JPS5928639A - Lens meter and target plate therefor - Google Patents

Abstract

PURPOSE:To measure the cylindric axis of a lens to be examined with good accuracy, by using the pattern of two parallel dotted straight line groups as a target pattern of a target plate and specifying the diameter of the dot pattern constituting dotted straight lines and the space between the dotted straight lines. CONSTITUTION:A pattern 2 of dotted straight line groups is formed on a target plate 1. The respective diameters of the dot pattern are hT given by the equation and the space between the dotted straight lines is 2hT, if the focal lengths of the collimator lens and objective lens of a lens meter are designated as f1, f2, respectively, the diameter of the effective luminous flux to be used as phi and the min. measuring cylindricity of the lens to be examined as C. If a lens 8 to be examined is disposed in the measuring optical path and is focused to the 1st cylindric axis 6, the dot pattern of a target observation image is the linear image flowing in parallel with the axial direction theta1 of the 1st cylindric axis 6. The target plate is rotated to match the end parts of the dot pattern image and the direction theta1 is read by using a scale plate 9. The target plate is moved on the optical axis to match the dot pattern image with the other dot pattern image of the same dotted straight line and is focused to the 2nd cylindric axis 7, then the axial direction theta2 is read by making use of the dotted straight line images 2a', 2b'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens meter for measuring the refractive properties of eyeglass lenses, etc., and a target plate used therefor.

Refractive properties of optic lenses for eye refractive correction IE such as eyeglass lenses and contact lenses (hereinafter simply referred to as test lenses);
For example, a lens meter is well known as an optical device for measuring spherical refractive power, cylindrical refractive power, and its axial angle, as well as prism refractive power and its direction.

Examples of conventional measurement targets for z/zmeters include a corona target in which small circles are arranged in an annular shape, a canicross line target in which two sets of Wright's patterns consisting of two lines and three lines are orthogonally crossed. It is being In the 4111 constant horn method in the cylindrical axis direction of the astigmatic lens to be tested in a lens meter with these conventional targets,
The resonance of a corona target is measured with the flow direction of the corona small circle as the cylinder axis direction, and in the case of a cross line target, the line pattern runs at the position where the distortion of the small rectangle group at the line pattern intersection has been corrected. The direction was measured L=1- with the cylinder axis direction.

However, in these conventional lens meters, the astigmatic lens to be tested has a cylindrical refractive power of, for example, 0. / 2
In the case of a mildly astigmatic lens with only a minute amount of 0.2 J dioptor, the flow rate of the above-mentioned corob target, cross line kugeso i
Since the distortion of the small rectangular group is minute, it is difficult to determine the cylinder axis direction, and therefore, there is a drawback that it is not possible to accurately determine the refractive characteristics of the lens to be tested.

Another example of the conventional lens meter 4111 Sadakawa Kugeso l- is a right angle /, a small circle in the c1″λ direction, and a small circle in the direction of c1″λ. No. 1 and the United Kingdom are also 11j' ``1./417.
A small circular image flowing in the direction of the cylindrical axis of the lens]・r7.
This is to take advantage of the fact that it is easy to detect because it overlaps with other small circular images. However, even with this configuration, the minimum cylindrical power of commercially available eyeglass lenses C=0. /2! It is difficult to make measurements on the order of diopters quickly and accurately.

It is an object of the present invention to provide a lens meter that can improve measurement accuracy, particularly the direction of the cylinder axis of a 1/lens to be tested having a weak cylinder refractive power, with greater accuracy than conventional lens meters.

No. of the claimed invention! The purpose of this was to resolve the shortcomings of conventional target plates for lens meters, and compared with conventional target plates for lens meters [7] the measurement accuracy, especially the weak cylindrical refractive power, was improved. An object of the present invention is to provide a target plate for a lens meter having a new target pattern that allows the direction of the cylindrical axis of a lens to be measured with higher precision.

The feature of the present invention for achieving the second object is that an intention line group pattern consisting of at least two parallel dotted lines is used as the target pattern of the target board, and the dotted lines constituting the point back-7 . The diameters of each of the dotted lines and the distance between the dotted lines should be constructed so that they have a quantitative relationship as will be detailed later. 71+++ +6 +6 for the measurement of the minimum measurable cylindrical power of the test lens required for the test lens and the test astigmatism lens of the test lens having a cylinder power higher than that, and the arrangement of the black surface line group pattern is in the direction of the cylinder axis force of the test astigmatism lens. Only when they match, dot patterns corresponding to the lives of adjacent black blood lines come into contact, forming a black blood line correction pattern. The dot pattern coincides with the cylindrical direction of the astigmatism/s to be tested, and acts so that the dot pattern shifts and becomes a non-contact state when cutting.

The advantage of the present invention is that the visual characteristics of the examiner's human eye, that is, the visual characteristics of the human eye of the examiner, such as a curved straight line or a group of straight lines with respect to a certain reference line or reference direction, are complicated. Compare the ability to perceive whether or not
Phase 1 is adjacent. This is because the human eye's visual ability, which has a superior ability to perceive whether two straight lines or two groups of straight lines 7tY match or do not match, is utilized.As a result, If an astigmatic lens to be tested is measured using the lens meter and lens meter target plate provided by the present invention, it will have a weak cylindrical refraction /J.
Even in a test astigmatic lens, it is possible to accurately measure seven points in one direction by 1 F.

The configuration, operation, and effects of the present invention will become clearer through the following detailed explanation of principles and embodiments based on the drawings.

First, the present invention will be explained in detail. FIG. 1 is a perspective view showing the principle of the configuration of an optical system of a lensmeter. first,
The configuration and operation of this optical system when the test lens TL is not placed in a fixed optical path will be explained. When the test lens T is not placed in the optical path, the emitted flux of a point target t on the target plate T placed at the front focal position of the collimator lens CL having a focal length f+ is:
After exiting the collimator lens CL, the collimator lens CL is directed toward the objective lens OL. This objective lens 0 has a focal point +Fi+- located at the rear focal point f2. - The parallel light beam from the collimator lens that enters the objective lens OL forms an image t' of Kugela) 1 on the focus plate by the objective lens OL. Here, the light flux used to form the target image t' is mainly determined by the effective diameter φ of the test lens receiving section S for placing the test lens in the measurement path C.

Next, the test lens 11, which is an astigmatic lens.
47 The lens receiver is placed in the measurement optical path by the part S.Consider the state in which the lens receiver is placed in the measurement optical path g.After the test lens T1- is emitted, the image G'! -The image is formed on the focus plate and becomes blurred. Therefore, the target plate T is il]l
The focusing plate must be moved back and forth using the fixing bar and the lever, and the focus adjusted so that the target image t' is focused on the lens.Jt 4
No work) / n. However, in this case, since the test lens TL is an astigmatic lens, the target fl t'
The target t is point-like, and the force f is also: Jno et al. 14
The test lens is not imaged as a point f image, and the test lens is 0 strong/weak °C・-f
Direction 1 perpendicular to the main meridian direction of 9.
i21 line'') becomes a ζf elephant. -111-wnri+n
immwwwwww - The length of this focal line is 2h and 12 as shown in FIG. [ifl, constant nine' system of the lens meter and the test lens is a thin lens system - C Consideration - J - Stone and 1. C.

The amount of movement of the target plate T is 4J
There is a linear relationship with the i force, and the unit Ji! (41i horn j fishing) Movement amount m of target plate ■. , and 1. Cru. Here, fl is the focal length of the collimator lens CL as described above. Therefore, the lens to be tested TL
Assuming that the cylindrical refractive power of is C diopters, the movement width m of the target plate (2) is 10θ0.

That is, in FIG. 1, from the state where the first focal line F1 is focused on the focus plate, the target plate T is
) When the movement width of the equation (2) is moved, the first focal line [1 on the focusing plate moves and the second focal line F2 is focused on the focusing plate instead.

Next, consider the magnification relationship of the target image (focal line image). As mentioned above, when the lens to be tested is placed in the defined optical path, the lens meter moves the target plate (■) in the direction of the measurement round axis to convert the light beam that exits the lens to be measured into a parallel light beam, and The light beam is focused on a focus plate placed at the focal point of the objective lens, and a target image can be formed.

The refractive power of the lens to be tested is determined from this state, that is, the position after the target plate T has been moved.

Combined focal length f when two lenses with focal lengths N+ft t + and fl are placed on Mlu with an interval t
L1 is /// --- ten --□ ・・ ・(3
) fo fl fjflfJ. Therefore, a collimator lens CL with a focal length f1 and a test lens TL with a focal length F (if the test lens is an astigmatic lens, the focal length of the first and second principal meridians) are fl. The combined focal length Fq of the lens TL and the collimator lens C1jDllll is basically the same as the above equation (3) where the test lens TL is placed apart from the collimator lens CL by the focal length f of the collimator lens CL. In other words, the focal length is always the focal length f of the collimator lens. On the other hand, since the test lens TL and the objective lens OL are parallel light beams with a G negative t, the lateral magnification β of the entire optical system is 2 β knee ... (J) f.

The focal line distance DF between the focal line F2 is DF = P
It can be determined by f 2 12 =□・C・β2 000 000. From this, the length of the focal line h(
, -The length h of the focal line is the length of the high point 111 bordering the optical axis (.).The length of the entire focal line can be expressed as 2h.

) follows from the proportional relationship. From equation (7), the length tlH of the focal line on the focusing plate T
To calculate, h7 = − β −・−= (f) f2 ・C11000 2 and/, (Here, let the cylindrical power be C, and the minimum measurable cylindrical power required for this lens meter is The minimum cylindrical power of commercially available eyeglass lenses is C-0, / , 2 J
In diopters, the length hT of the target plate T1-C- is given by the rod equation.

As shown in FIG. 2 (A), point baton 1 on the target board T. ．． If the distance between the centers of 12 is chosen so that they match at the minimum cylindricity C, then k=
= 21 pieces... (According to 1. Map, 2, point pattern ↑ 4. The diameter a of each λ't of t2 is a ``'' so that k - D = hH.
tll...,...(//)
I choose. The minimum measurable cylinder power G of this lens meter
, (in equation (R), C = 0./noj), the first
cylindrical axis direction and target] When the arrangement directions of points t and t on the tide T are orthogonal, if you replace it, it is 1, and the 1st of the tested lens! The cylindrical axis direction of The image t, /dot2/ is the 20th cylindrical refractive power of the attrition lens, and the image flows in the direction of the second circle A:1-1.
The λ point pattern images t, L and t2' should be such that their ends touch each other by 1 in 5 degrees.

Depending on whether the point pattern images t,' and t2' are in contact with each other, in other words, whether their ends coincide with each other, the point patterns t1 and 12 of the target board T are determined.
It is possible to detect whether or not the arrangement direction of the lens and the cylindrical axis direction of the lens to be tested match.

As described above, the present invention makes full use of the coincidence and non-coincidence of the ends of the λ straight line, which is extremely sensitive in terms of the human eye's rj~sensibility and perceptual accuracy, so that the measurement accuracy in the cylinder axis direction can be improved. It has the advantage of being able to make it very high.

Hereinafter, specific embodiments of a lens meter and a target plate for a lens meter based on the principle described above will be described in detail with reference to the drawings. First, a first embodiment of handling a lens meter target will be explained based on FIGS. 3 to 6. FIG. 3 shows a first embodiment of the target plate of the present invention in the horizontal direction 1r/l. The target board 1 has a large number of dotted turns 21a + 22a, 23a and 2na.
A first point straight line 2a consisting of a plurality of point putters 721 b , 22 b , which are arranged parallel to the first point straight line 2 a .
23 b ・= 2nb or 1 second point straight line 7b is formed, and these first point straight line 2a and first point point 1
Dot-dotted line group pattern 2 is constructed from 1iJ312b. In addition, the target' plate 1 has the dot line group pattern i
Direct so that it is orthogonal to! Pattern 3 is formed.

As will be described later, this straight line pattern 3 is for making it easier to read the first focal line direction measured by the point line group pattern, that is, the second cylinder axis direction that is orthogonal to the first cylinder axis direction. , is not an essential component of the invention.

Figures 1t to 6 are for explaining the operation when measuring an astigmatic lens to be tested using the target plate shown in Figure 3, and show the relationship between the target plate and the lens to be tested. Shown schematically. In Fig. 3, the target plate 1 moves the point line group pattern 2 in the direction 4, as in Fig. 3.
The linear pattern 3 is placed in the direction 5, and the first cylindrical axis 6 is placed in the constant optical path Q.
The direction of l is V, and the λth cylinder side 17 is Q2 = Q+ 470
For other measurements, consider the case where the test lenses 8 are placed in the direction of .degree. (2). the law of nature,
Focus on the first cylinder axis with 1. At this time, the target observation image obtained by the moxibustion person is as shown in FIG. That is, the point pattern image 21 a' + 22 a' + constituting the black blood line group] 9-turn image 2'
23 a'2na' and point pattern ri 21 b'
, 22 b', 23 b'...2nb' are respectively in the direction of the axis j5 direction Q1 of the first cylindrical shaft 6,
The t-line (observed as an elephant 7). Then, the arrangement direction 4 of the group of dotted lines and the turn i on the target plate 1- coincides with the direction of the first cylinder l1Ill16 of the test lens 8. Therefore, the point pattern images (21a', 21b'), (22
a', 22b'), (23a', 23 b')
・-(2·n, a', 2n b') are observed by VC so that they have the first quantity of Δ with respect to their opposite ends.

In addition, since the linear pattern image 3' also coincides with the cylindrical axis of the tested lens, the wide Q-moon I is 7. (reactor.

Next, the target plate 1 is rotated, and as shown in FIG. 5, a dot pattern image 21 a' + 22 a' + 23
a'=・2 n a' and point pattern image 2 lb', 2
2b', 23b'... 2nb', match each end a). , 2, the running direction of the linear pattern image 3' coincides with the running direction of the dot pattern image, and for the above-mentioned reason, the running direction of the linear pattern image 3' is aligned with the first cylindrical axis 6. of the lens to be tested. Therefore, the first cylinder axis direction Q1 can be read using the angle scale plate 9 on the focusing plate.

To read the direction of the first cylindrical axis 62 of the lens to be tested, the target plate 1 is simply moved on the constant optical axis without rotating it. At this time, as shown in FIG. 6, one black blood line 2 a , −
The dot pattern 2b matches other dot pattern images of the same black blood line. The state where the focus is focused on the second cylindrical axis of the lens to be tested is the state where the lens is focused on the second cylindrical axis of the test lens, and the angle scale 9 of the focusing plate T is set using the line of intention image 7 a' + 2 b'. Therefore, its axial direction Q2 can be read. At this time, the straight line pattern image 3' is the second cylinder l.
111 Because it flows in the direction Q2, it becomes blurred (elephant) in that direction.

FIG. 7 is a plan view showing a second embodiment of the lens meter for lens meter according to the present invention. This tag l-
On the board 10, there is a first dotted line group Baku 712 consisting of one black blood gland 11a, 11b 7'J-, and two other dotted plane lines 1.
3a and 13b are formed so that the λ-th black blood line group bata -714 are orthogonal to each other. Also, the first point straight line group pattern 12 and the second straight line! The intersection with the iY pattern 14 is cut JL, and at this intersection a conventionally known circular corona pacoon or a hole (inside) is formed so as to coincide with the measurement optical axis. The cylindrical axis direction of the test lens that has a circular corona pattern in medium heat and has a strong internal power is the direction of the flow of the point putter 7 that constitutes this circular corona. This is so that you can get it.

In addition, in the above-mentioned first and second embodiments KJ, a specific numerical example of the diameter a of the point pakun and the interval of the black blood line 2a + 2b is expressed by formula (9) or //). The result is as shown in Table 1.

Fig. g shows an optical system layout (rows are shown) showing an example of the configuration of a lens meter having the target plate described in -.

On the measurement photometer 10, there are a target plate 1 and a target plate 1.
a light source 20 for illuminating, a collimator lens 21,
The test lens holder includes a means 22, an objective lens 23, and a focusing plate 24.
, and each have an eyepiece lens 25. The target plate 1 is attached to the cylinder 4IIJI33 (T') 11-1 cylinder +1Ill+ 33 is rotatably fitted into a bearing member 32 having a rack 31 that moves back and forth as the pinion 30 rotates. In addition, the rotation...-'1 lever 34 is
A IIl11 tube 35 is fitted into the cylindrical shaft 33. ,
The inner surface of the second shaft tube 35 has slots J6 and 3 in the Tsukuda 1 direction.
6 are formed, and pins 37 and 38 implanted in the cylindrical shaft 32 are inserted into the slots 35 and 36, respectively. With this configuration, the rotating wheel 34 is rotated 1. The target plate 1 can be rotated around the optical axis 0, and the target plate 1 can be moved back and forth in the direction of the round axis O by rotating the pinion 30 IM+.

The shift AI+ difference between the targets 4 and 1 can be read as a door iopter value from the scale plate 40 attached to the rack 31. A scale image 40' of this scale plate 40 is projected onto the focus plate 24 by a scale relay optical system 414C.

Although the embodiments of the lens meter described above relate to a so-called telescopic lens meter, the present invention is limited to this.1. It goes without saying that c< does not hold true even in a so-called projection type lens meter having a configuration in which the focus plate 24 is a screen.

[Brief explanation of the drawing]

Fig. 1 is a YC layout diagram of a lens meter for explaining the present invention in detail, Fig. 2 is a diagram showing the relationship between point butterflies, and Fig. 3 is a first embodiment of the target plate of the present invention. FIG. 6 is a plan view showing an example of the target plate of the present invention, FIG. 1 and 2 are explanatory diagrams showing an embodiment of the lens meter of the present invention. Focus plate patent applicant: Tokyo Kogaku Kikai Co., Ltd., Figure 4, Figure 5

Claims (1)

[Claims] /) Rotatable with the measurement optical axis as the rotation axis 1. c A target plate, a light source for illuminating the target plate, a collimator lens having a focal point at the position of the target plate, and a collimated light beam from one of the collimator lenses is focused onto the focusing plate to illuminate the target plate. A lensmeter comprising: an objective lens for forming an image on the focusing plate; and a means for placing a test lens placed between the collimator lens and the objective lens. In , the target plate has a black surface line group pattern of at least two movable points (σ rays or I:, 7), and the focal length of the collimator lens is f. (mm). The focal length of the objective lens is 12 (mm),
Use effective luminous flux diameter φ, "pM J<S, 11" The minimum measurement cylinder 1w number of the test lens is C (teopter): H7C
When each point is off, the diameter of each of the point patterns constituting the ri line is hT, and the interval between the two adjacent dotted lines is 2h. A lens meter featuring: 2. The lensmeter according to claim 1, wherein the target plate has two black surface line group patterns formed so as to be perpendicular to each other. 3) The intersection of the one black blood line group and the pattern is cut, and the cut part has a circular corona pattern. Lensmeter according to item 2. A light source for illuminating a target plate that is rotatable about the measurement optical axis and the light beam of the target plate is parallel to the target plate.)
Focal length f to form a 'r7 bundle. (mm) collimator lens and effective luminous flux diameter φ (
The lens holder to be tested (mm) focuses the light beam from the collimator lens onto the focusing plate, and
The focal length f2 (
This is a target plate for a V-lensmeter that has an objective lens of M+J), and the target doctor has a regular (both two parallel dotted straight lines or) l wobbling intention line group pattern. , when the required minimum measured cylindrical power of the lens to be tested is C (diopters), the diameter of each point pattern forming the nil notation straight line is given as: The distance between the two adjacent dotted straight lines is 2+1T.
A target plate for a fish/Zuno-ku, characterized by having an amount of 7. j) The above-mentioned intention line group pattern is like 2 straight fathers (・t samurai whose 4 temple sign is ko shape 1 戊 λt)
] 11 Aogu range No. 1/- around 1/- period lens noter toy cloth. The lens according to claim 5, wherein the intersection of the λ intention line group patterns shown in o r=+fl is cut, and the cut part has a circular corona pattern. Target for meter) board.