The present invention relates to an imaging means particularly for recording images from the teeth and the mouth region, said imaging means comprising an image-recording device such as a video camera, an object illumination system, optical elements, an instrument connection cable and a connector.
The invention also concerns a dental unit including at least one instrument connector, whereby the control system of the dental unit steers the physical variables related to the use of an instrument attached to said instrument connector. The invention further concerns a method of connecting an imaging means to a dental unit.
An intraoral camera is an imaging means based on video image recording, most generally used by a dentist as an accessory for imaging the teeth and the mouth region and making a diagnosis on these anatomic regions. An intraoral camera facilitates accurate imaging of a single tooth, a part thereof or any other region of the mouth, complemented with a full-face picture. Pictures taken with an intraoral camera can be recorded in a storage means and, with the help of the stored pictures, the outcome of the care can be elucidated by comparing pictures taken before and after the care. In conjunction with an ongoing care, the intraoral camera can be utilized for showing the patient a specific part of the mouth needing care, thus motivating the necessity of the care for the patient.
In conventional intraoral camera systems, the imaging means comprises a base unit and a hand-held imaging instrument, later in the text called a camera handpiece. The base unit typically includes a power supply, a control electronics unit and a light source. Further there is required a video monitor for displaying the image and possibly storage means for archiving the pictures. Light generated by the light source is generally taken from the base unit to the camera handpiece along a light guide. Typically, the video camera circuitry is located in the base unit and the light-sensitive image sensor element in the handpiece. During an imaging session, the tip of the camera handpiece with its light output exit is taken close to the object to be imaged and the image is projected via the imaging optics onto the light-sensitive image sensor and further in an electrical format to the video camera electronics, and therefrom as a video signal to a display or storage means.
To avoid deterioration of image quality due to shadows, the illumination of the object to be viewed by an intraoral camera must be made as uniform as possible. Generally, light is launched onto the viewed object from the tip of the camera handpiece via an annular light output exit adapted to surround the imaging optics. The better the object illumination the smaller lens aperture of the video camera optics can be used, whereby the depth of field of view can be extended. Particularly for dental imaging, a large depth of field is an essential factor contributing to both the ease of operation and quality of imaging inasmuch the need for constant refocusing is eliminated.
Generally, an intraoral camera system comprises a separate, bulky base unit which causes problems to the positioning of the unit in the frequently operating premises of a dentist. In conventional imaging means, the object illumination systems are very complicated inasmuch the light is transferred from the base unit along an optical light guide to the tip of the camera handpiece, whereby a considerable faction of the light source output is lost on the light mission path. Frequently, the output intensity of light exiting from the tip of the handpiece is insufficient to achieve a satisfactory depth of field. Moreover, the optical fiber extended from the base unit to the handpiece is subject to damage and makes the connection cable thick and stiff, whereby the handpiece located at the end of the connection cable becomes difficult to handle.
The problems associated with a separate base unit can be overcome by connecting the intraoral camera directly to the dental unit, whereby the existing functions of the dental unit can be utilized for the control of the imaging means. E.g., patent publications EP 678 280 and DE 40 09 439 disclose embodiments in which the equipment manufacturer has already reserved one or a given number of instrument places on the dental unit console for connecting the imaging means. While in some constructions the user has an option of mounting the imaging means onto a desired instrument place through dismantling and reassembling the instrument console, obviously this arrangement is not compatible with the normal operating routine of a dentist. Conventionally, the dedicated instrument connectors do not support any other instruments than the imaging means and, conversely, the imaging means cannot be connected to any other instrument connector. These dental units lack the means for identifying the type of attached instruments and controlling the dental unit on the basis of such identification signals. However, for the convenience of tie dental unit user it would be optimal to have all the required dental instruments to be quickly and effortlessly connectable to any desired instrument connector and, moreover, in any desired orderxe2x80x94meaning that the dental unit should be equipped with general-purpose instrument connectors to which a camera or other dental accessory can be attached as desired. Particularly in dental clinics in which a greater number of dentists than one use the same dental unit alternately and each dentist desires to organize the order of their own instruments according to a preferred operating convenience, said novel type of dental unit facility is considered most welcome.
From patent publications EP 479 868, EP 110 200 and JP 192 3861, it is known to provide dental units with codable quick-connect connectors in which onto the connector pins can be switched the different physical parameters required to steer the instruments according to the operating situation. However, these prior-art dental units have not been equipped with facilities for connecting also an imaging means to such an instrument connector and for transferring the image signal via the instrument connector.
It is an object of the present invention to eliminate the above-mentioned drawbacks by virtue of providing a novel technique of connecting dental instruments to a dental unit.
It is a further object of the present invention to provide a novel connection technique of dental instruments by virtue of which method a dental unit can identify an imaging means or other dental instrument attached to a given instrument connector thereof and then switching the parameters and signals required for the control of said dental instrument to pass via said instrument connector of the dental unit.
It is still a further object of the present invention to provide a new type of imaging means such as an intraoral camera with advantageous properties suited for use in the above-described environment, whereby said imaging means does not require a separate base unit, but instead can be connected directly to a dental unit thus utilizing the existing functions of the dental unit.
It is a particular object of the invention to provide such an imaging means connection on a dental unit that, by virtue of said connection, to one and the same instrument connector can be attached either an imaging means or any other type of dental instrument, whereby all the instrument connectors of the dental unit can be equipped with said type of connection suitable for connecting different kinds of instruments thereto.
To achieve the above-described goals and others to be mentioned later in the text, the imaging means, dental unit and method according to the invention for connecting an imaging means to a dental unit are characterized by what is stated in the appended claims.
The benefits of the invention include that, in the combination of an imaging means with a dental unit according to the invention, the imaging camera can utilize the resources of the dental unit such as electricity, water, compressed air, control electronics and the instrument connectors themselves that are already provided for the needs of other dental instruments. According to the invention, the dental unit identifies the instrument attached to the instrument connector and switches thereon the physical variables required for any particular instrument function. As a further benefit of the invention may be mentioned that, via the instrument connector according to the invention, the dental unit can receive information variables such as a video signal and perform further transfer thereof to, e.g., a display device.
For the identification of instruments, the specific identification signal can be generated with the help of any conventional coding technique based on such elements as resistors, switches, etc. adaptable to function in conjunction with the instrument connector. Thus, the invention makes it possible to configure the imaging means with its connections, power feed and cooling medium circulation in a manner which is substantially more advantageous than prior-art combinations based on separate devices and control Systems. A still further benefit is that the dental unit may initially be equipped with a facility for connecting an imaging means, whereby the means such as a video camera itself be acquired later. Hence, a single camera can be swapped between a plurality of compatible dental units, whereby a dentist may operate in a number of separate dental units a single set of instruments, typically owned by the dentist him/herself. The dental unit can be furnished with such instrument connectors that any type of instrument can be attached to any instrument connector provided with, e.g., a conventional multiplex interface. Alternatively, one or some instrument connectors may be exclusively assigned to serve a given instrument or a plurality thereof.
The imaging means arrangement according to the invention is essentially characterized in that the object illumination system of the camera is adapted into the hand-piece portion of such an instrument. In the present arrangement, the light need not be conveyed over a long path, whereby light transmission losses are reduced and the thick light guide can be omitted from the instrument cable.
An intraoral camera implemented according to the invention does not require a separate base unit, but instead, the camera can be integrated with a conventional dentist""s dental unit. Thus, the intraoral camera may be designed into a miniature device that is readily available in parallel with other dental instruments. The electrical supply and cooling medium of the intraoral camera can be furnished from the dental unit.