JP3698703B2 - projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projector, and more particularly to a projector that can improve the gradation recognition of an image, that is, can recognize the luminance level of the image with high accuracy.
[0002]
[Prior art]
A good projection environment of a projector, particularly a front projector, is to provide a highly reflective screen and darken the surroundings. In particular, when viewing images such as movies, black expression is important, and the contrast performance of the front projector itself, that is, the 100% all white pattern image and 100% defined by the Japan Business Machine Manufacturers Association Data Projector Subcommittee. Increasing the contrast ratio indicated by the luminance ratio of the all black pattern image is advancing. The high contrast ratio means that the black portion is observed darker and darker when the luminance of the image of the portion other than black is the same. As of October 2002, the projector having the highest contrast ratio is 2600: 1 of the projector VP-12S2 manufactured by Nippon Marantz Co., Ltd.
[0003]
The black part of the image projected on the white screen is brighter than the surrounding non-white object due to the fact that some light arrives from the projector and the difference in reflectance, no matter how much the brightness is reduced. Therefore, in the environment where the projection is actually performed, there is a problem that the black part of the image is recognized brighter than the non-white object such as the black frame part on the periphery of the screen, the wall surface, the chair, and the desk.
Furthermore, in a bright projection environment, there is a problem that the black portion of the projected image becomes higher than the original luminance due to the influence of ambient light.
[0004]
On the other hand, the projection environment cannot be completely darkened due to safety considerations and other aspects of daily life. Even if a complete dark room can be achieved, if the dark image continues, the eye glows and the amount of light increases or the sensitivity of the optic nerve increases. As a result, there is a problem that the screen that initially appeared black becomes gradually brighter.
[0005]
OBJECT OF THE INVENTION
The present invention has been made in view of the above-described problems relating to the projector of the prior art, and recognizes a dark area in the image as relatively black by providing a portion serving as a luminance reference around the image. It is an object of the present invention to provide a projector that can do this.
According to the present invention, even when the brightness of the black portion of the projected image is increased in a relatively bright projection environment, the presence of the relatively bright frame portion prevents the black portion from increasing even if the brightness of the black portion increases. It is an object to provide a projector that can be recognized as
The present invention also prevents a phenomenon in which the black portion of the image is felt bright due to the presence of the bright frame portion even when the luminance of the black portion of the projected image is sufficiently low in a relatively dark projection environment. An object of the present invention is to provide a projector that can
[0006]
[Means for Solving the Problems]
The present invention is characterized in that an image part is formed in the center of a projector projection area on a screen and projected so as to form a reference part having an average luminance of 10% to 30% of the maximum luminance of the image part at a peripheral part. It is a projector.
[0007]
Embodiments of the present invention are as follows.
The reference portion is a frame portion around the video portion. By comprising in this way, the effect of a reference | standard part can be heightened most. That is, it is said that human vision (cells) recognizes changes in light intensity more sensitively than light intensity itself, unlike an image sensor. That is, in order for a human to recognize an object, the position of the image formed on the retina is moved by constantly moving the eyeball, that is, the line of sight. When looking at the screen, the line of sight repeatedly moves from outside the projection area into the projection area, so the frame moves so that it passes through the reference portion when moving from outside the projection area to the projection area in any direction. It is desirable to be a part.
The brightness of the frame portion is variable. With this configuration, there is an advantage that the brightness of the frame portion can be optimally adjusted in consideration of the projection environment and the brightness of the projected image.
[0008]
The width of the frame portion is 1% or more of the width of the smaller vertical width of the video portion. If it is less than 1%, there is a problem that an effective luminance standard cannot be provided to the image observer.
The size of the frame portion is determined based on image size information included in the video signal. This configuration has an advantage that the width of the frame portion can be optimally adjusted in consideration of the image size.
The frame portion is formed outside an image formed by a video signal. Such a configuration has an advantage that the video signal can be used effectively.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the image by the projector of the first embodiment is provided with a frame portion 10 around the projected image 1. The width of the frame portion 10 is 1% or more of the smaller one of the vertical width and the horizontal width of the video 1. If less than 1%, the frame portion 10 cannot provide the viewer with a sufficiently strong brightness standard for the field of view. The luminance of the frame portion 10 is 50% or less of the maximum luminance of the video 1, and preferably 10% to 30%. When the luminance of the frame portion 10 exceeds 50% of the maximum luminance of the video image 1, the frame portion 10 becomes awkward and prevents the video image 1 from being concentrated.
[0010]
The relationship between the luminance of the frame portion 10 and the projection environment is high luminance so that the black portion of the video 1 can be clearly recognized when the projection environment is bright. When the projection environment is dark, the luminance is set high to prevent the black portion of the video 1 from being recognized brighter than the surroundings.
[0011]
As shown in FIG. 2, in the video by the projector of the second embodiment, the widths of the upper and lower frame portions 21 and 22 and the left and right frame portions 23 and 24 of the frame portion 20 that satisfy the same conditions as the first embodiment are different. In the case of the horizontally long image 1, the widths of the upper and lower frame portions 21 and 22 are made much wider than the widths of the left and right frame portions 23 and 24. By doing so, in addition to providing a strong luminance standard for video, it is possible to enhance the sense of wideness. Furthermore, the width of the wide upper frame portion 21 and the width of the wide lower frame portion 22 can be made different so that captions (captions) can be displayed on the wider side.
[0012]
As shown in FIG. 3, an image by the projector of the third embodiment is provided with a plurality of dark shaded portions 32 in a frame portion 30 that satisfies the same width condition as that of the first embodiment. The luminance of the frame portion 30 excluding the dark hatched portion 32 must satisfy the luminance condition of the first embodiment. In place of the dark diagonal line 32, a marble pattern, a wood grain pattern, or a repeating pattern of a mark can be provided. In that case, the average luminance of the frame portion 30 must satisfy the luminance condition of the first embodiment.
[0013]
In the projection signal circuit of the embodiment, as shown in the block diagram of FIG. 4, the video signal S output from an imaging tube (not shown) or the like is input to the A / D converter 104 and the video format determination unit 101. . When the video signal S is a digital signal, the A / D converter 104 is not provided.
[0014]
When an analog video signal is input, the video format discrimination unit 101 discriminates the period of the vertical / horizontal synchronization signal from the video signal S (video semiconductors having such a function are also commercially available), and digital video In the case of a signal, the period of the vertical / horizontal synchronization signal recorded in the signal header or the like is read. When the video signal S is an analog signal, the output of the video format discrimination unit 101 is input to the frame image creation unit 112 and input to the image expansion / contraction circuit unit 110 and the A / D converter 104. An image size signal is input to the image expansion / contraction circuit unit 110, and a synchronization signal is input to the A / D converter 104.
[0015]
The image expansion / contraction circuit unit 110 calculates the image expansion / contraction rate necessary for display on the display element 124 from the image size of the video signal S, expands / contracts the image size, and displays an image size image that can be displayed on the display element 1242 Output a signal. The frame image creation unit 112 forms image signals of the video frame portions 10, 20, and 30 outside the image expanded and contracted by the image expansion / contraction circuit unit 110. The frame image creating unit 112 is connected to an input unit 114 for inputting image frame dimensions and the like. Outputs from the image expansion / contraction circuit unit 110 and the frame image creation unit 112 are input to the keystone correction unit 120.
[0016]
The keystone correction unit 120 performs keystone correction on the incident video signal S, that is, correction of trapezoidal distortion of the video by oblique projection. The output from the keystone correction unit 120 is input to the display element 124 via the display element controller 122, and a predetermined image is projected on a screen (not shown).
[0017]
【The invention's effect】
According to the projector of the present invention, by providing a portion serving as a luminance reference around the video, it is possible to recognize a dark area in the video as relatively black.
According to the present invention, even when the luminance of the black portion of the image projected in a relatively bright projection environment increases, the luminance of the black portion increases due to the presence of a relatively brighter frame portion. Has the effect of being recognized as black.
Further, according to the present invention, even when the luminance of the black portion of the projected image is sufficiently low in a relatively dark projection environment, the phenomenon that the black portion of the image is felt bright due to the presence of the bright frame portion is prevented. It has the effect that can be done.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a video configuration by a projector according to a first embodiment of the invention.
FIG. 2 is a diagram illustrating the configuration of an image by a projector according to a second embodiment of the invention.
FIG. 3 is an explanatory diagram of the structure of an image by a projector according to a third embodiment of the invention.
FIG. 4 is a block diagram of a projection signal circuit of the projector according to the embodiment of the invention.
[Explanation of symbols]
S video signal 1 video 10 frame part 20 frame part 21 upper frame part 22 lower frame part 23 left frame part 24 right frame part 30 frame part 32 dark diagonal line 101 video format discrimination part 104 A / D converter 110 image expansion / contraction circuit part 112 frame Image creation unit 120 Keystone correction unit

Claims (8)

  A projector characterized in that an image portion is formed at the center of a projector projection area on a screen and a reference portion having an average luminance of 10% to 30% of the maximum luminance of the image portion is formed at a peripheral portion.   The projector according to claim 1, wherein the reference portion is a frame portion around the video portion.   The projector according to claim 2, wherein the brightness of the frame portion is variable.   The projector according to claim 2, wherein the width of the frame portion is 1% or more of the vertical width of the video portion.   The projector according to claim 2, wherein the size of the frame portion is determined based on image size information included in a video signal.   The projector according to claim 2, wherein the frame portion is formed outside an image formed by a video signal. The projector according to claim 2, wherein the width of the frame portion is different between the upper and lower frame portions and the left and right frame portions. The projector according to claim 2, wherein the frame portion is provided with any one of a plurality of dark shaded portions, a marble pattern, a wood grain pattern, and a repeated pattern of a mark.

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