JP3127003B2 - Aspherical lens eccentricity measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aspherical lens eccentricity measuring method for measuring the eccentricity of an aspherical lens.

[0002]

2. Description of the Related Art Conventionally, as an eccentricity measuring device for an aspherical lens, Japanese Patent Application Laid-Open No. 1-296132 previously submitted by the present applicant has been proposed.
There is an official gazette.

[0003] As shown in FIG.
Is a rotation holder (rotated and driven via a rotation drive unit not shown) 73 for rotatably holding the test lens 72, and a rotation axis 74 of the paraxial curvature center 72c of the first surface 72a. A paraxial eccentricity measuring unit 75 for detecting the amount of eccentricity with respect to the axis, and an aspherical axis measuring unit 77 for measuring the inclination angle ε _1AS of the aspherical axis 76 of the first surface 72 a with respect to the rotation axis 74 I have.

The contact portion of the rotating holder 73 with the lens 72 to be tested is machined concentrically with respect to the rotating shaft 74. Reference numeral 78 denotes the detection axis of the aspherical axis, and reference numeral 72d denotes the center of curvature of the second surface 72b which is a spherical surface.

In the above configuration, when the rotation holder 73 is rotated while the test lens 72 is supported by the rotation holder 73, the center of curvature 72 of the second surface 72 b of the test lens 72.
d is theoretically aligned so that it is always on the axis of the rotating shaft 74.

Further, the eccentricity of the paraxial curvature center 72c of the first surface 72a with respect to the rotation axis 74 is detected by the paraxial eccentricity measuring section 75, and the lens 7 to be measured is set so that the eccentricity becomes zero.
By adjusting the position 2, the center of curvature 72c of the first surface 72a can be made coincident with the axis of the rotating shaft 74 in the same manner as the center of curvature 72d of the second surface 72b.

Therefore, the paraxial center of curvature 72 of the first surface 72a
Assuming that a straight line connecting c and the center of curvature 72d of the second surface 72b is the reference axis of the lens 72 to be measured, this reference axis is the rotation axis 7
Matches 4.

Here, the rotation axis 7 is measured by the aspherical axis measurement unit 77.
The inclination angle ε of the aspherical axis 76 of the first surface 72a with respect to
_{When 1AS} is measured, the inclination angle ε _1AS is the inclination angle of the aspherical axis 76 with respect to the reference axis, and the inclination ε of the aspherical axis 76 with respect to the reference axis when the second surface 72b is spherical and the first surface 72a is aspherical. _1AS can be measured.

Similarly, the first surface 72a and the second surface 7
When both 2b are aspherical surfaces, similarly to the first surface, the second surface 7
The inclination of the aspherical axis of 2b can be measured.

Further, even when the second surface 72b is a flat surface, the inclination ε _1AS can be measured by using the perpendicular to the second surface passing through the paraxial curvature center 72c of the first surface 72a as the reference axis.

[0011]

However, the above prior art has the following problems.

That is, since the measurement of the aspherical axis is performed by the aspherical axis measuring unit, a complicated calculation is required based on the detected value of the spherical position, and the measurement takes a long time as a whole.

Accordingly, the present invention has been developed in view of the above-mentioned problems in the prior art, and has as its object to provide an aspherical lens eccentricity measuring method capable of performing measurement in a short time.

[0014]

SUMMARY OF THE INVENTION The present invention relates to an aspherical lens having two flat surfaces formed coaxially and integrally with two optical surfaces forming an aspheric lens. In this method, an inclination angle to be formed and an eccentric amount of the two optical surfaces with respect to a measurement axis are detected, and an eccentric amount of the aspherical lens is calculated and obtained from the detected values.

FIG. 1 is a conceptual diagram showing a method for measuring decentering of an aspherical lens according to the present invention.

1 is a measurement axis, and 2 is a reference plane orthogonal to the measurement axis 1. Reference numeral 3 denotes an upper optical surface which is an aspherical surface.
₁ indicates its paraxial center of curvature. Numeral 4 denotes a lower optical surface which is an aspherical surface, and 0 ₂ denotes its paraxial center of curvature.

Here, the distance from 0 ₁ and 0 ₂ is given as a design value L. 5 is an upper flat portion formed around the upper optical surface 3 by being integrally formed with the upper optical surface 3 by the same mold, and 6 is formed by integrally forming the lower optical surface 4 with the same die. The lower flat portion formed around the surface 4.

[0018] 7 is a straight line passing through the paraxial curvature center 0 ₂ of the paraxial curvature center 0 ₁ of the upper optical surface 3 and the lower optical surface 4, hereinafter called the straight line and the optical axis 7.

Reference numerals 8 and 9 denote aspherical axes of the upper optical surface 3 and the lower optical surface 4, respectively. The upper aspherical axis 8 and the lower aspherical axis 9 are paraxial centers of curvature 0 _{1 of the} upper optical surface 3, respectively. and through the paraxial curvature center 0 ₂ of the lower optical surface 4.

First, in a state where the lower flat portion 6 is aligned with the reference surface 2, a method such as an autocollimation method is used.
Eccentric shift amount with respect to the measurement axis 1 of paraxial curvature center 0 ₂ of the paraxial curvature center of the upper optical surfaces 3 0 ₁ and lower optical surfaces 4 [delta] ₁
And δ ₂ , and the inclination angle ε of the upper flat portion 5 with respect to the lower flat portion 6 is also measured by a method such as the autocollimation method.

From these measured values and the distance L, the inclination angles ε ₁ and ε ₂ of the upper surface aspherical axis 8 and the lower surface aspherical axis 9 with respect to the optical axis 7 can be obtained by the following equations ( 1) and (2). it can.

[0022]

(Equation 1)

[0023]

(Equation 2)

Equations ( 1) and (2) are for the case where both sides are aspherical. If one side is a plane, the center of the paraxial curvature exists at infinity.

In this case, the inclination angle of the aspherical axis on the aspherical surface side can be obtained by defining the straight line passing through the paraxial curvature center of another aspherical surface and perpendicular to the plane as the optical axis. .

[0026]

Embodiment 1 FIG. 2 is an explanatory view showing this embodiment.

In FIG. 2, the same portions as those in FIG. 1 are denoted by the same reference numerals and symbols, and description thereof will be omitted.

[0028] In this embodiment is for measuring the ε and [delta] ₁ of the aforementioned measured from above by autocollimator 11 by autocollimation method, a [delta] ₂ also from below autocollimator 12 by autocollimation method .

More specifically, when the measurement axis 1 of the lens to be inspected is rotated about the rotation axis, the reflection images corresponding to δ ₁ , δ ₂ and ε are rotated. Find δ ₁ , δ ₂ and ε.

According to this embodiment, measurement can be performed with high accuracy.

[0031]

EXAMPLE 2 In this embodiment, by moving the sample lens in Example 1 along the reference surface, after the manner detected value of [delta] ₂ is zero, measuring the [delta] ₁ and epsilon.

According to this embodiment, more accurate measurement can be performed as compared with the first embodiment.

[0033]

Embodiment 3 FIG. 3 is an explanatory view showing this embodiment.

In FIG. 3, the same parts as those in FIG. 2 are denoted by the same reference numerals and symbols, and description thereof will be omitted.

Reference numeral 21 denotes a line of intersection between the upper optical surface 3 and the upper plane portion 5, and reference numeral 22 denotes an autocollimator used only for detecting ε. Reference numeral 23 denotes a microscope for detecting the position of the intersection line 21.

In this embodiment, the amount of shake of the image of the intersection line 21 due to the rotation of the lens to be inspected is detected by the microscope, and the amount of eccentricity δ of the center of the intersection line 21 with respect to the measurement axis is determined from the shake amount. And the paraxial center of curvature 0 of the upper optical surface 3 from the intersection of the plane including the upper plane portion 5 and the upper surface aspherical axis 8.
The following equation 3 by introducing the distance L ₁ of the design value of up to _1,
δ ₁ can be determined.

[0037]

(Equation 3)

[0038] The [delta] ₁ of the value and _second value [delta] obtained with the auto collimator 12 and the number 1 and number 2 epsilon ₁ and epsilon
You can ask for ₂ .

According to this embodiment, the measurement time can be further shortened than in each of the above embodiments.

[0040]

As described above, according to the aspherical lens eccentricity measuring method according to the present invention, only the geometric analysis of the plane, that is, the eccentric shift of the paraxial center of curvature of the two optical surfaces with respect to the measuring axis. The measurement time can be shortened by obtaining the aspherical eccentric amount only by measuring the amounts δ ₁ and δ ₂ and the angle (tilt angle) ε between the two plane portions.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating the present invention.

FIG. 2 is an explanatory diagram illustrating a first embodiment;

FIG. 3 is an explanatory diagram showing a third embodiment.

FIG. 4 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measurement axis 2 Reference surface 3 Upper optical surface 4 Lower optical surface 5 Upper flat surface 6 Lower flat surface 7 Optical axis 8 Upper surface aspherical axis 9 Lower surface aspherical axis

(Equation 1)

(Equation 2)

(Equation 3)

──────────────────────────────────────────────────続 き Continued on the front page (72) Haruo Ogawa, Inventor 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside O-limpus Optical Industries Co., Ltd. (72) Nobuyoshi Iwasaki 2-43-2, Hatagaya, Shibuya-ku, Tokyo No. Ohlympus Optical Co., Ltd. (72) Inventor Shigeya Sugita 2-43-2 Hatagaya, Shibuya-ku, Tokyo In-Olympus Optical Industry Co., Ltd. (72) Mitsuo Goto 2-43, Hatagaya, Shibuya-ku, Tokyo No. 2 Inside Olympus Optical Co., Ltd. (72) Inventor Takeshi Kawamata 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) References JP-A-1-296132 (JP, A) JP-A-61-53602 (JP, A) JP-A-3-115944 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 11/00-11/02

Claims (1)

(57) [Claims] 1. An aspherical lens having two flat surfaces formed coaxially and integrally with two optical surfaces forming an aspherical lens, respectively, and an inclination angle between the two flat surfaces and the two optical surfaces. A method for measuring eccentricity of an aspherical lens, comprising detecting an eccentricity with respect to a measurement axis, and calculating an eccentricity of the aspherical lens based on the detected values.