Tetsuya Shiroishi

Emission characteristics of printed carbon nanotube cathodes after laser treatment

Recently, field emission displays using printed carbon nanotubes (CNTs) as an emitter have been researched eagerly. By laser irradiation, some CNTs in the printed CNT layer stand out, and they work as the emission sites. We found that the higher CNTs that are easier to be the emission sites tend to exist at the boundary of the laser irradiation pattern. We used the irradiation patterns that consist of the arrays of microirradiation pattern to increase the total length of boundary. Both emission characteristics and emission uniformity were improved by the increase of the boundary length. We examined several lasers, and the irradiation by the second harmonic generation yttrium aluminum garnet laser of which wavelength was greatest in our experiment provided the best emission characteristics (turn-on electric field <2V∕μm) and emission uniformity (turn-on electric field deviation <5%).

Improvement of emission characteristics uniformity of carbon nanotube field emission display by surface treatment

Carbon nanotubes (CNTs) have been investigated as an emitter for field emission display (FED). In our FED fabrication process, the printed CNTs are raised by a laser irradiation for the purpose to improve the emission characteristics. Because the emitters have to be controlled in each pixel individually on FED, the uniformity of the emission characteristics is necessary. We could improve the emission characteristics uniformity successfully by two methods. In the first method, the distribution of CNT raisings was homogenized by the modification of the irradiation pattern that consisted of an array of small areas. The emission deviation was improved to approximately half by the method. In the second method, the impurities of CNT raisings were cleaned by post-laser-irradiation of which fluence was lower than that of first irradiation. The emission characteristics improved and the turn-on electric field reduced from 2.1 to 1.4V∕μm. The emission deviation also improved to approximately half.

Low-temperature growth of carbon nanotube by thermal chemical vapor deposition with FeZrN catalyst

Recently the direct growth of carbon nanotubes (CNT) on glass substrates by thermal chemical-vapor deposition at low temperatures has been researched for the fabrication of field-emission displays. We have achieved synthesis of CNT on soda lime glass with a catalyst: FeZrN at low temperature (500–550 °C). The FeZrN film deposited by sputtering is amorphous. However, this film changes into a crystalloid to separate out Fe fine particles by thermal treatment. This characteristic has been successfully applied to make the precursor of CNT. There is a possibility that the density and diameter of CNT can be controlled by varying the composition ratio of FeZrN. The emission from CNT has also been obtained. The turn-on electric field has been ∼2.5–3 V/μm. We have fabricated a microtriode structure and the emission has been also recognized.

53.1: Fabrication of CNT Emitter Array with Polymer Insulator

A new method of fabricating CNT emitter array using polymer insulator with low outgassing has been developed. A dry etching process without the damage on the CNT has been found and it proved to decrease the turn-on voltage. Better emission properties than conventional insulator has been obtained.

63.4: Improvement of Emission Uniformity by Heat-Resisting CNT Paste

A heat-resistant paste has been developed to solve the problem of carbon-nanotube (CNT) loss in the heat treatment process after the printing. This paste contains a new glass powder for reductive reaction for CNT. The microscopic observation clarifies the number of CNTs in the new cathode are significantly more than the conventional cathode. The emission distribution measurements show the number of emission sites is 20 percent more than the conventional cathode. The luminance uniformity of new cathode has been significantly improved.

A High-gm and Low Emittance Cathode with Convex Surface

Because of the availability of the internet and digital cameras, the opportunities to enjoy dynamic images and photographs on PC monitors have increased. A cathode with a convex surface has been studied for large screen (i.e. 22in.) high brightness (i.e. 300cd/m2) PC-CRTs. The dimensions of the convex surface were optimized using computer simulations. We obtained an emission current of 1, 300μA, required for 300cd/m2 luminance 22-in. CRTs, with less than a 50-V drive voltage and improved the emittance. We verified significant improvements in the drive and focus characteristics have been verified by prototype CRTs.

Fabrication of CNT field‐emitter array using a polymer insulator

— The fabrication process of a carbon-nanotube (CNT) field-emitter array (FEA) having a polymer insulator is reported. This polymer material is suitable for a large-sized FEA because of its coating property and thermal stability. These features contribute to the display-image uniformity, the tolerance to the thermal-sealing process, etc. A new method of forming via holes on the insulator instead of gate holes has been developed. The method uses a spin-wet-etching (SWE) technique instead of the typical reactive-ion-etching (RIE) method. The RIE method damages and contaminates the CNT at the end of the etching process. However, the SWE technique ensures fine gate hole configurations with little under-cut without any damage nor contamination. An FEA panel 1.5 in. on the diagonal was fabricated by using the method. The FEA showed good emission uniformity with proper surface treatment of the CNT.

Growth of Carbon Nanotube by Thermal Chemical Vapor Deposition at Low Temperature with FeZrN Film

Recently, the direct growth of carbon nanotubes on a glass substrate by thermal chemical vapor deposition (CVD) at low temperatures has been studied for the fabrication of field emission displays (FEDs). We achieved the synthesis of carbon nanotubes on soda lime glass at low temperatures (500–550°C) by a novel granulation method using FeZrN film. The FeZrN film is amorphia direct after sputtering, however, it changes into crystalloid to separate out Fe fine particles by thermal treatment. The characteristic was applied to successfully make the precursor of carbon nanotubes. The emission was also obtained and the turn-on electron field was approximately 3 V/µm.

3D image technique with a grating plate on high-resolution CRT

We propose the 3D image technique using a CRT with a grating plate. The main component of the system is a CRT, a lens and a diffraction plate. We make a composite image on the CRT. The composite image is compounded from several images taken from different view points. This image is focused on the diffraction plate through the lens. There are many pixels of the diffraction gratings that correspond to the pixels of the composite image. Each image is diffracted to different viewing areas by the diffraction gratings. Because we can see one image from each viewing area independently, we can observe 3D image. We made a test system. The size of composite image on the CRT screen is 8-inch. The composite image is compounded from four images. The size of the diffraction grating plate is 3-inch. The width and height of one viewing area is 6 cm by 6 cm and total viewing area is 24 cm by 6 cm. The system is able to divide the composite image into four images and we can observe the images that have perspective.