JP2008089837A - Image projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which can precisely detect the intensity of a light flux emitted from a light source and correctly measure the intensity based thereon. <P>SOLUTION: This projector includes: a light shielding plate to freely move back and fourth to block the path of the light flux from the light source 2, a drive mechanism 93 to drive this shielding plate, a dimmer to adjust the light volume of the light flux from the light source 2, and a light sensor 92 provided on the surface of the light shielding plate facing the light source 2 to detect the intensity of the light flux from the light source 2 when adjusting the light volume. The projector controller unit 10 has an output light intensity acquisition means 14 to acquire the intensity of the light flux detected by the light sensor 92, and a drive mechanism controller 15 to control the drive mechanism based on the acquired light intensity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector.

Conventionally, a light source device, a light modulation device that modulates a light beam emitted from the light source device according to input image information to form an optical image, and an optical image formed by the light modulation device are enlarged and projected There is known a projector including a projection optical device, and a control device that controls the light source device and the light modulation device. Such a projector is widely used for home theater use, presentation use in conferences, and the like. .
By the way, such a projector may include a light modulation device and optical parts and the like may deteriorate due to long-term use. The deterioration of the optical parts and the like leads to deterioration of the image quality of the projected image. It is visually recognized by the observer as color change and partial color unevenness.

  Therefore, in a projector having an RGB three-color LED light source and a light modulation device provided for each color LED light source, a photoelectric conversion element is provided close to the outer peripheral edge of the display area of the light modulation device, and incident from the LED light source There has been proposed a technique for controlling the amount of light emitted from a light source while measuring the amount of light of a light beam with a light detection element (see, for example, Patent Document 1).

JP 2004-317800 A

  However, in the technique described in Patent Document 1, since the light detection element must be provided outside the display area so as not to interfere with the optical image formed by the light modulation device, the luminance of light in the original display area is accurately set. There is a problem that it cannot be detected. In particular, since the technology described in Patent Document 1 includes a light detection element disposed in a light modulation device that is distant from the light source device, it accurately detects light intensity such as luminance and illuminance of a light beam emitted from the light source. There is a problem that can not be.

  An object of the present invention is to provide a projector capable of detecting the light intensity of a light beam emitted from a light source device with high accuracy and accurately measuring the light intensity based on the detected light intensity.

The projector according to the present invention is
A light source device, a light modulation device that modulates a light beam emitted from the light source device according to input image information to form an optical image, and a projection that magnifies and projects the optical image formed by the light modulation device A projector comprising: an optical device; and a control device that controls a device body including the light source device and the light modulation device,
A light-shielding plate provided so as to be able to advance and retreat so as to block the optical path of the light beam emitted from the light source device, and a drive mechanism for driving the light-shielding plate, and adjusting the light amount of the light beam emitted from the light source device. With an optical device,
When adjusting the amount of light, a light detection element that detects the light intensity of the light beam emitted from the light source device is provided on the surface of the light shielding plate that faces the light source device.
The controller is
Output light intensity acquisition means for acquiring the light intensity of the light beam detected by the light detection element;
Drive mechanism control means for controlling the drive mechanism based on the acquired light intensity is provided.

Here, for the light intensity, for example, various values indicating brightness such as luminance and illuminance can be adopted.
According to the present invention, since the light detection element is provided on the light shielding plate of the light control device, the light shielding plate moves forward and backward so as to block the optical path of the light beam emitted from the light source device when controlling the amount of light by the light control device. Therefore, the light intensity of the light beam emitted from the light source device can be measured with high accuracy according to the advance / retreat position of the light shielding plate. Therefore, by measuring the light intensity of the light beam emitted from the light source device according to the advance / retreat position in this way, the output light intensity acquisition means of the control device acquires the light intensity detected by the light detection element, and the light source The drive control of the light control device can be appropriately performed according to the light intensity of the light beam emitted from the device. As a result, for example, when the luminance, illuminance, etc. of the light beam emitted from the light source device is reduced, the light amount control amount by the light shielding plate of the light control device is reduced. By increasing the amount of light control by the light source, a light beam having a stable light intensity can be emitted from the light source device.

In the present invention, the light control device is pivotally supported at one end, is opposed to the optical path of the light beam when fully opened, and closes the optical path of the light beam by rotation, and the pair of light shielding devices A rotating mechanism for rotating the light shielding plate,
It is preferable that the light detection element is provided at the tip of each light shielding plate on the rotating side.
According to this invention, since the light shielding plate of the light control device is configured to block the light beam emitted from the light source device by rotation, the light intensity near the end of the light beam is measured in a state close to the fully opened state. By changing the rotation position, it becomes possible to measure the light intensity at the center of the light beam, and the light intensity emitted from the light source device can be measured over the whole, with higher accuracy. It becomes possible to measure.

In the present invention, input light intensity information acquisition means for acquiring light intensity information included in the input image information, light intensity acquired by the output light intensity acquisition means, and acquisition by the input light intensity information acquisition means Correction amount generation means for generating a correction amount based on the light intensity information that has been made,
It is preferable that the drive mechanism control unit controls the drive mechanism based on the correction amount generated by the correction amount generation unit.
According to the present invention, the light intensity information included in the input image information is acquired by the input light intensity information acquisition means, and the light control device is controlled based on this and the light intensity measured by the light detection element. Therefore, an appropriate light control device can be controlled in accordance with the input image information, and an image with a large contrast change such as a moving image can be displayed more clearly.

In the present invention, it comprises a light source device driving means for driving the light source device,
The control device preferably includes light source device drive control means for performing drive control of the light source device based on the correction amount generated by the correction amount generation means.
According to this invention, the light source device drive control means performs the drive control of the light source device based on the correction amount generated by the correction amount generation means, thereby controlling the drive of the light source device in addition to the control of the light control device. Therefore, the amount of light emitted from the light source device can be changed more greatly.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1] Overall Configuration FIG. 1 shows an optical system of a projector 1 according to an embodiment of the present invention. The projector 1 modulates a light beam emitted from a light source device in accordance with image information to produce a color image (optical). Image), and this color image is enlarged and projected onto the screen Sc.
The projector 1 includes a light source device 2, a uniform illumination optical device 3, a color separation optical device 4, a relay optical device 5, an optical device 6, a color synthesis optical device 7, a projection optical device 8, and a light control device 9. Is done.
The light source device 2 includes a light source lamp 21 and a parabolic reflector 22 each formed of a discharge arc tube, and a radial light beam emitted from the light source lamp 21 is reflected and collimated by the parabolic reflector 22 and emitted to the uniform illumination optical device 3. Is done.

The uniform illumination optical device 3 is an optical system that divides the light beam emitted from the light source device 2 into a plurality of partial light beams and illuminates an image forming region of a liquid crystal panel, which will be described later, substantially uniformly. The first lens array 31, a second lens array 32, a polarization conversion element 33, and a superimposing lens 34.
The first lens array 31 has a configuration in which first small lenses having a substantially rectangular outline when viewed from the incident optical axis direction are arranged in a matrix in a plane substantially orthogonal to the incident optical axis. . Each first small lens splits the light beam emitted from the light source device 2 into a plurality of partial light beams.
The second lens array 32 has substantially the same configuration as the first lens array 31, and has a configuration in which the second small lenses are arranged in a matrix. The second lens array 32 has a function of forming, together with the superimposing lens 34, a light source image of each first small lens of the first lens array 31 on a liquid crystal panel described later.

The polarization conversion element 33 is disposed between the second lens array 32 and the superimposing lens 34, and converts light from the second lens array 32 into substantially one type of polarized light.
Specifically, each partial light converted into approximately one type of polarized light by the polarization conversion element 33 is finally substantially superimposed on a liquid crystal panel (to be described later) by the superimposing lens 34. In the projector 1 using a liquid crystal panel of a type that modulates polarized light, only one type of polarized light can be used, and therefore approximately half of the light from the light source device 2 that emits randomly polarized light cannot be used. For this reason, by using the polarization conversion element 33, the light emitted from the light source device 2 is converted into approximately one type of polarized light, and the use efficiency of light in a liquid crystal panel described later is enhanced.

The color separation optical device 4 includes two dichroic mirrors 41 and 42 and a reflection mirror 43, and a plurality of partial light beams emitted from the uniform illumination optical device 3 by the dichroic mirrors 41 and 42 are converted into red (R), It has a function of separating into three color lights of green (G) and blue (B).
The relay optical device 5 includes an incident side lens 51, a relay lens 53, and reflection mirrors 52 and 54, and the red light separated by the color separation optical device 4 is transferred to the red light liquid crystal panel and the liquid crystal shutter of the optical device 6. Has a guiding function.

At this time, the dichroic mirror 41 of the color separation optical device 4 reflects the blue light component of the light beam emitted from the uniform illumination optical device 3 and transmits the red light component and the green light component. The blue light reflected by the dichroic mirror 41 is reflected by the reflection mirror 43, passes through the field lens 44, and reaches a later-described liquid crystal panel for blue light of the optical device 6.
The field lens 44 converts each partial light beam emitted from the second lens array 32 into a light beam parallel to the central axis (principal light beam). The same applies to the field lens 44 provided on the light beam incident side of the other liquid crystal panel for green light and red light.

Of the red light and green light transmitted through the dichroic mirror 41, the green light is reflected by the dichroic mirror 42, passes through the field lens 44, and reaches a later-described green light liquid crystal panel of the optical device 6.
On the other hand, the red light passes through the dichroic mirror 42, passes through the relay optical device 5, passes through the field lens 44, and reaches a later-described red light liquid crystal panel of the optical device 6.
Note that the relay optical device 5 is used for red light because the optical path length of the red light is longer than the optical path lengths of the other color lights, thereby preventing a reduction in light use efficiency due to light divergence or the like. It is to do. That is, this is to transmit the partial light beam incident on the incident side lens 51 to the field lens 44 as it is.

The optical device 6 is a portion that modulates light according to each color light RGB separated by the color separation optical device 4 to form an optical image, and includes liquid crystal panels 61R, 61G, and 61B as light modulation devices. Composed.
The liquid crystal panels 61R, 61G, and 61B include an image forming area in which a plurality of pixels are arranged in a matrix, and perform gradation display according to image information input in each pixel.
Each of the liquid crystal panels 61R, 61G, and 61B includes a configuration in which liquid crystal is sealed between a pair of transparent substrates, and the liquid crystal is driven by a TFT (Thin Film Transistor) formed on one substrate. Although not shown, an incident side polarizing plate and an exit side polarizing plate are provided on the light emitting side, and the orientation of the liquid crystal is controlled by using the TFT as a switching element, and the light emitted from the emitting side polarizing plate is controlled. The gradation is displayed according to the image information by adjusting the amount.

The color synthesizing optical device 7 synthesizes each color light modulated for each color light emitted from the emission side polarizing plate of the liquid crystal panels 61R, 61G, 61B to form a color image. The color synthesizing optical device 7 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and two dielectric multilayer films are formed on the interface where the right-angle prisms are bonded together. These dielectric multilayer films transmit the color light emitted from the liquid crystal panel 61G and reflect the color lights emitted from the liquid crystal panels 61R and 61B.
The projection optical device 8 is configured as a combined lens in which a plurality of lenses are housed in a cylindrical lens barrel, and a color image formed by the color synthesis optical device 7 is enlarged on the screen Sc by the projection optical device 8. Projected.
A light control device 9 is provided between the first lens array 31 and the second lens array 32 constituting the uniform illumination optical device 3.

[2] Structure of the light control device 9 As shown in FIG. 2, the light control device 9 is provided between the first lens array 31 and the second lens array 32, and emits a light beam emitted from the light source device 2. It has a function to adjust the amount of light.
The light control device 9 includes a pair of light shielding plates 91 whose one ends are pivotally supported, and a light shielding plate driving mechanism that rotates the pair of light shielding plates 91 (not shown in FIG. 2). Configured.
The pair of light shielding plates 91 are disposed outside the optical path emitted from the light source device 2 with the light shielding plate 91 facing each other with the dimming device 9 fully opened, and the end portion on the side far from the light source device 2 is rotated. It is supported by a shaft 91A. Then, as the light amount adjustment of the light control device 9 is performed, the light is rotated about the rotation shaft 91A, the rotation angle θ is increased, the interval between the light shielding plates 91 is gradually narrowed, and the light leaking from there is gradually reduced. To do.

The light shielding plate drive mechanism (not shown) is provided at the upper end of the rotation shaft 91A of each light shielding plate 91, a pair of gears rotating together with the rotation shaft 91A, a drive gear meshing with the pair of gears, And a stepping motor having a drive shaft connected to the drive gear. In this light shielding plate driving mechanism, the stepping motor rotates at a predetermined angle based on a control command from a control device to be described later, and the light shielding plate 91 rotates accordingly, and is held in a predetermined gap to adjust the light amount. Realized.
A light detection element 92 is provided on the rotation tip side of the surface facing the light source device 2 when each light shielding plate 91 is rotated. The light detection element 92 is composed of a photoelectric conversion element such as a photodiode or a CMOS sensor, and outputs an electric signal as a detection value according to the intensity of the received light such as a luminance value.
In addition, as shown in FIG. 3, two light detection elements 92 are provided at approximately one third of the height dimension L of each light shielding plate 91, and the light detection elements 92 are approximately the regions L that are shielded by the light shielding plate 91. It is arranged at a position where it is equally divided by 1 / 3L.

[3] Control Structure of Projector 1 Next, a control structure of the projector 1 having the above-described structure will be described.
FIG. 4 shows a control device 10 that controls the projector 1. The control device 10 performs predetermined image processing on the input image information VIDEO and performs drive control of the liquid crystal panels 61R, 61G, 61B to form optical images on the liquid crystal panels 61R, 61G, 61B. A function of performing the opening degree control of the light shielding plate 91 of the light control device 9 and the applied voltage control of the light source device 2 is provided.
The control device 10 includes an image processing unit 11, a light modulation device drive control unit 12, a driver IC 13, an output light intensity acquisition unit 14, a drive mechanism control unit 15, a mechanism drive circuit 15A, a light source device drive control unit 16, and a light source drive circuit. 16A, input light intensity information acquisition means 17 and correction amount generation means 18 are provided.

The image processing means 11 includes a frame buffer for storing the input image information VIDEO in units of frames, and performs image processing for displaying an appropriate image on the display image data in units of frames stored in the frame buffer. Specifically, a monochrome expansion process, an IP conversion process, a γ correction process, a V-Tγ correction process, and the like are performed.
The light modulation device drive control means 12 is a part that generates a control signal for driving and controlling the liquid crystal panels 61R, 61G, 61B based on the image information processed by the image processing means 11, and is generated for each color light. The drive control signal is output to the driver IC 13.
The driver IC 13 is a part that drives the liquid crystal panels 61R, 61G, and 61B in units of pixels. In the present embodiment, the liquid crystal panels 61R, 61G, and 61B are set according to the RGB color lights. It is provided according to the number.

The output light intensity acquisition unit 14 is a part that acquires a luminance value as light intensity based on the electrical signal from the plurality of light detection elements 92 described above.
The drive mechanism control means 15 is a part that outputs a control command to the mechanism drive circuit 15A and drives and controls the light shielding plate drive mechanism 93 of the light control device 9.
Here, the acquisition of the luminance value by the output light intensity acquisition means 14 is set in accordance with the rotation control position of the light shielding plate 91 by the drive mechanism control means 15 and is emitted from the light source device 2 as shown in FIG. With respect to the width direction dimension W of the illumination area A on the light control device 9 by the light flux, the drive mechanism control means 15 uniformly sets the rotation control position so that the width direction dimension becomes 1/6 W. When the light shielding plate 91 is controlled to rotate to each position, the output light intensity acquisition unit 14 acquires the luminance value from the light detection element 92.

As shown in FIG. 3, the light detection elements 92 provided on the light shielding plate 91 are provided at two places in the height direction, and therefore the output light intensity acquisition unit 14 is provided in the illumination area A of the light source device 2. The luminance value can be obtained at 10 points.
As described above, when the output light intensity acquisition unit 14 acquires the luminance value, the luminance position can be acquired at a plurality of points in the illumination area A of the light source device 2 by changing the rotation position of the light shielding plate 91. Therefore, the light intensity of the light source device 2 can be acquired with higher accuracy.
The light source device drive control means 16 is a part for controlling the voltage applied to the light source device 2 via the light source drive circuit 16A as the light source device drive means, and the light source device according to the correction amount by the correction amount generation means 18 described later. 2 is controlled.

  The input light intensity information acquisition means 17 is a part for acquiring light intensity information, for example, luminance information, chromaticity information, etc. included in the input image information VIDEO. This input light intensity information acquisition means 17 acquires the average luminance of the entire screen from the image data for one frame in the image information VIDEO and acquires it as luminance information, or the image information VIDEO is supplied as digital data such as MPEG2. In this case, it is possible to obtain the luminance information of the image information VIDEO from the information attached to the header or the like.

The correction amount generation unit 18 determines the light amount of the light beam emitted from the light source device 2 based on the luminance value acquired by the output light intensity acquisition unit 14 and the luminance information acquired by the input light intensity information acquisition unit 17. This is a part for generating a correction amount to be corrected.
Specifically, as shown in FIG. 6, the luminance information included in the input image information VIDEO is given as in a graph G1, and the luminance value detected by the light detection element 92 is as in a graph G2. The correction amount generation means 18 generates a difference between the graph G2 and the graph G2 as a correction value. That is, as shown in FIG. 6, when it is preferable that the luminance information acquired from the image information VIDEO output the graph G1 according to the gradation value, the gradation value is k1 on the graph G2. When the luminance value detected by the light detection element 92 at the time is Y1, Y1-Y2 is generated as a correction value so as to be the luminance value Y2 on the graph G1 at the gradation value k1.
Then, the correction amount generation unit 18 outputs the generated correction amount to the light source device drive control unit 16 and the drive mechanism control unit 15.

[4] Action and Effect of Projector 1 Next, the action of the projector 1 having the above-described structure will be described based on the flowchart shown in FIG.
First, when the projector 1 is activated (processing S1), the control device 10 waits until the light emission state of the light source device 2 is stabilized (processing S2).
When the light emission state of the light source device 2 is stabilized, the drive mechanism control means 15 outputs a control command to the mechanism drive circuit 15A to drive the light shield plate drive mechanism 93, and as shown in FIG. Is rotated to the rotation position (step S3).

In this state, the output light intensity acquisition unit 14 acquires a luminance value based on the detection value from the light detection element 92 and acquires the acquired luminance value in a storage area such as a memory (not shown) provided in the control device 10. Record and save (process S4).
The rotation of the light shielding plate 91 by the drive mechanism control means 15 and the acquisition of the luminance value by the output light intensity acquisition means 14 are performed at all the rotation positions shown in FIG. It is determined whether or not the luminance value has been acquired at the rotation position (step S5). If the luminance value has not been completed, step S3 and step S4 are repeated.

When it is determined that the acquisition of all the luminance values has been completed, the correction amount generation means 18 calculates an average luminance value from the obtained luminance values at 10 locations (see FIG. 5), and uses this average luminance value as the current light source. The light intensity of the device 2 is recorded and stored on the memory (processing S6).
Thereafter, when the input of the image information VIDEO is started (processing S7), the input light intensity information acquisition unit 17 acquires the luminance information included in the image information VIDEO input to the image processing unit 11 (processing S8), and corrects it. It outputs to the quantity generation means 18.
The correction amount generation unit 18 generates a correction amount while comparing the previously calculated average luminance value with the acquired luminance information (processing S9), and outputs the correction amount to the drive mechanism control unit 15 and the light source device drive control unit 16. To do.

The light source device drive control unit 16 performs drive control of the light source device 2 based on the correction amount generated by the correction amount generation unit 18 (processing S10), and the drive mechanism control unit 15 adjusts based on the correction amount. The drive control of the optical device 9 is performed (process S11), and the processes S7 to S11 are repeated until the input image information VIDEO is completed.
According to such a projector 1, it is possible to acquire luminance values at a plurality of locations in the illumination area A of the light source device 2 through the processing S1 to processing S6, and by calculating the average luminance value as a representative value, the light source Since the light beam emitted from the device 2 is directly detected and detected at a plurality of locations, the light intensity of the light beam emitted from the light source device 2 can be detected with higher accuracy.
Further, the light control of the light control device 9 and the light emission control of the light source device 2 according to the input image information VIDEO can be performed by the processes S7 to S12, and the calculation of the correction amount is also detected with high accuracy. Therefore, the projector 1 can project a high-quality image corresponding to the input image information VIDEO.

[5] Modifications of Embodiments The present invention is not limited to the above-described embodiments, and includes the following modifications.
In the above-described embodiment, the process of acquiring the light intensity of the light source device 2 at the time of activation is performed. However, the present invention is not limited to this, and for example, when control by the light control device 9 is not performed when displaying an image, It may be executed periodically when the image information is interrupted.
In the above-described embodiment, the liquid crystal panels 61R, 61G, and 61B are employed as the light modulation device. However, the present invention is not limited to this, and the present invention is employed in a light modulation device including a device using a micromirror. Also good.

In the above embodiment, the average of the luminance values detected at a plurality of points is taken as the representative luminance value of the light beam emitted from the light source device 2, but the present invention is not limited to this, and statistics such as median and mode are used. Various values obtained by a general method may be used as representative low luminance values.
In the above-described embodiment, after the input of the image information VIDEO, the light control device 9 and the light source device 2 are simultaneously driven and controlled. However, the present invention is not limited to this, and even if only the light control device 9 is driven and controlled. Good.
In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

1 is a schematic diagram illustrating an optical system of a projector according to an embodiment of the invention. The schematic plan view showing the structure of the light modulation apparatus in the said embodiment. The model elevation view seen from the light source device side showing the structure of the light modulation apparatus in the said embodiment. The block diagram showing the structure of the control apparatus of the projector in the said embodiment. The schematic diagram for demonstrating the detection position by the photon detection element according to the rotation position of the light-shielding plate of the light modulation apparatus in the said embodiment. The graph for demonstrating the correction amount production | generation method by the correction amount production | generation means in the said embodiment. 6 is a flowchart for explaining the operation of the projector in the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Light source apparatus, 8 ... Projection optical apparatus, 9 ... Light control apparatus, 10 ... Control apparatus, 14 ... Output light intensity acquisition means, 15 ... Drive mechanism control means, 16 ... Light source device drive control means, 17 Input light intensity information acquisition means, 18 ... Correction amount generation means, 61R, 61G, 61B ... Liquid crystal panel, 91 ... Shading plate, 91A ... Rotating shaft, 92 ... Photodetection element, 93 ... Shading plate driving mechanism, VIDEO ... Image information

Claims (4)

A light source device, a light modulation device that modulates a light beam emitted from the light source device according to input image information to form an optical image, and a projection that magnifies and projects the optical image formed by the light modulation device A projector comprising: an optical device; and a control device that controls a device body including the light source device and the light modulation device,
A light-shielding plate provided so as to be able to advance and retreat so as to block the optical path of the light beam emitted from the light source device and a drive mechanism for driving the light-shielding plate. With a dimmer to adjust,
When adjusting the amount of light, a light detection element that detects the light intensity of the light beam emitted from the light source device is provided on the surface of the light shielding plate that faces the light source device.
The controller is
Output light intensity acquisition means for acquiring the light intensity of the light beam detected by the light detection element;
A projector comprising drive mechanism control means for controlling the drive mechanism based on the obtained light intensity. The projector according to claim 1, wherein
The light control device is pivotally supported at one end, is opposed to the optical path of the light beam when fully opened, and includes a pair of light shielding plates that block the optical path of the light beam by rotation, and the pair of light shielding plates. A rotating mechanism for rotating,
The projector according to claim 1, wherein the light detection element is provided at a front end of each light shielding plate on the rotating side. In the projector according to claim 1 or 2,
Input light intensity information acquisition means for acquiring light intensity information included in the input image information;
Correction amount generation means for generating a correction amount based on the light intensity acquired by the output light intensity acquisition means and the light intensity information acquired by the input light intensity information acquisition means,
The drive mechanism control means controls the drive mechanism based on the correction amount generated by the correction amount generation means. The projector according to claim 3, wherein
A light source device driving means for driving the light source device,
The controller is
A projector comprising light source device drive control means for controlling drive of the light source device based on the correction amount generated by the correction amount generation means.

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