JP2007052218A - Projector having imaging function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector having an imaging function, in which imaging without being affected by illuminating light can be achieved without adding a component such as a polarization conversion element. <P>SOLUTION: The illuminating section 1 is alternately turned on and off to intermittently emit illuminating light. The illuminating light emitted from the illuminating section 1 is separated into P polarized light and S polarized light by a PBS 2. The P polarized light is transmitted through a separation part 2a and made incident on an imaging element 6 whereas the S polarized light is reflected by the separation part 2a and made incident on an LCOS (Liquid Crystal On Silicon) 3. Based on image information, the LCOS 3 modulates and emits the incident S polarized light. In addition to the P polarized component of the illuminating light, imaging light is made incident on the imaging element 6 from outside via a projection lens 5. Imaging by the imaging element 6 when the illuminating section 1 is turned off makes it possible to image only the imaging light made incident from outside via the projection lens 5, without being affected by the illuminating light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector with an imaging function capable of not only projecting an image on a screen but also imaging through a projection optical system.

  2. Description of the Related Art Conventionally, a projector that can not only project an image on a screen but also capture information displayed on the screen is known (see, for example, Patent Document 1). In this projector, a polarization conversion element is provided in the illumination system so that only a specific linearly polarized component is incident on a PBS (polarized beam splitter), and the linearly polarized component is guided to a light valve.

JP 2003-44839 A

  However, the provision of the polarization conversion element has a problem in that the apparatus becomes large and the cost increases. Also, if the polarization conversion element cannot completely convert to a specific polarization component, the component that could not be converted enters the image sensor without being guided to the light valve by the PBS, and the illumination light is overlapped with the imaging light, which adversely affects photography. Effect. In particular, since the projector has a high light source luminance, the influence of such illumination light cannot be ignored.

According to a first aspect of the present invention, there is provided a projector with an imaging function, an illuminating unit that alternately turns on and off and emits illumination light intermittently; and illumination light that includes first polarized light and polarized light having a first polarization direction. A polarization separating element that separates the polarized light into different second polarized light, a light valve that modulates the first polarized light separated by the polarization separating element based on video information, and emits the modulated light; A projection optical system for projecting the emitted modulated light onto the screen, and the second polarized light exiting direction with respect to the polarization separation element, and imaging light enters through the projection optical system and the polarization separation element The image pickup device includes: an image pickup device; and an image pickup device control unit that causes the image pickup device to store an image pickup charge when the illumination unit is turned off.
According to a second aspect of the present invention, in the projector with an imaging function according to the first aspect, when the imaging charge is accumulated by the imaging device, the light valve is emitted from the light valve without changing the polarization direction of the incident polarized light. Is provided with light valve control means for controlling.
According to a third aspect of the present invention, there is provided a projector with an imaging function, wherein the illumination unit can selectively emit any one of a plurality of color lights as illumination light, and the illumination light emitted from the illumination unit is converted into the first polarized light. A polarization separation element that separates the light and the second polarization light having a polarization direction different from that of the first polarization light; and the first polarization light separated by the polarization separation element is modulated based on video information, and the modulated light is A light valve that emits light, a projection optical system that projects the modulated light emitted from the light valve onto the screen, and a projection optical system and polarization that are disposed in the light emission direction of the second polarized light with respect to the polarization separation element The imaging light is incident through the separation element, and a plurality of color lights are sequentially emitted in time-division by the imaging element in which each pixel is provided with a transmission filter corresponding to each color light and the illumination unit, and at the timing of emission of each color light. Control means for performing image pickup by the image pickup device, and image generation means for generating a color image using an output signal of a pixel provided with a transmission filter that does not support color light at the time of image pickup And

  According to the present invention, it is possible to provide a projector having an imaging function without adding components such as a polarization conversion element.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a projector with an imaging function according to the present invention. The projector includes an illumination unit 1 that generates illumination light, a drive circuit 10 for the illumination unit 1, a polarization beam splitter (hereinafter referred to as PBS) 2, an LCOS3 that is a kind of a reflective liquid crystal light valve, and a drive circuit 15 for LCOS3. A projection lens 5, a CCD type image pickup device 6, a drive circuit 16 for the image pickup device 6, an image processing circuit 13, and a CPU 14 for controlling the entire projector. In the present embodiment, a CCD is used as the image pickup device 6, but a CMOS type or other image pickup device may be used.

  The illumination unit 1 includes a high-intensity LED 11 that is a light source, and a condenser lens 12 that makes light from the LED 11 substantially parallel light. The LED 11 is provided with LEDs of three colors of R, G, and B in one package, and white light can be obtained by simultaneously lighting these LEDs. It is also possible to emit light by switching R, G, and B LEDs. Non-polarized white light emitted from the illumination unit 1 enters the PBS 2.

  The PBS 2 is provided with a separation surface 2a on which a polarization separation film is formed. The light incident on the PBS 2 is S-polarized light whose polarization direction is the y-axis direction on the separation surface 2a, and the polarization direction is orthogonal to the y-axis. Separated into P-polarized light. The polarization separation film is configured to transmit P-polarized light and reflect S-polarized light, and the S-polarized light reflected by the separation surface 2a is emitted from the PBS 2 and enters the LCOS 3.

  The LCOS 3 is a liquid crystal panel (light valve) in which liquid crystal is interposed between a silicon substrate and a glass substrate. On the silicon substrate, switching elements such as TFTs and electrodes are provided corresponding to each sub-pixel of the pixel. An aluminum layer that reflects light is formed on the outermost surface of the silicon substrate. The liquid crystal layer interposed between the transparent electrode and the glass substrate can be electrically driven to display an image. Here, a case where a color display LCOS including a color filter is used will be described.

  The drive circuit 15 controls the application of voltage to the electrodes provided in each pixel of the LCOS 3 based on the level of the video signal input from the CPU 14. When a voltage is applied to each electrode of the LCOS 3 according to the level of the video signal, the alignment of the liquid crystal molecules in the liquid crystal layer changes, and the liquid crystal layer serves as a phase plate. As a result, a video pattern corresponding to the voltage application state is formed on the LCOS 3 and spatial light modulation is performed.

  For example, S (P) polarized light incident from the glass substrate side of LCOS 3 is reflected by the reflecting surface (aluminum layer) on the silicon substrate side and is emitted from the glass substrate again, but S (P) incident on the white pixel portion during that time. The polarization direction is modulated (polarization conversion) by rotating the polarization direction by 90 degrees to P (S) polarization. On the other hand, the S (P) polarized light incident on the black pixel portion does not change its polarization state and is emitted as S (P) polarized light.

  In the projector according to the present embodiment, the lighting circuit 1 is controlled to be turned on and off by the drive circuit 10 so that the lighting unit 1 is turned on and off intermittently, and the projected image is displayed on the screen when the lighting unit is turned on. 6 is performed. FIG. 2 is a timing chart showing the timing when the lighting unit 1 is turned on / off (on / off) and the timing when the imaging device (CCD) 6 is turned on / off.

  At time t1 to t2, imaging by the image sensor 6 is turned off and the illumination unit 1 is turned on (lighted) to perform a projection operation. Conversely, at time t2 to t3, the illumination unit 1 is turned off and the imaging operation by the image sensor 6 is performed. (Imaging charge accumulation operation and accumulated charge readout operation) are performed. Note that the read operation of the accumulated charge of the image sensor 6 may be performed while the illumination unit 1 is turned on. In this case, an imaging charge accumulation operation is performed as an imaging operation when the illumination unit 1 is turned off.

  Similarly, the lighting unit 1 is turned on at times t3 to t4 and t5 to t6, and the lighting unit 1 is turned off and the imaging device 6 is turned on at t4 to t5. Such lighting and imaging are repeated alternately. Note that the formation of the video pattern by the LCOS 3 may be performed only when the illumination unit 1 is turned on, or may be always performed regardless of whether the lighting unit 1 is turned on or off. Here, the lighting unit 1 is turned on and off (for example, a frequency with lighting and turning off at times t1 to t3 as one cycle), for example, 50 Hz (= 20 ms cycle) so as not to cause a flickering feeling in the projected image. Preferably, it is 60 Hz or more.

  3A is a diagram for explaining an optical path at the time of image projection, and FIG. 3B is a diagram for explaining an optical path at the time of imaging. For example, at the time of projection at times t1 to t2 in FIG. 2, the illumination unit 1 in FIG. 1 is turned on, and the non-polarized white light W is emitted from the illumination unit 1 to the PBS 2 as shown in FIG. . When the white light W is incident on the separation surface 2a of the PBS 2, S-polarized light is reflected by the separation surface 2a, and P-polarized light is transmitted through the separation surface 2a.

  S-polarized light reflected by the separation surface 2 a is emitted from the PBS 2 and enters the LCOS 3. The S-polarized light incident on the LCOS 3 is emitted as P-polarized light when the incident pixel is a white pixel displaying a white image and the polarization direction is rotated while reciprocating the liquid crystal layer of the LCOS 3. The modulated light (P-polarized light) emitted from the LCOS 3 passes through the separation surface 2a of the PBS 2 and is projected on the screen by the projection lens 5 shown in FIG. Conversely, if the pixel on which the S-polarized light is incident is a black pixel, the polarization direction is not rotated, and the S-polarized light is emitted from the LCOS 3. The S-polarized light is reflected by the separation surface 2a and returns to the illumination unit 1.

  On the other hand, the P-polarized light transmitted through the separation surface 2 a of the PBS 2 is emitted from the PBS 2 and enters the image sensor 6. At the timing shown in FIG. 3A (for example, timing from time t1 to time t2 in FIG. 2), imaging by the imaging device 6 is turned off, so that part of the illumination light (P-polarized light) is applied to the imaging device 6. Even if it enters, there is no influence on a captured image.

  FIG. 3B shows an optical path at time t2 to t3 in FIG. 2, for example, when imaging by the image sensor 6 is performed. At this time, since the illumination unit 1 is in an off (light-off) state, illumination light is not incident on the PBS 2. On the other hand, the light L incident on the PBS 2 via the projection lens 5 is in a non-polarized state, and the P-polarized component of the light L is transmitted through the separation surface 2a of the PBS 2 and incident on the LCOS 3. At this time, if the pixel to which the P-polarized light of LCOS 3 is incident is a white pixel, the P-polarized light is converted into S-polarized light and emitted, reflected by the separation surface 2a, and returned to the illumination unit 1. On the contrary, when the pixel of the incident part is a black pixel, the P-polarized light incident on the LCOS 3 from the PBS 2 is emitted as the P-polarized light, so that the P-polarized light is transmitted through the separation surface 2a and projected onto the screen.

  On the other hand, the S-polarized component of the light L is reflected by the separation surface 2 a of the PBS 2 and enters the image sensor 6, and an image by the S-polarized component is captured by the image sensor 6. The imaging signal output from the imaging device 6 is input to the image processing circuit 13, where a series of image processing is performed. In this case, as shown in FIG. 2, the image pickup device 6 may intermittently pick up images, or after the image pickup device 6 is continuously picked up, only the image pickup data at the illumination light extinguishing timing is used. Anyway.

  In this way, by controlling turning on / off of the illumination unit 1 and on / off of imaging by the imaging device 6, the state of the background other than the projection image, for example, a display described on the screen so as to be superimposed on the projection image, etc. Can be imaged using the image sensor 6. Further, a character or the like is drawn on the screen with the light of the pointer, the trajectory is imaged by the image sensor 6, and the trajectory of the pointer light is projected and displayed using the LCOS 3 by using the image data by the image processing circuit 13 and the CPU 14. You can also use it like this.

  The operation shown in FIG. 2 applies not only to the color display using the LCOS 3 provided with the color filter and the white light as described above, but also to the case where the monochromatic light and the monochrome type LCOS are used. be able to. By the way, when performing color display using a monochrome type LCOS, there is color display by field sequential driving in which illumination is sequentially performed with R, G, and B light.

  FIG. 4 is a timing chart for explaining field sequential driving. In this case, the R, G, and B three-color LEDs provided in the LED 11 are made to emit light in time division order. That is, the R light LED is turned on at times t1 to t2, the G light LED is turned on at times t2 to t3, the B light LED is turned on at times t3 to t4, and all LEDs are turned on at times t4 to t5. Turns off. From time t4 to time t5 when the LED is turned off, imaging by the imaging element 6 is performed. Thereafter, the R light LED is turned on again at times t5 to t6. After the time t5, the series of operations described above are repeated. Here, in the case of the field sequential drive, it is preferable that each color is switched at a speed three times as high as that in the case of the white light described above, and the switching period is 50 Hz to 60 Hz or more in the RGB three-color set.

  As for the display of LCOS3, at times t1 to t2 when the R light is emitted, a video pattern relating to R data of color display is formed on each LCOS3, and a projected image relating to R is projected on the screen. Similarly, at times t2 to t3 when the G light is emitted, an image pattern relating to data is formed on the LCOS 3 in the G color and a projected image relating to the G color is projected, and at times t3 to t4 when the B light is emitted. A video pattern related to data is formed on the LCOS 3 and a projected image related to the B color is projected. Instead of using a monochrome type LCOS as the LCOS 3, a color display LCOS provided with R, G, B color filters may be used.

  As described above, when the projected images of R, G, and B colors are sequentially projected on the screen in a short time, a color display image can be observed by the afterimage effect. In addition, during time t1 to t4, as shown in FIG. 3A, illumination light (P-polarized light) transmitted through the separation surface 2a is incident on the image sensor 6, but at time t1 to t4, imaging by the image sensor 6 is performed. Is not performed, so there is no influence on imaging.

  From time t4 to t5, the illumination unit 1 is turned off, and all the pixels of the LCOS 3 are brought into a black display state. That is, the polarized light incident on the LCOS 3 is emitted from the LOCS 3 without changing its polarization direction, and the imaging operation by the imaging device 6 is performed. At this time, since the illumination unit 1 is in an extinguished state, imaging can be performed without being affected by illumination light. Furthermore, since the entire LCOS 3 is displayed in black, the external light component (P-polarized light) is reflected as it is by the LCOS 3 and passes through the separation surface 2a, so that there is almost no possibility of entering the image sensor 6. The image processing circuit 13 performs a photometric operation when the light is turned off, and determines the electronic shutter speed of the image sensor 6 or the amplification degree of the signal output from the image sensor 6. The photometric operation may be performed by separately providing a photometric element or may be performed based on a signal output from the image sensor 6.

  Of course, the entire LCOS 3 may be displayed in white instead of black. In that case, as shown in FIG. 3B, the external light component (P-polarized light) transmitted through the separation surface 2a and incident on the LCOS 3 is transmitted by the LCOS 3. Modulated to S-polarized light (polarized light conversion), reflected by the separation surface 2a, and guided toward the illumination unit 1. If this s-polarized light is internally reflected by the illuminating unit 1 to change the polarization direction and come out in the direction of the PBS 2 again, there is a possibility that the S-polarized light enters the image sensor 6. For this reason, it is preferable that the entire LCOS 3 is displayed in black during imaging by the imaging element 6.

  As described above, by alternately repeating the image projecting operation from time t1 to t4 and the image capturing operation from time t4 to t5, image projection and image capturing can be performed simultaneously. In the above description, the imaging device 6 performs imaging only at the timing when the illumination unit 1 is turned off. However, continuous imaging is performed and image processing is performed using only imaging data at the timing when the lighting unit 1 is turned off. Anyway. The photometric operation may be performed by separately providing a photometric element or may be performed based on a signal output from the image sensor 6. In addition, during the time when the R light LED, the G light LED, and the B light LED are turned on at the timings t1 to t2, t2 to t3, and t3 to t4 in FIG. A configuration in which an imaging operation by the imaging element 6 is performed may be employed.

  FIG. 5 is a timing chart showing another example of color display by field sequential driving. In the example illustrated in FIG. 4, when the R light LED, the G light LED, and the B light LED of the lighting unit 1 are sequentially turned on, a light-off time (time t4 to t5 in FIG. 4) is provided for each cycle. In the example shown in (2), the light is turned on repeatedly without turning off the light. In FIG. 5, the intervals are displayed for each cycle so as to be easily understood.

  Further, regarding the operation of the image pickup device 6, the image pickup is performed continuously instead of intermittently as shown in FIG. The image sensor 6 has a pixel with an R filter that transmits R light, a pixel with a G filter that transmits G light, and a pixel with a B filter that transmits B light in a predetermined pattern. Is formed. The image processing circuit 13 generates R color data based on the output signal of the pixel provided with the R filter, generates G color data based on the output signal of the pixel provided with the G filter, and provides the B filter. B color data is generated based on the output signal of the obtained pixel.

  And about the imaging data obtained in the time t1-t2 when R light LED is lighted, only G color data and B color data of imaging data are used. From time t1 to t2, not only the external light component (S-polarized light) incident through the projection lens 5 but also the illumination light transmitted through the separation surface 2a (P-polarized component of R light) is incident on the image sensor 6. ing. In the pixel provided with the G filter and the B filter, this illumination light is cut by each filter. However, in the pixel provided with the R filter, the P-polarized component of the R light passes through the filter. For this reason, the influence of illumination light appears greatly in the R color data, and as described above, the R color data is not used as imaging data.

  Further, among the R color data, G color data and B color data obtained by imaging at the time t2 to t3 when the G light LED is turned on, only the R color data and the B color data are used without using the G color data. Is used. Similarly, the B color data obtained by imaging at the timings t3 to t4 when the B light LED is lit are not used, but only the R color data and the G color data are used. Then, if the data of each color obtained is averaged for each color, data of R, G, B3 colors can be obtained. Or it is good also as R, G, B data using G, B data at the time of R light emission, and R data at the time of G light emission. In the driving example shown in FIG. 5, since the illumination is not turned off, flickering of the projected image can be avoided.

  As described above, in the projector according to the present embodiment, when the illumination unit 1 is turned off, the drive circuit 16 controls the imaging unit 6 to perform imaging so that components such as a polarization conversion element can be provided as in the past. An imaging function can be added without adding, and a small projector with an imaging function can be provided at low cost.

  Further, in a conventional projector with an imaging function, the CCD sensitivity may be adjusted (gain up) according to the brightness of the imaging target. In such a case, even a small amount of illumination light is mixed in the light incident on the CCD. If this is done, the effect will be noticeable when the gain is increased. However, in this embodiment, since the illumination light is turned off or the illumination light is cut by the CCD color filter, the influence of the illumination light is eliminated, and an appropriate gain increase according to the external brightness is possible. It becomes.

  In addition, the above description is an example to the last, and this invention is not limited to the said embodiment at all unless the characteristic of this invention is impaired. For example, in FIG. 1, the image sensor 6 is arranged to face the illumination unit 1, but the arrangement of the image sensor 6 and the LCOS 3 may be changed so that the LCOS 3 faces the illumination unit 1.

It is a figure which shows schematic structure of the projector with an imaging | photography function by this invention. 4 is a timing chart showing the lighting timing of the illumination unit 1 and the imaging timing by the imaging device (CCD) 6. (A) is a figure explaining the optical path at the time of image projection, (b) is a figure explaining the optical path at the time of imaging. It is a timing chart which shows the 1st example of the color display by a field sequential drive. It is a timing chart which shows the 2nd example of the color display by a field sequential drive.

Explanation of symbols

1: Illumination unit 2: Polarizing beam splitter 3: LCOS 5: Projection lens 6: Image sensor 10, 15, 16: Drive circuit 13: Image processing circuit 14: CPU

Claims (3)

Illumination means for intermittently emitting illumination light by alternately turning on and off, and
A polarization separation element that separates the illumination light into first polarized light and second polarized light having a polarization direction different from that of the first polarized light;
A light valve that modulates the first polarized light separated by the polarization separation element based on video information and emits the modulated light;
A projection optical system that projects the modulated light emitted from the light valve onto a screen;
An imaging element that is disposed in an emission direction of the second polarized light with respect to the polarization separation element, and in which imaging light is incident through the projection optical system and the polarization separation element;
A projector with an imaging function, comprising: an imaging element control unit that causes an imaging charge accumulation operation by the imaging element when the illumination unit is turned off. The projector with an imaging function according to claim 1,
An imaging function comprising: a light valve control means for controlling the light valve so as to emit light from the light valve without changing a polarization direction of incident polarized light when the imaging charge is accumulated by the imaging device With projector. Illuminating means capable of selectively emitting any one of a plurality of color lights as illumination light;
A polarization separation element that separates the illumination light emitted from the illumination unit into first polarized light and second polarized light having a polarization direction different from the first polarized light;
A light valve that modulates the first polarized light separated by the polarization separation element based on video information and emits the modulated light;
A projection optical system that projects the modulated light emitted from the light valve onto a screen;
An imaging light is disposed through the projection optical system and the polarization separation element, and a transmission filter corresponding to each color light is arranged in the emission direction of the second polarized light with respect to the polarization separation element. An image sensor provided in the pixel;
Control means for emitting the plurality of color lights in order by the illumination means in a time-sharing manner, and performing imaging by the imaging element at the emission timing of each color light;
A projector with an imaging function, comprising: an image generation unit configured to generate a color image using an output signal of the pixel provided with the transmission filter that does not support color light at the time of imaging.

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