JP2010072504A - Image projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanning type image projector having a function of accurately detecting a position pointed on a projected image. <P>SOLUTION: The image projector 10 includes a light receiving part 22 which detects light reflected on the surface of a pointing/reflection means 21 which points an optional position on an enlarged image which is projected on an object such as a screen. An analysis part 23 of the image projector 10 calculates the position of the image pointed the pointing/reflection means 21 on the basis of the timing or the like of a change in the intensity of the light detected by the light receiving part 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image projecting apparatus that displays an image by scanning light emitted from a light source, and in particular, a technique effective when applied to an image projecting apparatus having a function of detecting an indicated position on a projected image. It is about.

  In recent years, there has been an increasing demand for downsizing image projection apparatuses. For example, it is extremely attractive that a mobile phone is equipped with an ultra-compact image projection device and a small screen of the mobile phone can be enlarged and projected so that it can be viewed “anytime and anywhere” by a large number of people regardless of business use or personal use. (See Non-Patent Document 1).

  In addition, the small image projection apparatus can use a mobile phone as an alternative to a personal computer (PC) by using the current high-speed communication technology. That is, it is a so-called thin client system in which computation processing and the like on a PC are left to a remote host computer, and data transferred by high-speed communication is received by a mobile phone and displayed on a small image projector.

  Recently, a series of exhibitions and announcements regarding this type of small image projection device have been made. For example, Microvision Co., Ltd. has shown a mobile phone size ultra-small image projection device and has attracted attention (for example, CES2008).

  There are various types of image projection apparatuses. Among them, the optical scanning type image projection apparatus forms an image by scanning while laser-modulating laser light. In addition, by superimposing laser light of the three primary colors of red, green, and blue, a clear image with a wide color reproduction range can be formed, a semiconductor laser is used as the light source, and a MEMS (Mechanical Electrical Machine System) is used as the beam scanning unit. By using it, it is possible to reduce the size and power consumption.

On the other hand, with respect to a touch panel that performs an input operation by pointing to an arbitrary position on a projected image, an optical pointing position detection method has been proposed in order to detect the pointing position with high accuracy (see Patent Documents 1 and 2). ).
Published by Nikkei BP, "Nikkei Microdevice", (February 2007, pages 23-37) JP 2006-277357 A JP 2007-293915 A

  The inventor of the present invention has studied that the image projection apparatus has a new function by mounting a touch panel-like function for detecting the indicated position of the projected image in the light beam scanning image projection apparatus.

  However, if an image indication position detection function is to be installed in the image projection apparatus, a light source used for the image projection apparatus and a light source for indication position detection are required separately, which complicates the optical system. Further, since the number of parts increases, it is difficult to reduce the size of the apparatus.

  An object of the present invention is to provide an optical scanning image projection apparatus having a function of accurately detecting a designated position on a projection image.

  Another object of the present invention is to realize downsizing of an optical scanning image projection apparatus having a function of accurately detecting a designated position on a projection image.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  An image projection apparatus according to the present invention includes a single or a plurality of light sources, a first optical system that condenses light emitted from the light sources on one axis, and two-dimensionally scans the light collected on the one axis. A projection system for forming projection light, a second optical system for projecting the scanned projection light to the outside and enlarging and projecting it as an image on the surface of the object, and an enlarged projection on the surface of the object An arbitrary position of an image is indicated, an instruction / reflecting unit that reflects the projection light at the indicated position, a light receiving unit that detects reflected light from the instruction / reflecting unit, and detected by the light receiving unit And an analyzing unit that calculates the position instructed by the instruction / reflecting unit based on the reflected light.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  It is possible to realize a small optical scanning type image projection apparatus having a function of accurately detecting the indicated position on the projection image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. Also, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

(Embodiment 1)
FIG. 1 is a configuration diagram of an optical scanning image projection apparatus according to the present embodiment. The image projection apparatus 10 includes a monochromatic light source 11 composed of a red laser, and a condensing lens 12 and a dielectric film filter 13 condense the red laser light emitted from the light source 11 uniaxially in the vicinity of the light source 11. The 1st optical system which consists of these is arrange | positioned. In the present embodiment, the case where the light source 11 is red laser light will be described. However, the color may be any color as long as it is monochromatic laser light, for example, green laser light or blue laser light.

  The condensing lens 12 condenses the red laser light emitted from the light source 11 uniaxially. The dielectric film filter 13 has a property of reflecting about 80% of the red laser light and transmitting about 20%, and is 45 ° with respect to the traveling direction of the red laser light transmitted through the condenser lens 12. Arranged at an angle. Accordingly, a part (about 80%) of the red laser light transmitted through the condenser lens 12 is reflected by the surface of the dielectric film filter 13, and its traveling direction is converted by 90 ° and enters the scanning mirror 14.

  The scanning mirror 14 is composed of, for example, a biaxial drive MEMS element. Moreover, the scanning mirror 14 can also be comprised combining a uniaxial drive MEMS element. The red laser light incident on the scanning mirror 14 is scanned two-dimensionally to form projection light. This scanning speed is, for example, 60 Hz / screen (frame). The projection light scanned by the scanning mirror 14 is emitted to the outside through a lens (second optical system) 15 and then enlarged and projected as an image on the surface of an object such as a screen (not shown).

  On the other hand, the other part (about 20%) of the red laser light that has passed through the condenser lens 12 passes through the dielectric film filter 13 and travels straight and enters the photodetector 16. Further, the control unit 17 connected to the photodetector 16 controls the output of the light source 11 via the laser control unit 19 based on the output signal of the red laser beam detected by the photodetector 16 and the image signal 18. In addition, the operation of the scanning mirror 14 is controlled via the scanning mirror control unit 20.

  An instruction / reflecting unit 21 is provided outside the image projection apparatus 10 for indicating an arbitrary position on the image enlarged and projected on a surface such as a screen. The instruction / reflection means 21 includes a reflector that reflects the projection light at the indicated position. Further, on the surface of the image projection apparatus 10, a light receiving unit 22 including a light receiving element that senses projection light reflected by the surface of the instruction / reflecting unit 21 is provided. Therefore, of the projection light emitted to the outside from the scanning mirror 14, the projection light incident on the instruction / reflection unit 21 is reflected by the surface of the instruction / reflection unit 21 and detected by the light receiving unit 22.

  Inside the image projection apparatus 10, an analysis unit 23 that calculates the position of the image instructed by the instruction / reflecting means 21 is provided. This analyzing unit 23 is an image instructed by the instruction / reflecting means 21 from the timing of intensity change of the projection light detected by the light receiving unit 22 and the timing of scanning of the projection light emitted from the scanning mirror 14 to the outside. The position of is calculated.

  FIG. 2 is a diagram for explaining a method for detecting an indicated position of an image by the instruction / reflecting means 21. The projection light (Lp) emitted from the image projector 10 forms an image 24 by two-dimensional scanning and is enlarged and projected onto the surface of the object. An object on which the image 24 is projected, that is, an object corresponding to a screen does not necessarily have to be a plane. When a certain position on the projected image 24 is indicated by the instruction / reflecting means 21, the projection light (Lp) for projecting the image 24 to the indicated position is reflected by the surface of the instruction / reflecting means 21, and reflected light ( Lr) is received and detected by the light receiving unit 22 of the image projector 10.

  FIG. 3 is a diagram for explaining an example of the structure of the instruction / reflection means 21. The indication / reflecting means 21 includes a light retroreflector 25 made of a corner cube or the like at the tip. Therefore, the projection light incident on the instruction / reflecting means 21 is retroreflected in the direction opposite to the incident direction on the surface of the optical retroreflector 25. Therefore, the reflected light (Lr) from the surface of the light retroreflector 25 can be reliably detected by the light receiving unit 22 of the image projector 10.

  Further, as shown in FIG. 3, an openable / closable cover 26 that covers the light retroreflector 25 is attached to the tip of the instruction / reflecting means 21, and a switch 27 for opening and closing the cover 26 is attached to the other end. It may be attached. In this way, the cover 26 can be opened only when it is desired to indicate the position of the image 24, and the projection light can be reflected by the light retroreflector 25.

  Further, an operation button 28 having a function similar to that of an optical mouse is attached to a part of the instruction / reflecting means 21, and the icon 29 in the image 24 shown in FIG. Various operations (stop, pause, redisplay, fast forward, etc.) can be performed.

  FIG. 4 is a diagram for explaining an example of a scanning path of projection light emitted from the image projection apparatus 10 to the outside. One frame of the image is composed of n scanning lines facing in the same direction. Here, a case where one position on the i-th scanning path is indicated using the indication / reflecting means 21 of FIGS. 2 and 3 will be described. Since the instruction / reflecting unit 21 includes the optical retroreflector 25, the projection light (Lp) emitted from the image projection apparatus 10 and incident on the instruction / reflecting unit 21 is reflected in a direction opposite to the traveling direction thereof. Light is received and detected by the light receiving unit 22 provided in the image projector 10.

  Due to the functions and properties of the light retroreflector 25, the projection light (Lp) and the reflected light (Lr) incident on the light retroreflector 25 do not follow the same optical path and are projected on a screen or the like. Since the image 24 is away from the image projection device 10, the reflected light (Lr) reflected by the light retroreflector 25 has a certain extent. Therefore, by disposing the light receiving unit 22 in the vicinity of the projection light emitting unit of the image projection device 10, the reflected light (Lr) from the light retroreflector 25 is not disturbed by the image 24 projected on the screen or the like. It can be detected by the light receiving unit 22. Therefore, the light receiving unit 22 may be disposed in the vicinity of the lens 15 shown in FIG.

  The scanning path of the projection light is not limited to the method of arranging the lines interrupted in the horizontal direction as shown in FIG. 4, and may be a method of arranging the lines interrupted in the vertical direction, for example. Further, by alternately reversing the directions of adjacent scanning lines, it is possible to form a scanning path that is continuous in a zigzag manner. Further, when the scanning speed is 60 Hz / screen (frame), the time required to project one screen (frame) is 1/60 second. Therefore, there is a point in the projected image 24 and in FIG. The relationship with the leftmost point of the scanning line 1 as the reference point is the same in that it is expressed by a certain time difference.

  FIG. 5 is a timing chart for explaining a method for detecting the indicated position of the image 24 by the indication / reflecting means 21. This figure shows the time for scanning one screen (frame) for one cycle. Moreover, 1 to n of the video electric signals correspond to 1 to n of the scanning lines in FIG.

  As an example, a case where a certain position on the scanning line i is indicated will be described. First, the projection light emitted from the image projection apparatus 10 at the timing a is reflected by the instruction / reflecting unit 21 and reflected by the light receiving unit 22. It is detected as an increase in light intensity. If there is no indication of the position of the image 24 by the indication / reflecting means 21, the reflected light intensity does not increase greatly, and therefore the presence of the indication position is not detected.

Here, if the timing at which the light receiving unit 22 detects the increase in reflected light intensity is b, a time delay occurs by time (ba). As a general scene, this time corresponds to a time when the projection light travels back and forth a distance of 1.5 m when the distance between the image projection apparatus 10 and the instruction / reflection means 21 is 1.5 m. * 2/3 * 10 ⁸ seconds, that is, 10 ns.

  On the other hand, the time required to display one pixel of the image 24 is 1/60 / (800 × 600) in this embodiment because the scanning of the light beam is 60 Hz and the resolution of the projected image is 800 × 600 dots. ) Seconds, ie 35 ns. From the above calculation, it can be seen that the time delay of the light receiving timing is less than the time for projecting one dot at most, so that it is practically not a problem. Thus, in this embodiment, the indication position is detected by synchronizing the timing of the reflected light from the light receiving unit 22 with the projection timing of the image 24 at that time.

  FIG. 6 is a flowchart for explaining a flow from emission of projection light to light reception / detection by the light receiving unit 22.

  First, when an image signal 18 is input to the image projector 10 shown in FIG. 1, red laser light is emitted from the light source 11. The red laser light enters the scanning mirror 14 and is scanned two-dimensionally to form projection light. The projection light scanned by the scanning mirror 14 is emitted to the outside through the lens 15 and then enlarged and projected as an image 24 on a surface such as a screen.

  Here, when there is an image position instruction and projection light reflection by the instruction / reflecting means 21, the reflected light is received by the light receiving unit 22 and detected as an increase in received light intensity. The position of the image 24 instructed by the instructing / reflecting means 21 is detected based on the timing at which the increase in received light intensity is detected and the timing of the image signal 18 output at that time. On the other hand, when the instruction / reflecting means 21 does not indicate the image position and the projection light is not reflected, the light receiving unit 22 does not detect the increase in the received light intensity, so the detection of the light reception timing is not performed. The above flow is repeated. Since the input of the image signal 18 is performed independently of the reception of the reflected light by the light receiving unit 22, the presence or absence of reception of the reflected light does not affect the projection of the image 24.

(Embodiment 2)
FIG. 7 is a configuration diagram of the optical scanning image projection apparatus of the present embodiment. The image projection apparatus 10 according to the first embodiment includes the monochromatic light source 11 composed of a red laser, whereas the image projection apparatus 30 according to the present embodiment includes a light source 31B composed of a blue laser and a green laser. A light source 31R including a light source 31G and a red laser is provided. These three light sources 31R, 31G, and 31B are arranged side by side in one direction.

  In the vicinity of the light source 31B, an optical system including a condenser lens 32 and a dielectric film filter 35 for condensing the blue laser light emitted from the light source 31B uniaxially is disposed. The dielectric film filter 35 has a property of reflecting 90% or more of the blue laser light, and is disposed at an angle of 45 ° with respect to the traveling direction of the blue laser light transmitted through the condenser lens 32. Accordingly, most (90% or more) of the blue laser light transmitted through the condenser lens 32 is reflected by the surface of the dielectric film filter 35 and its traveling direction is converted by 90 °.

  In the vicinity of the light source 31G disposed adjacent to the light source 31B, an optical system including a condensing lens 33 and a dielectric film filter 36 that condenses the green laser light emitted from the light source 31G in one axis is disposed. Yes. The dielectric film filter 36 has a property of transmitting 90% or more of the blue laser light and reflecting 90% or more of the green laser light. The dielectric film filter 36 is disposed on the optical path of the blue laser light reflected by the surface of the dielectric film filter 35, and at an angle of 45 ° with respect to the traveling direction of the green laser light transmitted through the condenser lens 33. Has been placed. Accordingly, most of the blue laser light reflected by the surface of the dielectric filter 35 (90% or more) passes through the dielectric filter 36 and goes straight. Further, most of the green laser light (90% or more) transmitted through the condenser lens 33 is reflected by the surface of the dielectric film filter 36 and its traveling direction is converted by 90 °, and the blue laser beam transmitted through the dielectric film filter 36. Go straight alongside the light.

  In the vicinity of the light source 31R disposed adjacent to the light source 31G, an optical system including a condensing lens 34 and a dielectric film filter 37 that condenses the red laser light emitted from the light source 31R uniaxially is disposed. Yes. The dielectric film filter 37 has a property of transmitting about 80% of the blue laser light and the green laser light and reflecting about 80% of the red laser light. The dielectric film filter 37 is disposed on the optical path of the blue laser light transmitted through the dielectric film filter 36 and the green laser light reflected from the surface of the dielectric film filter 36, and is a red laser transmitted through the condenser lens 34. It arrange | positions at an angle of 45 degrees with respect to the advancing direction of light. Accordingly, about 80% of the blue laser light transmitted through the dielectric film filter 36 and about 80% of the green laser light reflected by the surface of the dielectric film filter 36 pass through the dielectric film filter 37 and go straight. Further, about 80% of the red laser light transmitted through the condenser lens 34 is reflected by the surface of the dielectric film filter 37 and its traveling direction is converted by 90 °, and the blue laser light and the green laser transmitted through the dielectric film filter 37. Go straight alongside the light.

  The blue laser light and green laser light transmitted through the dielectric film filter 37 and the red laser light reflected by the surface of the dielectric film filter 37 are incident on the scanning mirror 38. The scanning mirror 38 is composed of, for example, a biaxial drive MEMS element. Further, the scanning mirror 38 can be configured by combining uniaxially driven MEMS elements. The three colors of laser light incident on the scanning mirror 38 are scanned two-dimensionally to form projection light. The scanning speed here is, for example, 60 Hz / screen (frame). The projection light scanned by the scanning mirror 38 is emitted to the outside through the lens 39, and then enlarged and projected as a full-color image on the surface of an object such as a screen (not shown).

  On the other hand, the blue laser light and the green laser light reflected by the surface of the dielectric film filter 37 and the red laser light transmitted through the dielectric film filter 37 are incident on the photodetector 40. Further, the control unit 41 connected to the light detector 40 is connected to the light sources 31B and 31G via the laser control unit 43 based on the output signals of the three colors of laser light detected by the light detector 40 and the image signal 42. , 31R and the operation of the scanning mirror 38 via the scanning mirror control unit 44.

  Outside the image projection apparatus 30, an instruction / reflecting means 45 is provided for indicating an arbitrary position on the full-color image enlarged and projected on a surface such as a screen. Since the instruction / reflecting means 45 has basically the same configuration as the instruction / reflecting means 21 of the first embodiment, the description thereof will be omitted. On the surface of the image projection apparatus 30, a light receiving unit 46 including a light receiving element that senses the projection light reflected by the instruction / reflecting unit 45 is provided. Accordingly, of the projection light emitted from the scanning mirror 38 to the outside, the projection light incident on the instruction / reflection unit 45 is reflected by the surface of the instruction / reflection unit 45 and detected by the light receiving unit 46.

  Inside the image projection device 30 is provided an analysis unit 47 that calculates the position of the full-color image instructed by the instruction / reflecting means 45. This analysis unit 47 is an image instructed by the instruction / reflecting means 45 from the timing of the intensity change of the projection light detected by the light receiving unit 46 and the timing of the scanning of the projection light emitted from the scanning mirror 38 to the outside. The position of is calculated.

  FIG. 8 is a graph for explaining the operation of the optical scanning image projection apparatus according to the present embodiment. The horizontal axis indicates time, and the vertical axes B, G, and R indicate a light source 31B composed of a blue laser and a green laser. The respective outputs of the light source 31G made up of and the light source 31R made up of a red laser are shown.

  Times a1 and a2 are times for image projection. By adjusting the output of the light sources (31B, 31G, 31R) and superimposing the three colors, any color can be created at any time. The time b1 is a time for detecting the output of the three colors by the photodetector 40. During this time, the light sources (31B, 31G, 31R) are individually operated. By performing such time division, it becomes possible to detect the outputs of a plurality of light sources (31B, 31G, 31R) with a single photodetector 40.

Next, a procedure for projecting a full color image is shown below.
(1) The relationship between the output of the light source (31B, 31G, 31R) and the drive current is obtained by the light detection shown in FIGS.
(2) The control unit 41 converts the two-dimensional image signal into position information and color information.
(3) Based on the relationship obtained in (1), the output of the light sources (31B, 31G, 31R) is adjusted corresponding to the color position information in (2).
(4) According to the position information of (2), the scanning mirror 38 is two-dimensionally scanned in a predetermined step to project a two-dimensional full-color image to the outside.

  Here, it is possible to automatically operate the light detector 40 at regular time intervals, and to automatically operate the light detector 40 at the start of the operation of the image projecting device 30, thereby improving the convenience of the image projecting device 30. Can be improved.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the image projection apparatus of the present invention, the light source is composed of a semiconductor laser element, and the scanning system is composed of a MEMS element, so that the optical scanning image projection apparatus can be miniaturized. Therefore, for example, as shown in FIG. 9, by incorporating the image projection apparatus of the present invention in the cellular phone terminal 50, an ultra-compact optical scanning image projection having a function of accurately detecting the indicated position on the projection image. An apparatus can be realized.

  The present invention can be applied to an optical scanning image projection apparatus having a function of accurately detecting a designated position on a projection image.

1 is a configuration diagram of an optical scanning image projection apparatus according to an embodiment of the present invention. It is a figure explaining the instruction | indication position detection method of the image by an instruction | indication and reflection means. It is a figure explaining an example of the structure of an instruction | indication and reflection means. It is a figure explaining an example of the scanning path | route of the projection light radiate | emitted outside from the image projector. 6 is a timing chart for explaining a method for detecting an indicated position of an image by an instruction / reflecting unit. It is a flowchart explaining the flow from emission of projection light to light reception / detection by a light receiving unit. It is a block diagram of the optical scanning-type image projector which is other embodiment of this invention. It is a graph explaining operation | movement of the optical scanning-type image projector shown in FIG. It is a figure explaining embodiment which incorporated the image projector of this invention in the mobile telephone terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image projector 11 Light source 12 Condensing lens 13 Dielectric film filter 14 Scanning mirror 15 Lens 16 Photo detector 17 Control part 18 Image signal 19 Laser control part 20 Scanning mirror control part 21 Instruction | indication and reflection means 22 Light-receiving part 23 Analysis part 24 Image 25 Optical retroreflector 26 Cover 27 Switch 28 Operation button 29 Icon 30 Image projection device 31B, 31G, 31R Light source 32, 33, 34 Condensing lens 35, 36, 37 Dielectric film filter 38 Scanning mirror 39 Lens 40 Light detection 41 Control unit 42 Image signal 43 Laser control unit 44 Scanning mirror control unit 45 Instruction / reflection means 46 Light receiving unit 47 Analysis unit 50 Mobile phone terminal Lp Projected light Lr Reflected light

Claims (6)

Single or multiple light sources,
A first optical system that condenses light emitted from the light source uniaxially;
A scanning system that forms a projection light by two-dimensionally scanning the light focused on the one axis;
A second optical system that emits the scanned projection light to the outside and enlarges and projects it as an image on the surface of the object;
Indicating / reflecting means for indicating an arbitrary position of the image enlarged and projected on the surface of the object and reflecting the projection light at the indicated position;
A light receiving unit for detecting reflected light from the instruction / reflecting means;
Based on the reflected light detected by the light receiving unit, an analysis unit that calculates the position instructed by the instruction / reflecting unit;
An image projection apparatus comprising:   The indicating / reflecting means is constituted by a system having a light retroreflector, and the projection light at the indicated position is retroreflected by the light retroreflector in a direction opposite to its incident direction. The image projection apparatus according to claim 1.   The image projection apparatus according to claim 2, wherein the light retroreflector is a corner cube.   The image projection apparatus according to claim 1, wherein the light source includes a single light source composed of a monochromatic laser.   2. The image projection apparatus according to claim 1, wherein the light source includes a light source composed of a blue laser, a light source composed of a green laser, and a plurality of light sources composed of a red laser.   The image projection apparatus according to claim 1, wherein the scanning system includes a MEMS element.

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