Lens module

Abstract

The invention provides a lens module which comprises a liquid crystal module, a color wheel and an image sensor. The liquid crystal module includes a first electrode layer, a second electrode layer, and a liquid crystal layer disposed between the first electrode layer and the second electrode layer. The color wheel is arranged on one side of the liquid crystal module and comprises a first light filtering area, a second light filtering area and a third light filtering area. The first filtering area comprises a first metasurface used for enabling a red light wave band to penetrate through, the second filtering area comprises a second metasurface used for enabling a green light wave band to penetrate through, and the third filtering area comprises a third metasurface used for enabling a blue light wave band to penetrate through. The color wheel is arranged between the liquid crystal module and the image sensor.

Description

Technical Field

[0001] The invention relates to an imaging device, and in particular to a lens module. Background Art

[0002] With the development and popularization of the optical field, the market's requirements for lens modules are becoming more and more stringent. While requiring better image quality and high color saturation, the weight, assembly difficulty and cost of the device must also be reduced accordingly. However, the performance of current lens modules still needs to be improved. Summary of the invention

[0003] The present invention is directed to a lens module, which can have higher image quality, reduce the weight and assembly complexity of the lens module, and improve the versatility of the lens module.

[0004] One embodiment of the present invention provides a lens module, including a liquid crystal module, a color wheel and an image sensor. The liquid crystal module includes a first electrode layer, a second electrode layer and a liquid crystal layer arranged between the first electrode layer and the second electrode layer. The color wheel is arranged on one side of the liquid crystal module and includes a first filter area, a second filter area and a third filter area. The first filter area includes a first metasurface for allowing a red light band to pass through, the second filter area includes a second metasurface for allowing a green light band to pass through, and the third filter area includes a third metasurface for allowing a blue light band to pass through. The color wheel is arranged between the liquid crystal module and the image sensor.

[0005] In the lens module of an embodiment of the present invention, a color wheel is arranged between the image sensor and the liquid crystal module, and the color wheel includes a plurality of filter zones of different filter bands. By utilizing the characteristic that the liquid crystal module can be used as an optical switch, the liquid crystal module can control the passage of light beams in different zones. Then, the plurality of filter zones can correspond to different zones to receive the aforementioned light beams passing through. Since the metasurfaces of different filter zones have different refractive indices and transmittances for light beams of different bands, different filter zones can effectively filter and focus light beams of different bands (or colors) onto the image sensor, and the image sensor can sequentially sense images of light of different bands, and these images of light of different bands can synthesize color images, so the image sensor can further sense color images with higher color saturation.

[0006] In addition, in the lens module of the present invention, since a color wheel is used to filter out light of different wavelength bands in sequence, a lens group and image sensor with a simpler structure can be used, thereby effectively reducing the assembly complexity of the lens module, and facilitating the lightweight of the lens module, thereby improving the versatility of the lens module. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a three-dimensional schematic diagram of a lens module according to an embodiment of the present invention;

[0008] Figure 2 yes Figure 1 Schematic diagram of imaging between a color wheel and an image sensor;

[0009] Figure 3A and Figure 3B Graphs of the microstructure and transmittance of the first filter region versus wavelength, respectively;

[0010] Figure 4A and Figure 4B are graphs of the microstructure and transmittance of the second filter region versus wavelength;

[0011] Figure 5A and Figure 5B They are respectively the microstructure and transmittance versus wavelength curves of the third filter zone;

[0012] Fig. 6A and Figure 6B They are respectively the microstructure and transmittance versus wavelength curves of the fourth filter zone;

[0013] Fig. 7A and Figure 7B They are respectively the microstructure and transmittance versus wavelength curves of the fifth filter zone;

[0014] Fig. 8A and Figure 8B are graphs of the microstructure and transmittance of the sixth filter zone versus wavelength;

[0015] Fig.9A and Fig. 9B They are respectively the microstructure and transmittance versus wavelength curves of the seventh filter zone;

[0016] Fig. 10A and Fig. 10B They are respectively the microstructure and transmittance versus wavelength curves of the eighth filter zone;

[0017] Fig.11 is a three-dimensional schematic diagram of a lens module according to another embodiment of the present invention;

[0018] Fig.12 FIG. 4 is a perspective schematic diagram of a lens module according to another embodiment of the present invention. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0020] Figure 1 is a three-dimensional schematic diagram of a lens module according to an embodiment of the present invention, Figure 2 yes Figure 1 Schematic diagram of the imaging between the color wheel and the image sensor. Figure 1 and Figure 2 The lens module 10A of this embodiment includes a liquid crystal module 110, a color wheel 120A, an image sensor 130, and a lens group 140. The liquid crystal module 110 includes a first electrode layer 111, a second electrode layer 112, and a liquid crystal layer 113 disposed between the first electrode layer 111 and the second electrode layer 112. The color wheel 120A is disposed on a side of the liquid crystal module 110 facing the image sensor 130, and includes a first filter area 121, a second filter area 122, a third filter area 123, a fourth filter area 124, a fifth filter area 125, a sixth filter area 126, a seventh filter area 127, and an eighth filter area 128. The color wheel 120A and the image sensor 130 are disposed on opposite sides of the lens group 140. Specifically, the color wheel 120A is disposed between the liquid crystal module 110 and the image sensor 130; and the lens group 140 is disposed between the color wheel 120A and the image sensor 130.

[0021] The liquid crystal module 110 may also include polarizers, a driving circuit, a pixel circuit, and an alignment layer (all not shown) disposed on opposite sides to realize the optical switch function of the liquid crystal module 110, and the present invention does not impose any restrictions on this. The liquid crystal module 110 can control the amount of light, thereby indirectly affecting the external ambient light beam (for example, Figure 2 The bias voltage applied by the first electrode layer 111 and the second electrode layer 112 can drive the arrangement of the corresponding liquid crystal molecules in the liquid crystal layer 113 to adjust the transmittance of the image beam IB, thereby realizing the control of the light flux of different areas on the liquid crystal module 110. When an electric field is applied, the liquid crystal molecules rotate under the influence of the electric field, and also change the proportion of light passing through, so that the brightness of pixels in different areas of the liquid crystal module 110 can be controlled.

[0022] During the operation of the lens module 10A, the color wheel 120A remains stationary relative to the liquid crystal module 110, the lens group 140 and the image sensor 130. That is, compared to the operation mode of rotating the color wheel in different time sequences in a general projector, the positions of the filter areas 121-128 on the color wheel 120A in this embodiment do not rotate during the image capture process of the lens module 10A. It is worth mentioning that each filter area 121-128 is a different metasurface structure to deflect and filter light beams of different wavelengths. For example, the first filter area 121 includes a first metasurface MF1 for allowing the red light band to pass through, the second filter area 122 includes a second metasurface MF2 for allowing the green light band to pass through, and the third filter area 123 includes a third metasurface MF3 for allowing the blue light band to pass through. In addition, in this embodiment, these metasurfaces MF1 to MF8 can be attached to a transparent substrate 120S, and the transparent substrate 120S is, for example, a glass or plastic plate in a circular shape.

[0023] Further, Figure 2 For example, the fourth filter zone 124 of the color wheel 120A includes a fourth metasurface MF4 for allowing the yellow light band to pass through, and the fifth filter zone 125 of the color wheel 120A includes a fifth metasurface MF5 for allowing the orange light band to pass through. Similarly, the sixth filter zone 126 of the color wheel 120A includes a sixth metasurface MF6 for allowing the purple light band to pass through. In addition, corresponding to different imaging fields or applications, the seventh filter zone 127 of the color wheel 120A can be an ultraviolet light filter zone, which includes a seventh metasurface MF7 for allowing the ultraviolet light band to pass through. And the eighth filter zone 128 can be an infrared light filter zone, including an eighth metasurface MF8 for allowing the infrared light band to pass through. In this embodiment, the first filter zone 121 to the eighth filter zone 128 are arranged in a ring shape around the central axis of the color wheel 120A.

[0024] It is particularly noted that in this embodiment, the first metasurface MF1 to the eighth metasurface MF8 are a new type of interface based on "metasurface" technology. Unlike traditional lenses that rely on curved surfaces to deflect light, metasurfaces manipulate the path of light through tiny nanostructures on the surface to achieve the effect of focusing and controlling the transmittance of different wavelengths. These nanostructures can accurately control the phase, amplitude and polarization of light, so the first metasurface MF1 to the eighth metasurface MF8 can filter and focus light of different wavelengths with extremely high precision, and can even process ultraviolet light and infrared light at the same time.

[0025] The lens module 10A can collect external ambient light and image the external image beam IB on the image sensor 130 to form an image IMG. The image sensor 130 then converts the image IMG into an electrical signal to transmit or store image data. The image sensor 130 can be, for example, a charge-coupled device (CCD) and a complementary metal oxide semiconductor active pixel sensor (CMOS Active pixel sensor), but is not limited thereto.

[0026] When the lens module 10A captures an image, the pixels on the liquid crystal module 110 that overlap different filter regions can be turned on accordingly. Figure 2 In the embodiment, the pixel area of ​​the liquid crystal module 110 overlapping the fourth filter area 124 of the color wheel 120A can be turned on, thereby allowing the image light beam IB from the outside to pass through and be transmitted to the fourth filter area 124, and then the image light beam IB is filtered by the fourth filter area 124 of the color wheel 120A into a light of a specific wavelength band (in this embodiment, for example, a yellow light wavelength band, but not limited thereto), and then the light filtered into the specific wavelength band is converged to the lens group (shown in FIG. Figure 1 The light is then focused to the image sensor 130 through the lens group 140 to form an image IMG. Similarly, the liquid crystal module 110 can open pixels at different positions at different timings through an electrically connected control circuit (not shown), so that different filter areas allow light of different wavelengths to be imaged on the image sensor 130 in sequence. By recording the control circuit (not shown) electrically connected to the image sensor 130 and used to process the signal of the image sensor 130, it is possible to analyze the images of different wavelengths sensed by the image sensor 130 at different times (for example, the red light wavelength image filtered by the first filter area 121, the green light wavelength image filtered by the second filter area 122, and the blue light wavelength image filtered by the third filter area 123, but not limited thereto), and then obtain the information of the color image synthesized by these images of different wavelengths.

[0027] In this way, after the liquid crystal module 110 and the color wheel 120A sequentially allow the image light beams IB of different wavelengths to be circulated and imaged on the image sensor 130, the lens module 10A can obtain complete color image information. The images of these different wavelengths of light can be synthesized into a color image, so the image sensor 130 can then sense a color image with a higher color saturation. Furthermore, since the metasurface can be adjusted according to light of different wavelengths, each wavelength can be accurately focused on a different position of the image sensor 130. After combining with the color wheel 120A, different colors of light can be effectively separated and focused, which can improve the color accuracy and contrast of the picture when the lens module 10A is shooting, so as to achieve accurate multi-spectral imaging.

[0028] In addition, the microstructure design of the first metasurface MF1 to the eighth metasurface MF8 can effectively reduce the thickness of the lens group 140, the number of internal lenses used, and the complexity of the curved surface design. The combination with the color wheel 120A can also replace the required multi-layer filter, reduce the volume and device complexity of the lens group 140, and thus facilitate the assembly, lightweight and miniaturization of the lens module 10A. It is suitable for use in smartphone cameras, medical imaging equipment, augmented reality equipment, virtual reality equipment, etc.

[0029] Furthermore, after being combined with the color wheel 120A, the lens module 10A does not need to rely on traditional optical refractive elements or optical path architectures to obtain color imaging, thereby reducing optical distortion, field curvature or aberration, and further optimizing imaging clarity and image light path.

[0030] Figure 3A and Figure 3B They are the microstructure and transmittance versus wavelength curves of the first filtering area. Figure 4A and Figure 4B They are the microstructure and transmittance versus wavelength curves of the second filtering area. Figure 5A and Figure 5B The graphs of the microstructure and transmittance of the third filter zone versus wavelength are shown in Figure 2. FIG. 3A to FIG. 5B , the first metasurface MF1 includes a plurality of first microstructures M1, the second metasurface MF2 includes a plurality of second microstructures M2, the third metasurface MF3 includes a plurality of third microstructures M3, P1 is the period of the plurality of first microstructures M1, P2 is the period of the plurality of second microstructures M2, and P3 is the period of the plurality of third microstructures M3. In this embodiment, the period P1, the period P2, and the period P3 may satisfy the following condition: P1>P2>P3. In this embodiment, the material of the first microstructure M1, the second microstructure M2, and the third microstructure M3 (as well as the fourth microstructure M4, the fifth microstructure M5, the sixth microstructure M6, the seventh microstructure M7, and the eighth microstructure M8 described later) may be gallium nitride (GaN) and may be cylindrical in appearance, and the ratio of the height to the diameter of the cylinder may be greater than 0.3 and less than 5, but the present invention is not limited thereto. The first to third microstructures M1 to M3 (and the fourth to eighth microstructures M4 to M8 described below) can be arranged on the transparent substrate 120S in a rectangular array. The material of the transparent substrate 120S can be glass (BK7) and the thickness can be 1 mm, but the present invention is not limited to this.

[0031] like Figure 3AAs shown, in detail, in this embodiment, the period P1 (or pitch) of the first microstructure M1 can be about 660 nanometers (nm); the diameter D1 of the first microstructure M1 can be greater than or equal to 450nm and less than or equal to 500nm; the height H1 of the first microstructure M1 can be greater than or equal to 300nm and less than or equal to 500nm. Figure 3B Therefore, the first metasurface MF1 of the first filter region 121 can have a higher transmittance to the red light band (eg, electromagnetic waves with a wavelength of 620nm to 700nm). For example, the transmittance of the first metasurface MF1 to the red light band can be greater than 70%.

[0032] For example Figure 4A As shown, in detail, in this embodiment, the period P2 (or pitch) of the second microstructure M2 can be about 500 nanometers (nm); the diameter D2 of the second microstructure M2 can be greater than or equal to 300nm and less than or equal to 400nm; the height H2 of the second microstructure M2 can be greater than or equal to 300nm and less than or equal to 500nm. Figure 4B Therefore, the second metasurface MF2 of the second filter region 122 can have a higher transmittance to the green light band (eg, electromagnetic waves with a wavelength of 495nm to 570nm). For example, the transmittance of the second metasurface MF2 to the green light band can be greater than 80%.

[0033] For example Figure 5A As shown, in detail, in this embodiment, the period P3 (or pitch) of the third microstructure M3 can be about 450 nanometers (nm); the diameter D3 of the third microstructure M3 can be greater than or equal to 300nm and less than or equal to 400nm; the height H3 of the third microstructure M3 can be greater than or equal to 300nm and less than or equal to 500nm. Figure 5B Therefore, the third metasurface MF3 of the third filter region 123 can have a higher transmittance to the blue light band (eg, electromagnetic waves with a wavelength of 450nm to 495nm). For example, the transmittance of the third metasurface MF3 to the blue light band can be greater than 80%.

[0034] Fig. 6A and Figure 6B The graphs of the microstructure and transmittance of the fourth filter zone versus wavelength are shown below. Fig. 6A In this embodiment, the fourth filter region 124 may include a plurality of fourth microstructures M4, and the period P4 (or pitch) of the fourth microstructures M4 may be about 550 nanometers (nm); the diameter D4 of the fourth microstructures M4 may be greater than or equal to 400nm and less than or equal to 450nm; the height H4 of the fourth microstructures M4 may be greater than or equal to 300nm and less than or equal to 500nm. Figure 6BTherefore, the fourth metasurface MF4 of the fourth filter region 124 can have a higher transmittance to the yellow light band (eg, electromagnetic waves with a wavelength of 570nm to 590nm). For example, the transmittance of the fourth metasurface MF4 to the yellow light band can be greater than 80%.

[0035] Fig. 7A and Figure 7B The graphs of the microstructure and transmittance of the fifth filter zone versus wavelength are shown below. Fig. 7A In this embodiment, the fifth filter region 125 may include a plurality of fifth microstructures M5, and the period P5 (or pitch) of the fifth microstructures M5 may be about 600 nanometers (nm); the diameter D5 of the fifth microstructures M5 may be greater than or equal to 400nm and less than or equal to 450nm; the height H5 of the fifth microstructures M5 may be greater than or equal to 300nm and less than or equal to 500nm. Figure 7B Therefore, the fifth metasurface MF5 of the fifth filter region 125 can have a higher transmittance to the orange light band (eg, electromagnetic waves with a wavelength of 590nm to 620nm). For example, the transmittance of the fifth metasurface MF5 to the orange light band can be greater than 70%.

[0036] Fig. 8A and Figure 8B The graphs of the microstructure and transmittance of the sixth filter zone versus wavelength are shown in Figure 1. Fig. 8A In this embodiment, the sixth filter region 126 may include a plurality of sixth microstructures M6, and the period P6 (or pitch) of the sixth microstructures M6 may be approximately 370 nanometers (nm); the diameter D6 of the sixth microstructures M6 may be greater than or equal to 200 nm and less than or equal to 400 nm; the height H6 of the sixth microstructures M6 may be greater than or equal to 300 nm and less than or equal to 500 nm. Figure 8B Therefore, the sixth metasurface MF6 of the sixth filter region 126 can have a higher transmittance to the ultraviolet band (eg, electromagnetic waves with a wavelength of 400nm to 450nm). For example, the transmittance of the sixth metasurface MF6 to the ultraviolet band can be greater than 80%.

[0037] Fig.9A and Fig. 9B The graphs of the microstructure and transmittance of the seventh filter zone versus wavelength are shown below. Fig.9A In this embodiment, the seventh filter region 127 may include a plurality of seventh microstructures M7, and the period P7 (or pitch) of the seventh microstructure M7 may be about 200 nanometers (nm); the diameter D7 of the seventh microstructure M7 may be greater than or equal to 200nm and less than or equal to 300nm; the height H7 of the seventh microstructure M7 may be greater than or equal to 300nm and less than or equal to 400nm. Fig. 9BTherefore, the seventh metasurface MF7 of the seventh filter region 127 can have a higher transmittance to ultraviolet light (eg, electromagnetic waves with a wavelength of 100 nm to 400 nm). For example, the transmittance of the seventh metasurface MF7 to ultraviolet light can be greater than 70%.

[0038] Fig. 10A and Fig. 10B The graphs of the microstructure and transmittance of the eighth filter zone versus wavelength are shown below. Fig. 10A In this embodiment, the eighth filter region 128 may include a plurality of eighth microstructures M8, and the period P8 (or pitch) of the eighth microstructures M8 may be approximately 660 nanometers (nm); the diameter D8 of the eighth microstructures M8 may be greater than or equal to 450nm and less than or equal to 600nm; the height H8 of the eighth microstructures M8 may be greater than or equal to 300nm and less than or equal to 500nm. Fig. 10B Therefore, the eighth metasurface MF8 of the eighth filter region 128 can have a higher transmittance to the infrared light band (for example, electromagnetic waves with a wavelength of 700nm to 1000nm). For example, the transmittance of the eighth metasurface MF8 to the infrared light band can be greater than 80%.

[0039] Therefore, in mobile phone camera modules and professional photography cameras, the design of the lens module 10A combined with the liquid crystal module 110, the first metasurface MF1 to the eighth metasurface MF8 and the color wheel 120A will help improve color reproduction and detail performance, and meet the current camera module requirements for lightweight and high resolution. It is worth mentioning that although this embodiment shows an implementation method in which the color wheel 120A has eight filter zones, it is not limited to this. In other embodiments, the number or area ratio of the filter zones can also be increased or decreased to adapt to different filter effects and application fields, and achieve better color performance.

[0040] Some other embodiments will be listed below to explain the present invention in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the aforementioned embodiments and will not be repeated below.

[0041] Fig.11 FIG. 1 is a perspective diagram of a lens module according to another embodiment of the present invention. Fig.11The lens module 10B is similar to the aforementioned lens module 10A, and the main difference is that the number of filter zones is different. Specifically, the color wheel 120B of the lens module 10B may only include the aforementioned first filter zone 121, the second filter zone 122, the third filter zone 123, and the ultraviolet filter zone, i.e., the aforementioned seventh filter zone 127. As described above, the lens module 10B can not only have the imaging effect of the three primary colors, but also be used to capture images in the ultraviolet band for application in special photography scenes (such as astronomical photography or exposure process inspection, etc.).

[0042] Fig.12 FIG. 1 is a perspective diagram of a lens module according to another embodiment of the present invention. Fig.12 The lens module 10C is similar to the aforementioned lens module 10A, and the main difference is that the number of filter zones is different. In detail, the color wheel 120C of the lens module 10C may only include the aforementioned first filter zone 121, the second filter zone 122, the third filter zone 123 and the infrared filter zone, i.e., the aforementioned eighth filter zone 128. Through the above, the lens module 10C can not only have the imaging effect of the three primary colors, but also can be used to capture images in the infrared light band for application in special photography scenes (such as thermal sensing cameras or infrared light communication sensing fields, etc.).

[0043] In summary, in the lens module of the embodiment of the present invention, the color wheel is arranged between the image sensor and the liquid crystal module, and the color wheel includes a plurality of filter zones of different filter bands. By utilizing the characteristic that the liquid crystal module can be used as an optical switch, the liquid crystal module can control the passage of light beams in different zones. Then, the plurality of filter zones can respectively correspond to different zones to receive the aforementioned light beams passing through. Since the metasurfaces of different filter zones have different refractive indices and transmittances for light beams of different bands, different filter zones can effectively focus light beams of different bands (or colors) onto the image sensor, and the image sensor can sequentially sense and image the images of light beams of different bands. These images of light of different bands can synthesize color images, so the image sensor can further sense color images with higher color saturation.

[0044] In addition, in the lens module of the present invention, since a color wheel is used to filter out light of different wavelength bands in sequence, a lens group and image sensor with a simpler structure can be used, thereby effectively reducing the assembly complexity of the lens module, and facilitating the lightweight of the lens module, thereby improving the versatility of the lens module.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lens module, characterized in that: include: A liquid crystal module, comprising a first electrode layer, a second electrode layer, and a liquid crystal layer arranged between the first electrode layer and the second electrode layer; A color wheel, arranged on one side of the liquid crystal module, comprises: A first light filtering region, comprising a first metasurface for allowing red light to penetrate; A second filter region, comprising a second metasurface for allowing green light to pass through; and A third light filtering region, comprising a third metasurface for allowing blue light to pass through; and The image sensor is provided with the color wheel between the liquid crystal module and the image sensor.

2. The lens module according to claim 1, characterized in that: The invention also comprises a lens group, which is arranged between the color wheel and the image sensor.

3. The lens module according to claim 1, characterized in that: The color wheel further includes a transparent substrate, and the first Metasurface, the second Metasurface and the third Metasurface are arranged on the transparent substrate.

4. The lens module according to claim 1, characterized in that: The color wheel also includes: a fourth filtering region, comprising a fourth metasurface for allowing yellow light to pass through; and The fifth filtering zone includes a fifth metasurface for allowing orange light to penetrate.

5. The lens module according to claim 4, characterized in that: The color wheel also includes a sixth filter area, including a sixth metasurface for allowing the violet light band to penetrate.

6. The lens module according to claim 1, characterized in that: The first metasurface includes a plurality of first microstructures, the second metasurface includes a plurality of second microstructures, and the third metasurface includes a plurality of third microstructures, and the following condition is satisfied: P1>P2>P3, wherein P1 is a period of the plurality of first microstructures, P2 is a period of the plurality of second microstructures, and P3 is a period of the plurality of third microstructures.

7. The lens module according to claim 1, characterized in that: The color wheel also includes an ultraviolet light filtering area, including a metasurface for allowing ultraviolet light bands to penetrate.

8. The lens module according to claim 1, characterized in that: The color wheel also includes an infrared light filtering area, including a metasurface for allowing infrared light bands to penetrate.

9. The lens module according to claim 1, characterized in that: The transmittance of the first metasurface in the red light band is greater than 70%.

10. The lens module according to claim 1, characterized in that: The transmittance of the second metasurface in the green light band is greater than 80%.

11. The lens module according to claim 1, characterized in that: The transmittance of the third metasurface for the blue light band is greater than 80%.

Images