TW201317626A - Scanning projection device with detection function and detection method thereof - Google Patents

Abstract

A scanning projection device with a detection function and a detection method thereof are disclosed. The scanning projection device comprises at least one light source to produce light beam and a beam deviation device to deviate the light beam to form scanning light beam for projection to form an image area. This invention uses at least one light splitter disposed between the beam deviation device and the image area on the projection path of the scanning light beam to divide, with a predetermined ratio, the scanning light beam into a first and a second partial light beam respectively with more amount and less amount, and to project the second partial light beam to a sensor to form a second image area, such that the sensor is used to detect the second image area to achieve the detection function. This invention further uses at least one modulator to modulate the operation status of the light source and the beam deviation device according to the second image area, avoiding the drawback and inconvenience in prior arts where the periphery of scanning light beam in the image area needs to be cut to form a useful image area, and a scanning line generated by vertical pole initiation out of the useful image area and close to the image area, so as to project the scanning line through the sensor disposed at the pole in each image frame.

Description

Scan projection device with detection function and detection method thereof

The invention relates to a scanning projection device, in particular to a beam deflecting device with a detecting function and a detecting method thereof.

Scanning projection apparatus has been widely used in various devices in the field of optics, for example, designed as a laser scanning unit (LSU) for printers, scanners, etc., or designed as a general term. The laser projector is supplied for a small laser projector or a head-up device (HUD) for automobiles. The scanning projection device utilizes a beam deflecting device for at least one-dimensional vibration to deflect a light beam emitted by at least one light source to form an image region of at least one dimension; wherein the light source may be a laser light source However, it is not limited (it is also possible to use an LED light source), and the at least one-dimensional image area is defined herein as a projected light region formed by a scanning beam formed by the beam deflecting device being projected onto a target region, for example, A beam deflecting device used in a small laser projector or a head-up display for a vehicle uses a two-axis (two-dimensional) scanning function or two single-axis (one-dimensional) scanning functions and each single axis is corrected to be perpendicular to each other. The beam scanner deflects and projects a laser beam onto a target area to form a generally two-dimensional image area. To make a small laser projector, a micro electronic mechanical scanning mirror (MEMS galvanometer) is usually used as a beam scanner.

For convenience of description, the present invention is described below as an example of a scanning projection device applied to a laser projector, but is not limited thereto. A conventional scanning projection device such as US 6,937,372 B2, US 7,972,014 B2, etc., can utilize a beam deflecting device such as a beam scanner having a dual axis scanning function such as a MEMS scanning vibrating device. Mirror) or two beam scanners having a single-axis scanning function and each uniaxially corrected to be perpendicular to each other to deflect a collimated beam at two perpendicular axis intersections to form an image region. An image region can be created to sweep the beam out in a raster pattern or a Lissajous pattern; the image, including the graph or graph, can be used to determine the beam position and the modulated beam power, while on the image area. Based on the received image data to form the desired image pixels.

In order to make a small image projection system, a micromechanical scanning mirror is generally used as a beam deflecting device such as US 6,937,372 B2, US 7,972,014 B2, etc.; electronic driving signals such as alternating current voltage or alternating current The current is applied to the beam scanner to cause the micro-electromechanical scanning galvanometer to produce mechanical vibration; when the beam diverting device is at or near its resonant frequency, the maximum mechanical outcome or large scan can be obtained in a bidirectional motion with a sinusoidal scanning parabolic trajectory. angle. For a raster scanning system, when the vertical scanning motion is controlled by a frequency of 50 Hz or 60 Hz according to the image refresh rate, the horizontal scanning motion is based on the image resolution. At a high frequency, it is usually a sinusoid; for a Lissajous scanning system, both the horizontal and vertical scanning motions are carefully selected sinusoids with a frequency ratio to achieve a stable And repeatable scanning pattern; for the vector type scanning system, if the signal input to the MEMS scanning galvanometer is higher than the linear response frequency of the MEMS scanning galvanometer, the scanning angle of the MEMS scanning galvanometer will be It is not equal to the signal strength input to the MEMS scanning galvanometer and produces a time difference.

In order to accurately project a scanned image, the correct position of the beam after being deflected by the beam scanner must be determined, so that the beam can be modulated to form the desired image pixels according to the received image data; for sinusoidal scanning As long as the scanning frequency and the intersection time point, that is, when the beam passes through the center of the scan span, it is known, based on the mathematical equation of the sinusoidal motion to calculate the beam position relative to the scanning trajectory; The scanner operates at a fixed frequency close to the resonant frequency, and a slight change in the resonant frequency will result in a phase change between the drive signal and the vibration (wobble) motion of the beam scanner. In order to form image pixels at the correct location, the point in time at which the beam is modulated must therefore be corrected. If the phase difference between the time point of the modulated beam and the position of the scanning beam is not properly compensated, the projected image pixels will become displaced and distorted.

Therefore, it is highly desirable to provide a measure to detect whether a beam deflecting device is in a normal operating state. Although the above-mentioned modulation problem, such as the phase difference between the time point of the modulated beam and the position of the scanning beam, some prior art techniques such as US 6,937,372 B2, US 7,972,014 B2, etc., have been proposed to solve the problem; however, The technical means of the prior art mostly use an inductor to be disposed outside the active image field but at least a portion of the sensing area of the sensor is disposed within the vertical extreme of the image area, so that the sensor can be used. Detecting the deflected beam; the beam is switched off at the periphery of the image area to form a practical image area for projecting the image, and is vertically outside the practical image area and close to the image area. Boot to generate a scan line to sweep the sensor once in each image frame. It can be seen that the prior art has at least the following disadvantages:

1. The light beam is switched off at the periphery of the image area to form an active image field for projecting the image, so that the range of the practical image area formed by the light beam is relatively reduced, and the practical image area is wasted. Imaging around.

2. The sensor must be set up at a specific position according to the design, and the beam deflecting device must generate a feedback scan line outside the practical image area and near the vertical end of the image area to be in each image frame (image frame) When the sensor is swept once, it is relatively difficult to assemble and correct the operation, which is not conducive to mass production.

3. The sensing regions of the various sensors have a certain width, that is, the sensing region has a first edge and a second edge separated by a certain width in the width direction (lateral direction), when the feedback scanning line is in each image frame. When the sensor is swept once, the feedback scan line generates a time difference between the electronic pulse signals generated by the first edge and the second edge of the sensor, and the widths of the sensing regions of the various brand sensors are not uniform, so Relatively difficult to assemble and correct the operation, it is not conducive to the design of the modulation circuit, and is not conducive to the selection of various sensors, so that the finished product can not be effectively reduced.

4. The prior art utilizes at least one feedback scan line outside the utility image area and causes the feedback scan line to sweep through the sensor every image frame to establish a detection, calculation and compensation. Mode, but due to the limited area of the sensing area of the sensor, the detection, calculation and compensation functions are relatively limited, for example, the compensation of the phase difference between the time point of the variable beam and the position of the scanning beam, but not The operating state of the light source and the beam deflecting device, such as the intensity of the light beam emitted by the light source or the amplitude (vibration angle), frequency and waveform of the beam deflecting device, may fail to achieve detection, calculation and compensation functions. .

5. The prior art was unable to detect the scanning condition in the active image field in time, so the vector type scanning system could not be detected.

The present invention addresses the shortcomings of the prior art and proposes a technical means for effectively solving the problem.

An object of the present invention is to provide a scanning projection device having a detecting function and a detecting method thereof, the scanning projection device comprising at least one light source for generating a light beam and a beam deflecting device for deflecting the light beam to form a scanning beam And projecting to form an image region; the present invention uses at least one beam splitter to be disposed on the projection path of the scanning beam between the beam deflecting device and the image region, so that the scanning beam is divided into a relatively large proportion by a predetermined ratio. a plurality of and a relatively small amount of the first and second partial beams, and projecting the second partial beam to a sensor to form a second image area, and using the sensor to detect the second image area, In order to achieve the detection function, the present invention further utilizes at least one modulation device to modulate the operating state of the light source and the beam deflecting device according to the second image region, thereby avoiding the disadvantages of the prior art.

In order to make the present invention more clear and detailed, the preferred embodiments and the following drawings are used to describe the structure, method and technical features of the present invention as follows. Referring to FIG. 1 and FIG. 2, the present invention is A schematic view of a first embodiment of a scanning projection device and a plan view thereof. The scanning projection device 1 with detection and compensation function of the present invention mainly comprises: at least one light source 10, a beam deflecting device 20, and at least one beam splitter (BS). And at least one detecting sensor 50; further comprising at least one modulation means 60.

The at least one light source 10 is configured to generate at least one light beam 11 and project to the light beam deflecting device 20; in the embodiment, the at least one light source 10 is only a light source 10 Representative but not intended to limit the invention. The light source 10 can be a laser source but is not limited. The light beam 11 can be visible light, such as composed of a plurality of light beams having red, green, and blue wavelengths; the light beam 11 can also be invisible light, that is, having a wavelength that is invisible to the human eye such as infrared light.

The beam deflecting device 20 is configured to deflect at least one light beam 11 emitted by the light source 10 to form a scanning beam 12, and the scanning beam 12 is projected further outward to form an image region 30 of at least one dimension. . In the embodiment, the beam deflecting device 20 is designed as a MEMS scanning vibrating mirror, but is not used to limit the present invention. The beam deflecting device 20 shown in FIG. 1 has a dual-axis scanning function. Microelectromechanical scanning galvanometer.

The beam splitter (BS) 40 has a spectral characteristic of partially reflecting and partially refracting an incident beam, and is disposed between the beam deflecting device 20 and the image region 30 to project a scanning path of the scanning beam 12. The scanning beam 12 can be divided into a predetermined relatively large amount of the first partial beam 12a and a predetermined relatively small amount of the second partial beam 12b by a predetermined ratio when passing through the beam splitter 40. . In terms of the splitting function of a splitter, the proportion of the partially reflected and partially refracted beams can be selected according to the design requirements, that is, when a relatively large amount of the first partial beam 12a is designed to refract (or reflect) through the splitter At 40 o'clock, the proportion of the beam amount indicating partial reflection and partial refraction of the beam splitter 40 has been set, and another relatively small amount of the second partial beam 12b is in another manner, that is, a reflection mode (or a refractive mode). The beam splitter 40. In this embodiment, the relatively large amount of the first partial beam 12a is projected through the beam splitter 40 in a refracting manner to form a first image region 30a corresponding to the at least one-dimensional image region 30. As shown in FIGS. 1 and 2, the relatively small amount of the second partial beam 12b is projected to a sensor 50 in a reflective manner to further form an image region 30 corresponding to the at least one dimension on the sensor 50 ( a second image area 30b of 30a); in this embodiment, the predetermined relatively small amount of the second partial light beam 12b can be designed as a 5-10 percentage (%) of the beam amount of the scanning beam 12, that is, the The scanning beam 12 can be divided into a relatively small amount of the second partial beam 12b and a relatively large amount of the first partial beam 12a by a ratio of 5%:95% to 10%:90% when passing through the beam splitter 40; Therefore, the first image area 30a projected by the relatively large amount of the first partial beam 12a does not have much difference in light intensity (brightness) compared with the image area 30 formed by the scanning beam 12. And the second image area 30 formed by the relatively small amount of the second partial beam 12b is projected. b has sufficient light intensity for the sensor 50 to detect, and achieves the detection function claimed by the present invention.

The at least one detecting sensor 50 is configured to detect the second image area 30b to achieve the detection function claimed by the present invention; wherein the sensor 50 can be selected from one of the following groups: a charge coupled device A charge-coupled device (CCD), a capacitive photon detector, or a position sensitive device (PSD), but the different types of the above-described inductors 50 are not intended to limit the present invention. The scanning projection device 1 of the present invention is preferably a selective multi-photodetector as the sensor 50. The structure design of the multi-element photodetector or the patterned photon detector can be referred to the reading (pick-up) used in DVD (Digital Video Disc or Digital Versatile Disc). The photodetector is shown in Figure 5 but is not limited.

The invention may further comprise at least one modulation means 60. The at least one modulation device 60 is coupled between the at least one sensor 50, the at least one light source 10, and the beam deflecting device 20 for forming according to the at least one sensor 50. The second image area 30b modulates the operating state of the at least one light source 10 and the beam deflecting device 20. In this embodiment, the modulation device 60 may further include the following units (circuits), but is not intended to limit the present invention: a detection unit 61 is coupled to the sensor 50 for detecting formation. The second image area 30b on the sensor 50 transmits the detected data to a control unit 62; a control unit 62 is coupled to the detecting unit 61 for The data provided by the detecting unit 61 is operated, and the calculated data is separately transmitted to a light source drive unit 63 and/or a bias driving unit 64 according to control needs; a light source driving unit (light) The source drive unit 63 is connected between the light source 10 and the control unit 62 for modulating the operation state of the light source 10 according to the operation result data provided by the control unit 62, such as modulating the light source 10 The intensity of the light beam 11 is emitted; and a deflecting drive unit 64 is coupled between the beam deflecting device 20 and the control unit 62 for use in accordance with the operation result data provided by the control unit 62. Modulation Beam deflection means 20 of the operating state, such as modulating the beam deflection means amplitude (Amplitude) i.e. the angle of vibration, frequency, phase, and the deflection axis of motion, such as a sinusoidal or zigzag motion (sawtooth) 20 of the exercise. Because the design of the modulation device 60 includes a detecting unit 61, a control unit 62, a light source driving unit 63, and a bias driving unit 64, the current electronic technology can be achieved, and the modulation device 60 can be achieved. The circuit design of each unit or the related software design is not a technical feature of the present invention, and thus will not be described herein.

Referring again to FIG. 3, it is a plan view (top view) of a second embodiment of the scanning projection device of the present invention. The difference between the scanning projection device 2 of the second embodiment and the scanning projection device 1 of the first embodiment shown in FIGS. 1 and 2 is that the scanning projection device 2 of the second embodiment is further in the optical splitter (BS). At least one optical element 70 is disposed on the projection path of the second partial beam 12b between the sensor 40 and the inductor 50. The optical element 70 can be a concentrating optical element 70 such as a convex lens as shown in FIG. 3, whereby the relatively small amount of the second partial beam 12b is projected onto the inductor 50 to form the second image area. Before 30b, the concentrating optical element 70 may be first passed to first reduce the area of the projection area of the second partial beam 12b, thereby relatively reducing the area of the inductor 50 or the sensing area required thereof as shown in FIG. The scanning projection device 2 of the second embodiment can be relatively light, thin, and short, so as to achieve the advantageous effects and objects of miniaturization, and relatively reduce the component cost. In addition, the optical component 70 can also be a diffusing optical component 70 such as a concave lens (not shown), whereby the relatively small amount of the second partial beam 12b is projected onto the inductor 50 to form the second component. Before the image area 30b, the diffusing optical element 70 can be used to first diffuse the area of the projection area of the second partial beam 12b, thereby relatively increasing the area of the sensor 50 or the sensing area required (not shown). It is beneficial to improve the precision of detection.

Referring again to FIG. 4, it is a plan view (top view) of a third embodiment of the scanning projection device of the present invention. The difference between the scanning projection device 3 of the third embodiment and the scanning projection device 1 of the first embodiment shown in FIGS. 1 and 2 is that the scanning projection device 3 of the third embodiment further divides the beam splitter (BS). 40 is a recessed surface splitter (BS) 40a designed as shown in FIG. 4, whereby the relatively small amount of the second partial beam 12b can be made while the scanning beam 12 passes through the concave beam splitter 40a. The concentrating function of the concave surface 41 is first condensed and then projected onto the inductor 50, that is, the relatively small amount of the second partial beam 12b is projected onto the inductor 50 to form the second image region 30b. The concave area splitter (BS) 40a can be used to reduce the area of the projection area of the second partial light beam 12b first, so as to relatively reduce the sensing area required by the inductor 50, which is advantageous for the third embodiment. The scanning projection device 3 can be relatively light, thin, and short, achieving the advantageous effect of miniaturization and relatively reducing the component cost.

In addition, the concave-type spectroscope (BS) 40a having the concave surface 41 of the scanning projection device 3 of the third embodiment can be used in combination with the concentrating optical element 70 of the scanning projection device 2 of the second embodiment. The relatively small amount of the second partial beam 12b can be more effectively reduced in the projection area of the second partial beam 12b before being projected onto the inductor 50 to form the second image region 30b, that is, more effectively relative The invention further provides a scanning projection device, which is advantageous in that the scanning projection device of the present invention can be relatively light, thin and short, and the advantages of miniaturization are achieved, and the component cost is relatively reduced. The detecting method includes the following steps: providing a scanning projection device; the scanning projection device includes at least one light source 10 for generating at least one light beam 11; and a beam deflecting device 20 for biasing the at least one light source 10 Ejecting at least one light beam 11 to form a scanning beam 12, the scanning beam 12 is projected further outward to form an image region 30 of at least one dimension; at least one beam splitter (BS) 40 is provided, and the segment is provided The device (BS) 40 is disposed on the projection path of the scanning beam 12 between the beam deflecting device 20 and the image region 30, so that the scanning beam 12 can be divided into a predetermined ratio when passing through the beam splitter 40. Presetting a relatively large amount of the first partial beam 12a and a predetermined relatively small amount of the second partial beam 12b, wherein the relatively larger amount of the first partial beam 12a can be projected outward to form a corresponding one of the at least one dimension The first image area 30a of the image area 30, wherein the relatively small amount of the second partial light beam 12b can be projected onto a sensor 50 to further form an image area 30 corresponding to the at least one dimension on the sensor 50. The second image area 30b; and at least one sensor 50 for detecting the second image area 30b.

The present invention further includes the following steps: providing at least one modulation means 60, the modulation means 60 being coupled between the inductor 50, the light source 10 and the beam deflecting means 20 for The second image area 30b is formed by the sensor 50 to modulate the operating state of the at least one light source 10 and the beam deflecting device 20.

It can be seen from the above that the main technical means of the present invention, that is, the main distinguishing feature from the related prior art such as US 6,937,372 B2, US 7,972,014 B2, etc., is that at least one beam splitter is provided in the beam deflecting device 20 and The scanning path of the scanning beam 12 between the image areas 30 is configured to enable the scanning beam 12 to be divided into a relatively large amount and a relatively small amount of the first and second partial beams 12a, 12b by a predetermined ratio. And the relatively small amount of the second partial beam 12b is projected to a sensor 50 to form a second image area 30b, and the sensor 50 is used to detect the second image area 30b. In addition, at least one modulation device 60 can be reused to modulate the operational state of the light source 10 and the beam deflecting device 20 according to the second image region 30b to avoid the disadvantages of the related prior art.

The above description is only the preferred embodiments of the present invention, and is intended to be illustrative, and not restrictive, and the scope of the Many changes, modifications, and equivalents may be made thereto, all of which fall within the scope of the invention.

1, 2, 3. . . Scan projection device

10. . . light source

11. . . beam

12. . . Scanning beam

12a. . . First part of the beam

12b. . . Second part beam

20. . . Beam deflector

30. . . Image area

30a. . . First image area

30b. . . Second image area

40, 40a. . . Splitter

41. . . Concave surface

50. . . sensor

60. . . Modulation device

61. . . Detection unit

62. . . control unit

63. . . Light source drive unit

64. . . Bias drive unit

1 is a perspective view of a first embodiment of a scanning projection device of the present invention.

Figure 2 is a plan view (top view) of the first embodiment shown in Figure 1.

Figure 3 is a plan view (top view) of a second embodiment of the scanning projection device of the present invention.

Figure 4 is a plan view (top view) showing a third embodiment of the scanning projection device of the present invention.

Fig. 5 is a reference diagram of an embodiment of a sensor (a pickup-up photodetector for DVD) used in the present invention.

1. . . Scan projection device

10. . . light source

11. . . beam

12. . . Scanning beam

12a. . . First part of the beam

12b. . . Second part beam

20. . . Beam deflector

30. . . Image area

30a. . . First image area

30b. . . Second image area

40, 40a. . . Splitter

41. . . Concave surface

50. . . sensor

60. . . Modulation device

61. . . Detection unit

62. . . control unit

63. . . Light source drive unit

64. . . Bias drive unit

Claims (16)

A scanning projection device having a detecting function, comprising: at least one light source for generating at least one light beam; and a beam deflecting device for deflecting at least one light beam emitted by the at least one light source to form a scanning light beam, The scanning beam is projected further outward to form an image region of at least one dimension; at least one beam splitter is disposed on a projection path of the scanning beam between the beam deflecting device and the image region for the scanning The light beam, when passing through the beam splitter, can be divided into a predetermined relatively large amount of the first partial beam and a predetermined relatively small amount of the second partial beam by a predetermined ratio, wherein the relatively large amount of the first partial beam can Projecting outward to form a first image region corresponding to the at least one-dimensional image region, wherein the relatively small amount of the second partial beam can be projected onto an inductor to further form a corresponding to the sensor a second image area of the at least one-dimensional image area; and at least one sensor for detecting the second image area. The scanning projection device of claim 1, wherein the sensor is selected from one of the group consisting of: a charge-coupled device (CCD), a patterned photon detector, and a position. Position sensitive device (PSD). The scanning projection device of claim 1, wherein the predetermined relatively small amount of the second partial beam is 5-10% (%) of the scanning beam, so that the scanning beam passes through the beam splitter. The ratio can be divided into a relatively small amount of the second partial beam and a relatively large amount of the first partial beam in a ratio of 5:95 to 10:90. The scanning projection device of claim 1, wherein the light source is a laser light source. The scanning projection device of claim 1, wherein the light beam comprises one of visible light, invisible light, or a combination thereof. The scanning projection device of claim 5, wherein the beam is composed of a plurality of beams having red, green, and blue wavelengths. The scanning projection device of claim 1, wherein the light beam has a wavelength that is invisible to the human eye. The scanning projection device of claim 1, wherein the beam deflecting device is a microelectromechanical scanning galvanometer. The scanning projection device of claim 1, further comprising at least one optical element disposed on a projection path of the second partial beam between the beam splitter and the inductor for making the relatively small amount The second partial beam can pass through the optical element to reduce or diffuse the projected area of the second partial beam before being projected onto the inductor to form the second image region. The scanning projection device of claim 1, wherein the beam splitter is a concave concave beam splitter for causing the scanning beam to pass through the concave beam splitter. The two-part beam can be projected onto the inductor by the reflection of the concave surface to reduce the projected area of the second partial beam. The scanning projection device of claim 1, further comprising at least one modulation device coupled between the at least one sensor, the at least one light source, and the beam deflecting device for The second image area formed by the at least one sensor is configured to modulate an operation state of the at least one light source and the beam deflecting device. The scanning projection device of claim 11, wherein the modulation device further comprises: a calculation circuit coupled to the inductor, a control circuit coupled to the calculation circuit, and a light source drive circuit coupled to the light source and the A control unit between the control circuits and a beam deflecting device is coupled between the beam deflecting means and the control circuit. The scanning projection device of claim 11, wherein the operating state of the light source that can be modulated by the modulation device comprises an intensity of a light beam emitted by the light source. The scanning projection device of claim 11, wherein the operational state of the beam deflecting device modulated by the modulation device comprises one or a combination of two or more of the following groups: amplitude ( Amplitude) (frequency), frequency, phase, and the way the beam is deflected. A method for detecting a scanning projection device, comprising the steps of: providing a scanning projection device; the scanning projection device comprising at least one light source for generating at least one light beam; and a beam deflecting device for biasing the at least one light source At least one light beam to form a scanning beam, the scanning beam is projected further outward to form an image region of at least one dimension; at least one beam splitter is provided, and the beam splitter is disposed between the beam deflecting device and the image region a scanning path of the scanning beam for dividing the scanning beam into a predetermined relatively large amount of the first partial beam and a predetermined relatively small amount of the second portion by a predetermined ratio when passing through the beam splitter a beam of light, wherein the relatively large amount of the first portion of the beam can be projected outward to form a first image region corresponding to the image region of the at least one dimension, wherein the relatively small amount of the second portion of the beam can be projected onto a sensor Further forming a second image area corresponding to the at least one-dimensional image area on the sensor; and providing at least one sensor for detecting the second image area The detecting method of claim 15, further comprising the step of: providing at least one modulation device, the modulation device being coupled between the inductor, the light source and the beam deflecting device The second image area formed by the sensor is used to modulate an operation state of the at least one light source and the beam deflecting device.