Display apparatus, mobile terminal and luminance control method in the mobile terminal

• US 20050093958A1
• Filed: 09/27/2004
• Published: 05/05/2005
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Murata, Haruhiko, Yabukawa, Takashi, Goya, Hiroyuki, Mori, Yukio, Tanase, Susumu, Inoue, Masutaka, Kinoshita, Shigeo, Yamashita, Atsuhiro
• Granted Patent: US 7,456,852 B2
• Time in Patent Office: Days
• US Class Current: 347/207
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes

Abstract

When an input detection unit has detected that no user operation has been performed to an organic EL display apparatus for a predetermined period of time or when a processing detection unit has detected that a predetermined processing is being performed, the input detection unit or the processing detection unit outputs an instruction to a reference voltage adjusting unit to modify a reference voltage referenced by a DAC unit upon conversion to an analog output signal.

Claims

1. A display apparatus comprising:

an optical element; and

a luminance changing unit which lowers a luminance to be set to the optical element when there is no input from a user over a predetermined period.

3. The display apparatus according to claim 1, wherein the luminance changing unit lowers a maximum luminance to be allowed to set to the optical element.

4. The display apparatus according to claim 1, wherein the luminance changing unit adjusts a gain of a luminance so that a brightness of whole of a display image becomes dark.

5. The display apparatus according to claim 1, wherein the luminance changing unit performs gamma correction so that a brightness of whole of a display image becomes dark.

6. The display apparatus according to claim 1, wherein the luminance changing unit adjusts a luminance so that text data included in a display image can be highlighted.

7. The display apparatus according to claim 1, wherein the luminance changing unit reduces the number of gradations of a display image to generate a summary image, and lowers a maximum luminance to be set to the optical element in accordance with new number of gradations of the summary image.

8. The display apparatus according to claim 1, wherein the luminance changing unit controls power of a power supply which supplies electric power to the optical element.

9. The display apparatus according to claim 1, wherein the luminance changing unit adjusts ratio of a emitting period and a non-emitting period of the optical element.

2. A display apparatus comprising:

an optical element; and

a luminance changing unit which lowers a luminance to be set to the optical element during advance of a predetermined processing.

10. A mobile terminal comprising:

an organic EL display;

a distinction means which distinguishes a type of a content displayed on said organic EL display;

a control means which controls display luminance of an image to be displayed on said organic EL display in accordance with the type of the content distinguished by said distinction means.

11. The mobile terminal according to claim 10, wherein said control means including:

a DA converter which converts a digital image signal corresponding to the content to be displayed on said organic EL display to an analog image signal, based on an input/output characteristic defined by a given reference voltage, and supplies the analog image signal to said organic EL display; and

a reference voltage adjusting circuit which controls the reference voltage to be supplied to said DA converter based on the type of the content distinguished by said distinction means.

12. The mobile terminal according to claim 11, wherein there are a black-side reference voltage for defining an emitting luminance corresponding to a black level of an input signal and a white-side reference voltage for defining an emitting luminance corresponding to a white level of the input signal as reference voltages supplied to said DA converter, and said reference voltage adjusting circuit controls the white-side reference voltage based on the kind of the content distinguished by the distinction means.

13. A luminance control method in a mobile terminal comprising an organic EL display, the method including:

a first step of distinguishing a type of a content to be displayed on the organic EL display; and

a second step of controlling a display luminance of an image to be displayed on the organic EL display in accordance with the type of the content distinguished by the first step.

14. The luminance control method in the mobile terminal according to claim 13, wherein the mobile terminal comprises a DA converter which converts a digital image signal corresponding to the content to be displayed on the organic EL display to an analog image signal, based on an input/output characteristic defined by a given reference voltage, and supplies the analog image signal to the organic EL display;

and

said second step controls an amplitude of an image input signal by controlling a reference voltage supplied to the DA converter based on the type of the content distinguished by said first step.

15. The luminance control method in the mobile terminal according to claim 14, wherein there are a black-side reference voltage for defining an emitting luminance corresponding to a black level of an input signal and a white-side reference voltage for defining an emitting luminance corresponding to a white level of the input signal as reference voltages supplied to the DA converter, and

said second step controls the white-side reference voltage based on the kind of the content distinguished by said first step.