JP2010276959A - Image display device - Google Patents

Abstract

In a projection-type image display device that scans three types of RGB light beams, it is possible to suppress the deviation of the image formation position of the light beams.
SOLUTION: First to third light sources 12a to 12c, a scanning mechanism 14, first to third driver circuits 16a to 16c, a signal processing unit 22, and a timing control unit 26 are provided. The first light source generates light having a first wavelength, the second light source generates light having a second wavelength, and the third light source generates light having a third wavelength. The scanning mechanism scans the light beam from each of the first to third light sources. Each of the first to third driver circuits drives the first to third light sources based on the modulation signal. The signal processing unit supplies a modulation signal to each of the first to third driver circuits based on the video signal. The timing control unit sets a timing at which the modulation signal is supplied to each of the first to third driver circuits, and the modulation signal is supplied to the first to third driver circuits based on the set timing. Control the timing.
[Selection] Figure 1

Description

  The present invention relates to an image display device.

  As the image display device, a projection-type image display device as described in Patent Documents 1 and 2 is known. Such a projection-type image display device scans the light source that generates three types of RGB light beams, an optical multiplexer that combines the light beams generated from these light sources, and the light combined by the optical multiplexer. A scanning mechanism.

JP 11-31835 A JP 2004-219514 A

  By the way, in the projection-type image display apparatus, even if the three types of RGB light beams are combined on a certain scanning position, the imaging positions of the respective light beams may be shifted. Such a shift in the imaging position of each light beam degrades the quality of the projected image.

  An object of the present invention is to provide an image display device capable of providing a high-quality image.

  The image display apparatus of the present invention includes first to third light sources, a scanning mechanism, first to third driver circuits, a signal generation unit, and a timing control unit. The first light source generates light having a first wavelength. The second light source generates light having a second wavelength. The third light source generates light having a third wavelength. The scanning mechanism scans light from the first light source, light from the second light source, and light from the third light source. The first driver circuit is a driver circuit for driving the first light source based on the modulation signal. The second driver circuit is a driver circuit for driving the second light source based on the modulation signal. The third driver circuit is a driver circuit for driving the third light source based on the modulation signal. The signal generator supplies a modulation signal to each of the first to third driver circuits based on the video signal. The timing control unit can set the timing at which the modulation signal is supplied to each of the first to third driver circuits, and the modulation signal is sent to the first to third driver circuits based on the set timing. Control the timing of supply.

  In this image display device, the timing control unit can adjust the timing at which the modulation signal is supplied to the driver circuit. Therefore, it is possible to control the light emission timing of each light source so as to compensate the positional deviation of the light of each wavelength with respect to each scanning position. As a result, the present image display apparatus can provide a high-quality image with less blur.

  The image display device of the present invention may further include a condensing lens for condensing the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength. When the image display apparatus includes a condenser lens, it is preferable that the distances between the light emission positions of the first to third light sources and the condenser lens are different so that chromatic aberration due to the condenser lens is corrected. is there. Thereby, this image display apparatus can provide an image with reduced chromatic aberration.

  The image display device combines light from the first light source, light from the second light source, and light from the third light source between the first to third light sources and the optical scanning mechanism. An optical multiplexer may be further provided. The optical multiplexer may be a planar waveguide. The optical multiplexer is optically coupled to a first incident end optically coupled to the first light source, a second incident end optically coupled to the second light source, and a third light source. And a common exit end that emits light incident on the first entrance end, light incident on the second entrance end, and light incident on the third entrance end. An optical fiber may be used.

  As described above, according to the present invention, an image display device capable of providing a high-quality image is provided.

It is a figure which shows the image display apparatus which concerns on one Embodiment. It is a figure for demonstrating the relationship between light emission timing and the imaged light. It is a figure for demonstrating the relationship between light emission timing and the imaged light. It is a figure which shows an example of an optical multiplexer. It is a figure which shows a part of image display apparatus concerning another embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a diagram illustrating an image display device according to an embodiment. An image display device 10 shown in FIG. 1 is a projection-type image display device. The image display device 10 includes a first light source 12a, a second light source 12b, a third light source 12c, a scanning mechanism 14, a first driver circuit 16a, a second driver circuit 16b, a third driver circuit 16c, and A timing control unit 18 is provided. The image display apparatus 10 of the present embodiment may further include an optical multiplexer 20 and a signal processing unit 22.

  The first light source 12a generates light having a first wavelength. The second light source 12b generates light having a second wavelength. The third light source 12a generates light having a third wavelength. In the following description, it is assumed that the first wavelength light is red (R) light, the second wavelength light is green (G) light, and the third wavelength light is blue (B) light. In addition, as a 1st-3rd light source, the light source containing a light emitting diode (LED) and a laser diode (LD) can be used, for example. However, any light source can be used in the image display device of the present invention as long as it is a light source that generates light of each of the first to third wavelengths.

  The first light source 12a is driven by the first driver circuit 16a and generates light having a first wavelength. The second light source 12b is driven by the second driver circuit 16b and generates light of the second wavelength. The third light source 12c is driven by the third driver circuit 16c and generates light of the first wavelength. Specifically, the first to third driver circuits 16a to 16c respectively supply modulation currents for modulating the light emission intensities of the first to third light sources 12a to 12c to the first to third light sources 12a to 12c. Supply.

  These first to third driver circuits 16 a to 16 c are electrically coupled to the signal processing unit 22 via the timing control unit 18. The signal processing unit 22 receives a video signal (for example, a composite video signal) at its input terminal IN, and converts the video signal into an RGB video signal. In addition, the signal processing unit 22 supplies a modulation signal based on the R component of the RGB video signal to the first driver circuit 16a. The signal processing unit 22 supplies a modulation signal based on the G component of the RGB video signal to the second driver circuit 16b. Further, the signal processing unit 22 supplies a modulation signal based on the B component of the RGB video signal to the third driver circuit 16c. Each of the first to third driver circuits 16a to 16c supplies a modulation current corresponding to the modulation signal from the signal processing unit 22 to the first to third light sources 12a to 12c.

  In the image display device 10, the timing control unit 18 controls the timing at which the modulation signal is supplied from the signal processing unit 22 to the first to third driver circuits 16 a to 16 c. The timing control unit 18 includes a first buffer circuit 24 a, a second buffer circuit 24 b, a third buffer circuit 24 c, and a timing generator 26.

  The first buffer circuit 24a is provided between the signal processing unit 22 and the first driver circuit 16a. The first buffer circuit 24a can delay the timing at which the modulated signal generated by the signal processing unit 22 is supplied to the first driver circuit 16a. The second buffer circuit 24b is provided between the signal processing unit 22 and the second driver circuit 16b. The second buffer circuit 24b can delay the timing at which the modulated signal generated by the signal processing unit 22 is supplied to the second driver circuit 16b. The third buffer circuit 24c is provided between the signal processing unit 22 and the third driver circuit 16c. The third buffer circuit 24c can delay the timing at which the modulation signal generated by the signal processing unit 22 is supplied to the third driver circuit 16c. The first to third buffer circuits 24a to 24c can be configured by delay circuits with variable delay amounts.

  The delay amount in the first to third buffer circuits 24 a to 24 c can be set by the timing generator 26. The timing generator 26 can be configured by a microcomputer, for example. In the present embodiment, the timing generator 26 has an input port 26a, a processor 26b, a memory 26c, and an output port 26d.

  The timing generator 26 can receive the input information at the input port 26a and store the input information in the memory 26c. In the present embodiment, the timing generator 26 stores the delay amount for each of the first to third buffer circuits 24a to 24c input by the light emission pattern setting device 28 such as an external computer in the memory 26c.

  Further, the timing generator 26 can provide the delay amount stored in the memory 26c to each of the first to third buffer circuits 24a to 24c via the processor 26b and the output port 26d. Accordingly, the timing generator 26 can individually adjust the timing at which the modulation signals are supplied to the first to third driver circuits 16a to 16c. As a result, the light emission timings of the first to third light sources 12a to 12c can be individually adjusted.

  In the image display device 10, the light beams from the first to third light sources 12 a to 12 c whose light emission timings are adjusted in this way are combined by the optical multiplexer 20. The scanning mechanism 14 scans the light combined by the optical multiplexer 20, that is, the light from the first light source 12a, the light from the second light source 12b, and the light from the third light source 12c, and outputs an image. Project. The scanning mechanism 14 can be constituted by, for example, a galvanometer mirror for horizontal scanning and a galvanometer mirror for vertical scanning.

  Hereinafter, the relationship between the light emission timing and the imaged light will be described with reference to FIGS. 2A shows a timing chart of three types of modulation signals (RGB modulation signals) in a conventional projection-type image display device, and FIG. 2B shows an image formed by the modulation signals. Images of each of the three wavelengths of light are shown. 3B shows an example of a timing chart of three types of modulation signals (RGB modulation signals) in the image display device 10, and FIG. 3B shows an image formed by the modulation signals. Images of each of the three wavelengths of light are shown.

  As shown in FIG. 2A, in the conventional image display device, when a white image is projected by forming three types of RGB light rays at the same position, three types of modulation signals are supplied to the driver circuit. Timing is the same. Therefore, due to poor alignment of the optical elements of the image display device, as shown in FIG. 2B, the three types of RGB rays do not combine at the same position (position centered at the point P) and are blurred. In some cases, a low-quality image is projected.

  On the other hand, in the image display device 10, even when there is a problem such as alignment failure of the optical element, the timing at which the three types of modulation signals are supplied to the first to third drivers 16a to 16c by the timing generator 26. Can be adjusted (see, for example, FIG. 3A). As a result, as shown in FIG. 3B, the image display apparatus 10 forms the three types of RGB light rays at substantially the same position (position centered at the point P) when projecting a white image. be able to. As described above, the image display apparatus 10 can project a high-quality image with reduced bleeding. Note that the timing chart shown in FIG. 3A is exemplary. Therefore, the delay amounts given to the three types of modulation signals can be arbitrarily adjusted so that the positions where the three types of RGB light rays are imaged are substantially the same.

  Hereinafter, an example of the optical multiplexer 20 described above will be described. FIG. 4 is a diagram illustrating an example of an optical multiplexer. As shown in FIG. 4, the optical multiplexer 20 may be configured by a planar optical circuit. Specifically, as shown in FIG. 4, the optical multiplexer 20 includes a first planar waveguide 20a, a second planar waveguide 20b, and a third planar waveguide 20c formed on the substrate. It is out.

  The incident end 20d of the first planar waveguide 20a is optically coupled to the first light source 12a. The incident end 20e of the second planar waveguide 20b is optically coupled to the second light source 12b. The incident end 20f of the third planar waveguide 20c is optically coupled to the third light source 12c. The light from the first light source 12a is guided by the first planar waveguide 20a, the light from the second light source 12b is guided by the second planar waveguide 20b, and the light from the third light source 12a. Is guided by the third planar waveguide 20c. Then, the light from the first light source 12a, the light from the second light source 12b, and the light from the third light source 12c are coupled to one of the planar waveguides and emitted from the emission end 20g of the planar optical circuit. Is done. Thus, a planar optical circuit may be used as the optical multiplexer 20. An optical fiber may be used instead of these planar waveguides.

  Next, an image display apparatus according to another embodiment will be described. FIG. 5 is a diagram illustrating a part of an image display apparatus according to another embodiment. An image display device 10 </ b> A illustrated in FIG. 5 includes a condenser lens 30, and the configurations of the light sources 12 a to 12 c are different from those of the image display device 10.

  The condensing lens 30 is a lens for condensing the light from the first light source 12a, the light from the second light source 12b, and the light from the third light source 12c. In this example, the condenser lens 30 is provided between the first to third light sources 12 a to 12 c and the optical multiplexer 20. The condensing lens 30 may be present between at least one of the first to third light sources 12 a to 12 c and the optical multiplexer 20 and between the optical multiplexer 20 and the scanning mechanism 14.

  In such a condenser lens, chromatic aberration occurs. In order to cope with this chromatic aberration, in the image display device 10A, the distances between the first light source 12a, the second light source 12b, and the third light source 12c and the condenser lens 30 are different from each other.

  Specifically, in the example shown in FIG. 5, the first light source 12a includes a light generator 34a that generates light of a first wavelength and an optical fiber 32a. The second light source 12b includes a light generator 34b that generates light of a second wavelength and an optical fiber 32b. The third light source 12c includes a light generator 34c that generates light of a third wavelength and an optical fiber 32c. The light generators 34a to 34c are, for example, light emitting devices such as LDs and LEDs.

  The light generator 34a is optically coupled to the optical fiber 32a, the light generator 34b is optically coupled to the optical fiber 32b, and the light generator 34c is optically coupled to the optical fiber 32c. Has been. The distance between the exit end 32d of the first optical fiber 32a and the condenser lens 30, the distance between the exit end 32e of the second optical fiber 32b and the condenser lens 30, and the third optical fiber 32c and the condenser lens 30. The distances between are different from each other so as to compensate for chromatic aberration. As described above, the image display apparatus 10 </ b> A can reduce the influence of the chromatic aberration of the condensing lens 30 by using three light sources having optical fibers whose positions of the emission ends are different from each other.

  Note that the optical fibers 32a to 32c are omitted, the light generating device 34a of the first light source 12a, the light generating device 34b of the second light source 12b, the light generating device 34c of the third light source 12c, and a condensing lens. May be set to compensate for chromatic aberration.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the optical multiplexer 20 can use various optical multiplexers such as those using a plurality of half mirrors and those using a prism.

  DESCRIPTION OF SYMBOLS 10,10A ... Image display apparatus, 12a-12c ... 1st-3rd light source, 14 ... Scanning mechanism, 16a-16c ... 1st-3rd driver circuit, 18 ... Timing control part, 20 ... Optical multiplexer, DESCRIPTION OF SYMBOLS 22 ... Signal processing part, 24a-24c ... 1st-3rd buffer circuit, 26 ... Timing generator, 28 ... Light emission pattern setting apparatus, 30 ... Condensing lens, 32a-32c ... Optical fiber.

Claims (4)

A first light source that generates light of a first wavelength;
A second light source that generates light of a second wavelength;
A third light source that generates light of a third wavelength;
A scanning mechanism that scans light from the first light source, light from the second light source, and light from the third light source;
A first driver circuit for driving the first light source based on a modulation signal;
A second driver circuit for driving the second light source based on a modulation signal;
A third driver circuit for driving the third light source based on a modulation signal;
A signal processing unit for supplying a modulation signal to each of the first to third driver circuits based on a video signal;
The timing at which the modulation signal is supplied to each of the first to third driver circuits can be set, and the modulation signal is supplied to the first to third driver circuits based on the set timing. A timing control unit for controlling the supplied timing;
An image display device comprising: A condenser lens for collecting the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength;
The distance between the light emission position of each of the first to third light sources and the condenser lens is different so as to compensate for chromatic aberration due to the condenser lens.
The image display device according to claim 1. Optical multiplexing for combining light from the first light source, light from the second light source, and light from the third light source between the first to third light sources and the scanning mechanism. Further equipped with a vessel,
The optical multiplexer is a planar waveguide;
The image display device according to claim 1. Optical multiplexing for combining light from the first light source, light from the second light source, and light from the third light source between the first to third light sources and the scanning mechanism. Further equipped with a vessel,
The optical multiplexer includes a first incident end optically coupled to the first light source, a second incident end optically coupled to the second light source, and optically coupled to the third light source. A third incident end coupled to the light source, and a common light that emits light incident on the first incident end, light incident on the second incident end, and light incident on the third incident end. An optical fiber having an emission end of
The image display device according to claim 1.

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