Photodiode, light sensing chip and electronic equipment

Abstract

The utility model discloses a photodiode, photosensitive chip and electronic equipment, photodiode includes substrate, photosensitive unit, shading layer and first filter stack, a plurality of photosensitive units are provided on the substrate, shading layer covers one of the photosensitive units, first filter stack covers the shading layer, the first filter stack covers the shading layer, the first filter stack covers the shading layer, the first filter stack covers the first filter stack, and the plurality of photosensitive units are arranged on the substrate. The first filter lamination layer comprises a first color filter film and an infrared cut-off filter film which are laminated. Or the photodiode comprises a substrate, a photosensitive unit and a second filtering lamination layer, the photosensitive unit is arranged on the substrate, the second filtering lamination layer covers the photosensitive unit, and the second filtering lamination layer comprises a second color filtering film and a second infrared filtering film which are laminated. The light sensing chip comprises the photodiode. The electronic equipment comprises the light sensing chip. According to the utility model, the optical sensitivity of the stacked structure of the first filtering lamination layer and the shading layer to the full-wave band 400-1000nm light is less than 1%, and the second filtering lamination layer can effectively inhibit visible light, thereby improving the performance of the photodiode.

Description

Technical Field

[0001] The utility model relates to the technical field of optoelectronic communication. More specifically, the utility model relates to a photodiode, a photosensing chip and an electronic device. Background Art

[0002] The photosensing chip includes an ambient light detection chip (Ambient Light Sensor, ALS) and a proximity sensing chip (Proximity Sensor, PS). Both types of chips extract, detect, and apply and convert optical signals of specific wavelengths. Their basic detection unit is a photodiode (Photo-Diode, PD). The PD is an optical device for long-wavelength detection and cannot detect optical signals of specific bands alone. It needs to be combined with an optical path design to achieve the detection of optical signals of specific bands. In practical applications, the optical performance of the photodiode needs to be improved. Summary of the Utility Model

[0003] Aiming at the deficiencies of the prior art, the utility model innovatively provides a photodiode, a photosensing chip and an electronic device. The structure of the first filter stack and the light-shielding layer stacked has an optical sensitivity to light in the full band of 400-1000nm of <1%. The Dark PD formed by the first filter stack, the light-shielding layer and the photosensing unit below it can effectively suppress and eliminate the dark current temperature drift of the remaining photosensing channels, enabling the photodiode to be applied in any ambient light scenario; the second filter stack can effectively suppress visible light, thereby improving the light sensing performance of the photodiode.

[0004] To achieve the above technical objectives, the first aspect of the utility model discloses a photodiode, which includes a substrate, a photosensing unit, a light-shielding layer and a first filter stack.

[0005] A plurality of the photosensing units are arranged on the substrate, the light-shielding layer covers one of the photosensing units, and the first filter stack covers the light-shielding layer.

[0006] The first filter stack includes a first color filter film and an infrared cut-off filter film stacked on top of each other.

[0007] Furthermore, the first filter stack further includes a first transparent substrate. The first transparent substrate is arranged above or below the stacked first color filter film and the infrared cut-off filter film, or is arranged between the first color filter film and the infrared cut-off filter film. One of the first color filter film and the infrared cut-off filter film is arranged above the first transparent substrate, and the other is arranged below the first transparent substrate.

[0008] Furthermore, the first transparent substrate is a glass plate or a transparent optical resin plate.

[0009] Further, the first filter stack is adhesively fixed to the light-shielding layer and / or the substrate.

[0010] Further, the first color filter film is one of a red light filter film, a green light filter film, or a blue light filter film.

[0011] Further, the light-shielding layer is a metal layer.

[0012] To achieve the above technical objectives, a second aspect of the present utility model discloses a photodiode, which includes a substrate, a photosensitive unit, and a second filter stack.

[0013] The photosensitive unit is disposed on the substrate, and the second filter stack covers the photosensitive unit.

[0014] The second filter stack includes a stacked second color filter film and a second infrared filter film.

[0015] Further, the second filter stack further includes a second transparent substrate, the second transparent substrate is disposed above or below the stacked second color filter film and the second infrared filter film, or is disposed between the second color filter film and the second infrared filter film, and one of the second color filter film and the second infrared filter film is disposed above the second transparent substrate and the other is disposed below the second transparent substrate.

[0016] Further, the second transparent substrate is a glass plate or a transparent optical resin plate.

[0017] Further, the second filter stack is adhesively fixed to the photosensitive unit and / or the substrate.

[0018] Further, the second color filter film is one of a red light filter film, a green light filter film, or a blue light filter film.

[0019] To achieve the above technical objectives, a third aspect of the present utility model discloses a photosensing chip, which includes the photodiode described in the first aspect or the second aspect.

[0020] To achieve the above technical objectives, a fourth aspect of the present utility model discloses an electronic device, which includes the photosensing chip described in the third aspect.

[0021] The beneficial effects of the present utility model are:

[0022] For the photodiode of the present utility model, the structure formed by the stacked first filter stack and light-shielding layer has an optical sensitivity to light in the full wavelength range of 400 - 1000 nm of < 1%. The Dark PD formed by the first filter stack, the light-shielding layer and the photosensitive unit below it can effectively suppress and eliminate the dark current temperature drift of the remaining photosensitive channels, enabling the photodiode to be applied in any ambient light scenario; the second filter stack can effectively suppress visible light, thereby improving the light sensing performance of the photodiode. Brief Description of the Drawings

[0023] Figure 1 is a top view of the photodiode of the ambient light detection chip in the prior art.

[0024] Figure 2 is a top view of the photodiode of the proximity light detection chip in the prior art.

[0025] Figure 3 is a top view of the photodiode of the first embodiment of the present utility model.

[0026] Figure 4 is a side view of the photodiode of the first embodiment of the present utility model.

[0027] Figure 5 is a side view of the photodiode of the second embodiment of the present utility model.

[0028] Figure 6 is a comparison chart of different Dark PD optical response curves.

[0029] Figure 7 is a top view of the photodiode of the third embodiment of the present utility model.

[0030] Figure 8 is a side view of the photodiode of the third embodiment of the present utility model.

[0031] Figure 9 is a side view of the photodiode of the fourth embodiment of the present utility model.

[0032] In the figure,

[0033] 1. Substrate; 2. Photosensitive unit; 3. Metal layer; 4. Light-shielding layer; 5. First filter stack; 51. First color filter film; 52. Infrared cut-off filter film; 53. First transparent substrate; 6. Adhesive; 7. First infrared filter film; 8. Second filter stack; 81. Second color filter film; 82. Second infrared filter film; 83. Second transparent substrate. Detailed Embodiments

[0034] The following will explain and illustrate in detail the photodiode, light sensing chip and electronic device provided by the present utility model with reference to the accompanying drawings of the specification.

[0035] The existing structure of the PD is as shown in Figure 1 and 2 shown, including a substrate 1 and one or more photosensitive units 2 on the substrate 1.

[0036] The ambient light detection chip includes signal detection of R / G / B / W / C / D channels, corresponding to signals of red / green / blue / white / visible / dark light channels respectively; among them, the R / G / B / W / C channels sense ambient light signals in the corresponding wavelength bands. The above photosensitive channels are composed of one or several photosensitive units 2 in the PD that detect light of the corresponding wavelength. For example, one or several photosensitive units 2 that detect red light form the red light channel. According to the electrical characteristics of the PD itself, the corresponding optical signal is converted into an electrical signal (photoelectric current signal). However, there is a dark current signal in the PD itself, and this dark current signal will change with temperature (temperature drift characteristic), and will be superimposed on the photoelectric current signal of the PD, affecting the physical signal mapping of the ambient light. In order to eliminate the influence of the dark current, as shown in Figure 1 shown, in the prior art, a metal layer 3 for light shielding is provided on one of the multiple photosensitive units 2 of the PD to form a Dark PD (dark light channel), making it insensitive to ambient light, but still having the dark current electrical characteristics of the PD itself. The dark current of the Dark PD is used as a reference to eliminate the dark current of the remaining photosensitive channels, so that the electrical signal generated by the ambient light detected by the other photosensitive channels is a pure photoelectric current signal (without dark current), but this function is only realized under dark light conditions.

[0037] In actual application, there are many ambient light scenarios. Although the light sensitivity of the metal layer 3 is very low, it is not close to 0, and its ability to isolate ambient light is limited, so that its current includes both dark current and photoelectric current. When the dark current temperature drift of the remaining photosensitive channels needs to be eliminated, the extracted dark current signal of the Dark PD is also doped with a photoelectric current signal, affecting the elimination effect, and ultimately resulting in the failure of the function of the Dark PD.

[0038] This embodiment specifically discloses a photodiode, as shown in Figures 3 - 5 shown, including a substrate 1, a photosensitive unit 2, a light shielding layer 4 and a first filter stack 5. A plurality of photosensitive units 2 are arranged on the substrate 1, and a spacing is maintained between adjacent photosensitive units 2. The light shielding layer 4 covers one of the photosensitive units 2, and the light shielding layer 4 is preferably a metal layer. As shown in Figure 3 and 4As shown, multiple photosensitive units 2 are tiled on the substrate 1, and the upper surface of the photosensitive unit 2 is flush with the upper surface of the substrate 1. The light-shielding layer 4 completely covers the photosensitive unit 2 below it, and the area of the light-shielding layer 4 is greater than or equal to the area of the photosensitive unit 2, that is, the edge of the light-shielding layer 4 can be flush with the edge of the photosensitive unit 2 below it, and the light-shielding layer 4 can also extend to the substrate 1 around the photosensitive unit 2, but the light-shielding layer 4 does not cover other photosensitive units 2. The remaining photosensitive units 2 form photosensitive channels. For example, one or several photosensitive units 2 for detecting red light form a red light channel, one or several photosensitive units 2 for detecting green light form a green light channel, and one or several photosensitive units 2 for detecting blue light form a blue light channel.

[0039] The first filter stack 5 covers the light-shielding layer 4. The first filter stack 5 includes a stacked first color filter film 51 (Color Filter, CF) and an infrared cut-off filter film 52 (IR Cut Filter, IRC). The first filter stack 5 completely covers the light-shielding layer 4, and the area of the first filter stack 5 is greater than or equal to the area of the light-shielding layer 4, that is, the edge of the first filter stack 5 can be flush with the edge of the light-shielding layer 4, and the first filter stack 5 can also extend to the substrate 1 around the light-shielding layer 4, but the first filter stack 5 does not cover other photosensitive units 2. The first color filter film 51 is used to filter visible light in a certain band within the range of 400 - 750 nm (i.e., within the visible light range). Except for the transmissible band, the response to the remaining bands of visible light is < 1%. Preferably, the first color filter film 51 is one of a red light filter film, a green light filter film, or a blue light filter film. The red light filter film is used to filter red light and only allows red light and infrared light to pass through; the green light filter film is used to filter green light and only allows green light and infrared light to pass through; the blue light filter film is used to filter blue light and only allows blue light and infrared light to pass through. The infrared cut-off filter film 52 is used to isolate infrared light above 755 nm to a lower level, and the response to the infrared light band with a wavelength > 755 nm is < 1%. Moreover, in the film system design of the infrared cut-off filter film 52, the suppression ability (blue film response) when large-angle infrared light is incident is considered. When large-angle light is incident, the suppression ability of the infrared cut-off filter film 52 will shift towards the blue light band direction, resulting in a decrease in the suppression ability of infrared light. Therefore, in the actual processing of the infrared cut-off filter film 52 in this application, the suppression ability in the direction of normal incident of ambient light and large-angle incident is considered, and the infrared light suppression ability is improved through film system design. Therefore, after the light passes through the first filter stack 5, almost only red light, green light, or blue light can pass through, and the light of the remaining bands is almost completely blocked, with a response < 1%. Coupled with the blocking effect of the light-shielding layer 4, the interception effect of light in the full band of 400 - 1000 nm can be achieved.

[0040] One of the first color filter film 51 and the infrared cut-off filter film 52 is disposed above the other. The first color filter film 51 can be disposed above the infrared cut-off filter film 52, or the infrared cut-off filter film 52 can be disposed above the first color filter film 51. This application does not specifically limit the stacking order of the first color filter film 51 and the infrared cut-off filter film 52, that is, the filtering order of light is not limited.

[0041] As Figure 4 shown, the first color filter film 51 is disposed on the infrared cut-off filter film 52. After the ambient light is filtered by the first color filter film 51, only visible light of one of the red, green, or blue bands and infrared light pass through, and irradiate the infrared cut-off filter film 52. The infrared cut-off filter film 52 intercepts the infrared light therein, and only visible light of one of the bands irradiates the light-shielding layer 4. The light-shielding layer 4 intercepts the visible light of this band, and finally almost no light enters the photosensitive unit 2 below the light-shielding layer 4, forming a dark light path, and only having the dark current electrical characteristics of the PD itself.

[0042] As Figure 5 shown, the infrared cut-off filter film 52 is disposed above the first color filter film 51. After the ambient light is filtered by the infrared cut-off filter film 52, the infrared light is intercepted, and only visible light irradiates the first color filter film 51. After being filtered by the first color filter film 51, only visible light of one of the red, green, or blue bands passes through, irradiates the light-shielding layer 4, and the light-shielding layer 4 intercepts the visible light of this band. Finally, almost no light enters the photosensitive unit 2 below the light-shielding layer 4, forming a dark light path, and only having the dark current electrical characteristics of the PD itself.

[0043] It can be seen that the first filter stack 5, the light-shielding layer 4, and the photosensitive unit 2 below it form a Dark PD. Taking the first color filter film 51 as a blue light filter film as an example, almost only blue light passes through after the light passes through the first filter stack 5, and then through the blocking effect of the light-shielding layer 4, the blue light is also intercepted. The optical sensitivity of the Dark PD to light in the full wavelength range of 400-1000 nm < 1%, and the sensitivity to ambient light approaches the effect of a dark room condition. The current of the Dark PD only includes the dark current, and the photocurrent is completely eliminated. Therefore, when the Dark PD is used as a reference channel for the dark current, it only provides a dark current signal to eliminate the dark current of the other photosensitive channels, so that the electrical signal generated by the ambient light detected by the other photosensitive channels is a pure photocurrent signal (without dark current).

[0044] As Figure 3 and 4As shown, the first filter stack 5 only includes a first color filter film 51 and an infrared cut-off filter film 52. The first filter stack 5 can be directly processed on the light-shielding layer 4. If the first color filter film 51 is disposed on the infrared cut-off filter film 52, during processing, first, the existing photodiode epitaxial design is carried out, the light-shielding layer 4 is formed on one of the photosensitive units 2, then the infrared cut-off filter film 52 is formed by coating on the light-shielding layer 4, and finally the first color filter film 51 is formed by spin coating on the infrared cut-off filter film 52. If the infrared cut-off filter film 52 is disposed on the first color filter film 51, during processing, first, the existing photodiode epitaxial design is carried out, the light-shielding layer 4 is formed on one of the photosensitive units 2, then the first color filter film 51 is formed by spin coating on the light-shielding layer 4, and then the infrared cut-off filter film 52 is formed by coating on the first color filter film 51. Through the above method, the existing photodiode, the light-shielding layer 4 and the first filter stack 5 can be integrated, and it is easy to operate during packaging.

[0045] In some embodiments, as Figure 5 shown, the first filter stack 5 further includes a first transparent substrate 53. The first transparent substrate 53 is disposed above or below the stacked first color filter film 51 and infrared cut-off filter film 52, or is disposed between the first color filter film 51 and the infrared cut-off filter film 52. One of the first color filter film 51 and the infrared cut-off filter film 52 is disposed above the first transparent substrate 53 and the other is disposed below the first transparent substrate 53. The first color filter film 51 and the infrared cut-off filter film 52 are disposed on the surface of the first transparent substrate 53. The first transparent substrate 53 serves as a carrier substrate for the first color filter film 51 and the infrared cut-off filter film 52, but does not affect the filtering effect. The first color filter film 51 and the infrared cut-off filter film 52 can be stacked on the upper surface of the first transparent substrate 53, can also be stacked on the lower surface of the first transparent substrate 53, or one of them can be disposed on the upper surface of the first transparent substrate 53 and the other can be disposed on the lower surface of the first transparent substrate 53. The first color filter film 51 still adopts the spin coating processing method, and the infrared cut-off filter film 52 is formed by coating. The area of the first transparent substrate 53 is greater than or equal to the areas of the first color filter film 51 and the infrared cut-off filter film 52.

[0046] Optionally, the first transparent substrate 53 is a glass plate or a transparent optical resin plate. The transparent optical resin plate can be a phenolic resin plate, a PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol ester) resin plate or a PMMA (polymethyl methacrylate) resin plate.

[0047] Optionally, the first filter stack 5 is adhesively fixed to the light-shielding layer 4 and / or the substrate 1. The adhesive 6 is glue, preferably DAF glue (Die Attach Film). When the areas of the first filter stack 5 and the light-shielding layer 4 are the same, the first filter stack 5 is adhesively bonded only to the light-shielding layer 4. When the area of the first filter stack 5 is larger than that of the light-shielding layer 4, the first filter stack 5 can be adhesively bonded only to the substrate 1 around the light-shielding layer 4 or to the light-shielding layer 4 and the substrate 1 around the light-shielding layer 4. Preferably, the entire lower surface of the first filter stack 5 is adhesively bonded to the light-shielding layer 4 below it and / or the substrate 1 around the light-shielding layer 4. When the first transparent substrate 53 is provided at the bottom layer of the first filter stack 5, the adhesive 6 is coated on the lower surface of the first transparent substrate 53; when the first transparent substrate 53 is provided at the top layer of the first filter stack 5 or between the first color filter film 51 and the infrared cut-off filter film 52, the adhesive 6 is coated on the lower surface of the bottommost first color filter film 51 or infrared cut-off filter film 52 and extends to the first transparent substrate 53 surrounding the first color filter film 51 and the infrared cut-off filter film 52.

[0048] Taking the example where the first color filter film 51 and the infrared cut-off filter film 52 are stacked on the upper surface of the first transparent substrate 53 to illustrate Figure 5 The manufacturing method of the photodiode of the illustrated embodiment is as follows: First, a light-shielding layer 4 is fabricated on one of the photosensitive units 2 of the existing photodiode. The first color filter film 51 and the infrared cut-off filter film 52 are fabricated on the first transparent substrate 53 in a stacked order. Then, the bottom of the first transparent substrate 53 is bonded to the upper surface of the light-shielding layer 4 and / or the substrate 1 around the light-shielding layer 4 through the adhesive 6, ensuring that the first color filter film 51 and the infrared cut-off filter film 52 completely cover the light-shielding layer 4 during bonding. Through the setting of the first transparent substrate 53, the first filter stack 5 has a certain hardness and flatness, and the first filter stack 5 can be fabricated separately first and then bonded to the light-shielding layer 4 and / or the substrate 1 around the light-shielding layer 4, with simple operation and low cost.

[0049] As Figure 6 shown, PD Only represents the existing PD structure, where no light-shielding layer 4 and filter film are provided on the photosensitive unit 2; Metal represents that a metal layer is provided on one of the photosensitive units 2, and the metal layer serves as the light-shielding layer 4; Metal+IRC represents that a metal layer is provided on one of the photosensitive units 2 as the light-shielding layer 4, and an infrared cut-off filter film 52 is provided on the light-shielding layer 4; Metal+Blue CF+IRC represents the Dark PD structure of the present application, where a metal layer is provided on one of the photosensitive units 2 as the light-shielding layer 4, and an infrared cut-off filter film 52 and a first color filter film 51 are provided on the light-shielding layer 4. The first color filter film 51 is a blue color filter (Blue Color Filter, Blue CF). FromFigure 6 It can be clearly seen that if there is only Metal on the PD, the Dark PD will still have an ambient light response of about 2.5%; if IRC is added on the basis of Metal, there will be a visible light response of about 2%; if IRC and Blue Color Filter are added on the basis of Metal, the Dark PD will have a response of about 0.4%, which already meets the requirement that the full-band light response of the application requirement for Dark PD is <1%.

[0050] In summary, the light response of the Dark PD of the photodiode of the present application in the full band of 400-1000 nm is suppressed to a low level and can be applied to any ambient light scenario.

[0051] The present application discloses a light-sensing chip, including the photodiode of the above embodiment. The light-sensing chip is an ambient light detection chip and can be applied to any ambient light scenario.

[0052] The characteristic of the proximity sensing chip is to detect only the infrared band light signal and is not sensitive to the visible light band. The desired photosensitive band of the proximity sensing chip is the band of the emission light source, generally the infrared light band, conventionally 850±10 nm or 940±10 nm. For light signals outside this photosensitive band, it is necessary to suppress non-sensitivity. The ideal application scheme of the proximity sensing chip is that the PD receives infrared light with a wavelength of 850±10 nm or 940±10 nm. When an object approaches the chip, the signal amount of the PD reaction will change. When this change exceeds the proximity sensing threshold, it is determined as proximity sensing. However, in actual applications, the proximity sensing chip is interfered by ambient light (including sunlight, indoor and outdoor lights, or screen light), especially screen light (in the 400-755 nm band). Different screen display modes will trigger the screen to dim in a pulse form. If the PD of the proximity sensing chip responds to the screen light, signals of approaching / leaving will frequently appear, resulting in misjudgment. Therefore, the suppression of the proximity sensing chip to the visible light band (400-755 nm) is crucial.

[0053] As Figure 2 shown, the solution adopted in the prior art is to add a first infrared filter film 7 (IR pass, IRP) on the surface of the photosensitive unit 2 of the PD to filter out the "screen interference light" in the visible light band, but the suppression effect is not good, so that in some scenarios, the PD of the proximity sensing chip will still sense the light under the screen, resulting in the PWM (Pulse Width Modulation) signal generated when the screen dims being misjudged as a proximity sensing signal by the PD detection.

[0054] The present application also discloses a photodiode, as Figures 7 - 9As shown, it includes a substrate 1, a photosensitive unit 2, and a second filter stack 8. The photosensitive unit 2 is disposed on the substrate 1, as Figure 8 and 9 shown, the photosensitive unit 2 is laid flat on the substrate 1, and the upper surface of the photosensitive unit 2 is flush with the upper surface of the substrate 1; the second filter stack 8 covers the photosensitive unit 2, and the second filter stack 8 completely covers the photosensitive unit 2 below it. The area of the second filter stack 8 is greater than or equal to the area of the photosensitive unit 2, that is, the edge of the second filter stack 8 can be flush with the edge of the photosensitive unit 2 below it, and the second filter stack 8 can also extend to the substrate 1 around the photosensitive unit 2. The second filter stack 8 includes a stacked second color filter film 81 (Color Filter, CF) and a second infrared filter film 82 (IR Pass, IRP). The second color filter film 81 is used to filter visible light in a certain band within the visible light range. Except for the transmissible band, the response of the visible light in the remaining cut-off bands is <1%. Preferably, the second color filter film 81 is one of a red light filter film, a green light filter film, or a blue light filter film. The red light filter film is used to filter red light and only allows red light and infrared light to pass through; the green light filter film is used to filter green light and only allows green light and infrared light to pass through; the blue light filter film is used to filter blue light and only allows blue light and infrared light to pass through. The second infrared filter film 82 is used to filter infrared light and only allows infrared light to pass through. The setting of the second color filter film 81 can further intercept visible light in a specific band in visible light and improve the visible light interception effect. After passing through the second filter stack 8, almost only infrared light passes through, and the light in other bands is intercepted, and the response to visible light is <1%.

[0055] One of the second color filter film 81 and the second infrared filter film 82 is disposed above the other. The second color filter film 81 can be disposed above the second infrared filter film 82, and the second infrared filter film 82 can also be disposed above the second color filter film 81. The present application does not specifically limit the stacking order of the second color filter film 81 and the second infrared filter film 82, that is, the filtering order of light is not limited.

[0056] As Figure 8 shown, the second color filter film 81 is disposed on the second infrared filter film 82. After the ambient light passes through the filtering of the second color filter film 81, only visible light in one band of red light, green light, or blue light and infrared light pass through, irradiating the second infrared filter film 82. The second infrared filter film 82 then intercepts the visible light therein and only allows infrared light to pass through, and finally almost no visible light enters the photosensitive unit 2.

[0057] As Figure 9As shown, the second infrared filter film 82 is disposed above the second color filter film 81. After the ambient light is filtered by the second infrared filter film 82, only infrared light can pass through, and visible light may be doped therein. After the second color filter film 81 intercepts the light of a specific wavelength band in the visible light doped in the infrared light, only infrared light and a negligible amount of visible light of a certain wavelength band can pass through, and finally almost no visible light enters the photosensitive unit 2. Taking the second color filter film 81 as a blue light filter film as an example, after being filtered by the second infrared filter film 82, most of the visible light is intercepted, and the remaining visible light enters the blue light filter film. There may be a small amount of blue light in the remaining visible light. Therefore, after being filtered by the blue light filter film, almost no visible light may pass through.

[0058] Thus, it can be seen that the second filter stack 8 can achieve an optical sensitivity of <1% for visible light of 400 - 750 nm.

[0059] As Figure 7 and 8 shown, the second filter stack 8 only includes the second color filter film 81 and the second infrared filter film 82, and the second filter stack 8 can be directly processed on the photosensitive unit 2. If the second color filter film 81 is disposed on the second infrared filter film 82, during processing, the second infrared filter film 82 is formed by coating on the photosensitive unit 2 or on the photosensitive unit 2 and the substrate 1, and then the second color filter film 81 is formed by spin coating on the second infrared filter film 82. If the second infrared filter film 82 is disposed on the second color filter film 81, during processing, the second color filter film 81 is formed by spin coating on the photosensitive unit 2 or on the photosensitive unit 2 and the substrate 1, and then the second infrared filter film 82 is formed by coating on the second color filter film 81. The above method integrates the existing photodiode and the second filter stack 8, which is easy to operate during packaging.

[0060] In some embodiments, as Figure 9As shown, the second filter stack 8 further includes a second transparent substrate 83, which is disposed above or below the stacked second color filter film 81 and second infrared filter film 82, or between the second color filter film 81 and the second infrared filter film 82. One of the second color filter film 81 and the second infrared filter film 82 is disposed above the second transparent substrate 83 and the other is disposed below the second transparent substrate 83. The second color filter film 81 and the second infrared filter film 82 are disposed on the surface of the second transparent substrate 83. The second transparent substrate 83 serves as the carrier substrate for the second color filter film 81 and the second infrared filter film 82, but does not affect the filtering effect. The second color filter film 81 and the second infrared filter film 82 can be stacked on the upper surface of the second transparent substrate 83, or can be stacked on the lower surface of the second transparent substrate 83, or one can be disposed on the upper surface of the second transparent substrate 83 and the other can be disposed on the lower surface of the second transparent substrate 83. The second color filter film 81 still adopts the spin coating processing method, and the second infrared filter film 82 is formed by coating. The area of the second transparent substrate 83 is greater than or equal to the areas of the second color filter film 81 and the second infrared filter film 82.

[0061] The second transparent substrate 83 is a glass plate or a transparent optical resin plate. The transparent optical resin plate can be a phenolic resin plate, a PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol ester resin plate) or a PMMA (polymethyl methacrylate resin plate).

[0062] The second filter stack 8 is adhesively fixed to the photosensitive unit 2 and / or the substrate 1. The adhesive 6 is glue, preferably DAF glue. When the area of the second filter stack 8 is the same as that of the photosensitive unit 2, the second filter stack 8 is adhesively fixed only to the photosensitive unit 2. When the area of the second filter stack 8 is larger than that of the photosensitive unit 2, the second filter stack 8 can be adhesively fixed only to the substrate 1 around the photosensitive unit 2 or to the photosensitive unit 2 and the substrate 1 around the photosensitive unit 2. Preferably, the entire lower surface of the second filter stack 8 is adhesively fixed to the photosensitive unit 2 and / or the substrate 1 around the photosensitive unit 2 below it. When the second transparent substrate 83 is disposed at the bottom layer of the second filter stack 8, the adhesive 6 is coated on the lower surface of the second transparent substrate 83; when the second transparent substrate 83 is disposed at the top layer of the second filter stack 8 or between the second color filter film 81 and the second infrared filter film 82, the adhesive 6 is coated on the lower surface of the lowermost second color filter film 81 or second infrared filter film 82 and extends to the upper surface of the second transparent substrate 83 surrounding the second color filter film 81 and the second infrared filter film 82.

[0063] Taking the case where the second color filter film 81 and the second infrared filter film 82 are stacked on the upper surface of the second transparent substrate 83 as an example for illustration Figure 9A method for manufacturing a photodiode of the illustrated embodiment. First, a second color filter film 81 and a second infrared filter film 82 are fabricated on a second transparent substrate 83 in a stacked order. Then, the bottom of the second transparent substrate 83 is adhered to the upper surface of the photosensitive unit 2 and / or the substrate 1 around the photosensitive unit 2 by an adhesive 6. When adhering, ensure that the second color filter film 81 and the second infrared filter film 82 completely cover the photosensitive unit 2. Through the provision of the second transparent substrate 83, the second filter stack 8 has a certain hardness and flatness. The second filter stack 8 can be fabricated separately first and then adhered to the photosensitive unit 2 and / or the substrate 1 around the photosensitive unit 2, with simple operation and low cost.

[0064] This application also discloses a light sensing chip, including the above-mentioned photodiode. The light sensing chip is a proximity sensing chip, and this application improves the detection accuracy of the proximity sensing chip.

[0065] This application also discloses an electronic device, including the light sensing chip described in the above embodiment. The electronic device is an electronic device using the light sensing chip, and it can be a laptop computer, a mobile phone, a tablet computer, a desktop computer, a gaming device, an in-vehicle electronic device, a wearable intelligent device, etc.

[0066] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0067] In the present utility model, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0068] In the description of this specification, the descriptions with reference to terms such as "this embodiment", "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any at least one embodiment or example. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0069] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0070] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements and simple improvements made to the substantial content of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A photodiode, characterized in that: It comprises a substrate (1), a photosensitive unit (2), a light shielding layer (4) and a first filter stack (5), A plurality of the photosensitive units (2) are arranged on the substrate (1), the light shielding layer (4) covers one of the photosensitive units (2), and the first filter stack (5) covers the light shielding layer (4). The first filter stack (5) comprises a first color filter film (51) and an infrared cutoff filter film (52) stacked together.

2. The photodiode according to claim 1, characterized in that The first filter stack (5) further comprises a first transparent substrate (53), wherein the first transparent substrate (53) is arranged above or below the stacked first color filter film (51) and the infrared cut-off filter film (52), or arranged between the first color filter film (51) and the infrared cut-off filter film (52), wherein one of the first color filter film (51) and the infrared cut-off filter film (52) is arranged above the first transparent substrate (53) and the other is arranged below the first transparent substrate (53).

3. The photodiode according to claim 2, characterized in that The first transparent substrate (53) is a glass plate or a transparent optical resin plate.

4. The photodiode according to claim 2 or 3, characterized in that: The first filter stack (5) is bonded and fixed to the light shielding layer (4) and / or the substrate (1).

5. The photodiode according to any one of claims 1 to 3, characterized in that: The first color filter film (51) is one of a red light filter film, a green light filter film, or a blue light filter film.

6. The photodiode according to any one of claims 1 to 3, characterized in that: The light shielding layer (4) is a metal layer.

7. A photodiode, characterized in that: It comprises a substrate (1), a photosensitive unit (2) and a second filter stack (8), The photosensitive unit (2) is arranged on the substrate (1), and the second filter stack (8) covers the photosensitive unit (2). The second filter stack (8) comprises a second color filter film (81) and a second infrared filter film (82) stacked together.

8. The photodiode according to claim 7, characterized in that The second filter stack (8) further comprises a second transparent substrate (83), wherein the second transparent substrate (83) is arranged above or below the stacked second color filter film (81) and the second infrared filter film (82), or arranged between the second color filter film (81) and the second infrared filter film (82), wherein one of the second color filter film (81) and the second infrared filter film (82) is arranged above the second transparent substrate (83) and the other is arranged below the second transparent substrate (83).

9. The photodiode according to claim 8, characterized in that The second transparent substrate (83) is a glass plate or a transparent optical resin plate.

10. The photodiode according to claim 8 or 9, characterized in that: The second filter stack (8) is bonded and fixed to the photosensitive unit (2) and / or the substrate (1).

11. The photodiode according to any one of claims 7 to 9, characterized in that: The second color filter film (81) is one of a red light filter film, a green light filter film, or a blue light filter film.

12. A light sensing chip, characterized in that: The photodiode comprises the photodiode according to any one of claims 1 to 11.

13. An electronic device, characterized in that: Including the photosensitive chip as described in claim 12.

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