Patent Publication Number: US-2022231201-A1

Title: Devices including green-emitting phosphors

Description:
BACKGROUND 
     Current display device technology relies on liquid crystal displays (LCDs), which is one of the most widely used flat panel displays for industrial and residential applications. However, next-generation devices that will have low energy consumption, compact size, and high brightness, requiring improved color gamut (NTSC ratio). 
     LED backlight units (BLU) for use in displays are based on a combination of a blue LED, a green phosphor and a red phosphor. The color gamut of LED BLUs is largely determined by the choice of phosphors. Red phosphor K 2 SiF 6 :Mn 4+  has a peak with full width at half maximum (FWHM) of 6 to 8 nm yields high color reproducibility in correspondence with the relative intensity of the emission peak. Green phosphor, β-SiAlON:Eu 2+  has a half width of 46 to 52 nm and has peak wavelength of 534 nm, which is not a pure green but greenish yellow in color. Accordingly, there is also a need for new green emitting phosphors that efficiently absorb blue radiation, provide high quantum efficiency, and have improved color rendering. 
     BRIEF DESCRIPTION 
     Briefly, in one aspect, the present disclosure relates to a device including an LED light source optically coupled to a phosphor material including a green-emitting phosphor selected from the group consisting of compositions (A1)-(A62) and combinations thereof. 
     Another aspect is a lighting apparatus including the device. Yet another aspect is a backlight apparatus including the device. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic of a device, in accordance with one embodiment of the disclosure; 
         FIG. 2  is a schematic cross-sectional view of a lighting apparatus, in accordance with one embodiment of the disclosure; 
         FIG. 3  is a schematic cross-sectional view of a lighting apparatus, in accordance with another embodiment of the disclosure; 
         FIG. 4  is a schematic cross-sectional view of a lighting apparatus, in accordance with yet another embodiment of the disclosure; and 
         FIG. 5  is a schematic perspective view of a backlight apparatus, in accordance with one embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following specification and the claims, the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. As used herein, the term “or” is not meant to be exclusive and refers to at least one of the referenced components being present and includes instances in which a combination of the referenced components may be present, unless the context clearly dictates otherwise. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially” is not limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. 
     Devices according to the present disclosure include an LED light source optically coupled to a phosphor material including a green-emitting phosphor selected from the group consisting of compositions (A1)-(A62) and combinations thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions (A2), (A18), (A26), (A27), (A59) and combinations thereof. 
     The compositions of the groups (A1)-(A12), (A55), (A60) and (A61) represent formulae, and each formula represents various possible green-emitting phosphors. A formula may include a green-emitting phosphor of respective formula or a combination of possible green-emitting phosphors. Furthermore, some compositions such as (A40)-(A62) show “U” after the colon “:” in the composition. This representation indicates that the composition is doped with U (uranium) and may be referred to as U-doped phosphor. 
     In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A1). Examples of the green-emitting phosphor of formula (A1) include CsUSiO 6 , RbUSiO 6 , or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A2). Examples of the green-emitting phosphor of formula (A2) Include Cs 2 (UO 2 )Si 2 O 6 , Rb 2 (UO 2 )Si 2 O 6  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A3). Examples of the green-emitting phosphor of formula (A3) include K 2 MnU 3 O 11 , Rb 2 MnU 3 O 11  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A3). Examples of the green-emitting phosphor of formula (A4) include K 4 CaU 3 O 12 , K 4 SrU 3 O 12  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A5). Examples of the green-emitting phosphor of formula (A5) include Ca 3 UO 6 , Sr 3 UO 6  or a combination thereof. 
     In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A6). Examples of the green-emitting phosphor of formula (A6) include Na 3 Ca 1.5 UO 6 , Na 4.5 Nd 0.5 UO 6  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A7). Examples of the green-emitting phosphor of formula (A7) include CaUO 4 , MnUO 4 , FeUO 4  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A8). Examples of the green-emitting phosphor of formula (A8) include Na 3 GaU 6 F 30 , Na 3 AlU 6 F 30 , Na 3 TiU 6 F 30 , Na 3 VU 6 F 30 , Na 3 CrU 6 F 30 , and Na 3 FeU 6 F 30 . In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A9). Examples of the green-emitting phosphor of formula (A9) include Ba 2 NiUO 6 , Ba 2 CuUO 6  and Ba 2 ZnUO 6 . In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A10). Examples of the green-emitting phosphor of formula (A10) include Na 3 K 3 (UO 2 ) 3 (Si 2 O 7 )-2H 2 O, Na 3 Rb 3 (UO 2 ) 3 (Si 2 O 7 )-2H 2 O or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A11). Examples of the green-emitting phosphor of formula (A11) include Rb 3 (U 2 O 4 )Ge 2 O 7 , Cs 3 (U 2 O 4 )Ge 2 O 7  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A12). Examples of the green-emitting phosphor of formula (A12) include Ba 2 (UO 2 )(PO 4 ) 2 , Ba 2 (UO 2 )(AsO 4 ) 2  or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A27). Examples of the green-emitting phosphor of formula (A27) include A(UO 2 )OCl. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A55). Examples of the green-emitting phosphor of formula (A55) include CaWO 4 :U, CdWO 4 :U, MgWO 4 :U or a combination thereof. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A60). Examples of the green-emitting phosphor of formula (A60) include Y 2 TeO 6 :U and Gd 2 TeO 6 :U. In some embodiments, the green-emitting phosphor is selected from the group consisting of compositions of formula (A61). Examples of the green-emitting phosphor of formula (A61) comprises Ca 3 TeO 6 :U, Sr 3 TeO 6 :U, Mg 3 TeO 6 :U or a combination thereof. Other suitable examples of the green-emitting phosphor include K 6 (K 5 F)U 6 Si 8 O 40 , SrZnP 2 O 7 :U, KUO 3 Cl, CsUO 3 Cl, NaUO 3 Cl, RbUO 3 Cl or combinations thereof. 
     The green-emitting phosphors disclosed herein may absorb radiation in the near-UV or blue region (a wavelength range between about 400 nm and 470 nm) and emit in a narrow region with an emission peak centered in a wavelength range from about 510 nm to about 540 nm, particularly from about 520 nm to about 530 nm. In some embodiments, these phosphors may be utilized in a phosphor blend to produce white light. These narrow green-emitting phosphors may be useful in display applications, in particular. 
     In some embodiments, an activator ion may be further present in the green emitting phosphor such as Mn 2+ , Mn 4+ , Ce 3+ , Sn 2+ , Bi 3+ , Sb 3+ , Cr 3+ , Tb 3+ , Pr 3+ , Eu 3+ , Ti 4+ , In + , TI + , Dy 3+  and Pb 2+ . In embodiments where the green emitting phosphor includes U-doped phosphor (for example, compositions (A40)-(A62)), the activator ion may be present as an additional activator ion. 
     Devices of the present disclosure may be used as lighting and backlight apparatuses for general illumination and display applications. Examples include chromatic lamps, plasma screens, xenon excitation lamps, UV excitation marking systems, automotive headlamps, home and theatre projectors, laser pumped devices, point sensors, liquid crystal display (LCD) backlight units, televisions, computer monitors, mobile phones, smartphone, tablet computers and other handheld devices that have a display including an LED source as described herein. The list of these applications is meant to be merely exemplary and not exhaustive. 
       FIG. 1  show a device  10 , according to one embodiment of the present disclosure. The device  10  includes a LED light source  12  and a phosphor material  14  including a green-emitting phosphor as described above in the present disclosure. The LED light source  12  may comprise a UV or blue emitting LED. In some embodiments, the LED light source  12  produces blue light in a wavelength range from about 440 nm to about 460 nm. In the device  10 , the phosphor material  14  including the green-emitting phosphor as described herein, is optically coupled to the LED light source  12 . Optically coupled means that radiation from the LED light source  12  is able to excite the phosphor material  14 , and the phosphor material  14  is able to emit light in response to the excitation by the radiation. The phosphor material  14  may be disposed on a part of the LED light source  12  or located remotely at a distance from the LED light source  12 . 
     The LED light source may be an inorganic LED light source or an organic LED light source. The term ‘LED light source’, as used herein, is meant to encompass all LED light sources such as semiconductor laser diodes (LD), inorganic light emitting diodes, organic light emitting diodes (OLED) or a hybrid of LED and LD. Further, it should be understood that the LED light source may be replaced, supplemented or augmented by another radiation source unless otherwise noted and that any reference to semiconductor, semiconductor LED, or LED chip is merely representative of any appropriate radiation source, including, but not limited to, LDs and OLEDs. 
     In some embodiments, the phosphor material  14  additionally includes a red emitting phosphor of formula I: A 2 [MF 6 ]:Mn 4+ , where A is Li, Na, K, Rb, Cs, or a combination thereof; and M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof. The red emitting phosphor of formula I is optically coupled to the LED light source  12 . The phosphors of formula I are described in U.S. Pat. Nos. 7,497,973, and 8,906,724, and related patents assigned to the General Electric Company. 
     Examples of the red emitting phosphors of formula I include K 2 [SiF 6 ]:Mn 4+ , K 2 [TiFe]:Mn 4+ , K 2 [SnF 6 ]:Mn 4+ , Cs 2 [TiF 6 ]:Mn 4+ , Rb 2 [TiF 6 ]:Mn 4+ , Cs 2 [SiF 6 ]:Mn 4+ , Rb 2 [SiF 6 ]:Mn 4+ , Na 2 [TiF 6 ]:Mn 4+ , Na 2 [ZrF 6 ]:Mn 4+ , K 3 [ZrF 7 ]:Mn 4+ , K 3 [BiF 7 ]:Mn 4+ , K 3 [YF 7 ]:Mn 4+ , K 3 [LaF 7 ]:Mn 4+ , K 3 [GdF 7 ]:Mn 4+ , K 3 [NbF 7 ]:Mn 4+  or K 3 [TaF 7 ]:Mn 4+ . In certain embodiments, the phosphor of formula I is K 2 SiF 6 :Mn 4+ . 
     The phosphor material  14  may be present in any form such as powder, glass, composite e.g., phosphor-polymer composite or phosphor-glass composite. Further, the phosphor material  14  may be used as a layer, sheet, strip, dispersed particulates, or a combination thereof. In some embodiments, the phosphor material  14  includes the green-emitting phosphor in glass form. In some of these embodiments, the device  10  may include the phosphor material  14  in form of a phosphor wheel (not shown in figures). The phosphor wheel may include the green-emitting phosphor in glass form. A phosphor wheel and related devices are described in a previously filed patent application Serial No. PCT/US17/31654. 
     In some embodiments, the device  10  may be a backlight unit for display applications. In these embodiments, the phosphor material  14  including the green-emitting phosphor, may be present in form of a sheet or strip that is mounted or disposed on a surface of the LED light source  12 . A backlight unit and related devices are described in a previously filed patent application Ser. No. 15/370,762. 
       FIG. 2  illustrates a lighting apparatus or lamp  100 , in accordance with some embodiments. The lighting apparatus  100  includes an LED chip  22 , and leads  24  electrically attached to the LED chip  22 . The leads  24  may comprise thin wires supported by a thicker lead frame(s)  26  or the leads  24  may comprise self supported electrodes and the lead frame may be omitted. The leads  24  provide current to LED chip  22  and thus cause it to emit radiation. 
     The LED chip  22  may be encapsulated within an envelope  28 . The envelope  28  may be formed of, for example glass or plastic. The LED chip  22  may be enclosed by an encapsulant material  32 . The encapsulant material  32  may be a low temperature glass, or a polymer or resin known in the art, for example, an epoxy, silicone, epoxy-silicone, acrylate or a combination thereof. In an alternative embodiment, the lighting apparatus  100  may only include the encapsulant material  32  without the envelope  28 . Both the envelope  28  and the encapsulant material  32  should be transparent to allow light to be transmitted through those elements. 
     With continued reference to  FIG. 2 , a layer  30  of the phosphor material including the green-emitting phosphor as described herein is disposed on a surface  21  of the LED chip  22 . The layer  30  may be disposed by any appropriate method, for example using a slurry prepared by mixing silicone and the phosphor material. In one such method, a silicone slurry in which the particles of the phosphor material are randomly suspended, is placed around the LED chip  22 . This method is merely exemplary of possible positions of the layer  30  and LED chip  22 . As illustrated, the layer  30  may be disposed for example, coated over or directly on the surface  21  of the LED chip  22  by coating and drying the slurry over the LED chip  22 . The surface  21  is a light emitting surface of the LED chip  22 . The light emitted by the LED chip  22  mixes with the light emitted by the phosphor material of the layer  30  to produce desired emission. 
     In some other embodiments, the phosphor material including green-emitting phosphor as described herein is interspersed within the encapsulant material  32 , instead of being disposed directly on the LED chip  22  as shown in  FIG. 2 .  FIG. 3  illustrates a lighting apparatus  300  that includes particulates  34  of the phosphor material interspersed within a portion of the encapsulant material  32 . The particulates of the phosphor material may be interspersed throughout the entire volume of the encapsulant material  32 . Blue light emitted by the LED chip  22  mixes with the light emitted by the particulates  34  of the phosphor material, and the mixed light transmits out from the lighting apparatus  200 . 
     In some other embodiments, a layer  36  of the phosphor material including the green-emitting phosphor, is coated onto a surface of the envelope  28  as illustrated in  FIG. 4 , instead of being formed over the LED chip  22  ( FIG. 2 ). As shown, the layer  36  is coated on an inside surface  29  of the envelope  28 , although the layer  36  may be coated on an outside surface of the envelope  28 , if desired. The layer  36  may be coated on the entire surface of the envelope  28  or only a top portion of the inside surface  29  of the envelope  28 . The UV/blue light emitted by the LED chip  22  mixes with the light emitted by the layer  36 , and the mixed light transmits out. Of course, the phosphor material may be located in any two or all three locations (as shown in  FIGS. 2-4 ) or in any other suitable location, such as separately from the envelope  28  or integrated into the LED chip  22 . 
     In any or all the above configurations, the lighting apparatus  100 ,  200 , or  300  shown respectively in  FIG. 2 ,  FIG. 3  or  FIG. 4  may also include a plurality of scattering particles (not shown), which are embedded in the encapsulant material  32 . The scattering particles may comprise, for example, alumina, silica, zirconia, or titania. The scattering particles effectively scatter the directional light emitted from the LED chip  22 , preferably with a negligible amount of absorption. 
     Some embodiments are directed to a backlight apparatus  50  as illustrated in  FIG. 5 . The backlight apparatus  50  includes a surface mounted device (SMD) type light emitting diode for backlight or display applications. This SMD is a “side-emitting type” and has a light-emitting window  52  on a protruding portion of a light guiding member  54 . An SMD package may comprise an LED chip as defined above, and a phosphor material including the green-emitting phosphor as described herein. In some embodiments, the SMD package may comprise an LED chip as defined above, and a phosphor material including the green-emitting phosphor and a red-emitting Mn 4+  doped phosphor of formula I as described herein. 
     In addition to the green-emitting phosphor and, optionally, the red-emitting Mn 4+  doped phosphor of formula I, the phosphor material may further include one or more other luminescent materials. Additional luminescent materials such as blue, yellow, red, orange, or other color phosphors may be used in the phosphor material to customize the white color of the resulting light and produce specific spectral power distributions. 
     Suitable additional phosphors for use in the phosphor material include, but are not limited to: 
     ((Sri 1−z (Ca,Ba,Mg,Zn) z ) 1−(x+w) (Li,Na,K,Rb) w Ce x ) 3 (Al 1−y Si y )O 4+y+3(x−w) F 1−y−3(x−w) , 0&lt;x≤0.10, 0≤y≤0.5; 0≤z≤0.5, 0≤w≤x; (Ca,Ce) 3 Sc 2 Si 3 O 12  (CaSiG); (Sr,Ca,Ba) 3 Al 1−x Si x O 4+x F 1−x :Ce 3+  (SASOF)); (Ba,Sr,Ca) 5 (PO 4 ) 3 (Cl,F,Br,OH):Eu 2+ ,Mn 2+ ; (Ba,Sr,Ca)BPO 5 :Eu 2+ ,Mn 2+ ; (Sr,Ca) 10 (PO 4 ) 6 *vB 2 O 3 :Eu 2+  (wherein 0&lt;v≤1); Sr 2 Si 3 O 8 *2SrCl 2 :EU 2− ; (Ca,Sr,Ba) 3 MgSi 2 O 8 :EU 2+ ,Mn 2+ ; BaAl 8 O 13 :EU 2+ ; 2SrO*0.84P 2 O 5 *0.16B 2 O 3 :Eu 2+ ; (Ba,Sr,Ca)MgAl 10 O 17 :Eu 2+ ,Mn 2+ ; (Ba,Sr,Ca)Al 2 O 4 :Eu 2+ ; (Y,Gd,Lu,Sc,La)BO 3 :Ce 3+ ,Tb 3+ ; ZnS:Cu + ,Cl − ; ZnS:Cu + ,Al 3+ ; ZnS:Ag + ,Cl − ; ZnS:Ag + ,Al 3+ ; (Ba,Sr,Ca) 2 Si 1−n O 4−2n :Eu 2+  (wherein 0≤n≤0.2); (Ba,Sr,Ca) 2 (Mg,Zn)Si 2 O 7 :Eu 2+ ; (Sr,Ca,Ba)(Al,Ga,In) 2 S 4 :Eu 2+ ; (Y,Gd,Tb,La,Sm,Pr,Lu) 3 (Al,Ga) 5−a O 12−3/2a :Ce 3+  (wherein 0≤a≤0.5); (Ca,Sr) 8 (Mg,Zn)(SiO 4 ) 4 Cl 2 :Eu 2+ ,Mn 2+ ; Na 2 Gd 2 B 2 O 7 :Ce 3+ ,Tb 3+ ; (Sr,Ca,Ba,Mg,Zn) 2 P 2 O 7 :Eu 2+ ,Mn 2+ ; (Gd,Y,Lu,La) 2 O 3 :Eu 3+ ,Bi 3+ ; (Gd,Y,Lu,La) 2 O 2 S:Eu 3+ ,Bi 3+ ; (Gd,Y,Lu,La)VO 4 :Eu 3+ ,Bi 3+ ; (Ca,Sr)S:Eu 2+ ,Ce 3+ ; SrY 2 S 4 :Eu 2+ ; CaLa 2 S 4 :Ce 3+ ; (Ba,Sr,Ca)MgP 2 O 7 :Eu 2+ ,Mn 2+ ; (Y,Lu) 2 WO 6 :EU 3+ ,MO 6+ ; (Ba,Sr,Ca) b Si g N m :Eu 2+  (wherein 2b+4g=3m); Ca 3 (SiO 4 )Cl 2 :Eu 2+ ; (Lu,Sc,Y,Tb) 2−u−v Ce v Ca 1+u Li w Mg 2−w P w (Si,Ge) 3−w O 12−u/2  (where −0.5≤u≤1, 0&lt;v≤0.1, and 0≤w≤0.2); (Y,Lu,Gd) 2−m (Y,Lu,Gd)Ca m Si 4 N 6+m C 1−m :Ce 3+ ; (wherein 0≤m≤0.5); (Lu,Ca,Li,Mg,Y), alpha-SiAlON doped with Eu 2+  and/or Ce 3+ ; Sr(LiAl 3 N 4 ):Eu 2+ , (Ca,Sr,Ba)SiO 2 N 2 :Eu 2+ ,Ce 3+ ; beta-SiAlON:Eu 2+ ,3.5MgO*0.5MgF 2* GeO 2 :Mn 4+ ; Ca 1−c−f Ce c Eu f Al 1+c Si 1−c N 3 , (where 0≤c≤0.2, 0≤f≤0.2); Ca 1−h−r Ce h Eu r Al 1−h (Mg,Zn) h SiN 3 , (where 0≤h≤0.2, 0≤r≤0.2); Ca 1−2s−t Ce s (Li,Na) s Eu t AlSiN 3 , (where 0≤s≤0.2, 0≤t≤2, s+t&gt;0); (Sr,Ca)AlSiN 3 :Eu 2+ ,Ce 3+ , and Li 2 CaSiO 4 :Eu 2+ . 
     The ratio of each of the individual phosphors in the phosphor material may vary depending on the characteristics of the desired light output. The relative proportions of the individual phosphors in the various phosphor materials may be adjusted such that when their emissions are blended and employed in a device, for example a lighting apparatus, there is produced visible light of predetermined x and y values on the CIE chromaticity diagram. 
     Other additional luminescent materials suitable for use in the phosphor material may include electroluminescent polymers such as polyfluorenes, preferably poly(9,9-dioctyl fluorene) and copolymers thereof, such as poly(9,9′-dioctylfluorene-co-bis-N, N′-(4-butyl phenyl)di phenylamine) (F8-TFB); poly(vinylcarbazole) and polyphenylenevinylene and their derivatives. In addition, the light emitting layer may include a blue, yellow, orange, green or red phosphorescent dye or metal complex, a quantum dot material, or a combination thereof. Materials suitable for use as the phosphorescent dye include, but are not limited to, tris(1-phenylisoquinoline) iridium (III) (red dye), tris(2-phenylpyridine) iridium (green dye) and Iridium (III) bis(2-(4,6-difluorephenyl)pyridinato-N,C2) (blue dye). Commercially available fluorescent and phosphorescent metal complexes from ADS (American Dyes Source, Inc.) may also be used. ADS green dyes include ADS060GE, ADS061GE, ADS063GE, and ADS066GE, ADS078GE, and ADS090GE. ADS blue dyes include ADS064BE, ADS065BE, and ADS070BE. ADS red dyes include ADS067RE, ADS068RE, ADS069RE, ADS075RE, ADS076RE, ADS067RE, and ADS077RE. Exemplary quantum dot materials are based on CdSe, ZnS or InP, including, but not limited to, core/shell luminescent nanocrystals such as CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS or CdTe/ZnS. Other examples of the quantum dot materials include perovskite quantum dots such as CsPbX 3 , where X is Cl, Br, I or a combination thereof. 
     By use of the embodiments described in the present disclosure, particularly the phosphor materials described herein, devices can be provided producing white light for display applications for example LCD backlight units, having high color gamut and high luminosity. Alternately, by use of the embodiments described in the present disclosure, particularly the phosphor materials described herein, devices can be provided producing white light for general illumination having high luminosity and high CRI values for a wide range of color temperatures of interest (2500 K to 10000 K). 
     While only certain features of the disclosure have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.