JPS61280544A - Automatic lens meter - Google Patents

Abstract

PURPOSE:To simplify the constitution of the title meter and to make said meter effective even from the aspect of quantity of light, by chopping measuring luminous flux transmitted through a lens to be inspected by slit openings different in an angle of inclination to receive the same by photoelectric converter elements constituting a pair. CONSTITUTION:The measuring luminous flux emitted from a LED light source 1 and transmitted through a lens 7 to be inspected through a condenser lens 2 condensing said luminous flux to an iris 4 and an image forming lens 5 is converted to parallel luminous flux by a collimator lens 14 while said parallel luminous flux is chopped by a chopper 15 having slit openings 16a, 16b of which the angles of inclination are different by + or -45 deg.. The resulting chopped luminous fluxes are received by a phtoelectric converter 9 formed of phtoelectric converter elements constituting a pair. Then, the refractive power of the lens 7 is automatically measured from the output phase difference between the photoelectric converter elements constituting an pair with a slit angle-of-inclination discriminating signal. By this method, it is unnecessary to use a plurality of light sources and constitution becomes simple and it is also unnecessary to perform adjustment so as to make different quantities of light same and the title lens becomes effective from the aspect of quantity of light and refractive power can be automatically and rapidly measured with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic lens meter for measuring the refractive power of various lenses such as eyeglass lenses.

[Conventional technology]

Conventionally, various improvements have been made to automatic lens meters in order to simplify the mechanism, facilitate manufacturing, adjustment, etc., shorten measurement time, and improve measurement accuracy. The lens meter shown in the publication was provided.

The lens meter transmits a measurement light flux through a lens to be tested, receives the transmitted light flux with two pairs of photoelectric conversion elements, and also inserts slit apertures, all of which have the same inclination angle with respect to the scanning direction, in two known directions. The refractive power was measured by selectively scanning and chopping the transmitted light beam, and inputting the phase difference between the output signals between the photoelectric conversion elements constituting each pair to a calculation means.

An image splitting prism, an image matching prism, or the like is used as means for selectively scanning the slit opening in two known directions.

However, the lens meter disclosed in JP-A-57-168137 requires an image splitting prism, an image matching prism, etc. as described above, and is not effective in terms of light quantity, reducing measurement accuracy. It had the disadvantage that it could not be simplified mechanically and was not easy to manufacture.

[Problem that the invention seeks to solve]

The present invention eliminates the drawbacks of the prior art described above, and provides a lens meter that does not require the use of an image splitting prism, an image matching prism, etc., has a simple mechanism, is advantageous in terms of light quantity, and has good measurement accuracy. That is.

[Means for solving problems]

In order to solve the above problems, the present invention transmits a measurement light flux through a test lens, receives the transmitted light flux by two or more pairs of photoelectric conversion elements, and chops the transmitted light flux by scanning a slit aperture. In the apparatus for measuring the refractive power of the lens to be tested based on the phase difference of output signals between the photoelectric conversion elements constituting each pair, the inclination angle of the slit opening with respect to the scanning direction of the slit opening is an output device for outputting a discrimination signal of the inclination angle of the slit aperture chopping the transmitted light beam, and inputting the discrimination signal and the phase difference to the calculation means; It has a configuration that provides refractive power.

[For production]

According to the present invention, since the inclination angle of the slit aperture that chops the transmitted light beam of the test lens is made to be at two or more different known angles with respect to the scanning direction of the slit aperture, it is possible to scan only in one direction. This is substantially equivalent to chopping the transmitted light beam of the lens to be inspected by selectively scanning slit apertures that all have the same inclination angle with respect to the scanning direction in two known directions.

Therefore, according to the present invention, there is no need for conventional image splitting prisms, image matching prisms, etc., the mechanism becomes simple, and it is advantageous in light quantity and measurement accuracy is improved.

〔Example〕

Hereinafter, the present invention will be described in detail based on one embodiment.

Figure 1 is a configuration diagram of the optical system of this embodiment.

In the figure, the LED light source that emits the measurement light beam is composed of five LEDs lc, IA, lc, ld, and 1g. As shown in Figure 2, which shows the L-L arrow view in Figure 1, the pair of LEDs 1α and 1s are located on a line made +450 degrees from the line perpendicular to the measurement optical axis OVc in the plane of the drawing I 0 and the other pair of LEDICs
, ld are arranged on a line making an angle of -45° with respect to the line perpendicular to the measurement optical axis 0 in the plane of the drawing 1, and symmetrically to the measurement optical axis O, and the LED 1g is arranged on the measurement optical axis 0. .

However, the arrangement of the LEDs 1α to 1d can be changed as appropriate. In addition, in the case of drawing examples.

As will be described later, the LEDs Iα to 1d are involved in measuring the refractive power of the lens 7 to be tested, and the LED Le is involved in measuring the amount of prism of the lens 7 to be tested.

Therefore, when measuring only the refractive power of the lens 7 to be tested, the LED 1g is not particularly necessary.

Further, 2 is a condenser lens that condenses the luminous flux from the LED light source 1 onto an aperture 4. 3 is an aperture diaphragm, as shown in Figure 3, which shows the M-M line arrow view in Figure 1, the above-mentioned L
It has openings 3α to 3g corresponding to LEDs 1g to 1g of the ED light source 1, respectively. Reference numeral 4 denotes a diaphragm having an aperture 4α, and is shaped as shown in the plan view of the diaphragm 4. Further, 5 indicates the apertures 3α to 3# of the aperture stop 3,
This is an imaging lens that forms an image on the surface of the lens holder 6 that holds the lens 7 to be tested. Note that it is desirable that the aperture 4 be located near the focal point of the imaging lens 5.

Therefore, the light flux emitted from the LED light source 1 is condensed by the condenser lens 2 onto the aperture 4α of the aperture 4, and the aperture 30 of the aperture 30
α to 3g, further passes through the aperture 4α of the diaphragm 4, and after passing through the imaging lens 5, it becomes a substantially parallel light beam and forms an image corresponding to the apertures 3α to 3# on the inner surface of the test lens 7, Further, the light passes through the lens 7 to be tested.

For the purpose of explanation, the above LED light source 1 and condenser lens 2 are
, the aperture diaphragm 3, the diaphragm 4, the imaging lens 5, the lens holder 6, and the test lens 7 are referred to as a measurement light flux optical system 8, but the measurement light flux optical system 8 may have another configuration. For example, instead of the measuring beam optical system 8 shown in FIG. 1, a measuring beam optical system having a configuration as shown in FIG. 5 or 6 may be used. In Fig. 5 of the fang and Fig. 6 of the spear, the same components as in Fig. 1 of the spear are given the same reference numerals. In Fig. 5, 9 is a filament, and 10 is a collimator lens.

In addition, in Figure 6, 11 is a point light source, 12 is a collimator lens, and 13 is an aperture diaphragm configured similarly to the aperture diaphragm 3 in Figure 1 and attached to the lens holder 6.

Further, in the fang 1 diagram, reference numeral 14 is a collimator lens, and it is desirable that one focal point is located near the surface of the lens holder 6 and the other focal point is located near the surface of the rotary chopper 15. The rotary chopper 15 has a slit opening 16α which will be described in detail later.

16h is provided, and the rotary chopper 15 is rotated in one direction by a motor 17.

Further, reference numeral 18 denotes an imaging lens that images the aperture formed on the surface of the lens holder 6 onto the light receiving surface of the photoelectric converter 19. The light-receiving surface of the photoelectric converter 19 is provided with the aperture stop 3, as shown in Figure 7, which shows the N-N arrow view in Figure 1.
Photoelectric conversion elements 2 respectively corresponding to apertures 3α to 3e of
0α to 20g are provided.

Therefore, as described above, the aperture 3 that passes through the test lens 7
The luminous flux based on the apertures 3α to 3e is focused on the surface of the rotary chopper 15 by the collimator lens 14, is chopped by the rotary chopper 15, and is further divided into the slit apertures 16α or 16A of the rotary chopper 15.
The completely transmitted light flux is projected onto the photoelectric conversion elements 20α to 20e.

In the present invention, the inclination angle of the slit opening for chopping the transmitted light beam of the test lens 7 with respect to the scanning direction is set to two or more different known angles.

In the case of the embodiment shown in the drawings, as shown in the fang 8 diagram showing the developed view of the rotary chopper 15, the inclination angle of the fang 1 slit opening 16α with respect to the rotational direction The angle is 145°. However, other angles may be used, or three or more different known angles may be used. Further, the slit openings may be arranged in any arbitrary manner.For example, instead of the rotary chopper 15, a spear 1 as shown in the illustration of the spear 9 may be used.
It is also possible to use a rotary chopper 2) in which the arrangement of the slit opening 16α and the second slit opening 16A is changed. Note that FIG. 119 shows a developed view of the rotary chopper 2). Note that it is actually preferable that the shape of the slit opening has a constant inclination angle.

Further, in the present invention, an output device 22 is provided that outputs a determination signal (hereinafter simply referred to as a determination signal) indicating at what angle of inclination the slit aperture is chopping the transmitted light beam of the test lens 7.

In the case of the embodiment shown in the drawings, the output device 22 is, for example, a rotary chopper 1 corresponding to the positions of the slit openings 16α, 16b.
A sensor that detects the rotation angle of 5 is used.

In the case of the embodiment shown in the drawings, as shown in ilO, the photoelectric conversion elements 20α, 20h, 20C and 20d are each connected to a waveform shaping circuit 23/1. , 23h, 23C and 23d. A pair of waveform shaping circuits 23α shape the output signals of the pair of photoelectric conversion elements 20α and 20h.

'23h are each connected to the spear 1 phase difference measuring circuit 24, and a pair of photoelectric conversion elements 20? A pair of waveform shaping circuits 23C and 23d each waveform shaping the output signal of 20d.
It is connected to the phase difference measurement circuit 25.

The first phase difference measuring circuit 24 and the second phase difference measuring circuit 25 are connected to an interface 29 of the microcomputer 26. The output device 22 is further connected to the interface 29 of the microcomputer 26, and a discrimination signal is input thereto. microcomputer 26
It mainly consists of a microprocessor (central processing unit) 27, a memory (storage device) 28, and an interface (input/output signal processing circuit) 29.
The outputs of the spear 1 phase difference measuring circuit 24 and the 12 phase difference measuring circuit 25 when 6cL is chopping the transmitted light flux of the test lens 7, and the outputs of the spear 2 slit aperture 16A are chopping the transmitted light flux of the test lens 7. The outputs of the tooth 1 phase difference measuring circuit 24 and the tooth 12 phase difference measuring circuit 25 when the lens The tangential force, that is, the cylinder axis angle θ, the spherical tangential force S, and the cylindrical refractive power C are calculated, and the results are displayed on the display device 30. However, in the case of the embodiment shown in the drawings, the microcomputer 26 also functions as a phase difference correction means and a prism amount calculation means, as will be described later.

Here, the reason why refractive power can be determined by calculation will be described.

Assuming that the lens 7 to be tested is not installed in the lens holder 6, the light beams passing through the apertures 3α to 3d of the diaphragm 3 are directed to a single point on the surface of the rotary chopper 15, as shown in Figures 11 (α) and (b). The light is focused on 3. Then, the spear 1 slit opening 16α is scanned in the arrow X direction as shown in the fang 11 (α), the fang 2 slit opening 16h is scanned in the arrow X direction as shown in the fang 11 (h>), and each slit opening 16α, 16b
are to chop the luminous flux condensed at the single point 3, respectively.

On the other hand, when the test lens 7 is placed in the lens holder 6,
The light beams passing through the apertures 3α to 3d of the diaphragm 3 are focused on corresponding points 3α, 3A3c, and 3d on the surface of the rotary chopper 15, as shown in FIGS. 12 (α) and (6), respectively.

Then, the first slit opening 16α is scanned in the arrow X direction as shown in FIG. 12 (α), the second slit opening 16h is scanned in the arrow X direction as shown in FIG. Each of the above points 3α and 3
The transmitted light flux of the test lens 7 condensed onto h, 3c, and 3d is chopped.

The situation shown in Figures 11 and 12 above is explained in the prior art section, in which the slit openings, which all have the same inclination angle with respect to the scanning direction, are scanned alternatively in two known directions. This is substantially equivalent to chopping the transmitted light beam of 7.

Therefore, when the tooth 1 slit aperture 16α scans and chops the transmitted light flux of the test lens 7, and assuming that the scanning speed is constant, the phase difference between the output signals of the photoelectric conversion elements 20α and 20h The obtained value is Dt, the value obtained from the phase difference of the output signals of the photoelectric conversion elements 20C and 20d is DJ, and the spear 2 slit aperture is 16h.
When scanning and chopping the transmitted light beam of the test lens 7, assuming that the scanning speed is constant, the value obtained from the phase difference between the output signals of the photoelectric conversion elements 20cL and 20b is expressed as DJ, Photoelectric conversion element 2oC, 20
If the value obtained from the phase difference of the output signal of d is referred to as D, then D/ = S + G coNθ −...
−■DJ −−zLn 2θ ・・・・
・・■DJ −−9sin2θ 2 ・・・・・・■Dμ= S +
Csin, θ...■.

Therefore, the unknowns are C, S, and θ, and there are three measured data: D/, DJ (--DJ) *'', so by calculating from the above equation (or ■)■, the cylinder axis angle can be calculated. θ, spherical refractive power S, and cylindrical refractive power C can be determined.

In addition, in the case of the drawing embodiment, the slit opening 16
scanning speed detection means 3 for detecting the scanning speed of α, 16A;
1 is provided. The scanning speed detection means 31 is configured, for example, to output a signal corresponding to the time required when the rotary chopper 15 rotates through a predetermined rotation angle, and the output signal is inputted to the interface 29 of the microcomputer 26. There is.

The microcomputer 26 is also configured to correct the phase difference between the output signals between the photoelectric conversion elements based on the output signal of the scanning speed detection means 31. In other words, the phase difference of the output signals between the photoelectric conversion elements is determined by the slit aperture 16α.
, 16b is inversely proportional to the scanning speed, the phase difference at the actual scanning speed is converted into the phase difference at a predetermined constant scanning speed under the same conditions, and then, by the corrected phase difference, It performs the calculations described above. Therefore, even if the scanning speed of the slit openings 16α and 16h, specifically the rotational speed of the motor 17, fluctuates, highly accurate measurements can be made in the same way as when the rotational speed of the motor 17 is kept strictly constant. Become. In addition,
The above situation is exactly the same in the measurement of the amount of prism, which will be described later.

However, if the rotational speed of the motor 17 is kept strictly constant, the functions of the scanning speed detection means 31 and the microcomputer 26 as phase difference correction means are unnecessary.

Furthermore, in the case of the embodiment shown in the drawings, the amount of prism of the lens 7 to be tested can be measured.

That is, in addition to the photoelectric conversion element 201 described above, a light source 32 and a photoelectric conversion element 33 are provided as a prism amount detection sensor as shown in the figure 1, and the lens 7 to be tested is not installed in the lens holder 6. (In this state, the light flux passing through the aperture 3- of the diaphragm 3 is also
) The photoelectric conversion elements 2og and 33 are arranged so that the generation timings of the output signals of the photoelectric conversion elements 2og and 33 coincide at the point a) where the light is focused on a single point 3 on the surface of the rotating chip 4 15. However, even if the photoelectric conversion elements 20e are not arranged so that their generation timings coincide with each other, the photoelectric conversion elements 20e are arranged in advance.

The phase difference between the output signals of 33 is calculated by the microcomputer 26.
What is necessary is to store it in the memory 28 of.

The photoelectric conversion elements 208 and 33 are connected to waveform shaping circuits 34 and 35 that shape the waveforms of their output signals, respectively. In addition, the waveform shaping circuits 34 and 35 each have 1
The three phase difference measuring circuit 36 is connected to the three phase difference measuring circuit 36, and the three phase difference measuring circuit 36 is further connected to the interface 29 of the microcomputer 26. The microcomputer 26 also functions as a prism amount calculation means, and
The spear 3 when the slit aperture 16α is chopping the transmitted light beam of the test lens 7 corresponding to the aperture 3ε of the diaphragm 3
The output of the phase difference measuring circuit 36 and the spear 2 slit opening 16A
The outputs of the 13 phase difference measuring circuits 36 when chopping the transmitted light flux are respectively stored in predetermined locations in the memory 280, and then the calculations described below are performed between the stored values,
The amount of prism of the lens 7 to be tested is calculated and the result is also displayed on the display device 30.

Here, the reason why the amount of prism can be determined by calculation will be described.

Now, when the test lens 7 is installed in the lens holder 6, if the test lens 7 does not have a prism amount, the aperture 3. The light flux passing through the aperture 3e is focused on a point 3g on the surface of the rotary chopper 15 as shown in Figs. 12 (α) and (A) (the same point as the point 3 in Figs. 12 (α) and (h)). be done.

The light beam focused on the one point 36 is also chopped by the slit openings 16a and 16A in the same way as described above. In this case, the photoelectric conversion element 206
, 33, there is no phase difference between the output signals.

On the other hand, if the lens 7 to be tested has a prism amount, the light flux passing through the aperture 3m of the aperture 3 will be as shown in Figures 13 (α) and (A), as shown in Figures 12 (α) and (A). The light is focused on a point 3e that is shifted by an amount corresponding to the prism amount with respect to the point 3e in h). And spear 1 slit opening 16
α is scanned in the direction of arrow X as shown in Figure 13 (α), and fang 2
The slit opening 16h is scanned in the direction of the arrow X as shown in FIG. 2) In FIGS. 3(α) and 3(A), the condensing points of the light beams passing through the apertures 3α to 3d of the diaphragm 3 are omitted. Therefore, in this case, although the phase of the output signal of the photoelectric conversion element 33 is always constant, the phase of the output signal of the photoelectric conversion element 20g will lag or advance in proportion to the amount of prism. Therefore, the phase difference between the output signals of the photoelectric conversion elements 20g and 33 produces a value corresponding to the amount of prism.

Therefore, when the A1 slit aperture 16G scans and chops the transmitted light beam of the test lens 7 corresponding to the aperture 3e of the aperture 3, assuming that the scanning speed is constant, the photoelectric conversion element 20g , 33 is the value obtained from the phase difference between the output signals of the photoelectric conversion elements 20e and 33. Similarly, when the fang 2 slit aperture 16A chops the transmitted light flux, the value obtained from the phase difference between the output signals of the photoelectric conversion elements 20e and 33 is DI. If the value is Dt, the amount of prism P of the lens 7 to be tested is as follows.

As a result, the unknown quantity is P, and the measured data are DI, D
Since there are two t, by calculating from the above 0 formula,
This means that the prism amount P can be determined.

Hereinafter, the present invention having the above configuration will be explained in detail.

After placing the lens 7 to be tested on the lens holder 6, a measurement switch (not shown) is turned on to start measurement.

When the spear 1 slit aperture 16α is chopping the transmitted light flux of the test lens 7, the microcomputer 2
6 determines the state, and phase difference measuring circuits 24, 25.3
The phase difference data obtained from 6 (generally, an average value measured many times is used) is stored at a predetermined location in the memory 28. Further, when the fang 2 slit opening 16A is chopping the transmitted light beam of the test lens 7, the microcomputer 26 determines the state, and the phase difference measuring circuit 24
, 25 and 36 are stored in different predetermined locations of the memory 28. Incidentally, the scanning speed data of the slit opening 16α or 16b corresponding to each of the above-mentioned phase difference data is also stored at a predetermined location in the memory 28 from the scanning speed detecting means 31.

Next, the microcomputer 26 determines the scanning speed of the slit opening 16α or 16A under the same conditions based on the phase difference data and the scanning speed data at that time (values stored in the memory 28). is corrected to the phase difference when the speed is constant, and then based on the corrected phase difference data, formulas ■～■ or formula ■
The refractive powers of the lens 7 to be tested, that is, the cylindrical axis angle θ, the spherical refractive power S, the cylindrical refractive power C, and the prism -1iP are calculated, and the results are displayed on the display device 30.
will be displayed.

However, if the microcomputer 26 performs calculations based on formulas ■ to ■ or formula ■, the calculations may take a long time.
The constants may change depending on the arrangement of the optical system. Therefore,
In an actual device, after making the device, measurements are performed using a lens whose refractive power and amount of prism are known in advance.
By storing the values of DI to Dt at that time in the memory 28 in correspondence with the above-mentioned known refractive power and prism amount, the above-mentioned inconvenience can be solved. There are three unknowns: θ, S, and C, and the measured data is DI, Dco (-
-D, t), and D4=, and since there is one unknown quantity, P, and the measurement data is two, Dz and D4, the refractive power and the amount of prism are each uniquely determined.

In addition, in the above explanation, the case where two pairs of photoelectric conversion elements involved in the measurement of the refractive power of the test lens 7 were provided was described, but three or more pairs may be provided, or six pairs of photoelectric conversion elements may be provided. The arrangement direction can be arbitrary as long as it is known.

〔Effect of the invention〕

According to the present invention, there is no need to use an image splitting prism, an image matching prism, etc., which were conventionally necessary.

Therefore, the 89 structure can be simplified and the construction can be made easily and inexpensively, and it is advantageous in terms of light weight and measurement accuracy can be improved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 is a configuration diagram of the optical system, Fig. 2 is a view taken along the line L-L in Fig. 1, and Fig. 3 is a diagram of the configuration of the optical system.
Figure 1 is a view taken along arrow M-M in Figure 1, Figure 4 is a plan view of the diaphragm in Figure 1, and Figure 5 is a configuration diagram showing another example of the measuring beam optical system in Figure 1. Figure t-6 is a configuration diagram showing still another embodiment of the measuring beam optical system in Figure 1. ! The tFT diagram is the N-N line arrow view 1 in the fang 1 diagram. The tPS diagram is a developed view of the rotary chopper in Figure 1, Figure 9 is a developed view of another rotary chopper, Figure 10 is a diagram of the rotary chopper of the above example, and Figure 11 (α) and <b) are the test objects. An explanatory diagram showing the chopping state of the lens, Figure 12 (α
) and (Al are explanatory diagrams showing other states of chopping of the tested lens, and Figures 13 (α) and (A) are explanatory diagrams showing still other states of chopping of the tested lens. 7. 0 test lens% 15- ・Rotating chopper, 1
6α, 16A---slit opening, 20a, 20h
, 20C. 20d, 20C... photoelectric conversion element, 22... output device.

Claims (2)

[Claims] (1) Transmitting the measurement light flux through the test lens, receiving the transmitted light flux by two or more pairs of photoelectric conversion elements, and chopping the transmitted light flux by scanning a slit aperture;
In the apparatus for measuring the refractive power of the lens to be tested based on the phase difference of output signals between the photoelectric conversion elements constituting each pair, the slit opening has two or more inclination angles with respect to the scanning direction of the slit opening. An output device is provided which outputs a discrimination signal of the inclination angle of the slit opening which chops the transmitted light beam, and inputs the discrimination signal and the phase difference to a calculation means to determine the refractive power. An automatic lens meter characterized by: (2) The automatic lens meter according to claim 1, wherein the slit opening has two types of inclination angles, +45° and -45°, with respect to the scanning direction.