JP2005202419A - Color display device and color display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obviate the occurrence of the perception of the color breakup due to the action to be carried out by a prsenter or the eyeball motion of an observer with a color projection display device of a color sequential driving system. <P>SOLUTION: The number of revolutions is controlled by a timing generator 18 in such a manner that the repetitive frequency (frame frequency) of three color lights of a rotary color filter 12 attains ≥180 Hz, more preferably ≥250 Hz and further preferably ≥300 Hz. The timing of the color image generation in an electrooptical apparatus 14 is so set as to coincide with the generation timing of the respective color lights. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color display device and a color display method that perform time-division driving to generate a color image.

  2. Description of the Related Art In recent years, attention has been focused on color display devices that perform color display using time difference color mixing within a single dot, that is, additive color mixing using a time-division driving method. In such a color display device, since one pixel becomes one picture element, there is an advantage that a resolution three times that of a color display device that performs juxtaposed color mixing can be obtained. One of such time-division driving type color display devices is a time sequential arrangement of R (red), G (green), and B (blue) color light generated through a color filter disk that rotates light from a white light source. The DMD displays a color image by irradiating a digital micromirror device (DMD: a device such as that developed by Texas Instruments, Inc.) array and projecting the color light modulated and reflected by the DMD array on the screen. Projectors are known. In addition, there is a color liquid crystal display device in which a color light source for generating R, G, and B color lights is arranged behind a liquid crystal panel that performs black and white display.

  However, in a color display device such as a DMD projector or a color liquid crystal display device driven in a time-sharing manner as described above, the viewer perceives color separation when the viewer's eyes are chasing a target image that crosses the screen or display, for example. It has the problem that it ends up. For this reason, there is a problem that color misregistration occurs in the viewing image and display quality is deteriorated.

  Further, in the case of a projection display device that is driven in a time-sharing manner (ie, a DMD projector or a liquid crystal projector), an operation performed by a presenter located in front of the screen, for example, pointing on the screen with an indicator bar or a finger, There is a problem that the observer perceives color separation due to the movement of the vehicle across the front. For this reason, color shift occurs in the observed image, resulting in problems such as a deterioration in display quality and an observer feeling tired. It has been reported that the same perception of color misregistration also occurs in an imaging device such as an endoscope.

  In general, when viewing an image generated by a time-division-driven color display device, R (red), G (green), B ( It is known that a color band of blue light is formed, and a phenomenon in which color separation is perceived psychologically (hereinafter referred to as color breakup) occurs.

  Here, the color breakup that occurs due to the human eye movement will be described. FIG. 12 shows that when viewing an RGB original image generated by driving three-color light in time sequential order (hereinafter referred to as “color sequential order”), an RGB motion is physically generated on the retina by eye movements that occur arbitrarily or involuntarily. The mechanism by which the color band of colored light is formed is shown. In a color display device driven in a time-sharing manner, R, G, and B images having no spatial phase shift are generated by performing synchronization signal processing on each color light of RGB and the corresponding image. A person recognizes each color image of RGB as a color image equivalent to the original image by additive color mixing in a time-integral manner at a higher-order visual center. However, during actual image appreciation, a person blinks and moves his eyes consciously or consciously. At this time, each RGB image generated in a time-integral manner by color sequential driving is affected spatially by eye movement, and as shown in FIG. 12, an RGB color band is physically formed on the retina. Due to this, it is perceived as a color breakup in higher visual centers.

  Next, an ideal model (time integration type additive color mixture) of a color image generated on the retina by color sequential driving will be described with reference to FIG. 13 in comparison with an actual model (time-space integration type additive color mixture). In the figure, the vertical axis represents time and the horizontal axis represents space. This figure shows a three-frame image, but in a color image by color sequential driving, an R image, a G image, and a B image generated on the retina with a time difference uniquely determined by the frame frequency. Is a system for color synthesis at higher visual centers. Therefore, as shown on the left side of the figure, an R image, G image, and B image (for example, an AR image, an AG image, and an AB image) forming one frame are generated on the retina with a time difference uniquely determined by the frame frequency. However, it is ideal that no spatial deviation occurs. However, in actuality, as an eye movement is involved, an R image, a G image, and a B image (for example, an AR ′ image, an AG ′ image, and an AB ′ image) that form one frame as shown on the right side of FIG. A time difference that is uniquely determined by the frame frequency and a spatial displacement that is uniquely determined by the eye movement speed are simultaneously generated on the retina. This phenomenon occurs only when eye movement occurs, and does not occur when the eyeball is stationary or in a relative stationary state (for example, the state where the eye is following the movement of a fly). In addition, this occurs differently depending on the direction of the eye movement (for example, the AR ′ image, AG ′ image, AB ′ image which is the first frame on the right side of FIG. 13, and the CR ′ image which is the third frame, The CG ′ image and the CB ′ image are generated in opposite directions).

  As described above, in a time-division driving type (color sequential driving type) color display device, color generation is basically performed on the premise of time integration type additive color mixing. However, the basic ( (Ideal) is not established, and the above-mentioned psychological color break-up perception problem occurs. FIG. 14 is an explanatory diagram showing a color image generation model based on a combination of such a color sequential driving method and a visual system. As can be seen from the figure, in color image generation by the color sequential driving method, it is necessary to develop a color display device in consideration of eye movement of human factor 1 and psychological color breakup perception of human factor 2. . In particular, in a projection display device, it is a problem to suppress the occurrence of a color breakup that is perceived due to an operation performed by a presenter that makes a presentation while standing in front of the screen in consideration of such a human factor. Become.

  It has been found that such a color breakup can be prevented from being perceived by increasing the frame frequency to about 2000 Hz to 3000 Hz and reducing the time difference of the three color lights to physically narrow the width of the color band. While the current frame frequency is about 120 Hz, image generation driving and color generation driving at a high frame frequency such as 2000 Hz to 3000 Hz are practically difficult.

  The present invention has been made in consideration of the above problems, and its purpose is to perform time-division driving that does not cause color breakup perception caused by operation performed by the presenter and color breakup perception caused by eye movement. A color display device and a color display method are provided.

  The color display device of the present invention includes a color light generation unit that repeatedly generates a plurality of color lights at a predetermined frequency in a time sequence, and the plurality of color lights so as to generate an image corresponding to each of the plurality of color lights in a time sequence. And the predetermined frequency is 180 Hz or more, thereby achieving the above object.

  Preferably, the predetermined frequency is 250 Hz or more.

  More preferably, the predetermined frequency is 300 Hz or more.

  In one embodiment, the color light generation unit includes a light source and a color filter that generates the plurality of color lights from light from the light source.

  In another embodiment, the color light generation unit includes a plurality of light sources that emit different color lights, and the plurality of light sources are lit in time sequence.

  In a certain embodiment, the said image generation part is a reflection type electro-optical apparatus, The color display apparatus in any one of Claims 1-5.

  In still another embodiment, the electro-optical device is a liquid crystal device.

  In still another embodiment, the electro-optical device is a digital micromirror device.

  In still another embodiment, the image generation unit includes a transmissive electro-optical device.

  In still another embodiment, the color display device further includes a lens for projecting the image.

  The color display method of the present invention includes a color light generation step of repeatedly generating a plurality of color lights at a predetermined frequency in a time sequence, and the plurality of color lights so as to generate an image corresponding to each of the plurality of color lights in a time sequence. An image generating step for processing the predetermined frequency, wherein the predetermined frequency is 180 Hz or more, thereby achieving the above object.

  Preferably, the predetermined frequency is 250 Hz or more.

  More preferably, the predetermined frequency is 300 Hz or more.

  According to the present invention, by setting the color light repetition frequency range in which visual system color discrimination is low, color breakup caused by, for example, a presenter standing in front of the screen and an object in front of the screen is performed. It is possible to suppress or prevent perception by an observer. Furthermore, it is possible to prevent the observer from perceiving a color breakup caused by the observer's eye movement. In addition, it is possible to drive at a repetition frequency in a practical range without significantly increasing the repetition frequency of color light generation in a time-division drive type color display device. For this reason, according to the present invention, a person viewing a display image on the screen does not feel uncomfortable with the image, and there is an effect that the quality of the observation image is improved and the fatigue caused by the image observation is reduced.

Details of the color display device and the color display method of the present invention will be described based on embodiments shown in the drawings.
(Embodiment 1)
FIG. 1 shows Embodiment 1 of a color display device and a driving method of the color display device according to the present invention. As shown in the figure, the color display device 10 of this embodiment includes a light source 11 that emits white light by including each spectrum of red light, blue light, and green light, and is disposed in front of the light source 11. Corresponding to the color of the rotating color filter 12 having red, blue and green color element regions, the condensing lens 13 disposed in front of the rotating color filter 12, and the color light incident through the condensing lens 13 The color display device includes an electro-optical device 14 that generates a color image and a projection lens 15 that receives light reflected and modulated by the electro-optical device 14 and performs projection. The image is projected onto the screen 16 and displayed. The light source 11 is also provided with a reflector 11a that reflects the light source light as shown in the figure.

  An observer who sees an image projected on the screen 16 is positioned on the front side of the screen 16 if the color display device is a front projection type, and is positioned on the back side of the screen 16 if the color display device is a rear projection type. You will see the projected image. In a presentation using a color display device, a presenter (person) stands in front of the screen 16 as viewed from the observer and uses an object such as a finger or a finger bar to explain while pointing at the projection display screen. . Therefore, from the viewpoint of the observer, the operation of the presenter and the object in front of the screen 16 is performed while blocking the display screen. Conventionally, this operation has caused a color breakup phenomenon.

  One of the effects of the present invention is to solve such a conventional color breakup perception problem, and a detailed configuration thereof will be described below.

  The electro-optical device 14 includes a liquid crystal panel in which a cell cap of a DMD array or a reflective liquid crystal light valve, a ferroelectric liquid crystal panel, an antiferroelectric liquid crystal panel, a π cell mode liquid crystal panel, or a TN liquid crystal cell is set narrowly. Various modulation devices having high-speed response such as a panel and an OCB mode liquid crystal panel can be applied.

  The color display device 10 includes a drive circuit 21 that mainly includes a microprocessor 17, a timing generator 18, a frame memory 19, and a drive control circuit 20. In the color display device 10, the timing generator 18 controls the rotational drive of the rotary color filter 12 and the drive timing of the reflective electro-optical device 14 in synchronization. First, an image signal is sampled by a sampling circuit (not shown). Then, the synchronization signal in the image input signal is sent to the microprocessor 17 and the timing generator 18. At the same time, the image data in the image signal is written into the frame memory 19 at a timing controlled by the timing generator 18. White light emitted from the light source 11 is transmitted through the three-color rotating color filter 12 that rotates in synchronization with the drive timing of the electro-optical device 14 by the timing generator 18, so that red light, blue light, and green light are emitted from the light source light. Colored light is generated by sequentially separating and transmitting the light, and the reflected electro-optical device 14 is irradiated through the condenser lens 13. Each color light irradiated in this way is subjected to light modulation by the electro-optical device 14, enlarged and projected by the projection lens 15, and formed on the screen 16 to display a color image.

  For example, the previous drive from the frame memory 19 according to the read timing signal supplied from the timing generator 18 so as to synchronize with the timing when the light from the light source 11 passes through the red region of the rotating color filter 12. The red component image data stored in advance in the cycle is sequentially read, and the drive control circuit 20 that receives the image data drives each pixel of the electro-optical device 14 in accordance with the red component image data. The timing generator 18 controls the timing so as to synchronize the timing of each component under the control of the microprocessor 17. As described above, the electro-optical device 14 is a modulation element composed of a DMD or a liquid crystal panel, and pixels each having a reflection mirror and a reflection electrode are arranged in a matrix, and each pixel reflects red light. A modulation is made in accordance with this reflection, and an image of red light is generated. Therefore, the red light whose light intensity is modulated for each pixel is incident on the projection lens 15 and a red light image is projected and displayed on the screen 16.

  Next, at the timing when the light source light is transmitted through the blue region of the rotating color filter 12, the image data for blue light is read from the frame memory 19 in the same manner as in the case of red light, and the electro-optical device 14 responds accordingly. Each pixel is driven according to the image data, modulates blue light, and an image of blue light is projected and displayed on the screen 16. Next, the same applies to the timing when the light source light passes through the green region of the rotating color filter 12. In this manner, three color light images are sequentially generated by the electro-optical device 14 and are cyclically repeated, whereby a color image is displayed. In addition, the order of color light generation is not limited to this embodiment, and any order may be used.

  When the electro-optical device 14 is a DMD, the DMD modulates the amount of light incident on the projection lens 15 by changing the tilt angle of the reflection mirror in accordance with image data for each pixel. More specifically, the time width in which the light reflected by the reflecting mirror is directed to the projection lens 15 and the time width in which the reflected light is absorbed by the absorber are subjected to pulse width modulation (PWM) according to image data, and each pixel The intensity of color light can be modulated every time. In the case of DMD, the frame memory 19 can be built in the electro-optical device as SRAM, and each pixel has a pixel memory, and a reflection mirror for each pixel is built in for each pixel according to the memory contents. The drive control circuit 20 can be driven to change the angle. However, these memories and drive control circuits are arranged below the reflection mirror.

  In the case where the electro-optical device 14 is a liquid crystal panel, the liquid crystal exemplified above is sandwiched between a pair of substrates, and a pixel electrode is provided for each pixel on the reflection side substrate. By changing the effective voltage applied to the liquid crystal according to the image data, the polarization plane and the scattering degree of the incident light are changed and reflected / exited according to the change in the arrangement of the liquid crystal molecules in the liquid crystal layer. When the polarization plane is changed, incident light is incident through the polarizing element, and reflected light is guided to the projection lens 15 through the polarizing element to modulate the light intensity for each pixel. In the case of a change in light scattering (when the liquid crystal is a polymer dispersion type or the like), the light intensity is modulated for each pixel by providing a slit in front of the projection lens 15 and allowing it to pass in the same manner as DMD. Even in the case of a liquid crystal panel, a memory (frame memory 19) is provided for each pixel below the reflective pixel electrode, and a drive control circuit 20 for applying a voltage to the pixel electrode according to the memory content is built in like the DMD. can do.

  The color display device 10 of the present embodiment has a reflective electro-optical device as the electro-optical device 14, but when a liquid crystal device (liquid crystal panel) is used, a transmissive liquid crystal panel as the electro-optical device 14. A transmissive electro-optical device including the above may be included.

  In this embodiment, the rotational speed is controlled by the timing generator 18 so that the repetition frequency (frame frequency) of the three-color light of the rotating color filter 12 is 180 Hz or higher, preferably 250 Hz or higher, more preferably 300 Hz or higher. In addition, the color image generation timing in the electro-optical device 14 is set to coincide with the generation timing of each color light.

  In the present embodiment, by performing color sequential driving at a frame frequency of 180 Hz or higher, when the observer is looking at the screen 16, the presenter who stands in front of the screen 16 and makes a presentation is moved by the finger or the presenter. Even if an eye movement caused by the movement of an object such as a finger bar occurs, the perception of color breakup can be reduced or eliminated. When color sequential driving is performed at a frame frequency of 250 Hz or higher, not only the color breakup perception associated with the motion of the presenter is prevented, but also the color breakup caused by the fast eyeball movement (described later) of the observer is perceived. Can also be reduced or eliminated. In this case, it is more preferable to perform color sequential driving at a frame frequency of 300 Hz or more in consideration of individual differences in the viewer's perception.

  Here, the reason why the color breakup perception is reduced or eliminated as in this embodiment will be described based on the relationship between the frame frequency and the visual system color space frequency.

  First, the relationship between the visual color space frequency and contrast (relative sensitivity) will be described with reference to FIG. This figure is known data described in “Television” Vol. 31, No. 1, p. 31 in 1977. The horizontal axis of the graph in the figure is the color space frequency and is represented by cycle / degree (cpd). The unit (cpd) of this color space frequency indicates the number of sine waves at a viewing angle of 1 degree. If there is a 1-cycle sine wave at a viewing angle of 1 degree, it is 1 cpd, and 5 per degree of viewing. If there is a sine wave of the cycle, it is 5 cpd. Further, the vertical axis of this graph represents the contrast sensitivity in relative sensitivity (dB), and obtains a limit value at which light / dark discrimination or color discrimination cannot be performed. As shown in FIG. 2, in general, in the human visual system, the sensitivity characteristic with respect to brightness (brightness and darkness) is poor even when the spatial frequency is low or high, and the contrast sensitivity with the lightness and darkness is the highest around the middle 4 cpd. It is high. Although not shown, the cut-off frequency of the contrast sensitivity characteristic with respect to this darkness is 60 cpd. On the other hand, the sensitivity sensitivity to the color is similarly low even when the spatial frequency is low or high, and the contrast sensitivity of the color is highest around 0.4 cpd, which is an intermediate chromaticity spatial frequency. 0. 4 cpd is a result corresponding to a frame frequency of 120 Hz in calculation, and can be said to be the worst condition from the viewpoint of a color sequential driving method in consideration of human characteristics (the current projection display device has a frame frequency of 120 Hz, Color breakup is easily perceived). Although not shown, the cutoff frequency of the sensitivity characteristic for this color is 4 to 10 cpd.

  Based on the known data shown in FIG. 2, it can be seen that a color space frequency higher than 0.4 cpd needs to be provided in order to reduce or eliminate the color breakup. The present inventors preferably give a color space frequency of 0.5 cpd or higher which is higher than 0.4 cpd which is the color space frequency, so that a person or an object located in front of the screen 16 as viewed from the observer We have found that the occurrence of perceived color breakup due to movement can be reduced or eliminated. Further, preferably, by giving a color space frequency of 0.8 cpd or more which is twice 0.4 cpd, not only the prevention of the color breakup perception but also the color perceived due to the high-speed eye movement is performed. We have found that the occurrence of breakups can also be reduced or eliminated.

  Conversion between the frame frequency and the color spatial frequency (visual system spatial frequency) can be performed using the following equations (1), (2), and (3).

Ft = (3 * Ff) ⁻¹ (1)
Cba = Rv * Ft (2)
Vf = (3 * Cba) ⁻¹ (3)
Note that Ff is a frame frequency (Hz), which is a frequency for generating one frame of a color image (one color screen). Cba is a color band viewing angle (degree) formed by each color light, and is a color band width of one color light given by a viewing angle. Further, when RGB color light is used as the color band, an R band, a G band, and a B band are formed on the retina. The viewing angle is uniquely determined by the reference point (conjunction) of the eyeball and the bandwidth of one color light formed on the retina (no viewing distance dependency). Rv is an eyeball rotation speed (degree / second), which is an angular speed when the line of sight moves from one point to another. The image projected on the retina on the inner surface of the eyeball accompanying the movement of the line of sight moves at the same angular velocity (eye rotation speed). Therefore, the eyeball rotation speed and the retina movement speed (retinal velocity) are equivalent. Vf is a visual system color space frequency (cycle / degree), and represents how many cycles of the RGB color band are formed within a viewing angle of 1 degree. For example, if one RGB color band is formed in one viewing angle, one cycle / degree (cpd) is obtained, and if five color bands are formed, 5 cpd is formed. In general, this is often used as an index representing resolution, and as the bandwidth becomes narrower, color discrimination (color discrimination discrimination) and luminance discrimination (brightness shading discrimination) decrease.

  FIG. 3 is a graph showing the relationship between the frame frequency converted using the above formulas (1), (2), and (3) and the color space frequency of the visual system. In the figure, (120, 0.4) indicates the current level of the projection display device using the color sequential driving method, and is (180, 0.5) or more, preferably (250, 0. 6) or more, more preferably (300, 0.8) or more indicates the frame frequency level used in the color display device 10 of the present embodiment.

  Next, a method for obtaining the relationship between the retina moving speed (retinal velocity) and the frame frequency using the experimental apparatus shown in FIGS. 4 and 5 will be described.

  The experimental apparatus shown in FIG. 4 includes a light source 1 for emitting white light, an RGB rotation filter 2 for spectrally generating RGB three-color light from the light source light, a screen 3, and a chopper for generating a retina moving speed. And a blade 4. In this experimental apparatus, white light emitted from the light source 1 is passed through the RGB rotation filter 2 to successively generate R color light, G color light, and B color light sequentially, and these color lights are incident on the screen 3 from the back surface. To do. A spatio-temporal color band is generated by rotating the chopper blade 4 arranged in front of the screen 3. The observer fixes a predetermined point on the screen 3 from a certain distance and forms a color band on the retina. Then, psychological color breakup perception is determined by subjective evaluation. An arbitrary frame frequency can be set by making the rotational speed of the RGB rotation filter 2 variable, and an arbitrary retinal movement speed can be set by making the rotational speed of the chopper blade 4 placed in front of the screen 3 variable. be able to.

  The experimental apparatus shown in FIG. 5 includes a light source 1 and an RGB rotation filter 2 that are RGB color light generating means in the experimental apparatus shown in FIG. 4, an R light source 5R, a G light source 5G, a B light source 5B, a red light selective reflection layer, and a blue light selective reflection. In this configuration, the dichroic prism 6 is formed in an X-shaped layer, and a color sequential drive illumination system including a mirror 7 that reflects red light and blue light from the R light source 5R and B light source B toward the prism 6 side. Each light source 5 is sequentially turned on, and three-color light is sequentially incident on the screen 3 from the back surface from the dichroic prism 6. In this experimental apparatus, an arbitrary frame frequency can be set by changing the switching of lighting of the R light source 5R, the G light source 5G, and the B light source 5B. Other configurations and operations are the same as those of the experimental apparatus shown in FIG. 4 and 5 may have a configuration in which the order of colors such as RGB, RBG, and BGR is changed.

  FIG. 6 and FIG. 7 show the relationship between the retinal movement speed and the frame frequency obtained from the results obtained for two subjects using these experimental devices. FIG. 6 is a graph showing individual data, and FIG. 7 is a graph in which the average and standard deviation are obtained based on the individual data.

  As can be seen from FIG. 6 and FIG. 7, the psychological color breakup perception shows a tendency (biphasic) in which the retinal movement speed is roughly different between less than 300 deg / sec and more than 300 deg / sec, and more than 300 deg / sec. In this case, a sharp rise in the frame frequency is recognized. There are four types of eye movement: follow-up movement, intermittent movement, vergence movement, and fixation microtremor. The follow-up movement is a low-speed eye movement of about 30 to 35 deg / sec that follows a flying fly with the eyes. On the other hand, the intermittent movement is an intermittent high-speed jumping movement, and is an eye movement that complements the movement speed of the object exceeding the speed of the follower movement, which is seen in the movement of the line of sight during reading, and is 300 deg / sec. It is the above high-speed eye movement. From this, the retinal movement speed of 300 deg / sec is equivalent to intermittent movement, and it can be interpreted that it is sufficient to ensure that the frame frequency is 250 Hz or higher on the graph, but the measurement accuracy, individual differences of subjects, etc. In view of the above, it is more preferable to secure 300 Hz or more.

  8 and 9 are obtained by inversely converting the frame frequency into the visual system color discrimination threshold in the relationship between the retinal moving speed and the frame frequency obtained from the above-described experiment. Although there is no general definition of the visual system color discrimination threshold, here the frame frequency obtained from the psychological color breakup threshold perceived as a spatio-temporal characteristic in the experiment is simply the physical frequency spreading on the retina. It is defined as an inverse transform to RGB color bandwidth.

  It can be inferred from the graphs of FIGS. 8 and 9 that there are differences in the characteristics of the visual system color discrimination threshold at retinal movement speeds of 50 to 200 deg / sec, 200 to 300 deg / sec, and 300 deg / sec or more. The eye movement considered to be related to these data is, for example, a low-speed follow-up movement of about 30 to 35 deg / sec that follows a flying fly with the eye and an object that appears suddenly and intermittently at a distance. Or a high-speed intermittent motion of 300 deg / sec or more that complements the moving speed of the object exceeding the speed of the follower movement. Note that there is generally no eye movement speed of 200 deg / sec or more and less than 300 deg / sec in the eye movement speed (equivalent to the retina movement speed) of the independent variables (horizontal axis) of the data shown in FIGS. However, an eye movement speed of 200 deg / sec or more and less than 300 deg / sec is, for example, in a presentation using a projection display device or the like, when a presenter or an object that the presenter moves in front of a screen viewed from an observer of the display screen. It may be possible to perform various actions, and the object may exist as a movement that moves on the retina. When the eye movement speed is in such a range, the color sensitivity of the visual system of the person viewing the screen is low. From the above, it is presumed that the retinal movement speed affects the change of the visual system color discrimination threshold.

  In the color display device according to the first embodiment, as described above, paying attention to the retinal movement speed range (200 deg / sec or more and 300 deg / sec) in which the visual system color sensitivity is lowered, Since the corresponding frame frequency (color generation frequency) is 180 Hz or higher from FIGS. 8 and 9, even if the presenter and the object perform various actions in front of the screen, the perception of psychological color breakup is reduced or eliminated. Can be made.

  Furthermore, when the frame frequency of the color display device according to the first embodiment is a frame frequency (color generation frequency) that satisfies the maximum speed of the existing eye movement, that is, 300 Hz that is higher than 250 Hz, the color break-up described above is performed. In addition to preventing perception, it is possible to reduce or eliminate the psychological color break-up perception that occurs in the color sequential drive system.

In the color display device 10 according to the first embodiment, it is possible to suppress the occurrence of such a phenomenon that a color break-up is perceived, so that high-quality color display can be performed on the screen. Therefore, according to the first embodiment, when the image on the screen 16 is observed, the observer does not feel discomfort with the image, and a good color image with less fatigue can be displayed. In addition, since the color display device 10 of the first embodiment can perform color display with a single electro-optical device (modulation device) 14, that is, it can be applied to a single-plate projection display device, the projector can be reduced in weight, Cost reduction can be realized.
(Embodiment 2)
FIG. 10 shows Embodiment 2 of the color display device and color display method according to the present invention. In the present embodiment, the present invention is applied to a direct-view color display device including a lighting device. In this embodiment, the repetition frequency (frame frequency) of the three-color light emitted in color sequence from the back side is controlled to be 250 Hz or more, preferably 300 Hz or more, and a color image is generated by an electro-optical device as an image generation unit. Is set to coincide with the generation timing of each color light.

  As shown in FIG. 10, the color display device 100 according to the second embodiment includes an illumination light source 101 using a color switching backlight, an electro-optical device 102, the color switching backlight illumination light source 101, and an electro-optical device. And a drive circuit 103 that drives and controls the motor 102. In FIG. 10, since the illumination device is a backlight system, a transmissive electro-optical device is used. For example, a transmissive liquid crystal display device may be used.

  The configuration of the color-switching illumination light source 101 includes, for example, a red light source, a green light source, and a blue light source (not shown), and the transmissive electro-optical device 102 transmits color light emitted from these through a light guide plate (not shown), for example. The display area is uniformly irradiated.

  In addition, as each light source as an illumination light source, it is possible to apply various color light emission sources such as fluorescent tubes such as cold cathode tubes and hot cathode tubes, EL (electroluminescence) light emitting elements, and LEDs. In the case of the backlight system, the configuration in which the light source is disposed on the back surface of the electro-optical device 102 and the configuration in which the light guide plate is disposed on the back surface and the light source is disposed on the side surface is used as the illumination light source 101, and the light source light propagates through the light guide plate. For example, a configuration in which the electro-optical device 102 is illuminated from the back surface can be considered. Also, a front light system can be used instead of a backlight system, and when the electro-optical device 102 is a reflective electro-optical device, a light guide plate is disposed on the front side and an illumination light source is disposed on the side surface. Is an illumination light source 101. The structure of the reflective electro-optical device 102 is the same as that described in the first embodiment.

  As such an electro-optical device 102, a liquid crystal display device that performs monochrome display without using a color filter can be used as in the first embodiment. For example, a cell gap of a π cell mode liquid crystal panel or a TN liquid crystal cell is narrowed. Various liquid crystal display devices having high-speed response such as a set liquid crystal panel and an OCB mode liquid crystal panel can be applied.

  The drive circuit 103 includes a microprocessor 104, a timing generator 105, a frame memory 106, a drive control circuit 107, a light source switcher 108, and a light source power source 109. In the color display device 100, the timing generator 105 controls the switching timing of the light source color switcher 108 and the driving timing of the electro-optical device 102. First, the image signal is sampled by a sampling circuit (not shown), and the synchronization signal in the image input signal is sent to the microprocessor 104 and the timing generator 105. At the same time, the image data in the image signal is written into the frame memory 106 at a timing controlled by the timing generator 105. The color-switching illumination light source 101 is a light source color switcher 108 controlled by a timing generator 105 so as to be synchronized with the driving timing of each color image of the electro-optical device 102, and is not shown in the drawing. Are repeatedly lit in time sequence. In this way, the color-switching illumination light source 101 generates color light in a color sequence corresponding to the display data color and illuminates the transmissive electro-optical device 102. The color light (display light) irradiated in this way is subjected to light modulation by the transmissive electro-optical device 102 and performs color image display in color sequence.

  For example, a light source switching timing signal is supplied from the timing generator 105 to the light source color switcher 108 so that the illumination light source 101 emits red light, and power is supplied from the light source power source 109 to the selected light source. The light source turns on. The timing generator 105 supplies a read timing signal to the frame memory 106 so as to synchronize with the switching timing of the light source color switcher 108, and the red component image data stored in advance in the previous driving cycle is sequentially supplied. The drive control circuit 107 that is read and receives the image data drives each pixel of the electro-optical device 102 according to the image data for the red component. The timing generator 105 controls the timing so as to synchronize the timing of each component under the control of the microprocessor 104. As described above, the electro-optical device 102 is a modulation element made of a liquid crystal panel, and pixels having pixel electrodes are arranged in a matrix. The red light image is modulated for each pixel, and an image of red light is obtained. Has been generated. Accordingly, an image is displayed on the display screen by the red light whose light intensity is modulated for each pixel.

  Next, at the timing of turning on the green light source with the illumination light source 101, the image data for green light is read from the frame memory 106, and each pixel of the electro-optical device 102 is Driven according to the image data, the blue light is modulated, and a green light image is projected and displayed on the display screen of the electro-optical device 102. Next, the same applies to the timing when the illumination light source 101 turns on the blue light source. In this manner, three color light images are sequentially generated by the electro-optical device 102, and this is cyclically repeated, whereby a color image is displayed. In addition, the order of color light generation is not limited to this embodiment, and any order may be used.

  Here, when the electro-optical device 102 is a transmissive liquid crystal panel, the liquid crystal exemplified above is sandwiched between a pair of substrates, and the reflective substrate has a transparent pixel electrode for each pixel. By changing the effective voltage applied from the electrode to the liquid crystal layer according to the image data, the polarization plane and the scattering degree of the incident light are changed in accordance with the change in the arrangement of the liquid crystal molecules in the liquid crystal layer and emitted. When the polarization plane is changed, incident light is incident through the polarizing element, and reflected light is transmitted through the polarizing element, whereby the light intensity is modulated for each pixel and displayed. In the case of a change in light scattering (when the liquid crystal is a polymer dispersion type or the like), the light intensity is modulated for each pixel depending on the degree of scattering, so that a polarizing element is not necessary.

  In this embodiment, the transmission type electro-optical device is used. However, a color display device that generates an image using a reflection type electro-optical device including a reflective liquid crystal panel may be used. The pixel configuration in this case is the same as that described in the first embodiment. In the case of a reflective liquid crystal panel, a memory (frame memory 106) is provided for each pixel below the reflective pixel electrode, and a drive control circuit 107 for applying a voltage to the pixel electrode in accordance with the memory contents. it can.

  As described above, in the present embodiment, lighting switching control is performed by the timing generator 105 so that the repeated lighting frequency (frame frequency) of the three-color light of the illumination light source is 250 Hz or more, preferably 300 Hz or more, and the electro-optical device. The color image generation timing at 102 is set to coincide with the generation timing of each color light.

In the present embodiment, by performing color sequential driving at the frequency as described above, a color breakup is perceived even when an eye movement occurs when viewing a display screen of a display device including an electro-optical device. Can be reduced or eliminated. Therefore, a good color display image with less feeling of fatigue can be obtained without feeling uncomfortable with the color display image.
(Embodiment 3)
FIG. 11 shows a projection display device as the color display device of the present invention. The present embodiment is different from the first embodiment in that the electro-optical device 14 of the first embodiment is replaced with a transmissive electro-optical device 240. Other configurations and operations are the same as those of the first embodiment.

  The projection display apparatus 200 of the present embodiment includes a light source 201 that emits white light by including each spectrum of red light, blue light, and green light, and a red light source, a blue light source, and a blue light source disposed in front of the light source 201. A rotating color filter 202 having a green color element region, a transmissive electro-optical device 204 that is arranged in front of the rotating color filter 202 and generates a color image corresponding to the color of incident color light, and an electro-optical device 204. And a projection lens 205 that receives the light modulated and transmitted in (5) and performs projection, and the image generation color light is projected from the projection lens 205 onto the screen 206 to display an image. The light source 201 is also provided with a reflector 201a that reflects light from the light source as shown.

  As in the first embodiment, an observer who sees an image projected on the screen 16 is positioned in front of the screen 16 if the color display device is a front projection type, and if the color display device is a rear projection type. The projected image is viewed on the back of the screen 16. In a presentation using a projection display device, a presenter (person) stands in front of the screen 16 as viewed from the observer and uses an object such as a finger or a finger bar to explain while pointing at the projection display screen. Become. Therefore, from the viewpoint of the observer, the operation of the presenter and the object in front of the screen 16 is performed while blocking the display screen.

  The electro-optical device 204 includes a ferroelectric liquid crystal panel, an antiferroelectric liquid crystal panel, a π cell mode liquid crystal panel, a liquid crystal panel in which the cell gap of the TN liquid crystal cell is set narrow, and an OCB mode liquid crystal as a liquid crystal light valve. Various modulation devices having high-speed response such as a panel can be applied.

  The projection display apparatus 200 includes a drive circuit 211 that mainly includes a microprocessor 207, a timing generator 208, a frame memory 209, and a drive control circuit 210. In the projection display apparatus 200, the timing generator 208 controls the rotational driving of the rotary color filter 202 and the driving timing of the transmission type electro-optical device 204 in synchronization. First, an image signal is sampled by a sampling circuit (not shown). Then, the synchronization signal in the image input signal is sent to the microprocessor 207 and the timing generator 208. At the same time, the image data in the image signal is written into the frame memory 209 at a timing controlled by the timing generator 208. White light emitted from the light source 201 is transmitted through the three-color rotating color filter 202 that rotates in synchronization with the drive timing of the electro-optical device 204 by the timing generator 208, thereby red light, blue light, and green light from the light source light. The color light is generated by sequentially separating and transmitting the light, and the electro-optical device 204 is irradiated with each color light. Each color light irradiated in this way is light-modulated by passing through the electro-optical device 204, enlarged and projected by the projection lens 205, and imaged on the screen 206 to display a color image.

  For example, the drive from the frame memory 209 according to the read timing signal supplied from the timing generator 208 is synchronized with the timing when the light from the light source 201 passes through the red region of the rotating color filter 202. The red component image data stored in advance in the cycle is sequentially read, and the drive control circuit 210 that receives the image data drives each pixel of the electro-optical device 204 in accordance with the red component image data. The timing generator 208 performs timing control so as to synchronize the timing of each component under the control of the microprocessor 207. The electro-optical device 204 is a modulation element made up of a liquid crystal panel. Pixels are arranged in a matrix, and red light is transmitted through each pixel. Modulation is performed in accordance with this transmission, and an image of red light is generated. ing. Therefore, the red light whose light intensity is modulated for each pixel is incident on the projection lens 205 and a red light image is projected and displayed on the screen 206.

  Next, at the timing when the light source light passes through the blue region of the rotating color filter 202, the image data for blue light is read from the frame memory 209 in the same manner as in the case of red light, and the electro-optical device 204 Each pixel is driven according to the image data, modulates blue light, and an image of blue light is projected and displayed on the screen 206. Next, the same applies to the timing when the light source light passes through the green region of the rotating color filter 202. In this way, three color light images are sequentially generated by the electro-optical device 204, and this is cyclically repeated, whereby a color image is displayed. In addition, the order of color light generation is not limited to this embodiment, and any order may be used.

  In this embodiment, the rotational speed is controlled by the timing generator 208 so that the repetition frequency (frame frequency) of the three-color light of the rotating color filter 202 is 180 Hz or higher, preferably 250 Hz or higher, more preferably 300 Hz or higher. In addition, the color image generation timing in the electro-optical device 204 is set to coincide with the generation timing of each color light.

  In the present embodiment, as in the first embodiment, by performing color sequential driving at the frequency as described above, it is possible to perform a display that lowers the visual system color identification sensitivity. Even if an eye movement due to the motion of a presenter or an object located in front of the screen 206 occurs, the perception of color breakup can be reduced or eliminated. Therefore, a good presentation can be performed without feeling uncomfortable with the color display image. For this reason, in this embodiment, it is possible to obtain a good color display image that does not give the observer a feeling of fatigue.

  As mentioned above, although Embodiment 1-3 was demonstrated, this invention is not limited to these, The various change accompanying the summary of a structure is possible. In addition to the above-described embodiments, the present invention can also be applied to various color display devices such as a projection display device using a transmissive light valve and a reflection display device having a light source in front or side of the display screen. Is possible.

  Further, in the present invention, the plurality of color lights to be generated are described as the three color lights of red light, blue light, and green light. However, the three color lights of cyan light, magenta light, and yellow light may be used. It is possible to switch the color light more than the color light.

  In the first and third embodiments, the light source light from one light source that emits the light source light including a plurality of color light components (for example, red light, blue light, and green light) is transmitted through the rotating color filter (12, 202). Each color light is generated by this, but a plurality of light sources (red light source, green light source, blue light source) that individually generate a plurality of color lights as in the color sequential drive illumination system of FIG. The light sources that are turned on sequentially by the timing generators (18, 208) may be sequentially selected to generate color light. Even in such a case, the color break-up phenomenon is caused by performing timing-controlled driving of the projection display device so that the repetition frequency for generating a plurality of color lights is 180 Hz or more, preferably 250 Hz or more, and more preferably 300 Hz or more. It can be reduced or suppressed.

  The present invention provides a time-division-driven color display device and a color display method that do not cause a color breakup perception caused by an operation performed by a presenter and a color breakup perception caused by eye movement.

1 is a configuration explanatory view showing Embodiment 1 of a color display device according to the present invention. It is a graph which shows the color space frequency characteristic of vision. It is a graph which shows the relationship between a frame frequency and a visual system color space frequency. It is explanatory drawing which shows the experimental apparatus for calculating | requiring the relationship between a retina moving speed and a frame frequency. It is explanatory drawing which shows the modification of the experimental apparatus for calculating | requiring the relationship between a retina moving speed and a frame frequency. It is a graph which shows a visual system optimal frame frequency characteristic. It is a graph which shows a visual system optimal frame frequency characteristic. It is a graph which shows a visual system color discrimination threshold characteristic. It is a graph which shows a visual system color discrimination threshold characteristic. FIG. 7 is an explanatory diagram illustrating a configuration of a color display device according to a second embodiment of the present invention. FIG. 9 is an explanatory diagram illustrating a configuration of a projection display apparatus according to a third embodiment of the present invention. It is explanatory drawing which shows the mechanism in which a color band is formed on a retina by eye movement. Explanatory drawing which shows the color image generation model by a color sequential drive system. Explanatory drawing which shows the color image generation model by the combination of a color sequential drive system and a visual system.

Claims (13)

A color light generation unit that repeatedly generates a plurality of color lights at a predetermined frequency in time sequence;
An image generation unit that processes the plurality of color lights so as to sequentially generate images corresponding to each of the plurality of color lights;
The color display device, wherein the predetermined frequency is 180 Hz or more.   The color display device according to claim 1, wherein the predetermined frequency is 250 Hz or more.   The color display device according to claim 1, wherein the predetermined frequency is 300 Hz or more.   The color display device according to claim 1, wherein the color light generation unit includes a light source and a color filter that generates the plurality of color lights from light from the light source. The color light generation unit includes a plurality of light sources that emit different color lights.
The color display device according to claim 1, wherein the plurality of light sources are lit in time sequence.   The color display device according to claim 1, wherein the image generation unit is a reflective electro-optical device.   The color display device according to claim 6, wherein the electro-optical device is a liquid crystal device.   The color display device according to claim 6, wherein the electro-optical device is a digital micromirror device.   The color display device according to claim 1, wherein the image generation unit includes a transmissive electro-optical device.   The color display device according to claim 1, further comprising a lens that projects the image. A color light generation step for repeatedly generating a plurality of color lights at a predetermined frequency in time sequence;
An image generation step of processing the plurality of color lights so as to generate an image corresponding to each of the plurality of color lights in a time sequential manner, and a color display method comprising:
The color display method, wherein the predetermined frequency is 180 Hz or more.   The color display method according to claim 11, wherein the predetermined frequency is 250 Hz or more.   The color display method according to claim 11, wherein the predetermined frequency is 300 Hz or more.

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