US-20260126323-A1 - COLOR SENSOR AND COLOR SENSING DEVICE USING THE SAME

US20260126323A1US 20260126323 A1US20260126323 A1US 20260126323A1US-20260126323-A1

Abstract

A color sensing device including a color sensor and a processing unit is provided. The color sensor is provided with at least three photosensitive areas and used for generating at least three photosensitive signals. The processing unit is connected to the color sensor and used for processing the at least three photosensitive signals to correspondingly generate at least three color signal tuples CIE(X,Y,Z). Two of the at least three color signal tuples CIE(X,Y,Z) share one of the photosensitive signals.

Inventors

I-Chen Chien
Ruitao Zheng

Assignees

LITE-ON TECHNOLOGY CORPORATION
LITE-ON SINGAPORE PTE. LTD.

Dates

Publication Date: 20260507
Application Date: 20260105
Priority Date: 20220310

Claims (10)

1 . A color sensor used for converting a spectral function into color coordinates on a CIE (International Commission on Illumination) color space, wherein the color sensor comprises: a semiconductor chip provided with a plurality of photosensitive areas; and three filters correspondingly disposed on three of the photosensitive areas and used for defining three spectral functions of three stimulus values on the CIE color space, wherein the spectral functions of stimulus values X 1 and Z on the CIE color space share one of the filters, wherein the spectral function of stimulus value Z is represented by the spectral function of stimulus value X 1 , or the spectral function of the stimulus value X 1 is represented by the spectral function of stimulus value Z, or the spectral function of stimulus value Z and the spectral function of stimulus value X 1 are represented by the spectral function of stimulus value (X 1 +Z)/2, respectively.
2 . The color sensor according to claim 1 , wherein the three photosensitive areas and the three filters comprise: a first photosensitive area covered by a first filter is used for providing a first photosensitive signal, corresponding to a red light spectral function of stimulus value X 2 on the CIE color space; a second photosensitive area covered by a second filter is used for providing a second photosensitive signal, corresponding to a green light spectral function of stimulus value Y on the CIE color space; a third photosensitive area covered by a third filter is used for providing a third photosensitive signal, corresponding to a blue light spectral function of stimulus value Z on the CIE color space; and the blue light spectral function of stimulus value Z of the third filter modulates a required response rate k to generate a new spectral function X 1 ′=kZ corresponding to a blue light spectral function of stimulus value X 1 .
3 . The color sensor according to claim 1 , wherein the three photosensitive areas and the three filters comprise: a first photosensitive area covered by a first filter is used for providing a first photosensitive signal, corresponding to a red light spectral function of stimulus value X 2 on the CIE color space; a second photosensitive area covered by a second filter is used for providing a second photosensitive signal, corresponding to a green light spectral function of stimulus value Y on the CIE color space; a third photosensitive area covered by a third filter is used for providing a third photosensitive signal, corresponding to a blue light spectral function of stimulus value X 1 on the CIE color space; and the blue light spectral function of stimulus value X 1 of the third filter modulates a required response rate n to generate a new spectral function Z′=nX 1 corresponding to a blue light spectral function of stimulus value Z.
4 . The color sensor according to claim 1 , wherein the three photosensitive areas and the three filters comprise: a first photosensitive area covered by a first filter is used for providing a first photosensitive signal, corresponding to a red light spectral function of stimulus value X 2 on the CIE color space; a second photosensitive area covered by a second filter is used for providing a second photosensitive signal, corresponding to a green light spectral function of stimulus value Y on the CIE color space; a third photosensitive area covered by a third filter is used for providing a third photosensitive signal, corresponding to a blue light spectral function of stimulus value (X 1 +Z)/2 on the CIE color space; and the blue light spectral function of stimulus value (X 1 +Z)/2 of the third filter modulates required response rates k and n to generate two new spectral functions X 1 ′=k(X 1 +Z)/2 and Z′=n(X 1 +Z)/2 corresponding to a blue light spectral function of stimulus value X 1 and a blue light spectral function of stimulus value Z respectively.
5 . The color sensor according to claim 1 , wherein five filters correspondingly disposed on five of the photosensitive areas, wherein the three of the filters are used for generating three spectral functions of three stimulus values on the CIE color space, and the other two filters are used for generating auxiliary spectral functions, a spectral function of stimulus value X 1 and a spectral function of stimulus value Z of the three spectral functions share a same filter.
6 . A color sensing device, comprising: a color sensor implemented on a chip and used for generating at least three photosensitive signals, which indicate a color of incident light of the color sensor; a processing unit implemented on the chip, connected to the color sensor, and used for processing the at least three photosensitive signals to generate four channel signals; a control unit connected to the processing unit and used for receiving and processing the four channel signals to generate three sets of color signal tuples CIE(X,Y,Z) (International Commission on Illumination), wherein a spectral function of stimulus value Z is represented by a spectral function of stimulus value X 1 , or the spectral function of the stimulus value X 1 is represented by the spectral function of stimulus value Z, or the spectral function of stimulus value Z and the spectral function of stimulus value X 1 are represented by a spectral function of stimulus value (X 1 +Z)/2, respectively; and an interface connected to the processing unit, wherein the interface comprises an interface terminal.
7 . The color sensing device according to claim 6 , wherein the color sensor comprises a first photodiode configured to generate a first photosensitive signal; a second photodiode configured to generate a second photosensitive signal; and a third photodiode configured to generate a third photosensitive signal.
8 . The color sensing device according to claim 7 , wherein the processing unit is configured to process the first, the second and the third photosensitive signals to generate four channel signals within the RGB waveband; two of the four channel signals within a blue light waveband share one of the photosensitive signals.
9 . The color sensing device according to claim 7 , wherein the color sensor is covered by an infrared light blocking filter; and the first, the second and the third photodiodes are respectively covered by red light, green light and blue light filters.
10 . The color sensing device according to claim 6 , wherein five filters correspondingly disposed on five of the photosensitive areas, wherein three of the filters are used for generating three spectral functions of three stimulus values on a CIE color space, and the other two filters are used for generating auxiliary spectral functions, the spectral function of stimulus value X 1 and the spectral function of stimulus value Z of the three spectral functions share a same filter.

Description

This application is a Divisional application of U.S. patent application Ser. No. 18/118,552 filed on Mar. 7, 2023, which claims the benefit of People's Republic of China application Serial No. 202210231258.7 that was filed on Mar. 10, 2022, the subject matter of which is incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The invention relates in general to a light sensor, and more particularly to a color sensor and a color sensing device using the same. Description of the Related Art Refer to FIG. 1 and FIG. 2. In FIG. 1, three colors stimulus values are represented with X, Y and Z using a color overlay model; the three stimulus values are exported parameters of red, green, and blue colors and are used for defining human eyes' feeling with respect the different wavelengths of a visible light. In 1931, International Commission on Illumination (CIE) conducted a color matching experiment using color stimulus values of the three primary colors (red light, green light, and blue light) and obtained a color space using RGB as unit vectors; meanwhile, a CIE 1931 XYZ color space using three color stimulus values as chromaticity coordinates was constructed as indicated in FIG. 2. Thus, through the calculation on the CIE color space, after the three color stimulus values of human eyes with respect to a reflective object are converted to color coordinates on the CIE color space, so that the color of the reflective object (or the color temperature) can be obtained. Normally, the color sensor (or the color temperature sensor) includes three channels X, Y and Z respectively used for detecting the spectral function of the light projected to different photosensitive areas. The filter coating of the channel X is used for defining the channel X1 (the wavelength is about 442 nm). As for the color stimulus values of two wavebands in the channel X2 (the wavelength is about 599 nm), since the light is projected on the coating of the same photosensitive area, the formula of optical coating needs to be accurately adjusted. In the coating process, the wavelength, the bandwidth and the response rate of crests of two wavebands are difficult to control. Thus, the interpretation accuracy of conventional color sensor regarding the color temperature of an object has an error of ±25%, which needs to be resolved. SUMMARY OF THE INVENTION The invention is directed to a color sensor used for simplifying the formula of optical coating, the difficulty of manufacturing process and the color temperature correction process of the sensor, and completing the color coordinates on the CIE color space and the interpretation of color temperature to increase the interpretation accuracy of the color sensor. According to one embodiment of the present invention, a color sensing device is provided. The color sensing device includes a color sensor and a processing unit. The color sensor is provided with at least three photosensitive areas and used for generating at least three photosensitive signals. The processing unit is connected to the color sensor and used for processing the at least three photosensitive signals to correspondingly generate at least three color signal tuples CIE(X,Y,Z). Two of the color signal tuples CIE(X,Y,Z) share one photosensitive signal. According to another embodiment of the present invention, a color sensor is provided. The color sensor is used for converting a spectral function into color coordinates on the CIE color space. The color sensor includes a semiconductor chip and three filters. The semiconductor chip is provided with several photosensitive areas. The three filters are correspondingly disposed on three of the photosensitive areas and used for defining three spectral functions of three stimulus values on the CIE color space, wherein the spectral functions of stimulus values X1 and Z on the CIE color space share one of the filters. According to an alternate embodiment of the present invention, a color sensing device is provided. The color sensing device includes a color sensor, a processing unit, a control unit and an interface. The color sensor is implemented on a chip and used for generating three photosensitive signals, which indicate the color of each incident light of the color sensor. The processing unit is implemented on the chip, connected to the color sensor, and used for processing three photosensitive signals to generate four channel signals. The control unit is connected to the processing unit and used for receiving and processing four channel signals to generate three sets of color signal tuples CIE(X,Y,Z). The interface is connected to the processing unit, and includes an interface terminal. The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS F