Light sensor and electronic equipment
By broadening the coverage range of the metal layer in the photosensitive sensor and adding a filter layer, the problem of poor light shading effect of Dark PD in large-area PD is solved, and high-precision dark light detection is achieved.
Patent Information
- Application Number
- CN202422272405.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-09-14
AI Technical Summary
In light sensing applications, as the PD area becomes larger, the light-shielding effect of Dark PD becomes worse, resulting in the Dark PD's temperature drift cancel solution being unable to be used effectively, affecting the accuracy of dark light detection.
In the photosensitive sensor, by broadening the coverage range of the metal layer and adding an infrared cut-off filter layer and a visible filter layer, a multi-layer structure is formed to reduce light leakage, including a combination design of the metal layer, the filter layer and the glass layer to ensure that the light transmittance is less than 0.2%.
It effectively reduces the transmittance of visible and infrared light, improves the dark light detection accuracy of the light sensor, and enhances the detection effect of the light sensor.
Smart Images
Figure CN223297969U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of light sensors, and more specifically, to a light sensor and an electronic device. Background Art
[0002] In light-sensing applications, the dark current of a photodiode (PD) increases exponentially with increasing temperature. In low-light scenarios, the temperature drift of the dark current significantly impacts the sensitivity error, resulting in unexpected errors. In small-area PD or pixel applications, a hardware cancel is often used, subtracting the dark PD value in real time to improve low-light detection accuracy.
[0003] As the area of PD increases, it becomes difficult for Dark PD to achieve good light shielding. The degree of light leakage of Dark PD cannot be distinguished from the sensitivity to dark light, making the temperature drift cancel solution of Dark PD unusable. Utility Model Content
[0004] In response to the deficiencies in the prior art, the present application innovatively provides a light sensor and an electronic device that can solve at least some of the above technical problems.
[0005] To achieve the above technical objectives, the first aspect of the present application discloses a light sensor, comprising a dark light channel and a plurality of light sensitive channels, wherein a metal layer and a filter layer are provided on the dark light channel, wherein:
[0006] The metal layer covers the effective area of the dark light channel, and the coverage of the metal layer is larger than the area of the effective area.
[0007] The filter layer is arranged above the metal layer.
[0008] Furthermore, a distance between an edge of the metal layer and an edge of the active area is H, and H is greater than or equal to 33 μm.
[0009] Furthermore, the filter layer includes an infrared cutoff filter layer and a visible light filter layer.
[0010] Furthermore, the infrared cutoff filter layer is used to filter light with a wavelength of 755 nm or more, and / or,
[0011] The visible light filter layer is used to filter light with a wavelength of 400nm-750nm.
[0012] Furthermore, the infrared cutoff filter layer is composed of a coating, infrared glue or infrared film.
[0013] Furthermore, the light sensor further includes a glass layer, and the glass layer is arranged above the metal layer.
[0014] Furthermore, the filter layer is provided between the glass layer and the metal layer.
[0015] The infrared cutoff filter layer is formed below the glass layer, and the visible light filter layer is formed above the metal layer. Alternatively, the visible light filter layer is formed below the glass layer, and the infrared cutoff filter layer is formed above the metal layer.
[0016] Furthermore, the infrared cutoff filter layer and the visible light filter layer are bonded together by adhesive.
[0017] Furthermore, the filter layer is arranged above the metal layer and the glass layer.
[0018] The infrared cutoff filter layer and the visible light filter layer are respectively formed on the glass layer.
[0019] Furthermore, the infrared cutoff filter layer is formed on the glass layer, and the visible light filter layer is formed on the metal layer, or,
[0020] The visible light filter layer is formed on the glass layer, and the infrared cutoff filter layer is formed on the metal layer.
[0021] Furthermore, the plurality of light-sensing channels and the dark-light channels are distributed in a rectangular array.
[0022] Furthermore, a filter of the photosensitive channel adjacent to the dark light channel extends to the area where the dark light channel is located to form the visible light filter layer.
[0023] Furthermore, the visible light filter layer includes: a blue light filter layer, and / or a green light filter layer, and / or a red light filter layer.
[0024] Furthermore, the filter layer is a black filter layer.
[0025] Furthermore, the light sensor further includes a transparent conductive layer, and the transparent conductive layer is formed above or below the filter layer or the glass layer.
[0026] In a second aspect of the present application, an electronic device is disclosed, including a display screen, wherein the above-mentioned light sensor is provided on the lower side of the display screen.
[0027] The beneficial effects of this application are:
[0028] This application increases the coverage by widening the metal layer and adding a filter layer, so as to effectively attenuate light, achieve a full-band light shading effect, and improve the dark light detection accuracy of the light sensor. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 A schematic diagram showing the distribution of channels of a light sensor in related art is shown;
[0030] Figure 2 A cross-sectional schematic diagram of a dark light channel in the related art is shown;
[0031] Figure 3 A schematic diagram showing the distribution of channels of a light sensor according to an embodiment of the present application is shown;
[0032] Figure 4 A schematic diagram showing the relationship between the metal layer and the active area on the dark light channel according to an embodiment of the present application;
[0033] Figure 5 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown;
[0034] Figure 6 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown;
[0035] Figure 7 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown;
[0036] Figure 8 A schematic diagram showing the distribution of channels of a light sensor according to an embodiment of the present application is shown;
[0037] Figure 9 A schematic diagram showing the filtered spectrum of a light sensor according to an embodiment of the present application is shown;
[0038] Figure 10 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown;
[0039] Figure 11 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown;
[0040] Figure 12 A cross-sectional schematic diagram of a dark light channel according to an embodiment of the present application is shown.
[0041] In the figure,
[0042] 1. Dark light channel; 11. Effective area; 2. Photosensitive channel; 3. Metal layer; 4. Filter layer; 41. Infrared cutoff filter layer; 42. Visible light filter layer; 5. Glass layer; 6. Adhesive layer; 7. Transparent conductive layer. DETAILED DESCRIPTION
[0043] The ultrasonic fingerprint recognition structure and electronic device provided in this application are explained and illustrated in detail below in conjunction with the drawings in the specification.
[0044] like Figure 1 and Figure 2 As shown in the figure, in common light sensors, light can enter the interior of the Dark PD through the metal layer boundary. Conventional designs will produce more light leakage, thus affecting the light sensing accuracy.
[0045] According to the first aspect of the present application, a light sensor is provided, such as Figure 3 、 Figure 4 、 Figure 5 As shown, it includes a dark light channel 1 and multiple photosensitive channels 2, and the multiple photosensitive channels 2 include a red light channel R, a blue light channel B, a green light channel G, a visible light channel C, and a channel W without filtering processing. Among them, the red light channel R can only pass red light, the blue light channel B can only pass blue light, the green light channel G can only pass green light, the visible light channel C can only pass visible light, and the channel W without filtering processing is not filtered. Each photosensitive channel 2 may include one or more, and the multiple photosensitive channels 2 and the dark light channel 1 together form a rectangular or square array distribution.
[0046] In some embodiments, a metal layer 3 and a filter layer 4 are provided on the dark light channel 1 to filter visible light and infrared light to a lower level, for example, to reduce the transmittance of visible light and infrared light to below 0.2%.
[0047] The metal layer 3 covers the active area (AA) 11 of the dark light channel 1, that is, the active area 11 is entirely located within the area covered by the metal layer 3. Figure 4 As shown, the distance between the edge of the metal layer 3 and the edge of the effective area 11 is H, that is, the coverage of the metal layer 3 is larger than the effective area 11, and the effective area 11 is covered below the metal layer 3. Optionally, the effective area 11 and the metal layer 3 are both rectangular, and the distance between any edge of the effective area 11 and the edge of the adjacent metal layer 3 is H, which is greater than or equal to 33μm. The larger the value of H, the less visible light attenuation can be achieved. When H is 33μm, light below 900nm can be absorbed. Based on cost and overall size constraints, the value of H is preferably 45μm.
[0048] Filter layer 4 is disposed above metal layer 3, and the area of filter layer 4 is no less than that of metal layer 3. In some embodiments, filter layer 4 includes an infrared cutoff filter layer (IR-cut filter, IRC) 41 and a visible light filter layer 42, which can isolate at least some visible light and infrared light to a lower level. In some embodiments, the transmittance of infrared light and visible light, i.e., light with a wavelength of 400 nm to 1100 nm, can be reduced to no more than 0.2%, with an average transmittance of no more than 0.1%.
[0049] In some embodiments, the infrared cutoff filter layer 41 filters light with a wavelength of 755 nm or more. Optionally, the infrared cutoff filter layer 41 is formed by a coating, infrared glue, or infrared film.
[0050] Optionally, visible light filter layer 42 is a blue light filter layer that can isolate visible light components other than blue light to a lower level. In other embodiments, filters such as red and green light that filter wavelengths within the range of 400nm-750nm all have a certain filtering effect. Different filters can be selected as visible light filter layer 42 as needed. Alternatively, multiple filters of different colors can be overlapped to enhance the filtering effect.
[0051] In some embodiments, the light sensor further includes a glass layer 5 , which is disposed above the metal layer 3 .
[0052] In some embodiments, as Figure 6 As shown, the filter layer 4 is disposed between the glass layer 5 and the metal layer 3. Optionally, an infrared cutoff filter layer 41 is formed below the glass layer 5, and a visible light filter layer 42 is formed above the metal layer 3. In other embodiments, the visible light filter layer 42 may be formed below the glass layer 5, and the infrared cutoff filter layer 41 may be formed above the metal layer 3. The infrared cutoff filter layer 41 and the visible light filter layer 42 are bonded to each other via an adhesive layer 6. Optionally, DAF (die attach film) adhesive may be used for the adhesive layer 6.
[0053] As an optional embodiment, the filter layer 4 is disposed above the metal layer 3 and the glass layer 5 , and the infrared cutoff filter layer 41 and the visible light filter layer 42 are respectively formed above the glass layer 5 .
[0054] As another optional embodiment, the infrared cutoff filter layer 41 is formed on the glass layer 5, and the visible light filter layer 42 is formed on the metal layer 3, or,
[0055] The visible light filter layer 42 is formed on the glass layer 5 , and the infrared cut filter layer 41 is formed on the metal layer 3 .
[0056] In some embodiments, as Figure 8 As shown, the filter of a photosensitive channel 2 adjacent to the dark light channel 1 extends to the area where the dark light channel 2 is located, forming a visible light filter layer 42. For example, if the dark light channel 1 is adjacent to the blue light channel, the filter of the blue light channel is extended to cover the metal layer 3 of the dark light channel 1. It is easy to imagine that in other embodiments, such as if the red light channel or the green light channel is adjacent to the dark light channel 2, the filter of the red light channel or the green light channel can also be extended to form the visible light filter layer 42.
[0057] In some embodiments, as Figure 7 As shown, the filter layer 4 can also be a black filter layer, which can filter visible light and infrared light at the same time. For example, a black filter can be formed by using black materials that can be used for filtering, such as vinyl, foam, graphene, etc.
[0058] In the embodiment of the present application, by widening the metal layer 3 and adding the filter layer 4, the transmittance of visible light and infrared light, that is, light with a wavelength of 400nm-1100nm, can be effectively reduced to no more than 0.2%. Figure 9 As shown, curve I represents the maximum transmittance of the infrared cutoff filter layer 41 for light of different wavelengths, curve II represents the maximum transmittance of the blue light filter layer for light of different wavelengths, curve III represents the maximum transmittance of light of different wavelengths after the metal layer 3 is increased, and dotted line IV represents the maximum transmittance of light of different wavelengths after the three are superimposed (widening the metal layer 3 and adding the filter layer 4).
[0059] In some embodiments, the light sensor is encapsulated with black EMC (Epoxy Molding Compound Encapsulation) to reduce light leakage from the package. The light transmittance of dark light channel 1 is decomposed as follows:
[0060]
[0061] Among them, the stop band (ALS D ) is the spectral wavelength range after filtering; Crosstalk is the side leakage crosstalk, and passband (ALS RGBCW ) is the wavelength range of the filtered light wave. The above formula takes the setting of blue light filter as an example. is the transmittance of the blue light filter, is the transmittance of the infrared cutoff filter, is the transmittance of the metal layer, is the transmittance of side light leakage, where Blue RGBC , IRC RGBC , PD RGBCW The value range of is 400nm-1100nm, and the total transmittance is calculated to be ≤0.2%.
[0062] The light transmission consists of two parts: vertical incidence and crosstalk from the side of the package to the edge gap of the metal layer 3. The vertical incidence part is blocked by the metal layer 3 and the filter layer 4, and the side incidence part is blocked by the EMC.
[0063] In some embodiments, as Figure 10-12As shown, the light sensor further includes a transparent conductive layer 7. The transparent conductive layer 7 can be made of an organic or inorganic conductive coating or printed material, such as ITO (Indium Tin Oxide). The transparent conductive layer 7 can effectively shield external electrical interference without affecting the optical performance of the light sensor. Optionally, the transparent conductive layer 7 can be arranged above or below the filter layer 4 or the glass layer 5, for example, Figure 10 As shown, the transparent conductive layer 7 can be provided between the infrared cut-off filter layer 41 and the visible light filter layer 42, or as shown in FIG. Figure 11 As shown, the transparent conductive layer 7 is provided on the upper surface of the glass layer 5, or as Figure 12 As shown, when the filter layer 4 is a black filter layer, the transparent conductive layer 7 can be disposed on the upper surface of the filter layer 4 .
[0064] According to a second aspect of the present application, an electronic device is provided, including a display screen, wherein the above-mentioned light sensor is provided on the lower side of the display screen. Optionally, the electronic device includes a mobile phone, a tablet computer, a projector, and a vehicle-mounted device.
[0065] The preferred embodiments of the present application are described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.
Claims
1. A light sensor, characterized in that: It includes a dark light channel and multiple photosensitive channels, wherein a metal layer and a filter layer are provided on the dark light channel, wherein: The metal layer covers the effective area of the dark light channel, and the coverage of the metal layer is larger than the area of the effective area. The filter layer is arranged above the metal layer.
2. The light sensor according to claim 1, wherein: A distance H between an edge of the metal layer and an edge of the active area is greater than or equal to 33 μm.
3. The light sensor according to claim 1, wherein: The filter layer includes an infrared cutoff filter layer and a visible light filter layer.
4. The light sensor according to claim 3, characterized in that The infrared cut-off filter layer is used to filter light with a wavelength of 755 nm or more, and / or The visible light filter layer is used to filter light with a wavelength of 400nm-750nm.
5. The light sensor according to claim 4, characterized in that: The infrared cut-off filter layer is composed of a coating, infrared glue or infrared film.
6. The light sensor according to any one of claims 3 to 5, characterized in that: The light sensor further includes a glass layer, which is disposed above the metal layer.
7. The light sensor according to claim 6, characterized in that: The filter layer is arranged between the glass layer and the metal layer, The infrared cutoff filter layer is formed below the glass layer, and the visible light filter layer is formed above the metal layer. Alternatively, the visible light filter layer is formed below the glass layer, and the infrared cutoff filter layer is formed above the metal layer.
8. The light sensor according to claim 7, characterized in that: The infrared cutoff filter layer and the visible light filter layer are bonded together by adhesive.
9. The light sensor according to claim 6, characterized in that: The filter layer is arranged above the metal layer and the glass layer, The infrared cutoff filter layer and the visible light filter layer are respectively formed on the glass layer.
10. The light sensor according to claim 6, wherein: The infrared cutoff filter layer is formed on the glass layer, and the visible light filter layer is formed on the metal layer, or The visible light filter layer is formed on the glass layer, and the infrared cutoff filter layer is formed on the metal layer.
11. The light sensor according to claim 3, wherein: The plurality of light-sensing channels and the dark-light channels are distributed in a rectangular array.
12. The light sensor according to claim 11, wherein: The filter of one of the photosensitive channels adjacent to the dark light channel extends to the area where the dark light channel is located to form the visible light filter layer.
13. The light sensor according to claim 3, characterized in that: The visible light filter layer includes: a blue light filter layer, and / or a green light filter layer, and / or a red light filter layer.
14. The light sensor according to claim 1, wherein: The filter layer is a black filter layer.
15. The light sensor according to claim 6, characterized in that: The light sensor further includes a transparent conductive layer, which is formed above or below the filter layer or the glass layer.
16. An electronic device, characterized in that: It comprises a display screen, and a light sensor according to any one of claims 1 to 15 is arranged on the lower side of the display screen.