JP4603250B2 - Color display device - Google Patents

Description

  The present invention relates to a color display device using a color wheel, and more particularly to a color liquid crystal display device in which the phase of color light can be easily adjusted.

  Currently, as a color liquid crystal display device using a color wheel, a color separation optical device used for a display device having a function of performing time-division color separation of white light, in particular, a projection type color that is projected and enlarged on a screen by a projection lens There is an image display device. This projection type color image display apparatus includes image information of an image display device, and color separation timing of a color filter (hereinafter referred to as a color wheel) that is configured and rotated by three or more color segments of reflection type or transmission type. A structure is provided that allows the image information to have a color composition function.

  FIG. 4 is a block diagram showing a color liquid crystal display device using a color wheel as an example of a conventional reflective projector. As shown in FIG. 4, this projector receives R (red), G (green), and B (blue) analog signals on a VGA (640 dots × 480 lines) screen from a computer, and has a display capacity of 4,000 colors. It is a reflection type projector having. Therefore, display control is performed for each of the RGB colors based on 4-bit image data.

  This color liquid crystal display device condenses white light from a lamp 1a of a white light source such as a metal haloid lamp by a first condenser lens 8a and is disposed in a minimum condensing area portion, and is one field period of a video signal. The second condenser lens 8b projects a light beam color-selected and transmitted by a color wheel (rotating color filter) 2e through which a color filter having the same color selection characteristic passes a plurality of times to a reflective display device 4c. This is a reflection type projector that projects reflected light that is light-modulated with a video signal onto a screen 7 by a projection lens 6. The rotational color filter 2e is rotationally driven by a motor 2b, and an index representing the rotational phase is detected by a sensor-5d.

  The reflective display device 4c has an optical switch type characteristic in which the reflectance is controlled to 1 or 0 by the drive input signal 9, and the brightness of the reflected light is determined by the ON / OFF time ratio of the optical switch and the human eye. Due to the afterimage phenomenon, it is expressed as an average luminance per unit time (30 to 60 milliseconds). The reflective display device 4c employed by this apparatus is a ferroelectric liquid crystal device having an all-color reflecting surface, or a DMD that controls electrostriction of the all-color reflecting surface.

  The display control device 3b performs analog / digital conversion on the RGB analog signals of the VGA screen input from the video input terminal 9, and then stores them cyclically as 4-bit color-specific digital image data, and a sensor 5d. Means for generating a timing pulse from the rotational phase detected in Step 1, means for driving the reflective display device 4 by reading out digital image data in order of color and level in accordance with the timing pulse, and rotational control for synchronizing the rotational color filter 1 with the video signal. Means for performing.

Further, the rotational color filter 2e that is driven to rotate by the motor 2b is controlled to rotate in synchronization with the input video signal, and a timing pulse is generated from the index detected by the sensor 5d, and this timing pulse is stored in the image storage means. The digital image data is read out in order of color and level, and the reflective display device 4c is driven.
The color wheel 2e of the rotary color filter has an RGB primary color filter film formed on a rotary disk. The rotating disk rotates once in one field period of the image, and the color filter film is formed corresponding to the image data bit of each color (for example, see Patent Document 1).

  Next, a simple configuration example of the color wheel 2e will be described. FIG. 5 is a block diagram showing a color liquid crystal display device using another conventional color wheel. FIGS. 6 (a) to 6 (c) show the positions of color segments and the colored light after color separation in the color wheel of FIG. FIG. 6 is a timing chart for explaining a relationship between output signals after sensor detection.

  This projection type color image display device includes a light source 1 serving as a white light source, a transmissive color wheel 2d that performs time-division color separation, a display control circuit 3a that controls the phase of image information and chromatic light, that is, color wheel rotation, and image information. A specular reflection type light modulator 4b for modulating light into image light, a sensor 5c for detecting the color component of the chromatic light transmitted through the color wheel 2d, a filter 5b having the characteristic of transmitting only the red component, and the screen 7. And a projection lens 6 for projecting.

  The white light source from the light source 1 is incident on the color wheel 2d and is time-division-separated, red light (hereinafter referred to as R light), green light (hereinafter referred to as G light), and blue light (hereinafter referred to as B light). And chromatic light of white light (hereinafter referred to as W light) is emitted. The emitted light is processed by a specular reflection type light modulation element 4b for optically modulating image information into image light, and the light modulated R light, G light, and B light image light is expanded by the projection lens 6. Projected on the screen 7. The color wheel 2d is provided with a timing mark 2f.

  The conventional color wheel 2d is configured to be aligned with the filter R, the filter G, the filter W, and the filter B in time series. In the case of the configuration example in which the chromatic light after passing through the color wheel 2d is detected, the relationship between the position of the color segment in the color wheel, the chromatic light after color separation, and the output signal after sensor detection is shown in FIG. It is shown in (c).

  In the prior art, when the filter B is switched to the filter R and when the filter G is switched to the filter W in FIG. 6A, the sensor 5c is turned from the OFF state to the ON state as shown in FIG. In other words, the result is that the HIGH level is output from the LOW level to the display control circuit 3a, and the display control circuit 3a performs signal processing such as invalidating the transient change when the color wheel 2d is switched from the filter G to the filter W. Do.

  The color wheel 2d configured to be aligned with the filter R, the filter G, the filter W, and the filter B in such a time series has a drawback that it is necessary to add dedicated signal processing. Further, in the case where the timing mark 2f is pasted on the color wheel 2d, there is a load that takes into consideration the labor and the bonding position of the pasting work.

JP 11-239359 A

  In the prior art, in FIGS. 6A to 6C, when switching from the filter B to the filter R and when switching from the filter G to the filter W, the sensor 5c is switched from the OFF state to the ON state, that is, from the LOW level to HIGH. As a result, the level is output to the display control circuit 3a. In the display control circuit 3a, signal processing is performed so as to invalidate a transient change when the color wheel 2d is switched from the filter G to the filter W.

  In such a color wheel 2d configured in a time series with the filter R, the filter G, the filter W, and the filter B, there is a drawback of adding dedicated signal processing. Further, when a timing mark is pasted on the color wheel 2d, there is a load of taking into account the labor and the bonding position of the pasting work.

  A main object of the present invention is to provide a color display device that facilitates color phase alignment, reduces dedicated signal processing in a display control circuit, reduces load, that is, improves work.

  The configuration of the color display device of the present invention includes a light source that emits light, a color wheel that includes a plurality of color segments that selectively separate light from the light source into a plurality of different predetermined color lights, and the color wheel that is emitted from the color wheel. At least a light modulation unit that modulates the emitted light, and a color light detection unit that receives a part of the light emitted from the color wheel and detects a predetermined color light, and the color light detection unit includes the light modulation unit. It arrange | positions in the position which can receive a part of incident light, It is characterized by the above-mentioned.

  In the present invention, the color wheel includes a W segment that emits light from the light source as it is, and the W segment and the first color segment that selectively separates the first color light of the color wheel are adjacent in the rotation direction of the color wheel. The color light detecting means can detect the first color light, and further comprises light guide means for guiding a part of the light emitted from the color wheel to a predetermined position. The light color light detecting means can be provided at a position for receiving the light emitted from the means.

Further, in the present invention, all of the plurality of color segments can emit different color lights, and the plurality of color segments respectively display red (R color), green (G color) and blue-red (B color). It can consist of outgoing R, G and B segments, and the color wheel can be transmissive or reflective,
In the present invention, a display control means for controlling the rotation of the color wheel and the light modulation means based on the input image information is provided, and the display control means displays a display image based on the color light detection signal of the light color detection means. A synchronization control unit that performs color synchronization control of the image can be included.

  As described above, according to the present invention, by arranging the sensor beside the specular reflection type light modulation element 4, it is possible to obtain the effect that the phase of the color components of the image information and the color component of the irradiation light after the color separation is necessarily obtained There is an effect that it is not necessary to attach a timing mark to the color wheel, and it is not necessary to consider an error in the bonding position caused by applying the timing mark. In addition, the color wheel has a structure in which segments are arranged so that red comes next to white in time series, and a sensor is placed beside the specular reflection type light modulator, so that the color wheel separates colors. The phase of the R light, G light, B light and W light and the image information in the specular reflection type light modulator can be matched.

  FIG. 1 is a block diagram of a projection type color image display apparatus for explaining the configuration of an embodiment of the present invention. Referring to FIG. 1, the projection type color image display apparatus has a color wheel 2a having a structure in which segments are arranged so that white follows red in time series. This projection type color image display device includes a light source 1 serving as a white light source, a transmission type color wheel 2a configured by four color segments of red, green, blue and white and performing time-division color separation, image information and chromatic light, that is, rotation of the color wheel. Display control circuit 3 that controls the phase, specular reflection type light modulator 4 that is an image display device for optically modulating image information into video light, and coloring that passes through the color wheel 2a to detect the rotational phase of the color wheel 2a It comprises a sensor 5a for detecting the color component of light, a filter 5b having the characteristic of transmitting only the red component, and a projection lens 6 for projecting onto the screen 7.

  According to the present embodiment, the color wheel 2a has a structure in which the color segments are arranged so that red follows white in time series, the sensor 5a is arranged beside the specular reflection type light modulator 4, and the color wheel Means having a function of detecting the rotational phase of the motor is provided.

  The white light source from the light source 1 is incident on the color wheel 2a, and chromatic light of R light, G light, B light, and W light, which is time-division separated, is emitted. The emitted light is processed by a specular reflection type light modulator 4 for optically modulating image information into image light, and the light modulated R light, G light, and B light image light is expanded by the projection lens 6. , And projected onto the screen 7.

  The sensor 5a provided in accordance with the present embodiment with respect to the light source optical path is disposed beside the specular reflection type light modulator 4, receives the same light source as the specular reflection type light modulator 4, and is placed on the front surface of the sensor 5a. It has a function of detecting a light source filtered by the arranged filter 5b.

  The detection signal is input to the display control circuit 3, and the display control circuit 3 controls the rotational phase of the color wheel 2a and the image information of the specular reflection type light modulator 4 to synthesize video light. The phases of the R, G, B, W, and image information in the specular reflection type light modulator 4 thus color-separated are synchronized, and are output from the projection lens 6 as optimum video light. .

  Next, a detailed configuration of the color wheel 2a will be described. In FIG. 1, the color wheel 2a is composed of four types of color filters, from a filter R that transmits R light, a filter G that transmits G light, a filter B that transmits B light, and a filter W that transmits W light. Become. Further, the color wheel 2 a is provided with a motor 2 b and its rotation is controlled by the display control circuit 3.

  2A to 2C show a configuration example of the color wheel 2a in the present embodiment of FIG. In FIG. 1, the rotation direction of the color wheel 2a is counterclockwise, and by arranging the color filter arrays as shown in FIG. W comes. At this time, after the filter W, the filter G and the filter B are arranged side by side, but the filter G and the filter B can be replaced. The light source 1, the specular reflection type light modulator 4, and the projection lens 6 in FIG. 1 are well known to those skilled in the art and are not directly related to the present invention, and thus detailed configurations thereof are omitted.

  Next, the operation of this embodiment will be described. The color wheel 2a having a structure in which segments are arranged so that white follows red in time series according to the present embodiment can be expressed as shown in FIG. First, when the light source optical path is transmitted through the filter B, the transmitted light is colored light having a blue component shown in FIG. 2B, and is condensed on the specular reflection type light modulator 4 and the filter 5b.

Since the filter 5b has a characteristic of transmitting only the red component, it cannot be detected by the sensor 5a, and the OFF state, that is, the LOW level is output to the display control circuit 3 as shown in FIG. . Next, when the light source optical path starts to pass from the filter B to the filter R, it becomes colored light having a blue component and a red component as shown in FIG. 2B, and is condensed on the specular reflection type light modulator 4 and the filter 5b. . At this time, since the filter 5b has a characteristic of transmitting only the red component, it is detected by the sensor 5a. As shown in FIG. 2C, the filter 5b is turned on from the OFF state, that is, the LOW level. To HIGH level is output to the display control circuit 3.
Similarly, while the light source optical path is applied to the filter R, the filter R to the filter W, and the filter W and the filter W to the filter G, the output of the sensor 5a is kept at the HIGH level. Thereafter, during the period from the filter G and the filter G to the filter B, the operation that outputs the LOW level, that is, cannot be detected by the sensor 5a, is repeated.

  From the above, the output of the sensor 5a is switched from the LOW level to the HIGH level only at the timing when the light source optical path is switched from the filter B to the filter R during one rotation of the color wheel 2a. Therefore, the display control circuit 3 can control the timing at which the output of the sensor 5 a is switched from the LOW level to the HIGH level and the image information of the specular reflection type light modulator 4. Further, the angles of the filter R, the filter G, the filter B, and the filter W are constant, and the phase at which the color wheel 2a makes one rotation and the ratio of the angle of each filter are matched by the phase switching from the filter B to the filter R. From this, the switching timing of each filter can be predicted.

  As a result, the R light, G light, B light, W light, and the phase of the image information in the specular reflection type light modulation element 4 that are color-separated by the color wheel 2a are synchronized, and are projected as optimum video light. Output from the lens 6.

  As another embodiment of the present invention, the basic operation is as described above, but the sensor 5a is not arranged beside the specular reflection type light modulator 4a, but the light source light beam which should be received by the sensor 5a originally. Is arranged such that a light flux guiding device such as a mirror is arranged to guide the light flux to the sensor 5a installed at another location. As described above, in this embodiment, there is an effect that there is no restriction on the arrangement of the sensor 5a.

  FIG. 3 shows still another embodiment of the present invention, and its basic operation and configuration are as shown in FIG. 1. However, the positional relationship between the point to be received by the sensor 5b and the specular reflection type light modulator 4a is shown. This is a configuration with features. In FIG. 3, the chromatic light switching at the upper part of the image display range 4d of the specular reflection type light modulator 4a and the chromatic light switching position of the sensor 5a detection unit are arranged so as to match. By doing in this way, in this embodiment, even when the shape of the color segment of the color wheel 2c is special, the image information and color in the specular reflection type light modulation element 4a are not attached to the color wheel 2c. The phase of the chromatic light after color separation by the wheel 2c can be adjusted.

1 is a block diagram of a color display device illustrating a first embodiment of the present invention. (A)-(c) is a timing diagram of the color part of the color wheel, its color output, and sensor output explaining the operation in the part of the color wheel 2 of FIG. FIG. 6 is a layout diagram of portions of a color wheel, a light modulator, and a sensor according to a second embodiment of the present invention. The block diagram of the color liquid crystal display device of a prior art example. The block diagram of the color display apparatus of another prior art example. (A)-(c) is a timing diagram of the color part of the color wheel, its color output, and sensor output explaining the operation in the part of the color wheel 2 of FIG.

Explanation of symbols

1 Light source
1a lamp 2a, 2c, 2d, 2e color wheel 2b motor 2f timing mark 3, 3a, 3b display control circuit 4, 4a, 4b specular reflection type light modulator 4c reflection type display device
4d Image display range 4e Light source luminous flux range 5, 5a, 5c, 5d Sensor
5b Filter 6 Projection lens 7 Screen
8a, 8b Condenser lens 9 Video input terminal

Claims (6)

Light modulation for modulating a light source for emitting light, a color wheel with four color segments to select separate four color light different in each other physician light from the light source, the light emitted from the color wheel Means and a color light detection means for detecting a part of the light emitted from the color wheel and detecting a predetermined color light, wherein the color light detection means receives a part of the light incident on the light modulation means. The four color segments emit light of different colors, and the color wheel includes a W segment that emits light from the light source as it is. The W segment and the first of the color wheel The color light detecting means detects only the first color light when the first color segment for selectively separating the color light is arranged adjacent to the rotation direction of the color wheel. Color display device according to symptoms. The light guide unit for guiding a part of the light emitted from the color wheel to a predetermined position is further provided, and the color light detection unit is provided at a position for receiving the light emitted from the light guide unit. Color display device. Said four color segments in addition to the W segment, red, respectively (R color), green (G color), and R segment emits blue (B color), in claim 1 or 2 consisting of G segment and B segment The color display device described. The color wheel, a color display device according to any one of claims 1 is a transmission 3. The color wheel, a color display device according to any one of claims 1 3 which is reflective. Display control means for controlling the rotation of the color wheel and the light modulation means based on the input image information, and the display control means controls the color synchronization of the display image based on the color light detection signal of the color light detection means color display device claimed in any one of 5, including a synchronization control unit for.

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