Display system having circadian effect on humans

• US 8,646,939 B2
• Filed: 12/23/2009
• Issued: 02/11/2014
• Est. Priority Date: 12/23/2008
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Bues, Matthias, Stefani, Oliver, Pross, Achim
• Primary Examiner(s): Truong, Bao Q
• Application Number:
  US13/141,924
• Publication Number:
  US 20120069551A1
• Time in Patent Office: 1,511 Days
• Field of Search: 362 971- 974, 362/230, 362/231, 362/458, 362/234, 362/253, 349/61, 345 76- 83, 345/102
• US Class Current: 362/231
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133624 characterised by their spectral emissions
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light

Abstract

A display system includes an illumination unit in which a predetermined light spectrum can be produced with the illumination unit, the average light intensity of which light spectrum can be reduced or increased over the wavelength range of 420 nm to 500 nm relative to the average light intensity above and below this wavelength range such that the predetermined light spectrum is greater relative to a light spectrum produced without this reduction or increase.

Claims

1. A display system for optical display of analog or digital information, comprising:

a display unit and an illumination unit that illuminates the display unit on the basis of an additive or subtractive color synthesis with a predetermined light spectrum;

or

an illumination unit that is configured as a self-illuminating display unit which produces the display of the information on the basis of an additive or subtractive color synthesis with a predetermined light spectrum;

wherein a predetermined light spectrum can be produced with the illumination unit, the light intensity of which light spectrum is reduced or increased over the wavelength range of 420 nm to 500 nm relative to the light intensity/intensities above and/or below this wavelength range and/or the light intensity/intensities of which is/are increased above and/or below this wavelength range relative to the light intensity in this wavelength range such that the predetermined light spectrum is metameric to a light spectrum produced without this reduction and/or increase.

2. The display system of claim 1, wherein the additive or subtractive color synthesis comprises an RGB color synthesis and the predetermined light spectrum comprises a background illumination.

3. The display system of claim 1, wherein the average intensity over the wavelength range of 420 nm to 500 nm relative to the average intensity over a wavelength range of the same width which abuts at the top against this wavelength range and/or relative to the average intensity over a wavelength range of the same width which abuts at the bottom against this wavelength range is reduced or increased by at least 10%.

4. The display system of claim 1, wherein the illumination unit has a plurality of individual light sources with respectively different light spectra, the maxima of which differ by at least 10 nm and wherein the predetermined light spectrum can be produced by additive superimposition of the individual light spectra of the light sources.

5. The display system of claim 4, comprising

a first light source that has an emission maximum in the range above 380 nm and below an upper limit of 460 nm, the relative intensity component of light emitted above the upper limit in the light emitted in total being less than 20%;

and/or

a second light source that has an emission maximum in the range below 550 nm and above a lower limit of 470 nm, the relative intensity component of light emitted below the lower limit in the light emitted in total being less than 20%,

and

at least one further light source that has an emission maximum in the green range between 490 and 575 nm and/or in the red range between 650 nm and 750 nm.

6. The display system of claim 5, wherein the first and/or the second light source and also at least one of the further light sources, are configured such that the predetermined light spectrum which is produced and/or can be produced therewith by additive superimposition is metameric with a light spectrum which can be produced by at least one first light source with an emission maximum in the range of 420 nm to 500 nm, by a second light source with an emission maximum in the green range between 490 and 575 nm, and by a third light source with an emission maximum in the red range between 650 nm and 750 nm.

7. The display system of claim 5, wherein the first and/or the second light source and also at least one of the further light sources are configured such that white light can be produced therewith by additive superimposition.

8. The display system of claim 4, wherein the illumination unit with a plurality of individual light sources with respectively different light spectra for at least one of the light spectra, has a plurality of light sources per spectrum, which are disposed spatially at a spacing from each other and produce the respective light spectrum.

9. The display system of claim 4, wherein at least one of the light sources is a light diode.

10. The display system of claim 1, wherein the display unit comprises a two-dimensional array of LCD elements and the illumination unit comprises a background illumination with a plurality of light sources with respectively different light spectra.

11. The display system of claim 1, wherein the illumination unit configured as a self-illuminating display unit comprises a two-dimensional array of a large number of individual illumination sub-units, which can be actuated electrically independently of each other, in the form of organic light diodes (OLEDs), at least one of the illumination sub-unit(s) being configured such that, with it/them, a predetermined light spectrum can thus be produced.

12. The display system of claim 11, wherein the illumination sub-unit(s) comprises/comprise a plurality of individual emission layers.

13. The display system of claim 1, wherein the metamerism of the two light spectra applies directly for producible and/or produced light spectra, i.e. light spectra which are not modified by optical elements in their spectral composition.

14. The display system of claim 1, wherein the metamerism of the two light spectra applies for light spectra which are modified in their spectral composition by at least one optical element.

15. The display system of claim 1, wherein the display system comprises a screen that is selected from the group consisting of a liquid crystal screen (LCD), a color LCD which is time-sequentially controlled or configured with a color filter attachment and/or is LED-illuminated, an OLED screen, a screen of a portable computer, a screen of a mobile radio device, a screen of a PDA, a screen of a projector, and a screen of an LED-illuminated projector.

16. The display system of claim 1, further comprising a picture signal adaptation unit with which the individual additive or subtractive signal components of the color synthesis, which can be supplied and/or is supplied to the display unit, can be modified as a function of the produced predetermined light spectrum.

17. The display system of claim 1, further comprising a control unit which is configured to control the illumination unit with respect to its emitted intensity.

18. The display system of claim 1, wherein the spectral characteristics of the light source and/or the filter characteristics of optical filter elements used in or with the display unit are programmed into the control unit.

19. The display system of claim 1, wherein the control unit is configured to control the emitted intensity of the illumination unit as a function of the picture content which is to be displayed by the display unit.

20. The display system of claim 1, wherein there can be produced with the illumination unit, a plurality of predetermined light spectra which are metameric respectively to a light spectrum produced without a reduction and/or increase.

21. The display system of claim 20, wherein different predetermined light spectra which change respectively after predefined time intervals and/or by a time of day-dependent change in the degree of increase and/or reduction.

22. The display system of claim 1, wherein the illumination unit is connected rigidly or detachably to the display unit.

23. A display method for displaying analog or digital information on a display system comprising:

producing a predetermined light spectrum on the basis of an additive or subtractive color synthesis using an illumination unit to illuminate a display unit and display the analog or digital information;

or

producing a predetermined light spectrum on the basis of an additive or subtractive color synthesis using an illumination unit configured as a self-illuminating display unit to display the analog or digital information;

wherein a predetermined light spectrum is produced with the illumination unit, the light intensity of which light spectrum is reduced or increased over the wavelength range of 420 nm to 500 nm relative to the light intensity/intensities above and/or below this wavelength range and/or the light intensity/intensities of which is/are increased above and/or below this wavelength range relative to the light intensity in this wavelength range such that the predetermined light spectrum is metameric to a light spectrum produced without this reduction and/or increase.