JP2004062109A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device which varies priority of an image quality element depending on use environment while reducing deterioration speed of photoelectric conversion efficiency and which makes an image desirably recognized in visual characteristic. <P>SOLUTION: In this projection type display device, light radiating from an electroluminescent element having a plurality of pixels adaptable to individual modulation and from the individual modulated pixels inside this electroluminescent element are projected to an object by a projection lens to display an image. The device is characterized in that it detects the brightness of the environment illuminating the object and that it controls the luminance of the electroluminescent element linked with this brightness of the environment. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image display device. In particular, the present invention relates to a display device that enlarges and projects an element that emits an image pattern onto a projection target, that is, a projector display device.
[0002]
[Prior art]
In a conventional projector type display, a liquid crystal panel or a micromirror device is normally used as a light modulation element for switching, and transmission and blocking or deflection of light are controlled to project selected light onto a screen. The video was displayed above.
[0003]
However, since the liquid crystal panel or the micromirror device is used as the light modulation element in the display as described above, light in a state that does not necessarily contribute to projection is absorbed as unnecessary energy by the polarization element or the light absorbing medium, and is eliminated. It is assumed that In addition, in the case of liquid crystal, unnecessary illumination light must exist due to light transmittance, aperture efficiency of each pixel, and polarization control accuracy. In a micromirror device, aperture efficiency of each pixel and projection by oblique incidence illumination This is based on the fundamental premise that it is difficult to effectively use an axially symmetric optical system with respect to the numerical aperture of the lens and the NA of the illumination system. Therefore, in order to brighten a displayed image, a metal halide or a high-pressure mercury lamp is used as a light source. However, a point that a high voltage must be used as a light source voltage and a problem that a light source generates high heat arises separately. ing.
[0004]
As means for fundamentally solving such low energy use efficiency, JP-A-11-67448 (Toyota Central Research Institute, Inc.), WO99 / 49358 (Mitsubishi Electric Co., Ltd.), No. 66301 (Seiko Epson Corporation). In the above three cases, as a light-emitting panel (organic EL panel) in which organic electroluminescent elements (organic EL elements) are arranged in a matrix, each organic EL element of the light-emitting panel is driven to emit light based on image information, and is projected by a projection optical system. Projection display on a display object has been proposed. Since the organic EL element is a self-luminous element, another light source is not required. Since the organic EL panel emits light in accordance with video information, a transmission type liquid crystal panel or the like is unnecessary, and thus, it is obtained. The light can be used effectively for display. This makes it possible to easily obtain a high-brightness display at low power without generating unnecessary light energy, and to output an image only with the organic EL panel. The effect that it is easy to reduce the size and weight of the device can be expected.
[0005]
On the other hand, since a liquid crystal panel or a micromirror device is used as the light modulation element, the maximum output luminance distribution of each pixel modulated by the modulation panel is the same as the illuminance distribution of the illumination system that illuminates the light modulation element by transmission or reflection. It depends. Therefore, the illuminance distribution is designed according to the configuration of the illumination optical system.However, when a gas discharge lamp using a parabolic or spheroidal mirror is used, the light beam has an atypical Gaussian distribution, and this distribution is In general, conversion into a uniform illuminance distribution is performed by an integrated optical system, and it is difficult to provide a purposeful non-uniform illuminance distribution.
[0006]
To solve this problem, Japanese Patent Application Laid-Open No. 2000-075406 (Futaba Electronics Co., Ltd.) proposes to reduce the amount of transmitted light off the optical axis of the projection lens so that the illuminance of the screen as a projection object is intentionally uniform. In order to compensate for this, a proposal has been made to provide a panel-shaped surface-emitting light source for illuminating the light modulation panel with a luminance distribution. In the embodiment as the panel-shaped surface emitting light source, a field emission type fluorescent light source and a charge injection type organic EL element are used. In this publication, a light source for illuminating a light modulation element using a liquid crystal panel or a micromirror device is described, but the same effect is obtained even when the light source itself is a light modulation element.
[0007]
[Problems to be solved by the invention]
However, the organic electroluminescent device has a problem in durability such that the efficiency of the photoelectric conversion efficiency is gradually reduced, and the organic electroluminescent material itself undergoes a chemical structural change and the potential energy thereof is increased. In addition, the organic electroluminescent layer is mixed with a fluorescent or phosphorescent material and a material for dispersing the material or a material for improving the electric conduction characteristics in order to repeatedly emit light energy according to the displacement of the organic electroluminescent layer. , The probability that an organic electroluminescent material that emits light by causing a chemical structural change changes to a form other than the desired change form is 0% because the state distribution function is discrete at a temperature of absolute zero or more. Is not in principle. For this reason, the rate of change other than the desired change form affects the state stability of the material, the combination with the binder environmental medium material, the applied electric field strength, the hydrolysis due to the humidity environment, etc. It is considered that the main factor is acceleration of deterioration due to a self-heating temperature parameter due to generation of heat energy in the photoelectric conversion process. The rate of this degradation is an accelerated reaction substantially in accordance with the Arrhenius reaction rate relational expression. Therefore, if light emission is driven in a low temperature state with a low power input, the rate of change in photoelectric conversion efficiency is slow and the life is long.However, in order to increase the emission luminance, the more the supply power is increased, the more the photoelectric conversion efficiency increases. The change in conversion efficiency is exponentially short-lived, and if the quality guarantee period of ordinary consumer products is one year, stable light emission for thousands to tens of thousands of hours is required, resulting in bright and high-quality images. The more the display is to be realized, the more such a fundamental problem that the quality stability deteriorates.
[0008]
Further, in the usage state of the projection display device, an object such as a screen for projecting an image is an object placed under an illumination environment in a room or a place, and observation of the image recognizes diffused light from the object. Therefore, in order to sharpen the black-and-white contrast of the projected image, it is common to use a dark illumination environment for illuminating an object such as a screen. The projection of a movie is a typical example. On the other hand, a presentation screen display or the like requires local lighting for reference of a viewer's material and memo work, and thus may be used under a certain lighting environment. Therefore, the usage environment of the projection display device changes depending on the purpose. Also, in a bright usage environment, the importance of displaying a brighter projected image increases, and in a dark usage environment, image quality such as uniformity, contrast clarity, and even color reproducibility of the projected image becomes important. is there.
[0009]
[Means for Solving the Problems]
The present invention is to control the brightness and illuminance uniformity in the image quality according to the usage environment of the projection display device, and the electroluminescent element having a plurality of individually modulatable pixels, In a projection display device, an image is displayed by projecting light emitted from individual modulated pixels in an electroluminescent element onto an object by a projection lens, and illuminates an object such as a screen for projecting the image. The brightness of the environment is detected, and in conjunction with the brightness of the environment, when the lighting environment is dark, the overall maximum emission brightness of the electroluminescent element is reduced, and the illuminance distribution on the projection object such as a screen is uniform. By correcting the distribution of the maximum emission luminance of each pixel arranged in the electroluminescent element so as to obtain a bright projected image display in a bright use environment, and perform a bright projected image display in a dark use environment. By making the illuminance of the projected image uniform and by reducing the power injected into the organic electroluminescent element, the temperature rise of the electroluminescent element is reduced, and the chemical change rate of the organic phosphor material is reduced. It is intended to delay the deterioration of the photoelectric conversion efficiency and prolong the quality maintenance period of the projection display device.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a projection display device according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of a main optical system constituting the projection display device.
Reference numeral 1 denotes an electroluminescent element that emits light as image information as light emission pattern information. The electroluminescent element 1 emits light based on an electric signal from a controller 9 that electrically controls the electroluminescent element according to a signal. . Light emitted from the electroluminescent element 1 is captured by a projection lens 2 and projected on a screen 3, which has light diffusion characteristics on its surface. It is configured to recognize an image. Further, as the projection display device, the screen 3 may be a reflection type or a transmission type. On the other hand, since the energy corresponding to the energy conversion loss of the photoelectric conversion efficiency of the electroluminescent device 1 is mostly converted to thermal energy, a temperature gradient is generated on the back surface of the electroluminescent device 1 by the Seebeck effect, and The low-temperature gradient surface of the Peltier element 4 capable of performing a cooling action is brought into close contact with the back surface of the electroluminescent element 1 to cool the element. At this time, a thermocouple (not shown) is brought into contact with the electroluminescent element 1 to perform temperature control by using a means for monitoring the temperature. On the other hand, on the high-temperature gradient surface of the Peltier device 4 corresponding to the surface opposite to the electroluminescent device 1, the blowing fan 5 cools the air at room temperature. The configuration of the electroluminescent device 1 used here will be described later.
[0011]
On the other hand, before the projection type display device projects and displays an image on the screen 3, the environment illuminance illuminating the screen 3 is condensed on the photoelectric conversion sensor 8 by the condenser lens 7 arranged near the projection lens, and the photoelectric conversion sensor 8 performs photoelectric conversion. The output of the sensor 8 is sent to the controller 9 and stored as environmental illuminance data. Based on the environmental illuminance data, the controller 9 determines whether the entire maximum light emission luminance of the electroluminescent element 1 and each pixel disposed in the electroluminescent element 1 The maximum light emission luminance distribution is controlled. Further, the detection of the environmental illuminance illuminating the screen 3 is performed by partially detecting the outside in the image projection area, and in parallel with the time when the projection display device projects and displays the image on the screen 3, the electroluminescent element is detected. The maximum light emission luminance of the entire pixel 1 or each pixel may be controlled in real time. The control method will be described later.
[0012]
Next, a second embodiment of the projection display apparatus of the present invention will be described with reference to FIG. FIG. 2 is a sectional view of a main optical system constituting the projection display device.
[0013]
Reference numerals 1R, 1G, and 1B denote electroluminescent elements that emit light of colors that control the three primary colors of red, green, and blue, respectively, and each include a plurality of pixels that emit image information as light emission pattern information. Each of the electroluminescent elements 1R, 1G, and 1B emits light of a color in charge based on an electric signal from a controller 9 that electrically controls the electroluminescent element according to an image signal. The light emitted from the electroluminescent elements 1R, 1G, and 1B is color-combined by a multiplexing prism 6. The multiplexing prism 6 reflects a red light and transmits a cyan light and a dichroic filter 6R reflects a blue light and transmits a yellow light. This is generally called a cross dichroic prism in which the dichroic filters 6B are arranged in a cross shape, and thus has a characteristic of transmitting green without being affected. By using the multiplexing prism 6, light emitted from the electroluminescent element 1R responsible for emitting red image information is deflected in the direction of the projection lens 2 by the dichroic filter 6R, and responsible for emitting blue image information. The light emitted from the electroluminescent element 1B is deflected by the dichroic filter 6B in the direction of the projection lens 2, and the light emitted from the electroluminescent element 1G responsible for emitting green image information is projected without being deflected. The light travels in the direction of the lens 2. However, it is needless to mention that a plurality of arranged pixels in each of the electroluminescent elements 1R, 1G, and 1B are adjusted or mechanically or electrically compensated so that the respective predetermined pixels relatively overlap with a predetermined accuracy. Absent. In addition, the multiplexing prism 6 may use a multiplexing means using a 3P prism, which is often used in a video receiving color separation optical system, in addition to the cross dichroic prism shown in the figure. Next, the multiplexed light modulated as a color is captured by the projection lens 2 and projected on a screen 3, which has a light diffusion characteristic on its surface. The image is recognized by looking at the image. Further, as the projection display device, the screen 3 may be a reflection type or a transmission type. On the other hand, as described in the first embodiment of FIG. 1, each of the electroluminescent elements 1R, 1G and 1B is cooled by a cooling means using a Peltier element 4 and a blower fan 5 on the back surface. In the cooling control, a thermocouple (not shown) is brought into contact with the electroluminescent element to perform temperature control by using a means for monitoring the temperature in combination. The configuration of the electroluminescent elements 1R, 1G, and 1B used here will be described later.
[0014]
On the other hand, similarly to the first embodiment, the condensing lens 7 arranged near the projection lens photoelectrically converts the ambient illuminance illuminating the screen 3 before the projection display device projects and displays the image on the screen 3. The light is condensed on the sensor 8 and the output of the photoelectric conversion sensor 8 is sent to the controller 9 and stored as environmental illuminance data. Based on the environmental illuminance data, the controller 9 causes the electroluminescent elements 1R, 1G, and 1B to emit the maximum light. It controls the luminance and the maximum light emission luminance distribution of each pixel arranged in the electroluminescent element. Further, the detection of the environmental illuminance illuminating the screen 3 is performed by partially detecting the outside in the image projection area, and in parallel with the time when the projection display device projects and displays the image on the screen 3, the electroluminescent element is detected. The maximum light emission luminance of the entire 1R, 1G, 1B or each pixel may be controlled in real time.
[0015]
Next, the structure of the electroluminescent device 1 used in the first embodiment will be described with reference to FIG. As shown in FIG. 3 (b), the basic structure of the electroluminescent element used is as follows: a transparent glass substrate 10 is used as a base material, and thin film electroluminescent material layers 11, 12, 13 are made of an ITO (indium tin oxide) transparent thin film electrode 14. In order to efficiently inject only hole carriers into the electroluminescent material, the hole transport layer 16 is made of the ITO transparent thin film electrode 14 and the thin film electroluminescent material layers 11, 12, and 13. It is arranged between. When used as a projection-type modulation light source, a dielectric lens provided outside the ITO transparent thin-film electrode 14 is used for the purpose of increasing the ratio of capturing the emitted light by the projection lens and increasing the photoelectric conversion efficiency. An optical resonance structure is constituted by the body multi-layer reflective half mirror layer 17 and the light reflecting surface of the metal thin film electrode 15, and the light emission direction of the glass substrate 10 is adjusted by resonance without reaching the state where the stimulated radiation action occurs. Directivity is provided in the vertical direction. Also, there is an effect of realizing the effect of narrowing the band of the emission wavelength spectrum at the same time, and it becomes possible to design the emission light wavelength by designing the resonance distance. The light emitting surface is on the transparent glass substrate 10 side. The above is the basic structure of the electroluminescent device 1. Each luminescent pixel is composed of an ITO transparent thin film electrode 14 and a wiring matrix arrangement of a metal thin film electrode 15, and the emission wavelength on the order of 1 nanometer is adjusted by the spacing of the resonance mirror. However, the emission colors such as red, green, and blue are determined by the electroluminescent material. As shown in FIG. 3A, the electroluminescent material for each color is 11, the electroluminescent material for red, and the electric field for green. By arranging the light emitting material as 12 and the electroluminescent material in charge of blue as 13, the electroluminescent device 1 expressing full color is realized. On the other hand, the patterning of the electroluminescent materials 11, 12, and 13 is generally performed by coating the substrate with a fluorescent material by a vapor deposition method. That is, in order to form the electroluminescent device 1 having three primary color light emitting pixels, Although the manufacturing process is multi-step, the unnecessary portions for each color are masked by resist patterning, and the pattern can be arranged by sequentially coating the electroluminescent materials of the three primary colors by a lift-off method. .
[0016]
The structure of the electroluminescent elements 1R, 1G and 1B used in the second embodiment is the same as that described in the first embodiment as shown in FIG. The electroluminescent element 1R has an electroluminescent material for red in which 11 is disposed, the electroluminescent element 1G has an electroluminescent material for green in which 12 is disposed, and an electroluminescent element. The element 1B has 13 electroluminescent materials for blue.
[0017]
Next, a method of controlling the light emitting state of the electroluminescent element 1 according to the lighting environment, which is the gist of the present invention, will be described with reference to FIG. After turning on the power of the projection display apparatus and starting (step 1), each brightness is determined based on the environmental illuminance value of the screen 3 (step 2) detected by the condenser lens 7 and the photoelectric conversion sensor 8 described above. Accordingly, N states are set, and it is determined which number of the brightness state is in. When there is a predetermined m-th (N ≧ m ≧ 1) environmental illuminance, the m-th intensity attenuation distribution table m is set in the maximum luminance conversion table corresponding to each pixel. Here, it is determined whether the detected illuminance is larger or smaller than the set value 1 (step 3). Then, if the detected illuminance is smaller than the set value 1, the intensity attenuation distribution table 1 is set in each pixel maximum luminance conversion table (step 4). On the other hand, if the detected illuminance is larger than the set value 1, it is determined whether the detected illuminance is larger or smaller than the set value N (step 5). If the detected illuminance is smaller than the set value N, the intensity attenuation distribution table N is set in each pixel maximum luminance conversion table (step 6). If the detected illuminance is larger than the set value N, the maximum uniform distribution table is set in the maximum luminance conversion table for each pixel (step 7), and the total total maximum luminance of the electroluminescent element 1 is set to a full lighting state. Is converted. Next, the set maximum luminance conversion table for each pixel is subjected to a conversion operation based on the image signal data input from the outside and the maximum luminance conversion table value corresponding to each pixel (step 8), so that a predetermined maximum luminance distribution is obtained. Is converted into a current pulse signal for driving and lighting the electroluminescent element (step 9), charges are injected into each pixel of the electroluminescent element, and light is emitted in a pattern corresponding to the image signal (step 10) and projected on a screen. Is what is done. When the power is turned off, the process ends (step 12). When the power is not turned off, the process returns to step 8 (step 11).
[0018]
On the other hand, the distribution of the N maximum luminance conversion tables prepared for each pixel has the lowest overall luminance when the detected ambient illuminance is the lowest, and the luminance distribution of the projection lens is such that the screen illuminance distribution is uniform. The table is a table that provides a distribution for correcting a decrease in the amount of off-axis transmitted light. The higher the detected ambient illuminance, the higher the overall luminance gradually, and the luminance distribution approaches a uniform and flat distribution. Further, as described above, when the environmental illuminance is high and is higher than the comparison value of the detected illuminance, the electroluminescent element 1 is set to the full lighting state at the maximum setting, and the luminance distribution is uniformly lit.
[0019]
In the present embodiment, the overall light emission luminance and the luminance distribution of the electroluminescent element 1 are controlled in multiple stages, but may be controlled in such a manner as to smoothly interlock with the detected environment illuminance, and The display mode may be automatically switched by a simple threshold value between the case where the detection environment illuminance is high and the case where the detection environment illuminance is low.
[0020]
Also, from the viewpoint of human visual characteristics, light adaptation and dark adaptation occur according to the brightness of the environment around the screen, so that when viewing a display image in a dark environment, the illuminance is darker than that in a bright environment. However, if the image is projected too brightly in a dark environment, the surrounding environment will be illuminated by the scattered light from the screen, and the immersion in the displayed image will be impaired. Problems can also occur. Considering human visual characteristics to the last, it is preferable to display and project an image in the visual dynamic range region including the brightness of the environment.
In addition, since a color adaptation reaction also occurs in human visual characteristics, the color temperature or color of the environmental illumination is different between when displaying an image under an incandescent light bulb environment and when displaying an image under a fluorescent light environment. Is different, the color of the ambient light is detected, and the luminance ratio of each electroluminescent element or each color pixel arranged in the electroluminescent element, which is responsible for three primary colors of red, green, and blue, is changed. It is also effective in converting the color reproduction state of a display image.
As described above, when performing dark image projection display in a dark environment, emphasis is placed on illuminance uniformity of the projected image, and further on color reproducibility, while, when performing bright image projection display in a bright environment, Emphasizing the brightness of the projected image is an effective means in terms of device quality.
[0021]
Next, the operation of low-luminance lighting in the deterioration of the photoelectric conversion efficiency of the electroluminescent device will be described.
[0022]
The organic electroluminescent phosphor used in the organic electroluminescent device is composed of a blue light emitter, a green light emitter, and a red light emitter, and each of the blue light emitters has a benzoxazole zinc complex, An aluminum quinolinol complex is used for the green light emitter, and DCM or the like is used for the red light emitter. Regarding the photoelectric conversion efficiency of each phosphor, there is a phosphor capable of obtaining light energy of 18.4 mW / cm ^{2 by} supplying a charge carrier of 100 mA / cm ^{2 in} an environment at room temperature of about 23 ° C., and 5000 cd / m ² in green color. The above radiation amount is obtained, and the half-time of the photoelectric conversion efficiency has a characteristic of several thousand hours. Here, when used as an image modulation element for direct light emission of a projection display device, since the light emission luminance is insufficient, it is necessary to inject more than 100 mA / cm ² of charge carriers for forming excitons. . As a result, the thermal energy in the phosphor light emitting layers of the electroluminescent elements 1 or 1R, 1G, and 1B increases, so that the probability that the organic phosphor as the electroluminescent material is excited to the activated state increases, The degradation of the photoelectric conversion efficiency is accelerated by causing the collapse of the phosphor organic molecules.
[0023]
Therefore, in this embodiment, the temperature of the electroluminescent element 1 or 1R, 1G, 1B is controlled to about 20 ° C. by the Peltier element 4 provided on the back of the electroluminescent element in macroscopic view of the entire electroluminescent element. Thus, the image illuminance is reduced in the image display projection on the screen 3 under the dark environment illumination, while maintaining the half-time of the photoelectric conversion efficiency in the case where the electroluminescent element is fully lit at the maximum light emission luminance of the whole at several thousand hours. By doing so, the amount of charge carriers injected into the electroluminescent device is reduced, the temperature rise of the device is suppressed, and the half-time of the photoelectric conversion efficiency is extended. When the image display illuminance in darkness is fully lit as a half value of the maximum light emission luminance value in a bright environment, a gap between the cooling surface of the Peltier element 4 and the electroluminescent phosphor layers of the electroluminescent elements 1 or 1R, 1G, and 1B is obtained. , The half-time of the photoelectric conversion efficiency is increased about three times. Therefore, assuming a half-use condition in a dark environment and a bright environment, the half-time of the photoelectric conversion efficiency is increased by a factor of 1.5 as compared with the case of full lighting at the maximum emission luminance value, and in the actual driving state of the projection display device. Since the displayed image is not always fully white and fully lit, the calorific value of the electroluminescent element is also suppressed. Taking this into consideration, assuming that the average value of the actual modulation amount is half of the maximum light emission luminance value, the effect of similarly increasing the half time of the photoelectric conversion efficiency by about three times due to the actual image display modulation factor is also obtained. Be expected. Therefore, by cooling the electroluminescent element to about 20 ° C., the photoelectric conversion efficiency is reduced to about a half time of about several thousand hours in the maximum emission luminance lighting state of the electroluminescent element. Assuming that the half-time of the photoelectric conversion efficiency when the electroluminescent element itself is fully lit in a 20 ° C. environment is 2000 hours, the half-time of the photoelectric conversion efficiency is 9000 hours in the actual use state of the device, which is about three times as much as the actual modulation factor. Is what you can do.
[0024]
【The invention's effect】
As described above, according to the present invention, the brightness of an environment illuminating an object such as a screen for projecting an image is detected, and in conjunction with the brightness of the environment, when the illumination environment is dark, electroluminescence is used. By reducing the maximum emission luminance distribution of each pixel arranged in the electroluminescent element so that the overall maximum emission luminance of the element is reduced and the illuminance distribution on a projection object such as a screen is uniform, the element is bright. In a use environment, a bright projected image is displayed, and in a dark use environment, the illuminance of the projected image is made uniform, and the power injected into the organic electroluminescent element is reduced to reduce the temperature of the electroluminescent element. By reducing the rise and slowing down the chemical change rate of the organic phosphor material, the deterioration of the photoelectric conversion efficiency is delayed, and the quality maintenance period of the projection display device is lengthened. .
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a main part of a projection display device according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a main part of a projection display device according to a second embodiment of the present invention. 3. Schematic diagrams of main parts of the electroluminescent device used in the first embodiment of the present invention ((a), (b))
FIG. 4 is a schematic view ((a), (b)) of a main part of an electroluminescent device used in a second embodiment of the present invention.
FIG. 5 is a flowchart illustrating a method for controlling the light emitting state of the electroluminescent device of the present invention.
REFERENCE SIGNS LIST 1 electroluminescent element 1R red electroluminescent element 1G electroluminescent element 1B emitting green color electroluminescent element 2 emitting blue color 2 projection lens 2 screen 3 Peltier element 4 blowing fan 5 multiplex prism 6 focusing lens Reference Signs List 7 photoelectric conversion sensor 8 controller 10 glass substrate 11 electroluminescent material emitting red light 12 electroluminescent material emitting green light 13 electroluminescent material emitting blue light 14 transparent thin film electrode 15 metal thin film electrode 16 hole transport layer 17 dielectric Multi-layer reflective half mirror

Claims (11)

An electroluminescent element having a plurality of individually modulatable pixels, and a projection display device that displays an image by projecting light emitted from each modulated pixel in the electroluminescent element onto an object by a projection lens,
A projection display device, wherein brightness of an environment illuminating the object is detected, and light emission brightness of an electroluminescent element is controlled in conjunction with the brightness of the environment. 2. The projection device according to claim 1, wherein the overall maximum light emission luminance of the electroluminescent element is reduced so that the amount of light projected by the projection lens onto the projection object decreases in conjunction with the decrease in the environmental brightness. 3. Type display device. In conjunction with the decrease in the environmental brightness, the distribution of the maximum emission luminance of each pixel arranged in the electroluminescent element is corrected so that the amount of light projected on the projection object by the projection lens becomes uniform throughout the projection area. The projection display device according to claim 1, wherein: 3. The device according to claim 1, further comprising a correction unit configured to correct a peak current value or a current pulse time width supplied to the electroluminescent element to correct the overall maximum emission luminance of the electroluminescent element. 4. Projection display device. Correction means for correcting the distribution of the maximum light emission luminance of each pixel disposed in the electroluminescent element by modulating the current pulse time width or peak current value supplied to each pixel in the electroluminescent element. The projection display device according to claim 1, wherein: 2. The projection display device according to claim 1, wherein the electroluminescent element is configured by a repetitive matrix arrangement of light-emitting pixels of three primary colors and displays an additive color mixture image. The three electroluminescent elements are arranged to emit three primary colors, and light emitted from the three electroluminescent elements is multiplexed by a prism having a dichroic wavelength band separation film disposed on a predetermined surface. 2. The projection display device according to claim 1, wherein after adding, the image is projected on an object by a projection lens to display an additive color mixture image. The electroluminescent element forms excitons by injecting charge carriers into a light emitting layer having a material containing an organic phosphor, and EL (electroluminescence) in which modulation pixels which emit light by recombination of the excitons are two-dimensionally arranged. 8. The projection display device according to claim 1, wherein the projection display device is a light emitting element. 9. The projection display device according to claim 8, wherein a resonance structure of generated photons is formed by the charge carrier injection electrode film of the EL light emitting element and a light reflection film disposed on an outer surface of the electrode film. 10. The projection display device according to claim 1, wherein the projection image is projected on a screen and can be recognized by diffuse reflection light having a predetermined directivity. 10. The projection display device according to claim 1, wherein the projection image is projected on a screen and can be recognized by diffuse transmission light having a predetermined directivity.

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