CN107229170B - Projection method based on Lissajous image scanning - Google Patents

Abstract

The invention belongs to the technical field of micro-opto-electro-mechanical systems, and particularly relates to a Lissajous image scanning-based projector and a projection method. The projector comprises a biaxial micro-torsion mirror, a master control system and a laser; the double-shaft micro-torsion mirror comprises a reflecting mirror surface which can do torsion type simple harmonic vibration on an X shaft and a Y shaft which are vertical to each other; the main control system is used for storing image data and mapping the stored image data with the movement position of the reflecting mirror surface, and the laser emits laser according to the pixel color value of the image data and forms a projection image after being reflected by the reflecting mirror surface. The projector does not need larger components such as a lens and the like, has simple structure and low production cost, does not need manual focusing and is simple and convenient to operate. In addition, the invention uses the laser as the light supply source of the projector, has high light source efficiency and can be carried on a relatively small portable device.

Description

Projection method based on Lissajous image scanning

Technical Field

The invention belongs to the technical field of micro-opto-electro-mechanical systems, and particularly relates to a Lissajous image scanning-based projector and a projection method.

Background

The projector is a device capable of projecting an image or video on a curtain or other flat carriers in an enlarged manner, and a digital light processor projector, i.e., a DLP projector, using a digital micro-reflector (DMD) as a core imaging device is more common in the market. The DMD is formed by attaching a plurality of minute mirrors (referred to as micromirrors for short) in a close array of rows and columns to electronic contacts of a silicon wafer, and an image to be projected is converted into a digital signal and stored in the DMD, each micromirror corresponding to one pixel of the generated image. The light beam emitted by the light source is projected on the DMD, the memory in the DMD controls the opening or closing of each micro mirror according to the position and the color of the pixel of the projected image, and the image reflected by the DMD is enlarged by the lens and then is directly projected on a screen to form the projected image. Chinese patent application CN105353576A, published in 2016, 2, 24, provides a miniaturized DLP projector, which can be regarded as a simple optical path system consisting of an LED light source, a DMD chip, and a projection lens set, according to its basic working principle. The projector uses an LED with low light source efficiency as a light supply source, and requires strict and complicated assembly and debugging work in the production and manufacturing process of the projector, which results in high production cost. In addition, the projector needs to be manually focused to clearly display the image content, so the use process is complicated and the operation is inconvenient.

Disclosure of Invention

The invention aims to provide a Lissajous image scanning-based projector and a projection method, and solves the technical problems of low light source efficiency, high production cost and inconvenient use and operation of the traditional DLP projector.

The technical solution of the invention is as follows: a Lissajous image scanning-based projector is characterized in that: the device comprises a biaxial micro-torsion mirror, a master control system and a laser; the double-shaft micro-torsion mirror comprises a reflecting mirror surface which can do torsion type simple harmonic vibration on an X shaft and a Y shaft which are vertical to each other; the main control system is used for storing image data and mapping the stored image data with the movement position of the reflecting mirror surface, and the laser emits laser according to the stored image data and forms a projection image after being reflected by the reflecting mirror surface.

Furthermore, the motion track of the reflecting mirror surface of the biaxial micro torsion mirror around the X axis is

Wherein A is₁Number of pixels of image in horizontal direction, f₁Is the torsional vibration frequency of the mirror surface around the X axis, t is the vibration time,

is the X-axis phase offset;

the motion trail of the reflecting mirror surface of the biaxial micro-torsion mirror around the Y axis is

Wherein A is₂Number of pixels of image in vertical direction, f₂The torsional vibration frequency of the mirror about the Y-axis,

is the Y-axis phase offset.

Further, the master control system comprises a₁×A₂Data buffer for storing image data in matrix

Further, the projector further comprises a feedback system, wherein the feedback system is used for acquiring the light intensity of the projection image and adjusting the light intensity of the laser according to the light intensity of the projection image.

Further, the laser is a red, green and blue laser.

The invention also provides a projection method based on Lissajous image scanning, which is characterized by comprising the following steps of:

1) the RGB three-color data of the image is expressed as A₁×A₂The matrix mode of (2) is stored in the data buffer; wherein A is₁The number of pixels of the image in the horizontal direction, A₂The number of pixels of the image in the vertical direction is shown;

2) controlling the reflector surface of the double-shaft micro-torsion mirror to do torsion type simple harmonic vibration on an X axis and a Y axis which are vertical to each other;

3) mapping the motion position of the reflecting mirror surface of the biaxial micro-torsion mirror with the data storage position in the data buffer area;

4) sequentially reading RGB (red, green and blue) three-color data of the image stored in the data buffer area according to the movement position of the reflector surface along with the time change;

5) and adjusting laser emitted by the laser according to the sequentially read RGB three-color data.

Further, step 3) comprises the steps of:

3.1) discretizing the motion trail of the reflecting mirror surface of the biaxial micro-torsion mirror to obtain a group of motion positions with equal time intervals;

and 3.2) sequentially collecting the movement positions of the reflecting mirror surface according to a fixed time interval, and forming a one-to-one mapping relation between the current movement position and the data storage position in the data buffer area in the step 1).

Further, step 5) comprises the steps of:

5.1) converting the sequentially read RGB three-color data into analog current;

5.2) carrying out laser emission by taking the analog current as the input current of the laser.

The invention has the beneficial effects that: the invention synthesizes Lissajous tracks by controlling the vibration frequency of the reflecting mirror surface of the double-shaft micro-torsion mirror, maps the Lissajous tracks to a data buffer area to obtain image data corresponding to each deflection position, and adjusts the emitted laser of a laser according to the image data so as to generate a projection image. The projector manufactured by adopting the projection mode does not need larger components such as a lens and the like, has simple structure and low production cost, does not need manual focusing and is simple and convenient to operate. In addition, the invention uses the laser as the light supply source of the projector, has high light source efficiency and can be carried on a relatively small portable device.

Drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of the projector based on lissajous image scanning according to the present invention.

Fig. 2 is a schematic diagram of waveforms for driving the mirror surface of a two-axis micro-torsion mirror to perform torsional vibration around the X-axis.

Fig. 3 is a schematic diagram of waveforms for driving the mirror surface of a two-axis micro-torsion mirror to perform torsional vibration around the Y-axis.

Fig. 4 is a lissajous scanned image formed by torsional vibration of the mirror surface of the biaxial micro-torsion mirror in two axial directions of X, Y.

Fig. 5 is a schematic diagram of discretization collection of motion trajectories of a reflecting mirror surface of the biaxial micro-torsion mirror.

FIG. 6 is a diagram illustrating a mapping relationship between the mirror surface movement position of the dual-axis micro-twisted mirror and the data storage position in the data buffer.

Fig. 7 is a schematic diagram of matrix storage of image data in a data buffer.

Wherein the reference numbers are as follows: 1-X axis, 2-laser, 3-Y axis, 4-mirror, 5-biaxial microtrushing mirror, 6-Lissajous scan image, 7-data buffer, 8-X axis time domain trajectory, 9-Y axis time domain trajectory.

Detailed Description

The invention provides a Lissajous image scanning-based projector, and referring to fig. 1, the structure of a preferred embodiment of the Lissajous image scanning-based projector comprises a main control system, a two-axis micro torsion mirror 5 and a laser 2. The double-shaft micro-torsion mirror 5 is provided with a reflecting mirror surface 4, and the reflecting mirror surface 4 can respectively do torsion type simple harmonic vibration by taking an X shaft 1 and a Y shaft 3 which are vertical to each other as rotating shafts. The main control system is used for storing image data and mapping the stored image data with the movement position of the reflecting mirror surface 4, and the laser 2 emits laser according to the stored image data and forms a projection image based on the Lissajous scanning image 6 after being reflected by the reflecting mirror surface 4. When an image is projected, image data enters the master control system, after mapping is formed in the master control system, the current motion position of the reflector 4 is converted into corresponding image data, and display of different pixel color values is achieved through current control of the laser 2. The technical solution of the present embodiment is described in detail below with reference to the accompanying drawings.

Referring to FIG. 2, the movement locus of the reflecting mirror surface around the X axis is

Wherein A is₁The number of pixels in the horizontal direction of the image (1024 in this embodiment), f₁Is the torsional vibration frequency of the mirror surface around the X axis, t is the vibration time,

is the X-axis phase offset;

referring to FIG. 3, the motion trajectory of the mirror surface around the Y-axis is

Wherein A is₂The number of pixels in the vertical direction of the image (768 in this embodiment), f₂The torsional vibration frequency of the mirror about the Y-axis,

is the Y-axis phase offset.

In this embodiment, the two sine waves are respectively used to represent two dimensions of the two-dimensional data, and the two sine waves are superimposed to form a lissajous scanned image with a resolution corresponding to the display screen shown in fig. 4.

Referring to fig. 5, the lissajous motion trajectory of the mirror surface is discretized to obtain a set of motion positions at equal time intervals, i.e., discrete sine wave data (Dx, Dy), where Dx and Dy are motion amplitudes of the mirror surface in the X axis and the Y axis, respectively.

Referring to fig. 6, RGB three-color data of an image to be projected is represented by a₁×A₂Is stored in a data buffer of the master control system. For example, the first row is stored according to the original data arrangement sequence, the reserved address is 0x 000-0 x7FF, and if each row of data is less than 0x800 data, after the last input data is stored, the data is directly jumped to 0x800, and the data starts to wait for receiving and stores the second row of data. This process is repeated until the storage of the entire image data is completed.

Referring to fig. 7, the motion positions of the mirror surface are sequentially collected at fixed time intervals, and the discrete motion positions collected on the X-axis time domain trajectory 8 and the Y-axis time domain trajectory 9 form a one-to-one mapping relationship with the data storage positions in the data buffer 7. In the projection process, reading the image data in each storage position to obtain the pixel value corresponding to the current motion position of the reflector.

Converting sequentially read RGB three-color data into analog current, then using the analog current as input current of a laser to carry out laser emission, and forming two-dimensional projection images with different brightness and color after reflection of the biaxial micro-torsion mirror. In addition, in this embodiment, a feedback system may also be disposed in the projector, and is configured to acquire the intensity of the projected image and perform real-time feedback adjustment on the emission intensity of the laser according to the intensity of the projected image, so as to improve the display effect of the projected image.

Claims (2)

1. A projection method based on Lissajous image scanning is characterized by comprising the following steps:

1) the RGB three-color data of the image is expressed as A₁×A₂The matrix mode of (2) is stored in the data buffer; wherein A is₁The number of pixels of the image in the horizontal direction, A₂The number of pixels of the image in the vertical direction is shown;

2) controlling the reflector surface of the double-shaft micro-torsion mirror to do torsion type simple harmonic vibration on an X axis and a Y axis which are vertical to each other;

3) mapping the motion position of the reflecting mirror surface of the biaxial micro-torsion mirror with the data storage position in the data buffer area;

3.1) discretizing the motion trail of the reflecting mirror surface of the biaxial micro-torsion mirror to obtain a group of motion positions with equal time intervals;

3.2) sequentially collecting the movement positions of the reflecting mirror surface according to a fixed time interval, and forming a one-to-one mapping relation between the current movement position and the data storage position in the data buffer area in the step 1);

4) sequentially reading RGB (red, green and blue) three-color data of the image stored in the data buffer area according to the movement position of the reflector surface along with the time change;

5) and adjusting laser emitted by the laser according to the sequentially read RGB three-color data.

2. The lissajous image scanning-based projection method according to claim 1, wherein step 5) comprises the steps of:

5.1) converting the sequentially read RGB three-color data into analog current;

5.2) carrying out laser emission by taking the analog current as the input current of the laser.

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