JP2006528045A - Fluorescent filter for histological examination and image processing - Google Patents

Abstract

A tissue examination system is disclosed as various embodiments.
The tissue examination system includes a handle, a light source element (eg, an LED), a filter, and in some embodiments a mirror. In a preferred embodiment, the light source element and filter are mounted on the end of the handle, which allows direct observation of the fluorescence due to body tissue in various forms. In others, the mirror is integrated with the filter and light source assembly to reflect and filter the fluorescence to the viewer. On the other hand, the shield prevents ambient light from entering the field of view as extra light and interfering with the tissue examination.
[Selection] Figure 14

Description

Display of related applications

  This application includes subject matter related to US patent application Ser. No. 10 / 209,574 (inspection application) filed Jul. 31, 2002, which is hereby incorporated by reference in its entirety. The

Field of Invention

  The present invention relates generally to devices and methods for examining body (especially teeth and skin) tissue, and more particularly to devices and methods involving the detection of different fluorescence emissions from abnormal and healthy tissue.

background

  For example, devices and methods have been proposed that use fluorescence to detect other abnormal states of body tissue such as caries, plaque, tartar and cancer. In such a device, the amount of light in a given wavelength region that irradiates the tissue needs to be controlled, and the amount of fluorescence induced thereby depends on the tissue properties in a controlled manner. Furthermore, in order to provide an optimal contrast between the emitted light and the emitted fluorescence, the amount of light in the illumination wavelength region must be blocked from reaching the detector and / or observer. Nevertheless, most proposed and existing devices only take into account these aspects.

  For example, US Pat. No. 3,711,700 relates to exposure light for inspecting tooth surfaces. The exposure light is designed to be used with a fluorescent dye such as sodium fluorescein. The exposure light includes a light source and a dichroic reflector that is provided on the back surface of the light source and reflects blue light forward and reflects the remaining light backward. The second dichroic filter is located in front of the light source, passes blue light, and reflects infrared light backward. The mirror reflects yellow light to the viewer and allows other wavelengths to pass. This device does not provide a means to control the amount of ambient light that enters the oral cavity and therefore causes mutual interference with fluorescence.

  U.S. Pat. No. 4,266,535 discloses a diagnostic lamp used with a fluorescent dye to inspect the tooth surface. The lamp includes an incandescent light source used with a lens to provide a divergent beam of light. The blue filter is used with the dichroic filter used to filter this light, which hits the fluorescent dye. The fluorescence generated thereby is observed with a mirror that is bent and adjusted. This device also does not control the amount of ambient light that enters the oral cavity, and the induced fluorescence is not observed alone, and the induced fluorescence is observed as a whole with the reflected excitation light. Is done.

  U.S. Pat. No. 5,957,687 discloses another diagnostic unit that includes a filtered light source and a mirror housed in a housing. The filtered light is concentrated in the blue frequency region, causing the fluorescent dye to fluoresce. This can be observed with a mirror.

  U.S. Pat. No. 4,290,433 discloses a method and apparatus for detecting caries in human teeth using luminescence. The luminescence from this tooth is measured at two predetermined wavelengths, one of which produces almost the same luminescence on the surface containing the caries and the surface not containing the caries and the other on the surface containing the caries the higher light emission. A signal is generated according to the difference in intensity at the two measured wavelengths. Basic measurements are made in areas that have not deteriorated, after which the probe targets other areas and evaluates the presence or absence of caries.

  U.S. Pat. No. 4,515,746 describes an apparatus for visually observing a mismatch in the luminous capacity of the tooth surface. The disclosed device includes an argon laser for generating visible light in a predetermined wavelength region, which produces light emission from the tooth surface. The absorption filter is used to reduce reflection and emission of laser light within a predetermined wavelength region. In this form, non-responsive tooth surfaces such as caries can be observed as dark areas.

  U.S. Pat. No. 5,894.620 discloses an electric toothbrush with means for determining the position of tooth floss. The electric toothbrush includes an optical fiber for carrying excitation radiation to the tooth surface and an optical fiber for receiving a reflected luminescent or fluorescent signal. The reflected signal is processed to trigger a light or audible signal indicating the presence of plaque.

  Shields are used in combination with illuminators, and the most common shields known are detectors (eg, photographic cameras) or sunshades and sunglasses to prevent human eyes from being exposed to strong sunlight It is. In the dental field, shields are commonly used in therapeutic light systems such as the shields disclosed in US Pat. Nos. 5,288,231, 6,155,823, and 4,615,679. Yes. Each of these patents describes a light shield used in the therapeutic light system, where the shield substantially attenuates the light (blue region), thereby causing the operator to be harmful and Protects against disturbing direct and indirect light radiation. Apart from the difference in shape, all therapeutic light shields are common in that they protect the user's eyes from harmful light emissions generated by the therapeutic light gun. These shields do not control the amount of ambient or treatment light that reaches the healing material of the tooth tissue and are not intended to substantially pass the fluorescence induced in the tooth tissue for observation purposes .

  In view of such a background, it can be combined with various detection techniques, and only the amount of excitation light in a specific wavelength region for irradiating the tissue to be examined can be controlled and transmitted from the tissue being examined. There is a need for a shield that can reduce the exposure of such tissue to ambient light while sending the resulting fluorescence to a detector that is substantially integrated into the observer or illumination device. The present invention is directed to such demand.

Overview

  Accordingly, in one embodiment, the present invention provides a shield for use with a hand held instrument used to detect abnormal tissue conditions. The instrument includes a light source that generates light in a predetermined wavelength region that produces different fluorescent emissions that are visually detectable from normal and abnormal body tissue. The shield exposes the tissue to be examined with light from the light source and attenuates the surrounding light. Fluorescence emitted from the tissue is conveyed through the shield wall and the excitation wavelength light is blocked, thereby improving the direct visualization of the different fluorescence of normal and abnormal body tissue.

  In another embodiment, the present invention provides a shield for use with an intraoral fluorescent camera with an integrated illumination device. In this embodiment, the shield blocks ambient light and the light from the irradiator is directed toward the tissue being examined. The fluorescence emitted from the tissue is guided toward the camera sensor. For quantification, the shield in this embodiment is a distance holder for securing on the one hand a fixed distance between the light source and the tissue and on the other hand a fixed distance between the tissue and the camera. This makes it possible to control the amount of radiant power that irradiates the tissue and the corresponding amount of emitted fluorescence depending on the properties of the tissue.

  In some forms of this embodiment, the shield is formed of a deformable material. In others, a cylindrical shape, a cone shape, or a partial spherical shape is adopted. In some embodiments, the mirror is disposed on or within one or more inner surfaces, thereby providing other viewing angles. In other embodiments, at least a portion of the shield has a magnifying characteristic, which allows an observer to magnify the observed oral structure, and in other embodiments, the mirror has a magnifying characteristic. is doing.

  The present invention provides improved and selectable instruments, devices and methods for examining tissue abnormalities, such as examining dental surfaces for bacterial metabolites that are potentially indicative of the presence of caries or plaque. Additional embodiments will be apparent to those skilled in the art from the description herein, as well as the structure and advantages of the present invention.

Detailed description

  In order to facilitate an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. However, it is not intended to limit the scope of the invention, and modifications and further modifications of the described embodiments and other applications of the inventive principles described herein are contemplated by the present invention. Should generally be understood to occur to those skilled in the relevant arts.

  The present invention generally relates to a body tissue examination instrument, and in particular, a filter that can efficiently shield direct light emitted from an LED from being directly seen and provide a clearer image of the tissue. The present invention relates to an instrument and method for tissue examination using a structure. Since some of the components of the present invention are similar to those described in the above-mentioned inspection application, a detailed description of certain common elements is omitted in the present invention and these are incorporated herein by reference. It becomes.

As used herein, “filter” means that only a selected wavelength of light can pass through the object or layer.
1 and 2 show a dental instrument according to a first embodiment of the present invention. In FIG. 1, a dental instrument 10 includes a handle portion 11 and a tip portion 12 connected to the handle portion 11 at a predetermined angle. A light emitting diode (LED) 13 is attached to the tip 12, and a filter structure 14 is attached to the tip 12 so as to surround the LED 13 in the vicinity of the LED 13. The LED 13 emits light having a peak intensity preferably between about 380 and 500 nm, more preferably between 390 and 450 nm.

  When this instrument is used, as shown in FIG. 2, at least a portion of the tip 12 is inserted into the mouth such that the open end of the filter structure 14 is in direct contact with the tooth surface. The instrument 10 emits light from the LED 13 to the tooth surface, and the autofluorescence generated on the tooth surface is observed through the filter structure 14. Since the open end of the filter structure 14 is in direct contact with the tooth surface and the light from the LED 13 does not leak outside the filter structure 14, direct visualization of the light from the LED 13 is efficient. To be prevented.

  A second embodiment is shown in FIGS. The dental instrument 20 has a conical shape and includes a filter structure 22 that is connected to the tip 12 in the vicinity of the LED 13. The filter structure 22 has a narrow open end that is secured to the tip 12 and a wide open end that is directed to the tooth surface. The dental instrument 20 can be used in the same way as the dental instrument 10 (see FIG. 1), and a wider tooth surface is covered by the filter compared to the teeth covered in the first embodiment (see FIG. 2). (See FIG. 4).

  5 and 6 show a third embodiment. In FIG. 5, a dental instrument 30 includes a filter structure 32 having a generally spherical shape. The filter structure 32 is provided in the same manner as in the second embodiment, and can cover teeth as in the second embodiment. In addition, the filter structure 32 has a magnified action and can provide a magnified view of the tooth surface in addition to the filtering action.

  FIG. 7 shows a fourth embodiment in which a dental instrument 40 has a filter structure 42 that is partially conical and partially hemispherical. A mirror 43 that partially covers the inner surface of the filter structure 42 is provided on the inner surface of the filter structure 42. In some forms of the fourth embodiment, a portion of the filter structure 42 that does not have the mirror 43 has a magnifying characteristic. In other forms, the mirror 43 may be anti-fog treated (one skilled in the art). To reduce condensation and accumulation of liquid on the mirror surface. According to the fourth embodiment, the dental instrument 40 irradiates the tooth surface with light from the LED 13, and the fluorescence is reflected by the mirror 43 and observed through the filter structure 42.

  8 and 9 show a fifth embodiment. As shown in FIG. 8, the dental instrument 50 includes a handle portion 11 and an LED / filter structure assembly 52 that is provided at an end of the handle portion 11 at a predetermined angle. The LED / filter structure assembly 53 includes a ring 53, one or more LEDs 13, and a filter 55. The LED 13 is provided on one side of the ring 53 so as to irradiate the tooth surface, and the filter is provided on the inner side of the ring 53. In use of the dental instrument 50, the ring 53 is held in the vicinity of the open mouth or inserted into the mouth and located in the vicinity of the tooth surface as shown in FIG. 9, whereby the LED 13 faces the tooth surface. . The light emitted from the LED 13 hits the teeth, and the fluorescence generated by the teeth is observed through the filter 55. In the dental instrument 50, the filter 55 may be formed with an expanding characteristic so that an enlarged view of the teeth can be provided during use of the instrument.

  A sixth embodiment of the present invention is shown in FIG. 10, and its modifications are shown in FIGS. In FIG. 10, the light source element 13 is mounted on the end of the handle 11 together with a support structure 51 (such as a hard wire) and an optical element 52. Optical element 52 includes layers 53-56, layers 53 and 55 are non-reflective layers, layer 54 is an optical filter, and layer 56 is a mirror coating layer. A typical ray of light incident on element 52 is shown in FIG. At least some of the incident light I in this example is the fluorescence response of the body tissue of the light emitted from the element 13. Incident light I passes through filter 54 and is filtered so that the preferred wavelengths pass and others are absorbed. When the incident light beam I reaches the mirror coating 56, the light beam is reflected there and becomes reflected light R. The reflected light R again passes through the filter layer 54, and further unwanted wavelengths are attenuated and emitted outside the optical element 52, preferably entering the viewer's eyes. The non-reflective layers 53 and 55 reduce the attenuation of the observation light R due to internal reflection in the optical element 52.

  FIG. 11 shows another optical element 52 ', which includes layers 53-56 similar to those shown in FIG. However, in the optical element 52 ′, the light source element 13 is located behind the reflective layer 56, and due to the hole 57 (through the layers 53-56), the light source 13 causes the other part of the optical element 52 ′ to pass. Thus, the tissue to be examined can be reached. Tissue fluorescence (known in the art and described above) strikes the optical element 52 'as incident light I and is reflected as reflected light R, as shown in FIG. The hole 57 is a cylindrical hole and is perpendicular to the surface of the layer 53 through all the layers of the optical element 52 ′ at the center of the surface. In other embodiments, holes 57 may have other shapes and may be disposed at other positions and at different angles in optical element 52, as those skilled in the art will recognize. The electric wire for supplying energy to the light source element 13 passes through a conduit 58 located on the back surface of the optical element 52 '.

  Furthermore, another embodiment includes an optical element 52 '' as shown in FIG. In this embodiment, in addition to layers 53-56 (described in connection with FIG. 10), a wire 59 extends around the periphery of the optical element 52 ″, thereby via the support member 51. The light source element 13 is connected to a power source.

  11 and 12, energy for exciting the light source element 13 passes through the support member 51, and the light source element 13 is connected to a power source such as a battery compartment in the handle portion 11. In other embodiments, where necessary or preferred for these other appliances, power is supplied from an AC power source, with or without a transformer or rectifier.

  Those skilled in the art will appreciate that these mirror / filter combinations have substantial advantages over gold mirrors and separate filters. Regarding the former, the reflection at the gold mirror increases the red element, but does not aid in the observation of the green element, making it more difficult to diagnose. Furthermore, the mirror / filter combination of FIGS. 10-12 is easier to handle for the user than a typical mirror and separate filter.

  FIG. 13 shows the application of the present invention to dermatology. In the ninth embodiment, the stand 60 supports a loupe 62 that includes an LED ring on one side for irradiating the skin of the subject 64. The filter / magnifier 66 is located in the outer ring 62, thereby forming a window for the physician or technician to observe the skin lesion response to incident light from the LED. The support arm 68 is movable relative to the support member 60, which allows the observer to move the loupe to the necessary or preferred location for examination of the lesion.

  In the modification of the present embodiment, the support portion 60 is fixedly or movably connected to the inspection table, the wall surface, or the light source structure. In various forms of the invention, the support arm 68 can extend. Although the present invention has been described in terms of testing human subjects, the present invention is particularly effective when used for this purpose, but the present invention is not limited to other animals or plants, as would occur to those skilled in the relevant art. It can also be applied to organizations.

  In particular, some applications of the present invention are in the dermatological field. For example, the invention described and claimed herein can be used for cancer testing (both oral and skin cancer) and acne treatment.

  Although the geometric description of the shield herein applies to the inner surface of the shield, the contour and shape of the outer surface are useful in applying the present disclosure regarding aesthetic aspects and magnification. Further, in this specification, “cylindrical” means a traditional mathematical definition, “a. A surface formed by a linear trajectory moving parallel to a fixed straight line, Or a parallel plane across all elements and the space formed by the cylinder.

  It will be appreciated by those skilled in the art that the configurations described above can be combined with each other and / or with configurations disclosed in inspection applications. Those skilled in the art will be able to configure light source elements other than LEDs in other embodiments of the present invention.

  FIG. 14 shows a tenth embodiment of the present invention. This embodiment relates to a shield, mirror and filter arrangement suitable for inspection of dental structures and image capture in a controlled setting. In the present embodiment, the handle portion 61 is generally cylindrical, and its end is formed as a narrower end 63. A light source 65 and a camera hole 67 are formed at the end of the end 63. The former emits light of one or more wavelengths through the light source 65, and the latter (hole 67) receives light captured as an image. The aperture 67 may include a lens, one or more CCDs, and other elements for image capture as would occur to those skilled in the art. Similarly, light source 65 may include one or more light emitting diodes such as would occur to those skilled in the art.

  The light emitted by the light source 65 is transmitted through a hood 69, which generally has a cylindrical shape, and in a preferred embodiment is tapered so as to form a narrow end. . The light emitted from the light source 65 is reflected by the flat mirror 71 and reaches the observation point 73. This light induces autofluorescence in the dental tissue, returns through the observation point 73, is reflected by the mirror 71, is transmitted through the filter 75 before passing through the hole 67, and is captured as an image.

  In this preferred embodiment, the length of the hood 69, the structure of the mirror 71, the observation points 73 and the filter 75 allows the dental professional to continuously measure and position the device continuously to obtain a positioned image. You can see that you can. For example, an expert can place the observation point 73 directly on the tooth surface, thereby fixing a certain distance (from the bottom surface of the observation point 73 to the mirror 71, hole 67 during the image capture process). Distance). By using the apparatus and technique described in US Pat. No. 6,597,934, more accurate positioning can be achieved. In these example structures, the body of the hood is formed of an opaque material such as plastic, preventing substantially all of the surrounding light from entering and interfering with image capture at the hole 67. . In certain image capture scenarios, the patient can close his lips around the hood and in any case block substantially all light from affecting the image capture.

  In other embodiments, the hood 69 is disposable and is discarded after use for each patient. In another embodiment, a clear plastic cover is placed on the more permanent hood 69 and discarded after use. In still other embodiments, the hood 69 is permanently secured by the band piece 61, and in other embodiments, the hood 69 uses one or more attachment mechanisms known by those skilled in the mechanical arts. It is attached to the end of the handpiece 61 in a snap manner.

  In other embodiments, the optical filter 75 is omitted, and the image captured through the hole 67 is analyzed digitally and frequency portions below a certain threshold (eg, 520 nm or 580 nm) are removed. Image analysis is performed as described above.

  FIG. 15 shows the hand held light source and the distal end of the camera device, which includes a neck 81, a white LED 83, a blue LED 85, a camera hole 87 and an opaque distance retaining shield 89. The three-pole switch 91 of the neck 81 includes (1) a state in which all LEDs are off, (2) a state in which blue LEDs are on, and a yellow filter covers the inside of the hole 87, and (3) white LEDs. Is on, and the gray filter has three positions, covering the inside of the hole 87. Therefore, the specialist examines the patient using a white light source and a camera, and then obtains a fluorescent image of the patient's oral structure without moving the instrument from the patient's mouth to determine the condition of the teeth or other oral tissue. Can be diagnosed.

  While the invention has been described in detail in the drawings and foregoing description, it is to be understood that the invention is illustrative and not restrictive in nature, only the preferred embodiments are shown, It should be understood that modifications and alterations that have been described and that would occur to those of ordinary skill in the relevant art are protected. In addition, all patents, publications, prior and contemporaneous applications and other documents cited herein are each incorporated by reference and are incorporated by reference as if fully cited.

It is a perspective view of the instrument concerning the 1st example of the present invention. It is a side view of the instrument used in order to test | inspect the tooth | gear which concerns on 1st Example of this invention. It is a perspective view of the instrument which concerns on 2nd Example of this invention. It is a side view of the instrument used in order to test | inspect the tooth | gear which concerns on 2nd Example of this invention. It is a perspective view of the instrument based on 3rd Example of this invention. It is a side view of the instrument used in order to test | inspect the tooth | gear which concerns on 3rd Example of this invention. It is a side view of the instrument used in order to test | inspect the tooth | gear which concerns on 4th Example of this invention. It is a perspective view of the instrument used in order to test | inspect the tooth | gear which concerns on 5th Example of this invention. It is a side view of 5th Example of this invention. FIG. 9 is a side view of a device according to a sixth embodiment of the present invention, including an enlarged view of stacked optical elements according to the sixth embodiment of the present invention. It is a side view of the laminated | stacked optical element which concerns on 7th Example of this invention. It is a side view of the laminated | stacked optical element which concerns on 8th Example of this invention. It is a side view of the application in the dermatology field concerning the 9th example of the present invention. It is a partially cutaway side view of the hood / filter which concerns on 10th Example of this invention. It is a perspective view of the hood / filter which concerns on 11th Example of this invention.

Claims (61)

An instrument used to detect one or more abnormal tissue conditions,
One or more light sources that emit automatic fluorescence-induced light to the tissue;
An instrument with a shield located in the vicinity of one or more light sources and optically filtering light emitted by autofluorescence of tissue.   The instrument of claim 1, wherein the shield has a cylindrical shape.   The instrument of claim 2, wherein the shield has a regular cylindrical shape.   The instrument of claim 3, wherein the shield has a regular cylindrical shape.   The instrument of claim 2, wherein the shield has a cylindrical shape.   The instrument of claim 1, wherein the shield has a cone shape.   The instrument of claim 1, wherein the shield has a spherical shape.   The instrument of claim 1, wherein at least a portion of the shield expands so that a region of space within the shield can be observed from outside the shield.   The instrument of claim 1, wherein the mirror is within the shield and is positioned to reflect at least a portion of light emitted by autofluorescence of oral tissue.   The instrument of claim 1, wherein the shield filters visible light of a predetermined frequency, and the visible light is emitted by autofluorescence of oral tissue.   The apparatus of claim 1, wherein the one or more light sources are at least four and are located within the ring structure.   The apparatus of claim 11, wherein the number of the one or more light sources is at least six.   The instrument of claim 11, wherein the shield is a flat surface formed by a ring.   The instrument of claim 13, wherein the shield is substantially inserted in a plane formed by the ring.   The instrument of claim 13, wherein the shield comprises a magnifying lens.   The apparatus of claim 1, wherein the one or more light sources are light emitting diodes.   The instrument of claim 1, wherein the shield is treated to reduce haze.   The instrument of claim 1, wherein light passing through the shield is directly observed by a human.   The apparatus of claim 1 wherein light passing through the shield is captured by an image capture element.   The apparatus of claim 19, wherein the shield holds the image capture element at a predetermined distance from the object.   The instrument of claim 1, wherein the tissue is tooth tissue.   The device of claim 1, wherein the tissue is skin tissue.   The instrument of claim 1, wherein the one or more light sources and shields are secured to a case held by hand.   The instrument of claim 1, wherein the one or more light sources and shields are mechanically supported in a user selectable position.   The device of claim 1, wherein the tissue is human tissue.   The device of claim 1, wherein the tissue is dog tissue.   The device of claim 1, wherein the tissue is a cat tissue. One or more additional light sources used to illuminate the tissue with white light;
A switch that selectively enables one or more light sources used to emit automatic fluorescence-inducing light and one or more additional light sources used to emit white light The instrument of claim 1. An instrument used to detect one or more abnormal tissue conditions,
One or more light sources that emit automatic fluorescence-induced light to the tissue;
An instrument with a shield located in the vicinity of one or more light sources and optically filtering light emitted by autofluorescence of tissue.   30. The apparatus of claim 29, wherein the light emission of the light source element has a peak intensity at a wavelength between about 380 nm and about 500 nm.   30. The apparatus of claim 29, wherein the light emission of the light source element has a peak intensity at a wavelength between about 390 nm and about 450 nm.   30. The apparatus of claim 29, wherein the one or more light sources are integrated into the hand held unit and the shield is movably attached to the hand held unit.   30. The device of claim 29, wherein the light passing through the shield is observed directly by a human.   30. The apparatus of claim 29, wherein light passing through the shield is captured by an image capture element.   35. The apparatus of claim 34, wherein the shield holds the image capture element at a predetermined distance from the object.   30. The device of claim 29, wherein the shield does not substantially attenuate wavelengths of ambient light that do not induce autofluorescence of the tissue at at least one or more wavelengths of interest.   30. The appliance of claim 29, wherein the tissue is tooth tissue.   30. The tissue is dental tissue in the oral cavity, and the shield passes sufficient light through the oral cavity while one or more optical elements illuminate the oral cavity, thereby allowing visual observation of the oral cavity. The instrument described.   30. The device of claim 29, wherein the tissue is skin tissue.   30. The apparatus of claim 29, wherein the one or more light source elements and the shield are mounted on a hand-held case.   30. The apparatus of claim 29, wherein the one or more light sources and shields are mechanically supported in a user selectable position.   30. The device of claim 29, wherein the tissue is human tissue.   30. The device of claim 29, wherein the tissue is canine tissue.   30. The device of claim 29, wherein the tissue is a cat tissue. One or more additional light sources used to illuminate the tissue with white light;
A switch that selectively enables one or more light sources used to emit automatic fluorescence-inducing light and one or more additional light sources used to emit white light 30. The device of claim 29. An irradiation device that is used to examine body tissue for the presence or absence of tissue abnormalities;
A mirror having an optical filter layer,
The mirror substantially reflects the fluorescence emitted from the tissue toward the detection unit,
The optical filter layer is a system that effectively attenuates light of a wavelength that induces tissue fluorescence.   The system of claim 46, wherein the mirror magnifies fluorescence emitted from the tissue.   The system of claim 46, wherein the mirror has an anti-reflective coating. The mirror has a first anti-reflective coating layer,
A second anti-reflective coating layer;
An optical filter layer between the first antireflective coating layer and the second antireflective coating layer;
49. The system of claim 48, further comprising a mirror coating layer, wherein the second antireflective coating layer is between the optical filter layer and the mirror coating layer.   The system according to claim 46, wherein the detection unit is a human eye.   The system according to claim 46, wherein the detection unit is a camera.   47. The appliance of claim 46, wherein the tissue is dental tissue.   47. The device of claim 46, wherein the tissue is skin tissue.   The instrument of claim 46, wherein the shield is treated to reduce haze. The irradiation device comprises a plurality of light elements arranged as a ring,
The instrument of claim 46, wherein the mirror is disposed within the ring.   The apparatus of claim 46, wherein the illumination device comprises at least one light element that emits light having a peak intensity between about 380 nm and about 500 nm.   57. The apparatus of claim 56, wherein the at least one light element emits light having a peak intensity between about 390 nm and about 450 nm.   The instrument of claim 46, wherein the optical filter layer substantially attenuates light having a wavelength of about 520 nm or less.   59. The apparatus of claim 58, wherein the optical filter layer substantially attenuates light having a wavelength of about 580 nm or less.   47. The instrument of claim 46, wherein the mirror is integrated with the illumination device in a single housing.   The instrument of claim 46, wherein the mirror is removable from the irradiator.

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