CN116045222A - Electronic equipment - Google Patents

Abstract

The present disclosure provides an electronic device, at least comprising: a base; the light guide plate is arranged on one side surface of the base, and N invisible light sources are arranged on the periphery of the light guide plate; the wavelengths of the invisible light emitted by the N invisible light sources are different, the light guide plate is configured to emit light rays which are emitted into the light guide plate from a first surface and/or a second surface of the light guide plate, the first surface is a surface of the light guide plate close to the base, and the second surface is a surface of the light guide plate far away from the base; the first surface of the light guide plate is provided with a luminescent ink layer, and the luminescent ink layer emits visible light with different colors under the excitation of invisible light with different wavelengths, so that the visible light is emitted from the second surface of the light guide plate; the shell is arranged on one side of the light guide plate far away from the base and is fixedly connected with the base in a clamping way, and at least a first window is arranged on the shell, so that visible light is emitted from the first window and displayed. The invisible light source is arranged on the periphery of the light guide plate, so that the occupied space is small, and the light guide plate is suitable for small-sized electronic equipment.

Description

Electronic equipment

Technical Field

The disclosure relates to the technical field of display, and in particular relates to electronic equipment.

Background

Many electronic devices are configured with corresponding fingerprint recognition functions for security. The general electronic device adopts a structural form of a light-emitting module (such as an LED module) to feed back fingerprint identification results, such as a door handle, a notebook computer power button and the like. The conventional practice is to install the lamp ring around the button, switch on the point source when the finger contacts corresponding position, the lamp ring lights a certain color after the fingerprint identification is successful, if the fingerprint identification fails, the lamp ring lights another color as warning. The method has certain defects, such as the installation of the light-emitting module requires a larger space, the hand-held small electronic equipment with limited space is limited by the self structural space, the light-emitting module with various colors cannot be arranged, and the light-emitting mode of the small electronic equipment is single and the user experience is poor.

Disclosure of Invention

An objective of the disclosed embodiments is to provide an electronic device, which is used for solving the problem of single lighting mode of small and medium-sized handheld devices in the prior art.

The embodiment of the disclosure adopts the following technical scheme: electronic device, comprising at least:

a base;

the light guide plate is arranged on one side surface of the base, and N invisible light sources are arranged on the periphery of the light guide plate; the light guide plate is configured to emit light rays emitted into the light guide plate from a first surface and/or a second surface of the light guide plate, wherein the first surface is a surface of the light guide plate close to a base, and the second surface is a surface of the light guide plate far away from the base;

the first surface of the light guide plate is provided with a luminescent ink layer, and the luminescent ink layer emits visible light with different colors under the excitation of invisible light with different wavelengths, so that the visible light is emitted from the second surface of the light guide plate;

the shell is arranged on one side of the light guide plate far away from the base and is fixedly connected with the base in a clamping way, and at least a first window is arranged on the shell, so that the visible light is emitted from the first window and displayed.

In some embodiments, the invisible light source comprises at least: an ultraviolet light source and/or an infrared light source.

In some embodiments, the N non-visible light sources are LEDs and/or minileds.

In some embodiments, the first surface of the light guide plate is provided with a texture corresponding to the position of the luminescent ink layer, and the texture is used for emitting the light rays entering the light guide plate from the first surface and/or the second surface of the light guide plate.

In some embodiments, the first surface of the light guide plate is provided with a light-shielding ink layer, and the light-shielding ink layer covers an area on the first surface of the light guide plate where the light-emitting ink layer is not provided.

In some embodiments, the housing further includes a panel, a first face of the panel abutting a second face of the light guide plate, the second face of the panel being an exterior face of the electronic device, the second face of the panel being a face opposite the first face of the panel.

In some embodiments, the electronic device further comprises:

the fingerprint acquisition module is configured to acquire fingerprints;

the controller is configured to form a fingerprint collection image from the fingerprints collected by the fingerprint collection module, and compare whether the fingerprint collection image is identical with a preset fingerprint image or not;

under the condition that the fingerprint acquisition image is the same as a preset fingerprint image, the controller drives one of the invisible light sources to emit invisible light;

and under the condition that the fingerprint acquisition image is different from the preset fingerprint image, the controller drives the other invisible light source to emit the other invisible light.

In some embodiments, the fingerprint collection module is disposed between the base and the light guide plate, and the fingerprint collection module is located opposite to the luminescent ink layer.

In some embodiments, the electronic device further comprises at least one visible light source located at the periphery of the light guide plate, wherein the visible light emitted by the visible light source enters the light guide plate and exits from the second face of the light guide plate, and the visible light emitted by the visible light source is different from the visible light emitted by the luminescent ink layer under the excitation of invisible light with different wavelengths.

In some embodiments, the electronic device further comprises:

the sensing unit is configured to identify the environmental light intensity of the environment in which the electronic equipment is located;

the controller is further configured to drive the visible light source to emit visible light when the sensing unit recognizes that the ambient light intensity is less than a first preset light intensity.

The beneficial effects of the embodiment of the disclosure are that:

through setting up the light guide plate on the base to set up the periphery at the light guide plate with N kind of invisible light source, utilize the invisible light of different wavelength to cooperate the luminous printing ink layer to realize the presentation of different colours visible light, need not to use too much visible light source to carry out the demonstration of multiple colour, realized the realization of multiple luminescence mode of electronic equipment on the basis of reducing the occupation in electronic equipment space, reached the purpose that richens user's use experience.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

Fig. 1 is a schematic diagram of a split structure of an electronic device of the present disclosure;

fig. 2 is a schematic diagram of the invisible light source and the relative positional relationship between the visible light source and the light guide plate, and the principle of reflection of light emitted by the invisible light source and the visible light source;

FIG. 3 is a schematic view of the structure of a light guide plate and a steel plate mold when the texture of the light guide plate is formed by the steel plate mold;

fig. 4 is a schematic structural diagram of an electronic device of the present disclosure in a top view;

FIG. 5 is a schematic view of a portion of the electronic device of FIG. 4 in section view A-A of the present disclosure;

fig. 6 is a schematic view of a part of the structure of the electronic device in the section view B-B in fig. 4 of the present disclosure.

Reference numerals: 1. a base; 2. a light guide plate; 3. a housing; 4. a first face; 5. a second face; 6. texture; 7. a steel plate die; 8. a panel; 9. a fingerprint acquisition module; 10. a metal sheet; 11. a short wave ultraviolet light LED; 12. a long-wave ultraviolet light LED; 13. a short wave ultraviolet light emitting ink layer; 14. a long-wave ultraviolet light-emitting ink layer; 15. a white light LED;

Detailed Description

Various aspects and features of the disclosure are described herein with reference to the drawings.

It should be understood that various modifications may be made to the embodiments of the application herein. Therefore, the above description should not be taken as limiting, but merely as exemplification of the embodiments. Other modifications within the scope and spirit of this disclosure will occur to persons of ordinary skill in the art.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

These and other characteristics of the present disclosure will become apparent from the following description of a preferred form of embodiment, given as a non-limiting example, with reference to the accompanying drawings.

It is also to be understood that, although the disclosure has been described with reference to some specific examples, a person skilled in the art will certainly be able to achieve many other equivalent forms of the disclosure, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

The above and other aspects, features and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings.

Specific embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known and/or repeated functions and constructions are not described in detail to avoid obscuring the disclosure in unnecessary or unnecessary detail. Therefore, specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

The specification may use the word "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may each refer to one or more of the same or different embodiments in accordance with the disclosure.

For some small electronic devices, the fingerprint recognition result cannot be fed back in the form of a light-emitting module due to the limitation of the self structural space. In particular, for the electronic equipment adopting the ultrasonic fingerprint acquisition module, an integral panel is adopted, the ultrasonic fingerprint acquisition module is exposed from the opening part of the metal sheet arranged on the base, and in order to ensure that the ultrasonic fingerprint acquisition module can sensitively acquire fingerprints, the ultrasonic fingerprint acquisition module needs to be clung to the panel, so that a space for placing the luminous module is not reserved between the ultrasonic fingerprint identification module and the panel.

In view of the foregoing, the disclosure provides an electronic device, as shown in fig. 1, the electronic device at least includes a base 1, a light guide plate 2 is disposed on a surface of one side of the base 1, a housing 3 is disposed on a side of the light guide plate 2 away from the base 1, and the housing 3 is fastened on the base 1. N kinds of invisible light sources are provided on the outer periphery of the light guide plate 2, and the N kinds of invisible light sources are provided at spatial positions between the outer periphery of the light guide plate 2 and the inner wall of the housing 3. The wavelengths of the invisible light emitted by the N invisible light sources are different, namely, the invisible light source corresponding to one invisible light source can only emit the invisible light with one wavelength. Fig. 2 is a schematic diagram showing the relative positions of the invisible light source and the light guide plate 2, in which the light emitting region of the invisible light source is opposite to the outer periphery of the light guide plate 2, so that the invisible light emitted from the invisible light source is emitted into the light guide plate 2 from the outer periphery of the light guide plate 2 as much as possible, and the light guide plate 2 emits the incident invisible light from the first surface 4 and/or the second surface 5 of the light guide plate 2. The first surface 4 is a surface of the light guide plate 2 near the base 1, and the second surface 5 is a surface of the light guide plate 2 far away from the base 1, and the invisible light emitted from the second surface 5 of the light guide plate 2 cannot be perceived by a user of the electronic device because the invisible light is emitted by the invisible light source. The first surface 4 of the light guide plate 2 is provided with a luminescent ink layer which emits different colors of visible light under excitation by different wavelengths of invisible light emitted from the first surface 4 of the light guide plate 2. Visible light excited by the luminescent ink layer is emitted from the second surface 5 of the light guide plate 2.

In combination with the light guide plate 2 and the invisible light source, the housing 3 is provided with at least one first window, so that the visible light is emitted from the first window and displayed, and a pattern corresponding to one color is displayed corresponding to the visible light of one color. If a screen is arranged on the base 1 of the electronic device, a second window is arranged on the light guide plate 2 corresponding to the position of the screen, namely, a notch with the size corresponding to the screen is arranged on the light guide plate 2, and the notch is used as the second window. The shell 3 can be made of hard plastic materials, the shell 3 has certain elasticity, and the shell 3 is clamped and fixed on the base 1 during installation. In addition, the outer edge angular position of the housing 3 can be chamfered, on the one hand preventing the housing 3 from scraping the user of the electronic device, and on the other hand being more attractive.

Through setting up the light guide plate on the base to set up the periphery at the light guide plate with N kind of invisible light source, utilize the invisible light of different wavelength to cooperate the luminous printing ink layer to realize the presentation of different colours visible light, need not to use too much visible light source to carry out the demonstration of multiple colour, realized the realization of multiple luminescence mode of electronic equipment on the basis of reducing the occupation in electronic equipment space, reached the purpose that richens user's use experience. On the basis, all invisible light sources are arranged on the same plane as much as possible in order to reduce the occupied space as much as possible. In addition, only one invisible light source can be arranged correspondingly, so that the occupied space is reduced as much as possible. If the space of the electronic device is relatively abundant, two or more invisible light sources can be arranged corresponding to one invisible light source, and the specific number can be adjusted according to the structural size of the electronic device.

In some embodiments, the invisible light source comprises at least: ultraviolet light sources and/or infrared light sources are more stable than infrared light sources, and may be preferred. In particular, LEDs and/or minleds may be employed as the invisible light source.

In some embodiments, the luminescent ink layer is formed by single-layer coating, the thickness of the coating is about 10 μm to 15 μm, the limited space of the product is utilized as much as possible, and the power consumption and the cost of the luminescent device are reduced. The luminescent ink used in the luminescent ink layer is a special ink which is irradiated by ultraviolet light with the wavelength of 200nm-400nm to excite visible light with the wavelength of 400nm-780 nm. In some embodiments, a short wavelength ultraviolet light emitting ink having an excitation wavelength of 254nm and a long wavelength ultraviolet light emitting ink having an excitation wavelength of 365nm may be used, the two wavelengths of ultraviolet light emitting ink being relatively stable; a mixed luminescent ink may be used, and the luminescent ink layer formed on the light guide plate by the mixed luminescent ink may be excited to emit different colors of visible light by different wavelengths of invisible light. The luminescent ink layer formed on the light guide plate 2 by the short-wave ultraviolet light luminescent ink is stimulated to emit green light with the wavelength of 577nm-492 nm; the luminescent ink layer formed on the light guide plate 2 using the long-wave ultraviolet light luminescent ink is excited to emit red light having a wavelength of 622nm to 760 nm. The organic photosensitive fluorescent toner in the luminescent ink is excited and emits visible light, and the color of the visible light depends on the organic photosensitive fluorescent toner in the luminescent ink.

In some embodiments, the specific implementation manner of the emission of the invisible light from the light guide plate 2 is: corresponding textures 6 are arranged on the first surface 4 of the light guide plate 2 corresponding to the luminous ink layer, and light rays entering the light guide plate 2 are reflected by the textures 6 and emitted from the first surface 4 and/or the second surface 5 of the light guide plate 2. The specific design form of the texture 6 may be formed by pits protruding from the first surface 4 of the light guide plate 2 toward the second surface 5 of the light guide plate 2, and the texture 6 formed by pits corresponds to the position and shape of the luminescent ink layer.

In some embodiments, a fully transparent plastic plate may be used as the light guide plate 2, such as a fully transparent PC plate (polyester plate), and for such a material of the light guide plate 2, as shown in fig. 3, the design of the texture 6 on the first surface 4 of the light guide plate 2 may be directly hot-stamped by a steel plate mold 7, and one surface of the steel plate mold 7 has bumps corresponding to the texture 6. The light guide plate 2 may also be made of a completely transparent glass, and if a completely transparent glass material is used, the design of the texture 6 on the first surface 4 of the light guide plate 2 may be formed by laser engraving. The light guide plate 2 is made of a fully transparent glass material, and the fully transparent plastic plate is better in effect. Because the full transparent plastic plate has certain flexibility, the material is softer, and the processing of being convenient for, in addition to this, have following effect: in the use process, breakage and the like are not easy to occur, and the service life of the electronic equipment is longer.

The bumps can be combined to form different patterns, such as a fingerprint pattern, a ring pattern, a dot pattern and the like, according to the needs of a user, and the electronic equipment can select one or two or more of the patterns. The same color of visible light may correspond to a single pattern, or may correspond to two or more patterns. For example, when a mixed luminescent ink layer is used, the visible light emitted by the luminescent ink layer is excited to correspond to the same pattern.

In some embodiments, the first surface 4 of the light guide plate 2 is further provided with a shading ink layer, which is not correspondingly shown in fig. 2 due to its small thickness; the light-shielding ink layer covers the area of the light guide plate 2 where the light-emitting ink layer is not provided. The shading ink layer is used for shading an electronic device arranged on the base 1 and located between the light guide plate 2 and the base 1 and an area between the base 1 and the light guide plate 2, so that the appearance effect of the electronic device is improved.

In addition to the above-described structure of the light guide plate 2, in order to improve the aesthetic appearance and wear resistance of the electronic device, a panel 8 is disposed at the second surface of the light guide plate 2, and the panel 8 may be a part of the housing 3. The first surface of the panel 8 abuts against the second surface 5 of the light guide plate 2, the second surface of the panel 8 serves as an exterior surface of the electronic device, and the second surface of the panel 8 is a surface opposite to the first surface of the panel 8. The panel 8 may be a translucent plastic plate, and in particular a translucent acrylic plate (PMMA plate) may be used. The acrylic plate is harder than the polyester plate, and the panel 8 serving as the electronic equipment is not easily scratched; and the surface of the acrylic plate is easy to process into a smooth surface as an appearance surface, so that the use feeling of a user on the electronic equipment is improved. During production, the fully transparent PC board and PMMA board can be extruded into a composite board, the thickness is about 0.8 mm, the specific thickness can be set according to the structural size of an electronic product, and the thinner composite board utilizes the limited space of electronic equipment as much as possible.

Fingerprint identification in this disclosure is realized through fingerprint collection module 9 and controller cooperation. Specifically, the fingerprint collection module 9 sets up between base 1 and light guide plate 2, passes sheetmetal 10 position opening parts and exposes, and the position of fingerprint collection module 9 just is to the position on luminous ink layer, and the user of being convenient for can be quick find the position that needs to carry out fingerprint identification, improves user's use experience and feels. The fingerprint identification module is configured to be used for gathering fingerprint. The controller is configured to form a fingerprint collection image from the fingerprints collected by the fingerprint collection module, and compare whether the fingerprint collection image is identical to a preset fingerprint image; under the condition that the fingerprint acquisition image is the same as the preset fingerprint image, the controller drives one of the invisible light sources to emit invisible light; under the condition that the fingerprint collection image is different from the preset fingerprint image, the controller drives the other invisible light source to emit the other invisible light.

In order to clearly express the working principle of the fingerprint acquisition module and the controller, the fingerprint acquisition module and the controller are described by combining specific types of invisible light. Taking two types of invisible light sources as examples, one type of invisible light source is used for correspondingly emitting short-wave ultraviolet light, a short-wave ultraviolet light LED11 is used, and the other type of invisible light source is used for correspondingly emitting long-wave ultraviolet light, and a long-wave ultraviolet light LED12 is used. Correspondingly, a short-wave ultraviolet light luminous ink layer 13 is arranged on the first surface 4 of the light guide plate 2 corresponding to the short-wave ultraviolet light, and a long-wave ultraviolet light luminous ink layer 14 is arranged corresponding to the long-wave ultraviolet light. The short-wave ultraviolet light luminous ink layer 13 emits green visible light after being excited by the short-wave ultraviolet light, and the green visible light is displayed after being emitted from the first window; the long-wavelength ultraviolet light emitting ink layer 14 emits red visible light when excited by the long-wavelength ultraviolet light, and the red visible light is emitted from the first window and displayed. When the comparison result of the processing unit is successful, the controller drives the short-wave ultraviolet light LED11 to emit short-wave ultraviolet light; when the comparison result of the processing unit is unsuccessful, the controller drives the long-wave ultraviolet light LED12 to emit long-wave ultraviolet light, so that the fingerprint identification result is clearly and definitely displayed to the user.

On the basis of the structure of the electronic equipment, in order to facilitate the user to clearly see the position pressed by the fingerprint under the condition of weaker environmental light intensity, the use feeling of the user is improved, and the electronic equipment is also provided with at least one visible light source. The visible light sources are also located at the periphery of the light guide plate 2, and only one visible light source can be provided, and a plurality of visible light sources can be provided as required to improve the illumination effect. In fig. 2, in order to show the principle of reflection after the light emission of the visible light source and the invisible light source, the visible light source and the invisible light source are staggered, and fig. 4 to 6 show the actual positional relationship between the invisible light source and the visible light source, in fact, the visible light source and the invisible light source are in the same plane, so as to reduce the occupation of the space of the electronic device as much as possible, reduce the power consumption and reduce the cost of the light emitting device. Visible light emitted from the visible light source is incident into the light guide plate 2 from the outer periphery of the light guide plate 2 and is emitted from the second surface 5 of the light guide plate 2. The visible light emitted by the visible light source is different from the visible light emitted by the luminous ink layer under the excitation of invisible light with different wavelengths.

The above-mentioned visible light source may be a white LED15 or an LED of another color, and the following description will take the example that the visible light source emits white visible light. White visible light emitted from the white LED15 is incident on the light guide plate 2 and then emitted from the second surface 5. In order to achieve the above-mentioned visible light source lighting effect of the electronic device, the electronic device further includes a sensing unit. The sensing unit is configured to identify an ambient light intensity of an environment in which the electronic device is located; the sensing unit may employ a light intensity sensor. The electronic device further comprises a controller configured to drive the visible light source to emit white visible light when the light intensity sensor recognizes that the ambient light intensity is smaller than the first preset light intensity (representing that the ambient light intensity is weaker). When the light intensity sensor recognizes that the ambient light intensity is equal to or higher than the first preset light intensity (representing that the ambient light intensity is stronger), the visible light source does not emit light. The first preset light intensity can be set according to actual needs.

The electronic equipment can only display one corresponding color, and when the light intensity is stronger (greater than or equal to the first preset light intensity), the electronic equipment displays the gray of the luminous ink layer; when the light intensity is weak (less than the first preset light intensity), the electronic device displays white light emitted by the white light LED 15; when the fingerprint identification is successful, the electronic equipment displays green visible light excited by the luminous ink layer; when the fingerprint identification is unsuccessful, the electronic equipment displays red visible light excited by the luminous ink layer. The visible light with different corresponding colors corresponds to different states of the electronic equipment, so that the feedback of the fingerprint identification result is realized, and the use experience of a customer is improved.

While various embodiments of the present disclosure have been described in detail, the present disclosure is not limited to these specific embodiments, and various modifications and embodiments can be made by those skilled in the art on the basis of the concepts of the present disclosure, and these modifications and modifications should be within the scope of the present disclosure as claimed.

Claims (10)

1. An electronic device, comprising at least:

a base;

the light guide plate is arranged on one side surface of the base, and N invisible light sources are arranged on the periphery of the light guide plate; the light guide plate is configured to emit light rays emitted into the light guide plate from a first surface and/or a second surface of the light guide plate, wherein the first surface is a surface of the light guide plate close to a base, and the second surface is a surface of the light guide plate far away from the base;

the first surface of the light guide plate is provided with a luminescent ink layer, and the luminescent ink layer emits visible light with different colors under the excitation of invisible light with different wavelengths, so that the visible light is emitted from the second surface of the light guide plate;

the shell is arranged on one side of the light guide plate far away from the base and is fixedly connected with the base in a clamping way, and at least a first window is arranged on the shell, so that the visible light is emitted from the first window and displayed.

2. The electronic device of claim 1, wherein the invisible light source comprises at least: an ultraviolet light source and/or an infrared light source.

3. The electronic device of claim 1, wherein N types of the invisible light sources are LEDs and/or minileds.

4. The electronic device according to claim 1, wherein the first surface of the light guide plate is provided with a texture corresponding to the position of the luminescent ink layer, and the texture is used for emitting light rays entering the light guide plate from the first surface and/or the second surface of the light guide plate.

5. The electronic device of claim 1, wherein the first face of the light guide plate is provided with a light-blocking ink layer that covers an area of the first face of the light guide plate where the light-emitting ink layer is not provided.

6. The electronic device of claim 1, wherein the housing further comprises a panel, a first face of the panel abutting a second face of the light guide plate, the second face of the panel being an exterior face of the electronic device, the second face of the panel being a face opposite the first face of the panel.

7. The electronic device of any one of claims 1-6, wherein the electronic device further comprises:

the fingerprint acquisition module is configured to acquire fingerprints;

the controller is configured to form a fingerprint collection image from the fingerprints collected by the fingerprint collection module, and compare whether the fingerprint collection image is identical with a preset fingerprint image or not;

under the condition that the fingerprint acquisition image is the same as a preset fingerprint image, the controller drives one of the invisible light sources to emit invisible light;

and under the condition that the fingerprint acquisition image is different from the preset fingerprint image, the controller drives the other invisible light source to emit the other invisible light.

8. The electronic device of claim 7, wherein the fingerprint collection module is disposed between the base and the light guide plate, the fingerprint collection module being positioned opposite the luminescent ink layer.

9. The electronic device of claim 7, further comprising at least one visible light source located at an outer periphery of the light guide plate, wherein visible light emitted by the visible light source is incident into the light guide plate and emitted from the second face of the light guide plate, and wherein visible light emitted by the visible light source is different in color from visible light emitted by the luminescent ink layer under excitation of invisible light of a different wavelength.

10. The electronic device of claim 9, wherein the electronic device further comprises:

the sensing unit is configured to identify the environmental light intensity of the environment in which the electronic equipment is located;

the controller is further configured to drive the visible light source to emit visible light when the sensing unit recognizes that the ambient light intensity is less than a first preset light intensity.

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