The present application relates to an image display panel, an image display device, and a manufacturing method for the image display panel and can be suitably applied to an active matrix image display device employing self-light emitting elements such as organic EL elements. In the present application, monitoring light is emitted from a self-light emitting element for monitoring used for luminance adjustment to an opposite side of a side to which a self-light emitting element for image display emits light, whereby restrictions on housing design are reduced compared with those in the past and deterioration in an image quality is prevented.
In recent years, the development of an active matrix image display device employing organic EL elements is actively performed. The organic EL elements are self-light emitting elements of a current driving type, light emission luminance L of which is represented by light emission efficiency Φ and a driving current I. In the active matrix image display device employing the organic EL elements, pixel circuits including the organic EL elements and driving circuits that drive the organic EL elements are arranged in a matrix shape to form an image display unit. A desired image is displayed on the image display unit.
However, light emission efficiency of the organic EL elements falls more as light emission luminance is higher or the organic EL elements are used for a longer time. As a result, when the image display device employing the organic EL elements displays a still image having large contrast for a long time, so-called burn-in and a change in chromaticity occurs. Further, luminance changes because of aged deterioration. Therefore, for example, JP-A-2007-156044 discloses an image display device that corrects a fall in light emission luminance and prevents burn-in, a change in chromaticity, and the like.
FIG. 11A is a diagram of an image display device disclosed in JP-A-2007-156044. This image display device 1 drives an image display panel 3 with image data D1 input via a luminance correcting unit 2 and displays a desired image. In the image display panel 3, pixel circuits 5 are arranged in a matrix shape to form an image display unit 4. The pixel circuits 5 include organic EL elements 6 that form pixels and driving circuits that drive the organic EL elements 6. The image display panel 3 drives the pixel circuits 5 according to the image data D1 with a signal line driving circuit and a scanning line driving circuit not shown in the figure and displays an image formed by the image data D1 on the image display unit 4.
As shown in FIG. 11B as a sectional view taken along A-A line in FIG. 11A, the image display panel 3 shown in FIG. 11A is an image display panel of a top emission type. Therefore, in the image display panel 3, as partially enlarged and shown in FIG. 12 in comparison with FIG. 11B, TFTs 9 and the like are formed on a lower insulating substrate 8 made of glass or the like to form driving circuits of the pixel circuits 5. Thereafter, after lower electrodes 11, organic EL layers 12, and upper electrodes 13 are sequentially formed and the organic EL elements 6 are formed, the entire organic EL elements 6 are sealed by an upper transparent substrate 14. In the organic EL elements 6, the lower electrodes 11 and the upper electrodes 13 are respectively formed by reflecting electrodes and transparent electrodes. The organic EL elements 6 emit emission light L1 to the upper transparent substrate 14 side.
In the image display panel 3, a pixel circuit 5D for monitoring and a light receiving element 7 are provided in a section other than the image display unit 4. Emission light L1D of an organic EL element 6D provided in the pixel circuit 5D is received by the light receiving element 7.
The luminance correcting unit 2 measures, on the basis of light emission luminance (indicated by luminance information in FIG. 11A) of the organic EL element 6D detected by the light receiving element 7, a change in light emission efficiency of the organic EL element 6D provided in the pixel circuit 5D for monitoring. The luminance correcting unit 2 predicts a change in light emission efficiency of the organic EL element 6D from a measurement result of the light emission efficiency according to comparison of driving of the organic EL elements 6 provided in the image display unit 4 and driving of the organic EL element 6D. The luminance correcting unit 2 corrects a gradation of the image data D1 on the basis of a result of the prediction.
JP-A-2006-11388 proposes a method of correcting fluctuation in light emission luminance of an organic EL element due to a temperature change using similar dummy pixels.
USPTO Backgrounds
USPTO Backgrounds