JPS59139091A - Display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a display device using light emitting diodes (LEDs).

[Technical background of the invention and its problems]

A normal electric circuit using integrated circuits (IC, LSI) is
It is mainly made with a voltage of about 5 volts. On the other hand, a voltage of around 2 volts is sufficient to cause a normal LED to emit light. Therefore, when applying an electric circuit using an IC to an LED, taking into account the electrical and optical characteristics of the LED, it is common practice to install a resistor in series with the LED and use this as a current limiting resistor for the LED. It is. Conventionally,
The current limiting resistor is generally provided by soldering a large number of commercially available ceramic fixed resistors to a printed circuit board, or by pre-installing the resistor in an LED driving IC. These current limiting resistors have the following problems. First, the configuration in which the fixed resistor is soldered requires a large amount of assembly work and component cost, and there are also problems such as the inability to make the display device compact because the fixed resistor element occupies a large area. on the other hand,
A drive IC with a built-in current-limiting resistor can be made more compact, but in this case, the temperature of the entire IC increases due to heat generation in the built-in resistor section, which has a negative effect on the logic section of the IC. Furthermore, it is necessary to develop and produce a dedicated IC suitable for each display device, which requires a large amount of development and production costs.

Therefore, the reality is that display devices incorporating display-specific ICs are not profitable unless they can be mass-produced and sold in large quantities.

[Purpose of the invention]

The present invention has been made to address these problems, and provides a display device that can be made more compact, prevents thermal damage to the drive circuit, and can be easily manufactured in small quantities to meet the intended use. The purpose is to

[Summary of the invention]

The gist of the present invention is to use a high-density resistor array mainly made of silicon as a resistor for limiting the current of the LED, and this resistor array includes a plurality of resistor elements having different resistance values.

〔Effect of the invention〕

According to the present invention, since a resistor array mainly made of silicon is used, the current limiting resistor can be housed in an extremely small area compared to the conventional case where fixed resistors are soldered. For example, items that require an area of several centimeters square can be stored in a one millimeter square area. Furthermore, since one circuit of the resistor array is about 100 microns, it can be designed with a margin, and more resistor elements than the required number of circuits can be provided. Moreover, since wire bonding process can be applied to the assembly process, assembly can be performed using a very simple method.

On the other hand, compared to conventional drive ICs with built-in resistors, the present invention, which has a separate resistor array mainly made of silicon,
First, since the heat generated in the resistor section is not transferred to the logic circuit section, malfunction of the logic circuit can be eliminated, and furthermore, deterioration and destruction can be prevented. Second, by creating various resistance element parts with different resistance values in the resistor array in advance, it is possible to select the resistance value that meets the requirements, and furthermore, the resistance value can be changed by devising the connection. is also possible. Therefore, the current applied to the LBI (LBI) bearing part can be adjusted by changing the resistance. Thirdly, it is possible to freely select the driving method and display method by combining with commercially available driving ICs and logic circuit ICs. Therefore, there is no need to design and manufacture an IC dedicated to the display device, and it is possible to create a display device that can be used depending on the purpose at a very low cost. In particular, when displaying various patterns such as figures, characters, alphanumeric characters, etc. by configuring a light-emitting display section using LEDs in a matrix, the drive circuit section and the logic circuit section that processes pattern signals can be used in a wide variety of ways. It is necessary to respond to requests.

It can be said that the configuration of the present invention is the most excellent for display devices that display such various patterns.

[Embodiments of the invention]

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of a display device, and FIG. 2 is an enlarged perspective view of a resistor array incorporated into the display device. In Fig. 1, reference numeral 11 denotes a wiring base.This wiring base includes printed wiring 12 and input/output terminals 1 in advance.
3 is formed. For example, when driving a display device using a dynamic method, part of the printed wiring 12
1 to 124 are directly introduced into the display section 14, and the remaining portions 125 to 132 of the printed wiring are introduced from the terminal 13 to the display section via the resistor array 15.

The resistor array 15 is fixed to the cooling section 16 to prevent heat generation.

In such a configuration, to briefly explain the route of the electrical signal when driving the display device and lighting the display, first, the signal output from the external segment driver (not shown) is sent to the terminals 133 to 140. and is transmitted to the resistor array 15. The printed wiring and the resistor array are connected by bonding wires 17. Subsequently, the signal passes through the display section 14 and is led from another terminal to an externally provided digit driver (not shown).

The display section 14 displays numbers using four-digit 8-shaped segments 141, and an L'gD element is connected to each segment by wire bonding (not shown). Current control resistors corresponding to each segment are included in the resistor array 15 at high density. Figure 2 shows resistor Allen 1.
5 is shown in an enlarged perspective view. The resistor array 151 is formed by thermally diffusing phosphorus on a P-type silicon single crystal substrate using silicon oxide as a selective diffusion mask to form an n-type selective diffusion layer 152.
Electrodes 153 are formed at both ends thereof. The resistance value is determined by changing the width, depth, length, or impurity concentration of the diffusion layer. For example, by changing R-1 to dynamic,
If you set the resistance value to about 50 ohm, which is suitable for the pick operation, it will be LE.
An average current of approximately 10 mA is applied to D.

More than the required number of selective diffusion layers 152 are formed in the resistor array 151, and R-2 is provided with a resistance value suitable for static operation, for example, 200 ohms, so that the area surrounded by the dotted line in Figure 2 is A plurality of them are arranged in one circuit. Therefore, when the display unit 14 is operated statically, by connecting R-2 to the wiring bodies 125 to 140, it is possible to turn on the display with almost the same brightness as when operating the display unit 14 in a static manner.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 to 5. Figure 3 shows LEDs arranged in a matrix of 16 rows x 1
FIG. 2 is a plan view of a display device that displays figures arranged in six columns. In FIG. 3, the wiring base 31 has column wiring 3.
2 and row wiring 33 are provided, and an LED 34 is constructed at a location corresponding to the intersection thereof. Each row wiring 33 is connected to a driving IC 36 via a resistor array 35. On the other hand, the column wiring 32 is connected to each LED and IC 36. Image signals and power for displaying graphics are transmitted from the outside to the IC 36 via the input/output terminal 37. In this configuration, the resistor array that limits the current of the LED is as shown in the enlarged perspective view of FIG. 4 or FIG. 5.

The resistor array in FIGS. 4 and 5 is based on a silicon substrate 41.5.
An insulator (not shown) such as silicon oxide is formed on 1, a polycrystalline silicon body 42 and 52 are selectively formed on it, and Alt electrodes 43 and 53 are formed at the ends of the polycrystalline silicon body. This is what I did. The polycrystalline silicon body has a plurality of circuits insulated from each other within the resistor array, and is configured to have different resistance values by selecting and connecting electrodes. For example, in the case of Figure 4, the length of the polycrystalline silicon body is 431
432 and 433 have different resistance values. These three types are arranged in sequence to form a resistor array. In the case of FIG. 5, the resistance value is changed by selecting one side of the electrode.

Although the resistance play, IC, and display device are shown exposed in FIGS. 1 to 5 above,
The final DISGray device will be sealed with resin or the like, and will be configured to provide electrical signals to input/output terminals. It is also possible to provide the resistance play and drive ICs on the back side of the display device so that they are not visible from the display surface side and to enable connection of the display surfaces.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a display device of the present invention, FIG. 3 is a plan view of the display device, and FIGS. 2, 4, and 5 are enlarged perspective views of a resistor array. 11.31... Wiring base, 12, 32.33... Wiring body, 13.37... Input/output terminal, 14.34...
Display body, 15.35...Resistance array, 36...IC
. 152.42.52...Resistance section, 153,43.53
...Electrode, 151.41.51...Silicon base. Agent Patent attorney Noriyuki Chika (and 1 other person) Figure 3-534- Figure 4 Figure 5

Claims (2)

[Claims] (1) A current-limiting resistor array in which a light emitting diode is formed on a wiring base and polysilicon is selectively formed on a silicon base;
Alternatively, a current limiting resistor plate formed by selectively diffusing impurities into a silicon substrate is provided, and the resistor array is provided with a resistor having a resistance value suitable for dynamic operation and static operation of the light emitting diode. A display device featuring: (2) A light-emitting diode on a wiring base, an integrated circuit for driving the light-emitting diode, and a copper group limiting resistor array formed by selectively forming polysilicon on a silicon base, or selectively diffusing impurities into a silicon base. What is claimed is: 1. A display device comprising: a current limiting resistor array formed by the resistor array; the resistor array includes a plurality of circuits having different resistance values; and the resistance value is changed by changing the connection points of the resistor array.