Scanning device, driving condition setting method, and scanning display module
A scanning device, a driving condition setting method, and a scanning display module are provided. The scanning device includes two scanning axes capable of vibrating in a first direction and a second direction. The two scanning axes have different frequency characteristics, and the frequency characteristics of the two scanning axes satisfy that a quantity of significant peaks on a frequency characteristic curve does not exceed a set quantity in a set frequency range.
1 . A scanning device for performing raster scanning in an operating state, comprising:
two scanning axes configured to vibrate in a first direction and a second direction, the two scanning axes have different frequency characteristics, and the frequency characteristics of the two scanning axes satisfy:
a quantity of significant peaks on a frequency characteristic curve does not exceed 5 in a set frequency range of [0.6*F x 0 , 1.3*F x 0 ], wherein F x 0 is a frequency that is applied to a fast scanning axis and that has a largest amplitude in a driving signal spectrum or in a scanning trajectory response spectrum.
2 . The scanning device according to claim 1 , wherein the set frequency range is determined based on driving frequencies applied to the scanning axes.
3 . The scanning device according to claim 2 , wherein the driving frequencies comprise:
a frequency having a largest amplitude in the driving signal spectrum applied to the scanning axes, or
a frequency having a largest amplitude in the scanning trajectory response spectrum of the scanning axes.
4 . The scanning device according to claim 2 , wherein the driving frequencies applied to the two scanning axes are different.
5 . The scanning device according to claim 1 , wherein the frequency characteristic curve comprises at least one of an impedance curve, a phase curve, or a frequency amplitude response curve.
6 . The scanning device according to claim 1 , wherein the scanning device comprises at least one of an optical fiber scanner or a micro-electro-mechanical system (MEMS) scanning mirror.
7 . The scanning device according to claim 1 , wherein the scanning device is an optical fiber scanner, the two scanning axes comprise a first actuating portion and a second actuating portion, the scanning device further comprises an optical fiber cantilever, a driving frequency of the first actuating portion is smaller than that of the second actuating portion, the first actuating portion and the second actuating portion drive the optical fiber cantilever to scan along a raster trajectory, and the frequency characteristic curve comprises at least one of an impedance curve and a phase curve.
8 . The scanning device according to claim 7 , wherein the driving frequency comprises a frequency having a largest amplitude in a driving signal spectrum or a scanning trajectory response spectrum applied to the first actuating portion or the second actuating portion.
9 . The scanning device according to claim 8 , wherein the scanning trajectory response spectrum is a spectrum of a response signal generated by a sub-vibration system comprising the optical fiber cantilever and one of the first and second actuating portions, in response to a driving signal applied to the first or second actuating portion.
10 . The scanning device according to claim 9 , wherein a frequency characteristic of the sub-vibration system comprising the optical fiber cantilever and one of the first and second actuating portions satisfies: the quantity of significant peaks on at least one of an impedance curve or a phase curve does not exceed 5 in the frequency range [0.6*F x 0 , 1.3*F x 0 ]; and
a frequency difference between resonance frequencies of the second actuating portion and the optical fiber cantilever is greater than 1.2 KHz; or
a frequency difference between resonance frequencies of the second actuating portion and the optical fiber cantilever is less than 5 KHz.
11 . The scanning device according to claim 10 , wherein a frequency difference between the driving frequency corresponding to the second actuating portion and a resonance frequency of the optical fiber cantilever is less than 100 Hz.
12 . The scanning device according to claim 10 , wherein
the sub-vibration system constituted by the second actuating portion and the optical fiber cantilever satisfies a frequency characteristic: in a frequency range (n*F x 0 −200 Hz, n*F x 0 +200 Hz), a quantity of significant peaks on an impedance curve and/or a phase curve is 0, wherein F x 0 is the driving frequency of the second actuating portion, and n is a natural number greater than or equal to 2; or
resonance frequencies of the first actuating portion and the optical fiber cantilever satisfy a frequency characteristic: in a frequency range (n*Fm−20, n*Fm+20), a quantity of significant peaks on an impedance curve or a phase curve is 0, wherein Fm is a resonance frequency of the first actuating portion, and n is a natural number greater than or equal to 2.
13 . The scanning device according to claim 10 , wherein a significant peak of a frequency characteristic curve of the second actuating portion and the optical fiber cantilever does not coincide with a significant peak of a frequency characteristic curve of the first actuating portion and the optical fiber cantilever.
14 . The scanning device according to claim 10 , wherein in a frequency range corresponding to the frequency characteristic curve, there is no significant peak in a frequency range that is different from a driving frequency of the second actuating portion by 500 Hz.
15 . The scanning device according to claim 14 , wherein
a most significant peak in the frequency range corresponding to the frequency characteristic curve satisfies: (Z mx −Z mn )/(Z mx +Z mn )≤5%, wherein Z mx is an impedance or phase maximum value corresponding to the most significant peak, and Z mn is an impedance or phase minimum value corresponding to a peak adjacent to the most significant peak on the impedance curve or the phase curve; or
on the frequency characteristic curve, a frequency difference between adjacent peaks of the driving frequency of the second actuating portion is less than 80 Hz.
16 . The scanning device according to claim 10 , wherein a quantity of resonance peaks in a frequency range (0.9*n*F y , 1.1*n*F y ) is 0, wherein F y is the driving frequency applied to the first actuating portion, and n is a natural number greater than or equal to 2.
17 . A method for setting a driving condition of a scanning device according to claim 1 , the method comprising:
determining a natural frequency corresponding to the fast scanning axis in the scanning device;
applying a driving signal to the fast scanning axis based on the determined natural frequency, and determining the frequency that is applied to the fast scanning axis and that has the largest amplitude in the driving signal spectrum or the scanning trajectory response spectrum based on the driving signal;
determining, based on the frequency that is applied to the fast scanning axis and that has the largest amplitude in the driving signal spectrum or the scanning trajectory response spectrum and the quantity of the significant peaks on the frequency characteristic curve, the set frequency range of the driving signal for driving the fast scanning axis; and
using the set frequency range, the frequency that is applied to the fast scanning axis and that has the largest amplitude in the driving signal spectrum or the scanning trajectory response spectrum, and the quantity of the significant peaks on the frequency characteristic curve as driving conditions of the scanning device, to complete driving condition setting.
18 . A scanning display module, comprising at least a scanning device, a light source, and a control circuit, wherein
the scanning device performs raster scanning in an operating state and comprises two scanning axes configured to vibrate in a first direction and a second direction, the two scanning axes have different frequency characteristics, and the frequency characteristics of the two scanning axes satisfy that a quantity of significant peaks on a frequency characteristic curve does not exceed 5 in a set frequency range of [0.6*F x 0 , 1.3*F x 0 ], wherein F x 0 is a frequency that is applied to a fast scanning axis and that has a largest amplitude in a driving signal spectrum or in a scanning trajectory response spectrum; and
under the control of the control circuit, the light source outputs image light, and then the scanning device outputs the image light to implement scanning display.
19 . The scanning display module according to claim 18 , wherein the scanning device comprises at least one of an optical fiber scanner or a MEMS scanning mirror.
20 . A scanning device for performing raster scanning in an operating state, comprising:
two scanning axes configured to vibrate in a first direction and a second direction, the two scanning axes have different frequency characteristics, and the frequency characteristics of the two scanning axes satisfy:
a quantity of significant peaks on a frequency characteristic curve does not exceed a set quantity in a set frequency range,
wherein the scanning device is an optical fiber scanner, the two scanning axes comprise a first actuating portion and a second actuating portion, the scanning device further comprises an optical fiber cantilever, a driving frequency of the first actuating portion is smaller than that of the second actuating portion, the first actuating portion and the second actuating portion drive the optical fiber cantilever to scan along a raster trajectory, and the frequency characteristic curve comprises at least one of an impedance curve and a phase curve,
wherein the driving frequency comprises a frequency having a largest amplitude in a driving signal spectrum or a scanning trajectory response spectrum applied to the first actuating portion or the second actuating portion,
wherein the scanning trajectory response spectrum is a spectrum of a response signal generated, in response to a response to a driving signal on the first or second actuating portion, by a sub-vibration system constituted by the first or second actuating portion and the optical fiber cantilever, and
wherein a frequency characteristic of the sub-vibration system constituted by the first or second actuating portion and the optical fiber cantilever satisfies: a quantity of significant peaks on at least one of an impedance curve or a phase curve does not exceed 5 in a frequency range [0.6*Fx 0 , 1.3*Fx 0 ], wherein Fx 0 is a frequency that is applied to a fast scanning axis and that has a largest amplitude in the driving signal spectrum or in the scanning trajectory response spectrum; and
a frequency difference between resonance frequencies of the second actuating portion and the optical fiber cantilever is greater than 1.2 KHz; or
a frequency difference between resonance frequencies of the second actuating portion and the optical fiber cantilever is less than 5 KHz.