Fumihiro Namiki

55.1: Invited Paper: High-Luminance and Highly Luminous-Efficient AC-PDP with DelTA Cell Structure

To improve the performance of PDPs, we developed an AC-PDP with the Delta Tri-color Arrangement (DelTA) cell structure and arc-shaped electrodes. The experimental panel has a pixel pitch of 1.08 mm and luminous efficiency of 3 lm/W at a luminance of 200 cd/m2. Moreover, its peak luminance can be greater than 1000cd/m2.

17.3: Improvement of the Speed of Address Discharges in Ne‐Xe‐He Discharge Gases for ACPDPs

The time lag of address discharges is discussed in terms of its relation with discharge gas composition. We measured the discharge time lag in ACPDPs with Ne-Xe-He mixed gases. As the concentration of helium increases, the address discharge time lag becomes shortened because helium atoms reduce mostly the formative time lag of the discharge. The formative time lag depends on the ion drift velocity at the initial stage of discharge formation. This ion drift velocity becomes lager with higher helium atom concentration.

Electro-sound transducer eliminating acoustic multi-reflection, and ultrasonic diagnostic apparatus applying it

An ultrasonic diagnostic apparatus protected from multi-reflection of sound echoes. Multi-reflection is avoided by eliminating the reflection from the surface of an electro-sound transducer. This invention eliminates the surface reflection of the transducer by following three methods: (a) changing a direction of each surface of an array of transducer elements to direct the reflected sound wave away from the main direction of the sound beam; (b) applying an acoustic matching layer to a surface of a piezo-electric device of the transducer to cancel out phases of sound waves reflected by the surfaces of the layer and the device; and (c) providing an acoustic matching surface on a front or back face of the piezo-electric device to cancel out phases of sound waves reflected by the surface of the device.

High‐luminance and highly luminous‐efficient AC‐PDP with DelTA cell structure

To improve PDP performance, we developed an AC-PDP with the Delta Tri-Color Arrangement (DelTA) cell structure and arc-shaped electrodes. The experimental panel has a pixel pitch of 1.08 mm and luminous efficacy of 3 lm/W at a luminance of 200 cd/m 2 despite its conventional gas mixture of Ne and Xe (4%) and conventional phosphor set. Moreover, its peak luminance can be greater than 1000 cd/m 2 . The strong dependence of luminous efficacy on the sustain voltage is also discussed in this paper.

49.1: Development of a Hi-Definition 32-in. PDP

We developed the worlds smallest 32-inch HDTV PDP. By improving the luminous efficiency, a luminance of 650 cd/m2 and power consumption (discharge and driving circuit) of 200 W or less was achieved. Moreover, incorporating an Advanced Color Compensating (ACC) filter improved the PDPs color reproduction capability, better than that of CRTs.

Effect of saw-cut depth on characteristics of array transducer

The authors suggest that saw-cut depth affects the electroacoustic conversion characteristics of an array transducer. To investigate this, they made several samples and measured the impedance of the sawed part of the backing. The results indicate that this impedance is less than that of the solid backing because the acoustic velocity of the sawed part is decreased. Assuming that the sawed part acts as a pseudolayer between the PZT (lead zinc titanate) elements and backing, the authors calculated transducer conversion characteristics by computer simulation. On the basis of the simulation, they built transducers and measured their characteristics. Excellent agreement between the simulation and experiment supports the pseudolayer theory. It is concluded that by making good use of the saw-cut-depth effect, high-efficiency broad-bandwidth transducers can be made.<<ETX>>

P-49: Improvement of Contrast Ratio in Bright-Ambient Color ACPDP with High Resolution

Contrast ratio in bright ambient is one of the most important factor of image quality in display picture. In this paper, it is reported that the contrast ratio is improved by applying a reflective structure with white ribs. The structure is applied to surface discharge ac-PDP with high resolution of 0.13mm, the contrast ratio is improved 1.5times higher than the conventional one. Moreover, luminance and luminous efficiency are improved 1.94 and 2.05 times higher with wider viewing angle.

P-48: Development of a 25-in.-Diagonal SXGA Full-Color PDP

We have successfully developed a 25-inch diagonal SXGA full-color PDP recently. This PDP has characteristics of 0.13mm sub-pixel size, 150cd/m2 luminance and 70:1 contrast ratio. Also, this PDP has 1280 × 1024 pixels in 499.2mm × 399.36mm display area and can show more than 260 thousands colors with the newer developed high speed driving method. Moreover, we developed the new electrical power control method and the new scanning method using display data to reduce power consumption and heating of driver ICS. With these technologies, we are now introducing a 25-inch-diagonal SXGA full-color PDP monitor.

Variation of acoustic impedance caused by a cut in ultrasonic transducers

The authors describe the measurement of the acoustic impedance of the backing of an ultrasonic array transducer consisting of piezoelectric ceramic and backing and matching layers. The transducer is made by sawing the piezoelectric ceramic into array elements. The backing is also cut slightly so that each element can be driven independently, without acoustic cross-coupling between elements. The authors devised a way to measure the acoustic impedance of the sawn part of the backing, which presented difficulties because of its small size. The method uses the reflection coefficient spectrum at the surface of the sawn backing. The measured impedance of the sawed part was 5.33*10/sup 6/ kg/m/sup 2/ s, and that of the solid part was 6.35*10/sup 6/ kg/m/sup 2/ s. It is shown that the impedance of the sawn part of the backing is less than that of the solid backing, even though the material is the same. From this, the array transducers electroacoustic conversion characteristics were obtained by computer simulation, accounting for the effect of the sawn part of the backing, and were in excellent agreement with experiment.<<ETX>>

Development of a high‐definition 32‐in. PDP

We developed the worlds smallest-profile 32-in. HDTV PDP. By improving the luminous efficiency, a luminance of 650 cd/m 2 and power consumption (discharge and driving circuit) of 200 W or less was achieved. Moreover, incorporating an advanced color compensating (ACC) filter improved the PDPs color-reproduction capability, better than that of CRTs.