A placido disc illumination and imaging device attachable to a slit lamp microscope
By designing a Placido disk illumination and imaging device that can be attached to a slit-lamp microscope, the problems of high cost and detection accuracy of existing equipment have been solved, realizing low-cost and accurate dry tear film examination, which is suitable for primary hospitals.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 66 VISION TECH CO LTD
- Filing Date
- 2026-05-14
- Publication Date
- 2026-06-19
AI Technical Summary
Existing tear film analysis equipment is independent and expensive, making it difficult to popularize in primary hospitals. It also cannot be shared with existing slit-lamp microscopes, resulting in increased equipment space occupation and costs. At the same time, the simple structure of the Placido disk makes optical axis alignment difficult, affecting detection accuracy and imaging quality.
Design a Placido disk illumination and imaging device that can be attached to a slit-lamp microscope, including a Placido disk body, a ring LED illumination assembly, and an optical axis adjustment mechanism. The device enables rapid installation and concentricity adjustment through magnetic connection and optical axis adjustment mechanism, and ensures light uniformity by combining a uniform light ring, thereby reducing costs and improving detection accuracy.
It enables low-cost, professional-grade dry tear film examination, reduces equipment purchase costs, improves detection repeatability and accuracy, is applicable to existing slit-lamp microscopes, and simplifies equipment space requirements.
Smart Images
Figure CN224369840U_ABST
Abstract
Description
Technical Field
[0001] This utility model mainly relates to the field of ophthalmic diagnostic technology, specifically to a Placido disk illumination and imaging device that can be attached to a slit-lamp microscope. Background Technology
[0002] Dry eye disease (DED) is a multifactorial chronic eye disease characterized by abnormalities in tear film and ocular surface, with a global prevalence of approximately 5% to 50%. Its core pathological manifestation is decreased tear film stability, primarily including two types: aqueous deprivation-deprivation (ADDE) and evaporative deprivation-deprivation (EDE). With increasing screen time, aging populations, and environmental factors, the incidence of dry eye disease is rising annually, becoming one of the most common chief complaints in ophthalmology clinics.
[0003] Tear break-up time (TBUT) is a core objective indicator for diagnosing dry eye. Traditional fluorescein TBUT (FBUT) requires the instillation of sodium fluorescein dye into the conjunctival sac, which is an invasive procedure that may disrupt the stability of the tear film, leading to test errors, and increasing patient discomfort and the risk of cross-infection.
[0004] Non-Invasive tear film breakup time (NIBUT) is based on the Placido disc principle and assesses tear film stability by observing the distortion time and position of concentric ring-shaped light spots projected onto the anterior tear film of the cornea. NIBUT has advantages such as being non-contact, repeatable, and providing objective quantification, and is one of the important examination methods recommended by current international dry eye diagnostic guidelines.
[0005] Currently, there are dedicated tear film analyzers on the market, such as the Oculus Keratograph 5M and TearLab, which can perform Placido disc tear film examination. However, these devices have the following shortcomings:
[0006] First, the equipment is independent and expensive (usually exceeding 200,000 RMB), making it difficult to popularize in primary hospitals and clinics. Second, it cannot be shared with existing slit-lamp microscopes, increasing the space occupied by departmental equipment and procurement costs. Third, the existing slit-lamp accessory Placido disk has a simple structure and lacks annular light uniformity control, resulting in poor image quality and inaccurate NIBUT calculations. Fourth, in existing solutions, it is difficult to align the Placido disk with the slit-lamp lamp light axis, and the off-center annular projection affects detection accuracy. Therefore, it is necessary to design a Placido disk accessory that can be quickly installed on a standard slit-lamp microscope to achieve professional-grade dry tear film examination function on existing slit-lamp equipment in a low-cost manner. Utility Model Content
[0007] 1. The technical problem to be solved by the utility model:
[0008] This invention provides a Placido disk illumination and imaging device that can be attached to a slit-lamp microscope to solve the technical problems existing in the background art.
[0009] 2. Technical Solution:
[0010] To achieve the above objectives, the technical solution of this utility model is as follows:
[0011] A Placido disk illumination and imaging device that can be attached to a slit-lamp microscope includes a Placido disk body, a lamp housing body, a ring LED illumination assembly, and an optical axis adjustment mechanism; the Placido disk body is detachably mounted on the front end of the lamp housing body.
[0012] The ring-shaped LED lighting assembly is installed at the rear end of the lamp housing body and is used to provide ring lighting to the Placido disk body;
[0013] The optical axis adjustment mechanism is connected to the lamp housing body and is used to adjust the concentricity of the device relative to the optical axis of the slit lamp.
[0014] The Placido disk body includes a shell, a disk core, and a light-uniforming ring. The inner wall of the disk core is provided with several concentric annular light-shielding strips, and light-transmitting gaps are formed between adjacent light-shielding strips. The light-uniforming ring is set in the optical path between the annular LED lighting component and the disk core to make the lighting light uniform.
[0015] A further improvement is that the Placido disc body and the lamp housing body are connected by a magnetic connection to achieve detachable installation.
[0016] A further improvement is that a magnetic bead is provided on the outer shell of the Placido disc body, and a lamp holder nut made of ferritic material is provided inside the lamp housing body, and the magnetic bead and the lamp holder nut are magnetically attracted to each other.
[0017] A further improvement is that the disc core is a frustum-shaped bowl-shaped shell, with its larger diameter end facing the patient's eye and its smaller diameter end facing the slit-lamp microscope.
[0018] A further improvement is that the annular light-shielding strip is made of a matte black paint layer or black film with a reflectivity of less than 5%.
[0019] A further improvement is that the number of concentric ring-shaped light-shielding strips is 8 to 16, and the outer diameter of both ends of the disk core is 24.5 to 49.5 mm.
[0020] A further improvement is that the cone angle of the disk core is 15.5°.
[0021] A further improvement is that the light-diffusing ring is made of aluminum alloy to eliminate the brightness unevenness of the LED point light source and ensure that the light illuminating the disk core is sufficiently diffused.
[0022] A further improvement is that the ring-shaped LED lighting assembly includes a lamp plate holder, a ring-shaped LED lamp plate, and a control switch; the LED lamp plate is mounted on the lamp plate holder, and the lamp plate holder is connected to the rear end of the lamp housing body.
[0023] A further improvement is that the optical axis adjustment mechanism includes a fixed base, a guide rail, a spring plunger, a support screw, and an adjustment shim;
[0024] The guide rail is installed in the fixed base, and the slider adapted to the guide rail is connected to the lamp housing body to realize the forward and backward movement adjustment of the lamp housing body.
[0025] The spring plunger is press-fitted into the fixed base and abuts against the slider to provide movement damping;
[0026] The support screw is installed at the bottom of the fixed base, and the adjusting shim is threadedly connected to the support screw to achieve device height adjustment.
[0027] 3. Beneficial effects:
[0028] Compared with the prior art, the technical solution provided by this utility model has the following advantages:
[0029] 1. Compared to large-scale, specialized dry eye examination equipment, it is cheaper and easier to promote.
[0030] 2. As an accessory to a regular slit lamp, it makes full use of the existing slit lamp equipment in medical institutions to achieve professional dry tear film examination at extremely low additional cost, effectively reducing equipment purchase expenditure.
[0031] 3. The ring-shaped LED, combined with the uniform light ring, ensures uniform brightness of the Placido ring projection, improving the repeatability of non-invasive tear film breakup time measurement. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0033] Figure 2 This utility model Figure 1 A schematic diagram of the split state structure;
[0034] Figure 3 This is a schematic diagram of the Placido disk body in disassembled state according to this utility model;
[0035] Figure 4 This is a schematic diagram of the disassembled lamp housing body of this utility model;
[0036] Figure 5 This is a schematic diagram of the disassembled state of the ring-shaped LED lighting component of this utility model;
[0037] Figure 6 This is a schematic diagram of the optical axis adjustment mechanism of this utility model in disassembled state.
[0038] Figure label:
[0039] 1-Placido disc body; 11-Outer shell; 12-Uniform light ring; 13-Disc core; 2-Lamp housing body; 21-Lamp housing; 22-Lamp holder nut; 23-Wire cover plate; 3-Ring LED lighting assembly; 31-Lamp board holder; 32-LED lamp board; 33-Switch; 4-Optical axis adjustment mechanism; 41-Fixed base; 42-Guide rail; 43-Spring plunger; 44-Support screw; 45-Adjusting shim; 46-Slider. Detailed Implementation
[0040] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the utility model will be more thorough and complete.
[0041] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," and "equipped with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0042] It should be noted that the structures not described in this utility model do not involve the design points and improvement directions of this utility model and all adopt existing technologies.
[0043] This embodiment provides a Placido disk illumination and imaging device that can be attached to a slit-lamp microscope, such as... Figure 1-2As shown, the device consists of a Placido disc body 1, a lamp housing body 2, a ring-shaped LED lighting component 3, and a light axis adjustment mechanism 4. The Placido disc body 1 is magnetically connected and fixed inside the hole of the lamp housing body 2, and the Placido disc body can be replaced as a whole. The ring-shaped LED lighting component is fixed to the rear end of the lamp housing body by screws. The slider 46 of the light axis adjustment mechanism 4 is connected to the lamp housing body 2 by screws, so as to realize the forward and backward movement of the lamp housing body 2.
[0044] like Figure 3 As shown, the Placido disk body consists of an outer shell 11, a light-diffusing ring 12, and a disk core 13. The disk core 13 is a conical bowl-shaped shell with a large-diameter end (facing the patient's eye) and a small-diameter end (facing the slit lamp). Several concentric ring-shaped light-shielding strips are provided on the inner wall of the disk core 13, forming light-transmitting gaps between adjacent light-shielding strips, creating a standard Placido disk pattern of alternating black and white concentric rings. The number of concentric rings is 8 to 16, with outer diameters of 24.5 to 49.5 mm at both ends and a cone angle of 15.5°. The light-shielding strips are made of matte black paint or a black film with a reflectivity of less than 5% to ensure high-contrast imaging. The light-diffusing ring 12 is made of aluminum alloy and is used to eliminate the brightness unevenness of the LED point light source, ensuring that the light illuminating the disk core is sufficiently diffused. That is, the light emitted by the ring-shaped LED lighting component 3 is first homogenized by the light-diffusing ring 12 before illuminating the disk core 13. Several magnetic beads are embedded on the right end face of the outer casing 11 for magnetic connection between the Placido disc body 1 and the lamp housing body 2.
[0045] like Figure 4 As shown, the lamp housing body consists of a lamp housing 21, a lamp holder nut 22, and a wire cover plate 23. The rear end of the lamp housing 21 is used to fix the ring-shaped LED lighting component. The lamp holder nut 22, made of ferrite, is fixed in the front hole by a threaded connection (the external thread of the lamp holder nut 22 directly engages with the threaded hole at the front end of the lamp housing 21). After the lamp holder nut 22 is assembled, the lamp housing can be magnetically connected to the Placido disk body 1. The wire cover plate 23 is a cover plate used for internal wiring of the lighting.
[0046] like Figure 5 As shown, the ring-shaped LED lighting assembly consists of a lamp plate holder 31, a ring-shaped LED lamp plate 32, and a switch 33. The LED lamp plate 32 is used to provide a uniform ring-shaped lighting source to the inside of the disk body, which is evenly distributed along the circumference. A switch 33 is provided on the LED lamp plate 32 to control the on and off of the LED light source. The LED lamp plate 32 is fixed to the lamp plate holder 31 by screws.
[0047] like Figure 6As shown, the optical axis adjustment mechanism consists of a fixed base 41, a guide rail 42, a spring plunger 43, a support screw 44, and an adjusting shim 45. The guide rail 42 is fixed to the fixed base by screws. The guide rail 42 includes a track fixed to the fixed base 41 and a slider 46 that cooperates with the track. The slider 46 is fixedly connected to the lamp housing body 2 to realize the back-and-forth movement of the lamp housing body 2. The spring plunger 43 is press-fitted into the mounting hole of the fixed base 41. The end of the spring plunger 43 is in elastic contact with the bottom surface of the slider 46 and always abuts against it. When the slider 46 slides back and forth along the guide rail 42, the spring plunger 43 generates contact friction by applying an upward elastic pressure to the bottom surface of the slider 46, thereby providing damping for the movement of the slider 46 and preventing the device from accidentally slipping under its own weight. The support screw 44 is connected to the fixed base 41 by threads (its own threads are directly screwed into the threaded hole of the fixed base 41). The adjusting shim 45 is connected to the support screw 44 by threads and is used to adjust the height of the entire device placed on the slit lamp. The entire device is adjusted in front and back and in height by slider 46 and adjusting shim 45 respectively, adjusting the concentricity of the light aperture of the Placido disk and the slit lamp axis to ensure that the center of the projection ring is aligned with the center of the cornea.
[0048] The above-described embodiments are merely illustrative of certain implementations of this utility model, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A Placido disc illumination and imaging device attachable to a slit lamp microscope, characterized in that, Includes the Placido disc body, lamp housing body, ring LED lighting assembly, and optical axis adjustment mechanism; The Placido disc body is detachably mounted on the front end of the lamp housing body; The ring-shaped LED lighting assembly is installed at the rear end of the lamp housing body and is used to provide ring lighting to the Placido disk body; The optical axis adjustment mechanism is connected to the lamp housing body and is used to adjust the concentricity of the device relative to the optical axis of the slit lamp. The Placido disk body includes a shell, a disk core, and a light-uniforming ring. The inner wall of the disk core is provided with several concentric annular light-shielding strips, and light-transmitting gaps are formed between adjacent light-shielding strips. The light-uniforming ring is set in the optical path between the annular LED lighting component and the disk core to make the lighting light uniform.
2. A Placido disc illumination and imaging device attachable to a slit lamp microscope according to claim 1, characterized in that The Placido disc body and the lamp housing body are connected by a magnetic connection to achieve detachable installation.
3. A Placido disc illumination and imaging device attachable to a slit lamp microscope according to claim 2, characterized in that The outer shell of the Placido disc is equipped with a magnetic bead, and the lamp holder nut made of ferritic material is provided inside the lamp housing. The magnetic bead and the lamp holder nut are magnetically attracted to each other.
4. The Placido disk illumination and imaging device for a slit-lamp microscope as described in claim 1, characterized in that, The disc core is a frustum-shaped bowl-shaped shell, with its larger diameter end facing the patient's eye and its smaller diameter end facing the slit-lamp microscope.
5. The Placido disk illumination and imaging device for a slit-lamp microscope as described in claim 1, characterized in that, The annular light-shielding strip is made of a matte black paint layer or black film with a reflectivity of less than 5%.
6. The Placido disk illumination and imaging device for a slit-lamp microscope as described in claim 1, characterized in that, The number of concentric ring-shaped light-shielding strips is 8 to 16, and the outer diameter of both ends of the disk core is 24.5 to 49.5 mm.
7. A Placido disk illumination and imaging device for attaching to a slit-lamp microscope according to claim 4, characterized in that, The cone angle of the disk core is 15.5°.
8. The Placido disk illumination and imaging device for a slit-lamp microscope as described in claim 1, characterized in that, The uniform light ring is made of aluminum alloy.
9. A Placido disk illumination and imaging device for a slit-lamp microscope as described in claim 1, characterized in that, The ring-shaped LED lighting assembly includes a lamp plate holder, a ring-shaped LED lamp plate, and a control switch; the LED lamp plate is mounted on the lamp plate holder, and the lamp plate holder is connected to the rear end of the lamp housing body.
10. A Placido disk illumination and imaging device for attaching to a slit-lamp microscope according to claim 1, characterized in that, The optical axis adjustment mechanism includes a fixed base, a guide rail, a spring plunger, a support screw, and an adjustment shim; The guide rail is installed in the fixed base, and the slider adapted to the guide rail is connected to the lamp housing body to realize the forward and backward movement adjustment of the lamp housing body. The spring plunger is press-fitted into the fixed base and abuts against the slider to provide movement damping; The support screw is installed at the bottom of the fixed base, and the adjusting shim is threadedly connected to the support screw to achieve device height adjustment.