JP2005159641A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector whereby the recognition performance of a projected moving picture is improved and the luminous quantity of a projected image can be enhanced. <P>SOLUTION: The projector including: a light source unit; a hold type optical modulator for modulating luminous flux emitted from the light source unit in accordance with image information including the moving picture to form an optical image; and a projection optical system for magnifying and projecting the formed optical image, is provided with: light source lamps 416A, 416B; reflecting mirrors located at surroundings of the light source lamps 416A, 416B and arranged so that illumination regions of the luminous flux emitted from the light source lamps 416A, 416B are almost overlapped with each other; and a light source turning on/off control section 51 for turning on/off at least one of the light source lamps 416A, 416B in accordance with the switching timing of frames configuring the moving picture included in received image information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light source device, a hold type light modulation device that modulates a light beam emitted from the light source device according to image information including a moving image to form an optical image, and an enlarged projection of the formed optical image. The present invention relates to a projector including a projection optical system.

Conventionally, liquid crystal projectors are used for presentations at conferences, academic conferences, exhibitions, etc., and for watching movies at home. Such a liquid crystal projector is usually provided with a light source device having one light source lamp in an exterior case, and a light beam emitted from the light source device is irradiated to a liquid crystal panel as a light modulation device. Thus, the optical image formed according to the image information is enlarged and projected by the projection optical system.
However, among the components constituting such a liquid crystal projector, a liquid crystal panel, particularly an active matrix type liquid crystal panel using thin film transistors (TFTs), holds a liquid crystal panel that holds an image until each pixel is refreshed. Is often used, and a light source device that is continuously illuminated is often used as the light source device. For this reason, in such a configuration, a tailing phenomenon occurs when the formed optical image is projected, and an afterimage is recognized in the projected moving image, so that there is a problem that the moving image recognizability is low.

  In order to solve such a problem of moving image recognition, a method has been proposed in which a light beam is intermittently emitted from a light source device to a liquid crystal panel to provide intermittent illumination. As one of such methods, a belt in which a transmission film that transmits a light beam and a blocking film that blocks the light beam are alternately moved on the optical path, and the light beam emitted to the liquid crystal panel is used as intermittent illumination. An image display device has been proposed (see, for example, Patent Document 1). Such an image display device is mainly intended for a liquid crystal display. In this image display device, the periphery of a backlight that emits a light beam to the liquid crystal panel is covered with the belt described above, and the belt is moved by a motor. As a result, the light flux emitted from the backlight to the liquid crystal panel is used as intermittent illumination to suppress the afterimage of the projected image.

  However, when such a mechanism is employed in a projection-type projector, the light beam emitted from the light source device reaches the liquid crystal panel only when the transmission film formed on the belt moves on the optical path. When the blocking film moves on the optical path, the luminous flux emitted from the light source device is not used for forming an optical image, so that there is a problem that the light amount of the projected image is reduced.

  For this problem, it is conceivable to apply a configuration in which a plurality of light source lamps are provided in the light source device (see, for example, Patent Document 2). In this configuration, light beams emitted from a plurality of light source lamps are condensed into one light beam to increase the light amount of the projected image. Therefore, in order to solve the above-described problems in moving image recognition and reduction in the amount of light of the projected image, a belt as described above is disposed in each of the plurality of light source lamps, and each belt is rotated to remove the light source lamp. A configuration for improving the moving image recognizability and the amount of light by using the emitted light beam as intermittent illumination is conceivable.

JP 11-119149 A JP 2001-159871 A

However, as described above, when the combination of the configurations described in Patent Document 1 and Patent Document 2 is used in a projector in order to improve moving image recognition and increase the amount of light of a projected image, the surroundings of the light source device Therefore, there is a problem that the structure is complicated and it is difficult to arrange the light source device in the projector. Further, in the case where the configuration of Patent Document 1 and the configuration of Patent Document 2 are combined, even if a plurality of light source lamps are provided, the light beams emitted from the respective light source lamps are shielded by the belt, and the light beams are substantially omitted. Since all cannot be used for forming an optical image, there is a problem that it is not so effective in improving the light amount of a projected image.
For this reason, there has been a demand for a projector that suppresses an afterimage of a projected image, improves moving image recognition, and improves the amount of light of the projected image.

  An object of the present invention is to provide a projector capable of improving the recognizability of a projected moving image and improving the amount of light of a projected image.

  The projector according to the present invention includes a light source device, a hold type light modulation device that modulates a light beam emitted from the light source device in accordance with image information including a moving image to form an optical image, and an enlarged optical image. A projector having a projection optical system for projecting, wherein the light source device is provided with a plurality of light source lamps and a light beam emitted from each of the plurality of light source lamps. And at least one of the plurality of light source lamps is turned on / off according to the switching timing of the frames constituting the moving image included in the input image information. A light source lighting / extinguishing control unit is provided.

  According to the present invention, the light source on / off control unit controls the on / off of a plurality of light source lamps provided in the light source device in accordance with the frame switching timing included in the image information input to the hold type light modulation device. it can. Here, as a factor of the tailing phenomenon of the moving image, the light beam irradiated from the light source device to the hold type light modulation device can be continuously lit, thereby enabling the switching of each frame constituting the moving image. The light modulation device is irradiated with the light beam, which causes a residual image phenomenon in a moving image to be projected. On the other hand, the light source on / off control unit turns on / off at least one of a plurality of light source lamps provided in the light source device in accordance with the frame switching timing, thereby causing an afterimage resulting from the tailing phenomenon of the moving image. The phenomenon can be suppressed and the video recognition can be improved.

  In general, when the light source lamp is repeatedly turned on and off, the amount of light emitted from the light source lamp decreases as the number of lighting operations per unit time increases. However, the light source device of the projector according to the present invention is provided with a plurality of light source lamps. According to this, since the turn-on / off of each light source lamp is separately repeated, the number of times of light emission per unit time of each light source lamp can be suppressed as compared to the case where the light source lamp is repeatedly turned on / off. The amount of light emitted per light emission can be improved. Accordingly, it is possible to improve the light amount of the projected optical image.

  Further, the light beam emitted from the light source lamp is incident on a part of the image forming area of the light modulation device, and the light beam emitted from the light source lamp when the blocking film moves on the optical path forms an optical image. In contrast to a structure using a belt that is not used for the projector, in the projector of the present invention, a plurality of light source lamps provided in the light source device are arranged so that illumination areas of light beams emitted from the respective light source lamps are substantially overlapped. It is. According to this, it is possible to irradiate the image forming area of the light modulation device with substantially all of the light beam emitted from the light source lamp. Therefore, the light quantity of the projected moving image can be improved while improving the moving image recognizability as compared with the projector having the conventional structure.

In addition, since the light source on / off control unit controls the on / off of the light source lamp, there is no need to use a conventional belt for intermittent illumination. Therefore, the structure of the light source device can be simplified, and as a result, the structure inside the projector can be simplified.
Furthermore, since a plurality of light source lamps are provided in the light source device, even if one light source lamp fails, the moving image recognizability can be ensured by performing on / off control of the other light source lamps.

In the present invention, it is preferable that the light source on / off control unit sequentially switches on and turns on the plurality of light source lamps, and synchronizes a cycle in which all of the plurality of light source lamps are turned on with the frame switching cycle.
In this case, the light source device includes two light source lamps, and the light source on / off control unit sets the light emission frequency of each of the light source lamps to approximately 30 Hz, and one of the two light source lamps. It is preferable to set the light emission period with a shift of about 60 Hz with respect to the other.
According to the present invention, the light source on / off control unit sets the light emission frequencies of the two light source lamps to about 30 Hz, and the light emission cycle is shifted by about 60 Hz. 60 Hz. Here, a moving image is generally composed of 30 frame images per second. Also, since the human eye has a characteristic that the viewpoint follows the moving luminance in the moving image, a lighting frequency of 60 Hz is preferable in order not to feel flicker (flicker) in the moving image. Below this, particularly at 30 Hz or less, it becomes easy to recognize the flicker of the image, and the moving image recognizability is remarkably lowered. Therefore, by setting the frequency of the luminous flux emitted from the two light source lamps to 60 Hz, the frame switching timing and the light emission timing of the light source lamp are synchronized, so that the afterimage phenomenon can be suppressed and the projected optical image Flicker can be suppressed and moving image recognition can be improved.

As described above, when a general light source lamp is turned on per unit time, the amount of emitted light decreases. That is, if the maximum lamp input power amount is the same, when the light emission frequency of the light source lamp is increased, the lamp input voltage decreases and the amount of light generated by one light emission decreases. Exists. For this characteristic, two light source lamps are provided, and each of them is turned on and off separately, whereby the lamp input voltage input to each light source lamp can be increased, and the amount of light when one light source lamp emits light is increased. be able to. Therefore, it is possible to increase the light emission amount of the light source lamp, and consequently increase the light amount of the moving image to be projected, and improve the moving image recognition. Further, since the number of times of light emission per unit time of each light source lamp can be reduced as compared with the case where one light source lamp is intermittently turned on at 60 Hz, the life of each light source lamp can be extended.
In addition, as described above, even when one of the light source lamps cannot be driven due to a failure or the like, the light source on / off control unit intermittently lights the other light source lamp at 60 Hz to ensure video recognition. In this case, it is possible to control a case where the amount of light of a moving image projected by intermittently lighting at 30 Hz is secured.

In the present invention, the light source lamp is preferably a flashlight having an intermittent lighting mode in which the light source lamp is lit at a light emission frequency of about 30 Hz and a continuous lighting mode.
According to the present invention, the flashlight has an intermittent lighting mode in which the light emission frequency is 30 Hz and is turned on and off, and a continuous lighting mode, whereby intermittent lighting and continuous lighting can be selected and performed. For this reason, the light source on / off control unit simply switches the flashlight lighting method between the case where the input information is moving image information and the case where the information is still image information. Can be formed. Therefore, the control by the light source on / off control unit can be simplified.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(1) External Configuration FIG. 1 is a perspective view of a projector 1 according to the present embodiment as viewed from the upper front side. FIG. 2 is a perspective view of the projector 1 as viewed from the lower front side. FIG. 3 is a perspective view of the projector 1 as seen from the rear rear side. FIG. 4 is a perspective view showing a part of the outer case 2 of the projector 1.
The projector 1 modulates the light beam emitted from the light source according to the image information, and enlarges and projects it on a projection surface such as a screen. As shown in FIGS. 1 to 3, the projector 1 includes a substantially rectangular parallelepiped outer case 2 and a projection lens 3 exposed from the outer case 2.
The projection lens 3 has a function as a projection optical system for enlarging and projecting an optical image modulated and formed by a liquid crystal panel as a light modulation device to be described later, and a plurality of lenses are housed in a lens holding cylinder. It is configured as a combined lens.

The outer case 2 is a synthetic resin-made outer casing having a substantially rectangular planar shape, and houses the apparatus main body including the optical unit (described later) of the projector 1. The outer case 2 includes an upper case 21 that covers the upper part of the apparatus main body, a lower case 22 that covers the lower part of the apparatus main body, a front case 23 that covers the front part of the apparatus main body, and a part of the side part of the apparatus main body. And a rear case 25 (see FIG. 3) for covering the back portion of the apparatus main body.
Note that the corners of the top surface, front surface, side surface, bottom surface, and back surface of the exterior case 2 are formed in a curved surface.
The upper case 21 has a substantially rectangular upper surface portion 21A covering the upper part of the apparatus main body, a side surface portion 21B substantially hanging from one end portion in the long side direction of the upper surface portion 21A, and a long side direction of the upper surface portion 21A. A side surface portion 21C that substantially hangs down from the front portion of the other end portion of the other and a back surface portion 21D (see FIG. 3) that hangs down substantially from the rear end portion of the upper surface portion 21A.
As shown in FIG. 1 or FIG. 3, an operation panel 26 that performs the start-up / adjustment operation of the projector 1 is provided at a substantially central portion on the rear side of the upper surface portion 21A so as to extend in the left-right direction. When the operation button 261 on the operation panel 26 is appropriately pressed, the tact switch mounted on a circuit board (not shown) disposed inside the operation panel 26 is brought into contact with, and a desired operation can be performed. In addition, an LED (not shown) is attached to the circuit board so as to emit light according to a desired operation.
Further, the operation panel 26 includes a decorative plate 262 disposed so as to surround the operation button 261, and light from the LED is diffused through the decorative plate 262.

Further, from the front side (right side in FIG. 1) of the upper surface portion 21A, the projection lens 3 is moved up, down, left, and right to adjust the position of the projection lens 3 to constitute two projection lens position adjusting devices 30 (see FIG. 4). Dials 311 and 321 are exposed. When the dial 311 arranged on the left side of FIG. 1 is moved in the Y1 direction (downward) of the two dials 311 and 321, the projection lens 3 moves in the Y3 direction (downward), and the dial 311 moves in the Y2 direction (upward). When moved, the projection lens 3 moves in the Y4 direction (upward).
When the dial 321 arranged on the right side of FIG. 1 is moved in the X1 direction (rightward when viewed from the rear of the projector 1), the projection lens moves in the X3 direction (rightward), and the dial 321 is viewed in the X2 direction (viewed from the rear of the projector 1). The leftward direction), the projection lens 3 moves in the X4 direction (leftward).
Further, although not shown, a rib surrounding the outer periphery of the projection lens 3 is erected on the inner surface side of the upper surface portion 21A.

The side surface portion 21 </ b> C is formed with a notch 21 </ b> C <b> 1 in which the louver 71 composed of a plurality of blades 711 is exposed.
Further, as shown in FIG. 3, the back surface portion 21D is formed with a notch 21D1 with which the rear case 25 is engaged.

As shown in FIGS. 1 to 4, the lower case 22 includes a bottom surface portion 22A, side surface portions 22B and 22C, a back surface portion 22D, and a front surface portion 22E.
The bottom surface portion 22A has a substantially rectangular shape in plan, and a fixed leg portion 22A1 is provided at the substantially rear center of the projector 1 of the bottom surface portion 22A, and adjustment leg portions 27 are provided at both ends on the front side in the long side direction. ing.
The adjustment leg 27 includes a shaft-like member 271 (see FIG. 5) that protrudes forward and backward in the out-of-plane direction from the bottom surface 22 </ b> A, and the projector 1 is tilted in the vertical and horizontal directions during projection. Can be adjusted.
In addition, an opening 22A3 that communicates with the inside of the exterior case 2 is formed in the bottom surface portion 22A.
The opening 22A3 is an intake port for taking cooling air outside the outer case 2 into the outer case 2, and a cover 22A5 having a plurality of openings is attached to the opening 22A3.
Further, as shown in FIG. 4, a rib 22A6 is provided on the bottom surface portion 22A so as to surround the outer periphery of the projection lens 3.

The side surface portion 22B is erected from one end portion of the bottom surface portion 22A in the long side direction, and engages with the side surface portion 21B of the upper case 21 as shown in FIG. Configure the side.
The side surface 22B is formed with a recess 22B1 that is recessed toward the upper case 21. The recess 22B1 is used as a grip when the projector 1 is gripped.
As shown in FIG. 1, the side surface portion 22C is erected from the front side portion of the other end portion in the long side direction of the bottom surface portion 22A, and engages with the side surface portion 21C of the upper case 21, A part of the side surface of the outer case 2 is formed. The upper end of the side surface portion 22C is greatly cut, and the louver 71 is exposed from the notch 22C1. That is, an opening through which the louver 71 is exposed is formed by the notch 21C1 of the side surface portion 21C and the notch 22C1 of the side surface portion 22C. From this opening, the air that has cooled the inside of the projector 1 is discharged.
As shown in FIG. 3, the back surface portion 22D is erected from one end portion in the short side direction of the bottom surface portion 22A, and the back surface portion 22D has a notch 22D1 with which the rear case 25 is engaged. Is formed. That is, in this embodiment, the back surface of the exterior case 2 is configured by the back surface portions 21D and 22D and the rear case 25.
A rectangular opening 22D2 is formed in the back surface portion 22D, and the inlet connector 22D3 is exposed from the opening 22D2. The inlet connector 22D3 is a terminal that supplies power to the projector 1 from an external power supply, and is electrically connected to a power supply unit described later.
Again, as shown in FIG. 1, the front surface portion 22E is erected from the other end portion in the short side direction of the bottom surface portion 22A. The front surface portion 22E engages with the front case 23, and these constitute the front surface of the exterior case 2.

As shown in FIGS. 1 and 2, the front case 23 has a substantially oval shape, and an opening 231 for exposing the projection lens 3 is formed on the longitudinal end portion side (right side in FIG. 1). Although not shown here, the projection lens 3 exposed from the opening 231 includes a first light shielding member that closes a gap between the opening 231 and the outer periphery of the projection lens 3, and the projection lens 3 and the projection lens position adjusting device 30. A second light-shielding member 12 (see FIG. 4) for closing the gap between the two is attached.
Further, a remote control light receiving window 232 is formed at a substantially central portion of the front case 23. A remote control light receiving module (not shown) that receives an operation signal from a remote controller (not shown) is disposed inside the remote control light receiving window 232.
The remote controller is provided with the same start switch, adjustment switch and the like provided on the operation panel 26 described above. When the remote controller is operated, an infrared signal corresponding to this operation is output from the remote controller. The infrared signal is received by the light receiving unit through the remote control light receiving window 232 and processed by a control board described later.
Further, as shown in FIG. 4, ribs 234 are erected on the inner surface of the front case 23 so as to surround the outer periphery of the projection lens 3, and the ribs 234, the ribs 22 </ b> A <b> 6 of the bottom surface portion 22 </ b> A of the lower case 22, A lens chamber surrounding the projection lens 3 is formed by the rib of the upper surface portion 21A of the case 21.

As shown in FIGS. 1 and 3, the side case 24 includes an upper surface portion 24A and a side surface portion 24C that is substantially suspended from the upper surface portion 24A. The upper surface portion 24 </ b> A is engaged with the upper surface portion 21 </ b> A of the upper case 21 to constitute the upper surface of the exterior case 2.
The side surface portion 24 </ b> C engages with the side surface portion 21 </ b> C of the upper case 21 and the side surface portion 22 </ b> C of the lower case 22.

As shown in FIG. 3, the rear case 25 is fitted and fixed in an opening formed by a notch 21D1 of the back surface portion 21D of the upper case 21 and a notch 22D1 of the back surface portion 22D of the lower case 22. It is.
The rear case 25 has a substantially rectangular planar shape, and a remote control light receiving window 232 similar to the front case 23 is formed in the vicinity of the end in the longitudinal direction.
The rear case 25 is formed with a recess 251 that is recessed toward the inside of the exterior case 2, and a plurality of connection terminals 252 are exposed from the recess 251.
The connection terminal 252 is used to input an image signal, an audio signal, and the like from an external electronic device. The connection terminal 252 is connected to an interface board located inside the rear case 25.
The interface board is electrically connected to a control board, which will be described later, and a signal processed by the interface board is output to the control board.

(2) Internal Configuration FIG. 5 is a diagram showing an internal configuration of the projector 1. Specifically, only the lower case 22 of the outer case 2 is left, and the upper case 21, the front case 23, the side case 24, and the rear case 25 are removed.
The exterior case 2 accommodates the main body of the projector 1, and the main body is disposed above the optical unit 4 and an optical unit 4 extending in the left-right direction along the longitudinal direction of the exterior case 2. The control board 5 and the power supply unit 6 are provided.

(2-1) Structure of Optical Unit 4 FIG. 6 is a diagram schematically showing the optical unit 4.
The optical unit 4 modulates the light beam emitted from the light source device according to image information to form an optical image, and forms a projected image on the screen via the projection lens 3. As shown in FIG. 6, the optical unit 4 includes an integrator illumination optical system 41, a color separation optical system 42, a relay optical system 43, an optical device 44 in which a light modulation device and a color synthesis optical device are integrated, These optical components 41, 42, 43, and 44 are functionally broadly divided into optical component casings (not shown) that house and arrange the optical components 41, 42, 43, and 44.
The integrator illumination optical system 41 is an optical system for making the luminous flux emitted from the light source uniform in the illumination optical axis orthogonal plane. The integrator illumination optical system 41 includes a light source device 411, a first lens array 412, a second lens array 413, a polarization conversion element 414, and a superimposing lens 415.

The light source device 411 includes a first light source device 411A and a second light source device 411B as radiation sources, and a prism 411C that guides light beams emitted from the first light source device 411A and the second light source device 411B to the first lens array 412. It has.
The first light source device 411A includes a light source lamp 416A, a reflector 417A as a reflecting mirror, and an explosion-proof glass 418A that covers a light-emitting surface of the reflector 417A. Then, the radial light beam emitted from the light source lamp 416A is reflected by the reflector 417A to become a substantially parallel light beam, and passes through the explosion-proof glass 418A. This explosion-proof glass 418A is to prevent the fragments from scattering when the light source lamp 416A is broken.
In the present embodiment, a flash light is used as the light source lamp 416A, and a parabolic mirror is used as the reflector 417A. Here, the flash light is a light having an intermittent lighting mode and a continuous lighting mode. In the present embodiment, a flash light that intermittently lights at a light emission frequency of 30 Hz is employed in the intermittent lighting mode. Moreover, although the parabolic mirror is employ | adopted as reflector 417A, you may employ | adopt the structure which has arrange | positioned the collimating concave lens to the output surface of the reflector which consists of an ellipsoidal mirror not only in this.

The second light source device 411B has substantially the same configuration as the first light source device 411A, and includes a light source lamp 416B, a reflector 417B, and an explosion-proof glass 418B.
The first light source device 411A and the second light source device 411B are arranged so that the optical axes of the light beams emitted from the first light source device 411A and the second light source device 411B intersect at the approximate center of the light beam incident surface of the prism 411C. That is, in the first light source device 411A and the second light source device 411B, the illumination region of the light beam emitted from the first light source device 411A and the illumination region of the light beam emitted from the second light source device 411B are the light beams of the prism 411C. It arrange | positions so that it may substantially overlap with an entrance plane.
Further, the light source lamps 416A and 416B of the first light source device 411A and the second light source device 411B are connected to the light source on / off control unit 51 (FIG. 7) provided on the control board 5 described above, and the respective light source lamps 416A. , 416B is turned on and off. This on / off control will be described in detail later.

  The prism 411C is a substantially triangular prism having a substantially triangular cross section in the optical axis direction, and is formed such that the length of the substantially central portion in the optical axis direction increases from the light beam incident surface to the light beam exit surface. ing. The light beams emitted from the first light source device 411A and the second light source device 411B are emitted toward the first lens array 412 by the prism 411C.

The first lens array 412 has a configuration in which small lenses having a substantially rectangular outline when viewed from the illumination optical axis direction are arranged in a matrix. Each small lens splits the light beam emitted from the light source device 411 into partial light beams and emits them in the direction of the illumination optical axis.
The second lens array 413 has substantially the same configuration as the first lens array 412, and includes a configuration in which small lenses are arranged in a matrix. The second lens array 413 has a function of forming an image of each small lens of the first lens array 412 on liquid crystal panels 441R, 441G, and 441B described later of the optical device 44 together with the superimposing lens 415.

The polarization conversion element 414 converts the light from the second lens array 413 into approximately one type of polarized light, thereby improving the light use efficiency in the optical device 44.
Specifically, each partial light beam converted into substantially one type of polarized light by the polarization conversion element 414 is finally superimposed on liquid crystal panels 441R, 441G, 441B (to be described later) of the optical device 44 by the superimposing lens 415. . In a projector using liquid crystal panels 441R, 441G, and 441B of a type that modulates polarized light, only one type of polarized light can be used, and therefore approximately half of the light flux from the light source device 411 that emits randomly polarized light is not used. For this reason, by using the polarization conversion element 414, the light beam emitted from the light source device 411 is converted into substantially one type of polarized light, and the light use efficiency in the optical device 44 is enhanced. Such a polarization conversion element 414 is introduced in, for example, Japanese Patent Application Laid-Open No. 8-304739.

The color separation optical system 42 includes two dichroic mirrors 421 and 422 and a reflection mirror 423. A plurality of partial light beams emitted from the integrator illumination optical system 41 are separated into three color lights of red (R), green (G), and blue (B) by two dichroic mirrors 421 and 422.
The relay optical system 43 includes an incident side lens 431, a pair of relay lenses 433, and reflection mirrors 432 and 435. The relay optical system 43 has a function of guiding blue light, which is color light separated by the color separation optical system 42, to a liquid crystal panel 441B described later of the optical device 44.

  At this time, in the dichroic mirror 421 of the color separation optical system 42, among the light beams emitted from the integrator illumination optical system 41, the green light component and the blue light component are transmitted, and the red light component is reflected. The red light reflected by the dichroic mirror 421 is reflected by the reflection mirror 423, passes through the field lens 419, and reaches the red liquid crystal panel 441R. The field lens 419 converts each partial light beam emitted from the second lens array 413 into a light beam parallel to the central axis (principal ray). The same applies to the field lens 419 provided on the light incident side of the other liquid crystal panels 441G and 441B.

Of the blue light and green light transmitted through the dichroic mirror 421, the green light is reflected by the dichroic mirror 422, passes through the field lens 419, and reaches the liquid crystal panel 441G for green light. On the other hand, the blue light passes through the dichroic mirror 422, passes through the relay optical system 43, passes through the field lens 419, and reaches the blue light liquid crystal panel 441B.
The reason why the relay optical system 43 is used for blue light is that the optical path length of the blue 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. Because. That is, this is to transmit the partial light beam incident on the incident side lens 431 to the field lens 419 as it is. The relay optical system 43 is configured to pass blue light of the three color lights, but is not limited thereto, and may be configured to pass red light, for example.

  The optical device 44 modulates an incident light beam according to image information to form a color image. The optical device 44 includes three incident-side polarizing plates 442 to which the respective color lights separated by the color separation optical system 42 are incident, and liquid crystal as a hold-type light modulation device disposed at a subsequent stage of the incident-side polarizing plate 442. A panel 441 (441R, 441G, 441B), an exit-side polarizing plate 444, and a cross dichroic prism 445 as a color synthesizing optical device are provided.

  The liquid crystal panels 441R, 441G, and 441B are of an active matrix type using, for example, polysilicon TFTs as switching elements, and liquid crystal is hermetically sealed in a pair of opposed transparent substrates. Then, the liquid crystal panels 441R, 441G, and 441B modulate and emit a light beam incident through the incident side polarizing plate 442 according to image information.

The incident side polarizing plate 442 transmits only polarized light in a certain direction out of each color light separated by the color separation optical system 42 and absorbs other light beams. A polarizing film is attached to a substrate such as sapphire glass. It has been done.
The exit side polarizing plate 444 is configured in substantially the same manner as the incident side polarizing plate 442, and transmits only polarized light in a predetermined direction among the light beams emitted from the liquid crystal panels 441R, 441G, and 441B, and absorbs other light beams. The polarization axis of the polarized light to be transmitted is set so as to be orthogonal to the polarization axis of the polarized light to be transmitted by the incident side polarizing plate 442.

The cross dichroic prism 445 forms a color image by synthesizing optical images emitted from the emission-side polarizing plate 444 and modulated for each color light. The cross dichroic prism 445 is provided with a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light in a substantially X shape along the interface of four right-angle prisms. Three color lights are synthesized by the body multilayer film.
The liquid crystal panels 441R, 441G, 441B, the exit-side polarizing plate 444, and the cross dichroic prism 445 described above are integrally unitized.

(2-2. Control board structure)
As shown in FIG. 5, the control board 5 is disposed above an optical component casing (not shown). The control board 5 is configured as a circuit board on which an arithmetic processing device such as a CPU (Central Processing Unit) is mounted, and controls the entire projector 1. In addition to the light source on / off controller 51 (FIG. 7), the control board 5 is provided with a liquid crystal panel drive controller 52 (FIG. 7) for controlling the driving of the liquid crystal panel 441. The light source on / off control unit 51 performs on / off control of the light source lamps 416A and 416B provided in the light source device 411 based on a signal output from an interface board (not shown) to which the connection terminal 252 is connected. The lighting on / off control of the light source lamps 416A and 416B will be described in detail later.
Further, the control board 5 receives operation signals output from the circuit board of the operation panel 26 and the remote control light receiving module (not shown), and appropriately controls components of the projector 1 based on the operation signals. Outputs a command.

(2-3) Configuration of Power Supply Unit 6 The power supply unit 6 supplies power to the light source device 411, the control board 5, and the like, and is disposed along the longitudinal direction of the front case 23 of the exterior case 2. The power supply unit 6 includes a power supply block 61 including a power supply circuit, and a ballast 62 (FIG. 7) disposed below the power supply block 61.
The power block 61 supplies power supplied from the outside through a power cable connected to the inlet connector 22D3 to the ballast 62, the control board 5, and the like. The power supply block 61 covers a circuit board on which a transformer that converts input alternating current into low-voltage direct current, a conversion circuit that converts output from the transformer into a predetermined voltage, and the like are mounted on one side, and the circuit board. And a cylindrical member 611 as a shield member. Among these, the cylindrical member 611 is made of aluminum and is formed in a substantially box shape with both ends opened.
The ballast 62 is a conversion circuit for supplying power to the light source device 411 with a stable voltage, and the commercial alternating current input from the power supply block 61 is a light source on / off control unit provided on the control board 5. The current is rectified and converted by the ballast 62 via 51, and is supplied to the light source device 411 as a DC current or an AC rectangular wave current.

  Note that an exhaust fan 72 is installed on the side of the power supply unit 6 so that air that has cooled the power supply unit 6 is discharged from an opening in which the louver 71 is attached. A duct 73 is installed between the power supply unit 6 and the light source storage portion 48 of the light guide 45, and the air that has cooled the light source device 411 in the light source storage portion 48 is drawn by the exhaust fan 72. And is discharged from the opening through the duct 73.

(3) Light On / Off Control of Light Source Lamp FIG. 7 is a block diagram showing the light on / off control of the light source device 411 by the light source on / off controller 51.
As shown in FIG. 7, the light source on / off control unit 51 provided on the control board 5 includes the connection terminal 252 to which image information is input from the outside, the power supply block 61 of the power supply unit 6, the light source lamp 416A, 416B. Here, the connection between the light source on / off control unit 51 and the light source lamps 416A and 417A is made separately for each of the light source lamps 416A and 416B.
The light source on / off control unit 51 performs drive control of the liquid crystal panel 441 based on image information input from the connection terminal 252 and supplies light supplied from the power supply block 61 to a light source lamp 416A provided in the light source device 411. , 416B. The light source on / off control unit 51 turns on the light source lamps 416A and 416B in the intermittent lighting mode when the input image information is moving image information, and turns on the continuous lighting mode when the input image information is still image information. Turn on continuously.

Further, the control board 5 includes a liquid crystal panel drive control unit 52 and a clock circuit 53 in addition to the light source on / off control unit 51.
The liquid crystal panel drive control unit 52 is a part that performs drive control of the liquid crystal panel 441 that forms an optical image in accordance with input image information, and is connected to the light source on / off control unit 51. The liquid crystal panel drive control unit 52 drives the liquid crystal panel 441 with a frame frequency of 30 Hz in accordance with input image information.
The clock circuit 53 is a circuit that outputs a clock signal to the light source on / off control unit 51 and the liquid crystal panel drive control unit 52. The clock circuit 53 outputs a clock signal to the light source on / off control unit 51 and the liquid crystal panel drive control unit 52, and the lighting timing of the light source lamps 416A and 416B by the light source on / off control unit 51 when displaying a moving image, and the liquid crystal panel drive The frame switching timing of the liquid crystal panel 441 by the control unit 52 is synchronized.

FIG. 8 is a graph showing the light emission periods of the light source lamps 416A and 416B during moving image display. 8A and 8B show the light emission periods of the light source lamps 416A and 416B, respectively.
In the intermittent lighting mode, the light source lamps 416A and 416B have a light emission frequency set to 30 Hz as described above. The light emission periods of the respective light source lamps 416A and 416B are set so as to be shifted by 60 Hz. That is, as shown in FIG. 8, the lighting cycle of the light source lamps 416A and 416B is set to 1/30 second, and the light source lamp 416B has a light source lamp 416B approximately halfway from the first light emission to the next light emission. It is set to emit light. As a result, a light emission frequency of 60 Hz is realized by the two light source lamps 416A and 416B, and these light source lamps 416A and 416B emit light alternately at intervals of 1/60 seconds. Therefore, the light emission frequency of each of the light source lamps 416A and 416B is synchronized with the frame frequency 30 Hz of the frame forming the moving image formed by the liquid crystal panel 441.

  In this way, when displaying a moving image, the light source on / off control unit 51 alternately turns on and off the light source lamps 416A and 416B at a light emission frequency of 30 Hz, so that a light beam is emitted to the liquid crystal panel as intermittent illumination at a light emission frequency of 60 Hz. It is possible to suppress the afterimage and flicker of the moving image due to the tailing phenomenon. Accordingly, it is possible to improve the recognizability of the moving image to be projected.

In the graph shown in FIG. 8, the light amount W2 indicated on the vertical axis indicates the light emission amount per time when the light source lamps 416A and 416B emit light at the light emission frequency of 30 Hz. The figure shows the amount of light emitted per time when the light source lamps 416A and 416B are intermittently lit at 60 Hz. Here, the amount of power of the light source intermittently lit is expressed by the following equation.
W = J / F x f
In this equation, “W” represents the maximum lamp input power amount, “J / F” represents the lamp input power per light emission, and “f” represents the repetitive light emission frequency per second.
As shown in the above equation, if the maximum lamp input power amount is constant, the lamp input power per light emission decreases as the light emission frequency per second increases. For this reason, when comparing light source lamps having the same maximum lamp input power amount, the lamp input power input to the light source lamp decreases and the amount of light emitted from the light source lamp decreases as the emission frequency increases. For this reason, the light source lamps 416A, 416B are alternately turned on and off at a light emission frequency of 30 Hz, so that the light source lamps 416A, 416A, 416A, 416A and 416B are compared with the lamp input power when one light source lamp is turned on and off at a light emission frequency of 60 Hz. It is possible to set a high lamp input voltage for each light emission of 416B. Therefore, the light quantity of each light source lamp 416A and 416B can be improved, and the light quantity of a moving image can be improved.

  Further, by setting the light emission frequency of each of the light source lamps 416A and 416B to 30 Hz, the number of times of lighting per unit time can be reduced as compared with the case where one light source lamp is intermittently turned on at a light emission frequency of 60 Hz. Therefore, the number of light emission of the light source lamps can be suppressed and the life of each light source lamp can be extended.

  The light source device 411 includes two light source lamps 416A and 416B, and these are intermittently lit at a light emission frequency of 60 Hz, thereby realizing improvement in moving image recognition. Here, when a conventional method using a belt provided with a transmission film that transmits a light beam and a blocking film that blocks the light beam is employed as the light source of the projector, each light source lamp 416A, 416B is provided with a belt. Therefore, although it becomes difficult to install the light source device 411, such difficulty can be suppressed in the light source device 411 including the two light source lamps 416A and 416B.

Further, in the method using such a belt, the light beam emitted from the light source lamp when the blocking film moves on the optical path cannot be used for forming an optical image. When the light source lamps 416A and 416B are turned on and off, almost all of the light beams emitted from the light source lamps 416A and 416B can be used for forming an optical image. Therefore, no unnecessary light flux is generated, and the light quantity of the optical image to be projected can be improved.
Further, even if one of the light source lamps 416A and 416B is broken or damaged, the light quantity of the projected image can be secured by turning off one of the light source lamps at a light emission frequency of 30 Hz. By turning on and off at a frequency of 60 Hz, it is possible to ensure video recognition.

In addition, the light source lamps 416A and 416B are configured by a flashlight having an intermittent lighting mode in which intermittent lighting is performed at a light emission frequency of 30 Hz and a continuous lighting mode. According to this, the light source on / off control unit 51 switches the lighting method of the light source lamps 416A and 416B when the input image information is moving image information and when it is still image information. It can be performed by switching the light emission mode of 416B, that is, the intermittent lighting mode and the continuous lighting mode. Therefore, the light on / off control of the light source lamps 416A and 416B by the light source on / off control unit 51 can be simplified.
Further, when displaying a still image, the light source lamps 416A and 416B are continuously turned on, so that the light amount of the optical image projected by the light emission of the two light source lamps 416A and 416B can be improved.

(4) Modifications of Embodiments The present invention is not limited to the above-described embodiments, but includes modifications and improvements as long as the object of the present invention can be achieved.
In the above-described embodiment, the light emission frequencies of the light source lamps 416A and 416B when intermittently lit are 30 Hz, and the light is alternately lit to emit light at a light emission frequency of 60 Hz. However, the present invention is not limited to this. For example, the light emission frequency of each of the light source lamps 416A and 416B may be set to 30 Hz or higher, and the light beams may be emitted at a light emission frequency of 60 Hz or higher by alternately lighting them. As described above, in order to prevent humans from perceiving image flicker, the light emission frequency of the light source lamp is required to be 60 Hz or more. In a light source lamp that is intermittently lit, the lower the frequency, the lower the frequency. Since the amount of light emitted per hit increases, it is preferable that the respective light emission frequencies be 30 Hz, and the light emission frequency of 60 Hz be realized by alternately lighting them.

  In the above-described embodiment, the light source device 411 includes the two light source lamps 416A and 416B that are intermittently lit at a lighting frequency of 30 Hz. However, the present invention is not limited thereto, and includes more light source lamps. It is good also as a structure. That is, the number of the light source lamps is not limited as long as each has a predetermined light emission frequency and these are intermittently lit at a predetermined cycle. In addition, when it is set as the light source device provided with three or more light source lamps, since arrangement | positioning of the light source device in the projector 1 will become complicated, it is preferable to use two.

  In the above embodiment, the light source lamps 416A and 416B are flashlights that are intermittently lit at a light emission frequency of 30 Hz. However, the present invention is not limited to this, and flashlights having a light emission frequency in a predetermined range including 30 Hz are used. May be. In this case, the light source lighting / extinguishing control unit 51 may control the light source lamps 416A and 416B to intermittently light at a light emission frequency of 30 Hz by intermittently supplying power to the light source lamps 416A and 416B.

In the embodiment, the flash light is used as the light source lamps 416A and 416B. However, the present invention is not limited to this, and other light source lamps may be used. For example, a light source lamp using LEDs may be employed.
Moreover, as the light source lamps 416A and 416B, the flashlight having the intermittent lighting mode and the continuous lighting mode is adopted, but a light source lamp having only the intermittent lighting mode may be adopted. In this case, at the time of still image display, the light emission frequency of the light source lamps 416A and 416B may be set to 30 Hz or more, and the number of times of light emission per unit time may be increased as compared with the case of moving image display to continuously light up. Also in the still image display, the display may be performed in the intermittent lighting mode instead of the continuous lighting mode.

  Furthermore, depending on the optical characteristics of other light source lamps that can be employed as the flashlight and the light source lamps 416A and 416B, that is, the light emission and afterglow characteristics, a color filter may be arranged on the optical path. For example, when the afterglow characteristic of the green wavelength band is longer than the other wavelength bands among the luminous fluxes emitted from the light source lamp during intermittent lighting of the light source lamp, green coloring occurs. In this case, a color filter that suppresses transmission in the green wavelength band may be provided. Such a color filter may be appropriately arranged according to the optical characteristics of the light source lamp. The place where the color filter is arranged may be anywhere on the optical path from the light source lamp to the projection lens 3.

In the above embodiment, only an example of a projector using three liquid crystal panels has been described. However, a projector using only one liquid crystal panel, a projector using two liquid crystal panels, or four or more liquid crystal panels are used. It is also applicable to projectors that have been used.
In the above embodiment, a transmissive liquid crystal panel having a different light incident surface and light emitting surface is used. However, a reflective liquid crystal panel having the same light incident surface and light emitting surface may be used. .
Furthermore, in the above embodiment, only the example of the front type projector that performs projection from the direction of observing the screen has been described. However, the present invention provides a rear type projector that performs projection from the opposite side to the direction of observing the screen. Is also applicable.

  The present invention can be used for a projector.

The perspective view which looked at the projector which concerns on one Embodiment of this invention from the upper front side. The perspective view which looked at the projector in the said embodiment from the downward front side. The perspective view which looked at the projector in the said embodiment from the back back side. The perspective view which looked at the lower case and front case of the projector in the said embodiment from upper direction. The perspective view which shows the internal structure of the projector in the said embodiment. The schematic diagram of the optical system of the optical unit in the said embodiment. FIG. 3 is a block diagram for explaining turning on / off control of a light source lamp in the embodiment. The graph which shows the light emission period of the light source lamp in the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 3 ... Projection lens (projection optical system), 41 ... Light source device, 416A, 416B ... Light source lamp, 417A, 417B ... Reflector (reflection mirror), 441 (441R, 441G, 441B) ... Liquid crystal panel (hold type) (Light modulation device), 51...

Claims (4)

A light source device, a hold type light modulation device that modulates a light beam emitted from the light source device according to image information including a moving image to form an optical image, and a projection optical system that enlarges and projects the formed optical image; A projector comprising:
The light source device includes a plurality of light source lamps, and a reflecting mirror that is provided around each of the plurality of light source lamps and arranged so that illumination areas of light beams emitted from the plurality of light source lamps substantially overlap each other. With
A projector comprising: a light source on / off controller that turns on or off at least one of the plurality of light source lamps according to a switching timing of a frame constituting a moving image included in input image information. The projector according to claim 1, wherein
The light source on / off control unit sequentially switches on and turns on the plurality of light source lamps, and synchronizes a cycle in which all of the plurality of light source lamps are turned on with the frame switching cycle. The projector according to claim 2,
The light source device includes two light source lamps,
The light source on / off control unit sets the light emission frequency of each of the light source lamps to about 30 Hz, and sets one light emission period of the two light source lamps to be shifted by about 60 Hz with respect to the other. Characteristic projector. In the projector according to any one of claims 1 to 3,
The projector according to claim 1, wherein the light source lamp is a flashlight having an intermittent lighting mode in which the light source lamp is lit at a light emission frequency of about 30 Hz and a continuous lighting mode.

Images