Colorimeter and color measurement method

Abstract

The present application is applicable to the field of color measurement technology and provides a colorimeter and color measurement method. The colorimeter includes an integrating sphere, a continuous spectrum light source, a first color measurement device, and a diffuse reflection diaphragm. The integrating sphere is provided with a sampling aperture for aligning with a sample and a first detection aperture for allowing diffusely reflected light from the sample to pass through. The continuous spectrum light source is disposed opposite the interior space of the integrating sphere and is used to project continuous spectrum light into the interior of the integrating sphere. The first color measurement device is disposed opposite the first detection aperture and is used to receive diffusely reflected light from the sample at the sampling aperture and measure the intensity of the diffusely reflected light. The diffuse reflection diaphragm is disposed in contact with the inner wall of the integrating sphere and has notches at positions corresponding to the sampling aperture and the first detection aperture. The method can avoid the complex spraying steps of the diffuse reflection coating, simplify the manufacturing process, and reduce manufacturing costs. Furthermore, the method does not leave diffuse reflection material on the side walls of the sampling aperture and the first detection aperture, thereby improving the reproducibility of the colorimeter.

Description

Technical Field

[0001] The present application relates to the technical field of color measurement, and in particular to a colorimeter and a color measurement method. Background Art

[0002] A colorimeter is an instrument that measures the color of an object by reflecting light from it. For non-luminous, opaque objects, their color depends on the object's absorption and reflection of various wavelengths. In actual measurement, factors affecting the color measurement of an object depend not only on the object itself but also on the luminous spectrum of the light source, the performance parameters of the color sensor, and the relative position of the sample, light source, and color sensor—that is, the geometric conditions under which the colorimeter performs reflectance measurements. The CIE (Commission Internationale de l'Eclairage, International Commission on Illumination) specifies ten geometric conditions for reflectance measurement, one of which is the di:8° (Diffusion: 8°, Included, which includes specular components) geometric condition. The di:8° colorimeter includes a spherical segment of the integrating sphere. The bottom surface of the segment serves as the sampling aperture. The sample is aligned with the sampling aperture and receives uniform illumination from all directions on the inner surface of the integrating sphere. The measurement area is overfilled, and the detector response is uniform across the sampling aperture. The axis of the receiving beam forms an 8° angle with the normal to the sample center. Furthermore, the radiation reflected from the sampling aperture should be uniform in all directions within 5° of the receiving beam axis. This di:8° measurement method effectively eliminates the influence of the sample's surface structure, which is particularly important for color measurement of textured paper, metal, and textiles.

[0003] Achieving the di:8° geometric condition requires the use of an integrating sphere. Traditionally, the integrating sphere is made by first making a spherical shell out of metal or plastic, and then spraying a barium sulfate or magnesium oxide coating on the inner wall. This manufacturing process can easily lead to poor reproducibility of the colorimeter's measurement results, affecting the overall optical performance of the integrating sphere. Summary of the Invention

[0004] The purpose of this application is to provide a colorimeter to solve the technical problem of poor reproducibility of measurement results of traditional di:8° colorimeter.

[0005] The present application is implemented as follows: a colorimeter includes an integrating sphere, a continuous spectrum light source, a first color measuring device and a diffuse reflection diaphragm; the integrating sphere is provided with a sampling aperture for aligning with a sample, and a first detection aperture for allowing the diffuse reflection light of the sample to pass through; the continuous spectrum light source is arranged opposite to the internal space of the integrating sphere, and is used to project continuous spectrum light into the interior of the integrating sphere; the first color measuring device is arranged opposite to the first detection aperture, and is used to receive the diffuse reflection light of the sample at the sampling aperture and measure the intensity of the diffuse reflection light; the diffuse reflection diaphragm is arranged to fit the inner wall of the integrating sphere, and the diffuse reflection diaphragm is provided with notches at positions corresponding to the sampling aperture and the first detection aperture.

[0006] In one embodiment of the present application, the integrating sphere is further provided with a light entrance aperture for limiting the range of light spots that the continuous spectrum light source can directly illuminate within the integrating sphere. The continuous spectrum light source is arranged opposite the light entrance aperture, and the first detection aperture and the sampling aperture are arranged to avoid the area directly illuminated by the continuous spectrum light source through the light entrance aperture on the inner wall of the integrating sphere.

[0007] In one embodiment of the present application, the colorimeter further comprises a coupling lens for imaging the sample for measurement by the first color measurement device, wherein the coupling lens is disposed between the first color measurement device and the first detection aperture.

[0008] In one embodiment of the present application, the colorimeter further includes an even-light glass, which is disposed at a position where the coupling lens images the sample, and the first color measurement device is disposed opposite to the even-light glass.

[0009] In one embodiment of the present application, the colorimeter further comprises at least one imaging aperture, and the imaging aperture is arranged between the first color measurement device and the first detection aperture.

[0010] In one embodiment of the present application, the colorimeter further includes a first extinction tube for filtering out stray light, the first extinction tube connects the first color measurement device and the first detection aperture, and a stray light elimination structure is provided on the inner wall of the first extinction tube.

[0011] In one embodiment of the present application, the stray light elimination structure includes serrated stripes arranged around the inner wall of the first light extinction tube; the stray light elimination structure includes serrated protrusions arranged on the inner wall of the first light extinction tube.

[0012] In one embodiment of the present application, the colorimeter further includes a second color measuring device for measuring the intensity of reflected light from the diffuse reflection diaphragm, the integrating sphere further includes a second detection aperture, the second color measuring device is arranged opposite the second detection aperture, and the first detection aperture, the sampling aperture, and the light entrance aperture are arranged to avoid an area of ​​the inner wall of the integrating sphere that can be directly observed by the second color measuring device through the second detection aperture.

[0013] Another object of the present application is a color measurement method applicable to the colorimeter as described above, for measuring the reflectance value of a sample, comprising:

[0014] Obtaining calibration parameters: the colorimeter measures a standard sample and records the intensity of reflected light of the standard sample obtained by the first color measurement device when measuring the standard sample, and the intensity of reflected light of the diffuse reflection film obtained by the second color measurement device when measuring the standard sample;

[0015] Acquiring light intensity: the colorimeter receives the intensity of the reflected light of the diffuse reflection film acquired by the second color measuring device, and the intensity of the reflected light of the sample acquired by the first color measuring device;

[0016] Solving the sample reflectance: the colorimeter solves the light source attenuation rate of the continuous spectrum light source based on the reflected light intensity of the diffuse reflection film and the reflected light intensity of the sample, and corrects the reflected light intensity of the sample based on the light source attenuation rate.

[0017] In one embodiment of the present application, in the step of obtaining calibration parameters, the standard sample includes a standard whiteboard and a standard blackboard, and obtaining the calibration parameters specifically includes:

[0018] The colorimeter measures a standard white plate, and receives the intensity of reflected light of the standard white plate obtained by the first color measuring device, and the intensity of reflected light of the diffuse reflection film obtained by the second color measuring device when measuring the standard white plate;

[0019] The colorimeter measures the standard blackboard and receives the reflected light intensity of the standard blackboard obtained by the first color measuring device and the reflected light intensity of the diffuse reflection film obtained by the second color measuring device when measuring the standard blackboard.

[0020] A colorimeter implementing the present application has at least the following beneficial effects:

[0021] The inner wall of the integrating sphere is covered with a diffuse reflection diaphragm. Light emitted by the continuous spectrum light source, after striking the diffuse reflection diaphragm, is diffusely reflected to illuminate the entire interior of the integrating sphere, thereby illuminating the sample surface. The first color measurement device detects the intensity of the diffusely reflected light from the sample surface, thereby obtaining specific color parameters of the sample surface. By diffusely reflecting the light emitted by the continuous spectrum light source and illuminating the sample surface through the diffuse reflection diaphragm, the complex step of spraying a diffuse reflection coating can be avoided during the manufacturing process, thereby simplifying the manufacturing process of the integrating sphere and reducing the manufacturing cost of the colorimeter. Moreover, the shape of the diffuse reflection diaphragm corresponds to that of the spherical segment integrating sphere, with notches provided at the positions corresponding to the sampling aperture and the first detection aperture. Compared with a spray-on diffuse reflection layer, the diffuse reflection diaphragm does not leave diffuse reflection material on the sidewalls of the sampling aperture and the first detection aperture, thereby preventing light from directly irradiating the first color measurement device after being reflected from the sidewalls of the first detection aperture. This also improves the uniformity of the angular distribution of the light intensity irradiated on the surface of the measured sample, ultimately improving the reproducibility of the colorimeter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is a structural schematic diagram of a colorimeter provided by an embodiment of the present application;

[0024] Figure 2 yes Figure 1 A cross-sectional schematic diagram of the colorimeter shown in ;

[0025] Figure 3 yes Figure 2 A cross-sectional view of the colorimeter shown in FIG.

[0026] Figure 4 yes Figure 1 Schematic diagram of the working principle of the colorimeter shown in;

[0027] Figure 5 1 is a flow chart of a color measurement method provided by an embodiment of the present application.

[0028] The reference numerals used in the above drawings are as follows:

[0029] 11-Integrating sphere; 110-Diffuse reflection diaphragm; 111-Sampling aperture; 112-First detection aperture; 113-Light entrance aperture; 114-Second detection aperture; 12-Continuous spectrum light source; 131-First color measurement device; 132-Second color measurement device; 14-Coupling lens; 15-Homogeneous glass; 16-Imaging aperture; 161-First aperture; 162-Second aperture; 170-Stray light elimination structure; 171-First extinction tube; 172-Second extinction tube; 21-Sample; 3-Wireless connection module; 4-Power module; 5-Control module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0031] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly or indirectly located on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the accompanying drawings and are only for the convenience of description and cannot be understood as limitations on this technical solution. The terms "first" and "second" are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0032] In order to illustrate the technical solution described in this application, the following is a detailed description with reference to specific drawings and embodiments.

[0033] See also Figure 1 、 Figure 2 and Figure 4 This embodiment provides a colorimeter, including an integrating sphere 11, a continuous spectrum light source 12, a first color measuring device 131, and a diffuse reflection diaphragm 110; the integrating sphere 11 is provided with a sampling aperture 111 for aligning with a sample 2, and a first detection aperture 112 for allowing diffusely reflected light from the sample 2 to pass through; the continuous spectrum light source 12 is arranged opposite the interior space of the integrating sphere 11, and is used to project continuous spectrum light into the interior of the integrating sphere 11; the first color measuring device 131 is arranged opposite the first detection aperture 112, and is used to receive diffusely reflected light from the sample 2 at the sampling aperture 111 and measure the intensity of the diffusely reflected light; the diffuse reflection diaphragm 110 is arranged in contact with the inner wall of the integrating sphere 11, and has notches at positions corresponding to the sampling aperture 111 and the first detection aperture 112.

[0034] Specifically, the colorimeter provided in this embodiment works as follows:

[0035] See also Figure 3 The sampling aperture 111 is aligned with the sample 2, and the continuous spectrum light source 12 projects continuous spectrum light into the integrating sphere 11. The continuous spectrum light is diffusely reflected by the diffuse reflection film 110 attached to the inner wall of the integrating sphere 11, illuminating the entire interior space of the integrating sphere 11, thereby illuminating the surface of the sample 2. While illuminating the surface of the sample 2, the light is diffusely reflected again on the surface of the sample 2. Part of the diffusely reflected light passes through the first detection aperture 112 and is received by the first color measurement device 131 arranged opposite the first detection aperture 112. The first color measurement device 131 can obtain specific parameters of the surface color of the sample 2 through analysis based on the light intensity of the received diffusely reflected light.

[0036] The implementation of the colorimeter provided in this embodiment can achieve at least the following beneficial effects:

[0037] The inner wall of the integrating sphere 11 is covered by a diffuse reflection film 110. After the light emitted by the continuous spectrum light source 12 hits the diffuse reflection film 110, it is diffusely reflected to realize the illumination of the entire internal space of the integrating sphere 11, and then illuminates the surface of the sample 2. The first color measuring device 131 detects the light intensity of the diffuse reflection light on the surface of the sample 2, and the specific parameters of the surface color of the sample 2 can be obtained. By diffusely reflecting the light emitted by the continuous spectrum light source 12 through the diffuse reflection film 110 and realizing the illumination of the surface of the sample 2, the complicated spraying step of the diffuse reflection coating can be avoided during the production process, thereby simplifying the manufacturing process of the integrating sphere 11 and reducing The manufacturing cost of the colorimeter is reduced; moreover, the shape of the diffuse reflection diaphragm 110 corresponds to the shape of the spherical integrating sphere 11, in that notches are provided at positions corresponding to the sampling aperture 111 and the first detection aperture 112. Compared with the spray-on diffuse reflection layer, the solution using the diffuse reflection diaphragm 110 does not leave diffuse reflection material on the side walls of the sampling aperture 111 and the first detection aperture 112, thereby preventing light from being directly irradiated to the first color measurement device 131 after being reflected by the side walls of the first detection aperture 112, and also improving the uniformity of the angular distribution of the light intensity irradiated to the surface of the sample 2 to be measured, thereby ultimately improving the reproducibility of the colorimeter and the accuracy of the measurement results.

[0038] It should be noted that in the relevant technical field of colorimeters, reproducibility refers to the consistency of the measurement results obtained by the first color measurement device 131 when the sample 2 is aligned with the sampling aperture 111 while rotating about the center normal of the sampling aperture 111 and aligning with the first color measurement device 131 in different postures. A factor directly affecting reproducibility is the poor reproducibility of the convergent spot of the signal light irradiating the first color measurement device 131. Reproducibility is an important performance evaluation metric for colorimeters. If the signal light is affected by the colorimeter structure and contains interfering light signals, or if the surface of the object being measured is uneven and the angular distribution of the light intensity received by the sample 2 is uneven, the light intensity measurement results obtained by the first color measurement device 131 at different angles will vary when the sample 2 rotates about the center normal of the sampling aperture 111, resulting in large errors in the measurement results and poor reproducibility.

[0039] As a specific solution of this embodiment, the diffuse reflective diaphragm 110 is prepared through a thermoforming process. In this embodiment, the use of the thermoformed diffuse reflective diaphragm 110 replaces the diffuse reflective coating sprayed onto the inner wall of the integrating sphere 11 in the conventional solution. This simplifies the process and reduces the manufacturing cost of the colorimeter. It also prevents diffuse reflective material from being left on the sidewalls of the sampling aperture 111 and the first detection aperture 112. This prevents light from being directly reflected from the sidewalls of the first detection aperture 112 and irradiating the first color measurement device 131. This also improves the uniformity of the angular distribution of the light intensity irradiated on the surface of the measured sample 2 and the reproducibility of the convergent light spot, ultimately improving the reproducibility of the colorimeter and the accuracy of the measurement results.

[0040] As a preferred solution of this embodiment, the diffuse reflection film 110 adopts an anti-UV (Ultra Violet) film, that is, the diffuse reflection film 110 is provided with an anti-ultraviolet layer, which can prevent the ultraviolet rays in the continuous spectrum light source 12 from irradiating the sample 2, causing the sample 2 to emit fluorescence under the excitation of ultraviolet rays, affecting the accuracy of the detection results.

[0041] See also Figures 2 to 4In one embodiment of the present application, the integrating sphere 11 further includes a light entrance aperture 113 for limiting the range of the light spot that the continuous spectrum light source 12 can directly illuminate within the integrating sphere 11. The continuous spectrum light source 12 is positioned directly opposite the light entrance aperture 113, and the first detection aperture 112 and the sampling aperture are positioned to avoid the area directly illuminated by the continuous spectrum light source 12 through the light entrance aperture 113 on the inner wall of the integrating sphere 11. The light entrance aperture 113 serves to limit the boundaries of the continuous spectrum light spot directly projected by the continuous spectrum light source 12 on the inner wall of the integrating sphere 11, preventing the continuous spectrum light from being directly projected onto the sample 2. This reduces or even eliminates the specular reflection effect on the surface of the sample 2 and the fluorescence effect on the surface of the sample 2 under ultraviolet irradiation. It also avoids uneven angular distribution of light incident on the surface of the sample 2, ultimately improving the accuracy and reproducibility of the measurement results. It also prevents the continuous spectrum light from being directly projected onto the sidewalls of the detection aperture, preventing this portion of light from interfering with the optical signal received by the first color measurement device 131. It can be understood that since the colorimeter in this embodiment adopts the solution of disposing the diffuse reflection film 110 in the integrating sphere 11, compared with the traditional solution of spraying diffuse reflection paint on the inner wall of the integrating sphere 11, it can also achieve the effect of not leaving diffuse reflection material on the side walls of the light incident aperture 113, thereby preventing light from being reflected by the side walls of the light incident aperture 113 and affecting the color measurement results of the first color measurement device 131.

[0042] See also Figure 2 As a specific solution of this embodiment, the integrating sphere 11 comprises upper and lower hemispheres. The sampling aperture 111 is located at the bottom of the lower hemisphere; the first detection aperture 112 is located near the top of the upper hemisphere; the optical axis of the first color measurement device is arranged along the line connecting the center points of the sampling aperture 111 and the first detection aperture 112, and this line forms an 8° angle with the center normal of the sampling aperture 111; the light entrance aperture 113 is located at the junction of the upper and lower hemispheres. Preferably, the light entrance aperture 113 is located at the junction of the upper and lower hemispheres on the side where the center normal of the sampling aperture 111 is offset from the first detection aperture 112. This design can simplify the structure of the colorimeter, optimize its manufacturing process, and reduce its cost.

[0043] See also Figures 2 to 4 In one embodiment of the present application, the colorimeter further includes a coupling lens 14 for imaging the sample 2 for measurement by the first color measurement device 131. The coupling lens 14 is disposed between the first color measurement device 131 and the first detection aperture 112. The coupling lens 14 is used to couple the diffusely reflected light emitted by the sample 2 and can, to a certain extent, filter out light projected from other directions toward the first color measurement device 131, thereby improving the signal-to-noise ratio of the optical signal of the sample 2.

[0044] See also Figure 2 and Figure 3As a specific solution of this embodiment, the optical axis of the coupling lens 14 coincides with the line connecting the center point of the sampling aperture 111 and the center point of the first detection aperture 112, and the sample 2 is imaged on the homogenizing glass 15 for color measurement by the first color measurement device 131.

[0045] See also Figure 2 and Figure 3 In one embodiment of the present application, the colorimeter further includes a homogenizing glass 15, which is disposed at the position where the coupling lens 14 images the sample 2, and the first color measurement device 131 is disposed directly opposite the homogenizing glass 15. This can improve the uniformity of the color and light intensity of the light spot imaged by the coupling lens 14, thereby improving the stability of the light signal received by the first color measurement device 131 and eliminating the influence of different illumination at different positions on the sample 2 on the measurement reproducibility of the colorimeter.

[0046] See also Figure 2 and Figure 3 In one embodiment of the present application, the colorimeter further includes at least one imaging aperture 16 , which is disposed between the first color measurement device 131 and the first detection aperture 112 , and can further filter out stray light and prevent light other than the surface of the sample 2 from being received by the first color measurement device 131 .

[0047] See also Figure 2 and Figure 3 As a specific solution of this embodiment, the imaging aperture 16 includes a first aperture 161 and a second aperture 162. The second aperture 162 is attached to the surface of the homogenizing glass 15 facing the coupling lens 14 and is used to limit the size of the light spot formed on the homogenizing glass 15. The detection area of ​​the first color measurement device 131 is smaller than the light spot area on the homogenizing glass 15. This ensures that the first color measurement device 131 only receives diffusely reflected light from the sample 2. The first aperture 161 is located between the homogenizing glass 15 and the coupling lens 14 to eliminate stray light and prevent light from locations other than the sample 2 from interfering with the light signal received by the first color measurement device 131, thereby improving the measurement reproducibility of the colorimeter.

[0048] In one embodiment of the present application, the first color measurement device 131, the homogenizing glass 15, the second aperture 162, the first aperture 161, and the coupling lens 14 are coaxially arranged and arranged in sequence from far to near along a line connecting the center points of the sampling aperture 111 and the first detection aperture 112. The coupling lens 14 images the sample at the sampling aperture 111 onto the homogenizing glass 15. The second aperture 162 is attached to the homogenizing glass 15, limiting the field of view of the first color measurement device 131. The aperture size of the second aperture 162 is smaller than the size of the image of the sampling aperture 111 presented by the coupling lens 14, so that the entire field of view that can be observed by the first color measurement device 131 through the second aperture 162 falls within the sampling aperture 111. By setting the aperture size of the second aperture 162 to be smaller than the size of the image of the sampling aperture 111 presented by the coupling lens 14 on the homogenizing glass 15, the detection area of ​​the first color measurement device 131 for the sample 2 can be made smaller than the sampling aperture 111, ensuring that the optical signal of the first color measurement device 131 is not interfered with by the light reflected by the diffuse reflection diaphragm 110.

[0049] See also Figures 1 to 3 In one embodiment of the present application, the colorimeter further includes a first extinction tube 171 for filtering out stray light. The first extinction tube 171 connects the first color measurement device 131 and the first detection aperture 112. A stray light elimination structure 170 is provided on the inner wall of the first extinction tube 171. The stray light elimination structure 170 includes serrated stripes disposed around the inner wall of the first extinction tube 171. The stray light elimination structure 170 includes serrated protrusions disposed on the inner wall of the first extinction tube 171. The first extinction tube 171 is provided to filter out stray light outside the field of view of the first color measurement device 131, thereby reducing the impact of stray light signals on measurement results, thereby reducing measurement errors and improving the repeatability of measurement results.

[0050] As a preferred solution of this embodiment, the toothed stripes or toothed protrusions are coated with a color-reducing coating, which can further filter out stray light and reduce the influence of light signals outside the field of view of the first color measurement device 131 on the measurement results, thereby reducing measurement errors and improving measurement reproducibility.

[0051] See also Figures 1 to 4In one embodiment of the present application, the colorimeter further includes a second color measurement device 132 for measuring the intensity of light reflected from the diffuse reflective film 110. The integrating sphere 11 further defines a second detection aperture 114. The second color measurement device 132 is positioned directly opposite the second detection aperture 114. The first detection aperture 112, the sampling aperture, and the light entrance aperture 113 are positioned to avoid the area of ​​the inner wall of the integrating sphere 11 that the second color measurement device 132 can directly observe through the second detection aperture 114. The second color measurement device 132 is configured to receive and measure the diffusely reflected light from the diffuse reflective film 110, thereby obtaining the intensity of the light within the integrating sphere 11 and monitoring its changes in real time. The second color measurement device 132 then corrects the measurement results of the first color measurement device 131, thereby eliminating the effects of variations in the intensity of the light emitted by the continuous spectrum light source 12 and the color of the sample 2 on the measurement results of the first color measurement device 131. This eliminates the need for repeated debugging and calibration of the colorimeter during use.

[0052] As a specific solution of this embodiment, the first color measuring device 131 and / or the second color measuring device 132 uses a photodetector to respectively measure the light intensity values ​​of three colors in the reflected light intensity of the sample 2 and obtain the color of the sample 2 through calculation.

[0053] See also Figures 2 to 4 As a specific solution of this embodiment, the second color measurement device 132 and the continuous spectrum light source 12 are disposed on the same PCB board. This design facilitates optimization of the circuit layout of the colorimeter and eliminates the need for a separate optical path for the second color measurement device 132, thereby simplifying the structure of the colorimeter and reducing its cost. Furthermore, because the fields of view of both the second color measurement device 132 and the light source need to avoid the detection aperture 112 and the sampling aperture, changes in the light intensity of the continuous spectrum light source 12 can be conveniently monitored by the second color measurement device 132, and direct illumination of the continuous spectrum light source 12 from the second color measurement device 132 can be avoided. Preferably, the continuous spectrum light source 12 is disposed around the second color measurement device 132, and the light entrance aperture 113 is disposed around the second detection aperture 114; alternatively, the continuous spectrum light source 12 is evenly arranged around the second color measurement device 132, and the light entrance aperture 113 is evenly arranged around the second detection aperture 114. This can further improve the accuracy of the measurement results of the second color measurement device 132, thereby ensuring that the measurement results of the second color measurement device 132 correct the measurement results of the first color measurement device 131.

[0054] See also Figure 2 and Figure 4As a specific solution of this embodiment, the colorimeter also includes a second extinction tube 172 for filtering out stray light. The second extinction tube 172 connects the second detection aperture 114 and the second color measurement device 132. A stray light elimination structure 170 is provided on the inner wall of the second extinction tube 172. The stray light elimination structure 170 includes serrated stripes surrounding the inner wall of the first extinction tube 171. The stray light elimination structure 170 includes serrated protrusions provided on the inner wall of the first extinction tube 171. The second extinction tube 172 is provided to filter out stray light outside the field of view of the second color measurement device 132, reducing the impact of stray light signals on measurement results, thereby reducing measurement errors and improving measurement reproducibility.

[0055] See also Figure 1 and Figure 2 In one embodiment of the present application, the colorimeter further includes a standard sample, a wireless connection module 3, a power module 4, and a control module 5. The power module 4 is used to power the entire colorimeter and preferably includes a lithium battery and a charging port. The control module 5 directly drives the continuous spectrum light source 12 to emit light. The first color measurement device 131 and the second color measurement device 132 are connected to the control module 5. During measurement, the control module 5 first illuminates the continuous spectrum light source 12, then simultaneously collects the light intensity values ​​of the first color measurement device 131 and the second color measurement device 132. After the collection is completed, the continuous spectrum light source 12 is turned off to save power. The control module 5 calculates the reflectance value of the sample 2 based on the measured data and the calibration data stored in the control module 5, and finally converts it into a colorimetric value for display. The standard sample is fixed to the base of the instrument, making it convenient to calibrate the colorimeter at any time, avoiding errors caused by aging of optical components and sudden changes in ambient temperature, further improving accuracy. When calibration is required, simply close the base to the main housing, and the standard sample will fit snugly against the measurement port. The colorimeter then measures the standard sample and stores the measurement results in the control module 5. The wireless connection module 3 is preferably a Bluetooth connection module. The colorimeter is connected to the mobile phone via the Bluetooth connection module. The readings of various color chromaticities such as Lab, Luv, LCH, Yxy, CMYK, RGB, etc. can be realized through the mobile phone APP. Various color difference calculations such as △E*ab, △E*uv, △E*94, △E*cmc, △E*00, etc. can also be conveniently performed on the mobile phone.

[0056] Another object of the present application is a color measurement method applicable to the colorimeter as described above, for measuring the reflectance value of a sample 2, comprising:

[0057] Obtaining calibration parameters: The colorimeter measures the standard sample and records the intensity of the reflected light of the standard sample obtained by the first color measurement device 131 when measuring the standard sample, and the intensity of the reflected light of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring the standard sample;

[0058] Obtaining light intensity: The colorimeter receives the intensity of the reflected light of the diffuse reflection film 110 obtained by the second color measurement device 132 and the intensity of the reflected light of the sample 2 obtained by the first color measurement device 131;

[0059] Calculating the reflectivity of sample 2: The colorimeter calculates the light source attenuation rate of the continuous spectrum light source 12 based on the reflected light intensity of the diffuse reflection film 110 and the reflected light intensity of sample 2, and corrects the reflected light intensity of sample 2 based on the light source attenuation rate.

[0060] The color measurement method provided in this embodiment can achieve at least the following beneficial technical effects:

[0061] Because the optical environment inside integrating sphere 11 is complex after sample 2 is placed, and the spectrum of light emitted by continuous-spectrum light source 12 changes over time as conditions such as temperature change, there is a certain error between the reflectivity value of sample 2 measured by first color measurement device 131 and the actual reflectivity value of sample 2. Therefore, a second color measurement device 132 is introduced to correct the measurement results of first color measurement device 131 by monitoring the intensity changes of the continuous-spectrum light within integrating sphere 11 in various frequency bands in real time. Calibration parameters are obtained by measuring standard samples and used to compensate for the measurement values ​​obtained by first color measurement device 131. This double approximation greatly reduces the error in the colorimeter's measurement results for sample 2.

[0062] As a preferred solution of this embodiment, the control module 5 is provided with a memory structure for storing the calibration parameters obtained in the step of obtaining the calibration parameters.

[0063] In one embodiment of the present application, in the step of obtaining calibration parameters, the standard sample includes a standard whiteboard and a standard blackboard, and obtaining the calibration parameters specifically includes:

[0064] The colorimeter measures the standard white plate, receives the intensity of the reflected light of the standard white plate obtained by the first color measuring device 131, and the intensity of the reflected light of the diffuse reflection film 110 obtained by the second color measuring device 132 when measuring the standard white plate;

[0065] The colorimeter measures the standard blackboard, and receives the intensity of the reflected light of the standard blackboard obtained by the first color measuring device 131 and the intensity of the reflected light of the diffuse reflection film 110 obtained by the second color measuring device 132 when measuring the standard blackboard.

[0066] As a preferred solution of this embodiment, the control module 5 is provided with a memory structure for storing the reflected light intensity of the standard whiteboard obtained by the first color measurement device 131, the reflected light intensity of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring the standard whiteboard, the reflected light intensity of the standard blackboard obtained by the first color measurement device 131, and the reflected light intensity of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring the standard blackboard.

[0067] As a specific solution of this embodiment, the colorimeter corrects the light source attenuation rate. When continuous spectrum light passes through the diffuse reflection diaphragm 110 and illuminates the sampling aperture 111, some of the light is diffusely reflected by the sample 2 and then illuminates the diffuse reflection diaphragm 110. After diffuse reflection by the diffuse reflection diaphragm 110, it illuminates the second color measurement device 132. As a result, the light intensity detected by the second color measurement device 132 changes with the reflectivity of the measured sample 2. Correcting the light source attenuation rate helps further improve the accuracy of the color measurement results of the first color measurement device 131 on the sample 2.

[0068] The following is a specific example to illustrate the color measurement method provided by this embodiment and its technical effects:

[0069] See also Figure 5 In this embodiment, the color measurement method includes:

[0070] S1: Obtain calibration parameters: The colorimeter measures the standard white plate and receives the reflected light intensity I of the standard white plate obtained by the first color measurement device 131. 11 , and the reflected light intensity I of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring the standard white plate 21 , the reflectivity of the standard white plate is R1;

[0071] The colorimeter measures the standard blackboard and receives the reflected light intensity I of the standard blackboard obtained by the first color measuring device 131. 12 , and the reflected light intensity I of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring the standard blackboard 22 , the reflectivity of the standard blackboard is R2;

[0072] S2: Obtaining light intensity: The colorimeter measures sample 2, receives the reflected light intensity I1 of sample 2 obtained by the first color measurement device 131, and obtains a preliminary color measurement result R0 of sample 2 (i.e., the uncorrected color detection result of sample 2), as well as the reflected light intensity I2 of the diffuse reflection film 110 obtained by the second color measurement device 132 when measuring sample 2;

[0073] S3: Calculating the reflectivity of sample 2: The colorimeter calculates the light source attenuation rate of the continuous spectrum light source 12 based on the reflected light intensity of the diffuse reflection film 110 and the reflected light intensity of sample 2, and corrects the reflected light intensity of sample 2 based on the light source attenuation rate.

[0074] Specifically, solving the reflectivity of sample 2 includes:

[0075] The colorimeter corrects the light source attenuation rate A, specifically:

[0076]

[0077] Where h is the influence coefficient, R0 is the uncorrected color test result of sample 2, specifically:

[0078]

[0079]

[0080] The final reflectivity value of sample 2 is:

[0081]

[0082] The complex optical environment within integrating sphere 11 after sample 2 is placed affects the colorimetric results of first color measurement device 131. For example, as temperature and other conditions change, the spectrum of light emitted by continuous-spectrum light source 12 also varies over time, resulting in a certain error between the reflectivity value of sample 2 measured by first color measurement device 131 and the actual reflectivity of sample 2. Furthermore, when the continuous-spectrum light passes through diffuse reflection diaphragm 110 and strikes sampling aperture 111, some of the light is diffusely reflected by sample 2 and then strikes diffuse reflection diaphragm 110, where it is then diffusely reflected by diffuse reflection diaphragm 110 and strikes first color measurement device 131, resulting in a certain error in the measurement results of first color measurement device 131. Therefore, second color measurement device 132 is introduced to correct for the error in the continuous-spectrum light emitted by continuous-spectrum light source 12, while also correcting for the error in first color measurement device 131 caused by the diffuse reflection of sample 2. Combining these two factors, the measurement results of first color measurement device 131 are corrected and compensated. This double approximation significantly reduces the error in the colorimetric instrument's measurement results of sample 2.

[0083] It should be understood that this embodiment provides the most complete color measurement method. In actual use, multiple measurements can be performed after the colorimeter obtains the calibration parameters. That is, in actual use, the light intensity acquisition step and the reflectance calculation step of sample 2 can be performed multiple times after the calibration parameter acquisition step, without the need to perform a calibration before each measurement of the color of sample 2.

[0084] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A colorimeter, characterized in that: include: an integrating sphere, the integrating sphere being provided with a sampling aperture for aligning with a sample and a first detection aperture for allowing diffusely reflected light of the sample to pass through; a continuous spectrum light source, the continuous spectrum light source being arranged facing the interior space of the integrating sphere and being used to project continuous spectrum light into the interior of the integrating sphere; a first color measurement device, the first color measurement device being disposed opposite the first detection aperture and configured to receive diffusely reflected light from the sample at the sampling aperture and measure the intensity of the diffusely reflected light; a diffuse reflection diaphragm, the diffuse reflection diaphragm being arranged in contact with the inner wall of the integrating sphere, the shape of the diffuse reflection diaphragm corresponding to the shape of the integrating sphere, and the diffuse reflection diaphragm having notches at positions corresponding to the sampling aperture and the first detection aperture; The colorimeter further includes a coupling lens for imaging the sample for measurement by the first color measurement device, the coupling lens being disposed between the first color measurement device and the first detection aperture; the colorimeter further includes an even-light glass disposed at a position where the coupling lens images the sample, and the first color measurement device is disposed directly opposite the even-light glass; The colorimeter further includes at least one imaging aperture, the imaging aperture including a first aperture and a second aperture, the second aperture being attached to a surface of the homogenizing glass facing the coupling lens, the detection area of ​​the first color measurement device being smaller than the spot area on the homogenizing glass, and the first aperture being disposed between the homogenizing glass and the coupling lens; The integrating sphere is further provided with a light entrance aperture for limiting the range of a light spot that can be directly illuminated by the continuous spectrum light source within the integrating sphere. The colorimeter further includes a second color measurement device for measuring the intensity of light reflected from the diffuse reflection diaphragm. The integrating sphere is further provided with a second detection aperture, the second color measurement device is arranged directly opposite the second detection aperture, and the first detection aperture, the sampling aperture, and the light entrance aperture are arranged to avoid an area of ​​the inner wall of the integrating sphere that can be directly observed by the second color measurement device through the second detection aperture. The colorimeter further includes a control module, which is provided with a memory structure for storing the reflected light intensity of the standard white board obtained by the first color measurement device, the reflected light intensity of the diffuse reflection film obtained by the second color measurement device when measuring the standard white board, the reflected light intensity of the standard black board obtained by the first color measurement device, and the reflected light intensity of the diffuse reflection film obtained by the second color measurement device when measuring the standard black board; the colorimeter is also used to correct the light source attenuation rate using the following formula: in, A is the light source attenuation rate, h is the influence coefficient, R 0 is the uncorrected sample color detection result, R 1 is the reflectivity of a standard white board, R 2 is the reflectivity of the standard blackboard, I 1 is the intensity of the reflected light of the sample obtained by the first color measurement device, I 2 is the intensity of reflected light of the diffuse reflection film obtained by the second color measurement device when measuring the sample, I 11 The reflected light intensity of the standard white plate obtained by the first color measurement device, I 21 is the intensity of reflected light of the diffuse reflection film obtained by the second color measurement device when measuring the standard white plate, I 22 is the intensity of reflected light from the diffuse reflection film obtained by the second color measurement device when measuring the standard blackboard; Finally, the reflectivity value of the sample is obtained R for: 。 2. The colorimeter according to claim 1, wherein: The continuous spectrum light source is arranged opposite to the light incident aperture, and the first detection aperture and the sampling aperture are arranged to avoid an area on the inner wall of the integrating sphere that is directly irradiated by the continuous spectrum light source through the light incident aperture.

3. The colorimeter according to claim 1, wherein The colorimeter further includes a first extinction tube for filtering out stray light, the first extinction tube is connected to the first color measuring device and the first detection aperture, and a stray light elimination structure is provided on an inner wall of the first extinction tube.

4. The colorimeter according to claim 3, wherein: The stray light elimination structure includes tooth-shaped stripes arranged around the inner wall of the first light extinction tube; the stray light elimination structure includes tooth-shaped protrusions arranged on the inner wall of the first light extinction tube.

5. A color measurement method, characterized in that: A colorimeter for measuring the reflectance of a sample, suitable for use with the colorimeter according to any one of claims 1 to 4, comprising: Obtaining calibration parameters: the colorimeter measures a standard sample and records the intensity of reflected light of the standard sample obtained by the first color measurement device when measuring the standard sample, and the intensity of reflected light of the diffuse reflection film obtained by the second color measurement device when measuring the standard sample; Acquiring light intensity: the colorimeter receives the intensity of the reflected light of the diffuse reflection film acquired by the second color measuring device, and the intensity of the reflected light of the sample acquired by the first color measuring device; Solving the sample reflectance: the colorimeter solves the light source attenuation rate of the continuous spectrum light source based on the reflected light intensity of the diffuse reflection film and the reflected light intensity of the sample, and corrects the reflected light intensity of the sample based on the light source attenuation rate.

6. The color measurement method according to claim 5, wherein: In the step of obtaining calibration parameters, the standard samples include a standard whiteboard and a standard blackboard, and obtaining calibration parameters specifically includes: The colorimeter measures a standard white plate, and receives the intensity of reflected light of the standard white plate obtained by the first color measuring device, and the intensity of reflected light of the diffuse reflection film obtained by the second color measuring device when measuring the standard white plate; The colorimeter measures the standard blackboard, receives the reflected light intensity of the standard blackboard obtained by the first color measuring device, and the reflected light intensity of the diffuse reflection film obtained by the second color measuring device when measuring the standard blackboard.

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