Light sensor device
By introducing multi-channel filters into the photo sensor device, the problem that the photo sensor in the prior art requires multiple photo sensors is solved, the device is miniaturized and cost-reduced, and the response consistency of the photodiode sensor to different wavelengths of light is improved.
Patent Information
- Application Number
- CN202410363157.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-28
- Filing Date
- 2024-03-28
- Publication Date
- 2025-07-04
AI Technical Summary
Existing photo sensor devices require multiple photo sensors to process light of different wavelengths, making it difficult to miniaturize the device and increase manufacturing costs, and cannot effectively eliminate noise light.
The multi-channel filter design is adopted, and multiple channels are formed on a single photodiode sensor through optical coating technology to filter light at different wavelengths respectively to ensure that the photo sensor has the same response value to different target wavelengths.
Further miniaturization and cost reduction of the photo sensor device is achieved, while effectively eliminating noise light, ensuring that the photodiode sensor has a uniform response to light of different wavelengths.
Smart Images
Figure CN120264943A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a photosensor device, and more particularly to a photosensor device with a multi-channel filter for use in wearable devices or handheld devices. Background Art
[0002] In recent years, non-invasive photosensor devices (especially wearable or handheld photosensor devices) have been widely used in people's daily lives due to requirements such as motion recording, health management, and disease detection to provide users with various physiological information (e.g., heart rate, blood oxygen saturation, blood pressure, blood glucose, etc.).
[0003] In order to obtain different physiological information, the photosensor devices of the prior art require multiple light sources to generate light of different target wavelengths (e.g., green light, red light, and near-infrared light, with a wavelength range of 300 - 1100 nm), and are paired with multiple photosensors (e.g., photodiode sensors) to receive light of different target wavelengths. Generally, green light is used to measure the heartbeat, and red light and near-infrared light are used to measure blood oxygen saturation.
[0004] In addition, light sources with a light wavelength range of 300 - 1100 nm are also practically applied to the camera module in mobile phones, and their ambient light sensors also require multiple light sources to generate light of different target wavelengths and multiple photosensors to receive light of different target wavelengths. The ambient light sensor detects the physical flicker of ambient light (light generated by 3C devices (TVs, computers, mobile phones)) to provide an image correction input to eliminate stripes and artifacts caused by ambient light flicker and avoid distortion of the captured images and / or videos.
[0005] Under this architecture of the prior art, the photosensor device cannot use only a single photosensor to receive all the light, which makes it difficult to exclude ambient light in the range of 350 - 800 nm (e.g., sunlight, indoor light, and light generated by 3C devices), which is regarded as noise. Secondly, the response values of a single photosensor to green light, red light, and near-infrared light are different, with green light being the weakest and near-infrared light being the strongest, showing a gradient increase, resulting in a large gap in the response values of the three light sources. Therefore, it is difficult for the photosensor device to use only a single photosensor to process light with different response values to define measurement values of different wavelengths. Accordingly, the prior art cannot reduce the number of photosensors required for the photosensor device, so it is difficult to further miniaturize the photosensor device and reduce the manufacturing cost.
[0006] In view of this, how to reduce the number of photosensors used in the photosensor device, further miniaturize the photosensor device, and reduce the manufacturing cost is an urgent problem to be solved in the industry. Summary of the Invention
[0007] An object of the present invention is to use only a single photosensor in a photosensor device, further miniaturize the photosensor device and reduce the manufacturing cost. The present invention introduces an optical coating technology to design a gradient filter that can simultaneously filter three wavelengths or four wavelengths to define the receiving wavelength of the photosensor, and the received intensity can be adjusted down according to design requirements. For example, the proportion of light received by green light is the highest, followed by red light, and near-infrared light is weaker. Therefore, by adding a multi-channel filter, the present invention can not only exclude noise light other than the target wavelength to be measured, but also design to make a single photosensor have the same response value for different target wavelengths.
[0008] To achieve the above object, the present invention discloses a photosensor device, comprising: a carrier substrate; a plurality of light sources disposed on the carrier substrate; a photodiode sensor disposed on the carrier substrate and spaced apart from the light sources by a distance; and a multi-channel filter formed on an upper surface of the photodiode sensor, the multi-channel filter having a plurality of channels corresponding to light of a plurality of wavelengths of the light sources.
[0009] In one embodiment, the wavelengths include a first wavelength, a second wavelength, and a third wavelength, and the first wavelength, the second wavelength, and the third wavelength are different from each other and are between 300 and 1000 nm.
[0010] In one embodiment, the channels include a first channel corresponding to the first wavelength, a second channel corresponding to the second wavelength, and a third channel corresponding to the third wavelength, the light transmittance of the first channel, the second channel, and the third channel is between 25% and 98%, and the full width at half maximum of the first channel, the second channel, and the third channel is between 30 and 80 nm.
[0011] In one embodiment, the third wavelength is greater than the second wavelength and the second wavelength is greater than the first wavelength, and the light transmittance of the third channel is at least 5% less than the light transmittance of the second channel and the light transmittance of the second channel is at least 5% less than the light transmittance of the first channel.
[0012] In one embodiment, the first wavelength is 525 nm, the second wavelength is 660 nm, and the third wavelength is 940 nm.
[0013] In one embodiment, the wavelengths include a first wavelength, a second wavelength, a third wavelength, and a fourth wavelength, and the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength are different from each other and are between 300 and 1000 nm.
[0014] In one embodiment, the channel includes a first channel corresponding to the first wavelength, a second channel corresponding to the second wavelength, a third channel corresponding to the third wavelength, and a fourth channel corresponding to the fourth wavelength. The light transmittance of the first channel, the second channel, the third channel, and the fourth channel is between 25% and 98%, and the full width at half maximum (FWHM) of the first channel, the second channel, the third channel, and the fourth channel is between 30 and 80 nm.
[0015] In one embodiment, the fourth wavelength is greater than the third wavelength, the third wavelength is greater than the second wavelength, and the second wavelength is greater than the first wavelength. The light transmittance of the fourth channel is at least 5% less than that of the third channel, the light transmittance of the third channel is at least 5% less than that of the second channel, and the light transmittance of the second channel is at least 5% less than that of the first channel.
[0016] In one embodiment, the first wavelength is 525 nm, the second wavelength is 660 nm, the third wavelength is 850 nm, and the fourth wavelength is 940 nm.
[0017] In one embodiment, the multi-channel filter is formed by alternately stacking a first dielectric material layer and a second dielectric material layer to form a multi-layer structure. The first dielectric material layer is composed of one of tantalum pentoxide (Ta2O5) and titanium dioxide (TiO2), and the second dielectric material layer is composed of one of silicon dioxide (SiO2) and aluminum oxide (Al2O3).
[0018] In one embodiment, the multi-layer structure further includes an aluminum layer between two of the first dielectric material layers.
[0019] In one embodiment, the light source is a plurality of light emitting diodes (LEDs).
[0020] In one embodiment, the light sensor device is used for a wearable device.
[0021] In one embodiment, the light sensor device is used for a handheld device.
[0022] After referring to the accompanying drawings and the following described embodiments, those with ordinary technical knowledge in the technical field can understand other objectives of the present invention, as well as the technical means and embodiments of the present invention. Description of the Drawings
[0023] Figure 1A A top view schematic diagram of a light sensor device for an embodiment;
[0024] Figure 1B For Figure 1ASide view schematic diagram of a light sensor device;
[0025] Figure 2A Top view schematic diagram of a light sensor device of another embodiment;
[0026] Figure 2B is Figure 2A Side view schematic diagram of a light sensor device;
[0027] Figures 3A - 3E Illustrates the fabrication of a photodiode sensor and a multi-channel filter in one embodiment;
[0028] Figure 4 Shows the transmittance and full width at half maximum of the first channel, second channel, third channel, and fourth channel of the multi-channel filter; and
[0029] Figure 5 Shows, in one embodiment, the relative response value of the photodiode sensor to light of each wavelength before adding the multi-channel filter, and the response values of the photodiode sensor to the first wavelength, second wavelength, third wavelength, and fourth wavelength after adding the multi-channel filter.
[0030] Description of reference numerals
[0031] 100: Light sensor device
[0032] 200: Light sensor device
[0033] 11: Carrier substrate
[0034] 13a, 13b, 13c, 13d: Light sources
[0035] 15: Photodiode sensor
[0036] 17: Multi-channel filter
[0037] 27: Multi-channel filter
[0038] 151: Photodiode chip
[0039] 153: Upper electrode
[0040] 155: Lower electrode
[0041] 51: Curve
[0042] 52, 53, 54, 55: Columnar lines. Detailed implementation manners
[0043] The following will explain the content of the present invention through embodiments. The embodiments of the present invention are not intended to limit the present invention to be implemented in any specific environment, application, or special manner as described in the embodiments. Therefore, the description of the embodiments is only for the purpose of explaining the present invention and not for limiting the present invention. It should be noted that in the following embodiments and drawings, elements not directly related to the present invention have been omitted and not shown, and the dimensional relationships between the elements in the drawings are only for easy understanding and not for limiting the actual ratio.
[0044] An embodiment of the present invention is as Figure 1A and Figure 1B shown. Figure 1A It is a top view schematic diagram of a light sensor device 100. Figure 1B It is a side view schematic diagram of the light sensor device 100.
[0045] The light sensor device 100 includes a carrier substrate 11, a plurality of light sources 13a, 13b, 13c, a photodiode sensor 15, and a multi-channel filter 17.
[0046] In this embodiment, it is exemplified that the light sensor device 100 has three light sources 13a, 13b, 13c. However, in other examples, the light sensor device may have two light sources or more than three light sources. The light sources 13a, 13b, 13c are respectively disposed on the carrier substrate 11. The light sources 13a, 13b, 13c are a plurality of light emitting diodes (LEDs) that generate light of different target wavelengths. For example, the wavelengths (i.e., the first wavelength, the second wavelength, and the third wavelength) generated by the light sources 13a, 13b, 13c are between 300 and 1000 nm. For example, the wavelength of the light generated by the light source 13a (i.e., the first wavelength) is 525 nm, the wavelength of the light generated by the light source 13b (i.e., the second wavelength) is 660 nm, and the wavelength of the light generated by the light source 13c (i.e., the third wavelength) is 850 nm.
[0047] The photodiode sensor 15 is also disposed on the carrier substrate 11 and is spaced apart from the light sources 13a, 13b, 13c by a distance. The photodiode sensor 15 can be an indium gallium arsenide (InGaAs) photodiode sensor, but is not limited thereto. The wavelength range of the photodiode sensor 15 for photosensing can be 300 to 1100 nm, but is not limited thereto and can be changed depending on different applications.
[0048] A multi-channel filter 17 is formed on an upper surface of a photodiode sensor 15. The multi-channel filter 17 has a plurality of channels for light corresponding to the wavelengths of the light sources 13a, 13b, 13c (i.e., the first wavelength, the second wavelength, and the third wavelength). For example, the channels include a first channel corresponding to the first wavelength (e.g., 525 nm), a second channel corresponding to the second wavelength (e.g., 660 nm), and a third channel corresponding to the third wavelength (e.g., 850 nm).
[0049] Furthermore, the multi-channel filter 17 can be formed by alternately stacking a first dielectric material layer and a second dielectric material layer to form a multi-layer structure. For example, the first dielectric material layer can use a material with a higher refractive index, such as being composed of one of tantalum pentoxide (Ta2O5) and titanium dioxide (TiO2), and the second dielectric material layer can use a material with a lower refractive index, such as being composed of one of silicon dioxide (SiO2) and aluminum oxide (Al2O3). The refractive indices of the first dielectric material layer and the second dielectric material layer are between 1.4 and 3. For example, the refractive index of Ta2O5 is 2.1, the refractive index of TiO2 is 2.4, the refractive index of SiO2 is 1.48, and the refractive index of Al2O3 is 1.64. The multi-layer structure can include 40 to 70 layers, and its total thickness is between 3 and 10 μm, but the number of layers and the total thickness can be changed depending on different applications.
[0050] In addition, in one embodiment, the multi-layer structure can further include an aluminum layer between two first dielectric material layers. Since aluminum is a material with a very low refractive index, its refractive index is 1.2. Therefore, in the implementation of the present invention, by adding an aluminum layer to the multi-layer structure, the number of layers and the thickness of the required multi-layer structure can be reduced.
[0051] It should be noted that in Figure 1A and Figure 1B , the positions of the light sources 13a, 13b, 13c and the photodiode sensor 15 of the optical sensor device 100 on the carrier substrate 11 are only shown as schematic diagrams for illustration. Those of ordinary skill in the art can understand that with different actual applications, the positions of the light sources 13a, 13b, 13c and the photodiode sensor 15 will change. Therefore Figure 1A and Figure 1B the shown position settings are not used to limit the present invention. Furthermore, for simplicity of illustration, other components of the optical sensor device 100 such as a glass carrier plate, encapsulation, etc. are not shown in the drawings and will not be elaborated here.
[0052] Another embodiment of the present invention is as shown in Figure 2A and Figure 2B . Figure 2A It is a top view schematic diagram of an optical sensor device 200.Figure 2B It is a side view schematic diagram of the optical sensor device 200. Different from the optical sensor device 100, in this embodiment, it is exemplified that the optical sensor device 200 has four light sources 13a, 13b, 13c, and 13d. The light sources 13a, 13b, 13c, and 13d are respectively arranged on the carrier substrate 11. The light sources 13a, 13b, 13c, and 13d are multiple light-emitting diodes (LEDs) that generate light of different target wavelengths. For example, the wavelengths (i.e., the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength) generated by the light sources 13a, 13b, 13c, and 13d are between 300 and 1000 nm. For example, the wavelength of the light generated by the light source 13a (i.e., the first wavelength) is 525 nm, the wavelength of the light generated by the light source 13b (i.e., the second wavelength) is 660 nm, the wavelength of the light generated by the light source 13c (i.e., the third wavelength) is 850 nm, and the wavelength of the light generated by the light source 13d (i.e., the fourth wavelength) is 940 nm.
[0053] In addition, in this embodiment, different from the multi-channel filter 17 of the first embodiment, the multi-channel filter 27 has multiple channels corresponding to the light of the wavelengths (i.e., the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength) of the light sources 13a, 13b, 13c, and 13d. For example, the channels include a first channel corresponding to the first wavelength (e.g., 525 nm), a second channel corresponding to the second wavelength (e.g., 660 nm), a third channel corresponding to the third wavelength (e.g., 850 nm), and a fourth channel corresponding to the fourth wavelength (e.g., 940 nm).
[0054] It should be noted that in Figure 2A and Figure 2B , the position settings of the light sources 13a, 13b, 13c, and 13d and the photodiode sensor 15 of the optical sensor device 200 on the carrier substrate 11 are only exemplified as schematic diagrams. Those with ordinary technical knowledge in the technical field can understand that with different actual applications, the position settings of the light sources 13a, 13b, 13c, and 13d and the photodiode sensor 15 will change, so Figure 2A and Figure 2B The position settings shown are not used to limit the present invention. Similarly, for simplicity of description, other elements of the optical sensor device 200 such as the glass carrier plate, the encapsulation layer, etc. are not shown in the drawings and will not be elaborated here.
[0055] An embodiment of the present invention is as Figures 3A - 3E shown, which shows the fabrication of the photodiode sensor 15 and the multi-channel filter 17 (or multi-channel filter 27). For simplicity of description, Figures 3A - 3EOnly the multi-channel filter 17 is taken as an example for illustration. First, a photodiode chip 151 is provided, and a plurality of upper electrodes 153 are formed on the photodiode chip 151, as shown in Figure 3A (due to the limitation of the drawing layout, only 2 upper electrodes 153 are shown for illustration). Then, a lower electrode 155 is formed under the photodiode chip 151, as shown in Figure 3B , and a multi-channel filter 17 is plated on the photodiode chip 151 and the upper electrodes 153, as shown in Figure 3C .
[0056] Subsequently, the multi-channel filter 17 on the upper electrode 153 is removed (for example, using a yellow light lithography process), as shown in Figure 3D . Finally, dicing is performed to form a plurality of photodiode sensors 15 with a multi-channel filter 17 plated on the upper side.
[0057] It should be noted that Figures 3A - 3E is only an exemplary embodiment for illustrating a manufacturing method of the photodiode sensor 15 and the multi-channel filter 17. In other words, in practice, there may be other alternative schemes for the sequence of the manufacturing method and the processes used. Therefore, the manufacturing method of the photodiode sensor 15 and the multi-channel filter 17 of the present invention is not limited to the steps shown in Figures 3A - 3E .
[0058] For an embodiment of the present invention, please refer to Figure 4 and Figure 5 . As shown in Figure 4 , the light transmittance of the first channel (corresponding to the first wavelength), the second channel (corresponding to the second wavelength), and the third channel (corresponding to the third wavelength) of the multi-channel filter 17 is between 25% and 98%, and the full width at half maximum of the first channel, the second channel, and the third channel is between 30 and 80 nm.
[0059] In addition, as described above, the third wavelength (for example: 850 nm) is greater than the second wavelength (for example: 660 nm) and the second wavelength is greater than the first wavelength (for example: 525 nm). In the present invention, in order to make the photodiode sensor 15 have the same response value for different target wavelengths, the light transmittance of the third channel is at least 5% less than the light transmittance of the second channel and the light transmittance of the second channel is at least 5% less than the light transmittance of the first channel. For example, as shown in Figure 4 , the light transmittance of the third channel is 30%, the light transmittance of the second channel is 50%, and the light transmittance of the first channel is 95%.
[0060] Similarly, as shown in Figure 4As shown, the light transmittance of the first channel (corresponding to the first wavelength), the second channel (corresponding to the second wavelength), the third channel (corresponding to the third wavelength), and the fourth channel (corresponding to the fourth wavelength) of the multi-channel filter 27 ranges from 25% to 98%, and the full width at half maximum of the first channel, the second channel, the third channel, and the fourth channel ranges from 30 to 80 nm.
[0061] Similarly, as previously described, the fourth wavelength (e.g., 940 nm) is greater than the third wavelength (e.g., 850 nm), the third wavelength is greater than the second wavelength (e.g., 660 nm), and the second wavelength is greater than the first wavelength (e.g., 525 nm). In the present invention, in order to make the photodiode sensor 15 have the same response value for different target wavelengths, the light transmittance of the fourth channel is at least 5% less than that of the third channel, the light transmittance of the third channel is at least 5% less than that of the second channel, and the light transmittance of the second channel is at least 5% less than that of the first channel. For example, as Figure 4 shown, the light transmittance of the fourth channel is 25%, the light transmittance of the third channel is 30%, the light transmittance of the second channel is 50%, and the light transmittance of the first channel is 95%.
[0062] Figure 5 shows the relative response values of the photodiode sensor 15 to the light of each wavelength before adding the multi-channel filter 27 (such as the curve 51 shown in Figure 5 ), and after adding the multi-channel filter 27, the relative response values of the photodiode sensor 15 to the light of the first wavelength (e.g., 525 nm), the second wavelength (e.g., 660 nm), the third wavelength (e.g., 850 nm), and the fourth wavelength (e.g., 940 nm) (such as the bar lines 52, 53, 54, and 55 shown in Figure 5 ). It can be seen from Figure 5 that after adding the multi-channel filter 27 to the photodiode sensor 15 in the present invention, the photodiode sensor 15 can have the same response value for the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength. Therefore, in the present invention, by adding the multi-channel filter 17 or the multi-channel filter 27, the noise light other than the target wavelength to be measured can be effectively excluded, and the photodiode sensor 15 can have the same response value for different target wavelengths.
[0063] In practical applications, the optical sensor devices 100 and 200 of the present invention can be used in a wearable device (e.g., a smart watch, a smart bracelet, or any wearable device suitable for wearing on the human body). In addition, in practical applications, the optical sensor devices 100 and 200 of the present invention can also be used in a handheld device (e.g., a camera, a camera module of a mobile phone, or any handheld device having a camera module).
[0064] In summary, the photosensor device of the present invention uses only a single photodiode sensor, so the photosensor device can be effectively further miniaturized and the manufacturing cost can be reduced. Furthermore, the present invention introduces an optical coating technology to design a multi-channel filter that can simultaneously filter three wavelengths or four wavelengths to define the receiving wavelength of the photosensor, and the received intensity can be adjusted down according to the design requirements. Therefore, by adding the multi-channel filter, the present invention can not only exclude the noise light other than the target wavelength to be measured, but also enable the single photodiode sensor to have the same response value for different target wavelengths through design.
[0065] The above embodiments are only used to exemplify the implementation modes of the present invention and to explain the technical features of the present invention, rather than to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily completed by those skilled in the art belong to the scope claimed by the present invention, and the scope of the right protection of the present invention shall be subject to the claims.
Claims
1. A light sensor device, comprising: A carrier substrate; A plurality of light sources disposed on the carrier substrate; A photodiode sensor disposed on the carrier substrate and spaced apart from the light sources by a distance; and A multi-channel filter formed on an upper surface of the photodiode sensor, the multi-channel filter having a plurality of channels corresponding to light of a plurality of wavelengths of the light sources.
2. The optical sensor device according to claim 1, wherein, The wavelengths include a first wavelength, a second wavelength, and a third wavelength, and the first wavelength, the second wavelength, and the third wavelength are different from each other and are between 300 and 1000 nm.
3. The optical sensor device according to claim 2, wherein, The channels include a first channel corresponding to the first wavelength, a second channel corresponding to the second wavelength, and a third channel corresponding to the third wavelength. The light transmittance of the first channel, the second channel, and the third channel is between 25% and 98%, and the full width at half maximum of the first channel, the second channel, and the third channel is between 30 and 80 nm.
4. The photosensor device according to claim 3, wherein, The third wavelength is greater than the second wavelength and the second wavelength is greater than the first wavelength, and the light transmittance of the third channel is at least 5% less than the light transmittance of the second channel and the light transmittance of the second channel is at least 5% less than the light transmittance of the first channel.
5. The optical sensor device according to claim 3, wherein, The first wavelength is 525 nm, the second wavelength is 660 nm, and the third wavelength is 850 nm.
6. The optical sensor device according to claim 1, wherein, The wavelengths include a first wavelength, a second wavelength, a third wavelength, and a fourth wavelength, and the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength are different from each other and are between 300 and 1000 nm.
7. The photosensor device according to claim 6, wherein, The channels include a first channel corresponding to the first wavelength, a second channel corresponding to the second wavelength, a third channel corresponding to the third wavelength, and a fourth channel corresponding to the fourth wavelength. The light transmittance of the first channel, the second channel, the third channel, and the fourth channel is between 25% and 98%, and the full width at half maximum of the first channel, the second channel, the third channel, and the fourth channel is between 30 and 80 nm.
8. The photosensor device according to claim 7, wherein, The fourth wavelength is greater than the third wavelength, the third wavelength is greater than the second wavelength, and the second wavelength is greater than the first wavelength, and the light transmittance of the fourth channel is at least 5% less than the light transmittance of the third channel, the light transmittance of the third channel is at least 5% less than the light transmittance of the second channel, and the light transmittance of the second channel is at least 5% less than the light transmittance of the first channel.
9. The photosensor device according to claim 6, wherein, The first wavelength is 525 nm, the second wavelength is 660 nm, the third wavelength is 850 nm, and the fourth wavelength is 940 nm.
10. The photosensor device according to claim 1, wherein, The multi-channel filter is formed by alternately stacking a first dielectric material layer and a second dielectric material layer to form a multi-layer structure. The first dielectric material layer is composed of one of tantalum pentoxide and titanium dioxide, and the second dielectric material layer is composed of one of silicon dioxide and aluminum oxide.
11. The optical sensor device according to claim 10, wherein, The multi-layer structure further includes an aluminum layer between two of the first dielectric material layers.
12. The optical sensor device according to claim 1, wherein, The light sources are a plurality of light emitting diodes.
13. The optical sensor device according to claim 1, wherein, The light sensor device is used for a wearable device.
14. The photosensor device according to claim 1, wherein, The light sensor device is used for a handheld device.