Technical Field of the Present Invention

The present invention relates to a lens and lighting device for use in dental imaging applications. More particularly, the present invention relates to a lens and lighting device that is attachable and removable from a communication device (such as a smartphone) to be used in dental imaging applications.

Background of the Present Invention In the past decades, use of digital photography has become standard for dental practices. The applications for clinical photography in dentistry include: diagnosis and treatment planning, laboratory communication, legal and forensic documentation, as well as patient education and communication (Terry et al., 2008, Compend Contin Educ Dent. 92, pp. 432-6, 438, 440-2, 450, 462). The quality of the dental image is very important, especially with such a wide range of applications. Dental photography comprises extraoral, perioral and intraoral photography and each region has unique considerations that must be kept in mind to acquire the best possible images. The main difficulties that need to be addressed for intraoral photography are the inaccessibility of oral structures, lighting inside the mouth, framing of the image and reproducibility. For example, as the objects to be photographed, such as teeth and mucous membranes of the mouth, are hidden inside the oral cavity, special lighting equipment is needed. Also, as these objects are very small, problems of macrophotography such as magnification ratio, depth of field and perspective distortion need to be taken into account. In addition, due to the high contrast and presence of reflective surfaces inside the oral cavity, exposure concerns emerge. Dental photography needs to balance these concerns in order to successfully provide comprehensive images that reflect the outline, surface texture and color of the object and even some inner structures of the semitransparent teeth (Bengel, 2006, Mastering Digital Dental Photography, 2nd ed., Quintessence, Chicago, IL).

For high quality dental photography, the camera body itself is not as critical as the lens and lighting selections. Macro lenses (close-up lenses) are the ideal choice in terms of large magnification ratios (e.g. 1 : 1) and focusing at close range. Another parameter is the aperture, which determines the amount of light entering the lens. To obtain the maximum depth of field that is required for dental imaging, the aperture opening must be small, so lenses with large f-stop values (e.g. f-22) are preferable. Point flash, ring flash or twin flash can be used as a light source. While use of ring flash is acceptable, twin flash provides the best images. Twin flash consists of two flashes placed on either side of the lens, with no light coming from the top or bottom. Because the light comes in at a slight angle, there is less specular reflection and some slight shadowing is created which gives depth to the image. The line angle, color effects, subtle color gradations, translucency levels and crack lines can be seen by use of a twin flash (Terry et al., 2001, J Calif Dent Assoc. 29, pp. 735-742).

Currently, DLSR (digital single-lens reflex) cameras are the most commonly used cameras for dental imaging applications. However, it has increasingly become possible to use compact digital cameras and smartphones. The advantage of using smartphones is that they are relatively inexpensive, more widely available and less cumbersome to carry. In addition, smartphones allow convenient capture and transmission of dental images, as they produce smaller sized files, which is an advantage in teledentistry applications (Parrish et al., 2014, J Health Inform Dev Ctries. 8, pp. 33-41).

One example of use of smartphones in dentistry applications in the prior art is TW 2015/21686 A. This application discloses a device attachable to the camera of a smartphone that can objectively identify teeth color. A truncated square pyramidal spacer is mounted on a smartphone case so that the smaller opening is placed on top of the lens and flash of the smartphone. The inside of the spacer is coated with black neoprene foam to prevent the light from coming through. Two linear polarization filters are placed at the larger opening of the spacer, orthogonal to each other corresponding to the lens and the flash respectively to obtain zero reflection of light from reflective surfaces of teeth. The device makes it possible to determine the color of teeth objectively regardless of ambient conditions and compare it with a database to find a match via an application from the smartphone.

The main disadvantage of smartphones is that they don't offer lens and lighting selections suitable for dental imaging as described above. Their lenses don't provide the needed magnification and depth of field and the available flash is generally a point flash. However, these shortcomings can be overcome by a lens and lighting device that is attachable to and removable from the camera of a smartphone that is specifically designed with the consideration of dental imaging in mind. Examples of lenses that are attachable to smartphones and other communication devices can be found in the prior art. One such example is US 9,188,764 B2, which discloses a lens component that removably attachable to a communication device. The lens component comprises a retainer portion and a lens portion. The retainer portion is removably attachable to a communication device and ensures that the lens portion is correctly aligned and can operate with the camera of the communication device. The lens portion may be a fisheye lens, a wide-angle lens, a macro lens or any other type of lens. The lens portion is removably attachable to the retainer portion so that different types of lenses may be used interchangeably. This lens component is commercially available under the name olloclip®. However, this invention only makes use of the point flash that is available on the communication device, which is not ideal for dental imaging applications. The present invention aims to improve on the problems described in the prior art. The invention proposes a lens and lighting device that is removably attachable to a communication device such as a smartphone for use in dental imaging applications. The invention comprises a close-up lens and a small aperture which is attached to the camera of a communication device to obtain the magnification and depth of field needed for dental imaging. The invention also comprises a twin flash system to optimally highlight the contours and color variations of a patient's teeth. In this manner, the invention aims to provide an inexpensive, practical and accessible alternative for use in dental photography applications.

The present invention provides a lens and lighting device for use in dental imaging applications as provided by the characterizing features defined in Claim 1. Objects of the Present Invention

The object of the invention is to provide a lens and lighting device that is removably attachable to a communication device such as a smartphone for use in dental imaging applications.

It is a further object of the invention that the lens and lighting device comprise a lens system and flash system, whereby the lens system is aligned with the camera of the communication device so that the lens can provide greater magnification and depth of field and the flash system is aligned with the flash of the communication device so that light emitted from said flash is transferred to a twin flash system via optical fibers. It is a further object of the invention that polarized filters are placed in front of the lens of the lens system and the flash of the flash system in such a manner that their polarizing directions are orthogonal to each other so that cross-polarized lighting is obtained. Brief Description of the Technical Drawings

Accompanying drawings are given solely for the purpose of exemplifying a lens and lighting device, whose advantages over prior art were outlined above and will be explained in brief hereinafter.

The drawings are not meant to delimit the scope of protection as identified in the Claims, nor should they be referred to alone in an effort to interpret the scope identified in said Claims without recourse to the technical disclosure in the description of the present invention. The drawings are only exemplary in the sense that they do not necessarily reflect the actual dimensions and relative proportions of the respective components of the system. Figure 1 demonstrates a top view of an embodiment of the present invention.

Figure 2 demonstrates a side view of an embodiment of the present invention as depicted in Figure 1. Figure 3 demonstrates a top view of a lens system of the present invention as depicted in Figure 1.

Figure 4 demonstrates a sectional view of a lens system of the present invention as depicted in Figure 1.

Figure 5A demonstrates a top view of a diaphragm of the present invention as depicted in Figure 1.

Figure 5B demonstrates a side view of a lens of the present invention as depicted in Figure 1.

Figure 6A demonstrates a sectional view of a flash cable of the present invention as depicted in Figure 1. Figure 6B demonstrates a sectional view of a flash of the present invention as depicted in Figure 1.

Figure 7 demonstrates a side sectional view of a flash of the present invention as depicted in Figure 1.

Figure 8A demonstrates a sectional view of a lens system with polarized filter. Figure 8B demonstrates a side view of a flash system with polarized filter.

Figure 9 demonstrates a top view of an embodiment of the present invention attached to a clip. Figure 10 demonstrates a side view of an embodiment of the present invention attached to a clip as depicted in Figure 9.

Detailed Description of the Present Invention The following numerals are referred to in the detailed description of the present invention:

10 Lens and lighting device

20 Lens system

30 Flash system

201 Base

202 Lens groove

203 Cable groove

204 Lens

205 Diaphragm

206 Aperture

207 Camera attaching means

208 Flash attaching means 209 Flash cable attaching means

210 Polarizing filter attaching tab

301 Flash

302 Optical fiber

303 Flash cable

304 Fixed cable

305 Adjustable cable

306 Softbox

401 Lens polarizing filter

402 Flash polarizing filter

403 Polarizing filter attaching means

404 Polarizing filter attaching slot

500 Lens and lighting clip

501 Clip

502 Clamp

503 Screen protector

504 Flash cable protector

Figures 1 and 2 illustrate an embodiment of the present invention, referred to as lens and lighting device (10). Lens and lighting device (10) comprises lens system (20) and flash system (30). Flash system (30) comprises flash (301) and flash cable (303). Lens system (20) is attachable to the camera of a communication device such as a smartphone via base (201). Lens system houses lens (204) and flash cable (303) so that they are respectively aligned with the camera and flash of a communication device such as a smartphone. The light emitted from the flash of a smartphone is transferred to flashes (301) of lens and lighting device (10) via optical fibers (302) encased in flash cable (303). Flash cable (303) comprises a stationary fixed cable (304) and two adjustable cables (305). Fixed cable (304) is divided into two adjustable cables (305) which form a twin flash system that is ideal for dental imaging. Twin flash system allows the contours and line angles of teeth to become more pronounced. It is also important that flashes (301) are placed below the camera to optimally capture the line angles. Adjustable cables (305) are made of a pliable material a plastics based flexibly deformable material so that flashes (301) can easily be positioned in and/or around a patient's oral cavity as desired.

Figures 3, 4, 5A and 5B illustrate lens system (20) in greater detail. Lens system (20) comprises base (201), lens groove (202), cable groove (203), lens (204), diaphragm (205), aperture (206), camera attaching means (207), flash attaching means (208), flash cable attaching means (209) and polarizing filter attaching tab (210). Base (201) is placed on the camera and flash of a communication device such as a smartphone so that lens groove (202) is aligned with the camera and cable groove (203) is aligned with the flash and secured in position by camera attaching means (207) and flash attaching means (208) respectively. Camera attaching means (207) and flash attaching means (208) have an inclination of about 4° with respect to the vertical axis. Some models of lens and lighting device (10) may also comprise protrusions (P) placed in a suitable location to facilitate attachment of lens and lighting device (10) to a communication device. For example for an iPhone, a protrusion aligned with the microphone between the camera and the flash may be present.

Lens groove (202) also contains lens (204) and diaphragm (205). Lens (204) is a close-up lens, preferably with a shape factor between +1 and +2. A close-up lens is needed to achieve large magnification ratios (e.g. 1:1) and focusing at close range which are important for successful dental photography. Diaphragm (205) having an aperture (206) is placed below lens (204). Preferably aperture (206) has a diameter between 1 mm and 1.3 mm. As mentioned above, a small aperture is needed to obtain greater depth of field. Flash cable (303) is attached to cable groove (203) by flash cable attaching means (209). Figures 6A and 6B illustrate flash system (30) in greater detail. Figure 6A shows the end of fixed cable (304) that faces the flash of the smartphone. In one embodiment of the invention, fixed cable (304) contains 12 optical fibers (302). Preferably optical fibers (302) are 1 mm in diameter. Optical fibers (302) are divided evenly to adjustable cables (305) so that each adjustable cable (305) contains 6 optical fibers (302) respectively. Optical fibers (302) transfer light emitted from the flash of the smartphone to flash (301) of lens and lighting device (10). In one embodiment of the invention, at least one optical fiber contained in a flash (301) can be unhoused and pulled forward so that the oral cavity of a patient can be better illuminated and more detailed information can be gained on color variations and chipped or broken teeth.

Figure 7 illustrates an alternative embodiment of flash (301), where flash (301) is covered by softbox (306). Softbox (306) consists of a hard plastic edge with white fabric such as ripstop nylon stretched across flash (301). Softbox (306) diffuses the light evenly and prevents harsh lighting with a lot of contrast and marked divisions between light and shadow, which is advantageous when taking dental photographs. Figures 8A and 8B illustrate an embodiment of the invention where polarizing filters are attached to lens system (20) and flash system (30). Polarizing filters (401 and 402) are attached to lens system (20) and flash system (30) respectively by polarizing filter attaching means (403). Polarizing filter attaching means (403) is shaped such that polarizing filters (401 and 402) can be conveniently snapped into their respective places on lens system (20) flash system (30). Lens system (20) additionally comprises polarizing filter attaching tab (210) to secure lens polarizing filter (401) into place and corresponding polarizing filter attaching slot (404) on polarizing filter attaching means (403) ensures that lens polarizing filter (401) keeps its position. Polarization directions of lens polarizing filter (401) and flash polarizing filters (402) are orthogonal to each other. Preferably lens polarizing filter (401) is at 90° and flash polarizing filters (402) are at 180°. This arrangement produces cross-polarized lighting. Cross-polarized lighting enhances contrast and eliminates specular reflections which allow the contours and color variations of teeth to become more pronounced, resulting in a higher quality dental image. Figures 9 and 10 illustrate another embodiment of the present invention, referred to as lens and lighting clip (500). Lens and lighting clip (500) comprises lens and lighting device (10) which is attached to a clip (501) to secure said lens and lighting clip (500) around a smartphone so that lens (204) and flash cable (303) are aligned respectively with the camera and flash of said smartphone. Clip (501) can be fastened around the smartphone by clamp (502). Inside wall of clip (501) corresponding to the screen of the smartphone is covered by screen protector (504) to prevent activation of the touchscreen and to generally protect the screen of the smartphone. Screen protector (504) is preferably made of fabric such as velvet. When not in use, the end of the flash cable (303) that is operationally housed in cable groove (203) can be housed in flash cable protector (504). Clip (501) and clamp (502) may be made out of metal such as aluminum or plastic such as polycarbonate.

In a variation of the invention, said lens system (20) is rotatably mountable around said flash cable (303) so that the lens and lighting device (10) of the invention can be universally used in different smartphone model by respective manufacturers. More specifically, when the lens system (20) is fixedly attached to the camera of a smartphone in a removable manner, its rotatable position allows the user to mount the clip (501) and fixate the position of the lens system (20). Therefore, the lens and lighting device (10) is suitable for use with communication devices where the flash is placed above or below the camera relative to the smartphone surface.

In a variation of the invention, said flash cable (303) is preferably enclosed by an additional tubular shielding element (not shown) so that it is stationarily retained in a fixed position and only said adjustable cables (305) at the end portions of said flash cable (303) can be given a changeable position. It is to be noted that other arrangements are possible with different materials to provide a stationary tubular body leading to flexibly displaceable end portions. In accordance with the invention, a dedicated camera application may manage different viewing modes such as anterior, posterior or extra oral viewing and shooting modes. In one embodiment of the invention, a lens and lighting device (10) is proposed, comprising lens system (20) and flash system (30) constructed to be removably attachable to a communication device from a camera and flash of said communication device.

In a further embodiment of the invention, said flash system (30) comprises flashes (301) and flash cable (303).

In a further embodiment of the invention, said lens system (20) comprises camera attaching means (207) and flash attaching means (208) on base (201) configured to be removably attachable to camera and flash of said communication device respectively.

In a further embodiment of the invention, said lens system (20) houses lens (204) and flash cable (303) in lens groove (202) and cable groove (203) respectively.

In a further embodiment of the invention, said lens (204) and flash cable (303) are in optical communication with the camera and flash of said communication device respectively.

In a further embodiment of the invention, the transfer of light emitted from the flash of a communication device to flashes (301) is effectuated by optical fibers (302) encased in flash cable (303).

In a further embodiment of the invention, said flash cable (303) comprises a stationary fixed cable (304) and two adjustable cables (305). In a further embodiment of the invention, said fixed cable (304) is divided into two position adjustable cables (305) which are attached to flashes (301) in a twin flash system. In a further embodiment of the invention, said flashes (301) are placed below the camera.

In a further embodiment of the invention, said lens system (20) comprises base (201), lens groove (202), cable groove (203), lens (204), diaphragm (205), aperture (206), camera attaching means (207), flash attaching means (208), flash cable attaching means (209) and polarizing filter attaching tab (210).

In a further embodiment of the invention, said base (201) is attachable to the camera and flash of said communication device such that lens groove (202) is aligned with the camera and cable groove (203) is aligned with the flash.

In a further embodiment of the invention, said lens groove (202) houses lens (204) and diaphragm (205).

In a further embodiment of the invention, said lens (204) is a close-up lens.

In a further embodiment of the invention, said lens (204) has a shape factor between +1 and +2.

In a further embodiment of the invention, said diaphragm (205) having an aperture (206) is placed below lens (204). In a further embodiment of the invention, said aperture (206) has a diameter between 1 mm and 1.3 mm.

In a further embodiment of the invention, said fixed cable (304) contains 12 optical fibers (302).

In a further embodiment of the invention, said optical fibers (302) are 1 mm in diameter. In a further embodiment of the invention, said optical fibers (302) are divided evenly to adjustable cables (305) in the manner that each adjustable cable (305) and flash (301) contains 6 optical fibers (302).

In a further embodiment of the invention, at least one optical fiber contained in a flash (301) can be unhoused and pulled out of said flash (301).

In a further embodiment of the invention, said flash (301) is covered by softbox (306). In a further embodiment of the invention, polarizing filters (401 and 402) are attached to lens system (20) and flash system (30).

In a further embodiment of the invention, said polarizing filters (401 and 402) are fastenable to lens system (20) flash system (30) via polarizing filter attaching means (403).

In a further embodiment of the invention, said polarizing filter attaching means (403) comprises a polarizing filter attaching slot (404) in alignment with said polarizing filter attaching tab (210) such that said lens polarizing filter (402) is non-rotatable around lens system (20).

In a further embodiment of the invention, polarization directions of lens polarizing filter (401) and flash polarizing filters (402) are orthogonal to each other.

In a further embodiment of the invention, said lens polarizing filter (401) is at 90° and said flash polarizing filters (402) are at 180°.

In a further embodiment of the invention, said lens and lighting device (10) is attached to clip (501) In a further embodiment of the invention, said clip (501) is fastenable around said communication device by clamp (502) in such a manner that lens and lighting device (10) is aligned with the camera and flash of said communication device. In a further embodiment of the invention, inside wall of said clip (501) corresponding to the screen of a communication device is covered by screen protector (504).

In a further embodiment of the invention, said clip (502) comprises a flash cable protector (504) whereby flash cable (303) is housed during inactivity.

In a further embodiment of the invention, said communication device is a smartphone.