JP2002082017A - Lens meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens meter capable of highly reliably measuring an addition power even of a progressive-power lens applied with a special machining called a prism thinning machining. SOLUTION: This lens meter for measuring an optical characteristic of an inspected lens comprises a measurement control means for continuously measuring refractivity at a predetermined interval, a display for displaying a graphic diagram having a region simulated in a progressive band in order to guide a measurement point in a progressive-power lens measuring mode set by a mode switching means for switching a mode to the progressive-power lens measuring mode, a guiding means for displaying on the display a target indicating the present measurement point for a marker based on a measurement result obtained under the control by the measurement control means, a storing means for storing a measurement result when the measurement point lies in a remote region, and a monitoring means for monitoring whether the measurement point displaces left or right from the progressive band based on the measurement result of the remote region and the present measurement result in order to move the measurement point to a closed part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens meter for measuring optical characteristics of a lens, and more particularly to a lens meter suitable for measuring an addition.

[0002]

2. Description of the Related Art A measuring lens is projected onto a lens to be measured, and the trajectory of the measuring light transmitted through the lens to be detected is detected by a light receiving element. -Is known. This lens
The camera usually has an addition measurement mode, and measures the addition of a progressive multifocal lens or the like.

According to this apparatus, after measuring and storing the distance portion of the lens to be inspected, the mode is switched to the addition measurement mode, the lens is moved from the measurement position, and the examiner reaches the near portion. The measured value at the position determined to be is stored, and the addition is calculated and displayed from the difference.

[0004]

However, in the apparatus described above, the positions of the distance portion and the near portion are left to the subjective judgment of the measurer, and the accuracy of the judgment is determined by the measurer. It depended on intuition and experience. Usually, a mark is attached to each position of the distance portion and the near portion of the lens before the framing, so that accurate measurement can be performed according to the mark, but the mark is easily erased. . Further, these marks are wiped off by the lens after the frame is placed, making it difficult to visually recognize the hidden marks. Therefore, there is a problem that a measurer needs considerable skill for accurate measurement, and there is no objective material for ensuring the accuracy.

A first object of the present invention has been devised in view of the above-mentioned drawbacks, and enables a highly reliable addition measurement even with a progressive lens which has been subjected to a special processing called prism thinning. It is to provide a lens meter which can be used.

A second object of the present invention is to provide a lens meter capable of measuring the addition without depending on the skill of the measurer.

[0007]

The present invention has the following features to achieve the above object.

(1) A lens lens for projecting measurement light onto a lens to be measured, detecting the trajectory of the measurement light transmitted through the lens to be measured by a light receiving element, and measuring the optical characteristics of the lens based on the detection result. A mode switching means for switching to a progressive lens measurement mode, a measurement control means for continuously measuring the refractive power at predetermined intervals, and a progressive lens measurement mode by means of the mode switching means. At the time, a display that displays a graphic figure having an area simulating a progressive zone to guide a measurement point, and a position where the amount of prism in the left-right direction becomes almost 0 when the test lens is assumed to be a spherical lens A marker indicating a current measurement point for the marker based on the measurement result measured by the control of the measurement control means is displayed on the display. Guidance means for displaying, storage means for storing a measurement result when the measurement point is in the distance portion area, and a measurement result of the distance portion area and the current value for moving the measurement point toward the near portion. Monitoring means for monitoring whether the measuring point has deviated to the left or to the right of the corridor based on the measurement result,
Is provided.

[0009]

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Configuration] (External Configuration Diagram) FIG. 1 is an external view of a lens meter according to the present embodiment.

Reference numeral 1 denotes a display, which is a normal measurement mode.
In the display, a reticle indicating the optical axis of the measurement optical system, a cross target for positioning, a measurement result, and the like are displayed. FIG. 1 shows a display in the additional power measurement mode, which will be described later in detail. 2 is a print switch for printing the measurement results,
Reference numeral 3 denotes left and right selection switches, and 4 denotes a switch for reading a measured value. Reference numeral 5 denotes a progressive lens measurement switch for switching the measurement mode for progressive lens measurement.

Reference numeral 6 denotes a lens holder, on which a lens L to be measured is mounted on a nosepiece 7;
And hold the lens L to be tested. Reference numeral 8 denotes a backing plate, which moves toward the front in the figure by pressing the frame.

(Refractive Power Measuring System) Next, an example of a measuring optical system for a lens meter will be described with reference to the optical system layout diagram of FIG.

Reference numeral 11 denotes a light emitting diode such as an LED.
Four are arranged near the focal point of the objective lens 12 orthogonally to the optical axis. When the lens L to be inspected is set on the nosepiece 7, an LED is issued according to an instruction from the microcomputer.
The driver operates and the four LEDs (a, b, c, d) are sequentially turned on. The sequential lighting of the LEDs a to d is performed while the lens L having refractive power is placed on the nosepiece 7.
It is performed repeatedly at predetermined time intervals.

Reference numeral 13 denotes a measurement target plate having orthogonal slits, which is fixedly disposed near the focal points of the objective lens 12 and the collimating lens 14. If the lens L to be inspected has a power (refracting power) other than 0D, the four target images are blurred and the image positions are shifted by an amount proportional to the power, causing a measurement error. For the measurement, it is desirable to move the target plate so as to reduce the amount of displacement.

The nosepiece 7 is arranged near the focal point of the collimating lens 14 and the imaging lens 15.
Reference numeral 16 denotes a half prism, and 17 denotes two one-dimensional image sensors which are provided so as to be orthogonal to the optical axis and arranged so that their detection directions are orthogonal to each other.

The light from the LED 11 forms an image on two orthogonal image sensors 17 via the objective lens 12, the collimating lens 14, the lens L to be inspected, and the imaging lens 15, respectively.

The relationship between the refractive power of the lens to be measured and the imaging position of the measurement target will be briefly described. The target 13 is individually illuminated by four LEDs. However, when there is no lens to be inspected and when a 0D lens is mounted on the nosepiece 7, the LEDs a, b, and For c and d, the target images formed on the image sensor 17 respectively overlap each other.

When the test lens L has only a spherical refractive power, the position of the target image formed on the image sensor 17 moves on the image sensor 17 by an amount corresponding to the spherical refractive power. .

When the test lens L has only a cylindrical refractive power, a light beam incident on the cylindrical lens has a refractive power in a direction (or the same direction) orthogonal to the main diameter line. The columnar refractive power can be calculated from the amount of movement of the target image.

Now, the center of the target image when each of the LEDs a, b, c and d is turned on is A (xa, ya).
), B (xb, yb), C (xc, yc), D (xd, yd)
)age,

[0021]

(Equation 1)

[0022]

(Equation 2)

[0023]

(Equation 3)

[0024]

(Equation 4) After all,

[0025]

(Equation 5)

[0026]

(Equation 6)

[0027]

(Equation 7)

[0028]

(Equation 8) Becomes

The microcomputer 25 described later substitutes the center coordinates of the target image of each LED into the above-mentioned formula to calculate the spherical refraction, the column refraction, the axis angle, and the prism amount. -When the get plate is moved, it is corrected by the amount of movement.)

(Control Circuit) FIG. 3 is a block diagram showing a main control circuit of the present apparatus.

The signals of the two image sensors 17 are CCD
Through a driving circuit 21, a comparator 22 and a peak hole
Is input to the threshold circuit 23. The peak voltage input to and detected by the peak hold circuit 23 is converted into a digital signal by the A / D converter 24, and then input to the microcomputer 25. The digital signal of the peak voltage output from the peak hold circuit 23 is supplied to the computer 25.
The signal is converted into a voltage signal of a half of the peak voltage by the D / A converter 26 and input to the comparator 22. This signal is compared with the signal directly input to the comparator 22 to generate a strobe signal. The signal of the counter 27 enters the latch 28 in response to the strobe signal.
The coordinate position is detected by the data 25, and the optical characteristics of the lens to be measured are calculated based on the detection result.

These information are stored in the microcomputer 2
5 via the display control circuit 29,
Characters and graphics are displayed on the display 1 together with the storage information of the apparatus. [Operation] The operation of the lens meter configured as described above will be described.

First, the measurement mode of the single focus lens will be briefly described. Spherical power, astigmatic power of a single focus lens,
In the mode for measuring the astigmatic axis angle, the display 1 displays a reticle centered on a point indicating the measurement optical axis. The sequential lighting of the LEDs a to d is repeatedly performed at predetermined time intervals, and the refractive power is continuously measured. When the test lens L is placed on the nosepiece 7, the refractive power of the test lens L is calculated and displayed on the display 1, and the optical axis of the test lens L and the measuring light are measured from the prism value. Obtain the amount of displacement from the lens to be measured on the axis (Prentice's equation). The display control circuit 29 superimposes the cross target on the reticle of the display 1 and displays the cross target at a position corresponding to the shift amount. When the reticle and the cross target have a predetermined positional relationship, the measured value is the measured value of the lens to be inspected.

Next, the measurement mode of the framed progressive multifocal lens will be described. The progressive lens measuring switch 5 is pressed to set the progressive multifocal lens measurement mode. In a state where the test lens is not mounted, the screen of the display 1 includes two curves 30 simulating a progressive portion (band) fixedly displayed and a measurement point as shown in FIG. The vertically long rectangular target 31 shown is displayed. Press the left / right selection switch 3 to specify the left and right sides of the lens to be measured, and the lower side of the frame (in this specification, the upper and lower sides of the frame and the lens mean the upper and lower sides with the spectacles on). Is brought into contact with the frame holder 8, and the lens to be inspected is
It is placed on the speed 7 (contact with the frame holder 8 enables stable movement). The lens to be inspected is placed on the nosepiece 7 slightly above the center from the center, and the step of measuring the distance portion is started.

The marker 32 flashes slightly below the center of the display 1. The marker 32 indicates the target of movement of the target 31, and the position of the target 31 with respect to the marker 32 informs the measurer of the direction (and the amount of movement) of the lens to be moved. The distance portion of the progressive multifocal lens exists on an axis (hereinafter, referred to as a distance portion axis in the present specification) where the prism in the left-right direction of the test lens in the case of a spherical lens is 0. Accordingly, the initial marker 32 indicates the position on the axis of the distance portion (FIG. 4B).

If the lens to be inspected is a spherical lens, the direction and amount of deviation from the axis of the distance portion can be obtained based on the prism values in the left and right directions at each measurement point. It is displayed at a position indicating the relative position of each measurement point with respect to the power 32.

When the test lens is an astigmatism lens, the position where the prism becomes 0 in the left-right direction of the test lens is on the astigmatism axis. Therefore, the influence of the astigmatism lens is offset from the prism value at each measurement point. Then, correction is made to values indicating the amount of deviation and the direction of deviation from the distance portion axis (the spherical lens may be considered as a special astigmatic lens with C = 0).

Now, in any astigmatic lens having each value of S, C, and A, an arbitrary point A (in which the optical center of the lens is set to 0 and the axis of the distance portion is set to the Y axis) in the XY coordinates. x, y)
The prism amount (Px, Py) at is: Px = − (Dxx · x + Dxy · y) Py = − (Dyx · x + Dyy · y) The prism amount (Px0, Py0) at point B (0, y) is Px0 = − Dxy · y Py0 = −Dyy · y where Dxx = S + Csin 2θ Dyx = −Csin θ · cos θ (= Dxy) Dyy = S + Ccos 2θ C is a minus reading. From the above equation, Px0 = Dxy · (Py · Dxx−P
Since x.Dyx) / (Dxx.Dyy-Dyx.Dxy) is obtained, the position of x = 0 and the display position of the target are determined by offsetting Px0 from Px. This offset calculation is performed thereafter, and its position is monitored.

The measurer moves the lens to be inspected to align the target 31 with the marker 32 (FIG. 4C), and stores the refractive power a at the position where the coincidence signal is obtained.

When the power of the distance portion is small (for example, ± 0.25 D or less), since the change in the amount of prism is small, the accuracy of the apparatus and the surface accuracy of the lens are affected, so that good alignment accuracy cannot be obtained. Sometimes. Therefore, when it is detected that the lens has a small power, the position where the prism is near 0 and the value of which is the minimum from the change in the cylinder value may be treated as the position on the distance portion axis.

When the target 31 coincides with the marker 32, a horizontally long rectangular target 33 is displayed above the marker 32 in place of the target 31 (FIG. 4D).
Move the measuring point to the upper side of the lens and mark the target 33
Adjust to the mosquito 32 (e in FIG. 4). In this case, the movement of the target 33 is performed when the test lens moves a predetermined distance (several mm) converted from the prism value in the vertical direction of the lens.
Control is performed so as to match the marker 32. The refractive power b at the position where the matching signal is obtained is stored.

By comparing the stored spherical powers of the refractive powers a and b, it is determined whether the current measurement point is in the progressive portion or in the vicinity of the distance portion that has left the progressive portion. When the difference between the two spherical powers is within a predetermined range (= approximately 0), it is determined that the measurement point is in the vicinity of the distance portion. It is possible).

(A) When it is determined that the measurement point is near the distance portion. In this case, the marker 32 is displayed above the target 33 (FIG. 5A). The marker 32 is only for indicating the moving direction of the target 33. Target 33
The measurer moves the lens to be examined to the front side such that moves toward the marker 32. The refractive power is continuously measured during the movement, and the microcomputer 25 converts the movement distance from the prism amount of the lens and detects a change in the addition power per unit movement amount. When it is detected that the measured position has entered the progressive portion from the change in the addition per unit travel distance, the target 33 changes its shape into a round target 34, and the target 33 is positioned below the round target 34. The marker 32 is displayed (FIG. 5)
B). Note that a position where the value increases by a fixed amount (for example, 0.12D) from the value of the spherical power of the refractive power b may be detected.

The distance from the addition start position to the distance portion differs depending on the type of progressive lens and the addition power, and is not constant.
With respect to progressive lenses currently on the market, the upper side of the addition start position by a few mm (4 to 8 mm) corresponds to the distance portion area specified by each lens manufacturer. When the movement distance is converted from the amount of the prism measured in the vertical direction of the lens and the lens is moved a predetermined distance (6 mm in this embodiment), the target 34 and the marker 32 are displayed in agreement. In the present embodiment, focusing on the fact that the distance portion is indicated by an area having a certain area, in order to simplify the processing, to move a fixed distance from the measurement point detected as the progressive portion, The movement may be based on a position that is increased by a fixed amount from the value of the spherical power of the refractive power b. When a signal indicating that the lens has moved a predetermined distance is obtained,
The mosquito 32 changes its shape to a cross-shaped marker 35 to notify that they match (FIG. 5c). The microcomputer 25 detects that the measured value at the distance measuring point has stabilized, and stores the measured value in the microcomputer 25.

When the microcomputer 25 confirms that the measured value of the distance portion has been stored, the microcomputer 25 automatically moves to the near portion measurement step (d in FIG. 5). By automatically shifting from the distance portion measurement step to the near portion measurement step, the displacement of the lens to be inspected due to the switch operation is eliminated. 3
Reference numeral 6 denotes a target for the near portion measurement step. The near portion is measured by moving the target 36 upward from the far portion measurement point (the measurement point is moved below the lens). The movement of the target 36 is performed by converting the change in the amount of prism in the vertical direction of the lens into the amount of movement, but the movement of the target 36 causes the measurement point to be imaged as proceeding through the progressive portion. When the change in the prism amount is converted into a movement amount, a measurement error is likely to occur when the refractive power is small. Therefore, when the refractive power is smaller than a predetermined amount (for example, 0.5 D or less), based on the increase amount of the addition power. Determine the amount of movement. Further, the same processing is performed on a lens whose prism change is disturbed.

While moving the progressive section, the apparatus performs continuous measurement, displays the measured addition on the display section 37, and also displays this on the bar graph 38. This allows the examiner to know the approximate degree of addition and the state of the change even before the near vision measurement is completed.

The apparatus detects the difference between the column power at the measurement position and the column power at the distance portion, and numerically displays the difference on the display unit 39 as the amount of optical distortion. 0.25D) is monitored. If the amount exceeds the predetermined reference amount, the measured value for determining the addition is canceled and the deviation from the direction is obtained by the prism value in the left and right direction of the lens, and the position is deviated from the progressive portion. -Display the get 36 (FIG. 5e,
f). As described above, for a measurement error in a lens having a small refractive power, the change (whether or not to increase) in the amount of optical distortion due to the movement of the lens by the operator (obtained from data such as the change in the amount of prism) is measured. Corrected to the standard.

In this manner, the measurement is performed up to the lower side of the spectacle frame, and if the target 36 is located substantially at the center between the left and right sides, the measurement of the near portion is completed (g in FIG. 5).

(B) When it is determined that the measurement point is in the progressive portion. In this case, the target 33 is displayed on the marker 32 (FIG. 6A), and the measurement point is moved to the upper side of the lens to move the target 33 in the direction of the marker 32. Marker 3
Numeral 2 merely indicates the moving direction of the target 33.
The apparatus continuously measures the dioptric power, converts the moving distance based on the amount of prism of the lens, and detects a change in addition per unit moving distance. A position where the change in addition per unit movement amount is equal to or less than a predetermined value (0.03 D / mm in the embodiment) is determined as a position where the progressive portion has been removed, and a measuring point is a predetermined distance (about 2 mm) from this position. When it is detected that it has moved and entered the distance portion, the marker 32 changes its shape to a cross-shaped marker 35 to notify that they match (FIG. 6B). The microcomputer 25 detects that the measured value at the distance measuring point has stabilized, and stores the measured value in the microcomputer 25. After storing the measured value at the distance portion measurement point, the near portion measurement is performed in the same manner as (a).

[0050]

Embodiment 2 The configuration of Embodiment 2 is different from that of Embodiment 1 in that
A feature is that a position detecting mechanism for the lens to be inspected is added, and the display position of the target 33 is determined using the detection result. Since the refractive power measurement system itself is the same as that of the first embodiment, a description thereof will be omitted.

FIG. 7 is a sectional view of the mechanism for detecting the position of the lens to be inspected, and FIG. 8 is a sectional view taken along line AA. Reference numeral 8 denotes a backing plate for pressing a frame (in the figure, the lens L is simply placed), and 41 denotes a guide pin. Reference numeral 42 denotes a rack, which is held in the internal space of the backing plate 8 so as to be movable horizontally and horizontally, and a guide pin 41 is fixed to the rack 42. A coil spring 43 biases the guide pin 41 leftward (upward in FIG. 7). The rack 44 is supported movably in the front-rear direction of the apparatus, and the backing plate 8 is fixed to the rack 44, so that the backing plate 8 is movable in the front-rear direction with respect to the apparatus. Reference numeral 45 denotes a spring that constantly biases the backing plate 8 forward.

A pinion 47 attached to a rotatable rotating shaft 46 meshes with the rack 42, and the pinion 47 moves in the front-rear direction integrally with the rack 44. The amount of rotation of the pinion 47 is transmitted to the gear 48 via the rotation shaft 46. The amount of rotation of the gear 48 is detected by a potentiometer 49. A pinion 50 meshes with the rack 44,
The rotation amount of the pinion 50 is detected by the potentiometer 51. These signals are processed and input to a microcomputer. By moving the lens L while making contact with the abutment plate 8 and the guide pin 41 in this manner, the amount of movement of the lens L is detected, and the target and marker display positions are detected based on the detected information. Is determined.

In the first embodiment, the change in the amount of prism in the vertical direction (or the left and right direction) of the lens is converted into the moving distance of the lens to be measured (measurement point). The only difference is that direct detection is performed, and a description of the operation of the apparatus is omitted.

In contrast to the first embodiment, the apparatus according to the second embodiment can accurately detect the amount of movement of the lens to be inspected. Therefore, when the measurement point deviates from the progressive portion, it can accurately determine whether the measurement point has left or right. The target can be moved in proportion to the amount of movement of the lens to be inspected. In addition, since the position of the near portion can be determined with high accuracy by displaying the distance from the far portion, the addition can be accurately obtained.

In the above embodiment, various transformations can be performed, and only the positional relationship between the target and the marker is displayed without providing two curves simulating a progressive portion (band). Alternatively, the progressive portion (band) may be moved with respect to the target. Thus, the examples are not intended to limit the embodiments of the present invention.

It is not always necessary to perform all the steps described in the embodiment. For example, when the right and left prisms become 0 in the process of obtaining the power in the distance portion, if the examiner determines that the distance portion is in the distance portion, a switch may be provided to omit the operation of obtaining the addition start position. Alternatively, at the time of transition to the near portion measurement, if it is not necessary to see the change in the addition of the progressive portion, the operation may be performed so as to determine the left and right positions.

[0057]

According to the present invention, a highly reliable addition measurement can be performed even with a progressive lens which has been subjected to special processing called prism thinning. Further, the addition can be measured without depending on the skill of the measurer.

[Brief description of the drawings]

FIG. 1 is an external view of an apparatus of the present embodiment.

FIG. 2 is an optical layout diagram showing a measurement optical system.

FIG. 3 is a block diagram showing a control method of the device.

FIG. 4 is an explanatory diagram showing a display on a screen of a display 1;

FIG. 5 is an explanatory diagram showing another mode of the display of the screen of the display 1.

FIG. 6 is an explanatory diagram showing still another mode of the display on the screen of the display 1.

FIG. 7 is a cross-sectional view showing a mechanism for detecting a position of a backing plate and a guide pin.

FIG. 8 is a sectional view taken along line AA of FIG. 7;

[Explanation of symbols]

 1 Display 5 Progressive Lens Measurement Switch 25 Microcomputer 31, 33, 34, 36 Target 32 Marker 37 Display 38 Bar Graph

Claims (1)

[Claims] 1. A lens meter for projecting measurement light onto a lens to be measured, detecting the trajectory of the measurement light transmitted through the lens to be measured by a light receiving element, and measuring the optical characteristics of the lens to be measured based on the detection result. In the above, the mode switching means for switching to the progressive lens measurement mode, the measurement control means for continuously measuring the refractive power at predetermined intervals, and when the mode is in the progressive lens measurement mode by the mode switching means. Is a display that displays a graphic figure having an area simulating a progressive zone to guide the measurement point, and a position where the amount of prism in the left-right direction becomes almost 0 when the test lens is assumed to be a spherical lens. A marker which is a target to be moved to a corresponding position is displayed on the display based on a measurement result measured by the control of the measurement control means, the target indicating a current measurement point for the marker. Guidance means, a storage means for storing the measurement result when the measurement point is in the distance section area, and a measurement result of the distance section area and the current measurement for moving the measurement point toward the near section. A lens meter provided with monitoring means for monitoring whether the measuring point has deviated to the left or right from the progressive zone based on the result.