JP2011118038A - Illuminator and projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make uneven illuminance of a radiated image hardly cause even when a shielding amount of light from a light source is made large in order to improve a contrast ratio. <P>SOLUTION: The illuminator includes: the light source; a first polarizing part which adjusts the polarization direction of the light from the light source to a predetermined direction; and a second polarizing part which is arranged on a more downstream side in an advancing direction of emitted light from the light source than the first polarizing part, so that the light whose polarization direction is adjusted to the predetermined direction by the first polarizing part is made incident thereon, wherein the second polarizing part turns to change the polarization direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an illuminating device and a projection-type image display device provided with means for shielding the amount of light emitted from a light source by a light shielding member.

  In recent years, various means have been considered for a projection display apparatus in order to increase the brightness and improve the image quality. Among them, as one of the video qualities, a method for improving the contrast ratio defined by the brightness of the full screen white display / the brightness of the full screen black display related to the video has been proposed.

  As one means for that, Patent Document 1 discloses the following contents. That is, in Patent Document 1, a pair of fly-eye lenses including an entrance-side fly-eye lens and an exit-side fly-eye lens having a plurality of lenses are arranged, and light from a light source passes through the pair of fly-eye lenses. Thus, there is shown an illumination device and a projection display apparatus that make the light emitted from the light source uniform. The light emitted from the pair of fly-eye lenses can be shielded by operating the light-shielding plate disposed on the emission side of the pair of fly-eye lenses so that the light can be opened and closed, thereby improving the contrast ratio. it can.

JP 2003-107422 A

  In the configuration of the prior art as described above, in order to improve the contrast ratio, it is necessary to suppress the luminance at the time of full screen black display by increasing the closing amount of the light shielding plate and increasing the light shielding amount. However, when the closing amount of the light shielding plate is increased, there arises a problem that unevenness in illumination of the irradiated image is likely to occur.

  In the following, detailed contents regarding the occurrence of illuminance unevenness of the irradiated image when the closing amount of the light shielding plate is increased will be described.

  8 shows that the light emitted from a light source (not shown) is transmitted through the lens group in the right end row of the exit-side fly-eye lens 32 when viewed in the light traveling direction (arrow direction) of the optical axis L, and the light shielding plate. The figure shows that the light is partially blocked by 51 and guided to the liquid crystal panel 70. In the fly-eye lens, the incident-side fly-eye lens 31 and the emission-side fly-eye lens 32 are paired so that light passing through each minute lens constituting the fly-eye lens guides light to the entire surface of the liquid crystal panel 70. Designed. As shown in FIG. 8, since the light shielding plate 51 partially blocks the right side of the light from the lens group in the right end row of the exit side fly-eye lens 32, the light amount distribution irradiated to the liquid crystal panel 70 is as shown in FIG. The distribution is like a graph. The graph of FIG. 8 is a graph showing the light amount distribution in the horizontal direction passing through the center point on the liquid crystal panel 70. The same applies to the graphs relating to the light amount distribution in FIGS. 9 and 10.

  9 shows that the light emitted from a light source (not shown) is transmitted through the lens group in the left end row of the exit-side fly-eye lens 32 when viewed in the light traveling direction (arrow direction) of the optical axis L, and the light shielding plate. The figure shows that the light is partially blocked by 51 and guided to the liquid crystal panel 70. As shown in FIG. 9, since the light shielding plate 51 partially blocks the left side of the light from the lens group in the left end row of the emission side fly-eye lens 32, the light amount distribution irradiated to the liquid crystal panel 70 is as shown in FIG. 9. The distribution is like a graph.

  FIG. 10 is a diagram in which light emitted from a light source (not shown) is transmitted through the lens group in each column of the emission side fly-eye lens 32, and is partially blocked by the light shielding plate 51 and guided to the liquid crystal panel 70. Is shown. As illustrated in FIG. 8 and FIG. 9, the light transmitted through the lens groups in each column of the emission side fly-eye lens 32 is guided to the end of the liquid crystal panel 70 by being blocked by the light shielding plate 51. Therefore, the optical path from each lens of the exit side fly-eye lens 32 draws an optical path diagram as shown in FIG. Accordingly, the distribution of the amount of light irradiated to the liquid crystal panel 70 of the light transmitted from the lens group in each column of the emission side fly-eye lens 32 is as shown in the graph of FIG. As can be seen from the graph of FIG. 10, when the light from the emission side fly-eye lens 32 is shielded by the light shielding plate 51, unevenness in the illuminance of the light irradiated to the liquid crystal panel 70 occurs. Further, when the closing amount of the light shielding plate 51 is further increased, the light applied to the end of the liquid crystal panel 70 is further shielded, and this illuminance unevenness appears more prominently.

  In view of this, an object of the present invention is to make it difficult to generate illuminance unevenness of an irradiated image even if the amount of light shielded from a light source is increased in order to improve the contrast ratio.

Means for solving the above problems include a light source (20), a first polarization unit (for example, a polarization conversion device 40) that aligns the polarization direction of light from the light source in a specific direction, and the first polarization unit. Also, a second polarizing unit (for example, rotationally polarized light) that is disposed downstream of the light emitted from the light source and receives light whose polarization direction is aligned in a specific direction by the first polarizing unit. The lighting device (10) is characterized in that the polarization direction can be changed by rotating the plate 52) and the second polarizing section.
In the above-described means, an illumination device may further include a light-shielding portion (for example, a light-shielding plate 51) that is arranged to be openable and closable so as to shield light from the light source.
Any one of the above illumination devices, a light modulation unit (for example, liquid crystal panels 70, 71, 72, 73) that modulates light of the light source, and a projection unit (140) that enlarges and projects the light modulated by the light modulation unit It is good also as a projection type video display device provided with these.

  The projection display apparatus further includes a signal processing unit that detects brightness information of an input signal to be input and calculates brightness necessary for the projected image, and is necessary based on a calculation result of the signal processing unit. When the brightness is less than the specific light amount, the light from the light source is blocked by the light shielding unit. When the brightness required by the calculation result of the signal processing unit is equal to or greater than the specific light amount, A projection-type image display apparatus may be characterized in that a small amount of light is blocked and light of a specific light amount or more is blocked by the second polarizing unit.

  Even if the light shielding amount of the light from the light source is increased in order to improve the contrast ratio, it is possible to make it difficult to generate illuminance unevenness of the irradiated image, and it is possible to view the image without degrading the image.

It is a block diagram which shows the illuminating device 10 which concerns on embodiment. It is a block diagram which shows the light-shielding unit 50 and the output side fly eye lens 32 which concern on embodiment. It is a block diagram which shows the light-shielding unit 50 and the integrator lens 30 which rotated the rotating polarizing plate 52 which concerns on embodiment. It is a block diagram which shows the modification of the rotation polarizing plate 52 which concerns on embodiment. It is the block diagram which showed the optical structure of the projection type video display apparatus concerning embodiment. It is the block diagram which showed the internal structure of the projection type video display apparatus concerning embodiment. It is the flowchart which showed the control method of the light-shielding unit 50 which concerns on embodiment. It is a 1st block diagram which shows the structure of the light-shielding part which concerns on a prior art. It is a 2nd block diagram which shows the structure of the light-shielding part which concerns on a prior art. It is a 3rd block diagram which shows the structure of the light-shielding part which concerns on a prior art.

  Hereinafter, an illumination device and a projection display apparatus according to the present invention will be described with reference to FIGS.

  It should be noted that the drawings of the present invention are schematic diagrams, and the detailed shapes, dimensions, and ratios are different. In addition, the detailed shapes, dimensions, and ratios are different between the drawings.

  In addition, the same or similar parts are denoted by the same reference numerals with respect to different drawing numbers, and redundant description is omitted.

Further, what is shown in the present configuration diagram is an embodiment, and the present invention may be used in a different mode, and is limited to the present embodiment. It should be noted that it is not a thing (configuration of lighting device)
Below, the structure of the illuminating device which concerns on embodiment is demonstrated, referring drawings. FIG. 1 is a configuration diagram illustrating a lighting device 10 according to the embodiment.

  The light emitting unit 21 in the light source 20 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp or the like, and the irradiation light is emitted as parallel light by the parabolic reflector 22 and guided to the integrator lens 30.

  The integrator lens 30 is composed of a pair of lens groups (an incident-side fly-eye lens 31 and an emission-side fly-eye lens 32), and each lens portion emits light emitted from the light source 20 on the entire surface of a liquid crystal panel 70 to be described later. In this way, partial illuminance unevenness existing in the light source 20 is averaged, and the light amount difference between the center of the screen and the peripheral portion is reduced. The light that has passed through the integrator lens 30 is guided to the polarization conversion device 40.

  The polarization conversion device 40 is configured by a polarization beam splitter array (hereinafter referred to as a PBS array). The PBS array includes a polarization separation film and a phase difference plate (1 / 2λ plate). Each polarization separation film of the PBS array passes, for example, P-polarized light out of the light from the integrator lens 30, and changes the optical path of S-polarized light by 90 degrees. The S-polarized light whose optical path has been changed is reflected by the adjacent polarization separation film and emitted as it is. On the other hand, the P-polarized light that has passed through the polarization separation film is converted into S-polarized light by the polarizing plate provided on the front side (light emission side) and emitted. That is, in this case, almost all light is converted to S-polarized light. The light that has passed through the polarization conversion device 40 is guided to the light shielding unit 50.

  The light shielding unit 50 includes a light shielding plate 51 and a rotating polarizing plate 52. The light shielding plate 51 includes a pair of light shielding members, and opens and closes in a direction orthogonal to the optical axis L1. The rotating polarizing plate 52 is configured to be rotatable about the optical axis L1. That is, the rotating polarizing plate 52 can arbitrarily determine the polarization direction by rotating. Then, the light that has passed through the light shielding unit 50 is guided to the condenser lens 60.

  The condenser lens 60 collects the light incident on the condenser lens 60 and guides it to the liquid crystal panel 70 in order to guide the light emitted from the light shielding unit 50 to the entire surface of the liquid crystal panel 70.

  The liquid crystal panel 70 includes an incident-side polarizing plate, a panel portion in which liquid crystal is sealed between a pair of glass substrates (pixel electrodes and alignment films are formed), and an output-side polarizing plate. It is a modulation unit.

Note that this lighting device is a lighting device that uses one liquid crystal panel 70. However, the present invention is not limited to this, and a three-plate illumination device using three liquid crystal panels may be used as will be described later with reference to FIG.
(Detailed configuration of shading unit)
Next, a detailed configuration relating to the light shielding unit 50 will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a configuration diagram showing in detail the configuration of the light shielding unit 50, and shows a state where the light is not blocked by the rotating polarizing plate 52.

  The light shielding plate 51 is disposed downstream of the polarization conversion device 40 with respect to the direction in which the light emitted from the light source travels, and includes a pair of light shielding members. Each light shielding member is operated by a motor (not shown) so as to be freely opened and closed in a direction orthogonal to the optical axis L1. Therefore, as the light shielding member shifts from the open state to the closed state, the amount of light that is emitted from the polarization conversion device 40 is increased, and the amount of light passing through the light shielding plate 51 is decreased.

  The rotating polarizing plate 52 has a rectangular shape and is rotated around the optical axis L1 by a motor (not shown). For example, as described above, it is assumed that almost all light is aligned in the polarization direction to S-polarized light by the polarization conversion device 40, and S-polarized light is incident on the rotating polarizing plate 52. Then, almost all the light can be transmitted from the rotating polarizing plate 52 by adjusting the polarization direction so that all the S-polarized light can be transmitted as in the rotating position of the rotating polarizing plate 52 of FIG.

  FIG. 3 is a configuration diagram showing in detail the configuration of the light shielding unit 50, and is a diagram showing a state where substantially half of the light is blocked by the rotating polarizing plate 52.

  As shown in FIG. 2, the rotating polarizing plate 52 in FIG. 3 rotates approximately 45 ° from the rotating position of the rotating polarizing plate 52 that can transmit almost all the light incident on the rotating polarizing plate 52. It shows the state that was made to. For example, as described above, it is assumed that almost all light is aligned in the polarization direction to S-polarized light by the polarization conversion device 40, and the light is incident on the rotating polarizing plate 52. Then, if the rotating polarizing plate 52 is rotated approximately 45 ° from the rotating position of the rotating polarizing plate 52 shown in FIG. 2, substantially half of the light can be transmitted from the rotating polarizing plate 52.

Similarly, if the rotating polarizing plate 52 is rotated approximately 90 ° from the rotating position of the rotating polarizing plate 52 shown in FIG. 2, almost all the light incident on the rotating polarizing plate 52 can be blocked. (Not shown)
Thus, by using the light shielding plate 51 and the rotating polarizing plate 52 in combination, the amount of light shielded by the light shielding plate 51 is reduced as compared with the case where the light shielding plate 51 alone is used. When the amount of light blocked by the light shielding plate 51 decreases, the illuminance unevenness generated by the light shielding plate 51 decreases. Therefore, when the light shielding plate 51 and the rotating polarizing plate 52 are used in combination, the illuminance unevenness of the light emitted from the illumination device is reduced as compared with the case where the light shielding plate 51 alone is used.

  Further, when the light shielding plate 51 and the rotating polarizing plate 52 are used together, the light from the light source 20 can be dispersed and shielded by the light shielding plate 51 and the rotating polarizing plate 52. The parts can be dispersed, and the deterioration of the rotating polarizing plate 52 due to heat can be alleviated.

  In addition, by using only the rotating polarizing plate 52 without using the light shielding plate 51, the light emitted from the illumination device can be compared with the case where the light shielding plate 51 and the rotating polarizing plate 52 are used together. Irradiance unevenness is further reduced.

  In the present embodiment, the rotating polarizing plate 52 is configured to be rotatable about the optical axis L1, but is not limited thereto. For example, as shown in FIG. 4, the rotating shaft L2 is parallel to the optical axis of the light source and does not pass the light beam of the light source 20, and the rotating polarizing plate is made larger than that of the present embodiment so as to pass the light beam of the light source 20. You may distribute it.

In this way, the polarization direction can be changed by rotating the rotating polarizing plate about the rotation axis L2 that does not pass the light flux of the light source 20. For example, even if there is a transmission unit that cannot transmit light for transmitting rotational power at the center of the rotational polarizing plate, it is possible to avoid blocking the light of the light source 20 unnecessarily.
(Configuration of projection display device)
Hereinafter, the configuration of the three-plate projection display apparatus according to the embodiment will be described with reference to the drawings. FIG. 5 is a configuration diagram illustrating the optical system 100 of the projection display apparatus according to the embodiment.

  The illuminating device 10 has the above-described configuration, uniformizes partial illuminance unevenness existing in the light source 20, and adjusts the amount of light necessary for video projection.

  The first dichroic mirror 110 transmits light in the red wavelength band in the light from the illumination device 10 and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band that has passed through the first dichroic mirror 110 is reflected by the total reflection mirror 111 to change the optical path. The red light reflected by the total reflection mirror 111 is optically modulated by being transmitted through a transmissive liquid crystal panel 71 for red light. On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 110 is guided to the second dichroic mirror 120.

  The second dichroic mirror 120 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 120 is guided to the transmissive liquid crystal panel 72 for green light and is modulated by being transmitted therethrough. The light in the blue wavelength band transmitted through the second dichroic mirror 120 is guided to the transmissive liquid crystal panel 73 for blue light through the total reflection mirror 112 and the total reflection mirror 113, and is transmitted therethrough for light modulation. Is done.

  The modulated light (each color video light) modulated by passing through the liquid crystal panels 71, 72, 73 is combined by the cross dichroic prism 130 to become color video light. This color image light is enlarged and projected by the projection lens 140 and displayed on a screen (not shown).

  FIG. 6 is a block diagram showing an internal configuration of the projection display apparatus according to the embodiment.

  When the projection display apparatus main body is turned on and activated, power is supplied to electrical components such as the host CPU 200 and the light source 20 arranged on the main board.

  The host CPU 200 controls signals of the light shielding unit 50, the OSD generation unit 210, the video signal processing circuit 220, the liquid crystal panels 71, 72, 73, the cooling fan 230, and the ballast power supply 240, and signals from an operation unit that transmits commands from the user. This is based on a predetermined action during operation.

  Here, OSD is an abbreviation for on screen display, and is used as a general term for displaying characters or symbols on a video screen in order to notify the user of device information and the like, and is hereinafter referred to as OSD.

  The video signal processing circuit 220 analyzes a video signal obtained by AD-converting a video signal from an input terminal to which an external device is connected by an ADC (Analog-to-Digital Converter) 250. Therefore, the video signal processing circuit 220 can calculate how much brightness is necessary when projecting a video based on the video signal. Based on this calculation result, the host CPU 200 controls the light shielding unit 50.

  A DAC (Digital-to-Analog Converter) 260 converts the output of the video signal processing circuit 220 from a digital signal to an analog signal and transmits the analog signal to the liquid crystal panels 71, 72, and 73.

  The OSD generation unit 210 generates a predetermined phrase or symbol in a situation where it is preferable to notify the user of the projection display apparatus, and transmits the generated content to the liquid crystal panels 71, 72, and 73.

  The liquid crystal panels 71, 72, 73 are imaged based on the video signal DA-converted by the DAC 260 and the OSD generated by the OSD generation unit 210 based on a command from the host CPU 200, and transmit light from the light source 20. Generate image light. The image light is enlarged and projected via a projection lens 140 on a screen (not shown).

  The ballast power supply 240 can control the power supplied to the light source 20 via the connector 270 based on a command from the host CPU 200.

  The cooling fan 230 can cool each heat generating part by sending air to each heat generating part of the projection display apparatus through a flow path (not shown).

  Thus, by using the projection-type image display device including the above-described illumination device using both the light shielding plate 51 and the rotating polarizing plate 52, light shielding is performed by the light shielding plate 51 as compared to when light shielding is performed only by the light shielding plate 51. The amount of light will decrease. When the amount of light blocked by the light shielding plate 51 decreases, the illuminance unevenness generated by the light shielding plate 51 decreases. Therefore, when the projection display apparatus is provided with the illumination device using the light plate 51 and the rotating polarizing plate 52 in combination, the illuminance of light emitted from the projection display apparatus is less than when the light shielding plate 51 is used to block light. Unevenness is reduced.

  Further, by using the projection type video display device including the above-described illumination device that uses the light shielding plate 51 and the rotating polarizing plate 52 in combination, the light from the light source 20 is blocked in order to block unnecessary light for projecting the video. Since the light can be dispersed and shielded by the light shielding plate 51 and the rotating polarizing plate 52, the heat generation part can be dispersed by the light shielding, and it is possible to cope with a high luminance light source and to extend the life of the rotating polarizing plate.

  Further, the projection type video display device including the above-described illumination device using only the rotating polarizing plate 52 without using the light shielding plate 51 is compared with the projection type video display device including the light shielding plate 51 and the rotating polarizing plate 52. Thus, the illuminance unevenness of the light emitted from the illumination device is further reduced.

  FIG. 7 is a flowchart illustrating a method for controlling the light shielding unit 50 according to the embodiment.

  First, when there is an input signal at the input terminal, the video signal processing circuit 220 analyzes the video signal and calculates the brightness necessary for video projection (step 10).

  After step 10, the brightness of the video signal calculated by the video signal processing circuit 220 is sent to the host CPU 200, and the host CPU 200 determines whether or not the light source 20 needs to be shielded from the projected image (step). 20). If the host CPU 200 determines that the light shielding adjustment is not necessary (No in Step 20), the light shielding unit does not perform the light shielding (Step 30), and then returns to Step 10 to calculate the brightness necessary for image projection. If it is determined that the light shielding adjustment is necessary in the host CPU 200 (Yes in Step 20), the host CPU 200 determines whether or not light shielding of a specific light amount or more is necessary (Step 40).

  Here, the specific light quantity can sufficiently secure the light equalization effect performed by the integrator lens 30 when the light shielding plate 51 blocks the light from the integrator lens 30 as shown in FIGS. This indicates a light shielding amount that appears prominently until the user can actually confirm the illuminance unevenness of the image projected from the projection display apparatus. In addition, the specific light quantity not only indicates the degree of uniformity of the light performed by the integrator lens 30 but also indicates the degree to which the illuminance unevenness of the image projected from the projection image display apparatus can actually be confirmed. It is also possible to give a safe value and indicate the amount of light that does not cause sufficient illuminance unevenness.

  When it is necessary to block light of a specific light amount or more in step 40 (Yes in step 40), light that is less than the specific light amount is blocked by the light blocking plate 51 (step 50).

  After step 50, the remaining light (light of a specific light amount or more) that is not shielded by the light shielding plate 51 is shielded by the rotating polarizing plate 52 rotating (step 60).

  After step 60, the video signal processing circuit 220 determines whether or not the video signal is continuously input. If the video signal is continuously input (Yes in step 70), the process returns to step 10 to continue the video signal. If there is no input (No in step 70), the process is terminated.

  When it is not necessary to adjust the brightness beyond the specific light amount in Step 40 (No in Step 40), the light from the light source 20 is blocked by the light blocking plate 51 without performing the light blocking by the rotating polarizing plate 52 (Step 80). , Go to Step 70.

  By adopting a projection display device equipped with such a control method, even if the amount of light from the light source is further increased in order to further improve the contrast ratio, it is difficult to cause uneven illumination of the irradiated image. The video can be viewed without degrading the video.

  Further, although the present embodiment has shown the projection type video display device using the transmissive liquid crystal panel, the present invention is not limited to this, and the present invention is also applied to the projection type video display device having another video light generation system. It can be applied by DMD (Digital Mirror Device) method and LCOS (Liquid Crystal on Silicon) method.

Lighting device ... 10
Light source 20
First polarization unit (polarization conversion device) 40
Light shielding part (light shielding plate) 51
Second polarizing part (rotating polarizing plate) 52
Light modulator (liquid crystal panel) 70, 71, 72, 73
Projection unit ... 140
Signal processing unit ... 220

Claims (4)

A light source;
A first polarizing section that aligns the polarization direction of light from the light source in a specific direction;
The second polarized light is incident on the second polarized light in a specific direction by the first polarized light by being arranged downstream of the first polarized light with respect to the traveling direction of the light emitted from the light source. A polarizing section;
The illuminating device characterized in that the second polarizing unit can change a polarization direction by rotating. The lighting device according to claim 1.
An illuminating device, further comprising: a light-shielding portion arranged to be openable and closable so as to shield light from the light source. An illumination device having the configuration according to claim 1;
A light modulator for modulating light of the light source;
A projection unit for enlarging and projecting the light modulated by the light modulation unit;
A projection-type image display device comprising: The projection display apparatus according to claim 3,
It further includes a signal processing unit that detects brightness information of an input signal to be input and specifies a light shielding amount necessary for image projection,
When the amount of light shielding required when performing image projection based on the calculation result of the signal processing unit is less than the specific light amount, the light from the light source is shielded by the light shielding unit,
When the amount of light shielding required when projecting an image is greater than or equal to a specific amount of light based on the calculation result of the signal processing unit, light that is less than the specific amount of light is shielded by the light shielding unit, and the light shielding unit A projection display apparatus characterized in that light that is not shielded is shielded.

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