JPH07123303B2 - Projection Television CRT / lens connection structure - Google Patents

Description

The present invention relates to a CRT / lens in a projection television having a plurality of CRTs (cathode ray tubes) and optically coupling the CRT and the lens through a liquid. Regarding bond structure.

[Prior Art] In a general projection television, as shown in FIG. 4, CRTs (1R), (1G), (for exclusive use of red (R), green (G), and blue (B) are provided. 1B) is a side-by-side three-tube type, and lenses (2R), (2
G), (2B). In this case, regarding the CRTs on both sides (usually R and B), since the distance from the fluorescent screen of the CRT to the screen 3 is different at the center of the screen and is asymmetric, considering the focus on the screen surface, It is necessary to have an appropriate coupling angle α with the lens.

By the way, an optical coupling between the CRT and the lens is filled with a liquid having a refractive index close to that of the glass used for the lens but slightly different, and the optical coupling between the CRT and the lens is performed through this liquid. When the method is adopted, the coupling angle α is α = tan ⁻¹ {n / m, where β is the projection angle to the screen 7, m is the lens magnification, and n is the refractive index of the liquid between the CRT and the lens.・ Tan β}.

Generally, the CRT and the lens are connected by a hollow connecting fitting, and the inside of the connecting fitting is filled with a liquid.
A dedicated connecting metal fitting having a shape corresponding to the required coupling angle α was manufactured, and the CRT and the lens were connected at a geometrical angle α by the dedicated connecting metal fitting.

[Problems to be Solved by the Invention] In the case of an air coupling in which the CRT and the lesbian are simply air, it is possible to connect the two with a coupling fitting that is simply manufactured, but a liquid is interposed. In the case of the above-mentioned optical coupling, it is not easy to change the coupling angle α, because it is necessary to bond the coupling fitting to the CRT and the lens so as to prevent the liquid from leaking, or to make a watertight joint by tight packing.

However, in the above-mentioned conventional CRT / lens coupling structure that simply uses the connecting metal fittings, a dedicated connecting metal fitting is required for each of the R, G, and B CRTs, which has the drawback of complicating the design specifications.

Further, when the screen size is changed, the distance to the screen is changed from the position of reference numeral 3 to the reference numeral 3'in FIG.
Then, the projection angle β is changed to β ′, and the coupling angle α is changed according to the above equation. Therefore, also in this case, a separate connecting fitting is required, and the same problem as described above occurs. Also, when trying to change the screen size of the assembled one, the connecting metal fittings are fixed with a liquid sealing structure,
Its replacement is extremely difficult.

The present invention has been made in view of the above circumstances.
CRT / lens combination structure that can use common connecting metal fittings for different things, simplifies and unifies design specifications, and can easily change screen size etc. even after assembly The purpose is to provide.

[Means for Solving Problems] In the present invention, in order to solve the above problems, a connecting fitting and a CR are used.
A glass plate whose plate thickness changes in a taper shape was inserted into the liquid filled in the space formed by T and the lens in a direction parallel to the CRT and the lens.

[Operation] In the above structure, due to the difference in refractive index between the liquid and the glass plate, the optical distance between the CRT and the lens changes depending on the thickness of the glass plate at the position where the light emitted from the CRT passes. . Therefore, the optical distance continuously changes in the tapered direction, and the coupling angle between the CRT and the lens changes optically.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, 1 is a CRT, 2 is a lens, 5 is a connecting fitting, and this connecting fitting 5 has a hollow structure for connecting the CRT 1 and the lens 2 in parallel and facing each other, and a liquid 6 is filled inside. And is watertightly bonded to the CRT 1 and the lens 2 with an adhesive 7. Then, it is fixed to the chassis 8 with a bolt 10 through a washer 9.

A glass plate 11 having a tapered plate thickness is inserted into the connecting fitting 5. The glass plate 11 is inserted, for example, from the opening 5a opened in the connecting fitting 5 so that the tip side fits into the groove 5b, and is pressed by the lid 12, and the lid 12 is bonded to the opening 5b of the connecting fitting 5. Adopt a structure that is watertightly bonded with an agent.

In the above configuration, although the geometric angle between the CRT1 and the lens 2 is not provided, the tapered glass plate 11 is
And an optical coupling angle α between the lens 2 and the lens 2. This will be described in detail with reference to FIG. 3. As shown in FIG. 3A, a glass-equivalent value of the optical distance between the CRT 1 and the lens 2 facing each other in parallel at the geometrical distance 1 (lens The optical distance converted to the glass used for 2) L ₁ is the lens (glass)
The refractive index of the filled liquid 6 is 1.52, for example.
Let n ₁ be L ₁ = 1.52 l / n ₁ .

Further, as shown in FIG. 6B, the refractive index n ₂ and the plate thickness d in the liquid are
When the parallel glass plate 12 having a uniform thickness is inserted, the optical distance L _{2 in} terms of glass is L ₂ = 1.52 (ld) / n ₁ + 1.52d / n ₂ and the parallel glass plate 12 is inserted. As a result, ΔL = L ₁ −L ₂ = (1.52 / n ₂ −1.52 / n ₁ ) d changes in glass-equivalent optical distance. Since the refractive index n ₁ of the liquid 6 is smaller than the refractive index n ₂ of the parallel glass plate 12, the value of ΔL is negative. That is, by inserting the parallel glass plate 12, the optical distance becomes shorter than the geometrical distance 1.

Therefore, the refractive index is n ₂ as shown in FIG.
When the tapered glass plate 11 having a thickness of zero on the side and a of thickness a on the other end (B) side is inserted, the glass-equivalent optical distance change ΔLA at point A is ΔLA = (1.52 / n ₂ −1.52 / n ₁ ) × 0 = 0 The glass equivalent optical distance difference ΔLB at the point B is ΔLB = (1.52 / n ₂ −1.52 / n ₁ ) · a.

Therefore, assuming that the width of the phosphor screen of CRT1 is c, the optical coupling angle α is α = tan ⁻¹ {(1.52 / n ₂ −1.52 / n ₁ ) · a / c}.

Thus, even if the CRT1 and the lens 2 are geometrically parallel,
By varying the optical distance, the bond angle α will be obtained.

The CRT / lens combination structure described above can be used in the following cases.

For example, a common connecting fitting can be used for each R, G, B CRT and lens. That is, the glass plate 11 is not inserted in the central G CRT, but the left and right C
Glass plates 11 having opposite taper directions are inserted into RTs. In this way, by changing the crow plate 11, R, G,
A predetermined bond angle α can be obtained for each of B.

Further, when the screen size is changed, the projection angle β changes and the engagement angle α changes as described in FIG. 4, but the same can be done by changing the glass plate 11 to a predetermined tapered shape. it can. Further, even when the screen size is changed after assembly, it is only necessary to remove the lid 12 and replace the glass plate 11, so that the screen size can be changed relatively easily.

Regarding the projection angle β itself, since the orientations of the CRT and the entire lens can be changed by changing the thickness of the left and right washers 9, the projection angle β can be easily changed.

[Effects of the Invention] As described above, according to the present invention, a glass plate whose plate thickness changes in a tapered shape is inserted in the liquid of the connecting fitting, so that the common connecting fitting makes the red (R) , CRT of green (R), and blue (B) can be connected to the lens, and the change of the screen size does not need to change the connecting metal fittings and can be easily handled. It has become possible.

Since the connecting fittings can be commonly used in various cases, the design specifications can be simplified and standardized, and the screen size can be changed even after assembly.

[Brief description of drawings]

FIG. 1 is a sectional view of a CRT / lens coupling structure of a projection television showing an embodiment of the present invention, and FIG.
FIG. 3 (a), (b) and (c) are views for explaining the operation of the present invention, and FIG. 4 is a general conceptual diagram of a projection television. 1 ... CRT (cathode ray tube), 2 ... lens, 5 ... connecting metal fitting, 6 ... liquid, 11 ... glass plate.

Claims (1)

[Claims] 1. A plurality of CRTs, each CRT and a lens arranged in front of each CRT are connected through a hollow connecting metal fitting, and the inside of the space formed by the connecting metal fitting, the CRT and the lens is connected. In the CRT / lens connection structure of the projection television in which the CRT and the lens are optically coupled by the filled liquid, the thickness of the plate filled in the liquid filled in the space formed by the connection fitting, the CRT and the lens A CRT in a projection characterized by inserting a glass plate that changes in a taper shape in a direction parallel to the CRT and the lens.
Lens connection structure.