JP4085723B2 - Projection display device and display driving method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection display device using, for example, a reflective display element and a display driving method thereof.
[0002]
[Prior art]
Recently, a projection display device using a reflective liquid crystal display element and a reflective display element such as a micromirror element generally abbreviated as DMD (Digital Micromirror Device) has been developed and marketed.
[0003]
In order to display a color image on this type of projection display device, for example, a spectral mechanism called a color wheel in which, for example, three primary color filters of R, G, and B are arranged on the same circumference is arranged on the optical path. What is considered.
[0004]
In this projection display device, the color wheel is rotated at a constant speed, and image data corresponding to the color component is sequentially applied to the reflective display element in synchronization with the color of the color filter disposed on the projection optical path at that time. By displaying, as a result, a plurality of color component images are displayed in a time-sharing manner, so that the synthesized color image can be seen by human eyes.
[0005]
[Problems to be solved by the invention]
However, since the projection type display device always has a primary color filter in the optical path, the obtained projection image is inevitably less light than the light source.
[0006]
However, in this type of projection display device, the color reproducibility of the image is increased depending on the use situation, and the brightness of the image to be projected is often required first, and the color wheel is used. As long as such requirements are met, the amount of light from the light source must be increased, and the accompanying increase in heat and power consumption becomes a problem.
[0007]
Therefore, in addition to the color filters of the three primary colors R, G, and B, a color wheel in which transparent filters are arranged on the same circumference is used, and no image is displayed when the transparent filter is on the optical path. It is also considered that the brightness of the projected image is improved by totally transmitting the light from the light source.
[0008]
However, when such a color wheel is used, each color component of the color filter constituting the color wheel and the transparent filter are arranged on the same circumference at a fixed ratio. The balance of reproducibility is also constant.
[0009]
For this reason, it is particularly difficult to project an image in which color reproducibility is more important than image brightness, or on the contrary, color reproducibility is secondary and a bright image is to be projected anyway.
[0010]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a projection display apparatus that can flexibly respond to user requests and can arbitrarily adjust the brightness of an image. It is to provide a display driving method.
[0011]
[Means for Solving the Problems]
The invention described in claim 1 has a display area in which a plurality of pixels are arranged in a row direction and a column direction, and reflects or transmits incident light, and controls emission of light from the plurality of pixels. A display element for displaying an image, a light source system for projecting light from a light source onto the display element by a light source system lens, and a projection system for projecting light emitted from the display element by expanding a light beam by a projection system lens A filter mechanism that is provided in the light path of the light source system or the projection system and that can selectively arrange a color filter and a transparent filter in the optical path for limiting the color component of transmitted light or reflected light , The color filter and transparent filter are selected and driven cyclically, and in synchronization with this, while the color filter is selected, the display element displays an image corresponding to the color component of the selected color filter. And that duration, during the transparent filter selected in a predetermined ratio, characterized by comprising a display control means for a period and non-display period for displaying an image corresponding to the luminance component.
[0012]
With such a configuration, it is possible to project and display an image that is not only bright but also has high contrast.
[0013]
According to a second aspect of the present invention, in the first aspect of the present invention, the display control means corresponds to a plurality of display modes and corresponds to a luminance component set by the display mode set at that time. The ratio between the period during which an image is displayed and the non-display period is adjusted .
[0014]
With such a configuration, in addition to the operation of the first aspect of the present invention, an image having a necessary brightness can be selected and projected by a simple switching operation.
[0015]
According to a third aspect of the present invention, in the first aspect of the invention, the display control means is characterized in that the image corresponding to the luminance component during the selection of the transparent filter is an image corresponding to a luminance signal.
[0017]
According to a fourth aspect of the present invention, in the first aspect of the invention, the filter mechanism is a color wheel in which a color filter composed of a plurality of color components and a transparent filter are arranged on the same circumference, and a rotational drive mechanism thereof. It is characterized by becoming.
[0018]
With such a configuration, in addition to the operation of the first aspect of the present invention, the color wheel in which each color component of the color filter and the transparent filter are arranged on the same circumference at a fixed rate is provided at a constant speed. Even in the case of rotation, the necessary image brightness can be arbitrarily adjusted.
[0019]
According to a fifth aspect of the present invention, in the first aspect of the invention, the display control means selects only the transparent filter of the filter mechanism and displays the image corresponding to the luminance signal on the display element. It has a mode.
[0020]
With such a configuration, in addition to the operation of the first aspect of the invention, it is also possible to cope with a case where an image that emphasizes only brightness and that does not require color reproducibility is projected and displayed.
[0021]
The invention described in claim 6 has a display area in which a plurality of pixels are arranged in a row direction and a column direction, and reflects or transmits incident light, and controls emission of light from the plurality of pixels. A display element for displaying an image, a light source system for projecting light from a light source onto the display element by a light source system lens, and a projection system for projecting light emitted from the display element by expanding a light beam by a projection system lens And a filter mechanism that is provided in the light path of the light source system or the projection system and that can selectively arrange a color filter and a transparent filter in the light path to limit the color component of transmitted light or reflected light. a display driving method of the device, as well as cyclically selectively driving a color filter and a transparent filter of the filter arrangement, is in the color filter selection in synchronization therewith are the selected above display device And a period for displaying an image corresponding to the color components of the color filter, during the transparent filter selected in a predetermined ratio, characterized by a period and non-display period for displaying an image corresponding to the luminance component.
[0022]
With such a method, it is possible to flexibly respond to the user's request and arbitrarily adjust the brightness of the image.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a projection type reflection device using a micromirror element (DMD) and a color wheel will be described with reference to the drawings.
[0024]
In this figure, the display device 10 includes a micromirror element 11, a light source system 12 that projects light onto the micromirror element 11, and a projection system 13 that projects light emitted from the micromirror element 11 onto a screen (not shown). As a main component of the optical system.
[0025]
Each of the micromirror elements 11 is formed by a micromirror made of ultrathin metal pieces (for example, aluminum pieces) each having a vertical and horizontal width of 10 [μm] to 20 [μm]. These micromirrors have a display area arranged in the row and column directions, and the image is displayed by controlling the emission of light to the projection system 13 by individually switching the tilt of the micromirror corresponding to each pixel. To do.
[0026]
The light source system 12 includes a light source 14, a glass rod 15 disposed on the emission side of the light source 14, a light source lens system 16 that projects light emitted from the glass rod 15 onto the micromirror element 11, and the glass. The color wheel 17 is disposed between the rod 15 and the light source lens system 16.
[0027]
The light source 14 includes a light source lamp 18 that emits white light with high luminance, such as an ultra-high pressure mercury lamp, and a reflector 19 that condenses and reflects the emitted light from the light source lamp 18 toward the front of the optical path.
[0028]
The glass rod 15 is made of a transparent square bar having a cross-sectional shape that matches the shape of the display area of the micromirror element 11 or a square tube having a reflection film provided on the entire inner surface, and one end surface of the glass rod 15 is an incident end surface. The other end surface is used as the output end surface, and the transmitted light is reflected and diffused by the inner surface, so that the light quantity distribution of the output light is made uniform.
[0029]
The color wheel 17 appropriately splits the emitted light (white light) from the light source 14 by using a plurality of colors, for example, three primary color portions of R (red), G (green), and B (blue) and a transparent portion. It is provided for.
[0030]
FIG. 2 is a front view of the color wheel 17. The color wheel 17 is a circle in which R, G, B color filters 17r, 17g, 17b and a transparent filter 17t are arranged side by side on the same circumference. It consists of a plate-like rotating plate.
[0031]
The color wheel 17 rotates so that the color filters 17r, 17g, 17b and the transparent filter 17t sequentially pass behind the exit end face of the glass rod 15 in the direction of the projection light path to the micromirror element 11. The motors 20 are rotationally driven by being shifted laterally.
[0032]
Although the light source lens system 16 is represented by one lens per group in the drawing, in practice, the light source lens system 16 is configured by combining a plurality of lenses in order to reduce lens aberration. The glass wheel 15 is disposed on the emission side with the color wheel 17 interposed therebetween.
[0033]
In addition, the projection system 13 is represented by one lens in one group in the drawing similarly to the light source lens system 16, but is actually configured by combining a plurality of lenses in order to reduce lens aberration. The projection lens system 21 includes a light flux of reflected light (light reflected in the front direction by a plurality of micromirrors) emitted from the lens optical axis in the front direction of the micromirror element 11. It is arranged in front of the micromirror element 11 so as to coincide with the axis.
[0034]
The motor 20 rotates the color wheel 17 at a constant speed based on the drive control of the color wheel control unit 22 or stops the color wheel 17 at a predetermined rotation angle position.
[0035]
The color wheel control unit 22 controls driving of the motor 20 in synchronization with the timing signal given from the time division driving circuit 23.
[0036]
The time-division drive circuit 23 gives a timing signal to the color wheel control unit 22 in accordance with the display mode signal sent from the color sequence control circuit 24, while the RGB signals given from the video processing system circuit not shown here. Based on the video signal for each color component, in addition, a luminance (Y) signal for monochrome image display is generated by performing a matrix operation on each RGB video signal, and the video signal and luminance signal for each RGB color component are generated. Each image is displayed by supplying the micromirror element 11 so as to be continuous in time division.
[0037]
The color sequence control circuit 24 sends to the time-division drive circuit 23 a display mode selected at that time, specifically, a display mode signal for instructing the brightness of the image in stages.
[0038]
Next, the operation of the above embodiment will be described.
[0039]
FIG. 3 shows the correspondence between the rotational position of the color wheel 17 on the optical path of the light source system 12 and the image for each color component displayed on the micromirror element 11 by the time-division drive circuit 23. It is assumed that an image for one frame is displayed in 1/30 [second] by a total of four fields, one field for image display for each color component and one field for luminance signal for monochrome image.
[0040]
Accordingly, although the display time per field is 1/120 [second], the response speed of the micromirror element 11 is sufficiently high, and the time required for data writing is negligibly small. In order to facilitate the description, it will be assumed that almost one field, 1/120 [second], can be used as it is for image display.
[0041]
However, by rotating the color wheel 17 at a constant speed of 30 [rpm] as shown in FIG. 3A, the order of the R filter 17r, the G filter 17g, the B filter 17b, and the transparent filter 17t during one frame period. In this case, it is assumed that one rotation is performed so as to be positioned on the optical path by one field period.
[0042]
In synchronism with this, in the time division drive circuit 23, the R filter 17r displays an R image on the micromirror element 11 as shown in FIG. 3 (2) over the entire one field period on the optical path, and the subsequent G filter. As shown in FIG. 3 (3), the G image is displayed on the micromirror element 11 over one field period in which 17g is on the optical path, and the next B filter 17b is shown in FIG. As shown in 4), the B image is displayed by the micromirror element 11.
[0043]
Then, in the last one field period in one frame period in which the transparent filter 17t is on the optical path, the time division drive circuit 23 is shown in FIG. 3 (5) for the display time according to the display mode from the color sequence control circuit 24. ), A luminance (Y) image is displayed by the micromirror element 11 and the remaining time in the field is controlled collectively for all the pixels of the micromirror element 11 so that the emitted light does not reach the projection system 13. ing.
[0044]
In FIG. 5 (5), the duty ratio between the time when the luminance signal is displayed and the time when the luminance signal is not displayed is shown as 1/2. However, the duty ratio is obtained from the color sequence control circuit 24 as indicated by the arrow III in the figure. The display mode signal can be arbitrarily variably adjusted.
[0045]
In FIG. 4, it is assumed that the time for displaying the luminance image can be adjusted over 3 bits in 8 steps, and in addition to this, the luminance field is not displayed at all. This shows how the display time of the luminance image can be adjusted.
[0046]
Needless to say, when a luminance image is displayed throughout one field period shown in FIG. 4A, a bright image can be displayed over the entire frame. On the other hand, one-fourth of one frame is only black and white display by a luminance signal, and it is considered that the chromaticity as a color image when viewed with human eyes is greatly reduced.
[0047]
On the other hand, when no luminance signal is displayed during one field period shown in FIG. 4 (i) and no light is emitted to the projection system 13, the image displayed over one frame is the darkest. On the other hand, since black and white display is not performed at all by the luminance signal, the color reproducibility of the color image when viewed with human eyes is the most faithful to the RGB signal given to the time division drive circuit 23. It becomes.
[0048]
In this manner, the color components of the color filters 17r, 17g, and 17b and the transparent filter 17t are fixed by variably adjusting the time during which the brightest monochrome display based on the luminance signal is performed during one frame period. Even when the color wheel 17 arranged on the same circumference at a constant rate is rotated at a constant speed, it flexibly responds to the demands of the user of the projection display device 10 and adjusts the brightness of the image as necessary. It becomes possible to do.
[0049]
Therefore, for example, the projection display device 10 is provided with a brightness adjustment switch that can be switched by the user, and the display mode signal that the color sequence control circuit 24 outputs to the time-division drive circuit 23 is switched according to the operation state of the switch. If possible, an image having a necessary brightness can be selected and projected by a simple switching operation.
[0050]
In the above embodiment, the luminance signal generated by the time-division drive circuit 23 is displayed on the micromirror element 11 in the fourth field, which is the last field in one frame. If the white field that reflects light to the projection system 13 is projected and displayed in all the pixels of the micromirror element 11 in the fourth field, the contrast of the displayed image is as follows. Although it is lowered, a brighter image can be displayed.
[0051]
Further, as the transparent filter 17t of the color wheel 17 is fixed on the optical path of the light source system 12, the rotation of the color wheel 17 by the motor 20 is temporarily stopped. If it is given to the mirror element 11 for display, a sufficiently bright black and white image can be displayed by making full use of the amount of light emitted from the light source 14, and only the brightness is emphasized without requiring any color reproducibility. It is also possible to project projected images.
[0052]
Further, in the above embodiment, the micromirror element 11 is used as the reflective display element. However, the micromirror element 11 can be turned on / off, for example, about 50,000 times per second. The higher the driving speed, the shorter the time required for data writing. Therefore, in FIG. 3 and FIG.
[0053]
However, the present invention is not limited to the micromirror element as the reflective display element. For example, it is also possible to use a reflective liquid crystal display panel. In this case, data writing and liquid crystal material are written. It is necessary to adopt a driving method that takes into account the time until response to data.
[0054]
Furthermore, the display element is not limited to a reflective display element that forms an image when incident light is reflected, and forms and emits an image in the process of transmitting incident light, such as a transmissive liquid crystal display panel. It is also possible to use a type display element.
[0055]
In the above embodiment, the color wheel 17 is used as the spectral means for the white light source. Instead of the color wheel 17, for example, a hologram lens capable of selecting a specific wavelength light is multiplexed using a diffraction grating. There are other possible filter mechanisms, such as using an arrangement.
[0056]
In addition, the light source itself can be made to emit light by selecting light of a specific wavelength, such as an LED (light emitting diode) that emits light of each color of RGB, and the light source is specified by selectively or simultaneously emitting light. If the wavelength light or white light is obtained, the same effect can be achieved in terms of function, although the filter mechanism is not provided.
[0057]
In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.
[0058]
Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the column of the problem to be solved by the invention can be solved, and described in the column of the effect of the invention. In a case where at least one of the obtained effects can be obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0059]
【The invention's effect】
According to the first aspect of the invention, it is possible to project and display an image that is not only bright but also has high contrast.
[0060]
According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, it is possible to select and project an image having a necessary brightness by a simple switching operation.
[0062]
According to the invention described in claim 4, in addition to the operation of the invention described in claim 1, a color wheel in which each color component of the color filter and the transparent filter are arranged on the same circumference at a fixed ratio is fixed. Even when rotating at a speed, the necessary brightness of the image can be adjusted.
[0063]
According to the invention described in claim 5, in addition to the operation of the invention described in claim 1, it is also possible to cope with a case where an image that emphasizes only brightness and does not require color reproducibility is displayed.
[0064]
According to the sixth aspect of the present invention, it is possible to flexibly respond to the user's request and arbitrarily adjust the brightness of the image.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a projection display device according to an embodiment of the present invention.
FIG. 2 is a front view illustrating the configuration of the color wheel in FIG.
FIG. 3 is a timing chart showing display timing of each image corresponding to the rotational position of the color wheel according to the embodiment;
FIG. 4 is a view showing an adjustment range of a display time during a luminance (Y) image display period according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Projection type display apparatus 11 ... Micromirror element 12 ... Light source system 13 ... Projection system 14 ... Light source 15 ... Glass rod 16 ... Light source lens system 17 ... Color wheel 17b ... B filter 17g ... G filter 17r ... R filter 17t ... Transparent Filter 18 ... Light source lamp 19 ... Reflector 20 ... Motor 21 ... Projection lens system 22 ... Color wheel control unit 23 ... Time division drive circuit 24 ... Color sequence control circuit

Claims (6)

A display element having a display area in which a plurality of pixels are arranged in a row direction and a column direction, and reflecting or transmitting incident light and emitting the light, and controlling light emission from the plurality of pixels to display an image When,
A light source system that projects light from the light source onto the display element through a light source system lens;
A projection system for projecting the light emitted from the display element by enlarging the luminous flux by a projection system lens;
A filter mechanism provided in an optical path of the light source system or the projection system, and capable of selectively arranging a color filter and a transparent filter for limiting a color component of transmitted light or reflected light in the optical path;
The color filter and transparent filter of this filter mechanism are cyclically selected and driven, and in synchronization with this, an image corresponding to the color component of the selected color filter is displayed on the display element while the color filter is selected. A projection type comprising display control means for displaying a period corresponding to a luminance component and a non-display period at a preset ratio during the transparent filter selection. Display device. The display control means corresponds to a plurality of display modes, and adjusts a ratio of a period during which an image corresponding to the luminance component is displayed and a non-display period according to a display mode set at that time. Item 4. A projection display device according to Item 1. 2. The projection display device according to claim 1, wherein the display control means is configured such that the image corresponding to the luminance component during the selection of the transparent filter is an image corresponding to a luminance signal .   2. The reflective projection apparatus according to claim 1, wherein the filter mechanism includes a color wheel in which a color filter composed of a plurality of color components and a transparent filter are arranged on the same circumference, and a rotation drive mechanism thereof.   2. The reflective projection apparatus according to claim 1, wherein the display control means has a monochrome display mode in which only the transparent filter of the filter mechanism is selected and an image corresponding to a luminance signal is displayed on the display element. . A display element having a display area in which a plurality of pixels are arranged in a row direction and a column direction, and reflecting or transmitting incident light and emitting the light, and controlling light emission from the plurality of pixels to display an image A light source system for projecting light from a light source onto the display element by a light source system lens, a projection system for projecting light emitted from the display element by expanding a light beam by a projection system lens, and the light source system or projection system A display drive method for a projection display device, comprising a filter mechanism that is provided in the optical path and that can selectively arrange a color filter and a transparent filter for limiting the color component of transmitted light or reflected light in the optical path. ,
The color filter and transparent filter of the filter mechanism are cyclically selected and driven, and in synchronism with this, an image corresponding to the color component of the selected color filter is displayed on the display element while the color filter is selected. A display driving method for a projection display apparatus, characterized in that a period is set and a period corresponding to a luminance component is displayed and a non-display period at a preset ratio while the transparent filter is selected .

Images