JP2010243533A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of reducing power consumption by preventing irregular luminance of a projection image and suppressing output from a light source as necessary. <P>SOLUTION: The projector includes: an illumination device that has a first light source 211L and a second light source 211R; an optical modulation device that modulates luminous flux emitted from the illumination device in accordance with image information so as to form an optical image; a projection optical device that projects an optical image formed by the optical modulation device; and a light quantity control means 10 that controls light quantities of the first and second light sources 211L and 211R. The first light source 211L illuminates a first area being a part of an image forming area of the optical modulation device, and the second light source 211R illuminates a second area being a part of the image forming area of the optical modulation device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an illumination device, a light modulation device that modulates a light beam emitted from the illumination device in accordance with image information to form an optical image, and projection optics that projects an optical image formed by the light modulation device. The present invention relates to a projector including the apparatus.

In recent years, in fields such as car external design design, the lighting device and the light beam emitted from the lighting device are modulated in accordance with image information so that the work can be performed while forming an image with an actual size. A projector including a light modulation device that forms an optical image and a projection optical device that projects an optical image formed by the light modulation device is used.
The advantage of using this projector is that a large projected image of 100 inches or more can be easily formed and the product cost as an image display device is low. On the other hand, in a liquid crystal panel projection type projector, There is a problem that unevenness in color, brightness, and contrast is likely to occur on the projection surface.
For this reason, conventionally, there has been proposed a technique that does not cause luminance unevenness in a projected image by controlling an applied voltage applied to a liquid crystal panel (see, for example, Patent Document 1).

In addition, in a technology for forming a large screen image by arranging a plurality of image display devices vertically and horizontally, a technology for eliminating luminance unevenness and color unevenness generated in each image display device by incorporating a brightness unevenness correction circuit has been proposed. (For example, refer to Patent Document 2).
Furthermore, a method has been proposed in which the illumination light emitted from the illumination device is divided into a plurality of partial light beams using a lens array, thereby stabilizing the illumination light itself and suppressing luminance unevenness (for example, patents). Reference 3).

JP-A-6-222324 Japanese Unexamined Patent Publication No. 7-50795 JP 11-281923 A

However, in the technique described in Patent Document 1, there is a greater possibility that the luminance unevenness range of the light source becomes larger than the effective range of luminance unevenness correction, and the luminance unevenness cannot be effectively suppressed. There is.
In addition, the technique described in Patent Document 2 requires a luminance unevenness and color unevenness correction circuit for each image display device, leading to a problem that the device is complicated and power consumption is increased.
Furthermore, the technique described in Patent Document 3 has a problem that stabilization of illumination light depends on the product accuracy of the lens array, and a high-intensity light source lamp is used to project a high-intensity image. There is a problem that it is necessary to light up at the maximum output, resulting in an increase in power consumption.

  An object of the present invention is to provide a projector capable of preventing luminance unevenness of a projected image, suppressing the output of a light source as necessary, and reducing power consumption.

The projector according to the present invention is
A lighting device having a first light source and a second light source;
A light modulation device that modulates a light beam emitted from the illumination device according to image information to form an optical image;
A projection optical device that projects an optical image formed by the light modulation device;
A light amount control means for controlling the light amounts of the first light source and the second light source,
The first light source illuminates a first area that is a part of an image forming area of the light modulation device;
The second light source illuminates a second area that is a part of an image forming area of the light modulation device.

According to the present invention, since the image forming area of the light modulation device is divided and illuminated by the first light source and the second light source, the luminance is adjusted by adjusting the illumination intensity in each illumination area of the projection image. Generation of unevenness can be prevented.
Further, by controlling the light amount of each light source by the light amount control means, it is possible to control the light amount according to the environmental conditions for projecting the projection image and reduce the power consumption.
Furthermore, by controlling the light quantity of each light source by the light quantity control means, it is possible to reduce the load on the light source and prolong the life of the light source.

In the present invention,
The image forming area, the first area, and the second area are rectangular.
Preferably, the centers of the first area and the second area are outside the center of the image forming area, and the first area and the second area are partially overlapped.
According to the present invention, when the light source is a point light source, it tends to diminish as it goes away from the peak of the illumination intensity, and the influence of dimming can be reduced by overlapping a part of the illumination areas of adjacent light sources. Since the amount of light in the overlapped area can be improved by complementary interpolation, the amount of light in the entire projected image can be improved, and the illumination intensity peak of the point light source can be adjusted by adjusting the illumination intensity in the overlapped area. The brightness can be the same as the amount of light in the portion, and the occurrence of uneven brightness can be prevented.

In the present invention,
An imaging device that captures a projected image projected from the projection optical device;
Preferably, the light amount control means displays a single color image having an intermediate gradation value by the light modulation device, and performs light amount control of each light source based on imaging data obtained by imaging the single color image by the imaging device.
According to this invention, the light quantity control means displays a single-color image having an intermediate gradation value, and controls the light quantity of each light source based on the imaging data obtained by imaging it, so that the light quantity of each light source is set. The balance can be adjusted. Moreover, it is also possible to automate the light amount adjustment inside the projector by using the imaging device as imaging data.

FIG. 2 is a schematic diagram illustrating a structure of a projector according to an embodiment of the invention. FIG. 6 is a schematic diagram and a graph for explaining divided illumination of an image forming region of the light modulation device in the embodiment. FIG. 3 is a schematic diagram illustrating an illumination state of an image forming area of the light modulation device according to the embodiment. The block diagram showing the structure of the control means which controls the illuminating device in the said embodiment. The flowchart for demonstrating the effect | action of the said embodiment. The schematic diagram showing the state of the diagonal projection by the projector in the said embodiment. The schematic diagram showing the distribution of the brightness of the projection image at the time of performing oblique projection with the projector in the said embodiment. The graph for demonstrating the illumination intensity setting at the time of performing the oblique projection by the projector in the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(1) Structure of Optical System FIG. 1 shows an optical system of a projector 1 according to an embodiment of the present invention. This projector 1 transmits a light beam emitted from an illumination device 2 by a light modulation device 5. It is an optical device that modulates according to input image information to form an optical image and projects the image onto the screen S from the projection optical device 7. The projector 1 includes an illumination device 2, a color separation optical device 3, a relay optical device 4, a light modulation device 5, a color synthesis optical device 6, and a projection optical device 7.

The illumination device 2 includes two sets of illumination optical devices 2L and 2R arranged in parallel. The first illumination optical device 2L as the first light source includes a light source device 21L, a first lens array 22L, a second lens array 23L, a polarization conversion element 24L, and a superimposing lens 25L.
The light source device 21L includes a discharge arc tube 211L and a reflector 212R.
The discharge-type arc tube 211L is an ultra-high pressure mercury lamp, and has a pair of electrodes disposed therein, and a light-emitting portion in which a discharge space in which mercury is enclosed is formed, and extends in a direction away from each other across the light-emitting portion. And a pair of sealing portions each provided with an electrode lead wire connected to each electrode.
The reflector 212L is an optical element that reflects and converges the radiated light beam emitted from the discharge arc tube 211L to a predetermined position. In the present embodiment, an ellipsoidal reflector having a spheroid is adopted.

Each of the first lens array 22L and the second lens array 23L has a configuration in which corresponding small lenses are arranged in a matrix, and the first lens array 22L converts the light beam incident from the light source device 21L into a plurality of partial light beams. The image is divided and imaged in the vicinity of the second lens array 23L.
The second lens array 23L, together with the superimposing lens 25L located in the latter stage of the optical path, is arranged on the left half region 511L of the image forming region 511 of each liquid crystal panel 51R, 51G, 51B of the light modulation device 5 described later. A plurality of partial light beams divided by 22L are superimposed.

The polarization conversion element 24L is an optical element that converts the light beam emitted from the second lens array 23L into approximately one type of linearly polarized light beam.
This polarization conversion element 24L is a plate-like body formed by joining a plurality of prisms having a parallelogram cross section with one diagonal being 45 degrees and the other diagonal being approximately 135 degrees. Polarization separation films and total reflection mirrors are alternately deposited on the interface.
A plurality of half-wave retardation plates are provided at a predetermined pitch on the light exit surface of the polarization conversion element 24L.

In such a polarization conversion element 24L, when a light beam is incident on the surface on which the polarization separation film is formed, one of the two types of linearly polarized light beam is transmitted as it is and emitted, and the other polarized light beam is emitted. Is bent at a substantially right angle by the polarization separation film, and is bent again at a right angle by the total reflection mirror and emitted.
The polarization direction of either of the two types of linearly polarized light beams is converted by 90 deg by a half-wave retardation plate provided at the subsequent stage, so that the incident light beam can be converted into one type of linearly polarized light beam. Become.
The second illumination optical device 2R as the second light source is also composed of the same structure and parts as the first illumination optical device 2L, and includes a light source device 21R, a first lens array 22R, a second lens array 23R, and a polarization conversion element. 24R and a superimposing lens 25R.
The light beam emitted from the illumination device 2 is divided into a plurality of partial light beams, and the light beam whose polarization direction is aligned is emitted to the color separation optical device 3.

The color separation optical device 3 has a function of separating the light beam emitted from the illumination device 2 into three color lights of red light (R), green light (G), and blue light (B), and the dichroic mirrors 31 and 32. , And reflecting mirrors 33, 34, and 35.
The dichroic mirrors 31 and 32 are optical elements that are arranged with an inclination of approximately 45 degrees with respect to the optical path center axis of the light flux, and are formed with a dielectric multilayer film on a transparent substrate such as BK7 or quartz glass. The dielectric multilayer films of the dichroic mirrors 31 and 32 have a function of reflecting a light beam in a specific wavelength region, transmitting other light beams, and separating the light beam into a plurality of color lights. The dichroic mirror 31 arranged at the front stage of the optical path reflects red light (R) and transmits the other green light (G) and blue light (B), while the dichroic mirror 32 arranged at the rear stage of the optical path is , Green light (G) is reflected and blue light (B) is transmitted.

The reflection mirrors 33, 34, and 35 are optical elements that guide the red light (R) and the blue light (B) separated by the dichroic mirrors 31 and 32 to the liquid crystal panels 51 </ b> R and 51 </ b> B that constitute the light modulation device 5. Consists of a total reflection mirror.
A relay optical device 4 is provided in the optical path of the blue light (B) separated by the color separation optical device 3, and the relay optical device 4 is provided by two condensing lenses 41 and 42 arranged in the optical path. It has a function of guiding the blue light (B) to the liquid crystal panel 61B on the blue light side.
On the other hand, each color light of red light (R) and green light (G) separated by the color separation optical device 3 is incident on the liquid crystal panels 51R, 51G, 51B constituting the light modulation device 5 through the field lens 43. To do.

Although not shown, the light modulation device 5 includes three liquid crystal panels 51R, 51G, and 51B. And an exit-side polarizing plate.
The liquid crystal panels 51R, 51G, and 51B have an image forming area 511 in which liquid crystal that is an electro-optical material is hermetically sealed in a pair of transparent glass substrates. In the image forming area 511, the image forming area 511 corresponds to input image information. By controlling the alignment state of the liquid crystal, the polarization direction of the linearly polarized light beam transmitted through the incident side polarizing plate is modulated. Among the light beams modulated by the liquid crystal panels 51R, 51G, and 51B, a predetermined linearly polarized light beam is transmitted through the exit-side polarizing plate, and the other polarized light beams are absorbed by the exit-side polarizing plate to form an optical image. The light beam modulated by the light modulation device 5 is emitted to the color synthesis optical device 6.

The color synthesizing optical device 6 has a function of synthesizing the modulated light beams emitted from the respective emission side polarizing plates to form a color image, has a substantially square shape in plan view in which four right angle prisms are bonded, and has a right angle. It is configured as a cross dichroic prism in which two dielectric multilayer films are formed at the interface where the prisms are bonded together.
One of the two dielectric multilayer films reflects red light (R) and transmits green light (G), and the other reflects blue light (B) and transmits green light (G). These dielectric multilayer films combine red light (R), green light (G), and blue light (B) to form a color image.
Although not shown in FIG. 1, the projection optical device 7 is composed of a combination lens in which a plurality of lenses are arranged in the lens barrel with the optical axis aligned, and an optical image synthesized by the color synthesis optical device 6 is screened. Project onto S.

In the projector 1 having such a structure, the illuminating device 2 described above divides the rectangular image forming region 511 of the liquid crystal panels 51R, 51G, 51B constituting the light modulation device 5 as shown in FIG. It comes to illuminate.
That is, the first illumination optical device 2L illuminates the left half region (first region) 511L of the image forming region 511 of each of the liquid crystal panels 51R, 51G, 51B, and the second illumination optical device 2R The right half area (second area) 511R of the image forming area 511 is illuminated. That is, the first light source 2L illuminates the first area 511L that is a part of the image forming area 511, and the second light source 2R illuminates the second area 511R that is a part of the image forming area 511.
The discharge-type light emitting tubes 211L and 211R of the illumination optical devices 2L and 2R are disposed outside the center line CL of the image forming area 511. The left half area 511L and the right half area 511R correspond to the image forming area 511. The illumination areas are overlapped at the central portion to form an overlap area 511C. Accordingly, the first region 511L and the second region 511R are partially overlapped.

Since the discharge arc tubes 211L and 211R of both the illumination optical devices 2L and 2R are point light sources, as shown in the graphs L and R in FIG. 2, the discharge arc tube 211L has an illumination corresponding to the arrangement position thereof. The illumination intensity is highest in the region, and has an illumination characteristic that gradually decreases as the distance from the region increases. Similarly, the discharge arc tube 211R has the highest illumination intensity in the illumination region corresponding to the arrangement position. It has a lighting characteristic that gradually fades away from it.
However, as shown in FIG. 2, since the overlapping regions 511C are formed in both illumination optical devices 2L and 2R, the illumination light of both illumination optical devices 2L and 2R overlaps in this overlapping region 511C. Both illumination lights are complementarily interpolated to increase the amount of light.
As a result, as shown in FIG. 3, only the corner area E of the image forming area 511 is affected by the light reduction, but it is possible to uniformly illuminate substantially the entire area of the image forming area 511.

(2) Structure of the light quantity control means 10 The projection image projected from the projector 1 described above is picked up by the CCD camera 8 as shown in FIG. The light quantity control means 10 performs drive control of the light source drive circuits 9L and 9R based on the imaging data. The light quantity control unit 10 includes an imaging data capturing unit 11, a light quantity analysis unit 12, a light quantity setting unit 13, and a light quantity control unit 14. The light quantity control unit 10 receives information from the memory 15 as necessary. The read or generated data can be written into the memory 15. The light quantity control unit 10 is an arithmetic processing unit, and the imaging data fetching unit 11, the light quantity analysis unit 12, the light quantity setting unit 13, and the light quantity control unit 14 constituting the light quantity control unit 10 are executed by the light quantity control unit 10. The program is read from the memory 15 when the projector 1 is activated.

The imaging data capturing unit 11 is a part that captures a projection image of the projector 1 captured by the CCD camera 8 as data.
The light quantity analysis unit 12 is a part that analyzes the luminance distribution of the projection image based on the imaging data of the captured projection image. The light quantity analysis can use a known luminance distribution analysis method. This is done by making the luminance data of each pixel in the data into a histogram.
The light amount setting unit 13 is a part for setting the light amounts of the first illumination optical device 2L and the second illumination optical device 2R of the illumination device 2 based on the luminance distribution analyzed by the light amount analysis unit 12, and is a projection image. If there is a bias in the luminance distribution in the left and right areas, improve the illumination intensity of the illumination optical apparatus that illuminates the dark illumination area, or decrease the illumination intensity of the illumination optical apparatus that illuminates the bright illumination area, The light quantity of the illumination device 2 is set so that the overall illumination intensity is uniform.

  The light amount control unit 14 is a part that performs light amount control of the first illumination optical device 2L and the second illumination optical device 2R based on the set value set by the light amount setting unit 13. The light quantity control unit 14 outputs a control command to the light source drive circuits 9L and 9R that drive the discharge arc tubes 211L and 211R, thereby controlling the light quantity of the light beam emitted from the discharge arc tubes 211L and 211R. Specifically, the voltage applied to the discharge arc tubes 211L and 211R is output as a control command, and the light source drive circuits 9L and 9R drive the discharge arc tubes 211L and 211R based on the applied voltage. As a result, the amount of light emitted from the discharge arc tubes 211L and 211R is changed.

(3) Operation and Effect of Embodiment Next, the operation of the projector 1 having the above-described structure will be described based on the flowchart shown in FIG.
The light quantity control means 10 reads the single color image stored in the memory 15 together with the activation of the projector 1, and projects the single color image on the screen S (step S1). The “monochromatic image” in the present invention refers to an image whose entire surface has the same color and the same gradation. As the monochromatic image, a gray image having an intermediate gradation can be adopted so that light and darkness can be easily understood.
Next, the CCD camera 8 captures the projected monochromatic image, and the imaging data capturing unit 11 captures the imaging data captured by the CCD camera 8 as digital data (step S2).
The light amount analysis unit 12 performs light amount analysis of the projection image based on the imaging data, and acquires the luminance distribution of the projection image (step S3).

The light amount setting unit 13 sets the light amount of the light beam emitted from the discharge arc tubes 211L and 211R of the illumination optical devices 2L and 2R based on the luminance distribution of the projection image by the light amount analysis unit 12 (step S4).
The light quantity control unit 14 outputs a control command to the light source driving circuits 9L and 9R based on the light quantity emitted from the discharge type light emitting tubes 211L and 211R set by the light quantity setting unit 13, and each discharge type light emitting tube 211L and 211R. The amount of light emitted from the light source is controlled (step S5).

  According to the projector 1 according to the present embodiment, for example, as illustrated in FIG. 6, when the projector 1 and the screen S are not completely facing each other, so-called oblique projection, the projector 1 to the screen S is used. Therefore, as shown in FIG. 7, the brightness of the projected image G is biased on the left and right. In the case of FIG. 6, since the left projection area is closer than the right projection area, the left area of the projection image G is brighter than the right area.

Therefore, as shown in FIG. 8, the light amount control means 10 reduces the illumination intensity of the first illumination optical device 2 </ b> L and increases the illumination intensity of the second illumination optical device 2 </ b> R. Since the amount of light in the bright left region decreases, the brightness of the projected image G can be made uniform as a whole, and the occurrence of uneven brightness can be prevented.
In addition, since the illumination intensity of the first illumination optical device 2L that performs close-up illumination is reduced, the power consumption of the first illumination optical device 2L can be reduced accordingly.

(4) Modification of Embodiments The present invention is not limited to the above-described embodiment, and includes modifications as described below.
Although the illumination device 2 according to the above-described embodiment divides and illuminates the left and right sides of the image forming regions 511 of the liquid crystal panels 51R, 51G, and 51B, the present invention is not limited to this. In other words, the illumination device may be configured to divide the upper and lower sides of the image forming area of the liquid crystal panel, and further, the image forming area of the liquid crystal panel may be divided into four to divide and illuminate the four areas. .

Further, in the above-described embodiment, the illumination device 2 that performs divided illumination is employed in the projector 1 that includes the three liquid crystal panels 51R, 51G, and 51B. However, the present invention is not limited to this. That is, the present invention can be applied to a single-plate type liquid crystal projector. Further, as a light modulation method of the light modulation device, not only a transmission type but also a light modulation using a reflection type liquid crystal panel or a micromirror. The present invention may be applied to an apparatus.
In addition, the specific structure and shape of the present invention may be other structures and the like as long as the object of the present invention can be achieved.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Illumination device, 2L ... 1st illumination optical device, 2R ... 2nd illumination optical device, 3 ... Color separation optical device, 4 ... Relay optical device, 5 ... Light modulation device, 6 ... Color composition Optical device, 7 ... Projection optical device, 8 ... CCD camera, 9L, 9R ... Light source drive circuit, 10 ... Light quantity control means, 11 ... Imaging data fetching section, 12 ... Light quantity analysis section, 13 ... Light quantity setting section, 14 ... Light quantity control unit, 15 ... Memory, 21L, 21R ... Light source device, 22L, 22R ... First lens array, 23L, 23R ... Second lens array, 24L, 24R ... Polarization conversion element, 25L, 25R ... Superimposing lens, 31, 32 ... Dichroic mirror, 33, 34, 35 ... Reflective mirror, 4142 ... Condensing lens, 43 ... Field lens, 51R, 51G, 51B ... Liquid crystal panel, 211L, 211R ... Discharge type light emission 212L, 212R ... reflector, 511 ... image forming area, 511L ... left half area, 511R ... right half area, 511C ... overlapping area, CL ... center line, E ... corner corner area, G ... projected image, S ... Screen

Claims (3)

A lighting device having a first light source and a second light source;
A light modulation device that modulates a light beam emitted from the illumination device according to image information to form an optical image;
A projection optical device that projects an optical image formed by the light modulation device;
A light amount control means for controlling the light amounts of the first light source and the second light source,
The first light source illuminates a first area that is a part of an image forming area of the light modulation device;
The projector according to claim 1, wherein the second light source illuminates a second area that is a part of an image forming area of the light modulation device. The projector according to claim 1.
The image forming area, the first area, and the second area are rectangular.
The centers of the first area and the second area are outside the center of the image forming area, and the first area and the second area are partially overlapped with each other. projector. The projector according to claim 1 or 2,
An imaging device that captures a projected image projected from the projection optical device;
The light quantity control means displays a single color image of an intermediate gradation value by the light modulation device, and performs light quantity control of each light source based on imaging data obtained by imaging the single color image by the imaging device. projector.

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