Multiple wavelength light emitting device, electronic apparatus, and interference mirror

Abstract

A multiple wavelength light emitting device is provided wherewith the resonance strength and directivity between colors can be easily adjusted for balance. This light emitting device comprises a light emission means 4 for emitting light containing wavelength components to be output, and a semi-reflecting layer group 2 wherein semi-reflecting layers 2 R, 2 G, and 2 B that transmit some light having specific wavelengths emitted from the light emission means and reflect the remainder are stacked up in order in the direction of light advance in association with wavelengths of light to be output. Light emission regions A R , A G , and A B are determined in association with the wavelengths of light to be output. The configuration is such that, in the light emission regions, the distances L R , L G and L B between a reflecting surface for fight from the light emission means side of the semi-reflecting layers 2 R, 2 G, and 2 B that reflect light output from those light emission regions and a point existing in an interval from the end of the light emitting layer on the semi-reflecting layer group side to the reflecting layer are adjusted so as to have an optical path length at which that light resonates.

What is claimed is: 
     
       1. A multiple wavelength light emitting device for emitting light of a plurality of differing wavelengths comprising:
 light emission means for emitting light containing wavelength components to be output; 
 a reflecting layer placed in proximity to on one side of said light emission means; 
 a semi-reflecting layer group opposite said reflecting layer with said light emission means therebetween, the semi-reflecting layer group having semi-reflecting layers that reflect some light emitted from said light emission means having specific wavelengths and that transmit the remainder of the light emitted from said light emission means, stacked in order, in a direction of light advance so as to correspond with light wavelengths to be output; and 
 two or more light emission regions wherein the wavelength of the output light differs wherein:
 the distance between the reflecting layer for light from the light emission means side of the semi-reflecting layer group that partially reflects light output from that light emission region and a point at which light is emitted, existing in an interval from an end surface of said light emission means on the semi-reflecting layer group side to a surface of said reflecting layer, is adjusted so as to have an optical path length such that light of the wavelength output from that light emission region resonates and having an optical path length such that the light of the wavelength output from the light emission region resonates, 
 wherein said point in the interval from the end surface of saidthe light emission means on the semi-reflecting layer group side to the surface of said reflecting layer is a light emission point in said light emission means, wherein 
 the light emission means is separated into at least a first light emission region and a second light emission region, 
 the first light emission region has a first transparent electrode layer and a first light emitting layer, the first light emitting layer being located on the reflecting layer side of the first transparent electrode layer, 
 the second light emission region has a second transparent electrode layer and a second light emitting layer, the second light emitting layer being located on the reflecting layer side of the second transparent electrode layer, 
 the first transparent electrode layer is separated from the second transparent electrode layer, and 
 the first light emission layer is separated from the second light emission layer. 
 
 
     
     
       2. A multiple wavelength light emitting device according to  claim 1 , wherein said semi-reflecting layer group has a plurality of types of semi-reflecting layers responsive to light of a plurality differing wavelengths that are placed uniformly without any separation between light emission regions. 
     
     
       3. A multiple wavelength light emitting device according to  claim 1 , wherein said reflecting surface for light from light emission means side of semi-reflecting layer in said semi-reflecting layer group is in a different position in thickness direction for each light emission region of different light emission wavelength. 
     
     
       4. A multiple wavelength light emitting device according to  claim 1 , wherein said point existing in interval from end of said light emission means on semi-reflecting layer group side to said reflecting layer is on reflecting surface of said reflecting layer. 
     
     
       5. A multiple wavelength light emitting device according to  claim 4 , wherein, in a light emission region that outputs light of wavelength λ, distance L between a reflecting surface for light from light emission means side of said semi-reflecting layer of said plurality of semi-reflecting layers that reflects light of wavelength λ and a point existing in interval from end of said light emission means on semi-reflecting layer group side thereof to said reflecting layer is adjusted so that
   L=Σdi
 
   Σ(ni·di)+m 1 ·(Φ/2π)·=m 2 ·λ/2
 
 
       where ni is refractive index of i'th substance between said semi-reflecting layer and said light emitting surface, di is thickness thereof, Φ is phase shift occurring at said reflecting surface in said reflecting layer, and m 1  and m 2  are natural numbers. 
     
     
       6. A multiple wavelength light emitting device according to  claim 1 , wherein a point where an electric field becomes maximized between electrodes in an organic electroluminescence layer coincides with said point at which light is emitted. 
     
     
       7. A multiple wavelength light emitting device according to  claim 1 , wherein, in a light emission region that outputs light of wavelength λ, distance L between a reflecting surface for light from light emission means side of said semi-reflecting layer of said plurality of semi-reflecting layers that reflects light of wavelength λ and a light emission point existing in interval from end of said light emission means on semi-reflecting layer group side thereof to said reflecting layer is adjusted so that
   L=ρdi
 
   Σ(ni·di)=m 2 ·λ/2+(2m 3 +1)·λ/4
 
 
       where ni is refractive index of the i'th substance between said reflective surface and said light emission point, di is thickness thereof, m 2  is a natural number, and m 3  is an integer greater than 0. 
     
     
       8. A multiple wavelength light emitting device according to  claim 1 , wherein, in said semi-reflecting layer group, said semi-reflecting layer that reflects light of longer wavelength is positioned on side nearer to said light emitting device. 
     
     
       9. A multiple wavelength light emitting device according to  claim 1 , wherein semi-reflecting layers configuring said semi-reflecting layer group are configured with two layers of different refractive index stacked alternately. 
     
     
       10. A multiple wavelength light emitting device according to  claim 9 , wherein said semi-reflecting layers are adjusted so as to satisfy the relationship
   n 1 ·d 1 =n 2 ·d 2 =(¼+m/2)·λ
 
 
       where n 1  is refractive index of one of said two layers having different refractive indexes, d 1  is thickness thereof, n 2  is refractive index of other layer, d 2  is thickness thereof, λ is wavelength of light reflected in that semi-reflecting layer, and m is 0 or a natural number. 
     
     
       11. A multiple wavelength light emitting device according to  claim 1 , wherein said semi-reflecting layer group comprises gap adjustment layers, between semi-reflecting layers thereof, for adjusting distance between reflecting surface for light from said light emission means side of semi-reflecting layer other than that semi-reflecting layer closest to said light emission means and a point existing interval from end of said light emission means on semi-reflecting layer group side to said reflecting layer. 
     
     
       12. A multiple wavelength light emitting device according to  claim 9 , wherein, in order to adjust distance between reflecting surface for light from said light emission means said of semi-reflecting layer other than that semi-reflecting layer closest to said light emission means and a point existing in interval from end of said light emission means on semi-reflecting layer group side to said reflecting layer, thickness of one layer in laminar structure wherein said layers of different refractive index configure said semi-reflecting layers is altered. 
     
     
       13. A multiple wavelength light emitting device according to  claim 1 , wherein multiple types of light emission means for emitting a relatively large amount of light having light components of wavelengths corresponding to said light emission regions are provided so that they are associated with said light emission regions. 
     
     
       14. A multiple wavelength light emitting device according to  claim 1 , wherein light emission means capable of emitting light having wavelength components associated with all said light emission regions are provided commonly for all said light emission regions. 
     
     
       15. A multiple wavelength light emitting device according to  claim 1 , wherein said light emission means are an organic electro-luminescence layer sandwiched between electrode layers, and electrode provided on back side thereof corresponds to said reflecting layer. 
     
     
       16. A multiple wavelength light emitting device according to  claim 15 , wherein said light emission means comprise a hole transport layer on positive electrode side of said organic electro-luminescence layer. 
     
     
       17. A multiple wavelength light emitting device according to  claim 15 , wherein said light emission means comprises an electron transport layer on negative electrode side of said organic electro-luminescence layer. 
     
     
       18. A multiple wavelength light emitting device according to  claim 15 , wherein distance between reflecting surface for light from light emission means side of said semi-reflecting layers and a point existing in interval from end of said light emission means on semi-reflecting layer side thereof to said reflecting layer is adjusted with thickness of positive electrode positioned on semi-reflecting layer group side of said light emission means. 
     
     
       19. A multiple wavelength light emitting device according to  claim 15 , comprising a layer on semi-reflecting layer group side of said light emission means for purpose of adjusting distance between reflecting surface for light from light emission means side of said semi-reflecting layers and a point existing in interval from end of said light emission means on semi-reflecting layer side thereof to said reflecting layer. 
     
     
       20. A multiple wavelength light emitting device according to  claim 15 , wherein said negative electrode is made of a material exhibiting light reflectance. 
     
     
       21. A multiple wavelength light emitting device according to  claim 15 , wherein at least one of electrode films sandwiched around said organic electro-luminescence layer is formed separately and is independently, associated with said light emission regions. 
     
     
       22. A multiple wavelength light emitting device according to  claim 21 , wherein one or other of said electrode films is separated by a partition member that partitions said light emission regions from one another. 
     
     
       23. A multiple wavelength light emitting device according to  claim 21 , wherein, of said electrode films, the negative electrode is separated in association with said light emission regions, and thickness of said positive electrode is altered in association with said light emission regions in order to adjust distance between reflecting surface for light from light emission means side of said semi-reflecting layers and a point existing in interval from end of said light emission means on semi-reflecting layer side thereof to said reflecting layer. 
     
     
       24. A multiple wavelength light emitting device according to  claim 21 , wherein, of said electrode films, the positive electrode is separated in association with said light emission regions, and thickness thereof is altered in association with said light emission regions in order to adjust distance between reflecting surface for light from light emission means side of said semi-reflecting layers and a point existing in interval from end of said light emission means on semi-reflecting layer side thereof to said reflecting layer. 
     
     
       25. A multiple wavelength light emitting device according to  claim 21 , comprising drive circuits for individually driving said electrically separated electrode films. 
     
     
       26. An electronic apparatus comprising:
 the multiple wavelength light emitting device claimed in  claim 25 . 
 
     
     
       27. A electronic apparatus according to  claim 26 , wherein said light emission regions in said multiple wavelength light emitting device are formed as pixels for displaying images, and function as display elements configured so that the driving of pixels can be controlled in response to image information. 
     
     
       28. An interference mirror comprising:
 a plurality of interference reflecting layers, configured so that some light of mutually different wavelength can be reflected, positioned sequentially in the direction of the optical axis; and   a plurality of gap adjacent layers, each of which has a different thickness with respect to one another, in the direction of the optical axis, positioned between said interference reflecting layers.