KR200425513Y1 - Mobile phone keypad light emitting assembly using light guide plate - Google Patents

Abstract

The present invention relates to a light emitting assembly of a mobile phone keypad, and more particularly to a mobile phone keypad light emitting assembly that can provide a light emitting function on the back of the keypad using a light emitting diode (LED) and a thin film light guide plate.

The present applicant has filed an application for a mobile phone keypad light emitting assembly using a light guide plate (No. 10-20006-0037405), and will continue to study the areas to be improved in terms of structure and light emission efficiency.

According to the present invention, since the light guide plate is located between the key sheet and the contact portion, structural stability can be ensured, thereby simplifying the manufacturing process and improving the durability of the product, and increasing the brightness of the light. In addition, by controlling the amount of light propagation through the opening of the light guide plate, it is possible to finely adjust the uniformity of light emission.

Light guide plate, mobile phone keypad, light emitting assembly

Description

Keypad back-light assembly of handheld device using light guide plate}

1 is an exploded perspective view of a keypad light emitting assembly according to the present invention.

2 is a cross-sectional view of the keypad light emitting assembly according to the present invention.

<Description of the major reference numerals>

10 key sheet 20 light guide plate

21: opening 22: uneven pattern portion

30: contact portion 40: metal dome portion

50: printed circuit board 51: LED

The present invention relates to a light emitting assembly of a mobile phone keypad, and more particularly to a mobile phone keypad light emitting assembly that can provide a light emitting function on the back of the keypad using a light emitting diode (LED) and a thin film light guide plate.

Since a mobile communication terminal such as a mobile phone should be used at a place where the user wants at night or in a dark place, the light emitting function of the keypad is very important.

Generally, for this purpose, an LED or an EL (Electroluminescent) sheet is used, but in the conventional method, the LED type has high power consumption and nonuniformity of light emission. In addition, the EL type has a problem that the electrical interference occurs and takes a high cost.

Accordingly, the present applicant has filed a design of a mobile phone keypad light emitting assembly using a light guide plate (No. 10-20006-0037405), which is described above by mounting a side emitting LED on one side and transmitting the light to the keypad using the light guide plate. It can be said to be a breakthrough devised to enable ultra-thinning of the keypad while eliminating the problems of the prior art.

However, the areas to be improved in terms of product structure and luminous efficiency should be continuously studied.

The present invention is to improve the uniformity of brightness and light emission, and to provide a more efficient structure in a mobile phone keypad light emitting assembly using a light guide plate.

In order to achieve the above technical problem, the present invention is a printed circuit board mounted only on one side of the LED; A metal dome portion attached to the printed circuit board including a metal dome and a dome tape fixing the same; A contact portion formed on the metal dome portion by forming a concave-convex structure having protrusions at a position corresponding to the metal dome; A light guide plate coupled to the pressure-sensitive portion including an uneven pattern portion having an uneven reflective structure capable of light propagation; And a key sheet coupled to the light guide plate, wherein the LED is mounted at a height that allows light to enter the light guide plate.

Hereinafter, with reference to the drawings will be described in more detail the technical idea of the present invention. However, the same content as mentioned in the first application No. 10-2006-0037405 (hereinafter referred to as the "first application") may be omitted.

1 is an exploded perspective view showing the components and the coupling sequence of the keypad light emitting assembly according to the present invention, the key sheet (10), the light guide plate 20, the contact portion 30, the metal dome portion 40 and printing It includes components roughly divided into a circuit board 50.

The key sheet 10 is generally a panel-type key sheet for ultra-thin cell phones, and the key portion is a light transmitting member so that the key portion can be recognized when light is emitted. The key sheet may be implemented in various forms and materials according to the prior art.

The light guide plate 20 aims at uniform diffusion of light incident from the LED, and includes an open part 21, an uneven pattern part 22, and an outer light shielding part (not shown).

The opening portion 21 cuts out the light guide plate sheet in a predetermined shape so that light can pass through the light guide plate as it is. That is, the opening part serves to reduce the amount of propagation by dissipating light, and can improve the uniformity of light emission by including the opening part of a proper position and shape according to the structural characteristics of each product.

Concave-convex pattern portion 22 is a concave-convex formed on the light guide plate for light propagation through reflection, and is implemented by a press operation according to a pattern determined at a position corresponding to the translucent member of the key sheet.

 The press operation may press the light guide plate directly into a mold or work on the coated surface after hard coating the light guide plate.

Concave-convex pattern indicates a concave-convex reflection structure that is concentrated so that light is concentrated on the light transmitting member of the key sheet. Concave-convex itself can be formed in various ways according to the characteristics or design of the product such as dot or strip shape. Similarly, the key portion adjacent to the LED is designed to have a small and low unevenness to allow a lot of light to pass through, and the farther away from the light source, the larger and denser the uneven pattern is to prevent the passage of light and preserve more light.

The outer light shield prevents the loss of light to the side of the light guide plate and allows light from the LED to enter the pattern portion of the light guide plate well. In addition, it is preferable to introduce an LED cover (not shown) that covers the exposed LED, such as a prior application, for light blocking upward of the light guide plate. However, since the key sheet is in close contact with the top of the light guide plate, the key sheet itself serves as a light shielding film. You may.

The contact portion 30 forms a concave-convex structure having protrusions at positions corresponding to the metal dome and is positioned on the metal dome portion. This generally serves to enhance the touch feeling when the user presses a key and induce an accurate selection. A material such as rubber, which is durable and has high elasticity or high adhesive force, is used.

As such, the key sheet 10, the light guide plate 20, and the contact portion 30 are coupled to each other to form a keypad part. The light guide plate is fixed between the contact portion directly under the key sheet and the key sheet is light guide plate. Since the light-shielding film may also serve as a close contact with the upper part, the subsequent process may be stable and simplified, and thus, the overall manufacturing may be easy, and the stability and sufficient brightness of the light guide plate itself may be secured.

That is, unlike the prior application in which the light guide plate is located on the metal dome part, the light guide plate is located on the upper layer of the contact part, thereby releasing structurally from the local pressure of the contact part to extend the life of the light guide plate, and to maintain a predetermined interval on the uneven metal dome part. The structural instability that needs to be maintained and supported can be avoided, thereby increasing the durability of the product and simplifying the entire manufacturing process.

In addition, since the light guide plate and the key sheet directly contact each other, the amount of light emitted through the key sheet increases.

The metal dome portion 40 generally includes a metal dome 41 and a dome tape 42 for fixing the metal dome 41. The metal dome portion 40 transmits a key selection of a user to the printed circuit board in response to the protruding portion of the contact portion to drive the circuit. It acts as a switch.

The printed circuit board 50 adopts the conventional technology as it is, but in the nature of the present invention using the light guide plate when mounting the LED 51 employs the LED emitting side light, it is installed only on one side of the printed circuit board.

However, since light of the LED must be incident on the light guide plate, it is important to appropriately adjust the height of the LED 51 as shown in the cross-sectional view of FIG. 2. In this case, in order for the LED to be mounted on the printed circuit board and incident light to the light guide plate, the metal dome, the contacting part, and the light guide plate positioned on the printed circuit board should be able to secure the position of the LED by opening the overlapping part with the LED.

According to the present invention, since the light guide plate is located between the key sheet and the contact portion, structural stability can be ensured, thereby simplifying the manufacturing process and improving the durability of the product, and increasing the brightness of the light.

In addition, by controlling the amount of light propagation through the opening of the light guide plate, it is possible to finely adjust the uniformity of light emission.

Claims (7)

A printed circuit board having an LED mounted on only one side thereof; A metal dome portion attached to the printed circuit board including a metal dome and a dome tape fixing the same; A contact portion formed on the metal dome portion by forming a concave-convex structure having protrusions at a position corresponding to the metal dome; A light guide plate coupled to the pressure-sensitive portion including an uneven pattern portion having an uneven reflective structure capable of light propagation; And a key sheet coupled to the light guide plate, wherein the LED is mounted at a height that allows light to enter the light guide plate. The keypad assembly of claim 1, wherein the LED mounted on the printed circuit board provides a side light emitting function. The mobile phone keypad light emitting assembly of claim 1, wherein the light guide plate includes an opening. The mobile phone keypad light emitting assembly of claim 1, wherein the light guide plate includes an outer light shielding portion. The keypad assembly of claim 1, wherein the light guide plate comprises an LED cover. The mobile phone keypad light emitting assembly of claim 1, wherein the metal dome part, the pressure contact part, and the light guide plate are opened to allow the LED to be positioned at a portion overlapping the LED mounted on the printed circuit board. The keypad assembly of claim 1, wherein the uneven pattern portion of the light guide plate is designed to have smaller and lower unevenness as the key portion adjacent to the LED is formed, and the uneven pattern is designed to be larger and denser as the distance from the LED increases.

Images