The latest e-book disassembly evaluation series report (3): Some products still have low brightness

An engineer commented that the circuit architecture looks quite close to the design concept of the mobile phone, and that the processor, 3G communication module and other parts are neatly arranged. This is very similar to Amazon.com's Kindle 2 design.

However, careful inspection of individual components revealed that there were some subtle differences between the two models, such as (1) different battery positions; (2) different antenna sizes and (3) different ways of fixing electronic paper.

Regarding (1) the location of the battery, the Reader Daily Edition is in the lower part of the body, while the nook is placed in the middle (Figure 6). The batteries are quite heavy, about 32g to 35g, and the different positions "have a very different feel for them," one of the engineers said.

On the performance parameter table, Reader Daily Edition weighs 361g and nook is 343g. Although the Reader Daily Edition is slightly heavier, it actually feels lighter than the nook. There are two reasons for this. First, because the heavy battery is placed in the lower part of the device, the overall center of gravity moves down.

The nook, the operation touch screen LCD touch panel is arranged in the lower part of the device. The user is primarily operating here, but the battery is placed on top of it (Figure 6). This is one of the reasons why nook feels heavy.

Figure 6 different battery locations

Reader Daily Edition and nook battery and touch panel location. Nook put the battery on top of the touch panel.

Exterior style considerations lead to design difficulties

(2) The antenna sizes of the two readers vary widely. The Reader Daily Edition has a large, rugged antenna, and the nook has a very simple antenna.

What makes this difference is the exterior design. Sony has a high-grade feel, and its front cover uses aluminum instead of resin (Figure 7). However, aluminum makes the design more difficult, such as reducing the sensitivity of antenna reception, so Sony's antenna becomes larger.

Sony Electronics' Noguchi explained, "When I told the designer to use the aluminum casing, he asked me if it was serious. It is impossible to attach the antenna to the back of the aluminum case in the design of the phone. However, I understand me. The style of the product must be a top priority. After a trial and error design process, the antenna size is increased and the position of the outer casing is kept as far as possible until the current result is achieved."

Figure 7 Advanced appearance of the aluminum casing

The Reader Daily Edition uses an aluminum case for an advanced look. Copper foil is found inside, which may be used to suppress the noise of 3G communication.

The upper part of the back of the e-paper module is covered with copper foil (Fig. 7). “This is obviously an additional anti-noise component,” one engineer said. There is a place where the antenna is installed, and therefore it is considered as a measure for preventing noise of communication. In order to emphasize style, it is clear that more solutions are needed than expected. However, nook has none of these.

Improve anti-drop performance

(3) The electronic paper fixing method also differs greatly between the two. The Reader Daily Edition approach is so complex that an engineer blurted out "Is this complexity necessary?" The electronic paper mold is assembled on a complex three-dimensional chassis (Figure 8), intended to avoid distortion of the outer casing.

Figure 8 Different methods of fixing electronic paper

The Reader Daily Edition's electronic paper mold is assembled on a complex stereo chassis, and nook simply clips the electronic paper module between the iron plate and the protective layer.

The nook electronic paper module is only sandwiched between the iron plate (back) and the protective case (front). Glued to the outer casing.

It is speculated that this difference may be due to the different emphasis on impact resistance (such as reader drop). One of the engineers said, "Reader Daily Edition is clearly impact-resistant." A display manufacturer said that some e-paper readers on the market now have broken electronic paper. Perhaps the difference between Sony, the experienced e-book provider, and Barnes & Noble, the newcomer.

There is still a problem of low screen brightness

We have identified a problem with the Reader Daily Edition that the touch panel is mounted on top of the electronic paper, to some extent obscuring the brightness of the display. Remove the touch panel and view the e-paper directly. The image is very clear and completely different from the actual product screen (Figure 9).

Figure 9 Touch panel reduces display brightness

The Reader Daily Edition uses an impedance film touch panel on top of the electronic paper, causing the screen to be darker and blurry than the electronic paper itself.

The Reader Daily Edition uses a resistive film touch panel with a typical transparency of approximately 95%. When the electronic paper is reflective, the eye sees the light passing through the touch panel twice. Compared to a device that uses a backlight with an LCD panel in combination with a thin film resistive touch panel, the displayed image is dim and blurred anyway.

Sony's model seems to have chosen the latter in terms of slightly degraded display and improved operability. Noguchi of Sony Electronics said, "We chose the best touch panel on the market including sensitivity, and the brightness of the display is a problem to be solved in the future." Manufacturers who want to use the touch panel in the same way, see Will face the same problem.

Android is installed on an SD card

Nook uses the Android software platform of Google. In addition to the e-book reading application and the proprietary UI, Android provides almost everything you need for an e-book terminal. One of the reasons why Barnes & Noble is estimated to be used may be that it offers a shorter development advantage in market introduction time.

Android is stored on a microSD card (Figure 10). Usually the operating system (OS) is stored in flash memory or the like and cannot be easily accessed from the outside. An engineer involved in the dismantling said: "This is a viable method in terms of the ease of upgrading the version or improving the efficiency of the SD card, which is already very cheap today."

Figure 10 Core Confirmation

Android is stored on a microSD card. Read from the memory card (marked at the red line) here, showing that the boot core of the Linux (Android) OS is stored on the microSD card. (End of the article)

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