted, and a positioning plate placed on the flat substrate and maintaining the flat portion of the lens mounted on the flat substrate at a correct position. Technical measures were adopted.

The positioning plate of the optical system assembly according to the present invention can employ the following embodiments. After fixing the lens to the flat substrate, the positioning plate is removed.
Alternatively, a second flat portion parallel to the flat portion is provided on the lens, and the lens is fixed to the flat substrate by an upper plate that presses the second flat portion toward the flat substrate.

[0007]

In the optical system assembly having the above-mentioned structure, the flat portion of the lens is mounted on the flat substrate, and the lens position is correctly arranged on the flat substrate by the positioning plate. Therefore, it is possible to accurately assemble the lens and the flat substrate holding the lens, and to reduce the error in the positional relationship between the lens and the optical axis as compared with the related art.

[0008]

Next, an optical system assembly according to the present invention will be described with reference to an embodiment shown in the drawings.

FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a side sectional view of an optical system assembly, and FIG. 2 is a top view of the optical system assembly. Is shown. An optical system assembly 1 according to the present embodiment includes a first lens 3, second and third lenses 4 and 5 according to the present invention, a wave plate 6, and a reflection plate on an upper surface of a planar substrate 2 having a plate shape. 7 constitutes a sensor part of an optical machine equipped with. The first lens 3 at the left end in the figure is a small-diameter lens that receives the light of the semiconductor laser.
It is embedded and held in a hole provided in the fixture 8. The first, second, and third lenses 3, 4, and 5 are made of glass or resin.

The fixture 8 having the first lens 3 and the second and third lenses 4 and 5 each have a plane portion 9 at a fixed distance from the optical axis and parallel to the optical axis direction. Each flat portion 9 is polished and formed by a flat polisher (not shown), and is provided with a fixture 8 having the first lens 3, a second
The third lenses 4 and 5 are respectively set on a flat polishing machine such that the optical axis is parallel to the table sliding surface, and a flat portion 9 is formed. The attachment 8, the second and third lenses 4, 5,
Is molded with a resin, for example, the outer diameter is formed in a rectangular shape so that the center becomes the optical axis.

Each optical system element installed on the plane substrate 2
Positioning plate 10 placed on the surface of planar substrate 2
Thereby, it is accurately arranged at a predetermined position on the upper surface of the planar substrate 2. The positioning plate 10 of the present embodiment includes:
Notch 11 conforming to the shape of plane portion 9 of each optical system element
Is a thin plate provided in a correct mounting position. In addition, instead of the notch 11, a hole in which the plane portion 9 is arranged may be used. Further, after fixing each optical element to the plane substrate 2, the positioning plate 10 may be provided so as to be removed from the plane substrate 2.

Each optical system element of this embodiment is fixed to the flat substrate 2 by an adhesive.

Next, an example of a method of forming the flat portion 9 using a polishing machine will be described. On a table of a plane polishing machine, a fixture 8 for polishing and a second lens 4 or a third lens 5 are mounted on one side of a worktable that can be rotated and moved in parallel, and a standard concave mirror (f value is feasible) that can be rotated and rotated on the other side. (Planned optical axis height). Next, a HeNe laser beam for inspection is projected onto a standard concave mirror through a band-shaped screen having a horizontal mark at the height of the optical axis and having a hole of 1 mmφ at one point on the mark. The tilt of the concave mirror and the laser beam is adjusted by rotating and moving the work table back and forth so that the reflected light point is always on the screen mark line. At this time, the laser beam is parallel to the table at a predetermined height of the optical axis. By providing a differential photodetector in a part of the mark line, the optical axis setting accuracy can be increased to 0.01 mm. Then, the mounting position of the lens or the mounting tool 8 as the object to be polished is adjusted so that the reflected light and the focal position from one surface of the object to be polished are on the mark line of the screen regardless of the rotation or movement of the worktable. . At this time, the optical axis of the object to be polished is parallel to the table at the height of the predetermined optical axis. Then, a surface parallel to the optical axis is polished at a predetermined distance from the optical axis.

[Effects of the Embodiment] In the optical system assembly 1 shown in this embodiment, by increasing the accuracy of the positioning plate 10, the mounting fixture 8 having the first lens 3 as an optical element, 2, third lenses 4, 5, wavelength plate 6, and reflection plate 7
Can be accurately attached to the surface of the planar substrate 2,
An error between the optical axis and each optical element can be eliminated as compared with the related art. It is much easier to increase the accuracy of the positioning plate 10 than to increase the accuracy of a lens barrel used conventionally. Therefore, the optical system assembly 1 with high accuracy can be obtained at low cost. Conventionally, the lens barrel is required to have high accuracy, so that it is difficult to make the lens barrel thinner and has a problem that the lens barrel becomes larger. However, in this embodiment, the flat substrate 2 on which the optical element is mounted is provided. Since high precision is not required, the optical system assembly 1 can be made thinner, and as a result, the optical system assembly 1 can be reduced in size and weight as compared with the related art.

In addition, each optical element can be detached independently,
Since they can be fixed, the optical elements can be easily exchanged and adjusted even after the optical system assembly 1 is assembled.

FIGS. 3 to 5 show a second embodiment. The fixture 8, the wavelength plate 6, and the reflection plate 7 provided with the first lens 3 including the second and third lenses 4, 5 of the present embodiment each have a second plane portion 12 parallel to the plane portion 9. Prepare. Then, each second flat portion 12 is fixed by an upper plate 13 with a fixing screw 14.
Is pressed toward the flat substrate 2 to fix each optical element to the flat substrate 2. In addition, the upper plate 13 can also serve as a case of an optical machine or a circuit board of an electronic circuit of the optical instrument.

FIGS. 6 to 11 show a third embodiment. This embodiment is used for a sensor part of a Doppler measuring instrument, and includes a holder 16 to which a semiconductor laser 15 is attached, a collimator lens 17, a reflecting mirror 18 with an analysis grid, a first reflecting mirror 19, and two assembled lenses 20. , 21, a photodetector 22 and a second reflecting mirror 23 for measuring a measurement object from a measurement window 24 formed on a side wall of the upper plate 13. Then, as shown in the present embodiment, the optical system assembly 1 of the present invention
Since the light can be easily bent, it is easy to dispose the optical system assembly 1 in a narrow space.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an optical system assembly according to a first embodiment.

FIG. 2 is a top view of the optical system assembly.

FIG. 3 is a perspective view of an optical system assembly according to a second embodiment.

FIG. 4 is a side sectional view of the optical system assembly.

FIG. 5 is a top view of the optical system assembly.

FIG. 6 is a perspective view of an optical system assembly according to a third embodiment.

FIG. 7 is a top sectional view of the optical system assembly.

FIG. 8 is a sectional view taken along the line aa in FIG. 7;

FIG. 9 is a sectional view taken along line bb in FIG. 7;

FIG. 10 is a cross-sectional view along the line cc in FIG. 7;

FIG. 11 is a side view of the optical system assembly.

FIG. 12 is a sectional view of an example of a conventional optical system assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical system assembly 2 Flat board 3 1st lens 4 2nd lens 5 3rd lens 9 Flat part 10 Positioning plate 12 2nd flat part 13 Upper plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-310510 (JP, A) JP-A-63-80515 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 7/00

Claims (3)

(57) [Claims] (A) a lens having a plane portion parallel to the optical axis direction; (b) a flat substrate on which the flat portion of the lens is mounted; and (c) a flat substrate on the flat substrate. An optical system assembly comprising: a positioning plate that is placed and that keeps the flat portion of the lens placed on the flat substrate in a correct position. 2. The optical system assembly according to claim 1, wherein the positioning plate is removed after fixing the lens to the flat substrate. 3. The lens has a second flat portion parallel to the flat portion, and the lens is fixed to the flat substrate by an upper plate that presses the second flat portion toward the flat substrate. The optical system assembly according to claim 1.