JPH0726675Y2 - Lens meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a digital lens meter.

[Prior Art and its Problems] Recently, various auto lens meters have been proposed which automatically measure optical characteristics of lenses. However, digital lens meters have become widespread due to problems such as price.

Regarding the digital lens meter, for example, Japanese Patent Laid-Open No. 54-
A projection type digital lens meter is proposed in Japanese Patent No. 51545.

The basic technique itself, whether it is a telescopic type or a projection type, is known and can be evaluated as the same, so that the projection type digital lens meter will be described.

In a general projection type digital lens meter, when the lens to be inspected is inserted into the measurement optical system, long and short axis-shaped target images that are orthogonal to each other are blurred, but until the target image is focused on the target so as to eliminate the blurring. It is moved, and the amount of movement is read by a potentiometer or the like and converted into the refractive power of the lens to be inspected.

By the way, unlike a spherical lens, an astigmatic lens has two focus positions of a target image, and therefore the optical characteristics of the lens to be inspected cannot be obtained unless the power at each focus position is measured.

As described above, the astigmatic lens has the strong main line and the weak main line, but the strong main line and the weak main line can be distinguished only by measuring the refractive powers of the two main meridians.

This is for the purpose of merely obtaining the refractive power of the lens to be inspected, but it causes a problem when the lens is axially aligned so as to coincide with the astigmatic axis of the eye to be inspected before the lens processing.

Generally, the axis is rotated by rotating the target rotation ring to align the long axis of the target with the desired direction (prescription value), then move the target in the direction of the optical axis so that the long axis of the target is in focus, and then further axially. With the lens rotated,
Do this. However, since there are a plurality of methods of expressing the same astigmatic lens, this type of device is usually provided with a mode switching switch for plus reading and minus reading.

The following relationship exists between the negative reading (S, C, AX) and the positive reading (S ', C', AX '), which is the method of expressing the astigmatic lens.

S '= S-C C = -C' AX '= AX + 90 ° (However, when AX + 90 ° exceeds 180 °, AX' = AX-9
0 °) As described above, the astigmatic axis causes a 90 ° shift in the astigmatic axis.

As described above, the strong main line and the weak main line can be distinguished only by obtaining the refractive powers of both main meridians, so many existing devices use the first measured meridian line to measure the refractive power of the astigmatic lens. Is calculated (whether the calculation frequency is negative reading or positive reading is not constant), and then automatically converted according to the designated expression mode.

If you do not notice that this conversion has been done, if you axially strike at the axial angle indicated by the target, you will result in the axial offset at a position shifted by 90 °.

Such a situation occurs with a probability of 1/2 regardless of the specific procedure of automatic conversion.

As described above, in the conventional device, special knowledge is required to correctly set the shaft.

[Object of the Invention] The present invention has been made in view of the above problems of the conventional device, and an object thereof is to provide a digital lens meter which can be axially driven without error even without special knowledge.

[Configuration of the Invention] In order to achieve the above object, the present invention has a projection optical system that projects a measurement target onto a predetermined observation surface, and the eyeglasses to be inspected are based on the amount of movement of the measurement target detected by the detection means. In the lens meter that calculates the refraction characteristics of the lens and displays the calculation result on the display, set the astigmatism expression method when the spectacle lens to be inspected is an astigmatism lens and set the set astigmatism expression method to another astigmatism expression. A mode switching means for switching to a method, a computing means for computing the refractive power and the astigmatic axis angle according to the astigmatic expression method selected by the mode switching means, and an astigmatic axis direction indicated by the measurement target projected on the observation surface. A determination unit that determines whether or not the astigmatic axis angles obtained by the calculation unit match, and a notification that notifies the examiner of the determination result by the determination unit And means.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electric system of the embodiment of the present invention.

Reference numeral 1 is a power measuring potentiometer, which detects the amount of rotation of a diopter handle (not shown) for moving the target with the potentiometer. Reference numeral 2 is an amplifier that amplifies the signal of the potentiometer 1. Reference numeral 3 is a potentiometer for axis measurement, which detects the amount of rotation of a rotating ring (not shown) that rotates the target about the optical axis. An amplifier 4 amplifies the signal of the potentiometer 3. 5 is an amplifier
It is an A / D converter that converts analog signals 2 and 4 into digital signals.

Reference numeral 6 is a microcomputer for controlling the entire apparatus.

Numerals 7 and 8 are indicators showing a measurement procedure, and indicate whether to measure the short axis direction or the long axis direction of the orthogonally projected image of the target. Since the apparatus of this embodiment does not have a detecting means for determining whether the inspector focuses the long-axis target image or the short-axis target image, the measurement order is set in advance. This distinguishes the two.

In the present specification, the long-axis target refers to a target image whose axial angle can be matched, and the short-axis target refers to a target image in a direction orthogonal to this.
It has no further meaning.

Reference numeral 9 is a display driver, and reference numerals 10, 11 and 12 are display units for displaying the measurement results, which display the spherical power, the astigmatic power, and the axis angle, respectively.

13 is a printer driver, and 14 is a printer for printing the measurement results.

Reference numeral 15 is a CYL +/- switch for changing the reading mode of the astigmatic lens from one mode to another reading mode. Based on the signals of the CYL +/- switch 15 and the CYL mode selection switch 18 described later. The microcomputer obtains the measured value according to the designated reading mode.

The S / C switch 16 switches SPH / CYL measurement mode.

Reference numeral 17 is a print switch, and 18 is a CYL mode selection switch for setting the display mode of the astigmatic lens. Reference numeral 19 is a measurement step selection switch for switching the measurement result display step.

Incidentally, 18 and 19 are dip steps.

The operation of the above embodiment will be described with reference to the flowchart of FIG.

Place the lens to be inspected in place. At this time, the device is set to the SPH measurement mode (step 100), and the short axis indicator 7 lights up (step 101). The target is moved by operating the diopter handle (not shown) so that a corona image (not shown) of the target can be clearly seen on the screen. If the corona does not flow, finely operate the diopter handle (not shown) while looking at the short axis target to adjust the focus (step 102). The rotation amount of the diopter handle, which is proportional to the target movement amount, is detected by the power measuring potentiometer 1, amplified by the amplifier 2, and
After being converted into a digital signal by the D converter 5, it is input to the microcomputer 6.

The microcomputer 6 processes the signal, converts it into a diopter value (step 103), and displays it on the spherical power display unit 10 via the display driver 9 (step 10).
Four).

At this time, if the lens to be inspected is a spherical lens, the long-axis target does not come into focus and the corona does not flow, so the optical center is immediately marked.

In the case of an astigmatic lens, while observing the corona flow, turn the target rotation ring to make the short-axis target image parallel to the corona flow, operate the diopter handle (not shown), focus and obtain the SPH value. .

Next, the S / C switch 16 is pressed (step 105) to switch to the CYL measurement mode (step 106). Then, the long axis indicator 8 is turned on (step 107).

Turn the diopter handle as in SPH mode,
The long-axis target image is focused to obtain the refractive power in the long-axis direction (steps 108 and 109).

The astigmatic power is obtained by subtracting the refractive power in the short axis direction from the refractive power in the long axis direction (step 110), and the astigmatic axis angle is obtained from the axial angle in the long axis direction (step 111), and displayed (step 112). ).

It is determined whether the measured value thus obtained matches the mode designated by the switch for selecting the representation of the astigmatic lens (step 113).

When they coincide with each other, the long-axis indicator is continuously lit (step 114), so that the process advances to the axis-setting step. After turning the target rotation ring to align the long axis of the target with the direction (prescription value) you want to hit, move the target in the optical axis direction so that the long axis of the target is in focus, and then rotate the lens. , Make a shaft.

If the measured value does not match the mode designated by the switch for selecting the representation of the astigmatic lens, it is automatically converted into the measured value according to the mode (step 115) and displayed. .

Here, when the direction indicated by the long-axis target image and the direction of the calculated astigmatic axis angle are different, the microcomputer 6 blinks the long-axis indicator 8 (step 11).
6). In this case, the lens is rotated 90 °, the S / C switch 16 is pressed, the measurement is performed again, and then the lens is axially hit.

Note that the warning means may take various forms including a warning by voice other than this embodiment.

[Advantages of Device] As described above, according to the present invention, by issuing a warning in advance for an error that an inspector is likely to make when axially driving, it is possible to avoid axially driving at an incorrect angle.

Further, it is possible to handle even a person who does not have special knowledge about the astigmatism mode.

[Brief description of drawings]

FIG. 1 is a block diagram of an electric system of an embodiment of the present invention, and FIG. 2 is a flow chart of its operation. 1 …… Power measurement potentiometer 3 …… Axis measurement potentiometer 8 …… Long axis indicator 19 …… CYL mode selection switch

Continuation of the front page (56) Reference JP-A-53-69058 (JP, A) JP-A-57-80537 (JP, A) JP-A-55-46166 (JP, A) Actual development Shou-55-53440 (JP , U)

Claims (2)

[Scope of utility model registration request] 1. A projection optical system for projecting a measurement target onto a predetermined observation surface, and calculates the refraction characteristics of an eyeglass lens under test based on the amount of movement of the measurement target detected by the detection means, and the calculation result. In a lens meter for displaying on a display, a mode switching means for setting an astigmatism expression method when the eyeglass lens under test is an astigmatism lens and switching the set astigmatism expression method to another astigmatism expression method, and the mode switching Calculating means for calculating the refractive power and the astigmatic axis angle according to the astigmatic expression method selected by the means, and the astigmatic axis direction indicated by the measurement target projected on the observation surface and the astigmatic axis angle obtained by the calculating means. It is characterized by further comprising: a determination unit that determines whether or not they match, and a notification unit that notifies an examiner of a determination result by the determination unit. Nzumeta. 2. A lens meter, wherein the notifying means of claim 1 is means for blinking an indicator showing a measuring procedure.