Image display
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorIsao Kawahara
Life of this patent
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Abstract
An image display apparatus using a display panel such as a plasma display panel having two illumination states aims to widen a dynamic range by increasing a ratio of maximum to minimum luminance reproducible on the same screen. In the image display apparatus, one TV field period is divided into a plurality of sub-fields which respectively have luminance weights and are arranged in order of time, and a gray-scale image is displayed by selecting a combination of sub-fields for each pixel and sustaining a light emission state of each pixel during the selected sub-fields, wherein when arranged in ascending order of luminance weight, the plurality of sub-fields include at least one sub-field whose luminance weight is one-half of a luminance weight of the next sub-field.
Claims15
An image display apparatus, in which one TV field period is divided into a plurality of sub-fields that are each given a different luminance weight and are arranged in ascending or descending order of luminance weight, when S denotes a sum of luminance weights of the plurality of sub-fields and R is within a range from 0 to S, a gray level corresponding to R is expressed by selecting sub-fields whose luminance weights, when added together, are closest to R, characterized in that when the plurality of sub-fields are arranged in ascending order of luminance weight with the ith smallest luminance weight being denoted by Wi, “n” exists such that W1+W1+W2+ . . . . . . . . +Wn<Wn+1, where 1≦n and n+1≦the number of the plurality of sub-fields.
An image display apparatus, in which one TV field period is divided into a plurality of sub-fields that are each given a luminance weight and are arranged in order of time, and a gray-scale image for the TV field period is displayed by choosing one of a plurality of coding patterns which are each made up of a combination of sub-fields having predetermined luminance weights in accordance with a maximum gray level of an input image signal and illuminating each pixel during desired sub-fields using the chosen coding pattern, where maximum display luminance is controlled according to a characteristic of the input image signal, characterized in that
- when a ratio of a sum of luminance weights of all sub-fields in a first coding pattern to a sum of luminance weights of all sub-fields in a second coding pattern is denoted by K, where the first and second coding patterns are included in the plurality of coding patterns and the sub-fields in the first coding pattern are in a one-to-one correspondence with the sub-fields in the second coding pattern in order of luminance weight, the sub-fields in the first coding pattern include:
- (a) a sub-field having a luminance weight whose ratio to a luminance weight of a corresponding sub-field in the second coding pattern is less than or equal to a value K, and
- (b) a sub-field having a luminance weight whose ratio to a luminance weight of a corresponding sub-fields in the second coding pattern is greater than the value K.
A method for representing display field information comprising:
- dividing one TV field period into a plurality of sub-fields that are each given a luminance weight and are arranged in order of time;
- displaying a gray-scale image for the TV field period by choosing one of a plurality of coding patterns which are each made up of a combination of sub-fields having predetermined luminance weights in accordance with a maximum gray level of an input image signal;
- illuminating each pixel during desired sub-fields using the chosen coding pattern, where maximum display luminance is controlled according to a characteristic of the input image signal, characterized in that
- when a ratio of a sum of luminance weights of all sub-fields in a first coding pattern to a sum of luminance weights of all sub-fields in a second coding pattern is denoted by K, where the first and second coding patterns are included in the plurality of coding patterns and the sub-fields in the first coding pattern are in a one-to-one correspondence with the sub-fields in the second coding pattern in order of luminance weight, the sub-fields in the first coding pattern include:
- (a) a sub-field having a luminance weight whose ratio to a luminance weight of a corresponding sub-field in the second coding pattern is less than or equal to a value K, and
- (b) a sub-field having a luminance weight whose ratio to a luminance weight of a corresponding sub-fields in the second coding pattern is greater than the value K.
Dependencies are inferred from the claim text.