Digital driving method and device for silicon-based liquid crystal

Abstract

This disclosure provides a digital driving method and apparatus for a silicon-based liquid crystal (SLC). The method includes: generating a first driving signal; injecting a pre-activation signal into the first driving signal to form a second driving signal, wherein the injection position of the effective level of the pre-activation signal is any position in the last quarter of each signal cycle of the first driving signal; and driving the SLC according to the second driving signal. This disclosure reduces the jitter caused by sudden high levels following long periods of low levels in the SLC by adjusting the waveform of the conventional driving signal and injecting the pre-activation signal at specific positions in its signal cycle, thereby achieving highly stable digital driving of the SLC and making the control of the light field by the SLC more stable.

Description

Technical Field

[0001] This disclosure relates to the field of digital driving technology, and in particular to a digital driving method, apparatus, silicon liquid crystal device, and electronic device for silicon-based liquid crystals. Background Technology

[0002] Liquid crystal on silicon (LCoS) technology is a display technology that combines liquid crystal materials with metal oxide semiconductor (CMOS) technology. By generating voltage through a driving circuit to deflect liquid crystal molecules at different angles, the amplitude or phase of light can be modulated by utilizing the birefringence property of liquid crystal molecules. Currently, this technology is widely used in many fields such as projection display, optical communication, laser processing, and biomedicine.

[0003] Silicon-based liquid crystal devices (LCDs) can be categorized into pure amplitude type and pure phase type based on their light modulation methods. Because liquid crystal molecules generate a transient phase jitter during voltage-driven operation, this phase jitter severely impacts the modulation effect of pure phase-based LCDs. Phase jitter affects the quality of the loaded hologram and the stability of the light field modulation; therefore, it has always been discussed as an important parameter. In wavelength-selective switching applications, phase jitter leads to inaccurate light deflection angles, resulting in increased crosstalk or information loss. In applications requiring rapid and precise pointing, phase jitter significantly affects switching speed and accuracy. Therefore, it is crucial to develop a method to reduce phase jitter and achieve highly stable liquid crystal driving. Summary of the Invention

[0004] The purpose of this disclosure is to provide a digital driving method, apparatus, device, and electronic device for silicon-based liquid crystals to solve the jitter problem in the driving of silicon-based liquid crystals in the prior art.

[0005] The embodiments of this disclosure adopt the following technical solution: a digital driving method for a silicon-based liquid crystal, comprising: generating a first driving signal; injecting a pre-activation signal into the first driving signal to form a second driving signal, wherein the injection position of the effective level of the pre-activation signal is any position in the last quarter of each signal cycle of the first driving signal; and driving the silicon-based liquid crystal according to the second driving signal.

[0006] In some embodiments, the pre-activation signal is a PWM signal with the same signal period as the first drive signal.

[0007] In some embodiments, the pulse width of the effective level of the pre-activation signal is less than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect.

[0008] This disclosure also provides a digital driving device for a silicon-based liquid crystal, comprising: a first driving circuit for generating a first driving signal; a pre-activation driving circuit for generating a pre-activation signal; and a waveform configuration circuit for injecting the pre-activation signal into the first driving signal to form a second driving signal, and driving the silicon-based liquid crystal according to the second driving signal, wherein the injection position of the effective level of the pre-activation signal is any position in the last quarter cycle of each signal cycle of the first driving signal.

[0009] In some embodiments, the pre-activation signal is a PWM signal with the same signal period as the first drive signal.

[0010] In some embodiments, the pulse width of the effective level of the pre-activation signal is less than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect.

[0011] In some embodiments, the waveform configuration circuit is configured with OR logic.

[0012] This disclosure also provides a silicon-based liquid crystal device, including: a silicon-based liquid crystal array; and a digital driving device as described above.

[0013] This disclosure also provides an electronic device, which includes at least the silicon-based liquid crystal device described above.

[0014] In some embodiments, the electronic device is any one of a wavelength selective switch, an inter-satellite optical communication port, and a display.

[0015] The beneficial effects of the embodiments disclosed herein are as follows: by adjusting the conventional driving signal waveform of the liquid crystal on silicon (LCD) and injecting a pre-activation signal at a specific position in its signal cycle, the phenomenon of the LCD jittering caused by a sudden high level after a long period of low level is reduced, thereby achieving highly stable digital driving of the LCD and making the control of the light field of the LCD more stable. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the digital driving method in the first embodiment of this disclosure;

[0018] Figure 2 This is a schematic diagram of the waveform of the first driving signal in the first embodiment of this disclosure at 50% duty cycle, 25% duty cycle and 75% duty cycle;

[0019] Figure 3 This is a waveform diagram of the second driving signal in the first embodiment of this disclosure;

[0020] Figure 4 This is a schematic diagram of the structure of the digital drive device in the second embodiment of this disclosure. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0022] Liquid crystal on silicon (LCoS) technology is a display technology that combines liquid crystal materials with metal oxide semiconductor technology. By generating voltage through a driving circuit to deflect liquid crystal molecules at different angles, the amplitude or phase of light can be modulated by utilizing the birefringence property of liquid crystal molecules. Currently, this technology is widely used in many fields such as projection display, optical communication, laser processing, and biomedicine.

[0023] Silicon-based liquid crystal devices (LCDs) can be categorized into pure amplitude type and pure phase type based on their light modulation methods. Because liquid crystal molecules generate a transient phase jitter during voltage-driven operation, this phase jitter severely impacts the modulation effect of pure phase-based LCDs. Phase jitter affects the quality of the loaded hologram and the stability of the light field modulation; therefore, it has always been discussed as an important parameter. In wavelength-selective switching applications, phase jitter leads to inaccurate light deflection angles, resulting in increased crosstalk or information loss. In applications requiring rapid and precise pointing, phase jitter significantly affects switching speed and accuracy. Therefore, it is crucial to develop a method to reduce phase jitter and achieve highly stable liquid crystal driving.

[0024] To address the aforementioned issues, the first embodiment of this disclosure provides a digital driving method for silicon-based liquid crystals (LCoS). The voltage driving methods for LCoS devices can be categorized into digital driving and analog driving. Currently, most LCoS devices employ a low-power, low-cost digital driving method to change the modulation phase. Pulse Width Modulation (PWM) is used to control the liquid crystal. By adjusting the duty cycle of the PWM waveform, the root mean square (RMS) voltage of the driving signal is changed, thereby controlling the liquid crystal to achieve different grayscale phase responses. However, traditional PWM waveforms may contain prolonged low-level periods. A sudden application of a high level can cause jitter in the instantaneous response of the liquid crystal, resulting in holographic flickering and unstable light field modulation.

[0025] Figure 1 A flowchart of the digital driving method of this embodiment is shown, such as... Figure 1 As shown, the digital driving method in this embodiment mainly includes the following steps:

[0026] S10 generates the first drive signal.

[0027] In this embodiment, the first driving signal refers to a PWM signal generated according to the current deflection requirement of the liquid crystal state of the silicon-based liquid crystal. By adjusting the duty cycle of the effective level of the first driving signal, the RMS voltage of the driving signal is changed, thereby controlling the deflection state of the liquid crystal. It should be understood that the generation of the first driving signal can be achieved according to conventional PWM signal generation methods, and the specific generation process is not limited to this embodiment.

[0028] In this embodiment, a high level is used as the valid signal for the PWM signal. Figure 2 The waveforms of the first drive signal at 50% duty cycle, 25% duty cycle, and 75% duty cycle are shown.

[0029] S20, a pre-activation signal is injected into the first drive signal to form the second drive signal.

[0030] Combination Figure 2 The waveform diagram of the first driving signal shown shows that there is a long low-level phase between the high level of each cycle and the high level of the previous cycle. When the effective level of the next cycle is suddenly applied, the sudden change in electric field will cause the liquid crystal to jitter in the instantaneous response. Therefore, this embodiment injects a pre-activation signal in the first driving signal to shorten the duration of the low level before the effective level arrives.

[0031] Specifically, the pre-activation signal in this embodiment is also a PWM signal. By applying the effective level in the pre-activation signal, the liquid crystal can be put into a pre-activation state. When the effective level of the first driving signal is applied in the pre-activation state, the jitter phenomenon caused by the sudden electric field applied to the liquid crystal will be significantly reduced, thereby effectively improving the driving effect of the liquid crystal.

[0032] In practical implementation, the effective level of the pre-activation signal is injected at any position within the last quarter of each signal cycle of the first driving signal, ensuring that the liquid crystal is in a pre-activated state when the next effective level of the first driving signal arrives. In some embodiments, the signal cycle of the pre-activation signal can be the same as the signal cycle of the first driving signal, so that when the pre-activation signal is injected into the first driving signal, the effective level of the pre-activation signal in each signal cycle can be within the last quarter of the first driving signal's cycle. It should be noted that during actual injection, it is also necessary to ensure that there is a low-level signal with a certain pulse width between the effective level of the pre-activation signal input in the current signal cycle and the effective level of the first driving signal in the next signal cycle, to prevent the high level of the pre-activation signal in adjacent signal cycles from merging with the high level of the first driving signal into a single high level, thus losing the pre-activation function of the pre-activation signal.

[0033] Figure 3 The waveform of the second drive signal formed after the injection of the pre-activation signal is shown, in which... Figure 3 (a) shows the waveform of the second drive signal when the effective level duty cycle of the first drive signal is 50%. Figure 3 (b) shows the waveform of the second drive signal when the effective level duty cycle of the first drive signal is 25%. Figure 3 (c) shows the waveform of the second drive signal when the effective level duty cycle of the first drive signal is 75%. Based on Figure 3 The waveform diagram shown demonstrates that the application of the pre-activation signal effectively shortens the low-level duration before the high level of the first driving signal, effectively reducing the liquid crystal jitter caused by this factor, making the hologram of the silicon-based liquid crystal more stable, and achieving stable light control.

[0034] It is worth noting that the purpose of applying the pre-activation signal is only to activate the state of the liquid crystal, rather than to cause it to flip through the application of a high level. Therefore, the pulse width of the pre-activation signal needs to be smaller than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect, in order to prevent an excessively wide pre-activation pulse from affecting the normal flipping effect of the liquid crystal.

[0035] It should be noted that, given that the pre-activation signal is also a PWM signal, it can be generated in the same way as the first drive signal. In actual generation, it is only necessary to ensure that the signal periods of the two are consistent.

[0036] S30 drives the silicon-based liquid crystal according to the second driving signal.

[0037] After injecting the pre-activation signal into the first drive signal, it can generate such as Figure 3 The second driving signal shown is input to the pixel electrode of the liquid crystal when actually driving the silicon-based liquid crystal. This creates an electric field between the pixel electrode and the common electrode, thereby controlling the flip state of the liquid crystal and achieving light modulation.

[0038] This embodiment adjusts the waveform of the conventional driving signal of a liquid crystal on silicon (LCD) and injects a pre-activation signal at a specific position in its signal cycle. This reduces the jitter caused by sudden high levels after prolonged low levels, achieving highly stable digital driving of the LCD and making its control over the light field more stable. In wavelength selective switching applications, stable light field control reduces transient crosstalk at the port, minimizing information loss. In beam shaping applications, reduced LCD jitter results in more stable holograms, thus maintaining stable beam morphology. In inter-satellite optical communication applications, stable light field control enables rapid and stable inter-satellite link establishment. In optical tweezers applications in the biomedical field, stable light field control enables precise and stable control of particles. It can also be applied to the stable driving of LCDs, achieving superior display effects.

[0039] Based on the same inventive concept, the second embodiment of this disclosure provides a digital driving device for silicon-based liquid crystals, used to realize state control of silicon-based liquid crystal devices. Figure 4 A schematic diagram of the structure of the digital driving device of this embodiment is shown. It mainly includes a first driving circuit 10 for generating a first driving signal; a pre-activation driving circuit 20 for generating a pre-activation signal; and a waveform configuration circuit 30 for injecting the pre-activation signal into the first driving signal to form a second driving signal, and driving the silicon-based liquid crystal according to the second driving signal. The injection position of the effective level of the pre-activation signal is any position in the last quarter cycle of each signal cycle of the first driving signal.

[0040] In this embodiment, both the first driving signal and the pre-activation signal are PWM signals with the same signal period. By applying the effective level of the pre-activation signal, the liquid crystal can be put into a pre-activated state. In the pre-activated state, when the effective level of the first driving signal is applied, the jitter phenomenon caused by the sudden electric field applied to the liquid crystal will be significantly reduced, thus effectively improving the driving effect of the liquid crystal. At this time, the first driving circuit 10 and the pre-activation driving circuit 20 can have completely identical circuit structures. Both are circuits used to generate PWM signals, and conventional PWM signal generation circuits can be used. This embodiment does not limit the specific circuit structure, as long as it can meet the requirements of PWM signal generation.

[0041] The waveform configuration circuit 30 can inject a pre-activation signal into the first driving signal through logical operations, signal superposition, or modulation. In some embodiments, the waveform configuration circuit 30 is configured with an OR logic gate, that is, with the first driving signal and the pre-activation signal as the two inputs of the OR gate, if either the first driving signal or the pre-activation signal is at a valid level, the corresponding output second driving signal is also at a valid level. Alternatively, the waveform configuration circuit 30 can also be a microcontroller (MCU) or a dedicated integrator for PWM signals, as long as it can achieve the second driving signal output required in this embodiment.

[0042] It is worth noting that the purpose of applying the pre-activation signal is only to activate the state of the liquid crystal, and not to cause the state to flip by applying a high level. Therefore, the pulse width of the pre-activation signal output by the pre-activation driving circuit 20 needs to be smaller than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect, so as to prevent the excessively wide pre-activation pulse from affecting the normal flipping effect of the liquid crystal.

[0043] At the same time, the output of the waveform configuration circuit 30 is connected to the driving end of the silicon-based liquid crystal to realize the formation of a control electric field between the pixel electrode and the common electrode, so as to control the flip state of the liquid crystal and realize the modulation of light.

[0044] This embodiment adjusts the waveform of the conventional driving signal of a liquid crystal on silicon (LCD) and injects a pre-activation signal at a specific position in its signal cycle. This reduces the jitter caused by sudden high levels after prolonged low levels, achieving highly stable digital driving of the LCD and making its control over the light field more stable. In wavelength selective switching applications, stable light field control reduces transient crosstalk at the port, minimizing information loss. In beam shaping applications, reduced LCD jitter results in more stable holograms, thus maintaining stable beam morphology. In inter-satellite optical communication applications, stable light field control enables rapid and stable inter-satellite link establishment. In optical tweezers applications in the biomedical field, stable light field control enables precise and stable control of particles. It can also be applied to the stable driving of LCDs, achieving superior display effects.

[0045] Based on the same inventive concept, the third embodiment of this disclosure provides a silicon-based liquid crystal device, which should at least include a silicon-based liquid crystal array and a digital driving device as provided in the second embodiment of this disclosure. That is, the silicon-based liquid crystal array is controlled by the second driving signal output by the digital driving device, reducing the phenomenon of silicon-based liquid crystal jitter caused by sudden high level after long period of low level, realizing highly stable silicon-based liquid crystal digital driving, and enabling the silicon-based liquid crystal device to control the light field more stably.

[0046] Based on the same inventive concept, the fourth embodiment of this disclosure provides an electronic device, which should at least include the silicon-based liquid crystal device provided in the third embodiment of this disclosure. This electronic device can be any one of a wavelength-selective switch, an inter-satellite optical communication port, or a display. This embodiment adjusts the conventional driving signal waveform of the silicon-based liquid crystal device and injects a pre-activation signal at a specific position in its signal cycle. This reduces the jitter caused by a sudden high level after a long period of low level, achieving highly stable digital driving of the silicon-based liquid crystal device and enabling more stable control of the light field. In wavelength-selective switch applications, stable light field control can reduce transient crosstalk at the port and reduce information loss; in beam shaping applications, reduced liquid crystal jitter makes the generated hologram more stable, thereby maintaining the stability of the beam morphology; in inter-satellite optical communication applications, stable light field control enables rapid and stable inter-satellite link establishment; in optical tweezers applications in the biomedical field, stable light field control enables precise and stable control of particles; it can also be applied to the stable driving of liquid crystal displays to achieve better display effects.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A digital driving method for silicon-based liquid crystals, characterized in that, include: Generate the first drive signal; A pre-activation signal is injected into the first driving signal to form a second driving signal. The effective level of the pre-activation signal is injected at any position in the last quarter of each signal cycle of the first driving signal, and there is a low-level signal with a certain pulse width between the effective level of the pre-activation signal input in the current signal cycle and the effective level of the first driving signal in the next signal cycle. The silicon-based liquid crystal is driven according to the second driving signal.

2. The digital driving method according to claim 1, characterized in that, The pre-activation signal is a PWM signal with the same signal period as the first drive signal.

3. The digital driving method according to claim 1 or 2, characterized in that, The pulse width of the effective level of the pre-activation signal is less than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect.

4. A digital driving device for silicon-based liquid crystals, characterized in that, include: A first driving circuit is used to generate a first driving signal; A pre-activation drive circuit is used to generate a pre-activation signal; A waveform configuration circuit is used to inject the pre-activation signal into the first driving signal to form a second driving signal, and drive the silicon-based liquid crystal according to the second driving signal. The injection position of the effective level of the pre-activation signal is any position in the last quarter of each signal cycle of the first driving signal, and there is a low-level signal with a certain pulse width between the effective level of the pre-activation signal input in the current signal cycle and the effective level of the first driving signal in the next signal cycle.

5. The digital drive device according to claim 4, characterized in that, The pre-activation signal is a PWM signal with the same signal period as the first drive signal.

6. The digital drive device according to claim 4, characterized in that, The pulse width of the effective level of the pre-activation signal is less than the minimum pulse width required to drive the liquid crystal state of the silicon-based liquid crystal to deflect.

7. The digital drive device according to any one of claims 4 to 6, characterized in that, The waveform configuration circuit is configured with OR logic.

8. A silicon-based liquid crystal device, characterized in that, include: Silicon-based liquid crystal array; The digital drive device as described in any one of claims 4 to 7.

9. An electronic device, characterized in that, It includes at least the silicon-based liquid crystal device as described in claim 8.

10. The electronic device according to claim 9, characterized in that, The electronic device is any one of a wavelength selective switch, an inter-satellite optical communication port, and a display.

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