JP3946121B2 - Projection type image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection type image display apparatus having a plurality of light sources.
[0002]
[Prior art]
A multi-lamp type projection image display device (projector) that achieves high brightness of a display image by collecting and combining light from a plurality of light sources has been put into practical use.
[0003]
Japanese Patent Laid-Open No. 2002-90877 discloses an example of a four-lamp three-plate liquid crystal projector. FIG. 1 is a plan view showing the optical system. The illuminating device 1 includes two light sources 1a and 1b arranged opposite to each other, two light sources 1c and 1d arranged opposite to each other, an optical path changing member 2 arranged between the light sources 1a and 1b, and the light sources 1c and 1d. The optical path changing member 3 is arranged.
[0004]
The light sources 1a and 1b are shifted from the light sources 1c and 1d as shown in FIG. 2A. Each light source includes an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, and the like. The irradiation light is emitted as parallel light by a parabolic reflector, and is guided to the integrator lens 4 through the optical path changing members 2 and 3. The integrator lens 4 is composed of a pair of lens groups 4a and 4b, and each lens portion guides light emitted from the light sources 1a, 1b, 1c and 1d to the entire surface of a liquid crystal light valve which will be described later. Yes. The incident state from each light source to the integrator lens 4 is as shown in FIG. The light having passed through the integrator lens 4 is guided to the first dichroic mirror 7 after passing through the polarization conversion device 5 and the condenser lens 6.
[0005]
The first dichroic mirror 7 transmits light in the red wavelength band 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 7 passes through the concave lens 8 and is reflected by the reflecting mirror 9 to change the optical path. The red light reflected by the reflection mirror 9 is light-modulated by passing through the lens 10 and the transmissive liquid crystal light valve 31 (31a, 31b, 31c) for red light.
[0006]
On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 7 is guided to the second dichroic mirror 12 through the concave lens 11. The second dichroic mirror 12 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 12 is guided to the transmissive liquid crystal light valve 32 (32a, 32b, 32c) for green light through the lens 13, and is modulated by passing therethrough. Is done. The light in the blue wavelength band that has passed through the second dichroic mirror 12 passes through the relay lens 14, the total reflection mirror 15, the relay lens 16, the total reflection mirror 17, and the relay lens 18, and is a transmissive liquid crystal light for blue light. The light is modulated by being guided to and transmitted through the bulb 33 (33a, 33b, 33c).
[0007]
The modulated light (each color image light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the dichroic prism 19 to become color image light. This color image light is enlarged and projected by the projection lens 20 and is projected and displayed on the screen 21.
[0008]
[Patent Literature]
Japanese Patent Laid-Open No. 2002-90877
[Problems to be solved by the invention]
By the way, the first dichroic mirror 7 has a characteristic of transmitting a longer wavelength at a certain wavelength and reflecting a shorter wavelength, as shown in FIGS. 3A and 3B. Furthermore, the wavelength (half-value wavelength) with a transmittance of 50% varies depending on the incident angle. That is, one of the angle at which the light from the light sources 1a and 1c is incident on the first dichroic mirror 7 and the angle at which the light from the light sources 1b and 1d is incident on the first dichroic mirror 7 are indicated by reference C in FIG. The other is indicated by the symbol B.
[0010]
Therefore, there is a difference between the color component when the light from the light sources 1a and 1c passes through the first dichroic mirror 7 and the color component when the light from the light sources 1b and 1d passes through the first dichroic mirror 7. Arise. The phenomenon described with reference to FIG. 3 causes a difference in color appearance in an image reproduced by each light source.
[0011]
Further, as shown in FIGS. 4A and 4B, the light transmittance of the liquid crystal light valves 31, 32 and 33 varies depending on the incident angle of light. Light from a certain light source enters a certain liquid crystal light valve from the right and enters a certain liquid crystal light valve from the left. In addition, light from a certain light source enters a certain liquid crystal light valve from above, and enters a certain liquid crystal light valve from below. The reverse way also occurs.
[0012]
That is, light from a certain light source for a certain liquid crystal light valve is indicated by a symbol C in FIG. 4, and light from a certain light source for a certain liquid crystal light valve is denoted by a symbol B. Become. The phenomenon described with reference to FIG. 4 is also a factor that causes a difference in color appearance in an image reproduced by each light source.
[0013]
In a state where all of the four light sources 1a, 1b, 1c, and 1d are lit with the same light amount, the difference in color viewing is canceled by canceling out the characteristics of the light sources, so that no problem occurs. However, when one light source is out of lamp and replaced with a new light source, if there is a difference in the amount of light from each light source, the canceling state collapses, and the initial adjustment state (at the time of shipment from the factory) It will make a difference.
[0014]
In view of the above circumstances, the present invention provides a projection-type image display device that can reproduce a stable color image even when there is a difference in the amount of light of one or a plurality of light sources in the case of having a plurality of light sources. For the purpose.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 is a plurality of light sources, illumination means for irradiating the entire region of the integrator lens by guiding the light emitted from each light source toward a partial region of the integrator lens, and a plurality of light beams that have passed through the integrator lens. In a projection type image display apparatus comprising color separation means for separating the color light, a light valve for modulating each color light, and a projection means for projecting light modulated by the light valve,
A means for monitoring the accumulated lighting time of each light source and holding it in the first storage means, a second storage means for storing the light quantity reduction rate information corresponding to the cumulative lighting time of the light source, and a first storage means. Means for calculating the current light quantity of each light source based on the cumulative lighting time of each light source and the light quantity reduction rate information stored in the second storage means, and the light source with the smallest light quantity at the present time among all the light sources A dimming control means for dimming and controlling other light sources individually so as to match the light amount is provided.
[0016]
According to the above configuration, for example, when one light source is out of lamp and replaced with a new light source, only the light source has a different cumulative lighting time (the cumulative lighting time is reset at the time of replacement). There is a difference in the current light amount of each light source calculated based on the decrease rate information. The dimming control means can reproduce a stable color image as in the initial adjustment state by performing dimming control of the other light sources so as to match the light amount of the light source having the smallest light amount among all the light sources.
[0017]
According to the second aspect of the present invention, a plurality of light sources, illumination means for irradiating the entire region of the integrator lens by guiding light emitted from each light source toward a partial region of the integrator lens, and a plurality of lights passing through the integrator lens In a projection type image display apparatus comprising color separation means for separating the color light, a light valve for modulating each color light, and a projection means for projecting light modulated by the light valve,
A means for monitoring the accumulated lighting time of each light source and holding it in the first storage means, a second storage means for storing the light quantity reduction rate information corresponding to the cumulative lighting time of the light source, and a first storage means. A means for calculating the current light quantity of each light source based on the cumulative lighting time of each light source and the light quantity reduction rate information stored in the second storage means; Dimming control means for dimming and controlling the other light sources individually so as to match the light amount of the light source with the smallest light amount at the present time for each set. It is characterized by having.
[0018]
According to the above-described configuration, for example, when two sets of two light sources each having a characteristic of canceling out the difference in color appearance are provided (a total of four light sources), one light source causes a lamp breakage or the like, and a new one When the light source is replaced, the cumulative lighting time differs only for that light source (the cumulative lighting time is reset at the time of replacement), so in the group including this light source, each calculated based on the light amount reduction rate information There is a difference in the current light amount of the light source. The dimming control means restores the color-offset characteristics by adjusting the light source of each light source so that it matches the light amount of the light source with the smallest light amount for each group, and restores the stable color look as in the initial adjustment state. The image can be reproduced.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 5 and 6.
[0022]
FIG. 5 shows an optical system and a lighting control system of a four-lamp three-plate liquid crystal projector according to an embodiment of the present invention. In FIG. 5, the same parts as those in FIG.
[0023]
The illuminating device 1 includes two light sources 1a and 1b arranged opposite to each other, two light sources 1c and 1d arranged opposite to each other, an optical path changing member 2 arranged between the light sources 1a and 1b, and the light sources 1c and 1d. The optical path changing member 3 is arranged.
[0024]
The light sources 1a and 1b are arranged so as to be shifted upward with respect to 1c and 1d as shown in FIG. Each light source includes an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, and the like. The irradiation light is emitted as parallel light by a parabolic reflector, and is guided to the integrator lens 4 through the optical path changing members 2 and 3.
[0025]
The integrator lens 4 is composed of a pair of lens groups 4a and 4b, and each lens portion guides light emitted from the light sources 1a, 1b, 1c and 1d to the entire surface of a liquid crystal light valve which will be described later. Yes. The light incident state from each light source to the integrator lens 4 is as shown in FIG. The light having passed through the integrator lens 4 is guided to the first dichroic mirror 7 after passing through the deflection conversion device 5 and the condenser lens 6.
[0026]
The deflection conversion device 5 is constituted by a plurality of deflection beam splitter arrays (hereinafter referred to as PBS arrays). The PBS array includes a reflection film, a polarization separation film, and a phase difference plate (1 / 2λ plate) (all not shown).
[0027]
The polarization separation film is located corresponding to the lens center of the lens group 4 b in the integrator lens 4. The PBS array passes, for example, P-polarized light out of the light from the integrator lens 4, changes the optical path of S-polarized light by 90 °, and reflects / emits it by the reflective film. The P-polarized light that has passed through the PBS array is converted into S-polarized light by the phase difference plate provided on the front side (light emitting side) and emitted. That is, almost all light is converted to S-polarized light.
[0028]
The first dichroic mirror 7 transmits light in the red wavelength band 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 7 passes through the concave lens 8 and is reflected by the reflecting mirror 9 to change the optical path. The red light reflected by the reflection mirror 9 is light-modulated by passing through the lens 10 and the transmissive liquid crystal light valve 31 for red light.
[0029]
On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 7 is guided to the second dichroic mirror 12 through the concave lens 11. The second dichroic mirror 12 transmits light in the blue wavelength band and reflects light in the green wavelength band.
[0030]
The light in the green wavelength band reflected by the second dichroic mirror 12 is guided through the lens 13 to the transmissive liquid crystal light valve 32 for green light, and is modulated by being transmitted therethrough. The light in the blue wavelength band transmitted through the second dichroic mirror 12 passes through the relay lens 14, the total reflection mirror 15, the relay lens 16, the reflection mirror 17, and the relay lens 18, and is a transmissive liquid crystal light valve for blue light. The light is modulated by being guided to 33 and transmitted therethrough.
[0031]
Each of the liquid crystal light valves 31, 32, and 33 has a panel portion 31b formed by enclosing liquid crystal between the incident side polarizing plates 31a, 32a, and 33a and a pair of glass substrates (with pixel electrodes and alignment films formed). , 32b, 33b and output side polarizing plates 31c, 32c, 33c. In this embodiment, the incident-side polarizing plates 31a, 32a, and 33a absorb P-polarized light and transmit S-polarized light.
[0032]
The modulated light (each color image light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the dichroic prism 19 to become color image light. This color image light is enlarged and projected by the projection lens 20 and is projected and displayed on the screen 21.
[0033]
The cumulative lighting time storage unit 34 monitors the cumulative lighting time of each of the light sources 1a, 1b, 1c, and 1d, and when the light source is replaced with a new light source due to a lamp burnout or the like, the user or serviceman applies to the light source. The cumulative lighting time can be reset.
[0034]
In the light quantity reduction rate information storage unit 35, light quantity reduction rate information (aging characteristic information) corresponding to the cumulative lighting time of the light source to be used is stored in advance. For example, the format may be a table format in which the cumulative lighting time and the relative light quantity (based on the light quantity in the new state) are related, or a calculation formula for obtaining the relative light quantity from the cumulative lighting time. .
[0035]
The light quantity calculation unit 36 includes cumulative lighting time information of each of the light sources 1a, 1b, 1c, and 1d monitored by the cumulative lighting time storage unit 34, and a light quantity reduction stored in advance in the light quantity reduction rate information storage unit 35. Based on the ratio information, the current light amount of each of the light sources 1a, 1b, 1c, 1d is calculated.
[0036]
The dimming control unit 37 is configured to individually supply power to the light sources 1a, 1b, 1c, and 1d, and each of the light sources 1a, 1b, 1c, and 1d calculated from the light amount calculation unit 36. Based on the current light quantity information, the power to be supplied is determined (dimming control).
[0037]
Specifically, for example, when the light source 1a is replaced with a new one due to a lamp breakage or the like, the light amount of the light source 1a is larger than that of the light sources 1b, 1c, 1d. , 1d can be smaller than the power supplied to the light, and the dimming control can be performed so that the amount of light is equal.
[0038]
Further, for example, when the lamp replacement is repeated and the light quantity of each lamp becomes a relative ratio as shown in FIG. 6, the light source 1c which is the light source with the smallest light quantity among the light sources 1a, 1b, 1c and 1d. A stable color-viewing image can be reproduced by dimming control of the other light sources 1a, 1b, and 1d so as to match the light quantity.
[0039]
In the above example, the color canceling action of each light source is not mentioned. However, the light source 1a and the light source 1d have a canceling action that cancels the difference in color viewing when the characteristics cancel each other. Similarly, the light source 1b and the light source 1c have a canceling action.
[0040]
Using this action, for example, when the light quantity of each lamp becomes a relative ratio as shown in FIG. Dimming control is performed on the light source 1a, and the light source 1b is dimmed and controlled so as to match the light amount of the light source 1c having the smaller light amount among the light source 1b and the light source 1c.
[0041]
In the above example, the four-lamp type configuration has been described, but the present invention can be applied to other multi-lamp type configurations such as a two-lamp type or a three-lamp type.
[0042]
The light emitted from each light source is applied to the integrator lens 4 by the optical path changing members (mirrors) 2 and 3. However, the integrator lens 4 may be directly applied without passing through the optical path changing member.
[0043]
Although the present invention is particularly suitable for a liquid crystal projector, one of the causes that cause a difference in color appearance in an image reproduced by each light source is an incident angle of each light source to a dichroic mirror for color separation. Therefore, if the image projection method has such a cause, it can be applied to a projection type image display apparatus that does not use liquid crystal.
[0044]
Further, although a transmissive type liquid crystal light valve is shown, the present invention can also be applied when a reflective type liquid crystal light valve is used.
[0045]
【The invention's effect】
According to the present invention, the initial adjustment state (at the time of shipment from the factory) even when there is a difference in the amount of light of each light source, such as when one or more light sources are out of lamps and replaced with new ones in a multi-lamp configuration. This makes it possible to reproduce a stable color image without changing.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a conventional four-lamp three-plate liquid crystal projector.
FIGS. 2A and 2B are explanatory views showing the arrangement relationship of light sources. FIG.
FIG. 3 (a) is a graph showing a difference in incident angle of light from a light source with respect to a dichroic mirror.
FIG. 4A is an explanatory diagram showing a difference in incident angle of light from a light source with respect to a liquid crystal light valve, and FIG. 4B shows a change in light transmittance due to a difference in incident angle. It is a graph.
FIG. 5 is an explanatory diagram showing an optical system and a lighting control system of a four-lamp three-plate liquid crystal projector according to an embodiment of the present invention.
FIG. 6 is a configuration diagram showing a relative light amount of a light source.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Illuminating device 1a, 1b, 1c, 1d Light source 5 Polarization converter 7 1st dichroic mirror 19 Dichroic prism 20 Projection lens 31, 32, 33 Liquid crystal light valve 34 Cumulative lighting time memory | storage part 35 Light quantity reduction ratio information storage part 36 Light quantity calculation Part 37 light control part

Claims (2)

A plurality of light sources, illumination means for irradiating the entire region of the integrator lens by guiding the light emitted from each light source toward a partial region of the integrator lens, color separation means for separating the light passing through the integrator lens into a plurality of color lights, In a projection-type image display device comprising a light valve for modulating each color light and a projection means for projecting light modulated by the light valve,
The means for monitoring the accumulated lighting time of each light source and holding it in the first storage means, the second storage means in which the light quantity reduction rate information corresponding to the cumulative lighting time of the light source is stored in advance, and the first storage means. Means for calculating the current light quantity of each light source based on the cumulative lighting time of each light source and the light quantity reduction rate information stored in the second storage means, and the light source with the smallest light quantity at the present time among all the light sources A projection-type image display device comprising a dimming control means for dimming and controlling other light sources individually so as to match the light amount . A plurality of light sources, illumination means for irradiating the entire region of the integrator lens by guiding the light emitted from each light source toward a partial region of the integrator lens, color separation means for separating the light passing through the integrator lens into a plurality of color lights, In a projection-type image display device comprising a light valve for modulating each color light and a projection means for projecting light modulated by the light valve,
The means for monitoring the accumulated lighting time of each light source and holding it in the first storage means, the second storage means in which the light quantity reduction rate information corresponding to the cumulative lighting time of the light source is stored in advance, and the first storage means. A means for calculating the current light quantity of each light source based on the cumulative lighting time of each light source and the light quantity reduction rate information stored in the second storage means, and a characteristic of canceling out a plurality of light sources with respect to the difference in color Dimming control means for dimming and controlling the other light sources individually so as to match the light amount of the light source with the smallest light amount at the present time for each set. A projection-type image display device comprising:

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