WO1998020277A1 - Reflective optics and special stative for video camera mounted on a dental lamp - Google Patents

Abstract

The present invention enables any dental lamp to be converted into an operation lamp with a centrally installed video camera. Furthermore, a video camera with reflective optics and a special stative is mounted on the dental lamp. The special stative allows for the camera to be adjusted so as to have its optical axis parallel to the central beam of the dental lamp. Owing to the reflective optics, the optical axis of the video camera is virtually deflected to the centre of the light beam, so that the video recordings are always made with the best entrance angle from the centre of the dental lamp and, as a result, do not have the slightest shadow. A well trained physician/assistant team should be able in future to apply a treatment using a video monitor with reduced eye strain.

Description

description

U steering optics and special tripod for ide camera mounted on Dental 1 luminaire

The invention is a deflection optics and a special tripod for one

Video camera that can be quickly removed from any dental light.

For documentation and patient demonstration, intraoral cameras are increasingly being used in dentistry in addition to normal video and photo cameras. With these intraoral cameras, the lens is inserted more or less far into the patient's mouth. The illumination of the object - tooth or oral mucosa - is usually done by cold light, light generated by distant halogen lamps, which is guided to the front lens of the lens by means of glass fibers. The intraoral video camera must be operated either by the dentist or his assistant. The treatment must always be interrupted during your application, since either the unobstructed view of the teeth etc. is obstructed or the lens (intraoral) must be removed from the mouth for cleaning due to fogging or dirt (saliva, drilling chips etc.). Since the camera itself is operated with an electrical voltage (usually 12 volts), there is a residual risk of a power accident in the patient's mouth. In summary, these intraoral cameras have the following disadvantages:

1.) additional lighting

Additional lighting is required for their use (see above)

2.) Contamination

The camera optics is contaminated by contact with the patient's mouth and must therefore be disinfected, better, sterilized after each use.

3.) fogging

Due to the temperature differences, cold camera optics / warm mouth of the patient, most intraoral cameras fog up at the beginning of the recording.

4.) Electromagnetic effects

Although all intraoral video cameras are operated with low voltage (12 volts), a residual risk of a power accident cannot be completely ruled out.

5.) poor optical imaging

Since the optical entry openings (lens systems) in these cameras are very small, imaging errors (aberrations etc.) occur more frequently. 6.) poor ergonomics

When using the intraoral cameras, the dentist must interrupt the treatment and take the camera in hand.

The extra-oral cameras in the dental field are usually normal camcorders (camera-recorder combinations), which are attached to a separate tripod (floor or ceiling tripods) or have to be held by the dentist himself with the hand. Either the dental dental light or a separate light source outside the patient's mouth serves as lighting. These "normal" video cameras have the following disadvantages in the dental sector.

1.) Additional lighting

If you want to illuminate the patient's mouth optimally - shadow-free - you need additional lighting that has to come from the direction of the optical axis of the camera (camera light; best for photo cameras: ring flash) 2.) Poor ergonomics and unwieldiness

The practitioner or his assistant need both hands for the admission.

In addition, the patient is given a view of the patient for the duration of the admission

Monitor refuses (since the dentist stands in front of him). 3.) Intraoral recordings with a flanged mouth mirror are only possible to a limited extent.

There are also designs (see, among others, utility model DE 29621838 U1 dated 3.03.97) in which the miniature video camera is combined with the dentist's work area light and thus uses the light from the dental light to illuminate the mouth. These cameras are arranged on the edge of the lamp reflector, i.e. eccentrically, and have the following disadvantage without deflecting optics:

Since the camera image is not centered on the central steel of the dental light at different shooting distances (see parallax error), the camera must not only be refocused when changing the shooting distance, but also reoriented to the operating field, i.e. to the central beam of the dental light . Fully-fledged surgical lights with a centrally integrated camera and straight optics are used in many clinics (including utility model G 88 14. 303.1 from January 12, 1989). They are relatively large and heavy, since several spotlights with their own reflectors are arranged around the camera.

In addition to size and weight, the disadvantages of these surgical lights are a high purchase price. They are not suitable for normal dental practices. Retrofitting the normal dental lamp is not possible.

The disadvantages of the construction types mentioned above can be completely eliminated by the invention:

The invention uses the mobility and illuminance of any dental lamp to achieve optimal video recordings without interrupting the treatment process. On the other hand, the invention makes it possible to achieve an optimally illuminated and shadow-free recording of an object, regardless of the recording distance, since the light source is arranged around the optical axis of the receiving lens and the light beams always run parallel to the optical axis.

Optimal lighting with a dental lamp

In the case of the invention, the optical axis of the objective is moved into the center of the beam path of the dental lamp by the double beam deflection of the periscope optics and the pull-out second mirror (FIG. 1). This avoids parallax errors (FIG. 2) and the image is always taken in the center of the light cone of the dental lamp. An intraoral intake, e.g. the back surface of a tooth can easily be done with a mouth mirror (Fig. 5/1).

By the dentist illuminating the area to be filmed with his mouth mirror (he directs the light from the dental lamp onto the tooth with the mouth mirror), the camera automatically records the illuminated area (Fig. 5/2). Exclusion of contamination and fogging of the optics

The light-mounted video camera with deflection optics makes an intraoral camera unnecessary. This eliminates any contamination of the lens with saliva or blood and therefore disinfection of the lens is necessary. A risk of infection of the patient due to soiled optics is completely excluded.

No electromagnetic effects

Furthermore, the extraoral "intraoral camera" has the advantage that no electromagnetic voltages can occur in the patient's mouth (short circuits, etc.)

Good optical illustration

Due to the relatively large lenses of the deflecting optics (diameter approx. 12-20mm), so much light falls on the CCD (CMOS) chip that a strong bending by the CCD iris or a built-in aperture (06) (Fig. 1) can take place .

The small aperture causes a large depth of field and minimal optical aberrations. Thanks to the telephoto lens with a focal length of 30 to 150mm (depending on the chip surface; normal lens with 1/2 "CCD chip = 7mm), teeth and neighboring teeth are filled in the normal working distance of 600-700mm (lamp - patient's mouth) on the observation If the lamp is brought closer to the patient's mouth, it can be enlarged 25-40 times on a 14 "monitor.

Economy and ergonomics

Thanks to the special lamp stand, any dental lamp can be retrofitted with the invention. The quick-change tripod makes more cameras - e.g. B. in each treatment room another camera - superfluous, since only a tripod is mounted (glued) on each dental lamp and a cable for the video connections / power supply and possibly audio must be laid. For dental treatment, the center of the light cone (= the central beam) of the dental lamp must be aligned with the tooth to be treated. Since the optical axis of the video camera is laid in this center and parallel to the light cone by the deflecting optics, the assistant on the monitor can control the exact setting of the lamp and also the sharpness of the image without the dentist having to worry about it. If the tooth to be treated is shaded by dental instruments or the doctor's fingers, it is also impossible to obtain a perfect image. The dentist and assistant have constant control of the video recording and thus continuous observation and documentation of the dental treatment is possible without interrupting the treatment process. Another advantage is that the double beam deflection (periscope optics) means that all objects are imaged correctly on the observation monitor.

Drawings (Fig 1- 9)

Parallax error:

In photography, the parallax is the angle between the optical axis of the lens, the object to be photographed and the viewfinder. The parallax error - what you see through the viewfinder does not match what is being photographed - is the bigger the closer you get to the object. Transferred to the dental light means that the closer a camera that is mounted on the light comes to the patient's mouth, the further the central beam of the light and the optical axis of the video camera diverge (FIG. 7). In photography, this problem was solved with the SLR technique.

Reference sign

Fig. 1 camera optics on light and

K = camera

C = CCD / CMOS chip of the camera

L1 = dental light

L2 = halogen lamp

L3 = luminaire reflector

SS = beam path of the lamp

SP1 = mirror 1

SP2 = mirror 2, adjustable in length

01 = adapter piece

02 = external telescope

03 = inner telescope

04 = lens system

05 = Bracket for long sliding front mirror

06 = aperture

07 = focusing lever A = optical axis

ZS = central beam of the dental lamp Y = focusing path

Fig. 2 parallax error

L1, L2, L3 = positions of the dental lamp 1, 2, 3 = point of impact of the central beam of the dental lamp at the individual lamp positions

Fig. 3 central beam / optical axis

A = optical axis ZS = central beam of the dental lamp SS = beam path of the dental lamp D = optimal working distance: 700mm Fig. 4 focusing with pins

07 = focusing pins

Y = focusing path

Fig. 5/1 Indirect exposure with a mirror

Fig. 5/2 central ray is reflected on the tooth with a mouth mirror

Fig. 6 camera mounted directly on the outer telescope

K = camera

KK = cable

H = bracket

C = CCD / CMOS chip of the camera

L1 = dental light

SP = mirror, adjustable in length

02 = external telescope

03 = inner telescope 07 = focusing lever A = optical axis

ZS = central beam of the dental lamp

Y = focusing path

Fig. 7 camera tunnel (.. outer housing) with an internally rotatable camera

K = video camera with housing

C = CCD (CMOS) chip

G = outer casing tube

D = lid with integrated mirror

F = camera ring frames with guide bands

S = slot in outer housing

H = lever for rotating the camera

Fig. 8 Upper jaw before / after rotation of the camera in the camera tunnel

G = outer casing tube

C = CCD / CMOS chip

A = jaw position of the lying patient

B = monitor image with patient lying down

C = monitor image after rotation of the camera

Fig. 9/1 lamp reflector with tripod cap and sleeve and Fig. 9/2 lamp tripod

51 = glued-on cap adapted to the reflector

52 = socket

53 = knurled screws

54 = tripod leg, lockable

55 = ball head, lockable in sleeve

56 = sleeve

Claims

Protection claims The deflection optics for the dental video camera system mounted on the dental light is characterized by: Feature 1: The deflection optics have a double 90-degree beam deflection (= periscope). The Beam deflection is achieved using optical mirrors (Sp1 / Sp2) or prisms. These optics can be flanged to any video camera using an adapter (01). The deflection optics enables a parallel shift of the optical axis (A) of the video camera (Fig. 1). Feature 2: A length adjustable (e.g. extendable) second mirror or a prism (Sp2), whereby the optical axis of the video camera can be placed exactly in the center of the beam of any dental light (Fig. 1) The optical axis of the video camera runs parallel and in the middle of the central beam of the dental lamp. Parallax errors are avoided (Fig. 2). Feature 3: A deflection lens with a long focal length (depending on the CCD or CMOS chip: 1/5 ", 1/4", 1/3 ", 1/2" chip) from 30 to 150mm (standard focal length at 1/2 "CCD- Chip = 7mm) The teeth to be treated can be displayed on the observation monitor in a format-filling manner with an adjacent tooth at an average distance (D) between lamp and patient mouth of approximately 600-700mm (Fig. 3). Even larger imaging scales, for example for demonstrating the finest tooth defects or gum disease, are achieved by approaching the dental light and thus the lens up to 300mm from the patient's mouth. A further introduction of the dental lamp would hinder the dentist's view. The imaging scale can be enlarged further by interposing an optical extender (= focal length doubler). Feature 4: A one-handed quick focusing by means of telescoping displacement of the front lens-lens pair (Fig. 4). With the long focal lengths of 30mm to 150mm (with 1/5 "or 1/2" CCD or CMOS chip), the focusing path to focus between the two extreme shooting distances of 300mm and 1500mm is more than 30mm. Fast focusing, which can be achieved with just one hand, is achieved by telescoping the front pair of lenses in the inner tube (or in the outer tube) against the outer tube (or inner tube) of the periscope optics (possibly by means of two pins (07), the fingers are moved against each other). Fast focusing with approximately the same shooting distance can also be achieved by changing the object distance itself (distance between luminaire and tooth) by swiveling the dental luminaire back and forth. Feature 5: With an ordinary dental mirror, which reflects the light of the dental lamp on the tooth surface to be viewed, any tooth surface can be displayed, since the optical axis of the video optics runs exactly in the middle of the light beam of the dental lamp. Intraoral cameras that have to be inserted into the patient's mouth are therefore superfluous (Fig. 5/1). Feature 6: Protection is also claimed for a modification of the deflection optics, whereby the miniature camera is mounted directly on the outer telescope (or inner telescope) and the first mirror (or the prism) is therefore omitted (Fig. 6). Feature 7: Protection claims are also made for a modification of the connection between the camera and the deflection optics. With this connection (FIG. 7), the camera (and thus the image recording chip) can be rotated 90 degrees to the right or to the left against the optics. As a result, rising or falling image lines can be rotated so that they are displayed on the monitor as horizontal lines (Fig. 8). This is particularly useful for advanced training events in orienting viewers who do not follow the operation directly but via a video monitor or projector in an adjacent room. The special tripod for mounting the video camera on the dental light is characterized by: Feature 8: A plate (cap) (S1) made of heat-resistant material with a sleeve (S2) adapted and mounted on the movable, reflector-carrying part (back, top or bottom of the lamp reflector) of the dental lamp (S1) (Fig. 9/1). Feature 9: A quickly lockable miniature tripod with screw or the like in any position (S3) lockable ball joint head (S5 / S6). The (ball) joint enables the optical axis of the camera to be aligned parallel to the central beam of any dental lamp (Fig. 9/2). A one-time adjustment is required so that the camera can be aligned parallel to the light's beam path. The miniature tripod also enables the video camera to be quickly removed and reattached, e.g. to be brought to another treatment room.