X-rite Gmbh

Garrison Dental Solutions LLC

Target Telemetrics, LLC

Mark A Cargill

Bernard J Berg

Steven Henry Peterson

Douglas V Baker

Thomas J Boes

David R Bowden

James L Mourey

Stephen B Rankin

Robert L Winchester

Gary T Kalinka

Timothy R Friend

Patrick S Rood

Peter G VanderJagt

William R Given

Kenneth A Round

The specification discloses a dental curing light including 1) a light engine, 2) a coaxially aligned, camera-based viewing system, and 3) a control system providing a variety of safety features and simplified, operator-friendly operation. The camera's field of view (FOV) is coaxial with the centerline of the curing beam of the light engine. The curing light includes a multi-planar dichroic mirror (MDM) providing viewing and light beam direction aligned with the target. The MDM provide multiple images to the camera from different angles. The camera provides real-time measurement of light intensity reflected back from the targeted surface. Using the multiple image portions reflected by the multi-planar dichroic mirror, the control system computes the distance between the curing light and the target. The reflected intensity and the calculated distance enable the control system to compute a light engine irradiance to achieve a desired irradiance at the targeted surface.

Dental curing light and method

Gun target

A color measurement system includes a hand held color measurement instrument, which may be provided with a wireless interface to a computer. The color measurement system includes a scanning guide for holding the hand held color measurement instrument in proper alignment with a color target. The scanning guide includes a calibration reference to allow convenient calibration of the hand-held color measurement instrument. The hand-held color instrument includes an illumination ring to provide visual feedback to the user. The color of the illumination ring changes in order to display a color similar to that being read by the hand-held color measurement instrument. Color management profiling of the hand held color measurement instrument illumination ring improves the color rendition capability of the illumination ring.

Method for operating a color measurement system

Color measurement system

An LED-based color measurement instrument including an illumination system and a sensing system. The illumination system includes modulated LEDs and a temperature control system for regulating the temperature of the LEDs, thereby improving the consistency of their performance. The sensing system includes a photodiode, a transimpedance amplifier, and an integrator in the first stage to cancel the effect of ambient light on the output of the first stage. The sensing system also includes a lens system for imaging a target area of the target sample onto the photo sensor in a manner so that the product of the target area times the solid angle captured by the lens system is generally uniform over a selected range of distances, thereby reducing the positional sensitivity of the instrument with respect to the target sample.

Color measurement instrument

A portable spectrophotometer includes a rotating wheel provided with a plurality of filters having filter characteristics in the 400 to 700 nanometer wavelength range. The filters are moved between an optical conduit and a photoelectric sensor as the wheel is rotated. In one embodiment, a lamp housing contains three object illuminating lamps circumferentially spaced apart by 120.degree. and projecting light onto the object sample at a 45.degree. angle to the object sample. Light reflected from the object sample is conducted through the optical conduit and focused on the optical sensor by means of a focusing lens. A blocking filter is interposed between the lens and the wheel and serves to block light outside of the 400 to 700 nanometer wavelength range. A side sensor receives light from one of the three lamps through the filters as the wheel is rotated and provides output signals which are used as reference signals for the individual filters. In another embodiment, the spectrophotometer includes an integrating sphere with an aperture for conducting specular-included light reflected from the object and an aperture for conducting specular-excluded light from the object. The integrating sphere spectrophotometer also includes a rotatable filter wheel, with a plurality of filters having filter characteristics in the 400 to 700 nanometers wave length range. A side sensor is also provided with the integrating sphere spectrophotometer. As the wheel is rotated, specular-included and specular-excluded light from an object sample to be tested is projected simultaneously through apertures of the sphere. Light detected by a side sensor is also simultaneously detected through one of the filters of the filter wheel. The integrating sphere spectrophotometer also includes an arrangement for providing calibration and compensation of reflectance measurements.

Compact spectrophotometer

A spectrophotometer apparatus (200) is adapted to provide spectral reflectance measurements of object samples. The apparatus (200) comprises a source light (254) and a reflection optics assembly (264, 268). Signals representative of reflected light are analyzed and data provided to an operator representative of the spectral response characteristics of the object sample (252). The apparatus (200) further comprises a side sensor (276) having a fixed spectral response characteristic for compensating the reflectance measurements in accordance with the light intensity emanating from the lamp. For purposes of calibration, a series of time-sequenced measurements are made of a reference sample. Utilizing these measurements, the apparatus (200) provides computations of compensation coefficients for each spectral segment. The compensation coefficients are utilized, with the side sensor measurements, to provide normalization of the reflectance measurements for each segment and for each measurement within the timed sequence. For each segment, a scale factor is then determined. The scale factors, compensation coefficients and side sensor measurements are employed to compensate actual reflectance measurements, with further compensation provided by a determination of temperature coefficients.

Apparatus and method for calibration in a spectrophotometer

A spectrophotometer apparatus (200) is adapted to provide spectral reflectance measurements of an object sample (236) under test, particularly optical characteristics of colored surfaces comprising metallic or pearlescent particles. The apparatus (200) comprises a source light (226) and a reflection optics assembly. Signals representative of reflected light are analyzed and data is generated representative of the spectral response characteristics of the object sample (236). The apparatus (200) employs a plurality of fiber optic bundles (248, 250, 252) for receiving light reflected from the object sample (236), with each of the fiber optic bundles (248, 250, 252) being positioned at one of a corresponding plurality of fixed angles different from the angle of illumination of the source light (226). Reflectance is measured at each angle by sequential switching such that light is impaired from being received by all but a subset of the plurality of multiple angles. Light received from the fiber optic bundles is transferred to a single array of integral interference-filter/photodiode devices (284) which modulate the light and determine the spectral characteristics thereof. With the use of fiber optic devices, a single source of illumination and a single optical detector arrangement, the spectrophotometer apparatus (200) is employed within an optimally small packaging configuration, and the apparatus (200) can be maintained in a portable mode while maintaining relatively high accuracy and repeatability.

Multiangular color measuring apparatus

A portable spectrophotometer includes a small-diameter optical sphere as well as optical detectors and signal processing and display circuitry which allows the instrument to be taken to an object to be measured and which provides a readout of color values at the portable instrument. The instrument is capable of providing specular-included and specular-excluded color readings simultaneously. The interior of the integrating sphere is coated with a highly reflective, color-absorbing material, and light from an incandescent lamp is diffused within the sphere prior to reaching the object to be measured. The sphere is provided with a first aperture which receives spectrally-included light and which is positioned to absorb a spectral component of the diffused source light. A second aperture positioned at a corresponding angular position with respect to the object measures specular-excluded light, excluding the specular component absorbed by the first aperture. Light detected from the first aperture is analyzed at a plurality of wavelengths obtained by the use of interference filters, and the light obtained from the second aperture is analyzed at one of the plurality of wavelengths. By appropriately combining the specular-included and specular-excluded at one wavelength, a value for the specular component is derived. Since this value is a theoretical constant, it is used to derive a specular-excluded reading from each of the specular-included readings at the different wavelengths.

Portable spectrophotometer

A densitometer apparatus (410) is disclosed and is adapted to provide color density measurements of object samples. The densitometer apparatus (410) comprises a source light (580) for projecting light toward an object sample comprising a control strip (588, 620). A reflection optics assembly (576) is adapted to measure light density reflected from the object sample when the object sample is in the form of a paper control strip. A transmission optics assembly (618) is adapted to measure transmission density of light rays projected through the object sample when the object sample is in the form of a film control strip. A motor assembly (426) operating with a drive wheel assembly (434) and idler wheel assembly (440) automatically moves the object sample (588, 620) through the apparatus (410) adjacent the source light (580). A pair of guides (468, 470) are selectively adjustable by the operator to control movement of the object sample (588, 620) through the apparatus (410). In response to input from a key switch assembly (492) activatable by the operator, the apparatus (410) is adapted to perform various color density measurement and calibration functions, and display appropriate information to the operator through the use of a visual display (490).

Automated strip reader densitometer

A densitometer apparatus (200) is disclosed and is adapted to provide color density measurements of opaque materials. The densitometer apparatus (200) comprises a light source unit (202) having a source light (204) projecting light through a collimating lens (206). Light rays transmitted through the collimating lens (206) project through an aperture (208). The rays are projected onto an irradiated area surface of an object sample (212) under test. Electromagnetic radiation in the form of reflected light rays (214) are reflected from the sample (212). The reflected light rays are directed through a spectral filter apparatus (216) and impinge on receptor surfaces of photo-voltaic sensor cells (232, 234, 236). The sensors (232, 234, 236) generate electrical currents having magnitudes proportional to the intensities of the sensed light rays. The electrical signals are applied as input signals to amplifiers (244, 246, 248), with the amplified signals applied as input signals to a multiplexer (256) for time multiplexing each of the output signals from the amplifiers. The resultant multiplexed signal is applied as an input signal to an A/D converter (264) to convert the analog multiplexed signal to a digital signal. The digital output signal from the A/D converter (264) is applied as a parallel set of binary information signals to a central processing unit (266). Actual measurements of color reference patches are processed so as to solve for unknown constants of a set of equations representing correction or compensation factors functionally dependent on actual reflectance measurements. The correction factors are then utilized by the densitometer apparatus (200) to compensate measurements of actual object samples.

Growing community of inventors

Belding, MI, United States of America

Mark A Cargill