Spectral detection device for detecting spectral components of received light

Abstract

The present invention relates to a spectral detection device ( 100 ) for detecting spectral components of received light, wherein the spectral detection device ( 100 ) comprises a filtering structure ( 110 ) arranged to filter the received light and output light with a wavelength within a predetermined wavelength range; and a light sensor ( 120 ) arranged to detect the light output by the filtering structure ( 110 ), wherein the filtering structure ( 110 ) is variable to allow a variation of the predetermined wavelength range over time. The arrangement enables a compact spectral detection device that may be provided at a low cost.

1 - 12 . (canceled) 
     
     
         13 . A spectral detection device for detecting spectral components of received light, wherein said spectral detection device comprises:
 a variable filtering structure arranged to filter the received light and to output light with a wavelength within a predetermined wavelength range, wherein the variable filtering structure includes a first switchable photonic band gap filter having a first reflecting band of frequencies arranged to receive the received light and a second switchable photonic band gap filter having a second reflecting band of frequencies different from the first reflecting band of frequencies, such that the predetermined wavelength range lies between the first and the second reflecting bands of frequencies;   wherein the predetermined wavelength range is controlled in response to receiving a control signal from a control unit connected to the variable filtering structure,   wherein said predetermined wavelength range is adjusted by applying external stimulus to said filtering structure, wherein said external stimulus is selected from the group consisting of an electric field, temperature and a mechanical force; and   a light sensor arranged to detect the light output by the second switchable photonic band gap filter of the filtering structure.   
     
     
         14 . A spectral detection device for detecting spectral components of received light, wherein said spectral detection device comprises:
 a variable filtering structure arranged to filter the received light and to output light with a wavelength within a predetermined wavelength range, wherein said predetermined wavelength range is adjusted by applying external stimulus to said filtering structure, wherein said external stimulus is selected from the group consisting of an electric field, temperature and a mechanical force;   a light sensor arranged to detect the light output by the filtering structure,   wherein the variable filtering structure comprises a single switchable photonic band gap filter that is arranged such that the output light having the predetermined wavelength range is reflected toward the light sensor, and light with a wavelength outside the predetermined wavelength is transmitted through the switchable photonic band gap filter.   
     
     
         15 . The spectral detection device of  claim 14 , wherein the predetermined wavelength range is controlled in response to receiving a control signal from a control unit connected to the variable filtering structure. 
     
     
         16 . The spectral detection device of  claim 15 , wherein the predetermined wavelength range, output by the single switchable photonic band gap filter, is adjusted by applying the external stimulus comprising the electric field. 
     
     
         17 . The spectral detection device of  claim 21 , wherein a first voltage level applied to the single switchable photonic band gap filter corresponds to a first reflecting band of frequencies and a second voltage level corresponds to a second reflecting band of frequencies within the predetermined wavelength range. 
     
     
         18 . The spectral detection device of  claim 14 , wherein the variable filtering structure comprises a pixelated filtering structure. 
     
     
         19 . The spectral detection device of  claim 18 , wherein the pixelated filtering structure comprises the first and the second switchable photonic band gap filters arranged in a first layer and a third and a fourth switchable photonic band gap filters are arranged in a second layer, wherein the first layer is disposed adjacent the second layer. 
     
     
         20 . The spectral detection device of  claim 19 , wherein the pixelated filtering structure is segmented into at least four regions, wherein light falling onto a first region passes the first switchable photonic band gap filter and the third switchable photonic band gap filter, wherein light falling onto a second region passes the second switchable photonic band gap filter and the fourth switchable photonic band gap filter, wherein light falling onto a third region passes the first switchable photonic band gap filter and the fourth switchable photonic band gap filter; and wherein light falling onto the fourth region passes the second switchable photonic band gap filter and the third switchable photonic band gap filter. 
     
     
         21 . The spectral detection device of  claim 19 , wherein the at least one light sensor comprises a light sensor corresponding to each of the pixels of the pixelated filtering structure.