Minolta Camera Kabushiki Kaisha

Minolta Company, Ltd.

Masami Sugiyama

Nobukazu Kawagoe

Masahito Inaba

Yoshihiro Tasaka

Satoshi Yokota

Yoshihiro Okui

Tomoko Miyaura

Takao Sakai

Nobuyuki Kita

Seiiku Ito

Takeshi Kosaka

Tohru Kisanuki

Shigeru Osaki

A two-dimensional colorimeter focuses light through a beam splitter onto a rotary filter so that a first light receiving element can receive light from multiple points on a sample. A rotating filter can provide multiple measurements based upon different wavelengths of light. A portion of the light from the beam splitter also contacts a spectral sensor which separates the light from a particular point into primary wavelength elements which are converted into electrical signals. Based upon these primary wavelength elements, the first signals from the light receiving element are corrected. As a result, the measurement of chromaticity of multiple points on a sample can be performed accurately using a device of simple construction.

Two-dimensional colorimeter

A spectrophotometer utilizes a band-pass filter array for splitting incident light into a plurality of light components of different wavelengths, a plurality of silicon photodiodes for receiving the respective light components, and a memory for storing spectral sensitivity information. The spectral sensitivity information is obtained by integrating the spectral sensitivities of spectrodetectors relative to each sectionalized wavelength regions sectionally generated from a measurement wavelength region. Each of the spectrodetectors include a band-pass filter array and a silicon photodiode in combination. A central processing unit calculates simultaneous equations representing the relation between the output from each of the silicon photodiodes, the spectral sensitivity information stored in memory and the light intensity of the sectionalized wavelength region, to obtain the light intensity.

Spectrophotometer for accurately measuring light intensity in a specific

A light sensor comprises optical filters, an interference filter and a photoelectric converting element which receives and photoelectrically converts light which has passed through the optical filters and the interference filter. An incident angle of the incident light on the interference filter can be changed so as to realize a desirable spectral sensitivity in a combination of the optical filters, the interference filter and the photoelectric converting element. The incident angle can be changed by a mounting structure that can rotate about an optical axis.

Light sensor with an adjustable spectral characteristic

A spectrophotometer utilizes a band-phase filter array for splitting incident light into a plurality of light components of different wavelengths, a plurality of silicon photodiodes for receiving the respective light components, and a memory for storing spectral sensitivity information. The spectral sensitivity information is obtained by integrating the spectral sensitivities of spectrodetectors relative to each sectionalized wavelength regions sectionally generated from a measurement wavelength region. Each of the spectrodetectors include a band-pass filter array and a silicon photodiode in combination. A central processing unit calculates simultaneous equations representing the relation between the output from each of the silicon photodiodes, the spectral sensitivity information stored in memory and the light intensity of the sectionalized wavelength region, to obtain the light intensity.

A colorimeter comprises a light source, a mixing box formed of non-coated light diffusing surface manufactured by molding sintering white ceramics or white resin for diffusing and reflecting light from the light source to guide the same to a sample, first light receiving means for receiving light reflected from the sample when light is emitted from the light source, and second light receiving means for receiving light other than the light reflected from the sample emitted from the light source.

Compact diffusion light mixing box and colorimeter

A spectral sensitivity correcting device in a photoelectric tristimulus colorimeter which comprises three light receiving systems for the measurement of tristimulus values. Signals indicative of respective outputs from two of the light receiving systems multiplied by predetermined correction coefficients are added to or subtracted from an output from the remaining light receiving system so that spectral sensitivity characteristics of the remaining light receiving system can approach predetermined spectral sensitivity characteristics.

Spectral sensitivity correcting device in a photoelectric tristimulus

A light measuring device wherein a correct measured value can be obtained even if incident light varies in time or a luminance or brightness of an object for measurement is insufficient. The device comprises a branched optical fiber of a random specification having therein three mutually independent light transmission paths for introducing light from a common input end to three output ends. The input end of the optical fiber is located at a slightly defocused position of an objective lens while the output ends are individually opposed to three light receiving elements having different spectral sensitivities. Three components of light are simultaneously converted into electric signals and then into digital values by circuit means each including a double integration analog to digital converter. When a luminance is insufficient at a light receiving element, the gain of the associated analog to digital converter can be adjusted so as to assure appropriate measurement of light.

Multi-channel spectral light measuring device

A color measuring apparatus including a photoelectric conversion device for outputting basic color signals corresponding to quantities of light of basic color components of a sample, respectively, a calculating device for calculating a color value of the sample in a predetermined colorimetric system, a target setting device for setting a target color value of the sample in the predetermined colorimetric system, a region setting device for setting a predetermined region containing the target color value, a region decision device for deciding whether or not the color value falls within the predetermined region, an approximation decision device for deciding whether or not the color value has most approximated to the target color value and an output device for outputting a result of the decision of the approximation decision device.

Color measuring apparatus

A spectral sensor comprises that a plurality of arrays of light receiving elements sensitive to different wavelength ranges which are arranged in a non-overlapping relationship with each other within the imaginary circle of a diameter smaller than the sum of lengths of the resective arrays of light receiving elements, and a filtering element of different transmission wavelength for each of the light receiving elements of all of the arrays, which filtering element is arranged in register with the respective light receiving element.

Spectral sensor with interference filter

A photoelectric colorimeter which comprises a photoelectric conversion section including an optical filter to analyze light coming from a test piece and a reference calibrating sample into primary color elements, and a photosensor to convert each of said primary color elements into an electric signal; and a data processing section including a calibration constant calculating device for calculating a calibration constant for each of a plurality of reference calibrating samples on the basis of a calibration point of each of the reference calibrating samples and an information inputted from said photoelectric conversion section, a chromaticity point calculation device for calculating a chromaticity point of the test piece and that of each reference calibrating sample, a memory device for memorizing the calibration constant and calibration point of each of the reference calibrating samples, a device for estimating a new calibration constant suitable for the chromaticity point of the test piece between the respective calibration constants of the reference calibrating samples through the interpolation using a positional relation between the chromaticity point of the calibration point and that of the test piece as a parameter, and a correction device for correcting measured value of the test piece by the new calibration constant.

Photoelectric colorimeter

A hand-carriable, compact color meter for indicating proper amount of adjustment of color compensation filters interposed in the light path of a color printer for the compensation of color balance of the light illuminating a film or the slide set on the printer. The color meter includes an indicating lamp, a photocell to be exposed to the light passing through the film or slide, a plurality of optical color filters selectively disposed in front of the photocell to provide the photocell with spectral sensitivities corresponding to the spectral sensitivity of the printing paper, a plurality of fixed or variable resistors selectable in correspondence to the selection of the color filter, and an electric circuit for actuating the indicating lamp in accordance with the relationship between the output of the light measuring circuit and a reference voltage commensurate with the selected one of the resistors. In a preferred embodiment, the color meter further includes a combination of a variable resistor and a filter for determination of exposure time.

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Toyonaka, Japan

Masami Sugiyama