The present application claims priority under 35 U.S.C. 119 to Japanese Patent Application No. 2014-210327 filed Oct. 14, 2014. The contents of that application are incorporated herein by reference in their entirety.
1. Field of the Invention
The present disclosure relates to a light emitting apparatus provided with light emitting elements such as light emitting diodes (LEDs) or laser diodes (LDs) appropriate for use as a general-purpose image display device. The present disclosure also relates to the display section and controller circuit components of the light emitting apparatus.
2. Description of the Related Art
Currently, high luminosity light emitting elements such as LEDs and LDs have been developed to emit all of the three primary colors: red, green, and blue (RGB). This has made it possible to make large screen, full-color, self-emitting (i.e. not backlight dependent) displays. Among the newly developed displays, LED displays feature attributes including light weight, thin outline, and high luminosity with low power consumption. Accordingly, there is rapidly increasing demand for large screen LED displays that can be used outdoors as well as indoors. Demand has also developed, from a price-performance standpoint, for displays that support high-resolution while restraining the number of light emitting elements employed.
International patent disclosure WO 00/057398 describes a display section that is representative of those used in related art image display applications.
If red light emitting elements 20a (designated first light emitting elements 20a) are focused on, each red light emitting element 20a is disposed at the center of four adjacent grid-points 21 as shown in
Next, as shown in
Subsequently, as shown in
In the system described above, all the input display data corresponding to the grid-points 21 are output to the light emitting elements 20a, 20b, 20c by control that is implemented as a function of time. Pixel groups 23-31, which are activated with intervening time increments, overlap in both the horizontal and vertical directions. Since light emission in these pixel overlap regions becomes averaged in time, reduced image resolution arises in the both horizontal and vertical directions.
The present invention was developed to resolve this type of problem. Thus, it is an object of the present invention to provide a light emitting apparatus, display section, and controller circuit that increase resolution while reducing the number of light emitting elements employed.
To achieve the object cited above, one light emitting apparatus of the present invention is provided with a display section having a plurality of light emitting elements disposed in a matrix array, and a controller circuit that controls activation (illumination) of the light emitting elements in accordance with input data corresponding to the image to be displayed by the display section. First light emitting elements, second light emitting elements, and third light emitting elements are provided to emit the three primary colors. The display matrix is made up of a plurality of grid-points; second light emitting elements and third light emitting elements are disposed at grid-points in four directions adjacent to each grid-point where a first light emitting element is disposed; and each second light emitting element and third light emitting element is disposed at a common grid-point. The controller circuit samples input data at each grid-point to generate display data that activate each light emitting element; controls first light emitting element activation based on first light emitting element color information contained in first display data, which are display data sampled at each grid-point where a first light emitting element is disposed; controls second light emitting element activation based on second light emitting element color information contained in second display data, which are display data sampled at each grid-point where a second and third light emitting element is disposed; and controls third light emitting element activation based on third light emitting element color information contained in the second display data.
With this system, a high resolution light emitting apparatus can be realized even when the number of light emitting elements is restrained. For example, compared to a scheme where first, second, and third light emitting elements comprising the three primary colors are disposed as a unit at each grid-point and input data is sampled at each grid-point, the system described above can achieve the same degree of resolution with a display section employing half the number of light emitting elements.
More complete appreciation of the invention and many of its attendant advantages will be readily obtained as the invention becomes better understood by reference to the subsequent detailed description considered in conjunction with the accompanying drawings.
The following describes embodiments of the present invention with reference to the accompanying drawings. Here, similar reference numbers designate corresponding or identical components in the drawings. However, the following light emitting apparatus descriptions are merely specific examples representative of the technology associated with the present invention, and in the absence of specific annotation, the present invention is not limited to implementations described below. Further, content used to describe one implementation or embodiment may also be applied to describe other implementations or embodiments. Properties such as the size and spatial relation of components shown in the figures may be exaggerated for the purpose of clear explanation.
The following describes implementation of a light emitting apparatus for the present first embodiment based on
The display matrix 3 is made up of a plurality of grid-points 21. Second light emitting elements 2b and third light emitting elements 2c are disposed at grid-points in four directions next to each grid-point where a first light emitting element 2a is disposed, and second light emitting elements 2b and third light emitting elements 2c are disposed at common grid-points. As shown in
First light emitting elements 2a and second and third light emitting elements 2b, 2c are disposed with a pitch (distance between elements) of x0 in the x-direction and a pitch of y0 in the y-direction. In
The controller circuit 4 samples input data for each grid-point in the display section 3 matrix and generates display data to activate (illuminate) each light emitting element. Here, display data are the information necessary to illuminate each light emitting element and include parameters such as element luminosity, brightness, and current flow.
Data sampling grid-points are not established in between RGB light emitting element locations as in layouts such as shown in
The controller circuit 4 performs illumination control of first light emitting elements 2a according to first light emitting element 2a color information contained in first display data, which are display data sampled at grid-points where first light emitting elements are disposed. The controller circuit 4 also performs illumination control of second and third light emitting elements 2b, 2c according to second light emitting element 2b color information and third light emitting element 2c color information contained in second display data, which are display data sampled at each grid-point where a second and third light emitting element is disposed.
While each emission color of the first, second, and third light emitting elements 2a, 2b, 2c, which establish the three primary colors, can be formed by any combination of colors, it is preferable for the peak emission wavelengths of the second and third light emitting elements 2b, 2c to both be either shorter or longer than the peak emission wavelength of the first light emitting element 2a. Specifically, first light emitting elements 2a are either red or blue. This enables realization of a light emitting apparatus with superior color mixing capability. In the present embodiment, first light emitting elements 2a are red, and second light emitting elements 2b are either blue or green. When the emission color of second light emitting elements 2b is blue, third light emitting elements 2c emit green light, and when the emission color of second light emitting elements 2b is green, third light emitting elements 2c emit blue light.
In the comparison example as well, the controller circuit 4 samples input data for each grid-point in the display section 6 matrix and generates display data to activate (illuminate) each light emitting element. In this case, the display data are sampled at each grid-point, and a light emitting element group that includes a first light emitting element 7a, second light emitting element 7b, and third light emitting element 7c is disposed at each grid-point. From that data, the controller circuit 4 controls illumination of first light emitting elements 7a located at each grid-point based on first light emitting element 7a color information, controls illumination of second light emitting elements 7b located at each grid-point based on second light emitting element 7b color information, and controls illumination of third light emitting elements 7c located at each grid-point based on third light emitting element 7c color information.
In the comparison example represented in
In the light emitting apparatus of the present embodiment represented in
While the light emitting apparatus for the comparison example has a group of light emitting elements 7a, 7b, 7c that emit the three primary colors disposed at each grid-point, the light emitting apparatus of the present embodiment has fewer light emitting elements (light emitting element population is thinned out), and that results in the color-distortion region 13. Since the color-distortion region 13 is outside the four sides 12 (but not including the corner points) of the true-color region 11, color balance is not maintained and color-distortion can result when the spatial frequency of an image obliquely inclined with respect to the x and y-axes is high. However, the spatial frequency domain has a true-color region 11 that includes points at ±½x0 and ±½y0 on the μ and ν axes, and horizontal direction (x-direction) and vertical direction (y-direction) images have the same resolution as those displayed by the comparison example light emitting apparatus.
Red color emitted by first light emitting elements 2a is complementary to mixed blue and green colors emitted by the second and third light emitting elements 2b, 2c. Accordingly, even grid-points disposed with an x-direction spatial frequency μ at the ½x0 point maintain color balance and can render white straight-lines. Similarly grid-points disposed with a y-direction spatial frequency ν at the ½y0 point also maintain color balance and can display white straight-lines. Compared to the light emitting apparatus of the comparison example shown in
The following describes the second embodiment of the present invention with reference to appropriate figures. As shown in
First, the first light emitting element 2a disposed at the first grid-point (2, 2) is illuminated based on first light emitting element 2a color information included in first display data sampled at the first grid-point (2, 2). In addition, the second light emitting element 2b disposed at the second grid-point (1, 2) is illuminated based on second light emitting element 2b color information included in second display data sampled at the second grid-point (1, 2), and the third light emitting element 2c disposed at the second grid-point (1, 2) is illuminated based on third light emitting element 2c color information included in the second display data sampled at the second grid-point (1, 2). Light emitting elements disposed at the other second grid-points (2, 1), (2, 3), (3, 2) are illuminated in a similar manner. Specifically, the second light emitting element 2b disposed at the second grid-point (2, 1) is illuminated based on second light emitting element 2b color information included in second display data sampled at the second grid-point (2, 1), and the third light emitting element 2c disposed at the second grid-point (2, 1) is illuminated based on third light emitting element 2c color information included in the second display data sampled at the second grid-point (2, 1). The second light emitting element 2b disposed at the second grid-point (2, 3) is illuminated based on second light emitting element 2b color information included in second display data sampled at the second grid-point (2, 3), and the third light emitting element 2c disposed at the second grid-point (2, 3) is illuminated based on third light emitting element 2c color information included in the second display data sampled at the second grid-point (2, 3). Further, the second light emitting element 2b disposed at the second grid-point (3, 2) is illuminated based on second light emitting element 2b color information included in second display data sampled at the second grid-point (3, 2), and the third light emitting element 2c disposed at the second grid-point (3, 2) is illuminated based on third light emitting element 2c color information included in the second display data sampled at the second grid-point (3, 2). The control procedure described in this paragraph is referred to below as the “first control operation.”
Subsequently, the second light emitting element 2b disposed at the second grid-point (1, 2) is illuminated based on second light emitting element 2b color information included in the first display data sampled at the first grid-point (2, 2), and the third light emitting element 2c disposed at the second grid-point (1, 2) is illuminated based on third light emitting element 2c color information included in the first display data sampled at the first grid-point (2, 2). In addition, the first light emitting element 2a disposed at the first grid-point (2, 2) is illuminated based on first light emitting element 2a color information included in the second display data sampled at the second grid-point (1, 2). Similar illumination control is performed at the other second grid-points (2, 1), (2, 3), (3, 2). Specifically, the second light emitting element 2b disposed at the second grid-point (2, 1) is illuminated based on second light emitting element 2b color information included in the first display data sampled at the first grid-point (2, 2), and the third light emitting element 2c disposed at the second grid-point (2, 1) is illuminated based on third light emitting element 2c color information included in the first display data sampled at the first grid-point (2, 2). The first light emitting element 2a disposed at the first grid-point (2, 2) is illuminated based on first light emitting element 2a color information included in the second display data sampled at the second grid-point (2, 1). The second light emitting element 2b disposed at the second grid-point (2, 3) is illuminated based on second light emitting element 2b color information included in the first display data sampled at the first grid-point (2, 2), and the third light emitting element 2c disposed at the second grid-point (2, 3) is illuminated based on third light emitting element 2c color information included in the first display data sampled at the first grid-point (2, 2). The first light emitting element 2a disposed at the first grid-point (2, 2) is illuminated based on first light emitting element 2a color information included in the second display data sampled at the second grid-point (2, 3). Further, the second light emitting element 2b disposed at the second grid-point (3, 2) is illuminated based on second light emitting element 2b color information included in the first display data sampled at the first grid-point (2, 2), and the third light emitting element 2c disposed at the second grid-point (3, 2) is illuminated based on third light emitting element 2c color information included in the first display data sampled at the first grid-point (2, 2). Still further, the first light emitting element 2a disposed at the first grid-point (2, 2) is illuminated based on first light emitting element 2a color information included in the second display data sampled at the second grid-point (3, 2). The control procedure described in this paragraph is subsequently referred to as the “second control operation.”
Since no second or third light emitting elements 2b, 2c are disposed at the first grid-point (2, 2), illumination at the first grid-point (2, 2) based on second light emitting element 2b color information or third light emitting element 2c color information included in the first display data sampled at the first grid-point (2, 2) is not possible. However, that color information can be used to illuminate second and third light emitting elements 2b, 2c disposed at second grid-points (1, 2), (2, 1), (2, 3), (3, 2), which are adjacent to the first grid-point (2, 2). Similarly, since no first light emitting element 2a is disposed at the second grid-point (1, 2), illumination at the second grid-point (1, 2) based on first light emitting element 2a color information included in the second display data sampled at the second grid-point (1, 2) is not possible. However, that color information can be used to illuminate the first light emitting element 2a disposed at the first grid-point (2, 2), which is adjacent to the second grid-point (1, 2). More generally, that color information can be used to illuminate first light emitting elements 2a disposed at adjacent first grid-points (2, 2), (0, 2), (1, 1), (1, 3), which are to the right, left, above, and below the second grid-point (1, 2). First light emitting element 2a color information included in second display data at the other second grid-points (2, 1), (2, 3), (3, 2) can be used in the same manner (to illuminate adjacent first light emitting elements 2a).
By implementing these control procedures, off-color effects occurring in the color-distortion region 13 of the second embodiment can be suppressed and color balance can be improved.
The first light emitting element 2a disposed at the first grid-point can be grouped with at least one or more of the second and third light emitting elements 2b, 2c disposed at the four adjacent second grid-points. However, as described above, grouping the first light emitting element 2a disposed at the first grid-point with second and third light emitting elements 2b, 2c disposed at all four adjacent second grid-points is more effective and desirable for suppressing off-color effects occurring in the color-distortion region 13 and improving color balance.
In the “first control operation” and “second control operation” described above, the second and third light emitting elements 2b, 2c disposed at the second grid-point (1, 2), the second and third light emitting elements 2b, 2c disposed at the second grid-point (2, 1), the second and third light emitting elements 2b, 2c disposed at the second grid-point (2, 3), and the second and third light emitting elements 2b, 2c disposed at the second grid-point (3, 2) can be illuminated in a random order or simultaneously after illuminating the first light emitting element 2a disposed at the first grid-point (2, 2). Or, the first light emitting element 2a disposed at the first grid-point (2, 2), the second and third light emitting elements 2b, 2c disposed at the second grid-point (1, 2), the second and third light emitting elements 2b, 2c disposed at the second grid-point (2, 1), the second and third light emitting elements 2b, 2c disposed at the second grid-point (2, 3), and the second and third light emitting elements 2b, 2c disposed at the second grid-point (3, 2) can be all be illuminated simultaneously.
Although the “first control operation” is performed after the “second control operation” in the present embodiment, the system is not limited to that sequence and the “first control operation” and “second control operation” can also be performed simultaneously.
When the light emitting element controller circuit generates display data from input data sampled at grid-points in the manner described above, images based on the input data can be displayed without compromising image resolution even when a reduced number of light emitting elements are employed.
Note that examples described above employ additive color scheme RGB color emission from the first light emitting elements, second light emitting elements, and third light emitting elements. However, subtractive color scheme cyan, yellow, magenta (CYM) colors can also be employed.
The light emitting apparatus, display section, and controller circuit of the present invention can be used with good results in devices such as display devices that display stationary or moving images using LEDs. In addition, the present invention can also be used in “intelligent lighting” applications, which provide dynamic lighting that can change colors using input data that include lighting color information. In that respect, the term “image” used in the present application can have a broader meaning to also include “lighting” and its color specifying data.
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