CN110940495A

CN110940495A - Device and method for measuring prism degree and prism degree difference of eye protector

Info

Publication number: CN110940495A
Application number: CN201911227984.6A
Authority: CN
Inventors: 商景林
Original assignee: SHANGHAI INSTITUTE OF WORK SAFETY SCIENCE
Current assignee: SHANGHAI INSTITUTE OF WORK SAFETY SCIENCE
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2020-03-31

Abstract

The invention relates to a device and a method for measuring the difference between the prismatic degree and the prismatic degree of an eye protector, wherein the measuring device comprises: light source, first convergent lens, head mould, diaphragm, second convergent lens and image device along coaxial arranging in proper order of horizontal direction, wherein: the light source is used for providing a light beam, and the light beam becomes a beam of parallel light after passing through the first converging lens; the head model is provided with a first channel and a second channel which penetrate from the hindbrain to two eyes, and the parallel light beam passes through the first channel and the second channel and is divided into two refracted light beams after being refracted by the eye protector; the diaphragm is provided with a first light through hole and a second light through hole which respectively correspond to the first channel and the second channel, and the two beams of refracted light respectively pass through the first light through hole and the second light through hole and then pass through the second converging lens to respectively form a first converging point and a second converging point on the imaging device. The measuring device and the measuring method have high precision and good repeatability.

Description

Device and method for measuring prism degree and prism degree difference of eye protector

Technical Field

The invention relates to the technical field of detection of individual protective equipment products, in particular to a device and a method for measuring the difference between the prism degree and the prism degree of an eye protector.

Background

Eye-protectors (Eye-protectors) are Protective articles capable of protecting the eyes and face of a person from injury, and belong to one of individual Protective Equipment (Personal Protective Equipment). Eyewear is typically constructed from components such as lenses, frames or head bands, and lenses are a generic term for visually transparent portions (typically made from wire mesh, glass or plastic materials). In the course of doing industrial manufacturing, experimental research, sports activities, etc., there are some risk factors that may cause eye and face damage or vision limitation, such as:

(1) mechanical hazards, such as object strikes, the flying of fine particulate matter, the scratching of tree branches or fibrous materials, hot solid rub-on, etc., account for approximately 70% of the total ocular and facial risk factors.

(2) Radiation hazards, such as laser, ultraviolet, infrared, visible, welding arc, etc., account for approximately 18% of the total ocular and facial risk factors.

(3) Chemical hazards, etc., such as fine dust, aerosols, droplets, fumes, vapors, etc., account for approximately 12% of the total ocular and facial risk factors.

Therefore, the necessary eye protection is required. The eye protectors on the market at present are various, such as glasses, eyepatches, face screens, welding masks and the like, and have different functions corresponding to the eye protectors in different application environments. In order to ensure safe use of the eyewear, the lenses used in the eyewear have specific test items and specifications that are different from those of ordinary spectacle lenses, including the Prism power (Prism power) and the Prism aberration (Prism impedance) of the eyewear lenses.

FIG. 1A is a schematic diagram illustrating the principle of prism measurement, referring to FIG. 1A, a prism 120 is disposed between an eye 110 and an object O, the prism 120 can be a prism or a pair of glasses, the wider plane below the prism 120 is a base 120a of the prism 120, and the tip above the prism 120 is a prism tip 120 b. when a light beam emitted from the object O passes through the prism 120 and enters the eye 110, the light beam is refracted to deflect the light beam in the direction of the base 120a, so that an object image O 'is formed at a position deviated from the object O, which is called prism effect.A definition of prism is that when the eye 110 observes the object O1 meter ahead of the prism 120, the object image O' moves 1cm in the direction of the prism tip 120b, which is called a prism, and is denoted by 1 △, which can also be denoted by 1 cm/m.

The orientation of the prisms is usually marked with the orientation of the prism base. Fig. 1B is a schematic view of the prism base direction. Wherein R denotes a right eye lens and L denotes a left eye lens. As shown in fig. 1B, for one lens, the base directions with four squares are: substrate up (BU), substrate down (BD), substrate in (BI), substrate out (BO). Typically the lens is circular and the prism base is oriented over 360 degrees. The prism power can be decomposed into components of prism power in the horizontal and vertical directions in the direction of the prism base. The algebraic difference of the horizontal prism power components of the left and right eyeglass lenses of the eye protector is referred to as the horizontal prism power mutual difference, and the algebraic difference of the vertical prism power components of the left and right eyeglass lenses of the eye protector is referred to as the vertical prism power mutual difference.

Fig. 2 is a schematic diagram of the difference between the prism powers of the left and right eyeglass lenses of the eye protector. Referring to fig. 2, the object image of the sun S0 seen by the right eye Reye through the right prism Rp is S1, the object image of the sun S0 seen by the left eye Leye through the left prism Lp is S2, and a certain distance exists between S1 and S2. The larger the difference between the prism degrees of the left and right glasses is, the farther the distance between the object images seen by the left and right eyes is, so that the user can feel dizzy when looking away through the glasses, and the peripheral vision can generate the swimming phenomenon when walking or turning around.

When the difference between the prism degree of the eye protector and the prism degree is large, the wearer can see objects with dizziness, brain distension, eye pain, blurred vision and the like, and misoperation of the wearer can be caused seriously, so that safety production accidents are caused.

The table is the technical performance requirement for the difference between the prism degree of the eye protector and the prism degree. If the difference between the prism degree of the eye protector and the prism degree is larger than the requirement in the table I, the eye protector is unqualified and cannot be sold or put into use.

Table one:

lensometers (focimeters) are currently available for measuring the prism power of the lens and the orientation of the prism base. However, the lensmeter measures only the lens itself when measuring the prism, and does not consider how the lens is measured in a worn state after being mounted on the frame, resulting in poor reproducibility of the measurement result. In addition, the lensmeter is also unable to measure the difference between the degrees of prism of the eye protectors.

Disclosure of Invention

The invention aims to provide a device and a method for measuring the difference between the prism degree and the prism degree of an eye protector, which have high precision and good repeatability.

The technical solution adopted to solve the above technical problems is a device for measuring the difference between the degree of prism of an eye protector and the degree of prism, comprising: light source, first convergent lens, head mould, diaphragm, second convergent lens and image device along coaxial arranging in proper order of horizontal direction, wherein: the light source is used for providing a light beam, and the light beam becomes a beam of parallel light after passing through the first converging lens; the head model is provided with a first channel and a second channel which penetrate from the hindbrain to two eyes, and the parallel light beam passes through the first channel and the second channel and is divided into two refracted light beams after being refracted by the eye protector; the diaphragm is provided with a first light through hole and a second light through hole which respectively correspond to the first channel and the second channel, and the two beams of refracted light respectively pass through the first light through hole and the second light through hole and then pass through the second converging lens to respectively form a first converging point and a second converging point on the imaging device.

In an embodiment of the present invention, the light source includes a light emitting device and a light beam adjusting device, and the light beam provided by the light emitting device becomes a divergent stable light beam after passing through the light beam adjusting device.

In an embodiment of the invention, the light emitting device is a laser, and the beam adjusting device is a plano-convex lens.

In an embodiment of the invention, the light emitting device is an incandescent lamp or a tungsten lamp, and the beam adjusting device comprises a filter and a pinhole.

In an embodiment of the present invention, the apparatus further comprises a guide rail, and the light source, the first condensing lens, the head die, the diaphragm, the second condensing lens, and the imaging device are mounted on and movable along the guide rail.

In an embodiment of the invention, the head die further has a first calibrated orifice located between the first and second channels.

In an embodiment of the invention, the diaphragm further has a second collimating aperture located at the center of the diaphragm.

In an embodiment of the present invention, the size of the head model is in accordance with the statistical result of the head data of the adult male in China.

In order to solve the above-described problems, the present invention provides a method for measuring a difference between a prism degree and a prism degree of an eye protector, the method using the measuring apparatus described above, the method comprising: before the eye protector is not worn on the head model, adjusting the measuring device to enable the light beam provided by the light source to form a clear light spot at the central point of the imaging device after passing through the first converging lens, the head model, the diaphragm and the second converging lens; keeping the optical path of the measuring device unchanged, and wearing the eye protector on the head model; blocking a second channel of the head die, measuring a position of the first convergence point formed on the imaging device and a first distance of the first convergence point from the center point; blocking a first channel of the head die, measuring a position of the second convergence point formed on the imaging device and a second distance of the second convergence point from the center point; taking the larger of the first distance and the second distance as the prismatic power of the eye protector; calculating the distance between the first convergence point and the second convergence point in the horizontal direction, and taking the distance as the difference of the prism degrees of the eye protector in the horizontal direction; and calculating the distance between the first convergence point and the second convergence point in the vertical direction to be used as the vertical direction prism degree mutual difference of the eye protector.

In an embodiment of the present invention, the method further includes: and judging the direction of the prism degree substrate of the eye protector according to the position relation between the intersection point of the two beams of refracted light passing through the second condenser lens and the imaging device.

According to the device and the method for measuring the prism degree and the prism degree difference of the eye protector, the special head die is used for wearing the eye protector to be measured, the prism degree and the prism degree difference of the eye protector can be obtained simultaneously, and the measuring result is high in precision and good in repeatability.

Drawings

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, wherein:

FIG. 1A is a schematic diagram of the principle of prism measurement;

FIG. 1B is a schematic view of the prism base orientation;

FIG. 2 is a schematic illustration of the interparticle prismatic power of the left and right eye lenses of the eye protector;

FIG. 3 is a schematic diagram of a device for measuring the difference between the degree of prism and the degree of prism for an eye protector, in accordance with one embodiment of the present invention;

fig. 4A-4C are schematic structural views of a head model in an eye protector cross-prism and cross-prism measurement apparatus in accordance with an embodiment of the present invention;

FIG. 5 is a schematic diagram of a diaphragm in an apparatus for measuring the cross-over between the degree of prism and the degree of prism of an eye protector according to an embodiment of the present invention;

FIG. 6 is an exemplary flow chart of a method for measuring the cross-over between the degree of prism and the degree of prism of an eye protector according to one embodiment of the present invention;

fig. 7 is a schematic diagram of an imaging device in an eye protector cross-prism and cross-prism measurement device in accordance with an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited to the specific embodiments disclosed below.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.

In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of protection of the present application is not to be construed as being limited. Further, although the terms used in the present application are selected from publicly known and used terms, some of the terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Further, it is required that the present application is understood not only by the actual terms used but also by the meaning of each term lying within.

Flow charts are used herein to illustrate operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, various steps may be processed in reverse order or simultaneously. Meanwhile, other operations are added to or removed from these processes.

Fig. 3 is a schematic structural diagram of a device for measuring the difference between the degree of prism and the degree of prism of an eyewear in accordance with an embodiment of the present invention. Referring to fig. 3, the measuring apparatus 300 of this embodiment includes a light source 310, a first condensing lens 320, a head die 330, a diaphragm 340, a second condensing lens 350, and an imaging device 360, which are coaxially arranged in order in a horizontal direction X. As shown in fig. 3, a broken line CC' indicates an axis line, on which each of the devices in the measuring device 300 is left-right symmetrical.

In the measuring device 300 shown in fig. 3, a light source 310 is disposed at one end of the measuring device 300, and the light source 310 is used to provide a light beam which becomes a parallel beam after passing through a first condensing lens 320. In fig. 3, the light source 310 is located at the left end of the measuring device 300, and other components in the measuring device 300 are arranged in order from left to right in the horizontal direction X. It is to be understood that fig. 3 is not intended to limit the location of the light source 310. In other embodiments, the light source 310 may be located at the right end of the measuring device 300, and accordingly, the components of the measuring device may be arranged in sequence from right to left along the horizontal direction X.

In some embodiments, light source 310 includes a light emitting device 311 and a beam shaping device 312. The light emitting device 311 and the light beam adjusting device 312 are disposed adjacent to each other, and the light beam adjusting device 312 is located on a side of the light emitting device 311 close to the first condensing lens 320. The light beam emitted by the light emitting means 311 is adjusted to a diverging stable light beam after passing through the light beam adjusting means 312.

In some embodiments, the light emitting device 311 is a laser and the corresponding beam shaping device 312 is a convex lens. In a preferred embodiment, the beam shaping device 312 is a plano-convex lens, and the side facing the laser 311 is planar and the side facing the first focusing lens 320 is convex. The collimated laser light emitted by the laser device is changed into a divergent stable light beam after passing through the plano-convex lens.

In some embodiments, the light emitting device 311 is an incandescent lamp or a tungsten lamp, and the corresponding beam shaping device 312 includes a filter and a pinhole. The filter is an interference filter having a peak transmittance in a certain wavelength region. The light beam emitted by an incandescent lamp or a tungsten lamp passes through a filter, so that light having a certain wavelength passes through the filter, while light having other wavelengths cannot pass through the filter. The light beam passing through the optical filter passes through the pinhole to become a divergent stable light beam.

In the measuring apparatus 300 shown in fig. 3, the first focusing lens 320 may be a convex lens or a plano-convex lens, and the distance between the first focusing lens 320 and the light source 310 in the horizontal direction X may make the light beam emitted from the light source 310 become a parallel light beam after passing through the first focusing lens 320. It can be understood that the width of the beam of parallel light in the vertical direction Y is related to the diameter of the first focusing lens 320, and the diameter of the first focusing lens 320 is related to the size of the head die 330 to ensure that the beam of parallel light can continue to propagate forward through the head die 330.

The head model 330 is a special head model for measuring the difference between the prism degree and the prism degree of the eye protector. A top view of the head model 330 and eye protector 370 is shown in fig. 3. Referring to fig. 3, the head model 330 has a first channel 331 and a second channel 332 that pass through from the hindbrain to both eyes. The first channel 331 exits the face of the head mold 330 to characterize one eye and the second channel 332 exits the face of the head mold 330 to characterize the other eye. The head model 330 is worn with an eye protector 370 as an object to be measured by the measuring apparatus 300 of the present invention. The eye protector 370 can be stably worn on the head mold 330, and is not easily shaken or dropped.

The parallel light exiting the first condensing lens 320 is divided into two parallel lights after passing through the first and

second channels

331 and 332 of the head die 330. The two parallel beams of light continue through the eye protector 370 and are refracted after passing through the eye protector 370 to form two refracted beams of light. Fig. 3 is only a schematic illustration, and the light beam that passes out of the lens position of the eyewear 370 may not actually reach the stop 340 in parallel, but may be deflected.

The diaphragm 340 has a first light passing hole 341 and a second light passing hole 342 corresponding to the first channel 331 and the second channel 332, respectively. The two refracted lights refracted by the eye protector 370 respectively pass through the first light passing hole 341 and the second light passing hole 342, and then pass through the second converging lens 350, so that a first converging point and a second converging point are respectively formed on the imaging device 360. For example, the second channel 332 of the head die 330 may be blocked or shielded, and the light passes through the first channel 331, is refracted by the eye protector 370, passes through the first and second

light passing holes

341 and 342, and passes through the second focusing lens 350 to form a first focusing point on the imaging device 360. Then the first channel 331 of the head module 330 is blocked or shielded, and the light passes through the second channel 332, is refracted by the eye protector 370, then passes through the first light passing hole 341 and the second light passing hole 342, and then passes through the second converging lens 350, and forms a second converging point on the imaging device 360. It will be appreciated that the diaphragm 340 acts to limit the beam.

In some embodiments, the second converging lens 350 is a convex lens or a plano-convex lens. The second condenser lens 350 has a length in the vertical direction Y sufficient to receive the light beams that have passed through the first and second

light passing holes

341 and 342 of the diaphragm 340.

The distance between the imaging device 360 and the second condensing lens 350 is such that the refracted light beam after passing through the stop 340 is condensed on the imaging device 360 after passing through the second condensing lens 350. The specific implementation of the imaging device 360 is not limited in the present invention, and the imaging device 360 may be a blank image screen, an image screen printed with scales or squares, or an image screen with a photo sensor distributed on the surface. In summary, when the light beams are converged on the imaging device 360 after passing through the second converging lens 350 to form a convergence point, a measurer can directly obtain position information of the convergence point by measuring or reading, etc.

In some embodiments, the measuring device 300 of the present invention further comprises a guide rail extending along the horizontal direction X. The light source 310, the first condensing lens 320, the head die 330, the diaphragm 340, the second condensing lens 350 and the imaging device 360 of the measuring apparatus 300 are all mounted on the guide rail and can be moved along the guide rail, and can be fixed at a desired position when moved thereto. The guide rail may have a graduated scale thereon to facilitate direct access to the distances between the various components. The distances in the vertical direction Y of the light source 310, the first condensing lens 320, the head die 330, the stop 340, the second condensing lens 350, and the imaging device 360 may also be adjusted to align the central axes of these components.

Fig. 4A-4C are schematic structural views of a head model in an eye protector cross-prism and cross-prism measurement apparatus in accordance with an embodiment of the present invention. Fig. 4A-4C show the specific structure of the head die 330 from three different angles, respectively. In fig. 4A, which is a front view of the head mold 330, referring to fig. 4A, the left and right width of the skull on the front side of the head mold 330 is 152mm, and the first passage 331 and the second passage 332 in the two-eye region have the same aperture, which is 32 mm. Fig. 4B is a side view of the head model 330, and referring to fig. 4B, the front-back width of the head model 330 from the forehead to the hindbrain is 185.85mm, and the distance of the head model 330 from the chin to the crown is 226.8 mm. As shown in FIG. 4B, the back head of the head module 330 has an opening 333, and the position of the opening 333 is the same as that of the first and

second channels

331, 332, so that the light beam can pass through from the back head of the head module 330 to both eyes. FIG. 4C is a rear view of the head die 330, and referring to FIG. 4C, the head die 330 has a posterior opening 333 with a height of 39mm in the vertical direction Y, which is larger than the apertures of the first and

second passages

331 and 332 by 32 mm; the width of the opening 333 in the horizontal direction X is 110 mm. Also indicated in FIG. 4C is a 64mm hole spacing between the first channel 331 and the second channel 332.

It should be noted that the above data regarding the head module 330 are only examples and are not intended to limit the scope of the present invention. It is understood that the shape data of the human head varies according to different races, sexes, ages, and the like. The size of the head die 330 in the measuring device of the present invention can be determined according to actual needs. For example, for eye protectors sold to europe, the head model may be constructed from head data of european ethnic groups; for the eye protector for children, head molds and the like of different sizes can be constructed according to head data of children of different ages.

In some embodiments, the size of the head model in the measuring device of the invention is in accordance with the statistical result of the head data of Chinese adult male. The invention carries out statistics and analysis on the head data of adult men in China to obtain the size of the head model, so that the head model can have universal representativeness, thereby better reflecting the situation after the eye protector is worn and further obtaining more real measurement results of the prism degree and the prism degree difference of the eye protector.

Fig. 5 is a schematic structural diagram of a diaphragm in the apparatus for measuring the cross-over between the degree of prism and the degree of prism of the eye protector according to an embodiment of the present invention. Referring to fig. 5, the stop 340 is circular. Two circular holes are provided at two sides of the center position 343 of the diaphragm 340 at equal distances in the horizontal direction X, and correspond to the first light passing hole 341 and the second light passing hole 342 of the diaphragm 340 shown in fig. 3.

In a preferred embodiment of the present invention, the laser as the light emitting device 311 provides a light beam wavelength of 600 ± 70 nm; the focal length of the plano-convex lens as the beam adjusting means 312 is 15 mm; the first focusing lens 320 and the second focusing lens 350 are identical, and have nominal diameters of 100mm and focal lengths of 1 m; the aperture of the first and second

light passing holes

341 and 342 of the diaphragm 340 is 8mm, and the distance between the first and second

light passing holes

341 and 342 is 32 mm.

Fig. 6 is an exemplary flow chart of a method for measuring the cross-over between the degree of prism and the degree of prism of an eyewear in accordance with an embodiment of the present invention. The measurement method uses the measurement device 300 described above to measure the prism and the cross-prism of the eyewear. Accordingly, the foregoing description of the measurement apparatus 300 and the associated drawings may be used to illustrate the measurement method. As shown in fig. 3 and fig. 6, the measurement method of this embodiment includes the following steps:

in step 610, before the eyewear 370 is worn on the head module 330, the measuring device 300 is adjusted to form a clear spot at the center of the imaging device 360 after the light beam provided by the light source 310 passes through the first focusing lens 320, the head module 330, the stop 340 and the second focusing lens 350.

Fig. 7 is a schematic diagram of an imaging device in an eye protector cross-prism and cross-prism measurement device in accordance with an embodiment of the present invention. Referring to fig. 7, the image forming apparatus 360 is the image forming apparatus 360 shown in fig. 3. It is to be understood that fig. 7 is a diagram for illustrating the method of measuring the difference between the degree of prism and the degree of prism of the eyewear of the present invention, and is not intended to limit the size, shape, materials, etc. of the imaging device 360. Referring to fig. 7, at step 610, a sharp spot is formed at the center point 361 of the imaging device 360. Fig. 7 is not intended to limit the size of the spot.

In some embodiments, as shown with reference to fig. 4A and 4C, a first calibrated hole 334 is further included at a position between the two eyes of the head mold 330, the position of the first calibrated hole 334 in the horizontal direction X being flush with the first and

second passages

331 and 332 of the head mold 330, at the bridge of the nose of the head mold 330. Referring to fig. 4A, the first alignment hole 334 has a hole diameter of 10 mm. Referring to FIG. 5, a second alignment aperture 344 is also included at a center location 343 of the aperture 340. In some embodiments, the aperture of the second collimating aperture 344 is the same as the aperture of the first clear aperture 341 and the second clear aperture 342 of the diaphragm 340, both 8 mm. The first and second

light passing holes

341 and 342 are equidistant from the second collimating hole 344.

The first alignment hole 334 of the head die 330 and the second alignment hole 344 of the diaphragm 340 are used together to positionally align the measuring device 300 in step 610. the light beam provided by the light source 310 passes through the first alignment hole 334 and the second alignment hole 344, and a clear light spot is formed at the center point 361 of the imaging device 360 by adjusting the positions of the respective components in the measuring device 300 in the horizontal direction X and the vertical direction Y.

In step 620, the optical path of the measurement device 300 is kept unchanged, and the eyewear 370 is worn on the headform 330.

It should be noted that after step 610 and/or step 620 are completed, at least one of the first calibration hole 334 and the second calibration hole 344 needs to be blocked, so that when the prism degree and the prism degree of the eyeware 370 are measured to be different from each other, only the light passing through the first channel 331 and the second channel 332 on the head die 330 reaches the diaphragm 340.

The second channel 332 of the head die 330 is blocked, and the position of the first convergence point 362 formed on the imaging device 360 and the first distance d1 of the first convergence point 362 from the center point 361 are measured, step 630.

Referring to fig. 7, the first convergence point 362 is formed by the light beam passing through the first passage 331 of the head die 330. Thus, the first convergence point 362 is used to calculate the prismatic power and the prismatic power cross-over of the lens at the eye protector 370 corresponding to the first channel 331.

The first pass 331 of the head die 330 is blocked, and the position of the second convergence point 363 formed on the imaging device 360 and the second distance d2 of the second convergence point 363 from the center point 361 are measured, step 640.

Referring to fig. 7, the second convergence point 363 is formed by the light beam passing through the second channel 332 of the head die 330. Thus, the second convergence point 363 is used to calculate the prism and the cross-prism of the lens at the second channel 332 corresponding to the eyeguard 370.

It should be noted that the first distance d1 and the second distance d2 obtained according to

steps

630 and 640 are vectors.

Step 650, take the greater of the first distance d1 and the second distance d2 as the prismatic power of the eyeguard 370.

Referring to fig. 3, in a preferred embodiment of the present invention, the focal length of the second condensing lens 350 is 1m, that is, the distance between the second condensing lens 350 and the imaging device 360 is 1m, the first distance d1 and the second distance d2 can be directly used as the prism of the two lenses of the eyewear 370 according to the calculation principle of the prism illustrated in fig. 1A. In other embodiments, when the distance between the second condensing lens 350 and the imaging device 360 is not 1m, the prism power of the two lenses of the eye protector 370 may be obtained by numerical calculation.

According to the requirement of Table one, the requirement for the prismatic power of an eye protector is not greater than 0.12 △, and therefore the greater of the first distance d1 and the second distance d2 is taken as the prismatic power of the eye protector, and if the greater is greater than 0.12 △, the eye protector is not qualified.

In some embodiments, where the imaging device 360 shown in fig. 7 is a blank image screen, the first distance d1 and the second distance d2 may be measured using a measuring tool; in other embodiments, where the imaging device 360 has graduated squares printed thereon, which may have an accuracy of 1mm, the first distance d1 and the second distance d2 may be read directly. The measurement of the first distance d1 and the second distance d2 is not the focus of the present invention, and the skilled person may obtain the first distance d1 and the second distance d2 in any way.

In step 660, the distance between the first convergence point 362 and the second convergence point 363 in the horizontal direction is calculated as the difference between the horizontal direction prism degrees of the eye protector 370.

In step 670, the distance between the first convergence point 362 and the second convergence point 363 in the vertical direction is calculated as the vertical direction prism degree difference of the eye protector 370.

Both the horizontal direction cross-prism difference in step 660 and the vertical direction cross-prism difference in step 670 can be calculated by the first distance d1 and the second distance d 2. For example, the sum of the components of the first distance d1 and the second distance d2 in the horizontal direction X is the distance between the first convergence point 362 and the second convergence point 363 in the horizontal direction X; the sum of the components of the first distance d1 and the second distance d2 in the vertical direction Y is the distance between the first convergence point 362 and the second convergence point 363 in the vertical direction Y.

Through steps 610 to 670, the prismatic power and the prismatic power mutual difference of the eye protector 370 can be obtained.

In some embodiments, the measurement method of the present invention further comprises determining the direction of the prismatic power base of the eye protector from the positional relationship between the intersection of the two refracted light beams after passing through the eye protector after passing through the second condenser lens 350 and the imaging device 360. In these embodiments, the first passage 331 or the second passage 332 of the head die 330 is not obstructed. The light beams passing through the first and

second channels

331 and 332 of the head die 330 form a crossing point after passing through the second condensing lens 350, and if the crossing point is located before the imaging device 360 (i.e., between the imaging device 360 and the second condensing lens 350 in fig. 3), it is judged that the prismatic base of the eye protector 370 faces inward; if the intersection point is located behind the imaging device 360 (i.e., to the right of the imaging device 360 in fig. 3), then the prismatic base of the eye protector 370 is judged to be facing outward. According to the difference between the orientation and the horizontal prism degree obtained in the previous step, the first comparison table is used for evaluating whether the performance of the horizontal prism degree difference of the eye protector is qualified or not.

According to the measuring method, the measurement of the difference between the prism degree and the prism degree of the eye protector can be simultaneously completed, so that the tests of two optical performances of the prism degree and the prism degree difference of the eye protector can be further obtained; the test process and data reading are visual and clear; because the eye protector can be worn on the head model stably, the condition in actual use is well simulated, and the accuracy and the repeatability of the measuring result are ensured.

Although the present invention has been described with reference to the present specific embodiments, it will be appreciated by those skilled in the art that the above embodiments are merely illustrative of the present invention, and various equivalent changes and substitutions may be made without departing from the spirit of the invention, and therefore, it is intended that all changes and modifications to the above embodiments within the spirit and scope of the present invention be covered by the appended claims.

Claims

1. The utility model provides a measurement device that eye protector prism degree and prism degree are poor each other which characterized in that includes: light source, first convergent lens, head mould, diaphragm, second convergent lens and image device along coaxial arranging in proper order of horizontal direction, wherein:

the light source is used for providing light beams, and the light beams become a beam of parallel light after passing through the first converging lens;

the head model is provided with a first channel and a second channel which penetrate from the hindbrain to two eyes, and the parallel light beam passes through the first channel and the second channel and is divided into two refracted light beams after being refracted by the eye protector;

the diaphragm is provided with a first light through hole and a second light through hole which respectively correspond to the first channel and the second channel, and the two beams of refracted light respectively pass through the first light through hole and the second light through hole and then pass through the second converging lens to respectively form a first converging point and a second converging point on the imaging device.

2. A measuring apparatus according to claim 1, wherein the light source comprises a light emitting device and a beam shaping device, the light beam provided by the light emitting device passing through the beam shaping device to become a diverging, stable light beam.

3. A measuring device according to claim 2, wherein the light emitting means is a laser and the beam modifying means is a plano-convex lens.

4. A measuring device according to claim 2, wherein the light emitting means is an incandescent lamp or a tungsten lamp and the beam modifying means comprises a filter and a pinhole.

5. The measurement device of claim 1, further comprising a guide rail, the light source, the first converging lens, the head die, the diaphragm, the second converging lens, and the imaging device being mounted on and movable along the guide rail.

6. The measurement device of claim 1, wherein the head die further has a first calibrated orifice located between the first and second channels.

7. The measurement device of claim 1, wherein the diaphragm further has a second calibration aperture centered on the diaphragm.

8. The measurement device of claim 1, wherein the size of the head model is in accordance with the statistical results of the head data of the adult male in china.

9. A method of measuring the difference between the degree of prism and the degree of prism of an eyewear using the measurement device of any of claims 1-8, comprising:

before the eye protector is not worn on the head model, adjusting the measuring device to enable the light beam provided by the light source to form a clear light spot at the central point of the imaging device after passing through the first converging lens, the head model, the diaphragm and the second converging lens;

keeping the optical path of the measuring device unchanged, and wearing the eye protector on the head model;

blocking a second channel of the head die, measuring a position of the first convergence point formed on the imaging device and a first distance of the first convergence point from the center point;

blocking a first channel of the head die, measuring a position of the second convergence point formed on the imaging device and a second distance of the second convergence point from the center point;

taking the larger of the first distance and the second distance as the prismatic power of the eye protector;

calculating the distance between the first convergence point and the second convergence point in the horizontal direction, and taking the distance as the difference of the prism degrees of the eye protector in the horizontal direction;

and calculating the distance between the first convergence point and the second convergence point in the vertical direction to be used as the vertical direction prism degree mutual difference of the eye protector.

10. The measurement method of claim 9, further comprising: and judging the direction of the prism degree substrate of the eye protector according to the position relation between the intersection point of the two beams of refracted light passing through the second condenser lens and the imaging device.