FIELD

Embodiments of this invention generally relate to face shields that are worn in combination with loupes and headlights. In particular, the face shield has a rim which allows for frontal clearance adjustment, which can be used with a standard or an anti-reflective visor for improved optical performance.

BACKGROUND

Given the COVID-19 pandemic, it is now required or highly recommended in a number of countries that medical professionals wear face shields. Current face shields, however, do not meet the specific needs of medical professionals (MP).

The clearest example is that there is insufficient frontal clearance on face shields for medical professionals that wear loupes and lights, such as dentists, hygienists and surgeons. On a majority of face shields, the visor is a fixed distance away from the face, allowing enough room for the nose, but no more.

Certain face shields have adjustable frontal clearance, however, the visor can only be set to a few predefined frontal positions. This is problematic as each MP’s loupe and light setup is varied. Thus, the ideal frontal clearance for each MP is different. If a MP had full control over the frontal clearance, they could adjust the visor to be directly in front of their light, which would reduce perceptible glare.

Furthermore, even face shields with adjustable front clearance do not have enough frontal clearance to accommodate loupes with very large magnification. Also, when adjusted forward, the visor does not provide sufficient lateral protection for the face.

Another problem with available face shields is light reflection. The source of light could be from the MP’s headlight or bright lights in their office. This light reflects off the visor and into the MP’s eyes. This creates distracting highlights on the visor, impeding vision, and can cause eye strain. Further, because the visor on a MP’s face shield is adjusted further forward than normal, a greater area of the visor and the distracting highlights are in the user’s field of vision. Another issue with available face shields is cleanability. A requirement for medical face shields is that they are cleaned/disinfected between patients. Available face shields with adjustable front clearance, use intricate, multi-component mechanisms that have many hard-to-clean nooks and crannies.

SUMMARY

Generally, embodiments of the medical face shield provide frontal and lateral protection for the face from splashes of liquid. Embodiments can provide this frontal and lateral protection by a visor which can act as a physical barrier between the liquid and a users’ face. The face shield has features which allow it to achieve its primary function while accommodating the user’s loupes and lights, and maintaining high optical clarity.

Embodiments of the medical face shield comprise three primary components: a head harness for securing the face shield on a wearer’s head, a rim, operatively connected to the head harness; and a visor secured (temporarily or otherwise) to the rim.

In a broad aspect of the invention, a medical face shield comprises a head harness for securing the medical face shield onto a head of a user, and a rim mounted to the head harness and adapted to removably secure a visor thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of an embodiment of the present invention, illustrating a head harness, rim and a visor;

Figure 2 is a top plan view of the embodiment in accordance to Fig. 1 , illustrating the head harness, rim and visor; and

Figure 3 is a perspective view of a securing mechanism for securing the rim onto the harness in accordance to Fig. 1.

Figure 4 is a perspective view of the rim and visor in accordance to Fig. 1 ;

Figure 5 is a perspective view of an embodiment of the invention illustrating an alternate rim having a plurality of openings; Figure 6 is a perspective view of an embodiment of the invention illustrating an alternate embodiment of a rim having two rows of a plurality of openings;

Figure 7 is a perspective view of an embodiment of the invention illustrating another alternate embodiment of a rim having two elongates slots; and Figure 8 is a perspective view of an embodiment of the invention illustrating a semi-circular rim.

DETAILED DESCRIPTION

With reference to Figs. 1 and 2, in a broad aspect, the medical face shield comprises three primary components: a head harness 1 , a rim 2 and a visor 3. As shown, the head harness 1 further comprises a top adjustable head strap 4, an adjustable back head strap and a front band 6. The combination of the top adjustable head strap 4, the adjustable back head strap and the front band allow the medical face shield to be positioned about a forehead of a person and temporarily secured about a circumference of the head of the person or user of the face shield. Skilled persons in the art would understand that the top adjustable head strap 4 supports the weight of the medical face shield, while the adjustable back strap can be adjusted to fit an individual person wearing the face shield.

In embodiments, the adjustable back head strap can further comprise a means for temporarily securing or tightening the medical face shield about the head of the person. As shown, and in one embodiment, the means for temporarily securing the medical face shield can be a ratcheting system 5. In other embodiments, the means for temporarily securing the medical face shield can be a simple buckle with a corresponding strap having holes to accept the buckle. This type of securing system is shown as part of the top adjustable head strap 4 in Fig. 1 .

In embodiments, the top adjustable top head strap can support a weight of the face shield on top of the user’s head and reduce a compression force required on the side of the user’s head to secure the face shield to the user’s head.

In embodiments, the top adjustable head strap can be made from a rigid polymer. In other embodiments, the top adjustable head strap can be made from a soft fabric material, which can be advantageous because a soft fabric top strap can deform during storage to save space.

In an embodiment, the face shield may not have an adjustable top head strap.

The adjustable back head strap comprising the ratcheting system 5 is advantageous as it prevents users from experiencing an overwhelming force that can cause headaches for the users. For example, an elastic headband can also be used to secure the head harness 1 to the head of the user, but an elastic band can cause overwhelming force onto the head which causes headaches and makes the shield uncomfortable to use.

The adjustable ratcheting system on the back head strap allows for circumferential adjustment and can adapt to various sizes or circumferences of heads, depending on the user.

In embodiments, the front band 6 can further comprise padding or other material that can be adapted to provide comfort and/or wick away moisture or perspiration on the forehead of the person. In embodiments, this front band 6 can be removable to allow for cleaning and disinfecting.

With reference to Fig. 2, the rim 2 can be a single integral piece that is operatively connected to the head harness 1 . The single, integral rim 2 provides structural rigidity and stiffness and can better support the visor 3 on the head harness 1 . As shown, and in embodiments, the rim 2 can be operatively attached to the head harness 1 at opposing points 55, 56 on the head harness 1 by a pair of attachment means 54 that allows controlled axial rotation of the rim 2 about the head harness 1 . In embodiments, each of the pair of attachment means 54 can include a bracket 57, such as an L-shaped bracket, and a spacer 7 for interfacing with the rim 2. Securing means, such as screws and nuts 8 can be used to tighten and otherwise secure the rim 2 to the attachment means 54. A person skilled in the art would understand that a screw can extend through the bracket 57, through the spacer 7 and the rim 2. At a distal end of the screw, a nut 8 can be used to secure the bracket 57, spacer 7 and the rim 2 operatively together. In embodiments, and as shown, the screw can be inserted to extend through the attachment means 54, and the rim 2 from an inside portion of the head harness 1 , and the nut 8 to secure everything can be positioned on an outside of the head harness 1 .

The bracket 57 rotatably secures the rim 2 to the head harness 1 at opposing points 55, 56 and the spacer 7 positions or otherwise spaces the rim 2 away from the head harness 1 and the head of the user wearing the face shield. Rotatably attached to the bracket 57 is spacer 7, which serves to operatively secure the rim 2 to the head harness 1 .

The spacing away of the rim 2, and ultimately the visor 3, from the head harness 1 and the user’s head, provides sufficient spacing to create an air flow path between the head of the person and the visor 3. This air flow path allows sufficient air to flow therethrough and prevent moisture and condensation from collecting or pooling on an inside surface of the visor 3, which can lead to fogging and reduced visibility.

With reference to Figs. 2 and 3, the spacers 7 can be positioned at opposite points of the head harness 1 , and each spacer 7 can have a channel 9 which aligns and constrains the rim 2 therein. The spacers 7 can have a hard-stop 10 on an outer facing surface 11 thereof and a dial feature which can enclose a nut 12.

As shown, the rim 2 is connected to the head harness 1 by the attachment means 54 via the bracket 57 and spacers 7. To secure the rim 2 to the head harness 1 , the rim 2 can be placed into the angled channel 9 on the spacer 7. On each side of the face shield, a screw (not shown) can be positioned through the bracket 57 attached to the head harness 1 , the spacer 7 and the rim 2. A nut 8 is adapted to accept each screw therethrough and can be rotatably tightened to secure the rim 2 in place. As the rim 2 is pushed into the channel 9 of each spacer 7 by the rotation of the nut 8, the rim 2 is positioned and constrained therein. Continued tightening of the nut 8 compresses the rim 2 within the channel 9 of the spacer 7. After a threshold amount of compression is applied onto the rim 2, a base of the nut 8 will catch a hardstop 10, preventing further tightening of the nut 8 and preventing physical damage from occurring.

In embodiments, simple tightening or loosening a single nut 8 allows the users to quickly set up and adjust the position/angle of the visor 3.

In an embodiment, for when the rim 2 is freely rotatable, the rim 2 can be limited in rotation, and be prevented from rotating past certain pre-determined angles. A threshold or limiting angle could be set at the point where the attached visor makes an appropriate angle relative to the face.

In order to fix the rotation of the rim 2 relative the head harness 1 , the rim 2 can be supported at, at least, one point that is not on an axis of rotation of the rim 2, and where surface contact forces, such as friction, can be created to oppose rotation of the rim 2. In embodiments, there can be multiple points of contacts, or surface to surface contact, to distribute frictional forces, decrease contact surface stress and increase contact stiffness.

In an embodiment, the rim 2 has two opposing sides, and both of the opposing sides can have their rotation constrained by the same feature. In an embodiment, two pins can be used, per side. In another embodiment, 1 pin and 1 surface which supports the bottom of the rim can be used, per side. In another embodiment, 1 surface which supports a top of the rim 2, and 1 surface which supports a bottom of the rim 2 can be used, per side. Having surfaces constrain both the top and bottom surface of the rim 2 can constrain the rotational motion in both directions, while supporting only the bottom would limit just the rotational motion in one direction.

In a preferred embodiment, the attachment means 54 can further comprise a feature which can prevent the nut 8 from being tightened too much, to the point the rim 2 can no longer rotate. In an embodiment, there can be a locking mechanism which can engage a surface of the nut 8 which faces towards the head harness 1 . As the nut 8 is tightened and that surface moves closer to the head harness 1 , the nut 8 can be prevented from rotating further, yet, the rim 2 can both be easily tilted by a single hand and held to a fixed angle, supporting its weight.

As shown, the rim 2 can rotate about the head of the user relative to the head harness 1 . This permits the user to make slight adjustments to the positioning of the visor 3 to ensure that the visor 3 is providing sufficient protection and coverage from below the rim 2 and also from above the rim 2. The rotational ability of the rim 2 also allows the user to completely flip or position the visor 3 out of the user’s field of view when desired.

In an embodiment, the rim 2 can freely rotate about the user’s head, under the force of gravity. In another embodiment, the nut 8 can be tightened so that the rim 2 does not move freely under the weight of gravity, but rather can be manually adjusted by the user to certain viewing angles and hold those viewing angles until further adjustment is required.

In an alternate embodiment, the face shield can have a cover 12 over nuts 8. In use, the user can grip the cover, when tilting or adjusting the viewing angle of the visor, instead of rotating the nuts 8. The cover prevents accidental unscrewing of the nuts 8 from the screws that secure the rim 2 to the attachment means 54 and the head harness 1 . In embodiments, the cover can be detailed such that it can be textured to increase grip for fingers, similar to the nuts 8.

With reference to Figs. 1 to 3, in embodiments, the rim 2 of the medical face shield has the ability to move laterally forward or backwards, relative to the head harness 1 . In contradistinction, face shields used in the industry have visors that are positioned at a fixed distance from the user. This lateral adjustment or movement allows users to increase or decrease a frontal clearance of the visor 3 to accommodate loupes, lights or other items which can often be worn. For example, a user can adjust the frontal clearance to position the visor 3 to be just in front of a light that the user is wearing for a particular procedure. This decreases the distance the light travels before reaching the visor, reducing the amount it spreads and reducing the amount of light reflected back into the user’s eye.

With reference to Figs. 2 and 3, in embodiments, and as shown, the rim 2 can comprise a U-shaped rim having a frontal piece 51 in between two opposing sides 52,53. As shown, the two opposing sides 52, 53 can be positioned perpendicular to the frontal piece 51 , thereby forming the U-shaped profile thereof.

In embodiments, each of the two opposing sides 52, 53 are adapted to be inserted into the channel 9 in each of the spacers 7. In embodiments, each of the opposing sides 52, 53 can be frictionally fit into the channel 9, providing a snug or tight fit, preventing free movement of the opposing sides 52, 53 within the spacer 7. In such an embodiment, the rim 2 is positioned so that the visor 3 is at a constant and fixed distance away from the user’s head.

In preferred embodiments, the opposing sides 52, 53 can be adapted to freely move within the channel 9, allowing for the lateral or frontal adjustment of the rim relative to the head harness 1 . In an embodiment, the opposing sides 52, 53 can further comprise at least one opening 59 for accepting a screw (not shown) to freely pass therethrough and engage the nut 8 for securing the rim 2 to the head harness 1 . In embodiments, the at least one opening can be a plurality of openings positioned and spaced along the rim 2 adjacent a distal end 58 of each of the opposing sides 52, 53. A user can select an appropriate opening and position the rim 2 to be secured to the attachment means 54 for laterally positioning the rim 2 relative to the head harness 1 .

In embodiments, the at least one opening can be elongated slots 18 positioned adjacent the distal end 58 of each of the opposing sides 52, 53, which allows a screw (not shown) to freely pass therethrough when securing the rim 2 to the attachment means 54. The elongated slots 18 permit longitudinal travel of the rim 2 relative to the screw and the head harness 1 , thus permitting lateral or frontal adjustment or positioning of the visor 3 secured to the rim 2 without having to fully remove the rim 2 from the head harness 1 . In an embodiment, the user can simply loosen the nuts 8 securing the rim 2 to the head harness 1 , reposition the rim 2 by manually moving the rim 2 longitudinally therealong and within the channel 9, adjusting the frontal clearance until an optimum frontal clearance is achieved. Then the user can simply tighten the nuts 8 to secure the rim 2 in place and to maintain this desired frontal clearance.

In an embodiment, the rim 2 can both freely rotate and travel longitudinal relative to head harness under the force of gravity.

In embodiments, there is a chamfer, such as a 45° chamfer on an inner surface 19 of the rim 2 and the opposing sides 52, 53, which allows the rim 2 to selflocate within each of the channels 9 when tightening the nut 8 to secure the rim 2 to the head harness.

In embodiments, in order to provide sufficient protection of the user’s face from the side, a length of the elongate slots 18 can be limited. In other embodiments, instead of limiting the range of lateral movement of the rim 2, the opposing sides 52, 53 of the rim 2 can be extended to allow an increase in length of the elongated slots 18.

The Applicant notes that having an elongated slot of about 8 cm long provides sufficient frontal clearance for most users to allow use of most, if not all, commercially available loupes, and loupes with light attachments. In such embodiments, the rim 2 provides sufficient frontal clearance to minimize fogging of the visor 3 and decrease feelings of claustrophobia.

In an alternate embodiment and in an embodiment shown in Fig. 5, the rim 2 can comprise at least one opening 59, such as a plurality of openings spaced laterally along each of the opposing side 52, 53 adjacent the distal end 58 of the rim 2. In such embodiments, the user can adjust the frontal clearance by removing the nuts 8 and the rim 2 from the attachment means 54, repositioning the rim 2 such that the screw extends through one of the plurality of openings and then reinstalling the nuts 8. Such embodiments are disadvantageous as compared to an elongated slot as described above because a plurality of openings does not provide the finer lateral adjustment that an elongated slot will provide.

Fig. 6 shows an alternate embodiment of the rim 2, wherein the plurality of openings can be two rows of openings, allowing finer adjustment of the frontal clearance of the rim 2. Such an embodiment is also advantage because having multiple rows of openings also allows for vertical positioning of the rim relative to the head harness.

Fig. 7 illustrates another embodiment of the rim 2 having two elongated slots. One of the elongated slots can be used to permit longitudinal travel of the rim therealong for adjusting the frontal clearance, while the second elongated slot can be used to function as a guide and provide additional rigidity and security of the adjustment mechanism.

The medical face shield provides frontal and lateral protection for the face of a user from splashes of liquid. This protection can be achieved by the visor 3 which acts as a physical barrier between the liquid and the user’s face. The face shield has features which allow it to achieve its primary function while accommodating for the user’s loupes and lights, and maintaining high optical clarity.

With reference to Figs. 1 and 2, the visor 3 can be a thin sheet of transparent plastic or other transparent polymeric material. The visor 3 can be secured to the rim 2 of the face shield by being wrapped around the rim 2 along an outside surface 16 of the rim 2. By wrapping around the rim 2, the visor 3 can provide frontal protection. Lateral or side protection of the user’s face can be had by extending a length of the visor 3 sufficiently along the opposing sides 52,53 of the rim 2 to a point past the user’s eye.

Further, in an embodiment, and as shown, a top of the visor 3 can extend a sufficient distance 21 above the rim 2 to provide additional protection of a forehead of the user from splashes of liquid coming over the top of the face shield. This is advantageous over face shields that do not have this extension because when such face shields are extended laterally, a gap can form between the visor and the forehead. Embodiments of the invention maintains effectiveness by extending the visor 3 a sufficient distance 21 above the rim 2 to protect splashes from entering the gap, present in the default visor position, or created when the visor is moved laterally forward.

In embodiments, the visor 3 may not extend above the rim 2 to protect against splashes of liquid entering through the gap created when the visor 3 is moved forward. Instead, the rim 2 can comprise an additional shield component to provide splatter protection. For example, the rim 2 can have a flat top of multiple sizes that can be attached or detached according to the size of the gap created. In another example, an angled top can be affixed to the rim 2.

In embodiments, the visor 3 can extend down past a chin of a user, such that when it is adjusted forward, the visor continues to provide protection from splatter coming from bellow.

Furthermore, to avoid the additional length of the visor 3 coming into contact with a user’s chest or shoulders as users rotate their head side to side, a bottom side of the visor 3 can be tapered. Accordingly, the visor 3 can be tallest in about the center, and gets shorter, in a nonlinear fashion, as you move towards the edges thereof.

In embodiments, corners of the visor 3 can be rounded to avoid sharp edges, that may hit the user’s chest or shoulders.

Referring back to Fig. 1 , the visor 3 can be removably secured to the rim 2 using a ball and hole attachment system. As shown, a plurality of projections 17, such as balls, can be spaced along the outside surface 16 of the rim 2. Further, the visor 3 can have a plurality of openings 22 that are adapted to accept or otherwise receive each of the plurality of projections 17 of the rim 2. As each of the plurality of projections 17 are pushed through each of the plurality of openings 22 on the visor 3, each opening 22 can elastically deform to allow the projections 17 to pass therethrough and then reform to its original shape, removably securing the visor 3 to the rim 2.

As shown, in embodiments, the plurality of projections 17 can be positioned along the outside surface 16 of the rim 2 where a curvature of the rim 2 changes. The placement of the plurality of openings 22 on the visor 3 would then correspond with where a curvature of the visor 3 changes. This ensures that the visor 3 will conform tightly with the rim 2.

In embodiments, the rim 2 can be U-shaped, with a near flat front face 13, sharp corners 14 and opposing lateral sides 15. A plurality of projections 17 can be positioned along an outer surface 16 of the rim, which are used to attach the visor 3. The visor 3 can have a corresponding plurality of openings 22 that are adapted to accept the plurality of projections 17 therethrough by elastic deformation.

Applicant notes that embodiments of the invention can use elastic deformation of the visor to removably secure the visor to the face shield. This can be accomplished because the visor is this and has elastomeric properties. However, face shields used in industries other than the medical industry often cannot rely on the elastic deformation of the visor because of safety reasons, as thicker visors must be used to provide protection of the face from flying projectiles. Embodiments of the medical face shield protects against splash and splatter of liquids and therefore do not require thick visors and so elastic deformation of the visor 3 is feasible.

Embodiments of the invention using elastic deformation for removably securing the visor 3 to the rim 2 is simple and reliable, and allows for easy removal of the visor 3 from the face shield for various purposes, including cleaning.

In an embodiment, each of the plurality of projections 17 can be spherical in shape. In another embodiment, each of the plurality of projections 17 can be half semi-spherical in shape. In such an instance, each of the plurality of projections (being a half semi-spherical) can have a torus channel therebehind allowing the visor to selfcenter. Skilled persons would understand that the corresponding plurality of openings 22 in the visor 3 should have a corresponding shape to the plurality of projections 17, in order to easily secure or remove the visor 3 from the rim 2.

In another embodiment, the visor 3 can have the plurality of projections, while the rim 2 can have the corresponding plurality of openings 22.

As shown, the rim supports the visor along the entirety of a length of the rim and the visor is shaped to fit the shape of the rim. In embodiments, rim 2 provides structural rigidity and stiffness and can better support the visor 3 on the head harness 1 . As shown and in an embodiment, the rim can be U-shaped and accordingly, the visor can also be U-shaped. In embodiments, a different shape of the rim 2 will result in a different shape of the visor 3.

For example, and as shown in Fig. 8, the rim 2 can be a semi-circular shape, and the resulting visor 3 can also be semi-circular in shape. This can be advantageous because there is a reduced cost associated with producing a semicircular visor coated with anti-reflective coating or other coatings. Further, a semicircular visor maintains a consistent distance between the user’s eyes and that of the visor. However, the curvature of a semi-circular visor result in spherical aberrations which can lead to blurring.

In embodiments, the Applicant has found that the shown U-shaped rim and visor reduces optical distortions because there is less curvature in visor that forms part of the user’s field of view. That is, a U-shaped visor has a front face that comprises a curvature that is less than a curvature of a semi-circular visor. With less curvature, there is a reduced possibility of optical distortions and provides the user with a clearer field of view.

Another advantage of a U-shaped visor that a distance between the front face of the visor and the user is consistent, thus providing more clearance for use of loupes and other medical assisting tools. Related to this advantage, an angle of incident light on the visor, originating from a head light worn by a user, is near normal. On certain materials, the intensity of reflected light is minimal at near normal incidence angles. Further, any reflected light would most likely be directed straight back to the head light or forehead, as opposed to reflecting into the eye of the user and causing blind spots for the user.

The near flat front face of the U-shaped visor also reduces the spread of reflected light, thus making it less likely that light from another source will be reflected off the front face and into the user’s eye, which can be perceived by the user as glare. In other words, the near flat front face reduces glare that can be perceived by the user.

To further reduce the effects of reflected light on the user, the visor can be coated with an anti-reflective coating. The anti-reflective coating decreases the amount of light which reflects off the visor and increases the amount of light that passes through the visor. In embodiments, the anti-reflective coating can be applied to the portion of the visor that is in the field of view of the user, to reduce overall costs in production.

The anti-reflective coating is beneficial for a medical face shield with frontal clearance, as the reflection perceived by the user increases as the visor is adjusted further away from the eye. Perceived reflection increases because more of the visor, and the distracting bright spots on it, are in the user’s field of view. Further, as the visor is moved further away from the head, the head is less able to shadow the inner surface of the visor from ambient light. This makes it more likely for ambient light to reflect off the inner surface of the visor and into the eye.

The anti-reflective coating is particularly beneficial when the user has a headlight that is worn behind the shield. This is frequently the case for users who use loupes and require face shields with frontal adjustment. The anti-reflective coating functions to increase transmission of the headlight through the visor, to better illuminate the user's visual workspace, and decrease headlight back reflection, which causes eye strain.

By increasing light transmission, the anti-reflective coating also helps to reduce the visibility of scratches. This allows the visor to be used for longer before being replaced by the user.

The improved light transmission also allows for more ambient light to enter into the shield, allowing the user to see the external world with greater brightness. A low light transmission visor would make the world appear visually dull and cloudy to the user. In an embodiment, the anti-reflective coating has a hydrophobic property.

This is beneficial as the visor needs to be routinely cleaned throughout the day, and the hydrophobic property reduces water droplets which can compromise visibility and can cause water stains when evaporated. Additional benefits can be accrued when the visor is made from anti- reflective plastic which has interference coatings. The thickness of such coatings can be calibrated to equal a particular value, often a quarter or half of a wavelength of visible light, when the light is near normal. This can be beneficial when the shape of the rim is such that reflected light is near normal in the user’s FOV. In an embodiment, the visor can also have a hardness coating for reducing scratches and prolonging a time before the visor needs to be replaced by the user.