JPH05273447A - Optical system assembly - Google Patents

Abstract

PURPOSE:To decrease an error in the positional relationship between a lens and an optical axis by mounting the plane part of the lens on a plane substrate and arranging the lens on the plane substrate with a positioning plate. CONSTITUTION:A metallic fixture 8 equipped with a 1st lens 3, and 2nd and 3rd lenses 4 and 5 have plane parts 9, which are parallel to the optical axis, at a constant distance from the optical axis. The respective plane parts 9 are polished by a plane polishing board and the metallic fixture 8 equipped with the 1st lens 3 and the 2nd and 3rd lenses 4 and 5 have their plane parts 9 formed in the plane polishing board so that their optical axes are parallel to a table slide surface. Respective optical system elements installed on the plane substrate 2 are arranged accurately at prescribed positions on the top surface of the plane substrate 2 with the positioning plate 10 mounted on the top surface of the plane substrate 2. The respective optical system elements are fixed to the plane substrate 2 with an adhesive.

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 assembled in a passage for light such as laser light and visible light.

[0002]

2. Description of the Related Art An example of a conventional optical system assembly is shown in FIG. Lens 102 used in conventional optics assembly 101
Are circular and are held in a cylindrical case (lens barrel) 103. The position of the lens 102 in the lens barrel 103 is determined by the projection 104 formed on the inner circumference of the lens barrel 103 and the lens barrel 103.
It is held by a spacer 105 disposed inside.

[0003]

[Problems to be Solved by the Invention] Conventional optical system assembly 10
1 is because the lens 102 is placed in the cylindrical lens barrel 103,
A clearance for housing the lens 102 exists between the lens 102 and the lens barrel 103. Therefore, the centers of the lens 102 and the lens barrel 103 do not coincide with each other, and a slight error occurs in the positional relationship between the lens 102 and the optical axis. Also, when replacing the lens 102, when replacing the lens 102 in the inner part of the lens barrel 103, there is a problem that the lens 102 cannot be replaced unless the front lens 102 and other filters are removed. Further, since high accuracy is required for the inner circumference of the lens barrel 103, the conventional optical system assembly 101 has a problem of high cost.

[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 one holding the lens and to eliminate an error in the positional relationship between the lens and the optical axis. It is to provide an optical system assembly that can be eliminated more.

[0005]

An optical system assembly of the present invention comprises a lens having a plane portion parallel to the optical axis direction,
A flat substrate on which the flat portion of the lens is placed, and a positioning plate placed on the flat substrate to keep the flat portion of the lens on the flat substrate in a correct position Adopted technical means.

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

[0007]

In the optical system assembly having the above-described structure, the flat portion of the lens is placed on the flat substrate, and the positioning plate properly positions the lens on the flat substrate. Therefore, the lens and the flat substrate that holds the lens can be accurately assembled, and the error in the positional relationship between the lens and the optical axis can be made smaller than in the conventional case.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical system assembly of the present invention will be described based on an embodiment shown in the drawings.

[Configuration of Embodiment] 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. Indicates. The 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 flat substrate 2 having a plate shape. 7 and 7 constitute a sensor part of an optical machine. 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, 5 are made of glass or resin.

The fixture 8 provided with the first lens 3 and the second and third lenses 4 and 5 are each provided with a flat surface portion 9 parallel to the optical axis direction at a position at a constant distance from the optical axis. Each flat surface portion 9 is polished and formed by a flat surface polishing plate (not shown), and is provided with the fixture 8, the second,
The third lenses 4 and 5 are installed on a flat polishing machine such that their optical axes are parallel to the table sliding surface, and a flat surface portion 9 is formed. The fixture 8, the second and third lenses 4, 5
When the resin is molded with a resin, for example, the outer diameter is formed in a rectangular shape so that the center is the optical axis.

Each optical system element installed on the flat substrate 2 is
Positioning plate 10 placed on the surface of the flat substrate 2
Are accurately arranged at a prescribed position on the upper surface of the flat substrate 2. The positioning plate 10 of this embodiment is
Notch 11 matching the shape of the flat surface portion 9 of each optical system element
Is a thin plate with the correct mounting position. The cutout 11 may be replaced by a hole in which the flat surface portion 9 is arranged. Further, the positioning plate 10 may be provided so as to be removed from the flat substrate 2 after fixing each optical element to the flat substrate 2.

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

Next, an example of a method of forming the flat surface portion 9 using a polishing plate will be described. On a table of a flat polishing machine, a workbench that can be rotated and moved in parallel is provided with a fixture 8 for polishing, the second lens 4 or the third lens 5 on one side, and a standard concave mirror (f value of which can be raised and rotated) on the other Attach the expected height of the optical axis. Then, a HeNe laser beam for inspection is projected on a standard concave mirror through a band-shaped screen having a horizontal mark at the height of the optical axis and a hole of 1 mmφ at one point on the mark. The workbench is rotated and moved back and forth to adjust the tilt between the concave mirror and the laser light so that the reflected light point is always on the screen mark line. At this time, the laser light is parallel to the table at a predetermined height of the optical axis. By providing a differential photodetector on 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 to be polished or the fixture 8 is adjusted so that the reflected light and the focus position from one surface of the polishing target are on the mark line of the screen regardless of the rotation and movement of the workbench. .. At this time, the optical axis of the object to be polished is parallel to the table at the height of the planned optical axis. Then, the surface parallel to the optical axis is polished at a distance from the predetermined 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 fixture 8 having the first lens 3 which is an optical element, 2, third lens 4, 5, wave plate 6 and reflector 7
Can be accurately attached to the surface of the flat substrate 2,
The error between the optical axis and each optical element can be eliminated as compared with the conventional case. It should be noted that increasing the accuracy of the positioning plate 10 is much easier than increasing the accuracy of the lens barrel that has been conventionally used. Therefore, the optical system assembly 1 with high accuracy can be obtained at low cost. Further, in the related art, since the lens barrel is required to have high accuracy, it is difficult to reduce the wall thickness and the size is increased. However, the present embodiment has a flat substrate 2 on which an optical element is mounted. Since high precision is not required, the optical system assembly 1 can be made thinner and lighter than the conventional one.

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

A second embodiment is shown in FIGS. The fixture 8, the wave plate 6 and the reflector 7 including the first lens 3 including the second and third lenses 4 and 5 of the present embodiment have the second flat surface portion 12 parallel to the flat surface portion 9, respectively. Prepare Then, each second flat surface portion 12 is fixed by the upper plate 13 to the fixing screw 14
The optical element is pressed against the flat substrate 2 by means of to fix each optical element to the flat substrate 2. The upper plate 13 can also serve as a case of an optical machine or a circuit board of an electronic circuit of an optical instrument.

A third embodiment is shown in FIGS. 6 to 11. This embodiment is used for the sensor portion of a Doppler measuring instrument, and has a holder 16 to which a semiconductor laser 15 is attached, a collimator lens 17, a reflecting mirror with an analytical grating 18, a first reflecting mirror 19, and a two-lens lens 20. , 21, a photodetector 22, and a second reflecting mirror 23, and measures a measurement object through a measurement window 24 formed on the side wall of the upper plate 13. Then, as shown in the present embodiment, the optical system assembly 1 of the present invention.
Since it is possible to easily bend light, it becomes easy to dispose the optical system assembly 1 in a narrow space.

[Brief description of 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 an 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 an 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 cross-sectional view of the optical system assembly.

8 is a cross-sectional view taken along the line aa of FIG.

9 is a cross-sectional view taken along the line bb of FIG.

10 is a cross-sectional view taken along the line cc of FIG.

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

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

[Explanation of symbols]

 1 Optical System Assembly 2 Flat Substrate 3 First Lens 4 Second Lens 5 Third Lens 9 Plane 10 Positioning Plate 12 Second Plane 13 Upper Plate

Claims (3)

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