JP2008301382A - Projection display - Google Patents

Abstract

In the case of cinema content in which the input video signal has a lot of black components, the larger the screen size projected on the screen, the brighter the area effect, and the lower the contrast than in a small area. An object of the present invention is to provide a projection display device such as a projector that can improve visual characteristics.
In a resize / cinema signal detection circuit 40, a difference between the outputs of an A / D converter 30 is detected to determine whether the content is cinema content. Also, when the horizontal / vertical synchronization signal selected by the input selector 26 is input and the vertical synchronization signal is 24 Hz ± 1 Hz, it is determined that the input video signal is cinema content, and projection defined in the on-screen menu is performed. Controls the brightness level on the screen according to the screen size.
[Selection] Figure 3

Description

  The present invention relates to a projection display device such as a projector that includes a light source, a display device such as a liquid crystal panel for displaying an input image signal, and a projection lens, and that enlarges and projects an image displayed on the display device on a screen. .

  In recent years, video contents such as DVDs and BDs (Blu-ray Discs) are enlarged and projected on a screen using a projection display device such as a projector and are often displayed on a large screen. Under such circumstances, most of the video content is cinema content. In the case of cinema content, performance such as the color gamut, gamma characteristic, and black luminance level of the projector is required to be very high.

  On the other hand, when projecting and displaying images with a projector, many of the projection lenses are zoom lenses, and the screen size projected on the screen can be easily changed from 40 inches to 200 inches at a slight projection distance. As the projection screen size increases, the brightness of the screen decreases.

  Therefore, many projectors are realized by performing optical or electrical correction so that the brightness is close to a constant with respect to the brightness inversely proportional to the screen size projected on the screen.

  For example, in Patent Document 1, a projection screen size detection unit and a signal correction circuit or a light source dimming circuit are provided. When the projection screen size is larger than the setting, the luminance is increased. When the projection screen size is smaller than the setting, the luminance is increased. To reduce the change in brightness.

Japanese Patent Application Laid-Open No. 2004-228561 discloses that contrast adjustment is performed by controlling the amplitude of a video signal in accordance with the projection screen size and room brightness.
JP-A-6-11687 Japanese Patent Laid-Open No. 2002-300498

  However, as human visual characteristics, the larger the screen, the brighter it feels due to its area effect, and the brightness on the black side feels brighter than the brightness felt in inverse proportion to the area (projection screen size). In many cases, the contrast is perceived to be relatively lower than in the case of a small area.

  In particular, in the case of video content that is enlarged and projected by a projector, if the content has a low average luminance level on the entire screen such as a movie, it is easily affected by the visual characteristics.

  In consideration of the above-described problems, the present invention, when the input video signal is a cinema content with a large black component, the larger the projection screen size, the brighter the area effect, and the more the relative relative to the small area. In particular, it is an object of the present invention to provide a projection display device such as a projector that can improve the visual characteristic that contrast is felt low.

  In order to achieve this object, a first aspect of the present invention is a projection display device that includes a display device for displaying an input image signal, a light source, and a projection lens, and projects an image displayed on the display device on a screen. The input image vertical synchronization signal detection means or the cinema signal detection means, and a projection screen size definition means for defining a screen size to be projected, the result of the vertical synchronization signal detection means or cinema signal detection means, The brightness level on the screen surface is controlled by the projection screen size defined by the projection screen size defining means.

  According to this configuration, when the large screen is displayed on the screen, the black level that humans feel bright can be seen with the same contrast feeling as when viewing on the small screen.

  According to a second aspect of the present invention, there is provided a projection display device that includes a display device for displaying an input image signal, a light source, and a projection lens, and projects an image displayed on the display device on a screen. A signal detection means or a cinema signal detection means; and a projection screen size detection means for detecting a screen size to be projected, the detection result by the vertical synchronization signal detection means or the cinema signal detection means, and the projection screen size detection means. The brightness level on the screen surface is controlled according to the projection screen size detected in step 1, and the projection screen size is automatically detected without being defined by humans. When the screen is displayed, the black level that humans feel bright can be seen with the same contrast as when viewing on a small screen Cormorant having an effect.

  According to a third aspect of the present invention, in the projection display device according to the first aspect, the projection screen size defining means defines a screen size to be projected from a setting menu by on-screen display, Since it is not necessary to separately configure hardware such as a sensor for detecting the projection screen size, it has an effect of realizing a contrast feeling at low cost.

  According to a fourth aspect of the present invention, in the projection display device according to claim 2, the projection screen size detecting means detects the zoom position and the focus position of the projection lens, and the screen is projected on the screen with high accuracy. It has the function of automatically detecting the size.

  According to a fifth aspect of the present invention, in the projection display device according to claim 1 or 2, the vertical synchronization signal detection means is a frequency detection of 24 Hz, and the cinema signal detection means detects 2: 3 pull-down. Therefore, it is possible to automatically determine that the input video signal is cinema content.

  According to a sixth aspect of the present invention, in the projection display device according to claim 1 or 2, the projection screen size defined by the projection screen size defining means, the projection screen size detected by the projection screen size detecting means, and the cinema When cinema content is displayed larger than a predetermined projection screen size based on the cinema signal detection result of the signal detection means, the luminance level on the screen surface is set lower than the black level that is inversely proportional to the area. In the case of cinema content with a large black component in the input video signal, as the screen size projected on the screen increases, the brightness level is controlled so that the black level is lower than the brightness felt in inverse proportion to the area. As the large screen is displayed on the screen, the black level that humans feel bright is seen on the small screen. It has an effect that can be seen in the same contrast sense of time.

  As described above, when the input video signal is cinema content having a large black component, the projection display apparatus of the present invention has a black level that is higher than the brightness that is felt in inverse proportion to the area as the screen size projected on the screen increases. Since the brightness level is controlled so as to reduce the brightness, the black level that humans feel brighter due to the area effect can be seen with the same contrast as when viewing on a small screen when displaying on a large screen.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(Embodiment 1)
1 is an optical configuration diagram of a liquid crystal projector that is a projection display device according to a first embodiment of the present invention, FIG. 2 is an external view of the liquid crystal projector, and FIG. 3 is a detailed block diagram of an internal circuit.

  In FIG. 1, the image projected from the projection lens 119 of the projector 100 is displayed on liquid crystal panels (LCD: Liquid Crystal Display) 91, 92, 93 for R (red), G (green), and B (blue). The image is enlarged and projected on a screen (not shown) by the light from the lamp of the light source 117.

  The lamp lighting circuit 94 is controlled by the microcomputer 70 to turn on the light source 117. The light from the light source 117 is converted into light that is uniform on the liquid crystal panels 91, 92, and 93 by the first lens array 110 and the second lens array 111, and then decomposed into R, G, and B by the dichroic mirror 115. Then, the light enters the liquid crystal panels 91, 92, 93.

  Since the light path length of the light to the red liquid crystal panel 91 is different from those of the other green liquid crystal panel 92 and blue liquid crystal panel 93, the magnification is adjusted by the relay lens 116.

  There is a light amount stop 112 between the first lens array 110 and the second lens array 111, and the angle is adjusted by the light amount stop mechanism 113.

  Further, a color correction filter 114 for cutting yellow and cyan wavelengths is disposed between the second lens array 111 and the dichroic mirror 115.

  Further, a fan 118 for cooling the liquid crystal panels 91, 92, 93 is disposed below the liquid crystal panels 91, 92, 93.

  In FIG. 2, the projector 100 processes the input video signal and presses the POWER button 15 to enlarge and project from the projection lens 119 using the internal light source 117 and the liquid crystal panels 91, 92, and 93 shown in FIG. 1. Output video.

  As inputs, it has a VIDEO terminal 11, an S-VIDEO terminal 12, and an RGB / YPbPr terminal 13, each of which is connected to an external device. Also, a mouse port such as a USB is provided, and the mouse 16 is connected to operate as a setting state of the projector 100 and a pointer that can move on the screen. This also realizes the same function with the operation button 14.

  Further, in FIG. 3, a VIDEO terminal 11 is a terminal for inputting an NTSC composite video signal.

  The S-VIDEO terminal 12 is a terminal for inputting an S video signal.

  The RGB / YPbPr terminal 13 is a terminal for inputting an RGB signal or a YPbPr signal.

  The input selector 21 is a selector for selecting one of the composite video signal input from the VIDEO terminal 11 and the S video signal input from the S-VIDEO terminal 12.

  The Y / C separation circuit 23 is a circuit for separating the composite video signal input by the color decoder 22 into a Y signal and a C signal.

  The color decoder 22 is a decoder for color-decoding a Y / C separated signal or an inputted Y / C signal into a YPbPr signal.

  The matrix circuit 24 is a circuit for performing matrix processing when converting a YPbPr signal input from the RGB / YPbPr terminal 13 into an RGB signal.

  The input selector 25 is a selector for selecting one of the RGB signals input from the RGB / YPbPr terminal 13 and the RGB signals generated by the matrix circuit 24.

  The input selector 26 is a selector for selecting any analog signal from the YPbPr signal generated by the color decoder 22 and the RGB signal input by the input selector 25.

  The A / D converter 30 is a converter for A / D converting the analog signal selected by the input selector 26 into an 8-bit digital signal.

  The resize / cinema signal detection circuit 40 performs 2: 3 pull-down detection or 2: 2 pull-down detection from the digital signal A / D converted by the A / D converter 30 to determine whether the input video signal is cinema content. judge. Furthermore, it is a circuit for resizing according to the number of pixels of the liquid crystal panels 91 to 93 and superimposing the on-screen.

  The color conversion circuit 50 is a circuit that converts RGB data output from the resize / cinema signal detection circuit 40 into a predetermined color.

  The microcomputer 70 performs all control of the entire apparatus, such as power control, fan control, temperature control, angle control of the light quantity diaphragm mechanism 113, insertion control of the color correction filter 114, input switching control, voltage control of the lamp lighting circuit 94, and the like. In addition, it has a function of detecting the screen size projected on the screen based on the position information of the lens sensor 120.

  The digital phase expansion circuits 81 to 83 are circuits for phase expansion of the digital signal color-corrected by the color conversion circuit 50 in consideration of the operation speed of drive drivers (not shown) of the liquid crystal panels 91 to 93.

  A panel driving IC (Integrated Circuit) 90 is a circuit for driving the liquid crystal panels 91 to 93.

  The liquid crystal panels 91 to 93 are panels for color-displaying digital signals color-corrected by the color conversion circuit 50 and phase-developed by the digital phase development circuits 81 to 83.

  An operation for controlling the luminance level in such a configuration will be described.

  FIG. 4 is a circuit block diagram in the resize / cinema signal detection circuit 40.

  First, the output of the A / D converter 30 is stored in the field memories 41 and 42, the frame difference is detected by the subtractor 43, and the difference is detected by the telecine conversion signal detection unit 44 over five fields, so that the cinema. It is determined whether it is content.

  From the input interlaced video signal, an optimum interpolated video signal is generated by the switches 45 and 46 based on the detection result, thereby realizing a progressive video.

  At this time, if it is determined that the content is not cinema content, the 2-line interpolation unit 48 performs 2-line interpolation processing with the line memory 47 in the current field, and the operation unit 49 sequentially performs the current signal. And an interpolated signal are alternately output to output a progressive signal.

  The horizontal / vertical synchronization signal selected by the input selector 26 is input to the resize / cinema signal detection circuit 40.

  At this time, even when the vertical synchronization signal is 24 Hz ± 1 Hz, the input video signal determines cinema content.

  If any of the vertical synchronization signal is 24 Hz and 2: 3 pull-down detection is detected as cinema content, the determination is utilized.

  With respect to the definition of the screen size projected on the screen, an image adjustment menu as shown in FIG. 5 is displayed on the on-screen menu superimposed by the resize / cinema signal detection circuit 40, and the projection screen size is selected therein. In the example shown, 80 inches is selected.

  Based on the projection screen size definition and the cinema signal detection determination result, when the projection screen size is larger than 60 inches and cinema content is displayed, it is displayed below the black level that is inversely proportional to the area.

Specifically, as shown in FIG. 6, when the screen brightness at the black level of 60 inches is 4 cd / m ² , the area is usually quadrupled at, for example, 120 inches. Is 1 cd / m ² , but the brightness of 1 cd / m ² or more is felt due to the area effect, so that a contrast cannot be obtained. Therefore, in this case, by adjusting the black level so as to be 0.7 cd / m ² and outputting it, it becomes possible to feel the contrast as high as 60 inches.

  As a method for adjusting the black level, the black level is controlled by reducing the light amount stop 112 or lowering the voltage of the lamp lighting circuit 94 when the average luminance level is lowered by the histogram of the video signal of the entire screen. .

  As described above, in black level control, the vertical sync signal detection or cinema signal detection of the input image and the screen size to be projected are defined on the screen, and in the case of cinema content with many black components, it is projected on the screen. As the screen size increases, the brightness level is controlled so that the black level is lower than the brightness felt in inverse proportion to the area, and the contrast is increased to increase the black level that humans feel brighter on a small screen. It can be seen as the same contrast as when looking.

(Embodiment 2)
In the liquid crystal projector that is the projection display device according to the second embodiment of the present invention, the internal configuration of the projector is as shown in FIGS. 1, 2, and 3 in the first embodiment, and the basic operation is the same as in the first embodiment. It is.

  The difference from the first embodiment is that the human selects the definition of the screen size projected on the screen on-screen, but in this embodiment, the zoom drive motor attached to the projection lens 119, the focus The screen size projected on the screen is automatically determined according to the rotation position of the adjustment motor.

  In such a configuration, when the vertical synchronization signal of the input video signal is determined to be 24 Hz or the input interlace signal is determined to be a 2: 3 pull-down signal, the result of detecting the screen size projected on the screen is from 60 inches. If it is larger, the contrast level is the same as when viewing at 60 inches by lowering the black level inversely proportional to the area and increasing the contrast.

  The liquid crystal projector of the present invention described above is lower than the black level that is inversely proportional to the area when the projection screen size is larger than 60 inches in the first and second embodiments. When the tone is set at 40 inches or 80 inches, it is necessary to set the black level from that size.

  Further, the black level of a size larger than that of 60 inches is shown in FIG. 6, but it is preferable to increase the black level and lower the contrast for the portion of 60 inches or less. Since the area effect is unlikely to occur at a viewing distance (screen height × 2 to 3 times) normally viewed by humans, no processing is required.

  The means for detecting the screen size projected on the screen is not limited to the above, and may be detected by mounting a CCD camera, or the distance measured by the sensor and the gear position of the zoom lens. The screen size projected on the screen in combination may be obtained.

  In each embodiment, the cinema signal detection in the interlace signal is detected from the frame difference by the 2: 3 pull-down signal. However, the detection may be performed by the 2: 2 pull-down such as the PAL signal or by the presence / absence of the letter box. It is not particularly limited as long as it has a discrimination signal or signal form for detecting that it is cinema content.

  In each of the above embodiments, a liquid crystal projector is exemplified as the projection display device. However, the present invention is not limited to this, and it is needless to say that another display device such as a DLP method may be used.

  The projection display device according to the present invention has an effect that when displaying a large screen on a screen, a black level that a human feels bright due to the area effect can be seen with the same contrast feeling as when viewing on a small screen, It is suitable for image display applications for displaying cinema content video signals such as DVD and BD.

1 is an optical configuration diagram of a liquid crystal projector according to first and second embodiments of the present invention. 1 is an external view of a liquid crystal projector according to Embodiments 1 and 2 of the present invention. Circuit block diagram of liquid crystal projector according to first and second embodiments of the present invention FIG. 3 is a circuit block diagram in the resize / cinema signal detection circuit of the liquid crystal projector according to the first embodiment of the present invention. The figure which shows the on-screen menu of the liquid crystal projector of Embodiment 1 of this invention. The graph which shows the brightness | luminance of the black level with respect to the projection screen size of the liquid crystal projector of Embodiment 1, 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 VIDEO terminal 12 S-VIDEO terminal 13 RGB / YPbPr terminal 14 Operation button 15 POWER button 16 Mouse 21 Input selector 22 Color decoder 23 Y / C separation circuit 24 Matrix circuit 25 Input selector 26 Input selector 30 A / D converter 40 Resize Cinema signal detection circuit 50 Color conversion circuit 70 Microcomputer 81-83 Digital phase expansion circuit 90 Panel drive IC
91 to 93 Liquid crystal panel 100 Projector 110 First lens array 111 Second lens array 112 Light quantity stop 113 Light quantity stop mechanism 114 Color correction filter 115 Dichroic mirror 116 Relay lens 117 Light source 118 Fan 119 Projection lens

Claims (6)

In a projection display apparatus that includes a display device for displaying an input image signal, a light source, and a projection lens, and projects an image displayed on the display device on a screen.
Vertical sync signal detection means or cinema signal detection means of the input image;
A projection screen size defining means for defining a screen size to be projected,
A projection type display device characterized in that the brightness level on the screen surface is controlled by the detection result by the vertical synchronization signal detection means or the cinema signal detection means and the projection screen size defined by the projection screen size definition means. . In a projection display apparatus that includes a display device for displaying an input image signal, a light source, and a projection lens, and projects an image displayed on the display device on a screen.
Vertical sync signal detection means or cinema signal detection means of the input image;
A projection screen size detecting means for detecting a screen size to be projected,
A projection display device, wherein a luminance level on the screen surface is controlled based on a detection result by the vertical synchronization signal detection unit or the cinema signal detection unit and a projection screen size detected by the projection screen size detection unit. . 2. The projection display device according to claim 1, wherein the projection screen size defining means defines a screen size to be projected from a setting menu by on-screen display. 3. The projection display device according to claim 2, wherein the projection screen size detecting unit detects a screen size to be projected based on a zoom position and a focus position of the projection lens. 3. The projection display device according to claim 1, wherein the vertical synchronizing signal detection means is frequency detection of 24 Hz, and the cinema signal detection means performs 2: 3 pull-down detection. Cinema content larger than a predetermined projection screen size based on the projection screen size defined by the projection screen size definition means or the projection screen size detected by the projection screen size detection means and the cinema signal detection result of the cinema signal detection means 3. The projection display device according to claim 1, wherein the brightness level on the screen surface is lower than a black level that is inversely proportional to the area.