DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Allowable Subject Matter
Claims 10 and 11 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 10, 14-15, and 17 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instances:
Claim 10 recites the broad recitation “the transmission in the visible spectrum of the guest material has a maximum value at a wavelength of at least 475nm” and the claim also recites “preferably at least 500 nm”, which is the narrower statement of the range/limitation.
Claim 14 recites the broad recitation “wherein the volume of the guest material is less than 3%... of the volume of the host material”, and the claim also recites “preferably less than 2% and most preferably less than 1% of the volume of the host material” which is the narrower statement of the range/limitation.
Claim 15 recites the broad recitation “the weight of the guest material is less than 3%... of the weight of the host material”, and the claim also recites “preferably less than 2% and most preferably less than 1% of the weight of the host material” which is the narrower statement of the range/limitation.
Claim 17 recites the broad recitation “the on-axis extinction coefficient of the guest-host liquid crystal retarder in at least one mode of operation is at least 60%”, and the claim also recites “preferably at least 80% and most preferably at least 90%” which is the narrower statement of the range/limitation.
The claim(s) are considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-9 and 12-21 are rejected under 35 U.S.C. 103 as being unpatentable over Robinson et al. (US Pub. 20190250458, Robinson) in view of Harrold et al. (US Pub. 20200026114, Harrold).
As per claim 1, Robinson teaches (in figures 1A, 1B, 2A-5C, 9A-9E) a display device comprising: a spatial light modulator (SLM 48) comprising a layer of addressable pixels (red, green and blue pixels 220, 222, 224); a display polariser (output polariser 218) arranged on an output side of the spatial light modulator (SLM 48), the display polariser being a linear polariser (paragraph 254); a reflective polariser (reflective polariser 302) arranged on an output side of the display polariser (output polariser 218), the reflective polariser being a linear polariser (paragraph 254), wherein the reflective polariser and the display polariser have electric vector transmission directions (electric vector transmission direction 303 of the reflective polariser 302 and the electric vector transmission direction 219 of the output polariser 218) that are parallel (paragraph 264); an additional polariser (additional polariser 318) arranged on the output side of the reflective polariser (reflective polariser 302), the additional polariser being a linear polariser (paragraph 254); and a liquid crystal retarder (switchable liquid crystal retarder 301) arranged between the additional polariser (additional polariser 318) and the reflective polariser (reflective polariser 302), the liquid crystal retarder (switchable liquid crystal retarder 301) comprising a liquid crystal layer (layer 314 of liquid crystal material) comprising a host material (liquid crystal material 414), wherein the host material (liquid crystal material 414) is a liquid crystal material, the liquid crystal retarder being arranged on the same side of the spatial light modulator (SLM 48) as the display polariser (output polariser 218) with the display polariser (output polariser 218) arranged between the liquid crystal retarder (switchable liquid crystal retarder 301) and the spatial light modulator (SLM 48), wherein the optical axis of the liquid crystal retarder has an alignment component perpendicular to the plane of the guest-host liquid crystal retarder in at least a state of the host material (in public mode, see figure 9A and paragraphs 324-326).
Robinson does not teach that the liquid crystal retarder is a guest-host liquid crystal retarder comprising a guest material, wherein the guest material is an anisotropic material.
However, Harrold teaches (in figure 1A-1B, 4G, and 5A), providing a guest material (guest material 414B) comprising an anisotropic material (paragraph 212) in a liquid crystal retarder (switchable guest-host liquid crystal retarder 301) wherein the optical axis of the guest-host liquid crystal retarder has an alignment component perpendicular to the plane of the guest-host liquid crystal retarder in at least a state of the host material (in wide angle viewing mode, see figure 4G and paragraphs 242-249) in order to further reduce off-axis luminance (paragraph 246).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the liquid crystal retarder in Robinson to include the guest material of Harrold.
The motivation would have been to further reduce off-axis luminance.
As per claim 2, Robinson in view of Harrold teaches that the anisotropic material (guest material 414B from Harrold) is an anisotropic optical absorber (paragraph 212 in Harrold).
As per claim 3, Robinson in view of Harrold teaches that the anisotropic material (guest material 414B from Harrold) is a dichroic dye or a pleochroic dye (paragraph 212 in Harrold).
As per claim 4, Robinson in view of Harrold teaches that the guest-host liquid crystal retarder (switchable liquid crystal retarder 301 in Robinson as modified by Harrold) is a switchable liquid crystal retarder further comprising transparent electrodes (transparent electrodes 413 and 415 in Robinson) arranged to apply a voltage capable of switching the host material between different states (see paragraphs 279-280 in Robinson).
As per claim 5, Robinson in view of Harrold teaches a control system (control system 352 in Robinson) arranged to control the voltage applied across the electrodes of the at least one switchable liquid crystal retarder (paragraph 265 in Robinson).
As per claim 6, Robinson in view of Harrold does not specifically teach that in each direction inclined to a normal to the display device, the difference between the maximum reflectance of the display device and the minimum reflectance of the display device across all switchable states of the host material is at most 15%.
However, Robinson teaches (in figure 5C) teach that in each direction inclined to a normal to the display device, the difference between the maximum reflectance of the display device and the minimum reflectance of the display device across all switchable states of the host material is at most approximately 20% (paragraph 300) which will be reduced depending on the amount of light absorbing anisotropic material included in the guest-host liquid crystal retarder under the modification from Harrold.
It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. (See MPEP § 2144.05 (II) (A) and (B)). The difference between the maximum reflectance of the display device and the minimum reflectance of the display device is a result effective variable in that it is directly dependent on the amount of dichroic dye provided in the guest-host liquid crystal retarder and Harrold teaches (in figure 3C) that as the amount of dichroic dye increases display luminance is decreased in the front view resulting in a dimmer display and decreased to a larger degree in the side resulting in increased security.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to set the amount of anisotropic material such that difference between the maximum reflectance of the display device and the minimum reflectance of the display device across all switchable states of the host material is at most 15% in order to balance the need for a bright display and security.
As per claim 7, Robinson in view of Harrold does not specifically teach that in each switchable state of the host material, considering a combination of: the additional polariser; the guest-host liquid crystal retarder and any other retarder arranged between the additional polariser and the reflective polariser; and the reflective polariser, the contribution to the reflectance of the display device provided by that combination and excluding any surface reflections besides reflection from the reflective polariser is at most 15% in all directions inclined to a normal to the display device.
However, Robinson teaches (in figure 5C) teach that in each switchable state of the host material, considering a combination of: the additional polariser; the guest-host liquid crystal retarder and any other retarder arranged between the additional polariser and the reflective polariser; and the reflective polariser, the contribution to the reflectance of the display device provided by that combination and excluding any surface reflections besides reflection from the reflective polariser is at most approximately 20% in all directions inclined to a normal to the display device (paragraph 300) which will be reduced depending on the amount of light absorbing anisotropic material included in the guest-host liquid crystal retarder under the modification from Harrold.
It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. (See MPEP § 2144.05 (II) (A) and (B)). The maximum reflectance of the display device is a result effective variable in that it is directly dependent on the amount of dichroic dye provided in the guest-host liquid crystal retarder and Harrold teaches (in figure 3C) that as the amount of dichroic dye increases display luminance is decreased in the front view resulting in a dimmer display and decreased to a larger degree in the side resulting in increased security.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to set the amount of anisotropic material such that in each switchable state of the host material, considering a combination of: the additional polariser; the guest-host liquid crystal retarder and any other retarder arranged between the additional polariser and the reflective polariser; and the reflective polariser, the contribution to the reflectance of the display device provided by that combination and excluding any surface reflections besides reflection from the reflective polariser is at most 15% in all directions inclined to a normal to the display device in order to balance the need for a bright display and security.
As per claim 8, Robinson in view of Harrold teaches that at least one switchable state of the host material (public/wide angle mode, see figure 9 in Robinson and figure 4G in Harrold), the optical axis of the guest-host liquid crystal retarder has an alignment component perpendicular to the plane of the guest-host liquid crystal retarder (see paragraphs 324-326 in Robinson and paragraphs 242-243 in Harrold).
As per claim 9, Robinson in view of Harrold teaches that the guest material (guest material 414B from Harrold) has a transmission in the visible spectrum that varies with wavelength (the guest material 414B from Harrold comprises pleochroic material, paragraph 212 in Harrold, which absorbs different wavelengths of light differently depending on the direction of incidence of the rays or their plane of polarization, paragraph 156 in Harrold).
As per claim 12, Robinson in view of Harrold does not teach that the anisotropic material comprises an anisotropic metallic nanomaterial.
However, Harrold teaches providing anisotropic silver nanowires in addition to the absorbing dichroic materials (paragraphs 229-230) in order to increase privacy performance (paragraph 234).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include anisotropic metallic nanomaterial in addition to the absorbing dichroic materials in the switchable liquid crystal retarder in Robinson as modified by Harrold.
The motivation would have been to increase privacy performance.
As per claim 13, Robinson in view of Harrold teaches that the anisotropic metallic nanomaterial has a transparent electrically insulating surface layer (see paragraph 231 in Harrold).
As per claim 14, Robinson in view of Harrold teaches that the volume of the guest material is less than 3%, preferably less than 2% and most preferably less than 1% of the volume of the host material (paragraph 219 in Harrold).
As per claim 15, Robinson in view of Harrold teaches that the weight of the guest material is less than 3%, preferably less than 2% and most preferably less than 1% of the weight of the host material (paragraph 219 in Harrold).
As per claim 16, Robinson in view of Harrold teaches that the guest material (guest material 414B from Harrold) comprises a positive dichroic material or a positive pleochroic material (paragraph 212 in Harrold) and in at least one of the states (privacy mode, see figure 3 in Robinson and figure 5A in Harrold), the optical axis of the guest- host liquid crystal retarder has an alignment component in the plane of the guest-host liquid crystal retarder that is orthogonal to the electric vector transmission direction of the display polariser (electric vector transmission direction 219 in Robinson) (paragraph 278 in Robinson).
As per claim 17, Robinson in view of Harrold teaches that the on-axis extinction coefficient of the guest-host liquid crystal retarder in at least one mode of operation is at least 60%, preferably at least 80% and most preferably at least 90% (paragraph 220 in Harrold).
As per claim 18, Robinson in view of Harrold teaches that at least one passive retarder (negative C-plate passive polar control retarder 330 in Robinson) arranged between the additional polariser (additional polariser 318 in Robinson) and the reflective polariser (reflective polariser 302 in Robinson).
As per claim 19, Robinson in view of Harrold teaches that the display polariser (output polariser 218 in Robinson), the reflective polariser (reflective polariser 302 in Robinson) and the additional polariser (additional polariser 318 in Robinson), have electric vector transmission directions that are parallel (paragraph 264 in Robinson).
As per claim 20, Robinson in view of Harrold teaches a backlight (directional backlight 20 in Robinson) arranged to output light, wherein the spatial light modulator (SLM 48 in Robinson) is a transmissive spatial light modulator arranged to receive output light from the backlight (see figure 1A and paragraph 256 in Robinson).
As per claim 21, Robinson in view of Harrold teaches that the spatial light modulator (SLM 48 in Robinson) comprises an emissive spatial light modulator arranged to output light and the display polariser (18 in Robinson) is an output display polariser arranged on the output side of the emissive spatial light modulator (see figure 1B and paragraph 259 in Robinson).
Conclusion
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/ALEXANDER P GROSS/ Primary Examiner, Art Unit 2871
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