CN2840091Y - Optical system for transmission type eyesight detecting instrument - Google Patents

Abstract

The utility model relates to an optical system, in particular to an optical system of a detector for measuring the retinal potential vision of eyes with different diopters. This new model provides the optical structure and optical path design of the eye vision function tester for cataract patients; the design and related parameters of each optical component are given, and its characteristic is that it adopts a transmissive vision resolution board to make the imaging beam entering the pupil It is thin enough and has enough light energy to form an image on the retina through the tiny gap in the cloudy lens of cataract patients. The potential diopter of the patient can be measured by moving the transmission vision resolution board to adjust the focus, and the visual acuity can be identified by looking at the tested eye The level of visual resolution corresponding to the opening direction of the smallest character E in the resolution board is used to calibrate the visual acuity. Through the pre-operative detection of cataract patients, the instrument can accurately predict the visual acuity level achieved after replacement of intraocular lens surgery, which is very necessary and practical for cataract patients and ophthalmologists.

Description

Optical system of transmission vision tester

technical field

The utility model relates to an optical system, in particular to an optical system of a detector for measuring retinal latent vision of eyes with different diopters, which is used for a special vision (potential vision) detector before cataract patients operate.

Background technique

For cataract eye disease patients, we researched and designed the optical system of the transmission vision tester. Cataract is a common eye disease that seriously affects vision. It is known that millions of cataract patients undergo intraocular lens replacement surgery every year. One of the most important issues for doctors and patients is the visual performance after replacement of intraocular lens surgery. What level is reached, that is, to exclude the influence of cataract (lens) and to detect the potential visual ability of other factors (including: cornea, retina). Usually the visual acuity testing system and method for normal eyes is that the visual acuity chart with diffuse reflection white background and black mark is used for testing, the illuminance should be 200-300 lux, the test distance is 5m, and the word mark with a visual angle of 1 point corresponds to 5.0 (for visual acuity chart). The imaging light beam of the eye chart can fill the entire pupil of the eye of the subject and image it on the retina. For cataract patients, most of the eye lens is opaque and opaque, only the cracks or small holes in it can transmit light, and some patients have light-transmitting cracks or small holes≤0.1mm, that is to say, only these cracks or small holes can There is not enough light passing through and forming an image on the retina to cause the visual cells to respond, and the image is blurred. Usually, the diameter of the pupil of the human eye is (2-8) mm, and the entire pupil is filled with light during the test, and the light energy involved in retinal imaging is (400-1600) times that of cataract patients, so the conventional vision detection system cannot Measure the true potential vision of cataract patients. There may be many factors that affect vision. If it is not possible to predict other problems other than cataract lenses that affect visual function, such as retinopathy, although the replacement of intraocular lens surgery is performed, the visual effect cannot be improved, and even disputes between patients and doctors may arise. In order to enable doctors and patients to accurately predict postoperative visual acuity (potential visual acuity) before surgery, a special preoperative visual acuity (potential visual acuity) detection system and detection method for cataract patients are needed. There are no identical patents and literature reports at home and abroad.

The optical system of this transmissive vision tester adopts a transmissive vision resolution plate, and the imaging beam entering the pupil is thin enough and has enough light energy, so that it can image on the retina through the tiny gap in the cloudy lens. The diopter of the patient's diopter between -7D and +12D can be measured by moving and focusing the transmissive vision resolution board. The diopter corresponding to the opening direction of the smallest character E in the vision resolution board can be recognized by the tested eye. Level 1 visual resolution calibration visual acuity. This makes it possible to measure the visual acuity of cataract patients. Through the detection of this instrument, the visual acuity level achieved after surgery can be predicted, and it can also be determined whether it is pure crystal disease or other eye diseases, helping doctors to make a correct diagnosis. The system is feasible and reliable through experiments.

Contents of the invention

The utility model specifically provides the overall optical structure design and optical path of the practical "transmissive vision tester"; provides the design and related parameters of each optical component; and the detection method of the instrument. This instrument is an eye potential visual function tester mainly for cataract patients. It is characterized in that it adopts a transmissive vision resolution board and makes the imaging beam entering the pupil of the eye thin enough and has enough light energy, so that it can pass through the cloud of cataract patients. The tiny gaps in the lens are imaged on the retina, and the diopter of the patient's diopter between -7D and +12D can be measured by moving the transmission vision resolution board to focus, and the smallest in the vision resolution board can be identified through the tested eye. The grade of visual resolution corresponding to the opening direction of the character E is used to calibrate the visual acuity. Through the preoperative detection of cataract patients by this instrument, it can be more accurately predicted the visual acuity level achieved after replacement of intraocular lens surgery.

The technical scheme of the utility model: the optical system of the transmissive vision detector, the white light emitted by the light source is focused on the small filter hole through the condenser lens, and the light beam filtered by the small hole is reflected twice by the triangular reflective prism, and then passes through the quasi- The straight lens produces quasi-parallel light, and the quasi-parallel light irradiates the transmissive vision resolution board. The transmissive vision resolution board is imaged by the imaging lens, and the eye viewpoint Eye watches the image of the vision resolution board through the triangular reflective prism and the triangular reflective prism. Can identify the opening direction of the smallest character E in the vision resolution board to detect vision; it is characterized in that: the light beam emitted from the filtered small hole passes through the collimator lens, the transmission vision resolution board and the imaging lens, and converges at the Eye point to a diameter ≤ The imaging beam of 0.1mm is equivalent to the filter pinhole forming a reduced image point at the Eye point.

The basic principle of the testing technology of the optical system of the transmission vision tester:

The light source is converged by the condenser, and then filtered by the filter hole, which is equivalent to a point light source. The point light source generates a collimated beam through the collimator lens and illuminates the transmissive vision resolution board. The imaging light beam of the transmissive vision resolution board converges to a very small light spot at the Eye behind the imaging lens, so that the imaging light beam can pass through the narrow hole of the cloudy cataract crystal of the eye to form an image on the retina. When measuring the patient's vision, let the patient's pupil coincide with the Eye point to watch the vision resolution board. Since the diopter of the patient's eyes may be different, in order to enable the instrument to accurately measure the retinal latent vision of eyes with different diopters, it is necessary to adjust the position of the vision board so that the vision board can just be imaged on the retina. We have designed a movable vision board. , eyes with different diopters can adjust the focus by adjusting the distance from the vision board to the imaging lens (even if the patient under test can see the vision board clearly), the geometrical optical conversion relationship between the position of the vision board and the eye diopter, in The forward and backward movement position of the vision board of the instrument is calibrated and converted to the corresponding diopter, and the eye diopter and the position of the vision board when the vision board can be clearly seen are in one-to-one correspondence. The adjustment of the position of the vision board is equivalent to the selection of "inserts" of different diopters when performing vision testing when wearing glasses. Then the eye to be tested looks carefully, and can recognize the opening direction of the characters E at all levels in the vision resolution board, and can recognize the level of visual resolution corresponding to the opening direction of the smallest character E, that is, the eye under test eyesight.

Beneficial effects of the utility model: the instrument can detect cataract patients before operation, and can accurately predict the visual acuity level achieved after replacement of intraocular lens surgery. It is very necessary and practical for cataract patients and ophthalmologists, and it has been proved by experiments. practicality and reliability.

Description of drawings

Accompanying drawing 1 is the optical system structural diagram of the transmissive visual acuity tester

Accompanying drawing 2 is the optical path diagram of the transmissive vision tester

Attached Figure 3 Schematic Diagram of Transmissive Vision Resolution Board

In the figure: 1. Light source 2. Concentrating lens 3. Filter pinhole 4. Triangular reflective prism 5. Collimating lens 6. Vision resolution board 7. Imaging lens 8. Triangular reflective prism 9. Triangular reflective prism 10. Eye

Detailed ways

Below in conjunction with accompanying drawing the embodiment of the present utility model is further described:

The optical system of the transmissive vision tester, the white light emitted by the light source 1 is focused on the filter pinhole 3 by the condenser lens 2, and the beam filtered by the pinhole is reflected twice by the triangular reflective prism 4, and then passes through the collimator lens 5 Generate quasi-parallel light, the quasi-parallel light irradiates the transmissive vision resolution board 6, the transmissive vision resolution board is imaged by the imaging lens 7, and the eye viewpoint Eye10 watches the visual resolution board through the triangular reflective prism 9 and triangular reflective prism 8 It can identify the opening direction of the smallest character E in the vision resolution board to detect the eyesight; its characteristic is that the light beam emitted from the filtered pinhole passes through the collimator lens, the transmissive vision resolution board and the imaging lens, and converges at the Eye point as The imaging beam with a diameter of ≤0.1mm is equivalent to a small filter hole forming a reduced image point at the Eye point.

The filter aperture (3) is a circular light hole, and the diameter is a light barrier of 0.1 to 0.2 mm.

The triangular reflective prism 8 and the triangular reflective prism 9 change the light path direction to determine the viewing orientation of the tested eye.

The distance d7 between the transmissive vision resolution board 6 and the imaging lens 7 is variable from zero to 2 times the focal length of the imaging lens, and the position of the resolution board is adjusted so that the tested eye can see the image of the vision board clearly; According to the conversion relationship between the position of the vision board, the optical system parameters and the eye diopter, the diopter corresponding to each position is calibrated within the movement range of the vision board of the instrument, that is, the diopter.

Vision resolution plate 6 is a transmissive vision resolution plate made of characters E of different sizes and sizes on a glass substrate, which is completely black and opaque, with a bright bottom and light transmission. Composed of 12 levels of resolution standards, the opening orientation of E in each level of characters is arranged differently, and the design of each level of character size and stroke thickness is based on the international standard logarithmic eye chart and the imaging magnification of the optical system. It is determined by calculation that the visual resolution corresponding to the level where the opening of the smallest E of the level character can be distinguished by the tested eye is the visual acuity.

The light source 1 adopts a white light emitting diode or an incandescent lamp as a quasi-point light source, and the filter hole 3 is made of a circular light-through hole on a glass substrate through microfabrication, photolithography, or micromachining on a metal sheet. Both the lens 5 and the imaging lens 7 are positive lenses.

The design of each optical component of the structural parameters of the system:

The structural parameters of the optical system are shown in Figure 1: d1 is the distance from the light source to the condenser lens 2, d2 is the distance from the filter hole 3 to the condenser lens 2, and d3 is the first reflection surface from the filter hole 3 to the triangular reflective prism 4 Optical axis distance, d4 is the distance from the optical axis of the first reflective surface of the triangular reflective prism 4 to the optical axis distance of the second reflective surface, d5 is the distance from the second reflective surface of the triangular reflective prism to the collimator lens 5, and d6 is The distance from the collimator lens 5 to the resolution plate 6, d7 is the distance (variable) from the resolution plate 6 to the imaging lens 7, d8 is the distance from the imaging lens 7 to the reflective surface optical axis of the triangular reflector 8, and d9 is The distance from the reflective surface of the triangular reflective prism 8 to the optical axis of the reflective surface of the triangular reflective prism 9, d10 is the distance from the reflective surface of the triangular reflective mirror 9 to the pupil of the detected eye.

Wherein the main optical components: the white light source 1 is a white light LED (light emitting diode) or an incandescent lamp quasi-point light source; the filter aperture 3 is a light barrier with a circular light hole diameter of 0.1 to 0.2mm, which can pass microscopic, Photolithography process or micro-machining on metal sheets; transmissive vision resolution plate 6 as shown in Figure 3, it is made on a diameter of about 15mm garden-shaped glass substrate by processes such as miniature, photolithography, etc. Characters are full Transparent, the back is an opaque transmissive vision resolution board, which is composed of characters E with 12 levels of resolution standards of different sizes, and the design and calculation of the size of each level of characters and the thickness of strokes are based on international standards. Based on the digital eye chart, the angle of view of 1 minute is calibrated as 1.0, and then the zoom design is carried out according to the common ratio of the sub-marks of the logarithmic eye chart and the imaging magnification of the optical system; the condenser lens 2 is a positive lens with a focal length of 25 to 35mm , the collimating lens 5 is a positive lens with a focal length of 300 to 400 mm, and the imaging lens 7 is a positive lens with a focal length of 90 to 100 mm.

The detection method is that the pupil of the tested human eye is aligned with the Eye point and fine-tuned, so that the converging thin light beam passes through the tiny gap in the lens of the cataract patient to form an image on the retina, and the image formed by the resolution plate 6 through the imaging lens 7 is observed. Then adjust the position of the resolution board 6 until the resolution board 6 is seen clearly, read out the diopter marked at the corresponding position, and then watch carefully, the opening direction of the characters E at all levels in the vision resolution board can be identified, and the The level of visual resolution corresponding to the opening direction of the smallest character E is the visual acuity of the tested eye.

Example

System structural parameters and design examples of optical components:

The specific parameters of the system structure and the design of each optical component are as follows:

The focal length f1=30mm of condenser lens 2, the focal length f2=370mm of collimating lens 5, the focal length f3=95mm of imaging lens 7, the distance of filter pinhole 3 to collimating lens 5 is 165mm, collimating lens 5 to imaging lens The distance of 7 is 215mm, and the aperture of filter aperture 3 is d=0.2mm.

Calculated by geometric optics theory:

The filter pinhole 3 also forms a reduced image at 117mm behind the imaging lens 7, and the image point size d'=0.082mm, that is to say, the imaging beam converges to 0.082mm at this place, and the eye pupil can be aligned with the Eye point. Make the imaging thin light beam pass through the tiny gap in the cloudy lens of the cataract patient, and the vision resolution board 6 forms an image on the retina to detect the vision.

In the case of the above optical system, calculate the position of the vision board corresponding to different diopters of the eye, and calculate the change of the position of the vision board when the diopter D changes from -7 to +12, as shown in Table 1:

Diopter D -7 -6 -5 -4 -3

Vision board object distance d7 -20.53 -32.76 -44.39 -55.48 -66.04

Diopter D -2 -1 -1 0 +1 +2

Vision board object distance d7 -76.13 -85.78 -95 -103.83 -112.3

Diopter D +3 +4 +5 +6 +7

Vision board object distance d7 -120.42 -128.22 -135.72 -142.92 -149.86

Diopter D +8 +9 +10 +11 +12

Vision board object distance d7 -156.54 -162.97 -169.18 -175.17 -180.96

Table 1 Data of relationship between object distance and diopter of vision board

The vision board object distance d7 in the table is the distance from the above-mentioned resolution board 6 to the imaging lens 7; the unit of diopter D is 1 diopter, which is equivalent to 100 degrees of glasses, and the positive and negative signs indicate hyperopia and myopia.

Imaging relationship and visual effects at different positions of vision board

It can be proved by theoretical calculations and experiments that no matter whether the vision board is located within the focal length of the imaging lens 7 or outside the focal length, the positive and negative images on the retina are the same, and the size of the image does not change much. The reason is that the position of the vision board changes within a range from a position close to the imaging lens 7 to a position twice the focal length. When the vision board was within the focal length of the imaging lens 7, the image formed by the vision board through the imaging lens 7 was a virtual image that was enlarged and upright, and the position of the image was in front of the eyes; as the vision board was away from the imaging lens 7, when moving to the focal point, Imaging at infinity; when the vision plate was outside the focal point of the imaging lens 7, the vision plate formed a real image by the imaging lens 7 at this moment, and the position of the image was behind the eyes, the object distance was positive for the eyes, and the The equivalent focal length is positive, so the image formed on the retina through the eyes is the same as the image formed by the vision board through the magnifying glass. When the vision board continues to move away from the imaging lens 7, the imaging position will be closer and closer to the eyes accordingly. When the vision board moves from within the focal length of the imaging lens 7 to 2 times the focal length, the diopter corresponding to the eye to be tested increases monotonically. Therefore, when the tested eye is in a relaxed state and can see a clear image of the vision plate at a certain distance, the diopter of the tested eye corresponding to the distance can be calculated. When observing with the eyes, the uprightness of the vision board seen is constant throughout the range of motion. And the size change of the seen image is also very small. Does not affect the measurement of vision at all. It can meet the needs of the system for testing patients with different diopters.

Claims (6)

1. An optical system of a transmissive vision tester, the white light sent by the light source (1) is focused on the filter aperture (3) through the condenser lens (2), and the light beam filtered through the aperture is passed by the triangular reflective prism (4) ) secondary reflection and return, and then produce quasi-parallel light through the collimating lens (5), and the quasi-parallel light illuminates the transmissive vision resolution plate (6), and the transmissive vision resolution plate is imaged by the imaging lens (7), and the eye point of view Eye (10) watches the picture of this eyesight resolution plate by triangular reflective prism (9) and triangular reflective prism (8), and can recognize the opening direction of the smallest character E in the vision resolution plate to detect eyesight; it is characterized in that: filtering The light beam emitted from the pinhole passes through the collimator lens, the transmissive vision resolution plate and the imaging lens, and converges into an imaging beam with a diameter of ≤0.1mm at the Eye point, which is equivalent to filtering the pinhole into a reduced image point at the Eye point. 2. The optical system of the transmissive vision tester according to claim 1, characterized in that: the filter aperture (3) is a circular light aperture, and the diameter of the aperture is a light barrier of 0.1 to 0.2 mm. 3. The optical system of the transmissive vision tester according to claim 1, characterized in that: the triangular reflective prism (8) and the triangular reflective prism (9) change the direction of the light path to determine the viewing orientation of the eye to be tested. 4. The optical system of the transmissive vision tester according to claim 1, characterized in that: the distance d7 between the transmissive vision resolution plate (6) and the imaging lens (7) is from zero to the focal length of twice the imaging lens variable between. 5. The optical system of the transmissive visual acuity tester according to claim 1, characterized in that: the visual acuity resolution board (6) is to make the character E on the glass substrate by miniature and photolithography process to be completely black, impermeable Light, the background is a bright bottom, light-transmitting transmissive vision resolution board, it consists of 12 levels of resolution standards composed of characters E of different sizes, and the opening orientation of E in each level of characters is arranged differently. 6. The optical system of the transmissive vision tester according to claim 1, characterized in that: the light source (1) adopts a white light emitting diode or an incandescent lamp as a point light source, and the filter aperture (3) is formed on the glass substrate by microscopic, A photolithographic process or micro-machining on a metal sheet is used to form a circular light-through aperture, and the condenser lens (2), the collimator lens (5) and the imaging lens (7) are all positive lenses.

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