WO2014050497A1 - Dispositif d'affichage - Google Patents

Dispositif d'affichage Download PDF

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Publication number
WO2014050497A1
WO2014050497A1 PCT/JP2013/074054 JP2013074054W WO2014050497A1 WO 2014050497 A1 WO2014050497 A1 WO 2014050497A1 JP 2013074054 W JP2013074054 W JP 2013074054W WO 2014050497 A1 WO2014050497 A1 WO 2014050497A1
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WO
WIPO (PCT)
Prior art keywords
luminance
display
period
light
value
Prior art date
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PCT/JP2013/074054
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English (en)
Japanese (ja)
Inventor
誠 秦
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日本精機株式会社
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Publication date
Application filed by 日本精機株式会社 filed Critical 日本精機株式会社
Publication of WO2014050497A1 publication Critical patent/WO2014050497A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/28—Reflectors in projection beam
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B33/00—Colour photography, other than mere exposure or projection of a colour film
    • G03B33/08—Sequential recording or projection
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3433—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices
    • G09G3/346—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices based on modulation of the reflection angle, e.g. micromirrors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/0118—Head-up displays characterised by optical features comprising devices for improving the contrast of the display / brillance control visibility
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0235—Field-sequential colour display
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2380/00—Specific applications
    • G09G2380/10—Automotive applications

Definitions

  • the present invention relates to a display device, and more particularly to a display device that displays an image by a field sequential method.
  • Patent Document 1 discloses a display device that uses a reflective display element DMD (Digital Micro-mirror Device) as a display device that displays an image by a field sequential driving method. This type of display device realizes high-resolution display by reflecting light emitted from a light source by individual mirrors of the DMD based on an external video signal.
  • DMD Digital Micro-mirror Device
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a display device capable of controlling the brightness by a simple method while extending the life of the display element.
  • a display device provides: A display device that displays a predetermined image in a field sequential manner, Light emitting means for emitting light of at least two or more colors; Drive control means for driving and controlling the light emitting means in a field sequential manner so as to emit light of different colors for each subframe period obtained by dividing the frame period which is the display period of the image; A display element having a plurality of reflecting portions for reflecting the emitted light emitted by the light emitting means; Display control means for displaying the image on the display element by changing the reflection state of the emitted light by driving and controlling the plurality of reflection units; Driving current adjusting means for supplying the light emitting means with a driving current adjusted according to the required luminance for each subframe period;
  • the frame period is A display period in which the display element is displaying the image by the display control unit driving the plurality of reflection units and the drive control unit driving the light emitting unit; A non-display period in which the display element is not displaying the image by
  • a display device that displays a predetermined image in a field sequential manner, Light emitting means for emitting light of at least two or more colors; Drive control means for driving and controlling the light emitting means in a field sequential manner so as to emit light of different colors for each subframe period obtained by dividing the frame period which is the display period of the image; A display element having a plurality of reflecting portions for reflecting the emitted light emitted by the light emitting means; Display control means for displaying the image on the display element by changing the reflection state of the emitted light by driving and controlling the plurality of reflection units; Driving current adjusting means for supplying the light emitting means with a driving current adjusted according to the required luminance for each subframe period;
  • the frame period is A display period in which the display element is displaying the image by the display control unit driving the plurality of reflection units and the drive control unit driving the light emitting unit; A non-display period in which the display element is not displaying the image by
  • the ratio of the display period in the frame period is the first ratio when the required luminance is between the first luminance and the second luminance, and the required luminance is the second luminance and the second luminance. Between the third luminance, the second ratio is smaller than the first ratio, It is characterized by that.
  • the present invention it is possible to provide a display device that can control the luminance by a simple method while extending the lifetime of the display element.
  • FIG. 1 It is a figure for demonstrating the mounting aspect of the HUD apparatus which concerns on 1st Embodiment of this invention. It is a schematic block diagram of the HUD apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the structure of an illuminating device. It is a figure for demonstrating the electrical constitution of the HUD apparatus which concerns on 1st Embodiment. It is a figure for demonstrating mainly the display period and non-display period in a display element.
  • (A)-(f) is a timing chart for demonstrating the operation timing of each mirror and each light source which a display element has.
  • (A)-(c) is a figure for demonstrating the drive method of the illuminating device which concerns on 1st Embodiment.
  • (A)-(c) is a figure for demonstrating the drive method of the liquid crystal display element as a comparative example.
  • (A) is a figure of the graph which shows the relationship between the request
  • (B) is a graph showing the relationship between the required luminance and the display period ratio according to the second embodiment of the present invention.
  • (C) is a graph showing the relationship between the required luminance and the display period ratio according to another comparative example.
  • (A) And (b) is a figure for demonstrating the drive method of the illuminating device which concerns on 2nd Embodiment.
  • the display device is a head-up display (HUD) device 1 shown in FIG.
  • the HUD device 1 is arranged on the dashboard of the vehicle 2 and emits display light L representing the generated display image M (see FIG. 2) toward the windshield 3.
  • the display light L reflected by the windshield 3 is viewed as a virtual image V of an image formed in front of the windshield 3 by the observer 4 (mainly the driver of the vehicle 2).
  • the HUD device 1 causes the observer 4 to visually recognize the display image M as the virtual image V.
  • the HUD device 1 includes an illumination device 10, a light intensity detection unit 20, an illumination optical system 30, a display element 40, a projection optical system 60, a screen 70, a plane mirror 81, A concave mirror 82, a housing 90, and a translucent part 91 are provided.
  • the illumination device 10 emits light RGB (illumination light C), which will be described later, toward the illumination optical system 30, and as shown in FIG. 3, the illumination unit 11, the circuit board 12, the multiplexing unit 13, and the like.
  • the illumination means 11 is comprised from the light sources 11r, 11g, and 11b which consist of LED (Light Emitting Diode), for example.
  • the light source 11r emits red light R
  • the light source 11g emits green light G
  • the light source 11b emits blue light B.
  • a drive current is supplied to each of the light sources 11r, 11g, and 11b via the illumination control unit 101 under the control of the control unit 100 described later, and each of the light sources 11r, 11g, and 11b emits light at a predetermined light intensity and timing.
  • the circuit board 12 is a printed circuit board. Light sources 11r, 11g, and 11b are mounted on the circuit board 12.
  • the multiplexing means 13 is emitted from the light sources 11r, 11g, and 11b, combines the arrived lights R, G, and B, and emits them as light RGB.
  • the multiplexing means 13 includes a reflecting portion 13a made of a reflecting mirror, and combining portions 13b and 13c made of dichroic mirrors that reflect light of a specific wavelength but transmit light of other wavelengths. It is configured.
  • the reflection unit 13a reflects the incident green light G toward the multiplexing unit 13b.
  • the multiplexing unit 13b transmits the green light G from the reflecting unit 13a as it is, and reflects the incident red light R toward the multiplexing unit 13c.
  • the light RG obtained by combining the green light G and the red light R is emitted from the combining unit 13b toward the combining unit 13c.
  • the multiplexing unit 13 c transmits the light RG from the multiplexing unit 13 b as it is and reflects the incident blue light B toward the illumination optical system 30.
  • the light RGB hereinafter also referred to as illumination light C
  • illumination light C obtained by combining the light RG and the blue light B is emitted from the multiplexing unit 13 c toward the illumination optical system 30.
  • the luminance unevenness reducing optical means 14 includes a mirror box, an array lens, and the like, and reduces unevenness of light by irregularly reflecting, scattering, and refracting the illumination light C from the multiplexing means 13.
  • the illuminating device 10 converts the light emitted from the illuminating unit 11 into the light RGB (through the above-described combining unit 13 and the luminance unevenness reducing optical unit 14 (and the transmission film 15 described below)). It is emitted toward the illumination optical system 30 as illumination light C).
  • the transmissive film 15 is made of a transmissive member having a reflectivity of, for example, about 5%, and transmits most of the illumination light C that has arrived through the luminance unevenness reducing optical means 14 as it is, but a part of the light has a light intensity. The light is reflected in the direction of the detection unit 20.
  • the light intensity detector 20 is made of a photodiode or the like, receives the illumination light C reflected by the transmission film 15, and detects the light intensity of each of the light R, G, and B. Specifically, the light intensity detection unit 20 outputs a detection signal (voltage) corresponding to the light intensity, and this detection signal is converted into a digital value by an A / D converter (not shown) to obtain light intensity data. The data is output to the control unit 100 described later.
  • the light intensity detection unit 20 only needs to be able to detect the light intensities of R, G, and B. For example, each of the light R, G, and B before being combined is not the optical path of the illumination light C. It may be provided at a location where the light intensity can be detected.
  • the illumination optical system 30 is composed of a concave lens or the like, and adjusts the illumination light C emitted from the illumination device 10 to a size corresponding to the display element 40.
  • the display element 40 is made up of a DMD (Digital Micro-mirror Device) having a plurality of movable micromirrors, and is emitted from the illumination optical system 30 by controlling each mirror in an on / off state.
  • the illuminated illumination light C is appropriately reflected.
  • the display element 40 projects the display image M (light for generating the display image M) toward the projection optical system 60 by reflecting the illumination light C in this way.
  • an electrode is provided below the micromirror, and each mirror is turned on or off by driving each mirror with a very short period (for example, on the order of ⁇ sec). .
  • Each mirror is movable with a hinge as a fulcrum, and when the mirror is in an on state, the mirror surface is tilted by +12 degrees with the hinge as a fulcrum, and when the mirror is in an off state, the mirror surface is tilted by -12 degrees with the hinge as a fulcrum.
  • the on-state mirror reflects the illumination light C from the illumination optical system 30 in the direction of the projection optical system 60, and the off-state mirror does not reflect the illumination light C in the direction of the projection optical system 60.
  • the display element 40 projects the display image M toward the projection optical system 60 by driving each mirror individually.
  • the projection optical system 60 is composed of a concave lens or a convex lens, and is an optical system for efficiently projecting the display light L from the display element 40 onto the screen 70.
  • the screen 70 includes a holographic diffuser, a microlens array, a diffusion plate, and the like.
  • the screen 70 receives the display light L from the projection optical system 60 on the back surface (the lower surface in FIG. 2) and receives the front surface (the upper surface in FIG. 2). Display image M is displayed on the screen.
  • the flat mirror 81 reflects the display light L representing the display image M displayed on the screen 70 toward the concave mirror 82.
  • the concave mirror 82 emits the reflected light in the direction of the windshield 3 by reflecting the display light L that has arrived from the flat mirror 81 on the concave surface. As a result, the virtual image V to be formed becomes larger than the display image M displayed on the screen 70.
  • the display light L reflected by the concave mirror 82 reaches the windshield 3 via the translucent part 91.
  • the housing 90 houses the illumination device 10, the light intensity detection unit 20, the illumination optical system 30, the display element 40, the projection optical system 60, the screen 70, the flat mirror 81, the concave mirror 82, and the like at predetermined positions. , Formed of a light-shielding member.
  • the translucent part 91 is made of a translucent resin such as acrylic and transmits the display light L from the concave mirror 82, and is fitted to the housing 90, for example.
  • the translucent part 91 is formed in, for example, a curved shape so that the external light that has reached does not reflect in the direction of the observer 4.
  • the HUD device 1 includes a control unit 100, an illumination control unit 101, and a display control unit 102, as shown in FIG.
  • the control unit 100 is electrically connected to each of the illumination control unit 101, the display control unit 102, the light intensity detection unit 20, and the ECU (Electronic Control Unit) 5 of the vehicle 2 by various wirings and the like.
  • the illumination control unit 101 is electrically connected to the illumination unit 11 via the circuit board 12, and the display control unit 102 is electrically connected to the display element 40.
  • These control units are mounted, for example, on a printed circuit board (not shown) disposed in the housing 90. These control units may be disposed outside the HUD device 1 and electrically connected to each unit by wiring.
  • the control unit 100 controls the display operation of the HUD device 1 and includes an FPGA (Field Programmable Gate Array), a microcontroller, an ASIC (Application Specific Integrated Circuit), and the like, and includes a CPU, a memory (RAM, ROM), and the like. Prepare.
  • the control unit 100 (CPU) controls each unit as described below by reading and executing a program necessary for the operation of the HUD device 1 stored in advance in the ROM. Specifically, a video signal S for displaying the display image M is input from the ECU 5 to the control unit 100 by LVDS (Low Voltage Differential Signal) communication or the like.
  • LVDS Low Voltage Differential Signal
  • the control unit 100 controls (i) illumination control data D1 for controlling the illumination device 10 at the luminance and light emission timing required by the video signal S. (Ii) display control data D2 for displaying the display image M requested by the video signal S on the display element 40 is supplied to the display control unit 102.
  • the control unit 100 acquires light intensity data from the light intensity detection unit 20 and corrects a deviation between the light luminance required by the video signal S and the actual light emission luminance of the lighting device 10 by an appropriate method.
  • control unit 100 adjusts the luminance when the switching signal from the vehicle 2 side, the operation signal based on the operation of the observer 4, the illuminance sensor (not shown) that detects the illuminance of external light (for example, the light transmission unit 91) It may be based on a detection signal or the like from (provided on the back surface). In this way, the control unit 100 controls the output operation of the display image M.
  • a frame F (for example, 1/60 sec), which is a cycle for displaying the display image M, is composed of subframes SF (see FIG. 6) divided into a plurality of times.
  • the illumination control unit 101 includes a driver IC (Integrated Circuit), a switching circuit using transistors, and the like, and the light intensity and timing required by the illumination control data D1 for the light sources 11r, 11g, and 11b of different colors for each subframe SF.
  • the lighting device 10 is controlled by a field sequential drive system that sequentially switches at a high speed.
  • the display control unit 102 includes a driver IC, a switching circuit, and the like.
  • the display control unit 102 changes each mirror of the display element 40 using a PWM (Pulse Width Modulation) method (that is, changes the ON time ratio). Etc.), the light R, G, B emitted from the illumination device 10 is reflected in the direction of the screen 70, so that each light emission color of the light sources 11r, 11g, 11b is added as a basic color.
  • the display image M is expressed in full color using color mixing by the mixing method.
  • the control unit 100 generates illumination control data D1 and display control data D2 based on the video signal S from the outside.
  • the illuminating device 10 emits the illumination light C to the display element 40 by the field sequential driving method based on the illumination control data D1.
  • the display element 40 projects the illumination light C from the illumination device 10 on the screen 70 as a display image M by performing on / off control of each mirror of the display element 40 based on the display control data D2.
  • the display light L representing the display image M displayed on the screen 70 is reflected by the plane mirror 81 toward the concave mirror 82.
  • the display image M is enlarged to a predetermined size by the concave mirror 82, and the display light L representing the enlarged display image M is reflected by the windshield 3, so that the display image M is displayed in front of the windshield 3.
  • a virtual image V of M is formed.
  • the HUD device 1 causes the observer 4 to visually recognize the display image M as the virtual image V.
  • the frame F (cycle for displaying the display image M) includes a display period Fa in which each mirror E of the display element 40 is normally driven and a non-display period Fb in which the non-display period is driven.
  • the display period Fa is a period during which each mirror E of the display element 40 is normally driven. Specifically, during the display period Fa, the illumination device 10 emits the illumination light C in the direction of the display element 40 by the field sequential driving method based on the illumination control data D1, and the display element 40 changes to the display control data D2. This is a period during which the illumination light C from the illumination device 10 is projected as a display image M toward the screen 70 by performing on / off control of individual mirrors of the display element 40 based on this.
  • the non-display period Fb is a period during which the illumination device 10 is turned off (all the light sources 11r, 11g, and 11b are turned off) (see FIGS. 6D to 6F), and each mirror E of the display element 40 is displayed. Is a period for which on / off control is performed at a predetermined cycle.
  • driving in which each mirror E is on / off controlled in a predetermined cycle is referred to as “non-display period driving”.
  • the ratio of the display period Fa in the frame F is “display period ratio A”.
  • display period Fa a period during which the mirror E is turned on (turned on) is referred to as “on drive period Fap within display period”, and a period during which the mirror E is driven off (turned off) is referred to as “off drive period Faq within display period”.
  • non-display period Fb a period during which the mirror E is on-driven is referred to as an “non-display period on-drive period Fbp”, and an off-drive period is referred to as an “non-display period off-drive period Fbq”.
  • total on-drive period Fp the total period during which the mirror E is on-driven
  • total off-drive period Fq the total period during which the mirror E is driven off
  • each of the mirrors E is controlled to be on / off so that the on period and the off period of each mirror E in the frame F are substantially equal (including just and equal). Specifically, referring to FIG.
  • control unit 100 adjusts the non-display period on-drive period Fbp and the non-display period off-drive period Fbq so that the sum (total off-drive period Fq) with the inner off-drive period Fbq becomes substantially equal.
  • the control unit 100 adjusts so that the display period ratio A is constant at 50% and the total on-drive period Fp and the total off-drive period Fq are substantially equal.
  • each predetermined frame F among the mirrors E of the display element 40, those that display green in a single color are “monochromatic mirrors Ea”, red and green.
  • the non-display period drive will be described in detail with “mixed color mirror Eb” for displaying the mixed color of “N” and “extinguishing mirror Ec” for not displaying anything (that is, not reflecting the illumination light C in the direction of the projection optical system 60).
  • the monochromatic mirror Ea is on-controlled at the lighting timing of the light source 11g (see FIG. 6E) in the display period Fa based on the display control data D2, and in the non-display period Fb.
  • the non-display period on-drive period Fbp and the non-display period in the non-display period Fb are controlled so that the total on-drive period Fp, which is the sum of the on-drive periods in the frame F, is approximately half of the frame F.
  • the off drive period Fbq within the period is adjusted, and the non-display period drive is performed by the single-color mirror Ea based on the on drive period Fbp within the non-display period and the off drive period Fbq within the non-display period.
  • the control unit 100 drives each mirror so that the ON driving is continued in the non-display period Fb for the ON driving period Fbp within a predetermined non-display period.
  • the unit 100 performs on-drive and off-drive within the non-display period Fb, an on-drive period Fbp within the non-display period, and an off drive period Fbq within the non-display period.
  • the total ON drive period Fp and the total OFF drive period Fq may be adjusted to be substantially equal.
  • the non-display period driving is controlled to be turned on over the non-display period Fb.
  • the HUD device 1 adjusts the total on-drive period Fp and the total off-drive period Fq to be substantially equal, so that the mirror E of the display element 40 is in one of the on and off states. Can be prevented from sticking, and the life of the display element 40 can be extended.
  • the illumination control unit 101 Under the control of the control unit 100 (based on the illumination control data D1), the illumination control unit 101, as described above, at the timing shown in FIG. 6 (ON timing in FIG. 6), Each of 11g and 11b is caused to emit light appropriately.
  • the illumination control unit 101 controls the light sources 11r, 11g, and 11b with the PWM method as shown in FIGS. 7A and 7B with the light intensity (luminance) required by the illumination control data D1.
  • the control by the PAM (pulse amplitude modulation: Pulse Amplitude Modulation) method is properly used and driven appropriately.
  • FIGS. 8A to 8C Before describing in detail the control peculiar to the present embodiment using the PWM and PAM methods, referring to FIGS. 8A to 8C, as a display element of a comparative example, an LED is used.
  • a PAM / PWM control method of a liquid crystal display element (TFT (Thin Film Transistor) liquid crystal) that performs transmissive display with light will be described.
  • FIGS. 8A and 8B consider a case where the required luminance changes from the maximum luminance Lmax, which is the maximum, to the minimum luminance.
  • Lmax which is the maximum
  • both the current value and the duty ratio are maximized (see Amax shown in FIG. 8A and the duty ratio 100% shown in FIG. 8B).
  • the required brightness decreases from Lmax, the light is first dimmed by PAM control as shown in FIG. This is because the gamma value (color tone) change accompanying the change in the current value of the LED is performed on the high luminance side so as not to affect the appearance (at high luminance, it is difficult to notice the change in color tone).
  • the higher the current of the LED the less the linearity of the relationship between the current and the speed of light, and the lower the efficiency.
  • the current value of the LED is controlled to be constant as shown in FIG. 8A, and then the duty ratio is gradually lowered as shown in FIG. The light intensity is reduced by shortening the ON period, and finally the minimum luminance is realized.
  • the actual display brightness as shown in FIG. Is in line with the required brightness, and smooth dimming control can be realized.
  • a dimming control requires a large capacity memory for LED drive control, there is room for improvement in terms of memory capacity and cost reduction of the display device system.
  • the required luminance is determined at the light emission timing of each of the light sources 11r, 11g, and 11b (see the ON periods in FIGS. 6D to 6F).
  • This is a drive current supply method for realizing this, and is executed based on, for example, table data stored in advance in the ROM (it may be calculated using a predetermined mathematical expression).
  • the display period ratio A is a constant value (50%) regardless of the required luminance.
  • the control unit 100 sets both the PAM control value (current value) and the PWM control value (duty ratio) to the maximum values (Amax shown in FIG. 7A, FIG. 7). (Refer to 100% duty ratio shown in (b)).
  • the required luminance decreases, the light is first dimmed by PAM control (that is, by controlling the current value) (see between Lmax and La in FIG. 7A).
  • the duty ratio is changed stepwise (discontinuously) by PWM control as shown in FIG. 7B, and as shown in FIG.
  • the PAM control is performed to increase the current value (see Ax in the same figure).
  • the display brightness and chromaticity at the discontinuous points of the current value and the duty ratio are adjusted to be constant (adjustment in the Assy process is necessary).
  • the current value is gradually lowered from the predetermined value Ax as shown in FIG. 7A, but the duty ratio is constant as shown in FIG. 7B. Of Ra (%). Thereby, dimming control is realized.
  • the control unit 100 repeats the same control as the procedures [2] and [3].
  • FIG. 9C shows an example in which the display period ratio A is changed stepwise according to the required luminance in a display element made of DMD.
  • the control method as shown in FIG. 9C in principle, smooth dimming / toning control is possible by appropriately controlling the LEDs as the display period ratio A changes.
  • a control method as shown in FIG. 9C is adopted, a huge amount of memory is required to hold DMD drive sequence data, which is not practical.
  • the RGB light emission timing is different for each drive sequence (for each different display period ratio A)
  • the LED control data also becomes enormous. Therefore, the above-described control method according to the present embodiment (FIGS. 7A, 7B, and 9A) realizes smooth dimming toning control and reduces the necessary memory capacity. From this point of view, it can be seen that it is preferable.
  • the HUD device 1 is a display device that displays a predetermined image M by a field sequential method, and is an illumination unit 11 (light emitting unit) that emits light of at least two or more colors. And the illumination means 11 in a field sequential manner so that light of a different color is emitted for each subframe SF (subframe period) obtained by time-dividing the frame F (frame period) which is the display cycle of the image M.
  • illumination unit 11 light emitting unit
  • Drive control means (control section 100 and illumination control section 101) for driving control, display element 40 having a plurality of mirrors E (an example of a reflection section) that reflects illumination light C emitted from illumination means 11, and the plurality of the display elements 40
  • Display control means for controlling the mirror E to change the reflection state of the illumination light C to display the image M on the display element 40 (the control unit 100 and the display control) 101), provided for each sub-frame SF, the required drive current adjusting means for supplying a drive current to the illumination means 11 is adjusted in accordance with the luminance being (control unit 100 and the illumination control unit 101), a In the frame F, the display control unit drives the plurality of mirrors E, and the drive control unit drives the illumination unit 11, so that the display element Fa displays the image M, and the display period Fa
  • the display control means drives the plurality of mirrors E, and the drive control means turns off the illumination means 11, thereby having a non-display period Fb in which the display element 40 is not displaying the image M.
  • the ratio of the display period Fa to the frame F is constant,
  • the drive current adjusting means is configured to obtain a required luminance (including a value indicated by the luminance as appropriate; hereinafter the same) between the first luminance and the second luminance smaller than the first luminance by pulse width modulation control (PWM control).
  • PWM control pulse width modulation control
  • the duty ratio of the driving current is kept constant at the first value, and the duty ratio of the driving current is smaller than the first value between the second luminance and the third luminance smaller than the second luminance.
  • the duty ratio is changed stepwise, and the current value control (PAM control) causes the required brightness between the first brightness and the second brightness to be equal to the drive current.
  • the current value is gradually decreased from the first luminance toward the second luminance, the current value is increased at a change point where the duty ratio changes from the first value to the second value, and the required luminance is the second luminance.
  • the third luminance the current value of the drive current is Gradually decreases as the second luminance toward the third luminance, adjusting the drive current supplied to the light emitting means in a manner that.
  • the memory capacity for driving the display element 40 made of DMD can be reduced.
  • the PWM control value (for example, the duty ratio) needs to be synchronized with the drive of the display element 40, and thus requires various parameters. Since the variation of the values that can be taken by the PWM control value is drastically reduced by the control, the data for controlling the ON period of each of the light sources 11r, 11g, and 11b can be reduced. Capacity can be reduced.
  • FIG. 9A an example in which the display period ratio A is constant regardless of the required luminance is shown. From now on, display is performed according to the required luminance. A second embodiment in which the period ratio A changes will be described. Since the configuration of the HUD device 1 is the same as that of the first embodiment, hereinafter, the same reference numerals are used for the respective configurations, and the control method will be described differently from the first embodiment.
  • the control unit 100 switches the display period ratio A depending on the brightness at which the display image M is displayed (depending on the requested brightness). Specifically, as shown in FIG. 7B, the control unit 100 sets the display period ratio A to 50% when the required luminance is smaller than the predetermined luminance threshold Lt, and the required luminance is the luminance threshold. In the case of Lt or more, the display period ratio A is set to 70%.
  • the non-display period Fb occupying the frame F is increased (that is, display By adjusting the period ratio A from 70% to 50%), the total on-drive period Fp and the total off-drive period Fq in the frame are adjusted to be substantially equal while maintaining the luminance of the display image M. It is possible to prevent each mirror E of the display element 40 from sticking to either the on or off state. As a result, the lifetime of the display element 40 can be extended.
  • the drive control method of the illumination device 10 is the same, but in the second embodiment, the control unit 100 is configured as shown in FIG. ) And (b), the display period ratio A is changed at a point where the duty ratio is discontinuous in PWM control (see the point where the required luminance La is shown in FIG. 10B).
  • the PAM control value current value
  • the display period ratio A is increased from 70% to 50%. It can be seen from the fact that the current value is earned at the point where the brightness will decrease and decrease.
  • the RGB drive sequence the light emission timing of RGB of each of the light sources 11r, 11g, and 11b (how to arrange in time series) and the light emission period (on period) changes. Based on this, it is necessary for the control unit 100 to drive the illumination device 10 (light sources 11r, 11g, and 11b) by the PAM and PWM methods.
  • the HUD device 1 is a display device that displays a predetermined image M by a field sequential method, and is an illumination unit 11 (light emitting unit) that emits light of at least two or more colors. And the illumination means 11 in a field sequential manner so that light of a different color is emitted for each subframe SF (subframe period) obtained by time-dividing the frame F (frame period) which is the display cycle of the image M.
  • illumination unit 11 light emitting unit
  • Drive control means (control section 100 and illumination control section 101) for driving control, display element 40 having a plurality of mirrors E (an example of a reflection section) that reflects illumination light C emitted from illumination means 11, and the plurality of the display elements 40
  • Display control means for controlling the mirror E to change the reflection state of the illumination light C to display the image M on the display element 40 (the control unit 100 and the display control) 101), provided for each sub-frame SF, the required drive current adjusting means for supplying a drive current to the illumination means 11 is adjusted in accordance with the luminance being (control unit 100 and the illumination control unit 101), a In the frame F, the display control unit drives the plurality of mirrors E, and the drive control unit drives the illumination unit 11, so that the display element Fa displays the image M, and the display period Fa
  • the display control means drives the plurality of mirrors E, and the drive control means turns off the illumination means 11, thereby having a non-display period Fb in which the display element 40 is not displaying the image M.
  • the drive current adjusting means keeps the duty ratio of the drive current constant at the first value between the first brightness and the second brightness smaller than the first brightness by the pulse width modulation control, Between the second luminance and the third luminance smaller than the second luminance, the duty ratio is changed stepwise by keeping the duty ratio of the drive current constant at the second value smaller than the first value.
  • the current value control when the required luminance is between the first luminance and the second luminance, the current value of the driving current is gradually decreased from the first luminance to the second luminance, and the duty ratio is the first luminance.
  • the current value is increased at the changing point where the value changes from 1 to the second value, and when the required luminance is between the second luminance and the third luminance, the current value of the driving current is changed from the second luminance to the third luminance.
  • the light is gradually reduced as it goes to Morphism adjust the drive current supplied to the unit,
  • the ratio of the display period Fa to the frame F is the first ratio when the required luminance is between the first luminance and the second luminance, and the required luminance is between the second luminance and the third luminance. Then, the second ratio is smaller than the first ratio.
  • the change point of the display period ratio A is synchronized with the change point of the PWM control value, so that the control is simple as described above, and the driving is long-lived. Since the display period ratio A can be 50%, the life of the display element 40 can be extended.
  • the luminance threshold Lt is the required luminance La shown in FIGS. 10A and 10B
  • the luminance threshold Lt may be a point where the duty ratio in PWM control becomes discontinuous, and may be Lb shown in the figure or other points.
  • the present invention is not limited thereto. You may make it radiate
  • an example of a vehicle on which the HUD device 1 is mounted is a vehicle, but is not limited thereto.
  • the HUD device 1 can also be installed on other vehicles (ships, airplanes, etc.). Furthermore, it is not restricted to what is installed in a vehicle.
  • the HUD device 1 is configured integrally with the dashboard of the vehicle.
  • the HUD device 1 is, for example, a stationary type (retrofitted type) installed on the dashboard of the vehicle. May be.
  • the HUD device 1 has been described as an example of a display device using the field sequential driving method, but the present invention is not limited to this. Other display devices may be used. However, since the HUD device allows the display image to be visually recognized overlaid on the background (landscape), in particular, considering that the display luminance needs to be adjusted, as a display device that performs PAM and PWM control as described above, HUD devices are preferred.
  • the present invention can be applied to a display device that is mounted on a vehicle and displays various vehicle information as images, for example, as a display device that is mounted on a mobile body including a car, a motorcycle, an agricultural machine, or a construction machine.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal (AREA)
  • Projection Apparatus (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)

Abstract

La présente invention permet d'effectuer une commande de luminosité par le biais d'un procédé simple tout en augmentant la durée de vie d'un élément d'affichage. Ce dispositif d'affichage affiche une image prédéterminée par le procédé séquentiel de champ. Une trame comprend une période d'affichage et une période de non-affichage pendant qu'un DMD est commandé, mais qu'aucune image n'est affichée. Le rapport de la période d'affichage dans la trame est uniforme. Le dispositif d'affichage ajuste le courant de commande fourni à une source de lumière par le procédé suivant : par une commande MID, le facteur de marche d'une luminosité requise est modifié pas à pas entre une première luminosité et une deuxième luminosité, ainsi qu'entre la deuxième luminosité et une troisième luminosité ; et par une commande MIA, la valeur du courant de commande est modifiée entre la première luminosité et la deuxième luminosité de manière telle que la valeur du courant diminue progressivement de la première luminosité à la deuxième luminosité, la valeur du courant est augmentée en un point de changement du facteur de marche, et la valeur du courant de commande est modifiée entre la deuxième luminosité et la troisième luminosité d'une manière telle que la valeur du courant diminue progressivement de la deuxième luminosité à la troisième luminosité.
PCT/JP2013/074054 2012-09-26 2013-09-06 Dispositif d'affichage WO2014050497A1 (fr)

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EP3509056A4 (fr) * 2016-08-31 2020-05-20 Nippon Seiki Co., Ltd. Dispositif d'affichage de type à projection
CN111445843A (zh) * 2019-01-17 2020-07-24 米彩股份有限公司 显示器驱动模块及驱动方法
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JP6390893B2 (ja) * 2014-06-16 2018-09-19 日本精機株式会社 Ｄｍｄ表示装置、ヘッドアップディスプレイ装置
JP6554174B2 (ja) * 2015-10-06 2019-07-31 マクセル株式会社 ヘッドアップディスプレイ
WO2018061744A1 (fr) * 2016-09-27 2018-04-05 日本精機株式会社 Dispositif d'affichage
WO2018097121A1 (fr) * 2016-11-24 2018-05-31 日本精機株式会社 Appareil d'affichage d'images et afficheur tête haute
WO2018123554A1 (fr) * 2016-12-26 2018-07-05 日本精機株式会社 Dispositif d'affichage
US10712559B2 (en) 2017-01-17 2020-07-14 Nippon Seiki Co., Ltd. Display device
WO2023219310A1 (fr) * 2022-05-11 2023-11-16 삼성전자 주식회사 Dispositif électronique, et procédé de commande associé

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CN107068021A (zh) * 2016-02-05 2017-08-18 大陆汽车电子(芜湖)有限公司 基于帧同步的平视显示器的adc采样方法
EP3509056A4 (fr) * 2016-08-31 2020-05-20 Nippon Seiki Co., Ltd. Dispositif d'affichage de type à projection
CN108181094A (zh) * 2017-12-25 2018-06-19 中国航空工业集团公司洛阳电光设备研究所 一种平视显示器字符亮度及线宽测量方法
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WO2023112485A1 (fr) * 2021-12-15 2023-06-22 パナソニックＩｐマネジメント株式会社 Dispositif d'affichage d'image et circuit de commande de source de lumière

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