Display unit

Disclosed is a display unit provided with a display control printed circuit board with a circuit configured to generate a display signal for display by a display panel and a fixing metal plate for securing the display control printed circuit board. The display control printed circuit board is provided with identification information reading means for reading identification information of the display panel, a memory stored with set values for generating display signals corresponding to the sizes of a plurality of display panels, and a display controller configured to generate the display signals. The fixing metal plate comprises one or more members electrically connected to the display control printed circuit board and configured to transmit the identification information of the display unit to the display control printed circuit board. The identification information reading means reads a set value for the display panel from the memory, based on the identification information of the display panel derived from the one or more electrically connected members, and sets the set values in the display controller configured to generate the display signals.

RELATED APPLICATION DATA

This application claims priority under 35 U.S.C. §119 and/or §365 to Japanese Application No. 2015-065881 filed Mar. 27, 2015, the entire contents is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a display unit adapted to be mounted on various electronic apparatuses.

Description of the Related Art

As described in Japanese Patent Application Laid-Open No. 2011-203399, a display unit that combines a display panel and a control circuit for controlling the display panel is based on a well-known technique.

The display control printed circuit board2is mounted with a display controller5for generating a display control signal, a central processing unit (CPU)3for setting the display controller5, and a memory4stored with set values for the display panel10.

The display signal generated by the display control printed circuit board2is transmitted from a display signal connector6of the printed circuit board2to the display panel10by a display signal cable7. The display panel10varies in resolution (number of pixels displayed on a screen), dot clock (clock as a reference for transfer per pixel), horizontal scanning frequency (updated number of lines capable of being displayed in each second), and vertical scanning frequency (number of screens updated in each second), depending on its size. For a correct display, therefore, it is necessary to identify the size of the display panel10, generate the display signal conforming to the specifications of the display panel10, and send it to the display panel10. A correct display cannot be obtained if the display signal does not conform to the specifications of the display panel10.

FIG. 2shows a configuration and processing of the display control printed circuit board2. The CPU3reads identification information (hereinafter referred to as “ID”) of the display panel10(numeral11), reads a set value corresponding to the ID from the memory4(numeral12), and sets the resolution, dot clock, horizontal scanning frequency, vertical scanning frequency, and the like for the display controller5(numeral13). The display controller5generates the display signal according to the set values and transmits it to the display panel10(numeral14).

Since the display panel10does not have its own ID, the CPU3cannot read any ID of the display panel10from the display signal connector6ofFIG. 1. Instead, a circuit for identifying the ID of the display panel10should be mounted on the display control printed circuit board2so that the CPU3can read the ID. In this case, however, types required for the printed circuit board2are as many as those for the display panel10to be combined therewith.

If a large number of types are provided for the display control printed circuit board2, the manufacture requires production control based on the types for the liquid-crystal display unit1to be shipped. In assembling the liquid-crystal display unit1, moreover, the printed circuit board2may possibly be assembled by mistake.

Further, at the time of maintenance of the liquid-crystal display unit1, the display control printed circuit board2varies depending on the size of the display panel10of the liquid-crystal display unit1, so that the number of maintenance parts increases. In some cases, furthermore, the printed circuit board2may be wrongly mounted at the time of replacement.

SUMMARY OF THE INVENTION

Accordingly, the object of the present invention is to provide a display unit in which a display control printed circuit board can be shared in common without regard to the size of a display panel.

A display unit according to the present invention is characterized in that a display control printed circuit board and a fixing metal plate are provided with a structure for acquiring an ID of a display panel. If the size of the display panel varies, the shape of the fixing metal plate on which the display panel is mounted varies. More specifically, the display panel and the fixing metal plate are directly related in size, so that the ID of the display panel is identified by identifying that of the fixing metal plate. Thus, the display control printed circuit board can be shared in common without regard to the size of the display panel. In some cases, even display panels of the same size may be differently set for a display controller due to differences in resolution or the like. However, means according to the present invention can be applied by maintaining the direct relationship with the metal plate.

Further, the display unit according to the present invention comprises a display control printed circuit board with a circuit configured to generate a display signal for display by a display panel and a fixing metal plate for securing the display control printed circuit board. The display control printed circuit board comprises identification information reading means for reading identification information of the display panel, a memory stored with set values for generating display signals corresponding to the sizes of a plurality of display panels, and a display controller configured to generate the display signals. The fixing metal plate comprises one or more members electrically connected to the display control printed circuit board and configured to transmit the identification information of the display unit to the display control printed circuit board. The identification information reading means reads a set value for the display panel from the memory, based on the identification information of the display panel derived from the one or more electrically connected members, and sets the set values in the display controller configured to generate the display signals.

According to the configuration of the present invention, there can be provided a display unit in which a display control printed circuit board can be shared in common without regard to the size of a display panel.

The fixing metal plate and the display control printed circuit board may be electrically connected to each other by a member or members for securing the display control printed circuit board to the fixing metal plate.

The fixing metal plate and the display control printed circuit board may be electrically connected to each other by a dedicated pin or pins.

The identification information of the display panel may be transmitted from the fixing metal plate to the display control printed circuit board by a combination of the one or more members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described with reference to the accompanying drawings. Like reference numerals are used to designate the same or similar configurations as those of the prior art.

FIG. 3shows an embodiment of the present invention in which a fixing metal plate8is provided with studs9for securing a display control printed circuit board2such that the printed circuit board2can be secured to the studs9on the fixing metal plate8by screws15. The printed circuit board2is mounted with a display controller5for generating a display control signal, a central processing unit (CPU)3for setting the display controller5, and a memory4stored with set values for a display panel10.

The display panel10(not shown inFIG. 3), like the one shown inFIG. 1, is mounted on the surface of the fixing metal plate8opposite to the display control printed circuit board2. The printed circuit board2is provided with one or more threaded holes16through which the screws15are passed. The studs9on the fixing metal plate8are provided with threaded holes (not shown) to be fitted with the screws15, individually.

On the display control printed circuit board2shown inFIG. 3, the CPU3reads identification information (hereinafter referred to as “ID”) of the display panel10, reads a set value corresponding to the ID from the memory4, and sets the resolution, dot clock, horizontal scanning frequency, vertical scanning frequency, and the like for the display controller5. The display controller5generates the display signal according to the set values and transmits it to the display panel10.

As shown inFIG. 4, ID pads ID5-ID1are formed by providing pads17or other structures that electrically contact the studs on the fixing metal plate8around the threaded holes16in the surface of the display control printed circuit board2on the side of the fixing metal plate8(seeFIG. 2). Further, one pad is electrically connected to GND for display control.

The ID pads ID5-ID1are configured to read electrical information (1 or 0) from the CPU3on the display control printed circuit board2, as shown inFIG. 5. The ID pads ID5-ID1are previously pulled up in the printed circuit board2so that they can electrically read “1” if they are open without electrically contacting the fixing metal plate8and read “0” if GND is connected on the fixing metal plate8.

On the side of the fixing metal plate8, the studs9are made electrically conductive or non-conductive depending on the size of the display panel10so that the ID pads of the display control printed circuit board2indicative of the size of the display panel10are made to conduct to GND. The CPU3on the printed circuit board2can identify the size of the display panel10from the ID of the fixing metal plate8by reading signals from the ID pads.

FIG. 6is a view showing a specific example of the display control printed circuit board2. The ID of the fixing metal plate for display size A, that is, the display panel10, is assumed to be ID5-ID1=01011. In this case, as shown inFIG. 6, the studs that contact the pads ID3, ID5, and GND of the printed circuit board2become conductive studs. As shown inFIG. 7, in this case, the pads ID3and ID5are made to conduct to GND by the metal plate. Consequently, ID5-ID1can be read as 01011. Based on this ID, the CPU3reads the set value of the display panel10stored in the memory4, as shown inFIG. 2, and sets the display controller5.

A circuit of a display control printed circuit board2of Embodiment 2 is the same as that of Embodiment 1 (seeFIGS. 3 to 6). In Embodiment 2, however, the printed circuit board2and a fixing metal plate8are brought into electrical contact with each other by an alternative method. As shown inFIG. 8, the printed circuit board2is provided with pads ID5-ID1for contact with pins to be brought into contact with the fixing metal plate8.

The ID pads ID5-ID1are configured to read electrical information (1 or 0) from a CPU3on the display control printed circuit board2, as shown inFIG. 5. The ID pads ID5-ID1are previously pulled up in the printed circuit board2so that they can electrically read “1” if they are open without electrically contacting the fixing metal plate8and read “0” if GND is connected on the fixing metal plate8.

On the side of the fixing metal plate8, electrical information on the ID pads of the display control printed circuit board2can be set to “0” by providing the electrically conductive pins18in the positions of the ID pads to be connected to GND, depending on the size of a display panel10.

Each conductive pin18may be a probe-like structure attached to the fixing metal plate8after its manufacture or means shaped by folding the material of the fixing metal plate8. In the example ofFIG. 9, the conductive pins18are provided on the same surface of the fixing metal plate8as studs9so as to correspond in position to ID pads ID3and ID15, individually.

The ID pads ID3and ID5in the display control printed circuit board2are connected to GND by assembling the printed circuit board2to the fixing metal plate8by means of the studs9. Consequently, the ID of this fixing metal plate, that is, the ID of the display panel, can be read as ID5-ID1=01011. Based on this ID, the CPU3reads the set value of the display panel10stored in a memory4, as shown inFIG. 2, and sets a display controller5.

A circuit for identifying the ID of the display panel10is mounted on a fixing metal plate8. A CPU3may be made to read the ID through means for electrically connecting a display control printed circuit board2and the fixing metal plate8.

While embodiments of the present invention have been described herein, the invention is not limited to the above-described embodiments and may be suitably modified and embodied in various forms.