JP3847990B2 - Lighting method and apparatus for projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, for example, Ru der relates illumination method and a lighting device for effective projector including the image display device.
[0002]
[Prior art]
There is a display device that displays an image using a single-plate DMD (Digital Micromirror Device). FIG. 5 shows a conventional display device.
[0003]
Reference numeral 51 denotes a light source, and the light reflected by the reflector 52 enters the first focus lens 53 and is irradiated to a part of the rotating color filter 54. The rotating color filter 54 is rotated by the motor 35, and R, G, and B filter portions can be arranged with respect to the optical path. The colored light is applied to the DMD 57 via the second focus lens 56. The DMD 57 outputs video corresponding to R, G, and B in synchronization with R, G, and B light. The light from the DMD 57 is projected onto the screen 59 via the projection lens 58.
[0004]
The light source 51 always has a constant light emission luminance. The rotating color filter 54 is rotated at a rotational speed of 1 to several times in synchronization with the vertical synchronization of the video signal. The DMD 57 displays an image corresponding to each color and controls the reflection time of each pixel when each light of R, G, B is projected in synchronization with the rotation of the rotating color filter 54. The gradation is controlled.
[0005]
[Problems to be solved by the invention]
Conventional display devices have problems such as high cost, complicated structure, large power consumption, and short life.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a projector illumination device that can obtain low power consumption, long life, and high efficiency, and that can reduce the size and cost of the device.
[0007]
[Means for Solving the Problems]
The present invention provides a first substrate in which light emitting elements of green (G) and blue (B) colors are arranged two-dimensionally, and a second substrate in which light emitting elements of red (R) colors are arranged two-dimensionally. A first modulation element that spatially modulates light from the light emitting elements of the respective colors of the first and second substrates, and inputs the resultant light to a synthesis prism; and the green (G) And a means for controlling the white balance by setting the mixing ratio of each color light by setting the lighting time of the light emitting elements of blue (B) and red (R) in different time zones within one vertical period. .
[0008]
According to the above means, the light emitting element is small and has low power consumption, has durability, is small and can be realized at low cost.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0010]
FIG. 1A shows an embodiment of the present invention. A first substrate 11 is provided with a two-dimensional array of green (G) light emitting elements (LEDs) and blue (B) light emitting elements. The light emitting elements (R) are arranged on the second substrate. For example, the same number is used for each light emitting element, for example, 500. The light emitted from the light emitting element of the substrate 11 is incident on the polarization beam splitter 14, the light having a certain polarization is incident on the reflective liquid crystal panel 13, and the reflected light whose polarization is changed passes through the polarization beam splitter 14. , Enters the combining prism 15. The light emitted from the light emitting element of the second substrate 12 is incident on the polarization beam splitter 16, and then light having a certain polarization is incident on the reflective liquid crystal panel 17. The light passes through the splitter 16 and enters the combining prism 15. The synthesis prism 15 emits each incident light in the same direction. The emitted light is projected onto a screen (not shown) through the projection lens 18.
[0011]
FIG. 1B shows a state where the light emitting elements G and B are arranged on the first substrate 11, and FIG. 1C shows a light emitting element R arranged on the second substrate 12. It shows a state.
[0012]
FIG. 2 shows a timing chart for explaining the operation of the illumination device described above. In this illuminating device, the light emission time of the light emitting element for each color is divided. That is, at least the light emission time zones of the light emitting elements for the respective colors provided on the same substrate are different.
[0013]
2A and 2B show a first example of light emission time control. In one vertical period, in this example, the light emitting element R is controlled to emit light (turn on) in the entire time zone (100% of one vertical period), but the light emitting elements G and B are included in one vertical period. It is set to emit light for a period of 40% and a period of 60%.
[0014]
On the other hand, the reflective liquid crystal panels 13 and 17 corresponding to the light emitting elements of each substrate are driven so that an image corresponding to the color is formed by the liquid crystal in accordance with the time zone of the light emitting color. Therefore, a video signal corresponding to red is always supplied to the reflective liquid crystal panel 17 (FIG. 2A). On the other hand, video signals corresponding to green and blue are supplied to the reflective liquid crystal panel 13 in a time division manner (FIG. 2B).
[0015]
In the above example, the ratio of the light emission time in one vertical period of the light emitting elements R, G, and B is set to 100%, 40%, and 60% in order to achieve white balance according to the number of the above respective elements. It is not necessarily limited to this ratio.
[0016]
In the above example, on the substrate 11 side, the light emission time zones of the light emitting elements G and B are assigned as shown in FIG. 2B. However, as shown in FIG. It is possible to suppress color distortion, flicker, and the like.
[0018]
FIG. 3 shows another reference embodiment, which is not included in the scope of the present invention. This embodiment is an example in which three color light emitting elements R, G, and B are arranged on one substrate 21 . The light emitted from the light emitting element is incident on the polarization beam splitter 22, and light having a certain polarization is incident on the reflective liquid crystal panel 23, and the reflected light whose polarization has been changed passes through the polarization beam splitter 22 and is projected onto the projection lens 24. And is projected on a screen (not shown).
[0019]
The light emitting elements R, G, B are driven in a time-sharing manner, and the reflective liquid crystal panel 23 forms an image corresponding to each color according to the light emission time zone for each color. FIG. 3B shows an example when the light-emitting elements R, G, and B are time-division driven. Here, assuming that R = 500, G = 500, and B = 500 as the required amounts of the light-emitting elements and that the lighting time is R: G: B = 5: 2: 3, R, in FIG. Each period of G and B is set to 5: 2: 3.
[0020]
In the driving method of FIG. 3B, the lighting periods of the respective emission colors are continuous, but the emission periods of the same color may be further dispersed. FIG. 3C shows an example in which the red lighting times are dispersed. Even in this case, the relationship of R: G: B = 5: 2: 3 is maintained as the lighting time. Further, as shown in FIG. 3D, the lighting times of the respective emission colors may be more finely distributed. FIG. 3E shows the arrangement of the light emitting elements when the substrate 21 is viewed from the front.
[0021]
FIG. 4 shows an example of the electrical signal processing system in each of the above-described embodiments.
[0022]
The R, G, and B analog video signals and the vertical synchronization signal are supplied to the analog processing circuit 31. The video signal is input to an analog / digital (A / D) converter 32, digitized, and input to a digital processing circuit 34. The digital processing circuit 34 uses the frame memory 35 and the frequency converter 36 to independently read out the R, G, and B video signals and supplies them to the digital analog (D / A) converter 37. The output of the D / A converter 37 is supplied to the reflective liquid crystal panel 38. The frequency converter 36 converts the R, G, and B signals, respectively, based on the timing chart shown in FIG. 2 or FIG. The frame memory 35 is used to temporarily store R, G, and B signals and obtain input / output timing.
[0023]
The control circuit 39 gives a drive timing signal to the digital processing circuit 34 and other circuits in order to obtain the drive shown in FIG. 2 or FIG. Further, the timing chart shown in FIG. 2 or 3 may be arbitrarily selected.
[0024]
Further, the digital processing circuit 34 outputs timing signals for controlling the switches S1, S2, and S3 between the power source 41 and the light emitting elements 42, 43, and 44, and controls the switches S1, S2, and S3. ing.
[0025]
In the above description, the reflective liquid crystal panel is described. However, the present invention is not limited to this, and a transmissive liquid crystal panel or a DMD (digital micromirror device) may be used. The transmissive liquid crystal panel has a configuration in which a liquid crystal panel and a substrate having R, G, and B light emitting elements are stacked behind the liquid crystal panel. Even with this configuration, a small and low-cost lighting device can be provided. When the DMD is used, for example, in the configuration as shown in FIG. 5, if the light source portion is replaced with a substrate provided with R, G, B light emitting elements, lamps and rotating systems can be reduced, and the size and weight can be reduced and the cost can be reduced. Can be realized.
[0026]
In the embodiment of FIG. 1, the light emitting element R is provided on one substrate and the light emitting elements G and B are provided on one substrate. However, this is because the light emission efficiency of R is inferior to that of G and B. Although such a configuration is used in order to obtain a balance, it is needless to say that the embodiment shown in FIG. 3 may be used as long as the light emitting element has high luminous efficiency.
[0027]
【The invention's effect】
As described above, according to the present invention, low power consumption, long life, and high efficiency can be obtained, and the size and cost of the apparatus can be reduced.
[Brief description of the drawings]
FIG. 1 is a view for explaining an embodiment of the present invention.
FIG. 2 is a timing chart shown for explaining an operation example of the embodiment of FIG. 1;
FIG. 3 is a diagram for explaining another embodiment of the present invention and an example of its operation.
FIG. 4 is a diagram showing an electrical system of the apparatus of the present invention.
FIG. 5 is a diagram showing a conventional projector illumination device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11, 12 ... Board | substrate, 13, 17 ... Reflection type liquid crystal panel, 14, 16 ... Polarizing beam splitter, 15 ... Prism, 18 ... Projection lens.

Claims (4)

A first substrate on which light emitting elements of green (G) and blue (B) colors are two-dimensionally arranged;
A second substrate on which red (R) light emitting elements are two-dimensionally arranged;
First and second modulation elements that spatially modulate the respective light from the light emitting elements of the respective colors on the first and second substrates and input them to a combining prism;
By setting the lighting time of the light emitting elements of green (G), blue (B), and red (R) to different time zones within one vertical period, the mixing ratio of each color light is set and the white balance is controlled. Means,
An illumination device for a projector, comprising:   2. The projector illumination device according to claim 1, wherein the first and second modulation elements are liquid crystal panels.   2. The illumination device for a projector according to claim 1, wherein the first and second modulation elements are digital micromirror devices. Green (G) and blue (B) light emitting elements are two-dimensionally arranged on the first substrate, and red (R) light emitting elements are two-dimensionally arranged on the second substrate, The respective light from the light emitting elements of the respective colors on the first and second substrates is spatially modulated by the first and second modulating elements, input to the combining prism, and combined, and the green (G) and blue (B ), Setting the lighting time of the light emitting element of red (R) in different time zones within one vertical period, thereby setting the white light balance by setting the mixing ratio of each color light,
  An illumination method for a projector.

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