This application claims the priority benefit of China application serial no. 202310674617.0, filed on Jun. 8, 2023. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
The disclosure relates to a projection device and a method, and in particular, relates to a projection device and a driving method of the projection device.
For a laser projector, a plurality of micro-reflectors on a digital micro-mirror device (DMD) are used most of the time to project a laser beam onto a target area. In order to average the damage of use of each of the micro-reflectors, the micro-reflectors are periodically flipped. Therefore, how to appropriately control the operation of a laser projector to prevent light leakage from generating when the micro-reflectors are flipped become one of the important issues to be considered when designing the laser projector.
The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.
The disclosure provides a projection device and a driving method of the projection device capable of preventing light leakage from generating effectively.
Other objects and advantages of the invention may be further illustrated by the technical features broadly embodied and described as follows.
In order to achieve the above one, part of, or all of the objects or other objects, the disclosure provides a projection device including a signal processing circuit, a driving circuit, a light-emitting module, and a discharge circuit. The signal processing circuit is configured to provide a modulation signal and a first signal. The driving circuit is coupled to the signal processing circuit and a driving node. The driving circuit is configured to generate a driving signal to the driving node according to the modulation signal. The light-emitting module is coupled to the driving circuit through the driving node. The light-emitting module is configured to receive the driving signal from the driving node to accordingly emit a laser beam. The discharge circuit is coupled to the signal processing circuit and the driving node. The discharge circuit is configured to provide a reference voltage to the driving node according to the first signal.
In order to achieve the above one, part of, or all of the objects or other objects, the disclosure further provides a driving method, and the method includes the following steps. A signal processing circuit generates modulation signal and a first signal. A driving circuit generates a driving signal to a driving node according to the modulation signal to control a light-emitting module of a projection device to emit a laser beam according to the driving signal. A discharge circuit coupled to the driving node selectively provides a reference voltage to the driving node according to the first signal.
To sum up, in the projection device and the driving method of the projection device, when the micro-reflector flips, the voltage of the driving signal provided by the driving circuit to the driving node of the light-emitting module is directly pulled down, so that the light-emitting module is immediately turned off, and light leakage is thus prevented from generating.
Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
It is to be understood that other embodiment may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.
On the other hand, the flipping signal DMDR for controlling the flipping of the micro-reflectors controls the flipping of the micro-reflectors in at flipping time interval. In the embodiment shown in
Generally, the signal processing circuit 30 is configured to provide the modulation signal PWM, the first signal En1, and the second signal En2. The driving circuit 31 is coupled to the signal processing circuit 30 and a driving node ND2, and the driving circuit 31 is configured to generate a driving signal DS to the driving node ND2 according to the modulation signal PWM. The light-emitting module 32 is coupled to the driving circuit 31 through the driving node ND2 and receives the driving signal DS through the driving node ND2, so as to accordingly emit a laser beam. The discharge circuit 33 is coupled to the signal processing circuit 30 and the driving node ND2 (in detail, the discharge circuit 33 is connected to the signal processing circuit 30 by being connected to the logic circuit 34). The discharge circuit 33 is configured to selectively provide the reference voltage (e.g., ground voltage) to the driving node ND2 according to the first signal En1. The logic circuit 34 is coupled to the signal processing circuit 30, the driving circuit 31, and the discharge circuit 33. The logic circuit 34 is configured to generate a first output signal En according to the first signal En1 and the second signal En2 and provide the first output signal En to the driving circuit 31 and the discharge circuit 33.
Compared to the circuit block diagram of
For instance, the driving circuit 31 may be, for example, a power driving circuit having a boost converter, a buck converter, or any combination of the foregoing. The driving circuit 31 may, for example, be controlled by the modulation signal PWM to generate the driving signal DS with a corresponding voltage level and/or pulse width at the output terminal. The light-emitting module 32 may be configured to emit a laser beam according to the driving signal DS provided by the driving circuit 31.
In detail, the driving circuit 31 includes a voltage conversion circuit 310, a diode 311, an inductor 312, and a capacitor 313. The voltage conversion circuit 310 may be, for example, the aforementioned boost converter or buck converter for generating the driving signal DS onto the driving node ND2 according to the modulation signal PWM and the rectification function of the diode 311, the inductor 312, and the capacitor 313. A laser diode 320 of the light-emitting module may be controlled by the voltage on the driving node ND2 to emit corresponding laser beam.
In this embodiment, the first signal En1 generated by the signal processing circuit 30 is logic 1 (e.g., high voltage level) to instruct that the voltage conversion circuit 310 is turned off (the flipping time interval of the micro-reflectors). When the first signal En1 is logic 0 (e.g., low voltage level) and the second signal En2 is logic 1 (e.g., high voltage level), the driving circuit 31 is controlled to be enabled. Further, the first output signal En generated by the logic circuit 34a indicates that the laser diode 320 emits light normally with logic 1 (e.g., high voltage level) and indicates that the laser diode 320 temporarily stops or stops emitting light with logic 0 (e.g., low voltage level). In response to the voltage level of the first output signal En, the driving circuit 31 operates normally when the first output signal En is logic 1 (e.g., high voltage level) and temporarily stops or stops providing the driving signal DS to the driving node ND2 when the first output signal En is logic 0 (e.g., low voltage level). Further, the discharge circuit 33 provides the reference voltage (e.g., ground voltage) to the driving node ND2 when the first output signal En is logic 0 (e.g., low voltage level) and disconnects the driving node ND2 from the reference voltage (e.g., ground voltage) when the first output signal En is logic 1 (e.g., high voltage level). To be more specific, when the first signal En1 is logic 0 (e.g., low voltage level) and the second signal En2 is logic 1 (e.g., high voltage level), the logic circuit 34a may generate the first output signal En of logic 1 (e.g., high voltage level), so as to instruct the driving circuit 31 to enable, provide the driving signal DS to the driving node ND2, instruct the discharge circuit 33 to be turned off, and stop supplying the reference voltage to the driving node ND2. When both the first signal En1 and the second signal En2 are logic 1 (e.g., high voltage level), the logic circuit 34 may generate the first output signal En of logic 0 (e.g., low voltage level), so as to instruct the driving circuit 31 to disable, stop supplying the driving signal DS to the driving node ND2, instruct the discharge circuit 33 to be turned on, and immediately supply the reference voltage to the driving node ND2. Simply put, a truth table about the logic circuit 34a and the operations of the discharge circuit 33 and the driving node ND2 may be organized as shown in Table 1 below.
In order to achieve the truth table logic shown in Table 1 above, the logic circuit 34a includes a plurality of logic gates, that is, a NOT gate 340 (or an inverter) and an AND gate 341. The NOT gate 340 is configured to invert the first signal En1. The AND gate 341 is configured to receive the inverted first signal En1 and the second signal En2 and perform a Boolean logic AND gate operation on the two signals to generate the first output signal En. Simply put, the logic circuit 34a uses the second signal En2 as gate control and outputs the first output signal En according to the change of the inverted first signal En1.
The discharge circuit 33 may include a switch 330, and in the switch 330, both ends are coupled between the driving node ND2 and the reference voltage (e.g., ground voltage), and a control end is used to receive the control of the first output signal En. Further, in order to achieve turning on when the first output signal En is logic 0 (e.g., low voltage level), although it is not shown in
In detail,
In this embodiment, the discharge circuit 33 may be modified, for example, to be turned on at a high voltage and turned off at a low voltage. Therefore, a truth table about the logic circuit 34b and the operations of the discharge circuit 33 and the driving node ND2 may be organized as shown in Table 2 below. To be specific, in order to control the modified discharge circuit 33, the logic circuit 34b not only generates the first output signal En to the driving circuit 31, but also provides the second output signal Enb to the modified discharge circuit 33, so as to appropriately control the discharge circuit 33 to be turned on or off within an appropriate time interval.
In order to achieve the truth table logic shown in Table 2 above, the logic circuit 34b includes a plurality of logic gates, that is, an AND gate 342 and a NOT gate 343 (or an inverter). The AND gate 342 is configured to receive the first signal En1 and the second signal En2 and perform a Boolean logic AND gate operation on the two signals to generate the second output signal Enb. The NOT gate 343 receives the second output signal Enb and is configured to invert the second output signal Enb to generate the first output signal En. Simply put, the logic circuit 34b performs a Boolean logic operation on the first signal En1 and the second signal En2 to generate the second output signal Enb and inverts the second output signal Enb to generate the first output signal En.
The discharge circuit 33 includes the switch 330. In order to achieve turning on when the second output signal Enb is logic 1 (e.g., high voltage level), the switch 330 may be implemented by a n-type metal-oxide-semiconductor transistor, for example, and its drain and source are respectively coupled to the driving node ND2 and the reference voltage (e.g., ground voltage), and the gate receives the second output signal Enb. In this way, the discharge circuit 33 may be correspondingly turned on when the second output signal Enb is logic 1 (e.g., high voltage level), so as to discharge the driving node ND2 to the level of the reference voltage (e.g., ground voltage).
In this way, the flipping time interval TR defined by the flipping signal DMDR for controlling the flipping of the micro-reflector does not have the problem that the energy storage elements (capacitor 313 and inductor 312) have not released energy, and the two obviously do not overlap. In other words, through any one of
In
In some embodiments, a person having ordinary skill in the art may modify or alter the implementation of the above circuit details. For instance, the first signal En1, the second signal En2, and the first output signal En use logic 0 or logic 1 to indicate the relationship between enabling and disabling, which can certainly be adjusted adaptively. The first signal En1 may also be logic 0 (e.g., low voltage level) to indicate the flipping time interval of the micro-reflector, and the second signal En2 may also be logic 0 (e.g., low voltage level) to instruct the driving circuit to work to provide the driving signal DS onto the driving node ND2. Therefore, the logic circuit and the discharge circuit may adjust their internal circuit structures in response to different signal configurations, which all belong to the scope of the variant embodiments of the projection device.
In view of the foregoing, in the projection device, the discharge circuit may be arranged in the driving circuit to provide the reference voltage to the driving node of the light-emitting module. The discharge circuit coupled between the driving circuit and the light-emitting module may more directly and quickly discharge the energy storage elements (capacitor and inductor) in the driving circuit, and the light leakage problem when the micro-reflector flips is effectively improved.
The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.
Number | Date | Country | Kind |
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202310674617.0 | Jun 2023 | CN | national |